brintos / linux-shallow public Read only

1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com4 * Written by Alex Tomas <alex@clusterfs.com>5 *6 * Architecture independence:7 *   Copyright (c) 2005, Bull S.A.8 *   Written by Pierre Peiffer <pierre.peiffer@bull.net>9 */10 11/*12 * Extents support for EXT413 *14 * TODO:15 *   - ext4*_error() should be used in some situations16 *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate17 *   - smart tree reduction18 */19 20#include <linux/fs.h>21#include <linux/time.h>22#include <linux/jbd2.h>23#include <linux/highuid.h>24#include <linux/pagemap.h>25#include <linux/quotaops.h>26#include <linux/string.h>27#include <linux/slab.h>28#include <linux/uaccess.h>29#include <linux/fiemap.h>30#include <linux/iomap.h>31#include <linux/sched/mm.h>32#include "ext4_jbd2.h"33#include "ext4_extents.h"34#include "xattr.h"35 36#include <trace/events/ext4.h>37 38/*39 * used by extent splitting.40 */41#define EXT4_EXT_MAY_ZEROOUT	0x1  /* safe to zeroout if split fails \42					due to ENOSPC */43#define EXT4_EXT_MARK_UNWRIT1	0x2  /* mark first half unwritten */44#define EXT4_EXT_MARK_UNWRIT2	0x4  /* mark second half unwritten */45 46#define EXT4_EXT_DATA_VALID1	0x8  /* first half contains valid data */47#define EXT4_EXT_DATA_VALID2	0x10 /* second half contains valid data */48 49static __le32 ext4_extent_block_csum(struct inode *inode,50				     struct ext4_extent_header *eh)51{52	struct ext4_inode_info *ei = EXT4_I(inode);53	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);54	__u32 csum;55 56	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,57			   EXT4_EXTENT_TAIL_OFFSET(eh));58	return cpu_to_le32(csum);59}60 61static int ext4_extent_block_csum_verify(struct inode *inode,62					 struct ext4_extent_header *eh)63{64	struct ext4_extent_tail *et;65 66	if (!ext4_has_metadata_csum(inode->i_sb))67		return 1;68 69	et = find_ext4_extent_tail(eh);70	if (et->et_checksum != ext4_extent_block_csum(inode, eh))71		return 0;72	return 1;73}74 75static void ext4_extent_block_csum_set(struct inode *inode,76				       struct ext4_extent_header *eh)77{78	struct ext4_extent_tail *et;79 80	if (!ext4_has_metadata_csum(inode->i_sb))81		return;82 83	et = find_ext4_extent_tail(eh);84	et->et_checksum = ext4_extent_block_csum(inode, eh);85}86 87static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,88						  struct inode *inode,89						  struct ext4_ext_path *path,90						  ext4_lblk_t split,91						  int split_flag, int flags);92 93static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)94{95	/*96	 * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this97	 * moment, get_block can be called only for blocks inside i_size since98	 * page cache has been already dropped and writes are blocked by99	 * i_rwsem. So we can safely drop the i_data_sem here.100	 */101	BUG_ON(EXT4_JOURNAL(inode) == NULL);102	ext4_discard_preallocations(inode);103	up_write(&EXT4_I(inode)->i_data_sem);104	*dropped = 1;105	return 0;106}107 108static inline void ext4_ext_path_brelse(struct ext4_ext_path *path)109{110	brelse(path->p_bh);111	path->p_bh = NULL;112}113 114static void ext4_ext_drop_refs(struct ext4_ext_path *path)115{116	int depth, i;117 118	if (IS_ERR_OR_NULL(path))119		return;120	depth = path->p_depth;121	for (i = 0; i <= depth; i++, path++)122		ext4_ext_path_brelse(path);123}124 125void ext4_free_ext_path(struct ext4_ext_path *path)126{127	if (IS_ERR_OR_NULL(path))128		return;129	ext4_ext_drop_refs(path);130	kfree(path);131}132 133/*134 * Make sure 'handle' has at least 'check_cred' credits. If not, restart135 * transaction with 'restart_cred' credits. The function drops i_data_sem136 * when restarting transaction and gets it after transaction is restarted.137 *138 * The function returns 0 on success, 1 if transaction had to be restarted,139 * and < 0 in case of fatal error.140 */141int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,142				int check_cred, int restart_cred,143				int revoke_cred)144{145	int ret;146	int dropped = 0;147 148	ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,149		revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));150	if (dropped)151		down_write(&EXT4_I(inode)->i_data_sem);152	return ret;153}154 155/*156 * could return:157 *  - EROFS158 *  - ENOMEM159 */160static int ext4_ext_get_access(handle_t *handle, struct inode *inode,161				struct ext4_ext_path *path)162{163	int err = 0;164 165	if (path->p_bh) {166		/* path points to block */167		BUFFER_TRACE(path->p_bh, "get_write_access");168		err = ext4_journal_get_write_access(handle, inode->i_sb,169						    path->p_bh, EXT4_JTR_NONE);170		/*171		 * The extent buffer's verified bit will be set again in172		 * __ext4_ext_dirty(). We could leave an inconsistent173		 * buffer if the extents updating procudure break off du174		 * to some error happens, force to check it again.175		 */176		if (!err)177			clear_buffer_verified(path->p_bh);178	}179	/* path points to leaf/index in inode body */180	/* we use in-core data, no need to protect them */181	return err;182}183 184/*185 * could return:186 *  - EROFS187 *  - ENOMEM188 *  - EIO189 */190static int __ext4_ext_dirty(const char *where, unsigned int line,191			    handle_t *handle, struct inode *inode,192			    struct ext4_ext_path *path)193{194	int err;195 196	WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));197	if (path->p_bh) {198		ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));199		/* path points to block */200		err = __ext4_handle_dirty_metadata(where, line, handle,201						   inode, path->p_bh);202		/* Extents updating done, re-set verified flag */203		if (!err)204			set_buffer_verified(path->p_bh);205	} else {206		/* path points to leaf/index in inode body */207		err = ext4_mark_inode_dirty(handle, inode);208	}209	return err;210}211 212#define ext4_ext_dirty(handle, inode, path) \213		__ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))214 215static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,216			      struct ext4_ext_path *path,217			      ext4_lblk_t block)218{219	if (path) {220		int depth = path->p_depth;221		struct ext4_extent *ex;222 223		/*224		 * Try to predict block placement assuming that we are225		 * filling in a file which will eventually be226		 * non-sparse --- i.e., in the case of libbfd writing227		 * an ELF object sections out-of-order but in a way228		 * the eventually results in a contiguous object or229		 * executable file, or some database extending a table230		 * space file.  However, this is actually somewhat231		 * non-ideal if we are writing a sparse file such as232		 * qemu or KVM writing a raw image file that is going233		 * to stay fairly sparse, since it will end up234		 * fragmenting the file system's free space.  Maybe we235		 * should have some hueristics or some way to allow236		 * userspace to pass a hint to file system,237		 * especially if the latter case turns out to be238		 * common.239		 */240		ex = path[depth].p_ext;241		if (ex) {242			ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);243			ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);244 245			if (block > ext_block)246				return ext_pblk + (block - ext_block);247			else248				return ext_pblk - (ext_block - block);249		}250 251		/* it looks like index is empty;252		 * try to find starting block from index itself */253		if (path[depth].p_bh)254			return path[depth].p_bh->b_blocknr;255	}256 257	/* OK. use inode's group */258	return ext4_inode_to_goal_block(inode);259}260 261/*262 * Allocation for a meta data block263 */264static ext4_fsblk_t265ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,266			struct ext4_ext_path *path,267			struct ext4_extent *ex, int *err, unsigned int flags)268{269	ext4_fsblk_t goal, newblock;270 271	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));272	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,273					NULL, err);274	return newblock;275}276 277static inline int ext4_ext_space_block(struct inode *inode, int check)278{279	int size;280 281	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))282			/ sizeof(struct ext4_extent);283#ifdef AGGRESSIVE_TEST284	if (!check && size > 6)285		size = 6;286#endif287	return size;288}289 290static inline int ext4_ext_space_block_idx(struct inode *inode, int check)291{292	int size;293 294	size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))295			/ sizeof(struct ext4_extent_idx);296#ifdef AGGRESSIVE_TEST297	if (!check && size > 5)298		size = 5;299#endif300	return size;301}302 303static inline int ext4_ext_space_root(struct inode *inode, int check)304{305	int size;306 307	size = sizeof(EXT4_I(inode)->i_data);308	size -= sizeof(struct ext4_extent_header);309	size /= sizeof(struct ext4_extent);310#ifdef AGGRESSIVE_TEST311	if (!check && size > 3)312		size = 3;313#endif314	return size;315}316 317static inline int ext4_ext_space_root_idx(struct inode *inode, int check)318{319	int size;320 321	size = sizeof(EXT4_I(inode)->i_data);322	size -= sizeof(struct ext4_extent_header);323	size /= sizeof(struct ext4_extent_idx);324#ifdef AGGRESSIVE_TEST325	if (!check && size > 4)326		size = 4;327#endif328	return size;329}330 331static inline struct ext4_ext_path *332ext4_force_split_extent_at(handle_t *handle, struct inode *inode,333			   struct ext4_ext_path *path, ext4_lblk_t lblk,334			   int nofail)335{336	int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);337	int flags = EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO;338 339	if (nofail)340		flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL | EXT4_EX_NOFAIL;341 342	return ext4_split_extent_at(handle, inode, path, lblk, unwritten ?343			EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,344			flags);345}346 347static int348ext4_ext_max_entries(struct inode *inode, int depth)349{350	int max;351 352	if (depth == ext_depth(inode)) {353		if (depth == 0)354			max = ext4_ext_space_root(inode, 1);355		else356			max = ext4_ext_space_root_idx(inode, 1);357	} else {358		if (depth == 0)359			max = ext4_ext_space_block(inode, 1);360		else361			max = ext4_ext_space_block_idx(inode, 1);362	}363 364	return max;365}366 367static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)368{369	ext4_fsblk_t block = ext4_ext_pblock(ext);370	int len = ext4_ext_get_actual_len(ext);371	ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);372 373	/*374	 * We allow neither:375	 *  - zero length376	 *  - overflow/wrap-around377	 */378	if (lblock + len <= lblock)379		return 0;380	return ext4_inode_block_valid(inode, block, len);381}382 383static int ext4_valid_extent_idx(struct inode *inode,384				struct ext4_extent_idx *ext_idx)385{386	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);387 388	return ext4_inode_block_valid(inode, block, 1);389}390 391static int ext4_valid_extent_entries(struct inode *inode,392				     struct ext4_extent_header *eh,393				     ext4_lblk_t lblk, ext4_fsblk_t *pblk,394				     int depth)395{396	unsigned short entries;397	ext4_lblk_t lblock = 0;398	ext4_lblk_t cur = 0;399 400	if (eh->eh_entries == 0)401		return 1;402 403	entries = le16_to_cpu(eh->eh_entries);404 405	if (depth == 0) {406		/* leaf entries */407		struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);408 409		/*410		 * The logical block in the first entry should equal to411		 * the number in the index block.412		 */413		if (depth != ext_depth(inode) &&414		    lblk != le32_to_cpu(ext->ee_block))415			return 0;416		while (entries) {417			if (!ext4_valid_extent(inode, ext))418				return 0;419 420			/* Check for overlapping extents */421			lblock = le32_to_cpu(ext->ee_block);422			if (lblock < cur) {423				*pblk = ext4_ext_pblock(ext);424				return 0;425			}426			cur = lblock + ext4_ext_get_actual_len(ext);427			ext++;428			entries--;429		}430	} else {431		struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);432 433		/*434		 * The logical block in the first entry should equal to435		 * the number in the parent index block.436		 */437		if (depth != ext_depth(inode) &&438		    lblk != le32_to_cpu(ext_idx->ei_block))439			return 0;440		while (entries) {441			if (!ext4_valid_extent_idx(inode, ext_idx))442				return 0;443 444			/* Check for overlapping index extents */445			lblock = le32_to_cpu(ext_idx->ei_block);446			if (lblock < cur) {447				*pblk = ext4_idx_pblock(ext_idx);448				return 0;449			}450			ext_idx++;451			entries--;452			cur = lblock + 1;453		}454	}455	return 1;456}457 458static int __ext4_ext_check(const char *function, unsigned int line,459			    struct inode *inode, struct ext4_extent_header *eh,460			    int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)461{462	const char *error_msg;463	int max = 0, err = -EFSCORRUPTED;464 465	if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {466		error_msg = "invalid magic";467		goto corrupted;468	}469	if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {470		error_msg = "unexpected eh_depth";471		goto corrupted;472	}473	if (unlikely(eh->eh_max == 0)) {474		error_msg = "invalid eh_max";475		goto corrupted;476	}477	max = ext4_ext_max_entries(inode, depth);478	if (unlikely(le16_to_cpu(eh->eh_max) > max)) {479		error_msg = "too large eh_max";480		goto corrupted;481	}482	if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {483		error_msg = "invalid eh_entries";484		goto corrupted;485	}486	if (unlikely((eh->eh_entries == 0) && (depth > 0))) {487		error_msg = "eh_entries is 0 but eh_depth is > 0";488		goto corrupted;489	}490	if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {491		error_msg = "invalid extent entries";492		goto corrupted;493	}494	if (unlikely(depth > 32)) {495		error_msg = "too large eh_depth";496		goto corrupted;497	}498	/* Verify checksum on non-root extent tree nodes */499	if (ext_depth(inode) != depth &&500	    !ext4_extent_block_csum_verify(inode, eh)) {501		error_msg = "extent tree corrupted";502		err = -EFSBADCRC;503		goto corrupted;504	}505	return 0;506 507corrupted:508	ext4_error_inode_err(inode, function, line, 0, -err,509			     "pblk %llu bad header/extent: %s - magic %x, "510			     "entries %u, max %u(%u), depth %u(%u)",511			     (unsigned long long) pblk, error_msg,512			     le16_to_cpu(eh->eh_magic),513			     le16_to_cpu(eh->eh_entries),514			     le16_to_cpu(eh->eh_max),515			     max, le16_to_cpu(eh->eh_depth), depth);516	return err;517}518 519#define ext4_ext_check(inode, eh, depth, pblk)			\520	__ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)521 522int ext4_ext_check_inode(struct inode *inode)523{524	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);525}526 527static void ext4_cache_extents(struct inode *inode,528			       struct ext4_extent_header *eh)529{530	struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);531	ext4_lblk_t prev = 0;532	int i;533 534	for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {535		unsigned int status = EXTENT_STATUS_WRITTEN;536		ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);537		int len = ext4_ext_get_actual_len(ex);538 539		if (prev && (prev != lblk))540			ext4_es_cache_extent(inode, prev, lblk - prev, ~0,541					     EXTENT_STATUS_HOLE);542 543		if (ext4_ext_is_unwritten(ex))544			status = EXTENT_STATUS_UNWRITTEN;545		ext4_es_cache_extent(inode, lblk, len,546				     ext4_ext_pblock(ex), status);547		prev = lblk + len;548	}549}550 551static struct buffer_head *552__read_extent_tree_block(const char *function, unsigned int line,553			 struct inode *inode, struct ext4_extent_idx *idx,554			 int depth, int flags)555{556	struct buffer_head		*bh;557	int				err;558	gfp_t				gfp_flags = __GFP_MOVABLE | GFP_NOFS;559	ext4_fsblk_t			pblk;560 561	if (flags & EXT4_EX_NOFAIL)562		gfp_flags |= __GFP_NOFAIL;563 564	pblk = ext4_idx_pblock(idx);565	bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);566	if (unlikely(!bh))567		return ERR_PTR(-ENOMEM);568 569	if (!bh_uptodate_or_lock(bh)) {570		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);571		err = ext4_read_bh(bh, 0, NULL);572		if (err < 0)573			goto errout;574	}575	if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))576		return bh;577	err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),578			       depth, pblk, le32_to_cpu(idx->ei_block));579	if (err)580		goto errout;581	set_buffer_verified(bh);582	/*583	 * If this is a leaf block, cache all of its entries584	 */585	if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {586		struct ext4_extent_header *eh = ext_block_hdr(bh);587		ext4_cache_extents(inode, eh);588	}589	return bh;590errout:591	put_bh(bh);592	return ERR_PTR(err);593 594}595 596#define read_extent_tree_block(inode, idx, depth, flags)		\597	__read_extent_tree_block(__func__, __LINE__, (inode), (idx),	\598				 (depth), (flags))599 600/*601 * This function is called to cache a file's extent information in the602 * extent status tree603 */604int ext4_ext_precache(struct inode *inode)605{606	struct ext4_inode_info *ei = EXT4_I(inode);607	struct ext4_ext_path *path = NULL;608	struct buffer_head *bh;609	int i = 0, depth, ret = 0;610 611	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))612		return 0;	/* not an extent-mapped inode */613 614	down_read(&ei->i_data_sem);615	depth = ext_depth(inode);616 617	/* Don't cache anything if there are no external extent blocks */618	if (!depth) {619		up_read(&ei->i_data_sem);620		return ret;621	}622 623	path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),624		       GFP_NOFS);625	if (path == NULL) {626		up_read(&ei->i_data_sem);627		return -ENOMEM;628	}629 630	path[0].p_hdr = ext_inode_hdr(inode);631	ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);632	if (ret)633		goto out;634	path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);635	while (i >= 0) {636		/*637		 * If this is a leaf block or we've reached the end of638		 * the index block, go up639		 */640		if ((i == depth) ||641		    path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {642			ext4_ext_path_brelse(path + i);643			i--;644			continue;645		}646		bh = read_extent_tree_block(inode, path[i].p_idx++,647					    depth - i - 1,648					    EXT4_EX_FORCE_CACHE);649		if (IS_ERR(bh)) {650			ret = PTR_ERR(bh);651			break;652		}653		i++;654		path[i].p_bh = bh;655		path[i].p_hdr = ext_block_hdr(bh);656		path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);657	}658	ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);659out:660	up_read(&ei->i_data_sem);661	ext4_free_ext_path(path);662	return ret;663}664 665#ifdef EXT_DEBUG666static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)667{668	int k, l = path->p_depth;669 670	ext_debug(inode, "path:");671	for (k = 0; k <= l; k++, path++) {672		if (path->p_idx) {673			ext_debug(inode, "  %d->%llu",674				  le32_to_cpu(path->p_idx->ei_block),675				  ext4_idx_pblock(path->p_idx));676		} else if (path->p_ext) {677			ext_debug(inode, "  %d:[%d]%d:%llu ",678				  le32_to_cpu(path->p_ext->ee_block),679				  ext4_ext_is_unwritten(path->p_ext),680				  ext4_ext_get_actual_len(path->p_ext),681				  ext4_ext_pblock(path->p_ext));682		} else683			ext_debug(inode, "  []");684	}685	ext_debug(inode, "\n");686}687 688static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)689{690	int depth = ext_depth(inode);691	struct ext4_extent_header *eh;692	struct ext4_extent *ex;693	int i;694 695	if (IS_ERR_OR_NULL(path))696		return;697 698	eh = path[depth].p_hdr;699	ex = EXT_FIRST_EXTENT(eh);700 701	ext_debug(inode, "Displaying leaf extents\n");702 703	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {704		ext_debug(inode, "%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),705			  ext4_ext_is_unwritten(ex),706			  ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));707	}708	ext_debug(inode, "\n");709}710 711static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,712			ext4_fsblk_t newblock, int level)713{714	int depth = ext_depth(inode);715	struct ext4_extent *ex;716 717	if (depth != level) {718		struct ext4_extent_idx *idx;719		idx = path[level].p_idx;720		while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {721			ext_debug(inode, "%d: move %d:%llu in new index %llu\n",722				  level, le32_to_cpu(idx->ei_block),723				  ext4_idx_pblock(idx), newblock);724			idx++;725		}726 727		return;728	}729 730	ex = path[depth].p_ext;731	while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {732		ext_debug(inode, "move %d:%llu:[%d]%d in new leaf %llu\n",733				le32_to_cpu(ex->ee_block),734				ext4_ext_pblock(ex),735				ext4_ext_is_unwritten(ex),736				ext4_ext_get_actual_len(ex),737				newblock);738		ex++;739	}740}741 742#else743#define ext4_ext_show_path(inode, path)744#define ext4_ext_show_leaf(inode, path)745#define ext4_ext_show_move(inode, path, newblock, level)746#endif747 748/*749 * ext4_ext_binsearch_idx:750 * binary search for the closest index of the given block751 * the header must be checked before calling this752 */753static void754ext4_ext_binsearch_idx(struct inode *inode,755			struct ext4_ext_path *path, ext4_lblk_t block)756{757	struct ext4_extent_header *eh = path->p_hdr;758	struct ext4_extent_idx *r, *l, *m;759 760 761	ext_debug(inode, "binsearch for %u(idx):  ", block);762 763	l = EXT_FIRST_INDEX(eh) + 1;764	r = EXT_LAST_INDEX(eh);765	while (l <= r) {766		m = l + (r - l) / 2;767		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,768			  le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block),769			  r, le32_to_cpu(r->ei_block));770 771		if (block < le32_to_cpu(m->ei_block))772			r = m - 1;773		else774			l = m + 1;775	}776 777	path->p_idx = l - 1;778	ext_debug(inode, "  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),779		  ext4_idx_pblock(path->p_idx));780 781#ifdef CHECK_BINSEARCH782	{783		struct ext4_extent_idx *chix, *ix;784		int k;785 786		chix = ix = EXT_FIRST_INDEX(eh);787		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {788			if (k != 0 && le32_to_cpu(ix->ei_block) <=789			    le32_to_cpu(ix[-1].ei_block)) {790				printk(KERN_DEBUG "k=%d, ix=0x%p, "791				       "first=0x%p\n", k,792				       ix, EXT_FIRST_INDEX(eh));793				printk(KERN_DEBUG "%u <= %u\n",794				       le32_to_cpu(ix->ei_block),795				       le32_to_cpu(ix[-1].ei_block));796			}797			BUG_ON(k && le32_to_cpu(ix->ei_block)798					   <= le32_to_cpu(ix[-1].ei_block));799			if (block < le32_to_cpu(ix->ei_block))800				break;801			chix = ix;802		}803		BUG_ON(chix != path->p_idx);804	}805#endif806 807}808 809/*810 * ext4_ext_binsearch:811 * binary search for closest extent of the given block812 * the header must be checked before calling this813 */814static void815ext4_ext_binsearch(struct inode *inode,816		struct ext4_ext_path *path, ext4_lblk_t block)817{818	struct ext4_extent_header *eh = path->p_hdr;819	struct ext4_extent *r, *l, *m;820 821	if (eh->eh_entries == 0) {822		/*823		 * this leaf is empty:824		 * we get such a leaf in split/add case825		 */826		return;827	}828 829	ext_debug(inode, "binsearch for %u:  ", block);830 831	l = EXT_FIRST_EXTENT(eh) + 1;832	r = EXT_LAST_EXTENT(eh);833 834	while (l <= r) {835		m = l + (r - l) / 2;836		ext_debug(inode, "%p(%u):%p(%u):%p(%u) ", l,837			  le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block),838			  r, le32_to_cpu(r->ee_block));839 840		if (block < le32_to_cpu(m->ee_block))841			r = m - 1;842		else843			l = m + 1;844	}845 846	path->p_ext = l - 1;847	ext_debug(inode, "  -> %d:%llu:[%d]%d ",848			le32_to_cpu(path->p_ext->ee_block),849			ext4_ext_pblock(path->p_ext),850			ext4_ext_is_unwritten(path->p_ext),851			ext4_ext_get_actual_len(path->p_ext));852 853#ifdef CHECK_BINSEARCH854	{855		struct ext4_extent *chex, *ex;856		int k;857 858		chex = ex = EXT_FIRST_EXTENT(eh);859		for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {860			BUG_ON(k && le32_to_cpu(ex->ee_block)861					  <= le32_to_cpu(ex[-1].ee_block));862			if (block < le32_to_cpu(ex->ee_block))863				break;864			chex = ex;865		}866		BUG_ON(chex != path->p_ext);867	}868#endif869 870}871 872void ext4_ext_tree_init(handle_t *handle, struct inode *inode)873{874	struct ext4_extent_header *eh;875 876	eh = ext_inode_hdr(inode);877	eh->eh_depth = 0;878	eh->eh_entries = 0;879	eh->eh_magic = EXT4_EXT_MAGIC;880	eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));881	eh->eh_generation = 0;882	ext4_mark_inode_dirty(handle, inode);883}884 885struct ext4_ext_path *886ext4_find_extent(struct inode *inode, ext4_lblk_t block,887		 struct ext4_ext_path *path, int flags)888{889	struct ext4_extent_header *eh;890	struct buffer_head *bh;891	short int depth, i, ppos = 0;892	int ret;893	gfp_t gfp_flags = GFP_NOFS;894 895	if (flags & EXT4_EX_NOFAIL)896		gfp_flags |= __GFP_NOFAIL;897 898	eh = ext_inode_hdr(inode);899	depth = ext_depth(inode);900	if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {901		EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",902				 depth);903		ret = -EFSCORRUPTED;904		goto err;905	}906 907	if (path) {908		ext4_ext_drop_refs(path);909		if (depth > path[0].p_maxdepth) {910			kfree(path);911			path = NULL;912		}913	}914	if (!path) {915		/* account possible depth increase */916		path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),917				gfp_flags);918		if (unlikely(!path))919			return ERR_PTR(-ENOMEM);920		path[0].p_maxdepth = depth + 1;921	}922	path[0].p_hdr = eh;923	path[0].p_bh = NULL;924 925	i = depth;926	if (!(flags & EXT4_EX_NOCACHE) && depth == 0)927		ext4_cache_extents(inode, eh);928	/* walk through the tree */929	while (i) {930		ext_debug(inode, "depth %d: num %d, max %d\n",931			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));932 933		ext4_ext_binsearch_idx(inode, path + ppos, block);934		path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);935		path[ppos].p_depth = i;936		path[ppos].p_ext = NULL;937 938		bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);939		if (IS_ERR(bh)) {940			ret = PTR_ERR(bh);941			goto err;942		}943 944		eh = ext_block_hdr(bh);945		ppos++;946		path[ppos].p_bh = bh;947		path[ppos].p_hdr = eh;948	}949 950	path[ppos].p_depth = i;951	path[ppos].p_ext = NULL;952	path[ppos].p_idx = NULL;953 954	/* find extent */955	ext4_ext_binsearch(inode, path + ppos, block);956	/* if not an empty leaf */957	if (path[ppos].p_ext)958		path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);959 960	ext4_ext_show_path(inode, path);961 962	return path;963 964err:965	ext4_free_ext_path(path);966	return ERR_PTR(ret);967}968 969/*970 * ext4_ext_insert_index:971 * insert new index [@logical;@ptr] into the block at @curp;972 * check where to insert: before @curp or after @curp973 */974static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,975				 struct ext4_ext_path *curp,976				 int logical, ext4_fsblk_t ptr)977{978	struct ext4_extent_idx *ix;979	int len, err;980 981	err = ext4_ext_get_access(handle, inode, curp);982	if (err)983		return err;984 985	if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {986		EXT4_ERROR_INODE(inode,987				 "logical %d == ei_block %d!",988				 logical, le32_to_cpu(curp->p_idx->ei_block));989		return -EFSCORRUPTED;990	}991 992	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)993			     >= le16_to_cpu(curp->p_hdr->eh_max))) {994		EXT4_ERROR_INODE(inode,995				 "eh_entries %d >= eh_max %d!",996				 le16_to_cpu(curp->p_hdr->eh_entries),997				 le16_to_cpu(curp->p_hdr->eh_max));998		return -EFSCORRUPTED;999	}1000 1001	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {1002		/* insert after */1003		ext_debug(inode, "insert new index %d after: %llu\n",1004			  logical, ptr);1005		ix = curp->p_idx + 1;1006	} else {1007		/* insert before */1008		ext_debug(inode, "insert new index %d before: %llu\n",1009			  logical, ptr);1010		ix = curp->p_idx;1011	}1012 1013	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {1014		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");1015		return -EFSCORRUPTED;1016	}1017 1018	len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;1019	BUG_ON(len < 0);1020	if (len > 0) {1021		ext_debug(inode, "insert new index %d: "1022				"move %d indices from 0x%p to 0x%p\n",1023				logical, len, ix, ix + 1);1024		memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));1025	}1026 1027	ix->ei_block = cpu_to_le32(logical);1028	ext4_idx_store_pblock(ix, ptr);1029	le16_add_cpu(&curp->p_hdr->eh_entries, 1);1030 1031	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {1032		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");1033		return -EFSCORRUPTED;1034	}1035 1036	err = ext4_ext_dirty(handle, inode, curp);1037	ext4_std_error(inode->i_sb, err);1038 1039	return err;1040}1041 1042/*1043 * ext4_ext_split:1044 * inserts new subtree into the path, using free index entry1045 * at depth @at:1046 * - allocates all needed blocks (new leaf and all intermediate index blocks)1047 * - makes decision where to split1048 * - moves remaining extents and index entries (right to the split point)1049 *   into the newly allocated blocks1050 * - initializes subtree1051 */1052static int ext4_ext_split(handle_t *handle, struct inode *inode,1053			  unsigned int flags,1054			  struct ext4_ext_path *path,1055			  struct ext4_extent *newext, int at)1056{1057	struct buffer_head *bh = NULL;1058	int depth = ext_depth(inode);1059	struct ext4_extent_header *neh;1060	struct ext4_extent_idx *fidx;1061	int i = at, k, m, a;1062	ext4_fsblk_t newblock, oldblock;1063	__le32 border;1064	ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */1065	gfp_t gfp_flags = GFP_NOFS;1066	int err = 0;1067	size_t ext_size = 0;1068 1069	if (flags & EXT4_EX_NOFAIL)1070		gfp_flags |= __GFP_NOFAIL;1071 1072	/* make decision: where to split? */1073	/* FIXME: now decision is simplest: at current extent */1074 1075	/* if current leaf will be split, then we should use1076	 * border from split point */1077	if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {1078		EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");1079		return -EFSCORRUPTED;1080	}1081	if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {1082		border = path[depth].p_ext[1].ee_block;1083		ext_debug(inode, "leaf will be split."1084				" next leaf starts at %d\n",1085				  le32_to_cpu(border));1086	} else {1087		border = newext->ee_block;1088		ext_debug(inode, "leaf will be added."1089				" next leaf starts at %d\n",1090				le32_to_cpu(border));1091	}1092 1093	/*1094	 * If error occurs, then we break processing1095	 * and mark filesystem read-only. index won't1096	 * be inserted and tree will be in consistent1097	 * state. Next mount will repair buffers too.1098	 */1099 1100	/*1101	 * Get array to track all allocated blocks.1102	 * We need this to handle errors and free blocks1103	 * upon them.1104	 */1105	ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), gfp_flags);1106	if (!ablocks)1107		return -ENOMEM;1108 1109	/* allocate all needed blocks */1110	ext_debug(inode, "allocate %d blocks for indexes/leaf\n", depth - at);1111	for (a = 0; a < depth - at; a++) {1112		newblock = ext4_ext_new_meta_block(handle, inode, path,1113						   newext, &err, flags);1114		if (newblock == 0)1115			goto cleanup;1116		ablocks[a] = newblock;1117	}1118 1119	/* initialize new leaf */1120	newblock = ablocks[--a];1121	if (unlikely(newblock == 0)) {1122		EXT4_ERROR_INODE(inode, "newblock == 0!");1123		err = -EFSCORRUPTED;1124		goto cleanup;1125	}1126	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);1127	if (unlikely(!bh)) {1128		err = -ENOMEM;1129		goto cleanup;1130	}1131	lock_buffer(bh);1132 1133	err = ext4_journal_get_create_access(handle, inode->i_sb, bh,1134					     EXT4_JTR_NONE);1135	if (err)1136		goto cleanup;1137 1138	neh = ext_block_hdr(bh);1139	neh->eh_entries = 0;1140	neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));1141	neh->eh_magic = EXT4_EXT_MAGIC;1142	neh->eh_depth = 0;1143	neh->eh_generation = 0;1144 1145	/* move remainder of path[depth] to the new leaf */1146	if (unlikely(path[depth].p_hdr->eh_entries !=1147		     path[depth].p_hdr->eh_max)) {1148		EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",1149				 path[depth].p_hdr->eh_entries,1150				 path[depth].p_hdr->eh_max);1151		err = -EFSCORRUPTED;1152		goto cleanup;1153	}1154	/* start copy from next extent */1155	m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;1156	ext4_ext_show_move(inode, path, newblock, depth);1157	if (m) {1158		struct ext4_extent *ex;1159		ex = EXT_FIRST_EXTENT(neh);1160		memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);1161		le16_add_cpu(&neh->eh_entries, m);1162	}1163 1164	/* zero out unused area in the extent block */1165	ext_size = sizeof(struct ext4_extent_header) +1166		sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);1167	memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);1168	ext4_extent_block_csum_set(inode, neh);1169	set_buffer_uptodate(bh);1170	unlock_buffer(bh);1171 1172	err = ext4_handle_dirty_metadata(handle, inode, bh);1173	if (err)1174		goto cleanup;1175	brelse(bh);1176	bh = NULL;1177 1178	/* correct old leaf */1179	if (m) {1180		err = ext4_ext_get_access(handle, inode, path + depth);1181		if (err)1182			goto cleanup;1183		le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);1184		err = ext4_ext_dirty(handle, inode, path + depth);1185		if (err)1186			goto cleanup;1187 1188	}1189 1190	/* create intermediate indexes */1191	k = depth - at - 1;1192	if (unlikely(k < 0)) {1193		EXT4_ERROR_INODE(inode, "k %d < 0!", k);1194		err = -EFSCORRUPTED;1195		goto cleanup;1196	}1197	if (k)1198		ext_debug(inode, "create %d intermediate indices\n", k);1199	/* insert new index into current index block */1200	/* current depth stored in i var */1201	i = depth - 1;1202	while (k--) {1203		oldblock = newblock;1204		newblock = ablocks[--a];1205		bh = sb_getblk(inode->i_sb, newblock);1206		if (unlikely(!bh)) {1207			err = -ENOMEM;1208			goto cleanup;1209		}1210		lock_buffer(bh);1211 1212		err = ext4_journal_get_create_access(handle, inode->i_sb, bh,1213						     EXT4_JTR_NONE);1214		if (err)1215			goto cleanup;1216 1217		neh = ext_block_hdr(bh);1218		neh->eh_entries = cpu_to_le16(1);1219		neh->eh_magic = EXT4_EXT_MAGIC;1220		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));1221		neh->eh_depth = cpu_to_le16(depth - i);1222		neh->eh_generation = 0;1223		fidx = EXT_FIRST_INDEX(neh);1224		fidx->ei_block = border;1225		ext4_idx_store_pblock(fidx, oldblock);1226 1227		ext_debug(inode, "int.index at %d (block %llu): %u -> %llu\n",1228				i, newblock, le32_to_cpu(border), oldblock);1229 1230		/* move remainder of path[i] to the new index block */1231		if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=1232					EXT_LAST_INDEX(path[i].p_hdr))) {1233			EXT4_ERROR_INODE(inode,1234					 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",1235					 le32_to_cpu(path[i].p_ext->ee_block));1236			err = -EFSCORRUPTED;1237			goto cleanup;1238		}1239		/* start copy indexes */1240		m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;1241		ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,1242				EXT_MAX_INDEX(path[i].p_hdr));1243		ext4_ext_show_move(inode, path, newblock, i);1244		if (m) {1245			memmove(++fidx, path[i].p_idx,1246				sizeof(struct ext4_extent_idx) * m);1247			le16_add_cpu(&neh->eh_entries, m);1248		}1249		/* zero out unused area in the extent block */1250		ext_size = sizeof(struct ext4_extent_header) +1251		   (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));1252		memset(bh->b_data + ext_size, 0,1253			inode->i_sb->s_blocksize - ext_size);1254		ext4_extent_block_csum_set(inode, neh);1255		set_buffer_uptodate(bh);1256		unlock_buffer(bh);1257 1258		err = ext4_handle_dirty_metadata(handle, inode, bh);1259		if (err)1260			goto cleanup;1261		brelse(bh);1262		bh = NULL;1263 1264		/* correct old index */1265		if (m) {1266			err = ext4_ext_get_access(handle, inode, path + i);1267			if (err)1268				goto cleanup;1269			le16_add_cpu(&path[i].p_hdr->eh_entries, -m);1270			err = ext4_ext_dirty(handle, inode, path + i);1271			if (err)1272				goto cleanup;1273		}1274 1275		i--;1276	}1277 1278	/* insert new index */1279	err = ext4_ext_insert_index(handle, inode, path + at,1280				    le32_to_cpu(border), newblock);1281 1282cleanup:1283	if (bh) {1284		if (buffer_locked(bh))1285			unlock_buffer(bh);1286		brelse(bh);1287	}1288 1289	if (err) {1290		/* free all allocated blocks in error case */1291		for (i = 0; i < depth; i++) {1292			if (!ablocks[i])1293				continue;1294			ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,1295					 EXT4_FREE_BLOCKS_METADATA);1296		}1297	}1298	kfree(ablocks);1299 1300	return err;1301}1302 1303/*1304 * ext4_ext_grow_indepth:1305 * implements tree growing procedure:1306 * - allocates new block1307 * - moves top-level data (index block or leaf) into the new block1308 * - initializes new top-level, creating index that points to the1309 *   just created block1310 */1311static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,1312				 unsigned int flags)1313{1314	struct ext4_extent_header *neh;1315	struct buffer_head *bh;1316	ext4_fsblk_t newblock, goal = 0;1317	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;1318	int err = 0;1319	size_t ext_size = 0;1320 1321	/* Try to prepend new index to old one */1322	if (ext_depth(inode))1323		goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));1324	if (goal > le32_to_cpu(es->s_first_data_block)) {1325		flags |= EXT4_MB_HINT_TRY_GOAL;1326		goal--;1327	} else1328		goal = ext4_inode_to_goal_block(inode);1329	newblock = ext4_new_meta_blocks(handle, inode, goal, flags,1330					NULL, &err);1331	if (newblock == 0)1332		return err;1333 1334	bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);1335	if (unlikely(!bh))1336		return -ENOMEM;1337	lock_buffer(bh);1338 1339	err = ext4_journal_get_create_access(handle, inode->i_sb, bh,1340					     EXT4_JTR_NONE);1341	if (err) {1342		unlock_buffer(bh);1343		goto out;1344	}1345 1346	ext_size = sizeof(EXT4_I(inode)->i_data);1347	/* move top-level index/leaf into new block */1348	memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);1349	/* zero out unused area in the extent block */1350	memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);1351 1352	/* set size of new block */1353	neh = ext_block_hdr(bh);1354	/* old root could have indexes or leaves1355	 * so calculate e_max right way */1356	if (ext_depth(inode))1357		neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));1358	else1359		neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));1360	neh->eh_magic = EXT4_EXT_MAGIC;1361	ext4_extent_block_csum_set(inode, neh);1362	set_buffer_uptodate(bh);1363	set_buffer_verified(bh);1364	unlock_buffer(bh);1365 1366	err = ext4_handle_dirty_metadata(handle, inode, bh);1367	if (err)1368		goto out;1369 1370	/* Update top-level index: num,max,pointer */1371	neh = ext_inode_hdr(inode);1372	neh->eh_entries = cpu_to_le16(1);1373	ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);1374	if (neh->eh_depth == 0) {1375		/* Root extent block becomes index block */1376		neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));1377		EXT_FIRST_INDEX(neh)->ei_block =1378			EXT_FIRST_EXTENT(neh)->ee_block;1379	}1380	ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %llu\n",1381		  le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),1382		  le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),1383		  ext4_idx_pblock(EXT_FIRST_INDEX(neh)));1384 1385	le16_add_cpu(&neh->eh_depth, 1);1386	err = ext4_mark_inode_dirty(handle, inode);1387out:1388	brelse(bh);1389 1390	return err;1391}1392 1393/*1394 * ext4_ext_create_new_leaf:1395 * finds empty index and adds new leaf.1396 * if no free index is found, then it requests in-depth growing.1397 */1398static struct ext4_ext_path *1399ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,1400			 unsigned int mb_flags, unsigned int gb_flags,1401			 struct ext4_ext_path *path,1402			 struct ext4_extent *newext)1403{1404	struct ext4_ext_path *curp;1405	int depth, i, err = 0;1406	ext4_lblk_t ee_block = le32_to_cpu(newext->ee_block);1407 1408repeat:1409	i = depth = ext_depth(inode);1410 1411	/* walk up to the tree and look for free index entry */1412	curp = path + depth;1413	while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {1414		i--;1415		curp--;1416	}1417 1418	/* we use already allocated block for index block,1419	 * so subsequent data blocks should be contiguous */1420	if (EXT_HAS_FREE_INDEX(curp)) {1421		/* if we found index with free entry, then use that1422		 * entry: create all needed subtree and add new leaf */1423		err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);1424		if (err)1425			goto errout;1426 1427		/* refill path */1428		path = ext4_find_extent(inode, ee_block, path, gb_flags);1429		return path;1430	}1431 1432	/* tree is full, time to grow in depth */1433	err = ext4_ext_grow_indepth(handle, inode, mb_flags);1434	if (err)1435		goto errout;1436 1437	/* refill path */1438	path = ext4_find_extent(inode, ee_block, path, gb_flags);1439	if (IS_ERR(path))1440		return path;1441 1442	/*1443	 * only first (depth 0 -> 1) produces free space;1444	 * in all other cases we have to split the grown tree1445	 */1446	depth = ext_depth(inode);1447	if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {1448		/* now we need to split */1449		goto repeat;1450	}1451 1452	return path;1453 1454errout:1455	ext4_free_ext_path(path);1456	return ERR_PTR(err);1457}1458 1459/*1460 * search the closest allocated block to the left for *logical1461 * and returns it at @logical + it's physical address at @phys1462 * if *logical is the smallest allocated block, the function1463 * returns 0 at @phys1464 * return value contains 0 (success) or error code1465 */1466static int ext4_ext_search_left(struct inode *inode,1467				struct ext4_ext_path *path,1468				ext4_lblk_t *logical, ext4_fsblk_t *phys)1469{1470	struct ext4_extent_idx *ix;1471	struct ext4_extent *ex;1472	int depth, ee_len;1473 1474	if (unlikely(path == NULL)) {1475		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);1476		return -EFSCORRUPTED;1477	}1478	depth = path->p_depth;1479	*phys = 0;1480 1481	if (depth == 0 && path->p_ext == NULL)1482		return 0;1483 1484	/* usually extent in the path covers blocks smaller1485	 * then *logical, but it can be that extent is the1486	 * first one in the file */1487 1488	ex = path[depth].p_ext;1489	ee_len = ext4_ext_get_actual_len(ex);1490	if (*logical < le32_to_cpu(ex->ee_block)) {1491		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {1492			EXT4_ERROR_INODE(inode,1493					 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",1494					 *logical, le32_to_cpu(ex->ee_block));1495			return -EFSCORRUPTED;1496		}1497		while (--depth >= 0) {1498			ix = path[depth].p_idx;1499			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {1500				EXT4_ERROR_INODE(inode,1501				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",1502				  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,1503				  le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),1504				  depth);1505				return -EFSCORRUPTED;1506			}1507		}1508		return 0;1509	}1510 1511	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {1512		EXT4_ERROR_INODE(inode,1513				 "logical %d < ee_block %d + ee_len %d!",1514				 *logical, le32_to_cpu(ex->ee_block), ee_len);1515		return -EFSCORRUPTED;1516	}1517 1518	*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;1519	*phys = ext4_ext_pblock(ex) + ee_len - 1;1520	return 0;1521}1522 1523/*1524 * Search the closest allocated block to the right for *logical1525 * and returns it at @logical + it's physical address at @phys.1526 * If not exists, return 0 and @phys is set to 0. We will return1527 * 1 which means we found an allocated block and ret_ex is valid.1528 * Or return a (< 0) error code.1529 */1530static int ext4_ext_search_right(struct inode *inode,1531				 struct ext4_ext_path *path,1532				 ext4_lblk_t *logical, ext4_fsblk_t *phys,1533				 struct ext4_extent *ret_ex)1534{1535	struct buffer_head *bh = NULL;1536	struct ext4_extent_header *eh;1537	struct ext4_extent_idx *ix;1538	struct ext4_extent *ex;1539	int depth;	/* Note, NOT eh_depth; depth from top of tree */1540	int ee_len;1541 1542	if (unlikely(path == NULL)) {1543		EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);1544		return -EFSCORRUPTED;1545	}1546	depth = path->p_depth;1547	*phys = 0;1548 1549	if (depth == 0 && path->p_ext == NULL)1550		return 0;1551 1552	/* usually extent in the path covers blocks smaller1553	 * then *logical, but it can be that extent is the1554	 * first one in the file */1555 1556	ex = path[depth].p_ext;1557	ee_len = ext4_ext_get_actual_len(ex);1558	if (*logical < le32_to_cpu(ex->ee_block)) {1559		if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {1560			EXT4_ERROR_INODE(inode,1561					 "first_extent(path[%d].p_hdr) != ex",1562					 depth);1563			return -EFSCORRUPTED;1564		}1565		while (--depth >= 0) {1566			ix = path[depth].p_idx;1567			if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {1568				EXT4_ERROR_INODE(inode,1569						 "ix != EXT_FIRST_INDEX *logical %d!",1570						 *logical);1571				return -EFSCORRUPTED;1572			}1573		}1574		goto found_extent;1575	}1576 1577	if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {1578		EXT4_ERROR_INODE(inode,1579				 "logical %d < ee_block %d + ee_len %d!",1580				 *logical, le32_to_cpu(ex->ee_block), ee_len);1581		return -EFSCORRUPTED;1582	}1583 1584	if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {1585		/* next allocated block in this leaf */1586		ex++;1587		goto found_extent;1588	}1589 1590	/* go up and search for index to the right */1591	while (--depth >= 0) {1592		ix = path[depth].p_idx;1593		if (ix != EXT_LAST_INDEX(path[depth].p_hdr))1594			goto got_index;1595	}1596 1597	/* we've gone up to the root and found no index to the right */1598	return 0;1599 1600got_index:1601	/* we've found index to the right, let's1602	 * follow it and find the closest allocated1603	 * block to the right */1604	ix++;1605	while (++depth < path->p_depth) {1606		/* subtract from p_depth to get proper eh_depth */1607		bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);1608		if (IS_ERR(bh))1609			return PTR_ERR(bh);1610		eh = ext_block_hdr(bh);1611		ix = EXT_FIRST_INDEX(eh);1612		put_bh(bh);1613	}1614 1615	bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);1616	if (IS_ERR(bh))1617		return PTR_ERR(bh);1618	eh = ext_block_hdr(bh);1619	ex = EXT_FIRST_EXTENT(eh);1620found_extent:1621	*logical = le32_to_cpu(ex->ee_block);1622	*phys = ext4_ext_pblock(ex);1623	if (ret_ex)1624		*ret_ex = *ex;1625	if (bh)1626		put_bh(bh);1627	return 1;1628}1629 1630/*1631 * ext4_ext_next_allocated_block:1632 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.1633 * NOTE: it considers block number from index entry as1634 * allocated block. Thus, index entries have to be consistent1635 * with leaves.1636 */1637ext4_lblk_t1638ext4_ext_next_allocated_block(struct ext4_ext_path *path)1639{1640	int depth;1641 1642	BUG_ON(path == NULL);1643	depth = path->p_depth;1644 1645	if (depth == 0 && path->p_ext == NULL)1646		return EXT_MAX_BLOCKS;1647 1648	while (depth >= 0) {1649		struct ext4_ext_path *p = &path[depth];1650 1651		if (depth == path->p_depth) {1652			/* leaf */1653			if (p->p_ext && p->p_ext != EXT_LAST_EXTENT(p->p_hdr))1654				return le32_to_cpu(p->p_ext[1].ee_block);1655		} else {1656			/* index */1657			if (p->p_idx != EXT_LAST_INDEX(p->p_hdr))1658				return le32_to_cpu(p->p_idx[1].ei_block);1659		}1660		depth--;1661	}1662 1663	return EXT_MAX_BLOCKS;1664}1665 1666/*1667 * ext4_ext_next_leaf_block:1668 * returns first allocated block from next leaf or EXT_MAX_BLOCKS1669 */1670static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)1671{1672	int depth;1673 1674	BUG_ON(path == NULL);1675	depth = path->p_depth;1676 1677	/* zero-tree has no leaf blocks at all */1678	if (depth == 0)1679		return EXT_MAX_BLOCKS;1680 1681	/* go to index block */1682	depth--;1683 1684	while (depth >= 0) {1685		if (path[depth].p_idx !=1686				EXT_LAST_INDEX(path[depth].p_hdr))1687			return (ext4_lblk_t)1688				le32_to_cpu(path[depth].p_idx[1].ei_block);1689		depth--;1690	}1691 1692	return EXT_MAX_BLOCKS;1693}1694 1695/*1696 * ext4_ext_correct_indexes:1697 * if leaf gets modified and modified extent is first in the leaf,1698 * then we have to correct all indexes above.1699 * TODO: do we need to correct tree in all cases?1700 */1701static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,1702				struct ext4_ext_path *path)1703{1704	struct ext4_extent_header *eh;1705	int depth = ext_depth(inode);1706	struct ext4_extent *ex;1707	__le32 border;1708	int k, err = 0;1709 1710	eh = path[depth].p_hdr;1711	ex = path[depth].p_ext;1712 1713	if (unlikely(ex == NULL || eh == NULL)) {1714		EXT4_ERROR_INODE(inode,1715				 "ex %p == NULL or eh %p == NULL", ex, eh);1716		return -EFSCORRUPTED;1717	}1718 1719	if (depth == 0) {1720		/* there is no tree at all */1721		return 0;1722	}1723 1724	if (ex != EXT_FIRST_EXTENT(eh)) {1725		/* we correct tree if first leaf got modified only */1726		return 0;1727	}1728 1729	/*1730	 * TODO: we need correction if border is smaller than current one1731	 */1732	k = depth - 1;1733	border = path[depth].p_ext->ee_block;1734	err = ext4_ext_get_access(handle, inode, path + k);1735	if (err)1736		return err;1737	path[k].p_idx->ei_block = border;1738	err = ext4_ext_dirty(handle, inode, path + k);1739	if (err)1740		return err;1741 1742	while (k--) {1743		/* change all left-side indexes */1744		if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))1745			break;1746		err = ext4_ext_get_access(handle, inode, path + k);1747		if (err)1748			goto clean;1749		path[k].p_idx->ei_block = border;1750		err = ext4_ext_dirty(handle, inode, path + k);1751		if (err)1752			goto clean;1753	}1754	return 0;1755 1756clean:1757	/*1758	 * The path[k].p_bh is either unmodified or with no verified bit1759	 * set (see ext4_ext_get_access()). So just clear the verified bit1760	 * of the successfully modified extents buffers, which will force1761	 * these extents to be checked to avoid using inconsistent data.1762	 */1763	while (++k < depth)1764		clear_buffer_verified(path[k].p_bh);1765 1766	return err;1767}1768 1769static int ext4_can_extents_be_merged(struct inode *inode,1770				      struct ext4_extent *ex1,1771				      struct ext4_extent *ex2)1772{1773	unsigned short ext1_ee_len, ext2_ee_len;1774 1775	if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))1776		return 0;1777 1778	ext1_ee_len = ext4_ext_get_actual_len(ex1);1779	ext2_ee_len = ext4_ext_get_actual_len(ex2);1780 1781	if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=1782			le32_to_cpu(ex2->ee_block))1783		return 0;1784 1785	if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)1786		return 0;1787 1788	if (ext4_ext_is_unwritten(ex1) &&1789	    ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)1790		return 0;1791#ifdef AGGRESSIVE_TEST1792	if (ext1_ee_len >= 4)1793		return 0;1794#endif1795 1796	if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))1797		return 1;1798	return 0;1799}1800 1801/*1802 * This function tries to merge the "ex" extent to the next extent in the tree.1803 * It always tries to merge towards right. If you want to merge towards1804 * left, pass "ex - 1" as argument instead of "ex".1805 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns1806 * 1 if they got merged.1807 */1808static int ext4_ext_try_to_merge_right(struct inode *inode,1809				 struct ext4_ext_path *path,1810				 struct ext4_extent *ex)1811{1812	struct ext4_extent_header *eh;1813	unsigned int depth, len;1814	int merge_done = 0, unwritten;1815 1816	depth = ext_depth(inode);1817	BUG_ON(path[depth].p_hdr == NULL);1818	eh = path[depth].p_hdr;1819 1820	while (ex < EXT_LAST_EXTENT(eh)) {1821		if (!ext4_can_extents_be_merged(inode, ex, ex + 1))1822			break;1823		/* merge with next extent! */1824		unwritten = ext4_ext_is_unwritten(ex);1825		ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)1826				+ ext4_ext_get_actual_len(ex + 1));1827		if (unwritten)1828			ext4_ext_mark_unwritten(ex);1829 1830		if (ex + 1 < EXT_LAST_EXTENT(eh)) {1831			len = (EXT_LAST_EXTENT(eh) - ex - 1)1832				* sizeof(struct ext4_extent);1833			memmove(ex + 1, ex + 2, len);1834		}1835		le16_add_cpu(&eh->eh_entries, -1);1836		merge_done = 1;1837		WARN_ON(eh->eh_entries == 0);1838		if (!eh->eh_entries)1839			EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");1840	}1841 1842	return merge_done;1843}1844 1845/*1846 * This function does a very simple check to see if we can collapse1847 * an extent tree with a single extent tree leaf block into the inode.1848 */1849static void ext4_ext_try_to_merge_up(handle_t *handle,1850				     struct inode *inode,1851				     struct ext4_ext_path *path)1852{1853	size_t s;1854	unsigned max_root = ext4_ext_space_root(inode, 0);1855	ext4_fsblk_t blk;1856 1857	if ((path[0].p_depth != 1) ||1858	    (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||1859	    (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))1860		return;1861 1862	/*1863	 * We need to modify the block allocation bitmap and the block1864	 * group descriptor to release the extent tree block.  If we1865	 * can't get the journal credits, give up.1866	 */1867	if (ext4_journal_extend(handle, 2,1868			ext4_free_metadata_revoke_credits(inode->i_sb, 1)))1869		return;1870 1871	/*1872	 * Copy the extent data up to the inode1873	 */1874	blk = ext4_idx_pblock(path[0].p_idx);1875	s = le16_to_cpu(path[1].p_hdr->eh_entries) *1876		sizeof(struct ext4_extent_idx);1877	s += sizeof(struct ext4_extent_header);1878 1879	path[1].p_maxdepth = path[0].p_maxdepth;1880	memcpy(path[0].p_hdr, path[1].p_hdr, s);1881	path[0].p_depth = 0;1882	path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +1883		(path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));1884	path[0].p_hdr->eh_max = cpu_to_le16(max_root);1885 1886	ext4_ext_path_brelse(path + 1);1887	ext4_free_blocks(handle, inode, NULL, blk, 1,1888			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);1889}1890 1891/*1892 * This function tries to merge the @ex extent to neighbours in the tree, then1893 * tries to collapse the extent tree into the inode.1894 */1895static void ext4_ext_try_to_merge(handle_t *handle,1896				  struct inode *inode,1897				  struct ext4_ext_path *path,1898				  struct ext4_extent *ex)1899{1900	struct ext4_extent_header *eh;1901	unsigned int depth;1902	int merge_done = 0;1903 1904	depth = ext_depth(inode);1905	BUG_ON(path[depth].p_hdr == NULL);1906	eh = path[depth].p_hdr;1907 1908	if (ex > EXT_FIRST_EXTENT(eh))1909		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);1910 1911	if (!merge_done)1912		(void) ext4_ext_try_to_merge_right(inode, path, ex);1913 1914	ext4_ext_try_to_merge_up(handle, inode, path);1915}1916 1917/*1918 * check if a portion of the "newext" extent overlaps with an1919 * existing extent.1920 *1921 * If there is an overlap discovered, it updates the length of the newext1922 * such that there will be no overlap, and then returns 1.1923 * If there is no overlap found, it returns 0.1924 */1925static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,1926					   struct inode *inode,1927					   struct ext4_extent *newext,1928					   struct ext4_ext_path *path)1929{1930	ext4_lblk_t b1, b2;1931	unsigned int depth, len1;1932	unsigned int ret = 0;1933 1934	b1 = le32_to_cpu(newext->ee_block);1935	len1 = ext4_ext_get_actual_len(newext);1936	depth = ext_depth(inode);1937	if (!path[depth].p_ext)1938		goto out;1939	b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));1940 1941	/*1942	 * get the next allocated block if the extent in the path1943	 * is before the requested block(s)1944	 */1945	if (b2 < b1) {1946		b2 = ext4_ext_next_allocated_block(path);1947		if (b2 == EXT_MAX_BLOCKS)1948			goto out;1949		b2 = EXT4_LBLK_CMASK(sbi, b2);1950	}1951 1952	/* check for wrap through zero on extent logical start block*/1953	if (b1 + len1 < b1) {1954		len1 = EXT_MAX_BLOCKS - b1;1955		newext->ee_len = cpu_to_le16(len1);1956		ret = 1;1957	}1958 1959	/* check for overlap */1960	if (b1 + len1 > b2) {1961		newext->ee_len = cpu_to_le16(b2 - b1);1962		ret = 1;1963	}1964out:1965	return ret;1966}1967 1968/*1969 * ext4_ext_insert_extent:1970 * tries to merge requested extent into the existing extent or1971 * inserts requested extent as new one into the tree,1972 * creating new leaf in the no-space case.1973 */1974struct ext4_ext_path *1975ext4_ext_insert_extent(handle_t *handle, struct inode *inode,1976		       struct ext4_ext_path *path,1977		       struct ext4_extent *newext, int gb_flags)1978{1979	struct ext4_extent_header *eh;1980	struct ext4_extent *ex, *fex;1981	struct ext4_extent *nearex; /* nearest extent */1982	int depth, len, err = 0;1983	ext4_lblk_t next;1984	int mb_flags = 0, unwritten;1985 1986	if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)1987		mb_flags |= EXT4_MB_DELALLOC_RESERVED;1988	if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {1989		EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");1990		err = -EFSCORRUPTED;1991		goto errout;1992	}1993	depth = ext_depth(inode);1994	ex = path[depth].p_ext;1995	eh = path[depth].p_hdr;1996	if (unlikely(path[depth].p_hdr == NULL)) {1997		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);1998		err = -EFSCORRUPTED;1999		goto errout;2000	}2001 2002	/* try to insert block into found extent and return */2003	if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {2004 2005		/*2006		 * Try to see whether we should rather test the extent on2007		 * right from ex, or from the left of ex. This is because2008		 * ext4_find_extent() can return either extent on the2009		 * left, or on the right from the searched position. This2010		 * will make merging more effective.2011		 */2012		if (ex < EXT_LAST_EXTENT(eh) &&2013		    (le32_to_cpu(ex->ee_block) +2014		    ext4_ext_get_actual_len(ex) <2015		    le32_to_cpu(newext->ee_block))) {2016			ex += 1;2017			goto prepend;2018		} else if ((ex > EXT_FIRST_EXTENT(eh)) &&2019			   (le32_to_cpu(newext->ee_block) +2020			   ext4_ext_get_actual_len(newext) <2021			   le32_to_cpu(ex->ee_block)))2022			ex -= 1;2023 2024		/* Try to append newex to the ex */2025		if (ext4_can_extents_be_merged(inode, ex, newext)) {2026			ext_debug(inode, "append [%d]%d block to %u:[%d]%d"2027				  "(from %llu)\n",2028				  ext4_ext_is_unwritten(newext),2029				  ext4_ext_get_actual_len(newext),2030				  le32_to_cpu(ex->ee_block),2031				  ext4_ext_is_unwritten(ex),2032				  ext4_ext_get_actual_len(ex),2033				  ext4_ext_pblock(ex));2034			err = ext4_ext_get_access(handle, inode,2035						  path + depth);2036			if (err)2037				goto errout;2038			unwritten = ext4_ext_is_unwritten(ex);2039			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)2040					+ ext4_ext_get_actual_len(newext));2041			if (unwritten)2042				ext4_ext_mark_unwritten(ex);2043			nearex = ex;2044			goto merge;2045		}2046 2047prepend:2048		/* Try to prepend newex to the ex */2049		if (ext4_can_extents_be_merged(inode, newext, ex)) {2050			ext_debug(inode, "prepend %u[%d]%d block to %u:[%d]%d"2051				  "(from %llu)\n",2052				  le32_to_cpu(newext->ee_block),2053				  ext4_ext_is_unwritten(newext),2054				  ext4_ext_get_actual_len(newext),2055				  le32_to_cpu(ex->ee_block),2056				  ext4_ext_is_unwritten(ex),2057				  ext4_ext_get_actual_len(ex),2058				  ext4_ext_pblock(ex));2059			err = ext4_ext_get_access(handle, inode,2060						  path + depth);2061			if (err)2062				goto errout;2063 2064			unwritten = ext4_ext_is_unwritten(ex);2065			ex->ee_block = newext->ee_block;2066			ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));2067			ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)2068					+ ext4_ext_get_actual_len(newext));2069			if (unwritten)2070				ext4_ext_mark_unwritten(ex);2071			nearex = ex;2072			goto merge;2073		}2074	}2075 2076	depth = ext_depth(inode);2077	eh = path[depth].p_hdr;2078	if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))2079		goto has_space;2080 2081	/* probably next leaf has space for us? */2082	fex = EXT_LAST_EXTENT(eh);2083	next = EXT_MAX_BLOCKS;2084	if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))2085		next = ext4_ext_next_leaf_block(path);2086	if (next != EXT_MAX_BLOCKS) {2087		struct ext4_ext_path *npath;2088 2089		ext_debug(inode, "next leaf block - %u\n", next);2090		npath = ext4_find_extent(inode, next, NULL, gb_flags);2091		if (IS_ERR(npath)) {2092			err = PTR_ERR(npath);2093			goto errout;2094		}2095		BUG_ON(npath->p_depth != path->p_depth);2096		eh = npath[depth].p_hdr;2097		if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {2098			ext_debug(inode, "next leaf isn't full(%d)\n",2099				  le16_to_cpu(eh->eh_entries));2100			ext4_free_ext_path(path);2101			path = npath;2102			goto has_space;2103		}2104		ext_debug(inode, "next leaf has no free space(%d,%d)\n",2105			  le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));2106		ext4_free_ext_path(npath);2107	}2108 2109	/*2110	 * There is no free space in the found leaf.2111	 * We're gonna add a new leaf in the tree.2112	 */2113	if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)2114		mb_flags |= EXT4_MB_USE_RESERVED;2115	path = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,2116					path, newext);2117	if (IS_ERR(path))2118		return path;2119	depth = ext_depth(inode);2120	eh = path[depth].p_hdr;2121 2122has_space:2123	nearex = path[depth].p_ext;2124 2125	err = ext4_ext_get_access(handle, inode, path + depth);2126	if (err)2127		goto errout;2128 2129	if (!nearex) {2130		/* there is no extent in this leaf, create first one */2131		ext_debug(inode, "first extent in the leaf: %u:%llu:[%d]%d\n",2132				le32_to_cpu(newext->ee_block),2133				ext4_ext_pblock(newext),2134				ext4_ext_is_unwritten(newext),2135				ext4_ext_get_actual_len(newext));2136		nearex = EXT_FIRST_EXTENT(eh);2137	} else {2138		if (le32_to_cpu(newext->ee_block)2139			   > le32_to_cpu(nearex->ee_block)) {2140			/* Insert after */2141			ext_debug(inode, "insert %u:%llu:[%d]%d before: "2142					"nearest %p\n",2143					le32_to_cpu(newext->ee_block),2144					ext4_ext_pblock(newext),2145					ext4_ext_is_unwritten(newext),2146					ext4_ext_get_actual_len(newext),2147					nearex);2148			nearex++;2149		} else {2150			/* Insert before */2151			BUG_ON(newext->ee_block == nearex->ee_block);2152			ext_debug(inode, "insert %u:%llu:[%d]%d after: "2153					"nearest %p\n",2154					le32_to_cpu(newext->ee_block),2155					ext4_ext_pblock(newext),2156					ext4_ext_is_unwritten(newext),2157					ext4_ext_get_actual_len(newext),2158					nearex);2159		}2160		len = EXT_LAST_EXTENT(eh) - nearex + 1;2161		if (len > 0) {2162			ext_debug(inode, "insert %u:%llu:[%d]%d: "2163					"move %d extents from 0x%p to 0x%p\n",2164					le32_to_cpu(newext->ee_block),2165					ext4_ext_pblock(newext),2166					ext4_ext_is_unwritten(newext),2167					ext4_ext_get_actual_len(newext),2168					len, nearex, nearex + 1);2169			memmove(nearex + 1, nearex,2170				len * sizeof(struct ext4_extent));2171		}2172	}2173 2174	le16_add_cpu(&eh->eh_entries, 1);2175	path[depth].p_ext = nearex;2176	nearex->ee_block = newext->ee_block;2177	ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));2178	nearex->ee_len = newext->ee_len;2179 2180merge:2181	/* try to merge extents */2182	if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))2183		ext4_ext_try_to_merge(handle, inode, path, nearex);2184 2185	/* time to correct all indexes above */2186	err = ext4_ext_correct_indexes(handle, inode, path);2187	if (err)2188		goto errout;2189 2190	err = ext4_ext_dirty(handle, inode, path + path->p_depth);2191	if (err)2192		goto errout;2193 2194	return path;2195 2196errout:2197	ext4_free_ext_path(path);2198	return ERR_PTR(err);2199}2200 2201static int ext4_fill_es_cache_info(struct inode *inode,2202				   ext4_lblk_t block, ext4_lblk_t num,2203				   struct fiemap_extent_info *fieinfo)2204{2205	ext4_lblk_t next, end = block + num - 1;2206	struct extent_status es;2207	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;2208	unsigned int flags;2209	int err;2210 2211	while (block <= end) {2212		next = 0;2213		flags = 0;2214		if (!ext4_es_lookup_extent(inode, block, &next, &es))2215			break;2216		if (ext4_es_is_unwritten(&es))2217			flags |= FIEMAP_EXTENT_UNWRITTEN;2218		if (ext4_es_is_delayed(&es))2219			flags |= (FIEMAP_EXTENT_DELALLOC |2220				  FIEMAP_EXTENT_UNKNOWN);2221		if (ext4_es_is_hole(&es))2222			flags |= EXT4_FIEMAP_EXTENT_HOLE;2223		if (next == 0)2224			flags |= FIEMAP_EXTENT_LAST;2225		if (flags & (FIEMAP_EXTENT_DELALLOC|2226			     EXT4_FIEMAP_EXTENT_HOLE))2227			es.es_pblk = 0;2228		else2229			es.es_pblk = ext4_es_pblock(&es);2230		err = fiemap_fill_next_extent(fieinfo,2231				(__u64)es.es_lblk << blksize_bits,2232				(__u64)es.es_pblk << blksize_bits,2233				(__u64)es.es_len << blksize_bits,2234				flags);2235		if (next == 0)2236			break;2237		block = next;2238		if (err < 0)2239			return err;2240		if (err == 1)2241			return 0;2242	}2243	return 0;2244}2245 2246 2247/*2248 * ext4_ext_find_hole - find hole around given block according to the given path2249 * @inode:	inode we lookup in2250 * @path:	path in extent tree to @lblk2251 * @lblk:	pointer to logical block around which we want to determine hole2252 *2253 * Determine hole length (and start if easily possible) around given logical2254 * block. We don't try too hard to find the beginning of the hole but @path2255 * actually points to extent before @lblk, we provide it.2256 *2257 * The function returns the length of a hole starting at @lblk. We update @lblk2258 * to the beginning of the hole if we managed to find it.2259 */2260static ext4_lblk_t ext4_ext_find_hole(struct inode *inode,2261				      struct ext4_ext_path *path,2262				      ext4_lblk_t *lblk)2263{2264	int depth = ext_depth(inode);2265	struct ext4_extent *ex;2266	ext4_lblk_t len;2267 2268	ex = path[depth].p_ext;2269	if (ex == NULL) {2270		/* there is no extent yet, so gap is [0;-] */2271		*lblk = 0;2272		len = EXT_MAX_BLOCKS;2273	} else if (*lblk < le32_to_cpu(ex->ee_block)) {2274		len = le32_to_cpu(ex->ee_block) - *lblk;2275	} else if (*lblk >= le32_to_cpu(ex->ee_block)2276			+ ext4_ext_get_actual_len(ex)) {2277		ext4_lblk_t next;2278 2279		*lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);2280		next = ext4_ext_next_allocated_block(path);2281		BUG_ON(next == *lblk);2282		len = next - *lblk;2283	} else {2284		BUG();2285	}2286	return len;2287}2288 2289/*2290 * ext4_ext_rm_idx:2291 * removes index from the index block.2292 */2293static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,2294			struct ext4_ext_path *path, int depth)2295{2296	int err;2297	ext4_fsblk_t leaf;2298	int k = depth - 1;2299 2300	/* free index block */2301	leaf = ext4_idx_pblock(path[k].p_idx);2302	if (unlikely(path[k].p_hdr->eh_entries == 0)) {2303		EXT4_ERROR_INODE(inode, "path[%d].p_hdr->eh_entries == 0", k);2304		return -EFSCORRUPTED;2305	}2306	err = ext4_ext_get_access(handle, inode, path + k);2307	if (err)2308		return err;2309 2310	if (path[k].p_idx != EXT_LAST_INDEX(path[k].p_hdr)) {2311		int len = EXT_LAST_INDEX(path[k].p_hdr) - path[k].p_idx;2312		len *= sizeof(struct ext4_extent_idx);2313		memmove(path[k].p_idx, path[k].p_idx + 1, len);2314	}2315 2316	le16_add_cpu(&path[k].p_hdr->eh_entries, -1);2317	err = ext4_ext_dirty(handle, inode, path + k);2318	if (err)2319		return err;2320	ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf);2321	trace_ext4_ext_rm_idx(inode, leaf);2322 2323	ext4_free_blocks(handle, inode, NULL, leaf, 1,2324			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);2325 2326	while (--k >= 0) {2327		if (path[k + 1].p_idx != EXT_FIRST_INDEX(path[k + 1].p_hdr))2328			break;2329		err = ext4_ext_get_access(handle, inode, path + k);2330		if (err)2331			goto clean;2332		path[k].p_idx->ei_block = path[k + 1].p_idx->ei_block;2333		err = ext4_ext_dirty(handle, inode, path + k);2334		if (err)2335			goto clean;2336	}2337	return 0;2338 2339clean:2340	/*2341	 * The path[k].p_bh is either unmodified or with no verified bit2342	 * set (see ext4_ext_get_access()). So just clear the verified bit2343	 * of the successfully modified extents buffers, which will force2344	 * these extents to be checked to avoid using inconsistent data.2345	 */2346	while (++k < depth)2347		clear_buffer_verified(path[k].p_bh);2348 2349	return err;2350}2351 2352/*2353 * ext4_ext_calc_credits_for_single_extent:2354 * This routine returns max. credits that needed to insert an extent2355 * to the extent tree.2356 * When pass the actual path, the caller should calculate credits2357 * under i_data_sem.2358 */2359int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,2360						struct ext4_ext_path *path)2361{2362	if (path) {2363		int depth = ext_depth(inode);2364		int ret = 0;2365 2366		/* probably there is space in leaf? */2367		if (le16_to_cpu(path[depth].p_hdr->eh_entries)2368				< le16_to_cpu(path[depth].p_hdr->eh_max)) {2369 2370			/*2371			 *  There are some space in the leaf tree, no2372			 *  need to account for leaf block credit2373			 *2374			 *  bitmaps and block group descriptor blocks2375			 *  and other metadata blocks still need to be2376			 *  accounted.2377			 */2378			/* 1 bitmap, 1 block group descriptor */2379			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);2380			return ret;2381		}2382	}2383 2384	return ext4_chunk_trans_blocks(inode, nrblocks);2385}2386 2387/*2388 * How many index/leaf blocks need to change/allocate to add @extents extents?2389 *2390 * If we add a single extent, then in the worse case, each tree level2391 * index/leaf need to be changed in case of the tree split.2392 *2393 * If more extents are inserted, they could cause the whole tree split more2394 * than once, but this is really rare.2395 */2396int ext4_ext_index_trans_blocks(struct inode *inode, int extents)2397{2398	int index;2399	int depth;2400 2401	/* If we are converting the inline data, only one is needed here. */2402	if (ext4_has_inline_data(inode))2403		return 1;2404 2405	depth = ext_depth(inode);2406 2407	if (extents <= 1)2408		index = depth * 2;2409	else2410		index = depth * 3;2411 2412	return index;2413}2414 2415static inline int get_default_free_blocks_flags(struct inode *inode)2416{2417	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||2418	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))2419		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;2420	else if (ext4_should_journal_data(inode))2421		return EXT4_FREE_BLOCKS_FORGET;2422	return 0;2423}2424 2425/*2426 * ext4_rereserve_cluster - increment the reserved cluster count when2427 *                          freeing a cluster with a pending reservation2428 *2429 * @inode - file containing the cluster2430 * @lblk - logical block in cluster to be reserved2431 *2432 * Increments the reserved cluster count and adjusts quota in a bigalloc2433 * file system when freeing a partial cluster containing at least one2434 * delayed and unwritten block.  A partial cluster meeting that2435 * requirement will have a pending reservation.  If so, the2436 * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to2437 * defer reserved and allocated space accounting to a subsequent call2438 * to this function.2439 */2440static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)2441{2442	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);2443	struct ext4_inode_info *ei = EXT4_I(inode);2444 2445	dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));2446 2447	spin_lock(&ei->i_block_reservation_lock);2448	ei->i_reserved_data_blocks++;2449	percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);2450	spin_unlock(&ei->i_block_reservation_lock);2451 2452	percpu_counter_add(&sbi->s_freeclusters_counter, 1);2453	ext4_remove_pending(inode, lblk);2454}2455 2456static int ext4_remove_blocks(handle_t *handle, struct inode *inode,2457			      struct ext4_extent *ex,2458			      struct partial_cluster *partial,2459			      ext4_lblk_t from, ext4_lblk_t to)2460{2461	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);2462	unsigned short ee_len = ext4_ext_get_actual_len(ex);2463	ext4_fsblk_t last_pblk, pblk;2464	ext4_lblk_t num;2465	int flags;2466 2467	/* only extent tail removal is allowed */2468	if (from < le32_to_cpu(ex->ee_block) ||2469	    to != le32_to_cpu(ex->ee_block) + ee_len - 1) {2470		ext4_error(sbi->s_sb,2471			   "strange request: removal(2) %u-%u from %u:%u",2472			   from, to, le32_to_cpu(ex->ee_block), ee_len);2473		return 0;2474	}2475 2476#ifdef EXTENTS_STATS2477	spin_lock(&sbi->s_ext_stats_lock);2478	sbi->s_ext_blocks += ee_len;2479	sbi->s_ext_extents++;2480	if (ee_len < sbi->s_ext_min)2481		sbi->s_ext_min = ee_len;2482	if (ee_len > sbi->s_ext_max)2483		sbi->s_ext_max = ee_len;2484	if (ext_depth(inode) > sbi->s_depth_max)2485		sbi->s_depth_max = ext_depth(inode);2486	spin_unlock(&sbi->s_ext_stats_lock);2487#endif2488 2489	trace_ext4_remove_blocks(inode, ex, from, to, partial);2490 2491	/*2492	 * if we have a partial cluster, and it's different from the2493	 * cluster of the last block in the extent, we free it2494	 */2495	last_pblk = ext4_ext_pblock(ex) + ee_len - 1;2496 2497	if (partial->state != initial &&2498	    partial->pclu != EXT4_B2C(sbi, last_pblk)) {2499		if (partial->state == tofree) {2500			flags = get_default_free_blocks_flags(inode);2501			if (ext4_is_pending(inode, partial->lblk))2502				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;2503			ext4_free_blocks(handle, inode, NULL,2504					 EXT4_C2B(sbi, partial->pclu),2505					 sbi->s_cluster_ratio, flags);2506			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)2507				ext4_rereserve_cluster(inode, partial->lblk);2508		}2509		partial->state = initial;2510	}2511 2512	num = le32_to_cpu(ex->ee_block) + ee_len - from;2513	pblk = ext4_ext_pblock(ex) + ee_len - num;2514 2515	/*2516	 * We free the partial cluster at the end of the extent (if any),2517	 * unless the cluster is used by another extent (partial_cluster2518	 * state is nofree).  If a partial cluster exists here, it must be2519	 * shared with the last block in the extent.2520	 */2521	flags = get_default_free_blocks_flags(inode);2522 2523	/* partial, left end cluster aligned, right end unaligned */2524	if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&2525	    (EXT4_LBLK_CMASK(sbi, to) >= from) &&2526	    (partial->state != nofree)) {2527		if (ext4_is_pending(inode, to))2528			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;2529		ext4_free_blocks(handle, inode, NULL,2530				 EXT4_PBLK_CMASK(sbi, last_pblk),2531				 sbi->s_cluster_ratio, flags);2532		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)2533			ext4_rereserve_cluster(inode, to);2534		partial->state = initial;2535		flags = get_default_free_blocks_flags(inode);2536	}2537 2538	flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;2539 2540	/*2541	 * For bigalloc file systems, we never free a partial cluster2542	 * at the beginning of the extent.  Instead, we check to see if we2543	 * need to free it on a subsequent call to ext4_remove_blocks,2544	 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.2545	 */2546	flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;2547	ext4_free_blocks(handle, inode, NULL, pblk, num, flags);2548 2549	/* reset the partial cluster if we've freed past it */2550	if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))2551		partial->state = initial;2552 2553	/*2554	 * If we've freed the entire extent but the beginning is not left2555	 * cluster aligned and is not marked as ineligible for freeing we2556	 * record the partial cluster at the beginning of the extent.  It2557	 * wasn't freed by the preceding ext4_free_blocks() call, and we2558	 * need to look farther to the left to determine if it's to be freed2559	 * (not shared with another extent). Else, reset the partial2560	 * cluster - we're either  done freeing or the beginning of the2561	 * extent is left cluster aligned.2562	 */2563	if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {2564		if (partial->state == initial) {2565			partial->pclu = EXT4_B2C(sbi, pblk);2566			partial->lblk = from;2567			partial->state = tofree;2568		}2569	} else {2570		partial->state = initial;2571	}2572 2573	return 0;2574}2575 2576/*2577 * ext4_ext_rm_leaf() Removes the extents associated with the2578 * blocks appearing between "start" and "end".  Both "start"2579 * and "end" must appear in the same extent or EIO is returned.2580 *2581 * @handle: The journal handle2582 * @inode:  The files inode2583 * @path:   The path to the leaf2584 * @partial_cluster: The cluster which we'll have to free if all extents2585 *                   has been released from it.  However, if this value is2586 *                   negative, it's a cluster just to the right of the2587 *                   punched region and it must not be freed.2588 * @start:  The first block to remove2589 * @end:   The last block to remove2590 */2591static int2592ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,2593		 struct ext4_ext_path *path,2594		 struct partial_cluster *partial,2595		 ext4_lblk_t start, ext4_lblk_t end)2596{2597	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);2598	int err = 0, correct_index = 0;2599	int depth = ext_depth(inode), credits, revoke_credits;2600	struct ext4_extent_header *eh;2601	ext4_lblk_t a, b;2602	unsigned num;2603	ext4_lblk_t ex_ee_block;2604	unsigned short ex_ee_len;2605	unsigned unwritten = 0;2606	struct ext4_extent *ex;2607	ext4_fsblk_t pblk;2608 2609	/* the header must be checked already in ext4_ext_remove_space() */2610	ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);2611	if (!path[depth].p_hdr)2612		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);2613	eh = path[depth].p_hdr;2614	if (unlikely(path[depth].p_hdr == NULL)) {2615		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);2616		return -EFSCORRUPTED;2617	}2618	/* find where to start removing */2619	ex = path[depth].p_ext;2620	if (!ex)2621		ex = EXT_LAST_EXTENT(eh);2622 2623	ex_ee_block = le32_to_cpu(ex->ee_block);2624	ex_ee_len = ext4_ext_get_actual_len(ex);2625 2626	trace_ext4_ext_rm_leaf(inode, start, ex, partial);2627 2628	while (ex >= EXT_FIRST_EXTENT(eh) &&2629			ex_ee_block + ex_ee_len > start) {2630 2631		if (ext4_ext_is_unwritten(ex))2632			unwritten = 1;2633		else2634			unwritten = 0;2635 2636		ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,2637			  unwritten, ex_ee_len);2638		path[depth].p_ext = ex;2639 2640		a = max(ex_ee_block, start);2641		b = min(ex_ee_block + ex_ee_len - 1, end);2642 2643		ext_debug(inode, "  border %u:%u\n", a, b);2644 2645		/* If this extent is beyond the end of the hole, skip it */2646		if (end < ex_ee_block) {2647			/*2648			 * We're going to skip this extent and move to another,2649			 * so note that its first cluster is in use to avoid2650			 * freeing it when removing blocks.  Eventually, the2651			 * right edge of the truncated/punched region will2652			 * be just to the left.2653			 */2654			if (sbi->s_cluster_ratio > 1) {2655				pblk = ext4_ext_pblock(ex);2656				partial->pclu = EXT4_B2C(sbi, pblk);2657				partial->state = nofree;2658			}2659			ex--;2660			ex_ee_block = le32_to_cpu(ex->ee_block);2661			ex_ee_len = ext4_ext_get_actual_len(ex);2662			continue;2663		} else if (b != ex_ee_block + ex_ee_len - 1) {2664			EXT4_ERROR_INODE(inode,2665					 "can not handle truncate %u:%u "2666					 "on extent %u:%u",2667					 start, end, ex_ee_block,2668					 ex_ee_block + ex_ee_len - 1);2669			err = -EFSCORRUPTED;2670			goto out;2671		} else if (a != ex_ee_block) {2672			/* remove tail of the extent */2673			num = a - ex_ee_block;2674		} else {2675			/* remove whole extent: excellent! */2676			num = 0;2677		}2678		/*2679		 * 3 for leaf, sb, and inode plus 2 (bmap and group2680		 * descriptor) for each block group; assume two block2681		 * groups plus ex_ee_len/blocks_per_block_group for2682		 * the worst case2683		 */2684		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));2685		if (ex == EXT_FIRST_EXTENT(eh)) {2686			correct_index = 1;2687			credits += (ext_depth(inode)) + 1;2688		}2689		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);2690		/*2691		 * We may end up freeing some index blocks and data from the2692		 * punched range. Note that partial clusters are accounted for2693		 * by ext4_free_data_revoke_credits().2694		 */2695		revoke_credits =2696			ext4_free_metadata_revoke_credits(inode->i_sb,2697							  ext_depth(inode)) +2698			ext4_free_data_revoke_credits(inode, b - a + 1);2699 2700		err = ext4_datasem_ensure_credits(handle, inode, credits,2701						  credits, revoke_credits);2702		if (err) {2703			if (err > 0)2704				err = -EAGAIN;2705			goto out;2706		}2707 2708		err = ext4_ext_get_access(handle, inode, path + depth);2709		if (err)2710			goto out;2711 2712		err = ext4_remove_blocks(handle, inode, ex, partial, a, b);2713		if (err)2714			goto out;2715 2716		if (num == 0)2717			/* this extent is removed; mark slot entirely unused */2718			ext4_ext_store_pblock(ex, 0);2719 2720		ex->ee_len = cpu_to_le16(num);2721		/*2722		 * Do not mark unwritten if all the blocks in the2723		 * extent have been removed.2724		 */2725		if (unwritten && num)2726			ext4_ext_mark_unwritten(ex);2727		/*2728		 * If the extent was completely released,2729		 * we need to remove it from the leaf2730		 */2731		if (num == 0) {2732			if (end != EXT_MAX_BLOCKS - 1) {2733				/*2734				 * For hole punching, we need to scoot all the2735				 * extents up when an extent is removed so that2736				 * we dont have blank extents in the middle2737				 */2738				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *2739					sizeof(struct ext4_extent));2740 2741				/* Now get rid of the one at the end */2742				memset(EXT_LAST_EXTENT(eh), 0,2743					sizeof(struct ext4_extent));2744			}2745			le16_add_cpu(&eh->eh_entries, -1);2746		}2747 2748		err = ext4_ext_dirty(handle, inode, path + depth);2749		if (err)2750			goto out;2751 2752		ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,2753				ext4_ext_pblock(ex));2754		ex--;2755		ex_ee_block = le32_to_cpu(ex->ee_block);2756		ex_ee_len = ext4_ext_get_actual_len(ex);2757	}2758 2759	if (correct_index && eh->eh_entries)2760		err = ext4_ext_correct_indexes(handle, inode, path);2761 2762	/*2763	 * If there's a partial cluster and at least one extent remains in2764	 * the leaf, free the partial cluster if it isn't shared with the2765	 * current extent.  If it is shared with the current extent2766	 * we reset the partial cluster because we've reached the start of the2767	 * truncated/punched region and we're done removing blocks.2768	 */2769	if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {2770		pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;2771		if (partial->pclu != EXT4_B2C(sbi, pblk)) {2772			int flags = get_default_free_blocks_flags(inode);2773 2774			if (ext4_is_pending(inode, partial->lblk))2775				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;2776			ext4_free_blocks(handle, inode, NULL,2777					 EXT4_C2B(sbi, partial->pclu),2778					 sbi->s_cluster_ratio, flags);2779			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)2780				ext4_rereserve_cluster(inode, partial->lblk);2781		}2782		partial->state = initial;2783	}2784 2785	/* if this leaf is free, then we should2786	 * remove it from index block above */2787	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)2788		err = ext4_ext_rm_idx(handle, inode, path, depth);2789 2790out:2791	return err;2792}2793 2794/*2795 * ext4_ext_more_to_rm:2796 * returns 1 if current index has to be freed (even partial)2797 */2798static int2799ext4_ext_more_to_rm(struct ext4_ext_path *path)2800{2801	BUG_ON(path->p_idx == NULL);2802 2803	if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))2804		return 0;2805 2806	/*2807	 * if truncate on deeper level happened, it wasn't partial,2808	 * so we have to consider current index for truncation2809	 */2810	if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)2811		return 0;2812	return 1;2813}2814 2815int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,2816			  ext4_lblk_t end)2817{2818	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);2819	int depth = ext_depth(inode);2820	struct ext4_ext_path *path = NULL;2821	struct partial_cluster partial;2822	handle_t *handle;2823	int i = 0, err = 0;2824 2825	partial.pclu = 0;2826	partial.lblk = 0;2827	partial.state = initial;2828 2829	ext_debug(inode, "truncate since %u to %u\n", start, end);2830 2831	/* probably first extent we're gonna free will be last in block */2832	handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,2833			depth + 1,2834			ext4_free_metadata_revoke_credits(inode->i_sb, depth));2835	if (IS_ERR(handle))2836		return PTR_ERR(handle);2837 2838again:2839	trace_ext4_ext_remove_space(inode, start, end, depth);2840 2841	/*2842	 * Check if we are removing extents inside the extent tree. If that2843	 * is the case, we are going to punch a hole inside the extent tree2844	 * so we have to check whether we need to split the extent covering2845	 * the last block to remove so we can easily remove the part of it2846	 * in ext4_ext_rm_leaf().2847	 */2848	if (end < EXT_MAX_BLOCKS - 1) {2849		struct ext4_extent *ex;2850		ext4_lblk_t ee_block, ex_end, lblk;2851		ext4_fsblk_t pblk;2852 2853		/* find extent for or closest extent to this block */2854		path = ext4_find_extent(inode, end, NULL,2855					EXT4_EX_NOCACHE | EXT4_EX_NOFAIL);2856		if (IS_ERR(path)) {2857			ext4_journal_stop(handle);2858			return PTR_ERR(path);2859		}2860		depth = ext_depth(inode);2861		/* Leaf not may not exist only if inode has no blocks at all */2862		ex = path[depth].p_ext;2863		if (!ex) {2864			if (depth) {2865				EXT4_ERROR_INODE(inode,2866						 "path[%d].p_hdr == NULL",2867						 depth);2868				err = -EFSCORRUPTED;2869			}2870			goto out;2871		}2872 2873		ee_block = le32_to_cpu(ex->ee_block);2874		ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;2875 2876		/*2877		 * See if the last block is inside the extent, if so split2878		 * the extent at 'end' block so we can easily remove the2879		 * tail of the first part of the split extent in2880		 * ext4_ext_rm_leaf().2881		 */2882		if (end >= ee_block && end < ex_end) {2883 2884			/*2885			 * If we're going to split the extent, note that2886			 * the cluster containing the block after 'end' is2887			 * in use to avoid freeing it when removing blocks.2888			 */2889			if (sbi->s_cluster_ratio > 1) {2890				pblk = ext4_ext_pblock(ex) + end - ee_block + 1;2891				partial.pclu = EXT4_B2C(sbi, pblk);2892				partial.state = nofree;2893			}2894 2895			/*2896			 * Split the extent in two so that 'end' is the last2897			 * block in the first new extent. Also we should not2898			 * fail removing space due to ENOSPC so try to use2899			 * reserved block if that happens.2900			 */2901			path = ext4_force_split_extent_at(handle, inode, path,2902							  end + 1, 1);2903			if (IS_ERR(path)) {2904				err = PTR_ERR(path);2905				goto out;2906			}2907		} else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&2908			   partial.state == initial) {2909			/*2910			 * If we're punching, there's an extent to the right.2911			 * If the partial cluster hasn't been set, set it to2912			 * that extent's first cluster and its state to nofree2913			 * so it won't be freed should it contain blocks to be2914			 * removed. If it's already set (tofree/nofree), we're2915			 * retrying and keep the original partial cluster info2916			 * so a cluster marked tofree as a result of earlier2917			 * extent removal is not lost.2918			 */2919			lblk = ex_end + 1;2920			err = ext4_ext_search_right(inode, path, &lblk, &pblk,2921						    NULL);2922			if (err < 0)2923				goto out;2924			if (pblk) {2925				partial.pclu = EXT4_B2C(sbi, pblk);2926				partial.state = nofree;2927			}2928		}2929	}2930	/*2931	 * We start scanning from right side, freeing all the blocks2932	 * after i_size and walking into the tree depth-wise.2933	 */2934	depth = ext_depth(inode);2935	if (path) {2936		int k = i = depth;2937		while (--k > 0)2938			path[k].p_block =2939				le16_to_cpu(path[k].p_hdr->eh_entries)+1;2940	} else {2941		path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),2942			       GFP_NOFS | __GFP_NOFAIL);2943		if (path == NULL) {2944			ext4_journal_stop(handle);2945			return -ENOMEM;2946		}2947		path[0].p_maxdepth = path[0].p_depth = depth;2948		path[0].p_hdr = ext_inode_hdr(inode);2949		i = 0;2950 2951		if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {2952			err = -EFSCORRUPTED;2953			goto out;2954		}2955	}2956	err = 0;2957 2958	while (i >= 0 && err == 0) {2959		if (i == depth) {2960			/* this is leaf block */2961			err = ext4_ext_rm_leaf(handle, inode, path,2962					       &partial, start, end);2963			/* root level has p_bh == NULL, brelse() eats this */2964			ext4_ext_path_brelse(path + i);2965			i--;2966			continue;2967		}2968 2969		/* this is index block */2970		if (!path[i].p_hdr) {2971			ext_debug(inode, "initialize header\n");2972			path[i].p_hdr = ext_block_hdr(path[i].p_bh);2973		}2974 2975		if (!path[i].p_idx) {2976			/* this level hasn't been touched yet */2977			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);2978			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;2979			ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",2980				  path[i].p_hdr,2981				  le16_to_cpu(path[i].p_hdr->eh_entries));2982		} else {2983			/* we were already here, see at next index */2984			path[i].p_idx--;2985		}2986 2987		ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",2988				i, EXT_FIRST_INDEX(path[i].p_hdr),2989				path[i].p_idx);2990		if (ext4_ext_more_to_rm(path + i)) {2991			struct buffer_head *bh;2992			/* go to the next level */2993			ext_debug(inode, "move to level %d (block %llu)\n",2994				  i + 1, ext4_idx_pblock(path[i].p_idx));2995			memset(path + i + 1, 0, sizeof(*path));2996			bh = read_extent_tree_block(inode, path[i].p_idx,2997						    depth - i - 1,2998						    EXT4_EX_NOCACHE);2999			if (IS_ERR(bh)) {3000				/* should we reset i_size? */3001				err = PTR_ERR(bh);3002				break;3003			}3004			/* Yield here to deal with large extent trees.3005			 * Should be a no-op if we did IO above. */3006			cond_resched();3007			if (WARN_ON(i + 1 > depth)) {3008				err = -EFSCORRUPTED;3009				break;3010			}3011			path[i + 1].p_bh = bh;3012 3013			/* save actual number of indexes since this3014			 * number is changed at the next iteration */3015			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);3016			i++;3017		} else {3018			/* we finished processing this index, go up */3019			if (path[i].p_hdr->eh_entries == 0 && i > 0) {3020				/* index is empty, remove it;3021				 * handle must be already prepared by the3022				 * truncatei_leaf() */3023				err = ext4_ext_rm_idx(handle, inode, path, i);3024			}3025			/* root level has p_bh == NULL, brelse() eats this */3026			ext4_ext_path_brelse(path + i);3027			i--;3028			ext_debug(inode, "return to level %d\n", i);3029		}3030	}3031 3032	trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,3033					 path->p_hdr->eh_entries);3034 3035	/*3036	 * if there's a partial cluster and we have removed the first extent3037	 * in the file, then we also free the partial cluster, if any3038	 */3039	if (partial.state == tofree && err == 0) {3040		int flags = get_default_free_blocks_flags(inode);3041 3042		if (ext4_is_pending(inode, partial.lblk))3043			flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;3044		ext4_free_blocks(handle, inode, NULL,3045				 EXT4_C2B(sbi, partial.pclu),3046				 sbi->s_cluster_ratio, flags);3047		if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)3048			ext4_rereserve_cluster(inode, partial.lblk);3049		partial.state = initial;3050	}3051 3052	/* TODO: flexible tree reduction should be here */3053	if (path->p_hdr->eh_entries == 0) {3054		/*3055		 * truncate to zero freed all the tree,3056		 * so we need to correct eh_depth3057		 */3058		err = ext4_ext_get_access(handle, inode, path);3059		if (err == 0) {3060			ext_inode_hdr(inode)->eh_depth = 0;3061			ext_inode_hdr(inode)->eh_max =3062				cpu_to_le16(ext4_ext_space_root(inode, 0));3063			err = ext4_ext_dirty(handle, inode, path);3064		}3065	}3066out:3067	ext4_free_ext_path(path);3068	path = NULL;3069	if (err == -EAGAIN)3070		goto again;3071	ext4_journal_stop(handle);3072 3073	return err;3074}3075 3076/*3077 * called at mount time3078 */3079void ext4_ext_init(struct super_block *sb)3080{3081	/*3082	 * possible initialization would be here3083	 */3084 3085	if (ext4_has_feature_extents(sb)) {3086#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)3087		printk(KERN_INFO "EXT4-fs: file extents enabled"3088#ifdef AGGRESSIVE_TEST3089		       ", aggressive tests"3090#endif3091#ifdef CHECK_BINSEARCH3092		       ", check binsearch"3093#endif3094#ifdef EXTENTS_STATS3095		       ", stats"3096#endif3097		       "\n");3098#endif3099#ifdef EXTENTS_STATS3100		spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);3101		EXT4_SB(sb)->s_ext_min = 1 << 30;3102		EXT4_SB(sb)->s_ext_max = 0;3103#endif3104	}3105}3106 3107/*3108 * called at umount time3109 */3110void ext4_ext_release(struct super_block *sb)3111{3112	if (!ext4_has_feature_extents(sb))3113		return;3114 3115#ifdef EXTENTS_STATS3116	if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {3117		struct ext4_sb_info *sbi = EXT4_SB(sb);3118		printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",3119			sbi->s_ext_blocks, sbi->s_ext_extents,3120			sbi->s_ext_blocks / sbi->s_ext_extents);3121		printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",3122			sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);3123	}3124#endif3125}3126 3127static void ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)3128{3129	ext4_lblk_t  ee_block;3130	ext4_fsblk_t ee_pblock;3131	unsigned int ee_len;3132 3133	ee_block  = le32_to_cpu(ex->ee_block);3134	ee_len    = ext4_ext_get_actual_len(ex);3135	ee_pblock = ext4_ext_pblock(ex);3136 3137	if (ee_len == 0)3138		return;3139 3140	ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,3141			      EXTENT_STATUS_WRITTEN, 0);3142}3143 3144/* FIXME!! we need to try to merge to left or right after zero-out  */3145static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)3146{3147	ext4_fsblk_t ee_pblock;3148	unsigned int ee_len;3149 3150	ee_len    = ext4_ext_get_actual_len(ex);3151	ee_pblock = ext4_ext_pblock(ex);3152	return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,3153				  ee_len);3154}3155 3156/*3157 * ext4_split_extent_at() splits an extent at given block.3158 *3159 * @handle: the journal handle3160 * @inode: the file inode3161 * @path: the path to the extent3162 * @split: the logical block where the extent is splitted.3163 * @split_flags: indicates if the extent could be zeroout if split fails, and3164 *		 the states(init or unwritten) of new extents.3165 * @flags: flags used to insert new extent to extent tree.3166 *3167 *3168 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states3169 * of which are determined by split_flag.3170 *3171 * There are two cases:3172 *  a> the extent are splitted into two extent.3173 *  b> split is not needed, and just mark the extent.3174 *3175 * Return an extent path pointer on success, or an error pointer on failure.3176 */3177static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,3178						  struct inode *inode,3179						  struct ext4_ext_path *path,3180						  ext4_lblk_t split,3181						  int split_flag, int flags)3182{3183	ext4_fsblk_t newblock;3184	ext4_lblk_t ee_block;3185	struct ext4_extent *ex, newex, orig_ex, zero_ex;3186	struct ext4_extent *ex2 = NULL;3187	unsigned int ee_len, depth;3188	int err = 0;3189 3190	BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==3191	       (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));3192 3193	ext_debug(inode, "logical block %llu\n", (unsigned long long)split);3194 3195	ext4_ext_show_leaf(inode, path);3196 3197	depth = ext_depth(inode);3198	ex = path[depth].p_ext;3199	ee_block = le32_to_cpu(ex->ee_block);3200	ee_len = ext4_ext_get_actual_len(ex);3201	newblock = split - ee_block + ext4_ext_pblock(ex);3202 3203	BUG_ON(split < ee_block || split >= (ee_block + ee_len));3204	BUG_ON(!ext4_ext_is_unwritten(ex) &&3205	       split_flag & (EXT4_EXT_MAY_ZEROOUT |3206			     EXT4_EXT_MARK_UNWRIT1 |3207			     EXT4_EXT_MARK_UNWRIT2));3208 3209	err = ext4_ext_get_access(handle, inode, path + depth);3210	if (err)3211		goto out;3212 3213	if (split == ee_block) {3214		/*3215		 * case b: block @split is the block that the extent begins with3216		 * then we just change the state of the extent, and splitting3217		 * is not needed.3218		 */3219		if (split_flag & EXT4_EXT_MARK_UNWRIT2)3220			ext4_ext_mark_unwritten(ex);3221		else3222			ext4_ext_mark_initialized(ex);3223 3224		if (!(flags & EXT4_GET_BLOCKS_PRE_IO))3225			ext4_ext_try_to_merge(handle, inode, path, ex);3226 3227		err = ext4_ext_dirty(handle, inode, path + path->p_depth);3228		goto out;3229	}3230 3231	/* case a */3232	memcpy(&orig_ex, ex, sizeof(orig_ex));3233	ex->ee_len = cpu_to_le16(split - ee_block);3234	if (split_flag & EXT4_EXT_MARK_UNWRIT1)3235		ext4_ext_mark_unwritten(ex);3236 3237	/*3238	 * path may lead to new leaf, not to original leaf any more3239	 * after ext4_ext_insert_extent() returns,3240	 */3241	err = ext4_ext_dirty(handle, inode, path + depth);3242	if (err)3243		goto fix_extent_len;3244 3245	ex2 = &newex;3246	ex2->ee_block = cpu_to_le32(split);3247	ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));3248	ext4_ext_store_pblock(ex2, newblock);3249	if (split_flag & EXT4_EXT_MARK_UNWRIT2)3250		ext4_ext_mark_unwritten(ex2);3251 3252	path = ext4_ext_insert_extent(handle, inode, path, &newex, flags);3253	if (!IS_ERR(path))3254		goto out;3255 3256	err = PTR_ERR(path);3257	if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)3258		return path;3259 3260	/*3261	 * Get a new path to try to zeroout or fix the extent length.3262	 * Using EXT4_EX_NOFAIL guarantees that ext4_find_extent()3263	 * will not return -ENOMEM, otherwise -ENOMEM will cause a3264	 * retry in do_writepages(), and a WARN_ON may be triggered3265	 * in ext4_da_update_reserve_space() due to an incorrect3266	 * ee_len causing the i_reserved_data_blocks exception.3267	 */3268	path = ext4_find_extent(inode, ee_block, NULL, flags | EXT4_EX_NOFAIL);3269	if (IS_ERR(path)) {3270		EXT4_ERROR_INODE(inode, "Failed split extent on %u, err %ld",3271				 split, PTR_ERR(path));3272		return path;3273	}3274	depth = ext_depth(inode);3275	ex = path[depth].p_ext;3276 3277	if (EXT4_EXT_MAY_ZEROOUT & split_flag) {3278		if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {3279			if (split_flag & EXT4_EXT_DATA_VALID1) {3280				err = ext4_ext_zeroout(inode, ex2);3281				zero_ex.ee_block = ex2->ee_block;3282				zero_ex.ee_len = cpu_to_le16(3283						ext4_ext_get_actual_len(ex2));3284				ext4_ext_store_pblock(&zero_ex,3285						      ext4_ext_pblock(ex2));3286			} else {3287				err = ext4_ext_zeroout(inode, ex);3288				zero_ex.ee_block = ex->ee_block;3289				zero_ex.ee_len = cpu_to_le16(3290						ext4_ext_get_actual_len(ex));3291				ext4_ext_store_pblock(&zero_ex,3292						      ext4_ext_pblock(ex));3293			}3294		} else {3295			err = ext4_ext_zeroout(inode, &orig_ex);3296			zero_ex.ee_block = orig_ex.ee_block;3297			zero_ex.ee_len = cpu_to_le16(3298						ext4_ext_get_actual_len(&orig_ex));3299			ext4_ext_store_pblock(&zero_ex,3300					      ext4_ext_pblock(&orig_ex));3301		}3302 3303		if (!err) {3304			/* update the extent length and mark as initialized */3305			ex->ee_len = cpu_to_le16(ee_len);3306			ext4_ext_try_to_merge(handle, inode, path, ex);3307			err = ext4_ext_dirty(handle, inode, path + path->p_depth);3308			if (!err)3309				/* update extent status tree */3310				ext4_zeroout_es(inode, &zero_ex);3311			/* If we failed at this point, we don't know in which3312			 * state the extent tree exactly is so don't try to fix3313			 * length of the original extent as it may do even more3314			 * damage.3315			 */3316			goto out;3317		}3318	}3319 3320fix_extent_len:3321	ex->ee_len = orig_ex.ee_len;3322	/*3323	 * Ignore ext4_ext_dirty return value since we are already in error path3324	 * and err is a non-zero error code.3325	 */3326	ext4_ext_dirty(handle, inode, path + path->p_depth);3327out:3328	if (err) {3329		ext4_free_ext_path(path);3330		path = ERR_PTR(err);3331	}3332	ext4_ext_show_leaf(inode, path);3333	return path;3334}3335 3336/*3337 * ext4_split_extent() splits an extent and mark extent which is covered3338 * by @map as split_flags indicates3339 *3340 * It may result in splitting the extent into multiple extents (up to three)3341 * There are three possibilities:3342 *   a> There is no split required3343 *   b> Splits in two extents: Split is happening at either end of the extent3344 *   c> Splits in three extents: Somone is splitting in middle of the extent3345 *3346 */3347static struct ext4_ext_path *ext4_split_extent(handle_t *handle,3348					       struct inode *inode,3349					       struct ext4_ext_path *path,3350					       struct ext4_map_blocks *map,3351					       int split_flag, int flags,3352					       unsigned int *allocated)3353{3354	ext4_lblk_t ee_block;3355	struct ext4_extent *ex;3356	unsigned int ee_len, depth;3357	int unwritten;3358	int split_flag1, flags1;3359 3360	depth = ext_depth(inode);3361	ex = path[depth].p_ext;3362	ee_block = le32_to_cpu(ex->ee_block);3363	ee_len = ext4_ext_get_actual_len(ex);3364	unwritten = ext4_ext_is_unwritten(ex);3365 3366	if (map->m_lblk + map->m_len < ee_block + ee_len) {3367		split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;3368		flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;3369		if (unwritten)3370			split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |3371				       EXT4_EXT_MARK_UNWRIT2;3372		if (split_flag & EXT4_EXT_DATA_VALID2)3373			split_flag1 |= EXT4_EXT_DATA_VALID1;3374		path = ext4_split_extent_at(handle, inode, path,3375				map->m_lblk + map->m_len, split_flag1, flags1);3376		if (IS_ERR(path))3377			return path;3378		/*3379		 * Update path is required because previous ext4_split_extent_at3380		 * may result in split of original leaf or extent zeroout.3381		 */3382		path = ext4_find_extent(inode, map->m_lblk, path, flags);3383		if (IS_ERR(path))3384			return path;3385		depth = ext_depth(inode);3386		ex = path[depth].p_ext;3387		if (!ex) {3388			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",3389					(unsigned long) map->m_lblk);3390			ext4_free_ext_path(path);3391			return ERR_PTR(-EFSCORRUPTED);3392		}3393		unwritten = ext4_ext_is_unwritten(ex);3394	}3395 3396	if (map->m_lblk >= ee_block) {3397		split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;3398		if (unwritten) {3399			split_flag1 |= EXT4_EXT_MARK_UNWRIT1;3400			split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |3401						     EXT4_EXT_MARK_UNWRIT2);3402		}3403		path = ext4_split_extent_at(handle, inode, path,3404				map->m_lblk, split_flag1, flags);3405		if (IS_ERR(path))3406			return path;3407	}3408 3409	if (allocated) {3410		if (map->m_lblk + map->m_len > ee_block + ee_len)3411			*allocated = ee_len - (map->m_lblk - ee_block);3412		else3413			*allocated = map->m_len;3414	}3415	ext4_ext_show_leaf(inode, path);3416	return path;3417}3418 3419/*3420 * This function is called by ext4_ext_map_blocks() if someone tries to write3421 * to an unwritten extent. It may result in splitting the unwritten3422 * extent into multiple extents (up to three - one initialized and two3423 * unwritten).3424 * There are three possibilities:3425 *   a> There is no split required: Entire extent should be initialized3426 *   b> Splits in two extents: Write is happening at either end of the extent3427 *   c> Splits in three extents: Somone is writing in middle of the extent3428 *3429 * Pre-conditions:3430 *  - The extent pointed to by 'path' is unwritten.3431 *  - The extent pointed to by 'path' contains a superset3432 *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).3433 *3434 * Post-conditions on success:3435 *  - the returned value is the number of blocks beyond map->l_lblk3436 *    that are allocated and initialized.3437 *    It is guaranteed to be >= map->m_len.3438 */3439static struct ext4_ext_path *3440ext4_ext_convert_to_initialized(handle_t *handle, struct inode *inode,3441			struct ext4_map_blocks *map, struct ext4_ext_path *path,3442			int flags, unsigned int *allocated)3443{3444	struct ext4_sb_info *sbi;3445	struct ext4_extent_header *eh;3446	struct ext4_map_blocks split_map;3447	struct ext4_extent zero_ex1, zero_ex2;3448	struct ext4_extent *ex, *abut_ex;3449	ext4_lblk_t ee_block, eof_block;3450	unsigned int ee_len, depth, map_len = map->m_len;3451	int err = 0;3452	int split_flag = EXT4_EXT_DATA_VALID2;3453	unsigned int max_zeroout = 0;3454 3455	ext_debug(inode, "logical block %llu, max_blocks %u\n",3456		  (unsigned long long)map->m_lblk, map_len);3457 3458	sbi = EXT4_SB(inode->i_sb);3459	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)3460			>> inode->i_sb->s_blocksize_bits;3461	if (eof_block < map->m_lblk + map_len)3462		eof_block = map->m_lblk + map_len;3463 3464	depth = ext_depth(inode);3465	eh = path[depth].p_hdr;3466	ex = path[depth].p_ext;3467	ee_block = le32_to_cpu(ex->ee_block);3468	ee_len = ext4_ext_get_actual_len(ex);3469	zero_ex1.ee_len = 0;3470	zero_ex2.ee_len = 0;3471 3472	trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);3473 3474	/* Pre-conditions */3475	BUG_ON(!ext4_ext_is_unwritten(ex));3476	BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));3477 3478	/*3479	 * Attempt to transfer newly initialized blocks from the currently3480	 * unwritten extent to its neighbor. This is much cheaper3481	 * than an insertion followed by a merge as those involve costly3482	 * memmove() calls. Transferring to the left is the common case in3483	 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)3484	 * followed by append writes.3485	 *3486	 * Limitations of the current logic:3487	 *  - L1: we do not deal with writes covering the whole extent.3488	 *    This would require removing the extent if the transfer3489	 *    is possible.3490	 *  - L2: we only attempt to merge with an extent stored in the3491	 *    same extent tree node.3492	 */3493	*allocated = 0;3494	if ((map->m_lblk == ee_block) &&3495		/* See if we can merge left */3496		(map_len < ee_len) &&		/*L1*/3497		(ex > EXT_FIRST_EXTENT(eh))) {	/*L2*/3498		ext4_lblk_t prev_lblk;3499		ext4_fsblk_t prev_pblk, ee_pblk;3500		unsigned int prev_len;3501 3502		abut_ex = ex - 1;3503		prev_lblk = le32_to_cpu(abut_ex->ee_block);3504		prev_len = ext4_ext_get_actual_len(abut_ex);3505		prev_pblk = ext4_ext_pblock(abut_ex);3506		ee_pblk = ext4_ext_pblock(ex);3507 3508		/*3509		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed3510		 * upon those conditions:3511		 * - C1: abut_ex is initialized,3512		 * - C2: abut_ex is logically abutting ex,3513		 * - C3: abut_ex is physically abutting ex,3514		 * - C4: abut_ex can receive the additional blocks without3515		 *   overflowing the (initialized) length limit.3516		 */3517		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/3518			((prev_lblk + prev_len) == ee_block) &&		/*C2*/3519			((prev_pblk + prev_len) == ee_pblk) &&		/*C3*/3520			(prev_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/3521			err = ext4_ext_get_access(handle, inode, path + depth);3522			if (err)3523				goto errout;3524 3525			trace_ext4_ext_convert_to_initialized_fastpath(inode,3526				map, ex, abut_ex);3527 3528			/* Shift the start of ex by 'map_len' blocks */3529			ex->ee_block = cpu_to_le32(ee_block + map_len);3530			ext4_ext_store_pblock(ex, ee_pblk + map_len);3531			ex->ee_len = cpu_to_le16(ee_len - map_len);3532			ext4_ext_mark_unwritten(ex); /* Restore the flag */3533 3534			/* Extend abut_ex by 'map_len' blocks */3535			abut_ex->ee_len = cpu_to_le16(prev_len + map_len);3536 3537			/* Result: number of initialized blocks past m_lblk */3538			*allocated = map_len;3539		}3540	} else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&3541		   (map_len < ee_len) &&	/*L1*/3542		   ex < EXT_LAST_EXTENT(eh)) {	/*L2*/3543		/* See if we can merge right */3544		ext4_lblk_t next_lblk;3545		ext4_fsblk_t next_pblk, ee_pblk;3546		unsigned int next_len;3547 3548		abut_ex = ex + 1;3549		next_lblk = le32_to_cpu(abut_ex->ee_block);3550		next_len = ext4_ext_get_actual_len(abut_ex);3551		next_pblk = ext4_ext_pblock(abut_ex);3552		ee_pblk = ext4_ext_pblock(ex);3553 3554		/*3555		 * A transfer of blocks from 'ex' to 'abut_ex' is allowed3556		 * upon those conditions:3557		 * - C1: abut_ex is initialized,3558		 * - C2: abut_ex is logically abutting ex,3559		 * - C3: abut_ex is physically abutting ex,3560		 * - C4: abut_ex can receive the additional blocks without3561		 *   overflowing the (initialized) length limit.3562		 */3563		if ((!ext4_ext_is_unwritten(abut_ex)) &&		/*C1*/3564		    ((map->m_lblk + map_len) == next_lblk) &&		/*C2*/3565		    ((ee_pblk + ee_len) == next_pblk) &&		/*C3*/3566		    (next_len < (EXT_INIT_MAX_LEN - map_len))) {	/*C4*/3567			err = ext4_ext_get_access(handle, inode, path + depth);3568			if (err)3569				goto errout;3570 3571			trace_ext4_ext_convert_to_initialized_fastpath(inode,3572				map, ex, abut_ex);3573 3574			/* Shift the start of abut_ex by 'map_len' blocks */3575			abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);3576			ext4_ext_store_pblock(abut_ex, next_pblk - map_len);3577			ex->ee_len = cpu_to_le16(ee_len - map_len);3578			ext4_ext_mark_unwritten(ex); /* Restore the flag */3579 3580			/* Extend abut_ex by 'map_len' blocks */3581			abut_ex->ee_len = cpu_to_le16(next_len + map_len);3582 3583			/* Result: number of initialized blocks past m_lblk */3584			*allocated = map_len;3585		}3586	}3587	if (*allocated) {3588		/* Mark the block containing both extents as dirty */3589		err = ext4_ext_dirty(handle, inode, path + depth);3590 3591		/* Update path to point to the right extent */3592		path[depth].p_ext = abut_ex;3593		if (err)3594			goto errout;3595		goto out;3596	} else3597		*allocated = ee_len - (map->m_lblk - ee_block);3598 3599	WARN_ON(map->m_lblk < ee_block);3600	/*3601	 * It is safe to convert extent to initialized via explicit3602	 * zeroout only if extent is fully inside i_size or new_size.3603	 */3604	split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;3605 3606	if (EXT4_EXT_MAY_ZEROOUT & split_flag)3607		max_zeroout = sbi->s_extent_max_zeroout_kb >>3608			(inode->i_sb->s_blocksize_bits - 10);3609 3610	/*3611	 * five cases:3612	 * 1. split the extent into three extents.3613	 * 2. split the extent into two extents, zeroout the head of the first3614	 *    extent.3615	 * 3. split the extent into two extents, zeroout the tail of the second3616	 *    extent.3617	 * 4. split the extent into two extents with out zeroout.3618	 * 5. no splitting needed, just possibly zeroout the head and / or the3619	 *    tail of the extent.3620	 */3621	split_map.m_lblk = map->m_lblk;3622	split_map.m_len = map->m_len;3623 3624	if (max_zeroout && (*allocated > split_map.m_len)) {3625		if (*allocated <= max_zeroout) {3626			/* case 3 or 5 */3627			zero_ex1.ee_block =3628				 cpu_to_le32(split_map.m_lblk +3629					     split_map.m_len);3630			zero_ex1.ee_len =3631				cpu_to_le16(*allocated - split_map.m_len);3632			ext4_ext_store_pblock(&zero_ex1,3633				ext4_ext_pblock(ex) + split_map.m_lblk +3634				split_map.m_len - ee_block);3635			err = ext4_ext_zeroout(inode, &zero_ex1);3636			if (err)3637				goto fallback;3638			split_map.m_len = *allocated;3639		}3640		if (split_map.m_lblk - ee_block + split_map.m_len <3641								max_zeroout) {3642			/* case 2 or 5 */3643			if (split_map.m_lblk != ee_block) {3644				zero_ex2.ee_block = ex->ee_block;3645				zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -3646							ee_block);3647				ext4_ext_store_pblock(&zero_ex2,3648						      ext4_ext_pblock(ex));3649				err = ext4_ext_zeroout(inode, &zero_ex2);3650				if (err)3651					goto fallback;3652			}3653 3654			split_map.m_len += split_map.m_lblk - ee_block;3655			split_map.m_lblk = ee_block;3656			*allocated = map->m_len;3657		}3658	}3659 3660fallback:3661	path = ext4_split_extent(handle, inode, path, &split_map, split_flag,3662				 flags, NULL);3663	if (IS_ERR(path))3664		return path;3665out:3666	/* If we have gotten a failure, don't zero out status tree */3667	ext4_zeroout_es(inode, &zero_ex1);3668	ext4_zeroout_es(inode, &zero_ex2);3669	return path;3670 3671errout:3672	ext4_free_ext_path(path);3673	return ERR_PTR(err);3674}3675 3676/*3677 * This function is called by ext4_ext_map_blocks() from3678 * ext4_get_blocks_dio_write() when DIO to write3679 * to an unwritten extent.3680 *3681 * Writing to an unwritten extent may result in splitting the unwritten3682 * extent into multiple initialized/unwritten extents (up to three)3683 * There are three possibilities:3684 *   a> There is no split required: Entire extent should be unwritten3685 *   b> Splits in two extents: Write is happening at either end of the extent3686 *   c> Splits in three extents: Somone is writing in middle of the extent3687 *3688 * This works the same way in the case of initialized -> unwritten conversion.3689 *3690 * One of more index blocks maybe needed if the extent tree grow after3691 * the unwritten extent split. To prevent ENOSPC occur at the IO3692 * complete, we need to split the unwritten extent before DIO submit3693 * the IO. The unwritten extent called at this time will be split3694 * into three unwritten extent(at most). After IO complete, the part3695 * being filled will be convert to initialized by the end_io callback function3696 * via ext4_convert_unwritten_extents().3697 *3698 * The size of unwritten extent to be written is passed to the caller via the3699 * allocated pointer. Return an extent path pointer on success, or an error3700 * pointer on failure.3701 */3702static struct ext4_ext_path *ext4_split_convert_extents(handle_t *handle,3703					struct inode *inode,3704					struct ext4_map_blocks *map,3705					struct ext4_ext_path *path,3706					int flags, unsigned int *allocated)3707{3708	ext4_lblk_t eof_block;3709	ext4_lblk_t ee_block;3710	struct ext4_extent *ex;3711	unsigned int ee_len;3712	int split_flag = 0, depth;3713 3714	ext_debug(inode, "logical block %llu, max_blocks %u\n",3715		  (unsigned long long)map->m_lblk, map->m_len);3716 3717	eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)3718			>> inode->i_sb->s_blocksize_bits;3719	if (eof_block < map->m_lblk + map->m_len)3720		eof_block = map->m_lblk + map->m_len;3721	/*3722	 * It is safe to convert extent to initialized via explicit3723	 * zeroout only if extent is fully inside i_size or new_size.3724	 */3725	depth = ext_depth(inode);3726	ex = path[depth].p_ext;3727	ee_block = le32_to_cpu(ex->ee_block);3728	ee_len = ext4_ext_get_actual_len(ex);3729 3730	/* Convert to unwritten */3731	if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {3732		split_flag |= EXT4_EXT_DATA_VALID1;3733	/* Convert to initialized */3734	} else if (flags & EXT4_GET_BLOCKS_CONVERT) {3735		split_flag |= ee_block + ee_len <= eof_block ?3736			      EXT4_EXT_MAY_ZEROOUT : 0;3737		split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);3738	}3739	flags |= EXT4_GET_BLOCKS_PRE_IO;3740	return ext4_split_extent(handle, inode, path, map, split_flag, flags,3741				 allocated);3742}3743 3744static struct ext4_ext_path *3745ext4_convert_unwritten_extents_endio(handle_t *handle, struct inode *inode,3746				     struct ext4_map_blocks *map,3747				     struct ext4_ext_path *path)3748{3749	struct ext4_extent *ex;3750	ext4_lblk_t ee_block;3751	unsigned int ee_len;3752	int depth;3753	int err = 0;3754 3755	depth = ext_depth(inode);3756	ex = path[depth].p_ext;3757	ee_block = le32_to_cpu(ex->ee_block);3758	ee_len = ext4_ext_get_actual_len(ex);3759 3760	ext_debug(inode, "logical block %llu, max_blocks %u\n",3761		  (unsigned long long)ee_block, ee_len);3762 3763	/* If extent is larger than requested it is a clear sign that we still3764	 * have some extent state machine issues left. So extent_split is still3765	 * required.3766	 * TODO: Once all related issues will be fixed this situation should be3767	 * illegal.3768	 */3769	if (ee_block != map->m_lblk || ee_len > map->m_len) {3770#ifdef CONFIG_EXT4_DEBUG3771		ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"3772			     " len %u; IO logical block %llu, len %u",3773			     inode->i_ino, (unsigned long long)ee_block, ee_len,3774			     (unsigned long long)map->m_lblk, map->m_len);3775#endif3776		path = ext4_split_convert_extents(handle, inode, map, path,3777						EXT4_GET_BLOCKS_CONVERT, NULL);3778		if (IS_ERR(path))3779			return path;3780 3781		path = ext4_find_extent(inode, map->m_lblk, path, 0);3782		if (IS_ERR(path))3783			return path;3784		depth = ext_depth(inode);3785		ex = path[depth].p_ext;3786	}3787 3788	err = ext4_ext_get_access(handle, inode, path + depth);3789	if (err)3790		goto errout;3791	/* first mark the extent as initialized */3792	ext4_ext_mark_initialized(ex);3793 3794	/* note: ext4_ext_correct_indexes() isn't needed here because3795	 * borders are not changed3796	 */3797	ext4_ext_try_to_merge(handle, inode, path, ex);3798 3799	/* Mark modified extent as dirty */3800	err = ext4_ext_dirty(handle, inode, path + path->p_depth);3801	if (err)3802		goto errout;3803 3804	ext4_ext_show_leaf(inode, path);3805	return path;3806 3807errout:3808	ext4_free_ext_path(path);3809	return ERR_PTR(err);3810}3811 3812static struct ext4_ext_path *3813convert_initialized_extent(handle_t *handle, struct inode *inode,3814			   struct ext4_map_blocks *map,3815			   struct ext4_ext_path *path,3816			   unsigned int *allocated)3817{3818	struct ext4_extent *ex;3819	ext4_lblk_t ee_block;3820	unsigned int ee_len;3821	int depth;3822	int err = 0;3823 3824	/*3825	 * Make sure that the extent is no bigger than we support with3826	 * unwritten extent3827	 */3828	if (map->m_len > EXT_UNWRITTEN_MAX_LEN)3829		map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;3830 3831	depth = ext_depth(inode);3832	ex = path[depth].p_ext;3833	ee_block = le32_to_cpu(ex->ee_block);3834	ee_len = ext4_ext_get_actual_len(ex);3835 3836	ext_debug(inode, "logical block %llu, max_blocks %u\n",3837		  (unsigned long long)ee_block, ee_len);3838 3839	if (ee_block != map->m_lblk || ee_len > map->m_len) {3840		path = ext4_split_convert_extents(handle, inode, map, path,3841				EXT4_GET_BLOCKS_CONVERT_UNWRITTEN, NULL);3842		if (IS_ERR(path))3843			return path;3844 3845		path = ext4_find_extent(inode, map->m_lblk, path, 0);3846		if (IS_ERR(path))3847			return path;3848		depth = ext_depth(inode);3849		ex = path[depth].p_ext;3850		if (!ex) {3851			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",3852					 (unsigned long) map->m_lblk);3853			err = -EFSCORRUPTED;3854			goto errout;3855		}3856	}3857 3858	err = ext4_ext_get_access(handle, inode, path + depth);3859	if (err)3860		goto errout;3861	/* first mark the extent as unwritten */3862	ext4_ext_mark_unwritten(ex);3863 3864	/* note: ext4_ext_correct_indexes() isn't needed here because3865	 * borders are not changed3866	 */3867	ext4_ext_try_to_merge(handle, inode, path, ex);3868 3869	/* Mark modified extent as dirty */3870	err = ext4_ext_dirty(handle, inode, path + path->p_depth);3871	if (err)3872		goto errout;3873	ext4_ext_show_leaf(inode, path);3874 3875	ext4_update_inode_fsync_trans(handle, inode, 1);3876 3877	map->m_flags |= EXT4_MAP_UNWRITTEN;3878	if (*allocated > map->m_len)3879		*allocated = map->m_len;3880	map->m_len = *allocated;3881	return path;3882 3883errout:3884	ext4_free_ext_path(path);3885	return ERR_PTR(err);3886}3887 3888static struct ext4_ext_path *3889ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,3890			struct ext4_map_blocks *map,3891			struct ext4_ext_path *path, int flags,3892			unsigned int *allocated, ext4_fsblk_t newblock)3893{3894	int err = 0;3895 3896	ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n",3897		  (unsigned long long)map->m_lblk, map->m_len, flags,3898		  *allocated);3899	ext4_ext_show_leaf(inode, path);3900 3901	/*3902	 * When writing into unwritten space, we should not fail to3903	 * allocate metadata blocks for the new extent block if needed.3904	 */3905	flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;3906 3907	trace_ext4_ext_handle_unwritten_extents(inode, map, flags,3908						*allocated, newblock);3909 3910	/* get_block() before submitting IO, split the extent */3911	if (flags & EXT4_GET_BLOCKS_PRE_IO) {3912		path = ext4_split_convert_extents(handle, inode, map, path,3913				flags | EXT4_GET_BLOCKS_CONVERT, allocated);3914		if (IS_ERR(path))3915			return path;3916		/*3917		 * shouldn't get a 0 allocated when splitting an extent unless3918		 * m_len is 0 (bug) or extent has been corrupted3919		 */3920		if (unlikely(*allocated == 0)) {3921			EXT4_ERROR_INODE(inode,3922					 "unexpected allocated == 0, m_len = %u",3923					 map->m_len);3924			err = -EFSCORRUPTED;3925			goto errout;3926		}3927		map->m_flags |= EXT4_MAP_UNWRITTEN;3928		goto out;3929	}3930	/* IO end_io complete, convert the filled extent to written */3931	if (flags & EXT4_GET_BLOCKS_CONVERT) {3932		path = ext4_convert_unwritten_extents_endio(handle, inode,3933							    map, path);3934		if (IS_ERR(path))3935			return path;3936		ext4_update_inode_fsync_trans(handle, inode, 1);3937		goto map_out;3938	}3939	/* buffered IO cases */3940	/*3941	 * repeat fallocate creation request3942	 * we already have an unwritten extent3943	 */3944	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {3945		map->m_flags |= EXT4_MAP_UNWRITTEN;3946		goto map_out;3947	}3948 3949	/* buffered READ or buffered write_begin() lookup */3950	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {3951		/*3952		 * We have blocks reserved already.  We3953		 * return allocated blocks so that delalloc3954		 * won't do block reservation for us.  But3955		 * the buffer head will be unmapped so that3956		 * a read from the block returns 0s.3957		 */3958		map->m_flags |= EXT4_MAP_UNWRITTEN;3959		goto out1;3960	}3961 3962	/*3963	 * Default case when (flags & EXT4_GET_BLOCKS_CREATE) == 1.3964	 * For buffered writes, at writepage time, etc.  Convert a3965	 * discovered unwritten extent to written.3966	 */3967	path = ext4_ext_convert_to_initialized(handle, inode, map, path,3968					       flags, allocated);3969	if (IS_ERR(path))3970		return path;3971	ext4_update_inode_fsync_trans(handle, inode, 1);3972	/*3973	 * shouldn't get a 0 allocated when converting an unwritten extent3974	 * unless m_len is 0 (bug) or extent has been corrupted3975	 */3976	if (unlikely(*allocated == 0)) {3977		EXT4_ERROR_INODE(inode, "unexpected allocated == 0, m_len = %u",3978				 map->m_len);3979		err = -EFSCORRUPTED;3980		goto errout;3981	}3982 3983out:3984	map->m_flags |= EXT4_MAP_NEW;3985map_out:3986	map->m_flags |= EXT4_MAP_MAPPED;3987out1:3988	map->m_pblk = newblock;3989	if (*allocated > map->m_len)3990		*allocated = map->m_len;3991	map->m_len = *allocated;3992	ext4_ext_show_leaf(inode, path);3993	return path;3994 3995errout:3996	ext4_free_ext_path(path);3997	return ERR_PTR(err);3998}3999 4000/*4001 * get_implied_cluster_alloc - check to see if the requested4002 * allocation (in the map structure) overlaps with a cluster already4003 * allocated in an extent.4004 *	@sb	The filesystem superblock structure4005 *	@map	The requested lblk->pblk mapping4006 *	@ex	The extent structure which might contain an implied4007 *			cluster allocation4008 *4009 * This function is called by ext4_ext_map_blocks() after we failed to4010 * find blocks that were already in the inode's extent tree.  Hence,4011 * we know that the beginning of the requested region cannot overlap4012 * the extent from the inode's extent tree.  There are three cases we4013 * want to catch.  The first is this case:4014 *4015 *		 |--- cluster # N--|4016 *    |--- extent ---|	|---- requested region ---|4017 *			|==========|4018 *4019 * The second case that we need to test for is this one:4020 *4021 *   |--------- cluster # N ----------------|4022 *	   |--- requested region --|   |------- extent ----|4023 *	   |=======================|4024 *4025 * The third case is when the requested region lies between two extents4026 * within the same cluster:4027 *          |------------- cluster # N-------------|4028 * |----- ex -----|                  |---- ex_right ----|4029 *                  |------ requested region ------|4030 *                  |================|4031 *4032 * In each of the above cases, we need to set the map->m_pblk and4033 * map->m_len so it corresponds to the return the extent labelled as4034 * "|====|" from cluster #N, since it is already in use for data in4035 * cluster EXT4_B2C(sbi, map->m_lblk).	We will then return 1 to4036 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated4037 * as a new "allocated" block region.  Otherwise, we will return 0 and4038 * ext4_ext_map_blocks() will then allocate one or more new clusters4039 * by calling ext4_mb_new_blocks().4040 */4041static int get_implied_cluster_alloc(struct super_block *sb,4042				     struct ext4_map_blocks *map,4043				     struct ext4_extent *ex,4044				     struct ext4_ext_path *path)4045{4046	struct ext4_sb_info *sbi = EXT4_SB(sb);4047	ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);4048	ext4_lblk_t ex_cluster_start, ex_cluster_end;4049	ext4_lblk_t rr_cluster_start;4050	ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);4051	ext4_fsblk_t ee_start = ext4_ext_pblock(ex);4052	unsigned short ee_len = ext4_ext_get_actual_len(ex);4053 4054	/* The extent passed in that we are trying to match */4055	ex_cluster_start = EXT4_B2C(sbi, ee_block);4056	ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);4057 4058	/* The requested region passed into ext4_map_blocks() */4059	rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);4060 4061	if ((rr_cluster_start == ex_cluster_end) ||4062	    (rr_cluster_start == ex_cluster_start)) {4063		if (rr_cluster_start == ex_cluster_end)4064			ee_start += ee_len - 1;4065		map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;4066		map->m_len = min(map->m_len,4067				 (unsigned) sbi->s_cluster_ratio - c_offset);4068		/*4069		 * Check for and handle this case:4070		 *4071		 *   |--------- cluster # N-------------|4072		 *		       |------- extent ----|4073		 *	   |--- requested region ---|4074		 *	   |===========|4075		 */4076 4077		if (map->m_lblk < ee_block)4078			map->m_len = min(map->m_len, ee_block - map->m_lblk);4079 4080		/*4081		 * Check for the case where there is already another allocated4082		 * block to the right of 'ex' but before the end of the cluster.4083		 *4084		 *          |------------- cluster # N-------------|4085		 * |----- ex -----|                  |---- ex_right ----|4086		 *                  |------ requested region ------|4087		 *                  |================|4088		 */4089		if (map->m_lblk > ee_block) {4090			ext4_lblk_t next = ext4_ext_next_allocated_block(path);4091			map->m_len = min(map->m_len, next - map->m_lblk);4092		}4093 4094		trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);4095		return 1;4096	}4097 4098	trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);4099	return 0;4100}4101 4102/*4103 * Determine hole length around the given logical block, first try to4104 * locate and expand the hole from the given @path, and then adjust it4105 * if it's partially or completely converted to delayed extents, insert4106 * it into the extent cache tree if it's indeed a hole, finally return4107 * the length of the determined extent.4108 */4109static ext4_lblk_t ext4_ext_determine_insert_hole(struct inode *inode,4110						  struct ext4_ext_path *path,4111						  ext4_lblk_t lblk)4112{4113	ext4_lblk_t hole_start, len;4114	struct extent_status es;4115 4116	hole_start = lblk;4117	len = ext4_ext_find_hole(inode, path, &hole_start);4118again:4119	ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,4120				  hole_start + len - 1, &es);4121	if (!es.es_len)4122		goto insert_hole;4123 4124	/*4125	 * There's a delalloc extent in the hole, handle it if the delalloc4126	 * extent is in front of, behind and straddle the queried range.4127	 */4128	if (lblk >= es.es_lblk + es.es_len) {4129		/*4130		 * The delalloc extent is in front of the queried range,4131		 * find again from the queried start block.4132		 */4133		len -= lblk - hole_start;4134		hole_start = lblk;4135		goto again;4136	} else if (in_range(lblk, es.es_lblk, es.es_len)) {4137		/*4138		 * The delalloc extent containing lblk, it must have been4139		 * added after ext4_map_blocks() checked the extent status4140		 * tree so we are not holding i_rwsem and delalloc info is4141		 * only stabilized by i_data_sem we are going to release4142		 * soon. Don't modify the extent status tree and report4143		 * extent as a hole, just adjust the length to the delalloc4144		 * extent's after lblk.4145		 */4146		len = es.es_lblk + es.es_len - lblk;4147		return len;4148	} else {4149		/*4150		 * The delalloc extent is partially or completely behind4151		 * the queried range, update hole length until the4152		 * beginning of the delalloc extent.4153		 */4154		len = min(es.es_lblk - hole_start, len);4155	}4156 4157insert_hole:4158	/* Put just found gap into cache to speed up subsequent requests */4159	ext_debug(inode, " -> %u:%u\n", hole_start, len);4160	ext4_es_insert_extent(inode, hole_start, len, ~0,4161			      EXTENT_STATUS_HOLE, 0);4162 4163	/* Update hole_len to reflect hole size after lblk */4164	if (hole_start != lblk)4165		len -= lblk - hole_start;4166 4167	return len;4168}4169 4170/*4171 * Block allocation/map/preallocation routine for extents based files4172 *4173 *4174 * Need to be called with4175 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block4176 * (ie, flags is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)4177 *4178 * return > 0, number of blocks already mapped/allocated4179 *          if flags doesn't contain EXT4_GET_BLOCKS_CREATE and these are pre-allocated blocks4180 *          	buffer head is unmapped4181 *          otherwise blocks are mapped4182 *4183 * return = 0, if plain look up failed (blocks have not been allocated)4184 *          buffer head is unmapped4185 *4186 * return < 0, error case.4187 */4188int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,4189			struct ext4_map_blocks *map, int flags)4190{4191	struct ext4_ext_path *path = NULL;4192	struct ext4_extent newex, *ex, ex2;4193	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);4194	ext4_fsblk_t newblock = 0, pblk;4195	int err = 0, depth;4196	unsigned int allocated = 0, offset = 0;4197	unsigned int allocated_clusters = 0;4198	struct ext4_allocation_request ar;4199	ext4_lblk_t cluster_offset;4200 4201	ext_debug(inode, "blocks %u/%u requested\n", map->m_lblk, map->m_len);4202	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);4203 4204	/* find extent for this block */4205	path = ext4_find_extent(inode, map->m_lblk, NULL, 0);4206	if (IS_ERR(path)) {4207		err = PTR_ERR(path);4208		goto out;4209	}4210 4211	depth = ext_depth(inode);4212 4213	/*4214	 * consistent leaf must not be empty;4215	 * this situation is possible, though, _during_ tree modification;4216	 * this is why assert can't be put in ext4_find_extent()4217	 */4218	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {4219		EXT4_ERROR_INODE(inode, "bad extent address "4220				 "lblock: %lu, depth: %d pblock %lld",4221				 (unsigned long) map->m_lblk, depth,4222				 path[depth].p_block);4223		err = -EFSCORRUPTED;4224		goto out;4225	}4226 4227	ex = path[depth].p_ext;4228	if (ex) {4229		ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);4230		ext4_fsblk_t ee_start = ext4_ext_pblock(ex);4231		unsigned short ee_len;4232 4233 4234		/*4235		 * unwritten extents are treated as holes, except that4236		 * we split out initialized portions during a write.4237		 */4238		ee_len = ext4_ext_get_actual_len(ex);4239 4240		trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);4241 4242		/* if found extent covers block, simply return it */4243		if (in_range(map->m_lblk, ee_block, ee_len)) {4244			newblock = map->m_lblk - ee_block + ee_start;4245			/* number of remaining blocks in the extent */4246			allocated = ee_len - (map->m_lblk - ee_block);4247			ext_debug(inode, "%u fit into %u:%d -> %llu\n",4248				  map->m_lblk, ee_block, ee_len, newblock);4249 4250			/*4251			 * If the extent is initialized check whether the4252			 * caller wants to convert it to unwritten.4253			 */4254			if ((!ext4_ext_is_unwritten(ex)) &&4255			    (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {4256				path = convert_initialized_extent(handle,4257					inode, map, path, &allocated);4258				if (IS_ERR(path))4259					err = PTR_ERR(path);4260				goto out;4261			} else if (!ext4_ext_is_unwritten(ex)) {4262				map->m_flags |= EXT4_MAP_MAPPED;4263				map->m_pblk = newblock;4264				if (allocated > map->m_len)4265					allocated = map->m_len;4266				map->m_len = allocated;4267				ext4_ext_show_leaf(inode, path);4268				goto out;4269			}4270 4271			path = ext4_ext_handle_unwritten_extents(4272				handle, inode, map, path, flags,4273				&allocated, newblock);4274			if (IS_ERR(path))4275				err = PTR_ERR(path);4276			goto out;4277		}4278	}4279 4280	/*4281	 * requested block isn't allocated yet;4282	 * we couldn't try to create block if flags doesn't contain EXT4_GET_BLOCKS_CREATE4283	 */4284	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {4285		ext4_lblk_t len;4286 4287		len = ext4_ext_determine_insert_hole(inode, path, map->m_lblk);4288 4289		map->m_pblk = 0;4290		map->m_len = min_t(unsigned int, map->m_len, len);4291		goto out;4292	}4293 4294	/*4295	 * Okay, we need to do block allocation.4296	 */4297	newex.ee_block = cpu_to_le32(map->m_lblk);4298	cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);4299 4300	/*4301	 * If we are doing bigalloc, check to see if the extent returned4302	 * by ext4_find_extent() implies a cluster we can use.4303	 */4304	if (cluster_offset && ex &&4305	    get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {4306		ar.len = allocated = map->m_len;4307		newblock = map->m_pblk;4308		goto got_allocated_blocks;4309	}4310 4311	/* find neighbour allocated blocks */4312	ar.lleft = map->m_lblk;4313	err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);4314	if (err)4315		goto out;4316	ar.lright = map->m_lblk;4317	err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);4318	if (err < 0)4319		goto out;4320 4321	/* Check if the extent after searching to the right implies a4322	 * cluster we can use. */4323	if ((sbi->s_cluster_ratio > 1) && err &&4324	    get_implied_cluster_alloc(inode->i_sb, map, &ex2, path)) {4325		ar.len = allocated = map->m_len;4326		newblock = map->m_pblk;4327		err = 0;4328		goto got_allocated_blocks;4329	}4330 4331	/*4332	 * See if request is beyond maximum number of blocks we can have in4333	 * a single extent. For an initialized extent this limit is4334	 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is4335	 * EXT_UNWRITTEN_MAX_LEN.4336	 */4337	if (map->m_len > EXT_INIT_MAX_LEN &&4338	    !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))4339		map->m_len = EXT_INIT_MAX_LEN;4340	else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&4341		 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))4342		map->m_len = EXT_UNWRITTEN_MAX_LEN;4343 4344	/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */4345	newex.ee_len = cpu_to_le16(map->m_len);4346	err = ext4_ext_check_overlap(sbi, inode, &newex, path);4347	if (err)4348		allocated = ext4_ext_get_actual_len(&newex);4349	else4350		allocated = map->m_len;4351 4352	/* allocate new block */4353	ar.inode = inode;4354	ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);4355	ar.logical = map->m_lblk;4356	/*4357	 * We calculate the offset from the beginning of the cluster4358	 * for the logical block number, since when we allocate a4359	 * physical cluster, the physical block should start at the4360	 * same offset from the beginning of the cluster.  This is4361	 * needed so that future calls to get_implied_cluster_alloc()4362	 * work correctly.4363	 */4364	offset = EXT4_LBLK_COFF(sbi, map->m_lblk);4365	ar.len = EXT4_NUM_B2C(sbi, offset+allocated);4366	ar.goal -= offset;4367	ar.logical -= offset;4368	if (S_ISREG(inode->i_mode))4369		ar.flags = EXT4_MB_HINT_DATA;4370	else4371		/* disable in-core preallocation for non-regular files */4372		ar.flags = 0;4373	if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)4374		ar.flags |= EXT4_MB_HINT_NOPREALLOC;4375	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)4376		ar.flags |= EXT4_MB_DELALLOC_RESERVED;4377	if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)4378		ar.flags |= EXT4_MB_USE_RESERVED;4379	newblock = ext4_mb_new_blocks(handle, &ar, &err);4380	if (!newblock)4381		goto out;4382	allocated_clusters = ar.len;4383	ar.len = EXT4_C2B(sbi, ar.len) - offset;4384	ext_debug(inode, "allocate new block: goal %llu, found %llu/%u, requested %u\n",4385		  ar.goal, newblock, ar.len, allocated);4386	if (ar.len > allocated)4387		ar.len = allocated;4388 4389got_allocated_blocks:4390	/* try to insert new extent into found leaf and return */4391	pblk = newblock + offset;4392	ext4_ext_store_pblock(&newex, pblk);4393	newex.ee_len = cpu_to_le16(ar.len);4394	/* Mark unwritten */4395	if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {4396		ext4_ext_mark_unwritten(&newex);4397		map->m_flags |= EXT4_MAP_UNWRITTEN;4398	}4399 4400	path = ext4_ext_insert_extent(handle, inode, path, &newex, flags);4401	if (IS_ERR(path)) {4402		err = PTR_ERR(path);4403		if (allocated_clusters) {4404			int fb_flags = 0;4405 4406			/*4407			 * free data blocks we just allocated.4408			 * not a good idea to call discard here directly,4409			 * but otherwise we'd need to call it every free().4410			 */4411			ext4_discard_preallocations(inode);4412			if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)4413				fb_flags = EXT4_FREE_BLOCKS_NO_QUOT_UPDATE;4414			ext4_free_blocks(handle, inode, NULL, newblock,4415					 EXT4_C2B(sbi, allocated_clusters),4416					 fb_flags);4417		}4418		goto out;4419	}4420 4421	/*4422	 * Cache the extent and update transaction to commit on fdatasync only4423	 * when it is _not_ an unwritten extent.4424	 */4425	if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)4426		ext4_update_inode_fsync_trans(handle, inode, 1);4427	else4428		ext4_update_inode_fsync_trans(handle, inode, 0);4429 4430	map->m_flags |= (EXT4_MAP_NEW | EXT4_MAP_MAPPED);4431	map->m_pblk = pblk;4432	map->m_len = ar.len;4433	allocated = map->m_len;4434	ext4_ext_show_leaf(inode, path);4435out:4436	ext4_free_ext_path(path);4437 4438	trace_ext4_ext_map_blocks_exit(inode, flags, map,4439				       err ? err : allocated);4440	return err ? err : allocated;4441}4442 4443int ext4_ext_truncate(handle_t *handle, struct inode *inode)4444{4445	struct super_block *sb = inode->i_sb;4446	ext4_lblk_t last_block;4447	int err = 0;4448 4449	/*4450	 * TODO: optimization is possible here.4451	 * Probably we need not scan at all,4452	 * because page truncation is enough.4453	 */4454 4455	/* we have to know where to truncate from in crash case */4456	EXT4_I(inode)->i_disksize = inode->i_size;4457	err = ext4_mark_inode_dirty(handle, inode);4458	if (err)4459		return err;4460 4461	last_block = (inode->i_size + sb->s_blocksize - 1)4462			>> EXT4_BLOCK_SIZE_BITS(sb);4463	ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);4464 4465retry_remove_space:4466	err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);4467	if (err == -ENOMEM) {4468		memalloc_retry_wait(GFP_ATOMIC);4469		goto retry_remove_space;4470	}4471	return err;4472}4473 4474static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,4475				  ext4_lblk_t len, loff_t new_size,4476				  int flags)4477{4478	struct inode *inode = file_inode(file);4479	handle_t *handle;4480	int ret = 0, ret2 = 0, ret3 = 0;4481	int retries = 0;4482	int depth = 0;4483	struct ext4_map_blocks map;4484	unsigned int credits;4485	loff_t epos;4486 4487	BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));4488	map.m_lblk = offset;4489	map.m_len = len;4490	/*4491	 * Don't normalize the request if it can fit in one extent so4492	 * that it doesn't get unnecessarily split into multiple4493	 * extents.4494	 */4495	if (len <= EXT_UNWRITTEN_MAX_LEN)4496		flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;4497 4498	/*4499	 * credits to insert 1 extent into extent tree4500	 */4501	credits = ext4_chunk_trans_blocks(inode, len);4502	depth = ext_depth(inode);4503 4504retry:4505	while (len) {4506		/*4507		 * Recalculate credits when extent tree depth changes.4508		 */4509		if (depth != ext_depth(inode)) {4510			credits = ext4_chunk_trans_blocks(inode, len);4511			depth = ext_depth(inode);4512		}4513 4514		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,4515					    credits);4516		if (IS_ERR(handle)) {4517			ret = PTR_ERR(handle);4518			break;4519		}4520		ret = ext4_map_blocks(handle, inode, &map, flags);4521		if (ret <= 0) {4522			ext4_debug("inode #%lu: block %u: len %u: "4523				   "ext4_ext_map_blocks returned %d",4524				   inode->i_ino, map.m_lblk,4525				   map.m_len, ret);4526			ext4_mark_inode_dirty(handle, inode);4527			ext4_journal_stop(handle);4528			break;4529		}4530		/*4531		 * allow a full retry cycle for any remaining allocations4532		 */4533		retries = 0;4534		map.m_lblk += ret;4535		map.m_len = len = len - ret;4536		epos = (loff_t)map.m_lblk << inode->i_blkbits;4537		inode_set_ctime_current(inode);4538		if (new_size) {4539			if (epos > new_size)4540				epos = new_size;4541			if (ext4_update_inode_size(inode, epos) & 0x1)4542				inode_set_mtime_to_ts(inode,4543						      inode_get_ctime(inode));4544		}4545		ret2 = ext4_mark_inode_dirty(handle, inode);4546		ext4_update_inode_fsync_trans(handle, inode, 1);4547		ret3 = ext4_journal_stop(handle);4548		ret2 = ret3 ? ret3 : ret2;4549		if (unlikely(ret2))4550			break;4551	}4552	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))4553		goto retry;4554 4555	return ret > 0 ? ret2 : ret;4556}4557 4558static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len);4559 4560static int ext4_insert_range(struct file *file, loff_t offset, loff_t len);4561 4562static long ext4_zero_range(struct file *file, loff_t offset,4563			    loff_t len, int mode)4564{4565	struct inode *inode = file_inode(file);4566	struct address_space *mapping = file->f_mapping;4567	handle_t *handle = NULL;4568	unsigned int max_blocks;4569	loff_t new_size = 0;4570	int ret = 0;4571	int flags;4572	int credits;4573	int partial_begin, partial_end;4574	loff_t start, end;4575	ext4_lblk_t lblk;4576	unsigned int blkbits = inode->i_blkbits;4577 4578	trace_ext4_zero_range(inode, offset, len, mode);4579 4580	/*4581	 * Round up offset. This is not fallocate, we need to zero out4582	 * blocks, so convert interior block aligned part of the range to4583	 * unwritten and possibly manually zero out unaligned parts of the4584	 * range. Here, start and partial_begin are inclusive, end and4585	 * partial_end are exclusive.4586	 */4587	start = round_up(offset, 1 << blkbits);4588	end = round_down((offset + len), 1 << blkbits);4589 4590	if (start < offset || end > offset + len)4591		return -EINVAL;4592	partial_begin = offset & ((1 << blkbits) - 1);4593	partial_end = (offset + len) & ((1 << blkbits) - 1);4594 4595	lblk = start >> blkbits;4596	max_blocks = (end >> blkbits);4597	if (max_blocks < lblk)4598		max_blocks = 0;4599	else4600		max_blocks -= lblk;4601 4602	inode_lock(inode);4603 4604	/*4605	 * Indirect files do not support unwritten extents4606	 */4607	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {4608		ret = -EOPNOTSUPP;4609		goto out_mutex;4610	}4611 4612	if (!(mode & FALLOC_FL_KEEP_SIZE) &&4613	    (offset + len > inode->i_size ||4614	     offset + len > EXT4_I(inode)->i_disksize)) {4615		new_size = offset + len;4616		ret = inode_newsize_ok(inode, new_size);4617		if (ret)4618			goto out_mutex;4619	}4620 4621	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;4622 4623	/* Wait all existing dio workers, newcomers will block on i_rwsem */4624	inode_dio_wait(inode);4625 4626	ret = file_modified(file);4627	if (ret)4628		goto out_mutex;4629 4630	/* Preallocate the range including the unaligned edges */4631	if (partial_begin || partial_end) {4632		ret = ext4_alloc_file_blocks(file,4633				round_down(offset, 1 << blkbits) >> blkbits,4634				(round_up((offset + len), 1 << blkbits) -4635				 round_down(offset, 1 << blkbits)) >> blkbits,4636				new_size, flags);4637		if (ret)4638			goto out_mutex;4639 4640	}4641 4642	/* Zero range excluding the unaligned edges */4643	if (max_blocks > 0) {4644		flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |4645			  EXT4_EX_NOCACHE);4646 4647		/*4648		 * Prevent page faults from reinstantiating pages we have4649		 * released from page cache.4650		 */4651		filemap_invalidate_lock(mapping);4652 4653		ret = ext4_break_layouts(inode);4654		if (ret) {4655			filemap_invalidate_unlock(mapping);4656			goto out_mutex;4657		}4658 4659		ret = ext4_update_disksize_before_punch(inode, offset, len);4660		if (ret) {4661			filemap_invalidate_unlock(mapping);4662			goto out_mutex;4663		}4664 4665		/*4666		 * For journalled data we need to write (and checkpoint) pages4667		 * before discarding page cache to avoid inconsitent data on4668		 * disk in case of crash before zeroing trans is committed.4669		 */4670		if (ext4_should_journal_data(inode)) {4671			ret = filemap_write_and_wait_range(mapping, start,4672							   end - 1);4673			if (ret) {4674				filemap_invalidate_unlock(mapping);4675				goto out_mutex;4676			}4677		}4678 4679		/* Now release the pages and zero block aligned part of pages */4680		truncate_pagecache_range(inode, start, end - 1);4681		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));4682 4683		ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,4684					     flags);4685		filemap_invalidate_unlock(mapping);4686		if (ret)4687			goto out_mutex;4688	}4689	if (!partial_begin && !partial_end)4690		goto out_mutex;4691 4692	/*4693	 * In worst case we have to writeout two nonadjacent unwritten4694	 * blocks and update the inode4695	 */4696	credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;4697	if (ext4_should_journal_data(inode))4698		credits += 2;4699	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);4700	if (IS_ERR(handle)) {4701		ret = PTR_ERR(handle);4702		ext4_std_error(inode->i_sb, ret);4703		goto out_mutex;4704	}4705 4706	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));4707	if (new_size)4708		ext4_update_inode_size(inode, new_size);4709	ret = ext4_mark_inode_dirty(handle, inode);4710	if (unlikely(ret))4711		goto out_handle;4712	/* Zero out partial block at the edges of the range */4713	ret = ext4_zero_partial_blocks(handle, inode, offset, len);4714	if (ret >= 0)4715		ext4_update_inode_fsync_trans(handle, inode, 1);4716 4717	if (file->f_flags & O_SYNC)4718		ext4_handle_sync(handle);4719 4720out_handle:4721	ext4_journal_stop(handle);4722out_mutex:4723	inode_unlock(inode);4724	return ret;4725}4726 4727/*4728 * preallocate space for a file. This implements ext4's fallocate file4729 * operation, which gets called from sys_fallocate system call.4730 * For block-mapped files, posix_fallocate should fall back to the method4731 * of writing zeroes to the required new blocks (the same behavior which is4732 * expected for file systems which do not support fallocate() system call).4733 */4734long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)4735{4736	struct inode *inode = file_inode(file);4737	loff_t new_size = 0;4738	unsigned int max_blocks;4739	int ret = 0;4740	int flags;4741	ext4_lblk_t lblk;4742	unsigned int blkbits = inode->i_blkbits;4743 4744	/*4745	 * Encrypted inodes can't handle collapse range or insert4746	 * range since we would need to re-encrypt blocks with a4747	 * different IV or XTS tweak (which are based on the logical4748	 * block number).4749	 */4750	if (IS_ENCRYPTED(inode) &&4751	    (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))4752		return -EOPNOTSUPP;4753 4754	/* Return error if mode is not supported */4755	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |4756		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |4757		     FALLOC_FL_INSERT_RANGE))4758		return -EOPNOTSUPP;4759 4760	inode_lock(inode);4761	ret = ext4_convert_inline_data(inode);4762	inode_unlock(inode);4763	if (ret)4764		goto exit;4765 4766	if (mode & FALLOC_FL_PUNCH_HOLE) {4767		ret = ext4_punch_hole(file, offset, len);4768		goto exit;4769	}4770 4771	if (mode & FALLOC_FL_COLLAPSE_RANGE) {4772		ret = ext4_collapse_range(file, offset, len);4773		goto exit;4774	}4775 4776	if (mode & FALLOC_FL_INSERT_RANGE) {4777		ret = ext4_insert_range(file, offset, len);4778		goto exit;4779	}4780 4781	if (mode & FALLOC_FL_ZERO_RANGE) {4782		ret = ext4_zero_range(file, offset, len, mode);4783		goto exit;4784	}4785	trace_ext4_fallocate_enter(inode, offset, len, mode);4786	lblk = offset >> blkbits;4787 4788	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);4789	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;4790 4791	inode_lock(inode);4792 4793	/*4794	 * We only support preallocation for extent-based files only4795	 */4796	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {4797		ret = -EOPNOTSUPP;4798		goto out;4799	}4800 4801	if (!(mode & FALLOC_FL_KEEP_SIZE) &&4802	    (offset + len > inode->i_size ||4803	     offset + len > EXT4_I(inode)->i_disksize)) {4804		new_size = offset + len;4805		ret = inode_newsize_ok(inode, new_size);4806		if (ret)4807			goto out;4808	}4809 4810	/* Wait all existing dio workers, newcomers will block on i_rwsem */4811	inode_dio_wait(inode);4812 4813	ret = file_modified(file);4814	if (ret)4815		goto out;4816 4817	ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);4818	if (ret)4819		goto out;4820 4821	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {4822		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,4823					EXT4_I(inode)->i_sync_tid);4824	}4825out:4826	inode_unlock(inode);4827	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);4828exit:4829	return ret;4830}4831 4832/*4833 * This function convert a range of blocks to written extents4834 * The caller of this function will pass the start offset and the size.4835 * all unwritten extents within this range will be converted to4836 * written extents.4837 *4838 * This function is called from the direct IO end io call back4839 * function, to convert the fallocated extents after IO is completed.4840 * Returns 0 on success.4841 */4842int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,4843				   loff_t offset, ssize_t len)4844{4845	unsigned int max_blocks;4846	int ret = 0, ret2 = 0, ret3 = 0;4847	struct ext4_map_blocks map;4848	unsigned int blkbits = inode->i_blkbits;4849	unsigned int credits = 0;4850 4851	map.m_lblk = offset >> blkbits;4852	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);4853 4854	if (!handle) {4855		/*4856		 * credits to insert 1 extent into extent tree4857		 */4858		credits = ext4_chunk_trans_blocks(inode, max_blocks);4859	}4860	while (ret >= 0 && ret < max_blocks) {4861		map.m_lblk += ret;4862		map.m_len = (max_blocks -= ret);4863		if (credits) {4864			handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,4865						    credits);4866			if (IS_ERR(handle)) {4867				ret = PTR_ERR(handle);4868				break;4869			}4870		}4871		ret = ext4_map_blocks(handle, inode, &map,4872				      EXT4_GET_BLOCKS_IO_CONVERT_EXT);4873		if (ret <= 0)4874			ext4_warning(inode->i_sb,4875				     "inode #%lu: block %u: len %u: "4876				     "ext4_ext_map_blocks returned %d",4877				     inode->i_ino, map.m_lblk,4878				     map.m_len, ret);4879		ret2 = ext4_mark_inode_dirty(handle, inode);4880		if (credits) {4881			ret3 = ext4_journal_stop(handle);4882			if (unlikely(ret3))4883				ret2 = ret3;4884		}4885 4886		if (ret <= 0 || ret2)4887			break;4888	}4889	return ret > 0 ? ret2 : ret;4890}4891 4892int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)4893{4894	int ret = 0, err = 0;4895	struct ext4_io_end_vec *io_end_vec;4896 4897	/*4898	 * This is somewhat ugly but the idea is clear: When transaction is4899	 * reserved, everything goes into it. Otherwise we rather start several4900	 * smaller transactions for conversion of each extent separately.4901	 */4902	if (handle) {4903		handle = ext4_journal_start_reserved(handle,4904						     EXT4_HT_EXT_CONVERT);4905		if (IS_ERR(handle))4906			return PTR_ERR(handle);4907	}4908 4909	list_for_each_entry(io_end_vec, &io_end->list_vec, list) {4910		ret = ext4_convert_unwritten_extents(handle, io_end->inode,4911						     io_end_vec->offset,4912						     io_end_vec->size);4913		if (ret)4914			break;4915	}4916 4917	if (handle)4918		err = ext4_journal_stop(handle);4919 4920	return ret < 0 ? ret : err;4921}4922 4923static int ext4_iomap_xattr_fiemap(struct inode *inode, struct iomap *iomap)4924{4925	__u64 physical = 0;4926	__u64 length = 0;4927	int blockbits = inode->i_sb->s_blocksize_bits;4928	int error = 0;4929	u16 iomap_type;4930 4931	/* in-inode? */4932	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {4933		struct ext4_iloc iloc;4934		int offset;	/* offset of xattr in inode */4935 4936		error = ext4_get_inode_loc(inode, &iloc);4937		if (error)4938			return error;4939		physical = (__u64)iloc.bh->b_blocknr << blockbits;4940		offset = EXT4_GOOD_OLD_INODE_SIZE +4941				EXT4_I(inode)->i_extra_isize;4942		physical += offset;4943		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;4944		brelse(iloc.bh);4945		iomap_type = IOMAP_INLINE;4946	} else if (EXT4_I(inode)->i_file_acl) { /* external block */4947		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;4948		length = inode->i_sb->s_blocksize;4949		iomap_type = IOMAP_MAPPED;4950	} else {4951		/* no in-inode or external block for xattr, so return -ENOENT */4952		error = -ENOENT;4953		goto out;4954	}4955 4956	iomap->addr = physical;4957	iomap->offset = 0;4958	iomap->length = length;4959	iomap->type = iomap_type;4960	iomap->flags = 0;4961out:4962	return error;4963}4964 4965static int ext4_iomap_xattr_begin(struct inode *inode, loff_t offset,4966				  loff_t length, unsigned flags,4967				  struct iomap *iomap, struct iomap *srcmap)4968{4969	int error;4970 4971	error = ext4_iomap_xattr_fiemap(inode, iomap);4972	if (error == 0 && (offset >= iomap->length))4973		error = -ENOENT;4974	return error;4975}4976 4977static const struct iomap_ops ext4_iomap_xattr_ops = {4978	.iomap_begin		= ext4_iomap_xattr_begin,4979};4980 4981static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)4982{4983	u64 maxbytes;4984 4985	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))4986		maxbytes = inode->i_sb->s_maxbytes;4987	else4988		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;4989 4990	if (*len == 0)4991		return -EINVAL;4992	if (start > maxbytes)4993		return -EFBIG;4994 4995	/*4996	 * Shrink request scope to what the fs can actually handle.4997	 */4998	if (*len > maxbytes || (maxbytes - *len) < start)4999		*len = maxbytes - start;5000	return 0;5001}5002 5003int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,5004		u64 start, u64 len)5005{5006	int error = 0;5007 5008	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {5009		error = ext4_ext_precache(inode);5010		if (error)5011			return error;5012		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;5013	}5014 5015	/*5016	 * For bitmap files the maximum size limit could be smaller than5017	 * s_maxbytes, so check len here manually instead of just relying on the5018	 * generic check.5019	 */5020	error = ext4_fiemap_check_ranges(inode, start, &len);5021	if (error)5022		return error;5023 5024	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {5025		fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;5026		return iomap_fiemap(inode, fieinfo, start, len,5027				    &ext4_iomap_xattr_ops);5028	}5029 5030	return iomap_fiemap(inode, fieinfo, start, len, &ext4_iomap_report_ops);5031}5032 5033int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,5034		      __u64 start, __u64 len)5035{5036	ext4_lblk_t start_blk, len_blks;5037	__u64 last_blk;5038	int error = 0;5039 5040	if (ext4_has_inline_data(inode)) {5041		int has_inline;5042 5043		down_read(&EXT4_I(inode)->xattr_sem);5044		has_inline = ext4_has_inline_data(inode);5045		up_read(&EXT4_I(inode)->xattr_sem);5046		if (has_inline)5047			return 0;5048	}5049 5050	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {5051		error = ext4_ext_precache(inode);5052		if (error)5053			return error;5054		fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;5055	}5056 5057	error = fiemap_prep(inode, fieinfo, start, &len, 0);5058	if (error)5059		return error;5060 5061	error = ext4_fiemap_check_ranges(inode, start, &len);5062	if (error)5063		return error;5064 5065	start_blk = start >> inode->i_sb->s_blocksize_bits;5066	last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;5067	if (last_blk >= EXT_MAX_BLOCKS)5068		last_blk = EXT_MAX_BLOCKS-1;5069	len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;5070 5071	/*5072	 * Walk the extent tree gathering extent information5073	 * and pushing extents back to the user.5074	 */5075	return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);5076}5077 5078/*5079 * ext4_ext_shift_path_extents:5080 * Shift the extents of a path structure lying between path[depth].p_ext5081 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells5082 * if it is right shift or left shift operation.5083 */5084static int5085ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,5086			    struct inode *inode, handle_t *handle,5087			    enum SHIFT_DIRECTION SHIFT)5088{5089	int depth, err = 0;5090	struct ext4_extent *ex_start, *ex_last;5091	bool update = false;5092	int credits, restart_credits;5093	depth = path->p_depth;5094 5095	while (depth >= 0) {5096		if (depth == path->p_depth) {5097			ex_start = path[depth].p_ext;5098			if (!ex_start)5099				return -EFSCORRUPTED;5100 5101			ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);5102			/* leaf + sb + inode */5103			credits = 3;5104			if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {5105				update = true;5106				/* extent tree + sb + inode */5107				credits = depth + 2;5108			}5109 5110			restart_credits = ext4_writepage_trans_blocks(inode);5111			err = ext4_datasem_ensure_credits(handle, inode, credits,5112					restart_credits, 0);5113			if (err) {5114				if (err > 0)5115					err = -EAGAIN;5116				goto out;5117			}5118 5119			err = ext4_ext_get_access(handle, inode, path + depth);5120			if (err)5121				goto out;5122 5123			while (ex_start <= ex_last) {5124				if (SHIFT == SHIFT_LEFT) {5125					le32_add_cpu(&ex_start->ee_block,5126						-shift);5127					/* Try to merge to the left. */5128					if ((ex_start >5129					    EXT_FIRST_EXTENT(path[depth].p_hdr))5130					    &&5131					    ext4_ext_try_to_merge_right(inode,5132					    path, ex_start - 1))5133						ex_last--;5134					else5135						ex_start++;5136				} else {5137					le32_add_cpu(&ex_last->ee_block, shift);5138					ext4_ext_try_to_merge_right(inode, path,5139						ex_last);5140					ex_last--;5141				}5142			}5143			err = ext4_ext_dirty(handle, inode, path + depth);5144			if (err)5145				goto out;5146 5147			if (--depth < 0 || !update)5148				break;5149		}5150 5151		/* Update index too */5152		err = ext4_ext_get_access(handle, inode, path + depth);5153		if (err)5154			goto out;5155 5156		if (SHIFT == SHIFT_LEFT)5157			le32_add_cpu(&path[depth].p_idx->ei_block, -shift);5158		else5159			le32_add_cpu(&path[depth].p_idx->ei_block, shift);5160		err = ext4_ext_dirty(handle, inode, path + depth);5161		if (err)5162			goto out;5163 5164		/* we are done if current index is not a starting index */5165		if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))5166			break;5167 5168		depth--;5169	}5170 5171out:5172	return err;5173}5174 5175/*5176 * ext4_ext_shift_extents:5177 * All the extents which lies in the range from @start to the last allocated5178 * block for the @inode are shifted either towards left or right (depending5179 * upon @SHIFT) by @shift blocks.5180 * On success, 0 is returned, error otherwise.5181 */5182static int5183ext4_ext_shift_extents(struct inode *inode, handle_t *handle,5184		       ext4_lblk_t start, ext4_lblk_t shift,5185		       enum SHIFT_DIRECTION SHIFT)5186{5187	struct ext4_ext_path *path;5188	int ret = 0, depth;5189	struct ext4_extent *extent;5190	ext4_lblk_t stop, *iterator, ex_start, ex_end;5191	ext4_lblk_t tmp = EXT_MAX_BLOCKS;5192 5193	/* Let path point to the last extent */5194	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,5195				EXT4_EX_NOCACHE);5196	if (IS_ERR(path))5197		return PTR_ERR(path);5198 5199	depth = path->p_depth;5200	extent = path[depth].p_ext;5201	if (!extent)5202		goto out;5203 5204	stop = le32_to_cpu(extent->ee_block);5205 5206       /*5207	* For left shifts, make sure the hole on the left is big enough to5208	* accommodate the shift.  For right shifts, make sure the last extent5209	* won't be shifted beyond EXT_MAX_BLOCKS.5210	*/5211	if (SHIFT == SHIFT_LEFT) {5212		path = ext4_find_extent(inode, start - 1, path,5213					EXT4_EX_NOCACHE);5214		if (IS_ERR(path))5215			return PTR_ERR(path);5216		depth = path->p_depth;5217		extent =  path[depth].p_ext;5218		if (extent) {5219			ex_start = le32_to_cpu(extent->ee_block);5220			ex_end = le32_to_cpu(extent->ee_block) +5221				ext4_ext_get_actual_len(extent);5222		} else {5223			ex_start = 0;5224			ex_end = 0;5225		}5226 5227		if ((start == ex_start && shift > ex_start) ||5228		    (shift > start - ex_end)) {5229			ret = -EINVAL;5230			goto out;5231		}5232	} else {5233		if (shift > EXT_MAX_BLOCKS -5234		    (stop + ext4_ext_get_actual_len(extent))) {5235			ret = -EINVAL;5236			goto out;5237		}5238	}5239 5240	/*5241	 * In case of left shift, iterator points to start and it is increased5242	 * till we reach stop. In case of right shift, iterator points to stop5243	 * and it is decreased till we reach start.5244	 */5245again:5246	ret = 0;5247	if (SHIFT == SHIFT_LEFT)5248		iterator = &start;5249	else5250		iterator = &stop;5251 5252	if (tmp != EXT_MAX_BLOCKS)5253		*iterator = tmp;5254 5255	/*5256	 * Its safe to start updating extents.  Start and stop are unsigned, so5257	 * in case of right shift if extent with 0 block is reached, iterator5258	 * becomes NULL to indicate the end of the loop.5259	 */5260	while (iterator && start <= stop) {5261		path = ext4_find_extent(inode, *iterator, path,5262					EXT4_EX_NOCACHE);5263		if (IS_ERR(path))5264			return PTR_ERR(path);5265		depth = path->p_depth;5266		extent = path[depth].p_ext;5267		if (!extent) {5268			EXT4_ERROR_INODE(inode, "unexpected hole at %lu",5269					 (unsigned long) *iterator);5270			return -EFSCORRUPTED;5271		}5272		if (SHIFT == SHIFT_LEFT && *iterator >5273		    le32_to_cpu(extent->ee_block)) {5274			/* Hole, move to the next extent */5275			if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {5276				path[depth].p_ext++;5277			} else {5278				*iterator = ext4_ext_next_allocated_block(path);5279				continue;5280			}5281		}5282 5283		tmp = *iterator;5284		if (SHIFT == SHIFT_LEFT) {5285			extent = EXT_LAST_EXTENT(path[depth].p_hdr);5286			*iterator = le32_to_cpu(extent->ee_block) +5287					ext4_ext_get_actual_len(extent);5288		} else {5289			extent = EXT_FIRST_EXTENT(path[depth].p_hdr);5290			if (le32_to_cpu(extent->ee_block) > start)5291				*iterator = le32_to_cpu(extent->ee_block) - 1;5292			else if (le32_to_cpu(extent->ee_block) == start)5293				iterator = NULL;5294			else {5295				extent = EXT_LAST_EXTENT(path[depth].p_hdr);5296				while (le32_to_cpu(extent->ee_block) >= start)5297					extent--;5298 5299				if (extent == EXT_LAST_EXTENT(path[depth].p_hdr))5300					break;5301 5302				extent++;5303				iterator = NULL;5304			}5305			path[depth].p_ext = extent;5306		}5307		ret = ext4_ext_shift_path_extents(path, shift, inode,5308				handle, SHIFT);5309		/* iterator can be NULL which means we should break */5310		if (ret == -EAGAIN)5311			goto again;5312		if (ret)5313			break;5314	}5315out:5316	ext4_free_ext_path(path);5317	return ret;5318}5319 5320/*5321 * ext4_collapse_range:5322 * This implements the fallocate's collapse range functionality for ext45323 * Returns: 0 and non-zero on error.5324 */5325static int ext4_collapse_range(struct file *file, loff_t offset, loff_t len)5326{5327	struct inode *inode = file_inode(file);5328	struct super_block *sb = inode->i_sb;5329	struct address_space *mapping = inode->i_mapping;5330	ext4_lblk_t punch_start, punch_stop;5331	handle_t *handle;5332	unsigned int credits;5333	loff_t new_size, ioffset;5334	int ret;5335 5336	/*5337	 * We need to test this early because xfstests assumes that a5338	 * collapse range of (0, 1) will return EOPNOTSUPP if the file5339	 * system does not support collapse range.5340	 */5341	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))5342		return -EOPNOTSUPP;5343 5344	/* Collapse range works only on fs cluster size aligned regions. */5345	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))5346		return -EINVAL;5347 5348	trace_ext4_collapse_range(inode, offset, len);5349 5350	punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);5351	punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);5352 5353	inode_lock(inode);5354	/*5355	 * There is no need to overlap collapse range with EOF, in which case5356	 * it is effectively a truncate operation5357	 */5358	if (offset + len >= inode->i_size) {5359		ret = -EINVAL;5360		goto out_mutex;5361	}5362 5363	/* Currently just for extent based files */5364	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {5365		ret = -EOPNOTSUPP;5366		goto out_mutex;5367	}5368 5369	/* Wait for existing dio to complete */5370	inode_dio_wait(inode);5371 5372	ret = file_modified(file);5373	if (ret)5374		goto out_mutex;5375 5376	/*5377	 * Prevent page faults from reinstantiating pages we have released from5378	 * page cache.5379	 */5380	filemap_invalidate_lock(mapping);5381 5382	ret = ext4_break_layouts(inode);5383	if (ret)5384		goto out_mmap;5385 5386	/*5387	 * Need to round down offset to be aligned with page size boundary5388	 * for page size > block size.5389	 */5390	ioffset = round_down(offset, PAGE_SIZE);5391	/*5392	 * Write tail of the last page before removed range since it will get5393	 * removed from the page cache below.5394	 */5395	ret = filemap_write_and_wait_range(mapping, ioffset, offset);5396	if (ret)5397		goto out_mmap;5398	/*5399	 * Write data that will be shifted to preserve them when discarding5400	 * page cache below. We are also protected from pages becoming dirty5401	 * by i_rwsem and invalidate_lock.5402	 */5403	ret = filemap_write_and_wait_range(mapping, offset + len,5404					   LLONG_MAX);5405	if (ret)5406		goto out_mmap;5407	truncate_pagecache(inode, ioffset);5408 5409	credits = ext4_writepage_trans_blocks(inode);5410	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);5411	if (IS_ERR(handle)) {5412		ret = PTR_ERR(handle);5413		goto out_mmap;5414	}5415	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);5416 5417	down_write(&EXT4_I(inode)->i_data_sem);5418	ext4_discard_preallocations(inode);5419	ext4_es_remove_extent(inode, punch_start, EXT_MAX_BLOCKS - punch_start);5420 5421	ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);5422	if (ret) {5423		up_write(&EXT4_I(inode)->i_data_sem);5424		goto out_stop;5425	}5426	ext4_discard_preallocations(inode);5427 5428	ret = ext4_ext_shift_extents(inode, handle, punch_stop,5429				     punch_stop - punch_start, SHIFT_LEFT);5430	if (ret) {5431		up_write(&EXT4_I(inode)->i_data_sem);5432		goto out_stop;5433	}5434 5435	new_size = inode->i_size - len;5436	i_size_write(inode, new_size);5437	EXT4_I(inode)->i_disksize = new_size;5438 5439	up_write(&EXT4_I(inode)->i_data_sem);5440	if (IS_SYNC(inode))5441		ext4_handle_sync(handle);5442	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));5443	ret = ext4_mark_inode_dirty(handle, inode);5444	ext4_update_inode_fsync_trans(handle, inode, 1);5445 5446out_stop:5447	ext4_journal_stop(handle);5448out_mmap:5449	filemap_invalidate_unlock(mapping);5450out_mutex:5451	inode_unlock(inode);5452	return ret;5453}5454 5455/*5456 * ext4_insert_range:5457 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.5458 * The data blocks starting from @offset to the EOF are shifted by @len5459 * towards right to create a hole in the @inode. Inode size is increased5460 * by len bytes.5461 * Returns 0 on success, error otherwise.5462 */5463static int ext4_insert_range(struct file *file, loff_t offset, loff_t len)5464{5465	struct inode *inode = file_inode(file);5466	struct super_block *sb = inode->i_sb;5467	struct address_space *mapping = inode->i_mapping;5468	handle_t *handle;5469	struct ext4_ext_path *path;5470	struct ext4_extent *extent;5471	ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;5472	unsigned int credits, ee_len;5473	int ret = 0, depth, split_flag = 0;5474	loff_t ioffset;5475 5476	/*5477	 * We need to test this early because xfstests assumes that an5478	 * insert range of (0, 1) will return EOPNOTSUPP if the file5479	 * system does not support insert range.5480	 */5481	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))5482		return -EOPNOTSUPP;5483 5484	/* Insert range works only on fs cluster size aligned regions. */5485	if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))5486		return -EINVAL;5487 5488	trace_ext4_insert_range(inode, offset, len);5489 5490	offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);5491	len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);5492 5493	inode_lock(inode);5494	/* Currently just for extent based files */5495	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {5496		ret = -EOPNOTSUPP;5497		goto out_mutex;5498	}5499 5500	/* Check whether the maximum file size would be exceeded */5501	if (len > inode->i_sb->s_maxbytes - inode->i_size) {5502		ret = -EFBIG;5503		goto out_mutex;5504	}5505 5506	/* Offset must be less than i_size */5507	if (offset >= inode->i_size) {5508		ret = -EINVAL;5509		goto out_mutex;5510	}5511 5512	/* Wait for existing dio to complete */5513	inode_dio_wait(inode);5514 5515	ret = file_modified(file);5516	if (ret)5517		goto out_mutex;5518 5519	/*5520	 * Prevent page faults from reinstantiating pages we have released from5521	 * page cache.5522	 */5523	filemap_invalidate_lock(mapping);5524 5525	ret = ext4_break_layouts(inode);5526	if (ret)5527		goto out_mmap;5528 5529	/*5530	 * Need to round down to align start offset to page size boundary5531	 * for page size > block size.5532	 */5533	ioffset = round_down(offset, PAGE_SIZE);5534	/* Write out all dirty pages */5535	ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,5536			LLONG_MAX);5537	if (ret)5538		goto out_mmap;5539	truncate_pagecache(inode, ioffset);5540 5541	credits = ext4_writepage_trans_blocks(inode);5542	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);5543	if (IS_ERR(handle)) {5544		ret = PTR_ERR(handle);5545		goto out_mmap;5546	}5547	ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE, handle);5548 5549	/* Expand file to avoid data loss if there is error while shifting */5550	inode->i_size += len;5551	EXT4_I(inode)->i_disksize += len;5552	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));5553	ret = ext4_mark_inode_dirty(handle, inode);5554	if (ret)5555		goto out_stop;5556 5557	down_write(&EXT4_I(inode)->i_data_sem);5558	ext4_discard_preallocations(inode);5559 5560	path = ext4_find_extent(inode, offset_lblk, NULL, 0);5561	if (IS_ERR(path)) {5562		up_write(&EXT4_I(inode)->i_data_sem);5563		ret = PTR_ERR(path);5564		goto out_stop;5565	}5566 5567	depth = ext_depth(inode);5568	extent = path[depth].p_ext;5569	if (extent) {5570		ee_start_lblk = le32_to_cpu(extent->ee_block);5571		ee_len = ext4_ext_get_actual_len(extent);5572 5573		/*5574		 * If offset_lblk is not the starting block of extent, split5575		 * the extent @offset_lblk5576		 */5577		if ((offset_lblk > ee_start_lblk) &&5578				(offset_lblk < (ee_start_lblk + ee_len))) {5579			if (ext4_ext_is_unwritten(extent))5580				split_flag = EXT4_EXT_MARK_UNWRIT1 |5581					EXT4_EXT_MARK_UNWRIT2;5582			path = ext4_split_extent_at(handle, inode, path,5583					offset_lblk, split_flag,5584					EXT4_EX_NOCACHE |5585					EXT4_GET_BLOCKS_PRE_IO |5586					EXT4_GET_BLOCKS_METADATA_NOFAIL);5587		}5588 5589		if (IS_ERR(path)) {5590			up_write(&EXT4_I(inode)->i_data_sem);5591			ret = PTR_ERR(path);5592			goto out_stop;5593		}5594	}5595 5596	ext4_free_ext_path(path);5597	ext4_es_remove_extent(inode, offset_lblk, EXT_MAX_BLOCKS - offset_lblk);5598 5599	/*5600	 * if offset_lblk lies in a hole which is at start of file, use5601	 * ee_start_lblk to shift extents5602	 */5603	ret = ext4_ext_shift_extents(inode, handle,5604		max(ee_start_lblk, offset_lblk), len_lblk, SHIFT_RIGHT);5605 5606	up_write(&EXT4_I(inode)->i_data_sem);5607	if (IS_SYNC(inode))5608		ext4_handle_sync(handle);5609	if (ret >= 0)5610		ext4_update_inode_fsync_trans(handle, inode, 1);5611 5612out_stop:5613	ext4_journal_stop(handle);5614out_mmap:5615	filemap_invalidate_unlock(mapping);5616out_mutex:5617	inode_unlock(inode);5618	return ret;5619}5620 5621/**5622 * ext4_swap_extents() - Swap extents between two inodes5623 * @handle: handle for this transaction5624 * @inode1:	First inode5625 * @inode2:	Second inode5626 * @lblk1:	Start block for first inode5627 * @lblk2:	Start block for second inode5628 * @count:	Number of blocks to swap5629 * @unwritten: Mark second inode's extents as unwritten after swap5630 * @erp:	Pointer to save error value5631 *5632 * This helper routine does exactly what is promise "swap extents". All other5633 * stuff such as page-cache locking consistency, bh mapping consistency or5634 * extent's data copying must be performed by caller.5635 * Locking:5636 *		i_rwsem is held for both inodes5637 * 		i_data_sem is locked for write for both inodes5638 * Assumptions:5639 *		All pages from requested range are locked for both inodes5640 */5641int5642ext4_swap_extents(handle_t *handle, struct inode *inode1,5643		  struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,5644		  ext4_lblk_t count, int unwritten, int *erp)5645{5646	struct ext4_ext_path *path1 = NULL;5647	struct ext4_ext_path *path2 = NULL;5648	int replaced_count = 0;5649 5650	BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));5651	BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));5652	BUG_ON(!inode_is_locked(inode1));5653	BUG_ON(!inode_is_locked(inode2));5654 5655	ext4_es_remove_extent(inode1, lblk1, count);5656	ext4_es_remove_extent(inode2, lblk2, count);5657 5658	while (count) {5659		struct ext4_extent *ex1, *ex2, tmp_ex;5660		ext4_lblk_t e1_blk, e2_blk;5661		int e1_len, e2_len, len;5662		int split = 0;5663 5664		path1 = ext4_find_extent(inode1, lblk1, path1, EXT4_EX_NOCACHE);5665		if (IS_ERR(path1)) {5666			*erp = PTR_ERR(path1);5667			goto errout;5668		}5669		path2 = ext4_find_extent(inode2, lblk2, path2, EXT4_EX_NOCACHE);5670		if (IS_ERR(path2)) {5671			*erp = PTR_ERR(path2);5672			goto errout;5673		}5674		ex1 = path1[path1->p_depth].p_ext;5675		ex2 = path2[path2->p_depth].p_ext;5676		/* Do we have something to swap ? */5677		if (unlikely(!ex2 || !ex1))5678			goto errout;5679 5680		e1_blk = le32_to_cpu(ex1->ee_block);5681		e2_blk = le32_to_cpu(ex2->ee_block);5682		e1_len = ext4_ext_get_actual_len(ex1);5683		e2_len = ext4_ext_get_actual_len(ex2);5684 5685		/* Hole handling */5686		if (!in_range(lblk1, e1_blk, e1_len) ||5687		    !in_range(lblk2, e2_blk, e2_len)) {5688			ext4_lblk_t next1, next2;5689 5690			/* if hole after extent, then go to next extent */5691			next1 = ext4_ext_next_allocated_block(path1);5692			next2 = ext4_ext_next_allocated_block(path2);5693			/* If hole before extent, then shift to that extent */5694			if (e1_blk > lblk1)5695				next1 = e1_blk;5696			if (e2_blk > lblk2)5697				next2 = e2_blk;5698			/* Do we have something to swap */5699			if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)5700				goto errout;5701			/* Move to the rightest boundary */5702			len = next1 - lblk1;5703			if (len < next2 - lblk2)5704				len = next2 - lblk2;5705			if (len > count)5706				len = count;5707			lblk1 += len;5708			lblk2 += len;5709			count -= len;5710			continue;5711		}5712 5713		/* Prepare left boundary */5714		if (e1_blk < lblk1) {5715			split = 1;5716			path1 = ext4_force_split_extent_at(handle, inode1,5717							   path1, lblk1, 0);5718			if (IS_ERR(path1)) {5719				*erp = PTR_ERR(path1);5720				goto errout;5721			}5722		}5723		if (e2_blk < lblk2) {5724			split = 1;5725			path2 = ext4_force_split_extent_at(handle, inode2,5726							   path2, lblk2, 0);5727			if (IS_ERR(path2)) {5728				*erp = PTR_ERR(path2);5729				goto errout;5730			}5731		}5732		/* ext4_split_extent_at() may result in leaf extent split,5733		 * path must to be revalidated. */5734		if (split)5735			continue;5736 5737		/* Prepare right boundary */5738		len = count;5739		if (len > e1_blk + e1_len - lblk1)5740			len = e1_blk + e1_len - lblk1;5741		if (len > e2_blk + e2_len - lblk2)5742			len = e2_blk + e2_len - lblk2;5743 5744		if (len != e1_len) {5745			split = 1;5746			path1 = ext4_force_split_extent_at(handle, inode1,5747							path1, lblk1 + len, 0);5748			if (IS_ERR(path1)) {5749				*erp = PTR_ERR(path1);5750				goto errout;5751			}5752		}5753		if (len != e2_len) {5754			split = 1;5755			path2 = ext4_force_split_extent_at(handle, inode2,5756							path2, lblk2 + len, 0);5757			if (IS_ERR(path2)) {5758				*erp = PTR_ERR(path2);5759				goto errout;5760			}5761		}5762		/* ext4_split_extent_at() may result in leaf extent split,5763		 * path must to be revalidated. */5764		if (split)5765			continue;5766 5767		BUG_ON(e2_len != e1_len);5768		*erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);5769		if (unlikely(*erp))5770			goto errout;5771		*erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);5772		if (unlikely(*erp))5773			goto errout;5774 5775		/* Both extents are fully inside boundaries. Swap it now */5776		tmp_ex = *ex1;5777		ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));5778		ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));5779		ex1->ee_len = cpu_to_le16(e2_len);5780		ex2->ee_len = cpu_to_le16(e1_len);5781		if (unwritten)5782			ext4_ext_mark_unwritten(ex2);5783		if (ext4_ext_is_unwritten(&tmp_ex))5784			ext4_ext_mark_unwritten(ex1);5785 5786		ext4_ext_try_to_merge(handle, inode2, path2, ex2);5787		ext4_ext_try_to_merge(handle, inode1, path1, ex1);5788		*erp = ext4_ext_dirty(handle, inode2, path2 +5789				      path2->p_depth);5790		if (unlikely(*erp))5791			goto errout;5792		*erp = ext4_ext_dirty(handle, inode1, path1 +5793				      path1->p_depth);5794		/*5795		 * Looks scarry ah..? second inode already points to new blocks,5796		 * and it was successfully dirtied. But luckily error may happen5797		 * only due to journal error, so full transaction will be5798		 * aborted anyway.5799		 */5800		if (unlikely(*erp))5801			goto errout;5802 5803		lblk1 += len;5804		lblk2 += len;5805		replaced_count += len;5806		count -= len;5807	}5808 5809errout:5810	ext4_free_ext_path(path1);5811	ext4_free_ext_path(path2);5812	return replaced_count;5813}5814 5815/*5816 * ext4_clu_mapped - determine whether any block in a logical cluster has5817 *                   been mapped to a physical cluster5818 *5819 * @inode - file containing the logical cluster5820 * @lclu - logical cluster of interest5821 *5822 * Returns 1 if any block in the logical cluster is mapped, signifying5823 * that a physical cluster has been allocated for it.  Otherwise,5824 * returns 0.  Can also return negative error codes.  Derived from5825 * ext4_ext_map_blocks().5826 */5827int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)5828{5829	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);5830	struct ext4_ext_path *path;5831	int depth, mapped = 0, err = 0;5832	struct ext4_extent *extent;5833	ext4_lblk_t first_lblk, first_lclu, last_lclu;5834 5835	/*5836	 * if data can be stored inline, the logical cluster isn't5837	 * mapped - no physical clusters have been allocated, and the5838	 * file has no extents5839	 */5840	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) ||5841	    ext4_has_inline_data(inode))5842		return 0;5843 5844	/* search for the extent closest to the first block in the cluster */5845	path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);5846	if (IS_ERR(path))5847		return PTR_ERR(path);5848 5849	depth = ext_depth(inode);5850 5851	/*5852	 * A consistent leaf must not be empty.  This situation is possible,5853	 * though, _during_ tree modification, and it's why an assert can't5854	 * be put in ext4_find_extent().5855	 */5856	if (unlikely(path[depth].p_ext == NULL && depth != 0)) {5857		EXT4_ERROR_INODE(inode,5858		    "bad extent address - lblock: %lu, depth: %d, pblock: %lld",5859				 (unsigned long) EXT4_C2B(sbi, lclu),5860				 depth, path[depth].p_block);5861		err = -EFSCORRUPTED;5862		goto out;5863	}5864 5865	extent = path[depth].p_ext;5866 5867	/* can't be mapped if the extent tree is empty */5868	if (extent == NULL)5869		goto out;5870 5871	first_lblk = le32_to_cpu(extent->ee_block);5872	first_lclu = EXT4_B2C(sbi, first_lblk);5873 5874	/*5875	 * Three possible outcomes at this point - found extent spanning5876	 * the target cluster, to the left of the target cluster, or to the5877	 * right of the target cluster.  The first two cases are handled here.5878	 * The last case indicates the target cluster is not mapped.5879	 */5880	if (lclu >= first_lclu) {5881		last_lclu = EXT4_B2C(sbi, first_lblk +5882				     ext4_ext_get_actual_len(extent) - 1);5883		if (lclu <= last_lclu) {5884			mapped = 1;5885		} else {5886			first_lblk = ext4_ext_next_allocated_block(path);5887			first_lclu = EXT4_B2C(sbi, first_lblk);5888			if (lclu == first_lclu)5889				mapped = 1;5890		}5891	}5892 5893out:5894	ext4_free_ext_path(path);5895 5896	return err ? err : mapped;5897}5898 5899/*5900 * Updates physical block address and unwritten status of extent5901 * starting at lblk start and of len. If such an extent doesn't exist,5902 * this function splits the extent tree appropriately to create an5903 * extent like this.  This function is called in the fast commit5904 * replay path.  Returns 0 on success and error on failure.5905 */5906int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,5907			      int len, int unwritten, ext4_fsblk_t pblk)5908{5909	struct ext4_ext_path *path;5910	struct ext4_extent *ex;5911	int ret;5912 5913	path = ext4_find_extent(inode, start, NULL, 0);5914	if (IS_ERR(path))5915		return PTR_ERR(path);5916	ex = path[path->p_depth].p_ext;5917	if (!ex) {5918		ret = -EFSCORRUPTED;5919		goto out;5920	}5921 5922	if (le32_to_cpu(ex->ee_block) != start ||5923		ext4_ext_get_actual_len(ex) != len) {5924		/* We need to split this extent to match our extent first */5925		down_write(&EXT4_I(inode)->i_data_sem);5926		path = ext4_force_split_extent_at(NULL, inode, path, start, 1);5927		up_write(&EXT4_I(inode)->i_data_sem);5928		if (IS_ERR(path)) {5929			ret = PTR_ERR(path);5930			goto out;5931		}5932 5933		path = ext4_find_extent(inode, start, path, 0);5934		if (IS_ERR(path))5935			return PTR_ERR(path);5936 5937		ex = path[path->p_depth].p_ext;5938		WARN_ON(le32_to_cpu(ex->ee_block) != start);5939 5940		if (ext4_ext_get_actual_len(ex) != len) {5941			down_write(&EXT4_I(inode)->i_data_sem);5942			path = ext4_force_split_extent_at(NULL, inode, path,5943							  start + len, 1);5944			up_write(&EXT4_I(inode)->i_data_sem);5945			if (IS_ERR(path)) {5946				ret = PTR_ERR(path);5947				goto out;5948			}5949 5950			path = ext4_find_extent(inode, start, path, 0);5951			if (IS_ERR(path))5952				return PTR_ERR(path);5953			ex = path[path->p_depth].p_ext;5954		}5955	}5956	if (unwritten)5957		ext4_ext_mark_unwritten(ex);5958	else5959		ext4_ext_mark_initialized(ex);5960	ext4_ext_store_pblock(ex, pblk);5961	down_write(&EXT4_I(inode)->i_data_sem);5962	ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);5963	up_write(&EXT4_I(inode)->i_data_sem);5964out:5965	ext4_free_ext_path(path);5966	ext4_mark_inode_dirty(NULL, inode);5967	return ret;5968}5969 5970/* Try to shrink the extent tree */5971void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)5972{5973	struct ext4_ext_path *path = NULL;5974	struct ext4_extent *ex;5975	ext4_lblk_t old_cur, cur = 0;5976 5977	while (cur < end) {5978		path = ext4_find_extent(inode, cur, NULL, 0);5979		if (IS_ERR(path))5980			return;5981		ex = path[path->p_depth].p_ext;5982		if (!ex) {5983			ext4_free_ext_path(path);5984			ext4_mark_inode_dirty(NULL, inode);5985			return;5986		}5987		old_cur = cur;5988		cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);5989		if (cur <= old_cur)5990			cur = old_cur + 1;5991		ext4_ext_try_to_merge(NULL, inode, path, ex);5992		down_write(&EXT4_I(inode)->i_data_sem);5993		ext4_ext_dirty(NULL, inode, &path[path->p_depth]);5994		up_write(&EXT4_I(inode)->i_data_sem);5995		ext4_mark_inode_dirty(NULL, inode);5996		ext4_free_ext_path(path);5997	}5998}5999 6000/* Check if *cur is a hole and if it is, skip it */6001static int skip_hole(struct inode *inode, ext4_lblk_t *cur)6002{6003	int ret;6004	struct ext4_map_blocks map;6005 6006	map.m_lblk = *cur;6007	map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;6008 6009	ret = ext4_map_blocks(NULL, inode, &map, 0);6010	if (ret < 0)6011		return ret;6012	if (ret != 0)6013		return 0;6014	*cur = *cur + map.m_len;6015	return 0;6016}6017 6018/* Count number of blocks used by this inode and update i_blocks */6019int ext4_ext_replay_set_iblocks(struct inode *inode)6020{6021	struct ext4_ext_path *path = NULL, *path2 = NULL;6022	struct ext4_extent *ex;6023	ext4_lblk_t cur = 0, end;6024	int numblks = 0, i, ret = 0;6025	ext4_fsblk_t cmp1, cmp2;6026	struct ext4_map_blocks map;6027 6028	/* Determin the size of the file first */6029	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,6030					EXT4_EX_NOCACHE);6031	if (IS_ERR(path))6032		return PTR_ERR(path);6033	ex = path[path->p_depth].p_ext;6034	if (!ex)6035		goto out;6036	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);6037 6038	/* Count the number of data blocks */6039	cur = 0;6040	while (cur < end) {6041		map.m_lblk = cur;6042		map.m_len = end - cur;6043		ret = ext4_map_blocks(NULL, inode, &map, 0);6044		if (ret < 0)6045			break;6046		if (ret > 0)6047			numblks += ret;6048		cur = cur + map.m_len;6049	}6050 6051	/*6052	 * Count the number of extent tree blocks. We do it by looking up6053	 * two successive extents and determining the difference between6054	 * their paths. When path is different for 2 successive extents6055	 * we compare the blocks in the path at each level and increment6056	 * iblocks by total number of differences found.6057	 */6058	cur = 0;6059	ret = skip_hole(inode, &cur);6060	if (ret < 0)6061		goto out;6062	path = ext4_find_extent(inode, cur, path, 0);6063	if (IS_ERR(path))6064		goto out;6065	numblks += path->p_depth;6066	while (cur < end) {6067		path = ext4_find_extent(inode, cur, path, 0);6068		if (IS_ERR(path))6069			break;6070		ex = path[path->p_depth].p_ext;6071		if (!ex)6072			goto cleanup;6073 6074		cur = max(cur + 1, le32_to_cpu(ex->ee_block) +6075					ext4_ext_get_actual_len(ex));6076		ret = skip_hole(inode, &cur);6077		if (ret < 0)6078			break;6079 6080		path2 = ext4_find_extent(inode, cur, path2, 0);6081		if (IS_ERR(path2))6082			break;6083 6084		for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {6085			cmp1 = cmp2 = 0;6086			if (i <= path->p_depth)6087				cmp1 = path[i].p_bh ?6088					path[i].p_bh->b_blocknr : 0;6089			if (i <= path2->p_depth)6090				cmp2 = path2[i].p_bh ?6091					path2[i].p_bh->b_blocknr : 0;6092			if (cmp1 != cmp2 && cmp2 != 0)6093				numblks++;6094		}6095	}6096 6097out:6098	inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);6099	ext4_mark_inode_dirty(NULL, inode);6100cleanup:6101	ext4_free_ext_path(path);6102	ext4_free_ext_path(path2);6103	return 0;6104}6105 6106int ext4_ext_clear_bb(struct inode *inode)6107{6108	struct ext4_ext_path *path = NULL;6109	struct ext4_extent *ex;6110	ext4_lblk_t cur = 0, end;6111	int j, ret = 0;6112	struct ext4_map_blocks map;6113 6114	if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))6115		return 0;6116 6117	/* Determin the size of the file first */6118	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,6119					EXT4_EX_NOCACHE);6120	if (IS_ERR(path))6121		return PTR_ERR(path);6122	ex = path[path->p_depth].p_ext;6123	if (!ex)6124		goto out;6125	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);6126 6127	cur = 0;6128	while (cur < end) {6129		map.m_lblk = cur;6130		map.m_len = end - cur;6131		ret = ext4_map_blocks(NULL, inode, &map, 0);6132		if (ret < 0)6133			break;6134		if (ret > 0) {6135			path = ext4_find_extent(inode, map.m_lblk, path, 0);6136			if (!IS_ERR(path)) {6137				for (j = 0; j < path->p_depth; j++) {6138					ext4_mb_mark_bb(inode->i_sb,6139							path[j].p_block, 1, false);6140					ext4_fc_record_regions(inode->i_sb, inode->i_ino,6141							0, path[j].p_block, 1, 1);6142				}6143			} else {6144				path = NULL;6145			}6146			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, false);6147			ext4_fc_record_regions(inode->i_sb, inode->i_ino,6148					map.m_lblk, map.m_pblk, map.m_len, 1);6149		}6150		cur = cur + map.m_len;6151	}6152 6153out:6154	ext4_free_ext_path(path);6155	return 0;6156}6157