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v4.6
 
   1/*
   2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3 * Written by Alex Tomas <alex@clusterfs.com>
   4 *
   5 * Architecture independence:
   6 *   Copyright (c) 2005, Bull S.A.
   7 *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21 */
  22
  23/*
  24 * Extents support for EXT4
  25 *
  26 * TODO:
  27 *   - ext4*_error() should be used in some situations
  28 *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29 *   - smart tree reduction
  30 */
  31
  32#include <linux/fs.h>
  33#include <linux/time.h>
  34#include <linux/jbd2.h>
  35#include <linux/highuid.h>
  36#include <linux/pagemap.h>
  37#include <linux/quotaops.h>
  38#include <linux/string.h>
  39#include <linux/slab.h>
  40#include <asm/uaccess.h>
  41#include <linux/fiemap.h>
  42#include <linux/backing-dev.h>
 
  43#include "ext4_jbd2.h"
  44#include "ext4_extents.h"
  45#include "xattr.h"
  46
  47#include <trace/events/ext4.h>
  48
  49/*
  50 * used by extent splitting.
  51 */
  52#define EXT4_EXT_MAY_ZEROOUT	0x1  /* safe to zeroout if split fails \
  53					due to ENOSPC */
  54#define EXT4_EXT_MARK_UNWRIT1	0x2  /* mark first half unwritten */
  55#define EXT4_EXT_MARK_UNWRIT2	0x4  /* mark second half unwritten */
  56
  57#define EXT4_EXT_DATA_VALID1	0x8  /* first half contains valid data */
  58#define EXT4_EXT_DATA_VALID2	0x10 /* second half contains valid data */
  59
  60static __le32 ext4_extent_block_csum(struct inode *inode,
  61				     struct ext4_extent_header *eh)
  62{
  63	struct ext4_inode_info *ei = EXT4_I(inode);
  64	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  65	__u32 csum;
  66
  67	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  68			   EXT4_EXTENT_TAIL_OFFSET(eh));
  69	return cpu_to_le32(csum);
  70}
  71
  72static int ext4_extent_block_csum_verify(struct inode *inode,
  73					 struct ext4_extent_header *eh)
  74{
  75	struct ext4_extent_tail *et;
  76
  77	if (!ext4_has_metadata_csum(inode->i_sb))
  78		return 1;
  79
  80	et = find_ext4_extent_tail(eh);
  81	if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  82		return 0;
  83	return 1;
  84}
  85
  86static void ext4_extent_block_csum_set(struct inode *inode,
  87				       struct ext4_extent_header *eh)
  88{
  89	struct ext4_extent_tail *et;
  90
  91	if (!ext4_has_metadata_csum(inode->i_sb))
  92		return;
  93
  94	et = find_ext4_extent_tail(eh);
  95	et->et_checksum = ext4_extent_block_csum(inode, eh);
  96}
  97
  98static int ext4_split_extent(handle_t *handle,
  99				struct inode *inode,
 100				struct ext4_ext_path **ppath,
 101				struct ext4_map_blocks *map,
 102				int split_flag,
 103				int flags);
 104
 105static int ext4_split_extent_at(handle_t *handle,
 106			     struct inode *inode,
 107			     struct ext4_ext_path **ppath,
 108			     ext4_lblk_t split,
 109			     int split_flag,
 110			     int flags);
 111
 112static int ext4_find_delayed_extent(struct inode *inode,
 113				    struct extent_status *newes);
 
 
 
 
 
 
 
 
 
 
 
 
 114
 115static int ext4_ext_truncate_extend_restart(handle_t *handle,
 116					    struct inode *inode,
 117					    int needed)
 118{
 119	int err;
 120
 121	if (!ext4_handle_valid(handle))
 122		return 0;
 123	if (handle->h_buffer_credits > needed)
 124		return 0;
 125	err = ext4_journal_extend(handle, needed);
 126	if (err <= 0)
 127		return err;
 128	err = ext4_truncate_restart_trans(handle, inode, needed);
 129	if (err == 0)
 130		err = -EAGAIN;
 131
 132	return err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 133}
 134
 135/*
 136 * could return:
 137 *  - EROFS
 138 *  - ENOMEM
 139 */
 140static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 141				struct ext4_ext_path *path)
 142{
 
 
 143	if (path->p_bh) {
 144		/* path points to block */
 145		BUFFER_TRACE(path->p_bh, "get_write_access");
 146		return ext4_journal_get_write_access(handle, path->p_bh);
 
 
 
 
 
 
 
 
 
 147	}
 148	/* path points to leaf/index in inode body */
 149	/* we use in-core data, no need to protect them */
 150	return 0;
 151}
 152
 153/*
 154 * could return:
 155 *  - EROFS
 156 *  - ENOMEM
 157 *  - EIO
 158 */
 159int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 160		     struct inode *inode, struct ext4_ext_path *path)
 
 161{
 162	int err;
 163
 164	WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 165	if (path->p_bh) {
 166		ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 167		/* path points to block */
 168		err = __ext4_handle_dirty_metadata(where, line, handle,
 169						   inode, path->p_bh);
 
 
 
 170	} else {
 171		/* path points to leaf/index in inode body */
 172		err = ext4_mark_inode_dirty(handle, inode);
 173	}
 174	return err;
 175}
 176
 
 
 
 177static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 178			      struct ext4_ext_path *path,
 179			      ext4_lblk_t block)
 180{
 181	if (path) {
 182		int depth = path->p_depth;
 183		struct ext4_extent *ex;
 184
 185		/*
 186		 * Try to predict block placement assuming that we are
 187		 * filling in a file which will eventually be
 188		 * non-sparse --- i.e., in the case of libbfd writing
 189		 * an ELF object sections out-of-order but in a way
 190		 * the eventually results in a contiguous object or
 191		 * executable file, or some database extending a table
 192		 * space file.  However, this is actually somewhat
 193		 * non-ideal if we are writing a sparse file such as
 194		 * qemu or KVM writing a raw image file that is going
 195		 * to stay fairly sparse, since it will end up
 196		 * fragmenting the file system's free space.  Maybe we
 197		 * should have some hueristics or some way to allow
 198		 * userspace to pass a hint to file system,
 199		 * especially if the latter case turns out to be
 200		 * common.
 201		 */
 202		ex = path[depth].p_ext;
 203		if (ex) {
 204			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 205			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 206
 207			if (block > ext_block)
 208				return ext_pblk + (block - ext_block);
 209			else
 210				return ext_pblk - (ext_block - block);
 211		}
 212
 213		/* it looks like index is empty;
 214		 * try to find starting block from index itself */
 215		if (path[depth].p_bh)
 216			return path[depth].p_bh->b_blocknr;
 217	}
 218
 219	/* OK. use inode's group */
 220	return ext4_inode_to_goal_block(inode);
 221}
 222
 223/*
 224 * Allocation for a meta data block
 225 */
 226static ext4_fsblk_t
 227ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 228			struct ext4_ext_path *path,
 229			struct ext4_extent *ex, int *err, unsigned int flags)
 230{
 231	ext4_fsblk_t goal, newblock;
 232
 233	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 234	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 235					NULL, err);
 236	return newblock;
 237}
 238
 239static inline int ext4_ext_space_block(struct inode *inode, int check)
 240{
 241	int size;
 242
 243	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 244			/ sizeof(struct ext4_extent);
 245#ifdef AGGRESSIVE_TEST
 246	if (!check && size > 6)
 247		size = 6;
 248#endif
 249	return size;
 250}
 251
 252static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 253{
 254	int size;
 255
 256	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 257			/ sizeof(struct ext4_extent_idx);
 258#ifdef AGGRESSIVE_TEST
 259	if (!check && size > 5)
 260		size = 5;
 261#endif
 262	return size;
 263}
 264
 265static inline int ext4_ext_space_root(struct inode *inode, int check)
 266{
 267	int size;
 268
 269	size = sizeof(EXT4_I(inode)->i_data);
 270	size -= sizeof(struct ext4_extent_header);
 271	size /= sizeof(struct ext4_extent);
 272#ifdef AGGRESSIVE_TEST
 273	if (!check && size > 3)
 274		size = 3;
 275#endif
 276	return size;
 277}
 278
 279static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 280{
 281	int size;
 282
 283	size = sizeof(EXT4_I(inode)->i_data);
 284	size -= sizeof(struct ext4_extent_header);
 285	size /= sizeof(struct ext4_extent_idx);
 286#ifdef AGGRESSIVE_TEST
 287	if (!check && size > 4)
 288		size = 4;
 289#endif
 290	return size;
 291}
 292
 293static inline int
 294ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 295			   struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 296			   int nofail)
 297{
 298	struct ext4_ext_path *path = *ppath;
 299	int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 
 
 
 
 300
 301	return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 302			EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 303			EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 304			(nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 305}
 306
 307/*
 308 * Calculate the number of metadata blocks needed
 309 * to allocate @blocks
 310 * Worse case is one block per extent
 311 */
 312int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 313{
 314	struct ext4_inode_info *ei = EXT4_I(inode);
 315	int idxs;
 316
 317	idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 318		/ sizeof(struct ext4_extent_idx));
 319
 320	/*
 321	 * If the new delayed allocation block is contiguous with the
 322	 * previous da block, it can share index blocks with the
 323	 * previous block, so we only need to allocate a new index
 324	 * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 325	 * an additional index block, and at ldxs**3 blocks, yet
 326	 * another index blocks.
 327	 */
 328	if (ei->i_da_metadata_calc_len &&
 329	    ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 330		int num = 0;
 331
 332		if ((ei->i_da_metadata_calc_len % idxs) == 0)
 333			num++;
 334		if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 335			num++;
 336		if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 337			num++;
 338			ei->i_da_metadata_calc_len = 0;
 339		} else
 340			ei->i_da_metadata_calc_len++;
 341		ei->i_da_metadata_calc_last_lblock++;
 342		return num;
 343	}
 344
 345	/*
 346	 * In the worst case we need a new set of index blocks at
 347	 * every level of the inode's extent tree.
 348	 */
 349	ei->i_da_metadata_calc_len = 1;
 350	ei->i_da_metadata_calc_last_lblock = lblock;
 351	return ext_depth(inode) + 1;
 352}
 353
 354static int
 355ext4_ext_max_entries(struct inode *inode, int depth)
 356{
 357	int max;
 358
 359	if (depth == ext_depth(inode)) {
 360		if (depth == 0)
 361			max = ext4_ext_space_root(inode, 1);
 362		else
 363			max = ext4_ext_space_root_idx(inode, 1);
 364	} else {
 365		if (depth == 0)
 366			max = ext4_ext_space_block(inode, 1);
 367		else
 368			max = ext4_ext_space_block_idx(inode, 1);
 369	}
 370
 371	return max;
 372}
 373
 374static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 375{
 376	ext4_fsblk_t block = ext4_ext_pblock(ext);
 377	int len = ext4_ext_get_actual_len(ext);
 378	ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 379	ext4_lblk_t last = lblock + len - 1;
 380
 381	if (len == 0 || lblock > last)
 
 
 
 
 
 382		return 0;
 383	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 384}
 385
 386static int ext4_valid_extent_idx(struct inode *inode,
 387				struct ext4_extent_idx *ext_idx)
 388{
 389	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 390
 391	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 392}
 393
 394static int ext4_valid_extent_entries(struct inode *inode,
 395				struct ext4_extent_header *eh,
 396				int depth)
 
 397{
 398	unsigned short entries;
 
 
 
 399	if (eh->eh_entries == 0)
 400		return 1;
 401
 402	entries = le16_to_cpu(eh->eh_entries);
 403
 404	if (depth == 0) {
 405		/* leaf entries */
 406		struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 407		struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 408		ext4_fsblk_t pblock = 0;
 409		ext4_lblk_t lblock = 0;
 410		ext4_lblk_t prev = 0;
 411		int len = 0;
 
 
 
 412		while (entries) {
 413			if (!ext4_valid_extent(inode, ext))
 414				return 0;
 415
 416			/* Check for overlapping extents */
 417			lblock = le32_to_cpu(ext->ee_block);
 418			len = ext4_ext_get_actual_len(ext);
 419			if ((lblock <= prev) && prev) {
 420				pblock = ext4_ext_pblock(ext);
 421				es->s_last_error_block = cpu_to_le64(pblock);
 422				return 0;
 423			}
 
 424			ext++;
 425			entries--;
 426			prev = lblock + len - 1;
 427		}
 428	} else {
 429		struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 
 
 
 
 
 
 
 
 430		while (entries) {
 431			if (!ext4_valid_extent_idx(inode, ext_idx))
 432				return 0;
 
 
 
 
 
 
 
 433			ext_idx++;
 434			entries--;
 
 435		}
 436	}
 437	return 1;
 438}
 439
 440static int __ext4_ext_check(const char *function, unsigned int line,
 441			    struct inode *inode, struct ext4_extent_header *eh,
 442			    int depth, ext4_fsblk_t pblk)
 443{
 444	const char *error_msg;
 445	int max = 0, err = -EFSCORRUPTED;
 446
 447	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 448		error_msg = "invalid magic";
 449		goto corrupted;
 450	}
 451	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 452		error_msg = "unexpected eh_depth";
 453		goto corrupted;
 454	}
 455	if (unlikely(eh->eh_max == 0)) {
 456		error_msg = "invalid eh_max";
 457		goto corrupted;
 458	}
 459	max = ext4_ext_max_entries(inode, depth);
 460	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 461		error_msg = "too large eh_max";
 462		goto corrupted;
 463	}
 464	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 465		error_msg = "invalid eh_entries";
 466		goto corrupted;
 467	}
 468	if (!ext4_valid_extent_entries(inode, eh, depth)) {
 
 
 
 
 469		error_msg = "invalid extent entries";
 470		goto corrupted;
 471	}
 
 
 
 
 472	/* Verify checksum on non-root extent tree nodes */
 473	if (ext_depth(inode) != depth &&
 474	    !ext4_extent_block_csum_verify(inode, eh)) {
 475		error_msg = "extent tree corrupted";
 476		err = -EFSBADCRC;
 477		goto corrupted;
 478	}
 479	return 0;
 480
 481corrupted:
 482	ext4_error_inode(inode, function, line, 0,
 483			 "pblk %llu bad header/extent: %s - magic %x, "
 484			 "entries %u, max %u(%u), depth %u(%u)",
 485			 (unsigned long long) pblk, error_msg,
 486			 le16_to_cpu(eh->eh_magic),
 487			 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 488			 max, le16_to_cpu(eh->eh_depth), depth);
 
 489	return err;
 490}
 491
 492#define ext4_ext_check(inode, eh, depth, pblk)			\
 493	__ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 494
 495int ext4_ext_check_inode(struct inode *inode)
 496{
 497	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 498}
 499
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 500static struct buffer_head *
 501__read_extent_tree_block(const char *function, unsigned int line,
 502			 struct inode *inode, ext4_fsblk_t pblk, int depth,
 503			 int flags)
 504{
 505	struct buffer_head		*bh;
 506	int				err;
 
 
 507
 508	bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 
 
 
 
 509	if (unlikely(!bh))
 510		return ERR_PTR(-ENOMEM);
 511
 512	if (!bh_uptodate_or_lock(bh)) {
 513		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 514		err = bh_submit_read(bh);
 515		if (err < 0)
 516			goto errout;
 517	}
 518	if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 519		return bh;
 520	err = __ext4_ext_check(function, line, inode,
 521			       ext_block_hdr(bh), depth, pblk);
 522	if (err)
 523		goto errout;
 524	set_buffer_verified(bh);
 525	/*
 526	 * If this is a leaf block, cache all of its entries
 527	 */
 528	if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 529		struct ext4_extent_header *eh = ext_block_hdr(bh);
 530		struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 531		ext4_lblk_t prev = 0;
 532		int i;
 533
 534		for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 535			unsigned int status = EXTENT_STATUS_WRITTEN;
 536			ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 537			int len = ext4_ext_get_actual_len(ex);
 538
 539			if (prev && (prev != lblk))
 540				ext4_es_cache_extent(inode, prev,
 541						     lblk - prev, ~0,
 542						     EXTENT_STATUS_HOLE);
 543
 544			if (ext4_ext_is_unwritten(ex))
 545				status = EXTENT_STATUS_UNWRITTEN;
 546			ext4_es_cache_extent(inode, lblk, len,
 547					     ext4_ext_pblock(ex), status);
 548			prev = lblk + len;
 549		}
 550	}
 551	return bh;
 552errout:
 553	put_bh(bh);
 554	return ERR_PTR(err);
 555
 556}
 557
 558#define read_extent_tree_block(inode, pblk, depth, flags)		\
 559	__read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 560				 (depth), (flags))
 561
 562/*
 563 * This function is called to cache a file's extent information in the
 564 * extent status tree
 565 */
 566int ext4_ext_precache(struct inode *inode)
 567{
 568	struct ext4_inode_info *ei = EXT4_I(inode);
 569	struct ext4_ext_path *path = NULL;
 570	struct buffer_head *bh;
 571	int i = 0, depth, ret = 0;
 572
 573	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 574		return 0;	/* not an extent-mapped inode */
 575
 576	down_read(&ei->i_data_sem);
 577	depth = ext_depth(inode);
 578
 579	path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 
 
 
 
 
 
 580		       GFP_NOFS);
 581	if (path == NULL) {
 582		up_read(&ei->i_data_sem);
 583		return -ENOMEM;
 584	}
 585
 586	/* Don't cache anything if there are no external extent blocks */
 587	if (depth == 0)
 588		goto out;
 589	path[0].p_hdr = ext_inode_hdr(inode);
 590	ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 591	if (ret)
 592		goto out;
 593	path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 594	while (i >= 0) {
 595		/*
 596		 * If this is a leaf block or we've reached the end of
 597		 * the index block, go up
 598		 */
 599		if ((i == depth) ||
 600		    path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 601			brelse(path[i].p_bh);
 602			path[i].p_bh = NULL;
 603			i--;
 604			continue;
 605		}
 606		bh = read_extent_tree_block(inode,
 607					    ext4_idx_pblock(path[i].p_idx++),
 608					    depth - i - 1,
 609					    EXT4_EX_FORCE_CACHE);
 610		if (IS_ERR(bh)) {
 611			ret = PTR_ERR(bh);
 612			break;
 613		}
 614		i++;
 615		path[i].p_bh = bh;
 616		path[i].p_hdr = ext_block_hdr(bh);
 617		path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 618	}
 619	ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 620out:
 621	up_read(&ei->i_data_sem);
 622	ext4_ext_drop_refs(path);
 623	kfree(path);
 624	return ret;
 625}
 626
 627#ifdef EXT_DEBUG
 628static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 629{
 630	int k, l = path->p_depth;
 631
 632	ext_debug("path:");
 633	for (k = 0; k <= l; k++, path++) {
 634		if (path->p_idx) {
 635		  ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 636			    ext4_idx_pblock(path->p_idx));
 
 637		} else if (path->p_ext) {
 638			ext_debug("  %d:[%d]%d:%llu ",
 639				  le32_to_cpu(path->p_ext->ee_block),
 640				  ext4_ext_is_unwritten(path->p_ext),
 641				  ext4_ext_get_actual_len(path->p_ext),
 642				  ext4_ext_pblock(path->p_ext));
 643		} else
 644			ext_debug("  []");
 645	}
 646	ext_debug("\n");
 647}
 648
 649static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 650{
 651	int depth = ext_depth(inode);
 652	struct ext4_extent_header *eh;
 653	struct ext4_extent *ex;
 654	int i;
 655
 656	if (!path)
 657		return;
 658
 659	eh = path[depth].p_hdr;
 660	ex = EXT_FIRST_EXTENT(eh);
 661
 662	ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 663
 664	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 665		ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 666			  ext4_ext_is_unwritten(ex),
 667			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 668	}
 669	ext_debug("\n");
 670}
 671
 672static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 673			ext4_fsblk_t newblock, int level)
 674{
 675	int depth = ext_depth(inode);
 676	struct ext4_extent *ex;
 677
 678	if (depth != level) {
 679		struct ext4_extent_idx *idx;
 680		idx = path[level].p_idx;
 681		while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 682			ext_debug("%d: move %d:%llu in new index %llu\n", level,
 683					le32_to_cpu(idx->ei_block),
 684					ext4_idx_pblock(idx),
 685					newblock);
 686			idx++;
 687		}
 688
 689		return;
 690	}
 691
 692	ex = path[depth].p_ext;
 693	while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 694		ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 695				le32_to_cpu(ex->ee_block),
 696				ext4_ext_pblock(ex),
 697				ext4_ext_is_unwritten(ex),
 698				ext4_ext_get_actual_len(ex),
 699				newblock);
 700		ex++;
 701	}
 702}
 703
 704#else
 705#define ext4_ext_show_path(inode, path)
 706#define ext4_ext_show_leaf(inode, path)
 707#define ext4_ext_show_move(inode, path, newblock, level)
 708#endif
 709
 710void ext4_ext_drop_refs(struct ext4_ext_path *path)
 711{
 712	int depth, i;
 713
 714	if (!path)
 715		return;
 716	depth = path->p_depth;
 717	for (i = 0; i <= depth; i++, path++)
 718		if (path->p_bh) {
 719			brelse(path->p_bh);
 720			path->p_bh = NULL;
 721		}
 722}
 723
 724/*
 725 * ext4_ext_binsearch_idx:
 726 * binary search for the closest index of the given block
 727 * the header must be checked before calling this
 728 */
 729static void
 730ext4_ext_binsearch_idx(struct inode *inode,
 731			struct ext4_ext_path *path, ext4_lblk_t block)
 732{
 733	struct ext4_extent_header *eh = path->p_hdr;
 734	struct ext4_extent_idx *r, *l, *m;
 735
 736
 737	ext_debug("binsearch for %u(idx):  ", block);
 738
 739	l = EXT_FIRST_INDEX(eh) + 1;
 740	r = EXT_LAST_INDEX(eh);
 741	while (l <= r) {
 742		m = l + (r - l) / 2;
 
 
 
 
 743		if (block < le32_to_cpu(m->ei_block))
 744			r = m - 1;
 745		else
 746			l = m + 1;
 747		ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 748				m, le32_to_cpu(m->ei_block),
 749				r, le32_to_cpu(r->ei_block));
 750	}
 751
 752	path->p_idx = l - 1;
 753	ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 754		  ext4_idx_pblock(path->p_idx));
 755
 756#ifdef CHECK_BINSEARCH
 757	{
 758		struct ext4_extent_idx *chix, *ix;
 759		int k;
 760
 761		chix = ix = EXT_FIRST_INDEX(eh);
 762		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 763		  if (k != 0 &&
 764		      le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 765				printk(KERN_DEBUG "k=%d, ix=0x%p, "
 766				       "first=0x%p\n", k,
 767				       ix, EXT_FIRST_INDEX(eh));
 768				printk(KERN_DEBUG "%u <= %u\n",
 769				       le32_to_cpu(ix->ei_block),
 770				       le32_to_cpu(ix[-1].ei_block));
 771			}
 772			BUG_ON(k && le32_to_cpu(ix->ei_block)
 773					   <= le32_to_cpu(ix[-1].ei_block));
 774			if (block < le32_to_cpu(ix->ei_block))
 775				break;
 776			chix = ix;
 777		}
 778		BUG_ON(chix != path->p_idx);
 779	}
 780#endif
 781
 782}
 783
 784/*
 785 * ext4_ext_binsearch:
 786 * binary search for closest extent of the given block
 787 * the header must be checked before calling this
 788 */
 789static void
 790ext4_ext_binsearch(struct inode *inode,
 791		struct ext4_ext_path *path, ext4_lblk_t block)
 792{
 793	struct ext4_extent_header *eh = path->p_hdr;
 794	struct ext4_extent *r, *l, *m;
 795
 796	if (eh->eh_entries == 0) {
 797		/*
 798		 * this leaf is empty:
 799		 * we get such a leaf in split/add case
 800		 */
 801		return;
 802	}
 803
 804	ext_debug("binsearch for %u:  ", block);
 805
 806	l = EXT_FIRST_EXTENT(eh) + 1;
 807	r = EXT_LAST_EXTENT(eh);
 808
 809	while (l <= r) {
 810		m = l + (r - l) / 2;
 
 
 
 
 811		if (block < le32_to_cpu(m->ee_block))
 812			r = m - 1;
 813		else
 814			l = m + 1;
 815		ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 816				m, le32_to_cpu(m->ee_block),
 817				r, le32_to_cpu(r->ee_block));
 818	}
 819
 820	path->p_ext = l - 1;
 821	ext_debug("  -> %d:%llu:[%d]%d ",
 822			le32_to_cpu(path->p_ext->ee_block),
 823			ext4_ext_pblock(path->p_ext),
 824			ext4_ext_is_unwritten(path->p_ext),
 825			ext4_ext_get_actual_len(path->p_ext));
 826
 827#ifdef CHECK_BINSEARCH
 828	{
 829		struct ext4_extent *chex, *ex;
 830		int k;
 831
 832		chex = ex = EXT_FIRST_EXTENT(eh);
 833		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 834			BUG_ON(k && le32_to_cpu(ex->ee_block)
 835					  <= le32_to_cpu(ex[-1].ee_block));
 836			if (block < le32_to_cpu(ex->ee_block))
 837				break;
 838			chex = ex;
 839		}
 840		BUG_ON(chex != path->p_ext);
 841	}
 842#endif
 843
 844}
 845
 846int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 847{
 848	struct ext4_extent_header *eh;
 849
 850	eh = ext_inode_hdr(inode);
 851	eh->eh_depth = 0;
 852	eh->eh_entries = 0;
 853	eh->eh_magic = EXT4_EXT_MAGIC;
 854	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 
 855	ext4_mark_inode_dirty(handle, inode);
 856	return 0;
 857}
 858
 859struct ext4_ext_path *
 860ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 861		 struct ext4_ext_path **orig_path, int flags)
 862{
 863	struct ext4_extent_header *eh;
 864	struct buffer_head *bh;
 865	struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 866	short int depth, i, ppos = 0;
 867	int ret;
 
 
 
 
 868
 869	eh = ext_inode_hdr(inode);
 870	depth = ext_depth(inode);
 
 
 
 
 
 
 871
 872	if (path) {
 873		ext4_ext_drop_refs(path);
 874		if (depth > path[0].p_maxdepth) {
 875			kfree(path);
 876			*orig_path = path = NULL;
 877		}
 878	}
 879	if (!path) {
 880		/* account possible depth increase */
 881		path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 882				GFP_NOFS);
 883		if (unlikely(!path))
 884			return ERR_PTR(-ENOMEM);
 885		path[0].p_maxdepth = depth + 1;
 886	}
 887	path[0].p_hdr = eh;
 888	path[0].p_bh = NULL;
 889
 890	i = depth;
 
 
 891	/* walk through the tree */
 892	while (i) {
 893		ext_debug("depth %d: num %d, max %d\n",
 894			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 895
 896		ext4_ext_binsearch_idx(inode, path + ppos, block);
 897		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 898		path[ppos].p_depth = i;
 899		path[ppos].p_ext = NULL;
 900
 901		bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 902					    flags);
 903		if (IS_ERR(bh)) {
 904			ret = PTR_ERR(bh);
 905			goto err;
 906		}
 907
 908		eh = ext_block_hdr(bh);
 909		ppos++;
 910		if (unlikely(ppos > depth)) {
 911			put_bh(bh);
 912			EXT4_ERROR_INODE(inode,
 913					 "ppos %d > depth %d", ppos, depth);
 914			ret = -EFSCORRUPTED;
 915			goto err;
 916		}
 917		path[ppos].p_bh = bh;
 918		path[ppos].p_hdr = eh;
 919	}
 920
 921	path[ppos].p_depth = i;
 922	path[ppos].p_ext = NULL;
 923	path[ppos].p_idx = NULL;
 924
 925	/* find extent */
 926	ext4_ext_binsearch(inode, path + ppos, block);
 927	/* if not an empty leaf */
 928	if (path[ppos].p_ext)
 929		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 930
 931	ext4_ext_show_path(inode, path);
 932
 933	return path;
 934
 935err:
 936	ext4_ext_drop_refs(path);
 937	kfree(path);
 938	if (orig_path)
 939		*orig_path = NULL;
 940	return ERR_PTR(ret);
 941}
 942
 943/*
 944 * ext4_ext_insert_index:
 945 * insert new index [@logical;@ptr] into the block at @curp;
 946 * check where to insert: before @curp or after @curp
 947 */
 948static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 949				 struct ext4_ext_path *curp,
 950				 int logical, ext4_fsblk_t ptr)
 951{
 952	struct ext4_extent_idx *ix;
 953	int len, err;
 954
 955	err = ext4_ext_get_access(handle, inode, curp);
 956	if (err)
 957		return err;
 958
 959	if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 960		EXT4_ERROR_INODE(inode,
 961				 "logical %d == ei_block %d!",
 962				 logical, le32_to_cpu(curp->p_idx->ei_block));
 963		return -EFSCORRUPTED;
 964	}
 965
 966	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 967			     >= le16_to_cpu(curp->p_hdr->eh_max))) {
 968		EXT4_ERROR_INODE(inode,
 969				 "eh_entries %d >= eh_max %d!",
 970				 le16_to_cpu(curp->p_hdr->eh_entries),
 971				 le16_to_cpu(curp->p_hdr->eh_max));
 972		return -EFSCORRUPTED;
 973	}
 974
 975	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 976		/* insert after */
 977		ext_debug("insert new index %d after: %llu\n", logical, ptr);
 
 978		ix = curp->p_idx + 1;
 979	} else {
 980		/* insert before */
 981		ext_debug("insert new index %d before: %llu\n", logical, ptr);
 
 982		ix = curp->p_idx;
 983	}
 984
 
 
 
 
 
 985	len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 986	BUG_ON(len < 0);
 987	if (len > 0) {
 988		ext_debug("insert new index %d: "
 989				"move %d indices from 0x%p to 0x%p\n",
 990				logical, len, ix, ix + 1);
 991		memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 992	}
 993
 994	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 995		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 996		return -EFSCORRUPTED;
 997	}
 998
 999	ix->ei_block = cpu_to_le32(logical);
1000	ext4_idx_store_pblock(ix, ptr);
1001	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1002
1003	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1004		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1005		return -EFSCORRUPTED;
1006	}
1007
1008	err = ext4_ext_dirty(handle, inode, curp);
1009	ext4_std_error(inode->i_sb, err);
1010
1011	return err;
1012}
1013
1014/*
1015 * ext4_ext_split:
1016 * inserts new subtree into the path, using free index entry
1017 * at depth @at:
1018 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1019 * - makes decision where to split
1020 * - moves remaining extents and index entries (right to the split point)
1021 *   into the newly allocated blocks
1022 * - initializes subtree
1023 */
1024static int ext4_ext_split(handle_t *handle, struct inode *inode,
1025			  unsigned int flags,
1026			  struct ext4_ext_path *path,
1027			  struct ext4_extent *newext, int at)
1028{
1029	struct buffer_head *bh = NULL;
1030	int depth = ext_depth(inode);
1031	struct ext4_extent_header *neh;
1032	struct ext4_extent_idx *fidx;
1033	int i = at, k, m, a;
1034	ext4_fsblk_t newblock, oldblock;
1035	__le32 border;
1036	ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
 
1037	int err = 0;
 
 
 
 
1038
1039	/* make decision: where to split? */
1040	/* FIXME: now decision is simplest: at current extent */
1041
1042	/* if current leaf will be split, then we should use
1043	 * border from split point */
1044	if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1045		EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1046		return -EFSCORRUPTED;
1047	}
1048	if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1049		border = path[depth].p_ext[1].ee_block;
1050		ext_debug("leaf will be split."
1051				" next leaf starts at %d\n",
1052				  le32_to_cpu(border));
1053	} else {
1054		border = newext->ee_block;
1055		ext_debug("leaf will be added."
1056				" next leaf starts at %d\n",
1057				le32_to_cpu(border));
1058	}
1059
1060	/*
1061	 * If error occurs, then we break processing
1062	 * and mark filesystem read-only. index won't
1063	 * be inserted and tree will be in consistent
1064	 * state. Next mount will repair buffers too.
1065	 */
1066
1067	/*
1068	 * Get array to track all allocated blocks.
1069	 * We need this to handle errors and free blocks
1070	 * upon them.
1071	 */
1072	ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1073	if (!ablocks)
1074		return -ENOMEM;
1075
1076	/* allocate all needed blocks */
1077	ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1078	for (a = 0; a < depth - at; a++) {
1079		newblock = ext4_ext_new_meta_block(handle, inode, path,
1080						   newext, &err, flags);
1081		if (newblock == 0)
1082			goto cleanup;
1083		ablocks[a] = newblock;
1084	}
1085
1086	/* initialize new leaf */
1087	newblock = ablocks[--a];
1088	if (unlikely(newblock == 0)) {
1089		EXT4_ERROR_INODE(inode, "newblock == 0!");
1090		err = -EFSCORRUPTED;
1091		goto cleanup;
1092	}
1093	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1094	if (unlikely(!bh)) {
1095		err = -ENOMEM;
1096		goto cleanup;
1097	}
1098	lock_buffer(bh);
1099
1100	err = ext4_journal_get_create_access(handle, bh);
 
1101	if (err)
1102		goto cleanup;
1103
1104	neh = ext_block_hdr(bh);
1105	neh->eh_entries = 0;
1106	neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1107	neh->eh_magic = EXT4_EXT_MAGIC;
1108	neh->eh_depth = 0;
 
1109
1110	/* move remainder of path[depth] to the new leaf */
1111	if (unlikely(path[depth].p_hdr->eh_entries !=
1112		     path[depth].p_hdr->eh_max)) {
1113		EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1114				 path[depth].p_hdr->eh_entries,
1115				 path[depth].p_hdr->eh_max);
1116		err = -EFSCORRUPTED;
1117		goto cleanup;
1118	}
1119	/* start copy from next extent */
1120	m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1121	ext4_ext_show_move(inode, path, newblock, depth);
1122	if (m) {
1123		struct ext4_extent *ex;
1124		ex = EXT_FIRST_EXTENT(neh);
1125		memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1126		le16_add_cpu(&neh->eh_entries, m);
1127	}
1128
 
 
 
 
1129	ext4_extent_block_csum_set(inode, neh);
1130	set_buffer_uptodate(bh);
1131	unlock_buffer(bh);
1132
1133	err = ext4_handle_dirty_metadata(handle, inode, bh);
1134	if (err)
1135		goto cleanup;
1136	brelse(bh);
1137	bh = NULL;
1138
1139	/* correct old leaf */
1140	if (m) {
1141		err = ext4_ext_get_access(handle, inode, path + depth);
1142		if (err)
1143			goto cleanup;
1144		le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1145		err = ext4_ext_dirty(handle, inode, path + depth);
1146		if (err)
1147			goto cleanup;
1148
1149	}
1150
1151	/* create intermediate indexes */
1152	k = depth - at - 1;
1153	if (unlikely(k < 0)) {
1154		EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1155		err = -EFSCORRUPTED;
1156		goto cleanup;
1157	}
1158	if (k)
1159		ext_debug("create %d intermediate indices\n", k);
1160	/* insert new index into current index block */
1161	/* current depth stored in i var */
1162	i = depth - 1;
1163	while (k--) {
1164		oldblock = newblock;
1165		newblock = ablocks[--a];
1166		bh = sb_getblk(inode->i_sb, newblock);
1167		if (unlikely(!bh)) {
1168			err = -ENOMEM;
1169			goto cleanup;
1170		}
1171		lock_buffer(bh);
1172
1173		err = ext4_journal_get_create_access(handle, bh);
 
1174		if (err)
1175			goto cleanup;
1176
1177		neh = ext_block_hdr(bh);
1178		neh->eh_entries = cpu_to_le16(1);
1179		neh->eh_magic = EXT4_EXT_MAGIC;
1180		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1181		neh->eh_depth = cpu_to_le16(depth - i);
 
1182		fidx = EXT_FIRST_INDEX(neh);
1183		fidx->ei_block = border;
1184		ext4_idx_store_pblock(fidx, oldblock);
1185
1186		ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1187				i, newblock, le32_to_cpu(border), oldblock);
1188
1189		/* move remainder of path[i] to the new index block */
1190		if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1191					EXT_LAST_INDEX(path[i].p_hdr))) {
1192			EXT4_ERROR_INODE(inode,
1193					 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1194					 le32_to_cpu(path[i].p_ext->ee_block));
1195			err = -EFSCORRUPTED;
1196			goto cleanup;
1197		}
1198		/* start copy indexes */
1199		m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1200		ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1201				EXT_MAX_INDEX(path[i].p_hdr));
1202		ext4_ext_show_move(inode, path, newblock, i);
1203		if (m) {
1204			memmove(++fidx, path[i].p_idx,
1205				sizeof(struct ext4_extent_idx) * m);
1206			le16_add_cpu(&neh->eh_entries, m);
1207		}
 
 
 
 
 
1208		ext4_extent_block_csum_set(inode, neh);
1209		set_buffer_uptodate(bh);
1210		unlock_buffer(bh);
1211
1212		err = ext4_handle_dirty_metadata(handle, inode, bh);
1213		if (err)
1214			goto cleanup;
1215		brelse(bh);
1216		bh = NULL;
1217
1218		/* correct old index */
1219		if (m) {
1220			err = ext4_ext_get_access(handle, inode, path + i);
1221			if (err)
1222				goto cleanup;
1223			le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1224			err = ext4_ext_dirty(handle, inode, path + i);
1225			if (err)
1226				goto cleanup;
1227		}
1228
1229		i--;
1230	}
1231
1232	/* insert new index */
1233	err = ext4_ext_insert_index(handle, inode, path + at,
1234				    le32_to_cpu(border), newblock);
1235
1236cleanup:
1237	if (bh) {
1238		if (buffer_locked(bh))
1239			unlock_buffer(bh);
1240		brelse(bh);
1241	}
1242
1243	if (err) {
1244		/* free all allocated blocks in error case */
1245		for (i = 0; i < depth; i++) {
1246			if (!ablocks[i])
1247				continue;
1248			ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1249					 EXT4_FREE_BLOCKS_METADATA);
1250		}
1251	}
1252	kfree(ablocks);
1253
1254	return err;
1255}
1256
1257/*
1258 * ext4_ext_grow_indepth:
1259 * implements tree growing procedure:
1260 * - allocates new block
1261 * - moves top-level data (index block or leaf) into the new block
1262 * - initializes new top-level, creating index that points to the
1263 *   just created block
1264 */
1265static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1266				 unsigned int flags)
1267{
1268	struct ext4_extent_header *neh;
1269	struct buffer_head *bh;
1270	ext4_fsblk_t newblock, goal = 0;
1271	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1272	int err = 0;
 
1273
1274	/* Try to prepend new index to old one */
1275	if (ext_depth(inode))
1276		goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1277	if (goal > le32_to_cpu(es->s_first_data_block)) {
1278		flags |= EXT4_MB_HINT_TRY_GOAL;
1279		goal--;
1280	} else
1281		goal = ext4_inode_to_goal_block(inode);
1282	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1283					NULL, &err);
1284	if (newblock == 0)
1285		return err;
1286
1287	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1288	if (unlikely(!bh))
1289		return -ENOMEM;
1290	lock_buffer(bh);
1291
1292	err = ext4_journal_get_create_access(handle, bh);
 
1293	if (err) {
1294		unlock_buffer(bh);
1295		goto out;
1296	}
1297
 
1298	/* move top-level index/leaf into new block */
1299	memmove(bh->b_data, EXT4_I(inode)->i_data,
1300		sizeof(EXT4_I(inode)->i_data));
 
1301
1302	/* set size of new block */
1303	neh = ext_block_hdr(bh);
1304	/* old root could have indexes or leaves
1305	 * so calculate e_max right way */
1306	if (ext_depth(inode))
1307		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1308	else
1309		neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1310	neh->eh_magic = EXT4_EXT_MAGIC;
1311	ext4_extent_block_csum_set(inode, neh);
1312	set_buffer_uptodate(bh);
 
1313	unlock_buffer(bh);
1314
1315	err = ext4_handle_dirty_metadata(handle, inode, bh);
1316	if (err)
1317		goto out;
1318
1319	/* Update top-level index: num,max,pointer */
1320	neh = ext_inode_hdr(inode);
1321	neh->eh_entries = cpu_to_le16(1);
1322	ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1323	if (neh->eh_depth == 0) {
1324		/* Root extent block becomes index block */
1325		neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1326		EXT_FIRST_INDEX(neh)->ei_block =
1327			EXT_FIRST_EXTENT(neh)->ee_block;
1328	}
1329	ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1330		  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1331		  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1332		  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1333
1334	le16_add_cpu(&neh->eh_depth, 1);
1335	ext4_mark_inode_dirty(handle, inode);
1336out:
1337	brelse(bh);
1338
1339	return err;
1340}
1341
1342/*
1343 * ext4_ext_create_new_leaf:
1344 * finds empty index and adds new leaf.
1345 * if no free index is found, then it requests in-depth growing.
1346 */
1347static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1348				    unsigned int mb_flags,
1349				    unsigned int gb_flags,
1350				    struct ext4_ext_path **ppath,
1351				    struct ext4_extent *newext)
1352{
1353	struct ext4_ext_path *path = *ppath;
1354	struct ext4_ext_path *curp;
1355	int depth, i, err = 0;
1356
1357repeat:
1358	i = depth = ext_depth(inode);
1359
1360	/* walk up to the tree and look for free index entry */
1361	curp = path + depth;
1362	while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1363		i--;
1364		curp--;
1365	}
1366
1367	/* we use already allocated block for index block,
1368	 * so subsequent data blocks should be contiguous */
1369	if (EXT_HAS_FREE_INDEX(curp)) {
1370		/* if we found index with free entry, then use that
1371		 * entry: create all needed subtree and add new leaf */
1372		err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1373		if (err)
1374			goto out;
1375
1376		/* refill path */
1377		path = ext4_find_extent(inode,
1378				    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1379				    ppath, gb_flags);
1380		if (IS_ERR(path))
1381			err = PTR_ERR(path);
1382	} else {
1383		/* tree is full, time to grow in depth */
1384		err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1385		if (err)
1386			goto out;
1387
1388		/* refill path */
1389		path = ext4_find_extent(inode,
1390				   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1391				    ppath, gb_flags);
1392		if (IS_ERR(path)) {
1393			err = PTR_ERR(path);
1394			goto out;
1395		}
1396
1397		/*
1398		 * only first (depth 0 -> 1) produces free space;
1399		 * in all other cases we have to split the grown tree
1400		 */
1401		depth = ext_depth(inode);
1402		if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1403			/* now we need to split */
1404			goto repeat;
1405		}
1406	}
1407
1408out:
1409	return err;
1410}
1411
1412/*
1413 * search the closest allocated block to the left for *logical
1414 * and returns it at @logical + it's physical address at @phys
1415 * if *logical is the smallest allocated block, the function
1416 * returns 0 at @phys
1417 * return value contains 0 (success) or error code
1418 */
1419static int ext4_ext_search_left(struct inode *inode,
1420				struct ext4_ext_path *path,
1421				ext4_lblk_t *logical, ext4_fsblk_t *phys)
1422{
1423	struct ext4_extent_idx *ix;
1424	struct ext4_extent *ex;
1425	int depth, ee_len;
1426
1427	if (unlikely(path == NULL)) {
1428		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1429		return -EFSCORRUPTED;
1430	}
1431	depth = path->p_depth;
1432	*phys = 0;
1433
1434	if (depth == 0 && path->p_ext == NULL)
1435		return 0;
1436
1437	/* usually extent in the path covers blocks smaller
1438	 * then *logical, but it can be that extent is the
1439	 * first one in the file */
1440
1441	ex = path[depth].p_ext;
1442	ee_len = ext4_ext_get_actual_len(ex);
1443	if (*logical < le32_to_cpu(ex->ee_block)) {
1444		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1445			EXT4_ERROR_INODE(inode,
1446					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1447					 *logical, le32_to_cpu(ex->ee_block));
1448			return -EFSCORRUPTED;
1449		}
1450		while (--depth >= 0) {
1451			ix = path[depth].p_idx;
1452			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1453				EXT4_ERROR_INODE(inode,
1454				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1455				  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1456				  EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1457		le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1458				  depth);
1459				return -EFSCORRUPTED;
1460			}
1461		}
1462		return 0;
1463	}
1464
1465	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1466		EXT4_ERROR_INODE(inode,
1467				 "logical %d < ee_block %d + ee_len %d!",
1468				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1469		return -EFSCORRUPTED;
1470	}
1471
1472	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1473	*phys = ext4_ext_pblock(ex) + ee_len - 1;
1474	return 0;
1475}
1476
1477/*
1478 * search the closest allocated block to the right for *logical
1479 * and returns it at @logical + it's physical address at @phys
1480 * if *logical is the largest allocated block, the function
1481 * returns 0 at @phys
1482 * return value contains 0 (success) or error code
1483 */
1484static int ext4_ext_search_right(struct inode *inode,
1485				 struct ext4_ext_path *path,
1486				 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1487				 struct ext4_extent **ret_ex)
1488{
1489	struct buffer_head *bh = NULL;
1490	struct ext4_extent_header *eh;
1491	struct ext4_extent_idx *ix;
1492	struct ext4_extent *ex;
1493	ext4_fsblk_t block;
1494	int depth;	/* Note, NOT eh_depth; depth from top of tree */
1495	int ee_len;
1496
1497	if (unlikely(path == NULL)) {
1498		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1499		return -EFSCORRUPTED;
1500	}
1501	depth = path->p_depth;
1502	*phys = 0;
1503
1504	if (depth == 0 && path->p_ext == NULL)
1505		return 0;
1506
1507	/* usually extent in the path covers blocks smaller
1508	 * then *logical, but it can be that extent is the
1509	 * first one in the file */
1510
1511	ex = path[depth].p_ext;
1512	ee_len = ext4_ext_get_actual_len(ex);
1513	if (*logical < le32_to_cpu(ex->ee_block)) {
1514		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1515			EXT4_ERROR_INODE(inode,
1516					 "first_extent(path[%d].p_hdr) != ex",
1517					 depth);
1518			return -EFSCORRUPTED;
1519		}
1520		while (--depth >= 0) {
1521			ix = path[depth].p_idx;
1522			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1523				EXT4_ERROR_INODE(inode,
1524						 "ix != EXT_FIRST_INDEX *logical %d!",
1525						 *logical);
1526				return -EFSCORRUPTED;
1527			}
1528		}
1529		goto found_extent;
1530	}
1531
1532	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1533		EXT4_ERROR_INODE(inode,
1534				 "logical %d < ee_block %d + ee_len %d!",
1535				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1536		return -EFSCORRUPTED;
1537	}
1538
1539	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1540		/* next allocated block in this leaf */
1541		ex++;
1542		goto found_extent;
1543	}
1544
1545	/* go up and search for index to the right */
1546	while (--depth >= 0) {
1547		ix = path[depth].p_idx;
1548		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1549			goto got_index;
1550	}
1551
1552	/* we've gone up to the root and found no index to the right */
1553	return 0;
1554
1555got_index:
1556	/* we've found index to the right, let's
1557	 * follow it and find the closest allocated
1558	 * block to the right */
1559	ix++;
1560	block = ext4_idx_pblock(ix);
1561	while (++depth < path->p_depth) {
1562		/* subtract from p_depth to get proper eh_depth */
1563		bh = read_extent_tree_block(inode, block,
1564					    path->p_depth - depth, 0);
1565		if (IS_ERR(bh))
1566			return PTR_ERR(bh);
1567		eh = ext_block_hdr(bh);
1568		ix = EXT_FIRST_INDEX(eh);
1569		block = ext4_idx_pblock(ix);
1570		put_bh(bh);
1571	}
1572
1573	bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1574	if (IS_ERR(bh))
1575		return PTR_ERR(bh);
1576	eh = ext_block_hdr(bh);
1577	ex = EXT_FIRST_EXTENT(eh);
1578found_extent:
1579	*logical = le32_to_cpu(ex->ee_block);
1580	*phys = ext4_ext_pblock(ex);
1581	*ret_ex = ex;
 
1582	if (bh)
1583		put_bh(bh);
1584	return 0;
1585}
1586
1587/*
1588 * ext4_ext_next_allocated_block:
1589 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1590 * NOTE: it considers block number from index entry as
1591 * allocated block. Thus, index entries have to be consistent
1592 * with leaves.
1593 */
1594ext4_lblk_t
1595ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1596{
1597	int depth;
1598
1599	BUG_ON(path == NULL);
1600	depth = path->p_depth;
1601
1602	if (depth == 0 && path->p_ext == NULL)
1603		return EXT_MAX_BLOCKS;
1604
1605	while (depth >= 0) {
 
 
1606		if (depth == path->p_depth) {
1607			/* leaf */
1608			if (path[depth].p_ext &&
1609				path[depth].p_ext !=
1610					EXT_LAST_EXTENT(path[depth].p_hdr))
1611			  return le32_to_cpu(path[depth].p_ext[1].ee_block);
1612		} else {
1613			/* index */
1614			if (path[depth].p_idx !=
1615					EXT_LAST_INDEX(path[depth].p_hdr))
1616			  return le32_to_cpu(path[depth].p_idx[1].ei_block);
1617		}
1618		depth--;
1619	}
1620
1621	return EXT_MAX_BLOCKS;
1622}
1623
1624/*
1625 * ext4_ext_next_leaf_block:
1626 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1627 */
1628static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1629{
1630	int depth;
1631
1632	BUG_ON(path == NULL);
1633	depth = path->p_depth;
1634
1635	/* zero-tree has no leaf blocks at all */
1636	if (depth == 0)
1637		return EXT_MAX_BLOCKS;
1638
1639	/* go to index block */
1640	depth--;
1641
1642	while (depth >= 0) {
1643		if (path[depth].p_idx !=
1644				EXT_LAST_INDEX(path[depth].p_hdr))
1645			return (ext4_lblk_t)
1646				le32_to_cpu(path[depth].p_idx[1].ei_block);
1647		depth--;
1648	}
1649
1650	return EXT_MAX_BLOCKS;
1651}
1652
1653/*
1654 * ext4_ext_correct_indexes:
1655 * if leaf gets modified and modified extent is first in the leaf,
1656 * then we have to correct all indexes above.
1657 * TODO: do we need to correct tree in all cases?
1658 */
1659static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1660				struct ext4_ext_path *path)
1661{
1662	struct ext4_extent_header *eh;
1663	int depth = ext_depth(inode);
1664	struct ext4_extent *ex;
1665	__le32 border;
1666	int k, err = 0;
1667
1668	eh = path[depth].p_hdr;
1669	ex = path[depth].p_ext;
1670
1671	if (unlikely(ex == NULL || eh == NULL)) {
1672		EXT4_ERROR_INODE(inode,
1673				 "ex %p == NULL or eh %p == NULL", ex, eh);
1674		return -EFSCORRUPTED;
1675	}
1676
1677	if (depth == 0) {
1678		/* there is no tree at all */
1679		return 0;
1680	}
1681
1682	if (ex != EXT_FIRST_EXTENT(eh)) {
1683		/* we correct tree if first leaf got modified only */
1684		return 0;
1685	}
1686
1687	/*
1688	 * TODO: we need correction if border is smaller than current one
1689	 */
1690	k = depth - 1;
1691	border = path[depth].p_ext->ee_block;
1692	err = ext4_ext_get_access(handle, inode, path + k);
1693	if (err)
1694		return err;
1695	path[k].p_idx->ei_block = border;
1696	err = ext4_ext_dirty(handle, inode, path + k);
1697	if (err)
1698		return err;
1699
1700	while (k--) {
1701		/* change all left-side indexes */
1702		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1703			break;
1704		err = ext4_ext_get_access(handle, inode, path + k);
1705		if (err)
1706			break;
1707		path[k].p_idx->ei_block = border;
1708		err = ext4_ext_dirty(handle, inode, path + k);
1709		if (err)
1710			break;
1711	}
1712
1713	return err;
1714}
1715
1716int
1717ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1718				struct ext4_extent *ex2)
1719{
1720	unsigned short ext1_ee_len, ext2_ee_len;
1721
1722	if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1723		return 0;
1724
1725	ext1_ee_len = ext4_ext_get_actual_len(ex1);
1726	ext2_ee_len = ext4_ext_get_actual_len(ex2);
1727
1728	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1729			le32_to_cpu(ex2->ee_block))
1730		return 0;
1731
1732	/*
1733	 * To allow future support for preallocated extents to be added
1734	 * as an RO_COMPAT feature, refuse to merge to extents if
1735	 * this can result in the top bit of ee_len being set.
1736	 */
1737	if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1738		return 0;
1739	/*
1740	 * The check for IO to unwritten extent is somewhat racy as we
1741	 * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1742	 * dropping i_data_sem. But reserved blocks should save us in that
1743	 * case.
1744	 */
1745	if (ext4_ext_is_unwritten(ex1) &&
1746	    (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1747	     atomic_read(&EXT4_I(inode)->i_unwritten) ||
1748	     (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1749		return 0;
1750#ifdef AGGRESSIVE_TEST
1751	if (ext1_ee_len >= 4)
1752		return 0;
1753#endif
1754
1755	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1756		return 1;
1757	return 0;
1758}
1759
1760/*
1761 * This function tries to merge the "ex" extent to the next extent in the tree.
1762 * It always tries to merge towards right. If you want to merge towards
1763 * left, pass "ex - 1" as argument instead of "ex".
1764 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1765 * 1 if they got merged.
1766 */
1767static int ext4_ext_try_to_merge_right(struct inode *inode,
1768				 struct ext4_ext_path *path,
1769				 struct ext4_extent *ex)
1770{
1771	struct ext4_extent_header *eh;
1772	unsigned int depth, len;
1773	int merge_done = 0, unwritten;
1774
1775	depth = ext_depth(inode);
1776	BUG_ON(path[depth].p_hdr == NULL);
1777	eh = path[depth].p_hdr;
1778
1779	while (ex < EXT_LAST_EXTENT(eh)) {
1780		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1781			break;
1782		/* merge with next extent! */
1783		unwritten = ext4_ext_is_unwritten(ex);
1784		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1785				+ ext4_ext_get_actual_len(ex + 1));
1786		if (unwritten)
1787			ext4_ext_mark_unwritten(ex);
1788
1789		if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1790			len = (EXT_LAST_EXTENT(eh) - ex - 1)
1791				* sizeof(struct ext4_extent);
1792			memmove(ex + 1, ex + 2, len);
1793		}
1794		le16_add_cpu(&eh->eh_entries, -1);
1795		merge_done = 1;
1796		WARN_ON(eh->eh_entries == 0);
1797		if (!eh->eh_entries)
1798			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1799	}
1800
1801	return merge_done;
1802}
1803
1804/*
1805 * This function does a very simple check to see if we can collapse
1806 * an extent tree with a single extent tree leaf block into the inode.
1807 */
1808static void ext4_ext_try_to_merge_up(handle_t *handle,
1809				     struct inode *inode,
1810				     struct ext4_ext_path *path)
1811{
1812	size_t s;
1813	unsigned max_root = ext4_ext_space_root(inode, 0);
1814	ext4_fsblk_t blk;
1815
1816	if ((path[0].p_depth != 1) ||
1817	    (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1818	    (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1819		return;
1820
1821	/*
1822	 * We need to modify the block allocation bitmap and the block
1823	 * group descriptor to release the extent tree block.  If we
1824	 * can't get the journal credits, give up.
1825	 */
1826	if (ext4_journal_extend(handle, 2))
 
1827		return;
1828
1829	/*
1830	 * Copy the extent data up to the inode
1831	 */
1832	blk = ext4_idx_pblock(path[0].p_idx);
1833	s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1834		sizeof(struct ext4_extent_idx);
1835	s += sizeof(struct ext4_extent_header);
1836
1837	path[1].p_maxdepth = path[0].p_maxdepth;
1838	memcpy(path[0].p_hdr, path[1].p_hdr, s);
1839	path[0].p_depth = 0;
1840	path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1841		(path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1842	path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1843
1844	brelse(path[1].p_bh);
1845	ext4_free_blocks(handle, inode, NULL, blk, 1,
1846			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1847}
1848
1849/*
1850 * This function tries to merge the @ex extent to neighbours in the tree.
1851 * return 1 if merge left else 0.
1852 */
1853static void ext4_ext_try_to_merge(handle_t *handle,
1854				  struct inode *inode,
1855				  struct ext4_ext_path *path,
1856				  struct ext4_extent *ex) {
 
1857	struct ext4_extent_header *eh;
1858	unsigned int depth;
1859	int merge_done = 0;
1860
1861	depth = ext_depth(inode);
1862	BUG_ON(path[depth].p_hdr == NULL);
1863	eh = path[depth].p_hdr;
1864
1865	if (ex > EXT_FIRST_EXTENT(eh))
1866		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1867
1868	if (!merge_done)
1869		(void) ext4_ext_try_to_merge_right(inode, path, ex);
1870
1871	ext4_ext_try_to_merge_up(handle, inode, path);
1872}
1873
1874/*
1875 * check if a portion of the "newext" extent overlaps with an
1876 * existing extent.
1877 *
1878 * If there is an overlap discovered, it updates the length of the newext
1879 * such that there will be no overlap, and then returns 1.
1880 * If there is no overlap found, it returns 0.
1881 */
1882static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1883					   struct inode *inode,
1884					   struct ext4_extent *newext,
1885					   struct ext4_ext_path *path)
1886{
1887	ext4_lblk_t b1, b2;
1888	unsigned int depth, len1;
1889	unsigned int ret = 0;
1890
1891	b1 = le32_to_cpu(newext->ee_block);
1892	len1 = ext4_ext_get_actual_len(newext);
1893	depth = ext_depth(inode);
1894	if (!path[depth].p_ext)
1895		goto out;
1896	b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1897
1898	/*
1899	 * get the next allocated block if the extent in the path
1900	 * is before the requested block(s)
1901	 */
1902	if (b2 < b1) {
1903		b2 = ext4_ext_next_allocated_block(path);
1904		if (b2 == EXT_MAX_BLOCKS)
1905			goto out;
1906		b2 = EXT4_LBLK_CMASK(sbi, b2);
1907	}
1908
1909	/* check for wrap through zero on extent logical start block*/
1910	if (b1 + len1 < b1) {
1911		len1 = EXT_MAX_BLOCKS - b1;
1912		newext->ee_len = cpu_to_le16(len1);
1913		ret = 1;
1914	}
1915
1916	/* check for overlap */
1917	if (b1 + len1 > b2) {
1918		newext->ee_len = cpu_to_le16(b2 - b1);
1919		ret = 1;
1920	}
1921out:
1922	return ret;
1923}
1924
1925/*
1926 * ext4_ext_insert_extent:
1927 * tries to merge requsted extent into the existing extent or
1928 * inserts requested extent as new one into the tree,
1929 * creating new leaf in the no-space case.
1930 */
1931int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1932				struct ext4_ext_path **ppath,
1933				struct ext4_extent *newext, int gb_flags)
1934{
1935	struct ext4_ext_path *path = *ppath;
1936	struct ext4_extent_header *eh;
1937	struct ext4_extent *ex, *fex;
1938	struct ext4_extent *nearex; /* nearest extent */
1939	struct ext4_ext_path *npath = NULL;
1940	int depth, len, err;
1941	ext4_lblk_t next;
1942	int mb_flags = 0, unwritten;
1943
1944	if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1945		mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1946	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1947		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1948		return -EFSCORRUPTED;
1949	}
1950	depth = ext_depth(inode);
1951	ex = path[depth].p_ext;
1952	eh = path[depth].p_hdr;
1953	if (unlikely(path[depth].p_hdr == NULL)) {
1954		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1955		return -EFSCORRUPTED;
1956	}
1957
1958	/* try to insert block into found extent and return */
1959	if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1960
1961		/*
1962		 * Try to see whether we should rather test the extent on
1963		 * right from ex, or from the left of ex. This is because
1964		 * ext4_find_extent() can return either extent on the
1965		 * left, or on the right from the searched position. This
1966		 * will make merging more effective.
1967		 */
1968		if (ex < EXT_LAST_EXTENT(eh) &&
1969		    (le32_to_cpu(ex->ee_block) +
1970		    ext4_ext_get_actual_len(ex) <
1971		    le32_to_cpu(newext->ee_block))) {
1972			ex += 1;
1973			goto prepend;
1974		} else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1975			   (le32_to_cpu(newext->ee_block) +
1976			   ext4_ext_get_actual_len(newext) <
1977			   le32_to_cpu(ex->ee_block)))
1978			ex -= 1;
1979
1980		/* Try to append newex to the ex */
1981		if (ext4_can_extents_be_merged(inode, ex, newext)) {
1982			ext_debug("append [%d]%d block to %u:[%d]%d"
1983				  "(from %llu)\n",
1984				  ext4_ext_is_unwritten(newext),
1985				  ext4_ext_get_actual_len(newext),
1986				  le32_to_cpu(ex->ee_block),
1987				  ext4_ext_is_unwritten(ex),
1988				  ext4_ext_get_actual_len(ex),
1989				  ext4_ext_pblock(ex));
1990			err = ext4_ext_get_access(handle, inode,
1991						  path + depth);
1992			if (err)
1993				return err;
1994			unwritten = ext4_ext_is_unwritten(ex);
1995			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1996					+ ext4_ext_get_actual_len(newext));
1997			if (unwritten)
1998				ext4_ext_mark_unwritten(ex);
1999			eh = path[depth].p_hdr;
2000			nearex = ex;
2001			goto merge;
2002		}
2003
2004prepend:
2005		/* Try to prepend newex to the ex */
2006		if (ext4_can_extents_be_merged(inode, newext, ex)) {
2007			ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2008				  "(from %llu)\n",
2009				  le32_to_cpu(newext->ee_block),
2010				  ext4_ext_is_unwritten(newext),
2011				  ext4_ext_get_actual_len(newext),
2012				  le32_to_cpu(ex->ee_block),
2013				  ext4_ext_is_unwritten(ex),
2014				  ext4_ext_get_actual_len(ex),
2015				  ext4_ext_pblock(ex));
2016			err = ext4_ext_get_access(handle, inode,
2017						  path + depth);
2018			if (err)
2019				return err;
2020
2021			unwritten = ext4_ext_is_unwritten(ex);
2022			ex->ee_block = newext->ee_block;
2023			ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2024			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2025					+ ext4_ext_get_actual_len(newext));
2026			if (unwritten)
2027				ext4_ext_mark_unwritten(ex);
2028			eh = path[depth].p_hdr;
2029			nearex = ex;
2030			goto merge;
2031		}
2032	}
2033
2034	depth = ext_depth(inode);
2035	eh = path[depth].p_hdr;
2036	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2037		goto has_space;
2038
2039	/* probably next leaf has space for us? */
2040	fex = EXT_LAST_EXTENT(eh);
2041	next = EXT_MAX_BLOCKS;
2042	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2043		next = ext4_ext_next_leaf_block(path);
2044	if (next != EXT_MAX_BLOCKS) {
2045		ext_debug("next leaf block - %u\n", next);
2046		BUG_ON(npath != NULL);
2047		npath = ext4_find_extent(inode, next, NULL, 0);
2048		if (IS_ERR(npath))
2049			return PTR_ERR(npath);
2050		BUG_ON(npath->p_depth != path->p_depth);
2051		eh = npath[depth].p_hdr;
2052		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2053			ext_debug("next leaf isn't full(%d)\n",
2054				  le16_to_cpu(eh->eh_entries));
2055			path = npath;
2056			goto has_space;
2057		}
2058		ext_debug("next leaf has no free space(%d,%d)\n",
2059			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2060	}
2061
2062	/*
2063	 * There is no free space in the found leaf.
2064	 * We're gonna add a new leaf in the tree.
2065	 */
2066	if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2067		mb_flags |= EXT4_MB_USE_RESERVED;
2068	err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2069				       ppath, newext);
2070	if (err)
2071		goto cleanup;
2072	depth = ext_depth(inode);
2073	eh = path[depth].p_hdr;
2074
2075has_space:
2076	nearex = path[depth].p_ext;
2077
2078	err = ext4_ext_get_access(handle, inode, path + depth);
2079	if (err)
2080		goto cleanup;
2081
2082	if (!nearex) {
2083		/* there is no extent in this leaf, create first one */
2084		ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2085				le32_to_cpu(newext->ee_block),
2086				ext4_ext_pblock(newext),
2087				ext4_ext_is_unwritten(newext),
2088				ext4_ext_get_actual_len(newext));
2089		nearex = EXT_FIRST_EXTENT(eh);
2090	} else {
2091		if (le32_to_cpu(newext->ee_block)
2092			   > le32_to_cpu(nearex->ee_block)) {
2093			/* Insert after */
2094			ext_debug("insert %u:%llu:[%d]%d before: "
2095					"nearest %p\n",
2096					le32_to_cpu(newext->ee_block),
2097					ext4_ext_pblock(newext),
2098					ext4_ext_is_unwritten(newext),
2099					ext4_ext_get_actual_len(newext),
2100					nearex);
2101			nearex++;
2102		} else {
2103			/* Insert before */
2104			BUG_ON(newext->ee_block == nearex->ee_block);
2105			ext_debug("insert %u:%llu:[%d]%d after: "
2106					"nearest %p\n",
2107					le32_to_cpu(newext->ee_block),
2108					ext4_ext_pblock(newext),
2109					ext4_ext_is_unwritten(newext),
2110					ext4_ext_get_actual_len(newext),
2111					nearex);
2112		}
2113		len = EXT_LAST_EXTENT(eh) - nearex + 1;
2114		if (len > 0) {
2115			ext_debug("insert %u:%llu:[%d]%d: "
2116					"move %d extents from 0x%p to 0x%p\n",
2117					le32_to_cpu(newext->ee_block),
2118					ext4_ext_pblock(newext),
2119					ext4_ext_is_unwritten(newext),
2120					ext4_ext_get_actual_len(newext),
2121					len, nearex, nearex + 1);
2122			memmove(nearex + 1, nearex,
2123				len * sizeof(struct ext4_extent));
2124		}
2125	}
2126
2127	le16_add_cpu(&eh->eh_entries, 1);
2128	path[depth].p_ext = nearex;
2129	nearex->ee_block = newext->ee_block;
2130	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2131	nearex->ee_len = newext->ee_len;
2132
2133merge:
2134	/* try to merge extents */
2135	if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2136		ext4_ext_try_to_merge(handle, inode, path, nearex);
2137
2138
2139	/* time to correct all indexes above */
2140	err = ext4_ext_correct_indexes(handle, inode, path);
2141	if (err)
2142		goto cleanup;
2143
2144	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2145
2146cleanup:
2147	ext4_ext_drop_refs(npath);
2148	kfree(npath);
2149	return err;
2150}
2151
2152static int ext4_fill_fiemap_extents(struct inode *inode,
2153				    ext4_lblk_t block, ext4_lblk_t num,
2154				    struct fiemap_extent_info *fieinfo)
2155{
2156	struct ext4_ext_path *path = NULL;
2157	struct ext4_extent *ex;
2158	struct extent_status es;
2159	ext4_lblk_t next, next_del, start = 0, end = 0;
2160	ext4_lblk_t last = block + num;
2161	int exists, depth = 0, err = 0;
2162	unsigned int flags = 0;
2163	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
 
 
2164
2165	while (block < last && block != EXT_MAX_BLOCKS) {
2166		num = last - block;
2167		/* find extent for this block */
2168		down_read(&EXT4_I(inode)->i_data_sem);
2169
2170		path = ext4_find_extent(inode, block, &path, 0);
2171		if (IS_ERR(path)) {
2172			up_read(&EXT4_I(inode)->i_data_sem);
2173			err = PTR_ERR(path);
2174			path = NULL;
2175			break;
2176		}
2177
2178		depth = ext_depth(inode);
2179		if (unlikely(path[depth].p_hdr == NULL)) {
2180			up_read(&EXT4_I(inode)->i_data_sem);
2181			EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2182			err = -EFSCORRUPTED;
2183			break;
2184		}
2185		ex = path[depth].p_ext;
2186		next = ext4_ext_next_allocated_block(path);
2187
2188		flags = 0;
2189		exists = 0;
2190		if (!ex) {
2191			/* there is no extent yet, so try to allocate
2192			 * all requested space */
2193			start = block;
2194			end = block + num;
2195		} else if (le32_to_cpu(ex->ee_block) > block) {
2196			/* need to allocate space before found extent */
2197			start = block;
2198			end = le32_to_cpu(ex->ee_block);
2199			if (block + num < end)
2200				end = block + num;
2201		} else if (block >= le32_to_cpu(ex->ee_block)
2202					+ ext4_ext_get_actual_len(ex)) {
2203			/* need to allocate space after found extent */
2204			start = block;
2205			end = block + num;
2206			if (end >= next)
2207				end = next;
2208		} else if (block >= le32_to_cpu(ex->ee_block)) {
2209			/*
2210			 * some part of requested space is covered
2211			 * by found extent
2212			 */
2213			start = block;
2214			end = le32_to_cpu(ex->ee_block)
2215				+ ext4_ext_get_actual_len(ex);
2216			if (block + num < end)
2217				end = block + num;
2218			exists = 1;
2219		} else {
2220			BUG();
2221		}
2222		BUG_ON(end <= start);
2223
2224		if (!exists) {
2225			es.es_lblk = start;
2226			es.es_len = end - start;
2227			es.es_pblk = 0;
2228		} else {
2229			es.es_lblk = le32_to_cpu(ex->ee_block);
2230			es.es_len = ext4_ext_get_actual_len(ex);
2231			es.es_pblk = ext4_ext_pblock(ex);
2232			if (ext4_ext_is_unwritten(ex))
2233				flags |= FIEMAP_EXTENT_UNWRITTEN;
2234		}
2235
2236		/*
2237		 * Find delayed extent and update es accordingly. We call
2238		 * it even in !exists case to find out whether es is the
2239		 * last existing extent or not.
2240		 */
2241		next_del = ext4_find_delayed_extent(inode, &es);
2242		if (!exists && next_del) {
2243			exists = 1;
2244			flags |= (FIEMAP_EXTENT_DELALLOC |
2245				  FIEMAP_EXTENT_UNKNOWN);
2246		}
2247		up_read(&EXT4_I(inode)->i_data_sem);
2248
2249		if (unlikely(es.es_len == 0)) {
2250			EXT4_ERROR_INODE(inode, "es.es_len == 0");
2251			err = -EFSCORRUPTED;
2252			break;
2253		}
2254
2255		/*
2256		 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2257		 * we need to check next == EXT_MAX_BLOCKS because it is
2258		 * possible that an extent is with unwritten and delayed
2259		 * status due to when an extent is delayed allocated and
2260		 * is allocated by fallocate status tree will track both of
2261		 * them in a extent.
2262		 *
2263		 * So we could return a unwritten and delayed extent, and
2264		 * its block is equal to 'next'.
2265		 */
2266		if (next == next_del && next == EXT_MAX_BLOCKS) {
2267			flags |= FIEMAP_EXTENT_LAST;
2268			if (unlikely(next_del != EXT_MAX_BLOCKS ||
2269				     next != EXT_MAX_BLOCKS)) {
2270				EXT4_ERROR_INODE(inode,
2271						 "next extent == %u, next "
2272						 "delalloc extent = %u",
2273						 next, next_del);
2274				err = -EFSCORRUPTED;
2275				break;
2276			}
2277		}
2278
2279		if (exists) {
2280			err = fiemap_fill_next_extent(fieinfo,
2281				(__u64)es.es_lblk << blksize_bits,
2282				(__u64)es.es_pblk << blksize_bits,
2283				(__u64)es.es_len << blksize_bits,
2284				flags);
2285			if (err < 0)
2286				break;
2287			if (err == 1) {
2288				err = 0;
2289				break;
2290			}
2291		}
2292
2293		block = es.es_lblk + es.es_len;
2294	}
2295
2296	ext4_ext_drop_refs(path);
2297	kfree(path);
2298	return err;
2299}
2300
 
2301/*
2302 * ext4_ext_determine_hole - determine hole around given block
2303 * @inode:	inode we lookup in
2304 * @path:	path in extent tree to @lblk
2305 * @lblk:	pointer to logical block around which we want to determine hole
2306 *
2307 * Determine hole length (and start if easily possible) around given logical
2308 * block. We don't try too hard to find the beginning of the hole but @path
2309 * actually points to extent before @lblk, we provide it.
2310 *
2311 * The function returns the length of a hole starting at @lblk. We update @lblk
2312 * to the beginning of the hole if we managed to find it.
2313 */
2314static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2315					   struct ext4_ext_path *path,
2316					   ext4_lblk_t *lblk)
2317{
2318	int depth = ext_depth(inode);
2319	struct ext4_extent *ex;
2320	ext4_lblk_t len;
2321
2322	ex = path[depth].p_ext;
2323	if (ex == NULL) {
2324		/* there is no extent yet, so gap is [0;-] */
2325		*lblk = 0;
2326		len = EXT_MAX_BLOCKS;
2327	} else if (*lblk < le32_to_cpu(ex->ee_block)) {
2328		len = le32_to_cpu(ex->ee_block) - *lblk;
2329	} else if (*lblk >= le32_to_cpu(ex->ee_block)
2330			+ ext4_ext_get_actual_len(ex)) {
2331		ext4_lblk_t next;
2332
2333		*lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2334		next = ext4_ext_next_allocated_block(path);
2335		BUG_ON(next == *lblk);
2336		len = next - *lblk;
2337	} else {
2338		BUG();
2339	}
2340	return len;
2341}
2342
2343/*
2344 * ext4_ext_put_gap_in_cache:
2345 * calculate boundaries of the gap that the requested block fits into
2346 * and cache this gap
2347 */
2348static void
2349ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2350			  ext4_lblk_t hole_len)
2351{
2352	struct extent_status es;
2353
2354	ext4_es_find_delayed_extent_range(inode, hole_start,
2355					  hole_start + hole_len - 1, &es);
2356	if (es.es_len) {
2357		/* There's delayed extent containing lblock? */
2358		if (es.es_lblk <= hole_start)
2359			return;
2360		hole_len = min(es.es_lblk - hole_start, hole_len);
2361	}
2362	ext_debug(" -> %u:%u\n", hole_start, hole_len);
2363	ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2364			      EXTENT_STATUS_HOLE);
2365}
2366
2367/*
2368 * ext4_ext_rm_idx:
2369 * removes index from the index block.
2370 */
2371static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2372			struct ext4_ext_path *path, int depth)
2373{
2374	int err;
2375	ext4_fsblk_t leaf;
2376
2377	/* free index block */
2378	depth--;
2379	path = path + depth;
2380	leaf = ext4_idx_pblock(path->p_idx);
2381	if (unlikely(path->p_hdr->eh_entries == 0)) {
2382		EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2383		return -EFSCORRUPTED;
2384	}
2385	err = ext4_ext_get_access(handle, inode, path);
2386	if (err)
2387		return err;
2388
2389	if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2390		int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2391		len *= sizeof(struct ext4_extent_idx);
2392		memmove(path->p_idx, path->p_idx + 1, len);
2393	}
2394
2395	le16_add_cpu(&path->p_hdr->eh_entries, -1);
2396	err = ext4_ext_dirty(handle, inode, path);
2397	if (err)
2398		return err;
2399	ext_debug("index is empty, remove it, free block %llu\n", leaf);
2400	trace_ext4_ext_rm_idx(inode, leaf);
2401
2402	ext4_free_blocks(handle, inode, NULL, leaf, 1,
2403			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2404
2405	while (--depth >= 0) {
2406		if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2407			break;
2408		path--;
2409		err = ext4_ext_get_access(handle, inode, path);
2410		if (err)
2411			break;
2412		path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2413		err = ext4_ext_dirty(handle, inode, path);
2414		if (err)
2415			break;
2416	}
2417	return err;
2418}
2419
2420/*
2421 * ext4_ext_calc_credits_for_single_extent:
2422 * This routine returns max. credits that needed to insert an extent
2423 * to the extent tree.
2424 * When pass the actual path, the caller should calculate credits
2425 * under i_data_sem.
2426 */
2427int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2428						struct ext4_ext_path *path)
2429{
2430	if (path) {
2431		int depth = ext_depth(inode);
2432		int ret = 0;
2433
2434		/* probably there is space in leaf? */
2435		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2436				< le16_to_cpu(path[depth].p_hdr->eh_max)) {
2437
2438			/*
2439			 *  There are some space in the leaf tree, no
2440			 *  need to account for leaf block credit
2441			 *
2442			 *  bitmaps and block group descriptor blocks
2443			 *  and other metadata blocks still need to be
2444			 *  accounted.
2445			 */
2446			/* 1 bitmap, 1 block group descriptor */
2447			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2448			return ret;
2449		}
2450	}
2451
2452	return ext4_chunk_trans_blocks(inode, nrblocks);
2453}
2454
2455/*
2456 * How many index/leaf blocks need to change/allocate to add @extents extents?
2457 *
2458 * If we add a single extent, then in the worse case, each tree level
2459 * index/leaf need to be changed in case of the tree split.
2460 *
2461 * If more extents are inserted, they could cause the whole tree split more
2462 * than once, but this is really rare.
2463 */
2464int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2465{
2466	int index;
2467	int depth;
2468
2469	/* If we are converting the inline data, only one is needed here. */
2470	if (ext4_has_inline_data(inode))
2471		return 1;
2472
2473	depth = ext_depth(inode);
2474
2475	if (extents <= 1)
2476		index = depth * 2;
2477	else
2478		index = depth * 3;
2479
2480	return index;
2481}
2482
2483static inline int get_default_free_blocks_flags(struct inode *inode)
2484{
2485	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
 
2486		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2487	else if (ext4_should_journal_data(inode))
2488		return EXT4_FREE_BLOCKS_FORGET;
2489	return 0;
2490}
2491
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2492static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2493			      struct ext4_extent *ex,
2494			      long long *partial_cluster,
2495			      ext4_lblk_t from, ext4_lblk_t to)
2496{
2497	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2498	unsigned short ee_len = ext4_ext_get_actual_len(ex);
2499	ext4_fsblk_t pblk;
2500	int flags = get_default_free_blocks_flags(inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2501
2502	/*
2503	 * For bigalloc file systems, we never free a partial cluster
2504	 * at the beginning of the extent.  Instead, we make a note
2505	 * that we tried freeing the cluster, and check to see if we
2506	 * need to free it on a subsequent call to ext4_remove_blocks,
2507	 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2508	 */
2509	flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2510
2511	trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2512	/*
2513	 * If we have a partial cluster, and it's different from the
2514	 * cluster of the last block, we need to explicitly free the
2515	 * partial cluster here.
2516	 */
2517	pblk = ext4_ext_pblock(ex) + ee_len - 1;
2518	if (*partial_cluster > 0 &&
2519	    *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
 
 
 
 
 
 
2520		ext4_free_blocks(handle, inode, NULL,
2521				 EXT4_C2B(sbi, *partial_cluster),
2522				 sbi->s_cluster_ratio, flags);
2523		*partial_cluster = 0;
 
 
 
2524	}
2525
2526#ifdef EXTENTS_STATS
2527	{
2528		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2529		spin_lock(&sbi->s_ext_stats_lock);
2530		sbi->s_ext_blocks += ee_len;
2531		sbi->s_ext_extents++;
2532		if (ee_len < sbi->s_ext_min)
2533			sbi->s_ext_min = ee_len;
2534		if (ee_len > sbi->s_ext_max)
2535			sbi->s_ext_max = ee_len;
2536		if (ext_depth(inode) > sbi->s_depth_max)
2537			sbi->s_depth_max = ext_depth(inode);
2538		spin_unlock(&sbi->s_ext_stats_lock);
2539	}
2540#endif
2541	if (from >= le32_to_cpu(ex->ee_block)
2542	    && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2543		/* tail removal */
2544		ext4_lblk_t num;
2545		long long first_cluster;
2546
2547		num = le32_to_cpu(ex->ee_block) + ee_len - from;
2548		pblk = ext4_ext_pblock(ex) + ee_len - num;
2549		/*
2550		 * Usually we want to free partial cluster at the end of the
2551		 * extent, except for the situation when the cluster is still
2552		 * used by any other extent (partial_cluster is negative).
2553		 */
2554		if (*partial_cluster < 0 &&
2555		    *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2556			flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2557
2558		ext_debug("free last %u blocks starting %llu partial %lld\n",
2559			  num, pblk, *partial_cluster);
2560		ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2561		/*
2562		 * If the block range to be freed didn't start at the
2563		 * beginning of a cluster, and we removed the entire
2564		 * extent and the cluster is not used by any other extent,
2565		 * save the partial cluster here, since we might need to
2566		 * delete if we determine that the truncate or punch hole
2567		 * operation has removed all of the blocks in the cluster.
2568		 * If that cluster is used by another extent, preserve its
2569		 * negative value so it isn't freed later on.
2570		 *
2571		 * If the whole extent wasn't freed, we've reached the
2572		 * start of the truncated/punched region and have finished
2573		 * removing blocks.  If there's a partial cluster here it's
2574		 * shared with the remainder of the extent and is no longer
2575		 * a candidate for removal.
2576		 */
2577		if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2578			first_cluster = (long long) EXT4_B2C(sbi, pblk);
2579			if (first_cluster != -*partial_cluster)
2580				*partial_cluster = first_cluster;
2581		} else {
2582			*partial_cluster = 0;
2583		}
2584	} else
2585		ext4_error(sbi->s_sb, "strange request: removal(2) "
2586			   "%u-%u from %u:%u\n",
2587			   from, to, le32_to_cpu(ex->ee_block), ee_len);
2588	return 0;
2589}
2590
2591
2592/*
2593 * ext4_ext_rm_leaf() Removes the extents associated with the
2594 * blocks appearing between "start" and "end".  Both "start"
2595 * and "end" must appear in the same extent or EIO is returned.
2596 *
2597 * @handle: The journal handle
2598 * @inode:  The files inode
2599 * @path:   The path to the leaf
2600 * @partial_cluster: The cluster which we'll have to free if all extents
2601 *                   has been released from it.  However, if this value is
2602 *                   negative, it's a cluster just to the right of the
2603 *                   punched region and it must not be freed.
2604 * @start:  The first block to remove
2605 * @end:   The last block to remove
2606 */
2607static int
2608ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2609		 struct ext4_ext_path *path,
2610		 long long *partial_cluster,
2611		 ext4_lblk_t start, ext4_lblk_t end)
2612{
2613	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2614	int err = 0, correct_index = 0;
2615	int depth = ext_depth(inode), credits;
2616	struct ext4_extent_header *eh;
2617	ext4_lblk_t a, b;
2618	unsigned num;
2619	ext4_lblk_t ex_ee_block;
2620	unsigned short ex_ee_len;
2621	unsigned unwritten = 0;
2622	struct ext4_extent *ex;
2623	ext4_fsblk_t pblk;
2624
2625	/* the header must be checked already in ext4_ext_remove_space() */
2626	ext_debug("truncate since %u in leaf to %u\n", start, end);
2627	if (!path[depth].p_hdr)
2628		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2629	eh = path[depth].p_hdr;
2630	if (unlikely(path[depth].p_hdr == NULL)) {
2631		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2632		return -EFSCORRUPTED;
2633	}
2634	/* find where to start removing */
2635	ex = path[depth].p_ext;
2636	if (!ex)
2637		ex = EXT_LAST_EXTENT(eh);
2638
2639	ex_ee_block = le32_to_cpu(ex->ee_block);
2640	ex_ee_len = ext4_ext_get_actual_len(ex);
2641
2642	trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2643
2644	while (ex >= EXT_FIRST_EXTENT(eh) &&
2645			ex_ee_block + ex_ee_len > start) {
2646
2647		if (ext4_ext_is_unwritten(ex))
2648			unwritten = 1;
2649		else
2650			unwritten = 0;
2651
2652		ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2653			  unwritten, ex_ee_len);
2654		path[depth].p_ext = ex;
2655
2656		a = ex_ee_block > start ? ex_ee_block : start;
2657		b = ex_ee_block+ex_ee_len - 1 < end ?
2658			ex_ee_block+ex_ee_len - 1 : end;
2659
2660		ext_debug("  border %u:%u\n", a, b);
2661
2662		/* If this extent is beyond the end of the hole, skip it */
2663		if (end < ex_ee_block) {
2664			/*
2665			 * We're going to skip this extent and move to another,
2666			 * so note that its first cluster is in use to avoid
2667			 * freeing it when removing blocks.  Eventually, the
2668			 * right edge of the truncated/punched region will
2669			 * be just to the left.
2670			 */
2671			if (sbi->s_cluster_ratio > 1) {
2672				pblk = ext4_ext_pblock(ex);
2673				*partial_cluster =
2674					-(long long) EXT4_B2C(sbi, pblk);
2675			}
2676			ex--;
2677			ex_ee_block = le32_to_cpu(ex->ee_block);
2678			ex_ee_len = ext4_ext_get_actual_len(ex);
2679			continue;
2680		} else if (b != ex_ee_block + ex_ee_len - 1) {
2681			EXT4_ERROR_INODE(inode,
2682					 "can not handle truncate %u:%u "
2683					 "on extent %u:%u",
2684					 start, end, ex_ee_block,
2685					 ex_ee_block + ex_ee_len - 1);
2686			err = -EFSCORRUPTED;
2687			goto out;
2688		} else if (a != ex_ee_block) {
2689			/* remove tail of the extent */
2690			num = a - ex_ee_block;
2691		} else {
2692			/* remove whole extent: excellent! */
2693			num = 0;
2694		}
2695		/*
2696		 * 3 for leaf, sb, and inode plus 2 (bmap and group
2697		 * descriptor) for each block group; assume two block
2698		 * groups plus ex_ee_len/blocks_per_block_group for
2699		 * the worst case
2700		 */
2701		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2702		if (ex == EXT_FIRST_EXTENT(eh)) {
2703			correct_index = 1;
2704			credits += (ext_depth(inode)) + 1;
2705		}
2706		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2707
2708		err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2709		if (err)
 
 
 
 
 
 
 
 
 
 
 
 
2710			goto out;
 
2711
2712		err = ext4_ext_get_access(handle, inode, path + depth);
2713		if (err)
2714			goto out;
2715
2716		err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2717					 a, b);
2718		if (err)
2719			goto out;
2720
2721		if (num == 0)
2722			/* this extent is removed; mark slot entirely unused */
2723			ext4_ext_store_pblock(ex, 0);
2724
2725		ex->ee_len = cpu_to_le16(num);
2726		/*
2727		 * Do not mark unwritten if all the blocks in the
2728		 * extent have been removed.
2729		 */
2730		if (unwritten && num)
2731			ext4_ext_mark_unwritten(ex);
2732		/*
2733		 * If the extent was completely released,
2734		 * we need to remove it from the leaf
2735		 */
2736		if (num == 0) {
2737			if (end != EXT_MAX_BLOCKS - 1) {
2738				/*
2739				 * For hole punching, we need to scoot all the
2740				 * extents up when an extent is removed so that
2741				 * we dont have blank extents in the middle
2742				 */
2743				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2744					sizeof(struct ext4_extent));
2745
2746				/* Now get rid of the one at the end */
2747				memset(EXT_LAST_EXTENT(eh), 0,
2748					sizeof(struct ext4_extent));
2749			}
2750			le16_add_cpu(&eh->eh_entries, -1);
2751		}
2752
2753		err = ext4_ext_dirty(handle, inode, path + depth);
2754		if (err)
2755			goto out;
2756
2757		ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2758				ext4_ext_pblock(ex));
2759		ex--;
2760		ex_ee_block = le32_to_cpu(ex->ee_block);
2761		ex_ee_len = ext4_ext_get_actual_len(ex);
2762	}
2763
2764	if (correct_index && eh->eh_entries)
2765		err = ext4_ext_correct_indexes(handle, inode, path);
2766
2767	/*
2768	 * If there's a partial cluster and at least one extent remains in
2769	 * the leaf, free the partial cluster if it isn't shared with the
2770	 * current extent.  If it is shared with the current extent
2771	 * we zero partial_cluster because we've reached the start of the
2772	 * truncated/punched region and we're done removing blocks.
2773	 */
2774	if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2775		pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2776		if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
 
 
 
 
2777			ext4_free_blocks(handle, inode, NULL,
2778					 EXT4_C2B(sbi, *partial_cluster),
2779					 sbi->s_cluster_ratio,
2780					 get_default_free_blocks_flags(inode));
 
2781		}
2782		*partial_cluster = 0;
2783	}
2784
2785	/* if this leaf is free, then we should
2786	 * remove it from index block above */
2787	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2788		err = ext4_ext_rm_idx(handle, inode, path, depth);
2789
2790out:
2791	return err;
2792}
2793
2794/*
2795 * ext4_ext_more_to_rm:
2796 * returns 1 if current index has to be freed (even partial)
2797 */
2798static int
2799ext4_ext_more_to_rm(struct ext4_ext_path *path)
2800{
2801	BUG_ON(path->p_idx == NULL);
2802
2803	if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2804		return 0;
2805
2806	/*
2807	 * if truncate on deeper level happened, it wasn't partial,
2808	 * so we have to consider current index for truncation
2809	 */
2810	if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2811		return 0;
2812	return 1;
2813}
2814
2815int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2816			  ext4_lblk_t end)
2817{
2818	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2819	int depth = ext_depth(inode);
2820	struct ext4_ext_path *path = NULL;
2821	long long partial_cluster = 0;
2822	handle_t *handle;
2823	int i = 0, err = 0;
2824
2825	ext_debug("truncate since %u to %u\n", start, end);
 
 
 
 
2826
2827	/* probably first extent we're gonna free will be last in block */
2828	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
 
 
2829	if (IS_ERR(handle))
2830		return PTR_ERR(handle);
2831
2832again:
2833	trace_ext4_ext_remove_space(inode, start, end, depth);
2834
2835	/*
2836	 * Check if we are removing extents inside the extent tree. If that
2837	 * is the case, we are going to punch a hole inside the extent tree
2838	 * so we have to check whether we need to split the extent covering
2839	 * the last block to remove so we can easily remove the part of it
2840	 * in ext4_ext_rm_leaf().
2841	 */
2842	if (end < EXT_MAX_BLOCKS - 1) {
2843		struct ext4_extent *ex;
2844		ext4_lblk_t ee_block, ex_end, lblk;
2845		ext4_fsblk_t pblk;
2846
2847		/* find extent for or closest extent to this block */
2848		path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
 
2849		if (IS_ERR(path)) {
2850			ext4_journal_stop(handle);
2851			return PTR_ERR(path);
2852		}
2853		depth = ext_depth(inode);
2854		/* Leaf not may not exist only if inode has no blocks at all */
2855		ex = path[depth].p_ext;
2856		if (!ex) {
2857			if (depth) {
2858				EXT4_ERROR_INODE(inode,
2859						 "path[%d].p_hdr == NULL",
2860						 depth);
2861				err = -EFSCORRUPTED;
2862			}
2863			goto out;
2864		}
2865
2866		ee_block = le32_to_cpu(ex->ee_block);
2867		ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2868
2869		/*
2870		 * See if the last block is inside the extent, if so split
2871		 * the extent at 'end' block so we can easily remove the
2872		 * tail of the first part of the split extent in
2873		 * ext4_ext_rm_leaf().
2874		 */
2875		if (end >= ee_block && end < ex_end) {
2876
2877			/*
2878			 * If we're going to split the extent, note that
2879			 * the cluster containing the block after 'end' is
2880			 * in use to avoid freeing it when removing blocks.
2881			 */
2882			if (sbi->s_cluster_ratio > 1) {
2883				pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2884				partial_cluster =
2885					-(long long) EXT4_B2C(sbi, pblk);
2886			}
2887
2888			/*
2889			 * Split the extent in two so that 'end' is the last
2890			 * block in the first new extent. Also we should not
2891			 * fail removing space due to ENOSPC so try to use
2892			 * reserved block if that happens.
2893			 */
2894			err = ext4_force_split_extent_at(handle, inode, &path,
2895							 end + 1, 1);
2896			if (err < 0)
2897				goto out;
2898
2899		} else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
 
2900			/*
2901			 * If there's an extent to the right its first cluster
2902			 * contains the immediate right boundary of the
2903			 * truncated/punched region.  Set partial_cluster to
2904			 * its negative value so it won't be freed if shared
2905			 * with the current extent.  The end < ee_block case
2906			 * is handled in ext4_ext_rm_leaf().
 
 
2907			 */
2908			lblk = ex_end + 1;
2909			err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2910						    &ex);
2911			if (err)
2912				goto out;
2913			if (pblk)
2914				partial_cluster =
2915					-(long long) EXT4_B2C(sbi, pblk);
 
2916		}
2917	}
2918	/*
2919	 * We start scanning from right side, freeing all the blocks
2920	 * after i_size and walking into the tree depth-wise.
2921	 */
2922	depth = ext_depth(inode);
2923	if (path) {
2924		int k = i = depth;
2925		while (--k > 0)
2926			path[k].p_block =
2927				le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2928	} else {
2929		path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2930			       GFP_NOFS);
2931		if (path == NULL) {
2932			ext4_journal_stop(handle);
2933			return -ENOMEM;
2934		}
2935		path[0].p_maxdepth = path[0].p_depth = depth;
2936		path[0].p_hdr = ext_inode_hdr(inode);
2937		i = 0;
2938
2939		if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2940			err = -EFSCORRUPTED;
2941			goto out;
2942		}
2943	}
2944	err = 0;
2945
2946	while (i >= 0 && err == 0) {
2947		if (i == depth) {
2948			/* this is leaf block */
2949			err = ext4_ext_rm_leaf(handle, inode, path,
2950					       &partial_cluster, start,
2951					       end);
2952			/* root level has p_bh == NULL, brelse() eats this */
2953			brelse(path[i].p_bh);
2954			path[i].p_bh = NULL;
2955			i--;
2956			continue;
2957		}
2958
2959		/* this is index block */
2960		if (!path[i].p_hdr) {
2961			ext_debug("initialize header\n");
2962			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2963		}
2964
2965		if (!path[i].p_idx) {
2966			/* this level hasn't been touched yet */
2967			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2968			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2969			ext_debug("init index ptr: hdr 0x%p, num %d\n",
2970				  path[i].p_hdr,
2971				  le16_to_cpu(path[i].p_hdr->eh_entries));
2972		} else {
2973			/* we were already here, see at next index */
2974			path[i].p_idx--;
2975		}
2976
2977		ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2978				i, EXT_FIRST_INDEX(path[i].p_hdr),
2979				path[i].p_idx);
2980		if (ext4_ext_more_to_rm(path + i)) {
2981			struct buffer_head *bh;
2982			/* go to the next level */
2983			ext_debug("move to level %d (block %llu)\n",
2984				  i + 1, ext4_idx_pblock(path[i].p_idx));
2985			memset(path + i + 1, 0, sizeof(*path));
2986			bh = read_extent_tree_block(inode,
2987				ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2988				EXT4_EX_NOCACHE);
2989			if (IS_ERR(bh)) {
2990				/* should we reset i_size? */
2991				err = PTR_ERR(bh);
2992				break;
2993			}
2994			/* Yield here to deal with large extent trees.
2995			 * Should be a no-op if we did IO above. */
2996			cond_resched();
2997			if (WARN_ON(i + 1 > depth)) {
2998				err = -EFSCORRUPTED;
2999				break;
3000			}
3001			path[i + 1].p_bh = bh;
3002
3003			/* save actual number of indexes since this
3004			 * number is changed at the next iteration */
3005			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3006			i++;
3007		} else {
3008			/* we finished processing this index, go up */
3009			if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3010				/* index is empty, remove it;
3011				 * handle must be already prepared by the
3012				 * truncatei_leaf() */
3013				err = ext4_ext_rm_idx(handle, inode, path, i);
3014			}
3015			/* root level has p_bh == NULL, brelse() eats this */
3016			brelse(path[i].p_bh);
3017			path[i].p_bh = NULL;
3018			i--;
3019			ext_debug("return to level %d\n", i);
3020		}
3021	}
3022
3023	trace_ext4_ext_remove_space_done(inode, start, end, depth,
3024			partial_cluster, path->p_hdr->eh_entries);
3025
3026	/*
3027	 * If we still have something in the partial cluster and we have removed
3028	 * even the first extent, then we should free the blocks in the partial
3029	 * cluster as well.  (This code will only run when there are no leaves
3030	 * to the immediate left of the truncated/punched region.)
3031	 */
3032	if (partial_cluster > 0 && err == 0) {
3033		/* don't zero partial_cluster since it's not used afterwards */
 
 
 
3034		ext4_free_blocks(handle, inode, NULL,
3035				 EXT4_C2B(sbi, partial_cluster),
3036				 sbi->s_cluster_ratio,
3037				 get_default_free_blocks_flags(inode));
 
 
3038	}
3039
3040	/* TODO: flexible tree reduction should be here */
3041	if (path->p_hdr->eh_entries == 0) {
3042		/*
3043		 * truncate to zero freed all the tree,
3044		 * so we need to correct eh_depth
3045		 */
3046		err = ext4_ext_get_access(handle, inode, path);
3047		if (err == 0) {
3048			ext_inode_hdr(inode)->eh_depth = 0;
3049			ext_inode_hdr(inode)->eh_max =
3050				cpu_to_le16(ext4_ext_space_root(inode, 0));
3051			err = ext4_ext_dirty(handle, inode, path);
3052		}
3053	}
3054out:
3055	ext4_ext_drop_refs(path);
3056	kfree(path);
3057	path = NULL;
3058	if (err == -EAGAIN)
3059		goto again;
3060	ext4_journal_stop(handle);
3061
3062	return err;
3063}
3064
3065/*
3066 * called at mount time
3067 */
3068void ext4_ext_init(struct super_block *sb)
3069{
3070	/*
3071	 * possible initialization would be here
3072	 */
3073
3074	if (ext4_has_feature_extents(sb)) {
3075#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3076		printk(KERN_INFO "EXT4-fs: file extents enabled"
3077#ifdef AGGRESSIVE_TEST
3078		       ", aggressive tests"
3079#endif
3080#ifdef CHECK_BINSEARCH
3081		       ", check binsearch"
3082#endif
3083#ifdef EXTENTS_STATS
3084		       ", stats"
3085#endif
3086		       "\n");
3087#endif
3088#ifdef EXTENTS_STATS
3089		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3090		EXT4_SB(sb)->s_ext_min = 1 << 30;
3091		EXT4_SB(sb)->s_ext_max = 0;
3092#endif
3093	}
3094}
3095
3096/*
3097 * called at umount time
3098 */
3099void ext4_ext_release(struct super_block *sb)
3100{
3101	if (!ext4_has_feature_extents(sb))
3102		return;
3103
3104#ifdef EXTENTS_STATS
3105	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3106		struct ext4_sb_info *sbi = EXT4_SB(sb);
3107		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3108			sbi->s_ext_blocks, sbi->s_ext_extents,
3109			sbi->s_ext_blocks / sbi->s_ext_extents);
3110		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3111			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3112	}
3113#endif
3114}
3115
3116static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3117{
3118	ext4_lblk_t  ee_block;
3119	ext4_fsblk_t ee_pblock;
3120	unsigned int ee_len;
3121
3122	ee_block  = le32_to_cpu(ex->ee_block);
3123	ee_len    = ext4_ext_get_actual_len(ex);
3124	ee_pblock = ext4_ext_pblock(ex);
3125
3126	if (ee_len == 0)
3127		return 0;
3128
3129	return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3130				     EXTENT_STATUS_WRITTEN);
3131}
3132
3133/* FIXME!! we need to try to merge to left or right after zero-out  */
3134static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3135{
3136	ext4_fsblk_t ee_pblock;
3137	unsigned int ee_len;
3138
3139	ee_len    = ext4_ext_get_actual_len(ex);
3140	ee_pblock = ext4_ext_pblock(ex);
3141	return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3142				  ee_len);
3143}
3144
3145/*
3146 * ext4_split_extent_at() splits an extent at given block.
3147 *
3148 * @handle: the journal handle
3149 * @inode: the file inode
3150 * @path: the path to the extent
3151 * @split: the logical block where the extent is splitted.
3152 * @split_flags: indicates if the extent could be zeroout if split fails, and
3153 *		 the states(init or unwritten) of new extents.
3154 * @flags: flags used to insert new extent to extent tree.
3155 *
3156 *
3157 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3158 * of which are deterimined by split_flag.
3159 *
3160 * There are two cases:
3161 *  a> the extent are splitted into two extent.
3162 *  b> split is not needed, and just mark the extent.
3163 *
3164 * return 0 on success.
3165 */
3166static int ext4_split_extent_at(handle_t *handle,
3167			     struct inode *inode,
3168			     struct ext4_ext_path **ppath,
3169			     ext4_lblk_t split,
3170			     int split_flag,
3171			     int flags)
3172{
3173	struct ext4_ext_path *path = *ppath;
3174	ext4_fsblk_t newblock;
3175	ext4_lblk_t ee_block;
3176	struct ext4_extent *ex, newex, orig_ex, zero_ex;
3177	struct ext4_extent *ex2 = NULL;
3178	unsigned int ee_len, depth;
3179	int err = 0;
3180
3181	BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3182	       (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3183
3184	ext_debug("ext4_split_extents_at: inode %lu, logical"
3185		"block %llu\n", inode->i_ino, (unsigned long long)split);
3186
3187	ext4_ext_show_leaf(inode, path);
3188
3189	depth = ext_depth(inode);
3190	ex = path[depth].p_ext;
3191	ee_block = le32_to_cpu(ex->ee_block);
3192	ee_len = ext4_ext_get_actual_len(ex);
3193	newblock = split - ee_block + ext4_ext_pblock(ex);
3194
3195	BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3196	BUG_ON(!ext4_ext_is_unwritten(ex) &&
3197	       split_flag & (EXT4_EXT_MAY_ZEROOUT |
3198			     EXT4_EXT_MARK_UNWRIT1 |
3199			     EXT4_EXT_MARK_UNWRIT2));
3200
3201	err = ext4_ext_get_access(handle, inode, path + depth);
3202	if (err)
3203		goto out;
3204
3205	if (split == ee_block) {
3206		/*
3207		 * case b: block @split is the block that the extent begins with
3208		 * then we just change the state of the extent, and splitting
3209		 * is not needed.
3210		 */
3211		if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3212			ext4_ext_mark_unwritten(ex);
3213		else
3214			ext4_ext_mark_initialized(ex);
3215
3216		if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3217			ext4_ext_try_to_merge(handle, inode, path, ex);
3218
3219		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3220		goto out;
3221	}
3222
3223	/* case a */
3224	memcpy(&orig_ex, ex, sizeof(orig_ex));
3225	ex->ee_len = cpu_to_le16(split - ee_block);
3226	if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3227		ext4_ext_mark_unwritten(ex);
3228
3229	/*
3230	 * path may lead to new leaf, not to original leaf any more
3231	 * after ext4_ext_insert_extent() returns,
3232	 */
3233	err = ext4_ext_dirty(handle, inode, path + depth);
3234	if (err)
3235		goto fix_extent_len;
3236
3237	ex2 = &newex;
3238	ex2->ee_block = cpu_to_le32(split);
3239	ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3240	ext4_ext_store_pblock(ex2, newblock);
3241	if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3242		ext4_ext_mark_unwritten(ex2);
3243
3244	err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3245	if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
 
 
 
3246		if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3247			if (split_flag & EXT4_EXT_DATA_VALID1) {
3248				err = ext4_ext_zeroout(inode, ex2);
3249				zero_ex.ee_block = ex2->ee_block;
3250				zero_ex.ee_len = cpu_to_le16(
3251						ext4_ext_get_actual_len(ex2));
3252				ext4_ext_store_pblock(&zero_ex,
3253						      ext4_ext_pblock(ex2));
3254			} else {
3255				err = ext4_ext_zeroout(inode, ex);
3256				zero_ex.ee_block = ex->ee_block;
3257				zero_ex.ee_len = cpu_to_le16(
3258						ext4_ext_get_actual_len(ex));
3259				ext4_ext_store_pblock(&zero_ex,
3260						      ext4_ext_pblock(ex));
3261			}
3262		} else {
3263			err = ext4_ext_zeroout(inode, &orig_ex);
3264			zero_ex.ee_block = orig_ex.ee_block;
3265			zero_ex.ee_len = cpu_to_le16(
3266						ext4_ext_get_actual_len(&orig_ex));
3267			ext4_ext_store_pblock(&zero_ex,
3268					      ext4_ext_pblock(&orig_ex));
3269		}
3270
3271		if (err)
3272			goto fix_extent_len;
3273		/* update the extent length and mark as initialized */
3274		ex->ee_len = cpu_to_le16(ee_len);
3275		ext4_ext_try_to_merge(handle, inode, path, ex);
3276		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3277		if (err)
3278			goto fix_extent_len;
3279
3280		/* update extent status tree */
3281		err = ext4_zeroout_es(inode, &zero_ex);
3282
3283		goto out;
3284	} else if (err)
3285		goto fix_extent_len;
3286
3287out:
3288	ext4_ext_show_leaf(inode, path);
3289	return err;
3290
3291fix_extent_len:
3292	ex->ee_len = orig_ex.ee_len;
 
 
 
 
3293	ext4_ext_dirty(handle, inode, path + path->p_depth);
3294	return err;
 
 
 
3295}
3296
3297/*
3298 * ext4_split_extents() splits an extent and mark extent which is covered
3299 * by @map as split_flags indicates
3300 *
3301 * It may result in splitting the extent into multiple extents (up to three)
3302 * There are three possibilities:
3303 *   a> There is no split required
3304 *   b> Splits in two extents: Split is happening at either end of the extent
3305 *   c> Splits in three extents: Somone is splitting in middle of the extent
3306 *
3307 */
3308static int ext4_split_extent(handle_t *handle,
3309			      struct inode *inode,
3310			      struct ext4_ext_path **ppath,
3311			      struct ext4_map_blocks *map,
3312			      int split_flag,
3313			      int flags)
3314{
3315	struct ext4_ext_path *path = *ppath;
3316	ext4_lblk_t ee_block;
3317	struct ext4_extent *ex;
3318	unsigned int ee_len, depth;
3319	int err = 0;
3320	int unwritten;
3321	int split_flag1, flags1;
3322	int allocated = map->m_len;
3323
3324	depth = ext_depth(inode);
3325	ex = path[depth].p_ext;
3326	ee_block = le32_to_cpu(ex->ee_block);
3327	ee_len = ext4_ext_get_actual_len(ex);
3328	unwritten = ext4_ext_is_unwritten(ex);
3329
3330	if (map->m_lblk + map->m_len < ee_block + ee_len) {
3331		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3332		flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3333		if (unwritten)
3334			split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3335				       EXT4_EXT_MARK_UNWRIT2;
3336		if (split_flag & EXT4_EXT_DATA_VALID2)
3337			split_flag1 |= EXT4_EXT_DATA_VALID1;
3338		err = ext4_split_extent_at(handle, inode, ppath,
3339				map->m_lblk + map->m_len, split_flag1, flags1);
3340		if (err)
3341			goto out;
3342	} else {
3343		allocated = ee_len - (map->m_lblk - ee_block);
3344	}
3345	/*
3346	 * Update path is required because previous ext4_split_extent_at() may
3347	 * result in split of original leaf or extent zeroout.
3348	 */
3349	path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3350	if (IS_ERR(path))
3351		return PTR_ERR(path);
3352	depth = ext_depth(inode);
3353	ex = path[depth].p_ext;
3354	if (!ex) {
3355		EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3356				 (unsigned long) map->m_lblk);
3357		return -EFSCORRUPTED;
3358	}
3359	unwritten = ext4_ext_is_unwritten(ex);
3360	split_flag1 = 0;
3361
3362	if (map->m_lblk >= ee_block) {
3363		split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3364		if (unwritten) {
3365			split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3366			split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3367						     EXT4_EXT_MARK_UNWRIT2);
3368		}
3369		err = ext4_split_extent_at(handle, inode, ppath,
3370				map->m_lblk, split_flag1, flags);
3371		if (err)
3372			goto out;
3373	}
3374
3375	ext4_ext_show_leaf(inode, path);
3376out:
3377	return err ? err : allocated;
3378}
3379
3380/*
3381 * This function is called by ext4_ext_map_blocks() if someone tries to write
3382 * to an unwritten extent. It may result in splitting the unwritten
3383 * extent into multiple extents (up to three - one initialized and two
3384 * unwritten).
3385 * There are three possibilities:
3386 *   a> There is no split required: Entire extent should be initialized
3387 *   b> Splits in two extents: Write is happening at either end of the extent
3388 *   c> Splits in three extents: Somone is writing in middle of the extent
3389 *
3390 * Pre-conditions:
3391 *  - The extent pointed to by 'path' is unwritten.
3392 *  - The extent pointed to by 'path' contains a superset
3393 *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3394 *
3395 * Post-conditions on success:
3396 *  - the returned value is the number of blocks beyond map->l_lblk
3397 *    that are allocated and initialized.
3398 *    It is guaranteed to be >= map->m_len.
3399 */
3400static int ext4_ext_convert_to_initialized(handle_t *handle,
3401					   struct inode *inode,
3402					   struct ext4_map_blocks *map,
3403					   struct ext4_ext_path **ppath,
3404					   int flags)
3405{
3406	struct ext4_ext_path *path = *ppath;
3407	struct ext4_sb_info *sbi;
3408	struct ext4_extent_header *eh;
3409	struct ext4_map_blocks split_map;
3410	struct ext4_extent zero_ex;
3411	struct ext4_extent *ex, *abut_ex;
3412	ext4_lblk_t ee_block, eof_block;
3413	unsigned int ee_len, depth, map_len = map->m_len;
3414	int allocated = 0, max_zeroout = 0;
3415	int err = 0;
3416	int split_flag = 0;
3417
3418	ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3419		"block %llu, max_blocks %u\n", inode->i_ino,
3420		(unsigned long long)map->m_lblk, map_len);
3421
3422	sbi = EXT4_SB(inode->i_sb);
3423	eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3424		inode->i_sb->s_blocksize_bits;
3425	if (eof_block < map->m_lblk + map_len)
3426		eof_block = map->m_lblk + map_len;
3427
3428	depth = ext_depth(inode);
3429	eh = path[depth].p_hdr;
3430	ex = path[depth].p_ext;
3431	ee_block = le32_to_cpu(ex->ee_block);
3432	ee_len = ext4_ext_get_actual_len(ex);
3433	zero_ex.ee_len = 0;
 
3434
3435	trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3436
3437	/* Pre-conditions */
3438	BUG_ON(!ext4_ext_is_unwritten(ex));
3439	BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3440
3441	/*
3442	 * Attempt to transfer newly initialized blocks from the currently
3443	 * unwritten extent to its neighbor. This is much cheaper
3444	 * than an insertion followed by a merge as those involve costly
3445	 * memmove() calls. Transferring to the left is the common case in
3446	 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3447	 * followed by append writes.
3448	 *
3449	 * Limitations of the current logic:
3450	 *  - L1: we do not deal with writes covering the whole extent.
3451	 *    This would require removing the extent if the transfer
3452	 *    is possible.
3453	 *  - L2: we only attempt to merge with an extent stored in the
3454	 *    same extent tree node.
3455	 */
3456	if ((map->m_lblk == ee_block) &&
3457		/* See if we can merge left */
3458		(map_len < ee_len) &&		/*L1*/
3459		(ex > EXT_FIRST_EXTENT(eh))) {	/*L2*/
3460		ext4_lblk_t prev_lblk;
3461		ext4_fsblk_t prev_pblk, ee_pblk;
3462		unsigned int prev_len;
3463
3464		abut_ex = ex - 1;
3465		prev_lblk = le32_to_cpu(abut_ex->ee_block);
3466		prev_len = ext4_ext_get_actual_len(abut_ex);
3467		prev_pblk = ext4_ext_pblock(abut_ex);
3468		ee_pblk = ext4_ext_pblock(ex);
3469
3470		/*
3471		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3472		 * upon those conditions:
3473		 * - C1: abut_ex is initialized,
3474		 * - C2: abut_ex is logically abutting ex,
3475		 * - C3: abut_ex is physically abutting ex,
3476		 * - C4: abut_ex can receive the additional blocks without
3477		 *   overflowing the (initialized) length limit.
3478		 */
3479		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
3480			((prev_lblk + prev_len) == ee_block) &&		/*C2*/
3481			((prev_pblk + prev_len) == ee_pblk) &&		/*C3*/
3482			(prev_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
3483			err = ext4_ext_get_access(handle, inode, path + depth);
3484			if (err)
3485				goto out;
3486
3487			trace_ext4_ext_convert_to_initialized_fastpath(inode,
3488				map, ex, abut_ex);
3489
3490			/* Shift the start of ex by 'map_len' blocks */
3491			ex->ee_block = cpu_to_le32(ee_block + map_len);
3492			ext4_ext_store_pblock(ex, ee_pblk + map_len);
3493			ex->ee_len = cpu_to_le16(ee_len - map_len);
3494			ext4_ext_mark_unwritten(ex); /* Restore the flag */
3495
3496			/* Extend abut_ex by 'map_len' blocks */
3497			abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3498
3499			/* Result: number of initialized blocks past m_lblk */
3500			allocated = map_len;
3501		}
3502	} else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3503		   (map_len < ee_len) &&	/*L1*/
3504		   ex < EXT_LAST_EXTENT(eh)) {	/*L2*/
3505		/* See if we can merge right */
3506		ext4_lblk_t next_lblk;
3507		ext4_fsblk_t next_pblk, ee_pblk;
3508		unsigned int next_len;
3509
3510		abut_ex = ex + 1;
3511		next_lblk = le32_to_cpu(abut_ex->ee_block);
3512		next_len = ext4_ext_get_actual_len(abut_ex);
3513		next_pblk = ext4_ext_pblock(abut_ex);
3514		ee_pblk = ext4_ext_pblock(ex);
3515
3516		/*
3517		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3518		 * upon those conditions:
3519		 * - C1: abut_ex is initialized,
3520		 * - C2: abut_ex is logically abutting ex,
3521		 * - C3: abut_ex is physically abutting ex,
3522		 * - C4: abut_ex can receive the additional blocks without
3523		 *   overflowing the (initialized) length limit.
3524		 */
3525		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
3526		    ((map->m_lblk + map_len) == next_lblk) &&		/*C2*/
3527		    ((ee_pblk + ee_len) == next_pblk) &&		/*C3*/
3528		    (next_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
3529			err = ext4_ext_get_access(handle, inode, path + depth);
3530			if (err)
3531				goto out;
3532
3533			trace_ext4_ext_convert_to_initialized_fastpath(inode,
3534				map, ex, abut_ex);
3535
3536			/* Shift the start of abut_ex by 'map_len' blocks */
3537			abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3538			ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3539			ex->ee_len = cpu_to_le16(ee_len - map_len);
3540			ext4_ext_mark_unwritten(ex); /* Restore the flag */
3541
3542			/* Extend abut_ex by 'map_len' blocks */
3543			abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3544
3545			/* Result: number of initialized blocks past m_lblk */
3546			allocated = map_len;
3547		}
3548	}
3549	if (allocated) {
3550		/* Mark the block containing both extents as dirty */
3551		ext4_ext_dirty(handle, inode, path + depth);
3552
3553		/* Update path to point to the right extent */
3554		path[depth].p_ext = abut_ex;
3555		goto out;
3556	} else
3557		allocated = ee_len - (map->m_lblk - ee_block);
3558
3559	WARN_ON(map->m_lblk < ee_block);
3560	/*
3561	 * It is safe to convert extent to initialized via explicit
3562	 * zeroout only if extent is fully inside i_size or new_size.
3563	 */
3564	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3565
3566	if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3567		max_zeroout = sbi->s_extent_max_zeroout_kb >>
3568			(inode->i_sb->s_blocksize_bits - 10);
3569
3570	if (ext4_encrypted_inode(inode))
3571		max_zeroout = 0;
3572
3573	/* If extent is less than s_max_zeroout_kb, zeroout directly */
3574	if (max_zeroout && (ee_len <= max_zeroout)) {
3575		err = ext4_ext_zeroout(inode, ex);
3576		if (err)
3577			goto out;
3578		zero_ex.ee_block = ex->ee_block;
3579		zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3580		ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3581
3582		err = ext4_ext_get_access(handle, inode, path + depth);
3583		if (err)
3584			goto out;
3585		ext4_ext_mark_initialized(ex);
3586		ext4_ext_try_to_merge(handle, inode, path, ex);
3587		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3588		goto out;
3589	}
3590
3591	/*
3592	 * four cases:
3593	 * 1. split the extent into three extents.
3594	 * 2. split the extent into two extents, zeroout the first half.
3595	 * 3. split the extent into two extents, zeroout the second half.
 
 
3596	 * 4. split the extent into two extents with out zeroout.
 
 
3597	 */
3598	split_map.m_lblk = map->m_lblk;
3599	split_map.m_len = map->m_len;
3600
3601	if (max_zeroout && (allocated > map->m_len)) {
3602		if (allocated <= max_zeroout) {
3603			/* case 3 */
3604			zero_ex.ee_block =
3605					 cpu_to_le32(map->m_lblk);
3606			zero_ex.ee_len = cpu_to_le16(allocated);
3607			ext4_ext_store_pblock(&zero_ex,
3608				ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3609			err = ext4_ext_zeroout(inode, &zero_ex);
 
 
 
3610			if (err)
3611				goto out;
3612			split_map.m_lblk = map->m_lblk;
3613			split_map.m_len = allocated;
3614		} else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3615			/* case 2 */
3616			if (map->m_lblk != ee_block) {
3617				zero_ex.ee_block = ex->ee_block;
3618				zero_ex.ee_len = cpu_to_le16(map->m_lblk -
 
 
3619							ee_block);
3620				ext4_ext_store_pblock(&zero_ex,
3621						      ext4_ext_pblock(ex));
3622				err = ext4_ext_zeroout(inode, &zero_ex);
3623				if (err)
3624					goto out;
3625			}
3626
 
3627			split_map.m_lblk = ee_block;
3628			split_map.m_len = map->m_lblk - ee_block + map->m_len;
3629			allocated = map->m_len;
3630		}
3631	}
3632
 
3633	err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3634				flags);
3635	if (err > 0)
3636		err = 0;
3637out:
3638	/* If we have gotten a failure, don't zero out status tree */
3639	if (!err)
3640		err = ext4_zeroout_es(inode, &zero_ex);
 
 
3641	return err ? err : allocated;
3642}
3643
3644/*
3645 * This function is called by ext4_ext_map_blocks() from
3646 * ext4_get_blocks_dio_write() when DIO to write
3647 * to an unwritten extent.
3648 *
3649 * Writing to an unwritten extent may result in splitting the unwritten
3650 * extent into multiple initialized/unwritten extents (up to three)
3651 * There are three possibilities:
3652 *   a> There is no split required: Entire extent should be unwritten
3653 *   b> Splits in two extents: Write is happening at either end of the extent
3654 *   c> Splits in three extents: Somone is writing in middle of the extent
3655 *
3656 * This works the same way in the case of initialized -> unwritten conversion.
3657 *
3658 * One of more index blocks maybe needed if the extent tree grow after
3659 * the unwritten extent split. To prevent ENOSPC occur at the IO
3660 * complete, we need to split the unwritten extent before DIO submit
3661 * the IO. The unwritten extent called at this time will be split
3662 * into three unwritten extent(at most). After IO complete, the part
3663 * being filled will be convert to initialized by the end_io callback function
3664 * via ext4_convert_unwritten_extents().
3665 *
3666 * Returns the size of unwritten extent to be written on success.
3667 */
3668static int ext4_split_convert_extents(handle_t *handle,
3669					struct inode *inode,
3670					struct ext4_map_blocks *map,
3671					struct ext4_ext_path **ppath,
3672					int flags)
3673{
3674	struct ext4_ext_path *path = *ppath;
3675	ext4_lblk_t eof_block;
3676	ext4_lblk_t ee_block;
3677	struct ext4_extent *ex;
3678	unsigned int ee_len;
3679	int split_flag = 0, depth;
3680
3681	ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3682		  __func__, inode->i_ino,
3683		  (unsigned long long)map->m_lblk, map->m_len);
3684
3685	eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3686		inode->i_sb->s_blocksize_bits;
3687	if (eof_block < map->m_lblk + map->m_len)
3688		eof_block = map->m_lblk + map->m_len;
3689	/*
3690	 * It is safe to convert extent to initialized via explicit
3691	 * zeroout only if extent is fully insde i_size or new_size.
3692	 */
3693	depth = ext_depth(inode);
3694	ex = path[depth].p_ext;
3695	ee_block = le32_to_cpu(ex->ee_block);
3696	ee_len = ext4_ext_get_actual_len(ex);
3697
3698	/* Convert to unwritten */
3699	if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3700		split_flag |= EXT4_EXT_DATA_VALID1;
3701	/* Convert to initialized */
3702	} else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3703		split_flag |= ee_block + ee_len <= eof_block ?
3704			      EXT4_EXT_MAY_ZEROOUT : 0;
3705		split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3706	}
3707	flags |= EXT4_GET_BLOCKS_PRE_IO;
3708	return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3709}
3710
3711static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3712						struct inode *inode,
3713						struct ext4_map_blocks *map,
3714						struct ext4_ext_path **ppath)
3715{
3716	struct ext4_ext_path *path = *ppath;
3717	struct ext4_extent *ex;
3718	ext4_lblk_t ee_block;
3719	unsigned int ee_len;
3720	int depth;
3721	int err = 0;
3722
3723	depth = ext_depth(inode);
3724	ex = path[depth].p_ext;
3725	ee_block = le32_to_cpu(ex->ee_block);
3726	ee_len = ext4_ext_get_actual_len(ex);
3727
3728	ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3729		"block %llu, max_blocks %u\n", inode->i_ino,
3730		  (unsigned long long)ee_block, ee_len);
3731
3732	/* If extent is larger than requested it is a clear sign that we still
3733	 * have some extent state machine issues left. So extent_split is still
3734	 * required.
3735	 * TODO: Once all related issues will be fixed this situation should be
3736	 * illegal.
3737	 */
3738	if (ee_block != map->m_lblk || ee_len > map->m_len) {
3739#ifdef EXT4_DEBUG
3740		ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3741			     " len %u; IO logical block %llu, len %u\n",
3742			     inode->i_ino, (unsigned long long)ee_block, ee_len,
3743			     (unsigned long long)map->m_lblk, map->m_len);
3744#endif
3745		err = ext4_split_convert_extents(handle, inode, map, ppath,
3746						 EXT4_GET_BLOCKS_CONVERT);
3747		if (err < 0)
3748			return err;
3749		path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3750		if (IS_ERR(path))
3751			return PTR_ERR(path);
3752		depth = ext_depth(inode);
3753		ex = path[depth].p_ext;
3754	}
3755
3756	err = ext4_ext_get_access(handle, inode, path + depth);
3757	if (err)
3758		goto out;
3759	/* first mark the extent as initialized */
3760	ext4_ext_mark_initialized(ex);
3761
3762	/* note: ext4_ext_correct_indexes() isn't needed here because
3763	 * borders are not changed
3764	 */
3765	ext4_ext_try_to_merge(handle, inode, path, ex);
3766
3767	/* Mark modified extent as dirty */
3768	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3769out:
3770	ext4_ext_show_leaf(inode, path);
3771	return err;
3772}
3773
3774static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3775			sector_t block, int count)
3776{
3777	int i;
3778	for (i = 0; i < count; i++)
3779                unmap_underlying_metadata(bdev, block + i);
3780}
3781
3782/*
3783 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3784 */
3785static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3786			      ext4_lblk_t lblk,
3787			      struct ext4_ext_path *path,
3788			      unsigned int len)
3789{
3790	int i, depth;
3791	struct ext4_extent_header *eh;
3792	struct ext4_extent *last_ex;
3793
3794	if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3795		return 0;
3796
3797	depth = ext_depth(inode);
3798	eh = path[depth].p_hdr;
3799
3800	/*
3801	 * We're going to remove EOFBLOCKS_FL entirely in future so we
3802	 * do not care for this case anymore. Simply remove the flag
3803	 * if there are no extents.
3804	 */
3805	if (unlikely(!eh->eh_entries))
3806		goto out;
3807	last_ex = EXT_LAST_EXTENT(eh);
3808	/*
3809	 * We should clear the EOFBLOCKS_FL flag if we are writing the
3810	 * last block in the last extent in the file.  We test this by
3811	 * first checking to see if the caller to
3812	 * ext4_ext_get_blocks() was interested in the last block (or
3813	 * a block beyond the last block) in the current extent.  If
3814	 * this turns out to be false, we can bail out from this
3815	 * function immediately.
3816	 */
3817	if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3818	    ext4_ext_get_actual_len(last_ex))
3819		return 0;
3820	/*
3821	 * If the caller does appear to be planning to write at or
3822	 * beyond the end of the current extent, we then test to see
3823	 * if the current extent is the last extent in the file, by
3824	 * checking to make sure it was reached via the rightmost node
3825	 * at each level of the tree.
3826	 */
3827	for (i = depth-1; i >= 0; i--)
3828		if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3829			return 0;
3830out:
3831	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3832	return ext4_mark_inode_dirty(handle, inode);
3833}
3834
3835/**
3836 * ext4_find_delalloc_range: find delayed allocated block in the given range.
3837 *
3838 * Return 1 if there is a delalloc block in the range, otherwise 0.
3839 */
3840int ext4_find_delalloc_range(struct inode *inode,
3841			     ext4_lblk_t lblk_start,
3842			     ext4_lblk_t lblk_end)
3843{
3844	struct extent_status es;
3845
3846	ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3847	if (es.es_len == 0)
3848		return 0; /* there is no delay extent in this tree */
3849	else if (es.es_lblk <= lblk_start &&
3850		 lblk_start < es.es_lblk + es.es_len)
3851		return 1;
3852	else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3853		return 1;
3854	else
3855		return 0;
3856}
3857
3858int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3859{
3860	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3861	ext4_lblk_t lblk_start, lblk_end;
3862	lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3863	lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3864
3865	return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3866}
3867
3868/**
3869 * Determines how many complete clusters (out of those specified by the 'map')
3870 * are under delalloc and were reserved quota for.
3871 * This function is called when we are writing out the blocks that were
3872 * originally written with their allocation delayed, but then the space was
3873 * allocated using fallocate() before the delayed allocation could be resolved.
3874 * The cases to look for are:
3875 * ('=' indicated delayed allocated blocks
3876 *  '-' indicates non-delayed allocated blocks)
3877 * (a) partial clusters towards beginning and/or end outside of allocated range
3878 *     are not delalloc'ed.
3879 *	Ex:
3880 *	|----c---=|====c====|====c====|===-c----|
3881 *	         |++++++ allocated ++++++|
3882 *	==> 4 complete clusters in above example
3883 *
3884 * (b) partial cluster (outside of allocated range) towards either end is
3885 *     marked for delayed allocation. In this case, we will exclude that
3886 *     cluster.
3887 *	Ex:
3888 *	|----====c========|========c========|
3889 *	     |++++++ allocated ++++++|
3890 *	==> 1 complete clusters in above example
3891 *
3892 *	Ex:
3893 *	|================c================|
3894 *            |++++++ allocated ++++++|
3895 *	==> 0 complete clusters in above example
3896 *
3897 * The ext4_da_update_reserve_space will be called only if we
3898 * determine here that there were some "entire" clusters that span
3899 * this 'allocated' range.
3900 * In the non-bigalloc case, this function will just end up returning num_blks
3901 * without ever calling ext4_find_delalloc_range.
3902 */
3903static unsigned int
3904get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3905			   unsigned int num_blks)
3906{
3907	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3908	ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3909	ext4_lblk_t lblk_from, lblk_to, c_offset;
3910	unsigned int allocated_clusters = 0;
3911
3912	alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3913	alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3914
3915	/* max possible clusters for this allocation */
3916	allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3917
3918	trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3919
3920	/* Check towards left side */
3921	c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3922	if (c_offset) {
3923		lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3924		lblk_to = lblk_from + c_offset - 1;
3925
3926		if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3927			allocated_clusters--;
3928	}
3929
3930	/* Now check towards right. */
3931	c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3932	if (allocated_clusters && c_offset) {
3933		lblk_from = lblk_start + num_blks;
3934		lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3935
3936		if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3937			allocated_clusters--;
3938	}
3939
3940	return allocated_clusters;
3941}
3942
3943static int
3944convert_initialized_extent(handle_t *handle, struct inode *inode,
3945			   struct ext4_map_blocks *map,
3946			   struct ext4_ext_path **ppath,
3947			   unsigned int allocated)
3948{
3949	struct ext4_ext_path *path = *ppath;
3950	struct ext4_extent *ex;
3951	ext4_lblk_t ee_block;
3952	unsigned int ee_len;
3953	int depth;
3954	int err = 0;
3955
3956	/*
3957	 * Make sure that the extent is no bigger than we support with
3958	 * unwritten extent
3959	 */
3960	if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3961		map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3962
3963	depth = ext_depth(inode);
3964	ex = path[depth].p_ext;
3965	ee_block = le32_to_cpu(ex->ee_block);
3966	ee_len = ext4_ext_get_actual_len(ex);
3967
3968	ext_debug("%s: inode %lu, logical"
3969		"block %llu, max_blocks %u\n", __func__, inode->i_ino,
3970		  (unsigned long long)ee_block, ee_len);
3971
3972	if (ee_block != map->m_lblk || ee_len > map->m_len) {
3973		err = ext4_split_convert_extents(handle, inode, map, ppath,
3974				EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3975		if (err < 0)
3976			return err;
3977		path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3978		if (IS_ERR(path))
3979			return PTR_ERR(path);
3980		depth = ext_depth(inode);
3981		ex = path[depth].p_ext;
3982		if (!ex) {
3983			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3984					 (unsigned long) map->m_lblk);
3985			return -EFSCORRUPTED;
3986		}
3987	}
3988
3989	err = ext4_ext_get_access(handle, inode, path + depth);
3990	if (err)
3991		return err;
3992	/* first mark the extent as unwritten */
3993	ext4_ext_mark_unwritten(ex);
3994
3995	/* note: ext4_ext_correct_indexes() isn't needed here because
3996	 * borders are not changed
3997	 */
3998	ext4_ext_try_to_merge(handle, inode, path, ex);
3999
4000	/* Mark modified extent as dirty */
4001	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4002	if (err)
4003		return err;
4004	ext4_ext_show_leaf(inode, path);
4005
4006	ext4_update_inode_fsync_trans(handle, inode, 1);
4007	err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4008	if (err)
4009		return err;
4010	map->m_flags |= EXT4_MAP_UNWRITTEN;
4011	if (allocated > map->m_len)
4012		allocated = map->m_len;
4013	map->m_len = allocated;
4014	return allocated;
4015}
4016
4017static int
4018ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4019			struct ext4_map_blocks *map,
4020			struct ext4_ext_path **ppath, int flags,
4021			unsigned int allocated, ext4_fsblk_t newblock)
4022{
4023	struct ext4_ext_path *path = *ppath;
4024	int ret = 0;
4025	int err = 0;
4026
4027	ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4028		  "block %llu, max_blocks %u, flags %x, allocated %u\n",
4029		  inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4030		  flags, allocated);
4031	ext4_ext_show_leaf(inode, path);
4032
4033	/*
4034	 * When writing into unwritten space, we should not fail to
4035	 * allocate metadata blocks for the new extent block if needed.
4036	 */
4037	flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4038
4039	trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4040						    allocated, newblock);
4041
4042	/* get_block() before submit the IO, split the extent */
4043	if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4044		ret = ext4_split_convert_extents(handle, inode, map, ppath,
4045					 flags | EXT4_GET_BLOCKS_CONVERT);
4046		if (ret <= 0)
4047			goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
4048		map->m_flags |= EXT4_MAP_UNWRITTEN;
4049		goto out;
4050	}
4051	/* IO end_io complete, convert the filled extent to written */
4052	if (flags & EXT4_GET_BLOCKS_CONVERT) {
4053		if (flags & EXT4_GET_BLOCKS_ZERO) {
4054			if (allocated > map->m_len)
4055				allocated = map->m_len;
4056			err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4057						 allocated);
4058			if (err < 0)
4059				goto out2;
4060		}
4061		ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4062							   ppath);
4063		if (ret >= 0) {
4064			ext4_update_inode_fsync_trans(handle, inode, 1);
4065			err = check_eofblocks_fl(handle, inode, map->m_lblk,
4066						 path, map->m_len);
4067		} else
4068			err = ret;
4069		map->m_flags |= EXT4_MAP_MAPPED;
4070		map->m_pblk = newblock;
4071		if (allocated > map->m_len)
4072			allocated = map->m_len;
4073		map->m_len = allocated;
4074		goto out2;
4075	}
4076	/* buffered IO case */
4077	/*
4078	 * repeat fallocate creation request
4079	 * we already have an unwritten extent
4080	 */
4081	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4082		map->m_flags |= EXT4_MAP_UNWRITTEN;
4083		goto map_out;
4084	}
4085
4086	/* buffered READ or buffered write_begin() lookup */
4087	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4088		/*
4089		 * We have blocks reserved already.  We
4090		 * return allocated blocks so that delalloc
4091		 * won't do block reservation for us.  But
4092		 * the buffer head will be unmapped so that
4093		 * a read from the block returns 0s.
4094		 */
4095		map->m_flags |= EXT4_MAP_UNWRITTEN;
4096		goto out1;
4097	}
4098
4099	/* buffered write, writepage time, convert*/
 
 
 
 
4100	ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4101	if (ret >= 0)
4102		ext4_update_inode_fsync_trans(handle, inode, 1);
4103out:
4104	if (ret <= 0) {
4105		err = ret;
4106		goto out2;
4107	} else
4108		allocated = ret;
4109	map->m_flags |= EXT4_MAP_NEW;
4110	/*
4111	 * if we allocated more blocks than requested
4112	 * we need to make sure we unmap the extra block
4113	 * allocated. The actual needed block will get
4114	 * unmapped later when we find the buffer_head marked
4115	 * new.
4116	 */
4117	if (allocated > map->m_len) {
4118		unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4119					newblock + map->m_len,
4120					allocated - map->m_len);
4121		allocated = map->m_len;
4122	}
4123	map->m_len = allocated;
4124
4125	/*
4126	 * If we have done fallocate with the offset that is already
4127	 * delayed allocated, we would have block reservation
4128	 * and quota reservation done in the delayed write path.
4129	 * But fallocate would have already updated quota and block
4130	 * count for this offset. So cancel these reservation
4131	 */
4132	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4133		unsigned int reserved_clusters;
4134		reserved_clusters = get_reserved_cluster_alloc(inode,
4135				map->m_lblk, map->m_len);
4136		if (reserved_clusters)
4137			ext4_da_update_reserve_space(inode,
4138						     reserved_clusters,
4139						     0);
4140	}
4141
 
 
 
4142map_out:
4143	map->m_flags |= EXT4_MAP_MAPPED;
4144	if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4145		err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4146					 map->m_len);
4147		if (err < 0)
4148			goto out2;
4149	}
4150out1:
 
4151	if (allocated > map->m_len)
4152		allocated = map->m_len;
4153	ext4_ext_show_leaf(inode, path);
4154	map->m_pblk = newblock;
4155	map->m_len = allocated;
 
4156out2:
4157	return err ? err : allocated;
4158}
4159
4160/*
4161 * get_implied_cluster_alloc - check to see if the requested
4162 * allocation (in the map structure) overlaps with a cluster already
4163 * allocated in an extent.
4164 *	@sb	The filesystem superblock structure
4165 *	@map	The requested lblk->pblk mapping
4166 *	@ex	The extent structure which might contain an implied
4167 *			cluster allocation
4168 *
4169 * This function is called by ext4_ext_map_blocks() after we failed to
4170 * find blocks that were already in the inode's extent tree.  Hence,
4171 * we know that the beginning of the requested region cannot overlap
4172 * the extent from the inode's extent tree.  There are three cases we
4173 * want to catch.  The first is this case:
4174 *
4175 *		 |--- cluster # N--|
4176 *    |--- extent ---|	|---- requested region ---|
4177 *			|==========|
4178 *
4179 * The second case that we need to test for is this one:
4180 *
4181 *   |--------- cluster # N ----------------|
4182 *	   |--- requested region --|   |------- extent ----|
4183 *	   |=======================|
4184 *
4185 * The third case is when the requested region lies between two extents
4186 * within the same cluster:
4187 *          |------------- cluster # N-------------|
4188 * |----- ex -----|                  |---- ex_right ----|
4189 *                  |------ requested region ------|
4190 *                  |================|
4191 *
4192 * In each of the above cases, we need to set the map->m_pblk and
4193 * map->m_len so it corresponds to the return the extent labelled as
4194 * "|====|" from cluster #N, since it is already in use for data in
4195 * cluster EXT4_B2C(sbi, map->m_lblk).	We will then return 1 to
4196 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4197 * as a new "allocated" block region.  Otherwise, we will return 0 and
4198 * ext4_ext_map_blocks() will then allocate one or more new clusters
4199 * by calling ext4_mb_new_blocks().
4200 */
4201static int get_implied_cluster_alloc(struct super_block *sb,
4202				     struct ext4_map_blocks *map,
4203				     struct ext4_extent *ex,
4204				     struct ext4_ext_path *path)
4205{
4206	struct ext4_sb_info *sbi = EXT4_SB(sb);
4207	ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4208	ext4_lblk_t ex_cluster_start, ex_cluster_end;
4209	ext4_lblk_t rr_cluster_start;
4210	ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4211	ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4212	unsigned short ee_len = ext4_ext_get_actual_len(ex);
4213
4214	/* The extent passed in that we are trying to match */
4215	ex_cluster_start = EXT4_B2C(sbi, ee_block);
4216	ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4217
4218	/* The requested region passed into ext4_map_blocks() */
4219	rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4220
4221	if ((rr_cluster_start == ex_cluster_end) ||
4222	    (rr_cluster_start == ex_cluster_start)) {
4223		if (rr_cluster_start == ex_cluster_end)
4224			ee_start += ee_len - 1;
4225		map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4226		map->m_len = min(map->m_len,
4227				 (unsigned) sbi->s_cluster_ratio - c_offset);
4228		/*
4229		 * Check for and handle this case:
4230		 *
4231		 *   |--------- cluster # N-------------|
4232		 *		       |------- extent ----|
4233		 *	   |--- requested region ---|
4234		 *	   |===========|
4235		 */
4236
4237		if (map->m_lblk < ee_block)
4238			map->m_len = min(map->m_len, ee_block - map->m_lblk);
4239
4240		/*
4241		 * Check for the case where there is already another allocated
4242		 * block to the right of 'ex' but before the end of the cluster.
4243		 *
4244		 *          |------------- cluster # N-------------|
4245		 * |----- ex -----|                  |---- ex_right ----|
4246		 *                  |------ requested region ------|
4247		 *                  |================|
4248		 */
4249		if (map->m_lblk > ee_block) {
4250			ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4251			map->m_len = min(map->m_len, next - map->m_lblk);
4252		}
4253
4254		trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4255		return 1;
4256	}
4257
4258	trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4259	return 0;
4260}
4261
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4262
4263/*
4264 * Block allocation/map/preallocation routine for extents based files
4265 *
4266 *
4267 * Need to be called with
4268 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4269 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4270 *
4271 * return > 0, number of of blocks already mapped/allocated
4272 *          if create == 0 and these are pre-allocated blocks
4273 *          	buffer head is unmapped
4274 *          otherwise blocks are mapped
4275 *
4276 * return = 0, if plain look up failed (blocks have not been allocated)
4277 *          buffer head is unmapped
4278 *
4279 * return < 0, error case.
4280 */
4281int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4282			struct ext4_map_blocks *map, int flags)
4283{
4284	struct ext4_ext_path *path = NULL;
4285	struct ext4_extent newex, *ex, *ex2;
4286	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4287	ext4_fsblk_t newblock = 0;
4288	int free_on_err = 0, err = 0, depth, ret;
4289	unsigned int allocated = 0, offset = 0;
4290	unsigned int allocated_clusters = 0;
4291	struct ext4_allocation_request ar;
4292	ext4_lblk_t cluster_offset;
4293	bool map_from_cluster = false;
4294
4295	ext_debug("blocks %u/%u requested for inode %lu\n",
4296		  map->m_lblk, map->m_len, inode->i_ino);
4297	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4298
4299	/* find extent for this block */
4300	path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4301	if (IS_ERR(path)) {
4302		err = PTR_ERR(path);
4303		path = NULL;
4304		goto out2;
4305	}
4306
4307	depth = ext_depth(inode);
4308
4309	/*
4310	 * consistent leaf must not be empty;
4311	 * this situation is possible, though, _during_ tree modification;
4312	 * this is why assert can't be put in ext4_find_extent()
4313	 */
4314	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4315		EXT4_ERROR_INODE(inode, "bad extent address "
4316				 "lblock: %lu, depth: %d pblock %lld",
4317				 (unsigned long) map->m_lblk, depth,
4318				 path[depth].p_block);
4319		err = -EFSCORRUPTED;
4320		goto out2;
4321	}
4322
4323	ex = path[depth].p_ext;
4324	if (ex) {
4325		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4326		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4327		unsigned short ee_len;
4328
4329
4330		/*
4331		 * unwritten extents are treated as holes, except that
4332		 * we split out initialized portions during a write.
4333		 */
4334		ee_len = ext4_ext_get_actual_len(ex);
4335
4336		trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4337
4338		/* if found extent covers block, simply return it */
4339		if (in_range(map->m_lblk, ee_block, ee_len)) {
4340			newblock = map->m_lblk - ee_block + ee_start;
4341			/* number of remaining blocks in the extent */
4342			allocated = ee_len - (map->m_lblk - ee_block);
4343			ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4344				  ee_block, ee_len, newblock);
4345
4346			/*
4347			 * If the extent is initialized check whether the
4348			 * caller wants to convert it to unwritten.
4349			 */
4350			if ((!ext4_ext_is_unwritten(ex)) &&
4351			    (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4352				allocated = convert_initialized_extent(
4353						handle, inode, map, &path,
4354						allocated);
4355				goto out2;
4356			} else if (!ext4_ext_is_unwritten(ex))
 
 
 
 
 
4357				goto out;
 
4358
4359			ret = ext4_ext_handle_unwritten_extents(
4360				handle, inode, map, &path, flags,
4361				allocated, newblock);
4362			if (ret < 0)
4363				err = ret;
4364			else
4365				allocated = ret;
4366			goto out2;
4367		}
4368	}
4369
4370	/*
4371	 * requested block isn't allocated yet;
4372	 * we couldn't try to create block if create flag is zero
4373	 */
4374	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4375		ext4_lblk_t hole_start, hole_len;
4376
4377		hole_start = map->m_lblk;
4378		hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4379		/*
4380		 * put just found gap into cache to speed up
4381		 * subsequent requests
4382		 */
4383		ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4384
4385		/* Update hole_len to reflect hole size after map->m_lblk */
4386		if (hole_start != map->m_lblk)
4387			hole_len -= map->m_lblk - hole_start;
4388		map->m_pblk = 0;
4389		map->m_len = min_t(unsigned int, map->m_len, hole_len);
4390
4391		goto out2;
4392	}
4393
4394	/*
4395	 * Okay, we need to do block allocation.
4396	 */
4397	newex.ee_block = cpu_to_le32(map->m_lblk);
4398	cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4399
4400	/*
4401	 * If we are doing bigalloc, check to see if the extent returned
4402	 * by ext4_find_extent() implies a cluster we can use.
4403	 */
4404	if (cluster_offset && ex &&
4405	    get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4406		ar.len = allocated = map->m_len;
4407		newblock = map->m_pblk;
4408		map_from_cluster = true;
4409		goto got_allocated_blocks;
4410	}
4411
4412	/* find neighbour allocated blocks */
4413	ar.lleft = map->m_lblk;
4414	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4415	if (err)
4416		goto out2;
4417	ar.lright = map->m_lblk;
4418	ex2 = NULL;
4419	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4420	if (err)
4421		goto out2;
4422
4423	/* Check if the extent after searching to the right implies a
4424	 * cluster we can use. */
4425	if ((sbi->s_cluster_ratio > 1) && ex2 &&
4426	    get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4427		ar.len = allocated = map->m_len;
4428		newblock = map->m_pblk;
4429		map_from_cluster = true;
4430		goto got_allocated_blocks;
4431	}
4432
4433	/*
4434	 * See if request is beyond maximum number of blocks we can have in
4435	 * a single extent. For an initialized extent this limit is
4436	 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4437	 * EXT_UNWRITTEN_MAX_LEN.
4438	 */
4439	if (map->m_len > EXT_INIT_MAX_LEN &&
4440	    !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4441		map->m_len = EXT_INIT_MAX_LEN;
4442	else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4443		 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4444		map->m_len = EXT_UNWRITTEN_MAX_LEN;
4445
4446	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4447	newex.ee_len = cpu_to_le16(map->m_len);
4448	err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4449	if (err)
4450		allocated = ext4_ext_get_actual_len(&newex);
4451	else
4452		allocated = map->m_len;
4453
4454	/* allocate new block */
4455	ar.inode = inode;
4456	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4457	ar.logical = map->m_lblk;
4458	/*
4459	 * We calculate the offset from the beginning of the cluster
4460	 * for the logical block number, since when we allocate a
4461	 * physical cluster, the physical block should start at the
4462	 * same offset from the beginning of the cluster.  This is
4463	 * needed so that future calls to get_implied_cluster_alloc()
4464	 * work correctly.
4465	 */
4466	offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4467	ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4468	ar.goal -= offset;
4469	ar.logical -= offset;
4470	if (S_ISREG(inode->i_mode))
4471		ar.flags = EXT4_MB_HINT_DATA;
4472	else
4473		/* disable in-core preallocation for non-regular files */
4474		ar.flags = 0;
4475	if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4476		ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4477	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4478		ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4479	if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4480		ar.flags |= EXT4_MB_USE_RESERVED;
4481	newblock = ext4_mb_new_blocks(handle, &ar, &err);
4482	if (!newblock)
4483		goto out2;
4484	ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4485		  ar.goal, newblock, allocated);
4486	free_on_err = 1;
4487	allocated_clusters = ar.len;
4488	ar.len = EXT4_C2B(sbi, ar.len) - offset;
 
 
4489	if (ar.len > allocated)
4490		ar.len = allocated;
4491
4492got_allocated_blocks:
4493	/* try to insert new extent into found leaf and return */
4494	ext4_ext_store_pblock(&newex, newblock + offset);
 
4495	newex.ee_len = cpu_to_le16(ar.len);
4496	/* Mark unwritten */
4497	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4498		ext4_ext_mark_unwritten(&newex);
4499		map->m_flags |= EXT4_MAP_UNWRITTEN;
4500	}
4501
4502	err = 0;
4503	if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4504		err = check_eofblocks_fl(handle, inode, map->m_lblk,
4505					 path, ar.len);
4506	if (!err)
4507		err = ext4_ext_insert_extent(handle, inode, &path,
4508					     &newex, flags);
4509
4510	if (err && free_on_err) {
4511		int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4512			EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4513		/* free data blocks we just allocated */
4514		/* not a good idea to call discard here directly,
4515		 * but otherwise we'd need to call it every free() */
4516		ext4_discard_preallocations(inode);
4517		ext4_free_blocks(handle, inode, NULL, newblock,
4518				 EXT4_C2B(sbi, allocated_clusters), fb_flags);
4519		goto out2;
4520	}
4521
4522	/* previous routine could use block we allocated */
4523	newblock = ext4_ext_pblock(&newex);
4524	allocated = ext4_ext_get_actual_len(&newex);
4525	if (allocated > map->m_len)
4526		allocated = map->m_len;
4527	map->m_flags |= EXT4_MAP_NEW;
 
 
 
 
 
 
 
 
4528
4529	/*
4530	 * Update reserved blocks/metadata blocks after successful
4531	 * block allocation which had been deferred till now.
 
 
4532	 */
4533	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4534		unsigned int reserved_clusters;
4535		/*
4536		 * Check how many clusters we had reserved this allocated range
4537		 */
4538		reserved_clusters = get_reserved_cluster_alloc(inode,
4539						map->m_lblk, allocated);
4540		if (!map_from_cluster) {
4541			BUG_ON(allocated_clusters < reserved_clusters);
4542			if (reserved_clusters < allocated_clusters) {
4543				struct ext4_inode_info *ei = EXT4_I(inode);
4544				int reservation = allocated_clusters -
4545						  reserved_clusters;
4546				/*
4547				 * It seems we claimed few clusters outside of
4548				 * the range of this allocation. We should give
4549				 * it back to the reservation pool. This can
4550				 * happen in the following case:
4551				 *
4552				 * * Suppose s_cluster_ratio is 4 (i.e., each
4553				 *   cluster has 4 blocks. Thus, the clusters
4554				 *   are [0-3],[4-7],[8-11]...
4555				 * * First comes delayed allocation write for
4556				 *   logical blocks 10 & 11. Since there were no
4557				 *   previous delayed allocated blocks in the
4558				 *   range [8-11], we would reserve 1 cluster
4559				 *   for this write.
4560				 * * Next comes write for logical blocks 3 to 8.
4561				 *   In this case, we will reserve 2 clusters
4562				 *   (for [0-3] and [4-7]; and not for [8-11] as
4563				 *   that range has a delayed allocated blocks.
4564				 *   Thus total reserved clusters now becomes 3.
4565				 * * Now, during the delayed allocation writeout
4566				 *   time, we will first write blocks [3-8] and
4567				 *   allocate 3 clusters for writing these
4568				 *   blocks. Also, we would claim all these
4569				 *   three clusters above.
4570				 * * Now when we come here to writeout the
4571				 *   blocks [10-11], we would expect to claim
4572				 *   the reservation of 1 cluster we had made
4573				 *   (and we would claim it since there are no
4574				 *   more delayed allocated blocks in the range
4575				 *   [8-11]. But our reserved cluster count had
4576				 *   already gone to 0.
4577				 *
4578				 *   Thus, at the step 4 above when we determine
4579				 *   that there are still some unwritten delayed
4580				 *   allocated blocks outside of our current
4581				 *   block range, we should increment the
4582				 *   reserved clusters count so that when the
4583				 *   remaining blocks finally gets written, we
4584				 *   could claim them.
4585				 */
4586				dquot_reserve_block(inode,
4587						EXT4_C2B(sbi, reservation));
4588				spin_lock(&ei->i_block_reservation_lock);
4589				ei->i_reserved_data_blocks += reservation;
4590				spin_unlock(&ei->i_block_reservation_lock);
4591			}
4592			/*
4593			 * We will claim quota for all newly allocated blocks.
4594			 * We're updating the reserved space *after* the
4595			 * correction above so we do not accidentally free
4596			 * all the metadata reservation because we might
4597			 * actually need it later on.
4598			 */
4599			ext4_da_update_reserve_space(inode, allocated_clusters,
4600							1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4601		}
4602	}
4603
4604	/*
4605	 * Cache the extent and update transaction to commit on fdatasync only
4606	 * when it is _not_ an unwritten extent.
4607	 */
4608	if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4609		ext4_update_inode_fsync_trans(handle, inode, 1);
4610	else
4611		ext4_update_inode_fsync_trans(handle, inode, 0);
4612out:
4613	if (allocated > map->m_len)
4614		allocated = map->m_len;
 
 
4615	ext4_ext_show_leaf(inode, path);
4616	map->m_flags |= EXT4_MAP_MAPPED;
4617	map->m_pblk = newblock;
4618	map->m_len = allocated;
4619out2:
4620	ext4_ext_drop_refs(path);
4621	kfree(path);
4622
4623	trace_ext4_ext_map_blocks_exit(inode, flags, map,
4624				       err ? err : allocated);
4625	return err ? err : allocated;
4626}
4627
4628void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4629{
4630	struct super_block *sb = inode->i_sb;
4631	ext4_lblk_t last_block;
4632	int err = 0;
4633
4634	/*
4635	 * TODO: optimization is possible here.
4636	 * Probably we need not scan at all,
4637	 * because page truncation is enough.
4638	 */
4639
4640	/* we have to know where to truncate from in crash case */
4641	EXT4_I(inode)->i_disksize = inode->i_size;
4642	ext4_mark_inode_dirty(handle, inode);
 
 
4643
4644	last_block = (inode->i_size + sb->s_blocksize - 1)
4645			>> EXT4_BLOCK_SIZE_BITS(sb);
4646retry:
4647	err = ext4_es_remove_extent(inode, last_block,
4648				    EXT_MAX_BLOCKS - last_block);
 
4649	if (err == -ENOMEM) {
4650		cond_resched();
4651		congestion_wait(BLK_RW_ASYNC, HZ/50);
4652		goto retry;
4653	}
4654	if (err) {
4655		ext4_std_error(inode->i_sb, err);
4656		return;
4657	}
4658	err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4659	ext4_std_error(inode->i_sb, err);
4660}
4661
4662static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4663				  ext4_lblk_t len, loff_t new_size,
4664				  int flags, int mode)
4665{
4666	struct inode *inode = file_inode(file);
4667	handle_t *handle;
4668	int ret = 0;
4669	int ret2 = 0;
4670	int retries = 0;
4671	int depth = 0;
4672	struct ext4_map_blocks map;
4673	unsigned int credits;
4674	loff_t epos;
4675
 
4676	map.m_lblk = offset;
4677	map.m_len = len;
4678	/*
4679	 * Don't normalize the request if it can fit in one extent so
4680	 * that it doesn't get unnecessarily split into multiple
4681	 * extents.
4682	 */
4683	if (len <= EXT_UNWRITTEN_MAX_LEN)
4684		flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4685
4686	/*
4687	 * credits to insert 1 extent into extent tree
4688	 */
4689	credits = ext4_chunk_trans_blocks(inode, len);
4690	/*
4691	 * We can only call ext_depth() on extent based inodes
4692	 */
4693	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4694		depth = ext_depth(inode);
4695	else
4696		depth = -1;
4697
4698retry:
4699	while (ret >= 0 && len) {
4700		/*
4701		 * Recalculate credits when extent tree depth changes.
4702		 */
4703		if (depth >= 0 && depth != ext_depth(inode)) {
4704			credits = ext4_chunk_trans_blocks(inode, len);
4705			depth = ext_depth(inode);
4706		}
4707
4708		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4709					    credits);
4710		if (IS_ERR(handle)) {
4711			ret = PTR_ERR(handle);
4712			break;
4713		}
4714		ret = ext4_map_blocks(handle, inode, &map, flags);
4715		if (ret <= 0) {
4716			ext4_debug("inode #%lu: block %u: len %u: "
4717				   "ext4_ext_map_blocks returned %d",
4718				   inode->i_ino, map.m_lblk,
4719				   map.m_len, ret);
4720			ext4_mark_inode_dirty(handle, inode);
4721			ret2 = ext4_journal_stop(handle);
4722			break;
4723		}
 
 
 
 
4724		map.m_lblk += ret;
4725		map.m_len = len = len - ret;
4726		epos = (loff_t)map.m_lblk << inode->i_blkbits;
4727		inode->i_ctime = ext4_current_time(inode);
4728		if (new_size) {
4729			if (epos > new_size)
4730				epos = new_size;
4731			if (ext4_update_inode_size(inode, epos) & 0x1)
4732				inode->i_mtime = inode->i_ctime;
4733		} else {
4734			if (epos > inode->i_size)
4735				ext4_set_inode_flag(inode,
4736						    EXT4_INODE_EOFBLOCKS);
4737		}
4738		ext4_mark_inode_dirty(handle, inode);
4739		ret2 = ext4_journal_stop(handle);
4740		if (ret2)
4741			break;
4742	}
4743	if (ret == -ENOSPC &&
4744			ext4_should_retry_alloc(inode->i_sb, &retries)) {
4745		ret = 0;
4746		goto retry;
4747	}
4748
4749	return ret > 0 ? ret2 : ret;
4750}
4751
 
 
 
 
4752static long ext4_zero_range(struct file *file, loff_t offset,
4753			    loff_t len, int mode)
4754{
4755	struct inode *inode = file_inode(file);
 
4756	handle_t *handle = NULL;
4757	unsigned int max_blocks;
4758	loff_t new_size = 0;
4759	int ret = 0;
4760	int flags;
4761	int credits;
4762	int partial_begin, partial_end;
4763	loff_t start, end;
4764	ext4_lblk_t lblk;
4765	unsigned int blkbits = inode->i_blkbits;
4766
4767	trace_ext4_zero_range(inode, offset, len, mode);
4768
4769	if (!S_ISREG(inode->i_mode))
4770		return -EINVAL;
4771
4772	/* Call ext4_force_commit to flush all data in case of data=journal. */
4773	if (ext4_should_journal_data(inode)) {
4774		ret = ext4_force_commit(inode->i_sb);
4775		if (ret)
4776			return ret;
4777	}
4778
4779	/*
4780	 * Round up offset. This is not fallocate, we neet to zero out
4781	 * blocks, so convert interior block aligned part of the range to
4782	 * unwritten and possibly manually zero out unaligned parts of the
4783	 * range.
 
4784	 */
4785	start = round_up(offset, 1 << blkbits);
4786	end = round_down((offset + len), 1 << blkbits);
4787
4788	if (start < offset || end > offset + len)
4789		return -EINVAL;
4790	partial_begin = offset & ((1 << blkbits) - 1);
4791	partial_end = (offset + len) & ((1 << blkbits) - 1);
4792
4793	lblk = start >> blkbits;
4794	max_blocks = (end >> blkbits);
4795	if (max_blocks < lblk)
4796		max_blocks = 0;
4797	else
4798		max_blocks -= lblk;
4799
4800	inode_lock(inode);
4801
4802	/*
4803	 * Indirect files do not support unwritten extnets
4804	 */
4805	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4806		ret = -EOPNOTSUPP;
4807		goto out_mutex;
4808	}
4809
4810	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4811	     offset + len > i_size_read(inode)) {
 
4812		new_size = offset + len;
4813		ret = inode_newsize_ok(inode, new_size);
4814		if (ret)
4815			goto out_mutex;
4816	}
4817
4818	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4819	if (mode & FALLOC_FL_KEEP_SIZE)
4820		flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4821
4822	/* Wait all existing dio workers, newcomers will block on i_mutex */
4823	ext4_inode_block_unlocked_dio(inode);
4824	inode_dio_wait(inode);
4825
 
 
 
 
4826	/* Preallocate the range including the unaligned edges */
4827	if (partial_begin || partial_end) {
4828		ret = ext4_alloc_file_blocks(file,
4829				round_down(offset, 1 << blkbits) >> blkbits,
4830				(round_up((offset + len), 1 << blkbits) -
4831				 round_down(offset, 1 << blkbits)) >> blkbits,
4832				new_size, flags, mode);
4833		if (ret)
4834			goto out_dio;
4835
4836	}
4837
4838	/* Zero range excluding the unaligned edges */
4839	if (max_blocks > 0) {
4840		flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4841			  EXT4_EX_NOCACHE);
4842
4843		/*
4844		 * Prevent page faults from reinstantiating pages we have
4845		 * released from page cache.
4846		 */
4847		down_write(&EXT4_I(inode)->i_mmap_sem);
 
 
 
 
 
 
 
4848		ret = ext4_update_disksize_before_punch(inode, offset, len);
4849		if (ret) {
4850			up_write(&EXT4_I(inode)->i_mmap_sem);
4851			goto out_dio;
4852		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4853		/* Now release the pages and zero block aligned part of pages */
4854		truncate_pagecache_range(inode, start, end - 1);
4855		inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4856
4857		ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4858					     flags, mode);
4859		up_write(&EXT4_I(inode)->i_mmap_sem);
4860		if (ret)
4861			goto out_dio;
4862	}
4863	if (!partial_begin && !partial_end)
4864		goto out_dio;
4865
4866	/*
4867	 * In worst case we have to writeout two nonadjacent unwritten
4868	 * blocks and update the inode
4869	 */
4870	credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4871	if (ext4_should_journal_data(inode))
4872		credits += 2;
4873	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4874	if (IS_ERR(handle)) {
4875		ret = PTR_ERR(handle);
4876		ext4_std_error(inode->i_sb, ret);
4877		goto out_dio;
4878	}
4879
4880	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4881	if (new_size) {
4882		ext4_update_inode_size(inode, new_size);
4883	} else {
4884		/*
4885		* Mark that we allocate beyond EOF so the subsequent truncate
4886		* can proceed even if the new size is the same as i_size.
4887		*/
4888		if ((offset + len) > i_size_read(inode))
4889			ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4890	}
4891	ext4_mark_inode_dirty(handle, inode);
4892
4893	/* Zero out partial block at the edges of the range */
4894	ret = ext4_zero_partial_blocks(handle, inode, offset, len);
 
 
4895
4896	if (file->f_flags & O_SYNC)
4897		ext4_handle_sync(handle);
4898
 
4899	ext4_journal_stop(handle);
4900out_dio:
4901	ext4_inode_resume_unlocked_dio(inode);
4902out_mutex:
4903	inode_unlock(inode);
4904	return ret;
4905}
4906
4907/*
4908 * preallocate space for a file. This implements ext4's fallocate file
4909 * operation, which gets called from sys_fallocate system call.
4910 * For block-mapped files, posix_fallocate should fall back to the method
4911 * of writing zeroes to the required new blocks (the same behavior which is
4912 * expected for file systems which do not support fallocate() system call).
4913 */
4914long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4915{
4916	struct inode *inode = file_inode(file);
4917	loff_t new_size = 0;
4918	unsigned int max_blocks;
4919	int ret = 0;
4920	int flags;
4921	ext4_lblk_t lblk;
4922	unsigned int blkbits = inode->i_blkbits;
4923
4924	/*
4925	 * Encrypted inodes can't handle collapse range or insert
4926	 * range since we would need to re-encrypt blocks with a
4927	 * different IV or XTS tweak (which are based on the logical
4928	 * block number).
4929	 *
4930	 * XXX It's not clear why zero range isn't working, but we'll
4931	 * leave it disabled for encrypted inodes for now.  This is a
4932	 * bug we should fix....
4933	 */
4934	if (ext4_encrypted_inode(inode) &&
4935	    (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4936		     FALLOC_FL_ZERO_RANGE)))
4937		return -EOPNOTSUPP;
4938
4939	/* Return error if mode is not supported */
4940	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4941		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4942		     FALLOC_FL_INSERT_RANGE))
4943		return -EOPNOTSUPP;
4944
4945	if (mode & FALLOC_FL_PUNCH_HOLE)
4946		return ext4_punch_hole(inode, offset, len);
4947
4948	ret = ext4_convert_inline_data(inode);
 
4949	if (ret)
4950		return ret;
4951
4952	if (mode & FALLOC_FL_COLLAPSE_RANGE)
4953		return ext4_collapse_range(inode, offset, len);
 
 
4954
4955	if (mode & FALLOC_FL_INSERT_RANGE)
4956		return ext4_insert_range(inode, offset, len);
 
 
4957
4958	if (mode & FALLOC_FL_ZERO_RANGE)
4959		return ext4_zero_range(file, offset, len, mode);
 
 
4960
 
 
 
 
4961	trace_ext4_fallocate_enter(inode, offset, len, mode);
4962	lblk = offset >> blkbits;
4963	/*
4964	 * We can't just convert len to max_blocks because
4965	 * If blocksize = 4096 offset = 3072 and len = 2048
4966	 */
4967	max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4968		- lblk;
4969
 
4970	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4971	if (mode & FALLOC_FL_KEEP_SIZE)
4972		flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4973
4974	inode_lock(inode);
4975
4976	/*
4977	 * We only support preallocation for extent-based files only
4978	 */
4979	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4980		ret = -EOPNOTSUPP;
4981		goto out;
4982	}
4983
4984	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4985	     offset + len > i_size_read(inode)) {
 
4986		new_size = offset + len;
4987		ret = inode_newsize_ok(inode, new_size);
4988		if (ret)
4989			goto out;
4990	}
4991
4992	/* Wait all existing dio workers, newcomers will block on i_mutex */
4993	ext4_inode_block_unlocked_dio(inode);
4994	inode_dio_wait(inode);
4995
4996	ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4997				     flags, mode);
4998	ext4_inode_resume_unlocked_dio(inode);
 
 
4999	if (ret)
5000		goto out;
5001
5002	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
5003		ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5004						EXT4_I(inode)->i_sync_tid);
5005	}
5006out:
5007	inode_unlock(inode);
5008	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
 
5009	return ret;
5010}
5011
5012/*
5013 * This function convert a range of blocks to written extents
5014 * The caller of this function will pass the start offset and the size.
5015 * all unwritten extents within this range will be converted to
5016 * written extents.
5017 *
5018 * This function is called from the direct IO end io call back
5019 * function, to convert the fallocated extents after IO is completed.
5020 * Returns 0 on success.
5021 */
5022int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5023				   loff_t offset, ssize_t len)
5024{
5025	unsigned int max_blocks;
5026	int ret = 0;
5027	int ret2 = 0;
5028	struct ext4_map_blocks map;
5029	unsigned int credits, blkbits = inode->i_blkbits;
 
5030
5031	map.m_lblk = offset >> blkbits;
5032	/*
5033	 * We can't just convert len to max_blocks because
5034	 * If blocksize = 4096 offset = 3072 and len = 2048
5035	 */
5036	max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5037		      map.m_lblk);
5038	/*
5039	 * This is somewhat ugly but the idea is clear: When transaction is
5040	 * reserved, everything goes into it. Otherwise we rather start several
5041	 * smaller transactions for conversion of each extent separately.
5042	 */
5043	if (handle) {
5044		handle = ext4_journal_start_reserved(handle,
5045						     EXT4_HT_EXT_CONVERT);
5046		if (IS_ERR(handle))
5047			return PTR_ERR(handle);
5048		credits = 0;
5049	} else {
5050		/*
5051		 * credits to insert 1 extent into extent tree
5052		 */
5053		credits = ext4_chunk_trans_blocks(inode, max_blocks);
5054	}
5055	while (ret >= 0 && ret < max_blocks) {
5056		map.m_lblk += ret;
5057		map.m_len = (max_blocks -= ret);
5058		if (credits) {
5059			handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5060						    credits);
5061			if (IS_ERR(handle)) {
5062				ret = PTR_ERR(handle);
5063				break;
5064			}
5065		}
5066		ret = ext4_map_blocks(handle, inode, &map,
5067				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5068		if (ret <= 0)
5069			ext4_warning(inode->i_sb,
5070				     "inode #%lu: block %u: len %u: "
5071				     "ext4_ext_map_blocks returned %d",
5072				     inode->i_ino, map.m_lblk,
5073				     map.m_len, ret);
5074		ext4_mark_inode_dirty(handle, inode);
5075		if (credits)
5076			ret2 = ext4_journal_stop(handle);
 
 
 
 
5077		if (ret <= 0 || ret2)
5078			break;
5079	}
5080	if (!credits)
5081		ret2 = ext4_journal_stop(handle);
5082	return ret > 0 ? ret2 : ret;
5083}
5084
5085/*
5086 * If newes is not existing extent (newes->ec_pblk equals zero) find
5087 * delayed extent at start of newes and update newes accordingly and
5088 * return start of the next delayed extent.
5089 *
5090 * If newes is existing extent (newes->ec_pblk is not equal zero)
5091 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5092 * extent found. Leave newes unmodified.
5093 */
5094static int ext4_find_delayed_extent(struct inode *inode,
5095				    struct extent_status *newes)
5096{
5097	struct extent_status es;
5098	ext4_lblk_t block, next_del;
5099
5100	if (newes->es_pblk == 0) {
5101		ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5102				newes->es_lblk + newes->es_len - 1, &es);
5103
5104		/*
5105		 * No extent in extent-tree contains block @newes->es_pblk,
5106		 * then the block may stay in 1)a hole or 2)delayed-extent.
5107		 */
5108		if (es.es_len == 0)
5109			/* A hole found. */
5110			return 0;
5111
5112		if (es.es_lblk > newes->es_lblk) {
5113			/* A hole found. */
5114			newes->es_len = min(es.es_lblk - newes->es_lblk,
5115					    newes->es_len);
5116			return 0;
5117		}
5118
5119		newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
 
 
 
 
 
5120	}
5121
5122	block = newes->es_lblk + newes->es_len;
5123	ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5124	if (es.es_len == 0)
5125		next_del = EXT_MAX_BLOCKS;
5126	else
5127		next_del = es.es_lblk;
5128
5129	return next_del;
5130}
5131/* fiemap flags we can handle specified here */
5132#define EXT4_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5133
5134static int ext4_xattr_fiemap(struct inode *inode,
5135				struct fiemap_extent_info *fieinfo)
5136{
5137	__u64 physical = 0;
5138	__u64 length;
5139	__u32 flags = FIEMAP_EXTENT_LAST;
5140	int blockbits = inode->i_sb->s_blocksize_bits;
5141	int error = 0;
 
5142
5143	/* in-inode? */
5144	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5145		struct ext4_iloc iloc;
5146		int offset;	/* offset of xattr in inode */
5147
5148		error = ext4_get_inode_loc(inode, &iloc);
5149		if (error)
5150			return error;
5151		physical = (__u64)iloc.bh->b_blocknr << blockbits;
5152		offset = EXT4_GOOD_OLD_INODE_SIZE +
5153				EXT4_I(inode)->i_extra_isize;
5154		physical += offset;
5155		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5156		flags |= FIEMAP_EXTENT_DATA_INLINE;
5157		brelse(iloc.bh);
5158	} else { /* external block */
 
5159		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5160		length = inode->i_sb->s_blocksize;
 
 
 
 
 
5161	}
5162
5163	if (physical)
5164		error = fiemap_fill_next_extent(fieinfo, 0, physical,
5165						length, flags);
5166	return (error < 0 ? error : 0);
 
 
 
5167}
5168
5169int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5170		__u64 start, __u64 len)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5171{
5172	ext4_lblk_t start_blk;
5173	int error = 0;
5174
5175	if (ext4_has_inline_data(inode)) {
5176		int has_inline = 1;
 
 
5177
5178		error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5179						start, len);
 
 
5180
5181		if (has_inline)
5182			return error;
5183	}
 
 
 
 
 
 
 
 
 
5184
5185	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5186		error = ext4_ext_precache(inode);
5187		if (error)
5188			return error;
 
5189	}
5190
5191	/* fallback to generic here if not in extents fmt */
5192	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5193		return generic_block_fiemap(inode, fieinfo, start, len,
5194			ext4_get_block);
5195
5196	if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5197		return -EBADR;
 
5198
5199	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5200		error = ext4_xattr_fiemap(inode, fieinfo);
5201	} else {
5202		ext4_lblk_t len_blks;
5203		__u64 last_blk;
5204
5205		start_blk = start >> inode->i_sb->s_blocksize_bits;
5206		last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5207		if (last_blk >= EXT_MAX_BLOCKS)
5208			last_blk = EXT_MAX_BLOCKS-1;
5209		len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5210
5211		/*
5212		 * Walk the extent tree gathering extent information
5213		 * and pushing extents back to the user.
5214		 */
5215		error = ext4_fill_fiemap_extents(inode, start_blk,
5216						 len_blks, fieinfo);
5217	}
5218	return error;
 
5219}
5220
5221/*
5222 * ext4_access_path:
5223 * Function to access the path buffer for marking it dirty.
5224 * It also checks if there are sufficient credits left in the journal handle
5225 * to update path.
5226 */
5227static int
5228ext4_access_path(handle_t *handle, struct inode *inode,
5229		struct ext4_ext_path *path)
5230{
5231	int credits, err;
 
 
5232
5233	if (!ext4_handle_valid(handle))
5234		return 0;
5235
5236	/*
5237	 * Check if need to extend journal credits
5238	 * 3 for leaf, sb, and inode plus 2 (bmap and group
5239	 * descriptor) for each block group; assume two block
5240	 * groups
5241	 */
5242	if (handle->h_buffer_credits < 7) {
5243		credits = ext4_writepage_trans_blocks(inode);
5244		err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5245		/* EAGAIN is success */
5246		if (err && err != -EAGAIN)
5247			return err;
5248	}
5249
5250	err = ext4_ext_get_access(handle, inode, path);
5251	return err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5252}
5253
5254/*
5255 * ext4_ext_shift_path_extents:
5256 * Shift the extents of a path structure lying between path[depth].p_ext
5257 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5258 * if it is right shift or left shift operation.
5259 */
5260static int
5261ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5262			    struct inode *inode, handle_t *handle,
5263			    enum SHIFT_DIRECTION SHIFT)
5264{
5265	int depth, err = 0;
5266	struct ext4_extent *ex_start, *ex_last;
5267	bool update = 0;
 
5268	depth = path->p_depth;
5269
5270	while (depth >= 0) {
5271		if (depth == path->p_depth) {
5272			ex_start = path[depth].p_ext;
5273			if (!ex_start)
5274				return -EFSCORRUPTED;
5275
5276			ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
 
 
 
 
 
 
 
5277
5278			err = ext4_access_path(handle, inode, path + depth);
5279			if (err)
 
 
 
 
5280				goto out;
 
5281
5282			if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5283				update = 1;
 
5284
5285			while (ex_start <= ex_last) {
5286				if (SHIFT == SHIFT_LEFT) {
5287					le32_add_cpu(&ex_start->ee_block,
5288						-shift);
5289					/* Try to merge to the left. */
5290					if ((ex_start >
5291					    EXT_FIRST_EXTENT(path[depth].p_hdr))
5292					    &&
5293					    ext4_ext_try_to_merge_right(inode,
5294					    path, ex_start - 1))
5295						ex_last--;
5296					else
5297						ex_start++;
5298				} else {
5299					le32_add_cpu(&ex_last->ee_block, shift);
5300					ext4_ext_try_to_merge_right(inode, path,
5301						ex_last);
5302					ex_last--;
5303				}
5304			}
5305			err = ext4_ext_dirty(handle, inode, path + depth);
5306			if (err)
5307				goto out;
5308
5309			if (--depth < 0 || !update)
5310				break;
5311		}
5312
5313		/* Update index too */
5314		err = ext4_access_path(handle, inode, path + depth);
5315		if (err)
5316			goto out;
5317
5318		if (SHIFT == SHIFT_LEFT)
5319			le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5320		else
5321			le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5322		err = ext4_ext_dirty(handle, inode, path + depth);
5323		if (err)
5324			goto out;
5325
5326		/* we are done if current index is not a starting index */
5327		if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5328			break;
5329
5330		depth--;
5331	}
5332
5333out:
5334	return err;
5335}
5336
5337/*
5338 * ext4_ext_shift_extents:
5339 * All the extents which lies in the range from @start to the last allocated
5340 * block for the @inode are shifted either towards left or right (depending
5341 * upon @SHIFT) by @shift blocks.
5342 * On success, 0 is returned, error otherwise.
5343 */
5344static int
5345ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5346		       ext4_lblk_t start, ext4_lblk_t shift,
5347		       enum SHIFT_DIRECTION SHIFT)
5348{
5349	struct ext4_ext_path *path;
5350	int ret = 0, depth;
5351	struct ext4_extent *extent;
5352	ext4_lblk_t stop, *iterator, ex_start, ex_end;
 
5353
5354	/* Let path point to the last extent */
5355	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
 
5356	if (IS_ERR(path))
5357		return PTR_ERR(path);
5358
5359	depth = path->p_depth;
5360	extent = path[depth].p_ext;
5361	if (!extent)
5362		goto out;
5363
5364	stop = le32_to_cpu(extent->ee_block) +
5365			ext4_ext_get_actual_len(extent);
5366
5367       /*
5368	 * In case of left shift, Don't start shifting extents until we make
5369	 * sure the hole is big enough to accommodate the shift.
 
5370	*/
5371	if (SHIFT == SHIFT_LEFT) {
5372		path = ext4_find_extent(inode, start - 1, &path, 0);
 
5373		if (IS_ERR(path))
5374			return PTR_ERR(path);
5375		depth = path->p_depth;
5376		extent =  path[depth].p_ext;
5377		if (extent) {
5378			ex_start = le32_to_cpu(extent->ee_block);
5379			ex_end = le32_to_cpu(extent->ee_block) +
5380				ext4_ext_get_actual_len(extent);
5381		} else {
5382			ex_start = 0;
5383			ex_end = 0;
5384		}
5385
5386		if ((start == ex_start && shift > ex_start) ||
5387		    (shift > start - ex_end)) {
5388			ext4_ext_drop_refs(path);
5389			kfree(path);
5390			return -EINVAL;
 
 
 
 
 
5391		}
5392	}
5393
5394	/*
5395	 * In case of left shift, iterator points to start and it is increased
5396	 * till we reach stop. In case of right shift, iterator points to stop
5397	 * and it is decreased till we reach start.
5398	 */
 
 
5399	if (SHIFT == SHIFT_LEFT)
5400		iterator = &start;
5401	else
5402		iterator = &stop;
5403
5404	/* Its safe to start updating extents */
5405	while (start < stop) {
5406		path = ext4_find_extent(inode, *iterator, &path, 0);
 
 
 
 
 
 
 
 
5407		if (IS_ERR(path))
5408			return PTR_ERR(path);
5409		depth = path->p_depth;
5410		extent = path[depth].p_ext;
5411		if (!extent) {
5412			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5413					 (unsigned long) *iterator);
5414			return -EFSCORRUPTED;
5415		}
5416		if (SHIFT == SHIFT_LEFT && *iterator >
5417		    le32_to_cpu(extent->ee_block)) {
5418			/* Hole, move to the next extent */
5419			if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5420				path[depth].p_ext++;
5421			} else {
5422				*iterator = ext4_ext_next_allocated_block(path);
5423				continue;
5424			}
5425		}
5426
 
5427		if (SHIFT == SHIFT_LEFT) {
5428			extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5429			*iterator = le32_to_cpu(extent->ee_block) +
5430					ext4_ext_get_actual_len(extent);
5431		} else {
5432			extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5433			*iterator =  le32_to_cpu(extent->ee_block) > 0 ?
5434				le32_to_cpu(extent->ee_block) - 1 : 0;
5435			/* Update path extent in case we need to stop */
5436			while (le32_to_cpu(extent->ee_block) < start)
 
 
 
 
 
 
 
 
5437				extent++;
 
 
5438			path[depth].p_ext = extent;
5439		}
5440		ret = ext4_ext_shift_path_extents(path, shift, inode,
5441				handle, SHIFT);
 
 
 
5442		if (ret)
5443			break;
5444	}
5445out:
5446	ext4_ext_drop_refs(path);
5447	kfree(path);
5448	return ret;
5449}
5450
5451/*
5452 * ext4_collapse_range:
5453 * This implements the fallocate's collapse range functionality for ext4
5454 * Returns: 0 and non-zero on error.
5455 */
5456int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5457{
 
5458	struct super_block *sb = inode->i_sb;
 
5459	ext4_lblk_t punch_start, punch_stop;
5460	handle_t *handle;
5461	unsigned int credits;
5462	loff_t new_size, ioffset;
5463	int ret;
5464
5465	/*
5466	 * We need to test this early because xfstests assumes that a
5467	 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5468	 * system does not support collapse range.
5469	 */
5470	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5471		return -EOPNOTSUPP;
5472
5473	/* Collapse range works only on fs block size aligned offsets. */
5474	if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5475	    len & (EXT4_CLUSTER_SIZE(sb) - 1))
5476		return -EINVAL;
5477
5478	if (!S_ISREG(inode->i_mode))
5479		return -EINVAL;
5480
5481	trace_ext4_collapse_range(inode, offset, len);
5482
5483	punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5484	punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5485
5486	/* Call ext4_force_commit to flush all data in case of data=journal. */
5487	if (ext4_should_journal_data(inode)) {
5488		ret = ext4_force_commit(inode->i_sb);
5489		if (ret)
5490			return ret;
5491	}
5492
5493	inode_lock(inode);
5494	/*
5495	 * There is no need to overlap collapse range with EOF, in which case
5496	 * it is effectively a truncate operation
5497	 */
5498	if (offset + len >= i_size_read(inode)) {
5499		ret = -EINVAL;
5500		goto out_mutex;
5501	}
5502
5503	/* Currently just for extent based files */
5504	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5505		ret = -EOPNOTSUPP;
5506		goto out_mutex;
5507	}
5508
5509	/* Wait for existing dio to complete */
5510	ext4_inode_block_unlocked_dio(inode);
5511	inode_dio_wait(inode);
5512
 
 
 
 
5513	/*
5514	 * Prevent page faults from reinstantiating pages we have released from
5515	 * page cache.
5516	 */
5517	down_write(&EXT4_I(inode)->i_mmap_sem);
 
 
 
 
 
5518	/*
5519	 * Need to round down offset to be aligned with page size boundary
5520	 * for page size > block size.
5521	 */
5522	ioffset = round_down(offset, PAGE_SIZE);
5523	/*
5524	 * Write tail of the last page before removed range since it will get
5525	 * removed from the page cache below.
5526	 */
5527	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5528	if (ret)
5529		goto out_mmap;
5530	/*
5531	 * Write data that will be shifted to preserve them when discarding
5532	 * page cache below. We are also protected from pages becoming dirty
5533	 * by i_mmap_sem.
5534	 */
5535	ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5536					   LLONG_MAX);
5537	if (ret)
5538		goto out_mmap;
5539	truncate_pagecache(inode, ioffset);
5540
5541	credits = ext4_writepage_trans_blocks(inode);
5542	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5543	if (IS_ERR(handle)) {
5544		ret = PTR_ERR(handle);
5545		goto out_mmap;
5546	}
 
5547
5548	down_write(&EXT4_I(inode)->i_data_sem);
5549	ext4_discard_preallocations(inode);
5550
5551	ret = ext4_es_remove_extent(inode, punch_start,
5552				    EXT_MAX_BLOCKS - punch_start);
5553	if (ret) {
5554		up_write(&EXT4_I(inode)->i_data_sem);
5555		goto out_stop;
5556	}
5557
5558	ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5559	if (ret) {
5560		up_write(&EXT4_I(inode)->i_data_sem);
5561		goto out_stop;
5562	}
5563	ext4_discard_preallocations(inode);
5564
5565	ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5566				     punch_stop - punch_start, SHIFT_LEFT);
5567	if (ret) {
5568		up_write(&EXT4_I(inode)->i_data_sem);
5569		goto out_stop;
5570	}
5571
5572	new_size = i_size_read(inode) - len;
5573	i_size_write(inode, new_size);
5574	EXT4_I(inode)->i_disksize = new_size;
5575
5576	up_write(&EXT4_I(inode)->i_data_sem);
5577	if (IS_SYNC(inode))
5578		ext4_handle_sync(handle);
5579	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5580	ext4_mark_inode_dirty(handle, inode);
 
5581
5582out_stop:
5583	ext4_journal_stop(handle);
5584out_mmap:
5585	up_write(&EXT4_I(inode)->i_mmap_sem);
5586	ext4_inode_resume_unlocked_dio(inode);
5587out_mutex:
5588	inode_unlock(inode);
5589	return ret;
5590}
5591
5592/*
5593 * ext4_insert_range:
5594 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5595 * The data blocks starting from @offset to the EOF are shifted by @len
5596 * towards right to create a hole in the @inode. Inode size is increased
5597 * by len bytes.
5598 * Returns 0 on success, error otherwise.
5599 */
5600int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5601{
 
5602	struct super_block *sb = inode->i_sb;
 
5603	handle_t *handle;
5604	struct ext4_ext_path *path;
5605	struct ext4_extent *extent;
5606	ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5607	unsigned int credits, ee_len;
5608	int ret = 0, depth, split_flag = 0;
5609	loff_t ioffset;
5610
5611	/*
5612	 * We need to test this early because xfstests assumes that an
5613	 * insert range of (0, 1) will return EOPNOTSUPP if the file
5614	 * system does not support insert range.
5615	 */
5616	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5617		return -EOPNOTSUPP;
5618
5619	/* Insert range works only on fs block size aligned offsets. */
5620	if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5621			len & (EXT4_CLUSTER_SIZE(sb) - 1))
5622		return -EINVAL;
5623
5624	if (!S_ISREG(inode->i_mode))
5625		return -EOPNOTSUPP;
5626
5627	trace_ext4_insert_range(inode, offset, len);
5628
5629	offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5630	len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5631
5632	/* Call ext4_force_commit to flush all data in case of data=journal */
5633	if (ext4_should_journal_data(inode)) {
5634		ret = ext4_force_commit(inode->i_sb);
5635		if (ret)
5636			return ret;
5637	}
5638
5639	inode_lock(inode);
5640	/* Currently just for extent based files */
5641	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5642		ret = -EOPNOTSUPP;
5643		goto out_mutex;
5644	}
5645
5646	/* Check for wrap through zero */
5647	if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5648		ret = -EFBIG;
5649		goto out_mutex;
5650	}
5651
5652	/* Offset should be less than i_size */
5653	if (offset >= i_size_read(inode)) {
5654		ret = -EINVAL;
5655		goto out_mutex;
5656	}
5657
5658	/* Wait for existing dio to complete */
5659	ext4_inode_block_unlocked_dio(inode);
5660	inode_dio_wait(inode);
5661
 
 
 
 
5662	/*
5663	 * Prevent page faults from reinstantiating pages we have released from
5664	 * page cache.
5665	 */
5666	down_write(&EXT4_I(inode)->i_mmap_sem);
 
 
 
 
 
5667	/*
5668	 * Need to round down to align start offset to page size boundary
5669	 * for page size > block size.
5670	 */
5671	ioffset = round_down(offset, PAGE_SIZE);
5672	/* Write out all dirty pages */
5673	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5674			LLONG_MAX);
5675	if (ret)
5676		goto out_mmap;
5677	truncate_pagecache(inode, ioffset);
5678
5679	credits = ext4_writepage_trans_blocks(inode);
5680	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5681	if (IS_ERR(handle)) {
5682		ret = PTR_ERR(handle);
5683		goto out_mmap;
5684	}
 
5685
5686	/* Expand file to avoid data loss if there is error while shifting */
5687	inode->i_size += len;
5688	EXT4_I(inode)->i_disksize += len;
5689	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5690	ret = ext4_mark_inode_dirty(handle, inode);
5691	if (ret)
5692		goto out_stop;
5693
5694	down_write(&EXT4_I(inode)->i_data_sem);
5695	ext4_discard_preallocations(inode);
5696
5697	path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5698	if (IS_ERR(path)) {
5699		up_write(&EXT4_I(inode)->i_data_sem);
5700		goto out_stop;
5701	}
5702
5703	depth = ext_depth(inode);
5704	extent = path[depth].p_ext;
5705	if (extent) {
5706		ee_start_lblk = le32_to_cpu(extent->ee_block);
5707		ee_len = ext4_ext_get_actual_len(extent);
5708
5709		/*
5710		 * If offset_lblk is not the starting block of extent, split
5711		 * the extent @offset_lblk
5712		 */
5713		if ((offset_lblk > ee_start_lblk) &&
5714				(offset_lblk < (ee_start_lblk + ee_len))) {
5715			if (ext4_ext_is_unwritten(extent))
5716				split_flag = EXT4_EXT_MARK_UNWRIT1 |
5717					EXT4_EXT_MARK_UNWRIT2;
5718			ret = ext4_split_extent_at(handle, inode, &path,
5719					offset_lblk, split_flag,
5720					EXT4_EX_NOCACHE |
5721					EXT4_GET_BLOCKS_PRE_IO |
5722					EXT4_GET_BLOCKS_METADATA_NOFAIL);
5723		}
5724
5725		ext4_ext_drop_refs(path);
5726		kfree(path);
5727		if (ret < 0) {
5728			up_write(&EXT4_I(inode)->i_data_sem);
5729			goto out_stop;
5730		}
 
 
5731	}
5732
5733	ret = ext4_es_remove_extent(inode, offset_lblk,
5734			EXT_MAX_BLOCKS - offset_lblk);
5735	if (ret) {
5736		up_write(&EXT4_I(inode)->i_data_sem);
5737		goto out_stop;
5738	}
5739
5740	/*
5741	 * if offset_lblk lies in a hole which is at start of file, use
5742	 * ee_start_lblk to shift extents
5743	 */
5744	ret = ext4_ext_shift_extents(inode, handle,
5745		ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5746		len_lblk, SHIFT_RIGHT);
5747
5748	up_write(&EXT4_I(inode)->i_data_sem);
5749	if (IS_SYNC(inode))
5750		ext4_handle_sync(handle);
 
 
5751
5752out_stop:
5753	ext4_journal_stop(handle);
5754out_mmap:
5755	up_write(&EXT4_I(inode)->i_mmap_sem);
5756	ext4_inode_resume_unlocked_dio(inode);
5757out_mutex:
5758	inode_unlock(inode);
5759	return ret;
5760}
5761
5762/**
5763 * ext4_swap_extents - Swap extents between two inodes
5764 *
5765 * @inode1:	First inode
5766 * @inode2:	Second inode
5767 * @lblk1:	Start block for first inode
5768 * @lblk2:	Start block for second inode
5769 * @count:	Number of blocks to swap
5770 * @mark_unwritten: Mark second inode's extents as unwritten after swap
5771 * @erp:	Pointer to save error value
5772 *
5773 * This helper routine does exactly what is promise "swap extents". All other
5774 * stuff such as page-cache locking consistency, bh mapping consistency or
5775 * extent's data copying must be performed by caller.
5776 * Locking:
5777 * 		i_mutex is held for both inodes
5778 * 		i_data_sem is locked for write for both inodes
5779 * Assumptions:
5780 *		All pages from requested range are locked for both inodes
5781 */
5782int
5783ext4_swap_extents(handle_t *handle, struct inode *inode1,
5784		     struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5785		  ext4_lblk_t count, int unwritten, int *erp)
5786{
5787	struct ext4_ext_path *path1 = NULL;
5788	struct ext4_ext_path *path2 = NULL;
5789	int replaced_count = 0;
5790
5791	BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5792	BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5793	BUG_ON(!inode_is_locked(inode1));
5794	BUG_ON(!inode_is_locked(inode2));
5795
5796	*erp = ext4_es_remove_extent(inode1, lblk1, count);
5797	if (unlikely(*erp))
5798		return 0;
5799	*erp = ext4_es_remove_extent(inode2, lblk2, count);
5800	if (unlikely(*erp))
5801		return 0;
5802
5803	while (count) {
5804		struct ext4_extent *ex1, *ex2, tmp_ex;
5805		ext4_lblk_t e1_blk, e2_blk;
5806		int e1_len, e2_len, len;
5807		int split = 0;
5808
5809		path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5810		if (IS_ERR(path1)) {
5811			*erp = PTR_ERR(path1);
5812			path1 = NULL;
5813		finish:
5814			count = 0;
5815			goto repeat;
5816		}
5817		path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5818		if (IS_ERR(path2)) {
5819			*erp = PTR_ERR(path2);
5820			path2 = NULL;
5821			goto finish;
5822		}
5823		ex1 = path1[path1->p_depth].p_ext;
5824		ex2 = path2[path2->p_depth].p_ext;
5825		/* Do we have somthing to swap ? */
5826		if (unlikely(!ex2 || !ex1))
5827			goto finish;
5828
5829		e1_blk = le32_to_cpu(ex1->ee_block);
5830		e2_blk = le32_to_cpu(ex2->ee_block);
5831		e1_len = ext4_ext_get_actual_len(ex1);
5832		e2_len = ext4_ext_get_actual_len(ex2);
5833
5834		/* Hole handling */
5835		if (!in_range(lblk1, e1_blk, e1_len) ||
5836		    !in_range(lblk2, e2_blk, e2_len)) {
5837			ext4_lblk_t next1, next2;
5838
5839			/* if hole after extent, then go to next extent */
5840			next1 = ext4_ext_next_allocated_block(path1);
5841			next2 = ext4_ext_next_allocated_block(path2);
5842			/* If hole before extent, then shift to that extent */
5843			if (e1_blk > lblk1)
5844				next1 = e1_blk;
5845			if (e2_blk > lblk2)
5846				next2 = e1_blk;
5847			/* Do we have something to swap */
5848			if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5849				goto finish;
5850			/* Move to the rightest boundary */
5851			len = next1 - lblk1;
5852			if (len < next2 - lblk2)
5853				len = next2 - lblk2;
5854			if (len > count)
5855				len = count;
5856			lblk1 += len;
5857			lblk2 += len;
5858			count -= len;
5859			goto repeat;
5860		}
5861
5862		/* Prepare left boundary */
5863		if (e1_blk < lblk1) {
5864			split = 1;
5865			*erp = ext4_force_split_extent_at(handle, inode1,
5866						&path1, lblk1, 0);
5867			if (unlikely(*erp))
5868				goto finish;
5869		}
5870		if (e2_blk < lblk2) {
5871			split = 1;
5872			*erp = ext4_force_split_extent_at(handle, inode2,
5873						&path2,  lblk2, 0);
5874			if (unlikely(*erp))
5875				goto finish;
5876		}
5877		/* ext4_split_extent_at() may result in leaf extent split,
5878		 * path must to be revalidated. */
5879		if (split)
5880			goto repeat;
5881
5882		/* Prepare right boundary */
5883		len = count;
5884		if (len > e1_blk + e1_len - lblk1)
5885			len = e1_blk + e1_len - lblk1;
5886		if (len > e2_blk + e2_len - lblk2)
5887			len = e2_blk + e2_len - lblk2;
5888
5889		if (len != e1_len) {
5890			split = 1;
5891			*erp = ext4_force_split_extent_at(handle, inode1,
5892						&path1, lblk1 + len, 0);
5893			if (unlikely(*erp))
5894				goto finish;
5895		}
5896		if (len != e2_len) {
5897			split = 1;
5898			*erp = ext4_force_split_extent_at(handle, inode2,
5899						&path2, lblk2 + len, 0);
5900			if (*erp)
5901				goto finish;
5902		}
5903		/* ext4_split_extent_at() may result in leaf extent split,
5904		 * path must to be revalidated. */
5905		if (split)
5906			goto repeat;
5907
5908		BUG_ON(e2_len != e1_len);
5909		*erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5910		if (unlikely(*erp))
5911			goto finish;
5912		*erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5913		if (unlikely(*erp))
5914			goto finish;
5915
5916		/* Both extents are fully inside boundaries. Swap it now */
5917		tmp_ex = *ex1;
5918		ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5919		ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5920		ex1->ee_len = cpu_to_le16(e2_len);
5921		ex2->ee_len = cpu_to_le16(e1_len);
5922		if (unwritten)
5923			ext4_ext_mark_unwritten(ex2);
5924		if (ext4_ext_is_unwritten(&tmp_ex))
5925			ext4_ext_mark_unwritten(ex1);
5926
5927		ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5928		ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5929		*erp = ext4_ext_dirty(handle, inode2, path2 +
5930				      path2->p_depth);
5931		if (unlikely(*erp))
5932			goto finish;
5933		*erp = ext4_ext_dirty(handle, inode1, path1 +
5934				      path1->p_depth);
5935		/*
5936		 * Looks scarry ah..? second inode already points to new blocks,
5937		 * and it was successfully dirtied. But luckily error may happen
5938		 * only due to journal error, so full transaction will be
5939		 * aborted anyway.
5940		 */
5941		if (unlikely(*erp))
5942			goto finish;
5943		lblk1 += len;
5944		lblk2 += len;
5945		replaced_count += len;
5946		count -= len;
5947
5948	repeat:
5949		ext4_ext_drop_refs(path1);
5950		kfree(path1);
5951		ext4_ext_drop_refs(path2);
5952		kfree(path2);
5953		path1 = path2 = NULL;
5954	}
5955	return replaced_count;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5956}
v6.8
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   4 * Written by Alex Tomas <alex@clusterfs.com>
   5 *
   6 * Architecture independence:
   7 *   Copyright (c) 2005, Bull S.A.
   8 *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
 
 
 
 
 
 
 
 
 
 
 
 
 
   9 */
  10
  11/*
  12 * Extents support for EXT4
  13 *
  14 * TODO:
  15 *   - ext4*_error() should be used in some situations
  16 *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  17 *   - smart tree reduction
  18 */
  19
  20#include <linux/fs.h>
  21#include <linux/time.h>
  22#include <linux/jbd2.h>
  23#include <linux/highuid.h>
  24#include <linux/pagemap.h>
  25#include <linux/quotaops.h>
  26#include <linux/string.h>
  27#include <linux/slab.h>
  28#include <linux/uaccess.h>
  29#include <linux/fiemap.h>
  30#include <linux/iomap.h>
  31#include <linux/sched/mm.h>
  32#include "ext4_jbd2.h"
  33#include "ext4_extents.h"
  34#include "xattr.h"
  35
  36#include <trace/events/ext4.h>
  37
  38/*
  39 * used by extent splitting.
  40 */
  41#define EXT4_EXT_MAY_ZEROOUT	0x1  /* safe to zeroout if split fails \
  42					due to ENOSPC */
  43#define EXT4_EXT_MARK_UNWRIT1	0x2  /* mark first half unwritten */
  44#define EXT4_EXT_MARK_UNWRIT2	0x4  /* mark second half unwritten */
  45
  46#define EXT4_EXT_DATA_VALID1	0x8  /* first half contains valid data */
  47#define EXT4_EXT_DATA_VALID2	0x10 /* second half contains valid data */
  48
  49static __le32 ext4_extent_block_csum(struct inode *inode,
  50				     struct ext4_extent_header *eh)
  51{
  52	struct ext4_inode_info *ei = EXT4_I(inode);
  53	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  54	__u32 csum;
  55
  56	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  57			   EXT4_EXTENT_TAIL_OFFSET(eh));
  58	return cpu_to_le32(csum);
  59}
  60
  61static int ext4_extent_block_csum_verify(struct inode *inode,
  62					 struct ext4_extent_header *eh)
  63{
  64	struct ext4_extent_tail *et;
  65
  66	if (!ext4_has_metadata_csum(inode->i_sb))
  67		return 1;
  68
  69	et = find_ext4_extent_tail(eh);
  70	if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  71		return 0;
  72	return 1;
  73}
  74
  75static void ext4_extent_block_csum_set(struct inode *inode,
  76				       struct ext4_extent_header *eh)
  77{
  78	struct ext4_extent_tail *et;
  79
  80	if (!ext4_has_metadata_csum(inode->i_sb))
  81		return;
  82
  83	et = find_ext4_extent_tail(eh);
  84	et->et_checksum = ext4_extent_block_csum(inode, eh);
  85}
  86
 
 
 
 
 
 
 
  87static int ext4_split_extent_at(handle_t *handle,
  88			     struct inode *inode,
  89			     struct ext4_ext_path **ppath,
  90			     ext4_lblk_t split,
  91			     int split_flag,
  92			     int flags);
  93
  94static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)
  95{
  96	/*
  97	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
  98	 * moment, get_block can be called only for blocks inside i_size since
  99	 * page cache has been already dropped and writes are blocked by
 100	 * i_rwsem. So we can safely drop the i_data_sem here.
 101	 */
 102	BUG_ON(EXT4_JOURNAL(inode) == NULL);
 103	ext4_discard_preallocations(inode);
 104	up_write(&EXT4_I(inode)->i_data_sem);
 105	*dropped = 1;
 106	return 0;
 107}
 108
 109static void ext4_ext_drop_refs(struct ext4_ext_path *path)
 
 
 110{
 111	int depth, i;
 112
 113	if (!path)
 114		return;
 115	depth = path->p_depth;
 116	for (i = 0; i <= depth; i++, path++) {
 117		brelse(path->p_bh);
 118		path->p_bh = NULL;
 119	}
 120}
 
 
 121
 122void ext4_free_ext_path(struct ext4_ext_path *path)
 123{
 124	ext4_ext_drop_refs(path);
 125	kfree(path);
 126}
 127
 128/*
 129 * Make sure 'handle' has at least 'check_cred' credits. If not, restart
 130 * transaction with 'restart_cred' credits. The function drops i_data_sem
 131 * when restarting transaction and gets it after transaction is restarted.
 132 *
 133 * The function returns 0 on success, 1 if transaction had to be restarted,
 134 * and < 0 in case of fatal error.
 135 */
 136int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 137				int check_cred, int restart_cred,
 138				int revoke_cred)
 139{
 140	int ret;
 141	int dropped = 0;
 142
 143	ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
 144		revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
 145	if (dropped)
 146		down_write(&EXT4_I(inode)->i_data_sem);
 147	return ret;
 148}
 149
 150/*
 151 * could return:
 152 *  - EROFS
 153 *  - ENOMEM
 154 */
 155static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 156				struct ext4_ext_path *path)
 157{
 158	int err = 0;
 159
 160	if (path->p_bh) {
 161		/* path points to block */
 162		BUFFER_TRACE(path->p_bh, "get_write_access");
 163		err = ext4_journal_get_write_access(handle, inode->i_sb,
 164						    path->p_bh, EXT4_JTR_NONE);
 165		/*
 166		 * The extent buffer's verified bit will be set again in
 167		 * __ext4_ext_dirty(). We could leave an inconsistent
 168		 * buffer if the extents updating procudure break off du
 169		 * to some error happens, force to check it again.
 170		 */
 171		if (!err)
 172			clear_buffer_verified(path->p_bh);
 173	}
 174	/* path points to leaf/index in inode body */
 175	/* we use in-core data, no need to protect them */
 176	return err;
 177}
 178
 179/*
 180 * could return:
 181 *  - EROFS
 182 *  - ENOMEM
 183 *  - EIO
 184 */
 185static int __ext4_ext_dirty(const char *where, unsigned int line,
 186			    handle_t *handle, struct inode *inode,
 187			    struct ext4_ext_path *path)
 188{
 189	int err;
 190
 191	WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 192	if (path->p_bh) {
 193		ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 194		/* path points to block */
 195		err = __ext4_handle_dirty_metadata(where, line, handle,
 196						   inode, path->p_bh);
 197		/* Extents updating done, re-set verified flag */
 198		if (!err)
 199			set_buffer_verified(path->p_bh);
 200	} else {
 201		/* path points to leaf/index in inode body */
 202		err = ext4_mark_inode_dirty(handle, inode);
 203	}
 204	return err;
 205}
 206
 207#define ext4_ext_dirty(handle, inode, path) \
 208		__ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 209
 210static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 211			      struct ext4_ext_path *path,
 212			      ext4_lblk_t block)
 213{
 214	if (path) {
 215		int depth = path->p_depth;
 216		struct ext4_extent *ex;
 217
 218		/*
 219		 * Try to predict block placement assuming that we are
 220		 * filling in a file which will eventually be
 221		 * non-sparse --- i.e., in the case of libbfd writing
 222		 * an ELF object sections out-of-order but in a way
 223		 * the eventually results in a contiguous object or
 224		 * executable file, or some database extending a table
 225		 * space file.  However, this is actually somewhat
 226		 * non-ideal if we are writing a sparse file such as
 227		 * qemu or KVM writing a raw image file that is going
 228		 * to stay fairly sparse, since it will end up
 229		 * fragmenting the file system's free space.  Maybe we
 230		 * should have some hueristics or some way to allow
 231		 * userspace to pass a hint to file system,
 232		 * especially if the latter case turns out to be
 233		 * common.
 234		 */
 235		ex = path[depth].p_ext;
 236		if (ex) {
 237			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 238			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 239
 240			if (block > ext_block)
 241				return ext_pblk + (block - ext_block);
 242			else
 243				return ext_pblk - (ext_block - block);
 244		}
 245
 246		/* it looks like index is empty;
 247		 * try to find starting block from index itself */
 248		if (path[depth].p_bh)
 249			return path[depth].p_bh->b_blocknr;
 250	}
 251
 252	/* OK. use inode's group */
 253	return ext4_inode_to_goal_block(inode);
 254}
 255
 256/*
 257 * Allocation for a meta data block
 258 */
 259static ext4_fsblk_t
 260ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 261			struct ext4_ext_path *path,
 262			struct ext4_extent *ex, int *err, unsigned int flags)
 263{
 264	ext4_fsblk_t goal, newblock;
 265
 266	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 267	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 268					NULL, err);
 269	return newblock;
 270}
 271
 272static inline int ext4_ext_space_block(struct inode *inode, int check)
 273{
 274	int size;
 275
 276	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 277			/ sizeof(struct ext4_extent);
 278#ifdef AGGRESSIVE_TEST
 279	if (!check && size > 6)
 280		size = 6;
 281#endif
 282	return size;
 283}
 284
 285static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 286{
 287	int size;
 288
 289	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 290			/ sizeof(struct ext4_extent_idx);
 291#ifdef AGGRESSIVE_TEST
 292	if (!check && size > 5)
 293		size = 5;
 294#endif
 295	return size;
 296}
 297
 298static inline int ext4_ext_space_root(struct inode *inode, int check)
 299{
 300	int size;
 301
 302	size = sizeof(EXT4_I(inode)->i_data);
 303	size -= sizeof(struct ext4_extent_header);
 304	size /= sizeof(struct ext4_extent);
 305#ifdef AGGRESSIVE_TEST
 306	if (!check && size > 3)
 307		size = 3;
 308#endif
 309	return size;
 310}
 311
 312static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 313{
 314	int size;
 315
 316	size = sizeof(EXT4_I(inode)->i_data);
 317	size -= sizeof(struct ext4_extent_header);
 318	size /= sizeof(struct ext4_extent_idx);
 319#ifdef AGGRESSIVE_TEST
 320	if (!check && size > 4)
 321		size = 4;
 322#endif
 323	return size;
 324}
 325
 326static inline int
 327ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 328			   struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 329			   int nofail)
 330{
 331	struct ext4_ext_path *path = *ppath;
 332	int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 333	int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 334
 335	if (nofail)
 336		flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 337
 338	return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 339			EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 340			flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 341}
 342
 343static int
 344ext4_ext_max_entries(struct inode *inode, int depth)
 345{
 346	int max;
 347
 348	if (depth == ext_depth(inode)) {
 349		if (depth == 0)
 350			max = ext4_ext_space_root(inode, 1);
 351		else
 352			max = ext4_ext_space_root_idx(inode, 1);
 353	} else {
 354		if (depth == 0)
 355			max = ext4_ext_space_block(inode, 1);
 356		else
 357			max = ext4_ext_space_block_idx(inode, 1);
 358	}
 359
 360	return max;
 361}
 362
 363static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 364{
 365	ext4_fsblk_t block = ext4_ext_pblock(ext);
 366	int len = ext4_ext_get_actual_len(ext);
 367	ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 
 368
 369	/*
 370	 * We allow neither:
 371	 *  - zero length
 372	 *  - overflow/wrap-around
 373	 */
 374	if (lblock + len <= lblock)
 375		return 0;
 376	return ext4_inode_block_valid(inode, block, len);
 377}
 378
 379static int ext4_valid_extent_idx(struct inode *inode,
 380				struct ext4_extent_idx *ext_idx)
 381{
 382	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 383
 384	return ext4_inode_block_valid(inode, block, 1);
 385}
 386
 387static int ext4_valid_extent_entries(struct inode *inode,
 388				     struct ext4_extent_header *eh,
 389				     ext4_lblk_t lblk, ext4_fsblk_t *pblk,
 390				     int depth)
 391{
 392	unsigned short entries;
 393	ext4_lblk_t lblock = 0;
 394	ext4_lblk_t cur = 0;
 395
 396	if (eh->eh_entries == 0)
 397		return 1;
 398
 399	entries = le16_to_cpu(eh->eh_entries);
 400
 401	if (depth == 0) {
 402		/* leaf entries */
 403		struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 404
 405		/*
 406		 * The logical block in the first entry should equal to
 407		 * the number in the index block.
 408		 */
 409		if (depth != ext_depth(inode) &&
 410		    lblk != le32_to_cpu(ext->ee_block))
 411			return 0;
 412		while (entries) {
 413			if (!ext4_valid_extent(inode, ext))
 414				return 0;
 415
 416			/* Check for overlapping extents */
 417			lblock = le32_to_cpu(ext->ee_block);
 418			if (lblock < cur) {
 419				*pblk = ext4_ext_pblock(ext);
 
 
 420				return 0;
 421			}
 422			cur = lblock + ext4_ext_get_actual_len(ext);
 423			ext++;
 424			entries--;
 
 425		}
 426	} else {
 427		struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 428
 429		/*
 430		 * The logical block in the first entry should equal to
 431		 * the number in the parent index block.
 432		 */
 433		if (depth != ext_depth(inode) &&
 434		    lblk != le32_to_cpu(ext_idx->ei_block))
 435			return 0;
 436		while (entries) {
 437			if (!ext4_valid_extent_idx(inode, ext_idx))
 438				return 0;
 439
 440			/* Check for overlapping index extents */
 441			lblock = le32_to_cpu(ext_idx->ei_block);
 442			if (lblock < cur) {
 443				*pblk = ext4_idx_pblock(ext_idx);
 444				return 0;
 445			}
 446			ext_idx++;
 447			entries--;
 448			cur = lblock + 1;
 449		}
 450	}
 451	return 1;
 452}
 453
 454static int __ext4_ext_check(const char *function, unsigned int line,
 455			    struct inode *inode, struct ext4_extent_header *eh,
 456			    int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
 457{
 458	const char *error_msg;
 459	int max = 0, err = -EFSCORRUPTED;
 460
 461	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 462		error_msg = "invalid magic";
 463		goto corrupted;
 464	}
 465	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 466		error_msg = "unexpected eh_depth";
 467		goto corrupted;
 468	}
 469	if (unlikely(eh->eh_max == 0)) {
 470		error_msg = "invalid eh_max";
 471		goto corrupted;
 472	}
 473	max = ext4_ext_max_entries(inode, depth);
 474	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 475		error_msg = "too large eh_max";
 476		goto corrupted;
 477	}
 478	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 479		error_msg = "invalid eh_entries";
 480		goto corrupted;
 481	}
 482	if (unlikely((eh->eh_entries == 0) && (depth > 0))) {
 483		error_msg = "eh_entries is 0 but eh_depth is > 0";
 484		goto corrupted;
 485	}
 486	if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
 487		error_msg = "invalid extent entries";
 488		goto corrupted;
 489	}
 490	if (unlikely(depth > 32)) {
 491		error_msg = "too large eh_depth";
 492		goto corrupted;
 493	}
 494	/* Verify checksum on non-root extent tree nodes */
 495	if (ext_depth(inode) != depth &&
 496	    !ext4_extent_block_csum_verify(inode, eh)) {
 497		error_msg = "extent tree corrupted";
 498		err = -EFSBADCRC;
 499		goto corrupted;
 500	}
 501	return 0;
 502
 503corrupted:
 504	ext4_error_inode_err(inode, function, line, 0, -err,
 505			     "pblk %llu bad header/extent: %s - magic %x, "
 506			     "entries %u, max %u(%u), depth %u(%u)",
 507			     (unsigned long long) pblk, error_msg,
 508			     le16_to_cpu(eh->eh_magic),
 509			     le16_to_cpu(eh->eh_entries),
 510			     le16_to_cpu(eh->eh_max),
 511			     max, le16_to_cpu(eh->eh_depth), depth);
 512	return err;
 513}
 514
 515#define ext4_ext_check(inode, eh, depth, pblk)			\
 516	__ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
 517
 518int ext4_ext_check_inode(struct inode *inode)
 519{
 520	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 521}
 522
 523static void ext4_cache_extents(struct inode *inode,
 524			       struct ext4_extent_header *eh)
 525{
 526	struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 527	ext4_lblk_t prev = 0;
 528	int i;
 529
 530	for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 531		unsigned int status = EXTENT_STATUS_WRITTEN;
 532		ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 533		int len = ext4_ext_get_actual_len(ex);
 534
 535		if (prev && (prev != lblk))
 536			ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
 537					     EXTENT_STATUS_HOLE);
 538
 539		if (ext4_ext_is_unwritten(ex))
 540			status = EXTENT_STATUS_UNWRITTEN;
 541		ext4_es_cache_extent(inode, lblk, len,
 542				     ext4_ext_pblock(ex), status);
 543		prev = lblk + len;
 544	}
 545}
 546
 547static struct buffer_head *
 548__read_extent_tree_block(const char *function, unsigned int line,
 549			 struct inode *inode, struct ext4_extent_idx *idx,
 550			 int depth, int flags)
 551{
 552	struct buffer_head		*bh;
 553	int				err;
 554	gfp_t				gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 555	ext4_fsblk_t			pblk;
 556
 557	if (flags & EXT4_EX_NOFAIL)
 558		gfp_flags |= __GFP_NOFAIL;
 559
 560	pblk = ext4_idx_pblock(idx);
 561	bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 562	if (unlikely(!bh))
 563		return ERR_PTR(-ENOMEM);
 564
 565	if (!bh_uptodate_or_lock(bh)) {
 566		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 567		err = ext4_read_bh(bh, 0, NULL);
 568		if (err < 0)
 569			goto errout;
 570	}
 571	if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 572		return bh;
 573	err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
 574			       depth, pblk, le32_to_cpu(idx->ei_block));
 575	if (err)
 576		goto errout;
 577	set_buffer_verified(bh);
 578	/*
 579	 * If this is a leaf block, cache all of its entries
 580	 */
 581	if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 582		struct ext4_extent_header *eh = ext_block_hdr(bh);
 583		ext4_cache_extents(inode, eh);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 584	}
 585	return bh;
 586errout:
 587	put_bh(bh);
 588	return ERR_PTR(err);
 589
 590}
 591
 592#define read_extent_tree_block(inode, idx, depth, flags)		\
 593	__read_extent_tree_block(__func__, __LINE__, (inode), (idx),	\
 594				 (depth), (flags))
 595
 596/*
 597 * This function is called to cache a file's extent information in the
 598 * extent status tree
 599 */
 600int ext4_ext_precache(struct inode *inode)
 601{
 602	struct ext4_inode_info *ei = EXT4_I(inode);
 603	struct ext4_ext_path *path = NULL;
 604	struct buffer_head *bh;
 605	int i = 0, depth, ret = 0;
 606
 607	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 608		return 0;	/* not an extent-mapped inode */
 609
 610	down_read(&ei->i_data_sem);
 611	depth = ext_depth(inode);
 612
 613	/* Don't cache anything if there are no external extent blocks */
 614	if (!depth) {
 615		up_read(&ei->i_data_sem);
 616		return ret;
 617	}
 618
 619	path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 620		       GFP_NOFS);
 621	if (path == NULL) {
 622		up_read(&ei->i_data_sem);
 623		return -ENOMEM;
 624	}
 625
 
 
 
 626	path[0].p_hdr = ext_inode_hdr(inode);
 627	ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 628	if (ret)
 629		goto out;
 630	path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 631	while (i >= 0) {
 632		/*
 633		 * If this is a leaf block or we've reached the end of
 634		 * the index block, go up
 635		 */
 636		if ((i == depth) ||
 637		    path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 638			brelse(path[i].p_bh);
 639			path[i].p_bh = NULL;
 640			i--;
 641			continue;
 642		}
 643		bh = read_extent_tree_block(inode, path[i].p_idx++,
 
 644					    depth - i - 1,
 645					    EXT4_EX_FORCE_CACHE);
 646		if (IS_ERR(bh)) {
 647			ret = PTR_ERR(bh);
 648			break;
 649		}
 650		i++;
 651		path[i].p_bh = bh;
 652		path[i].p_hdr = ext_block_hdr(bh);
 653		path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 654	}
 655	ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 656out:
 657	up_read(&ei->i_data_sem);
 658	ext4_free_ext_path(path);
 
 659	return ret;
 660}
 661
 662#ifdef EXT_DEBUG
 663static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 664{
 665	int k, l = path->p_depth;
 666
 667	ext_debug(inode, "path:");
 668	for (k = 0; k <= l; k++, path++) {
 669		if (path->p_idx) {
 670			ext_debug(inode, "  %d->%llu",
 671				  le32_to_cpu(path->p_idx->ei_block),
 672				  ext4_idx_pblock(path->p_idx));
 673		} else if (path->p_ext) {
 674			ext_debug(inode, "  %d:[%d]%d:%llu ",
 675				  le32_to_cpu(path->p_ext->ee_block),
 676				  ext4_ext_is_unwritten(path->p_ext),
 677				  ext4_ext_get_actual_len(path->p_ext),
 678				  ext4_ext_pblock(path->p_ext));
 679		} else
 680			ext_debug(inode, "  []");
 681	}
 682	ext_debug(inode, "\n");
 683}
 684
 685static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 686{
 687	int depth = ext_depth(inode);
 688	struct ext4_extent_header *eh;
 689	struct ext4_extent *ex;
 690	int i;
 691
 692	if (!path)
 693		return;
 694
 695	eh = path[depth].p_hdr;
 696	ex = EXT_FIRST_EXTENT(eh);
 697
 698	ext_debug(inode, "Displaying leaf extents\n");
 699
 700	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 701		ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 702			  ext4_ext_is_unwritten(ex),
 703			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 704	}
 705	ext_debug(inode, "\n");
 706}
 707
 708static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 709			ext4_fsblk_t newblock, int level)
 710{
 711	int depth = ext_depth(inode);
 712	struct ext4_extent *ex;
 713
 714	if (depth != level) {
 715		struct ext4_extent_idx *idx;
 716		idx = path[level].p_idx;
 717		while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 718			ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 719				  level, le32_to_cpu(idx->ei_block),
 720				  ext4_idx_pblock(idx), newblock);
 
 721			idx++;
 722		}
 723
 724		return;
 725	}
 726
 727	ex = path[depth].p_ext;
 728	while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 729		ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 730				le32_to_cpu(ex->ee_block),
 731				ext4_ext_pblock(ex),
 732				ext4_ext_is_unwritten(ex),
 733				ext4_ext_get_actual_len(ex),
 734				newblock);
 735		ex++;
 736	}
 737}
 738
 739#else
 740#define ext4_ext_show_path(inode, path)
 741#define ext4_ext_show_leaf(inode, path)
 742#define ext4_ext_show_move(inode, path, newblock, level)
 743#endif
 744
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 745/*
 746 * ext4_ext_binsearch_idx:
 747 * binary search for the closest index of the given block
 748 * the header must be checked before calling this
 749 */
 750static void
 751ext4_ext_binsearch_idx(struct inode *inode,
 752			struct ext4_ext_path *path, ext4_lblk_t block)
 753{
 754	struct ext4_extent_header *eh = path->p_hdr;
 755	struct ext4_extent_idx *r, *l, *m;
 756
 757
 758	ext_debug(inode, "binsearch for %u(idx):  ", block);
 759
 760	l = EXT_FIRST_INDEX(eh) + 1;
 761	r = EXT_LAST_INDEX(eh);
 762	while (l <= r) {
 763		m = l + (r - l) / 2;
 764		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 765			  le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 766			  r, le32_to_cpu(r->ei_block));
 767
 768		if (block < le32_to_cpu(m->ei_block))
 769			r = m - 1;
 770		else
 771			l = m + 1;
 
 
 
 772	}
 773
 774	path->p_idx = l - 1;
 775	ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 776		  ext4_idx_pblock(path->p_idx));
 777
 778#ifdef CHECK_BINSEARCH
 779	{
 780		struct ext4_extent_idx *chix, *ix;
 781		int k;
 782
 783		chix = ix = EXT_FIRST_INDEX(eh);
 784		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 785			if (k != 0 && le32_to_cpu(ix->ei_block) <=
 786			    le32_to_cpu(ix[-1].ei_block)) {
 787				printk(KERN_DEBUG "k=%d, ix=0x%p, "
 788				       "first=0x%p\n", k,
 789				       ix, EXT_FIRST_INDEX(eh));
 790				printk(KERN_DEBUG "%u <= %u\n",
 791				       le32_to_cpu(ix->ei_block),
 792				       le32_to_cpu(ix[-1].ei_block));
 793			}
 794			BUG_ON(k && le32_to_cpu(ix->ei_block)
 795					   <= le32_to_cpu(ix[-1].ei_block));
 796			if (block < le32_to_cpu(ix->ei_block))
 797				break;
 798			chix = ix;
 799		}
 800		BUG_ON(chix != path->p_idx);
 801	}
 802#endif
 803
 804}
 805
 806/*
 807 * ext4_ext_binsearch:
 808 * binary search for closest extent of the given block
 809 * the header must be checked before calling this
 810 */
 811static void
 812ext4_ext_binsearch(struct inode *inode,
 813		struct ext4_ext_path *path, ext4_lblk_t block)
 814{
 815	struct ext4_extent_header *eh = path->p_hdr;
 816	struct ext4_extent *r, *l, *m;
 817
 818	if (eh->eh_entries == 0) {
 819		/*
 820		 * this leaf is empty:
 821		 * we get such a leaf in split/add case
 822		 */
 823		return;
 824	}
 825
 826	ext_debug(inode, "binsearch for %u:  ", block);
 827
 828	l = EXT_FIRST_EXTENT(eh) + 1;
 829	r = EXT_LAST_EXTENT(eh);
 830
 831	while (l <= r) {
 832		m = l + (r - l) / 2;
 833		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 834			  le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 835			  r, le32_to_cpu(r->ee_block));
 836
 837		if (block < le32_to_cpu(m->ee_block))
 838			r = m - 1;
 839		else
 840			l = m + 1;
 
 
 
 841	}
 842
 843	path->p_ext = l - 1;
 844	ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 845			le32_to_cpu(path->p_ext->ee_block),
 846			ext4_ext_pblock(path->p_ext),
 847			ext4_ext_is_unwritten(path->p_ext),
 848			ext4_ext_get_actual_len(path->p_ext));
 849
 850#ifdef CHECK_BINSEARCH
 851	{
 852		struct ext4_extent *chex, *ex;
 853		int k;
 854
 855		chex = ex = EXT_FIRST_EXTENT(eh);
 856		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 857			BUG_ON(k && le32_to_cpu(ex->ee_block)
 858					  <= le32_to_cpu(ex[-1].ee_block));
 859			if (block < le32_to_cpu(ex->ee_block))
 860				break;
 861			chex = ex;
 862		}
 863		BUG_ON(chex != path->p_ext);
 864	}
 865#endif
 866
 867}
 868
 869void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 870{
 871	struct ext4_extent_header *eh;
 872
 873	eh = ext_inode_hdr(inode);
 874	eh->eh_depth = 0;
 875	eh->eh_entries = 0;
 876	eh->eh_magic = EXT4_EXT_MAGIC;
 877	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 878	eh->eh_generation = 0;
 879	ext4_mark_inode_dirty(handle, inode);
 
 880}
 881
 882struct ext4_ext_path *
 883ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 884		 struct ext4_ext_path **orig_path, int flags)
 885{
 886	struct ext4_extent_header *eh;
 887	struct buffer_head *bh;
 888	struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 889	short int depth, i, ppos = 0;
 890	int ret;
 891	gfp_t gfp_flags = GFP_NOFS;
 892
 893	if (flags & EXT4_EX_NOFAIL)
 894		gfp_flags |= __GFP_NOFAIL;
 895
 896	eh = ext_inode_hdr(inode);
 897	depth = ext_depth(inode);
 898	if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 899		EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 900				 depth);
 901		ret = -EFSCORRUPTED;
 902		goto err;
 903	}
 904
 905	if (path) {
 906		ext4_ext_drop_refs(path);
 907		if (depth > path[0].p_maxdepth) {
 908			kfree(path);
 909			*orig_path = path = NULL;
 910		}
 911	}
 912	if (!path) {
 913		/* account possible depth increase */
 914		path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 915				gfp_flags);
 916		if (unlikely(!path))
 917			return ERR_PTR(-ENOMEM);
 918		path[0].p_maxdepth = depth + 1;
 919	}
 920	path[0].p_hdr = eh;
 921	path[0].p_bh = NULL;
 922
 923	i = depth;
 924	if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 925		ext4_cache_extents(inode, eh);
 926	/* walk through the tree */
 927	while (i) {
 928		ext_debug(inode, "depth %d: num %d, max %d\n",
 929			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 930
 931		ext4_ext_binsearch_idx(inode, path + ppos, block);
 932		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 933		path[ppos].p_depth = i;
 934		path[ppos].p_ext = NULL;
 935
 936		bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
 
 937		if (IS_ERR(bh)) {
 938			ret = PTR_ERR(bh);
 939			goto err;
 940		}
 941
 942		eh = ext_block_hdr(bh);
 943		ppos++;
 
 
 
 
 
 
 
 944		path[ppos].p_bh = bh;
 945		path[ppos].p_hdr = eh;
 946	}
 947
 948	path[ppos].p_depth = i;
 949	path[ppos].p_ext = NULL;
 950	path[ppos].p_idx = NULL;
 951
 952	/* find extent */
 953	ext4_ext_binsearch(inode, path + ppos, block);
 954	/* if not an empty leaf */
 955	if (path[ppos].p_ext)
 956		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 957
 958	ext4_ext_show_path(inode, path);
 959
 960	return path;
 961
 962err:
 963	ext4_free_ext_path(path);
 
 964	if (orig_path)
 965		*orig_path = NULL;
 966	return ERR_PTR(ret);
 967}
 968
 969/*
 970 * ext4_ext_insert_index:
 971 * insert new index [@logical;@ptr] into the block at @curp;
 972 * check where to insert: before @curp or after @curp
 973 */
 974static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 975				 struct ext4_ext_path *curp,
 976				 int logical, ext4_fsblk_t ptr)
 977{
 978	struct ext4_extent_idx *ix;
 979	int len, err;
 980
 981	err = ext4_ext_get_access(handle, inode, curp);
 982	if (err)
 983		return err;
 984
 985	if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 986		EXT4_ERROR_INODE(inode,
 987				 "logical %d == ei_block %d!",
 988				 logical, le32_to_cpu(curp->p_idx->ei_block));
 989		return -EFSCORRUPTED;
 990	}
 991
 992	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 993			     >= le16_to_cpu(curp->p_hdr->eh_max))) {
 994		EXT4_ERROR_INODE(inode,
 995				 "eh_entries %d >= eh_max %d!",
 996				 le16_to_cpu(curp->p_hdr->eh_entries),
 997				 le16_to_cpu(curp->p_hdr->eh_max));
 998		return -EFSCORRUPTED;
 999	}
1000
1001	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
1002		/* insert after */
1003		ext_debug(inode, "insert new index %d after: %llu\n",
1004			  logical, ptr);
1005		ix = curp->p_idx + 1;
1006	} else {
1007		/* insert before */
1008		ext_debug(inode, "insert new index %d before: %llu\n",
1009			  logical, ptr);
1010		ix = curp->p_idx;
1011	}
1012
1013	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
1014		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1015		return -EFSCORRUPTED;
1016	}
1017
1018	len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
1019	BUG_ON(len < 0);
1020	if (len > 0) {
1021		ext_debug(inode, "insert new index %d: "
1022				"move %d indices from 0x%p to 0x%p\n",
1023				logical, len, ix, ix + 1);
1024		memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
1025	}
1026
 
 
 
 
 
1027	ix->ei_block = cpu_to_le32(logical);
1028	ext4_idx_store_pblock(ix, ptr);
1029	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1030
1031	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1032		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1033		return -EFSCORRUPTED;
1034	}
1035
1036	err = ext4_ext_dirty(handle, inode, curp);
1037	ext4_std_error(inode->i_sb, err);
1038
1039	return err;
1040}
1041
1042/*
1043 * ext4_ext_split:
1044 * inserts new subtree into the path, using free index entry
1045 * at depth @at:
1046 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1047 * - makes decision where to split
1048 * - moves remaining extents and index entries (right to the split point)
1049 *   into the newly allocated blocks
1050 * - initializes subtree
1051 */
1052static int ext4_ext_split(handle_t *handle, struct inode *inode,
1053			  unsigned int flags,
1054			  struct ext4_ext_path *path,
1055			  struct ext4_extent *newext, int at)
1056{
1057	struct buffer_head *bh = NULL;
1058	int depth = ext_depth(inode);
1059	struct ext4_extent_header *neh;
1060	struct ext4_extent_idx *fidx;
1061	int i = at, k, m, a;
1062	ext4_fsblk_t newblock, oldblock;
1063	__le32 border;
1064	ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1065	gfp_t gfp_flags = GFP_NOFS;
1066	int err = 0;
1067	size_t ext_size = 0;
1068
1069	if (flags & EXT4_EX_NOFAIL)
1070		gfp_flags |= __GFP_NOFAIL;
1071
1072	/* make decision: where to split? */
1073	/* FIXME: now decision is simplest: at current extent */
1074
1075	/* if current leaf will be split, then we should use
1076	 * border from split point */
1077	if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1078		EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1079		return -EFSCORRUPTED;
1080	}
1081	if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1082		border = path[depth].p_ext[1].ee_block;
1083		ext_debug(inode, "leaf will be split."
1084				" next leaf starts at %d\n",
1085				  le32_to_cpu(border));
1086	} else {
1087		border = newext->ee_block;
1088		ext_debug(inode, "leaf will be added."
1089				" next leaf starts at %d\n",
1090				le32_to_cpu(border));
1091	}
1092
1093	/*
1094	 * If error occurs, then we break processing
1095	 * and mark filesystem read-only. index won't
1096	 * be inserted and tree will be in consistent
1097	 * state. Next mount will repair buffers too.
1098	 */
1099
1100	/*
1101	 * Get array to track all allocated blocks.
1102	 * We need this to handle errors and free blocks
1103	 * upon them.
1104	 */
1105	ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);
1106	if (!ablocks)
1107		return -ENOMEM;
1108
1109	/* allocate all needed blocks */
1110	ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);
1111	for (a = 0; a < depth - at; a++) {
1112		newblock = ext4_ext_new_meta_block(handle, inode, path,
1113						   newext, &err, flags);
1114		if (newblock == 0)
1115			goto cleanup;
1116		ablocks[a] = newblock;
1117	}
1118
1119	/* initialize new leaf */
1120	newblock = ablocks[--a];
1121	if (unlikely(newblock == 0)) {
1122		EXT4_ERROR_INODE(inode, "newblock == 0!");
1123		err = -EFSCORRUPTED;
1124		goto cleanup;
1125	}
1126	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1127	if (unlikely(!bh)) {
1128		err = -ENOMEM;
1129		goto cleanup;
1130	}
1131	lock_buffer(bh);
1132
1133	err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1134					     EXT4_JTR_NONE);
1135	if (err)
1136		goto cleanup;
1137
1138	neh = ext_block_hdr(bh);
1139	neh->eh_entries = 0;
1140	neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1141	neh->eh_magic = EXT4_EXT_MAGIC;
1142	neh->eh_depth = 0;
1143	neh->eh_generation = 0;
1144
1145	/* move remainder of path[depth] to the new leaf */
1146	if (unlikely(path[depth].p_hdr->eh_entries !=
1147		     path[depth].p_hdr->eh_max)) {
1148		EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1149				 path[depth].p_hdr->eh_entries,
1150				 path[depth].p_hdr->eh_max);
1151		err = -EFSCORRUPTED;
1152		goto cleanup;
1153	}
1154	/* start copy from next extent */
1155	m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1156	ext4_ext_show_move(inode, path, newblock, depth);
1157	if (m) {
1158		struct ext4_extent *ex;
1159		ex = EXT_FIRST_EXTENT(neh);
1160		memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1161		le16_add_cpu(&neh->eh_entries, m);
1162	}
1163
1164	/* zero out unused area in the extent block */
1165	ext_size = sizeof(struct ext4_extent_header) +
1166		sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1167	memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1168	ext4_extent_block_csum_set(inode, neh);
1169	set_buffer_uptodate(bh);
1170	unlock_buffer(bh);
1171
1172	err = ext4_handle_dirty_metadata(handle, inode, bh);
1173	if (err)
1174		goto cleanup;
1175	brelse(bh);
1176	bh = NULL;
1177
1178	/* correct old leaf */
1179	if (m) {
1180		err = ext4_ext_get_access(handle, inode, path + depth);
1181		if (err)
1182			goto cleanup;
1183		le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1184		err = ext4_ext_dirty(handle, inode, path + depth);
1185		if (err)
1186			goto cleanup;
1187
1188	}
1189
1190	/* create intermediate indexes */
1191	k = depth - at - 1;
1192	if (unlikely(k < 0)) {
1193		EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1194		err = -EFSCORRUPTED;
1195		goto cleanup;
1196	}
1197	if (k)
1198		ext_debug(inode, "create %d intermediate indices\n", k);
1199	/* insert new index into current index block */
1200	/* current depth stored in i var */
1201	i = depth - 1;
1202	while (k--) {
1203		oldblock = newblock;
1204		newblock = ablocks[--a];
1205		bh = sb_getblk(inode->i_sb, newblock);
1206		if (unlikely(!bh)) {
1207			err = -ENOMEM;
1208			goto cleanup;
1209		}
1210		lock_buffer(bh);
1211
1212		err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1213						     EXT4_JTR_NONE);
1214		if (err)
1215			goto cleanup;
1216
1217		neh = ext_block_hdr(bh);
1218		neh->eh_entries = cpu_to_le16(1);
1219		neh->eh_magic = EXT4_EXT_MAGIC;
1220		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1221		neh->eh_depth = cpu_to_le16(depth - i);
1222		neh->eh_generation = 0;
1223		fidx = EXT_FIRST_INDEX(neh);
1224		fidx->ei_block = border;
1225		ext4_idx_store_pblock(fidx, oldblock);
1226
1227		ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",
1228				i, newblock, le32_to_cpu(border), oldblock);
1229
1230		/* move remainder of path[i] to the new index block */
1231		if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1232					EXT_LAST_INDEX(path[i].p_hdr))) {
1233			EXT4_ERROR_INODE(inode,
1234					 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1235					 le32_to_cpu(path[i].p_ext->ee_block));
1236			err = -EFSCORRUPTED;
1237			goto cleanup;
1238		}
1239		/* start copy indexes */
1240		m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1241		ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
1242				EXT_MAX_INDEX(path[i].p_hdr));
1243		ext4_ext_show_move(inode, path, newblock, i);
1244		if (m) {
1245			memmove(++fidx, path[i].p_idx,
1246				sizeof(struct ext4_extent_idx) * m);
1247			le16_add_cpu(&neh->eh_entries, m);
1248		}
1249		/* zero out unused area in the extent block */
1250		ext_size = sizeof(struct ext4_extent_header) +
1251		   (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1252		memset(bh->b_data + ext_size, 0,
1253			inode->i_sb->s_blocksize - ext_size);
1254		ext4_extent_block_csum_set(inode, neh);
1255		set_buffer_uptodate(bh);
1256		unlock_buffer(bh);
1257
1258		err = ext4_handle_dirty_metadata(handle, inode, bh);
1259		if (err)
1260			goto cleanup;
1261		brelse(bh);
1262		bh = NULL;
1263
1264		/* correct old index */
1265		if (m) {
1266			err = ext4_ext_get_access(handle, inode, path + i);
1267			if (err)
1268				goto cleanup;
1269			le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1270			err = ext4_ext_dirty(handle, inode, path + i);
1271			if (err)
1272				goto cleanup;
1273		}
1274
1275		i--;
1276	}
1277
1278	/* insert new index */
1279	err = ext4_ext_insert_index(handle, inode, path + at,
1280				    le32_to_cpu(border), newblock);
1281
1282cleanup:
1283	if (bh) {
1284		if (buffer_locked(bh))
1285			unlock_buffer(bh);
1286		brelse(bh);
1287	}
1288
1289	if (err) {
1290		/* free all allocated blocks in error case */
1291		for (i = 0; i < depth; i++) {
1292			if (!ablocks[i])
1293				continue;
1294			ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1295					 EXT4_FREE_BLOCKS_METADATA);
1296		}
1297	}
1298	kfree(ablocks);
1299
1300	return err;
1301}
1302
1303/*
1304 * ext4_ext_grow_indepth:
1305 * implements tree growing procedure:
1306 * - allocates new block
1307 * - moves top-level data (index block or leaf) into the new block
1308 * - initializes new top-level, creating index that points to the
1309 *   just created block
1310 */
1311static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1312				 unsigned int flags)
1313{
1314	struct ext4_extent_header *neh;
1315	struct buffer_head *bh;
1316	ext4_fsblk_t newblock, goal = 0;
1317	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1318	int err = 0;
1319	size_t ext_size = 0;
1320
1321	/* Try to prepend new index to old one */
1322	if (ext_depth(inode))
1323		goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1324	if (goal > le32_to_cpu(es->s_first_data_block)) {
1325		flags |= EXT4_MB_HINT_TRY_GOAL;
1326		goal--;
1327	} else
1328		goal = ext4_inode_to_goal_block(inode);
1329	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1330					NULL, &err);
1331	if (newblock == 0)
1332		return err;
1333
1334	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1335	if (unlikely(!bh))
1336		return -ENOMEM;
1337	lock_buffer(bh);
1338
1339	err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1340					     EXT4_JTR_NONE);
1341	if (err) {
1342		unlock_buffer(bh);
1343		goto out;
1344	}
1345
1346	ext_size = sizeof(EXT4_I(inode)->i_data);
1347	/* move top-level index/leaf into new block */
1348	memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1349	/* zero out unused area in the extent block */
1350	memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1351
1352	/* set size of new block */
1353	neh = ext_block_hdr(bh);
1354	/* old root could have indexes or leaves
1355	 * so calculate e_max right way */
1356	if (ext_depth(inode))
1357		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1358	else
1359		neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1360	neh->eh_magic = EXT4_EXT_MAGIC;
1361	ext4_extent_block_csum_set(inode, neh);
1362	set_buffer_uptodate(bh);
1363	set_buffer_verified(bh);
1364	unlock_buffer(bh);
1365
1366	err = ext4_handle_dirty_metadata(handle, inode, bh);
1367	if (err)
1368		goto out;
1369
1370	/* Update top-level index: num,max,pointer */
1371	neh = ext_inode_hdr(inode);
1372	neh->eh_entries = cpu_to_le16(1);
1373	ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1374	if (neh->eh_depth == 0) {
1375		/* Root extent block becomes index block */
1376		neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1377		EXT_FIRST_INDEX(neh)->ei_block =
1378			EXT_FIRST_EXTENT(neh)->ee_block;
1379	}
1380	ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",
1381		  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1382		  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1383		  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1384
1385	le16_add_cpu(&neh->eh_depth, 1);
1386	err = ext4_mark_inode_dirty(handle, inode);
1387out:
1388	brelse(bh);
1389
1390	return err;
1391}
1392
1393/*
1394 * ext4_ext_create_new_leaf:
1395 * finds empty index and adds new leaf.
1396 * if no free index is found, then it requests in-depth growing.
1397 */
1398static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1399				    unsigned int mb_flags,
1400				    unsigned int gb_flags,
1401				    struct ext4_ext_path **ppath,
1402				    struct ext4_extent *newext)
1403{
1404	struct ext4_ext_path *path = *ppath;
1405	struct ext4_ext_path *curp;
1406	int depth, i, err = 0;
1407
1408repeat:
1409	i = depth = ext_depth(inode);
1410
1411	/* walk up to the tree and look for free index entry */
1412	curp = path + depth;
1413	while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1414		i--;
1415		curp--;
1416	}
1417
1418	/* we use already allocated block for index block,
1419	 * so subsequent data blocks should be contiguous */
1420	if (EXT_HAS_FREE_INDEX(curp)) {
1421		/* if we found index with free entry, then use that
1422		 * entry: create all needed subtree and add new leaf */
1423		err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1424		if (err)
1425			goto out;
1426
1427		/* refill path */
1428		path = ext4_find_extent(inode,
1429				    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1430				    ppath, gb_flags);
1431		if (IS_ERR(path))
1432			err = PTR_ERR(path);
1433	} else {
1434		/* tree is full, time to grow in depth */
1435		err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1436		if (err)
1437			goto out;
1438
1439		/* refill path */
1440		path = ext4_find_extent(inode,
1441				   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1442				    ppath, gb_flags);
1443		if (IS_ERR(path)) {
1444			err = PTR_ERR(path);
1445			goto out;
1446		}
1447
1448		/*
1449		 * only first (depth 0 -> 1) produces free space;
1450		 * in all other cases we have to split the grown tree
1451		 */
1452		depth = ext_depth(inode);
1453		if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1454			/* now we need to split */
1455			goto repeat;
1456		}
1457	}
1458
1459out:
1460	return err;
1461}
1462
1463/*
1464 * search the closest allocated block to the left for *logical
1465 * and returns it at @logical + it's physical address at @phys
1466 * if *logical is the smallest allocated block, the function
1467 * returns 0 at @phys
1468 * return value contains 0 (success) or error code
1469 */
1470static int ext4_ext_search_left(struct inode *inode,
1471				struct ext4_ext_path *path,
1472				ext4_lblk_t *logical, ext4_fsblk_t *phys)
1473{
1474	struct ext4_extent_idx *ix;
1475	struct ext4_extent *ex;
1476	int depth, ee_len;
1477
1478	if (unlikely(path == NULL)) {
1479		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1480		return -EFSCORRUPTED;
1481	}
1482	depth = path->p_depth;
1483	*phys = 0;
1484
1485	if (depth == 0 && path->p_ext == NULL)
1486		return 0;
1487
1488	/* usually extent in the path covers blocks smaller
1489	 * then *logical, but it can be that extent is the
1490	 * first one in the file */
1491
1492	ex = path[depth].p_ext;
1493	ee_len = ext4_ext_get_actual_len(ex);
1494	if (*logical < le32_to_cpu(ex->ee_block)) {
1495		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1496			EXT4_ERROR_INODE(inode,
1497					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1498					 *logical, le32_to_cpu(ex->ee_block));
1499			return -EFSCORRUPTED;
1500		}
1501		while (--depth >= 0) {
1502			ix = path[depth].p_idx;
1503			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1504				EXT4_ERROR_INODE(inode,
1505				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1506				  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1507				  le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),
 
1508				  depth);
1509				return -EFSCORRUPTED;
1510			}
1511		}
1512		return 0;
1513	}
1514
1515	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1516		EXT4_ERROR_INODE(inode,
1517				 "logical %d < ee_block %d + ee_len %d!",
1518				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1519		return -EFSCORRUPTED;
1520	}
1521
1522	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1523	*phys = ext4_ext_pblock(ex) + ee_len - 1;
1524	return 0;
1525}
1526
1527/*
1528 * Search the closest allocated block to the right for *logical
1529 * and returns it at @logical + it's physical address at @phys.
1530 * If not exists, return 0 and @phys is set to 0. We will return
1531 * 1 which means we found an allocated block and ret_ex is valid.
1532 * Or return a (< 0) error code.
1533 */
1534static int ext4_ext_search_right(struct inode *inode,
1535				 struct ext4_ext_path *path,
1536				 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1537				 struct ext4_extent *ret_ex)
1538{
1539	struct buffer_head *bh = NULL;
1540	struct ext4_extent_header *eh;
1541	struct ext4_extent_idx *ix;
1542	struct ext4_extent *ex;
 
1543	int depth;	/* Note, NOT eh_depth; depth from top of tree */
1544	int ee_len;
1545
1546	if (unlikely(path == NULL)) {
1547		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1548		return -EFSCORRUPTED;
1549	}
1550	depth = path->p_depth;
1551	*phys = 0;
1552
1553	if (depth == 0 && path->p_ext == NULL)
1554		return 0;
1555
1556	/* usually extent in the path covers blocks smaller
1557	 * then *logical, but it can be that extent is the
1558	 * first one in the file */
1559
1560	ex = path[depth].p_ext;
1561	ee_len = ext4_ext_get_actual_len(ex);
1562	if (*logical < le32_to_cpu(ex->ee_block)) {
1563		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1564			EXT4_ERROR_INODE(inode,
1565					 "first_extent(path[%d].p_hdr) != ex",
1566					 depth);
1567			return -EFSCORRUPTED;
1568		}
1569		while (--depth >= 0) {
1570			ix = path[depth].p_idx;
1571			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1572				EXT4_ERROR_INODE(inode,
1573						 "ix != EXT_FIRST_INDEX *logical %d!",
1574						 *logical);
1575				return -EFSCORRUPTED;
1576			}
1577		}
1578		goto found_extent;
1579	}
1580
1581	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1582		EXT4_ERROR_INODE(inode,
1583				 "logical %d < ee_block %d + ee_len %d!",
1584				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1585		return -EFSCORRUPTED;
1586	}
1587
1588	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1589		/* next allocated block in this leaf */
1590		ex++;
1591		goto found_extent;
1592	}
1593
1594	/* go up and search for index to the right */
1595	while (--depth >= 0) {
1596		ix = path[depth].p_idx;
1597		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1598			goto got_index;
1599	}
1600
1601	/* we've gone up to the root and found no index to the right */
1602	return 0;
1603
1604got_index:
1605	/* we've found index to the right, let's
1606	 * follow it and find the closest allocated
1607	 * block to the right */
1608	ix++;
 
1609	while (++depth < path->p_depth) {
1610		/* subtract from p_depth to get proper eh_depth */
1611		bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
 
1612		if (IS_ERR(bh))
1613			return PTR_ERR(bh);
1614		eh = ext_block_hdr(bh);
1615		ix = EXT_FIRST_INDEX(eh);
 
1616		put_bh(bh);
1617	}
1618
1619	bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1620	if (IS_ERR(bh))
1621		return PTR_ERR(bh);
1622	eh = ext_block_hdr(bh);
1623	ex = EXT_FIRST_EXTENT(eh);
1624found_extent:
1625	*logical = le32_to_cpu(ex->ee_block);
1626	*phys = ext4_ext_pblock(ex);
1627	if (ret_ex)
1628		*ret_ex = *ex;
1629	if (bh)
1630		put_bh(bh);
1631	return 1;
1632}
1633
1634/*
1635 * ext4_ext_next_allocated_block:
1636 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1637 * NOTE: it considers block number from index entry as
1638 * allocated block. Thus, index entries have to be consistent
1639 * with leaves.
1640 */
1641ext4_lblk_t
1642ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1643{
1644	int depth;
1645
1646	BUG_ON(path == NULL);
1647	depth = path->p_depth;
1648
1649	if (depth == 0 && path->p_ext == NULL)
1650		return EXT_MAX_BLOCKS;
1651
1652	while (depth >= 0) {
1653		struct ext4_ext_path *p = &path[depth];
1654
1655		if (depth == path->p_depth) {
1656			/* leaf */
1657			if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1658				return le32_to_cpu(p->p_ext[1].ee_block);
 
 
1659		} else {
1660			/* index */
1661			if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1662				return le32_to_cpu(p->p_idx[1].ei_block);
 
1663		}
1664		depth--;
1665	}
1666
1667	return EXT_MAX_BLOCKS;
1668}
1669
1670/*
1671 * ext4_ext_next_leaf_block:
1672 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1673 */
1674static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1675{
1676	int depth;
1677
1678	BUG_ON(path == NULL);
1679	depth = path->p_depth;
1680
1681	/* zero-tree has no leaf blocks at all */
1682	if (depth == 0)
1683		return EXT_MAX_BLOCKS;
1684
1685	/* go to index block */
1686	depth--;
1687
1688	while (depth >= 0) {
1689		if (path[depth].p_idx !=
1690				EXT_LAST_INDEX(path[depth].p_hdr))
1691			return (ext4_lblk_t)
1692				le32_to_cpu(path[depth].p_idx[1].ei_block);
1693		depth--;
1694	}
1695
1696	return EXT_MAX_BLOCKS;
1697}
1698
1699/*
1700 * ext4_ext_correct_indexes:
1701 * if leaf gets modified and modified extent is first in the leaf,
1702 * then we have to correct all indexes above.
1703 * TODO: do we need to correct tree in all cases?
1704 */
1705static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1706				struct ext4_ext_path *path)
1707{
1708	struct ext4_extent_header *eh;
1709	int depth = ext_depth(inode);
1710	struct ext4_extent *ex;
1711	__le32 border;
1712	int k, err = 0;
1713
1714	eh = path[depth].p_hdr;
1715	ex = path[depth].p_ext;
1716
1717	if (unlikely(ex == NULL || eh == NULL)) {
1718		EXT4_ERROR_INODE(inode,
1719				 "ex %p == NULL or eh %p == NULL", ex, eh);
1720		return -EFSCORRUPTED;
1721	}
1722
1723	if (depth == 0) {
1724		/* there is no tree at all */
1725		return 0;
1726	}
1727
1728	if (ex != EXT_FIRST_EXTENT(eh)) {
1729		/* we correct tree if first leaf got modified only */
1730		return 0;
1731	}
1732
1733	/*
1734	 * TODO: we need correction if border is smaller than current one
1735	 */
1736	k = depth - 1;
1737	border = path[depth].p_ext->ee_block;
1738	err = ext4_ext_get_access(handle, inode, path + k);
1739	if (err)
1740		return err;
1741	path[k].p_idx->ei_block = border;
1742	err = ext4_ext_dirty(handle, inode, path + k);
1743	if (err)
1744		return err;
1745
1746	while (k--) {
1747		/* change all left-side indexes */
1748		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1749			break;
1750		err = ext4_ext_get_access(handle, inode, path + k);
1751		if (err)
1752			break;
1753		path[k].p_idx->ei_block = border;
1754		err = ext4_ext_dirty(handle, inode, path + k);
1755		if (err)
1756			break;
1757	}
1758
1759	return err;
1760}
1761
1762static int ext4_can_extents_be_merged(struct inode *inode,
1763				      struct ext4_extent *ex1,
1764				      struct ext4_extent *ex2)
1765{
1766	unsigned short ext1_ee_len, ext2_ee_len;
1767
1768	if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1769		return 0;
1770
1771	ext1_ee_len = ext4_ext_get_actual_len(ex1);
1772	ext2_ee_len = ext4_ext_get_actual_len(ex2);
1773
1774	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1775			le32_to_cpu(ex2->ee_block))
1776		return 0;
1777
 
 
 
 
 
1778	if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1779		return 0;
1780
 
 
 
 
 
1781	if (ext4_ext_is_unwritten(ex1) &&
1782	    ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
 
 
1783		return 0;
1784#ifdef AGGRESSIVE_TEST
1785	if (ext1_ee_len >= 4)
1786		return 0;
1787#endif
1788
1789	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1790		return 1;
1791	return 0;
1792}
1793
1794/*
1795 * This function tries to merge the "ex" extent to the next extent in the tree.
1796 * It always tries to merge towards right. If you want to merge towards
1797 * left, pass "ex - 1" as argument instead of "ex".
1798 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1799 * 1 if they got merged.
1800 */
1801static int ext4_ext_try_to_merge_right(struct inode *inode,
1802				 struct ext4_ext_path *path,
1803				 struct ext4_extent *ex)
1804{
1805	struct ext4_extent_header *eh;
1806	unsigned int depth, len;
1807	int merge_done = 0, unwritten;
1808
1809	depth = ext_depth(inode);
1810	BUG_ON(path[depth].p_hdr == NULL);
1811	eh = path[depth].p_hdr;
1812
1813	while (ex < EXT_LAST_EXTENT(eh)) {
1814		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1815			break;
1816		/* merge with next extent! */
1817		unwritten = ext4_ext_is_unwritten(ex);
1818		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1819				+ ext4_ext_get_actual_len(ex + 1));
1820		if (unwritten)
1821			ext4_ext_mark_unwritten(ex);
1822
1823		if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1824			len = (EXT_LAST_EXTENT(eh) - ex - 1)
1825				* sizeof(struct ext4_extent);
1826			memmove(ex + 1, ex + 2, len);
1827		}
1828		le16_add_cpu(&eh->eh_entries, -1);
1829		merge_done = 1;
1830		WARN_ON(eh->eh_entries == 0);
1831		if (!eh->eh_entries)
1832			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1833	}
1834
1835	return merge_done;
1836}
1837
1838/*
1839 * This function does a very simple check to see if we can collapse
1840 * an extent tree with a single extent tree leaf block into the inode.
1841 */
1842static void ext4_ext_try_to_merge_up(handle_t *handle,
1843				     struct inode *inode,
1844				     struct ext4_ext_path *path)
1845{
1846	size_t s;
1847	unsigned max_root = ext4_ext_space_root(inode, 0);
1848	ext4_fsblk_t blk;
1849
1850	if ((path[0].p_depth != 1) ||
1851	    (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1852	    (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1853		return;
1854
1855	/*
1856	 * We need to modify the block allocation bitmap and the block
1857	 * group descriptor to release the extent tree block.  If we
1858	 * can't get the journal credits, give up.
1859	 */
1860	if (ext4_journal_extend(handle, 2,
1861			ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1862		return;
1863
1864	/*
1865	 * Copy the extent data up to the inode
1866	 */
1867	blk = ext4_idx_pblock(path[0].p_idx);
1868	s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1869		sizeof(struct ext4_extent_idx);
1870	s += sizeof(struct ext4_extent_header);
1871
1872	path[1].p_maxdepth = path[0].p_maxdepth;
1873	memcpy(path[0].p_hdr, path[1].p_hdr, s);
1874	path[0].p_depth = 0;
1875	path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1876		(path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1877	path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1878
1879	brelse(path[1].p_bh);
1880	ext4_free_blocks(handle, inode, NULL, blk, 1,
1881			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1882}
1883
1884/*
1885 * This function tries to merge the @ex extent to neighbours in the tree, then
1886 * tries to collapse the extent tree into the inode.
1887 */
1888static void ext4_ext_try_to_merge(handle_t *handle,
1889				  struct inode *inode,
1890				  struct ext4_ext_path *path,
1891				  struct ext4_extent *ex)
1892{
1893	struct ext4_extent_header *eh;
1894	unsigned int depth;
1895	int merge_done = 0;
1896
1897	depth = ext_depth(inode);
1898	BUG_ON(path[depth].p_hdr == NULL);
1899	eh = path[depth].p_hdr;
1900
1901	if (ex > EXT_FIRST_EXTENT(eh))
1902		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1903
1904	if (!merge_done)
1905		(void) ext4_ext_try_to_merge_right(inode, path, ex);
1906
1907	ext4_ext_try_to_merge_up(handle, inode, path);
1908}
1909
1910/*
1911 * check if a portion of the "newext" extent overlaps with an
1912 * existing extent.
1913 *
1914 * If there is an overlap discovered, it updates the length of the newext
1915 * such that there will be no overlap, and then returns 1.
1916 * If there is no overlap found, it returns 0.
1917 */
1918static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1919					   struct inode *inode,
1920					   struct ext4_extent *newext,
1921					   struct ext4_ext_path *path)
1922{
1923	ext4_lblk_t b1, b2;
1924	unsigned int depth, len1;
1925	unsigned int ret = 0;
1926
1927	b1 = le32_to_cpu(newext->ee_block);
1928	len1 = ext4_ext_get_actual_len(newext);
1929	depth = ext_depth(inode);
1930	if (!path[depth].p_ext)
1931		goto out;
1932	b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1933
1934	/*
1935	 * get the next allocated block if the extent in the path
1936	 * is before the requested block(s)
1937	 */
1938	if (b2 < b1) {
1939		b2 = ext4_ext_next_allocated_block(path);
1940		if (b2 == EXT_MAX_BLOCKS)
1941			goto out;
1942		b2 = EXT4_LBLK_CMASK(sbi, b2);
1943	}
1944
1945	/* check for wrap through zero on extent logical start block*/
1946	if (b1 + len1 < b1) {
1947		len1 = EXT_MAX_BLOCKS - b1;
1948		newext->ee_len = cpu_to_le16(len1);
1949		ret = 1;
1950	}
1951
1952	/* check for overlap */
1953	if (b1 + len1 > b2) {
1954		newext->ee_len = cpu_to_le16(b2 - b1);
1955		ret = 1;
1956	}
1957out:
1958	return ret;
1959}
1960
1961/*
1962 * ext4_ext_insert_extent:
1963 * tries to merge requested extent into the existing extent or
1964 * inserts requested extent as new one into the tree,
1965 * creating new leaf in the no-space case.
1966 */
1967int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1968				struct ext4_ext_path **ppath,
1969				struct ext4_extent *newext, int gb_flags)
1970{
1971	struct ext4_ext_path *path = *ppath;
1972	struct ext4_extent_header *eh;
1973	struct ext4_extent *ex, *fex;
1974	struct ext4_extent *nearex; /* nearest extent */
1975	struct ext4_ext_path *npath = NULL;
1976	int depth, len, err;
1977	ext4_lblk_t next;
1978	int mb_flags = 0, unwritten;
1979
1980	if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1981		mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1982	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1983		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1984		return -EFSCORRUPTED;
1985	}
1986	depth = ext_depth(inode);
1987	ex = path[depth].p_ext;
1988	eh = path[depth].p_hdr;
1989	if (unlikely(path[depth].p_hdr == NULL)) {
1990		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1991		return -EFSCORRUPTED;
1992	}
1993
1994	/* try to insert block into found extent and return */
1995	if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1996
1997		/*
1998		 * Try to see whether we should rather test the extent on
1999		 * right from ex, or from the left of ex. This is because
2000		 * ext4_find_extent() can return either extent on the
2001		 * left, or on the right from the searched position. This
2002		 * will make merging more effective.
2003		 */
2004		if (ex < EXT_LAST_EXTENT(eh) &&
2005		    (le32_to_cpu(ex->ee_block) +
2006		    ext4_ext_get_actual_len(ex) <
2007		    le32_to_cpu(newext->ee_block))) {
2008			ex += 1;
2009			goto prepend;
2010		} else if ((ex > EXT_FIRST_EXTENT(eh)) &&
2011			   (le32_to_cpu(newext->ee_block) +
2012			   ext4_ext_get_actual_len(newext) <
2013			   le32_to_cpu(ex->ee_block)))
2014			ex -= 1;
2015
2016		/* Try to append newex to the ex */
2017		if (ext4_can_extents_be_merged(inode, ex, newext)) {
2018			ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
2019				  "(from %llu)\n",
2020				  ext4_ext_is_unwritten(newext),
2021				  ext4_ext_get_actual_len(newext),
2022				  le32_to_cpu(ex->ee_block),
2023				  ext4_ext_is_unwritten(ex),
2024				  ext4_ext_get_actual_len(ex),
2025				  ext4_ext_pblock(ex));
2026			err = ext4_ext_get_access(handle, inode,
2027						  path + depth);
2028			if (err)
2029				return err;
2030			unwritten = ext4_ext_is_unwritten(ex);
2031			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2032					+ ext4_ext_get_actual_len(newext));
2033			if (unwritten)
2034				ext4_ext_mark_unwritten(ex);
 
2035			nearex = ex;
2036			goto merge;
2037		}
2038
2039prepend:
2040		/* Try to prepend newex to the ex */
2041		if (ext4_can_extents_be_merged(inode, newext, ex)) {
2042			ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
2043				  "(from %llu)\n",
2044				  le32_to_cpu(newext->ee_block),
2045				  ext4_ext_is_unwritten(newext),
2046				  ext4_ext_get_actual_len(newext),
2047				  le32_to_cpu(ex->ee_block),
2048				  ext4_ext_is_unwritten(ex),
2049				  ext4_ext_get_actual_len(ex),
2050				  ext4_ext_pblock(ex));
2051			err = ext4_ext_get_access(handle, inode,
2052						  path + depth);
2053			if (err)
2054				return err;
2055
2056			unwritten = ext4_ext_is_unwritten(ex);
2057			ex->ee_block = newext->ee_block;
2058			ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2059			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2060					+ ext4_ext_get_actual_len(newext));
2061			if (unwritten)
2062				ext4_ext_mark_unwritten(ex);
 
2063			nearex = ex;
2064			goto merge;
2065		}
2066	}
2067
2068	depth = ext_depth(inode);
2069	eh = path[depth].p_hdr;
2070	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2071		goto has_space;
2072
2073	/* probably next leaf has space for us? */
2074	fex = EXT_LAST_EXTENT(eh);
2075	next = EXT_MAX_BLOCKS;
2076	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2077		next = ext4_ext_next_leaf_block(path);
2078	if (next != EXT_MAX_BLOCKS) {
2079		ext_debug(inode, "next leaf block - %u\n", next);
2080		BUG_ON(npath != NULL);
2081		npath = ext4_find_extent(inode, next, NULL, gb_flags);
2082		if (IS_ERR(npath))
2083			return PTR_ERR(npath);
2084		BUG_ON(npath->p_depth != path->p_depth);
2085		eh = npath[depth].p_hdr;
2086		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2087			ext_debug(inode, "next leaf isn't full(%d)\n",
2088				  le16_to_cpu(eh->eh_entries));
2089			path = npath;
2090			goto has_space;
2091		}
2092		ext_debug(inode, "next leaf has no free space(%d,%d)\n",
2093			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2094	}
2095
2096	/*
2097	 * There is no free space in the found leaf.
2098	 * We're gonna add a new leaf in the tree.
2099	 */
2100	if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2101		mb_flags |= EXT4_MB_USE_RESERVED;
2102	err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2103				       ppath, newext);
2104	if (err)
2105		goto cleanup;
2106	depth = ext_depth(inode);
2107	eh = path[depth].p_hdr;
2108
2109has_space:
2110	nearex = path[depth].p_ext;
2111
2112	err = ext4_ext_get_access(handle, inode, path + depth);
2113	if (err)
2114		goto cleanup;
2115
2116	if (!nearex) {
2117		/* there is no extent in this leaf, create first one */
2118		ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
2119				le32_to_cpu(newext->ee_block),
2120				ext4_ext_pblock(newext),
2121				ext4_ext_is_unwritten(newext),
2122				ext4_ext_get_actual_len(newext));
2123		nearex = EXT_FIRST_EXTENT(eh);
2124	} else {
2125		if (le32_to_cpu(newext->ee_block)
2126			   > le32_to_cpu(nearex->ee_block)) {
2127			/* Insert after */
2128			ext_debug(inode, "insert %u:%llu:[%d]%d before: "
2129					"nearest %p\n",
2130					le32_to_cpu(newext->ee_block),
2131					ext4_ext_pblock(newext),
2132					ext4_ext_is_unwritten(newext),
2133					ext4_ext_get_actual_len(newext),
2134					nearex);
2135			nearex++;
2136		} else {
2137			/* Insert before */
2138			BUG_ON(newext->ee_block == nearex->ee_block);
2139			ext_debug(inode, "insert %u:%llu:[%d]%d after: "
2140					"nearest %p\n",
2141					le32_to_cpu(newext->ee_block),
2142					ext4_ext_pblock(newext),
2143					ext4_ext_is_unwritten(newext),
2144					ext4_ext_get_actual_len(newext),
2145					nearex);
2146		}
2147		len = EXT_LAST_EXTENT(eh) - nearex + 1;
2148		if (len > 0) {
2149			ext_debug(inode, "insert %u:%llu:[%d]%d: "
2150					"move %d extents from 0x%p to 0x%p\n",
2151					le32_to_cpu(newext->ee_block),
2152					ext4_ext_pblock(newext),
2153					ext4_ext_is_unwritten(newext),
2154					ext4_ext_get_actual_len(newext),
2155					len, nearex, nearex + 1);
2156			memmove(nearex + 1, nearex,
2157				len * sizeof(struct ext4_extent));
2158		}
2159	}
2160
2161	le16_add_cpu(&eh->eh_entries, 1);
2162	path[depth].p_ext = nearex;
2163	nearex->ee_block = newext->ee_block;
2164	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2165	nearex->ee_len = newext->ee_len;
2166
2167merge:
2168	/* try to merge extents */
2169	if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2170		ext4_ext_try_to_merge(handle, inode, path, nearex);
2171
2172
2173	/* time to correct all indexes above */
2174	err = ext4_ext_correct_indexes(handle, inode, path);
2175	if (err)
2176		goto cleanup;
2177
2178	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2179
2180cleanup:
2181	ext4_free_ext_path(npath);
 
2182	return err;
2183}
2184
2185static int ext4_fill_es_cache_info(struct inode *inode,
2186				   ext4_lblk_t block, ext4_lblk_t num,
2187				   struct fiemap_extent_info *fieinfo)
2188{
2189	ext4_lblk_t next, end = block + num - 1;
 
2190	struct extent_status es;
 
 
 
 
2191	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2192	unsigned int flags;
2193	int err;
2194
2195	while (block <= end) {
2196		next = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2197		flags = 0;
2198		if (!ext4_es_lookup_extent(inode, block, &next, &es))
2199			break;
2200		if (ext4_es_is_unwritten(&es))
2201			flags |= FIEMAP_EXTENT_UNWRITTEN;
2202		if (ext4_es_is_delayed(&es))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2203			flags |= (FIEMAP_EXTENT_DELALLOC |
2204				  FIEMAP_EXTENT_UNKNOWN);
2205		if (ext4_es_is_hole(&es))
2206			flags |= EXT4_FIEMAP_EXTENT_HOLE;
2207		if (next == 0)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2208			flags |= FIEMAP_EXTENT_LAST;
2209		if (flags & (FIEMAP_EXTENT_DELALLOC|
2210			     EXT4_FIEMAP_EXTENT_HOLE))
2211			es.es_pblk = 0;
2212		else
2213			es.es_pblk = ext4_es_pblock(&es);
2214		err = fiemap_fill_next_extent(fieinfo,
 
 
 
 
 
 
 
2215				(__u64)es.es_lblk << blksize_bits,
2216				(__u64)es.es_pblk << blksize_bits,
2217				(__u64)es.es_len << blksize_bits,
2218				flags);
2219		if (next == 0)
2220			break;
2221		block = next;
2222		if (err < 0)
2223			return err;
2224		if (err == 1)
2225			return 0;
 
 
2226	}
2227	return 0;
 
 
 
2228}
2229
2230
2231/*
2232 * ext4_ext_find_hole - find hole around given block according to the given path
2233 * @inode:	inode we lookup in
2234 * @path:	path in extent tree to @lblk
2235 * @lblk:	pointer to logical block around which we want to determine hole
2236 *
2237 * Determine hole length (and start if easily possible) around given logical
2238 * block. We don't try too hard to find the beginning of the hole but @path
2239 * actually points to extent before @lblk, we provide it.
2240 *
2241 * The function returns the length of a hole starting at @lblk. We update @lblk
2242 * to the beginning of the hole if we managed to find it.
2243 */
2244static ext4_lblk_t ext4_ext_find_hole(struct inode *inode,
2245				      struct ext4_ext_path *path,
2246				      ext4_lblk_t *lblk)
2247{
2248	int depth = ext_depth(inode);
2249	struct ext4_extent *ex;
2250	ext4_lblk_t len;
2251
2252	ex = path[depth].p_ext;
2253	if (ex == NULL) {
2254		/* there is no extent yet, so gap is [0;-] */
2255		*lblk = 0;
2256		len = EXT_MAX_BLOCKS;
2257	} else if (*lblk < le32_to_cpu(ex->ee_block)) {
2258		len = le32_to_cpu(ex->ee_block) - *lblk;
2259	} else if (*lblk >= le32_to_cpu(ex->ee_block)
2260			+ ext4_ext_get_actual_len(ex)) {
2261		ext4_lblk_t next;
2262
2263		*lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2264		next = ext4_ext_next_allocated_block(path);
2265		BUG_ON(next == *lblk);
2266		len = next - *lblk;
2267	} else {
2268		BUG();
2269	}
2270	return len;
2271}
2272
2273/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2274 * ext4_ext_rm_idx:
2275 * removes index from the index block.
2276 */
2277static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2278			struct ext4_ext_path *path, int depth)
2279{
2280	int err;
2281	ext4_fsblk_t leaf;
2282
2283	/* free index block */
2284	depth--;
2285	path = path + depth;
2286	leaf = ext4_idx_pblock(path->p_idx);
2287	if (unlikely(path->p_hdr->eh_entries == 0)) {
2288		EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2289		return -EFSCORRUPTED;
2290	}
2291	err = ext4_ext_get_access(handle, inode, path);
2292	if (err)
2293		return err;
2294
2295	if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2296		int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2297		len *= sizeof(struct ext4_extent_idx);
2298		memmove(path->p_idx, path->p_idx + 1, len);
2299	}
2300
2301	le16_add_cpu(&path->p_hdr->eh_entries, -1);
2302	err = ext4_ext_dirty(handle, inode, path);
2303	if (err)
2304		return err;
2305	ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2306	trace_ext4_ext_rm_idx(inode, leaf);
2307
2308	ext4_free_blocks(handle, inode, NULL, leaf, 1,
2309			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2310
2311	while (--depth >= 0) {
2312		if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2313			break;
2314		path--;
2315		err = ext4_ext_get_access(handle, inode, path);
2316		if (err)
2317			break;
2318		path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2319		err = ext4_ext_dirty(handle, inode, path);
2320		if (err)
2321			break;
2322	}
2323	return err;
2324}
2325
2326/*
2327 * ext4_ext_calc_credits_for_single_extent:
2328 * This routine returns max. credits that needed to insert an extent
2329 * to the extent tree.
2330 * When pass the actual path, the caller should calculate credits
2331 * under i_data_sem.
2332 */
2333int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2334						struct ext4_ext_path *path)
2335{
2336	if (path) {
2337		int depth = ext_depth(inode);
2338		int ret = 0;
2339
2340		/* probably there is space in leaf? */
2341		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2342				< le16_to_cpu(path[depth].p_hdr->eh_max)) {
2343
2344			/*
2345			 *  There are some space in the leaf tree, no
2346			 *  need to account for leaf block credit
2347			 *
2348			 *  bitmaps and block group descriptor blocks
2349			 *  and other metadata blocks still need to be
2350			 *  accounted.
2351			 */
2352			/* 1 bitmap, 1 block group descriptor */
2353			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2354			return ret;
2355		}
2356	}
2357
2358	return ext4_chunk_trans_blocks(inode, nrblocks);
2359}
2360
2361/*
2362 * How many index/leaf blocks need to change/allocate to add @extents extents?
2363 *
2364 * If we add a single extent, then in the worse case, each tree level
2365 * index/leaf need to be changed in case of the tree split.
2366 *
2367 * If more extents are inserted, they could cause the whole tree split more
2368 * than once, but this is really rare.
2369 */
2370int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2371{
2372	int index;
2373	int depth;
2374
2375	/* If we are converting the inline data, only one is needed here. */
2376	if (ext4_has_inline_data(inode))
2377		return 1;
2378
2379	depth = ext_depth(inode);
2380
2381	if (extents <= 1)
2382		index = depth * 2;
2383	else
2384		index = depth * 3;
2385
2386	return index;
2387}
2388
2389static inline int get_default_free_blocks_flags(struct inode *inode)
2390{
2391	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2392	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2393		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2394	else if (ext4_should_journal_data(inode))
2395		return EXT4_FREE_BLOCKS_FORGET;
2396	return 0;
2397}
2398
2399/*
2400 * ext4_rereserve_cluster - increment the reserved cluster count when
2401 *                          freeing a cluster with a pending reservation
2402 *
2403 * @inode - file containing the cluster
2404 * @lblk - logical block in cluster to be reserved
2405 *
2406 * Increments the reserved cluster count and adjusts quota in a bigalloc
2407 * file system when freeing a partial cluster containing at least one
2408 * delayed and unwritten block.  A partial cluster meeting that
2409 * requirement will have a pending reservation.  If so, the
2410 * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2411 * defer reserved and allocated space accounting to a subsequent call
2412 * to this function.
2413 */
2414static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2415{
2416	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2417	struct ext4_inode_info *ei = EXT4_I(inode);
2418
2419	dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2420
2421	spin_lock(&ei->i_block_reservation_lock);
2422	ei->i_reserved_data_blocks++;
2423	percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2424	spin_unlock(&ei->i_block_reservation_lock);
2425
2426	percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2427	ext4_remove_pending(inode, lblk);
2428}
2429
2430static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2431			      struct ext4_extent *ex,
2432			      struct partial_cluster *partial,
2433			      ext4_lblk_t from, ext4_lblk_t to)
2434{
2435	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2436	unsigned short ee_len = ext4_ext_get_actual_len(ex);
2437	ext4_fsblk_t last_pblk, pblk;
2438	ext4_lblk_t num;
2439	int flags;
2440
2441	/* only extent tail removal is allowed */
2442	if (from < le32_to_cpu(ex->ee_block) ||
2443	    to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2444		ext4_error(sbi->s_sb,
2445			   "strange request: removal(2) %u-%u from %u:%u",
2446			   from, to, le32_to_cpu(ex->ee_block), ee_len);
2447		return 0;
2448	}
2449
2450#ifdef EXTENTS_STATS
2451	spin_lock(&sbi->s_ext_stats_lock);
2452	sbi->s_ext_blocks += ee_len;
2453	sbi->s_ext_extents++;
2454	if (ee_len < sbi->s_ext_min)
2455		sbi->s_ext_min = ee_len;
2456	if (ee_len > sbi->s_ext_max)
2457		sbi->s_ext_max = ee_len;
2458	if (ext_depth(inode) > sbi->s_depth_max)
2459		sbi->s_depth_max = ext_depth(inode);
2460	spin_unlock(&sbi->s_ext_stats_lock);
2461#endif
2462
2463	trace_ext4_remove_blocks(inode, ex, from, to, partial);
2464
2465	/*
2466	 * if we have a partial cluster, and it's different from the
2467	 * cluster of the last block in the extent, we free it
 
 
 
2468	 */
2469	last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2470
2471	if (partial->state != initial &&
2472	    partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2473		if (partial->state == tofree) {
2474			flags = get_default_free_blocks_flags(inode);
2475			if (ext4_is_pending(inode, partial->lblk))
2476				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2477			ext4_free_blocks(handle, inode, NULL,
2478					 EXT4_C2B(sbi, partial->pclu),
2479					 sbi->s_cluster_ratio, flags);
2480			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2481				ext4_rereserve_cluster(inode, partial->lblk);
2482		}
2483		partial->state = initial;
2484	}
2485
2486	num = le32_to_cpu(ex->ee_block) + ee_len - from;
2487	pblk = ext4_ext_pblock(ex) + ee_len - num;
2488
 
2489	/*
2490	 * We free the partial cluster at the end of the extent (if any),
2491	 * unless the cluster is used by another extent (partial_cluster
2492	 * state is nofree).  If a partial cluster exists here, it must be
2493	 * shared with the last block in the extent.
2494	 */
2495	flags = get_default_free_blocks_flags(inode);
2496
2497	/* partial, left end cluster aligned, right end unaligned */
2498	if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2499	    (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2500	    (partial->state != nofree)) {
2501		if (ext4_is_pending(inode, to))
2502			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2503		ext4_free_blocks(handle, inode, NULL,
2504				 EXT4_PBLK_CMASK(sbi, last_pblk),
2505				 sbi->s_cluster_ratio, flags);
2506		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2507			ext4_rereserve_cluster(inode, to);
2508		partial->state = initial;
2509		flags = get_default_free_blocks_flags(inode);
2510	}
2511
2512	flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2513
2514	/*
2515	 * For bigalloc file systems, we never free a partial cluster
2516	 * at the beginning of the extent.  Instead, we check to see if we
2517	 * need to free it on a subsequent call to ext4_remove_blocks,
2518	 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2519	 */
2520	flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2521	ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2522
2523	/* reset the partial cluster if we've freed past it */
2524	if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2525		partial->state = initial;
2526
2527	/*
2528	 * If we've freed the entire extent but the beginning is not left
2529	 * cluster aligned and is not marked as ineligible for freeing we
2530	 * record the partial cluster at the beginning of the extent.  It
2531	 * wasn't freed by the preceding ext4_free_blocks() call, and we
2532	 * need to look farther to the left to determine if it's to be freed
2533	 * (not shared with another extent). Else, reset the partial
2534	 * cluster - we're either  done freeing or the beginning of the
2535	 * extent is left cluster aligned.
2536	 */
2537	if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2538		if (partial->state == initial) {
2539			partial->pclu = EXT4_B2C(sbi, pblk);
2540			partial->lblk = from;
2541			partial->state = tofree;
 
 
 
 
 
 
 
 
2542		}
2543	} else {
2544		partial->state = initial;
2545	}
2546
2547	return 0;
2548}
2549
 
2550/*
2551 * ext4_ext_rm_leaf() Removes the extents associated with the
2552 * blocks appearing between "start" and "end".  Both "start"
2553 * and "end" must appear in the same extent or EIO is returned.
2554 *
2555 * @handle: The journal handle
2556 * @inode:  The files inode
2557 * @path:   The path to the leaf
2558 * @partial_cluster: The cluster which we'll have to free if all extents
2559 *                   has been released from it.  However, if this value is
2560 *                   negative, it's a cluster just to the right of the
2561 *                   punched region and it must not be freed.
2562 * @start:  The first block to remove
2563 * @end:   The last block to remove
2564 */
2565static int
2566ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2567		 struct ext4_ext_path *path,
2568		 struct partial_cluster *partial,
2569		 ext4_lblk_t start, ext4_lblk_t end)
2570{
2571	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2572	int err = 0, correct_index = 0;
2573	int depth = ext_depth(inode), credits, revoke_credits;
2574	struct ext4_extent_header *eh;
2575	ext4_lblk_t a, b;
2576	unsigned num;
2577	ext4_lblk_t ex_ee_block;
2578	unsigned short ex_ee_len;
2579	unsigned unwritten = 0;
2580	struct ext4_extent *ex;
2581	ext4_fsblk_t pblk;
2582
2583	/* the header must be checked already in ext4_ext_remove_space() */
2584	ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2585	if (!path[depth].p_hdr)
2586		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2587	eh = path[depth].p_hdr;
2588	if (unlikely(path[depth].p_hdr == NULL)) {
2589		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2590		return -EFSCORRUPTED;
2591	}
2592	/* find where to start removing */
2593	ex = path[depth].p_ext;
2594	if (!ex)
2595		ex = EXT_LAST_EXTENT(eh);
2596
2597	ex_ee_block = le32_to_cpu(ex->ee_block);
2598	ex_ee_len = ext4_ext_get_actual_len(ex);
2599
2600	trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2601
2602	while (ex >= EXT_FIRST_EXTENT(eh) &&
2603			ex_ee_block + ex_ee_len > start) {
2604
2605		if (ext4_ext_is_unwritten(ex))
2606			unwritten = 1;
2607		else
2608			unwritten = 0;
2609
2610		ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2611			  unwritten, ex_ee_len);
2612		path[depth].p_ext = ex;
2613
2614		a = max(ex_ee_block, start);
2615		b = min(ex_ee_block + ex_ee_len - 1, end);
 
2616
2617		ext_debug(inode, "  border %u:%u\n", a, b);
2618
2619		/* If this extent is beyond the end of the hole, skip it */
2620		if (end < ex_ee_block) {
2621			/*
2622			 * We're going to skip this extent and move to another,
2623			 * so note that its first cluster is in use to avoid
2624			 * freeing it when removing blocks.  Eventually, the
2625			 * right edge of the truncated/punched region will
2626			 * be just to the left.
2627			 */
2628			if (sbi->s_cluster_ratio > 1) {
2629				pblk = ext4_ext_pblock(ex);
2630				partial->pclu = EXT4_B2C(sbi, pblk);
2631				partial->state = nofree;
2632			}
2633			ex--;
2634			ex_ee_block = le32_to_cpu(ex->ee_block);
2635			ex_ee_len = ext4_ext_get_actual_len(ex);
2636			continue;
2637		} else if (b != ex_ee_block + ex_ee_len - 1) {
2638			EXT4_ERROR_INODE(inode,
2639					 "can not handle truncate %u:%u "
2640					 "on extent %u:%u",
2641					 start, end, ex_ee_block,
2642					 ex_ee_block + ex_ee_len - 1);
2643			err = -EFSCORRUPTED;
2644			goto out;
2645		} else if (a != ex_ee_block) {
2646			/* remove tail of the extent */
2647			num = a - ex_ee_block;
2648		} else {
2649			/* remove whole extent: excellent! */
2650			num = 0;
2651		}
2652		/*
2653		 * 3 for leaf, sb, and inode plus 2 (bmap and group
2654		 * descriptor) for each block group; assume two block
2655		 * groups plus ex_ee_len/blocks_per_block_group for
2656		 * the worst case
2657		 */
2658		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2659		if (ex == EXT_FIRST_EXTENT(eh)) {
2660			correct_index = 1;
2661			credits += (ext_depth(inode)) + 1;
2662		}
2663		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2664		/*
2665		 * We may end up freeing some index blocks and data from the
2666		 * punched range. Note that partial clusters are accounted for
2667		 * by ext4_free_data_revoke_credits().
2668		 */
2669		revoke_credits =
2670			ext4_free_metadata_revoke_credits(inode->i_sb,
2671							  ext_depth(inode)) +
2672			ext4_free_data_revoke_credits(inode, b - a + 1);
2673
2674		err = ext4_datasem_ensure_credits(handle, inode, credits,
2675						  credits, revoke_credits);
2676		if (err) {
2677			if (err > 0)
2678				err = -EAGAIN;
2679			goto out;
2680		}
2681
2682		err = ext4_ext_get_access(handle, inode, path + depth);
2683		if (err)
2684			goto out;
2685
2686		err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
 
2687		if (err)
2688			goto out;
2689
2690		if (num == 0)
2691			/* this extent is removed; mark slot entirely unused */
2692			ext4_ext_store_pblock(ex, 0);
2693
2694		ex->ee_len = cpu_to_le16(num);
2695		/*
2696		 * Do not mark unwritten if all the blocks in the
2697		 * extent have been removed.
2698		 */
2699		if (unwritten && num)
2700			ext4_ext_mark_unwritten(ex);
2701		/*
2702		 * If the extent was completely released,
2703		 * we need to remove it from the leaf
2704		 */
2705		if (num == 0) {
2706			if (end != EXT_MAX_BLOCKS - 1) {
2707				/*
2708				 * For hole punching, we need to scoot all the
2709				 * extents up when an extent is removed so that
2710				 * we dont have blank extents in the middle
2711				 */
2712				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2713					sizeof(struct ext4_extent));
2714
2715				/* Now get rid of the one at the end */
2716				memset(EXT_LAST_EXTENT(eh), 0,
2717					sizeof(struct ext4_extent));
2718			}
2719			le16_add_cpu(&eh->eh_entries, -1);
2720		}
2721
2722		err = ext4_ext_dirty(handle, inode, path + depth);
2723		if (err)
2724			goto out;
2725
2726		ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2727				ext4_ext_pblock(ex));
2728		ex--;
2729		ex_ee_block = le32_to_cpu(ex->ee_block);
2730		ex_ee_len = ext4_ext_get_actual_len(ex);
2731	}
2732
2733	if (correct_index && eh->eh_entries)
2734		err = ext4_ext_correct_indexes(handle, inode, path);
2735
2736	/*
2737	 * If there's a partial cluster and at least one extent remains in
2738	 * the leaf, free the partial cluster if it isn't shared with the
2739	 * current extent.  If it is shared with the current extent
2740	 * we reset the partial cluster because we've reached the start of the
2741	 * truncated/punched region and we're done removing blocks.
2742	 */
2743	if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2744		pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2745		if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2746			int flags = get_default_free_blocks_flags(inode);
2747
2748			if (ext4_is_pending(inode, partial->lblk))
2749				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2750			ext4_free_blocks(handle, inode, NULL,
2751					 EXT4_C2B(sbi, partial->pclu),
2752					 sbi->s_cluster_ratio, flags);
2753			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2754				ext4_rereserve_cluster(inode, partial->lblk);
2755		}
2756		partial->state = initial;
2757	}
2758
2759	/* if this leaf is free, then we should
2760	 * remove it from index block above */
2761	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2762		err = ext4_ext_rm_idx(handle, inode, path, depth);
2763
2764out:
2765	return err;
2766}
2767
2768/*
2769 * ext4_ext_more_to_rm:
2770 * returns 1 if current index has to be freed (even partial)
2771 */
2772static int
2773ext4_ext_more_to_rm(struct ext4_ext_path *path)
2774{
2775	BUG_ON(path->p_idx == NULL);
2776
2777	if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2778		return 0;
2779
2780	/*
2781	 * if truncate on deeper level happened, it wasn't partial,
2782	 * so we have to consider current index for truncation
2783	 */
2784	if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2785		return 0;
2786	return 1;
2787}
2788
2789int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2790			  ext4_lblk_t end)
2791{
2792	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2793	int depth = ext_depth(inode);
2794	struct ext4_ext_path *path = NULL;
2795	struct partial_cluster partial;
2796	handle_t *handle;
2797	int i = 0, err = 0;
2798
2799	partial.pclu = 0;
2800	partial.lblk = 0;
2801	partial.state = initial;
2802
2803	ext_debug(inode, "truncate since %u to %u\n", start, end);
2804
2805	/* probably first extent we're gonna free will be last in block */
2806	handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2807			depth + 1,
2808			ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2809	if (IS_ERR(handle))
2810		return PTR_ERR(handle);
2811
2812again:
2813	trace_ext4_ext_remove_space(inode, start, end, depth);
2814
2815	/*
2816	 * Check if we are removing extents inside the extent tree. If that
2817	 * is the case, we are going to punch a hole inside the extent tree
2818	 * so we have to check whether we need to split the extent covering
2819	 * the last block to remove so we can easily remove the part of it
2820	 * in ext4_ext_rm_leaf().
2821	 */
2822	if (end < EXT_MAX_BLOCKS - 1) {
2823		struct ext4_extent *ex;
2824		ext4_lblk_t ee_block, ex_end, lblk;
2825		ext4_fsblk_t pblk;
2826
2827		/* find extent for or closest extent to this block */
2828		path = ext4_find_extent(inode, end, NULL,
2829					EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2830		if (IS_ERR(path)) {
2831			ext4_journal_stop(handle);
2832			return PTR_ERR(path);
2833		}
2834		depth = ext_depth(inode);
2835		/* Leaf not may not exist only if inode has no blocks at all */
2836		ex = path[depth].p_ext;
2837		if (!ex) {
2838			if (depth) {
2839				EXT4_ERROR_INODE(inode,
2840						 "path[%d].p_hdr == NULL",
2841						 depth);
2842				err = -EFSCORRUPTED;
2843			}
2844			goto out;
2845		}
2846
2847		ee_block = le32_to_cpu(ex->ee_block);
2848		ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2849
2850		/*
2851		 * See if the last block is inside the extent, if so split
2852		 * the extent at 'end' block so we can easily remove the
2853		 * tail of the first part of the split extent in
2854		 * ext4_ext_rm_leaf().
2855		 */
2856		if (end >= ee_block && end < ex_end) {
2857
2858			/*
2859			 * If we're going to split the extent, note that
2860			 * the cluster containing the block after 'end' is
2861			 * in use to avoid freeing it when removing blocks.
2862			 */
2863			if (sbi->s_cluster_ratio > 1) {
2864				pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2865				partial.pclu = EXT4_B2C(sbi, pblk);
2866				partial.state = nofree;
2867			}
2868
2869			/*
2870			 * Split the extent in two so that 'end' is the last
2871			 * block in the first new extent. Also we should not
2872			 * fail removing space due to ENOSPC so try to use
2873			 * reserved block if that happens.
2874			 */
2875			err = ext4_force_split_extent_at(handle, inode, &path,
2876							 end + 1, 1);
2877			if (err < 0)
2878				goto out;
2879
2880		} else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2881			   partial.state == initial) {
2882			/*
2883			 * If we're punching, there's an extent to the right.
2884			 * If the partial cluster hasn't been set, set it to
2885			 * that extent's first cluster and its state to nofree
2886			 * so it won't be freed should it contain blocks to be
2887			 * removed. If it's already set (tofree/nofree), we're
2888			 * retrying and keep the original partial cluster info
2889			 * so a cluster marked tofree as a result of earlier
2890			 * extent removal is not lost.
2891			 */
2892			lblk = ex_end + 1;
2893			err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2894						    NULL);
2895			if (err < 0)
2896				goto out;
2897			if (pblk) {
2898				partial.pclu = EXT4_B2C(sbi, pblk);
2899				partial.state = nofree;
2900			}
2901		}
2902	}
2903	/*
2904	 * We start scanning from right side, freeing all the blocks
2905	 * after i_size and walking into the tree depth-wise.
2906	 */
2907	depth = ext_depth(inode);
2908	if (path) {
2909		int k = i = depth;
2910		while (--k > 0)
2911			path[k].p_block =
2912				le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2913	} else {
2914		path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2915			       GFP_NOFS | __GFP_NOFAIL);
2916		if (path == NULL) {
2917			ext4_journal_stop(handle);
2918			return -ENOMEM;
2919		}
2920		path[0].p_maxdepth = path[0].p_depth = depth;
2921		path[0].p_hdr = ext_inode_hdr(inode);
2922		i = 0;
2923
2924		if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2925			err = -EFSCORRUPTED;
2926			goto out;
2927		}
2928	}
2929	err = 0;
2930
2931	while (i >= 0 && err == 0) {
2932		if (i == depth) {
2933			/* this is leaf block */
2934			err = ext4_ext_rm_leaf(handle, inode, path,
2935					       &partial, start, end);
 
2936			/* root level has p_bh == NULL, brelse() eats this */
2937			brelse(path[i].p_bh);
2938			path[i].p_bh = NULL;
2939			i--;
2940			continue;
2941		}
2942
2943		/* this is index block */
2944		if (!path[i].p_hdr) {
2945			ext_debug(inode, "initialize header\n");
2946			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2947		}
2948
2949		if (!path[i].p_idx) {
2950			/* this level hasn't been touched yet */
2951			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2952			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2953			ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2954				  path[i].p_hdr,
2955				  le16_to_cpu(path[i].p_hdr->eh_entries));
2956		} else {
2957			/* we were already here, see at next index */
2958			path[i].p_idx--;
2959		}
2960
2961		ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2962				i, EXT_FIRST_INDEX(path[i].p_hdr),
2963				path[i].p_idx);
2964		if (ext4_ext_more_to_rm(path + i)) {
2965			struct buffer_head *bh;
2966			/* go to the next level */
2967			ext_debug(inode, "move to level %d (block %llu)\n",
2968				  i + 1, ext4_idx_pblock(path[i].p_idx));
2969			memset(path + i + 1, 0, sizeof(*path));
2970			bh = read_extent_tree_block(inode, path[i].p_idx,
2971						    depth - i - 1,
2972						    EXT4_EX_NOCACHE);
2973			if (IS_ERR(bh)) {
2974				/* should we reset i_size? */
2975				err = PTR_ERR(bh);
2976				break;
2977			}
2978			/* Yield here to deal with large extent trees.
2979			 * Should be a no-op if we did IO above. */
2980			cond_resched();
2981			if (WARN_ON(i + 1 > depth)) {
2982				err = -EFSCORRUPTED;
2983				break;
2984			}
2985			path[i + 1].p_bh = bh;
2986
2987			/* save actual number of indexes since this
2988			 * number is changed at the next iteration */
2989			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2990			i++;
2991		} else {
2992			/* we finished processing this index, go up */
2993			if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2994				/* index is empty, remove it;
2995				 * handle must be already prepared by the
2996				 * truncatei_leaf() */
2997				err = ext4_ext_rm_idx(handle, inode, path, i);
2998			}
2999			/* root level has p_bh == NULL, brelse() eats this */
3000			brelse(path[i].p_bh);
3001			path[i].p_bh = NULL;
3002			i--;
3003			ext_debug(inode, "return to level %d\n", i);
3004		}
3005	}
3006
3007	trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3008					 path->p_hdr->eh_entries);
3009
3010	/*
3011	 * if there's a partial cluster and we have removed the first extent
3012	 * in the file, then we also free the partial cluster, if any
 
 
3013	 */
3014	if (partial.state == tofree && err == 0) {
3015		int flags = get_default_free_blocks_flags(inode);
3016
3017		if (ext4_is_pending(inode, partial.lblk))
3018			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3019		ext4_free_blocks(handle, inode, NULL,
3020				 EXT4_C2B(sbi, partial.pclu),
3021				 sbi->s_cluster_ratio, flags);
3022		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3023			ext4_rereserve_cluster(inode, partial.lblk);
3024		partial.state = initial;
3025	}
3026
3027	/* TODO: flexible tree reduction should be here */
3028	if (path->p_hdr->eh_entries == 0) {
3029		/*
3030		 * truncate to zero freed all the tree,
3031		 * so we need to correct eh_depth
3032		 */
3033		err = ext4_ext_get_access(handle, inode, path);
3034		if (err == 0) {
3035			ext_inode_hdr(inode)->eh_depth = 0;
3036			ext_inode_hdr(inode)->eh_max =
3037				cpu_to_le16(ext4_ext_space_root(inode, 0));
3038			err = ext4_ext_dirty(handle, inode, path);
3039		}
3040	}
3041out:
3042	ext4_free_ext_path(path);
 
3043	path = NULL;
3044	if (err == -EAGAIN)
3045		goto again;
3046	ext4_journal_stop(handle);
3047
3048	return err;
3049}
3050
3051/*
3052 * called at mount time
3053 */
3054void ext4_ext_init(struct super_block *sb)
3055{
3056	/*
3057	 * possible initialization would be here
3058	 */
3059
3060	if (ext4_has_feature_extents(sb)) {
3061#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3062		printk(KERN_INFO "EXT4-fs: file extents enabled"
3063#ifdef AGGRESSIVE_TEST
3064		       ", aggressive tests"
3065#endif
3066#ifdef CHECK_BINSEARCH
3067		       ", check binsearch"
3068#endif
3069#ifdef EXTENTS_STATS
3070		       ", stats"
3071#endif
3072		       "\n");
3073#endif
3074#ifdef EXTENTS_STATS
3075		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3076		EXT4_SB(sb)->s_ext_min = 1 << 30;
3077		EXT4_SB(sb)->s_ext_max = 0;
3078#endif
3079	}
3080}
3081
3082/*
3083 * called at umount time
3084 */
3085void ext4_ext_release(struct super_block *sb)
3086{
3087	if (!ext4_has_feature_extents(sb))
3088		return;
3089
3090#ifdef EXTENTS_STATS
3091	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3092		struct ext4_sb_info *sbi = EXT4_SB(sb);
3093		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3094			sbi->s_ext_blocks, sbi->s_ext_extents,
3095			sbi->s_ext_blocks / sbi->s_ext_extents);
3096		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3097			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3098	}
3099#endif
3100}
3101
3102static void ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3103{
3104	ext4_lblk_t  ee_block;
3105	ext4_fsblk_t ee_pblock;
3106	unsigned int ee_len;
3107
3108	ee_block  = le32_to_cpu(ex->ee_block);
3109	ee_len    = ext4_ext_get_actual_len(ex);
3110	ee_pblock = ext4_ext_pblock(ex);
3111
3112	if (ee_len == 0)
3113		return;
3114
3115	ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3116			      EXTENT_STATUS_WRITTEN);
3117}
3118
3119/* FIXME!! we need to try to merge to left or right after zero-out  */
3120static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3121{
3122	ext4_fsblk_t ee_pblock;
3123	unsigned int ee_len;
3124
3125	ee_len    = ext4_ext_get_actual_len(ex);
3126	ee_pblock = ext4_ext_pblock(ex);
3127	return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3128				  ee_len);
3129}
3130
3131/*
3132 * ext4_split_extent_at() splits an extent at given block.
3133 *
3134 * @handle: the journal handle
3135 * @inode: the file inode
3136 * @path: the path to the extent
3137 * @split: the logical block where the extent is splitted.
3138 * @split_flags: indicates if the extent could be zeroout if split fails, and
3139 *		 the states(init or unwritten) of new extents.
3140 * @flags: flags used to insert new extent to extent tree.
3141 *
3142 *
3143 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3144 * of which are determined by split_flag.
3145 *
3146 * There are two cases:
3147 *  a> the extent are splitted into two extent.
3148 *  b> split is not needed, and just mark the extent.
3149 *
3150 * return 0 on success.
3151 */
3152static int ext4_split_extent_at(handle_t *handle,
3153			     struct inode *inode,
3154			     struct ext4_ext_path **ppath,
3155			     ext4_lblk_t split,
3156			     int split_flag,
3157			     int flags)
3158{
3159	struct ext4_ext_path *path = *ppath;
3160	ext4_fsblk_t newblock;
3161	ext4_lblk_t ee_block;
3162	struct ext4_extent *ex, newex, orig_ex, zero_ex;
3163	struct ext4_extent *ex2 = NULL;
3164	unsigned int ee_len, depth;
3165	int err = 0;
3166
3167	BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3168	       (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3169
3170	ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
 
3171
3172	ext4_ext_show_leaf(inode, path);
3173
3174	depth = ext_depth(inode);
3175	ex = path[depth].p_ext;
3176	ee_block = le32_to_cpu(ex->ee_block);
3177	ee_len = ext4_ext_get_actual_len(ex);
3178	newblock = split - ee_block + ext4_ext_pblock(ex);
3179
3180	BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3181	BUG_ON(!ext4_ext_is_unwritten(ex) &&
3182	       split_flag & (EXT4_EXT_MAY_ZEROOUT |
3183			     EXT4_EXT_MARK_UNWRIT1 |
3184			     EXT4_EXT_MARK_UNWRIT2));
3185
3186	err = ext4_ext_get_access(handle, inode, path + depth);
3187	if (err)
3188		goto out;
3189
3190	if (split == ee_block) {
3191		/*
3192		 * case b: block @split is the block that the extent begins with
3193		 * then we just change the state of the extent, and splitting
3194		 * is not needed.
3195		 */
3196		if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3197			ext4_ext_mark_unwritten(ex);
3198		else
3199			ext4_ext_mark_initialized(ex);
3200
3201		if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3202			ext4_ext_try_to_merge(handle, inode, path, ex);
3203
3204		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3205		goto out;
3206	}
3207
3208	/* case a */
3209	memcpy(&orig_ex, ex, sizeof(orig_ex));
3210	ex->ee_len = cpu_to_le16(split - ee_block);
3211	if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3212		ext4_ext_mark_unwritten(ex);
3213
3214	/*
3215	 * path may lead to new leaf, not to original leaf any more
3216	 * after ext4_ext_insert_extent() returns,
3217	 */
3218	err = ext4_ext_dirty(handle, inode, path + depth);
3219	if (err)
3220		goto fix_extent_len;
3221
3222	ex2 = &newex;
3223	ex2->ee_block = cpu_to_le32(split);
3224	ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3225	ext4_ext_store_pblock(ex2, newblock);
3226	if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3227		ext4_ext_mark_unwritten(ex2);
3228
3229	err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3230	if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
3231		goto out;
3232
3233	if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3234		if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3235			if (split_flag & EXT4_EXT_DATA_VALID1) {
3236				err = ext4_ext_zeroout(inode, ex2);
3237				zero_ex.ee_block = ex2->ee_block;
3238				zero_ex.ee_len = cpu_to_le16(
3239						ext4_ext_get_actual_len(ex2));
3240				ext4_ext_store_pblock(&zero_ex,
3241						      ext4_ext_pblock(ex2));
3242			} else {
3243				err = ext4_ext_zeroout(inode, ex);
3244				zero_ex.ee_block = ex->ee_block;
3245				zero_ex.ee_len = cpu_to_le16(
3246						ext4_ext_get_actual_len(ex));
3247				ext4_ext_store_pblock(&zero_ex,
3248						      ext4_ext_pblock(ex));
3249			}
3250		} else {
3251			err = ext4_ext_zeroout(inode, &orig_ex);
3252			zero_ex.ee_block = orig_ex.ee_block;
3253			zero_ex.ee_len = cpu_to_le16(
3254						ext4_ext_get_actual_len(&orig_ex));
3255			ext4_ext_store_pblock(&zero_ex,
3256					      ext4_ext_pblock(&orig_ex));
3257		}
3258
3259		if (!err) {
3260			/* update the extent length and mark as initialized */
3261			ex->ee_len = cpu_to_le16(ee_len);
3262			ext4_ext_try_to_merge(handle, inode, path, ex);
3263			err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3264			if (!err)
3265				/* update extent status tree */
3266				ext4_zeroout_es(inode, &zero_ex);
3267			/* If we failed at this point, we don't know in which
3268			 * state the extent tree exactly is so don't try to fix
3269			 * length of the original extent as it may do even more
3270			 * damage.
3271			 */
3272			goto out;
3273		}
3274	}
 
 
 
3275
3276fix_extent_len:
3277	ex->ee_len = orig_ex.ee_len;
3278	/*
3279	 * Ignore ext4_ext_dirty return value since we are already in error path
3280	 * and err is a non-zero error code.
3281	 */
3282	ext4_ext_dirty(handle, inode, path + path->p_depth);
3283	return err;
3284out:
3285	ext4_ext_show_leaf(inode, path);
3286	return err;
3287}
3288
3289/*
3290 * ext4_split_extents() splits an extent and mark extent which is covered
3291 * by @map as split_flags indicates
3292 *
3293 * It may result in splitting the extent into multiple extents (up to three)
3294 * There are three possibilities:
3295 *   a> There is no split required
3296 *   b> Splits in two extents: Split is happening at either end of the extent
3297 *   c> Splits in three extents: Somone is splitting in middle of the extent
3298 *
3299 */
3300static int ext4_split_extent(handle_t *handle,
3301			      struct inode *inode,
3302			      struct ext4_ext_path **ppath,
3303			      struct ext4_map_blocks *map,
3304			      int split_flag,
3305			      int flags)
3306{
3307	struct ext4_ext_path *path = *ppath;
3308	ext4_lblk_t ee_block;
3309	struct ext4_extent *ex;
3310	unsigned int ee_len, depth;
3311	int err = 0;
3312	int unwritten;
3313	int split_flag1, flags1;
3314	int allocated = map->m_len;
3315
3316	depth = ext_depth(inode);
3317	ex = path[depth].p_ext;
3318	ee_block = le32_to_cpu(ex->ee_block);
3319	ee_len = ext4_ext_get_actual_len(ex);
3320	unwritten = ext4_ext_is_unwritten(ex);
3321
3322	if (map->m_lblk + map->m_len < ee_block + ee_len) {
3323		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3324		flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3325		if (unwritten)
3326			split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3327				       EXT4_EXT_MARK_UNWRIT2;
3328		if (split_flag & EXT4_EXT_DATA_VALID2)
3329			split_flag1 |= EXT4_EXT_DATA_VALID1;
3330		err = ext4_split_extent_at(handle, inode, ppath,
3331				map->m_lblk + map->m_len, split_flag1, flags1);
3332		if (err)
3333			goto out;
3334	} else {
3335		allocated = ee_len - (map->m_lblk - ee_block);
3336	}
3337	/*
3338	 * Update path is required because previous ext4_split_extent_at() may
3339	 * result in split of original leaf or extent zeroout.
3340	 */
3341	path = ext4_find_extent(inode, map->m_lblk, ppath, flags);
3342	if (IS_ERR(path))
3343		return PTR_ERR(path);
3344	depth = ext_depth(inode);
3345	ex = path[depth].p_ext;
3346	if (!ex) {
3347		EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3348				 (unsigned long) map->m_lblk);
3349		return -EFSCORRUPTED;
3350	}
3351	unwritten = ext4_ext_is_unwritten(ex);
 
3352
3353	if (map->m_lblk >= ee_block) {
3354		split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3355		if (unwritten) {
3356			split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3357			split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3358						     EXT4_EXT_MARK_UNWRIT2);
3359		}
3360		err = ext4_split_extent_at(handle, inode, ppath,
3361				map->m_lblk, split_flag1, flags);
3362		if (err)
3363			goto out;
3364	}
3365
3366	ext4_ext_show_leaf(inode, path);
3367out:
3368	return err ? err : allocated;
3369}
3370
3371/*
3372 * This function is called by ext4_ext_map_blocks() if someone tries to write
3373 * to an unwritten extent. It may result in splitting the unwritten
3374 * extent into multiple extents (up to three - one initialized and two
3375 * unwritten).
3376 * There are three possibilities:
3377 *   a> There is no split required: Entire extent should be initialized
3378 *   b> Splits in two extents: Write is happening at either end of the extent
3379 *   c> Splits in three extents: Somone is writing in middle of the extent
3380 *
3381 * Pre-conditions:
3382 *  - The extent pointed to by 'path' is unwritten.
3383 *  - The extent pointed to by 'path' contains a superset
3384 *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3385 *
3386 * Post-conditions on success:
3387 *  - the returned value is the number of blocks beyond map->l_lblk
3388 *    that are allocated and initialized.
3389 *    It is guaranteed to be >= map->m_len.
3390 */
3391static int ext4_ext_convert_to_initialized(handle_t *handle,
3392					   struct inode *inode,
3393					   struct ext4_map_blocks *map,
3394					   struct ext4_ext_path **ppath,
3395					   int flags)
3396{
3397	struct ext4_ext_path *path = *ppath;
3398	struct ext4_sb_info *sbi;
3399	struct ext4_extent_header *eh;
3400	struct ext4_map_blocks split_map;
3401	struct ext4_extent zero_ex1, zero_ex2;
3402	struct ext4_extent *ex, *abut_ex;
3403	ext4_lblk_t ee_block, eof_block;
3404	unsigned int ee_len, depth, map_len = map->m_len;
3405	int allocated = 0, max_zeroout = 0;
3406	int err = 0;
3407	int split_flag = EXT4_EXT_DATA_VALID2;
3408
3409	ext_debug(inode, "logical block %llu, max_blocks %u\n",
3410		  (unsigned long long)map->m_lblk, map_len);
 
3411
3412	sbi = EXT4_SB(inode->i_sb);
3413	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3414			>> inode->i_sb->s_blocksize_bits;
3415	if (eof_block < map->m_lblk + map_len)
3416		eof_block = map->m_lblk + map_len;
3417
3418	depth = ext_depth(inode);
3419	eh = path[depth].p_hdr;
3420	ex = path[depth].p_ext;
3421	ee_block = le32_to_cpu(ex->ee_block);
3422	ee_len = ext4_ext_get_actual_len(ex);
3423	zero_ex1.ee_len = 0;
3424	zero_ex2.ee_len = 0;
3425
3426	trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3427
3428	/* Pre-conditions */
3429	BUG_ON(!ext4_ext_is_unwritten(ex));
3430	BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3431
3432	/*
3433	 * Attempt to transfer newly initialized blocks from the currently
3434	 * unwritten extent to its neighbor. This is much cheaper
3435	 * than an insertion followed by a merge as those involve costly
3436	 * memmove() calls. Transferring to the left is the common case in
3437	 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3438	 * followed by append writes.
3439	 *
3440	 * Limitations of the current logic:
3441	 *  - L1: we do not deal with writes covering the whole extent.
3442	 *    This would require removing the extent if the transfer
3443	 *    is possible.
3444	 *  - L2: we only attempt to merge with an extent stored in the
3445	 *    same extent tree node.
3446	 */
3447	if ((map->m_lblk == ee_block) &&
3448		/* See if we can merge left */
3449		(map_len < ee_len) &&		/*L1*/
3450		(ex > EXT_FIRST_EXTENT(eh))) {	/*L2*/
3451		ext4_lblk_t prev_lblk;
3452		ext4_fsblk_t prev_pblk, ee_pblk;
3453		unsigned int prev_len;
3454
3455		abut_ex = ex - 1;
3456		prev_lblk = le32_to_cpu(abut_ex->ee_block);
3457		prev_len = ext4_ext_get_actual_len(abut_ex);
3458		prev_pblk = ext4_ext_pblock(abut_ex);
3459		ee_pblk = ext4_ext_pblock(ex);
3460
3461		/*
3462		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3463		 * upon those conditions:
3464		 * - C1: abut_ex is initialized,
3465		 * - C2: abut_ex is logically abutting ex,
3466		 * - C3: abut_ex is physically abutting ex,
3467		 * - C4: abut_ex can receive the additional blocks without
3468		 *   overflowing the (initialized) length limit.
3469		 */
3470		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
3471			((prev_lblk + prev_len) == ee_block) &&		/*C2*/
3472			((prev_pblk + prev_len) == ee_pblk) &&		/*C3*/
3473			(prev_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
3474			err = ext4_ext_get_access(handle, inode, path + depth);
3475			if (err)
3476				goto out;
3477
3478			trace_ext4_ext_convert_to_initialized_fastpath(inode,
3479				map, ex, abut_ex);
3480
3481			/* Shift the start of ex by 'map_len' blocks */
3482			ex->ee_block = cpu_to_le32(ee_block + map_len);
3483			ext4_ext_store_pblock(ex, ee_pblk + map_len);
3484			ex->ee_len = cpu_to_le16(ee_len - map_len);
3485			ext4_ext_mark_unwritten(ex); /* Restore the flag */
3486
3487			/* Extend abut_ex by 'map_len' blocks */
3488			abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3489
3490			/* Result: number of initialized blocks past m_lblk */
3491			allocated = map_len;
3492		}
3493	} else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3494		   (map_len < ee_len) &&	/*L1*/
3495		   ex < EXT_LAST_EXTENT(eh)) {	/*L2*/
3496		/* See if we can merge right */
3497		ext4_lblk_t next_lblk;
3498		ext4_fsblk_t next_pblk, ee_pblk;
3499		unsigned int next_len;
3500
3501		abut_ex = ex + 1;
3502		next_lblk = le32_to_cpu(abut_ex->ee_block);
3503		next_len = ext4_ext_get_actual_len(abut_ex);
3504		next_pblk = ext4_ext_pblock(abut_ex);
3505		ee_pblk = ext4_ext_pblock(ex);
3506
3507		/*
3508		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3509		 * upon those conditions:
3510		 * - C1: abut_ex is initialized,
3511		 * - C2: abut_ex is logically abutting ex,
3512		 * - C3: abut_ex is physically abutting ex,
3513		 * - C4: abut_ex can receive the additional blocks without
3514		 *   overflowing the (initialized) length limit.
3515		 */
3516		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
3517		    ((map->m_lblk + map_len) == next_lblk) &&		/*C2*/
3518		    ((ee_pblk + ee_len) == next_pblk) &&		/*C3*/
3519		    (next_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
3520			err = ext4_ext_get_access(handle, inode, path + depth);
3521			if (err)
3522				goto out;
3523
3524			trace_ext4_ext_convert_to_initialized_fastpath(inode,
3525				map, ex, abut_ex);
3526
3527			/* Shift the start of abut_ex by 'map_len' blocks */
3528			abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3529			ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3530			ex->ee_len = cpu_to_le16(ee_len - map_len);
3531			ext4_ext_mark_unwritten(ex); /* Restore the flag */
3532
3533			/* Extend abut_ex by 'map_len' blocks */
3534			abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3535
3536			/* Result: number of initialized blocks past m_lblk */
3537			allocated = map_len;
3538		}
3539	}
3540	if (allocated) {
3541		/* Mark the block containing both extents as dirty */
3542		err = ext4_ext_dirty(handle, inode, path + depth);
3543
3544		/* Update path to point to the right extent */
3545		path[depth].p_ext = abut_ex;
3546		goto out;
3547	} else
3548		allocated = ee_len - (map->m_lblk - ee_block);
3549
3550	WARN_ON(map->m_lblk < ee_block);
3551	/*
3552	 * It is safe to convert extent to initialized via explicit
3553	 * zeroout only if extent is fully inside i_size or new_size.
3554	 */
3555	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3556
3557	if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3558		max_zeroout = sbi->s_extent_max_zeroout_kb >>
3559			(inode->i_sb->s_blocksize_bits - 10);
3560
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3561	/*
3562	 * five cases:
3563	 * 1. split the extent into three extents.
3564	 * 2. split the extent into two extents, zeroout the head of the first
3565	 *    extent.
3566	 * 3. split the extent into two extents, zeroout the tail of the second
3567	 *    extent.
3568	 * 4. split the extent into two extents with out zeroout.
3569	 * 5. no splitting needed, just possibly zeroout the head and / or the
3570	 *    tail of the extent.
3571	 */
3572	split_map.m_lblk = map->m_lblk;
3573	split_map.m_len = map->m_len;
3574
3575	if (max_zeroout && (allocated > split_map.m_len)) {
3576		if (allocated <= max_zeroout) {
3577			/* case 3 or 5 */
3578			zero_ex1.ee_block =
3579				 cpu_to_le32(split_map.m_lblk +
3580					     split_map.m_len);
3581			zero_ex1.ee_len =
3582				cpu_to_le16(allocated - split_map.m_len);
3583			ext4_ext_store_pblock(&zero_ex1,
3584				ext4_ext_pblock(ex) + split_map.m_lblk +
3585				split_map.m_len - ee_block);
3586			err = ext4_ext_zeroout(inode, &zero_ex1);
3587			if (err)
3588				goto fallback;
 
3589			split_map.m_len = allocated;
3590		}
3591		if (split_map.m_lblk - ee_block + split_map.m_len <
3592								max_zeroout) {
3593			/* case 2 or 5 */
3594			if (split_map.m_lblk != ee_block) {
3595				zero_ex2.ee_block = ex->ee_block;
3596				zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3597							ee_block);
3598				ext4_ext_store_pblock(&zero_ex2,
3599						      ext4_ext_pblock(ex));
3600				err = ext4_ext_zeroout(inode, &zero_ex2);
3601				if (err)
3602					goto fallback;
3603			}
3604
3605			split_map.m_len += split_map.m_lblk - ee_block;
3606			split_map.m_lblk = ee_block;
 
3607			allocated = map->m_len;
3608		}
3609	}
3610
3611fallback:
3612	err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3613				flags);
3614	if (err > 0)
3615		err = 0;
3616out:
3617	/* If we have gotten a failure, don't zero out status tree */
3618	if (!err) {
3619		ext4_zeroout_es(inode, &zero_ex1);
3620		ext4_zeroout_es(inode, &zero_ex2);
3621	}
3622	return err ? err : allocated;
3623}
3624
3625/*
3626 * This function is called by ext4_ext_map_blocks() from
3627 * ext4_get_blocks_dio_write() when DIO to write
3628 * to an unwritten extent.
3629 *
3630 * Writing to an unwritten extent may result in splitting the unwritten
3631 * extent into multiple initialized/unwritten extents (up to three)
3632 * There are three possibilities:
3633 *   a> There is no split required: Entire extent should be unwritten
3634 *   b> Splits in two extents: Write is happening at either end of the extent
3635 *   c> Splits in three extents: Somone is writing in middle of the extent
3636 *
3637 * This works the same way in the case of initialized -> unwritten conversion.
3638 *
3639 * One of more index blocks maybe needed if the extent tree grow after
3640 * the unwritten extent split. To prevent ENOSPC occur at the IO
3641 * complete, we need to split the unwritten extent before DIO submit
3642 * the IO. The unwritten extent called at this time will be split
3643 * into three unwritten extent(at most). After IO complete, the part
3644 * being filled will be convert to initialized by the end_io callback function
3645 * via ext4_convert_unwritten_extents().
3646 *
3647 * Returns the size of unwritten extent to be written on success.
3648 */
3649static int ext4_split_convert_extents(handle_t *handle,
3650					struct inode *inode,
3651					struct ext4_map_blocks *map,
3652					struct ext4_ext_path **ppath,
3653					int flags)
3654{
3655	struct ext4_ext_path *path = *ppath;
3656	ext4_lblk_t eof_block;
3657	ext4_lblk_t ee_block;
3658	struct ext4_extent *ex;
3659	unsigned int ee_len;
3660	int split_flag = 0, depth;
3661
3662	ext_debug(inode, "logical block %llu, max_blocks %u\n",
 
3663		  (unsigned long long)map->m_lblk, map->m_len);
3664
3665	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3666			>> inode->i_sb->s_blocksize_bits;
3667	if (eof_block < map->m_lblk + map->m_len)
3668		eof_block = map->m_lblk + map->m_len;
3669	/*
3670	 * It is safe to convert extent to initialized via explicit
3671	 * zeroout only if extent is fully inside i_size or new_size.
3672	 */
3673	depth = ext_depth(inode);
3674	ex = path[depth].p_ext;
3675	ee_block = le32_to_cpu(ex->ee_block);
3676	ee_len = ext4_ext_get_actual_len(ex);
3677
3678	/* Convert to unwritten */
3679	if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3680		split_flag |= EXT4_EXT_DATA_VALID1;
3681	/* Convert to initialized */
3682	} else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3683		split_flag |= ee_block + ee_len <= eof_block ?
3684			      EXT4_EXT_MAY_ZEROOUT : 0;
3685		split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3686	}
3687	flags |= EXT4_GET_BLOCKS_PRE_IO;
3688	return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3689}
3690
3691static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3692						struct inode *inode,
3693						struct ext4_map_blocks *map,
3694						struct ext4_ext_path **ppath)
3695{
3696	struct ext4_ext_path *path = *ppath;
3697	struct ext4_extent *ex;
3698	ext4_lblk_t ee_block;
3699	unsigned int ee_len;
3700	int depth;
3701	int err = 0;
3702
3703	depth = ext_depth(inode);
3704	ex = path[depth].p_ext;
3705	ee_block = le32_to_cpu(ex->ee_block);
3706	ee_len = ext4_ext_get_actual_len(ex);
3707
3708	ext_debug(inode, "logical block %llu, max_blocks %u\n",
 
3709		  (unsigned long long)ee_block, ee_len);
3710
3711	/* If extent is larger than requested it is a clear sign that we still
3712	 * have some extent state machine issues left. So extent_split is still
3713	 * required.
3714	 * TODO: Once all related issues will be fixed this situation should be
3715	 * illegal.
3716	 */
3717	if (ee_block != map->m_lblk || ee_len > map->m_len) {
3718#ifdef CONFIG_EXT4_DEBUG
3719		ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3720			     " len %u; IO logical block %llu, len %u",
3721			     inode->i_ino, (unsigned long long)ee_block, ee_len,
3722			     (unsigned long long)map->m_lblk, map->m_len);
3723#endif
3724		err = ext4_split_convert_extents(handle, inode, map, ppath,
3725						 EXT4_GET_BLOCKS_CONVERT);
3726		if (err < 0)
3727			return err;
3728		path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3729		if (IS_ERR(path))
3730			return PTR_ERR(path);
3731		depth = ext_depth(inode);
3732		ex = path[depth].p_ext;
3733	}
3734
3735	err = ext4_ext_get_access(handle, inode, path + depth);
3736	if (err)
3737		goto out;
3738	/* first mark the extent as initialized */
3739	ext4_ext_mark_initialized(ex);
3740
3741	/* note: ext4_ext_correct_indexes() isn't needed here because
3742	 * borders are not changed
3743	 */
3744	ext4_ext_try_to_merge(handle, inode, path, ex);
3745
3746	/* Mark modified extent as dirty */
3747	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3748out:
3749	ext4_ext_show_leaf(inode, path);
3750	return err;
3751}
3752
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3753static int
3754convert_initialized_extent(handle_t *handle, struct inode *inode,
3755			   struct ext4_map_blocks *map,
3756			   struct ext4_ext_path **ppath,
3757			   unsigned int *allocated)
3758{
3759	struct ext4_ext_path *path = *ppath;
3760	struct ext4_extent *ex;
3761	ext4_lblk_t ee_block;
3762	unsigned int ee_len;
3763	int depth;
3764	int err = 0;
3765
3766	/*
3767	 * Make sure that the extent is no bigger than we support with
3768	 * unwritten extent
3769	 */
3770	if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3771		map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3772
3773	depth = ext_depth(inode);
3774	ex = path[depth].p_ext;
3775	ee_block = le32_to_cpu(ex->ee_block);
3776	ee_len = ext4_ext_get_actual_len(ex);
3777
3778	ext_debug(inode, "logical block %llu, max_blocks %u\n",
 
3779		  (unsigned long long)ee_block, ee_len);
3780
3781	if (ee_block != map->m_lblk || ee_len > map->m_len) {
3782		err = ext4_split_convert_extents(handle, inode, map, ppath,
3783				EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3784		if (err < 0)
3785			return err;
3786		path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3787		if (IS_ERR(path))
3788			return PTR_ERR(path);
3789		depth = ext_depth(inode);
3790		ex = path[depth].p_ext;
3791		if (!ex) {
3792			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3793					 (unsigned long) map->m_lblk);
3794			return -EFSCORRUPTED;
3795		}
3796	}
3797
3798	err = ext4_ext_get_access(handle, inode, path + depth);
3799	if (err)
3800		return err;
3801	/* first mark the extent as unwritten */
3802	ext4_ext_mark_unwritten(ex);
3803
3804	/* note: ext4_ext_correct_indexes() isn't needed here because
3805	 * borders are not changed
3806	 */
3807	ext4_ext_try_to_merge(handle, inode, path, ex);
3808
3809	/* Mark modified extent as dirty */
3810	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3811	if (err)
3812		return err;
3813	ext4_ext_show_leaf(inode, path);
3814
3815	ext4_update_inode_fsync_trans(handle, inode, 1);
3816
 
 
3817	map->m_flags |= EXT4_MAP_UNWRITTEN;
3818	if (*allocated > map->m_len)
3819		*allocated = map->m_len;
3820	map->m_len = *allocated;
3821	return 0;
3822}
3823
3824static int
3825ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3826			struct ext4_map_blocks *map,
3827			struct ext4_ext_path **ppath, int flags,
3828			unsigned int allocated, ext4_fsblk_t newblock)
3829{
3830	struct ext4_ext_path __maybe_unused *path = *ppath;
3831	int ret = 0;
3832	int err = 0;
3833
3834	ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3835		  (unsigned long long)map->m_lblk, map->m_len, flags,
3836		  allocated);
 
3837	ext4_ext_show_leaf(inode, path);
3838
3839	/*
3840	 * When writing into unwritten space, we should not fail to
3841	 * allocate metadata blocks for the new extent block if needed.
3842	 */
3843	flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3844
3845	trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3846						    allocated, newblock);
3847
3848	/* get_block() before submitting IO, split the extent */
3849	if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3850		ret = ext4_split_convert_extents(handle, inode, map, ppath,
3851					 flags | EXT4_GET_BLOCKS_CONVERT);
3852		if (ret < 0) {
3853			err = ret;
3854			goto out2;
3855		}
3856		/*
3857		 * shouldn't get a 0 return when splitting an extent unless
3858		 * m_len is 0 (bug) or extent has been corrupted
3859		 */
3860		if (unlikely(ret == 0)) {
3861			EXT4_ERROR_INODE(inode,
3862					 "unexpected ret == 0, m_len = %u",
3863					 map->m_len);
3864			err = -EFSCORRUPTED;
3865			goto out2;
3866		}
3867		map->m_flags |= EXT4_MAP_UNWRITTEN;
3868		goto out;
3869	}
3870	/* IO end_io complete, convert the filled extent to written */
3871	if (flags & EXT4_GET_BLOCKS_CONVERT) {
3872		err = ext4_convert_unwritten_extents_endio(handle, inode, map,
 
 
 
 
 
 
 
 
3873							   ppath);
3874		if (err < 0)
3875			goto out2;
3876		ext4_update_inode_fsync_trans(handle, inode, 1);
3877		goto map_out;
 
 
 
 
 
 
 
 
3878	}
3879	/* buffered IO cases */
3880	/*
3881	 * repeat fallocate creation request
3882	 * we already have an unwritten extent
3883	 */
3884	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3885		map->m_flags |= EXT4_MAP_UNWRITTEN;
3886		goto map_out;
3887	}
3888
3889	/* buffered READ or buffered write_begin() lookup */
3890	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3891		/*
3892		 * We have blocks reserved already.  We
3893		 * return allocated blocks so that delalloc
3894		 * won't do block reservation for us.  But
3895		 * the buffer head will be unmapped so that
3896		 * a read from the block returns 0s.
3897		 */
3898		map->m_flags |= EXT4_MAP_UNWRITTEN;
3899		goto out1;
3900	}
3901
3902	/*
3903	 * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3904	 * For buffered writes, at writepage time, etc.  Convert a
3905	 * discovered unwritten extent to written.
3906	 */
3907	ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
3908	if (ret < 0) {
 
 
 
3909		err = ret;
3910		goto out2;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3911	}
3912	ext4_update_inode_fsync_trans(handle, inode, 1);
 
3913	/*
3914	 * shouldn't get a 0 return when converting an unwritten extent
3915	 * unless m_len is 0 (bug) or extent has been corrupted
3916	 */
3917	if (unlikely(ret == 0)) {
3918		EXT4_ERROR_INODE(inode, "unexpected ret == 0, m_len = %u",
3919				 map->m_len);
3920		err = -EFSCORRUPTED;
3921		goto out2;
 
 
 
 
 
 
3922	}
3923
3924out:
3925	allocated = ret;
3926	map->m_flags |= EXT4_MAP_NEW;
3927map_out:
3928	map->m_flags |= EXT4_MAP_MAPPED;
 
 
 
 
 
 
3929out1:
3930	map->m_pblk = newblock;
3931	if (allocated > map->m_len)
3932		allocated = map->m_len;
 
 
3933	map->m_len = allocated;
3934	ext4_ext_show_leaf(inode, path);
3935out2:
3936	return err ? err : allocated;
3937}
3938
3939/*
3940 * get_implied_cluster_alloc - check to see if the requested
3941 * allocation (in the map structure) overlaps with a cluster already
3942 * allocated in an extent.
3943 *	@sb	The filesystem superblock structure
3944 *	@map	The requested lblk->pblk mapping
3945 *	@ex	The extent structure which might contain an implied
3946 *			cluster allocation
3947 *
3948 * This function is called by ext4_ext_map_blocks() after we failed to
3949 * find blocks that were already in the inode's extent tree.  Hence,
3950 * we know that the beginning of the requested region cannot overlap
3951 * the extent from the inode's extent tree.  There are three cases we
3952 * want to catch.  The first is this case:
3953 *
3954 *		 |--- cluster # N--|
3955 *    |--- extent ---|	|---- requested region ---|
3956 *			|==========|
3957 *
3958 * The second case that we need to test for is this one:
3959 *
3960 *   |--------- cluster # N ----------------|
3961 *	   |--- requested region --|   |------- extent ----|
3962 *	   |=======================|
3963 *
3964 * The third case is when the requested region lies between two extents
3965 * within the same cluster:
3966 *          |------------- cluster # N-------------|
3967 * |----- ex -----|                  |---- ex_right ----|
3968 *                  |------ requested region ------|
3969 *                  |================|
3970 *
3971 * In each of the above cases, we need to set the map->m_pblk and
3972 * map->m_len so it corresponds to the return the extent labelled as
3973 * "|====|" from cluster #N, since it is already in use for data in
3974 * cluster EXT4_B2C(sbi, map->m_lblk).	We will then return 1 to
3975 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3976 * as a new "allocated" block region.  Otherwise, we will return 0 and
3977 * ext4_ext_map_blocks() will then allocate one or more new clusters
3978 * by calling ext4_mb_new_blocks().
3979 */
3980static int get_implied_cluster_alloc(struct super_block *sb,
3981				     struct ext4_map_blocks *map,
3982				     struct ext4_extent *ex,
3983				     struct ext4_ext_path *path)
3984{
3985	struct ext4_sb_info *sbi = EXT4_SB(sb);
3986	ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
3987	ext4_lblk_t ex_cluster_start, ex_cluster_end;
3988	ext4_lblk_t rr_cluster_start;
3989	ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3990	ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3991	unsigned short ee_len = ext4_ext_get_actual_len(ex);
3992
3993	/* The extent passed in that we are trying to match */
3994	ex_cluster_start = EXT4_B2C(sbi, ee_block);
3995	ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
3996
3997	/* The requested region passed into ext4_map_blocks() */
3998	rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
3999
4000	if ((rr_cluster_start == ex_cluster_end) ||
4001	    (rr_cluster_start == ex_cluster_start)) {
4002		if (rr_cluster_start == ex_cluster_end)
4003			ee_start += ee_len - 1;
4004		map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4005		map->m_len = min(map->m_len,
4006				 (unsigned) sbi->s_cluster_ratio - c_offset);
4007		/*
4008		 * Check for and handle this case:
4009		 *
4010		 *   |--------- cluster # N-------------|
4011		 *		       |------- extent ----|
4012		 *	   |--- requested region ---|
4013		 *	   |===========|
4014		 */
4015
4016		if (map->m_lblk < ee_block)
4017			map->m_len = min(map->m_len, ee_block - map->m_lblk);
4018
4019		/*
4020		 * Check for the case where there is already another allocated
4021		 * block to the right of 'ex' but before the end of the cluster.
4022		 *
4023		 *          |------------- cluster # N-------------|
4024		 * |----- ex -----|                  |---- ex_right ----|
4025		 *                  |------ requested region ------|
4026		 *                  |================|
4027		 */
4028		if (map->m_lblk > ee_block) {
4029			ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4030			map->m_len = min(map->m_len, next - map->m_lblk);
4031		}
4032
4033		trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4034		return 1;
4035	}
4036
4037	trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4038	return 0;
4039}
4040
4041/*
4042 * Determine hole length around the given logical block, first try to
4043 * locate and expand the hole from the given @path, and then adjust it
4044 * if it's partially or completely converted to delayed extents, insert
4045 * it into the extent cache tree if it's indeed a hole, finally return
4046 * the length of the determined extent.
4047 */
4048static ext4_lblk_t ext4_ext_determine_insert_hole(struct inode *inode,
4049						  struct ext4_ext_path *path,
4050						  ext4_lblk_t lblk)
4051{
4052	ext4_lblk_t hole_start, len;
4053	struct extent_status es;
4054
4055	hole_start = lblk;
4056	len = ext4_ext_find_hole(inode, path, &hole_start);
4057again:
4058	ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
4059				  hole_start + len - 1, &es);
4060	if (!es.es_len)
4061		goto insert_hole;
4062
4063	/*
4064	 * There's a delalloc extent in the hole, handle it if the delalloc
4065	 * extent is in front of, behind and straddle the queried range.
4066	 */
4067	if (lblk >= es.es_lblk + es.es_len) {
4068		/*
4069		 * The delalloc extent is in front of the queried range,
4070		 * find again from the queried start block.
4071		 */
4072		len -= lblk - hole_start;
4073		hole_start = lblk;
4074		goto again;
4075	} else if (in_range(lblk, es.es_lblk, es.es_len)) {
4076		/*
4077		 * The delalloc extent containing lblk, it must have been
4078		 * added after ext4_map_blocks() checked the extent status
4079		 * tree so we are not holding i_rwsem and delalloc info is
4080		 * only stabilized by i_data_sem we are going to release
4081		 * soon. Don't modify the extent status tree and report
4082		 * extent as a hole, just adjust the length to the delalloc
4083		 * extent's after lblk.
4084		 */
4085		len = es.es_lblk + es.es_len - lblk;
4086		return len;
4087	} else {
4088		/*
4089		 * The delalloc extent is partially or completely behind
4090		 * the queried range, update hole length until the
4091		 * beginning of the delalloc extent.
4092		 */
4093		len = min(es.es_lblk - hole_start, len);
4094	}
4095
4096insert_hole:
4097	/* Put just found gap into cache to speed up subsequent requests */
4098	ext_debug(inode, " -> %u:%u\n", hole_start, len);
4099	ext4_es_insert_extent(inode, hole_start, len, ~0, EXTENT_STATUS_HOLE);
4100
4101	/* Update hole_len to reflect hole size after lblk */
4102	if (hole_start != lblk)
4103		len -= lblk - hole_start;
4104
4105	return len;
4106}
4107
4108/*
4109 * Block allocation/map/preallocation routine for extents based files
4110 *
4111 *
4112 * Need to be called with
4113 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4114 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4115 *
4116 * return > 0, number of blocks already mapped/allocated
4117 *          if create == 0 and these are pre-allocated blocks
4118 *          	buffer head is unmapped
4119 *          otherwise blocks are mapped
4120 *
4121 * return = 0, if plain look up failed (blocks have not been allocated)
4122 *          buffer head is unmapped
4123 *
4124 * return < 0, error case.
4125 */
4126int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4127			struct ext4_map_blocks *map, int flags)
4128{
4129	struct ext4_ext_path *path = NULL;
4130	struct ext4_extent newex, *ex, ex2;
4131	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4132	ext4_fsblk_t newblock = 0, pblk;
4133	int err = 0, depth, ret;
4134	unsigned int allocated = 0, offset = 0;
4135	unsigned int allocated_clusters = 0;
4136	struct ext4_allocation_request ar;
4137	ext4_lblk_t cluster_offset;
 
4138
4139	ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
 
4140	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4141
4142	/* find extent for this block */
4143	path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4144	if (IS_ERR(path)) {
4145		err = PTR_ERR(path);
4146		path = NULL;
4147		goto out;
4148	}
4149
4150	depth = ext_depth(inode);
4151
4152	/*
4153	 * consistent leaf must not be empty;
4154	 * this situation is possible, though, _during_ tree modification;
4155	 * this is why assert can't be put in ext4_find_extent()
4156	 */
4157	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4158		EXT4_ERROR_INODE(inode, "bad extent address "
4159				 "lblock: %lu, depth: %d pblock %lld",
4160				 (unsigned long) map->m_lblk, depth,
4161				 path[depth].p_block);
4162		err = -EFSCORRUPTED;
4163		goto out;
4164	}
4165
4166	ex = path[depth].p_ext;
4167	if (ex) {
4168		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4169		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4170		unsigned short ee_len;
4171
4172
4173		/*
4174		 * unwritten extents are treated as holes, except that
4175		 * we split out initialized portions during a write.
4176		 */
4177		ee_len = ext4_ext_get_actual_len(ex);
4178
4179		trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4180
4181		/* if found extent covers block, simply return it */
4182		if (in_range(map->m_lblk, ee_block, ee_len)) {
4183			newblock = map->m_lblk - ee_block + ee_start;
4184			/* number of remaining blocks in the extent */
4185			allocated = ee_len - (map->m_lblk - ee_block);
4186			ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4187				  map->m_lblk, ee_block, ee_len, newblock);
4188
4189			/*
4190			 * If the extent is initialized check whether the
4191			 * caller wants to convert it to unwritten.
4192			 */
4193			if ((!ext4_ext_is_unwritten(ex)) &&
4194			    (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4195				err = convert_initialized_extent(handle,
4196					inode, map, &path, &allocated);
4197				goto out;
4198			} else if (!ext4_ext_is_unwritten(ex)) {
4199				map->m_flags |= EXT4_MAP_MAPPED;
4200				map->m_pblk = newblock;
4201				if (allocated > map->m_len)
4202					allocated = map->m_len;
4203				map->m_len = allocated;
4204				ext4_ext_show_leaf(inode, path);
4205				goto out;
4206			}
4207
4208			ret = ext4_ext_handle_unwritten_extents(
4209				handle, inode, map, &path, flags,
4210				allocated, newblock);
4211			if (ret < 0)
4212				err = ret;
4213			else
4214				allocated = ret;
4215			goto out;
4216		}
4217	}
4218
4219	/*
4220	 * requested block isn't allocated yet;
4221	 * we couldn't try to create block if create flag is zero
4222	 */
4223	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4224		ext4_lblk_t len;
4225
4226		len = ext4_ext_determine_insert_hole(inode, path, map->m_lblk);
 
 
 
 
 
 
4227
 
 
 
4228		map->m_pblk = 0;
4229		map->m_len = min_t(unsigned int, map->m_len, len);
4230		goto out;
 
4231	}
4232
4233	/*
4234	 * Okay, we need to do block allocation.
4235	 */
4236	newex.ee_block = cpu_to_le32(map->m_lblk);
4237	cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4238
4239	/*
4240	 * If we are doing bigalloc, check to see if the extent returned
4241	 * by ext4_find_extent() implies a cluster we can use.
4242	 */
4243	if (cluster_offset && ex &&
4244	    get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4245		ar.len = allocated = map->m_len;
4246		newblock = map->m_pblk;
 
4247		goto got_allocated_blocks;
4248	}
4249
4250	/* find neighbour allocated blocks */
4251	ar.lleft = map->m_lblk;
4252	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4253	if (err)
4254		goto out;
4255	ar.lright = map->m_lblk;
 
4256	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4257	if (err < 0)
4258		goto out;
4259
4260	/* Check if the extent after searching to the right implies a
4261	 * cluster we can use. */
4262	if ((sbi->s_cluster_ratio > 1) && err &&
4263	    get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4264		ar.len = allocated = map->m_len;
4265		newblock = map->m_pblk;
 
4266		goto got_allocated_blocks;
4267	}
4268
4269	/*
4270	 * See if request is beyond maximum number of blocks we can have in
4271	 * a single extent. For an initialized extent this limit is
4272	 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4273	 * EXT_UNWRITTEN_MAX_LEN.
4274	 */
4275	if (map->m_len > EXT_INIT_MAX_LEN &&
4276	    !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4277		map->m_len = EXT_INIT_MAX_LEN;
4278	else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4279		 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4280		map->m_len = EXT_UNWRITTEN_MAX_LEN;
4281
4282	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4283	newex.ee_len = cpu_to_le16(map->m_len);
4284	err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4285	if (err)
4286		allocated = ext4_ext_get_actual_len(&newex);
4287	else
4288		allocated = map->m_len;
4289
4290	/* allocate new block */
4291	ar.inode = inode;
4292	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4293	ar.logical = map->m_lblk;
4294	/*
4295	 * We calculate the offset from the beginning of the cluster
4296	 * for the logical block number, since when we allocate a
4297	 * physical cluster, the physical block should start at the
4298	 * same offset from the beginning of the cluster.  This is
4299	 * needed so that future calls to get_implied_cluster_alloc()
4300	 * work correctly.
4301	 */
4302	offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4303	ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4304	ar.goal -= offset;
4305	ar.logical -= offset;
4306	if (S_ISREG(inode->i_mode))
4307		ar.flags = EXT4_MB_HINT_DATA;
4308	else
4309		/* disable in-core preallocation for non-regular files */
4310		ar.flags = 0;
4311	if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4312		ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4313	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4314		ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4315	if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4316		ar.flags |= EXT4_MB_USE_RESERVED;
4317	newblock = ext4_mb_new_blocks(handle, &ar, &err);
4318	if (!newblock)
4319		goto out;
 
 
 
4320	allocated_clusters = ar.len;
4321	ar.len = EXT4_C2B(sbi, ar.len) - offset;
4322	ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4323		  ar.goal, newblock, ar.len, allocated);
4324	if (ar.len > allocated)
4325		ar.len = allocated;
4326
4327got_allocated_blocks:
4328	/* try to insert new extent into found leaf and return */
4329	pblk = newblock + offset;
4330	ext4_ext_store_pblock(&newex, pblk);
4331	newex.ee_len = cpu_to_le16(ar.len);
4332	/* Mark unwritten */
4333	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4334		ext4_ext_mark_unwritten(&newex);
4335		map->m_flags |= EXT4_MAP_UNWRITTEN;
4336	}
4337
4338	err = ext4_ext_insert_extent(handle, inode, &path, &newex, flags);
4339	if (err) {
4340		if (allocated_clusters) {
4341			int fb_flags = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4342
4343			/*
4344			 * free data blocks we just allocated.
4345			 * not a good idea to call discard here directly,
4346			 * but otherwise we'd need to call it every free().
4347			 */
4348			ext4_discard_preallocations(inode);
4349			if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4350				fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4351			ext4_free_blocks(handle, inode, NULL, newblock,
4352					 EXT4_C2B(sbi, allocated_clusters),
4353					 fb_flags);
4354		}
4355		goto out;
4356	}
4357
4358	/*
4359	 * Reduce the reserved cluster count to reflect successful deferred
4360	 * allocation of delayed allocated clusters or direct allocation of
4361	 * clusters discovered to be delayed allocated.  Once allocated, a
4362	 * cluster is not included in the reserved count.
4363	 */
4364	if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
4365		if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4366			/*
4367			 * When allocating delayed allocated clusters, simply
4368			 * reduce the reserved cluster count and claim quota
 
 
 
4369			 */
4370			ext4_da_update_reserve_space(inode, allocated_clusters,
4371							1);
4372		} else {
4373			ext4_lblk_t lblk, len;
4374			unsigned int n;
4375
4376			/*
4377			 * When allocating non-delayed allocated clusters
4378			 * (from fallocate, filemap, DIO, or clusters
4379			 * allocated when delalloc has been disabled by
4380			 * ext4_nonda_switch), reduce the reserved cluster
4381			 * count by the number of allocated clusters that
4382			 * have previously been delayed allocated.  Quota
4383			 * has been claimed by ext4_mb_new_blocks() above,
4384			 * so release the quota reservations made for any
4385			 * previously delayed allocated clusters.
4386			 */
4387			lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4388			len = allocated_clusters << sbi->s_cluster_bits;
4389			n = ext4_es_delayed_clu(inode, lblk, len);
4390			if (n > 0)
4391				ext4_da_update_reserve_space(inode, (int) n, 0);
4392		}
4393	}
4394
4395	/*
4396	 * Cache the extent and update transaction to commit on fdatasync only
4397	 * when it is _not_ an unwritten extent.
4398	 */
4399	if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4400		ext4_update_inode_fsync_trans(handle, inode, 1);
4401	else
4402		ext4_update_inode_fsync_trans(handle, inode, 0);
4403
4404	map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4405	map->m_pblk = pblk;
4406	map->m_len = ar.len;
4407	allocated = map->m_len;
4408	ext4_ext_show_leaf(inode, path);
4409out:
4410	ext4_free_ext_path(path);
 
 
 
 
4411
4412	trace_ext4_ext_map_blocks_exit(inode, flags, map,
4413				       err ? err : allocated);
4414	return err ? err : allocated;
4415}
4416
4417int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4418{
4419	struct super_block *sb = inode->i_sb;
4420	ext4_lblk_t last_block;
4421	int err = 0;
4422
4423	/*
4424	 * TODO: optimization is possible here.
4425	 * Probably we need not scan at all,
4426	 * because page truncation is enough.
4427	 */
4428
4429	/* we have to know where to truncate from in crash case */
4430	EXT4_I(inode)->i_disksize = inode->i_size;
4431	err = ext4_mark_inode_dirty(handle, inode);
4432	if (err)
4433		return err;
4434
4435	last_block = (inode->i_size + sb->s_blocksize - 1)
4436			>> EXT4_BLOCK_SIZE_BITS(sb);
4437	ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
4438
4439retry_remove_space:
4440	err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4441	if (err == -ENOMEM) {
4442		memalloc_retry_wait(GFP_ATOMIC);
4443		goto retry_remove_space;
 
4444	}
4445	return err;
 
 
 
 
 
4446}
4447
4448static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4449				  ext4_lblk_t len, loff_t new_size,
4450				  int flags)
4451{
4452	struct inode *inode = file_inode(file);
4453	handle_t *handle;
4454	int ret = 0, ret2 = 0, ret3 = 0;
 
4455	int retries = 0;
4456	int depth = 0;
4457	struct ext4_map_blocks map;
4458	unsigned int credits;
4459	loff_t epos;
4460
4461	BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4462	map.m_lblk = offset;
4463	map.m_len = len;
4464	/*
4465	 * Don't normalize the request if it can fit in one extent so
4466	 * that it doesn't get unnecessarily split into multiple
4467	 * extents.
4468	 */
4469	if (len <= EXT_UNWRITTEN_MAX_LEN)
4470		flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4471
4472	/*
4473	 * credits to insert 1 extent into extent tree
4474	 */
4475	credits = ext4_chunk_trans_blocks(inode, len);
4476	depth = ext_depth(inode);
 
 
 
 
 
 
4477
4478retry:
4479	while (len) {
4480		/*
4481		 * Recalculate credits when extent tree depth changes.
4482		 */
4483		if (depth != ext_depth(inode)) {
4484			credits = ext4_chunk_trans_blocks(inode, len);
4485			depth = ext_depth(inode);
4486		}
4487
4488		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4489					    credits);
4490		if (IS_ERR(handle)) {
4491			ret = PTR_ERR(handle);
4492			break;
4493		}
4494		ret = ext4_map_blocks(handle, inode, &map, flags);
4495		if (ret <= 0) {
4496			ext4_debug("inode #%lu: block %u: len %u: "
4497				   "ext4_ext_map_blocks returned %d",
4498				   inode->i_ino, map.m_lblk,
4499				   map.m_len, ret);
4500			ext4_mark_inode_dirty(handle, inode);
4501			ext4_journal_stop(handle);
4502			break;
4503		}
4504		/*
4505		 * allow a full retry cycle for any remaining allocations
4506		 */
4507		retries = 0;
4508		map.m_lblk += ret;
4509		map.m_len = len = len - ret;
4510		epos = (loff_t)map.m_lblk << inode->i_blkbits;
4511		inode_set_ctime_current(inode);
4512		if (new_size) {
4513			if (epos > new_size)
4514				epos = new_size;
4515			if (ext4_update_inode_size(inode, epos) & 0x1)
4516				inode_set_mtime_to_ts(inode,
4517						      inode_get_ctime(inode));
4518		}
4519		ret2 = ext4_mark_inode_dirty(handle, inode);
4520		ext4_update_inode_fsync_trans(handle, inode, 1);
4521		ret3 = ext4_journal_stop(handle);
4522		ret2 = ret3 ? ret3 : ret2;
4523		if (unlikely(ret2))
 
4524			break;
4525	}
4526	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 
 
4527		goto retry;
 
4528
4529	return ret > 0 ? ret2 : ret;
4530}
4531
4532static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4533
4534static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4535
4536static long ext4_zero_range(struct file *file, loff_t offset,
4537			    loff_t len, int mode)
4538{
4539	struct inode *inode = file_inode(file);
4540	struct address_space *mapping = file->f_mapping;
4541	handle_t *handle = NULL;
4542	unsigned int max_blocks;
4543	loff_t new_size = 0;
4544	int ret = 0;
4545	int flags;
4546	int credits;
4547	int partial_begin, partial_end;
4548	loff_t start, end;
4549	ext4_lblk_t lblk;
4550	unsigned int blkbits = inode->i_blkbits;
4551
4552	trace_ext4_zero_range(inode, offset, len, mode);
4553
 
 
 
 
 
 
 
 
 
 
4554	/*
4555	 * Round up offset. This is not fallocate, we need to zero out
4556	 * blocks, so convert interior block aligned part of the range to
4557	 * unwritten and possibly manually zero out unaligned parts of the
4558	 * range. Here, start and partial_begin are inclusive, end and
4559	 * partial_end are exclusive.
4560	 */
4561	start = round_up(offset, 1 << blkbits);
4562	end = round_down((offset + len), 1 << blkbits);
4563
4564	if (start < offset || end > offset + len)
4565		return -EINVAL;
4566	partial_begin = offset & ((1 << blkbits) - 1);
4567	partial_end = (offset + len) & ((1 << blkbits) - 1);
4568
4569	lblk = start >> blkbits;
4570	max_blocks = (end >> blkbits);
4571	if (max_blocks < lblk)
4572		max_blocks = 0;
4573	else
4574		max_blocks -= lblk;
4575
4576	inode_lock(inode);
4577
4578	/*
4579	 * Indirect files do not support unwritten extents
4580	 */
4581	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4582		ret = -EOPNOTSUPP;
4583		goto out_mutex;
4584	}
4585
4586	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4587	    (offset + len > inode->i_size ||
4588	     offset + len > EXT4_I(inode)->i_disksize)) {
4589		new_size = offset + len;
4590		ret = inode_newsize_ok(inode, new_size);
4591		if (ret)
4592			goto out_mutex;
4593	}
4594
4595	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
 
 
4596
4597	/* Wait all existing dio workers, newcomers will block on i_rwsem */
 
4598	inode_dio_wait(inode);
4599
4600	ret = file_modified(file);
4601	if (ret)
4602		goto out_mutex;
4603
4604	/* Preallocate the range including the unaligned edges */
4605	if (partial_begin || partial_end) {
4606		ret = ext4_alloc_file_blocks(file,
4607				round_down(offset, 1 << blkbits) >> blkbits,
4608				(round_up((offset + len), 1 << blkbits) -
4609				 round_down(offset, 1 << blkbits)) >> blkbits,
4610				new_size, flags);
4611		if (ret)
4612			goto out_mutex;
4613
4614	}
4615
4616	/* Zero range excluding the unaligned edges */
4617	if (max_blocks > 0) {
4618		flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4619			  EXT4_EX_NOCACHE);
4620
4621		/*
4622		 * Prevent page faults from reinstantiating pages we have
4623		 * released from page cache.
4624		 */
4625		filemap_invalidate_lock(mapping);
4626
4627		ret = ext4_break_layouts(inode);
4628		if (ret) {
4629			filemap_invalidate_unlock(mapping);
4630			goto out_mutex;
4631		}
4632
4633		ret = ext4_update_disksize_before_punch(inode, offset, len);
4634		if (ret) {
4635			filemap_invalidate_unlock(mapping);
4636			goto out_mutex;
4637		}
4638
4639		/*
4640		 * For journalled data we need to write (and checkpoint) pages
4641		 * before discarding page cache to avoid inconsitent data on
4642		 * disk in case of crash before zeroing trans is committed.
4643		 */
4644		if (ext4_should_journal_data(inode)) {
4645			ret = filemap_write_and_wait_range(mapping, start,
4646							   end - 1);
4647			if (ret) {
4648				filemap_invalidate_unlock(mapping);
4649				goto out_mutex;
4650			}
4651		}
4652
4653		/* Now release the pages and zero block aligned part of pages */
4654		truncate_pagecache_range(inode, start, end - 1);
4655		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
4656
4657		ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4658					     flags);
4659		filemap_invalidate_unlock(mapping);
4660		if (ret)
4661			goto out_mutex;
4662	}
4663	if (!partial_begin && !partial_end)
4664		goto out_mutex;
4665
4666	/*
4667	 * In worst case we have to writeout two nonadjacent unwritten
4668	 * blocks and update the inode
4669	 */
4670	credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4671	if (ext4_should_journal_data(inode))
4672		credits += 2;
4673	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4674	if (IS_ERR(handle)) {
4675		ret = PTR_ERR(handle);
4676		ext4_std_error(inode->i_sb, ret);
4677		goto out_mutex;
4678	}
4679
4680	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
4681	if (new_size)
4682		ext4_update_inode_size(inode, new_size);
4683	ret = ext4_mark_inode_dirty(handle, inode);
4684	if (unlikely(ret))
4685		goto out_handle;
 
 
 
 
 
 
 
4686	/* Zero out partial block at the edges of the range */
4687	ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4688	if (ret >= 0)
4689		ext4_update_inode_fsync_trans(handle, inode, 1);
4690
4691	if (file->f_flags & O_SYNC)
4692		ext4_handle_sync(handle);
4693
4694out_handle:
4695	ext4_journal_stop(handle);
 
 
4696out_mutex:
4697	inode_unlock(inode);
4698	return ret;
4699}
4700
4701/*
4702 * preallocate space for a file. This implements ext4's fallocate file
4703 * operation, which gets called from sys_fallocate system call.
4704 * For block-mapped files, posix_fallocate should fall back to the method
4705 * of writing zeroes to the required new blocks (the same behavior which is
4706 * expected for file systems which do not support fallocate() system call).
4707 */
4708long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4709{
4710	struct inode *inode = file_inode(file);
4711	loff_t new_size = 0;
4712	unsigned int max_blocks;
4713	int ret = 0;
4714	int flags;
4715	ext4_lblk_t lblk;
4716	unsigned int blkbits = inode->i_blkbits;
4717
4718	/*
4719	 * Encrypted inodes can't handle collapse range or insert
4720	 * range since we would need to re-encrypt blocks with a
4721	 * different IV or XTS tweak (which are based on the logical
4722	 * block number).
4723	 */
4724	if (IS_ENCRYPTED(inode) &&
4725	    (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
 
 
 
 
 
4726		return -EOPNOTSUPP;
4727
4728	/* Return error if mode is not supported */
4729	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4730		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4731		     FALLOC_FL_INSERT_RANGE))
4732		return -EOPNOTSUPP;
4733
4734	inode_lock(inode);
 
 
4735	ret = ext4_convert_inline_data(inode);
4736	inode_unlock(inode);
4737	if (ret)
4738		goto exit;
4739
4740	if (mode & FALLOC_FL_PUNCH_HOLE) {
4741		ret = ext4_punch_hole(file, offset, len);
4742		goto exit;
4743	}
4744
4745	if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4746		ret = ext4_collapse_range(file, offset, len);
4747		goto exit;
4748	}
4749
4750	if (mode & FALLOC_FL_INSERT_RANGE) {
4751		ret = ext4_insert_range(file, offset, len);
4752		goto exit;
4753	}
4754
4755	if (mode & FALLOC_FL_ZERO_RANGE) {
4756		ret = ext4_zero_range(file, offset, len, mode);
4757		goto exit;
4758	}
4759	trace_ext4_fallocate_enter(inode, offset, len, mode);
4760	lblk = offset >> blkbits;
 
 
 
 
 
 
4761
4762	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4763	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
 
 
4764
4765	inode_lock(inode);
4766
4767	/*
4768	 * We only support preallocation for extent-based files only
4769	 */
4770	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4771		ret = -EOPNOTSUPP;
4772		goto out;
4773	}
4774
4775	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4776	    (offset + len > inode->i_size ||
4777	     offset + len > EXT4_I(inode)->i_disksize)) {
4778		new_size = offset + len;
4779		ret = inode_newsize_ok(inode, new_size);
4780		if (ret)
4781			goto out;
4782	}
4783
4784	/* Wait all existing dio workers, newcomers will block on i_rwsem */
 
4785	inode_dio_wait(inode);
4786
4787	ret = file_modified(file);
4788	if (ret)
4789		goto out;
4790
4791	ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4792	if (ret)
4793		goto out;
4794
4795	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4796		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4797					EXT4_I(inode)->i_sync_tid);
4798	}
4799out:
4800	inode_unlock(inode);
4801	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4802exit:
4803	return ret;
4804}
4805
4806/*
4807 * This function convert a range of blocks to written extents
4808 * The caller of this function will pass the start offset and the size.
4809 * all unwritten extents within this range will be converted to
4810 * written extents.
4811 *
4812 * This function is called from the direct IO end io call back
4813 * function, to convert the fallocated extents after IO is completed.
4814 * Returns 0 on success.
4815 */
4816int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4817				   loff_t offset, ssize_t len)
4818{
4819	unsigned int max_blocks;
4820	int ret = 0, ret2 = 0, ret3 = 0;
 
4821	struct ext4_map_blocks map;
4822	unsigned int blkbits = inode->i_blkbits;
4823	unsigned int credits = 0;
4824
4825	map.m_lblk = offset >> blkbits;
4826	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4827
4828	if (!handle) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4829		/*
4830		 * credits to insert 1 extent into extent tree
4831		 */
4832		credits = ext4_chunk_trans_blocks(inode, max_blocks);
4833	}
4834	while (ret >= 0 && ret < max_blocks) {
4835		map.m_lblk += ret;
4836		map.m_len = (max_blocks -= ret);
4837		if (credits) {
4838			handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4839						    credits);
4840			if (IS_ERR(handle)) {
4841				ret = PTR_ERR(handle);
4842				break;
4843			}
4844		}
4845		ret = ext4_map_blocks(handle, inode, &map,
4846				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4847		if (ret <= 0)
4848			ext4_warning(inode->i_sb,
4849				     "inode #%lu: block %u: len %u: "
4850				     "ext4_ext_map_blocks returned %d",
4851				     inode->i_ino, map.m_lblk,
4852				     map.m_len, ret);
4853		ret2 = ext4_mark_inode_dirty(handle, inode);
4854		if (credits) {
4855			ret3 = ext4_journal_stop(handle);
4856			if (unlikely(ret3))
4857				ret2 = ret3;
4858		}
4859
4860		if (ret <= 0 || ret2)
4861			break;
4862	}
 
 
4863	return ret > 0 ? ret2 : ret;
4864}
4865
4866int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
 
 
 
 
 
 
 
 
 
 
4867{
4868	int ret = 0, err = 0;
4869	struct ext4_io_end_vec *io_end_vec;
 
 
 
 
4870
4871	/*
4872	 * This is somewhat ugly but the idea is clear: When transaction is
4873	 * reserved, everything goes into it. Otherwise we rather start several
4874	 * smaller transactions for conversion of each extent separately.
4875	 */
4876	if (handle) {
4877		handle = ext4_journal_start_reserved(handle,
4878						     EXT4_HT_EXT_CONVERT);
4879		if (IS_ERR(handle))
4880			return PTR_ERR(handle);
4881	}
 
 
 
4882
4883	list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4884		ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4885						     io_end_vec->offset,
4886						     io_end_vec->size);
4887		if (ret)
4888			break;
4889	}
4890
4891	if (handle)
4892		err = ext4_journal_stop(handle);
 
 
 
 
4893
4894	return ret < 0 ? ret : err;
4895}
 
 
4896
4897static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
 
4898{
4899	__u64 physical = 0;
4900	__u64 length = 0;
 
4901	int blockbits = inode->i_sb->s_blocksize_bits;
4902	int error = 0;
4903	u16 iomap_type;
4904
4905	/* in-inode? */
4906	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4907		struct ext4_iloc iloc;
4908		int offset;	/* offset of xattr in inode */
4909
4910		error = ext4_get_inode_loc(inode, &iloc);
4911		if (error)
4912			return error;
4913		physical = (__u64)iloc.bh->b_blocknr << blockbits;
4914		offset = EXT4_GOOD_OLD_INODE_SIZE +
4915				EXT4_I(inode)->i_extra_isize;
4916		physical += offset;
4917		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
 
4918		brelse(iloc.bh);
4919		iomap_type = IOMAP_INLINE;
4920	} else if (EXT4_I(inode)->i_file_acl) { /* external block */
4921		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4922		length = inode->i_sb->s_blocksize;
4923		iomap_type = IOMAP_MAPPED;
4924	} else {
4925		/* no in-inode or external block for xattr, so return -ENOENT */
4926		error = -ENOENT;
4927		goto out;
4928	}
4929
4930	iomap->addr = physical;
4931	iomap->offset = 0;
4932	iomap->length = length;
4933	iomap->type = iomap_type;
4934	iomap->flags = 0;
4935out:
4936	return error;
4937}
4938
4939static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4940				  loff_t length, unsigned flags,
4941				  struct iomap *iomap, struct iomap *srcmap)
4942{
4943	int error;
4944
4945	error = ext4_iomap_xattr_fiemap(inode, iomap);
4946	if (error == 0 && (offset >= iomap->length))
4947		error = -ENOENT;
4948	return error;
4949}
4950
4951static const struct iomap_ops ext4_iomap_xattr_ops = {
4952	.iomap_begin		= ext4_iomap_xattr_begin,
4953};
4954
4955static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4956{
4957	u64 maxbytes;
 
4958
4959	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4960		maxbytes = inode->i_sb->s_maxbytes;
4961	else
4962		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4963
4964	if (*len == 0)
4965		return -EINVAL;
4966	if (start > maxbytes)
4967		return -EFBIG;
4968
4969	/*
4970	 * Shrink request scope to what the fs can actually handle.
4971	 */
4972	if (*len > maxbytes || (maxbytes - *len) < start)
4973		*len = maxbytes - start;
4974	return 0;
4975}
4976
4977int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4978		u64 start, u64 len)
4979{
4980	int error = 0;
4981
4982	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4983		error = ext4_ext_precache(inode);
4984		if (error)
4985			return error;
4986		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4987	}
4988
4989	/*
4990	 * For bitmap files the maximum size limit could be smaller than
4991	 * s_maxbytes, so check len here manually instead of just relying on the
4992	 * generic check.
4993	 */
4994	error = ext4_fiemap_check_ranges(inode, start, &len);
4995	if (error)
4996		return error;
4997
4998	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4999		fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
5000		return iomap_fiemap(inode, fieinfo, start, len,
5001				    &ext4_iomap_xattr_ops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5002	}
5003
5004	return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
5005}
5006
5007int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
5008		      __u64 start, __u64 len)
 
 
 
 
 
 
 
5009{
5010	ext4_lblk_t start_blk, len_blks;
5011	__u64 last_blk;
5012	int error = 0;
5013
5014	if (ext4_has_inline_data(inode)) {
5015		int has_inline;
5016
5017		down_read(&EXT4_I(inode)->xattr_sem);
5018		has_inline = ext4_has_inline_data(inode);
5019		up_read(&EXT4_I(inode)->xattr_sem);
5020		if (has_inline)
5021			return 0;
 
 
 
 
 
 
 
5022	}
5023
5024	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5025		error = ext4_ext_precache(inode);
5026		if (error)
5027			return error;
5028		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5029	}
5030
5031	error = fiemap_prep(inode, fieinfo, start, &len, 0);
5032	if (error)
5033		return error;
5034
5035	error = ext4_fiemap_check_ranges(inode, start, &len);
5036	if (error)
5037		return error;
5038
5039	start_blk = start >> inode->i_sb->s_blocksize_bits;
5040	last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5041	if (last_blk >= EXT_MAX_BLOCKS)
5042		last_blk = EXT_MAX_BLOCKS-1;
5043	len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5044
5045	/*
5046	 * Walk the extent tree gathering extent information
5047	 * and pushing extents back to the user.
5048	 */
5049	return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5050}
5051
5052/*
5053 * ext4_ext_shift_path_extents:
5054 * Shift the extents of a path structure lying between path[depth].p_ext
5055 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5056 * if it is right shift or left shift operation.
5057 */
5058static int
5059ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5060			    struct inode *inode, handle_t *handle,
5061			    enum SHIFT_DIRECTION SHIFT)
5062{
5063	int depth, err = 0;
5064	struct ext4_extent *ex_start, *ex_last;
5065	bool update = false;
5066	int credits, restart_credits;
5067	depth = path->p_depth;
5068
5069	while (depth >= 0) {
5070		if (depth == path->p_depth) {
5071			ex_start = path[depth].p_ext;
5072			if (!ex_start)
5073				return -EFSCORRUPTED;
5074
5075			ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5076			/* leaf + sb + inode */
5077			credits = 3;
5078			if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5079				update = true;
5080				/* extent tree + sb + inode */
5081				credits = depth + 2;
5082			}
5083
5084			restart_credits = ext4_writepage_trans_blocks(inode);
5085			err = ext4_datasem_ensure_credits(handle, inode, credits,
5086					restart_credits, 0);
5087			if (err) {
5088				if (err > 0)
5089					err = -EAGAIN;
5090				goto out;
5091			}
5092
5093			err = ext4_ext_get_access(handle, inode, path + depth);
5094			if (err)
5095				goto out;
5096
5097			while (ex_start <= ex_last) {
5098				if (SHIFT == SHIFT_LEFT) {
5099					le32_add_cpu(&ex_start->ee_block,
5100						-shift);
5101					/* Try to merge to the left. */
5102					if ((ex_start >
5103					    EXT_FIRST_EXTENT(path[depth].p_hdr))
5104					    &&
5105					    ext4_ext_try_to_merge_right(inode,
5106					    path, ex_start - 1))
5107						ex_last--;
5108					else
5109						ex_start++;
5110				} else {
5111					le32_add_cpu(&ex_last->ee_block, shift);
5112					ext4_ext_try_to_merge_right(inode, path,
5113						ex_last);
5114					ex_last--;
5115				}
5116			}
5117			err = ext4_ext_dirty(handle, inode, path + depth);
5118			if (err)
5119				goto out;
5120
5121			if (--depth < 0 || !update)
5122				break;
5123		}
5124
5125		/* Update index too */
5126		err = ext4_ext_get_access(handle, inode, path + depth);
5127		if (err)
5128			goto out;
5129
5130		if (SHIFT == SHIFT_LEFT)
5131			le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5132		else
5133			le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5134		err = ext4_ext_dirty(handle, inode, path + depth);
5135		if (err)
5136			goto out;
5137
5138		/* we are done if current index is not a starting index */
5139		if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5140			break;
5141
5142		depth--;
5143	}
5144
5145out:
5146	return err;
5147}
5148
5149/*
5150 * ext4_ext_shift_extents:
5151 * All the extents which lies in the range from @start to the last allocated
5152 * block for the @inode are shifted either towards left or right (depending
5153 * upon @SHIFT) by @shift blocks.
5154 * On success, 0 is returned, error otherwise.
5155 */
5156static int
5157ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5158		       ext4_lblk_t start, ext4_lblk_t shift,
5159		       enum SHIFT_DIRECTION SHIFT)
5160{
5161	struct ext4_ext_path *path;
5162	int ret = 0, depth;
5163	struct ext4_extent *extent;
5164	ext4_lblk_t stop, *iterator, ex_start, ex_end;
5165	ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5166
5167	/* Let path point to the last extent */
5168	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5169				EXT4_EX_NOCACHE);
5170	if (IS_ERR(path))
5171		return PTR_ERR(path);
5172
5173	depth = path->p_depth;
5174	extent = path[depth].p_ext;
5175	if (!extent)
5176		goto out;
5177
5178	stop = le32_to_cpu(extent->ee_block);
 
5179
5180       /*
5181	* For left shifts, make sure the hole on the left is big enough to
5182	* accommodate the shift.  For right shifts, make sure the last extent
5183	* won't be shifted beyond EXT_MAX_BLOCKS.
5184	*/
5185	if (SHIFT == SHIFT_LEFT) {
5186		path = ext4_find_extent(inode, start - 1, &path,
5187					EXT4_EX_NOCACHE);
5188		if (IS_ERR(path))
5189			return PTR_ERR(path);
5190		depth = path->p_depth;
5191		extent =  path[depth].p_ext;
5192		if (extent) {
5193			ex_start = le32_to_cpu(extent->ee_block);
5194			ex_end = le32_to_cpu(extent->ee_block) +
5195				ext4_ext_get_actual_len(extent);
5196		} else {
5197			ex_start = 0;
5198			ex_end = 0;
5199		}
5200
5201		if ((start == ex_start && shift > ex_start) ||
5202		    (shift > start - ex_end)) {
5203			ret = -EINVAL;
5204			goto out;
5205		}
5206	} else {
5207		if (shift > EXT_MAX_BLOCKS -
5208		    (stop + ext4_ext_get_actual_len(extent))) {
5209			ret = -EINVAL;
5210			goto out;
5211		}
5212	}
5213
5214	/*
5215	 * In case of left shift, iterator points to start and it is increased
5216	 * till we reach stop. In case of right shift, iterator points to stop
5217	 * and it is decreased till we reach start.
5218	 */
5219again:
5220	ret = 0;
5221	if (SHIFT == SHIFT_LEFT)
5222		iterator = &start;
5223	else
5224		iterator = &stop;
5225
5226	if (tmp != EXT_MAX_BLOCKS)
5227		*iterator = tmp;
5228
5229	/*
5230	 * Its safe to start updating extents.  Start and stop are unsigned, so
5231	 * in case of right shift if extent with 0 block is reached, iterator
5232	 * becomes NULL to indicate the end of the loop.
5233	 */
5234	while (iterator && start <= stop) {
5235		path = ext4_find_extent(inode, *iterator, &path,
5236					EXT4_EX_NOCACHE);
5237		if (IS_ERR(path))
5238			return PTR_ERR(path);
5239		depth = path->p_depth;
5240		extent = path[depth].p_ext;
5241		if (!extent) {
5242			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5243					 (unsigned long) *iterator);
5244			return -EFSCORRUPTED;
5245		}
5246		if (SHIFT == SHIFT_LEFT && *iterator >
5247		    le32_to_cpu(extent->ee_block)) {
5248			/* Hole, move to the next extent */
5249			if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5250				path[depth].p_ext++;
5251			} else {
5252				*iterator = ext4_ext_next_allocated_block(path);
5253				continue;
5254			}
5255		}
5256
5257		tmp = *iterator;
5258		if (SHIFT == SHIFT_LEFT) {
5259			extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5260			*iterator = le32_to_cpu(extent->ee_block) +
5261					ext4_ext_get_actual_len(extent);
5262		} else {
5263			extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5264			if (le32_to_cpu(extent->ee_block) > start)
5265				*iterator = le32_to_cpu(extent->ee_block) - 1;
5266			else if (le32_to_cpu(extent->ee_block) == start)
5267				iterator = NULL;
5268			else {
5269				extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5270				while (le32_to_cpu(extent->ee_block) >= start)
5271					extent--;
5272
5273				if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
5274					break;
5275
5276				extent++;
5277				iterator = NULL;
5278			}
5279			path[depth].p_ext = extent;
5280		}
5281		ret = ext4_ext_shift_path_extents(path, shift, inode,
5282				handle, SHIFT);
5283		/* iterator can be NULL which means we should break */
5284		if (ret == -EAGAIN)
5285			goto again;
5286		if (ret)
5287			break;
5288	}
5289out:
5290	ext4_free_ext_path(path);
 
5291	return ret;
5292}
5293
5294/*
5295 * ext4_collapse_range:
5296 * This implements the fallocate's collapse range functionality for ext4
5297 * Returns: 0 and non-zero on error.
5298 */
5299static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5300{
5301	struct inode *inode = file_inode(file);
5302	struct super_block *sb = inode->i_sb;
5303	struct address_space *mapping = inode->i_mapping;
5304	ext4_lblk_t punch_start, punch_stop;
5305	handle_t *handle;
5306	unsigned int credits;
5307	loff_t new_size, ioffset;
5308	int ret;
5309
5310	/*
5311	 * We need to test this early because xfstests assumes that a
5312	 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5313	 * system does not support collapse range.
5314	 */
5315	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5316		return -EOPNOTSUPP;
5317
5318	/* Collapse range works only on fs cluster size aligned regions. */
5319	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
 
 
 
 
5320		return -EINVAL;
5321
5322	trace_ext4_collapse_range(inode, offset, len);
5323
5324	punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5325	punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5326
 
 
 
 
 
 
 
5327	inode_lock(inode);
5328	/*
5329	 * There is no need to overlap collapse range with EOF, in which case
5330	 * it is effectively a truncate operation
5331	 */
5332	if (offset + len >= inode->i_size) {
5333		ret = -EINVAL;
5334		goto out_mutex;
5335	}
5336
5337	/* Currently just for extent based files */
5338	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5339		ret = -EOPNOTSUPP;
5340		goto out_mutex;
5341	}
5342
5343	/* Wait for existing dio to complete */
 
5344	inode_dio_wait(inode);
5345
5346	ret = file_modified(file);
5347	if (ret)
5348		goto out_mutex;
5349
5350	/*
5351	 * Prevent page faults from reinstantiating pages we have released from
5352	 * page cache.
5353	 */
5354	filemap_invalidate_lock(mapping);
5355
5356	ret = ext4_break_layouts(inode);
5357	if (ret)
5358		goto out_mmap;
5359
5360	/*
5361	 * Need to round down offset to be aligned with page size boundary
5362	 * for page size > block size.
5363	 */
5364	ioffset = round_down(offset, PAGE_SIZE);
5365	/*
5366	 * Write tail of the last page before removed range since it will get
5367	 * removed from the page cache below.
5368	 */
5369	ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5370	if (ret)
5371		goto out_mmap;
5372	/*
5373	 * Write data that will be shifted to preserve them when discarding
5374	 * page cache below. We are also protected from pages becoming dirty
5375	 * by i_rwsem and invalidate_lock.
5376	 */
5377	ret = filemap_write_and_wait_range(mapping, offset + len,
5378					   LLONG_MAX);
5379	if (ret)
5380		goto out_mmap;
5381	truncate_pagecache(inode, ioffset);
5382
5383	credits = ext4_writepage_trans_blocks(inode);
5384	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5385	if (IS_ERR(handle)) {
5386		ret = PTR_ERR(handle);
5387		goto out_mmap;
5388	}
5389	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5390
5391	down_write(&EXT4_I(inode)->i_data_sem);
5392	ext4_discard_preallocations(inode);
5393	ext4_es_remove_extent(inode, punch_start, EXT_MAX_BLOCKS - punch_start);
 
 
 
 
 
 
5394
5395	ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5396	if (ret) {
5397		up_write(&EXT4_I(inode)->i_data_sem);
5398		goto out_stop;
5399	}
5400	ext4_discard_preallocations(inode);
5401
5402	ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5403				     punch_stop - punch_start, SHIFT_LEFT);
5404	if (ret) {
5405		up_write(&EXT4_I(inode)->i_data_sem);
5406		goto out_stop;
5407	}
5408
5409	new_size = inode->i_size - len;
5410	i_size_write(inode, new_size);
5411	EXT4_I(inode)->i_disksize = new_size;
5412
5413	up_write(&EXT4_I(inode)->i_data_sem);
5414	if (IS_SYNC(inode))
5415		ext4_handle_sync(handle);
5416	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
5417	ret = ext4_mark_inode_dirty(handle, inode);
5418	ext4_update_inode_fsync_trans(handle, inode, 1);
5419
5420out_stop:
5421	ext4_journal_stop(handle);
5422out_mmap:
5423	filemap_invalidate_unlock(mapping);
 
5424out_mutex:
5425	inode_unlock(inode);
5426	return ret;
5427}
5428
5429/*
5430 * ext4_insert_range:
5431 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5432 * The data blocks starting from @offset to the EOF are shifted by @len
5433 * towards right to create a hole in the @inode. Inode size is increased
5434 * by len bytes.
5435 * Returns 0 on success, error otherwise.
5436 */
5437static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5438{
5439	struct inode *inode = file_inode(file);
5440	struct super_block *sb = inode->i_sb;
5441	struct address_space *mapping = inode->i_mapping;
5442	handle_t *handle;
5443	struct ext4_ext_path *path;
5444	struct ext4_extent *extent;
5445	ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5446	unsigned int credits, ee_len;
5447	int ret = 0, depth, split_flag = 0;
5448	loff_t ioffset;
5449
5450	/*
5451	 * We need to test this early because xfstests assumes that an
5452	 * insert range of (0, 1) will return EOPNOTSUPP if the file
5453	 * system does not support insert range.
5454	 */
5455	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5456		return -EOPNOTSUPP;
5457
5458	/* Insert range works only on fs cluster size aligned regions. */
5459	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
 
5460		return -EINVAL;
5461
 
 
 
5462	trace_ext4_insert_range(inode, offset, len);
5463
5464	offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5465	len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5466
 
 
 
 
 
 
 
5467	inode_lock(inode);
5468	/* Currently just for extent based files */
5469	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5470		ret = -EOPNOTSUPP;
5471		goto out_mutex;
5472	}
5473
5474	/* Check whether the maximum file size would be exceeded */
5475	if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5476		ret = -EFBIG;
5477		goto out_mutex;
5478	}
5479
5480	/* Offset must be less than i_size */
5481	if (offset >= inode->i_size) {
5482		ret = -EINVAL;
5483		goto out_mutex;
5484	}
5485
5486	/* Wait for existing dio to complete */
 
5487	inode_dio_wait(inode);
5488
5489	ret = file_modified(file);
5490	if (ret)
5491		goto out_mutex;
5492
5493	/*
5494	 * Prevent page faults from reinstantiating pages we have released from
5495	 * page cache.
5496	 */
5497	filemap_invalidate_lock(mapping);
5498
5499	ret = ext4_break_layouts(inode);
5500	if (ret)
5501		goto out_mmap;
5502
5503	/*
5504	 * Need to round down to align start offset to page size boundary
5505	 * for page size > block size.
5506	 */
5507	ioffset = round_down(offset, PAGE_SIZE);
5508	/* Write out all dirty pages */
5509	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5510			LLONG_MAX);
5511	if (ret)
5512		goto out_mmap;
5513	truncate_pagecache(inode, ioffset);
5514
5515	credits = ext4_writepage_trans_blocks(inode);
5516	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5517	if (IS_ERR(handle)) {
5518		ret = PTR_ERR(handle);
5519		goto out_mmap;
5520	}
5521	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5522
5523	/* Expand file to avoid data loss if there is error while shifting */
5524	inode->i_size += len;
5525	EXT4_I(inode)->i_disksize += len;
5526	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
5527	ret = ext4_mark_inode_dirty(handle, inode);
5528	if (ret)
5529		goto out_stop;
5530
5531	down_write(&EXT4_I(inode)->i_data_sem);
5532	ext4_discard_preallocations(inode);
5533
5534	path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5535	if (IS_ERR(path)) {
5536		up_write(&EXT4_I(inode)->i_data_sem);
5537		goto out_stop;
5538	}
5539
5540	depth = ext_depth(inode);
5541	extent = path[depth].p_ext;
5542	if (extent) {
5543		ee_start_lblk = le32_to_cpu(extent->ee_block);
5544		ee_len = ext4_ext_get_actual_len(extent);
5545
5546		/*
5547		 * If offset_lblk is not the starting block of extent, split
5548		 * the extent @offset_lblk
5549		 */
5550		if ((offset_lblk > ee_start_lblk) &&
5551				(offset_lblk < (ee_start_lblk + ee_len))) {
5552			if (ext4_ext_is_unwritten(extent))
5553				split_flag = EXT4_EXT_MARK_UNWRIT1 |
5554					EXT4_EXT_MARK_UNWRIT2;
5555			ret = ext4_split_extent_at(handle, inode, &path,
5556					offset_lblk, split_flag,
5557					EXT4_EX_NOCACHE |
5558					EXT4_GET_BLOCKS_PRE_IO |
5559					EXT4_GET_BLOCKS_METADATA_NOFAIL);
5560		}
5561
5562		ext4_free_ext_path(path);
 
5563		if (ret < 0) {
5564			up_write(&EXT4_I(inode)->i_data_sem);
5565			goto out_stop;
5566		}
5567	} else {
5568		ext4_free_ext_path(path);
5569	}
5570
5571	ext4_es_remove_extent(inode, offset_lblk, EXT_MAX_BLOCKS - offset_lblk);
 
 
 
 
 
5572
5573	/*
5574	 * if offset_lblk lies in a hole which is at start of file, use
5575	 * ee_start_lblk to shift extents
5576	 */
5577	ret = ext4_ext_shift_extents(inode, handle,
5578		max(ee_start_lblk, offset_lblk), len_lblk, SHIFT_RIGHT);
 
5579
5580	up_write(&EXT4_I(inode)->i_data_sem);
5581	if (IS_SYNC(inode))
5582		ext4_handle_sync(handle);
5583	if (ret >= 0)
5584		ext4_update_inode_fsync_trans(handle, inode, 1);
5585
5586out_stop:
5587	ext4_journal_stop(handle);
5588out_mmap:
5589	filemap_invalidate_unlock(mapping);
 
5590out_mutex:
5591	inode_unlock(inode);
5592	return ret;
5593}
5594
5595/**
5596 * ext4_swap_extents() - Swap extents between two inodes
5597 * @handle: handle for this transaction
5598 * @inode1:	First inode
5599 * @inode2:	Second inode
5600 * @lblk1:	Start block for first inode
5601 * @lblk2:	Start block for second inode
5602 * @count:	Number of blocks to swap
5603 * @unwritten: Mark second inode's extents as unwritten after swap
5604 * @erp:	Pointer to save error value
5605 *
5606 * This helper routine does exactly what is promise "swap extents". All other
5607 * stuff such as page-cache locking consistency, bh mapping consistency or
5608 * extent's data copying must be performed by caller.
5609 * Locking:
5610 *		i_rwsem is held for both inodes
5611 * 		i_data_sem is locked for write for both inodes
5612 * Assumptions:
5613 *		All pages from requested range are locked for both inodes
5614 */
5615int
5616ext4_swap_extents(handle_t *handle, struct inode *inode1,
5617		  struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5618		  ext4_lblk_t count, int unwritten, int *erp)
5619{
5620	struct ext4_ext_path *path1 = NULL;
5621	struct ext4_ext_path *path2 = NULL;
5622	int replaced_count = 0;
5623
5624	BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5625	BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5626	BUG_ON(!inode_is_locked(inode1));
5627	BUG_ON(!inode_is_locked(inode2));
5628
5629	ext4_es_remove_extent(inode1, lblk1, count);
5630	ext4_es_remove_extent(inode2, lblk2, count);
 
 
 
 
5631
5632	while (count) {
5633		struct ext4_extent *ex1, *ex2, tmp_ex;
5634		ext4_lblk_t e1_blk, e2_blk;
5635		int e1_len, e2_len, len;
5636		int split = 0;
5637
5638		path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5639		if (IS_ERR(path1)) {
5640			*erp = PTR_ERR(path1);
5641			path1 = NULL;
5642		finish:
5643			count = 0;
5644			goto repeat;
5645		}
5646		path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5647		if (IS_ERR(path2)) {
5648			*erp = PTR_ERR(path2);
5649			path2 = NULL;
5650			goto finish;
5651		}
5652		ex1 = path1[path1->p_depth].p_ext;
5653		ex2 = path2[path2->p_depth].p_ext;
5654		/* Do we have something to swap ? */
5655		if (unlikely(!ex2 || !ex1))
5656			goto finish;
5657
5658		e1_blk = le32_to_cpu(ex1->ee_block);
5659		e2_blk = le32_to_cpu(ex2->ee_block);
5660		e1_len = ext4_ext_get_actual_len(ex1);
5661		e2_len = ext4_ext_get_actual_len(ex2);
5662
5663		/* Hole handling */
5664		if (!in_range(lblk1, e1_blk, e1_len) ||
5665		    !in_range(lblk2, e2_blk, e2_len)) {
5666			ext4_lblk_t next1, next2;
5667
5668			/* if hole after extent, then go to next extent */
5669			next1 = ext4_ext_next_allocated_block(path1);
5670			next2 = ext4_ext_next_allocated_block(path2);
5671			/* If hole before extent, then shift to that extent */
5672			if (e1_blk > lblk1)
5673				next1 = e1_blk;
5674			if (e2_blk > lblk2)
5675				next2 = e2_blk;
5676			/* Do we have something to swap */
5677			if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5678				goto finish;
5679			/* Move to the rightest boundary */
5680			len = next1 - lblk1;
5681			if (len < next2 - lblk2)
5682				len = next2 - lblk2;
5683			if (len > count)
5684				len = count;
5685			lblk1 += len;
5686			lblk2 += len;
5687			count -= len;
5688			goto repeat;
5689		}
5690
5691		/* Prepare left boundary */
5692		if (e1_blk < lblk1) {
5693			split = 1;
5694			*erp = ext4_force_split_extent_at(handle, inode1,
5695						&path1, lblk1, 0);
5696			if (unlikely(*erp))
5697				goto finish;
5698		}
5699		if (e2_blk < lblk2) {
5700			split = 1;
5701			*erp = ext4_force_split_extent_at(handle, inode2,
5702						&path2,  lblk2, 0);
5703			if (unlikely(*erp))
5704				goto finish;
5705		}
5706		/* ext4_split_extent_at() may result in leaf extent split,
5707		 * path must to be revalidated. */
5708		if (split)
5709			goto repeat;
5710
5711		/* Prepare right boundary */
5712		len = count;
5713		if (len > e1_blk + e1_len - lblk1)
5714			len = e1_blk + e1_len - lblk1;
5715		if (len > e2_blk + e2_len - lblk2)
5716			len = e2_blk + e2_len - lblk2;
5717
5718		if (len != e1_len) {
5719			split = 1;
5720			*erp = ext4_force_split_extent_at(handle, inode1,
5721						&path1, lblk1 + len, 0);
5722			if (unlikely(*erp))
5723				goto finish;
5724		}
5725		if (len != e2_len) {
5726			split = 1;
5727			*erp = ext4_force_split_extent_at(handle, inode2,
5728						&path2, lblk2 + len, 0);
5729			if (*erp)
5730				goto finish;
5731		}
5732		/* ext4_split_extent_at() may result in leaf extent split,
5733		 * path must to be revalidated. */
5734		if (split)
5735			goto repeat;
5736
5737		BUG_ON(e2_len != e1_len);
5738		*erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5739		if (unlikely(*erp))
5740			goto finish;
5741		*erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5742		if (unlikely(*erp))
5743			goto finish;
5744
5745		/* Both extents are fully inside boundaries. Swap it now */
5746		tmp_ex = *ex1;
5747		ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5748		ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5749		ex1->ee_len = cpu_to_le16(e2_len);
5750		ex2->ee_len = cpu_to_le16(e1_len);
5751		if (unwritten)
5752			ext4_ext_mark_unwritten(ex2);
5753		if (ext4_ext_is_unwritten(&tmp_ex))
5754			ext4_ext_mark_unwritten(ex1);
5755
5756		ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5757		ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5758		*erp = ext4_ext_dirty(handle, inode2, path2 +
5759				      path2->p_depth);
5760		if (unlikely(*erp))
5761			goto finish;
5762		*erp = ext4_ext_dirty(handle, inode1, path1 +
5763				      path1->p_depth);
5764		/*
5765		 * Looks scarry ah..? second inode already points to new blocks,
5766		 * and it was successfully dirtied. But luckily error may happen
5767		 * only due to journal error, so full transaction will be
5768		 * aborted anyway.
5769		 */
5770		if (unlikely(*erp))
5771			goto finish;
5772		lblk1 += len;
5773		lblk2 += len;
5774		replaced_count += len;
5775		count -= len;
5776
5777	repeat:
5778		ext4_free_ext_path(path1);
5779		ext4_free_ext_path(path2);
 
 
5780		path1 = path2 = NULL;
5781	}
5782	return replaced_count;
5783}
5784
5785/*
5786 * ext4_clu_mapped - determine whether any block in a logical cluster has
5787 *                   been mapped to a physical cluster
5788 *
5789 * @inode - file containing the logical cluster
5790 * @lclu - logical cluster of interest
5791 *
5792 * Returns 1 if any block in the logical cluster is mapped, signifying
5793 * that a physical cluster has been allocated for it.  Otherwise,
5794 * returns 0.  Can also return negative error codes.  Derived from
5795 * ext4_ext_map_blocks().
5796 */
5797int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5798{
5799	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5800	struct ext4_ext_path *path;
5801	int depth, mapped = 0, err = 0;
5802	struct ext4_extent *extent;
5803	ext4_lblk_t first_lblk, first_lclu, last_lclu;
5804
5805	/*
5806	 * if data can be stored inline, the logical cluster isn't
5807	 * mapped - no physical clusters have been allocated, and the
5808	 * file has no extents
5809	 */
5810	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||
5811	    ext4_has_inline_data(inode))
5812		return 0;
5813
5814	/* search for the extent closest to the first block in the cluster */
5815	path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5816	if (IS_ERR(path)) {
5817		err = PTR_ERR(path);
5818		path = NULL;
5819		goto out;
5820	}
5821
5822	depth = ext_depth(inode);
5823
5824	/*
5825	 * A consistent leaf must not be empty.  This situation is possible,
5826	 * though, _during_ tree modification, and it's why an assert can't
5827	 * be put in ext4_find_extent().
5828	 */
5829	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5830		EXT4_ERROR_INODE(inode,
5831		    "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5832				 (unsigned long) EXT4_C2B(sbi, lclu),
5833				 depth, path[depth].p_block);
5834		err = -EFSCORRUPTED;
5835		goto out;
5836	}
5837
5838	extent = path[depth].p_ext;
5839
5840	/* can't be mapped if the extent tree is empty */
5841	if (extent == NULL)
5842		goto out;
5843
5844	first_lblk = le32_to_cpu(extent->ee_block);
5845	first_lclu = EXT4_B2C(sbi, first_lblk);
5846
5847	/*
5848	 * Three possible outcomes at this point - found extent spanning
5849	 * the target cluster, to the left of the target cluster, or to the
5850	 * right of the target cluster.  The first two cases are handled here.
5851	 * The last case indicates the target cluster is not mapped.
5852	 */
5853	if (lclu >= first_lclu) {
5854		last_lclu = EXT4_B2C(sbi, first_lblk +
5855				     ext4_ext_get_actual_len(extent) - 1);
5856		if (lclu <= last_lclu) {
5857			mapped = 1;
5858		} else {
5859			first_lblk = ext4_ext_next_allocated_block(path);
5860			first_lclu = EXT4_B2C(sbi, first_lblk);
5861			if (lclu == first_lclu)
5862				mapped = 1;
5863		}
5864	}
5865
5866out:
5867	ext4_free_ext_path(path);
5868
5869	return err ? err : mapped;
5870}
5871
5872/*
5873 * Updates physical block address and unwritten status of extent
5874 * starting at lblk start and of len. If such an extent doesn't exist,
5875 * this function splits the extent tree appropriately to create an
5876 * extent like this.  This function is called in the fast commit
5877 * replay path.  Returns 0 on success and error on failure.
5878 */
5879int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5880			      int len, int unwritten, ext4_fsblk_t pblk)
5881{
5882	struct ext4_ext_path *path = NULL, *ppath;
5883	struct ext4_extent *ex;
5884	int ret;
5885
5886	path = ext4_find_extent(inode, start, NULL, 0);
5887	if (IS_ERR(path))
5888		return PTR_ERR(path);
5889	ex = path[path->p_depth].p_ext;
5890	if (!ex) {
5891		ret = -EFSCORRUPTED;
5892		goto out;
5893	}
5894
5895	if (le32_to_cpu(ex->ee_block) != start ||
5896		ext4_ext_get_actual_len(ex) != len) {
5897		/* We need to split this extent to match our extent first */
5898		ppath = path;
5899		down_write(&EXT4_I(inode)->i_data_sem);
5900		ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
5901		up_write(&EXT4_I(inode)->i_data_sem);
5902		if (ret)
5903			goto out;
5904		kfree(path);
5905		path = ext4_find_extent(inode, start, NULL, 0);
5906		if (IS_ERR(path))
5907			return -1;
5908		ppath = path;
5909		ex = path[path->p_depth].p_ext;
5910		WARN_ON(le32_to_cpu(ex->ee_block) != start);
5911		if (ext4_ext_get_actual_len(ex) != len) {
5912			down_write(&EXT4_I(inode)->i_data_sem);
5913			ret = ext4_force_split_extent_at(NULL, inode, &ppath,
5914							 start + len, 1);
5915			up_write(&EXT4_I(inode)->i_data_sem);
5916			if (ret)
5917				goto out;
5918			kfree(path);
5919			path = ext4_find_extent(inode, start, NULL, 0);
5920			if (IS_ERR(path))
5921				return -EINVAL;
5922			ex = path[path->p_depth].p_ext;
5923		}
5924	}
5925	if (unwritten)
5926		ext4_ext_mark_unwritten(ex);
5927	else
5928		ext4_ext_mark_initialized(ex);
5929	ext4_ext_store_pblock(ex, pblk);
5930	down_write(&EXT4_I(inode)->i_data_sem);
5931	ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5932	up_write(&EXT4_I(inode)->i_data_sem);
5933out:
5934	ext4_free_ext_path(path);
5935	ext4_mark_inode_dirty(NULL, inode);
5936	return ret;
5937}
5938
5939/* Try to shrink the extent tree */
5940void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5941{
5942	struct ext4_ext_path *path = NULL;
5943	struct ext4_extent *ex;
5944	ext4_lblk_t old_cur, cur = 0;
5945
5946	while (cur < end) {
5947		path = ext4_find_extent(inode, cur, NULL, 0);
5948		if (IS_ERR(path))
5949			return;
5950		ex = path[path->p_depth].p_ext;
5951		if (!ex) {
5952			ext4_free_ext_path(path);
5953			ext4_mark_inode_dirty(NULL, inode);
5954			return;
5955		}
5956		old_cur = cur;
5957		cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5958		if (cur <= old_cur)
5959			cur = old_cur + 1;
5960		ext4_ext_try_to_merge(NULL, inode, path, ex);
5961		down_write(&EXT4_I(inode)->i_data_sem);
5962		ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5963		up_write(&EXT4_I(inode)->i_data_sem);
5964		ext4_mark_inode_dirty(NULL, inode);
5965		ext4_free_ext_path(path);
5966	}
5967}
5968
5969/* Check if *cur is a hole and if it is, skip it */
5970static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
5971{
5972	int ret;
5973	struct ext4_map_blocks map;
5974
5975	map.m_lblk = *cur;
5976	map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
5977
5978	ret = ext4_map_blocks(NULL, inode, &map, 0);
5979	if (ret < 0)
5980		return ret;
5981	if (ret != 0)
5982		return 0;
5983	*cur = *cur + map.m_len;
5984	return 0;
5985}
5986
5987/* Count number of blocks used by this inode and update i_blocks */
5988int ext4_ext_replay_set_iblocks(struct inode *inode)
5989{
5990	struct ext4_ext_path *path = NULL, *path2 = NULL;
5991	struct ext4_extent *ex;
5992	ext4_lblk_t cur = 0, end;
5993	int numblks = 0, i, ret = 0;
5994	ext4_fsblk_t cmp1, cmp2;
5995	struct ext4_map_blocks map;
5996
5997	/* Determin the size of the file first */
5998	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5999					EXT4_EX_NOCACHE);
6000	if (IS_ERR(path))
6001		return PTR_ERR(path);
6002	ex = path[path->p_depth].p_ext;
6003	if (!ex) {
6004		ext4_free_ext_path(path);
6005		goto out;
6006	}
6007	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6008	ext4_free_ext_path(path);
6009
6010	/* Count the number of data blocks */
6011	cur = 0;
6012	while (cur < end) {
6013		map.m_lblk = cur;
6014		map.m_len = end - cur;
6015		ret = ext4_map_blocks(NULL, inode, &map, 0);
6016		if (ret < 0)
6017			break;
6018		if (ret > 0)
6019			numblks += ret;
6020		cur = cur + map.m_len;
6021	}
6022
6023	/*
6024	 * Count the number of extent tree blocks. We do it by looking up
6025	 * two successive extents and determining the difference between
6026	 * their paths. When path is different for 2 successive extents
6027	 * we compare the blocks in the path at each level and increment
6028	 * iblocks by total number of differences found.
6029	 */
6030	cur = 0;
6031	ret = skip_hole(inode, &cur);
6032	if (ret < 0)
6033		goto out;
6034	path = ext4_find_extent(inode, cur, NULL, 0);
6035	if (IS_ERR(path))
6036		goto out;
6037	numblks += path->p_depth;
6038	ext4_free_ext_path(path);
6039	while (cur < end) {
6040		path = ext4_find_extent(inode, cur, NULL, 0);
6041		if (IS_ERR(path))
6042			break;
6043		ex = path[path->p_depth].p_ext;
6044		if (!ex) {
6045			ext4_free_ext_path(path);
6046			return 0;
6047		}
6048		cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6049					ext4_ext_get_actual_len(ex));
6050		ret = skip_hole(inode, &cur);
6051		if (ret < 0) {
6052			ext4_free_ext_path(path);
6053			break;
6054		}
6055		path2 = ext4_find_extent(inode, cur, NULL, 0);
6056		if (IS_ERR(path2)) {
6057			ext4_free_ext_path(path);
6058			break;
6059		}
6060		for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6061			cmp1 = cmp2 = 0;
6062			if (i <= path->p_depth)
6063				cmp1 = path[i].p_bh ?
6064					path[i].p_bh->b_blocknr : 0;
6065			if (i <= path2->p_depth)
6066				cmp2 = path2[i].p_bh ?
6067					path2[i].p_bh->b_blocknr : 0;
6068			if (cmp1 != cmp2 && cmp2 != 0)
6069				numblks++;
6070		}
6071		ext4_free_ext_path(path);
6072		ext4_free_ext_path(path2);
6073	}
6074
6075out:
6076	inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6077	ext4_mark_inode_dirty(NULL, inode);
6078	return 0;
6079}
6080
6081int ext4_ext_clear_bb(struct inode *inode)
6082{
6083	struct ext4_ext_path *path = NULL;
6084	struct ext4_extent *ex;
6085	ext4_lblk_t cur = 0, end;
6086	int j, ret = 0;
6087	struct ext4_map_blocks map;
6088
6089	if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
6090		return 0;
6091
6092	/* Determin the size of the file first */
6093	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6094					EXT4_EX_NOCACHE);
6095	if (IS_ERR(path))
6096		return PTR_ERR(path);
6097	ex = path[path->p_depth].p_ext;
6098	if (!ex) {
6099		ext4_free_ext_path(path);
6100		return 0;
6101	}
6102	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6103	ext4_free_ext_path(path);
6104
6105	cur = 0;
6106	while (cur < end) {
6107		map.m_lblk = cur;
6108		map.m_len = end - cur;
6109		ret = ext4_map_blocks(NULL, inode, &map, 0);
6110		if (ret < 0)
6111			break;
6112		if (ret > 0) {
6113			path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
6114			if (!IS_ERR_OR_NULL(path)) {
6115				for (j = 0; j < path->p_depth; j++) {
6116
6117					ext4_mb_mark_bb(inode->i_sb,
6118							path[j].p_block, 1, false);
6119					ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6120							0, path[j].p_block, 1, 1);
6121				}
6122				ext4_free_ext_path(path);
6123			}
6124			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, false);
6125			ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6126					map.m_lblk, map.m_pblk, map.m_len, 1);
6127		}
6128		cur = cur + map.m_len;
6129	}
6130
6131	return 0;
6132}