1/*
   2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3 * Written by Alex Tomas <alex@clusterfs.com>
   4 *
   5 * Architecture independence:
   6 *   Copyright (c) 2005, Bull S.A.
   7 *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public Licens
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21 */
  22
  23/*
  24 * Extents support for EXT4
  25 *
  26 * TODO:
  27 *   - ext4*_error() should be used in some situations
  28 *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29 *   - smart tree reduction
  30 */
  31
  32#include <linux/module.h>
  33#include <linux/fs.h>
  34#include <linux/time.h>
  35#include <linux/jbd2.h>
  36#include <linux/highuid.h>
  37#include <linux/pagemap.h>
  38#include <linux/quotaops.h>
  39#include <linux/string.h>
  40#include <linux/slab.h>
  41#include <linux/falloc.h>
  42#include <asm/uaccess.h>
  43#include <linux/fiemap.h>
 
 
  44#include "ext4_jbd2.h"
  45#include "ext4_extents.h"
 
  46
  47#include <trace/events/ext4.h>
  48
  49static int ext4_split_extent(handle_t *handle,
  50				struct inode *inode,
  51				struct ext4_ext_path *path,
  52				struct ext4_map_blocks *map,
  53				int split_flag,
  54				int flags);
  55
  56static int ext4_ext_truncate_extend_restart(handle_t *handle,
  57					    struct inode *inode,
  58					    int needed)
 
 
 
  59{
  60	int err;
 
 
  61
  62	if (!ext4_handle_valid(handle))
  63		return 0;
  64	if (handle->h_buffer_credits > needed)
 
 
 
 
 
 
 
 
 
 
 
 
  65		return 0;
  66	err = ext4_journal_extend(handle, needed);
  67	if (err <= 0)
  68		return err;
  69	err = ext4_truncate_restart_trans(handle, inode, needed);
  70	if (err == 0)
  71		err = -EAGAIN;
  72
  73	return err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  74}
  75
  76/*
  77 * could return:
  78 *  - EROFS
  79 *  - ENOMEM
  80 */
  81static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
  82				struct ext4_ext_path *path)
  83{
 
 
  84	if (path->p_bh) {
  85		/* path points to block */
  86		return ext4_journal_get_write_access(handle, path->p_bh);
 
 
 
 
 
 
 
 
 
 
  87	}
  88	/* path points to leaf/index in inode body */
  89	/* we use in-core data, no need to protect them */
  90	return 0;
  91}
  92
  93/*
  94 * could return:
  95 *  - EROFS
  96 *  - ENOMEM
  97 *  - EIO
  98 */
  99static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
 100				struct ext4_ext_path *path)
 
 101{
 102	int err;
 
 
 103	if (path->p_bh) {
 
 104		/* path points to block */
 105		err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
 
 
 
 
 106	} else {
 107		/* path points to leaf/index in inode body */
 108		err = ext4_mark_inode_dirty(handle, inode);
 109	}
 110	return err;
 111}
 112
 
 
 
 113static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 114			      struct ext4_ext_path *path,
 115			      ext4_lblk_t block)
 116{
 117	int depth;
 118
 119	if (path) {
 
 120		struct ext4_extent *ex;
 121		depth = path->p_depth;
 122
 123		/*
 124		 * Try to predict block placement assuming that we are
 125		 * filling in a file which will eventually be
 126		 * non-sparse --- i.e., in the case of libbfd writing
 127		 * an ELF object sections out-of-order but in a way
 128		 * the eventually results in a contiguous object or
 129		 * executable file, or some database extending a table
 130		 * space file.  However, this is actually somewhat
 131		 * non-ideal if we are writing a sparse file such as
 132		 * qemu or KVM writing a raw image file that is going
 133		 * to stay fairly sparse, since it will end up
 134		 * fragmenting the file system's free space.  Maybe we
 135		 * should have some hueristics or some way to allow
 136		 * userspace to pass a hint to file system,
 137		 * especially if the latter case turns out to be
 138		 * common.
 139		 */
 140		ex = path[depth].p_ext;
 141		if (ex) {
 142			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 143			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 144
 145			if (block > ext_block)
 146				return ext_pblk + (block - ext_block);
 147			else
 148				return ext_pblk - (ext_block - block);
 149		}
 150
 151		/* it looks like index is empty;
 152		 * try to find starting block from index itself */
 153		if (path[depth].p_bh)
 154			return path[depth].p_bh->b_blocknr;
 155	}
 156
 157	/* OK. use inode's group */
 158	return ext4_inode_to_goal_block(inode);
 159}
 160
 161/*
 162 * Allocation for a meta data block
 163 */
 164static ext4_fsblk_t
 165ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 166			struct ext4_ext_path *path,
 167			struct ext4_extent *ex, int *err, unsigned int flags)
 168{
 169	ext4_fsblk_t goal, newblock;
 170
 171	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 172	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 173					NULL, err);
 174	return newblock;
 175}
 176
 177static inline int ext4_ext_space_block(struct inode *inode, int check)
 178{
 179	int size;
 180
 181	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 182			/ sizeof(struct ext4_extent);
 183	if (!check) {
 184#ifdef AGGRESSIVE_TEST
 185		if (size > 6)
 186			size = 6;
 187#endif
 188	}
 189	return size;
 190}
 191
 192static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 193{
 194	int size;
 195
 196	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 197			/ sizeof(struct ext4_extent_idx);
 198	if (!check) {
 199#ifdef AGGRESSIVE_TEST
 200		if (size > 5)
 201			size = 5;
 202#endif
 203	}
 204	return size;
 205}
 206
 207static inline int ext4_ext_space_root(struct inode *inode, int check)
 208{
 209	int size;
 210
 211	size = sizeof(EXT4_I(inode)->i_data);
 212	size -= sizeof(struct ext4_extent_header);
 213	size /= sizeof(struct ext4_extent);
 214	if (!check) {
 215#ifdef AGGRESSIVE_TEST
 216		if (size > 3)
 217			size = 3;
 218#endif
 219	}
 220	return size;
 221}
 222
 223static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 224{
 225	int size;
 226
 227	size = sizeof(EXT4_I(inode)->i_data);
 228	size -= sizeof(struct ext4_extent_header);
 229	size /= sizeof(struct ext4_extent_idx);
 230	if (!check) {
 231#ifdef AGGRESSIVE_TEST
 232		if (size > 4)
 233			size = 4;
 234#endif
 235	}
 236	return size;
 237}
 238
 239/*
 240 * Calculate the number of metadata blocks needed
 241 * to allocate @blocks
 242 * Worse case is one block per extent
 243 */
 244int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 245{
 246	struct ext4_inode_info *ei = EXT4_I(inode);
 247	int idxs, num = 0;
 248
 249	idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 250		/ sizeof(struct ext4_extent_idx));
 251
 252	/*
 253	 * If the new delayed allocation block is contiguous with the
 254	 * previous da block, it can share index blocks with the
 255	 * previous block, so we only need to allocate a new index
 256	 * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 257	 * an additional index block, and at ldxs**3 blocks, yet
 258	 * another index blocks.
 259	 */
 260	if (ei->i_da_metadata_calc_len &&
 261	    ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 262		if ((ei->i_da_metadata_calc_len % idxs) == 0)
 263			num++;
 264		if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 265			num++;
 266		if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 267			num++;
 268			ei->i_da_metadata_calc_len = 0;
 269		} else
 270			ei->i_da_metadata_calc_len++;
 271		ei->i_da_metadata_calc_last_lblock++;
 272		return num;
 273	}
 274
 275	/*
 276	 * In the worst case we need a new set of index blocks at
 277	 * every level of the inode's extent tree.
 278	 */
 279	ei->i_da_metadata_calc_len = 1;
 280	ei->i_da_metadata_calc_last_lblock = lblock;
 281	return ext_depth(inode) + 1;
 282}
 283
 284static int
 285ext4_ext_max_entries(struct inode *inode, int depth)
 286{
 287	int max;
 288
 289	if (depth == ext_depth(inode)) {
 290		if (depth == 0)
 291			max = ext4_ext_space_root(inode, 1);
 292		else
 293			max = ext4_ext_space_root_idx(inode, 1);
 294	} else {
 295		if (depth == 0)
 296			max = ext4_ext_space_block(inode, 1);
 297		else
 298			max = ext4_ext_space_block_idx(inode, 1);
 299	}
 300
 301	return max;
 302}
 303
 304static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 305{
 306	ext4_fsblk_t block = ext4_ext_pblock(ext);
 307	int len = ext4_ext_get_actual_len(ext);
 
 308
 309	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 
 
 
 
 
 
 
 310}
 311
 312static int ext4_valid_extent_idx(struct inode *inode,
 313				struct ext4_extent_idx *ext_idx)
 314{
 315	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 316
 317	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 318}
 319
 320static int ext4_valid_extent_entries(struct inode *inode,
 321				struct ext4_extent_header *eh,
 322				int depth)
 
 323{
 324	struct ext4_extent *ext;
 325	struct ext4_extent_idx *ext_idx;
 326	unsigned short entries;
 
 
 
 327	if (eh->eh_entries == 0)
 328		return 1;
 329
 330	entries = le16_to_cpu(eh->eh_entries);
 331
 332	if (depth == 0) {
 333		/* leaf entries */
 334		ext = EXT_FIRST_EXTENT(eh);
 
 
 
 
 
 
 
 
 335		while (entries) {
 336			if (!ext4_valid_extent(inode, ext))
 337				return 0;
 
 
 
 
 
 
 
 
 338			ext++;
 339			entries--;
 340		}
 341	} else {
 342		ext_idx = EXT_FIRST_INDEX(eh);
 
 
 
 
 
 
 
 
 343		while (entries) {
 344			if (!ext4_valid_extent_idx(inode, ext_idx))
 345				return 0;
 
 
 
 
 
 
 
 346			ext_idx++;
 347			entries--;
 
 348		}
 349	}
 350	return 1;
 351}
 352
 353static int __ext4_ext_check(const char *function, unsigned int line,
 354			    struct inode *inode, struct ext4_extent_header *eh,
 355			    int depth)
 356{
 357	const char *error_msg;
 358	int max = 0;
 359
 360	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 361		error_msg = "invalid magic";
 362		goto corrupted;
 363	}
 364	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 365		error_msg = "unexpected eh_depth";
 366		goto corrupted;
 367	}
 368	if (unlikely(eh->eh_max == 0)) {
 369		error_msg = "invalid eh_max";
 370		goto corrupted;
 371	}
 372	max = ext4_ext_max_entries(inode, depth);
 373	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 374		error_msg = "too large eh_max";
 375		goto corrupted;
 376	}
 377	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 378		error_msg = "invalid eh_entries";
 379		goto corrupted;
 380	}
 381	if (!ext4_valid_extent_entries(inode, eh, depth)) {
 
 
 
 
 382		error_msg = "invalid extent entries";
 383		goto corrupted;
 384	}
 
 
 
 
 
 
 
 
 
 
 
 385	return 0;
 386
 387corrupted:
 388	ext4_error_inode(inode, function, line, 0,
 389			"bad header/extent: %s - magic %x, "
 390			"entries %u, max %u(%u), depth %u(%u)",
 391			error_msg, le16_to_cpu(eh->eh_magic),
 392			le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 393			max, le16_to_cpu(eh->eh_depth), depth);
 394
 395	return -EIO;
 
 396}
 397
 398#define ext4_ext_check(inode, eh, depth)	\
 399	__ext4_ext_check(__func__, __LINE__, inode, eh, depth)
 400
 401int ext4_ext_check_inode(struct inode *inode)
 402{
 403	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 404}
 405
 406#ifdef EXT_DEBUG
 407static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 408{
 409	int k, l = path->p_depth;
 410
 411	ext_debug("path:");
 412	for (k = 0; k <= l; k++, path++) {
 413		if (path->p_idx) {
 414		  ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 415			    ext4_idx_pblock(path->p_idx));
 
 416		} else if (path->p_ext) {
 417			ext_debug("  %d:[%d]%d:%llu ",
 418				  le32_to_cpu(path->p_ext->ee_block),
 419				  ext4_ext_is_uninitialized(path->p_ext),
 420				  ext4_ext_get_actual_len(path->p_ext),
 421				  ext4_ext_pblock(path->p_ext));
 422		} else
 423			ext_debug("  []");
 424	}
 425	ext_debug("\n");
 426}
 427
 428static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 429{
 430	int depth = ext_depth(inode);
 431	struct ext4_extent_header *eh;
 432	struct ext4_extent *ex;
 433	int i;
 434
 435	if (!path)
 436		return;
 437
 438	eh = path[depth].p_hdr;
 439	ex = EXT_FIRST_EXTENT(eh);
 440
 441	ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 442
 443	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 444		ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 445			  ext4_ext_is_uninitialized(ex),
 446			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 447	}
 448	ext_debug("\n");
 449}
 450
 451static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 452			ext4_fsblk_t newblock, int level)
 453{
 454	int depth = ext_depth(inode);
 455	struct ext4_extent *ex;
 456
 457	if (depth != level) {
 458		struct ext4_extent_idx *idx;
 459		idx = path[level].p_idx;
 460		while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 461			ext_debug("%d: move %d:%llu in new index %llu\n", level,
 462					le32_to_cpu(idx->ei_block),
 463					ext4_idx_pblock(idx),
 464					newblock);
 465			idx++;
 466		}
 467
 468		return;
 469	}
 470
 471	ex = path[depth].p_ext;
 472	while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 473		ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 474				le32_to_cpu(ex->ee_block),
 475				ext4_ext_pblock(ex),
 476				ext4_ext_is_uninitialized(ex),
 477				ext4_ext_get_actual_len(ex),
 478				newblock);
 479		ex++;
 480	}
 481}
 482
 483#else
 484#define ext4_ext_show_path(inode, path)
 485#define ext4_ext_show_leaf(inode, path)
 486#define ext4_ext_show_move(inode, path, newblock, level)
 487#endif
 488
 489void ext4_ext_drop_refs(struct ext4_ext_path *path)
 490{
 491	int depth = path->p_depth;
 492	int i;
 493
 494	for (i = 0; i <= depth; i++, path++)
 495		if (path->p_bh) {
 496			brelse(path->p_bh);
 497			path->p_bh = NULL;
 498		}
 499}
 500
 501/*
 502 * ext4_ext_binsearch_idx:
 503 * binary search for the closest index of the given block
 504 * the header must be checked before calling this
 505 */
 506static void
 507ext4_ext_binsearch_idx(struct inode *inode,
 508			struct ext4_ext_path *path, ext4_lblk_t block)
 509{
 510	struct ext4_extent_header *eh = path->p_hdr;
 511	struct ext4_extent_idx *r, *l, *m;
 512
 513
 514	ext_debug("binsearch for %u(idx):  ", block);
 515
 516	l = EXT_FIRST_INDEX(eh) + 1;
 517	r = EXT_LAST_INDEX(eh);
 518	while (l <= r) {
 519		m = l + (r - l) / 2;
 
 
 
 
 520		if (block < le32_to_cpu(m->ei_block))
 521			r = m - 1;
 522		else
 523			l = m + 1;
 524		ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 525				m, le32_to_cpu(m->ei_block),
 526				r, le32_to_cpu(r->ei_block));
 527	}
 528
 529	path->p_idx = l - 1;
 530	ext_debug("  -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
 531		  ext4_idx_pblock(path->p_idx));
 532
 533#ifdef CHECK_BINSEARCH
 534	{
 535		struct ext4_extent_idx *chix, *ix;
 536		int k;
 537
 538		chix = ix = EXT_FIRST_INDEX(eh);
 539		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 540		  if (k != 0 &&
 541		      le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 542				printk(KERN_DEBUG "k=%d, ix=0x%p, "
 543				       "first=0x%p\n", k,
 544				       ix, EXT_FIRST_INDEX(eh));
 545				printk(KERN_DEBUG "%u <= %u\n",
 546				       le32_to_cpu(ix->ei_block),
 547				       le32_to_cpu(ix[-1].ei_block));
 548			}
 549			BUG_ON(k && le32_to_cpu(ix->ei_block)
 550					   <= le32_to_cpu(ix[-1].ei_block));
 551			if (block < le32_to_cpu(ix->ei_block))
 552				break;
 553			chix = ix;
 554		}
 555		BUG_ON(chix != path->p_idx);
 556	}
 557#endif
 558
 559}
 560
 561/*
 562 * ext4_ext_binsearch:
 563 * binary search for closest extent of the given block
 564 * the header must be checked before calling this
 565 */
 566static void
 567ext4_ext_binsearch(struct inode *inode,
 568		struct ext4_ext_path *path, ext4_lblk_t block)
 569{
 570	struct ext4_extent_header *eh = path->p_hdr;
 571	struct ext4_extent *r, *l, *m;
 572
 573	if (eh->eh_entries == 0) {
 574		/*
 575		 * this leaf is empty:
 576		 * we get such a leaf in split/add case
 577		 */
 578		return;
 579	}
 580
 581	ext_debug("binsearch for %u:  ", block);
 582
 583	l = EXT_FIRST_EXTENT(eh) + 1;
 584	r = EXT_LAST_EXTENT(eh);
 585
 586	while (l <= r) {
 587		m = l + (r - l) / 2;
 
 
 
 
 588		if (block < le32_to_cpu(m->ee_block))
 589			r = m - 1;
 590		else
 591			l = m + 1;
 592		ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 593				m, le32_to_cpu(m->ee_block),
 594				r, le32_to_cpu(r->ee_block));
 595	}
 596
 597	path->p_ext = l - 1;
 598	ext_debug("  -> %d:%llu:[%d]%d ",
 599			le32_to_cpu(path->p_ext->ee_block),
 600			ext4_ext_pblock(path->p_ext),
 601			ext4_ext_is_uninitialized(path->p_ext),
 602			ext4_ext_get_actual_len(path->p_ext));
 603
 604#ifdef CHECK_BINSEARCH
 605	{
 606		struct ext4_extent *chex, *ex;
 607		int k;
 608
 609		chex = ex = EXT_FIRST_EXTENT(eh);
 610		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 611			BUG_ON(k && le32_to_cpu(ex->ee_block)
 612					  <= le32_to_cpu(ex[-1].ee_block));
 613			if (block < le32_to_cpu(ex->ee_block))
 614				break;
 615			chex = ex;
 616		}
 617		BUG_ON(chex != path->p_ext);
 618	}
 619#endif
 620
 621}
 622
 623int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 624{
 625	struct ext4_extent_header *eh;
 626
 627	eh = ext_inode_hdr(inode);
 628	eh->eh_depth = 0;
 629	eh->eh_entries = 0;
 630	eh->eh_magic = EXT4_EXT_MAGIC;
 631	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 
 632	ext4_mark_inode_dirty(handle, inode);
 633	ext4_ext_invalidate_cache(inode);
 634	return 0;
 635}
 636
 637struct ext4_ext_path *
 638ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 639					struct ext4_ext_path *path)
 640{
 641	struct ext4_extent_header *eh;
 642	struct buffer_head *bh;
 643	short int depth, i, ppos = 0, alloc = 0;
 
 
 
 
 
 644
 645	eh = ext_inode_hdr(inode);
 646	depth = ext_depth(inode);
 
 
 
 
 
 
 647
 648	/* account possible depth increase */
 
 
 
 
 
 
 649	if (!path) {
 650		path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 651				GFP_NOFS);
 652		if (!path)
 
 653			return ERR_PTR(-ENOMEM);
 654		alloc = 1;
 655	}
 656	path[0].p_hdr = eh;
 657	path[0].p_bh = NULL;
 658
 659	i = depth;
 
 
 660	/* walk through the tree */
 661	while (i) {
 662		int need_to_validate = 0;
 663
 664		ext_debug("depth %d: num %d, max %d\n",
 665			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 666
 667		ext4_ext_binsearch_idx(inode, path + ppos, block);
 668		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 669		path[ppos].p_depth = i;
 670		path[ppos].p_ext = NULL;
 671
 672		bh = sb_getblk(inode->i_sb, path[ppos].p_block);
 673		if (unlikely(!bh))
 
 674			goto err;
 675		if (!bh_uptodate_or_lock(bh)) {
 676			trace_ext4_ext_load_extent(inode, block,
 677						path[ppos].p_block);
 678			if (bh_submit_read(bh) < 0) {
 679				put_bh(bh);
 680				goto err;
 681			}
 682			/* validate the extent entries */
 683			need_to_validate = 1;
 684		}
 
 685		eh = ext_block_hdr(bh);
 686		ppos++;
 687		if (unlikely(ppos > depth)) {
 688			put_bh(bh);
 689			EXT4_ERROR_INODE(inode,
 690					 "ppos %d > depth %d", ppos, depth);
 691			goto err;
 692		}
 693		path[ppos].p_bh = bh;
 694		path[ppos].p_hdr = eh;
 695		i--;
 696
 697		if (need_to_validate && ext4_ext_check(inode, eh, i))
 698			goto err;
 699	}
 700
 701	path[ppos].p_depth = i;
 702	path[ppos].p_ext = NULL;
 703	path[ppos].p_idx = NULL;
 704
 705	/* find extent */
 706	ext4_ext_binsearch(inode, path + ppos, block);
 707	/* if not an empty leaf */
 708	if (path[ppos].p_ext)
 709		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 710
 711	ext4_ext_show_path(inode, path);
 712
 713	return path;
 714
 715err:
 716	ext4_ext_drop_refs(path);
 717	if (alloc)
 718		kfree(path);
 719	return ERR_PTR(-EIO);
 720}
 721
 722/*
 723 * ext4_ext_insert_index:
 724 * insert new index [@logical;@ptr] into the block at @curp;
 725 * check where to insert: before @curp or after @curp
 726 */
 727static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 728				 struct ext4_ext_path *curp,
 729				 int logical, ext4_fsblk_t ptr)
 730{
 731	struct ext4_extent_idx *ix;
 732	int len, err;
 733
 734	err = ext4_ext_get_access(handle, inode, curp);
 735	if (err)
 736		return err;
 737
 738	if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 739		EXT4_ERROR_INODE(inode,
 740				 "logical %d == ei_block %d!",
 741				 logical, le32_to_cpu(curp->p_idx->ei_block));
 742		return -EIO;
 743	}
 744
 745	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 746			     >= le16_to_cpu(curp->p_hdr->eh_max))) {
 747		EXT4_ERROR_INODE(inode,
 748				 "eh_entries %d >= eh_max %d!",
 749				 le16_to_cpu(curp->p_hdr->eh_entries),
 750				 le16_to_cpu(curp->p_hdr->eh_max));
 751		return -EIO;
 752	}
 753
 754	len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
 755	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 756		/* insert after */
 757		if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
 758			len = (len - 1) * sizeof(struct ext4_extent_idx);
 759			len = len < 0 ? 0 : len;
 760			ext_debug("insert new index %d after: %llu. "
 761					"move %d from 0x%p to 0x%p\n",
 762					logical, ptr, len,
 763					(curp->p_idx + 1), (curp->p_idx + 2));
 764			memmove(curp->p_idx + 2, curp->p_idx + 1, len);
 765		}
 766		ix = curp->p_idx + 1;
 767	} else {
 768		/* insert before */
 769		len = len * sizeof(struct ext4_extent_idx);
 770		len = len < 0 ? 0 : len;
 771		ext_debug("insert new index %d before: %llu. "
 772				"move %d from 0x%p to 0x%p\n",
 773				logical, ptr, len,
 774				curp->p_idx, (curp->p_idx + 1));
 775		memmove(curp->p_idx + 1, curp->p_idx, len);
 776		ix = curp->p_idx;
 777	}
 778
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 779	ix->ei_block = cpu_to_le32(logical);
 780	ext4_idx_store_pblock(ix, ptr);
 781	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 782
 783	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 784		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 785		return -EIO;
 786	}
 787
 788	err = ext4_ext_dirty(handle, inode, curp);
 789	ext4_std_error(inode->i_sb, err);
 790
 791	return err;
 792}
 793
 794/*
 795 * ext4_ext_split:
 796 * inserts new subtree into the path, using free index entry
 797 * at depth @at:
 798 * - allocates all needed blocks (new leaf and all intermediate index blocks)
 799 * - makes decision where to split
 800 * - moves remaining extents and index entries (right to the split point)
 801 *   into the newly allocated blocks
 802 * - initializes subtree
 803 */
 804static int ext4_ext_split(handle_t *handle, struct inode *inode,
 805			  unsigned int flags,
 806			  struct ext4_ext_path *path,
 807			  struct ext4_extent *newext, int at)
 808{
 809	struct buffer_head *bh = NULL;
 810	int depth = ext_depth(inode);
 811	struct ext4_extent_header *neh;
 812	struct ext4_extent_idx *fidx;
 813	int i = at, k, m, a;
 814	ext4_fsblk_t newblock, oldblock;
 815	__le32 border;
 816	ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
 
 817	int err = 0;
 
 
 
 
 818
 819	/* make decision: where to split? */
 820	/* FIXME: now decision is simplest: at current extent */
 821
 822	/* if current leaf will be split, then we should use
 823	 * border from split point */
 824	if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
 825		EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
 826		return -EIO;
 827	}
 828	if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
 829		border = path[depth].p_ext[1].ee_block;
 830		ext_debug("leaf will be split."
 831				" next leaf starts at %d\n",
 832				  le32_to_cpu(border));
 833	} else {
 834		border = newext->ee_block;
 835		ext_debug("leaf will be added."
 836				" next leaf starts at %d\n",
 837				le32_to_cpu(border));
 838	}
 839
 840	/*
 841	 * If error occurs, then we break processing
 842	 * and mark filesystem read-only. index won't
 843	 * be inserted and tree will be in consistent
 844	 * state. Next mount will repair buffers too.
 845	 */
 846
 847	/*
 848	 * Get array to track all allocated blocks.
 849	 * We need this to handle errors and free blocks
 850	 * upon them.
 851	 */
 852	ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
 853	if (!ablocks)
 854		return -ENOMEM;
 855
 856	/* allocate all needed blocks */
 857	ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
 858	for (a = 0; a < depth - at; a++) {
 859		newblock = ext4_ext_new_meta_block(handle, inode, path,
 860						   newext, &err, flags);
 861		if (newblock == 0)
 862			goto cleanup;
 863		ablocks[a] = newblock;
 864	}
 865
 866	/* initialize new leaf */
 867	newblock = ablocks[--a];
 868	if (unlikely(newblock == 0)) {
 869		EXT4_ERROR_INODE(inode, "newblock == 0!");
 870		err = -EIO;
 871		goto cleanup;
 872	}
 873	bh = sb_getblk(inode->i_sb, newblock);
 874	if (!bh) {
 875		err = -EIO;
 876		goto cleanup;
 877	}
 878	lock_buffer(bh);
 879
 880	err = ext4_journal_get_create_access(handle, bh);
 
 881	if (err)
 882		goto cleanup;
 883
 884	neh = ext_block_hdr(bh);
 885	neh->eh_entries = 0;
 886	neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
 887	neh->eh_magic = EXT4_EXT_MAGIC;
 888	neh->eh_depth = 0;
 
 889
 890	/* move remainder of path[depth] to the new leaf */
 891	if (unlikely(path[depth].p_hdr->eh_entries !=
 892		     path[depth].p_hdr->eh_max)) {
 893		EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
 894				 path[depth].p_hdr->eh_entries,
 895				 path[depth].p_hdr->eh_max);
 896		err = -EIO;
 897		goto cleanup;
 898	}
 899	/* start copy from next extent */
 900	m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
 901	ext4_ext_show_move(inode, path, newblock, depth);
 902	if (m) {
 903		struct ext4_extent *ex;
 904		ex = EXT_FIRST_EXTENT(neh);
 905		memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
 906		le16_add_cpu(&neh->eh_entries, m);
 907	}
 908
 
 
 
 
 
 909	set_buffer_uptodate(bh);
 910	unlock_buffer(bh);
 911
 912	err = ext4_handle_dirty_metadata(handle, inode, bh);
 913	if (err)
 914		goto cleanup;
 915	brelse(bh);
 916	bh = NULL;
 917
 918	/* correct old leaf */
 919	if (m) {
 920		err = ext4_ext_get_access(handle, inode, path + depth);
 921		if (err)
 922			goto cleanup;
 923		le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
 924		err = ext4_ext_dirty(handle, inode, path + depth);
 925		if (err)
 926			goto cleanup;
 927
 928	}
 929
 930	/* create intermediate indexes */
 931	k = depth - at - 1;
 932	if (unlikely(k < 0)) {
 933		EXT4_ERROR_INODE(inode, "k %d < 0!", k);
 934		err = -EIO;
 935		goto cleanup;
 936	}
 937	if (k)
 938		ext_debug("create %d intermediate indices\n", k);
 939	/* insert new index into current index block */
 940	/* current depth stored in i var */
 941	i = depth - 1;
 942	while (k--) {
 943		oldblock = newblock;
 944		newblock = ablocks[--a];
 945		bh = sb_getblk(inode->i_sb, newblock);
 946		if (!bh) {
 947			err = -EIO;
 948			goto cleanup;
 949		}
 950		lock_buffer(bh);
 951
 952		err = ext4_journal_get_create_access(handle, bh);
 
 953		if (err)
 954			goto cleanup;
 955
 956		neh = ext_block_hdr(bh);
 957		neh->eh_entries = cpu_to_le16(1);
 958		neh->eh_magic = EXT4_EXT_MAGIC;
 959		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
 960		neh->eh_depth = cpu_to_le16(depth - i);
 
 961		fidx = EXT_FIRST_INDEX(neh);
 962		fidx->ei_block = border;
 963		ext4_idx_store_pblock(fidx, oldblock);
 964
 965		ext_debug("int.index at %d (block %llu): %u -> %llu\n",
 966				i, newblock, le32_to_cpu(border), oldblock);
 967
 968		/* move remainder of path[i] to the new index block */
 969		if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
 970					EXT_LAST_INDEX(path[i].p_hdr))) {
 971			EXT4_ERROR_INODE(inode,
 972					 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
 973					 le32_to_cpu(path[i].p_ext->ee_block));
 974			err = -EIO;
 975			goto cleanup;
 976		}
 977		/* start copy indexes */
 978		m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
 979		ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
 980				EXT_MAX_INDEX(path[i].p_hdr));
 981		ext4_ext_show_move(inode, path, newblock, i);
 982		if (m) {
 983			memmove(++fidx, path[i].p_idx,
 984				sizeof(struct ext4_extent_idx) * m);
 985			le16_add_cpu(&neh->eh_entries, m);
 986		}
 
 
 
 
 
 
 987		set_buffer_uptodate(bh);
 988		unlock_buffer(bh);
 989
 990		err = ext4_handle_dirty_metadata(handle, inode, bh);
 991		if (err)
 992			goto cleanup;
 993		brelse(bh);
 994		bh = NULL;
 995
 996		/* correct old index */
 997		if (m) {
 998			err = ext4_ext_get_access(handle, inode, path + i);
 999			if (err)
1000				goto cleanup;
1001			le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1002			err = ext4_ext_dirty(handle, inode, path + i);
1003			if (err)
1004				goto cleanup;
1005		}
1006
1007		i--;
1008	}
1009
1010	/* insert new index */
1011	err = ext4_ext_insert_index(handle, inode, path + at,
1012				    le32_to_cpu(border), newblock);
1013
1014cleanup:
1015	if (bh) {
1016		if (buffer_locked(bh))
1017			unlock_buffer(bh);
1018		brelse(bh);
1019	}
1020
1021	if (err) {
1022		/* free all allocated blocks in error case */
1023		for (i = 0; i < depth; i++) {
1024			if (!ablocks[i])
1025				continue;
1026			ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1027					 EXT4_FREE_BLOCKS_METADATA);
1028		}
1029	}
1030	kfree(ablocks);
1031
1032	return err;
1033}
1034
1035/*
1036 * ext4_ext_grow_indepth:
1037 * implements tree growing procedure:
1038 * - allocates new block
1039 * - moves top-level data (index block or leaf) into the new block
1040 * - initializes new top-level, creating index that points to the
1041 *   just created block
1042 */
1043static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1044				 unsigned int flags,
1045				 struct ext4_ext_path *path,
1046				 struct ext4_extent *newext)
1047{
1048	struct ext4_ext_path *curp = path;
1049	struct ext4_extent_header *neh;
1050	struct buffer_head *bh;
1051	ext4_fsblk_t newblock;
 
1052	int err = 0;
 
1053
1054	newblock = ext4_ext_new_meta_block(handle, inode, path,
1055		newext, &err, flags);
 
 
 
 
 
 
 
 
1056	if (newblock == 0)
1057		return err;
1058
1059	bh = sb_getblk(inode->i_sb, newblock);
1060	if (!bh) {
1061		err = -EIO;
1062		ext4_std_error(inode->i_sb, err);
1063		return err;
1064	}
1065	lock_buffer(bh);
1066
1067	err = ext4_journal_get_create_access(handle, bh);
 
1068	if (err) {
1069		unlock_buffer(bh);
1070		goto out;
1071	}
1072
 
1073	/* move top-level index/leaf into new block */
1074	memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
 
 
1075
1076	/* set size of new block */
1077	neh = ext_block_hdr(bh);
1078	/* old root could have indexes or leaves
1079	 * so calculate e_max right way */
1080	if (ext_depth(inode))
1081		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1082	else
1083		neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1084	neh->eh_magic = EXT4_EXT_MAGIC;
 
1085	set_buffer_uptodate(bh);
 
1086	unlock_buffer(bh);
1087
1088	err = ext4_handle_dirty_metadata(handle, inode, bh);
1089	if (err)
1090		goto out;
1091
1092	/* create index in new top-level index: num,max,pointer */
1093	err = ext4_ext_get_access(handle, inode, curp);
1094	if (err)
1095		goto out;
1096
1097	curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
1098	curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1099	curp->p_hdr->eh_entries = cpu_to_le16(1);
1100	curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
1101
1102	if (path[0].p_hdr->eh_depth)
1103		curp->p_idx->ei_block =
1104			EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
1105	else
1106		curp->p_idx->ei_block =
1107			EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
1108	ext4_idx_store_pblock(curp->p_idx, newblock);
1109
1110	neh = ext_inode_hdr(inode);
1111	ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
 
 
 
 
 
 
 
 
1112		  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1113		  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1114		  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1115
1116	neh->eh_depth = cpu_to_le16(path->p_depth + 1);
1117	err = ext4_ext_dirty(handle, inode, curp);
1118out:
1119	brelse(bh);
1120
1121	return err;
1122}
1123
1124/*
1125 * ext4_ext_create_new_leaf:
1126 * finds empty index and adds new leaf.
1127 * if no free index is found, then it requests in-depth growing.
1128 */
1129static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1130				    unsigned int flags,
1131				    struct ext4_ext_path *path,
1132				    struct ext4_extent *newext)
 
1133{
1134	struct ext4_ext_path *curp;
1135	int depth, i, err = 0;
 
1136
1137repeat:
1138	i = depth = ext_depth(inode);
1139
1140	/* walk up to the tree and look for free index entry */
1141	curp = path + depth;
1142	while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1143		i--;
1144		curp--;
1145	}
1146
1147	/* we use already allocated block for index block,
1148	 * so subsequent data blocks should be contiguous */
1149	if (EXT_HAS_FREE_INDEX(curp)) {
1150		/* if we found index with free entry, then use that
1151		 * entry: create all needed subtree and add new leaf */
1152		err = ext4_ext_split(handle, inode, flags, path, newext, i);
1153		if (err)
1154			goto out;
1155
1156		/* refill path */
1157		ext4_ext_drop_refs(path);
1158		path = ext4_ext_find_extent(inode,
1159				    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1160				    path);
1161		if (IS_ERR(path))
1162			err = PTR_ERR(path);
1163	} else {
1164		/* tree is full, time to grow in depth */
1165		err = ext4_ext_grow_indepth(handle, inode, flags,
1166					    path, newext);
1167		if (err)
1168			goto out;
1169
1170		/* refill path */
1171		ext4_ext_drop_refs(path);
1172		path = ext4_ext_find_extent(inode,
1173				   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1174				    path);
1175		if (IS_ERR(path)) {
1176			err = PTR_ERR(path);
1177			goto out;
1178		}
1179
1180		/*
1181		 * only first (depth 0 -> 1) produces free space;
1182		 * in all other cases we have to split the grown tree
1183		 */
1184		depth = ext_depth(inode);
1185		if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1186			/* now we need to split */
1187			goto repeat;
1188		}
 
 
 
 
1189	}
1190
1191out:
1192	return err;
 
 
 
1193}
1194
1195/*
1196 * search the closest allocated block to the left for *logical
1197 * and returns it at @logical + it's physical address at @phys
1198 * if *logical is the smallest allocated block, the function
1199 * returns 0 at @phys
1200 * return value contains 0 (success) or error code
1201 */
1202static int ext4_ext_search_left(struct inode *inode,
1203				struct ext4_ext_path *path,
1204				ext4_lblk_t *logical, ext4_fsblk_t *phys)
1205{
1206	struct ext4_extent_idx *ix;
1207	struct ext4_extent *ex;
1208	int depth, ee_len;
1209
1210	if (unlikely(path == NULL)) {
1211		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1212		return -EIO;
1213	}
1214	depth = path->p_depth;
1215	*phys = 0;
1216
1217	if (depth == 0 && path->p_ext == NULL)
1218		return 0;
1219
1220	/* usually extent in the path covers blocks smaller
1221	 * then *logical, but it can be that extent is the
1222	 * first one in the file */
1223
1224	ex = path[depth].p_ext;
1225	ee_len = ext4_ext_get_actual_len(ex);
1226	if (*logical < le32_to_cpu(ex->ee_block)) {
1227		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1228			EXT4_ERROR_INODE(inode,
1229					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1230					 *logical, le32_to_cpu(ex->ee_block));
1231			return -EIO;
1232		}
1233		while (--depth >= 0) {
1234			ix = path[depth].p_idx;
1235			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1236				EXT4_ERROR_INODE(inode,
1237				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1238				  ix != NULL ? ix->ei_block : 0,
1239				  EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1240				    EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0,
1241				  depth);
1242				return -EIO;
1243			}
1244		}
1245		return 0;
1246	}
1247
1248	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1249		EXT4_ERROR_INODE(inode,
1250				 "logical %d < ee_block %d + ee_len %d!",
1251				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1252		return -EIO;
1253	}
1254
1255	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1256	*phys = ext4_ext_pblock(ex) + ee_len - 1;
1257	return 0;
1258}
1259
1260/*
1261 * search the closest allocated block to the right for *logical
1262 * and returns it at @logical + it's physical address at @phys
1263 * if *logical is the smallest allocated block, the function
1264 * returns 0 at @phys
1265 * return value contains 0 (success) or error code
1266 */
1267static int ext4_ext_search_right(struct inode *inode,
1268				 struct ext4_ext_path *path,
1269				 ext4_lblk_t *logical, ext4_fsblk_t *phys)
 
1270{
1271	struct buffer_head *bh = NULL;
1272	struct ext4_extent_header *eh;
1273	struct ext4_extent_idx *ix;
1274	struct ext4_extent *ex;
1275	ext4_fsblk_t block;
1276	int depth;	/* Note, NOT eh_depth; depth from top of tree */
1277	int ee_len;
1278
1279	if (unlikely(path == NULL)) {
1280		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1281		return -EIO;
1282	}
1283	depth = path->p_depth;
1284	*phys = 0;
1285
1286	if (depth == 0 && path->p_ext == NULL)
1287		return 0;
1288
1289	/* usually extent in the path covers blocks smaller
1290	 * then *logical, but it can be that extent is the
1291	 * first one in the file */
1292
1293	ex = path[depth].p_ext;
1294	ee_len = ext4_ext_get_actual_len(ex);
1295	if (*logical < le32_to_cpu(ex->ee_block)) {
1296		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1297			EXT4_ERROR_INODE(inode,
1298					 "first_extent(path[%d].p_hdr) != ex",
1299					 depth);
1300			return -EIO;
1301		}
1302		while (--depth >= 0) {
1303			ix = path[depth].p_idx;
1304			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1305				EXT4_ERROR_INODE(inode,
1306						 "ix != EXT_FIRST_INDEX *logical %d!",
1307						 *logical);
1308				return -EIO;
1309			}
1310		}
1311		*logical = le32_to_cpu(ex->ee_block);
1312		*phys = ext4_ext_pblock(ex);
1313		return 0;
1314	}
1315
1316	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1317		EXT4_ERROR_INODE(inode,
1318				 "logical %d < ee_block %d + ee_len %d!",
1319				 *logical, le32_to_cpu(ex->ee_block), ee_len);
1320		return -EIO;
1321	}
1322
1323	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1324		/* next allocated block in this leaf */
1325		ex++;
1326		*logical = le32_to_cpu(ex->ee_block);
1327		*phys = ext4_ext_pblock(ex);
1328		return 0;
1329	}
1330
1331	/* go up and search for index to the right */
1332	while (--depth >= 0) {
1333		ix = path[depth].p_idx;
1334		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1335			goto got_index;
1336	}
1337
1338	/* we've gone up to the root and found no index to the right */
1339	return 0;
1340
1341got_index:
1342	/* we've found index to the right, let's
1343	 * follow it and find the closest allocated
1344	 * block to the right */
1345	ix++;
1346	block = ext4_idx_pblock(ix);
1347	while (++depth < path->p_depth) {
1348		bh = sb_bread(inode->i_sb, block);
1349		if (bh == NULL)
1350			return -EIO;
1351		eh = ext_block_hdr(bh);
1352		/* subtract from p_depth to get proper eh_depth */
1353		if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1354			put_bh(bh);
1355			return -EIO;
1356		}
1357		ix = EXT_FIRST_INDEX(eh);
1358		block = ext4_idx_pblock(ix);
1359		put_bh(bh);
1360	}
1361
1362	bh = sb_bread(inode->i_sb, block);
1363	if (bh == NULL)
1364		return -EIO;
1365	eh = ext_block_hdr(bh);
1366	if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1367		put_bh(bh);
1368		return -EIO;
1369	}
1370	ex = EXT_FIRST_EXTENT(eh);
 
1371	*logical = le32_to_cpu(ex->ee_block);
1372	*phys = ext4_ext_pblock(ex);
1373	put_bh(bh);
1374	return 0;
 
 
 
1375}
1376
1377/*
1378 * ext4_ext_next_allocated_block:
1379 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1380 * NOTE: it considers block number from index entry as
1381 * allocated block. Thus, index entries have to be consistent
1382 * with leaves.
1383 */
1384static ext4_lblk_t
1385ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1386{
1387	int depth;
1388
1389	BUG_ON(path == NULL);
1390	depth = path->p_depth;
1391
1392	if (depth == 0 && path->p_ext == NULL)
1393		return EXT_MAX_BLOCKS;
1394
1395	while (depth >= 0) {
 
 
1396		if (depth == path->p_depth) {
1397			/* leaf */
1398			if (path[depth].p_ext !=
1399					EXT_LAST_EXTENT(path[depth].p_hdr))
1400			  return le32_to_cpu(path[depth].p_ext[1].ee_block);
1401		} else {
1402			/* index */
1403			if (path[depth].p_idx !=
1404					EXT_LAST_INDEX(path[depth].p_hdr))
1405			  return le32_to_cpu(path[depth].p_idx[1].ei_block);
1406		}
1407		depth--;
1408	}
1409
1410	return EXT_MAX_BLOCKS;
1411}
1412
1413/*
1414 * ext4_ext_next_leaf_block:
1415 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1416 */
1417static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1418{
1419	int depth;
1420
1421	BUG_ON(path == NULL);
1422	depth = path->p_depth;
1423
1424	/* zero-tree has no leaf blocks at all */
1425	if (depth == 0)
1426		return EXT_MAX_BLOCKS;
1427
1428	/* go to index block */
1429	depth--;
1430
1431	while (depth >= 0) {
1432		if (path[depth].p_idx !=
1433				EXT_LAST_INDEX(path[depth].p_hdr))
1434			return (ext4_lblk_t)
1435				le32_to_cpu(path[depth].p_idx[1].ei_block);
1436		depth--;
1437	}
1438
1439	return EXT_MAX_BLOCKS;
1440}
1441
1442/*
1443 * ext4_ext_correct_indexes:
1444 * if leaf gets modified and modified extent is first in the leaf,
1445 * then we have to correct all indexes above.
1446 * TODO: do we need to correct tree in all cases?
1447 */
1448static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1449				struct ext4_ext_path *path)
1450{
1451	struct ext4_extent_header *eh;
1452	int depth = ext_depth(inode);
1453	struct ext4_extent *ex;
1454	__le32 border;
1455	int k, err = 0;
1456
1457	eh = path[depth].p_hdr;
1458	ex = path[depth].p_ext;
1459
1460	if (unlikely(ex == NULL || eh == NULL)) {
1461		EXT4_ERROR_INODE(inode,
1462				 "ex %p == NULL or eh %p == NULL", ex, eh);
1463		return -EIO;
1464	}
1465
1466	if (depth == 0) {
1467		/* there is no tree at all */
1468		return 0;
1469	}
1470
1471	if (ex != EXT_FIRST_EXTENT(eh)) {
1472		/* we correct tree if first leaf got modified only */
1473		return 0;
1474	}
1475
1476	/*
1477	 * TODO: we need correction if border is smaller than current one
1478	 */
1479	k = depth - 1;
1480	border = path[depth].p_ext->ee_block;
1481	err = ext4_ext_get_access(handle, inode, path + k);
1482	if (err)
1483		return err;
1484	path[k].p_idx->ei_block = border;
1485	err = ext4_ext_dirty(handle, inode, path + k);
1486	if (err)
1487		return err;
1488
1489	while (k--) {
1490		/* change all left-side indexes */
1491		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1492			break;
1493		err = ext4_ext_get_access(handle, inode, path + k);
1494		if (err)
1495			break;
1496		path[k].p_idx->ei_block = border;
1497		err = ext4_ext_dirty(handle, inode, path + k);
1498		if (err)
1499			break;
1500	}
 
 
 
 
 
 
 
 
 
 
 
1501
1502	return err;
1503}
1504
1505int
1506ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1507				struct ext4_extent *ex2)
1508{
1509	unsigned short ext1_ee_len, ext2_ee_len, max_len;
1510
1511	/*
1512	 * Make sure that either both extents are uninitialized, or
1513	 * both are _not_.
1514	 */
1515	if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1516		return 0;
1517
1518	if (ext4_ext_is_uninitialized(ex1))
1519		max_len = EXT_UNINIT_MAX_LEN;
1520	else
1521		max_len = EXT_INIT_MAX_LEN;
1522
1523	ext1_ee_len = ext4_ext_get_actual_len(ex1);
1524	ext2_ee_len = ext4_ext_get_actual_len(ex2);
1525
1526	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1527			le32_to_cpu(ex2->ee_block))
1528		return 0;
1529
1530	/*
1531	 * To allow future support for preallocated extents to be added
1532	 * as an RO_COMPAT feature, refuse to merge to extents if
1533	 * this can result in the top bit of ee_len being set.
1534	 */
1535	if (ext1_ee_len + ext2_ee_len > max_len)
1536		return 0;
1537#ifdef AGGRESSIVE_TEST
1538	if (ext1_ee_len >= 4)
1539		return 0;
1540#endif
1541
1542	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1543		return 1;
1544	return 0;
1545}
1546
1547/*
1548 * This function tries to merge the "ex" extent to the next extent in the tree.
1549 * It always tries to merge towards right. If you want to merge towards
1550 * left, pass "ex - 1" as argument instead of "ex".
1551 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1552 * 1 if they got merged.
1553 */
1554static int ext4_ext_try_to_merge_right(struct inode *inode,
1555				 struct ext4_ext_path *path,
1556				 struct ext4_extent *ex)
1557{
1558	struct ext4_extent_header *eh;
1559	unsigned int depth, len;
1560	int merge_done = 0;
1561	int uninitialized = 0;
1562
1563	depth = ext_depth(inode);
1564	BUG_ON(path[depth].p_hdr == NULL);
1565	eh = path[depth].p_hdr;
1566
1567	while (ex < EXT_LAST_EXTENT(eh)) {
1568		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1569			break;
1570		/* merge with next extent! */
1571		if (ext4_ext_is_uninitialized(ex))
1572			uninitialized = 1;
1573		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1574				+ ext4_ext_get_actual_len(ex + 1));
1575		if (uninitialized)
1576			ext4_ext_mark_uninitialized(ex);
1577
1578		if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1579			len = (EXT_LAST_EXTENT(eh) - ex - 1)
1580				* sizeof(struct ext4_extent);
1581			memmove(ex + 1, ex + 2, len);
1582		}
1583		le16_add_cpu(&eh->eh_entries, -1);
1584		merge_done = 1;
1585		WARN_ON(eh->eh_entries == 0);
1586		if (!eh->eh_entries)
1587			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1588	}
1589
1590	return merge_done;
1591}
1592
1593/*
1594 * This function tries to merge the @ex extent to neighbours in the tree.
1595 * return 1 if merge left else 0.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1596 */
1597static int ext4_ext_try_to_merge(struct inode *inode,
 
1598				  struct ext4_ext_path *path,
1599				  struct ext4_extent *ex) {
 
1600	struct ext4_extent_header *eh;
1601	unsigned int depth;
1602	int merge_done = 0;
1603	int ret = 0;
1604
1605	depth = ext_depth(inode);
1606	BUG_ON(path[depth].p_hdr == NULL);
1607	eh = path[depth].p_hdr;
1608
1609	if (ex > EXT_FIRST_EXTENT(eh))
1610		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1611
1612	if (!merge_done)
1613		ret = ext4_ext_try_to_merge_right(inode, path, ex);
1614
1615	return ret;
1616}
1617
1618/*
1619 * check if a portion of the "newext" extent overlaps with an
1620 * existing extent.
1621 *
1622 * If there is an overlap discovered, it updates the length of the newext
1623 * such that there will be no overlap, and then returns 1.
1624 * If there is no overlap found, it returns 0.
1625 */
1626static unsigned int ext4_ext_check_overlap(struct inode *inode,
 
1627					   struct ext4_extent *newext,
1628					   struct ext4_ext_path *path)
1629{
1630	ext4_lblk_t b1, b2;
1631	unsigned int depth, len1;
1632	unsigned int ret = 0;
1633
1634	b1 = le32_to_cpu(newext->ee_block);
1635	len1 = ext4_ext_get_actual_len(newext);
1636	depth = ext_depth(inode);
1637	if (!path[depth].p_ext)
1638		goto out;
1639	b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1640
1641	/*
1642	 * get the next allocated block if the extent in the path
1643	 * is before the requested block(s)
1644	 */
1645	if (b2 < b1) {
1646		b2 = ext4_ext_next_allocated_block(path);
1647		if (b2 == EXT_MAX_BLOCKS)
1648			goto out;
 
1649	}
1650
1651	/* check for wrap through zero on extent logical start block*/
1652	if (b1 + len1 < b1) {
1653		len1 = EXT_MAX_BLOCKS - b1;
1654		newext->ee_len = cpu_to_le16(len1);
1655		ret = 1;
1656	}
1657
1658	/* check for overlap */
1659	if (b1 + len1 > b2) {
1660		newext->ee_len = cpu_to_le16(b2 - b1);
1661		ret = 1;
1662	}
1663out:
1664	return ret;
1665}
1666
1667/*
1668 * ext4_ext_insert_extent:
1669 * tries to merge requsted extent into the existing extent or
1670 * inserts requested extent as new one into the tree,
1671 * creating new leaf in the no-space case.
1672 */
1673int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1674				struct ext4_ext_path *path,
1675				struct ext4_extent *newext, int flag)
 
1676{
1677	struct ext4_extent_header *eh;
1678	struct ext4_extent *ex, *fex;
1679	struct ext4_extent *nearex; /* nearest extent */
1680	struct ext4_ext_path *npath = NULL;
1681	int depth, len, err;
1682	ext4_lblk_t next;
1683	unsigned uninitialized = 0;
1684	int flags = 0;
1685
 
 
1686	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1687		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1688		return -EIO;
 
1689	}
1690	depth = ext_depth(inode);
1691	ex = path[depth].p_ext;
 
1692	if (unlikely(path[depth].p_hdr == NULL)) {
1693		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1694		return -EIO;
 
1695	}
1696
1697	/* try to insert block into found extent and return */
1698	if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
1699		&& ext4_can_extents_be_merged(inode, ex, newext)) {
1700		ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
1701			  ext4_ext_is_uninitialized(newext),
1702			  ext4_ext_get_actual_len(newext),
1703			  le32_to_cpu(ex->ee_block),
1704			  ext4_ext_is_uninitialized(ex),
1705			  ext4_ext_get_actual_len(ex),
1706			  ext4_ext_pblock(ex));
1707		err = ext4_ext_get_access(handle, inode, path + depth);
1708		if (err)
1709			return err;
1710
1711		/*
1712		 * ext4_can_extents_be_merged should have checked that either
1713		 * both extents are uninitialized, or both aren't. Thus we
1714		 * need to check only one of them here.
 
 
1715		 */
1716		if (ext4_ext_is_uninitialized(ex))
1717			uninitialized = 1;
1718		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1719					+ ext4_ext_get_actual_len(newext));
1720		if (uninitialized)
1721			ext4_ext_mark_uninitialized(ex);
1722		eh = path[depth].p_hdr;
1723		nearex = ex;
1724		goto merge;
1725	}
1726
1727	depth = ext_depth(inode);
1728	eh = path[depth].p_hdr;
1729	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1730		goto has_space;
1731
1732	/* probably next leaf has space for us? */
1733	fex = EXT_LAST_EXTENT(eh);
1734	next = EXT_MAX_BLOCKS;
1735	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1736		next = ext4_ext_next_leaf_block(path);
1737	if (next != EXT_MAX_BLOCKS) {
1738		ext_debug("next leaf block - %d\n", next);
1739		BUG_ON(npath != NULL);
1740		npath = ext4_ext_find_extent(inode, next, NULL);
1741		if (IS_ERR(npath))
1742			return PTR_ERR(npath);
 
 
 
1743		BUG_ON(npath->p_depth != path->p_depth);
1744		eh = npath[depth].p_hdr;
1745		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1746			ext_debug("next leaf isn't full(%d)\n",
1747				  le16_to_cpu(eh->eh_entries));
 
1748			path = npath;
1749			goto has_space;
1750		}
1751		ext_debug("next leaf has no free space(%d,%d)\n",
1752			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 
1753	}
1754
1755	/*
1756	 * There is no free space in the found leaf.
1757	 * We're gonna add a new leaf in the tree.
1758	 */
1759	if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
1760		flags = EXT4_MB_USE_ROOT_BLOCKS;
1761	err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
1762	if (err)
1763		goto cleanup;
 
1764	depth = ext_depth(inode);
1765	eh = path[depth].p_hdr;
1766
1767has_space:
1768	nearex = path[depth].p_ext;
1769
1770	err = ext4_ext_get_access(handle, inode, path + depth);
1771	if (err)
1772		goto cleanup;
1773
1774	if (!nearex) {
1775		/* there is no extent in this leaf, create first one */
1776		ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n",
1777				le32_to_cpu(newext->ee_block),
1778				ext4_ext_pblock(newext),
1779				ext4_ext_is_uninitialized(newext),
1780				ext4_ext_get_actual_len(newext));
1781		path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1782	} else if (le32_to_cpu(newext->ee_block)
 
1783			   > le32_to_cpu(nearex->ee_block)) {
1784/*		BUG_ON(newext->ee_block == nearex->ee_block); */
1785		if (nearex != EXT_LAST_EXTENT(eh)) {
1786			len = EXT_MAX_EXTENT(eh) - nearex;
1787			len = (len - 1) * sizeof(struct ext4_extent);
1788			len = len < 0 ? 0 : len;
1789			ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, "
1790					"move %d from 0x%p to 0x%p\n",
1791					le32_to_cpu(newext->ee_block),
1792					ext4_ext_pblock(newext),
1793					ext4_ext_is_uninitialized(newext),
1794					ext4_ext_get_actual_len(newext),
1795					nearex, len, nearex + 1, nearex + 2);
1796			memmove(nearex + 2, nearex + 1, len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1797		}
1798		path[depth].p_ext = nearex + 1;
1799	} else {
1800		BUG_ON(newext->ee_block == nearex->ee_block);
1801		len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1802		len = len < 0 ? 0 : len;
1803		ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, "
1804				"move %d from 0x%p to 0x%p\n",
1805				le32_to_cpu(newext->ee_block),
1806				ext4_ext_pblock(newext),
1807				ext4_ext_is_uninitialized(newext),
1808				ext4_ext_get_actual_len(newext),
1809				nearex, len, nearex, nearex + 1);
1810		memmove(nearex + 1, nearex, len);
1811		path[depth].p_ext = nearex;
1812	}
1813
1814	le16_add_cpu(&eh->eh_entries, 1);
1815	nearex = path[depth].p_ext;
1816	nearex->ee_block = newext->ee_block;
1817	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
1818	nearex->ee_len = newext->ee_len;
1819
1820merge:
1821	/* try to merge extents to the right */
1822	if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
1823		ext4_ext_try_to_merge(inode, path, nearex);
1824
1825	/* try to merge extents to the left */
1826
1827	/* time to correct all indexes above */
1828	err = ext4_ext_correct_indexes(handle, inode, path);
1829	if (err)
1830		goto cleanup;
1831
1832	err = ext4_ext_dirty(handle, inode, path + depth);
 
 
1833
1834cleanup:
1835	if (npath) {
1836		ext4_ext_drop_refs(npath);
1837		kfree(npath);
1838	}
1839	ext4_ext_invalidate_cache(inode);
1840	return err;
1841}
1842
1843static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1844			       ext4_lblk_t num, ext_prepare_callback func,
1845			       void *cbdata)
1846{
1847	struct ext4_ext_path *path = NULL;
1848	struct ext4_ext_cache cbex;
1849	struct ext4_extent *ex;
1850	ext4_lblk_t next, start = 0, end = 0;
1851	ext4_lblk_t last = block + num;
1852	int depth, exists, err = 0;
1853
1854	BUG_ON(func == NULL);
1855	BUG_ON(inode == NULL);
1856
1857	while (block < last && block != EXT_MAX_BLOCKS) {
1858		num = last - block;
1859		/* find extent for this block */
1860		down_read(&EXT4_I(inode)->i_data_sem);
1861		path = ext4_ext_find_extent(inode, block, path);
1862		up_read(&EXT4_I(inode)->i_data_sem);
1863		if (IS_ERR(path)) {
1864			err = PTR_ERR(path);
1865			path = NULL;
1866			break;
1867		}
1868
1869		depth = ext_depth(inode);
1870		if (unlikely(path[depth].p_hdr == NULL)) {
1871			EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1872			err = -EIO;
1873			break;
1874		}
1875		ex = path[depth].p_ext;
1876		next = ext4_ext_next_allocated_block(path);
1877
1878		exists = 0;
1879		if (!ex) {
1880			/* there is no extent yet, so try to allocate
1881			 * all requested space */
1882			start = block;
1883			end = block + num;
1884		} else if (le32_to_cpu(ex->ee_block) > block) {
1885			/* need to allocate space before found extent */
1886			start = block;
1887			end = le32_to_cpu(ex->ee_block);
1888			if (block + num < end)
1889				end = block + num;
1890		} else if (block >= le32_to_cpu(ex->ee_block)
1891					+ ext4_ext_get_actual_len(ex)) {
1892			/* need to allocate space after found extent */
1893			start = block;
1894			end = block + num;
1895			if (end >= next)
1896				end = next;
1897		} else if (block >= le32_to_cpu(ex->ee_block)) {
1898			/*
1899			 * some part of requested space is covered
1900			 * by found extent
1901			 */
1902			start = block;
1903			end = le32_to_cpu(ex->ee_block)
1904				+ ext4_ext_get_actual_len(ex);
1905			if (block + num < end)
1906				end = block + num;
1907			exists = 1;
1908		} else {
1909			BUG();
1910		}
1911		BUG_ON(end <= start);
1912
1913		if (!exists) {
1914			cbex.ec_block = start;
1915			cbex.ec_len = end - start;
1916			cbex.ec_start = 0;
1917		} else {
1918			cbex.ec_block = le32_to_cpu(ex->ee_block);
1919			cbex.ec_len = ext4_ext_get_actual_len(ex);
1920			cbex.ec_start = ext4_ext_pblock(ex);
1921		}
1922
1923		if (unlikely(cbex.ec_len == 0)) {
1924			EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
1925			err = -EIO;
1926			break;
1927		}
1928		err = func(inode, next, &cbex, ex, cbdata);
1929		ext4_ext_drop_refs(path);
1930
1931		if (err < 0)
1932			break;
1933
1934		if (err == EXT_REPEAT)
1935			continue;
1936		else if (err == EXT_BREAK) {
1937			err = 0;
1938			break;
1939		}
1940
1941		if (ext_depth(inode) != depth) {
1942			/* depth was changed. we have to realloc path */
1943			kfree(path);
1944			path = NULL;
1945		}
1946
1947		block = cbex.ec_block + cbex.ec_len;
1948	}
1949
1950	if (path) {
1951		ext4_ext_drop_refs(path);
1952		kfree(path);
1953	}
1954
1955	return err;
1956}
1957
1958static void
1959ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1960			__u32 len, ext4_fsblk_t start)
1961{
1962	struct ext4_ext_cache *cex;
1963	BUG_ON(len == 0);
1964	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1965	cex = &EXT4_I(inode)->i_cached_extent;
1966	cex->ec_block = block;
1967	cex->ec_len = len;
1968	cex->ec_start = start;
1969	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1970}
1971
1972/*
1973 * ext4_ext_put_gap_in_cache:
1974 * calculate boundaries of the gap that the requested block fits into
1975 * and cache this gap
 
 
 
 
 
 
 
 
1976 */
1977static void
1978ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1979				ext4_lblk_t block)
1980{
1981	int depth = ext_depth(inode);
1982	unsigned long len;
1983	ext4_lblk_t lblock;
1984	struct ext4_extent *ex;
 
1985
1986	ex = path[depth].p_ext;
1987	if (ex == NULL) {
1988		/* there is no extent yet, so gap is [0;-] */
1989		lblock = 0;
1990		len = EXT_MAX_BLOCKS;
1991		ext_debug("cache gap(whole file):");
1992	} else if (block < le32_to_cpu(ex->ee_block)) {
1993		lblock = block;
1994		len = le32_to_cpu(ex->ee_block) - block;
1995		ext_debug("cache gap(before): %u [%u:%u]",
1996				block,
1997				le32_to_cpu(ex->ee_block),
1998				 ext4_ext_get_actual_len(ex));
1999	} else if (block >= le32_to_cpu(ex->ee_block)
2000			+ ext4_ext_get_actual_len(ex)) {
2001		ext4_lblk_t next;
2002		lblock = le32_to_cpu(ex->ee_block)
2003			+ ext4_ext_get_actual_len(ex);
2004
 
2005		next = ext4_ext_next_allocated_block(path);
2006		ext_debug("cache gap(after): [%u:%u] %u",
2007				le32_to_cpu(ex->ee_block),
2008				ext4_ext_get_actual_len(ex),
2009				block);
2010		BUG_ON(next == lblock);
2011		len = next - lblock;
2012	} else {
2013		lblock = len = 0;
2014		BUG();
2015	}
2016
2017	ext_debug(" -> %u:%lu\n", lblock, len);
2018	ext4_ext_put_in_cache(inode, lblock, len, 0);
2019}
2020
2021/*
2022 * ext4_ext_check_cache()
2023 * Checks to see if the given block is in the cache.
2024 * If it is, the cached extent is stored in the given
2025 * cache extent pointer.  If the cached extent is a hole,
2026 * this routine should be used instead of
2027 * ext4_ext_in_cache if the calling function needs to
2028 * know the size of the hole.
2029 *
2030 * @inode: The files inode
2031 * @block: The block to look for in the cache
2032 * @ex:    Pointer where the cached extent will be stored
2033 *         if it contains block
2034 *
2035 * Return 0 if cache is invalid; 1 if the cache is valid
2036 */
2037static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block,
2038	struct ext4_ext_cache *ex){
2039	struct ext4_ext_cache *cex;
2040	struct ext4_sb_info *sbi;
2041	int ret = 0;
2042
2043	/*
2044	 * We borrow i_block_reservation_lock to protect i_cached_extent
2045	 */
2046	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
2047	cex = &EXT4_I(inode)->i_cached_extent;
2048	sbi = EXT4_SB(inode->i_sb);
2049
2050	/* has cache valid data? */
2051	if (cex->ec_len == 0)
2052		goto errout;
2053
2054	if (in_range(block, cex->ec_block, cex->ec_len)) {
2055		memcpy(ex, cex, sizeof(struct ext4_ext_cache));
2056		ext_debug("%u cached by %u:%u:%llu\n",
2057				block,
2058				cex->ec_block, cex->ec_len, cex->ec_start);
2059		ret = 1;
2060	}
2061errout:
2062	if (!ret)
2063		sbi->extent_cache_misses++;
2064	else
2065		sbi->extent_cache_hits++;
2066	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
2067	return ret;
2068}
2069
2070/*
2071 * ext4_ext_in_cache()
2072 * Checks to see if the given block is in the cache.
2073 * If it is, the cached extent is stored in the given
2074 * extent pointer.
2075 *
2076 * @inode: The files inode
2077 * @block: The block to look for in the cache
2078 * @ex:    Pointer where the cached extent will be stored
2079 *         if it contains block
2080 *
2081 * Return 0 if cache is invalid; 1 if the cache is valid
2082 */
2083static int
2084ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
2085			struct ext4_extent *ex)
2086{
2087	struct ext4_ext_cache cex;
2088	int ret = 0;
2089
2090	if (ext4_ext_check_cache(inode, block, &cex)) {
2091		ex->ee_block = cpu_to_le32(cex.ec_block);
2092		ext4_ext_store_pblock(ex, cex.ec_start);
2093		ex->ee_len = cpu_to_le16(cex.ec_len);
2094		ret = 1;
2095	}
2096
2097	return ret;
2098}
2099
2100
2101/*
2102 * ext4_ext_rm_idx:
2103 * removes index from the index block.
2104 */
2105static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2106			struct ext4_ext_path *path)
2107{
2108	int err;
2109	ext4_fsblk_t leaf;
 
2110
2111	/* free index block */
2112	path--;
2113	leaf = ext4_idx_pblock(path->p_idx);
2114	if (unlikely(path->p_hdr->eh_entries == 0)) {
2115		EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2116		return -EIO;
2117	}
2118	err = ext4_ext_get_access(handle, inode, path);
2119	if (err)
2120		return err;
2121
2122	if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2123		int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2124		len *= sizeof(struct ext4_extent_idx);
2125		memmove(path->p_idx, path->p_idx + 1, len);
2126	}
2127
2128	le16_add_cpu(&path->p_hdr->eh_entries, -1);
2129	err = ext4_ext_dirty(handle, inode, path);
2130	if (err)
2131		return err;
2132	ext_debug("index is empty, remove it, free block %llu\n", leaf);
 
 
2133	ext4_free_blocks(handle, inode, NULL, leaf, 1,
2134			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2135	return err;
2136}
2137
2138/*
2139 * ext4_ext_calc_credits_for_single_extent:
2140 * This routine returns max. credits that needed to insert an extent
2141 * to the extent tree.
2142 * When pass the actual path, the caller should calculate credits
2143 * under i_data_sem.
2144 */
2145int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2146						struct ext4_ext_path *path)
2147{
2148	if (path) {
2149		int depth = ext_depth(inode);
2150		int ret = 0;
2151
2152		/* probably there is space in leaf? */
2153		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2154				< le16_to_cpu(path[depth].p_hdr->eh_max)) {
2155
2156			/*
2157			 *  There are some space in the leaf tree, no
2158			 *  need to account for leaf block credit
2159			 *
2160			 *  bitmaps and block group descriptor blocks
2161			 *  and other metadat blocks still need to be
2162			 *  accounted.
2163			 */
2164			/* 1 bitmap, 1 block group descriptor */
2165			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2166			return ret;
2167		}
2168	}
2169
2170	return ext4_chunk_trans_blocks(inode, nrblocks);
2171}
2172
2173/*
2174 * How many index/leaf blocks need to change/allocate to modify nrblocks?
2175 *
2176 * if nrblocks are fit in a single extent (chunk flag is 1), then
2177 * in the worse case, each tree level index/leaf need to be changed
2178 * if the tree split due to insert a new extent, then the old tree
2179 * index/leaf need to be updated too
2180 *
2181 * If the nrblocks are discontiguous, they could cause
2182 * the whole tree split more than once, but this is really rare.
2183 */
2184int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2185{
2186	int index;
2187	int depth = ext_depth(inode);
 
 
 
 
2188
2189	if (chunk)
 
 
2190		index = depth * 2;
2191	else
2192		index = depth * 3;
2193
2194	return index;
2195}
2196
2197static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2198				struct ext4_extent *ex,
2199				ext4_lblk_t from, ext4_lblk_t to)
2200{
2201	unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2202	int flags = EXT4_FREE_BLOCKS_FORGET;
 
 
 
 
 
2203
2204	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2205		flags |= EXT4_FREE_BLOCKS_METADATA;
2206#ifdef EXTENTS_STATS
2207	{
2208		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2209		spin_lock(&sbi->s_ext_stats_lock);
2210		sbi->s_ext_blocks += ee_len;
2211		sbi->s_ext_extents++;
2212		if (ee_len < sbi->s_ext_min)
2213			sbi->s_ext_min = ee_len;
2214		if (ee_len > sbi->s_ext_max)
2215			sbi->s_ext_max = ee_len;
2216		if (ext_depth(inode) > sbi->s_depth_max)
2217			sbi->s_depth_max = ext_depth(inode);
2218		spin_unlock(&sbi->s_ext_stats_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2219	}
 
 
 
 
 
 
 
 
 
 
 
 
2220#endif
2221	if (from >= le32_to_cpu(ex->ee_block)
2222	    && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2223		/* tail removal */
2224		ext4_lblk_t num;
2225		ext4_fsblk_t start;
2226
2227		num = le32_to_cpu(ex->ee_block) + ee_len - from;
2228		start = ext4_ext_pblock(ex) + ee_len - num;
2229		ext_debug("free last %u blocks starting %llu\n", num, start);
2230		ext4_free_blocks(handle, inode, NULL, start, num, flags);
2231	} else if (from == le32_to_cpu(ex->ee_block)
2232		   && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2233		/* head removal */
2234		ext4_lblk_t num;
2235		ext4_fsblk_t start;
2236
2237		num = to - from;
2238		start = ext4_ext_pblock(ex);
2239
2240		ext_debug("free first %u blocks starting %llu\n", num, start);
2241		ext4_free_blocks(handle, inode, 0, start, num, flags);
 
 
 
2242
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2243	} else {
2244		printk(KERN_INFO "strange request: removal(2) "
2245				"%u-%u from %u:%u\n",
2246				from, to, le32_to_cpu(ex->ee_block), ee_len);
2247	}
 
2248	return 0;
2249}
2250
2251
2252/*
2253 * ext4_ext_rm_leaf() Removes the extents associated with the
2254 * blocks appearing between "start" and "end", and splits the extents
2255 * if "start" and "end" appear in the same extent
2256 *
2257 * @handle: The journal handle
2258 * @inode:  The files inode
2259 * @path:   The path to the leaf
 
 
 
 
2260 * @start:  The first block to remove
2261 * @end:   The last block to remove
2262 */
2263static int
2264ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2265		struct ext4_ext_path *path, ext4_lblk_t start,
2266		ext4_lblk_t end)
 
2267{
 
2268	int err = 0, correct_index = 0;
2269	int depth = ext_depth(inode), credits;
2270	struct ext4_extent_header *eh;
2271	ext4_lblk_t a, b, block;
2272	unsigned num;
2273	ext4_lblk_t ex_ee_block;
2274	unsigned short ex_ee_len;
2275	unsigned uninitialized = 0;
2276	struct ext4_extent *ex;
2277	struct ext4_map_blocks map;
2278
2279	/* the header must be checked already in ext4_ext_remove_space() */
2280	ext_debug("truncate since %u in leaf\n", start);
2281	if (!path[depth].p_hdr)
2282		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2283	eh = path[depth].p_hdr;
2284	if (unlikely(path[depth].p_hdr == NULL)) {
2285		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2286		return -EIO;
2287	}
2288	/* find where to start removing */
2289	ex = EXT_LAST_EXTENT(eh);
 
 
2290
2291	ex_ee_block = le32_to_cpu(ex->ee_block);
2292	ex_ee_len = ext4_ext_get_actual_len(ex);
2293
 
 
2294	while (ex >= EXT_FIRST_EXTENT(eh) &&
2295			ex_ee_block + ex_ee_len > start) {
2296
2297		if (ext4_ext_is_uninitialized(ex))
2298			uninitialized = 1;
2299		else
2300			uninitialized = 0;
2301
2302		ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2303			 uninitialized, ex_ee_len);
2304		path[depth].p_ext = ex;
2305
2306		a = ex_ee_block > start ? ex_ee_block : start;
2307		b = ex_ee_block+ex_ee_len - 1 < end ?
2308			ex_ee_block+ex_ee_len - 1 : end;
2309
2310		ext_debug("  border %u:%u\n", a, b);
2311
2312		/* If this extent is beyond the end of the hole, skip it */
2313		if (end <= ex_ee_block) {
 
 
 
 
 
 
 
 
 
 
 
 
2314			ex--;
2315			ex_ee_block = le32_to_cpu(ex->ee_block);
2316			ex_ee_len = ext4_ext_get_actual_len(ex);
2317			continue;
2318		} else if (a != ex_ee_block &&
2319			b != ex_ee_block + ex_ee_len - 1) {
2320			/*
2321			 * If this is a truncate, then this condition should
2322			 * never happen because at least one of the end points
2323			 * needs to be on the edge of the extent.
2324			 */
2325			if (end == EXT_MAX_BLOCKS - 1) {
2326				ext_debug("  bad truncate %u:%u\n",
2327						start, end);
2328				block = 0;
2329				num = 0;
2330				err = -EIO;
2331				goto out;
2332			}
2333			/*
2334			 * else this is a hole punch, so the extent needs to
2335			 * be split since neither edge of the hole is on the
2336			 * extent edge
2337			 */
2338			else{
2339				map.m_pblk = ext4_ext_pblock(ex);
2340				map.m_lblk = ex_ee_block;
2341				map.m_len = b - ex_ee_block;
2342
2343				err = ext4_split_extent(handle,
2344					inode, path, &map, 0,
2345					EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
2346					EXT4_GET_BLOCKS_PRE_IO);
2347
2348				if (err < 0)
2349					goto out;
2350
2351				ex_ee_len = ext4_ext_get_actual_len(ex);
2352
2353				b = ex_ee_block+ex_ee_len - 1 < end ?
2354					ex_ee_block+ex_ee_len - 1 : end;
2355
2356				/* Then remove tail of this extent */
2357				block = ex_ee_block;
2358				num = a - block;
2359			}
2360		} else if (a != ex_ee_block) {
2361			/* remove tail of the extent */
2362			block = ex_ee_block;
2363			num = a - block;
2364		} else if (b != ex_ee_block + ex_ee_len - 1) {
2365			/* remove head of the extent */
2366			block = b;
2367			num =  ex_ee_block + ex_ee_len - b;
2368
2369			/*
2370			 * If this is a truncate, this condition
2371			 * should never happen
2372			 */
2373			if (end == EXT_MAX_BLOCKS - 1) {
2374				ext_debug("  bad truncate %u:%u\n",
2375					start, end);
2376				err = -EIO;
2377				goto out;
2378			}
2379		} else {
2380			/* remove whole extent: excellent! */
2381			block = ex_ee_block;
2382			num = 0;
2383			if (a != ex_ee_block) {
2384				ext_debug("  bad truncate %u:%u\n",
2385					start, end);
2386				err = -EIO;
2387				goto out;
2388			}
2389
2390			if (b != ex_ee_block + ex_ee_len - 1) {
2391				ext_debug("  bad truncate %u:%u\n",
2392					start, end);
2393				err = -EIO;
2394				goto out;
2395			}
2396		}
2397
2398		/*
2399		 * 3 for leaf, sb, and inode plus 2 (bmap and group
2400		 * descriptor) for each block group; assume two block
2401		 * groups plus ex_ee_len/blocks_per_block_group for
2402		 * the worst case
2403		 */
2404		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2405		if (ex == EXT_FIRST_EXTENT(eh)) {
2406			correct_index = 1;
2407			credits += (ext_depth(inode)) + 1;
2408		}
2409		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2410
2411		err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2412		if (err)
 
 
 
 
 
 
 
 
 
 
 
 
2413			goto out;
 
2414
2415		err = ext4_ext_get_access(handle, inode, path + depth);
2416		if (err)
2417			goto out;
2418
2419		err = ext4_remove_blocks(handle, inode, ex, a, b);
2420		if (err)
2421			goto out;
2422
2423		if (num == 0) {
2424			/* this extent is removed; mark slot entirely unused */
2425			ext4_ext_store_pblock(ex, 0);
2426		} else if (block != ex_ee_block) {
2427			/*
2428			 * If this was a head removal, then we need to update
2429			 * the physical block since it is now at a different
2430			 * location
2431			 */
2432			ext4_ext_store_pblock(ex, ext4_ext_pblock(ex) + (b-a));
2433		}
2434
2435		ex->ee_block = cpu_to_le32(block);
2436		ex->ee_len = cpu_to_le16(num);
2437		/*
2438		 * Do not mark uninitialized if all the blocks in the
2439		 * extent have been removed.
2440		 */
2441		if (uninitialized && num)
2442			ext4_ext_mark_uninitialized(ex);
2443
2444		err = ext4_ext_dirty(handle, inode, path + depth);
2445		if (err)
2446			goto out;
2447
2448		/*
2449		 * If the extent was completely released,
2450		 * we need to remove it from the leaf
2451		 */
2452		if (num == 0) {
2453			if (end != EXT_MAX_BLOCKS - 1) {
2454				/*
2455				 * For hole punching, we need to scoot all the
2456				 * extents up when an extent is removed so that
2457				 * we dont have blank extents in the middle
2458				 */
2459				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2460					sizeof(struct ext4_extent));
2461
2462				/* Now get rid of the one at the end */
2463				memset(EXT_LAST_EXTENT(eh), 0,
2464					sizeof(struct ext4_extent));
2465			}
2466			le16_add_cpu(&eh->eh_entries, -1);
2467		}
2468
2469		ext_debug("new extent: %u:%u:%llu\n", block, num,
 
 
 
 
2470				ext4_ext_pblock(ex));
2471		ex--;
2472		ex_ee_block = le32_to_cpu(ex->ee_block);
2473		ex_ee_len = ext4_ext_get_actual_len(ex);
2474	}
2475
2476	if (correct_index && eh->eh_entries)
2477		err = ext4_ext_correct_indexes(handle, inode, path);
2478
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2479	/* if this leaf is free, then we should
2480	 * remove it from index block above */
2481	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2482		err = ext4_ext_rm_idx(handle, inode, path + depth);
2483
2484out:
2485	return err;
2486}
2487
2488/*
2489 * ext4_ext_more_to_rm:
2490 * returns 1 if current index has to be freed (even partial)
2491 */
2492static int
2493ext4_ext_more_to_rm(struct ext4_ext_path *path)
2494{
2495	BUG_ON(path->p_idx == NULL);
2496
2497	if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2498		return 0;
2499
2500	/*
2501	 * if truncate on deeper level happened, it wasn't partial,
2502	 * so we have to consider current index for truncation
2503	 */
2504	if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2505		return 0;
2506	return 1;
2507}
2508
2509static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
 
2510{
2511	struct super_block *sb = inode->i_sb;
2512	int depth = ext_depth(inode);
2513	struct ext4_ext_path *path;
 
2514	handle_t *handle;
2515	int i, err;
2516
2517	ext_debug("truncate since %u\n", start);
 
 
 
 
2518
2519	/* probably first extent we're gonna free will be last in block */
2520	handle = ext4_journal_start(inode, depth + 1);
 
 
2521	if (IS_ERR(handle))
2522		return PTR_ERR(handle);
2523
2524again:
2525	ext4_ext_invalidate_cache(inode);
2526
2527	/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2528	 * We start scanning from right side, freeing all the blocks
2529	 * after i_size and walking into the tree depth-wise.
2530	 */
2531	depth = ext_depth(inode);
2532	path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
2533	if (path == NULL) {
2534		ext4_journal_stop(handle);
2535		return -ENOMEM;
2536	}
2537	path[0].p_depth = depth;
2538	path[0].p_hdr = ext_inode_hdr(inode);
2539	if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2540		err = -EIO;
2541		goto out;
 
 
 
 
 
 
 
 
 
 
2542	}
2543	i = err = 0;
2544
2545	while (i >= 0 && err == 0) {
2546		if (i == depth) {
2547			/* this is leaf block */
2548			err = ext4_ext_rm_leaf(handle, inode, path,
2549					start, EXT_MAX_BLOCKS - 1);
2550			/* root level has p_bh == NULL, brelse() eats this */
2551			brelse(path[i].p_bh);
2552			path[i].p_bh = NULL;
2553			i--;
2554			continue;
2555		}
2556
2557		/* this is index block */
2558		if (!path[i].p_hdr) {
2559			ext_debug("initialize header\n");
2560			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2561		}
2562
2563		if (!path[i].p_idx) {
2564			/* this level hasn't been touched yet */
2565			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2566			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2567			ext_debug("init index ptr: hdr 0x%p, num %d\n",
2568				  path[i].p_hdr,
2569				  le16_to_cpu(path[i].p_hdr->eh_entries));
2570		} else {
2571			/* we were already here, see at next index */
2572			path[i].p_idx--;
2573		}
2574
2575		ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2576				i, EXT_FIRST_INDEX(path[i].p_hdr),
2577				path[i].p_idx);
2578		if (ext4_ext_more_to_rm(path + i)) {
2579			struct buffer_head *bh;
2580			/* go to the next level */
2581			ext_debug("move to level %d (block %llu)\n",
2582				  i + 1, ext4_idx_pblock(path[i].p_idx));
2583			memset(path + i + 1, 0, sizeof(*path));
2584			bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
2585			if (!bh) {
 
 
2586				/* should we reset i_size? */
2587				err = -EIO;
2588				break;
2589			}
 
 
 
2590			if (WARN_ON(i + 1 > depth)) {
2591				err = -EIO;
2592				break;
2593			}
2594			if (ext4_ext_check(inode, ext_block_hdr(bh),
2595							depth - i - 1)) {
2596				err = -EIO;
2597				break;
2598			}
2599			path[i + 1].p_bh = bh;
2600
2601			/* save actual number of indexes since this
2602			 * number is changed at the next iteration */
2603			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2604			i++;
2605		} else {
2606			/* we finished processing this index, go up */
2607			if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2608				/* index is empty, remove it;
2609				 * handle must be already prepared by the
2610				 * truncatei_leaf() */
2611				err = ext4_ext_rm_idx(handle, inode, path + i);
2612			}
2613			/* root level has p_bh == NULL, brelse() eats this */
2614			brelse(path[i].p_bh);
2615			path[i].p_bh = NULL;
2616			i--;
2617			ext_debug("return to level %d\n", i);
2618		}
2619	}
2620
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2621	/* TODO: flexible tree reduction should be here */
2622	if (path->p_hdr->eh_entries == 0) {
2623		/*
2624		 * truncate to zero freed all the tree,
2625		 * so we need to correct eh_depth
2626		 */
2627		err = ext4_ext_get_access(handle, inode, path);
2628		if (err == 0) {
2629			ext_inode_hdr(inode)->eh_depth = 0;
2630			ext_inode_hdr(inode)->eh_max =
2631				cpu_to_le16(ext4_ext_space_root(inode, 0));
2632			err = ext4_ext_dirty(handle, inode, path);
2633		}
2634	}
2635out:
2636	ext4_ext_drop_refs(path);
2637	kfree(path);
2638	if (err == -EAGAIN)
2639		goto again;
2640	ext4_journal_stop(handle);
2641
2642	return err;
2643}
2644
2645/*
2646 * called at mount time
2647 */
2648void ext4_ext_init(struct super_block *sb)
2649{
2650	/*
2651	 * possible initialization would be here
2652	 */
2653
2654	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2655#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
2656		printk(KERN_INFO "EXT4-fs: file extents enabled");
2657#ifdef AGGRESSIVE_TEST
2658		printk(", aggressive tests");
2659#endif
2660#ifdef CHECK_BINSEARCH
2661		printk(", check binsearch");
2662#endif
2663#ifdef EXTENTS_STATS
2664		printk(", stats");
2665#endif
2666		printk("\n");
2667#endif
2668#ifdef EXTENTS_STATS
2669		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2670		EXT4_SB(sb)->s_ext_min = 1 << 30;
2671		EXT4_SB(sb)->s_ext_max = 0;
2672#endif
2673	}
2674}
2675
2676/*
2677 * called at umount time
2678 */
2679void ext4_ext_release(struct super_block *sb)
2680{
2681	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2682		return;
2683
2684#ifdef EXTENTS_STATS
2685	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2686		struct ext4_sb_info *sbi = EXT4_SB(sb);
2687		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2688			sbi->s_ext_blocks, sbi->s_ext_extents,
2689			sbi->s_ext_blocks / sbi->s_ext_extents);
2690		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2691			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2692	}
2693#endif
2694}
2695
2696/* FIXME!! we need to try to merge to left or right after zero-out  */
2697static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2698{
 
2699	ext4_fsblk_t ee_pblock;
2700	unsigned int ee_len;
2701	int ret;
2702
 
2703	ee_len    = ext4_ext_get_actual_len(ex);
2704	ee_pblock = ext4_ext_pblock(ex);
2705
2706	ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
2707	if (ret > 0)
2708		ret = 0;
2709
2710	return ret;
 
2711}
2712
2713/*
2714 * used by extent splitting.
2715 */
2716#define EXT4_EXT_MAY_ZEROOUT	0x1  /* safe to zeroout if split fails \
2717					due to ENOSPC */
2718#define EXT4_EXT_MARK_UNINIT1	0x2  /* mark first half uninitialized */
2719#define EXT4_EXT_MARK_UNINIT2	0x4  /* mark second half uninitialized */
 
 
 
 
2720
2721/*
2722 * ext4_split_extent_at() splits an extent at given block.
2723 *
2724 * @handle: the journal handle
2725 * @inode: the file inode
2726 * @path: the path to the extent
2727 * @split: the logical block where the extent is splitted.
2728 * @split_flags: indicates if the extent could be zeroout if split fails, and
2729 *		 the states(init or uninit) of new extents.
2730 * @flags: flags used to insert new extent to extent tree.
2731 *
2732 *
2733 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
2734 * of which are deterimined by split_flag.
2735 *
2736 * There are two cases:
2737 *  a> the extent are splitted into two extent.
2738 *  b> split is not needed, and just mark the extent.
2739 *
2740 * return 0 on success.
2741 */
2742static int ext4_split_extent_at(handle_t *handle,
2743			     struct inode *inode,
2744			     struct ext4_ext_path *path,
2745			     ext4_lblk_t split,
2746			     int split_flag,
2747			     int flags)
2748{
2749	ext4_fsblk_t newblock;
2750	ext4_lblk_t ee_block;
2751	struct ext4_extent *ex, newex, orig_ex;
2752	struct ext4_extent *ex2 = NULL;
2753	unsigned int ee_len, depth;
2754	int err = 0;
2755
2756	ext_debug("ext4_split_extents_at: inode %lu, logical"
2757		"block %llu\n", inode->i_ino, (unsigned long long)split);
 
 
2758
2759	ext4_ext_show_leaf(inode, path);
2760
2761	depth = ext_depth(inode);
2762	ex = path[depth].p_ext;
2763	ee_block = le32_to_cpu(ex->ee_block);
2764	ee_len = ext4_ext_get_actual_len(ex);
2765	newblock = split - ee_block + ext4_ext_pblock(ex);
2766
2767	BUG_ON(split < ee_block || split >= (ee_block + ee_len));
 
 
 
 
2768
2769	err = ext4_ext_get_access(handle, inode, path + depth);
2770	if (err)
2771		goto out;
2772
2773	if (split == ee_block) {
2774		/*
2775		 * case b: block @split is the block that the extent begins with
2776		 * then we just change the state of the extent, and splitting
2777		 * is not needed.
2778		 */
2779		if (split_flag & EXT4_EXT_MARK_UNINIT2)
2780			ext4_ext_mark_uninitialized(ex);
2781		else
2782			ext4_ext_mark_initialized(ex);
2783
2784		if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
2785			ext4_ext_try_to_merge(inode, path, ex);
2786
2787		err = ext4_ext_dirty(handle, inode, path + depth);
2788		goto out;
2789	}
2790
2791	/* case a */
2792	memcpy(&orig_ex, ex, sizeof(orig_ex));
2793	ex->ee_len = cpu_to_le16(split - ee_block);
2794	if (split_flag & EXT4_EXT_MARK_UNINIT1)
2795		ext4_ext_mark_uninitialized(ex);
2796
2797	/*
2798	 * path may lead to new leaf, not to original leaf any more
2799	 * after ext4_ext_insert_extent() returns,
2800	 */
2801	err = ext4_ext_dirty(handle, inode, path + depth);
2802	if (err)
2803		goto fix_extent_len;
2804
2805	ex2 = &newex;
2806	ex2->ee_block = cpu_to_le32(split);
2807	ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
2808	ext4_ext_store_pblock(ex2, newblock);
2809	if (split_flag & EXT4_EXT_MARK_UNINIT2)
2810		ext4_ext_mark_uninitialized(ex2);
2811
2812	err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2813	if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2814		err = ext4_ext_zeroout(inode, &orig_ex);
2815		if (err)
2816			goto fix_extent_len;
2817		/* update the extent length and mark as initialized */
2818		ex->ee_len = cpu_to_le32(ee_len);
2819		ext4_ext_try_to_merge(inode, path, ex);
2820		err = ext4_ext_dirty(handle, inode, path + depth);
2821		goto out;
2822	} else if (err)
2823		goto fix_extent_len;
2824
2825out:
2826	ext4_ext_show_leaf(inode, path);
2827	return err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2828
2829fix_extent_len:
2830	ex->ee_len = orig_ex.ee_len;
2831	ext4_ext_dirty(handle, inode, path + depth);
2832	return err;
 
 
 
 
 
 
 
 
 
 
2833}
2834
2835/*
2836 * ext4_split_extents() splits an extent and mark extent which is covered
2837 * by @map as split_flags indicates
2838 *
2839 * It may result in splitting the extent into multiple extents (upto three)
2840 * There are three possibilities:
2841 *   a> There is no split required
2842 *   b> Splits in two extents: Split is happening at either end of the extent
2843 *   c> Splits in three extents: Somone is splitting in middle of the extent
2844 *
2845 */
2846static int ext4_split_extent(handle_t *handle,
2847			      struct inode *inode,
2848			      struct ext4_ext_path *path,
2849			      struct ext4_map_blocks *map,
2850			      int split_flag,
2851			      int flags)
2852{
2853	ext4_lblk_t ee_block;
2854	struct ext4_extent *ex;
2855	unsigned int ee_len, depth;
2856	int err = 0;
2857	int uninitialized;
2858	int split_flag1, flags1;
2859
2860	depth = ext_depth(inode);
2861	ex = path[depth].p_ext;
2862	ee_block = le32_to_cpu(ex->ee_block);
2863	ee_len = ext4_ext_get_actual_len(ex);
2864	uninitialized = ext4_ext_is_uninitialized(ex);
2865
2866	if (map->m_lblk + map->m_len < ee_block + ee_len) {
2867		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2868			      EXT4_EXT_MAY_ZEROOUT : 0;
2869		flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
2870		if (uninitialized)
2871			split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
2872				       EXT4_EXT_MARK_UNINIT2;
2873		err = ext4_split_extent_at(handle, inode, path,
 
 
2874				map->m_lblk + map->m_len, split_flag1, flags1);
2875		if (err)
2876			goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2877	}
2878
2879	ext4_ext_drop_refs(path);
2880	path = ext4_ext_find_extent(inode, map->m_lblk, path);
2881	if (IS_ERR(path))
2882		return PTR_ERR(path);
2883
2884	if (map->m_lblk >= ee_block) {
2885		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2886			      EXT4_EXT_MAY_ZEROOUT : 0;
2887		if (uninitialized)
2888			split_flag1 |= EXT4_EXT_MARK_UNINIT1;
2889		if (split_flag & EXT4_EXT_MARK_UNINIT2)
2890			split_flag1 |= EXT4_EXT_MARK_UNINIT2;
2891		err = ext4_split_extent_at(handle, inode, path,
2892				map->m_lblk, split_flag1, flags);
2893		if (err)
2894			goto out;
2895	}
2896
 
 
 
 
 
 
2897	ext4_ext_show_leaf(inode, path);
2898out:
2899	return err ? err : map->m_len;
2900}
2901
2902#define EXT4_EXT_ZERO_LEN 7
2903/*
2904 * This function is called by ext4_ext_map_blocks() if someone tries to write
2905 * to an uninitialized extent. It may result in splitting the uninitialized
2906 * extent into multiple extents (up to three - one initialized and two
2907 * uninitialized).
2908 * There are three possibilities:
2909 *   a> There is no split required: Entire extent should be initialized
2910 *   b> Splits in two extents: Write is happening at either end of the extent
2911 *   c> Splits in three extents: Somone is writing in middle of the extent
2912 */
2913static int ext4_ext_convert_to_initialized(handle_t *handle,
2914					   struct inode *inode,
2915					   struct ext4_map_blocks *map,
2916					   struct ext4_ext_path *path)
 
 
 
 
 
 
 
 
 
 
2917{
 
 
2918	struct ext4_map_blocks split_map;
2919	struct ext4_extent zero_ex;
2920	struct ext4_extent *ex;
2921	ext4_lblk_t ee_block, eof_block;
2922	unsigned int allocated, ee_len, depth;
2923	int err = 0;
2924	int split_flag = 0;
 
2925
2926	ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
2927		"block %llu, max_blocks %u\n", inode->i_ino,
2928		(unsigned long long)map->m_lblk, map->m_len);
2929
2930	eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
2931		inode->i_sb->s_blocksize_bits;
2932	if (eof_block < map->m_lblk + map->m_len)
2933		eof_block = map->m_lblk + map->m_len;
 
2934
2935	depth = ext_depth(inode);
 
2936	ex = path[depth].p_ext;
2937	ee_block = le32_to_cpu(ex->ee_block);
2938	ee_len = ext4_ext_get_actual_len(ex);
2939	allocated = ee_len - (map->m_lblk - ee_block);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2940
2941	WARN_ON(map->m_lblk < ee_block);
2942	/*
2943	 * It is safe to convert extent to initialized via explicit
2944	 * zeroout only if extent is fully insde i_size or new_size.
2945	 */
2946	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
2947
2948	/* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
2949	if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
2950	    (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2951		err = ext4_ext_zeroout(inode, ex);
2952		if (err)
2953			goto out;
2954
2955		err = ext4_ext_get_access(handle, inode, path + depth);
2956		if (err)
2957			goto out;
2958		ext4_ext_mark_initialized(ex);
2959		ext4_ext_try_to_merge(inode, path, ex);
2960		err = ext4_ext_dirty(handle, inode, path + depth);
2961		goto out;
2962	}
2963
2964	/*
2965	 * four cases:
2966	 * 1. split the extent into three extents.
2967	 * 2. split the extent into two extents, zeroout the first half.
2968	 * 3. split the extent into two extents, zeroout the second half.
 
 
2969	 * 4. split the extent into two extents with out zeroout.
 
 
2970	 */
2971	split_map.m_lblk = map->m_lblk;
2972	split_map.m_len = map->m_len;
2973
2974	if (allocated > map->m_len) {
2975		if (allocated <= EXT4_EXT_ZERO_LEN &&
2976		    (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2977			/* case 3 */
2978			zero_ex.ee_block =
2979					 cpu_to_le32(map->m_lblk);
2980			zero_ex.ee_len = cpu_to_le16(allocated);
2981			ext4_ext_store_pblock(&zero_ex,
2982				ext4_ext_pblock(ex) + map->m_lblk - ee_block);
2983			err = ext4_ext_zeroout(inode, &zero_ex);
 
 
2984			if (err)
2985				goto out;
2986			split_map.m_lblk = map->m_lblk;
2987			split_map.m_len = allocated;
2988		} else if ((map->m_lblk - ee_block + map->m_len <
2989			   EXT4_EXT_ZERO_LEN) &&
2990			   (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2991			/* case 2 */
2992			if (map->m_lblk != ee_block) {
2993				zero_ex.ee_block = ex->ee_block;
2994				zero_ex.ee_len = cpu_to_le16(map->m_lblk -
2995							ee_block);
2996				ext4_ext_store_pblock(&zero_ex,
2997						      ext4_ext_pblock(ex));
2998				err = ext4_ext_zeroout(inode, &zero_ex);
2999				if (err)
3000					goto out;
3001			}
3002
 
3003			split_map.m_lblk = ee_block;
3004			split_map.m_len = map->m_lblk - ee_block + map->m_len;
3005			allocated = map->m_len;
3006		}
3007	}
3008
3009	allocated = ext4_split_extent(handle, inode, path,
3010				       &split_map, split_flag, 0);
3011	if (allocated < 0)
3012		err = allocated;
3013
3014out:
3015	return err ? err : allocated;
 
 
 
 
 
 
 
3016}
3017
3018/*
3019 * This function is called by ext4_ext_map_blocks() from
3020 * ext4_get_blocks_dio_write() when DIO to write
3021 * to an uninitialized extent.
3022 *
3023 * Writing to an uninitialized extent may result in splitting the uninitialized
3024 * extent into multiple /initialized uninitialized extents (up to three)
3025 * There are three possibilities:
3026 *   a> There is no split required: Entire extent should be uninitialized
3027 *   b> Splits in two extents: Write is happening at either end of the extent
3028 *   c> Splits in three extents: Somone is writing in middle of the extent
3029 *
 
 
3030 * One of more index blocks maybe needed if the extent tree grow after
3031 * the uninitialized extent split. To prevent ENOSPC occur at the IO
3032 * complete, we need to split the uninitialized extent before DIO submit
3033 * the IO. The uninitialized extent called at this time will be split
3034 * into three uninitialized extent(at most). After IO complete, the part
3035 * being filled will be convert to initialized by the end_io callback function
3036 * via ext4_convert_unwritten_extents().
3037 *
3038 * Returns the size of uninitialized extent to be written on success.
 
 
3039 */
3040static int ext4_split_unwritten_extents(handle_t *handle,
3041					struct inode *inode,
3042					struct ext4_map_blocks *map,
3043					struct ext4_ext_path *path,
3044					int flags)
3045{
3046	ext4_lblk_t eof_block;
3047	ext4_lblk_t ee_block;
3048	struct ext4_extent *ex;
3049	unsigned int ee_len;
3050	int split_flag = 0, depth;
3051
3052	ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3053		"block %llu, max_blocks %u\n", inode->i_ino,
3054		(unsigned long long)map->m_lblk, map->m_len);
3055
3056	eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3057		inode->i_sb->s_blocksize_bits;
3058	if (eof_block < map->m_lblk + map->m_len)
3059		eof_block = map->m_lblk + map->m_len;
3060	/*
3061	 * It is safe to convert extent to initialized via explicit
3062	 * zeroout only if extent is fully insde i_size or new_size.
3063	 */
3064	depth = ext_depth(inode);
3065	ex = path[depth].p_ext;
3066	ee_block = le32_to_cpu(ex->ee_block);
3067	ee_len = ext4_ext_get_actual_len(ex);
3068
3069	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3070	split_flag |= EXT4_EXT_MARK_UNINIT2;
3071
 
 
 
 
 
 
3072	flags |= EXT4_GET_BLOCKS_PRE_IO;
3073	return ext4_split_extent(handle, inode, path, map, split_flag, flags);
 
3074}
3075
3076static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3077					      struct inode *inode,
3078					      struct ext4_ext_path *path)
 
3079{
3080	struct ext4_extent *ex;
 
 
3081	int depth;
3082	int err = 0;
3083
3084	depth = ext_depth(inode);
3085	ex = path[depth].p_ext;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3086
3087	ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3088		"block %llu, max_blocks %u\n", inode->i_ino,
3089		(unsigned long long)le32_to_cpu(ex->ee_block),
3090		ext4_ext_get_actual_len(ex));
 
 
3091
3092	err = ext4_ext_get_access(handle, inode, path + depth);
3093	if (err)
3094		goto out;
3095	/* first mark the extent as initialized */
3096	ext4_ext_mark_initialized(ex);
3097
3098	/* note: ext4_ext_correct_indexes() isn't needed here because
3099	 * borders are not changed
3100	 */
3101	ext4_ext_try_to_merge(inode, path, ex);
3102
3103	/* Mark modified extent as dirty */
3104	err = ext4_ext_dirty(handle, inode, path + depth);
3105out:
 
 
3106	ext4_ext_show_leaf(inode, path);
3107	return err;
3108}
3109
3110static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3111			sector_t block, int count)
3112{
3113	int i;
3114	for (i = 0; i < count; i++)
3115                unmap_underlying_metadata(bdev, block + i);
3116}
3117
3118/*
3119 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3120 */
3121static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3122			      ext4_lblk_t lblk,
3123			      struct ext4_ext_path *path,
3124			      unsigned int len)
3125{
3126	int i, depth;
3127	struct ext4_extent_header *eh;
3128	struct ext4_extent *last_ex;
 
 
3129
3130	if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3131		return 0;
 
 
 
 
3132
3133	depth = ext_depth(inode);
3134	eh = path[depth].p_hdr;
 
 
3135
3136	if (unlikely(!eh->eh_entries)) {
3137		EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
3138				 "EOFBLOCKS_FL set");
3139		return -EIO;
3140	}
3141	last_ex = EXT_LAST_EXTENT(eh);
3142	/*
3143	 * We should clear the EOFBLOCKS_FL flag if we are writing the
3144	 * last block in the last extent in the file.  We test this by
3145	 * first checking to see if the caller to
3146	 * ext4_ext_get_blocks() was interested in the last block (or
3147	 * a block beyond the last block) in the current extent.  If
3148	 * this turns out to be false, we can bail out from this
3149	 * function immediately.
3150	 */
3151	if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3152	    ext4_ext_get_actual_len(last_ex))
3153		return 0;
3154	/*
3155	 * If the caller does appear to be planning to write at or
3156	 * beyond the end of the current extent, we then test to see
3157	 * if the current extent is the last extent in the file, by
3158	 * checking to make sure it was reached via the rightmost node
3159	 * at each level of the tree.
 
 
 
 
 
 
3160	 */
3161	for (i = depth-1; i >= 0; i--)
3162		if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3163			return 0;
3164	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3165	return ext4_mark_inode_dirty(handle, inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3166}
3167
3168static int
3169ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3170			struct ext4_map_blocks *map,
3171			struct ext4_ext_path *path, int flags,
3172			unsigned int allocated, ext4_fsblk_t newblock)
3173{
3174	int ret = 0;
3175	int err = 0;
3176	ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3177
3178	ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
3179		  "block %llu, max_blocks %u, flags %d, allocated %u",
3180		  inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3181		  flags, allocated);
3182	ext4_ext_show_leaf(inode, path);
3183
3184	/* get_block() before submit the IO, split the extent */
3185	if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3186		ret = ext4_split_unwritten_extents(handle, inode, map,
3187						   path, flags);
 
 
 
 
 
 
 
 
 
 
 
3188		/*
3189		 * Flag the inode(non aio case) or end_io struct (aio case)
3190		 * that this IO needs to conversion to written when IO is
3191		 * completed
3192		 */
3193		if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3194			io->flag = EXT4_IO_END_UNWRITTEN;
3195			atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3196		} else
3197			ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3198		if (ext4_should_dioread_nolock(inode))
3199			map->m_flags |= EXT4_MAP_UNINIT;
 
3200		goto out;
3201	}
3202	/* IO end_io complete, convert the filled extent to written */
3203	if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3204		ret = ext4_convert_unwritten_extents_endio(handle, inode,
3205							path);
3206		if (ret >= 0) {
3207			ext4_update_inode_fsync_trans(handle, inode, 1);
3208			err = check_eofblocks_fl(handle, inode, map->m_lblk,
3209						 path, map->m_len);
3210		} else
3211			err = ret;
3212		goto out2;
3213	}
3214	/* buffered IO case */
3215	/*
3216	 * repeat fallocate creation request
3217	 * we already have an unwritten extent
3218	 */
3219	if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
 
3220		goto map_out;
 
3221
3222	/* buffered READ or buffered write_begin() lookup */
3223	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3224		/*
3225		 * We have blocks reserved already.  We
3226		 * return allocated blocks so that delalloc
3227		 * won't do block reservation for us.  But
3228		 * the buffer head will be unmapped so that
3229		 * a read from the block returns 0s.
3230		 */
3231		map->m_flags |= EXT4_MAP_UNWRITTEN;
3232		goto out1;
3233	}
3234
3235	/* buffered write, writepage time, convert*/
3236	ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
3237	if (ret >= 0) {
3238		ext4_update_inode_fsync_trans(handle, inode, 1);
3239		err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3240					 map->m_len);
3241		if (err < 0)
3242			goto out2;
3243	}
3244
3245out:
3246	if (ret <= 0) {
3247		err = ret;
3248		goto out2;
3249	} else
3250		allocated = ret;
3251	map->m_flags |= EXT4_MAP_NEW;
3252	/*
3253	 * if we allocated more blocks than requested
3254	 * we need to make sure we unmap the extra block
3255	 * allocated. The actual needed block will get
3256	 * unmapped later when we find the buffer_head marked
3257	 * new.
3258	 */
3259	if (allocated > map->m_len) {
3260		unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3261					newblock + map->m_len,
3262					allocated - map->m_len);
3263		allocated = map->m_len;
3264	}
3265
3266	/*
3267	 * If we have done fallocate with the offset that is already
3268	 * delayed allocated, we would have block reservation
3269	 * and quota reservation done in the delayed write path.
3270	 * But fallocate would have already updated quota and block
3271	 * count for this offset. So cancel these reservation
3272	 */
3273	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3274		ext4_da_update_reserve_space(inode, allocated, 0);
 
 
 
 
3275
 
 
3276map_out:
3277	map->m_flags |= EXT4_MAP_MAPPED;
3278out1:
3279	if (allocated > map->m_len)
3280		allocated = map->m_len;
3281	ext4_ext_show_leaf(inode, path);
3282	map->m_pblk = newblock;
3283	map->m_len = allocated;
3284out2:
3285	if (path) {
3286		ext4_ext_drop_refs(path);
3287		kfree(path);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3288	}
3289	return err ? err : allocated;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3290}
3291
3292/*
3293 * Block allocation/map/preallocation routine for extents based files
3294 *
3295 *
3296 * Need to be called with
3297 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3298 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3299 *
3300 * return > 0, number of of blocks already mapped/allocated
3301 *          if create == 0 and these are pre-allocated blocks
3302 *          	buffer head is unmapped
3303 *          otherwise blocks are mapped
3304 *
3305 * return = 0, if plain look up failed (blocks have not been allocated)
3306 *          buffer head is unmapped
3307 *
3308 * return < 0, error case.
3309 */
3310int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
3311			struct ext4_map_blocks *map, int flags)
3312{
3313	struct ext4_ext_path *path = NULL;
3314	struct ext4_extent newex, *ex;
3315	ext4_fsblk_t newblock = 0;
3316	int err = 0, depth, ret;
3317	unsigned int allocated = 0;
3318	unsigned int punched_out = 0;
3319	unsigned int result = 0;
3320	struct ext4_allocation_request ar;
3321	ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3322	struct ext4_map_blocks punch_map;
3323
3324	ext_debug("blocks %u/%u requested for inode %lu\n",
3325		  map->m_lblk, map->m_len, inode->i_ino);
3326	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
3327
3328	/* check in cache */
3329	if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) &&
3330		ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
3331		if (!newex.ee_start_lo && !newex.ee_start_hi) {
3332			if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3333				/*
3334				 * block isn't allocated yet and
3335				 * user doesn't want to allocate it
3336				 */
3337				goto out2;
3338			}
3339			/* we should allocate requested block */
3340		} else {
3341			/* block is already allocated */
3342			newblock = map->m_lblk
3343				   - le32_to_cpu(newex.ee_block)
3344				   + ext4_ext_pblock(&newex);
3345			/* number of remaining blocks in the extent */
3346			allocated = ext4_ext_get_actual_len(&newex) -
3347				(map->m_lblk - le32_to_cpu(newex.ee_block));
3348			goto out;
3349		}
3350	}
3351
3352	/* find extent for this block */
3353	path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
3354	if (IS_ERR(path)) {
3355		err = PTR_ERR(path);
3356		path = NULL;
3357		goto out2;
3358	}
3359
3360	depth = ext_depth(inode);
3361
3362	/*
3363	 * consistent leaf must not be empty;
3364	 * this situation is possible, though, _during_ tree modification;
3365	 * this is why assert can't be put in ext4_ext_find_extent()
3366	 */
3367	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
3368		EXT4_ERROR_INODE(inode, "bad extent address "
3369				 "lblock: %lu, depth: %d pblock %lld",
3370				 (unsigned long) map->m_lblk, depth,
3371				 path[depth].p_block);
3372		err = -EIO;
3373		goto out2;
3374	}
3375
3376	ex = path[depth].p_ext;
3377	if (ex) {
3378		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3379		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3380		unsigned short ee_len;
3381
 
3382		/*
3383		 * Uninitialized extents are treated as holes, except that
3384		 * we split out initialized portions during a write.
3385		 */
3386		ee_len = ext4_ext_get_actual_len(ex);
 
 
 
3387		/* if found extent covers block, simply return it */
3388		if (in_range(map->m_lblk, ee_block, ee_len)) {
3389			newblock = map->m_lblk - ee_block + ee_start;
3390			/* number of remaining blocks in the extent */
3391			allocated = ee_len - (map->m_lblk - ee_block);
3392			ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
3393				  ee_block, ee_len, newblock);
3394
3395			if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
3396				/*
3397				 * Do not put uninitialized extent
3398				 * in the cache
3399				 */
3400				if (!ext4_ext_is_uninitialized(ex)) {
3401					ext4_ext_put_in_cache(inode, ee_block,
3402						ee_len, ee_start);
3403					goto out;
3404				}
3405				ret = ext4_ext_handle_uninitialized_extents(
3406					handle, inode, map, path, flags,
3407					allocated, newblock);
3408				return ret;
3409			}
3410
3411			/*
3412			 * Punch out the map length, but only to the
3413			 * end of the extent
3414			 */
3415			punched_out = allocated < map->m_len ?
3416				allocated : map->m_len;
3417
3418			/*
3419			 * Sense extents need to be converted to
3420			 * uninitialized, they must fit in an
3421			 * uninitialized extent
3422			 */
3423			if (punched_out > EXT_UNINIT_MAX_LEN)
3424				punched_out = EXT_UNINIT_MAX_LEN;
3425
3426			punch_map.m_lblk = map->m_lblk;
3427			punch_map.m_pblk = newblock;
3428			punch_map.m_len = punched_out;
3429			punch_map.m_flags = 0;
3430
3431			/* Check to see if the extent needs to be split */
3432			if (punch_map.m_len != ee_len ||
3433				punch_map.m_lblk != ee_block) {
3434
3435				ret = ext4_split_extent(handle, inode,
3436				path, &punch_map, 0,
3437				EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
3438				EXT4_GET_BLOCKS_PRE_IO);
3439
3440				if (ret < 0) {
3441					err = ret;
3442					goto out2;
3443				}
3444				/*
3445				 * find extent for the block at
3446				 * the start of the hole
3447				 */
3448				ext4_ext_drop_refs(path);
3449				kfree(path);
3450
3451				path = ext4_ext_find_extent(inode,
3452				map->m_lblk, NULL);
3453				if (IS_ERR(path)) {
3454					err = PTR_ERR(path);
3455					path = NULL;
3456					goto out2;
3457				}
3458
3459				depth = ext_depth(inode);
3460				ex = path[depth].p_ext;
3461				ee_len = ext4_ext_get_actual_len(ex);
3462				ee_block = le32_to_cpu(ex->ee_block);
3463				ee_start = ext4_ext_pblock(ex);
3464
3465			}
3466
3467			ext4_ext_mark_uninitialized(ex);
3468
3469			ext4_ext_invalidate_cache(inode);
3470
3471			err = ext4_ext_rm_leaf(handle, inode, path,
3472				map->m_lblk, map->m_lblk + punched_out);
3473
3474			if (!err && path->p_hdr->eh_entries == 0) {
3475				/*
3476				 * Punch hole freed all of this sub tree,
3477				 * so we need to correct eh_depth
3478				 */
3479				err = ext4_ext_get_access(handle, inode, path);
3480				if (err == 0) {
3481					ext_inode_hdr(inode)->eh_depth = 0;
3482					ext_inode_hdr(inode)->eh_max =
3483					cpu_to_le16(ext4_ext_space_root(
3484						inode, 0));
3485
3486					err = ext4_ext_dirty(
3487						handle, inode, path);
3488				}
3489			}
3490
3491			goto out2;
 
 
 
 
 
3492		}
3493	}
3494
3495	/*
3496	 * requested block isn't allocated yet;
3497	 * we couldn't try to create block if create flag is zero
3498	 */
3499	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3500		/*
3501		 * put just found gap into cache to speed up
3502		 * subsequent requests
3503		 */
3504		ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
3505		goto out2;
 
3506	}
 
3507	/*
3508	 * Okay, we need to do block allocation.
3509	 */
 
 
 
 
 
 
 
 
 
 
 
 
 
3510
3511	/* find neighbour allocated blocks */
3512	ar.lleft = map->m_lblk;
3513	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3514	if (err)
3515		goto out2;
3516	ar.lright = map->m_lblk;
3517	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
3518	if (err)
3519		goto out2;
 
 
 
 
 
 
 
 
 
 
3520
3521	/*
3522	 * See if request is beyond maximum number of blocks we can have in
3523	 * a single extent. For an initialized extent this limit is
3524	 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
3525	 * EXT_UNINIT_MAX_LEN.
3526	 */
3527	if (map->m_len > EXT_INIT_MAX_LEN &&
3528	    !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3529		map->m_len = EXT_INIT_MAX_LEN;
3530	else if (map->m_len > EXT_UNINIT_MAX_LEN &&
3531		 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3532		map->m_len = EXT_UNINIT_MAX_LEN;
3533
3534	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
3535	newex.ee_block = cpu_to_le32(map->m_lblk);
3536	newex.ee_len = cpu_to_le16(map->m_len);
3537	err = ext4_ext_check_overlap(inode, &newex, path);
3538	if (err)
3539		allocated = ext4_ext_get_actual_len(&newex);
3540	else
3541		allocated = map->m_len;
3542
3543	/* allocate new block */
3544	ar.inode = inode;
3545	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
3546	ar.logical = map->m_lblk;
3547	ar.len = allocated;
 
 
 
 
 
 
 
 
 
 
 
3548	if (S_ISREG(inode->i_mode))
3549		ar.flags = EXT4_MB_HINT_DATA;
3550	else
3551		/* disable in-core preallocation for non-regular files */
3552		ar.flags = 0;
3553	if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
3554		ar.flags |= EXT4_MB_HINT_NOPREALLOC;
 
 
 
 
3555	newblock = ext4_mb_new_blocks(handle, &ar, &err);
3556	if (!newblock)
3557		goto out2;
3558	ext_debug("allocate new block: goal %llu, found %llu/%u\n",
3559		  ar.goal, newblock, allocated);
 
 
 
 
3560
 
3561	/* try to insert new extent into found leaf and return */
3562	ext4_ext_store_pblock(&newex, newblock);
 
3563	newex.ee_len = cpu_to_le16(ar.len);
3564	/* Mark uninitialized */
3565	if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
3566		ext4_ext_mark_uninitialized(&newex);
3567		/*
3568		 * io_end structure was created for every IO write to an
3569		 * uninitialized extent. To avoid unnecessary conversion,
3570		 * here we flag the IO that really needs the conversion.
3571		 * For non asycn direct IO case, flag the inode state
3572		 * that we need to perform conversion when IO is done.
3573		 */
3574		if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3575			if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3576				io->flag = EXT4_IO_END_UNWRITTEN;
3577				atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3578			} else
3579				ext4_set_inode_state(inode,
3580						     EXT4_STATE_DIO_UNWRITTEN);
3581		}
3582		if (ext4_should_dioread_nolock(inode))
3583			map->m_flags |= EXT4_MAP_UNINIT;
3584	}
3585
3586	err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
3587	if (!err)
3588		err = ext4_ext_insert_extent(handle, inode, path,
3589					     &newex, flags);
3590	if (err) {
3591		int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
3592			EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
3593		/* free data blocks we just allocated */
3594		/* not a good idea to call discard here directly,
3595		 * but otherwise we'd need to call it every free() */
3596		ext4_discard_preallocations(inode);
3597		ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
3598				 ext4_ext_get_actual_len(&newex), fb_flags);
3599		goto out2;
3600	}
3601
3602	/* previous routine could use block we allocated */
3603	newblock = ext4_ext_pblock(&newex);
3604	allocated = ext4_ext_get_actual_len(&newex);
3605	if (allocated > map->m_len)
3606		allocated = map->m_len;
3607	map->m_flags |= EXT4_MAP_NEW;
3608
3609	/*
3610	 * Update reserved blocks/metadata blocks after successful
3611	 * block allocation which had been deferred till now.
3612	 */
3613	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3614		ext4_da_update_reserve_space(inode, allocated, 1);
 
 
 
 
 
 
 
 
3615
3616	/*
3617	 * Cache the extent and update transaction to commit on fdatasync only
3618	 * when it is _not_ an uninitialized extent.
3619	 */
3620	if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
3621		ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
3622		ext4_update_inode_fsync_trans(handle, inode, 1);
3623	} else
3624		ext4_update_inode_fsync_trans(handle, inode, 0);
3625out:
3626	if (allocated > map->m_len)
3627		allocated = map->m_len;
3628	ext4_ext_show_leaf(inode, path);
3629	map->m_flags |= EXT4_MAP_MAPPED;
3630	map->m_pblk = newblock;
3631	map->m_len = allocated;
3632out2:
3633	if (path) {
3634		ext4_ext_drop_refs(path);
3635		kfree(path);
3636	}
3637	trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
3638		newblock, map->m_len, err ? err : allocated);
3639
3640	result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
3641			punched_out : allocated;
 
 
 
 
 
3642
3643	return err ? err : result;
 
 
3644}
3645
3646void ext4_ext_truncate(struct inode *inode)
3647{
3648	struct address_space *mapping = inode->i_mapping;
3649	struct super_block *sb = inode->i_sb;
3650	ext4_lblk_t last_block;
3651	handle_t *handle;
3652	int err = 0;
3653
3654	/*
3655	 * finish any pending end_io work so we won't run the risk of
3656	 * converting any truncated blocks to initialized later
3657	 */
3658	ext4_flush_completed_IO(inode);
3659
3660	/*
3661	 * probably first extent we're gonna free will be last in block
3662	 */
3663	err = ext4_writepage_trans_blocks(inode);
3664	handle = ext4_journal_start(inode, err);
3665	if (IS_ERR(handle))
3666		return;
3667
3668	if (inode->i_size & (sb->s_blocksize - 1))
3669		ext4_block_truncate_page(handle, mapping, inode->i_size);
3670
3671	if (ext4_orphan_add(handle, inode))
3672		goto out_stop;
3673
3674	down_write(&EXT4_I(inode)->i_data_sem);
3675	ext4_ext_invalidate_cache(inode);
3676
3677	ext4_discard_preallocations(inode);
3678
3679	/*
3680	 * TODO: optimization is possible here.
3681	 * Probably we need not scan at all,
3682	 * because page truncation is enough.
3683	 */
3684
3685	/* we have to know where to truncate from in crash case */
3686	EXT4_I(inode)->i_disksize = inode->i_size;
3687	ext4_mark_inode_dirty(handle, inode);
 
 
3688
3689	last_block = (inode->i_size + sb->s_blocksize - 1)
3690			>> EXT4_BLOCK_SIZE_BITS(sb);
3691	err = ext4_ext_remove_space(inode, last_block);
3692
3693	/* In a multi-transaction truncate, we only make the final
3694	 * transaction synchronous.
3695	 */
3696	if (IS_SYNC(inode))
3697		ext4_handle_sync(handle);
 
 
 
3698
3699	up_write(&EXT4_I(inode)->i_data_sem);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3700
3701out_stop:
3702	/*
3703	 * If this was a simple ftruncate() and the file will remain alive,
3704	 * then we need to clear up the orphan record which we created above.
3705	 * However, if this was a real unlink then we were called by
3706	 * ext4_delete_inode(), and we allow that function to clean up the
3707	 * orphan info for us.
3708	 */
3709	if (inode->i_nlink)
3710		ext4_orphan_del(handle, inode);
3711
3712	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3713	ext4_mark_inode_dirty(handle, inode);
3714	ext4_journal_stop(handle);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3715}
3716
3717static void ext4_falloc_update_inode(struct inode *inode,
3718				int mode, loff_t new_size, int update_ctime)
 
 
 
 
3719{
3720	struct timespec now;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3721
3722	if (update_ctime) {
3723		now = current_fs_time(inode->i_sb);
3724		if (!timespec_equal(&inode->i_ctime, &now))
3725			inode->i_ctime = now;
3726	}
3727	/*
3728	 * Update only when preallocation was requested beyond
3729	 * the file size.
3730	 */
3731	if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3732		if (new_size > i_size_read(inode))
3733			i_size_write(inode, new_size);
3734		if (new_size > EXT4_I(inode)->i_disksize)
3735			ext4_update_i_disksize(inode, new_size);
3736	} else {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3737		/*
3738		 * Mark that we allocate beyond EOF so the subsequent truncate
3739		 * can proceed even if the new size is the same as i_size.
3740		 */
3741		if (new_size > i_size_read(inode))
3742			ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3743	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3744
 
 
 
 
 
 
 
 
3745}
3746
3747/*
3748 * preallocate space for a file. This implements ext4's fallocate file
3749 * operation, which gets called from sys_fallocate system call.
3750 * For block-mapped files, posix_fallocate should fall back to the method
3751 * of writing zeroes to the required new blocks (the same behavior which is
3752 * expected for file systems which do not support fallocate() system call).
3753 */
3754long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
3755{
3756	struct inode *inode = file->f_path.dentry->d_inode;
3757	handle_t *handle;
3758	loff_t new_size;
3759	unsigned int max_blocks;
3760	int ret = 0;
3761	int ret2 = 0;
3762	int retries = 0;
3763	struct ext4_map_blocks map;
3764	unsigned int credits, blkbits = inode->i_blkbits;
3765
3766	/*
3767	 * currently supporting (pre)allocate mode for extent-based
3768	 * files _only_
 
 
3769	 */
3770	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 
3771		return -EOPNOTSUPP;
3772
3773	/* Return error if mode is not supported */
3774	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 
 
3775		return -EOPNOTSUPP;
3776
3777	if (mode & FALLOC_FL_PUNCH_HOLE)
3778		return ext4_punch_hole(file, offset, len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3779
 
 
 
 
3780	trace_ext4_fallocate_enter(inode, offset, len, mode);
3781	map.m_lblk = offset >> blkbits;
3782	/*
3783	 * We can't just convert len to max_blocks because
3784	 * If blocksize = 4096 offset = 3072 and len = 2048
3785	 */
3786	max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3787		- map.m_lblk;
3788	/*
3789	 * credits to insert 1 extent into extent tree
3790	 */
3791	credits = ext4_chunk_trans_blocks(inode, max_blocks);
3792	mutex_lock(&inode->i_mutex);
3793	ret = inode_newsize_ok(inode, (len + offset));
3794	if (ret) {
3795		mutex_unlock(&inode->i_mutex);
3796		trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
3797		return ret;
3798	}
3799retry:
3800	while (ret >= 0 && ret < max_blocks) {
3801		map.m_lblk = map.m_lblk + ret;
3802		map.m_len = max_blocks = max_blocks - ret;
3803		handle = ext4_journal_start(inode, credits);
3804		if (IS_ERR(handle)) {
3805			ret = PTR_ERR(handle);
3806			break;
3807		}
3808		ret = ext4_map_blocks(handle, inode, &map,
3809				      EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
3810				      EXT4_GET_BLOCKS_NO_NORMALIZE);
3811		if (ret <= 0) {
3812#ifdef EXT4FS_DEBUG
3813			WARN_ON(ret <= 0);
3814			printk(KERN_ERR "%s: ext4_ext_map_blocks "
3815				    "returned error inode#%lu, block=%u, "
3816				    "max_blocks=%u", __func__,
3817				    inode->i_ino, map.m_lblk, max_blocks);
3818#endif
3819			ext4_mark_inode_dirty(handle, inode);
3820			ret2 = ext4_journal_stop(handle);
3821			break;
3822		}
3823		if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
3824						blkbits) >> blkbits))
3825			new_size = offset + len;
3826		else
3827			new_size = ((loff_t) map.m_lblk + ret) << blkbits;
3828
3829		ext4_falloc_update_inode(inode, mode, new_size,
3830					 (map.m_flags & EXT4_MAP_NEW));
3831		ext4_mark_inode_dirty(handle, inode);
3832		ret2 = ext4_journal_stop(handle);
3833		if (ret2)
3834			break;
 
3835	}
3836	if (ret == -ENOSPC &&
3837			ext4_should_retry_alloc(inode->i_sb, &retries)) {
3838		ret = 0;
3839		goto retry;
 
 
 
 
 
 
 
 
 
 
 
3840	}
3841	mutex_unlock(&inode->i_mutex);
3842	trace_ext4_fallocate_exit(inode, offset, max_blocks,
3843				ret > 0 ? ret2 : ret);
3844	return ret > 0 ? ret2 : ret;
 
3845}
3846
3847/*
3848 * This function convert a range of blocks to written extents
3849 * The caller of this function will pass the start offset and the size.
3850 * all unwritten extents within this range will be converted to
3851 * written extents.
3852 *
3853 * This function is called from the direct IO end io call back
3854 * function, to convert the fallocated extents after IO is completed.
3855 * Returns 0 on success.
3856 */
3857int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
3858				    ssize_t len)
3859{
3860	handle_t *handle;
3861	unsigned int max_blocks;
3862	int ret = 0;
3863	int ret2 = 0;
3864	struct ext4_map_blocks map;
3865	unsigned int credits, blkbits = inode->i_blkbits;
 
3866
3867	map.m_lblk = offset >> blkbits;
3868	/*
3869	 * We can't just convert len to max_blocks because
3870	 * If blocksize = 4096 offset = 3072 and len = 2048
3871	 */
3872	max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
3873		      map.m_lblk);
3874	/*
3875	 * credits to insert 1 extent into extent tree
3876	 */
3877	credits = ext4_chunk_trans_blocks(inode, max_blocks);
3878	while (ret >= 0 && ret < max_blocks) {
3879		map.m_lblk += ret;
3880		map.m_len = (max_blocks -= ret);
3881		handle = ext4_journal_start(inode, credits);
3882		if (IS_ERR(handle)) {
3883			ret = PTR_ERR(handle);
3884			break;
 
 
 
3885		}
3886		ret = ext4_map_blocks(handle, inode, &map,
3887				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);
3888		if (ret <= 0) {
3889			WARN_ON(ret <= 0);
3890			printk(KERN_ERR "%s: ext4_ext_map_blocks "
3891				    "returned error inode#%lu, block=%u, "
3892				    "max_blocks=%u", __func__,
3893				    inode->i_ino, map.m_lblk, map.m_len);
3894		}
3895		ext4_mark_inode_dirty(handle, inode);
3896		ret2 = ext4_journal_stop(handle);
3897		if (ret <= 0 || ret2 )
 
 
 
 
3898			break;
3899	}
3900	return ret > 0 ? ret2 : ret;
3901}
3902
3903/*
3904 * Callback function called for each extent to gather FIEMAP information.
3905 */
3906static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next,
3907		       struct ext4_ext_cache *newex, struct ext4_extent *ex,
3908		       void *data)
3909{
3910	__u64	logical;
3911	__u64	physical;
3912	__u64	length;
3913	__u32	flags = 0;
3914	int		ret = 0;
3915	struct fiemap_extent_info *fieinfo = data;
3916	unsigned char blksize_bits;
3917
3918	blksize_bits = inode->i_sb->s_blocksize_bits;
3919	logical = (__u64)newex->ec_block << blksize_bits;
3920
3921	if (newex->ec_start == 0) {
3922		/*
3923		 * No extent in extent-tree contains block @newex->ec_start,
3924		 * then the block may stay in 1)a hole or 2)delayed-extent.
3925		 *
3926		 * Holes or delayed-extents are processed as follows.
3927		 * 1. lookup dirty pages with specified range in pagecache.
3928		 *    If no page is got, then there is no delayed-extent and
3929		 *    return with EXT_CONTINUE.
3930		 * 2. find the 1st mapped buffer,
3931		 * 3. check if the mapped buffer is both in the request range
3932		 *    and a delayed buffer. If not, there is no delayed-extent,
3933		 *    then return.
3934		 * 4. a delayed-extent is found, the extent will be collected.
3935		 */
3936		ext4_lblk_t	end = 0;
3937		pgoff_t		last_offset;
3938		pgoff_t		offset;
3939		pgoff_t		index;
3940		pgoff_t		start_index = 0;
3941		struct page	**pages = NULL;
3942		struct buffer_head *bh = NULL;
3943		struct buffer_head *head = NULL;
3944		unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
3945
3946		pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
3947		if (pages == NULL)
3948			return -ENOMEM;
3949
3950		offset = logical >> PAGE_SHIFT;
3951repeat:
3952		last_offset = offset;
3953		head = NULL;
3954		ret = find_get_pages_tag(inode->i_mapping, &offset,
3955					PAGECACHE_TAG_DIRTY, nr_pages, pages);
3956
3957		if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
3958			/* First time, try to find a mapped buffer. */
3959			if (ret == 0) {
3960out:
3961				for (index = 0; index < ret; index++)
3962					page_cache_release(pages[index]);
3963				/* just a hole. */
3964				kfree(pages);
3965				return EXT_CONTINUE;
3966			}
3967			index = 0;
3968
3969next_page:
3970			/* Try to find the 1st mapped buffer. */
3971			end = ((__u64)pages[index]->index << PAGE_SHIFT) >>
3972				  blksize_bits;
3973			if (!page_has_buffers(pages[index]))
3974				goto out;
3975			head = page_buffers(pages[index]);
3976			if (!head)
3977				goto out;
3978
3979			index++;
3980			bh = head;
3981			do {
3982				if (end >= newex->ec_block +
3983					newex->ec_len)
3984					/* The buffer is out of
3985					 * the request range.
3986					 */
3987					goto out;
3988
3989				if (buffer_mapped(bh) &&
3990				    end >= newex->ec_block) {
3991					start_index = index - 1;
3992					/* get the 1st mapped buffer. */
3993					goto found_mapped_buffer;
3994				}
3995
3996				bh = bh->b_this_page;
3997				end++;
3998			} while (bh != head);
3999
4000			/* No mapped buffer in the range found in this page,
4001			 * We need to look up next page.
4002			 */
4003			if (index >= ret) {
4004				/* There is no page left, but we need to limit
4005				 * newex->ec_len.
4006				 */
4007				newex->ec_len = end - newex->ec_block;
4008				goto out;
4009			}
4010			goto next_page;
4011		} else {
4012			/*Find contiguous delayed buffers. */
4013			if (ret > 0 && pages[0]->index == last_offset)
4014				head = page_buffers(pages[0]);
4015			bh = head;
4016			index = 1;
4017			start_index = 0;
4018		}
4019
4020found_mapped_buffer:
4021		if (bh != NULL && buffer_delay(bh)) {
4022			/* 1st or contiguous delayed buffer found. */
4023			if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
4024				/*
4025				 * 1st delayed buffer found, record
4026				 * the start of extent.
4027				 */
4028				flags |= FIEMAP_EXTENT_DELALLOC;
4029				newex->ec_block = end;
4030				logical = (__u64)end << blksize_bits;
4031			}
4032			/* Find contiguous delayed buffers. */
4033			do {
4034				if (!buffer_delay(bh))
4035					goto found_delayed_extent;
4036				bh = bh->b_this_page;
4037				end++;
4038			} while (bh != head);
4039
4040			for (; index < ret; index++) {
4041				if (!page_has_buffers(pages[index])) {
4042					bh = NULL;
4043					break;
4044				}
4045				head = page_buffers(pages[index]);
4046				if (!head) {
4047					bh = NULL;
4048					break;
4049				}
4050
4051				if (pages[index]->index !=
4052				    pages[start_index]->index + index
4053				    - start_index) {
4054					/* Blocks are not contiguous. */
4055					bh = NULL;
4056					break;
4057				}
4058				bh = head;
4059				do {
4060					if (!buffer_delay(bh))
4061						/* Delayed-extent ends. */
4062						goto found_delayed_extent;
4063					bh = bh->b_this_page;
4064					end++;
4065				} while (bh != head);
4066			}
4067		} else if (!(flags & FIEMAP_EXTENT_DELALLOC))
4068			/* a hole found. */
4069			goto out;
4070
4071found_delayed_extent:
4072		newex->ec_len = min(end - newex->ec_block,
4073						(ext4_lblk_t)EXT_INIT_MAX_LEN);
4074		if (ret == nr_pages && bh != NULL &&
4075			newex->ec_len < EXT_INIT_MAX_LEN &&
4076			buffer_delay(bh)) {
4077			/* Have not collected an extent and continue. */
4078			for (index = 0; index < ret; index++)
4079				page_cache_release(pages[index]);
4080			goto repeat;
4081		}
4082
4083		for (index = 0; index < ret; index++)
4084			page_cache_release(pages[index]);
4085		kfree(pages);
4086	}
4087
4088	physical = (__u64)newex->ec_start << blksize_bits;
4089	length =   (__u64)newex->ec_len << blksize_bits;
4090
4091	if (ex && ext4_ext_is_uninitialized(ex))
4092		flags |= FIEMAP_EXTENT_UNWRITTEN;
 
 
 
 
 
4093
4094	if (next == EXT_MAX_BLOCKS)
4095		flags |= FIEMAP_EXTENT_LAST;
4096
4097	ret = fiemap_fill_next_extent(fieinfo, logical, physical,
4098					length, flags);
4099	if (ret < 0)
4100		return ret;
4101	if (ret == 1)
4102		return EXT_BREAK;
4103	return EXT_CONTINUE;
4104}
4105
4106/* fiemap flags we can handle specified here */
4107#define EXT4_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4108
4109static int ext4_xattr_fiemap(struct inode *inode,
4110				struct fiemap_extent_info *fieinfo)
4111{
4112	__u64 physical = 0;
4113	__u64 length;
4114	__u32 flags = FIEMAP_EXTENT_LAST;
4115	int blockbits = inode->i_sb->s_blocksize_bits;
4116	int error = 0;
 
4117
4118	/* in-inode? */
4119	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4120		struct ext4_iloc iloc;
4121		int offset;	/* offset of xattr in inode */
4122
4123		error = ext4_get_inode_loc(inode, &iloc);
4124		if (error)
4125			return error;
4126		physical = iloc.bh->b_blocknr << blockbits;
4127		offset = EXT4_GOOD_OLD_INODE_SIZE +
4128				EXT4_I(inode)->i_extra_isize;
4129		physical += offset;
4130		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4131		flags |= FIEMAP_EXTENT_DATA_INLINE;
4132		brelse(iloc.bh);
4133	} else { /* external block */
4134		physical = EXT4_I(inode)->i_file_acl << blockbits;
 
4135		length = inode->i_sb->s_blocksize;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4136	}
4137
4138	if (physical)
4139		error = fiemap_fill_next_extent(fieinfo, 0, physical,
4140						length, flags);
4141	return (error < 0 ? error : 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4142}
4143
4144/*
4145 * ext4_ext_punch_hole
4146 *
4147 * Punches a hole of "length" bytes in a file starting
4148 * at byte "offset"
4149 *
4150 * @inode:  The inode of the file to punch a hole in
4151 * @offset: The starting byte offset of the hole
4152 * @length: The length of the hole
4153 *
4154 * Returns the number of blocks removed or negative on err
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4155 */
4156int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
 
 
 
4157{
4158	struct inode *inode = file->f_path.dentry->d_inode;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4159	struct super_block *sb = inode->i_sb;
4160	struct ext4_ext_cache cache_ex;
4161	ext4_lblk_t first_block, last_block, num_blocks, iblock, max_blocks;
4162	struct address_space *mapping = inode->i_mapping;
4163	struct ext4_map_blocks map;
4164	handle_t *handle;
4165	loff_t first_block_offset, last_block_offset, block_len;
4166	loff_t first_page, last_page, first_page_offset, last_page_offset;
4167	int ret, credits, blocks_released, err = 0;
4168
4169	first_block = (offset + sb->s_blocksize - 1) >>
4170		EXT4_BLOCK_SIZE_BITS(sb);
4171	last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
 
 
 
 
4172
4173	first_block_offset = first_block << EXT4_BLOCK_SIZE_BITS(sb);
4174	last_block_offset = last_block << EXT4_BLOCK_SIZE_BITS(sb);
 
4175
4176	first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
4177	last_page = (offset + length) >> PAGE_CACHE_SHIFT;
4178
4179	first_page_offset = first_page << PAGE_CACHE_SHIFT;
4180	last_page_offset = last_page << PAGE_CACHE_SHIFT;
4181
 
4182	/*
4183	 * Write out all dirty pages to avoid race conditions
4184	 * Then release them.
4185	 */
4186	if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4187		err = filemap_write_and_wait_range(mapping,
4188			first_page_offset == 0 ? 0 : first_page_offset-1,
4189			last_page_offset);
4190
4191			if (err)
4192				return err;
4193	}
4194
4195	/* Now release the pages */
4196	if (last_page_offset > first_page_offset) {
4197		truncate_inode_pages_range(mapping, first_page_offset,
4198					   last_page_offset-1);
4199	}
4200
4201	/* finish any pending end_io work */
4202	ext4_flush_completed_IO(inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4203
4204	credits = ext4_writepage_trans_blocks(inode);
4205	handle = ext4_journal_start(inode, credits);
4206	if (IS_ERR(handle))
4207		return PTR_ERR(handle);
 
 
 
4208
4209	err = ext4_orphan_add(handle, inode);
4210	if (err)
4211		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4212
4213	/*
4214	 * Now we need to zero out the un block aligned data.
4215	 * If the file is smaller than a block, just
4216	 * zero out the middle
4217	 */
4218	if (first_block > last_block)
4219		ext4_block_zero_page_range(handle, mapping, offset, length);
4220	else {
4221		/* zero out the head of the hole before the first block */
4222		block_len  = first_block_offset - offset;
4223		if (block_len > 0)
4224			ext4_block_zero_page_range(handle, mapping,
4225						   offset, block_len);
4226
4227		/* zero out the tail of the hole after the last block */
4228		block_len = offset + length - last_block_offset;
4229		if (block_len > 0) {
4230			ext4_block_zero_page_range(handle, mapping,
4231					last_block_offset, block_len);
4232		}
 
 
4233	}
4234
4235	/* If there are no blocks to remove, return now */
4236	if (first_block >= last_block)
4237		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4238
4239	down_write(&EXT4_I(inode)->i_data_sem);
4240	ext4_ext_invalidate_cache(inode);
4241	ext4_discard_preallocations(inode);
4242
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4243	/*
4244	 * Loop over all the blocks and identify blocks
4245	 * that need to be punched out
4246	 */
4247	iblock = first_block;
4248	blocks_released = 0;
4249	while (iblock < last_block) {
4250		max_blocks = last_block - iblock;
4251		num_blocks = 1;
4252		memset(&map, 0, sizeof(map));
4253		map.m_lblk = iblock;
4254		map.m_len = max_blocks;
4255		ret = ext4_ext_map_blocks(handle, inode, &map,
4256			EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
4257
4258		if (ret > 0) {
4259			blocks_released += ret;
4260			num_blocks = ret;
4261		} else if (ret == 0) {
4262			/*
4263			 * If map blocks could not find the block,
4264			 * then it is in a hole.  If the hole was
4265			 * not already cached, then map blocks should
4266			 * put it in the cache.  So we can get the hole
4267			 * out of the cache
4268			 */
4269			memset(&cache_ex, 0, sizeof(cache_ex));
4270			if ((ext4_ext_check_cache(inode, iblock, &cache_ex)) &&
4271				!cache_ex.ec_start) {
4272
4273				/* The hole is cached */
4274				num_blocks = cache_ex.ec_block +
4275				cache_ex.ec_len - iblock;
4276
4277			} else {
4278				/* The block could not be identified */
4279				err = -EIO;
4280				break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4281			}
4282		} else {
4283			/* Map blocks error */
4284			err = ret;
4285			break;
4286		}
 
 
 
 
4287
4288		if (num_blocks == 0) {
4289			/* This condition should never happen */
4290			ext_debug("Block lookup failed");
4291			err = -EIO;
4292			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4293		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4294
4295		iblock += num_blocks;
 
 
 
4296	}
4297
4298	if (blocks_released > 0) {
4299		ext4_ext_invalidate_cache(inode);
4300		ext4_discard_preallocations(inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4301	}
4302
4303	if (IS_SYNC(inode))
4304		ext4_handle_sync(handle);
4305
4306	up_write(&EXT4_I(inode)->i_data_sem);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4307
4308out:
4309	ext4_orphan_del(handle, inode);
4310	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4311	ext4_mark_inode_dirty(handle, inode);
4312	ext4_journal_stop(handle);
4313	return err;
4314}
4315int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4316		__u64 start, __u64 len)
 
 
 
 
 
 
 
 
4317{
4318	ext4_lblk_t start_blk;
4319	int error = 0;
 
4320
4321	/* fallback to generic here if not in extents fmt */
4322	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4323		return generic_block_fiemap(inode, fieinfo, start, len,
4324			ext4_get_block);
 
 
 
 
4325
4326	if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4327		return -EBADR;
 
 
 
 
 
 
 
 
4328
4329	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4330		error = ext4_xattr_fiemap(inode, fieinfo);
4331	} else {
4332		ext4_lblk_t len_blks;
4333		__u64 last_blk;
4334
4335		start_blk = start >> inode->i_sb->s_blocksize_bits;
4336		last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4337		if (last_blk >= EXT_MAX_BLOCKS)
4338			last_blk = EXT_MAX_BLOCKS-1;
4339		len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4340
4341		/*
4342		 * Walk the extent tree gathering extent information.
4343		 * ext4_ext_fiemap_cb will push extents back to user.
4344		 */
4345		error = ext4_ext_walk_space(inode, start_blk, len_blks,
4346					  ext4_ext_fiemap_cb, fieinfo);
 
 
 
 
 
 
 
 
 
4347	}
 
 
 
 
 
 
 
 
 
 
 
 
 
4348
4349	return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4350}