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 struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
  88						  struct inode *inode,
  89						  struct ext4_ext_path *path,
  90						  ext4_lblk_t split,
  91						  int split_flag, int flags);
 
  92
  93static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)
  94{
  95	/*
  96	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
  97	 * moment, get_block can be called only for blocks inside i_size since
  98	 * page cache has been already dropped and writes are blocked by
  99	 * i_rwsem. So we can safely drop the i_data_sem here.
 100	 */
 101	BUG_ON(EXT4_JOURNAL(inode) == NULL);
 102	ext4_discard_preallocations(inode);
 103	up_write(&EXT4_I(inode)->i_data_sem);
 104	*dropped = 1;
 105	return 0;
 106}
 107
 108static inline void ext4_ext_path_brelse(struct ext4_ext_path *path)
 109{
 110	brelse(path->p_bh);
 111	path->p_bh = NULL;
 112}
 113
 114static void ext4_ext_drop_refs(struct ext4_ext_path *path)
 115{
 116	int depth, i;
 117
 118	if (IS_ERR_OR_NULL(path))
 119		return;
 120	depth = path->p_depth;
 121	for (i = 0; i <= depth; i++, path++)
 122		ext4_ext_path_brelse(path);
 123}
 124
 125void ext4_free_ext_path(struct ext4_ext_path *path)
 126{
 127	if (IS_ERR_OR_NULL(path))
 128		return;
 129	ext4_ext_drop_refs(path);
 130	kfree(path);
 131}
 132
 133/*
 134 * Make sure 'handle' has at least 'check_cred' credits. If not, restart
 135 * transaction with 'restart_cred' credits. The function drops i_data_sem
 136 * when restarting transaction and gets it after transaction is restarted.
 137 *
 138 * The function returns 0 on success, 1 if transaction had to be restarted,
 139 * and < 0 in case of fatal error.
 140 */
 141int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 142				int check_cred, int restart_cred,
 143				int revoke_cred)
 144{
 145	int ret;
 146	int dropped = 0;
 147
 148	ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
 149		revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
 150	if (dropped)
 151		down_write(&EXT4_I(inode)->i_data_sem);
 152	return ret;
 153}
 154
 155/*
 156 * could return:
 157 *  - EROFS
 158 *  - ENOMEM
 159 */
 160static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 161				struct ext4_ext_path *path)
 162{
 163	int err = 0;
 164
 165	if (path->p_bh) {
 166		/* path points to block */
 167		BUFFER_TRACE(path->p_bh, "get_write_access");
 168		err = ext4_journal_get_write_access(handle, inode->i_sb,
 169						    path->p_bh, EXT4_JTR_NONE);
 170		/*
 171		 * The extent buffer's verified bit will be set again in
 172		 * __ext4_ext_dirty(). We could leave an inconsistent
 173		 * buffer if the extents updating procudure break off du
 174		 * to some error happens, force to check it again.
 175		 */
 176		if (!err)
 177			clear_buffer_verified(path->p_bh);
 178	}
 179	/* path points to leaf/index in inode body */
 180	/* we use in-core data, no need to protect them */
 181	return err;
 182}
 183
 184/*
 185 * could return:
 186 *  - EROFS
 187 *  - ENOMEM
 188 *  - EIO
 189 */
 190static int __ext4_ext_dirty(const char *where, unsigned int line,
 191			    handle_t *handle, struct inode *inode,
 192			    struct ext4_ext_path *path)
 193{
 194	int err;
 195
 196	WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 197	if (path->p_bh) {
 198		ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 199		/* path points to block */
 200		err = __ext4_handle_dirty_metadata(where, line, handle,
 201						   inode, path->p_bh);
 202		/* Extents updating done, re-set verified flag */
 203		if (!err)
 204			set_buffer_verified(path->p_bh);
 205	} else {
 206		/* path points to leaf/index in inode body */
 207		err = ext4_mark_inode_dirty(handle, inode);
 208	}
 209	return err;
 210}
 211
 212#define ext4_ext_dirty(handle, inode, path) \
 213		__ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 214
 215static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 216			      struct ext4_ext_path *path,
 217			      ext4_lblk_t block)
 218{
 219	if (path) {
 220		int depth = path->p_depth;
 221		struct ext4_extent *ex;
 222
 223		/*
 224		 * Try to predict block placement assuming that we are
 225		 * filling in a file which will eventually be
 226		 * non-sparse --- i.e., in the case of libbfd writing
 227		 * an ELF object sections out-of-order but in a way
 228		 * the eventually results in a contiguous object or
 229		 * executable file, or some database extending a table
 230		 * space file.  However, this is actually somewhat
 231		 * non-ideal if we are writing a sparse file such as
 232		 * qemu or KVM writing a raw image file that is going
 233		 * to stay fairly sparse, since it will end up
 234		 * fragmenting the file system's free space.  Maybe we
 235		 * should have some hueristics or some way to allow
 236		 * userspace to pass a hint to file system,
 237		 * especially if the latter case turns out to be
 238		 * common.
 239		 */
 240		ex = path[depth].p_ext;
 241		if (ex) {
 242			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 243			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 244
 245			if (block > ext_block)
 246				return ext_pblk + (block - ext_block);
 247			else
 248				return ext_pblk - (ext_block - block);
 249		}
 250
 251		/* it looks like index is empty;
 252		 * try to find starting block from index itself */
 253		if (path[depth].p_bh)
 254			return path[depth].p_bh->b_blocknr;
 255	}
 256
 257	/* OK. use inode's group */
 258	return ext4_inode_to_goal_block(inode);
 259}
 260
 261/*
 262 * Allocation for a meta data block
 263 */
 264static ext4_fsblk_t
 265ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 266			struct ext4_ext_path *path,
 267			struct ext4_extent *ex, int *err, unsigned int flags)
 268{
 269	ext4_fsblk_t goal, newblock;
 270
 271	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 272	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 273					NULL, err);
 274	return newblock;
 275}
 276
 277static inline int ext4_ext_space_block(struct inode *inode, int check)
 278{
 279	int size;
 280
 281	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 282			/ sizeof(struct ext4_extent);
 283#ifdef AGGRESSIVE_TEST
 284	if (!check && size > 6)
 285		size = 6;
 286#endif
 287	return size;
 288}
 289
 290static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 291{
 292	int size;
 293
 294	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 295			/ sizeof(struct ext4_extent_idx);
 296#ifdef AGGRESSIVE_TEST
 297	if (!check && size > 5)
 298		size = 5;
 299#endif
 300	return size;
 301}
 302
 303static inline int ext4_ext_space_root(struct inode *inode, int check)
 304{
 305	int size;
 306
 307	size = sizeof(EXT4_I(inode)->i_data);
 308	size -= sizeof(struct ext4_extent_header);
 309	size /= sizeof(struct ext4_extent);
 310#ifdef AGGRESSIVE_TEST
 311	if (!check && size > 3)
 312		size = 3;
 313#endif
 314	return size;
 315}
 316
 317static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 318{
 319	int size;
 320
 321	size = sizeof(EXT4_I(inode)->i_data);
 322	size -= sizeof(struct ext4_extent_header);
 323	size /= sizeof(struct ext4_extent_idx);
 324#ifdef AGGRESSIVE_TEST
 325	if (!check && size > 4)
 326		size = 4;
 327#endif
 328	return size;
 329}
 330
 331static inline struct ext4_ext_path *
 332ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 333			   struct ext4_ext_path *path, ext4_lblk_t lblk,
 334			   int nofail)
 335{
 
 336	int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 337	int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;
 338
 339	if (nofail)
 340		flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;
 341
 342	return ext4_split_extent_at(handle, inode, path, lblk, unwritten ?
 343			EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 344			flags);
 345}
 346
 347static int
 348ext4_ext_max_entries(struct inode *inode, int depth)
 349{
 350	int max;
 351
 352	if (depth == ext_depth(inode)) {
 353		if (depth == 0)
 354			max = ext4_ext_space_root(inode, 1);
 355		else
 356			max = ext4_ext_space_root_idx(inode, 1);
 357	} else {
 358		if (depth == 0)
 359			max = ext4_ext_space_block(inode, 1);
 360		else
 361			max = ext4_ext_space_block_idx(inode, 1);
 362	}
 363
 364	return max;
 365}
 366
 367static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 368{
 369	ext4_fsblk_t block = ext4_ext_pblock(ext);
 370	int len = ext4_ext_get_actual_len(ext);
 371	ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 372
 373	/*
 374	 * We allow neither:
 375	 *  - zero length
 376	 *  - overflow/wrap-around
 377	 */
 378	if (lblock + len <= lblock)
 379		return 0;
 380	return ext4_inode_block_valid(inode, block, len);
 381}
 382
 383static int ext4_valid_extent_idx(struct inode *inode,
 384				struct ext4_extent_idx *ext_idx)
 385{
 386	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 387
 388	return ext4_inode_block_valid(inode, block, 1);
 389}
 390
 391static int ext4_valid_extent_entries(struct inode *inode,
 392				     struct ext4_extent_header *eh,
 393				     ext4_lblk_t lblk, ext4_fsblk_t *pblk,
 394				     int depth)
 395{
 396	unsigned short entries;
 397	ext4_lblk_t lblock = 0;
 398	ext4_lblk_t cur = 0;
 399
 400	if (eh->eh_entries == 0)
 401		return 1;
 402
 403	entries = le16_to_cpu(eh->eh_entries);
 404
 405	if (depth == 0) {
 406		/* leaf entries */
 407		struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 408
 409		/*
 410		 * The logical block in the first entry should equal to
 411		 * the number in the index block.
 412		 */
 413		if (depth != ext_depth(inode) &&
 414		    lblk != le32_to_cpu(ext->ee_block))
 415			return 0;
 416		while (entries) {
 417			if (!ext4_valid_extent(inode, ext))
 418				return 0;
 419
 420			/* Check for overlapping extents */
 421			lblock = le32_to_cpu(ext->ee_block);
 422			if (lblock < cur) {
 
 423				*pblk = ext4_ext_pblock(ext);
 424				return 0;
 425			}
 426			cur = lblock + ext4_ext_get_actual_len(ext);
 427			ext++;
 428			entries--;
 
 429		}
 430	} else {
 431		struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 432
 433		/*
 434		 * The logical block in the first entry should equal to
 435		 * the number in the parent index block.
 436		 */
 437		if (depth != ext_depth(inode) &&
 438		    lblk != le32_to_cpu(ext_idx->ei_block))
 439			return 0;
 440		while (entries) {
 441			if (!ext4_valid_extent_idx(inode, ext_idx))
 442				return 0;
 443
 444			/* Check for overlapping index extents */
 445			lblock = le32_to_cpu(ext_idx->ei_block);
 446			if (lblock < cur) {
 447				*pblk = ext4_idx_pblock(ext_idx);
 448				return 0;
 449			}
 450			ext_idx++;
 451			entries--;
 452			cur = lblock + 1;
 453		}
 454	}
 455	return 1;
 456}
 457
 458static int __ext4_ext_check(const char *function, unsigned int line,
 459			    struct inode *inode, struct ext4_extent_header *eh,
 460			    int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
 461{
 462	const char *error_msg;
 463	int max = 0, err = -EFSCORRUPTED;
 464
 465	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 466		error_msg = "invalid magic";
 467		goto corrupted;
 468	}
 469	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 470		error_msg = "unexpected eh_depth";
 471		goto corrupted;
 472	}
 473	if (unlikely(eh->eh_max == 0)) {
 474		error_msg = "invalid eh_max";
 475		goto corrupted;
 476	}
 477	max = ext4_ext_max_entries(inode, depth);
 478	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 479		error_msg = "too large eh_max";
 480		goto corrupted;
 481	}
 482	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 483		error_msg = "invalid eh_entries";
 484		goto corrupted;
 485	}
 486	if (unlikely((eh->eh_entries == 0) && (depth > 0))) {
 487		error_msg = "eh_entries is 0 but eh_depth is > 0";
 488		goto corrupted;
 489	}
 490	if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
 491		error_msg = "invalid extent entries";
 492		goto corrupted;
 493	}
 494	if (unlikely(depth > 32)) {
 495		error_msg = "too large eh_depth";
 496		goto corrupted;
 497	}
 498	/* Verify checksum on non-root extent tree nodes */
 499	if (ext_depth(inode) != depth &&
 500	    !ext4_extent_block_csum_verify(inode, eh)) {
 501		error_msg = "extent tree corrupted";
 502		err = -EFSBADCRC;
 503		goto corrupted;
 504	}
 505	return 0;
 506
 507corrupted:
 508	ext4_error_inode_err(inode, function, line, 0, -err,
 509			     "pblk %llu bad header/extent: %s - magic %x, "
 510			     "entries %u, max %u(%u), depth %u(%u)",
 511			     (unsigned long long) pblk, error_msg,
 512			     le16_to_cpu(eh->eh_magic),
 513			     le16_to_cpu(eh->eh_entries),
 514			     le16_to_cpu(eh->eh_max),
 515			     max, le16_to_cpu(eh->eh_depth), depth);
 516	return err;
 517}
 518
 519#define ext4_ext_check(inode, eh, depth, pblk)			\
 520	__ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
 521
 522int ext4_ext_check_inode(struct inode *inode)
 523{
 524	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 525}
 526
 527static void ext4_cache_extents(struct inode *inode,
 528			       struct ext4_extent_header *eh)
 529{
 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, lblk - prev, ~0,
 541					     EXTENT_STATUS_HOLE);
 542
 543		if (ext4_ext_is_unwritten(ex))
 544			status = EXTENT_STATUS_UNWRITTEN;
 545		ext4_es_cache_extent(inode, lblk, len,
 546				     ext4_ext_pblock(ex), status);
 547		prev = lblk + len;
 548	}
 549}
 550
 551static struct buffer_head *
 552__read_extent_tree_block(const char *function, unsigned int line,
 553			 struct inode *inode, struct ext4_extent_idx *idx,
 554			 int depth, int flags)
 555{
 556	struct buffer_head		*bh;
 557	int				err;
 558	gfp_t				gfp_flags = __GFP_MOVABLE | GFP_NOFS;
 559	ext4_fsblk_t			pblk;
 560
 561	if (flags & EXT4_EX_NOFAIL)
 562		gfp_flags |= __GFP_NOFAIL;
 563
 564	pblk = ext4_idx_pblock(idx);
 565	bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
 566	if (unlikely(!bh))
 567		return ERR_PTR(-ENOMEM);
 568
 569	if (!bh_uptodate_or_lock(bh)) {
 570		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 571		err = ext4_read_bh(bh, 0, NULL, false);
 572		if (err < 0)
 573			goto errout;
 574	}
 575	if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 576		return bh;
 577	err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
 578			       depth, pblk, le32_to_cpu(idx->ei_block));
 579	if (err)
 580		goto errout;
 581	set_buffer_verified(bh);
 582	/*
 583	 * If this is a leaf block, cache all of its entries
 584	 */
 585	if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 586		struct ext4_extent_header *eh = ext_block_hdr(bh);
 587		ext4_cache_extents(inode, eh);
 588	}
 589	return bh;
 590errout:
 591	put_bh(bh);
 592	return ERR_PTR(err);
 593
 594}
 595
 596#define read_extent_tree_block(inode, idx, depth, flags)		\
 597	__read_extent_tree_block(__func__, __LINE__, (inode), (idx),	\
 598				 (depth), (flags))
 599
 600/*
 601 * This function is called to cache a file's extent information in the
 602 * extent status tree
 603 */
 604int ext4_ext_precache(struct inode *inode)
 605{
 606	struct ext4_inode_info *ei = EXT4_I(inode);
 607	struct ext4_ext_path *path = NULL;
 608	struct buffer_head *bh;
 609	int i = 0, depth, ret = 0;
 610
 611	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 612		return 0;	/* not an extent-mapped inode */
 613
 614	down_read(&ei->i_data_sem);
 615	depth = ext_depth(inode);
 616
 617	/* Don't cache anything if there are no external extent blocks */
 618	if (!depth) {
 619		up_read(&ei->i_data_sem);
 620		return ret;
 621	}
 622
 623	path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 624		       GFP_NOFS);
 625	if (path == NULL) {
 626		up_read(&ei->i_data_sem);
 627		return -ENOMEM;
 628	}
 629
 630	path[0].p_hdr = ext_inode_hdr(inode);
 631	ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 632	if (ret)
 633		goto out;
 634	path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 635	while (i >= 0) {
 636		/*
 637		 * If this is a leaf block or we've reached the end of
 638		 * the index block, go up
 639		 */
 640		if ((i == depth) ||
 641		    path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 642			ext4_ext_path_brelse(path + i);
 
 643			i--;
 644			continue;
 645		}
 646		bh = read_extent_tree_block(inode, path[i].p_idx++,
 
 647					    depth - i - 1,
 648					    EXT4_EX_FORCE_CACHE);
 649		if (IS_ERR(bh)) {
 650			ret = PTR_ERR(bh);
 651			break;
 652		}
 653		i++;
 654		path[i].p_bh = bh;
 655		path[i].p_hdr = ext_block_hdr(bh);
 656		path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 657	}
 658	ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 659out:
 660	up_read(&ei->i_data_sem);
 661	ext4_free_ext_path(path);
 
 662	return ret;
 663}
 664
 665#ifdef EXT_DEBUG
 666static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 667{
 668	int k, l = path->p_depth;
 669
 670	ext_debug(inode, "path:");
 671	for (k = 0; k <= l; k++, path++) {
 672		if (path->p_idx) {
 673			ext_debug(inode, "  %d->%llu",
 674				  le32_to_cpu(path->p_idx->ei_block),
 675				  ext4_idx_pblock(path->p_idx));
 676		} else if (path->p_ext) {
 677			ext_debug(inode, "  %d:[%d]%d:%llu ",
 678				  le32_to_cpu(path->p_ext->ee_block),
 679				  ext4_ext_is_unwritten(path->p_ext),
 680				  ext4_ext_get_actual_len(path->p_ext),
 681				  ext4_ext_pblock(path->p_ext));
 682		} else
 683			ext_debug(inode, "  []");
 684	}
 685	ext_debug(inode, "\n");
 686}
 687
 688static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 689{
 690	int depth = ext_depth(inode);
 691	struct ext4_extent_header *eh;
 692	struct ext4_extent *ex;
 693	int i;
 694
 695	if (IS_ERR_OR_NULL(path))
 696		return;
 697
 698	eh = path[depth].p_hdr;
 699	ex = EXT_FIRST_EXTENT(eh);
 700
 701	ext_debug(inode, "Displaying leaf extents\n");
 702
 703	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 704		ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 705			  ext4_ext_is_unwritten(ex),
 706			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 707	}
 708	ext_debug(inode, "\n");
 709}
 710
 711static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 712			ext4_fsblk_t newblock, int level)
 713{
 714	int depth = ext_depth(inode);
 715	struct ext4_extent *ex;
 716
 717	if (depth != level) {
 718		struct ext4_extent_idx *idx;
 719		idx = path[level].p_idx;
 720		while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 721			ext_debug(inode, "%d: move %d:%llu in new index %llu\n",
 722				  level, le32_to_cpu(idx->ei_block),
 723				  ext4_idx_pblock(idx), newblock);
 724			idx++;
 725		}
 726
 727		return;
 728	}
 729
 730	ex = path[depth].p_ext;
 731	while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 732		ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",
 733				le32_to_cpu(ex->ee_block),
 734				ext4_ext_pblock(ex),
 735				ext4_ext_is_unwritten(ex),
 736				ext4_ext_get_actual_len(ex),
 737				newblock);
 738		ex++;
 739	}
 740}
 741
 742#else
 743#define ext4_ext_show_path(inode, path)
 744#define ext4_ext_show_leaf(inode, path)
 745#define ext4_ext_show_move(inode, path, newblock, level)
 746#endif
 747
 
 
 
 
 
 
 
 
 
 
 
 
 
 748/*
 749 * ext4_ext_binsearch_idx:
 750 * binary search for the closest index of the given block
 751 * the header must be checked before calling this
 752 */
 753static void
 754ext4_ext_binsearch_idx(struct inode *inode,
 755			struct ext4_ext_path *path, ext4_lblk_t block)
 756{
 757	struct ext4_extent_header *eh = path->p_hdr;
 758	struct ext4_extent_idx *r, *l, *m;
 759
 760
 761	ext_debug(inode, "binsearch for %u(idx):  ", block);
 762
 763	l = EXT_FIRST_INDEX(eh) + 1;
 764	r = EXT_LAST_INDEX(eh);
 765	while (l <= r) {
 766		m = l + (r - l) / 2;
 767		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 768			  le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),
 769			  r, le32_to_cpu(r->ei_block));
 770
 771		if (block < le32_to_cpu(m->ei_block))
 772			r = m - 1;
 773		else
 774			l = m + 1;
 
 
 
 775	}
 776
 777	path->p_idx = l - 1;
 778	ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 779		  ext4_idx_pblock(path->p_idx));
 780
 781#ifdef CHECK_BINSEARCH
 782	{
 783		struct ext4_extent_idx *chix, *ix;
 784		int k;
 785
 786		chix = ix = EXT_FIRST_INDEX(eh);
 787		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 788			if (k != 0 && le32_to_cpu(ix->ei_block) <=
 789			    le32_to_cpu(ix[-1].ei_block)) {
 790				printk(KERN_DEBUG "k=%d, ix=0x%p, "
 791				       "first=0x%p\n", k,
 792				       ix, EXT_FIRST_INDEX(eh));
 793				printk(KERN_DEBUG "%u <= %u\n",
 794				       le32_to_cpu(ix->ei_block),
 795				       le32_to_cpu(ix[-1].ei_block));
 796			}
 797			BUG_ON(k && le32_to_cpu(ix->ei_block)
 798					   <= le32_to_cpu(ix[-1].ei_block));
 799			if (block < le32_to_cpu(ix->ei_block))
 800				break;
 801			chix = ix;
 802		}
 803		BUG_ON(chix != path->p_idx);
 804	}
 805#endif
 806
 807}
 808
 809/*
 810 * ext4_ext_binsearch:
 811 * binary search for closest extent of the given block
 812 * the header must be checked before calling this
 813 */
 814static void
 815ext4_ext_binsearch(struct inode *inode,
 816		struct ext4_ext_path *path, ext4_lblk_t block)
 817{
 818	struct ext4_extent_header *eh = path->p_hdr;
 819	struct ext4_extent *r, *l, *m;
 820
 821	if (eh->eh_entries == 0) {
 822		/*
 823		 * this leaf is empty:
 824		 * we get such a leaf in split/add case
 825		 */
 826		return;
 827	}
 828
 829	ext_debug(inode, "binsearch for %u:  ", block);
 830
 831	l = EXT_FIRST_EXTENT(eh) + 1;
 832	r = EXT_LAST_EXTENT(eh);
 833
 834	while (l <= r) {
 835		m = l + (r - l) / 2;
 836		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,
 837			  le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),
 838			  r, le32_to_cpu(r->ee_block));
 839
 840		if (block < le32_to_cpu(m->ee_block))
 841			r = m - 1;
 842		else
 843			l = m + 1;
 
 
 
 844	}
 845
 846	path->p_ext = l - 1;
 847	ext_debug(inode, "  -> %d:%llu:[%d]%d ",
 848			le32_to_cpu(path->p_ext->ee_block),
 849			ext4_ext_pblock(path->p_ext),
 850			ext4_ext_is_unwritten(path->p_ext),
 851			ext4_ext_get_actual_len(path->p_ext));
 852
 853#ifdef CHECK_BINSEARCH
 854	{
 855		struct ext4_extent *chex, *ex;
 856		int k;
 857
 858		chex = ex = EXT_FIRST_EXTENT(eh);
 859		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 860			BUG_ON(k && le32_to_cpu(ex->ee_block)
 861					  <= le32_to_cpu(ex[-1].ee_block));
 862			if (block < le32_to_cpu(ex->ee_block))
 863				break;
 864			chex = ex;
 865		}
 866		BUG_ON(chex != path->p_ext);
 867	}
 868#endif
 869
 870}
 871
 872void ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 873{
 874	struct ext4_extent_header *eh;
 875
 876	eh = ext_inode_hdr(inode);
 877	eh->eh_depth = 0;
 878	eh->eh_entries = 0;
 879	eh->eh_magic = EXT4_EXT_MAGIC;
 880	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 881	eh->eh_generation = 0;
 882	ext4_mark_inode_dirty(handle, inode);
 883}
 884
 885struct ext4_ext_path *
 886ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 887		 struct ext4_ext_path *path, int flags)
 888{
 889	struct ext4_extent_header *eh;
 890	struct buffer_head *bh;
 
 891	short int depth, i, ppos = 0;
 892	int ret;
 893	gfp_t gfp_flags = GFP_NOFS;
 894
 895	if (flags & EXT4_EX_NOFAIL)
 896		gfp_flags |= __GFP_NOFAIL;
 897
 898	eh = ext_inode_hdr(inode);
 899	depth = ext_depth(inode);
 900	if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 901		EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 902				 depth);
 903		ret = -EFSCORRUPTED;
 904		goto err;
 905	}
 906
 907	if (path) {
 908		ext4_ext_drop_refs(path);
 909		if (depth > path[0].p_maxdepth) {
 910			kfree(path);
 911			path = NULL;
 912		}
 913	}
 914	if (!path) {
 915		/* account possible depth increase */
 916		path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 917				gfp_flags);
 918		if (unlikely(!path))
 919			return ERR_PTR(-ENOMEM);
 920		path[0].p_maxdepth = depth + 1;
 921	}
 922	path[0].p_hdr = eh;
 923	path[0].p_bh = NULL;
 924
 925	i = depth;
 926	if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
 927		ext4_cache_extents(inode, eh);
 928	/* walk through the tree */
 929	while (i) {
 930		ext_debug(inode, "depth %d: num %d, max %d\n",
 931			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 932
 933		ext4_ext_binsearch_idx(inode, path + ppos, block);
 934		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 935		path[ppos].p_depth = i;
 936		path[ppos].p_ext = NULL;
 937
 938		bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
 
 939		if (IS_ERR(bh)) {
 940			ret = PTR_ERR(bh);
 941			goto err;
 942		}
 943
 944		eh = ext_block_hdr(bh);
 945		ppos++;
 946		path[ppos].p_bh = bh;
 947		path[ppos].p_hdr = eh;
 948	}
 949
 950	path[ppos].p_depth = i;
 951	path[ppos].p_ext = NULL;
 952	path[ppos].p_idx = NULL;
 953
 954	/* find extent */
 955	ext4_ext_binsearch(inode, path + ppos, block);
 956	/* if not an empty leaf */
 957	if (path[ppos].p_ext)
 958		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 959
 960	ext4_ext_show_path(inode, path);
 961
 962	return path;
 963
 964err:
 965	ext4_free_ext_path(path);
 
 
 
 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 struct ext4_ext_path *
1399ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1400			 unsigned int mb_flags, unsigned int gb_flags,
1401			 struct ext4_ext_path *path,
1402			 struct ext4_extent *newext)
1403{
 
1404	struct ext4_ext_path *curp;
1405	int depth, i, err = 0;
1406	ext4_lblk_t ee_block = le32_to_cpu(newext->ee_block);
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 errout;
1426
1427		/* refill path */
1428		path = ext4_find_extent(inode, ee_block, path, gb_flags);
1429		return path;
1430	}
1431
1432	/* tree is full, time to grow in depth */
1433	err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1434	if (err)
1435		goto errout;
 
 
1436
1437	/* refill path */
1438	path = ext4_find_extent(inode, ee_block, path, gb_flags);
1439	if (IS_ERR(path))
1440		return path;
 
 
 
 
1441
1442	/*
1443	 * only first (depth 0 -> 1) produces free space;
1444	 * in all other cases we have to split the grown tree
1445	 */
1446	depth = ext_depth(inode);
1447	if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1448		/* now we need to split */
1449		goto repeat;
 
1450	}
1451
1452	return path;
1453
1454errout:
1455	ext4_free_ext_path(path);
1456	return ERR_PTR(err);
1457}
1458
1459/*
1460 * search the closest allocated block to the left for *logical
1461 * and returns it at @logical + it's physical address at @phys
1462 * if *logical is the smallest allocated block, the function
1463 * returns 0 at @phys
1464 * return value contains 0 (success) or error code
1465 */
1466static int ext4_ext_search_left(struct inode *inode,
1467				struct ext4_ext_path *path,
1468				ext4_lblk_t *logical, ext4_fsblk_t *phys)
1469{
1470	struct ext4_extent_idx *ix;
1471	struct ext4_extent *ex;
1472	int depth, ee_len;
1473
1474	if (unlikely(path == NULL)) {
1475		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1476		return -EFSCORRUPTED;
1477	}
1478	depth = path->p_depth;
1479	*phys = 0;
1480
1481	if (depth == 0 && path->p_ext == NULL)
1482		return 0;
1483
1484	/* usually extent in the path covers blocks smaller
1485	 * then *logical, but it can be that extent is the
1486	 * first one in the file */
1487
1488	ex = path[depth].p_ext;
1489	ee_len = ext4_ext_get_actual_len(ex);
1490	if (*logical < le32_to_cpu(ex->ee_block)) {
1491		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1492			EXT4_ERROR_INODE(inode,
1493					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1494					 *logical, le32_to_cpu(ex->ee_block));
1495			return -EFSCORRUPTED;
1496		}
1497		while (--depth >= 0) {
1498			ix = path[depth].p_idx;
1499			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1500				EXT4_ERROR_INODE(inode,
1501				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1502				  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1503				  le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),
 
1504				  depth);
1505				return -EFSCORRUPTED;
1506			}
1507		}
1508		return 0;
1509	}
1510
1511	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1512		EXT4_ERROR_INODE(inode,
1513				 "logical %d < ee_block %d + ee_len %d!",
1514				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1515		return -EFSCORRUPTED;
1516	}
1517
1518	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1519	*phys = ext4_ext_pblock(ex) + ee_len - 1;
1520	return 0;
1521}
1522
1523/*
1524 * Search the closest allocated block to the right for *logical
1525 * and returns it at @logical + it's physical address at @phys.
1526 * If not exists, return 0 and @phys is set to 0. We will return
1527 * 1 which means we found an allocated block and ret_ex is valid.
1528 * Or return a (< 0) error code.
1529 */
1530static int ext4_ext_search_right(struct inode *inode,
1531				 struct ext4_ext_path *path,
1532				 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1533				 struct ext4_extent *ret_ex)
1534{
1535	struct buffer_head *bh = NULL;
1536	struct ext4_extent_header *eh;
1537	struct ext4_extent_idx *ix;
1538	struct ext4_extent *ex;
 
1539	int depth;	/* Note, NOT eh_depth; depth from top of tree */
1540	int ee_len;
1541
1542	if (unlikely(path == NULL)) {
1543		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1544		return -EFSCORRUPTED;
1545	}
1546	depth = path->p_depth;
1547	*phys = 0;
1548
1549	if (depth == 0 && path->p_ext == NULL)
1550		return 0;
1551
1552	/* usually extent in the path covers blocks smaller
1553	 * then *logical, but it can be that extent is the
1554	 * first one in the file */
1555
1556	ex = path[depth].p_ext;
1557	ee_len = ext4_ext_get_actual_len(ex);
1558	if (*logical < le32_to_cpu(ex->ee_block)) {
1559		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1560			EXT4_ERROR_INODE(inode,
1561					 "first_extent(path[%d].p_hdr) != ex",
1562					 depth);
1563			return -EFSCORRUPTED;
1564		}
1565		while (--depth >= 0) {
1566			ix = path[depth].p_idx;
1567			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1568				EXT4_ERROR_INODE(inode,
1569						 "ix != EXT_FIRST_INDEX *logical %d!",
1570						 *logical);
1571				return -EFSCORRUPTED;
1572			}
1573		}
1574		goto found_extent;
1575	}
1576
1577	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1578		EXT4_ERROR_INODE(inode,
1579				 "logical %d < ee_block %d + ee_len %d!",
1580				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1581		return -EFSCORRUPTED;
1582	}
1583
1584	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1585		/* next allocated block in this leaf */
1586		ex++;
1587		goto found_extent;
1588	}
1589
1590	/* go up and search for index to the right */
1591	while (--depth >= 0) {
1592		ix = path[depth].p_idx;
1593		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1594			goto got_index;
1595	}
1596
1597	/* we've gone up to the root and found no index to the right */
1598	return 0;
1599
1600got_index:
1601	/* we've found index to the right, let's
1602	 * follow it and find the closest allocated
1603	 * block to the right */
1604	ix++;
 
1605	while (++depth < path->p_depth) {
1606		/* subtract from p_depth to get proper eh_depth */
1607		bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
 
1608		if (IS_ERR(bh))
1609			return PTR_ERR(bh);
1610		eh = ext_block_hdr(bh);
1611		ix = EXT_FIRST_INDEX(eh);
 
1612		put_bh(bh);
1613	}
1614
1615	bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
1616	if (IS_ERR(bh))
1617		return PTR_ERR(bh);
1618	eh = ext_block_hdr(bh);
1619	ex = EXT_FIRST_EXTENT(eh);
1620found_extent:
1621	*logical = le32_to_cpu(ex->ee_block);
1622	*phys = ext4_ext_pblock(ex);
1623	if (ret_ex)
1624		*ret_ex = *ex;
1625	if (bh)
1626		put_bh(bh);
1627	return 1;
1628}
1629
1630/*
1631 * ext4_ext_next_allocated_block:
1632 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1633 * NOTE: it considers block number from index entry as
1634 * allocated block. Thus, index entries have to be consistent
1635 * with leaves.
1636 */
1637ext4_lblk_t
1638ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1639{
1640	int depth;
1641
1642	BUG_ON(path == NULL);
1643	depth = path->p_depth;
1644
1645	if (depth == 0 && path->p_ext == NULL)
1646		return EXT_MAX_BLOCKS;
1647
1648	while (depth >= 0) {
1649		struct ext4_ext_path *p = &path[depth];
1650
1651		if (depth == path->p_depth) {
1652			/* leaf */
1653			if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))
1654				return le32_to_cpu(p->p_ext[1].ee_block);
1655		} else {
1656			/* index */
1657			if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))
1658				return le32_to_cpu(p->p_idx[1].ei_block);
1659		}
1660		depth--;
1661	}
1662
1663	return EXT_MAX_BLOCKS;
1664}
1665
1666/*
1667 * ext4_ext_next_leaf_block:
1668 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1669 */
1670static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1671{
1672	int depth;
1673
1674	BUG_ON(path == NULL);
1675	depth = path->p_depth;
1676
1677	/* zero-tree has no leaf blocks at all */
1678	if (depth == 0)
1679		return EXT_MAX_BLOCKS;
1680
1681	/* go to index block */
1682	depth--;
1683
1684	while (depth >= 0) {
1685		if (path[depth].p_idx !=
1686				EXT_LAST_INDEX(path[depth].p_hdr))
1687			return (ext4_lblk_t)
1688				le32_to_cpu(path[depth].p_idx[1].ei_block);
1689		depth--;
1690	}
1691
1692	return EXT_MAX_BLOCKS;
1693}
1694
1695/*
1696 * ext4_ext_correct_indexes:
1697 * if leaf gets modified and modified extent is first in the leaf,
1698 * then we have to correct all indexes above.
1699 * TODO: do we need to correct tree in all cases?
1700 */
1701static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1702				struct ext4_ext_path *path)
1703{
1704	struct ext4_extent_header *eh;
1705	int depth = ext_depth(inode);
1706	struct ext4_extent *ex;
1707	__le32 border;
1708	int k, err = 0;
1709
1710	eh = path[depth].p_hdr;
1711	ex = path[depth].p_ext;
1712
1713	if (unlikely(ex == NULL || eh == NULL)) {
1714		EXT4_ERROR_INODE(inode,
1715				 "ex %p == NULL or eh %p == NULL", ex, eh);
1716		return -EFSCORRUPTED;
1717	}
1718
1719	if (depth == 0) {
1720		/* there is no tree at all */
1721		return 0;
1722	}
1723
1724	if (ex != EXT_FIRST_EXTENT(eh)) {
1725		/* we correct tree if first leaf got modified only */
1726		return 0;
1727	}
1728
1729	/*
1730	 * TODO: we need correction if border is smaller than current one
1731	 */
1732	k = depth - 1;
1733	border = path[depth].p_ext->ee_block;
1734	err = ext4_ext_get_access(handle, inode, path + k);
1735	if (err)
1736		return err;
1737	path[k].p_idx->ei_block = border;
1738	err = ext4_ext_dirty(handle, inode, path + k);
1739	if (err)
1740		return err;
1741
1742	while (k--) {
1743		/* change all left-side indexes */
1744		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1745			break;
1746		err = ext4_ext_get_access(handle, inode, path + k);
1747		if (err)
1748			goto clean;
1749		path[k].p_idx->ei_block = border;
1750		err = ext4_ext_dirty(handle, inode, path + k);
1751		if (err)
1752			goto clean;
1753	}
1754	return 0;
1755
1756clean:
1757	/*
1758	 * The path[k].p_bh is either unmodified or with no verified bit
1759	 * set (see ext4_ext_get_access()). So just clear the verified bit
1760	 * of the successfully modified extents buffers, which will force
1761	 * these extents to be checked to avoid using inconsistent data.
1762	 */
1763	while (++k < depth)
1764		clear_buffer_verified(path[k].p_bh);
1765
1766	return err;
1767}
1768
1769static int ext4_can_extents_be_merged(struct inode *inode,
1770				      struct ext4_extent *ex1,
1771				      struct ext4_extent *ex2)
1772{
1773	unsigned short ext1_ee_len, ext2_ee_len;
1774
1775	if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1776		return 0;
1777
1778	ext1_ee_len = ext4_ext_get_actual_len(ex1);
1779	ext2_ee_len = ext4_ext_get_actual_len(ex2);
1780
1781	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1782			le32_to_cpu(ex2->ee_block))
1783		return 0;
1784
1785	if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1786		return 0;
1787
1788	if (ext4_ext_is_unwritten(ex1) &&
1789	    ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1790		return 0;
1791#ifdef AGGRESSIVE_TEST
1792	if (ext1_ee_len >= 4)
1793		return 0;
1794#endif
1795
1796	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1797		return 1;
1798	return 0;
1799}
1800
1801/*
1802 * This function tries to merge the "ex" extent to the next extent in the tree.
1803 * It always tries to merge towards right. If you want to merge towards
1804 * left, pass "ex - 1" as argument instead of "ex".
1805 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1806 * 1 if they got merged.
1807 */
1808static int ext4_ext_try_to_merge_right(struct inode *inode,
1809				 struct ext4_ext_path *path,
1810				 struct ext4_extent *ex)
1811{
1812	struct ext4_extent_header *eh;
1813	unsigned int depth, len;
1814	int merge_done = 0, unwritten;
1815
1816	depth = ext_depth(inode);
1817	BUG_ON(path[depth].p_hdr == NULL);
1818	eh = path[depth].p_hdr;
1819
1820	while (ex < EXT_LAST_EXTENT(eh)) {
1821		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1822			break;
1823		/* merge with next extent! */
1824		unwritten = ext4_ext_is_unwritten(ex);
1825		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1826				+ ext4_ext_get_actual_len(ex + 1));
1827		if (unwritten)
1828			ext4_ext_mark_unwritten(ex);
1829
1830		if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1831			len = (EXT_LAST_EXTENT(eh) - ex - 1)
1832				* sizeof(struct ext4_extent);
1833			memmove(ex + 1, ex + 2, len);
1834		}
1835		le16_add_cpu(&eh->eh_entries, -1);
1836		merge_done = 1;
1837		WARN_ON(eh->eh_entries == 0);
1838		if (!eh->eh_entries)
1839			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1840	}
1841
1842	return merge_done;
1843}
1844
1845/*
1846 * This function does a very simple check to see if we can collapse
1847 * an extent tree with a single extent tree leaf block into the inode.
1848 */
1849static void ext4_ext_try_to_merge_up(handle_t *handle,
1850				     struct inode *inode,
1851				     struct ext4_ext_path *path)
1852{
1853	size_t s;
1854	unsigned max_root = ext4_ext_space_root(inode, 0);
1855	ext4_fsblk_t blk;
1856
1857	if ((path[0].p_depth != 1) ||
1858	    (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1859	    (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1860		return;
1861
1862	/*
1863	 * We need to modify the block allocation bitmap and the block
1864	 * group descriptor to release the extent tree block.  If we
1865	 * can't get the journal credits, give up.
1866	 */
1867	if (ext4_journal_extend(handle, 2,
1868			ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1869		return;
1870
1871	/*
1872	 * Copy the extent data up to the inode
1873	 */
1874	blk = ext4_idx_pblock(path[0].p_idx);
1875	s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1876		sizeof(struct ext4_extent_idx);
1877	s += sizeof(struct ext4_extent_header);
1878
1879	path[1].p_maxdepth = path[0].p_maxdepth;
1880	memcpy(path[0].p_hdr, path[1].p_hdr, s);
1881	path[0].p_depth = 0;
1882	path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1883		(path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1884	path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1885
1886	ext4_ext_path_brelse(path + 1);
1887	ext4_free_blocks(handle, inode, NULL, blk, 1,
1888			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1889}
1890
1891/*
1892 * This function tries to merge the @ex extent to neighbours in the tree, then
1893 * tries to collapse the extent tree into the inode.
1894 */
1895static void ext4_ext_try_to_merge(handle_t *handle,
1896				  struct inode *inode,
1897				  struct ext4_ext_path *path,
1898				  struct ext4_extent *ex)
1899{
1900	struct ext4_extent_header *eh;
1901	unsigned int depth;
1902	int merge_done = 0;
1903
1904	depth = ext_depth(inode);
1905	BUG_ON(path[depth].p_hdr == NULL);
1906	eh = path[depth].p_hdr;
1907
1908	if (ex > EXT_FIRST_EXTENT(eh))
1909		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1910
1911	if (!merge_done)
1912		(void) ext4_ext_try_to_merge_right(inode, path, ex);
1913
1914	ext4_ext_try_to_merge_up(handle, inode, path);
1915}
1916
1917/*
1918 * check if a portion of the "newext" extent overlaps with an
1919 * existing extent.
1920 *
1921 * If there is an overlap discovered, it updates the length of the newext
1922 * such that there will be no overlap, and then returns 1.
1923 * If there is no overlap found, it returns 0.
1924 */
1925static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1926					   struct inode *inode,
1927					   struct ext4_extent *newext,
1928					   struct ext4_ext_path *path)
1929{
1930	ext4_lblk_t b1, b2;
1931	unsigned int depth, len1;
1932	unsigned int ret = 0;
1933
1934	b1 = le32_to_cpu(newext->ee_block);
1935	len1 = ext4_ext_get_actual_len(newext);
1936	depth = ext_depth(inode);
1937	if (!path[depth].p_ext)
1938		goto out;
1939	b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1940
1941	/*
1942	 * get the next allocated block if the extent in the path
1943	 * is before the requested block(s)
1944	 */
1945	if (b2 < b1) {
1946		b2 = ext4_ext_next_allocated_block(path);
1947		if (b2 == EXT_MAX_BLOCKS)
1948			goto out;
1949		b2 = EXT4_LBLK_CMASK(sbi, b2);
1950	}
1951
1952	/* check for wrap through zero on extent logical start block*/
1953	if (b1 + len1 < b1) {
1954		len1 = EXT_MAX_BLOCKS - b1;
1955		newext->ee_len = cpu_to_le16(len1);
1956		ret = 1;
1957	}
1958
1959	/* check for overlap */
1960	if (b1 + len1 > b2) {
1961		newext->ee_len = cpu_to_le16(b2 - b1);
1962		ret = 1;
1963	}
1964out:
1965	return ret;
1966}
1967
1968/*
1969 * ext4_ext_insert_extent:
1970 * tries to merge requested extent into the existing extent or
1971 * inserts requested extent as new one into the tree,
1972 * creating new leaf in the no-space case.
1973 */
1974struct ext4_ext_path *
1975ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1976		       struct ext4_ext_path *path,
1977		       struct ext4_extent *newext, int gb_flags)
1978{
 
1979	struct ext4_extent_header *eh;
1980	struct ext4_extent *ex, *fex;
1981	struct ext4_extent *nearex; /* nearest extent */
1982	int depth, len, err = 0;
 
1983	ext4_lblk_t next;
1984	int mb_flags = 0, unwritten;
1985
1986	if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1987		mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1988	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1989		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1990		err = -EFSCORRUPTED;
1991		goto errout;
1992	}
1993	depth = ext_depth(inode);
1994	ex = path[depth].p_ext;
1995	eh = path[depth].p_hdr;
1996	if (unlikely(path[depth].p_hdr == NULL)) {
1997		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1998		err = -EFSCORRUPTED;
1999		goto errout;
2000	}
2001
2002	/* try to insert block into found extent and return */
2003	if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
2004
2005		/*
2006		 * Try to see whether we should rather test the extent on
2007		 * right from ex, or from the left of ex. This is because
2008		 * ext4_find_extent() can return either extent on the
2009		 * left, or on the right from the searched position. This
2010		 * will make merging more effective.
2011		 */
2012		if (ex < EXT_LAST_EXTENT(eh) &&
2013		    (le32_to_cpu(ex->ee_block) +
2014		    ext4_ext_get_actual_len(ex) <
2015		    le32_to_cpu(newext->ee_block))) {
2016			ex += 1;
2017			goto prepend;
2018		} else if ((ex > EXT_FIRST_EXTENT(eh)) &&
2019			   (le32_to_cpu(newext->ee_block) +
2020			   ext4_ext_get_actual_len(newext) <
2021			   le32_to_cpu(ex->ee_block)))
2022			ex -= 1;
2023
2024		/* Try to append newex to the ex */
2025		if (ext4_can_extents_be_merged(inode, ex, newext)) {
2026			ext_debug(inode, "append [%d]%d block to %u:[%d]%d"
2027				  "(from %llu)\n",
2028				  ext4_ext_is_unwritten(newext),
2029				  ext4_ext_get_actual_len(newext),
2030				  le32_to_cpu(ex->ee_block),
2031				  ext4_ext_is_unwritten(ex),
2032				  ext4_ext_get_actual_len(ex),
2033				  ext4_ext_pblock(ex));
2034			err = ext4_ext_get_access(handle, inode,
2035						  path + depth);
2036			if (err)
2037				goto errout;
2038			unwritten = ext4_ext_is_unwritten(ex);
2039			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2040					+ ext4_ext_get_actual_len(newext));
2041			if (unwritten)
2042				ext4_ext_mark_unwritten(ex);
 
2043			nearex = ex;
2044			goto merge;
2045		}
2046
2047prepend:
2048		/* Try to prepend newex to the ex */
2049		if (ext4_can_extents_be_merged(inode, newext, ex)) {
2050			ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"
2051				  "(from %llu)\n",
2052				  le32_to_cpu(newext->ee_block),
2053				  ext4_ext_is_unwritten(newext),
2054				  ext4_ext_get_actual_len(newext),
2055				  le32_to_cpu(ex->ee_block),
2056				  ext4_ext_is_unwritten(ex),
2057				  ext4_ext_get_actual_len(ex),
2058				  ext4_ext_pblock(ex));
2059			err = ext4_ext_get_access(handle, inode,
2060						  path + depth);
2061			if (err)
2062				goto errout;
2063
2064			unwritten = ext4_ext_is_unwritten(ex);
2065			ex->ee_block = newext->ee_block;
2066			ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2067			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2068					+ ext4_ext_get_actual_len(newext));
2069			if (unwritten)
2070				ext4_ext_mark_unwritten(ex);
 
2071			nearex = ex;
2072			goto merge;
2073		}
2074	}
2075
2076	depth = ext_depth(inode);
2077	eh = path[depth].p_hdr;
2078	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2079		goto has_space;
2080
2081	/* probably next leaf has space for us? */
2082	fex = EXT_LAST_EXTENT(eh);
2083	next = EXT_MAX_BLOCKS;
2084	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2085		next = ext4_ext_next_leaf_block(path);
2086	if (next != EXT_MAX_BLOCKS) {
2087		struct ext4_ext_path *npath;
2088
2089		ext_debug(inode, "next leaf block - %u\n", next);
 
2090		npath = ext4_find_extent(inode, next, NULL, gb_flags);
2091		if (IS_ERR(npath)) {
2092			err = PTR_ERR(npath);
2093			goto errout;
2094		}
2095		BUG_ON(npath->p_depth != path->p_depth);
2096		eh = npath[depth].p_hdr;
2097		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2098			ext_debug(inode, "next leaf isn't full(%d)\n",
2099				  le16_to_cpu(eh->eh_entries));
2100			ext4_free_ext_path(path);
2101			path = npath;
2102			goto has_space;
2103		}
2104		ext_debug(inode, "next leaf has no free space(%d,%d)\n",
2105			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2106		ext4_free_ext_path(npath);
2107	}
2108
2109	/*
2110	 * There is no free space in the found leaf.
2111	 * We're gonna add a new leaf in the tree.
2112	 */
2113	if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2114		mb_flags |= EXT4_MB_USE_RESERVED;
2115	path = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2116					path, newext);
2117	if (IS_ERR(path))
2118		return path;
2119	depth = ext_depth(inode);
2120	eh = path[depth].p_hdr;
2121
2122has_space:
2123	nearex = path[depth].p_ext;
2124
2125	err = ext4_ext_get_access(handle, inode, path + depth);
2126	if (err)
2127		goto errout;
2128
2129	if (!nearex) {
2130		/* there is no extent in this leaf, create first one */
2131		ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",
2132				le32_to_cpu(newext->ee_block),
2133				ext4_ext_pblock(newext),
2134				ext4_ext_is_unwritten(newext),
2135				ext4_ext_get_actual_len(newext));
2136		nearex = EXT_FIRST_EXTENT(eh);
2137	} else {
2138		if (le32_to_cpu(newext->ee_block)
2139			   > le32_to_cpu(nearex->ee_block)) {
2140			/* Insert after */
2141			ext_debug(inode, "insert %u:%llu:[%d]%d before: "
2142					"nearest %p\n",
2143					le32_to_cpu(newext->ee_block),
2144					ext4_ext_pblock(newext),
2145					ext4_ext_is_unwritten(newext),
2146					ext4_ext_get_actual_len(newext),
2147					nearex);
2148			nearex++;
2149		} else {
2150			/* Insert before */
2151			BUG_ON(newext->ee_block == nearex->ee_block);
2152			ext_debug(inode, "insert %u:%llu:[%d]%d after: "
2153					"nearest %p\n",
2154					le32_to_cpu(newext->ee_block),
2155					ext4_ext_pblock(newext),
2156					ext4_ext_is_unwritten(newext),
2157					ext4_ext_get_actual_len(newext),
2158					nearex);
2159		}
2160		len = EXT_LAST_EXTENT(eh) - nearex + 1;
2161		if (len > 0) {
2162			ext_debug(inode, "insert %u:%llu:[%d]%d: "
2163					"move %d extents from 0x%p to 0x%p\n",
2164					le32_to_cpu(newext->ee_block),
2165					ext4_ext_pblock(newext),
2166					ext4_ext_is_unwritten(newext),
2167					ext4_ext_get_actual_len(newext),
2168					len, nearex, nearex + 1);
2169			memmove(nearex + 1, nearex,
2170				len * sizeof(struct ext4_extent));
2171		}
2172	}
2173
2174	le16_add_cpu(&eh->eh_entries, 1);
2175	path[depth].p_ext = nearex;
2176	nearex->ee_block = newext->ee_block;
2177	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2178	nearex->ee_len = newext->ee_len;
2179
2180merge:
2181	/* try to merge extents */
2182	if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2183		ext4_ext_try_to_merge(handle, inode, path, nearex);
2184
 
2185	/* time to correct all indexes above */
2186	err = ext4_ext_correct_indexes(handle, inode, path);
2187	if (err)
2188		goto errout;
2189
2190	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2191	if (err)
2192		goto errout;
2193
2194	return path;
2195
2196errout:
2197	ext4_free_ext_path(path);
2198	return ERR_PTR(err);
 
2199}
2200
2201static int ext4_fill_es_cache_info(struct inode *inode,
2202				   ext4_lblk_t block, ext4_lblk_t num,
2203				   struct fiemap_extent_info *fieinfo)
2204{
2205	ext4_lblk_t next, end = block + num - 1;
2206	struct extent_status es;
2207	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2208	unsigned int flags;
2209	int err;
2210
2211	while (block <= end) {
2212		next = 0;
2213		flags = 0;
2214		if (!ext4_es_lookup_extent(inode, block, &next, &es))
2215			break;
2216		if (ext4_es_is_unwritten(&es))
2217			flags |= FIEMAP_EXTENT_UNWRITTEN;
2218		if (ext4_es_is_delayed(&es))
2219			flags |= (FIEMAP_EXTENT_DELALLOC |
2220				  FIEMAP_EXTENT_UNKNOWN);
2221		if (ext4_es_is_hole(&es))
2222			flags |= EXT4_FIEMAP_EXTENT_HOLE;
2223		if (next == 0)
2224			flags |= FIEMAP_EXTENT_LAST;
2225		if (flags & (FIEMAP_EXTENT_DELALLOC|
2226			     EXT4_FIEMAP_EXTENT_HOLE))
2227			es.es_pblk = 0;
2228		else
2229			es.es_pblk = ext4_es_pblock(&es);
2230		err = fiemap_fill_next_extent(fieinfo,
2231				(__u64)es.es_lblk << blksize_bits,
2232				(__u64)es.es_pblk << blksize_bits,
2233				(__u64)es.es_len << blksize_bits,
2234				flags);
2235		if (next == 0)
2236			break;
2237		block = next;
2238		if (err < 0)
2239			return err;
2240		if (err == 1)
2241			return 0;
2242	}
2243	return 0;
2244}
2245
2246
2247/*
2248 * ext4_ext_find_hole - find hole around given block according to the given path
2249 * @inode:	inode we lookup in
2250 * @path:	path in extent tree to @lblk
2251 * @lblk:	pointer to logical block around which we want to determine hole
2252 *
2253 * Determine hole length (and start if easily possible) around given logical
2254 * block. We don't try too hard to find the beginning of the hole but @path
2255 * actually points to extent before @lblk, we provide it.
2256 *
2257 * The function returns the length of a hole starting at @lblk. We update @lblk
2258 * to the beginning of the hole if we managed to find it.
2259 */
2260static ext4_lblk_t ext4_ext_find_hole(struct inode *inode,
2261				      struct ext4_ext_path *path,
2262				      ext4_lblk_t *lblk)
2263{
2264	int depth = ext_depth(inode);
2265	struct ext4_extent *ex;
2266	ext4_lblk_t len;
2267
2268	ex = path[depth].p_ext;
2269	if (ex == NULL) {
2270		/* there is no extent yet, so gap is [0;-] */
2271		*lblk = 0;
2272		len = EXT_MAX_BLOCKS;
2273	} else if (*lblk < le32_to_cpu(ex->ee_block)) {
2274		len = le32_to_cpu(ex->ee_block) - *lblk;
2275	} else if (*lblk >= le32_to_cpu(ex->ee_block)
2276			+ ext4_ext_get_actual_len(ex)) {
2277		ext4_lblk_t next;
2278
2279		*lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2280		next = ext4_ext_next_allocated_block(path);
2281		BUG_ON(next == *lblk);
2282		len = next - *lblk;
2283	} else {
2284		BUG();
2285	}
2286	return len;
2287}
2288
2289/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2290 * ext4_ext_rm_idx:
2291 * removes index from the index block.
2292 */
2293static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2294			struct ext4_ext_path *path, int depth)
2295{
2296	int err;
2297	ext4_fsblk_t leaf;
2298	int k = depth - 1;
2299
2300	/* free index block */
2301	leaf = ext4_idx_pblock(path[k].p_idx);
2302	if (unlikely(path[k].p_hdr->eh_entries == 0)) {
2303		EXT4_ERROR_INODE(inode, "path[%d].p_hdr->eh_entries == 0", k);
 
 
2304		return -EFSCORRUPTED;
2305	}
2306	err = ext4_ext_get_access(handle, inode, path + k);
2307	if (err)
2308		return err;
2309
2310	if (path[k].p_idx != EXT_LAST_INDEX(path[k].p_hdr)) {
2311		int len = EXT_LAST_INDEX(path[k].p_hdr) - path[k].p_idx;
2312		len *= sizeof(struct ext4_extent_idx);
2313		memmove(path[k].p_idx, path[k].p_idx + 1, len);
2314	}
2315
2316	le16_add_cpu(&path[k].p_hdr->eh_entries, -1);
2317	err = ext4_ext_dirty(handle, inode, path + k);
2318	if (err)
2319		return err;
2320	ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);
2321	trace_ext4_ext_rm_idx(inode, leaf);
2322
2323	ext4_free_blocks(handle, inode, NULL, leaf, 1,
2324			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2325
2326	while (--k >= 0) {
2327		if (path[k + 1].p_idx != EXT_FIRST_INDEX(path[k + 1].p_hdr))
2328			break;
2329		err = ext4_ext_get_access(handle, inode, path + k);
 
2330		if (err)
2331			goto clean;
2332		path[k].p_idx->ei_block = path[k + 1].p_idx->ei_block;
2333		err = ext4_ext_dirty(handle, inode, path + k);
2334		if (err)
2335			goto clean;
2336	}
2337	return 0;
2338
2339clean:
2340	/*
2341	 * The path[k].p_bh is either unmodified or with no verified bit
2342	 * set (see ext4_ext_get_access()). So just clear the verified bit
2343	 * of the successfully modified extents buffers, which will force
2344	 * these extents to be checked to avoid using inconsistent data.
2345	 */
2346	while (++k < depth)
2347		clear_buffer_verified(path[k].p_bh);
2348
2349	return err;
2350}
2351
2352/*
2353 * ext4_ext_calc_credits_for_single_extent:
2354 * This routine returns max. credits that needed to insert an extent
2355 * to the extent tree.
2356 * When pass the actual path, the caller should calculate credits
2357 * under i_data_sem.
2358 */
2359int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2360						struct ext4_ext_path *path)
2361{
2362	if (path) {
2363		int depth = ext_depth(inode);
2364		int ret = 0;
2365
2366		/* probably there is space in leaf? */
2367		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2368				< le16_to_cpu(path[depth].p_hdr->eh_max)) {
2369
2370			/*
2371			 *  There are some space in the leaf tree, no
2372			 *  need to account for leaf block credit
2373			 *
2374			 *  bitmaps and block group descriptor blocks
2375			 *  and other metadata blocks still need to be
2376			 *  accounted.
2377			 */
2378			/* 1 bitmap, 1 block group descriptor */
2379			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2380			return ret;
2381		}
2382	}
2383
2384	return ext4_chunk_trans_blocks(inode, nrblocks);
2385}
2386
2387/*
2388 * How many index/leaf blocks need to change/allocate to add @extents extents?
2389 *
2390 * If we add a single extent, then in the worse case, each tree level
2391 * index/leaf need to be changed in case of the tree split.
2392 *
2393 * If more extents are inserted, they could cause the whole tree split more
2394 * than once, but this is really rare.
2395 */
2396int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2397{
2398	int index;
2399	int depth;
2400
2401	/* If we are converting the inline data, only one is needed here. */
2402	if (ext4_has_inline_data(inode))
2403		return 1;
2404
2405	depth = ext_depth(inode);
2406
2407	if (extents <= 1)
2408		index = depth * 2;
2409	else
2410		index = depth * 3;
2411
2412	return index;
2413}
2414
2415static inline int get_default_free_blocks_flags(struct inode *inode)
2416{
2417	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2418	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2419		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2420	else if (ext4_should_journal_data(inode))
2421		return EXT4_FREE_BLOCKS_FORGET;
2422	return 0;
2423}
2424
2425/*
2426 * ext4_rereserve_cluster - increment the reserved cluster count when
2427 *                          freeing a cluster with a pending reservation
2428 *
2429 * @inode - file containing the cluster
2430 * @lblk - logical block in cluster to be reserved
2431 *
2432 * Increments the reserved cluster count and adjusts quota in a bigalloc
2433 * file system when freeing a partial cluster containing at least one
2434 * delayed and unwritten block.  A partial cluster meeting that
2435 * requirement will have a pending reservation.  If so, the
2436 * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2437 * defer reserved and allocated space accounting to a subsequent call
2438 * to this function.
2439 */
2440static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2441{
2442	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2443	struct ext4_inode_info *ei = EXT4_I(inode);
2444
2445	dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2446
2447	spin_lock(&ei->i_block_reservation_lock);
2448	ei->i_reserved_data_blocks++;
2449	percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2450	spin_unlock(&ei->i_block_reservation_lock);
2451
2452	percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2453	ext4_remove_pending(inode, lblk);
2454}
2455
2456static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2457			      struct ext4_extent *ex,
2458			      struct partial_cluster *partial,
2459			      ext4_lblk_t from, ext4_lblk_t to)
2460{
2461	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2462	unsigned short ee_len = ext4_ext_get_actual_len(ex);
2463	ext4_fsblk_t last_pblk, pblk;
2464	ext4_lblk_t num;
2465	int flags;
2466
2467	/* only extent tail removal is allowed */
2468	if (from < le32_to_cpu(ex->ee_block) ||
2469	    to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2470		ext4_error(sbi->s_sb,
2471			   "strange request: removal(2) %u-%u from %u:%u",
2472			   from, to, le32_to_cpu(ex->ee_block), ee_len);
2473		return 0;
2474	}
2475
2476#ifdef EXTENTS_STATS
2477	spin_lock(&sbi->s_ext_stats_lock);
2478	sbi->s_ext_blocks += ee_len;
2479	sbi->s_ext_extents++;
2480	if (ee_len < sbi->s_ext_min)
2481		sbi->s_ext_min = ee_len;
2482	if (ee_len > sbi->s_ext_max)
2483		sbi->s_ext_max = ee_len;
2484	if (ext_depth(inode) > sbi->s_depth_max)
2485		sbi->s_depth_max = ext_depth(inode);
2486	spin_unlock(&sbi->s_ext_stats_lock);
2487#endif
2488
2489	trace_ext4_remove_blocks(inode, ex, from, to, partial);
2490
2491	/*
2492	 * if we have a partial cluster, and it's different from the
2493	 * cluster of the last block in the extent, we free it
2494	 */
2495	last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2496
2497	if (partial->state != initial &&
2498	    partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2499		if (partial->state == tofree) {
2500			flags = get_default_free_blocks_flags(inode);
2501			if (ext4_is_pending(inode, partial->lblk))
2502				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2503			ext4_free_blocks(handle, inode, NULL,
2504					 EXT4_C2B(sbi, partial->pclu),
2505					 sbi->s_cluster_ratio, flags);
2506			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2507				ext4_rereserve_cluster(inode, partial->lblk);
2508		}
2509		partial->state = initial;
2510	}
2511
2512	num = le32_to_cpu(ex->ee_block) + ee_len - from;
2513	pblk = ext4_ext_pblock(ex) + ee_len - num;
2514
2515	/*
2516	 * We free the partial cluster at the end of the extent (if any),
2517	 * unless the cluster is used by another extent (partial_cluster
2518	 * state is nofree).  If a partial cluster exists here, it must be
2519	 * shared with the last block in the extent.
2520	 */
2521	flags = get_default_free_blocks_flags(inode);
2522
2523	/* partial, left end cluster aligned, right end unaligned */
2524	if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2525	    (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2526	    (partial->state != nofree)) {
2527		if (ext4_is_pending(inode, to))
2528			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2529		ext4_free_blocks(handle, inode, NULL,
2530				 EXT4_PBLK_CMASK(sbi, last_pblk),
2531				 sbi->s_cluster_ratio, flags);
2532		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2533			ext4_rereserve_cluster(inode, to);
2534		partial->state = initial;
2535		flags = get_default_free_blocks_flags(inode);
2536	}
2537
2538	flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2539
2540	/*
2541	 * For bigalloc file systems, we never free a partial cluster
2542	 * at the beginning of the extent.  Instead, we check to see if we
2543	 * need to free it on a subsequent call to ext4_remove_blocks,
2544	 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2545	 */
2546	flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2547	ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2548
2549	/* reset the partial cluster if we've freed past it */
2550	if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2551		partial->state = initial;
2552
2553	/*
2554	 * If we've freed the entire extent but the beginning is not left
2555	 * cluster aligned and is not marked as ineligible for freeing we
2556	 * record the partial cluster at the beginning of the extent.  It
2557	 * wasn't freed by the preceding ext4_free_blocks() call, and we
2558	 * need to look farther to the left to determine if it's to be freed
2559	 * (not shared with another extent). Else, reset the partial
2560	 * cluster - we're either  done freeing or the beginning of the
2561	 * extent is left cluster aligned.
2562	 */
2563	if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2564		if (partial->state == initial) {
2565			partial->pclu = EXT4_B2C(sbi, pblk);
2566			partial->lblk = from;
2567			partial->state = tofree;
2568		}
2569	} else {
2570		partial->state = initial;
2571	}
2572
2573	return 0;
2574}
2575
2576/*
2577 * ext4_ext_rm_leaf() Removes the extents associated with the
2578 * blocks appearing between "start" and "end".  Both "start"
2579 * and "end" must appear in the same extent or EIO is returned.
2580 *
2581 * @handle: The journal handle
2582 * @inode:  The files inode
2583 * @path:   The path to the leaf
2584 * @partial_cluster: The cluster which we'll have to free if all extents
2585 *                   has been released from it.  However, if this value is
2586 *                   negative, it's a cluster just to the right of the
2587 *                   punched region and it must not be freed.
2588 * @start:  The first block to remove
2589 * @end:   The last block to remove
2590 */
2591static int
2592ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2593		 struct ext4_ext_path *path,
2594		 struct partial_cluster *partial,
2595		 ext4_lblk_t start, ext4_lblk_t end)
2596{
2597	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2598	int err = 0, correct_index = 0;
2599	int depth = ext_depth(inode), credits, revoke_credits;
2600	struct ext4_extent_header *eh;
2601	ext4_lblk_t a, b;
2602	unsigned num;
2603	ext4_lblk_t ex_ee_block;
2604	unsigned short ex_ee_len;
2605	unsigned unwritten = 0;
2606	struct ext4_extent *ex;
2607	ext4_fsblk_t pblk;
2608
2609	/* the header must be checked already in ext4_ext_remove_space() */
2610	ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
2611	if (!path[depth].p_hdr)
2612		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2613	eh = path[depth].p_hdr;
2614	if (unlikely(path[depth].p_hdr == NULL)) {
2615		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2616		return -EFSCORRUPTED;
2617	}
2618	/* find where to start removing */
2619	ex = path[depth].p_ext;
2620	if (!ex)
2621		ex = EXT_LAST_EXTENT(eh);
2622
2623	ex_ee_block = le32_to_cpu(ex->ee_block);
2624	ex_ee_len = ext4_ext_get_actual_len(ex);
2625
2626	trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2627
2628	while (ex >= EXT_FIRST_EXTENT(eh) &&
2629			ex_ee_block + ex_ee_len > start) {
2630
2631		if (ext4_ext_is_unwritten(ex))
2632			unwritten = 1;
2633		else
2634			unwritten = 0;
2635
2636		ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
2637			  unwritten, ex_ee_len);
2638		path[depth].p_ext = ex;
2639
2640		a = max(ex_ee_block, start);
2641		b = min(ex_ee_block + ex_ee_len - 1, end);
 
2642
2643		ext_debug(inode, "  border %u:%u\n", a, b);
2644
2645		/* If this extent is beyond the end of the hole, skip it */
2646		if (end < ex_ee_block) {
2647			/*
2648			 * We're going to skip this extent and move to another,
2649			 * so note that its first cluster is in use to avoid
2650			 * freeing it when removing blocks.  Eventually, the
2651			 * right edge of the truncated/punched region will
2652			 * be just to the left.
2653			 */
2654			if (sbi->s_cluster_ratio > 1) {
2655				pblk = ext4_ext_pblock(ex);
2656				partial->pclu = EXT4_B2C(sbi, pblk);
2657				partial->state = nofree;
2658			}
2659			ex--;
2660			ex_ee_block = le32_to_cpu(ex->ee_block);
2661			ex_ee_len = ext4_ext_get_actual_len(ex);
2662			continue;
2663		} else if (b != ex_ee_block + ex_ee_len - 1) {
2664			EXT4_ERROR_INODE(inode,
2665					 "can not handle truncate %u:%u "
2666					 "on extent %u:%u",
2667					 start, end, ex_ee_block,
2668					 ex_ee_block + ex_ee_len - 1);
2669			err = -EFSCORRUPTED;
2670			goto out;
2671		} else if (a != ex_ee_block) {
2672			/* remove tail of the extent */
2673			num = a - ex_ee_block;
2674		} else {
2675			/* remove whole extent: excellent! */
2676			num = 0;
2677		}
2678		/*
2679		 * 3 for leaf, sb, and inode plus 2 (bmap and group
2680		 * descriptor) for each block group; assume two block
2681		 * groups plus ex_ee_len/blocks_per_block_group for
2682		 * the worst case
2683		 */
2684		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2685		if (ex == EXT_FIRST_EXTENT(eh)) {
2686			correct_index = 1;
2687			credits += (ext_depth(inode)) + 1;
2688		}
2689		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2690		/*
2691		 * We may end up freeing some index blocks and data from the
2692		 * punched range. Note that partial clusters are accounted for
2693		 * by ext4_free_data_revoke_credits().
2694		 */
2695		revoke_credits =
2696			ext4_free_metadata_revoke_credits(inode->i_sb,
2697							  ext_depth(inode)) +
2698			ext4_free_data_revoke_credits(inode, b - a + 1);
2699
2700		err = ext4_datasem_ensure_credits(handle, inode, credits,
2701						  credits, revoke_credits);
2702		if (err) {
2703			if (err > 0)
2704				err = -EAGAIN;
2705			goto out;
2706		}
2707
2708		err = ext4_ext_get_access(handle, inode, path + depth);
2709		if (err)
2710			goto out;
2711
2712		err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2713		if (err)
2714			goto out;
2715
2716		if (num == 0)
2717			/* this extent is removed; mark slot entirely unused */
2718			ext4_ext_store_pblock(ex, 0);
2719
2720		ex->ee_len = cpu_to_le16(num);
2721		/*
2722		 * Do not mark unwritten if all the blocks in the
2723		 * extent have been removed.
2724		 */
2725		if (unwritten && num)
2726			ext4_ext_mark_unwritten(ex);
2727		/*
2728		 * If the extent was completely released,
2729		 * we need to remove it from the leaf
2730		 */
2731		if (num == 0) {
2732			if (end != EXT_MAX_BLOCKS - 1) {
2733				/*
2734				 * For hole punching, we need to scoot all the
2735				 * extents up when an extent is removed so that
2736				 * we dont have blank extents in the middle
2737				 */
2738				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2739					sizeof(struct ext4_extent));
2740
2741				/* Now get rid of the one at the end */
2742				memset(EXT_LAST_EXTENT(eh), 0,
2743					sizeof(struct ext4_extent));
2744			}
2745			le16_add_cpu(&eh->eh_entries, -1);
2746		}
2747
2748		err = ext4_ext_dirty(handle, inode, path + depth);
2749		if (err)
2750			goto out;
2751
2752		ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
2753				ext4_ext_pblock(ex));
2754		ex--;
2755		ex_ee_block = le32_to_cpu(ex->ee_block);
2756		ex_ee_len = ext4_ext_get_actual_len(ex);
2757	}
2758
2759	if (correct_index && eh->eh_entries)
2760		err = ext4_ext_correct_indexes(handle, inode, path);
2761
2762	/*
2763	 * If there's a partial cluster and at least one extent remains in
2764	 * the leaf, free the partial cluster if it isn't shared with the
2765	 * current extent.  If it is shared with the current extent
2766	 * we reset the partial cluster because we've reached the start of the
2767	 * truncated/punched region and we're done removing blocks.
2768	 */
2769	if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2770		pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2771		if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2772			int flags = get_default_free_blocks_flags(inode);
2773
2774			if (ext4_is_pending(inode, partial->lblk))
2775				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2776			ext4_free_blocks(handle, inode, NULL,
2777					 EXT4_C2B(sbi, partial->pclu),
2778					 sbi->s_cluster_ratio, flags);
2779			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2780				ext4_rereserve_cluster(inode, partial->lblk);
2781		}
2782		partial->state = initial;
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	struct partial_cluster partial;
2822	handle_t *handle;
2823	int i = 0, err = 0;
2824
2825	partial.pclu = 0;
2826	partial.lblk = 0;
2827	partial.state = initial;
2828
2829	ext_debug(inode, "truncate since %u to %u\n", start, end);
2830
2831	/* probably first extent we're gonna free will be last in block */
2832	handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2833			depth + 1,
2834			ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2835	if (IS_ERR(handle))
2836		return PTR_ERR(handle);
2837
2838again:
2839	trace_ext4_ext_remove_space(inode, start, end, depth);
2840
2841	/*
2842	 * Check if we are removing extents inside the extent tree. If that
2843	 * is the case, we are going to punch a hole inside the extent tree
2844	 * so we have to check whether we need to split the extent covering
2845	 * the last block to remove so we can easily remove the part of it
2846	 * in ext4_ext_rm_leaf().
2847	 */
2848	if (end < EXT_MAX_BLOCKS - 1) {
2849		struct ext4_extent *ex;
2850		ext4_lblk_t ee_block, ex_end, lblk;
2851		ext4_fsblk_t pblk;
2852
2853		/* find extent for or closest extent to this block */
2854		path = ext4_find_extent(inode, end, NULL,
2855					EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);
2856		if (IS_ERR(path)) {
2857			ext4_journal_stop(handle);
2858			return PTR_ERR(path);
2859		}
2860		depth = ext_depth(inode);
2861		/* Leaf not may not exist only if inode has no blocks at all */
2862		ex = path[depth].p_ext;
2863		if (!ex) {
2864			if (depth) {
2865				EXT4_ERROR_INODE(inode,
2866						 "path[%d].p_hdr == NULL",
2867						 depth);
2868				err = -EFSCORRUPTED;
2869			}
2870			goto out;
2871		}
2872
2873		ee_block = le32_to_cpu(ex->ee_block);
2874		ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2875
2876		/*
2877		 * See if the last block is inside the extent, if so split
2878		 * the extent at 'end' block so we can easily remove the
2879		 * tail of the first part of the split extent in
2880		 * ext4_ext_rm_leaf().
2881		 */
2882		if (end >= ee_block && end < ex_end) {
2883
2884			/*
2885			 * If we're going to split the extent, note that
2886			 * the cluster containing the block after 'end' is
2887			 * in use to avoid freeing it when removing blocks.
2888			 */
2889			if (sbi->s_cluster_ratio > 1) {
2890				pblk = ext4_ext_pblock(ex) + end - ee_block + 1;
2891				partial.pclu = EXT4_B2C(sbi, pblk);
2892				partial.state = nofree;
2893			}
2894
2895			/*
2896			 * Split the extent in two so that 'end' is the last
2897			 * block in the first new extent. Also we should not
2898			 * fail removing space due to ENOSPC so try to use
2899			 * reserved block if that happens.
2900			 */
2901			path = ext4_force_split_extent_at(handle, inode, path,
2902							  end + 1, 1);
2903			if (IS_ERR(path)) {
2904				err = PTR_ERR(path);
2905				goto out;
2906			}
2907		} else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
2908			   partial.state == initial) {
2909			/*
2910			 * If we're punching, there's an extent to the right.
2911			 * If the partial cluster hasn't been set, set it to
2912			 * that extent's first cluster and its state to nofree
2913			 * so it won't be freed should it contain blocks to be
2914			 * removed. If it's already set (tofree/nofree), we're
2915			 * retrying and keep the original partial cluster info
2916			 * so a cluster marked tofree as a result of earlier
2917			 * extent removal is not lost.
2918			 */
2919			lblk = ex_end + 1;
2920			err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2921						    NULL);
2922			if (err < 0)
2923				goto out;
2924			if (pblk) {
2925				partial.pclu = EXT4_B2C(sbi, pblk);
2926				partial.state = nofree;
2927			}
2928		}
2929	}
2930	/*
2931	 * We start scanning from right side, freeing all the blocks
2932	 * after i_size and walking into the tree depth-wise.
2933	 */
2934	depth = ext_depth(inode);
2935	if (path) {
2936		int k = i = depth;
2937		while (--k > 0)
2938			path[k].p_block =
2939				le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2940	} else {
2941		path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
2942			       GFP_NOFS | __GFP_NOFAIL);
2943		if (path == NULL) {
2944			ext4_journal_stop(handle);
2945			return -ENOMEM;
2946		}
2947		path[0].p_maxdepth = path[0].p_depth = depth;
2948		path[0].p_hdr = ext_inode_hdr(inode);
2949		i = 0;
2950
2951		if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2952			err = -EFSCORRUPTED;
2953			goto out;
2954		}
2955	}
2956	err = 0;
2957
2958	while (i >= 0 && err == 0) {
2959		if (i == depth) {
2960			/* this is leaf block */
2961			err = ext4_ext_rm_leaf(handle, inode, path,
2962					       &partial, start, end);
2963			/* root level has p_bh == NULL, brelse() eats this */
2964			ext4_ext_path_brelse(path + i);
 
2965			i--;
2966			continue;
2967		}
2968
2969		/* this is index block */
2970		if (!path[i].p_hdr) {
2971			ext_debug(inode, "initialize header\n");
2972			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2973		}
2974
2975		if (!path[i].p_idx) {
2976			/* this level hasn't been touched yet */
2977			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2978			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2979			ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
2980				  path[i].p_hdr,
2981				  le16_to_cpu(path[i].p_hdr->eh_entries));
2982		} else {
2983			/* we were already here, see at next index */
2984			path[i].p_idx--;
2985		}
2986
2987		ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
2988				i, EXT_FIRST_INDEX(path[i].p_hdr),
2989				path[i].p_idx);
2990		if (ext4_ext_more_to_rm(path + i)) {
2991			struct buffer_head *bh;
2992			/* go to the next level */
2993			ext_debug(inode, "move to level %d (block %llu)\n",
2994				  i + 1, ext4_idx_pblock(path[i].p_idx));
2995			memset(path + i + 1, 0, sizeof(*path));
2996			bh = read_extent_tree_block(inode, path[i].p_idx,
2997						    depth - i - 1,
2998						    EXT4_EX_NOCACHE);
2999			if (IS_ERR(bh)) {
3000				/* should we reset i_size? */
3001				err = PTR_ERR(bh);
3002				break;
3003			}
3004			/* Yield here to deal with large extent trees.
3005			 * Should be a no-op if we did IO above. */
3006			cond_resched();
3007			if (WARN_ON(i + 1 > depth)) {
3008				err = -EFSCORRUPTED;
3009				break;
3010			}
3011			path[i + 1].p_bh = bh;
3012
3013			/* save actual number of indexes since this
3014			 * number is changed at the next iteration */
3015			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3016			i++;
3017		} else {
3018			/* we finished processing this index, go up */
3019			if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3020				/* index is empty, remove it;
3021				 * handle must be already prepared by the
3022				 * truncatei_leaf() */
3023				err = ext4_ext_rm_idx(handle, inode, path, i);
3024			}
3025			/* root level has p_bh == NULL, brelse() eats this */
3026			ext4_ext_path_brelse(path + i);
 
3027			i--;
3028			ext_debug(inode, "return to level %d\n", i);
3029		}
3030	}
3031
3032	trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3033					 path->p_hdr->eh_entries);
3034
3035	/*
3036	 * if there's a partial cluster and we have removed the first extent
3037	 * in the file, then we also free the partial cluster, if any
3038	 */
3039	if (partial.state == tofree && err == 0) {
3040		int flags = get_default_free_blocks_flags(inode);
3041
3042		if (ext4_is_pending(inode, partial.lblk))
3043			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3044		ext4_free_blocks(handle, inode, NULL,
3045				 EXT4_C2B(sbi, partial.pclu),
3046				 sbi->s_cluster_ratio, flags);
3047		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3048			ext4_rereserve_cluster(inode, partial.lblk);
3049		partial.state = initial;
3050	}
3051
3052	/* TODO: flexible tree reduction should be here */
3053	if (path->p_hdr->eh_entries == 0) {
3054		/*
3055		 * truncate to zero freed all the tree,
3056		 * so we need to correct eh_depth
3057		 */
3058		err = ext4_ext_get_access(handle, inode, path);
3059		if (err == 0) {
3060			ext_inode_hdr(inode)->eh_depth = 0;
3061			ext_inode_hdr(inode)->eh_max =
3062				cpu_to_le16(ext4_ext_space_root(inode, 0));
3063			err = ext4_ext_dirty(handle, inode, path);
3064		}
3065	}
3066out:
3067	ext4_free_ext_path(path);
 
3068	path = NULL;
3069	if (err == -EAGAIN)
3070		goto again;
3071	ext4_journal_stop(handle);
3072
3073	return err;
3074}
3075
3076/*
3077 * called at mount time
3078 */
3079void ext4_ext_init(struct super_block *sb)
3080{
3081	/*
3082	 * possible initialization would be here
3083	 */
3084
3085	if (ext4_has_feature_extents(sb)) {
3086#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3087		printk(KERN_INFO "EXT4-fs: file extents enabled"
3088#ifdef AGGRESSIVE_TEST
3089		       ", aggressive tests"
3090#endif
3091#ifdef CHECK_BINSEARCH
3092		       ", check binsearch"
3093#endif
3094#ifdef EXTENTS_STATS
3095		       ", stats"
3096#endif
3097		       "\n");
3098#endif
3099#ifdef EXTENTS_STATS
3100		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3101		EXT4_SB(sb)->s_ext_min = 1 << 30;
3102		EXT4_SB(sb)->s_ext_max = 0;
3103#endif
3104	}
3105}
3106
3107/*
3108 * called at umount time
3109 */
3110void ext4_ext_release(struct super_block *sb)
3111{
3112	if (!ext4_has_feature_extents(sb))
3113		return;
3114
3115#ifdef EXTENTS_STATS
3116	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3117		struct ext4_sb_info *sbi = EXT4_SB(sb);
3118		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3119			sbi->s_ext_blocks, sbi->s_ext_extents,
3120			sbi->s_ext_blocks / sbi->s_ext_extents);
3121		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3122			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3123	}
3124#endif
3125}
3126
3127static void ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3128{
3129	ext4_lblk_t  ee_block;
3130	ext4_fsblk_t ee_pblock;
3131	unsigned int ee_len;
3132
3133	ee_block  = le32_to_cpu(ex->ee_block);
3134	ee_len    = ext4_ext_get_actual_len(ex);
3135	ee_pblock = ext4_ext_pblock(ex);
3136
3137	if (ee_len == 0)
3138		return;
3139
3140	ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3141			      EXTENT_STATUS_WRITTEN, false);
3142}
3143
3144/* FIXME!! we need to try to merge to left or right after zero-out  */
3145static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3146{
3147	ext4_fsblk_t ee_pblock;
3148	unsigned int ee_len;
3149
3150	ee_len    = ext4_ext_get_actual_len(ex);
3151	ee_pblock = ext4_ext_pblock(ex);
3152	return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3153				  ee_len);
3154}
3155
3156/*
3157 * ext4_split_extent_at() splits an extent at given block.
3158 *
3159 * @handle: the journal handle
3160 * @inode: the file inode
3161 * @path: the path to the extent
3162 * @split: the logical block where the extent is splitted.
3163 * @split_flags: indicates if the extent could be zeroout if split fails, and
3164 *		 the states(init or unwritten) of new extents.
3165 * @flags: flags used to insert new extent to extent tree.
3166 *
3167 *
3168 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3169 * of which are determined by split_flag.
3170 *
3171 * There are two cases:
3172 *  a> the extent are splitted into two extent.
3173 *  b> split is not needed, and just mark the extent.
3174 *
3175 * Return an extent path pointer on success, or an error pointer on failure.
3176 */
3177static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
3178						  struct inode *inode,
3179						  struct ext4_ext_path *path,
3180						  ext4_lblk_t split,
3181						  int split_flag, int flags)
 
3182{
 
3183	ext4_fsblk_t newblock;
3184	ext4_lblk_t ee_block;
3185	struct ext4_extent *ex, newex, orig_ex, zero_ex;
3186	struct ext4_extent *ex2 = NULL;
3187	unsigned int ee_len, depth;
3188	int err = 0;
3189
3190	BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3191	       (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3192
3193	ext_debug(inode, "logical block %llu\n", (unsigned long long)split);
3194
3195	ext4_ext_show_leaf(inode, path);
3196
3197	depth = ext_depth(inode);
3198	ex = path[depth].p_ext;
3199	ee_block = le32_to_cpu(ex->ee_block);
3200	ee_len = ext4_ext_get_actual_len(ex);
3201	newblock = split - ee_block + ext4_ext_pblock(ex);
3202
3203	BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3204	BUG_ON(!ext4_ext_is_unwritten(ex) &&
3205	       split_flag & (EXT4_EXT_MAY_ZEROOUT |
3206			     EXT4_EXT_MARK_UNWRIT1 |
3207			     EXT4_EXT_MARK_UNWRIT2));
3208
3209	err = ext4_ext_get_access(handle, inode, path + depth);
3210	if (err)
3211		goto out;
3212
3213	if (split == ee_block) {
3214		/*
3215		 * case b: block @split is the block that the extent begins with
3216		 * then we just change the state of the extent, and splitting
3217		 * is not needed.
3218		 */
3219		if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3220			ext4_ext_mark_unwritten(ex);
3221		else
3222			ext4_ext_mark_initialized(ex);
3223
3224		if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3225			ext4_ext_try_to_merge(handle, inode, path, ex);
3226
3227		err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3228		goto out;
3229	}
3230
3231	/* case a */
3232	memcpy(&orig_ex, ex, sizeof(orig_ex));
3233	ex->ee_len = cpu_to_le16(split - ee_block);
3234	if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3235		ext4_ext_mark_unwritten(ex);
3236
3237	/*
3238	 * path may lead to new leaf, not to original leaf any more
3239	 * after ext4_ext_insert_extent() returns,
3240	 */
3241	err = ext4_ext_dirty(handle, inode, path + depth);
3242	if (err)
3243		goto fix_extent_len;
3244
3245	ex2 = &newex;
3246	ex2->ee_block = cpu_to_le32(split);
3247	ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3248	ext4_ext_store_pblock(ex2, newblock);
3249	if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3250		ext4_ext_mark_unwritten(ex2);
3251
3252	path = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
3253	if (!IS_ERR(path))
3254		goto out;
3255
3256	err = PTR_ERR(path);
3257	if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
3258		return path;
3259
3260	/*
3261	 * Get a new path to try to zeroout or fix the extent length.
3262	 * Using EXT4_EX_NOFAIL guarantees that ext4_find_extent()
3263	 * will not return -ENOMEM, otherwise -ENOMEM will cause a
3264	 * retry in do_writepages(), and a WARN_ON may be triggered
3265	 * in ext4_da_update_reserve_space() due to an incorrect
3266	 * ee_len causing the i_reserved_data_blocks exception.
3267	 */
3268	path = ext4_find_extent(inode, ee_block, NULL, flags | EXT4_EX_NOFAIL);
3269	if (IS_ERR(path)) {
3270		EXT4_ERROR_INODE(inode, "Failed split extent on %u, err %ld",
3271				 split, PTR_ERR(path));
3272		return path;
3273	}
3274	depth = ext_depth(inode);
3275	ex = path[depth].p_ext;
3276
3277	if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
3278		if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3279			if (split_flag & EXT4_EXT_DATA_VALID1) {
3280				err = ext4_ext_zeroout(inode, ex2);
3281				zero_ex.ee_block = ex2->ee_block;
3282				zero_ex.ee_len = cpu_to_le16(
3283						ext4_ext_get_actual_len(ex2));
3284				ext4_ext_store_pblock(&zero_ex,
3285						      ext4_ext_pblock(ex2));
3286			} else {
3287				err = ext4_ext_zeroout(inode, ex);
3288				zero_ex.ee_block = ex->ee_block;
3289				zero_ex.ee_len = cpu_to_le16(
3290						ext4_ext_get_actual_len(ex));
3291				ext4_ext_store_pblock(&zero_ex,
3292						      ext4_ext_pblock(ex));
3293			}
3294		} else {
3295			err = ext4_ext_zeroout(inode, &orig_ex);
3296			zero_ex.ee_block = orig_ex.ee_block;
3297			zero_ex.ee_len = cpu_to_le16(
3298						ext4_ext_get_actual_len(&orig_ex));
3299			ext4_ext_store_pblock(&zero_ex,
3300					      ext4_ext_pblock(&orig_ex));
3301		}
3302
3303		if (!err) {
3304			/* update the extent length and mark as initialized */
3305			ex->ee_len = cpu_to_le16(ee_len);
3306			ext4_ext_try_to_merge(handle, inode, path, ex);
3307			err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3308			if (!err)
3309				/* update extent status tree */
3310				ext4_zeroout_es(inode, &zero_ex);
3311			/* If we failed at this point, we don't know in which
3312			 * state the extent tree exactly is so don't try to fix
3313			 * length of the original extent as it may do even more
3314			 * damage.
3315			 */
3316			goto out;
3317		}
3318	}
 
 
 
3319
3320fix_extent_len:
3321	ex->ee_len = orig_ex.ee_len;
3322	/*
3323	 * Ignore ext4_ext_dirty return value since we are already in error path
3324	 * and err is a non-zero error code.
3325	 */
3326	ext4_ext_dirty(handle, inode, path + path->p_depth);
3327out:
3328	if (err) {
3329		ext4_free_ext_path(path);
3330		path = ERR_PTR(err);
3331	}
3332	ext4_ext_show_leaf(inode, path);
3333	return path;
3334}
3335
3336/*
3337 * ext4_split_extent() splits an extent and mark extent which is covered
3338 * by @map as split_flags indicates
3339 *
3340 * It may result in splitting the extent into multiple extents (up to three)
3341 * There are three possibilities:
3342 *   a> There is no split required
3343 *   b> Splits in two extents: Split is happening at either end of the extent
3344 *   c> Splits in three extents: Somone is splitting in middle of the extent
3345 *
3346 */
3347static struct ext4_ext_path *ext4_split_extent(handle_t *handle,
3348					       struct inode *inode,
3349					       struct ext4_ext_path *path,
3350					       struct ext4_map_blocks *map,
3351					       int split_flag, int flags,
3352					       unsigned int *allocated)
3353{
 
3354	ext4_lblk_t ee_block;
3355	struct ext4_extent *ex;
3356	unsigned int ee_len, depth;
 
3357	int unwritten;
3358	int split_flag1, flags1;
 
3359
3360	depth = ext_depth(inode);
3361	ex = path[depth].p_ext;
3362	ee_block = le32_to_cpu(ex->ee_block);
3363	ee_len = ext4_ext_get_actual_len(ex);
3364	unwritten = ext4_ext_is_unwritten(ex);
3365
3366	if (map->m_lblk + map->m_len < ee_block + ee_len) {
3367		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3368		flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3369		if (unwritten)
3370			split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3371				       EXT4_EXT_MARK_UNWRIT2;
3372		if (split_flag & EXT4_EXT_DATA_VALID2)
3373			split_flag1 |= EXT4_EXT_DATA_VALID1;
3374		path = ext4_split_extent_at(handle, inode, path,
3375				map->m_lblk + map->m_len, split_flag1, flags1);
3376		if (IS_ERR(path))
3377			return path;
3378		/*
3379		 * Update path is required because previous ext4_split_extent_at
3380		 * may result in split of original leaf or extent zeroout.
3381		 */
3382		path = ext4_find_extent(inode, map->m_lblk, path, flags);
3383		if (IS_ERR(path))
3384			return path;
3385		depth = ext_depth(inode);
3386		ex = path[depth].p_ext;
3387		if (!ex) {
3388			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3389					(unsigned long) map->m_lblk);
3390			ext4_free_ext_path(path);
3391			return ERR_PTR(-EFSCORRUPTED);
3392		}
3393		unwritten = ext4_ext_is_unwritten(ex);
3394	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3395
3396	if (map->m_lblk >= ee_block) {
3397		split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3398		if (unwritten) {
3399			split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3400			split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3401						     EXT4_EXT_MARK_UNWRIT2);
3402		}
3403		path = ext4_split_extent_at(handle, inode, path,
3404				map->m_lblk, split_flag1, flags);
3405		if (IS_ERR(path))
3406			return path;
3407	}
3408
3409	if (allocated) {
3410		if (map->m_lblk + map->m_len > ee_block + ee_len)
3411			*allocated = ee_len - (map->m_lblk - ee_block);
3412		else
3413			*allocated = map->m_len;
3414	}
3415	ext4_ext_show_leaf(inode, path);
3416	return path;
 
3417}
3418
3419/*
3420 * This function is called by ext4_ext_map_blocks() if someone tries to write
3421 * to an unwritten extent. It may result in splitting the unwritten
3422 * extent into multiple extents (up to three - one initialized and two
3423 * unwritten).
3424 * There are three possibilities:
3425 *   a> There is no split required: Entire extent should be initialized
3426 *   b> Splits in two extents: Write is happening at either end of the extent
3427 *   c> Splits in three extents: Somone is writing in middle of the extent
3428 *
3429 * Pre-conditions:
3430 *  - The extent pointed to by 'path' is unwritten.
3431 *  - The extent pointed to by 'path' contains a superset
3432 *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3433 *
3434 * Post-conditions on success:
3435 *  - the returned value is the number of blocks beyond map->l_lblk
3436 *    that are allocated and initialized.
3437 *    It is guaranteed to be >= map->m_len.
3438 */
3439static struct ext4_ext_path *
3440ext4_ext_convert_to_initialized(handle_t *handle, struct inode *inode,
3441			struct ext4_map_blocks *map, struct ext4_ext_path *path,
3442			int flags, unsigned int *allocated)
 
3443{
 
3444	struct ext4_sb_info *sbi;
3445	struct ext4_extent_header *eh;
3446	struct ext4_map_blocks split_map;
3447	struct ext4_extent zero_ex1, zero_ex2;
3448	struct ext4_extent *ex, *abut_ex;
3449	ext4_lblk_t ee_block, eof_block;
3450	unsigned int ee_len, depth, map_len = map->m_len;
 
3451	int err = 0;
3452	int split_flag = EXT4_EXT_DATA_VALID2;
3453	unsigned int max_zeroout = 0;
3454
3455	ext_debug(inode, "logical block %llu, max_blocks %u\n",
3456		  (unsigned long long)map->m_lblk, map_len);
3457
3458	sbi = EXT4_SB(inode->i_sb);
3459	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3460			>> inode->i_sb->s_blocksize_bits;
3461	if (eof_block < map->m_lblk + map_len)
3462		eof_block = map->m_lblk + map_len;
3463
3464	depth = ext_depth(inode);
3465	eh = path[depth].p_hdr;
3466	ex = path[depth].p_ext;
3467	ee_block = le32_to_cpu(ex->ee_block);
3468	ee_len = ext4_ext_get_actual_len(ex);
3469	zero_ex1.ee_len = 0;
3470	zero_ex2.ee_len = 0;
3471
3472	trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3473
3474	/* Pre-conditions */
3475	BUG_ON(!ext4_ext_is_unwritten(ex));
3476	BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3477
3478	/*
3479	 * Attempt to transfer newly initialized blocks from the currently
3480	 * unwritten extent to its neighbor. This is much cheaper
3481	 * than an insertion followed by a merge as those involve costly
3482	 * memmove() calls. Transferring to the left is the common case in
3483	 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3484	 * followed by append writes.
3485	 *
3486	 * Limitations of the current logic:
3487	 *  - L1: we do not deal with writes covering the whole extent.
3488	 *    This would require removing the extent if the transfer
3489	 *    is possible.
3490	 *  - L2: we only attempt to merge with an extent stored in the
3491	 *    same extent tree node.
3492	 */
3493	*allocated = 0;
3494	if ((map->m_lblk == ee_block) &&
3495		/* See if we can merge left */
3496		(map_len < ee_len) &&		/*L1*/
3497		(ex > EXT_FIRST_EXTENT(eh))) {	/*L2*/
3498		ext4_lblk_t prev_lblk;
3499		ext4_fsblk_t prev_pblk, ee_pblk;
3500		unsigned int prev_len;
3501
3502		abut_ex = ex - 1;
3503		prev_lblk = le32_to_cpu(abut_ex->ee_block);
3504		prev_len = ext4_ext_get_actual_len(abut_ex);
3505		prev_pblk = ext4_ext_pblock(abut_ex);
3506		ee_pblk = ext4_ext_pblock(ex);
3507
3508		/*
3509		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3510		 * upon those conditions:
3511		 * - C1: abut_ex is initialized,
3512		 * - C2: abut_ex is logically abutting ex,
3513		 * - C3: abut_ex is physically abutting ex,
3514		 * - C4: abut_ex can receive the additional blocks without
3515		 *   overflowing the (initialized) length limit.
3516		 */
3517		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
3518			((prev_lblk + prev_len) == ee_block) &&		/*C2*/
3519			((prev_pblk + prev_len) == ee_pblk) &&		/*C3*/
3520			(prev_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
3521			err = ext4_ext_get_access(handle, inode, path + depth);
3522			if (err)
3523				goto errout;
3524
3525			trace_ext4_ext_convert_to_initialized_fastpath(inode,
3526				map, ex, abut_ex);
3527
3528			/* Shift the start of ex by 'map_len' blocks */
3529			ex->ee_block = cpu_to_le32(ee_block + map_len);
3530			ext4_ext_store_pblock(ex, ee_pblk + map_len);
3531			ex->ee_len = cpu_to_le16(ee_len - map_len);
3532			ext4_ext_mark_unwritten(ex); /* Restore the flag */
3533
3534			/* Extend abut_ex by 'map_len' blocks */
3535			abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3536
3537			/* Result: number of initialized blocks past m_lblk */
3538			*allocated = map_len;
3539		}
3540	} else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3541		   (map_len < ee_len) &&	/*L1*/
3542		   ex < EXT_LAST_EXTENT(eh)) {	/*L2*/
3543		/* See if we can merge right */
3544		ext4_lblk_t next_lblk;
3545		ext4_fsblk_t next_pblk, ee_pblk;
3546		unsigned int next_len;
3547
3548		abut_ex = ex + 1;
3549		next_lblk = le32_to_cpu(abut_ex->ee_block);
3550		next_len = ext4_ext_get_actual_len(abut_ex);
3551		next_pblk = ext4_ext_pblock(abut_ex);
3552		ee_pblk = ext4_ext_pblock(ex);
3553
3554		/*
3555		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3556		 * upon those conditions:
3557		 * - C1: abut_ex is initialized,
3558		 * - C2: abut_ex is logically abutting ex,
3559		 * - C3: abut_ex is physically abutting ex,
3560		 * - C4: abut_ex can receive the additional blocks without
3561		 *   overflowing the (initialized) length limit.
3562		 */
3563		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/
3564		    ((map->m_lblk + map_len) == next_lblk) &&		/*C2*/
3565		    ((ee_pblk + ee_len) == next_pblk) &&		/*C3*/
3566		    (next_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/
3567			err = ext4_ext_get_access(handle, inode, path + depth);
3568			if (err)
3569				goto errout;
3570
3571			trace_ext4_ext_convert_to_initialized_fastpath(inode,
3572				map, ex, abut_ex);
3573
3574			/* Shift the start of abut_ex by 'map_len' blocks */
3575			abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3576			ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3577			ex->ee_len = cpu_to_le16(ee_len - map_len);
3578			ext4_ext_mark_unwritten(ex); /* Restore the flag */
3579
3580			/* Extend abut_ex by 'map_len' blocks */
3581			abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3582
3583			/* Result: number of initialized blocks past m_lblk */
3584			*allocated = map_len;
3585		}
3586	}
3587	if (*allocated) {
3588		/* Mark the block containing both extents as dirty */
3589		err = ext4_ext_dirty(handle, inode, path + depth);
3590
3591		/* Update path to point to the right extent */
3592		path[depth].p_ext = abut_ex;
3593		if (err)
3594			goto errout;
3595		goto out;
3596	} else
3597		*allocated = ee_len - (map->m_lblk - ee_block);
3598
3599	WARN_ON(map->m_lblk < ee_block);
3600	/*
3601	 * It is safe to convert extent to initialized via explicit
3602	 * zeroout only if extent is fully inside i_size or new_size.
3603	 */
3604	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3605
3606	if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3607		max_zeroout = sbi->s_extent_max_zeroout_kb >>
3608			(inode->i_sb->s_blocksize_bits - 10);
3609
3610	/*
3611	 * five cases:
3612	 * 1. split the extent into three extents.
3613	 * 2. split the extent into two extents, zeroout the head of the first
3614	 *    extent.
3615	 * 3. split the extent into two extents, zeroout the tail of the second
3616	 *    extent.
3617	 * 4. split the extent into two extents with out zeroout.
3618	 * 5. no splitting needed, just possibly zeroout the head and / or the
3619	 *    tail of the extent.
3620	 */
3621	split_map.m_lblk = map->m_lblk;
3622	split_map.m_len = map->m_len;
3623
3624	if (max_zeroout && (*allocated > split_map.m_len)) {
3625		if (*allocated <= max_zeroout) {
3626			/* case 3 or 5 */
3627			zero_ex1.ee_block =
3628				 cpu_to_le32(split_map.m_lblk +
3629					     split_map.m_len);
3630			zero_ex1.ee_len =
3631				cpu_to_le16(*allocated - split_map.m_len);
3632			ext4_ext_store_pblock(&zero_ex1,
3633				ext4_ext_pblock(ex) + split_map.m_lblk +
3634				split_map.m_len - ee_block);
3635			err = ext4_ext_zeroout(inode, &zero_ex1);
3636			if (err)
3637				goto fallback;
3638			split_map.m_len = *allocated;
3639		}
3640		if (split_map.m_lblk - ee_block + split_map.m_len <
3641								max_zeroout) {
3642			/* case 2 or 5 */
3643			if (split_map.m_lblk != ee_block) {
3644				zero_ex2.ee_block = ex->ee_block;
3645				zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3646							ee_block);
3647				ext4_ext_store_pblock(&zero_ex2,
3648						      ext4_ext_pblock(ex));
3649				err = ext4_ext_zeroout(inode, &zero_ex2);
3650				if (err)
3651					goto fallback;
3652			}
3653
3654			split_map.m_len += split_map.m_lblk - ee_block;
3655			split_map.m_lblk = ee_block;
3656			*allocated = map->m_len;
3657		}
3658	}
3659
3660fallback:
3661	path = ext4_split_extent(handle, inode, path, &split_map, split_flag,
3662				 flags, NULL);
3663	if (IS_ERR(path))
3664		return path;
3665out:
3666	/* If we have gotten a failure, don't zero out status tree */
3667	ext4_zeroout_es(inode, &zero_ex1);
3668	ext4_zeroout_es(inode, &zero_ex2);
3669	return path;
3670
3671errout:
3672	ext4_free_ext_path(path);
3673	return ERR_PTR(err);
3674}
3675
3676/*
3677 * This function is called by ext4_ext_map_blocks() from
3678 * ext4_get_blocks_dio_write() when DIO to write
3679 * to an unwritten extent.
3680 *
3681 * Writing to an unwritten extent may result in splitting the unwritten
3682 * extent into multiple initialized/unwritten extents (up to three)
3683 * There are three possibilities:
3684 *   a> There is no split required: Entire extent should be unwritten
3685 *   b> Splits in two extents: Write is happening at either end of the extent
3686 *   c> Splits in three extents: Somone is writing in middle of the extent
3687 *
3688 * This works the same way in the case of initialized -> unwritten conversion.
3689 *
3690 * One of more index blocks maybe needed if the extent tree grow after
3691 * the unwritten extent split. To prevent ENOSPC occur at the IO
3692 * complete, we need to split the unwritten extent before DIO submit
3693 * the IO. The unwritten extent called at this time will be split
3694 * into three unwritten extent(at most). After IO complete, the part
3695 * being filled will be convert to initialized by the end_io callback function
3696 * via ext4_convert_unwritten_extents().
3697 *
3698 * The size of unwritten extent to be written is passed to the caller via the
3699 * allocated pointer. Return an extent path pointer on success, or an error
3700 * pointer on failure.
3701 */
3702static struct ext4_ext_path *ext4_split_convert_extents(handle_t *handle,
3703					struct inode *inode,
3704					struct ext4_map_blocks *map,
3705					struct ext4_ext_path *path,
3706					int flags, unsigned int *allocated)
3707{
 
3708	ext4_lblk_t eof_block;
3709	ext4_lblk_t ee_block;
3710	struct ext4_extent *ex;
3711	unsigned int ee_len;
3712	int split_flag = 0, depth;
3713
3714	ext_debug(inode, "logical block %llu, max_blocks %u\n",
3715		  (unsigned long long)map->m_lblk, map->m_len);
3716
3717	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
3718			>> inode->i_sb->s_blocksize_bits;
3719	if (eof_block < map->m_lblk + map->m_len)
3720		eof_block = map->m_lblk + map->m_len;
3721	/*
3722	 * It is safe to convert extent to initialized via explicit
3723	 * zeroout only if extent is fully inside i_size or new_size.
3724	 */
3725	depth = ext_depth(inode);
3726	ex = path[depth].p_ext;
3727	ee_block = le32_to_cpu(ex->ee_block);
3728	ee_len = ext4_ext_get_actual_len(ex);
3729
3730	/* Convert to unwritten */
3731	if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3732		split_flag |= EXT4_EXT_DATA_VALID1;
3733	/* Convert to initialized */
3734	} else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3735		split_flag |= ee_block + ee_len <= eof_block ?
3736			      EXT4_EXT_MAY_ZEROOUT : 0;
3737		split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3738	}
3739	flags |= EXT4_GET_BLOCKS_PRE_IO;
3740	return ext4_split_extent(handle, inode, path, map, split_flag, flags,
3741				 allocated);
3742}
3743
3744static struct ext4_ext_path *
3745ext4_convert_unwritten_extents_endio(handle_t *handle, struct inode *inode,
3746				     struct ext4_map_blocks *map,
3747				     struct ext4_ext_path *path)
3748{
 
3749	struct ext4_extent *ex;
3750	ext4_lblk_t ee_block;
3751	unsigned int ee_len;
3752	int depth;
3753	int err = 0;
3754
3755	depth = ext_depth(inode);
3756	ex = path[depth].p_ext;
3757	ee_block = le32_to_cpu(ex->ee_block);
3758	ee_len = ext4_ext_get_actual_len(ex);
3759
3760	ext_debug(inode, "logical block %llu, max_blocks %u\n",
3761		  (unsigned long long)ee_block, ee_len);
3762
3763	/* If extent is larger than requested it is a clear sign that we still
3764	 * have some extent state machine issues left. So extent_split is still
3765	 * required.
3766	 * TODO: Once all related issues will be fixed this situation should be
3767	 * illegal.
3768	 */
3769	if (ee_block != map->m_lblk || ee_len > map->m_len) {
3770#ifdef CONFIG_EXT4_DEBUG
3771		ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3772			     " len %u; IO logical block %llu, len %u",
3773			     inode->i_ino, (unsigned long long)ee_block, ee_len,
3774			     (unsigned long long)map->m_lblk, map->m_len);
3775#endif
3776		path = ext4_split_convert_extents(handle, inode, map, path,
3777						EXT4_GET_BLOCKS_CONVERT, NULL);
3778		if (IS_ERR(path))
3779			return path;
3780
3781		path = ext4_find_extent(inode, map->m_lblk, path, 0);
3782		if (IS_ERR(path))
3783			return path;
3784		depth = ext_depth(inode);
3785		ex = path[depth].p_ext;
3786	}
3787
3788	err = ext4_ext_get_access(handle, inode, path + depth);
3789	if (err)
3790		goto errout;
3791	/* first mark the extent as initialized */
3792	ext4_ext_mark_initialized(ex);
3793
3794	/* note: ext4_ext_correct_indexes() isn't needed here because
3795	 * borders are not changed
3796	 */
3797	ext4_ext_try_to_merge(handle, inode, path, ex);
3798
3799	/* Mark modified extent as dirty */
3800	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3801	if (err)
3802		goto errout;
3803
3804	ext4_ext_show_leaf(inode, path);
3805	return path;
3806
3807errout:
3808	ext4_free_ext_path(path);
3809	return ERR_PTR(err);
3810}
3811
3812static struct ext4_ext_path *
3813convert_initialized_extent(handle_t *handle, struct inode *inode,
3814			   struct ext4_map_blocks *map,
3815			   struct ext4_ext_path *path,
3816			   unsigned int *allocated)
3817{
 
3818	struct ext4_extent *ex;
3819	ext4_lblk_t ee_block;
3820	unsigned int ee_len;
3821	int depth;
3822	int err = 0;
3823
3824	/*
3825	 * Make sure that the extent is no bigger than we support with
3826	 * unwritten extent
3827	 */
3828	if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3829		map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3830
3831	depth = ext_depth(inode);
3832	ex = path[depth].p_ext;
3833	ee_block = le32_to_cpu(ex->ee_block);
3834	ee_len = ext4_ext_get_actual_len(ex);
3835
3836	ext_debug(inode, "logical block %llu, max_blocks %u\n",
3837		  (unsigned long long)ee_block, ee_len);
3838
3839	if (ee_block != map->m_lblk || ee_len > map->m_len) {
3840		path = ext4_split_convert_extents(handle, inode, map, path,
3841				EXT4_GET_BLOCKS_CONVERT_UNWRITTEN, NULL);
3842		if (IS_ERR(path))
3843			return path;
3844
3845		path = ext4_find_extent(inode, map->m_lblk, path, 0);
3846		if (IS_ERR(path))
3847			return path;
3848		depth = ext_depth(inode);
3849		ex = path[depth].p_ext;
3850		if (!ex) {
3851			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3852					 (unsigned long) map->m_lblk);
3853			err = -EFSCORRUPTED;
3854			goto errout;
3855		}
3856	}
3857
3858	err = ext4_ext_get_access(handle, inode, path + depth);
3859	if (err)
3860		goto errout;
3861	/* first mark the extent as unwritten */
3862	ext4_ext_mark_unwritten(ex);
3863
3864	/* note: ext4_ext_correct_indexes() isn't needed here because
3865	 * borders are not changed
3866	 */
3867	ext4_ext_try_to_merge(handle, inode, path, ex);
3868
3869	/* Mark modified extent as dirty */
3870	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3871	if (err)
3872		goto errout;
3873	ext4_ext_show_leaf(inode, path);
3874
3875	ext4_update_inode_fsync_trans(handle, inode, 1);
3876
3877	map->m_flags |= EXT4_MAP_UNWRITTEN;
3878	if (*allocated > map->m_len)
3879		*allocated = map->m_len;
3880	map->m_len = *allocated;
3881	return path;
3882
3883errout:
3884	ext4_free_ext_path(path);
3885	return ERR_PTR(err);
3886}
3887
3888static struct ext4_ext_path *
3889ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
3890			struct ext4_map_blocks *map,
3891			struct ext4_ext_path *path, int flags,
3892			unsigned int *allocated, ext4_fsblk_t newblock)
3893{
 
 
3894	int err = 0;
3895
3896	ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",
3897		  (unsigned long long)map->m_lblk, map->m_len, flags,
3898		  *allocated);
3899	ext4_ext_show_leaf(inode, path);
3900
3901	/*
3902	 * When writing into unwritten space, we should not fail to
3903	 * allocate metadata blocks for the new extent block if needed.
3904	 */
3905	flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3906
3907	trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
3908						*allocated, newblock);
3909
3910	/* get_block() before submitting IO, split the extent */
3911	if (flags & EXT4_GET_BLOCKS_PRE_IO) {
3912		path = ext4_split_convert_extents(handle, inode, map, path,
3913				flags | EXT4_GET_BLOCKS_CONVERT, allocated);
3914		if (IS_ERR(path))
3915			return path;
 
 
3916		/*
3917		 * shouldn't get a 0 allocated when splitting an extent unless
3918		 * m_len is 0 (bug) or extent has been corrupted
3919		 */
3920		if (unlikely(*allocated == 0)) {
3921			EXT4_ERROR_INODE(inode,
3922					 "unexpected allocated == 0, m_len = %u",
3923					 map->m_len);
3924			err = -EFSCORRUPTED;
3925			goto errout;
3926		}
3927		map->m_flags |= EXT4_MAP_UNWRITTEN;
3928		goto out;
3929	}
3930	/* IO end_io complete, convert the filled extent to written */
3931	if (flags & EXT4_GET_BLOCKS_CONVERT) {
3932		path = ext4_convert_unwritten_extents_endio(handle, inode,
3933							    map, path);
3934		if (IS_ERR(path))
3935			return path;
3936		ext4_update_inode_fsync_trans(handle, inode, 1);
3937		goto map_out;
3938	}
3939	/* buffered IO cases */
3940	/*
3941	 * repeat fallocate creation request
3942	 * we already have an unwritten extent
3943	 */
3944	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
3945		map->m_flags |= EXT4_MAP_UNWRITTEN;
3946		goto map_out;
3947	}
3948
3949	/* buffered READ or buffered write_begin() lookup */
3950	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3951		/*
3952		 * We have blocks reserved already.  We
3953		 * return allocated blocks so that delalloc
3954		 * won't do block reservation for us.  But
3955		 * the buffer head will be unmapped so that
3956		 * a read from the block returns 0s.
3957		 */
3958		map->m_flags |= EXT4_MAP_UNWRITTEN;
3959		goto out1;
3960	}
3961
3962	/*
3963	 * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.
3964	 * For buffered writes, at writepage time, etc.  Convert a
3965	 * discovered unwritten extent to written.
3966	 */
3967	path = ext4_ext_convert_to_initialized(handle, inode, map, path,
3968					       flags, allocated);
3969	if (IS_ERR(path))
3970		return path;
 
3971	ext4_update_inode_fsync_trans(handle, inode, 1);
3972	/*
3973	 * shouldn't get a 0 allocated when converting an unwritten extent
3974	 * unless m_len is 0 (bug) or extent has been corrupted
3975	 */
3976	if (unlikely(*allocated == 0)) {
3977		EXT4_ERROR_INODE(inode, "unexpected allocated == 0, m_len = %u",
3978				 map->m_len);
3979		err = -EFSCORRUPTED;
3980		goto errout;
3981	}
3982
3983out:
 
3984	map->m_flags |= EXT4_MAP_NEW;
3985map_out:
3986	map->m_flags |= EXT4_MAP_MAPPED;
3987out1:
3988	map->m_pblk = newblock;
3989	if (*allocated > map->m_len)
3990		*allocated = map->m_len;
3991	map->m_len = *allocated;
3992	ext4_ext_show_leaf(inode, path);
3993	return path;
3994
3995errout:
3996	ext4_free_ext_path(path);
3997	return ERR_PTR(err);
3998}
3999
4000/*
4001 * get_implied_cluster_alloc - check to see if the requested
4002 * allocation (in the map structure) overlaps with a cluster already
4003 * allocated in an extent.
4004 *	@sb	The filesystem superblock structure
4005 *	@map	The requested lblk->pblk mapping
4006 *	@ex	The extent structure which might contain an implied
4007 *			cluster allocation
4008 *
4009 * This function is called by ext4_ext_map_blocks() after we failed to
4010 * find blocks that were already in the inode's extent tree.  Hence,
4011 * we know that the beginning of the requested region cannot overlap
4012 * the extent from the inode's extent tree.  There are three cases we
4013 * want to catch.  The first is this case:
4014 *
4015 *		 |--- cluster # N--|
4016 *    |--- extent ---|	|---- requested region ---|
4017 *			|==========|
4018 *
4019 * The second case that we need to test for is this one:
4020 *
4021 *   |--------- cluster # N ----------------|
4022 *	   |--- requested region --|   |------- extent ----|
4023 *	   |=======================|
4024 *
4025 * The third case is when the requested region lies between two extents
4026 * within the same cluster:
4027 *          |------------- cluster # N-------------|
4028 * |----- ex -----|                  |---- ex_right ----|
4029 *                  |------ requested region ------|
4030 *                  |================|
4031 *
4032 * In each of the above cases, we need to set the map->m_pblk and
4033 * map->m_len so it corresponds to the return the extent labelled as
4034 * "|====|" from cluster #N, since it is already in use for data in
4035 * cluster EXT4_B2C(sbi, map->m_lblk).	We will then return 1 to
4036 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4037 * as a new "allocated" block region.  Otherwise, we will return 0 and
4038 * ext4_ext_map_blocks() will then allocate one or more new clusters
4039 * by calling ext4_mb_new_blocks().
4040 */
4041static int get_implied_cluster_alloc(struct super_block *sb,
4042				     struct ext4_map_blocks *map,
4043				     struct ext4_extent *ex,
4044				     struct ext4_ext_path *path)
4045{
4046	struct ext4_sb_info *sbi = EXT4_SB(sb);
4047	ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4048	ext4_lblk_t ex_cluster_start, ex_cluster_end;
4049	ext4_lblk_t rr_cluster_start;
4050	ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4051	ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4052	unsigned short ee_len = ext4_ext_get_actual_len(ex);
4053
4054	/* The extent passed in that we are trying to match */
4055	ex_cluster_start = EXT4_B2C(sbi, ee_block);
4056	ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4057
4058	/* The requested region passed into ext4_map_blocks() */
4059	rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4060
4061	if ((rr_cluster_start == ex_cluster_end) ||
4062	    (rr_cluster_start == ex_cluster_start)) {
4063		if (rr_cluster_start == ex_cluster_end)
4064			ee_start += ee_len - 1;
4065		map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4066		map->m_len = min(map->m_len,
4067				 (unsigned) sbi->s_cluster_ratio - c_offset);
4068		/*
4069		 * Check for and handle this case:
4070		 *
4071		 *   |--------- cluster # N-------------|
4072		 *		       |------- extent ----|
4073		 *	   |--- requested region ---|
4074		 *	   |===========|
4075		 */
4076
4077		if (map->m_lblk < ee_block)
4078			map->m_len = min(map->m_len, ee_block - map->m_lblk);
4079
4080		/*
4081		 * Check for the case where there is already another allocated
4082		 * block to the right of 'ex' but before the end of the cluster.
4083		 *
4084		 *          |------------- cluster # N-------------|
4085		 * |----- ex -----|                  |---- ex_right ----|
4086		 *                  |------ requested region ------|
4087		 *                  |================|
4088		 */
4089		if (map->m_lblk > ee_block) {
4090			ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4091			map->m_len = min(map->m_len, next - map->m_lblk);
4092		}
4093
4094		trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4095		return 1;
4096	}
4097
4098	trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4099	return 0;
4100}
4101
4102/*
4103 * Determine hole length around the given logical block, first try to
4104 * locate and expand the hole from the given @path, and then adjust it
4105 * if it's partially or completely converted to delayed extents, insert
4106 * it into the extent cache tree if it's indeed a hole, finally return
4107 * the length of the determined extent.
4108 */
4109static ext4_lblk_t ext4_ext_determine_insert_hole(struct inode *inode,
4110						  struct ext4_ext_path *path,
4111						  ext4_lblk_t lblk)
4112{
4113	ext4_lblk_t hole_start, len;
4114	struct extent_status es;
4115
4116	hole_start = lblk;
4117	len = ext4_ext_find_hole(inode, path, &hole_start);
4118again:
4119	ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
4120				  hole_start + len - 1, &es);
4121	if (!es.es_len)
4122		goto insert_hole;
4123
4124	/*
4125	 * There's a delalloc extent in the hole, handle it if the delalloc
4126	 * extent is in front of, behind and straddle the queried range.
4127	 */
4128	if (lblk >= es.es_lblk + es.es_len) {
4129		/*
4130		 * The delalloc extent is in front of the queried range,
4131		 * find again from the queried start block.
4132		 */
4133		len -= lblk - hole_start;
4134		hole_start = lblk;
4135		goto again;
4136	} else if (in_range(lblk, es.es_lblk, es.es_len)) {
4137		/*
4138		 * The delalloc extent containing lblk, it must have been
4139		 * added after ext4_map_blocks() checked the extent status
4140		 * tree so we are not holding i_rwsem and delalloc info is
4141		 * only stabilized by i_data_sem we are going to release
4142		 * soon. Don't modify the extent status tree and report
4143		 * extent as a hole, just adjust the length to the delalloc
4144		 * extent's after lblk.
4145		 */
4146		len = es.es_lblk + es.es_len - lblk;
4147		return len;
4148	} else {
4149		/*
4150		 * The delalloc extent is partially or completely behind
4151		 * the queried range, update hole length until the
4152		 * beginning of the delalloc extent.
4153		 */
4154		len = min(es.es_lblk - hole_start, len);
4155	}
4156
4157insert_hole:
4158	/* Put just found gap into cache to speed up subsequent requests */
4159	ext_debug(inode, " -> %u:%u\n", hole_start, len);
4160	ext4_es_insert_extent(inode, hole_start, len, ~0,
4161			      EXTENT_STATUS_HOLE, false);
4162
4163	/* Update hole_len to reflect hole size after lblk */
4164	if (hole_start != lblk)
4165		len -= lblk - hole_start;
4166
4167	return len;
4168}
4169
4170/*
4171 * Block allocation/map/preallocation routine for extents based files
4172 *
4173 *
4174 * Need to be called with
4175 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4176 * (ie, flags is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4177 *
4178 * return > 0, number of blocks already mapped/allocated
4179 *          if flags doesn't contain EXT4_GET_BLOCKS_CREATE and these are pre-allocated blocks
4180 *          	buffer head is unmapped
4181 *          otherwise blocks are mapped
4182 *
4183 * return = 0, if plain look up failed (blocks have not been allocated)
4184 *          buffer head is unmapped
4185 *
4186 * return < 0, error case.
4187 */
4188int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4189			struct ext4_map_blocks *map, int flags)
4190{
4191	struct ext4_ext_path *path = NULL;
4192	struct ext4_extent newex, *ex, ex2;
4193	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4194	ext4_fsblk_t newblock = 0, pblk;
4195	int err = 0, depth;
4196	unsigned int allocated = 0, offset = 0;
4197	unsigned int allocated_clusters = 0;
4198	struct ext4_allocation_request ar;
4199	ext4_lblk_t cluster_offset;
4200
4201	ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);
4202	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4203
4204	/* find extent for this block */
4205	path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4206	if (IS_ERR(path)) {
4207		err = PTR_ERR(path);
 
4208		goto out;
4209	}
4210
4211	depth = ext_depth(inode);
4212
4213	/*
4214	 * consistent leaf must not be empty;
4215	 * this situation is possible, though, _during_ tree modification;
4216	 * this is why assert can't be put in ext4_find_extent()
4217	 */
4218	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4219		EXT4_ERROR_INODE(inode, "bad extent address "
4220				 "lblock: %lu, depth: %d pblock %lld",
4221				 (unsigned long) map->m_lblk, depth,
4222				 path[depth].p_block);
4223		err = -EFSCORRUPTED;
4224		goto out;
4225	}
4226
4227	ex = path[depth].p_ext;
4228	if (ex) {
4229		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4230		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4231		unsigned short ee_len;
4232
4233
4234		/*
4235		 * unwritten extents are treated as holes, except that
4236		 * we split out initialized portions during a write.
4237		 */
4238		ee_len = ext4_ext_get_actual_len(ex);
4239
4240		trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4241
4242		/* if found extent covers block, simply return it */
4243		if (in_range(map->m_lblk, ee_block, ee_len)) {
4244			newblock = map->m_lblk - ee_block + ee_start;
4245			/* number of remaining blocks in the extent */
4246			allocated = ee_len - (map->m_lblk - ee_block);
4247			ext_debug(inode, "%u fit into %u:%d -> %llu\n",
4248				  map->m_lblk, ee_block, ee_len, newblock);
4249
4250			/*
4251			 * If the extent is initialized check whether the
4252			 * caller wants to convert it to unwritten.
4253			 */
4254			if ((!ext4_ext_is_unwritten(ex)) &&
4255			    (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4256				path = convert_initialized_extent(handle,
4257					inode, map, path, &allocated);
4258				if (IS_ERR(path))
4259					err = PTR_ERR(path);
4260				goto out;
4261			} else if (!ext4_ext_is_unwritten(ex)) {
4262				map->m_flags |= EXT4_MAP_MAPPED;
4263				map->m_pblk = newblock;
4264				if (allocated > map->m_len)
4265					allocated = map->m_len;
4266				map->m_len = allocated;
4267				ext4_ext_show_leaf(inode, path);
4268				goto out;
4269			}
4270
4271			path = ext4_ext_handle_unwritten_extents(
4272				handle, inode, map, path, flags,
4273				&allocated, newblock);
4274			if (IS_ERR(path))
4275				err = PTR_ERR(path);
 
 
4276			goto out;
4277		}
4278	}
4279
4280	/*
4281	 * requested block isn't allocated yet;
4282	 * we couldn't try to create block if flags doesn't contain EXT4_GET_BLOCKS_CREATE
4283	 */
4284	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4285		ext4_lblk_t len;
4286
4287		len = ext4_ext_determine_insert_hole(inode, path, map->m_lblk);
 
 
 
 
 
 
4288
 
 
 
4289		map->m_pblk = 0;
4290		map->m_len = min_t(unsigned int, map->m_len, len);
 
4291		goto out;
4292	}
4293
4294	/*
4295	 * Okay, we need to do block allocation.
4296	 */
4297	newex.ee_block = cpu_to_le32(map->m_lblk);
4298	cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4299
4300	/*
4301	 * If we are doing bigalloc, check to see if the extent returned
4302	 * by ext4_find_extent() implies a cluster we can use.
4303	 */
4304	if (cluster_offset && ex &&
4305	    get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4306		ar.len = allocated = map->m_len;
4307		newblock = map->m_pblk;
4308		goto got_allocated_blocks;
4309	}
4310
4311	/* find neighbour allocated blocks */
4312	ar.lleft = map->m_lblk;
4313	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4314	if (err)
4315		goto out;
4316	ar.lright = map->m_lblk;
 
4317	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4318	if (err < 0)
4319		goto out;
4320
4321	/* Check if the extent after searching to the right implies a
4322	 * cluster we can use. */
4323	if ((sbi->s_cluster_ratio > 1) && err &&
4324	    get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {
4325		ar.len = allocated = map->m_len;
4326		newblock = map->m_pblk;
4327		err = 0;
4328		goto got_allocated_blocks;
4329	}
4330
4331	/*
4332	 * See if request is beyond maximum number of blocks we can have in
4333	 * a single extent. For an initialized extent this limit is
4334	 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4335	 * EXT_UNWRITTEN_MAX_LEN.
4336	 */
4337	if (map->m_len > EXT_INIT_MAX_LEN &&
4338	    !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4339		map->m_len = EXT_INIT_MAX_LEN;
4340	else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4341		 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4342		map->m_len = EXT_UNWRITTEN_MAX_LEN;
4343
4344	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4345	newex.ee_len = cpu_to_le16(map->m_len);
4346	err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4347	if (err)
4348		allocated = ext4_ext_get_actual_len(&newex);
4349	else
4350		allocated = map->m_len;
4351
4352	/* allocate new block */
4353	ar.inode = inode;
4354	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4355	ar.logical = map->m_lblk;
4356	/*
4357	 * We calculate the offset from the beginning of the cluster
4358	 * for the logical block number, since when we allocate a
4359	 * physical cluster, the physical block should start at the
4360	 * same offset from the beginning of the cluster.  This is
4361	 * needed so that future calls to get_implied_cluster_alloc()
4362	 * work correctly.
4363	 */
4364	offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4365	ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4366	ar.goal -= offset;
4367	ar.logical -= offset;
4368	if (S_ISREG(inode->i_mode))
4369		ar.flags = EXT4_MB_HINT_DATA;
4370	else
4371		/* disable in-core preallocation for non-regular files */
4372		ar.flags = 0;
4373	if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4374		ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4375	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4376		ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4377	if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4378		ar.flags |= EXT4_MB_USE_RESERVED;
4379	newblock = ext4_mb_new_blocks(handle, &ar, &err);
4380	if (!newblock)
4381		goto out;
4382	allocated_clusters = ar.len;
4383	ar.len = EXT4_C2B(sbi, ar.len) - offset;
4384	ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",
4385		  ar.goal, newblock, ar.len, allocated);
4386	if (ar.len > allocated)
4387		ar.len = allocated;
4388
4389got_allocated_blocks:
4390	/* try to insert new extent into found leaf and return */
4391	pblk = newblock + offset;
4392	ext4_ext_store_pblock(&newex, pblk);
4393	newex.ee_len = cpu_to_le16(ar.len);
4394	/* Mark unwritten */
4395	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4396		ext4_ext_mark_unwritten(&newex);
4397		map->m_flags |= EXT4_MAP_UNWRITTEN;
4398	}
4399
4400	path = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
4401	if (IS_ERR(path)) {
4402		err = PTR_ERR(path);
4403		if (allocated_clusters) {
4404			int fb_flags = 0;
4405
4406			/*
4407			 * free data blocks we just allocated.
4408			 * not a good idea to call discard here directly,
4409			 * but otherwise we'd need to call it every free().
4410			 */
4411			ext4_discard_preallocations(inode);
4412			if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4413				fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;
4414			ext4_free_blocks(handle, inode, NULL, newblock,
4415					 EXT4_C2B(sbi, allocated_clusters),
4416					 fb_flags);
4417		}
4418		goto out;
4419	}
4420
4421	/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4422	 * Cache the extent and update transaction to commit on fdatasync only
4423	 * when it is _not_ an unwritten extent.
4424	 */
4425	if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4426		ext4_update_inode_fsync_trans(handle, inode, 1);
4427	else
4428		ext4_update_inode_fsync_trans(handle, inode, 0);
4429
4430	map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);
4431	map->m_pblk = pblk;
4432	map->m_len = ar.len;
4433	allocated = map->m_len;
4434	ext4_ext_show_leaf(inode, path);
 
4435out:
4436	ext4_free_ext_path(path);
 
4437
4438	trace_ext4_ext_map_blocks_exit(inode, flags, map,
4439				       err ? err : allocated);
4440	return err ? err : allocated;
4441}
4442
4443int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4444{
4445	struct super_block *sb = inode->i_sb;
4446	ext4_lblk_t last_block;
4447	int err = 0;
4448
4449	/*
4450	 * TODO: optimization is possible here.
4451	 * Probably we need not scan at all,
4452	 * because page truncation is enough.
4453	 */
4454
4455	/* we have to know where to truncate from in crash case */
4456	EXT4_I(inode)->i_disksize = inode->i_size;
4457	err = ext4_mark_inode_dirty(handle, inode);
4458	if (err)
4459		return err;
4460
4461	last_block = (inode->i_size + sb->s_blocksize - 1)
4462			>> EXT4_BLOCK_SIZE_BITS(sb);
4463	ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
4464
 
 
 
 
 
 
 
 
4465retry_remove_space:
4466	err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4467	if (err == -ENOMEM) {
4468		memalloc_retry_wait(GFP_ATOMIC);
 
4469		goto retry_remove_space;
4470	}
4471	return err;
4472}
4473
4474static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4475				  ext4_lblk_t len, loff_t new_size,
4476				  int flags)
4477{
4478	struct inode *inode = file_inode(file);
4479	handle_t *handle;
4480	int ret = 0, ret2 = 0, ret3 = 0;
 
4481	int retries = 0;
4482	int depth = 0;
4483	struct ext4_map_blocks map;
4484	unsigned int credits;
4485	loff_t epos, old_size = i_size_read(inode);
4486
4487	BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4488	map.m_lblk = offset;
4489	map.m_len = len;
4490	/*
4491	 * Don't normalize the request if it can fit in one extent so
4492	 * that it doesn't get unnecessarily split into multiple
4493	 * extents.
4494	 */
4495	if (len <= EXT_UNWRITTEN_MAX_LEN)
4496		flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4497
4498	/*
4499	 * credits to insert 1 extent into extent tree
4500	 */
4501	credits = ext4_chunk_trans_blocks(inode, len);
4502	depth = ext_depth(inode);
4503
4504retry:
4505	while (len) {
4506		/*
4507		 * Recalculate credits when extent tree depth changes.
4508		 */
4509		if (depth != ext_depth(inode)) {
4510			credits = ext4_chunk_trans_blocks(inode, len);
4511			depth = ext_depth(inode);
4512		}
4513
4514		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4515					    credits);
4516		if (IS_ERR(handle)) {
4517			ret = PTR_ERR(handle);
4518			break;
4519		}
4520		ret = ext4_map_blocks(handle, inode, &map, flags);
4521		if (ret <= 0) {
4522			ext4_debug("inode #%lu: block %u: len %u: "
4523				   "ext4_ext_map_blocks returned %d",
4524				   inode->i_ino, map.m_lblk,
4525				   map.m_len, ret);
4526			ext4_mark_inode_dirty(handle, inode);
4527			ext4_journal_stop(handle);
4528			break;
4529		}
4530		/*
4531		 * allow a full retry cycle for any remaining allocations
4532		 */
4533		retries = 0;
4534		map.m_lblk += ret;
4535		map.m_len = len = len - ret;
4536		epos = (loff_t)map.m_lblk << inode->i_blkbits;
4537		inode_set_ctime_current(inode);
4538		if (new_size) {
4539			if (epos > new_size)
4540				epos = new_size;
4541			if (ext4_update_inode_size(inode, epos) & 0x1)
4542				inode_set_mtime_to_ts(inode,
4543						      inode_get_ctime(inode));
4544			if (epos > old_size) {
4545				pagecache_isize_extended(inode, old_size, epos);
4546				ext4_zero_partial_blocks(handle, inode,
4547						     old_size, epos - old_size);
4548			}
4549		}
4550		ret2 = ext4_mark_inode_dirty(handle, inode);
4551		ext4_update_inode_fsync_trans(handle, inode, 1);
4552		ret3 = ext4_journal_stop(handle);
4553		ret2 = ret3 ? ret3 : ret2;
4554		if (unlikely(ret2))
4555			break;
4556	}
4557	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 
 
4558		goto retry;
 
4559
4560	return ret > 0 ? ret2 : ret;
4561}
4562
4563static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);
4564
4565static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
4566
4567static long ext4_zero_range(struct file *file, loff_t offset,
4568			    loff_t len, int mode)
4569{
4570	struct inode *inode = file_inode(file);
4571	struct address_space *mapping = file->f_mapping;
4572	handle_t *handle = NULL;
4573	unsigned int max_blocks;
4574	loff_t new_size = 0;
4575	int ret = 0;
4576	int flags;
4577	int credits;
4578	int partial_begin, partial_end;
4579	loff_t start, end;
4580	ext4_lblk_t lblk;
4581	unsigned int blkbits = inode->i_blkbits;
4582
4583	trace_ext4_zero_range(inode, offset, len, mode);
4584
 
 
 
 
 
 
 
4585	/*
4586	 * Round up offset. This is not fallocate, we need to zero out
4587	 * blocks, so convert interior block aligned part of the range to
4588	 * unwritten and possibly manually zero out unaligned parts of the
4589	 * range. Here, start and partial_begin are inclusive, end and
4590	 * partial_end are exclusive.
4591	 */
4592	start = round_up(offset, 1 << blkbits);
4593	end = round_down((offset + len), 1 << blkbits);
4594
4595	if (start < offset || end > offset + len)
4596		return -EINVAL;
4597	partial_begin = offset & ((1 << blkbits) - 1);
4598	partial_end = (offset + len) & ((1 << blkbits) - 1);
4599
4600	lblk = start >> blkbits;
4601	max_blocks = (end >> blkbits);
4602	if (max_blocks < lblk)
4603		max_blocks = 0;
4604	else
4605		max_blocks -= lblk;
4606
4607	inode_lock(inode);
4608
4609	/*
4610	 * Indirect files do not support unwritten extents
4611	 */
4612	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4613		ret = -EOPNOTSUPP;
4614		goto out_mutex;
4615	}
4616
4617	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4618	    (offset + len > inode->i_size ||
4619	     offset + len > EXT4_I(inode)->i_disksize)) {
4620		new_size = offset + len;
4621		ret = inode_newsize_ok(inode, new_size);
4622		if (ret)
4623			goto out_mutex;
4624	}
4625
4626	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4627
4628	/* Wait all existing dio workers, newcomers will block on i_rwsem */
4629	inode_dio_wait(inode);
4630
4631	ret = file_modified(file);
4632	if (ret)
4633		goto out_mutex;
4634
4635	/* Preallocate the range including the unaligned edges */
4636	if (partial_begin || partial_end) {
4637		ret = ext4_alloc_file_blocks(file,
4638				round_down(offset, 1 << blkbits) >> blkbits,
4639				(round_up((offset + len), 1 << blkbits) -
4640				 round_down(offset, 1 << blkbits)) >> blkbits,
4641				new_size, flags);
4642		if (ret)
4643			goto out_mutex;
4644
4645	}
4646
4647	/* Zero range excluding the unaligned edges */
4648	if (max_blocks > 0) {
4649		flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4650			  EXT4_EX_NOCACHE);
4651
4652		/*
4653		 * Prevent page faults from reinstantiating pages we have
4654		 * released from page cache.
4655		 */
4656		filemap_invalidate_lock(mapping);
4657
4658		ret = ext4_break_layouts(inode);
4659		if (ret) {
4660			filemap_invalidate_unlock(mapping);
4661			goto out_mutex;
4662		}
4663
4664		ret = ext4_update_disksize_before_punch(inode, offset, len);
4665		if (ret) {
4666			filemap_invalidate_unlock(mapping);
4667			goto out_mutex;
4668		}
4669
4670		/*
4671		 * For journalled data we need to write (and checkpoint) pages
4672		 * before discarding page cache to avoid inconsitent data on
4673		 * disk in case of crash before zeroing trans is committed.
4674		 */
4675		if (ext4_should_journal_data(inode)) {
4676			ret = filemap_write_and_wait_range(mapping, start,
4677							   end - 1);
4678			if (ret) {
4679				filemap_invalidate_unlock(mapping);
4680				goto out_mutex;
4681			}
4682		}
4683
4684		/* Now release the pages and zero block aligned part of pages */
4685		truncate_pagecache_range(inode, start, end - 1);
4686		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
4687
4688		ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4689					     flags);
4690		filemap_invalidate_unlock(mapping);
4691		if (ret)
4692			goto out_mutex;
4693	}
4694	if (!partial_begin && !partial_end)
4695		goto out_mutex;
4696
4697	/*
4698	 * In worst case we have to writeout two nonadjacent unwritten
4699	 * blocks and update the inode
4700	 */
4701	credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4702	if (ext4_should_journal_data(inode))
4703		credits += 2;
4704	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4705	if (IS_ERR(handle)) {
4706		ret = PTR_ERR(handle);
4707		ext4_std_error(inode->i_sb, ret);
4708		goto out_mutex;
4709	}
4710
4711	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
4712	if (new_size)
4713		ext4_update_inode_size(inode, new_size);
4714	ret = ext4_mark_inode_dirty(handle, inode);
4715	if (unlikely(ret))
4716		goto out_handle;
 
4717	/* Zero out partial block at the edges of the range */
4718	ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4719	if (ret >= 0)
4720		ext4_update_inode_fsync_trans(handle, inode, 1);
4721
4722	if (file->f_flags & O_SYNC)
4723		ext4_handle_sync(handle);
4724
4725out_handle:
4726	ext4_journal_stop(handle);
4727out_mutex:
4728	inode_unlock(inode);
4729	return ret;
4730}
4731
4732/*
4733 * preallocate space for a file. This implements ext4's fallocate file
4734 * operation, which gets called from sys_fallocate system call.
4735 * For block-mapped files, posix_fallocate should fall back to the method
4736 * of writing zeroes to the required new blocks (the same behavior which is
4737 * expected for file systems which do not support fallocate() system call).
4738 */
4739long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4740{
4741	struct inode *inode = file_inode(file);
4742	loff_t new_size = 0;
4743	unsigned int max_blocks;
4744	int ret = 0;
4745	int flags;
4746	ext4_lblk_t lblk;
4747	unsigned int blkbits = inode->i_blkbits;
4748
4749	/*
4750	 * Encrypted inodes can't handle collapse range or insert
4751	 * range since we would need to re-encrypt blocks with a
4752	 * different IV or XTS tweak (which are based on the logical
4753	 * block number).
4754	 */
4755	if (IS_ENCRYPTED(inode) &&
4756	    (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4757		return -EOPNOTSUPP;
4758
4759	/* Return error if mode is not supported */
4760	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4761		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4762		     FALLOC_FL_INSERT_RANGE))
4763		return -EOPNOTSUPP;
4764
4765	inode_lock(inode);
 
 
4766	ret = ext4_convert_inline_data(inode);
4767	inode_unlock(inode);
4768	if (ret)
4769		goto exit;
4770
4771	if (mode & FALLOC_FL_PUNCH_HOLE) {
4772		ret = ext4_punch_hole(file, offset, len);
4773		goto exit;
4774	}
4775
4776	if (mode & FALLOC_FL_COLLAPSE_RANGE) {
4777		ret = ext4_collapse_range(file, offset, len);
4778		goto exit;
4779	}
4780
4781	if (mode & FALLOC_FL_INSERT_RANGE) {
4782		ret = ext4_insert_range(file, offset, len);
4783		goto exit;
4784	}
4785
4786	if (mode & FALLOC_FL_ZERO_RANGE) {
4787		ret = ext4_zero_range(file, offset, len, mode);
4788		goto exit;
4789	}
4790	trace_ext4_fallocate_enter(inode, offset, len, mode);
4791	lblk = offset >> blkbits;
4792
4793	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4794	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4795
4796	inode_lock(inode);
4797
4798	/*
4799	 * We only support preallocation for extent-based files only
4800	 */
4801	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4802		ret = -EOPNOTSUPP;
4803		goto out;
4804	}
4805
4806	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4807	    (offset + len > inode->i_size ||
4808	     offset + len > EXT4_I(inode)->i_disksize)) {
4809		new_size = offset + len;
4810		ret = inode_newsize_ok(inode, new_size);
4811		if (ret)
4812			goto out;
4813	}
4814
4815	/* Wait all existing dio workers, newcomers will block on i_rwsem */
4816	inode_dio_wait(inode);
4817
4818	ret = file_modified(file);
4819	if (ret)
4820		goto out;
4821
4822	ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4823	if (ret)
4824		goto out;
4825
4826	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4827		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
4828					EXT4_I(inode)->i_sync_tid);
4829	}
4830out:
4831	inode_unlock(inode);
4832	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4833exit:
4834	return ret;
4835}
4836
4837/*
4838 * This function convert a range of blocks to written extents
4839 * The caller of this function will pass the start offset and the size.
4840 * all unwritten extents within this range will be converted to
4841 * written extents.
4842 *
4843 * This function is called from the direct IO end io call back
4844 * function, to convert the fallocated extents after IO is completed.
4845 * Returns 0 on success.
4846 */
4847int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4848				   loff_t offset, ssize_t len)
4849{
4850	unsigned int max_blocks;
4851	int ret = 0, ret2 = 0, ret3 = 0;
4852	struct ext4_map_blocks map;
4853	unsigned int blkbits = inode->i_blkbits;
4854	unsigned int credits = 0;
4855
4856	map.m_lblk = offset >> blkbits;
4857	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4858
4859	if (!handle) {
4860		/*
4861		 * credits to insert 1 extent into extent tree
4862		 */
4863		credits = ext4_chunk_trans_blocks(inode, max_blocks);
4864	}
4865	while (ret >= 0 && ret < max_blocks) {
4866		map.m_lblk += ret;
4867		map.m_len = (max_blocks -= ret);
4868		if (credits) {
4869			handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4870						    credits);
4871			if (IS_ERR(handle)) {
4872				ret = PTR_ERR(handle);
4873				break;
4874			}
4875		}
4876		ret = ext4_map_blocks(handle, inode, &map,
4877				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4878		if (ret <= 0)
4879			ext4_warning(inode->i_sb,
4880				     "inode #%lu: block %u: len %u: "
4881				     "ext4_ext_map_blocks returned %d",
4882				     inode->i_ino, map.m_lblk,
4883				     map.m_len, ret);
4884		ret2 = ext4_mark_inode_dirty(handle, inode);
4885		if (credits) {
4886			ret3 = ext4_journal_stop(handle);
4887			if (unlikely(ret3))
4888				ret2 = ret3;
4889		}
4890
4891		if (ret <= 0 || ret2)
4892			break;
4893	}
4894	return ret > 0 ? ret2 : ret;
4895}
4896
4897int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4898{
4899	int ret = 0, err = 0;
4900	struct ext4_io_end_vec *io_end_vec;
4901
4902	/*
4903	 * This is somewhat ugly but the idea is clear: When transaction is
4904	 * reserved, everything goes into it. Otherwise we rather start several
4905	 * smaller transactions for conversion of each extent separately.
4906	 */
4907	if (handle) {
4908		handle = ext4_journal_start_reserved(handle,
4909						     EXT4_HT_EXT_CONVERT);
4910		if (IS_ERR(handle))
4911			return PTR_ERR(handle);
4912	}
4913
4914	list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4915		ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4916						     io_end_vec->offset,
4917						     io_end_vec->size);
4918		if (ret)
4919			break;
4920	}
4921
4922	if (handle)
4923		err = ext4_journal_stop(handle);
4924
4925	return ret < 0 ? ret : err;
4926}
4927
4928static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)
4929{
4930	__u64 physical = 0;
4931	__u64 length = 0;
4932	int blockbits = inode->i_sb->s_blocksize_bits;
4933	int error = 0;
4934	u16 iomap_type;
4935
4936	/* in-inode? */
4937	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4938		struct ext4_iloc iloc;
4939		int offset;	/* offset of xattr in inode */
4940
4941		error = ext4_get_inode_loc(inode, &iloc);
4942		if (error)
4943			return error;
4944		physical = (__u64)iloc.bh->b_blocknr << blockbits;
4945		offset = EXT4_GOOD_OLD_INODE_SIZE +
4946				EXT4_I(inode)->i_extra_isize;
4947		physical += offset;
4948		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4949		brelse(iloc.bh);
4950		iomap_type = IOMAP_INLINE;
4951	} else if (EXT4_I(inode)->i_file_acl) { /* external block */
4952		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4953		length = inode->i_sb->s_blocksize;
4954		iomap_type = IOMAP_MAPPED;
4955	} else {
4956		/* no in-inode or external block for xattr, so return -ENOENT */
4957		error = -ENOENT;
4958		goto out;
4959	}
4960
4961	iomap->addr = physical;
4962	iomap->offset = 0;
4963	iomap->length = length;
4964	iomap->type = iomap_type;
4965	iomap->flags = 0;
4966out:
4967	return error;
4968}
4969
4970static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,
4971				  loff_t length, unsigned flags,
4972				  struct iomap *iomap, struct iomap *srcmap)
4973{
4974	int error;
4975
4976	error = ext4_iomap_xattr_fiemap(inode, iomap);
4977	if (error == 0 && (offset >= iomap->length))
4978		error = -ENOENT;
4979	return error;
4980}
4981
4982static const struct iomap_ops ext4_iomap_xattr_ops = {
4983	.iomap_begin		= ext4_iomap_xattr_begin,
4984};
4985
4986static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
4987{
4988	u64 maxbytes;
4989
4990	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4991		maxbytes = inode->i_sb->s_maxbytes;
4992	else
4993		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
4994
4995	if (*len == 0)
4996		return -EINVAL;
4997	if (start > maxbytes)
4998		return -EFBIG;
4999
5000	/*
5001	 * Shrink request scope to what the fs can actually handle.
5002	 */
5003	if (*len > maxbytes || (maxbytes - *len) < start)
5004		*len = maxbytes - start;
5005	return 0;
5006}
5007
5008int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5009		u64 start, u64 len)
5010{
5011	int error = 0;
5012
5013	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5014		error = ext4_ext_precache(inode);
5015		if (error)
5016			return error;
5017		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5018	}
5019
5020	/*
5021	 * For bitmap files the maximum size limit could be smaller than
5022	 * s_maxbytes, so check len here manually instead of just relying on the
5023	 * generic check.
5024	 */
5025	error = ext4_fiemap_check_ranges(inode, start, &len);
5026	if (error)
5027		return error;
5028
5029	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5030		fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
5031		return iomap_fiemap(inode, fieinfo, start, len,
5032				    &ext4_iomap_xattr_ops);
5033	}
5034
5035	return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);
5036}
5037
5038int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
5039		      __u64 start, __u64 len)
5040{
5041	ext4_lblk_t start_blk, len_blks;
5042	__u64 last_blk;
5043	int error = 0;
5044
5045	if (ext4_has_inline_data(inode)) {
5046		int has_inline;
5047
5048		down_read(&EXT4_I(inode)->xattr_sem);
5049		has_inline = ext4_has_inline_data(inode);
5050		up_read(&EXT4_I(inode)->xattr_sem);
5051		if (has_inline)
5052			return 0;
5053	}
5054
5055	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5056		error = ext4_ext_precache(inode);
5057		if (error)
5058			return error;
5059		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5060	}
5061
5062	error = fiemap_prep(inode, fieinfo, start, &len, 0);
5063	if (error)
5064		return error;
5065
5066	error = ext4_fiemap_check_ranges(inode, start, &len);
5067	if (error)
5068		return error;
5069
5070	start_blk = start >> inode->i_sb->s_blocksize_bits;
5071	last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5072	if (last_blk >= EXT_MAX_BLOCKS)
5073		last_blk = EXT_MAX_BLOCKS-1;
5074	len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5075
5076	/*
5077	 * Walk the extent tree gathering extent information
5078	 * and pushing extents back to the user.
5079	 */
5080	return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
5081}
5082
5083/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5084 * ext4_ext_shift_path_extents:
5085 * Shift the extents of a path structure lying between path[depth].p_ext
5086 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5087 * if it is right shift or left shift operation.
5088 */
5089static int
5090ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5091			    struct inode *inode, handle_t *handle,
5092			    enum SHIFT_DIRECTION SHIFT)
5093{
5094	int depth, err = 0;
5095	struct ext4_extent *ex_start, *ex_last;
5096	bool update = false;
5097	int credits, restart_credits;
5098	depth = path->p_depth;
5099
5100	while (depth >= 0) {
5101		if (depth == path->p_depth) {
5102			ex_start = path[depth].p_ext;
5103			if (!ex_start)
5104				return -EFSCORRUPTED;
5105
5106			ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5107			/* leaf + sb + inode */
5108			credits = 3;
5109			if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
5110				update = true;
5111				/* extent tree + sb + inode */
5112				credits = depth + 2;
5113			}
5114
5115			restart_credits = ext4_writepage_trans_blocks(inode);
5116			err = ext4_datasem_ensure_credits(handle, inode, credits,
5117					restart_credits, 0);
5118			if (err) {
5119				if (err > 0)
5120					err = -EAGAIN;
5121				goto out;
5122			}
5123
5124			err = ext4_ext_get_access(handle, inode, path + depth);
5125			if (err)
5126				goto out;
5127
 
 
 
5128			while (ex_start <= ex_last) {
5129				if (SHIFT == SHIFT_LEFT) {
5130					le32_add_cpu(&ex_start->ee_block,
5131						-shift);
5132					/* Try to merge to the left. */
5133					if ((ex_start >
5134					    EXT_FIRST_EXTENT(path[depth].p_hdr))
5135					    &&
5136					    ext4_ext_try_to_merge_right(inode,
5137					    path, ex_start - 1))
5138						ex_last--;
5139					else
5140						ex_start++;
5141				} else {
5142					le32_add_cpu(&ex_last->ee_block, shift);
5143					ext4_ext_try_to_merge_right(inode, path,
5144						ex_last);
5145					ex_last--;
5146				}
5147			}
5148			err = ext4_ext_dirty(handle, inode, path + depth);
5149			if (err)
5150				goto out;
5151
5152			if (--depth < 0 || !update)
5153				break;
5154		}
5155
5156		/* Update index too */
5157		err = ext4_ext_get_access(handle, inode, path + depth);
5158		if (err)
5159			goto out;
5160
5161		if (SHIFT == SHIFT_LEFT)
5162			le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5163		else
5164			le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5165		err = ext4_ext_dirty(handle, inode, path + depth);
5166		if (err)
5167			goto out;
5168
5169		/* we are done if current index is not a starting index */
5170		if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5171			break;
5172
5173		depth--;
5174	}
5175
5176out:
5177	return err;
5178}
5179
5180/*
5181 * ext4_ext_shift_extents:
5182 * All the extents which lies in the range from @start to the last allocated
5183 * block for the @inode are shifted either towards left or right (depending
5184 * upon @SHIFT) by @shift blocks.
5185 * On success, 0 is returned, error otherwise.
5186 */
5187static int
5188ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5189		       ext4_lblk_t start, ext4_lblk_t shift,
5190		       enum SHIFT_DIRECTION SHIFT)
5191{
5192	struct ext4_ext_path *path;
5193	int ret = 0, depth;
5194	struct ext4_extent *extent;
5195	ext4_lblk_t stop, *iterator, ex_start, ex_end;
5196	ext4_lblk_t tmp = EXT_MAX_BLOCKS;
5197
5198	/* Let path point to the last extent */
5199	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5200				EXT4_EX_NOCACHE);
5201	if (IS_ERR(path))
5202		return PTR_ERR(path);
5203
5204	depth = path->p_depth;
5205	extent = path[depth].p_ext;
5206	if (!extent)
5207		goto out;
5208
5209	stop = le32_to_cpu(extent->ee_block);
5210
5211       /*
5212	* For left shifts, make sure the hole on the left is big enough to
5213	* accommodate the shift.  For right shifts, make sure the last extent
5214	* won't be shifted beyond EXT_MAX_BLOCKS.
5215	*/
5216	if (SHIFT == SHIFT_LEFT) {
5217		path = ext4_find_extent(inode, start - 1, path,
5218					EXT4_EX_NOCACHE);
5219		if (IS_ERR(path))
5220			return PTR_ERR(path);
5221		depth = path->p_depth;
5222		extent =  path[depth].p_ext;
5223		if (extent) {
5224			ex_start = le32_to_cpu(extent->ee_block);
5225			ex_end = le32_to_cpu(extent->ee_block) +
5226				ext4_ext_get_actual_len(extent);
5227		} else {
5228			ex_start = 0;
5229			ex_end = 0;
5230		}
5231
5232		if ((start == ex_start && shift > ex_start) ||
5233		    (shift > start - ex_end)) {
5234			ret = -EINVAL;
5235			goto out;
5236		}
5237	} else {
5238		if (shift > EXT_MAX_BLOCKS -
5239		    (stop + ext4_ext_get_actual_len(extent))) {
5240			ret = -EINVAL;
5241			goto out;
5242		}
5243	}
5244
5245	/*
5246	 * In case of left shift, iterator points to start and it is increased
5247	 * till we reach stop. In case of right shift, iterator points to stop
5248	 * and it is decreased till we reach start.
5249	 */
5250again:
5251	ret = 0;
5252	if (SHIFT == SHIFT_LEFT)
5253		iterator = &start;
5254	else
5255		iterator = &stop;
5256
5257	if (tmp != EXT_MAX_BLOCKS)
5258		*iterator = tmp;
5259
5260	/*
5261	 * Its safe to start updating extents.  Start and stop are unsigned, so
5262	 * in case of right shift if extent with 0 block is reached, iterator
5263	 * becomes NULL to indicate the end of the loop.
5264	 */
5265	while (iterator && start <= stop) {
5266		path = ext4_find_extent(inode, *iterator, path,
5267					EXT4_EX_NOCACHE);
5268		if (IS_ERR(path))
5269			return PTR_ERR(path);
5270		depth = path->p_depth;
5271		extent = path[depth].p_ext;
5272		if (!extent) {
5273			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5274					 (unsigned long) *iterator);
5275			return -EFSCORRUPTED;
5276		}
5277		if (SHIFT == SHIFT_LEFT && *iterator >
5278		    le32_to_cpu(extent->ee_block)) {
5279			/* Hole, move to the next extent */
5280			if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5281				path[depth].p_ext++;
5282			} else {
5283				*iterator = ext4_ext_next_allocated_block(path);
5284				continue;
5285			}
5286		}
5287
5288		tmp = *iterator;
5289		if (SHIFT == SHIFT_LEFT) {
5290			extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5291			*iterator = le32_to_cpu(extent->ee_block) +
5292					ext4_ext_get_actual_len(extent);
5293		} else {
5294			extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5295			if (le32_to_cpu(extent->ee_block) > start)
5296				*iterator = le32_to_cpu(extent->ee_block) - 1;
5297			else if (le32_to_cpu(extent->ee_block) == start)
 
5298				iterator = NULL;
5299			else {
5300				extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5301				while (le32_to_cpu(extent->ee_block) >= start)
5302					extent--;
5303
5304				if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))
5305					break;
5306
5307				extent++;
5308				iterator = NULL;
5309			}
5310			path[depth].p_ext = extent;
5311		}
5312		ret = ext4_ext_shift_path_extents(path, shift, inode,
5313				handle, SHIFT);
5314		/* iterator can be NULL which means we should break */
5315		if (ret == -EAGAIN)
5316			goto again;
5317		if (ret)
5318			break;
5319	}
5320out:
5321	ext4_free_ext_path(path);
 
5322	return ret;
5323}
5324
5325/*
5326 * ext4_collapse_range:
5327 * This implements the fallocate's collapse range functionality for ext4
5328 * Returns: 0 and non-zero on error.
5329 */
5330static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)
5331{
5332	struct inode *inode = file_inode(file);
5333	struct super_block *sb = inode->i_sb;
5334	struct address_space *mapping = inode->i_mapping;
5335	ext4_lblk_t punch_start, punch_stop;
5336	handle_t *handle;
5337	unsigned int credits;
5338	loff_t new_size, ioffset;
5339	int ret;
5340
5341	/*
5342	 * We need to test this early because xfstests assumes that a
5343	 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5344	 * system does not support collapse range.
5345	 */
5346	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5347		return -EOPNOTSUPP;
5348
5349	/* Collapse range works only on fs cluster size aligned regions. */
5350	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5351		return -EINVAL;
5352
5353	trace_ext4_collapse_range(inode, offset, len);
5354
5355	punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5356	punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5357
 
 
 
 
 
 
 
5358	inode_lock(inode);
5359	/*
5360	 * There is no need to overlap collapse range with EOF, in which case
5361	 * it is effectively a truncate operation
5362	 */
5363	if (offset + len >= inode->i_size) {
5364		ret = -EINVAL;
5365		goto out_mutex;
5366	}
5367
5368	/* Currently just for extent based files */
5369	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5370		ret = -EOPNOTSUPP;
5371		goto out_mutex;
5372	}
5373
5374	/* Wait for existing dio to complete */
5375	inode_dio_wait(inode);
5376
5377	ret = file_modified(file);
5378	if (ret)
5379		goto out_mutex;
5380
5381	/*
5382	 * Prevent page faults from reinstantiating pages we have released from
5383	 * page cache.
5384	 */
5385	filemap_invalidate_lock(mapping);
5386
5387	ret = ext4_break_layouts(inode);
5388	if (ret)
5389		goto out_mmap;
5390
5391	/*
5392	 * Need to round down offset to be aligned with page size boundary
5393	 * for page size > block size.
5394	 */
5395	ioffset = round_down(offset, PAGE_SIZE);
5396	/*
5397	 * Write tail of the last page before removed range since it will get
5398	 * removed from the page cache below.
5399	 */
5400	ret = filemap_write_and_wait_range(mapping, ioffset, offset);
5401	if (ret)
5402		goto out_mmap;
5403	/*
5404	 * Write data that will be shifted to preserve them when discarding
5405	 * page cache below. We are also protected from pages becoming dirty
5406	 * by i_rwsem and invalidate_lock.
5407	 */
5408	ret = filemap_write_and_wait_range(mapping, offset + len,
5409					   LLONG_MAX);
5410	if (ret)
5411		goto out_mmap;
5412	truncate_pagecache(inode, ioffset);
5413
5414	credits = ext4_writepage_trans_blocks(inode);
5415	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5416	if (IS_ERR(handle)) {
5417		ret = PTR_ERR(handle);
5418		goto out_mmap;
5419	}
5420	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5421
5422	down_write(&EXT4_I(inode)->i_data_sem);
5423	ext4_discard_preallocations(inode);
5424	ext4_es_remove_extent(inode, punch_start, EXT_MAX_BLOCKS - punch_start);
 
 
 
 
 
 
5425
5426	ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5427	if (ret) {
5428		up_write(&EXT4_I(inode)->i_data_sem);
5429		goto out_stop;
5430	}
5431	ext4_discard_preallocations(inode);
5432
5433	ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5434				     punch_stop - punch_start, SHIFT_LEFT);
5435	if (ret) {
5436		up_write(&EXT4_I(inode)->i_data_sem);
5437		goto out_stop;
5438	}
5439
5440	new_size = inode->i_size - len;
5441	i_size_write(inode, new_size);
5442	EXT4_I(inode)->i_disksize = new_size;
5443
5444	up_write(&EXT4_I(inode)->i_data_sem);
5445	if (IS_SYNC(inode))
5446		ext4_handle_sync(handle);
5447	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
5448	ret = ext4_mark_inode_dirty(handle, inode);
5449	ext4_update_inode_fsync_trans(handle, inode, 1);
5450
5451out_stop:
5452	ext4_journal_stop(handle);
5453out_mmap:
5454	filemap_invalidate_unlock(mapping);
5455out_mutex:
5456	inode_unlock(inode);
5457	return ret;
5458}
5459
5460/*
5461 * ext4_insert_range:
5462 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5463 * The data blocks starting from @offset to the EOF are shifted by @len
5464 * towards right to create a hole in the @inode. Inode size is increased
5465 * by len bytes.
5466 * Returns 0 on success, error otherwise.
5467 */
5468static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)
5469{
5470	struct inode *inode = file_inode(file);
5471	struct super_block *sb = inode->i_sb;
5472	struct address_space *mapping = inode->i_mapping;
5473	handle_t *handle;
5474	struct ext4_ext_path *path;
5475	struct ext4_extent *extent;
5476	ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5477	unsigned int credits, ee_len;
5478	int ret = 0, depth, split_flag = 0;
5479	loff_t ioffset;
5480
5481	/*
5482	 * We need to test this early because xfstests assumes that an
5483	 * insert range of (0, 1) will return EOPNOTSUPP if the file
5484	 * system does not support insert range.
5485	 */
5486	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5487		return -EOPNOTSUPP;
5488
5489	/* Insert range works only on fs cluster size aligned regions. */
5490	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5491		return -EINVAL;
5492
5493	trace_ext4_insert_range(inode, offset, len);
5494
5495	offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5496	len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5497
 
 
 
 
 
 
 
5498	inode_lock(inode);
5499	/* Currently just for extent based files */
5500	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5501		ret = -EOPNOTSUPP;
5502		goto out_mutex;
5503	}
5504
5505	/* Check whether the maximum file size would be exceeded */
5506	if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5507		ret = -EFBIG;
5508		goto out_mutex;
5509	}
5510
5511	/* Offset must be less than i_size */
5512	if (offset >= inode->i_size) {
5513		ret = -EINVAL;
5514		goto out_mutex;
5515	}
5516
5517	/* Wait for existing dio to complete */
5518	inode_dio_wait(inode);
5519
5520	ret = file_modified(file);
5521	if (ret)
5522		goto out_mutex;
5523
5524	/*
5525	 * Prevent page faults from reinstantiating pages we have released from
5526	 * page cache.
5527	 */
5528	filemap_invalidate_lock(mapping);
5529
5530	ret = ext4_break_layouts(inode);
5531	if (ret)
5532		goto out_mmap;
5533
5534	/*
5535	 * Need to round down to align start offset to page size boundary
5536	 * for page size > block size.
5537	 */
5538	ioffset = round_down(offset, PAGE_SIZE);
5539	/* Write out all dirty pages */
5540	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5541			LLONG_MAX);
5542	if (ret)
5543		goto out_mmap;
5544	truncate_pagecache(inode, ioffset);
5545
5546	credits = ext4_writepage_trans_blocks(inode);
5547	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5548	if (IS_ERR(handle)) {
5549		ret = PTR_ERR(handle);
5550		goto out_mmap;
5551	}
5552	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);
5553
5554	/* Expand file to avoid data loss if there is error while shifting */
5555	inode->i_size += len;
5556	EXT4_I(inode)->i_disksize += len;
5557	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
5558	ret = ext4_mark_inode_dirty(handle, inode);
5559	if (ret)
5560		goto out_stop;
5561
5562	down_write(&EXT4_I(inode)->i_data_sem);
5563	ext4_discard_preallocations(inode);
5564
5565	path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5566	if (IS_ERR(path)) {
5567		up_write(&EXT4_I(inode)->i_data_sem);
5568		ret = PTR_ERR(path);
5569		goto out_stop;
5570	}
5571
5572	depth = ext_depth(inode);
5573	extent = path[depth].p_ext;
5574	if (extent) {
5575		ee_start_lblk = le32_to_cpu(extent->ee_block);
5576		ee_len = ext4_ext_get_actual_len(extent);
5577
5578		/*
5579		 * If offset_lblk is not the starting block of extent, split
5580		 * the extent @offset_lblk
5581		 */
5582		if ((offset_lblk > ee_start_lblk) &&
5583				(offset_lblk < (ee_start_lblk + ee_len))) {
5584			if (ext4_ext_is_unwritten(extent))
5585				split_flag = EXT4_EXT_MARK_UNWRIT1 |
5586					EXT4_EXT_MARK_UNWRIT2;
5587			path = ext4_split_extent_at(handle, inode, path,
5588					offset_lblk, split_flag,
5589					EXT4_EX_NOCACHE |
5590					EXT4_GET_BLOCKS_PRE_IO |
5591					EXT4_GET_BLOCKS_METADATA_NOFAIL);
5592		}
5593
5594		if (IS_ERR(path)) {
 
 
5595			up_write(&EXT4_I(inode)->i_data_sem);
5596			ret = PTR_ERR(path);
5597			goto out_stop;
5598		}
 
 
 
5599	}
5600
5601	ext4_free_ext_path(path);
5602	ext4_es_remove_extent(inode, offset_lblk, EXT_MAX_BLOCKS - offset_lblk);
 
 
 
 
5603
5604	/*
5605	 * if offset_lblk lies in a hole which is at start of file, use
5606	 * ee_start_lblk to shift extents
5607	 */
5608	ret = ext4_ext_shift_extents(inode, handle,
5609		max(ee_start_lblk, offset_lblk), len_lblk, SHIFT_RIGHT);
 
5610
5611	up_write(&EXT4_I(inode)->i_data_sem);
5612	if (IS_SYNC(inode))
5613		ext4_handle_sync(handle);
5614	if (ret >= 0)
5615		ext4_update_inode_fsync_trans(handle, inode, 1);
5616
5617out_stop:
5618	ext4_journal_stop(handle);
5619out_mmap:
5620	filemap_invalidate_unlock(mapping);
5621out_mutex:
5622	inode_unlock(inode);
5623	return ret;
5624}
5625
5626/**
5627 * ext4_swap_extents() - Swap extents between two inodes
5628 * @handle: handle for this transaction
5629 * @inode1:	First inode
5630 * @inode2:	Second inode
5631 * @lblk1:	Start block for first inode
5632 * @lblk2:	Start block for second inode
5633 * @count:	Number of blocks to swap
5634 * @unwritten: Mark second inode's extents as unwritten after swap
5635 * @erp:	Pointer to save error value
5636 *
5637 * This helper routine does exactly what is promise "swap extents". All other
5638 * stuff such as page-cache locking consistency, bh mapping consistency or
5639 * extent's data copying must be performed by caller.
5640 * Locking:
5641 *		i_rwsem is held for both inodes
5642 * 		i_data_sem is locked for write for both inodes
5643 * Assumptions:
5644 *		All pages from requested range are locked for both inodes
5645 */
5646int
5647ext4_swap_extents(handle_t *handle, struct inode *inode1,
5648		  struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5649		  ext4_lblk_t count, int unwritten, int *erp)
5650{
5651	struct ext4_ext_path *path1 = NULL;
5652	struct ext4_ext_path *path2 = NULL;
5653	int replaced_count = 0;
5654
5655	BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5656	BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5657	BUG_ON(!inode_is_locked(inode1));
5658	BUG_ON(!inode_is_locked(inode2));
5659
5660	ext4_es_remove_extent(inode1, lblk1, count);
5661	ext4_es_remove_extent(inode2, lblk2, count);
 
 
 
 
5662
5663	while (count) {
5664		struct ext4_extent *ex1, *ex2, tmp_ex;
5665		ext4_lblk_t e1_blk, e2_blk;
5666		int e1_len, e2_len, len;
5667		int split = 0;
5668
5669		path1 = ext4_find_extent(inode1, lblk1, path1, EXT4_EX_NOCACHE);
5670		if (IS_ERR(path1)) {
5671			*erp = PTR_ERR(path1);
5672			goto errout;
 
 
 
5673		}
5674		path2 = ext4_find_extent(inode2, lblk2, path2, EXT4_EX_NOCACHE);
5675		if (IS_ERR(path2)) {
5676			*erp = PTR_ERR(path2);
5677			goto errout;
 
5678		}
5679		ex1 = path1[path1->p_depth].p_ext;
5680		ex2 = path2[path2->p_depth].p_ext;
5681		/* Do we have something to swap ? */
5682		if (unlikely(!ex2 || !ex1))
5683			goto errout;
5684
5685		e1_blk = le32_to_cpu(ex1->ee_block);
5686		e2_blk = le32_to_cpu(ex2->ee_block);
5687		e1_len = ext4_ext_get_actual_len(ex1);
5688		e2_len = ext4_ext_get_actual_len(ex2);
5689
5690		/* Hole handling */
5691		if (!in_range(lblk1, e1_blk, e1_len) ||
5692		    !in_range(lblk2, e2_blk, e2_len)) {
5693			ext4_lblk_t next1, next2;
5694
5695			/* if hole after extent, then go to next extent */
5696			next1 = ext4_ext_next_allocated_block(path1);
5697			next2 = ext4_ext_next_allocated_block(path2);
5698			/* If hole before extent, then shift to that extent */
5699			if (e1_blk > lblk1)
5700				next1 = e1_blk;
5701			if (e2_blk > lblk2)
5702				next2 = e2_blk;
5703			/* Do we have something to swap */
5704			if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5705				goto errout;
5706			/* Move to the rightest boundary */
5707			len = next1 - lblk1;
5708			if (len < next2 - lblk2)
5709				len = next2 - lblk2;
5710			if (len > count)
5711				len = count;
5712			lblk1 += len;
5713			lblk2 += len;
5714			count -= len;
5715			continue;
5716		}
5717
5718		/* Prepare left boundary */
5719		if (e1_blk < lblk1) {
5720			split = 1;
5721			path1 = ext4_force_split_extent_at(handle, inode1,
5722							   path1, lblk1, 0);
5723			if (IS_ERR(path1)) {
5724				*erp = PTR_ERR(path1);
5725				goto errout;
5726			}
5727		}
5728		if (e2_blk < lblk2) {
5729			split = 1;
5730			path2 = ext4_force_split_extent_at(handle, inode2,
5731							   path2, lblk2, 0);
5732			if (IS_ERR(path2)) {
5733				*erp = PTR_ERR(path2);
5734				goto errout;
5735			}
5736		}
5737		/* ext4_split_extent_at() may result in leaf extent split,
5738		 * path must to be revalidated. */
5739		if (split)
5740			continue;
5741
5742		/* Prepare right boundary */
5743		len = count;
5744		if (len > e1_blk + e1_len - lblk1)
5745			len = e1_blk + e1_len - lblk1;
5746		if (len > e2_blk + e2_len - lblk2)
5747			len = e2_blk + e2_len - lblk2;
5748
5749		if (len != e1_len) {
5750			split = 1;
5751			path1 = ext4_force_split_extent_at(handle, inode1,
5752							path1, lblk1 + len, 0);
5753			if (IS_ERR(path1)) {
5754				*erp = PTR_ERR(path1);
5755				goto errout;
5756			}
5757		}
5758		if (len != e2_len) {
5759			split = 1;
5760			path2 = ext4_force_split_extent_at(handle, inode2,
5761							path2, lblk2 + len, 0);
5762			if (IS_ERR(path2)) {
5763				*erp = PTR_ERR(path2);
5764				goto errout;
5765			}
5766		}
5767		/* ext4_split_extent_at() may result in leaf extent split,
5768		 * path must to be revalidated. */
5769		if (split)
5770			continue;
5771
5772		BUG_ON(e2_len != e1_len);
5773		*erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5774		if (unlikely(*erp))
5775			goto errout;
5776		*erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5777		if (unlikely(*erp))
5778			goto errout;
5779
5780		/* Both extents are fully inside boundaries. Swap it now */
5781		tmp_ex = *ex1;
5782		ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5783		ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5784		ex1->ee_len = cpu_to_le16(e2_len);
5785		ex2->ee_len = cpu_to_le16(e1_len);
5786		if (unwritten)
5787			ext4_ext_mark_unwritten(ex2);
5788		if (ext4_ext_is_unwritten(&tmp_ex))
5789			ext4_ext_mark_unwritten(ex1);
5790
5791		ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5792		ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5793		*erp = ext4_ext_dirty(handle, inode2, path2 +
5794				      path2->p_depth);
5795		if (unlikely(*erp))
5796			goto errout;
5797		*erp = ext4_ext_dirty(handle, inode1, path1 +
5798				      path1->p_depth);
5799		/*
5800		 * Looks scarry ah..? second inode already points to new blocks,
5801		 * and it was successfully dirtied. But luckily error may happen
5802		 * only due to journal error, so full transaction will be
5803		 * aborted anyway.
5804		 */
5805		if (unlikely(*erp))
5806			goto errout;
5807
5808		lblk1 += len;
5809		lblk2 += len;
5810		replaced_count += len;
5811		count -= len;
5812	}
5813
5814errout:
5815	ext4_free_ext_path(path1);
5816	ext4_free_ext_path(path2);
 
 
 
 
5817	return replaced_count;
5818}
5819
5820/*
5821 * ext4_clu_mapped - determine whether any block in a logical cluster has
5822 *                   been mapped to a physical cluster
5823 *
5824 * @inode - file containing the logical cluster
5825 * @lclu - logical cluster of interest
5826 *
5827 * Returns 1 if any block in the logical cluster is mapped, signifying
5828 * that a physical cluster has been allocated for it.  Otherwise,
5829 * returns 0.  Can also return negative error codes.  Derived from
5830 * ext4_ext_map_blocks().
5831 */
5832int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5833{
5834	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5835	struct ext4_ext_path *path;
5836	int depth, mapped = 0, err = 0;
5837	struct ext4_extent *extent;
5838	ext4_lblk_t first_lblk, first_lclu, last_lclu;
5839
5840	/*
5841	 * if data can be stored inline, the logical cluster isn't
5842	 * mapped - no physical clusters have been allocated, and the
5843	 * file has no extents
5844	 */
5845	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||
5846	    ext4_has_inline_data(inode))
5847		return 0;
5848
5849	/* search for the extent closest to the first block in the cluster */
5850	path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5851	if (IS_ERR(path))
5852		return PTR_ERR(path);
 
 
 
5853
5854	depth = ext_depth(inode);
5855
5856	/*
5857	 * A consistent leaf must not be empty.  This situation is possible,
5858	 * though, _during_ tree modification, and it's why an assert can't
5859	 * be put in ext4_find_extent().
5860	 */
5861	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5862		EXT4_ERROR_INODE(inode,
5863		    "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5864				 (unsigned long) EXT4_C2B(sbi, lclu),
5865				 depth, path[depth].p_block);
5866		err = -EFSCORRUPTED;
5867		goto out;
5868	}
5869
5870	extent = path[depth].p_ext;
5871
5872	/* can't be mapped if the extent tree is empty */
5873	if (extent == NULL)
5874		goto out;
5875
5876	first_lblk = le32_to_cpu(extent->ee_block);
5877	first_lclu = EXT4_B2C(sbi, first_lblk);
5878
5879	/*
5880	 * Three possible outcomes at this point - found extent spanning
5881	 * the target cluster, to the left of the target cluster, or to the
5882	 * right of the target cluster.  The first two cases are handled here.
5883	 * The last case indicates the target cluster is not mapped.
5884	 */
5885	if (lclu >= first_lclu) {
5886		last_lclu = EXT4_B2C(sbi, first_lblk +
5887				     ext4_ext_get_actual_len(extent) - 1);
5888		if (lclu <= last_lclu) {
5889			mapped = 1;
5890		} else {
5891			first_lblk = ext4_ext_next_allocated_block(path);
5892			first_lclu = EXT4_B2C(sbi, first_lblk);
5893			if (lclu == first_lclu)
5894				mapped = 1;
5895		}
5896	}
5897
5898out:
5899	ext4_free_ext_path(path);
 
5900
5901	return err ? err : mapped;
5902}
5903
5904/*
5905 * Updates physical block address and unwritten status of extent
5906 * starting at lblk start and of len. If such an extent doesn't exist,
5907 * this function splits the extent tree appropriately to create an
5908 * extent like this.  This function is called in the fast commit
5909 * replay path.  Returns 0 on success and error on failure.
5910 */
5911int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
5912			      int len, int unwritten, ext4_fsblk_t pblk)
5913{
5914	struct ext4_ext_path *path;
5915	struct ext4_extent *ex;
5916	int ret;
5917
5918	path = ext4_find_extent(inode, start, NULL, 0);
5919	if (IS_ERR(path))
5920		return PTR_ERR(path);
5921	ex = path[path->p_depth].p_ext;
5922	if (!ex) {
5923		ret = -EFSCORRUPTED;
5924		goto out;
5925	}
5926
5927	if (le32_to_cpu(ex->ee_block) != start ||
5928		ext4_ext_get_actual_len(ex) != len) {
5929		/* We need to split this extent to match our extent first */
5930		down_write(&EXT4_I(inode)->i_data_sem);
5931		path = ext4_force_split_extent_at(NULL, inode, path, start, 1);
5932		up_write(&EXT4_I(inode)->i_data_sem);
5933		if (IS_ERR(path)) {
5934			ret = PTR_ERR(path);
5935			goto out;
5936		}
5937
5938		path = ext4_find_extent(inode, start, path, 0);
5939		if (IS_ERR(path))
5940			return PTR_ERR(path);
5941
5942		ex = path[path->p_depth].p_ext;
5943		WARN_ON(le32_to_cpu(ex->ee_block) != start);
5944
5945		if (ext4_ext_get_actual_len(ex) != len) {
5946			down_write(&EXT4_I(inode)->i_data_sem);
5947			path = ext4_force_split_extent_at(NULL, inode, path,
5948							  start + len, 1);
5949			up_write(&EXT4_I(inode)->i_data_sem);
5950			if (IS_ERR(path)) {
5951				ret = PTR_ERR(path);
5952				goto out;
5953			}
5954
5955			path = ext4_find_extent(inode, start, path, 0);
5956			if (IS_ERR(path))
5957				return PTR_ERR(path);
5958			ex = path[path->p_depth].p_ext;
5959		}
5960	}
5961	if (unwritten)
5962		ext4_ext_mark_unwritten(ex);
5963	else
5964		ext4_ext_mark_initialized(ex);
5965	ext4_ext_store_pblock(ex, pblk);
5966	down_write(&EXT4_I(inode)->i_data_sem);
5967	ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5968	up_write(&EXT4_I(inode)->i_data_sem);
5969out:
5970	ext4_free_ext_path(path);
5971	ext4_mark_inode_dirty(NULL, inode);
5972	return ret;
5973}
5974
5975/* Try to shrink the extent tree */
5976void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
5977{
5978	struct ext4_ext_path *path = NULL;
5979	struct ext4_extent *ex;
5980	ext4_lblk_t old_cur, cur = 0;
5981
5982	while (cur < end) {
5983		path = ext4_find_extent(inode, cur, NULL, 0);
5984		if (IS_ERR(path))
5985			return;
5986		ex = path[path->p_depth].p_ext;
5987		if (!ex) {
5988			ext4_free_ext_path(path);
5989			ext4_mark_inode_dirty(NULL, inode);
5990			return;
5991		}
5992		old_cur = cur;
5993		cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
5994		if (cur <= old_cur)
5995			cur = old_cur + 1;
5996		ext4_ext_try_to_merge(NULL, inode, path, ex);
5997		down_write(&EXT4_I(inode)->i_data_sem);
5998		ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
5999		up_write(&EXT4_I(inode)->i_data_sem);
6000		ext4_mark_inode_dirty(NULL, inode);
6001		ext4_free_ext_path(path);
6002	}
6003}
6004
6005/* Check if *cur is a hole and if it is, skip it */
6006static int skip_hole(struct inode *inode, ext4_lblk_t *cur)
6007{
6008	int ret;
6009	struct ext4_map_blocks map;
6010
6011	map.m_lblk = *cur;
6012	map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
6013
6014	ret = ext4_map_blocks(NULL, inode, &map, 0);
6015	if (ret < 0)
6016		return ret;
6017	if (ret != 0)
6018		return 0;
6019	*cur = *cur + map.m_len;
6020	return 0;
6021}
6022
6023/* Count number of blocks used by this inode and update i_blocks */
6024int ext4_ext_replay_set_iblocks(struct inode *inode)
6025{
6026	struct ext4_ext_path *path = NULL, *path2 = NULL;
6027	struct ext4_extent *ex;
6028	ext4_lblk_t cur = 0, end;
6029	int numblks = 0, i, ret = 0;
6030	ext4_fsblk_t cmp1, cmp2;
6031	struct ext4_map_blocks map;
6032
6033	/* Determin the size of the file first */
6034	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6035					EXT4_EX_NOCACHE);
6036	if (IS_ERR(path))
6037		return PTR_ERR(path);
6038	ex = path[path->p_depth].p_ext;
6039	if (!ex)
6040		goto out;
6041	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6042
6043	/* Count the number of data blocks */
6044	cur = 0;
6045	while (cur < end) {
6046		map.m_lblk = cur;
6047		map.m_len = end - cur;
6048		ret = ext4_map_blocks(NULL, inode, &map, 0);
6049		if (ret < 0)
6050			break;
6051		if (ret > 0)
6052			numblks += ret;
6053		cur = cur + map.m_len;
6054	}
6055
6056	/*
6057	 * Count the number of extent tree blocks. We do it by looking up
6058	 * two successive extents and determining the difference between
6059	 * their paths. When path is different for 2 successive extents
6060	 * we compare the blocks in the path at each level and increment
6061	 * iblocks by total number of differences found.
6062	 */
6063	cur = 0;
6064	ret = skip_hole(inode, &cur);
6065	if (ret < 0)
6066		goto out;
6067	path = ext4_find_extent(inode, cur, path, 0);
6068	if (IS_ERR(path))
6069		goto out;
6070	numblks += path->p_depth;
6071	while (cur < end) {
6072		path = ext4_find_extent(inode, cur, path, 0);
6073		if (IS_ERR(path))
6074			break;
6075		ex = path[path->p_depth].p_ext;
6076		if (!ex)
6077			goto cleanup;
6078
6079		cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
6080					ext4_ext_get_actual_len(ex));
6081		ret = skip_hole(inode, &cur);
6082		if (ret < 0)
6083			break;
6084
6085		path2 = ext4_find_extent(inode, cur, path2, 0);
6086		if (IS_ERR(path2))
6087			break;
6088
6089		for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
6090			cmp1 = cmp2 = 0;
6091			if (i <= path->p_depth)
6092				cmp1 = path[i].p_bh ?
6093					path[i].p_bh->b_blocknr : 0;
6094			if (i <= path2->p_depth)
6095				cmp2 = path2[i].p_bh ?
6096					path2[i].p_bh->b_blocknr : 0;
6097			if (cmp1 != cmp2 && cmp2 != 0)
6098				numblks++;
6099		}
6100	}
6101
6102out:
6103	inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
6104	ext4_mark_inode_dirty(NULL, inode);
6105cleanup:
6106	ext4_free_ext_path(path);
6107	ext4_free_ext_path(path2);
6108	return 0;
6109}
6110
6111int ext4_ext_clear_bb(struct inode *inode)
6112{
6113	struct ext4_ext_path *path = NULL;
6114	struct ext4_extent *ex;
6115	ext4_lblk_t cur = 0, end;
6116	int j, ret = 0;
6117	struct ext4_map_blocks map;
6118
6119	if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
6120		return 0;
6121
6122	/* Determin the size of the file first */
6123	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
6124					EXT4_EX_NOCACHE);
6125	if (IS_ERR(path))
6126		return PTR_ERR(path);
6127	ex = path[path->p_depth].p_ext;
6128	if (!ex)
6129		goto out;
6130	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
6131
6132	cur = 0;
6133	while (cur < end) {
6134		map.m_lblk = cur;
6135		map.m_len = end - cur;
6136		ret = ext4_map_blocks(NULL, inode, &map, 0);
6137		if (ret < 0)
6138			break;
6139		if (ret > 0) {
6140			path = ext4_find_extent(inode, map.m_lblk, path, 0);
6141			if (!IS_ERR(path)) {
6142				for (j = 0; j < path->p_depth; j++) {
6143					ext4_mb_mark_bb(inode->i_sb,
6144							path[j].p_block, 1, false);
6145					ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6146							0, path[j].p_block, 1, 1);
6147				}
6148			} else {
6149				path = NULL;
6150			}
6151			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, false);
6152			ext4_fc_record_regions(inode->i_sb, inode->i_ino,
6153					map.m_lblk, map.m_pblk, map.m_len, 1);
6154		}
6155		cur = cur + map.m_len;
6156	}
6157
6158out:
6159	ext4_free_ext_path(path);
6160	return 0;
6161}