2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
5 * Architecture independence:
6 * Copyright (c) 2005, Bull S.A.
7 * Written by Pierre Peiffer <pierre.peiffer@bull.net>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public Licens
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
24 * Extents support for EXT4
27 * - ext4*_error() should be used in some situations
28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
29 * - smart tree reduction
32 #include <linux/module.h>
34 #include <linux/time.h>
35 #include <linux/ext4_jbd2.h>
36 #include <linux/jbd2.h>
37 #include <linux/highuid.h>
38 #include <linux/pagemap.h>
39 #include <linux/quotaops.h>
40 #include <linux/string.h>
41 #include <linux/slab.h>
42 #include <linux/falloc.h>
43 #include <linux/ext4_fs_extents.h>
44 #include <asm/uaccess.h>
49 * combine low and high parts of physical block number into ext4_fsblk_t
51 static ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
55 block = le32_to_cpu(ex->ee_start_lo);
56 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
62 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
64 ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
68 block = le32_to_cpu(ix->ei_leaf_lo);
69 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
74 * ext4_ext_store_pblock:
75 * stores a large physical block number into an extent struct,
76 * breaking it into parts
78 void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
80 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
81 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
85 * ext4_idx_store_pblock:
86 * stores a large physical block number into an index struct,
87 * breaking it into parts
89 static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
91 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
92 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
95 static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
99 if (handle->h_buffer_credits > needed)
101 if (!ext4_journal_extend(handle, needed))
103 err = ext4_journal_restart(handle, needed);
113 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
114 struct ext4_ext_path *path)
117 /* path points to block */
118 return ext4_journal_get_write_access(handle, path->p_bh);
120 /* path points to leaf/index in inode body */
121 /* we use in-core data, no need to protect them */
131 static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
132 struct ext4_ext_path *path)
136 /* path points to block */
137 err = ext4_journal_dirty_metadata(handle, path->p_bh);
139 /* path points to leaf/index in inode body */
140 err = ext4_mark_inode_dirty(handle, inode);
145 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
146 struct ext4_ext_path *path,
149 struct ext4_inode_info *ei = EXT4_I(inode);
150 ext4_fsblk_t bg_start;
151 ext4_grpblk_t colour;
155 struct ext4_extent *ex;
156 depth = path->p_depth;
158 /* try to predict block placement */
159 ex = path[depth].p_ext;
161 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
163 /* it looks like index is empty;
164 * try to find starting block from index itself */
165 if (path[depth].p_bh)
166 return path[depth].p_bh->b_blocknr;
169 /* OK. use inode's group */
170 bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
171 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
172 colour = (current->pid % 16) *
173 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
174 return bg_start + colour + block;
178 ext4_ext_new_block(handle_t *handle, struct inode *inode,
179 struct ext4_ext_path *path,
180 struct ext4_extent *ex, int *err)
182 ext4_fsblk_t goal, newblock;
184 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
185 newblock = ext4_new_block(handle, inode, goal, err);
189 static int ext4_ext_space_block(struct inode *inode)
193 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
194 / sizeof(struct ext4_extent);
195 #ifdef AGGRESSIVE_TEST
202 static int ext4_ext_space_block_idx(struct inode *inode)
206 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
207 / sizeof(struct ext4_extent_idx);
208 #ifdef AGGRESSIVE_TEST
215 static int ext4_ext_space_root(struct inode *inode)
219 size = sizeof(EXT4_I(inode)->i_data);
220 size -= sizeof(struct ext4_extent_header);
221 size /= sizeof(struct ext4_extent);
222 #ifdef AGGRESSIVE_TEST
229 static int ext4_ext_space_root_idx(struct inode *inode)
233 size = sizeof(EXT4_I(inode)->i_data);
234 size -= sizeof(struct ext4_extent_header);
235 size /= sizeof(struct ext4_extent_idx);
236 #ifdef AGGRESSIVE_TEST
244 ext4_ext_max_entries(struct inode *inode, int depth)
248 if (depth == ext_depth(inode)) {
250 max = ext4_ext_space_root(inode);
252 max = ext4_ext_space_root_idx(inode);
255 max = ext4_ext_space_block(inode);
257 max = ext4_ext_space_block_idx(inode);
263 static int __ext4_ext_check_header(const char *function, struct inode *inode,
264 struct ext4_extent_header *eh,
267 const char *error_msg;
270 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
271 error_msg = "invalid magic";
274 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
275 error_msg = "unexpected eh_depth";
278 if (unlikely(eh->eh_max == 0)) {
279 error_msg = "invalid eh_max";
282 max = ext4_ext_max_entries(inode, depth);
283 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
284 error_msg = "too large eh_max";
287 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
288 error_msg = "invalid eh_entries";
294 ext4_error(inode->i_sb, function,
295 "bad header in inode #%lu: %s - magic %x, "
296 "entries %u, max %u(%u), depth %u(%u)",
297 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
298 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
299 max, le16_to_cpu(eh->eh_depth), depth);
304 #define ext4_ext_check_header(inode, eh, depth) \
305 __ext4_ext_check_header(__FUNCTION__, inode, eh, depth)
308 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
310 int k, l = path->p_depth;
313 for (k = 0; k <= l; k++, path++) {
315 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
316 idx_pblock(path->p_idx));
317 } else if (path->p_ext) {
318 ext_debug(" %d:%d:%llu ",
319 le32_to_cpu(path->p_ext->ee_block),
320 ext4_ext_get_actual_len(path->p_ext),
321 ext_pblock(path->p_ext));
328 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
330 int depth = ext_depth(inode);
331 struct ext4_extent_header *eh;
332 struct ext4_extent *ex;
338 eh = path[depth].p_hdr;
339 ex = EXT_FIRST_EXTENT(eh);
341 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
342 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
343 ext4_ext_get_actual_len(ex), ext_pblock(ex));
348 #define ext4_ext_show_path(inode,path)
349 #define ext4_ext_show_leaf(inode,path)
352 static void ext4_ext_drop_refs(struct ext4_ext_path *path)
354 int depth = path->p_depth;
357 for (i = 0; i <= depth; i++, path++)
365 * ext4_ext_binsearch_idx:
366 * binary search for the closest index of the given block
367 * the header must be checked before calling this
370 ext4_ext_binsearch_idx(struct inode *inode,
371 struct ext4_ext_path *path, ext4_lblk_t block)
373 struct ext4_extent_header *eh = path->p_hdr;
374 struct ext4_extent_idx *r, *l, *m;
377 ext_debug("binsearch for %u(idx): ", block);
379 l = EXT_FIRST_INDEX(eh) + 1;
380 r = EXT_LAST_INDEX(eh);
383 if (block < le32_to_cpu(m->ei_block))
387 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
388 m, le32_to_cpu(m->ei_block),
389 r, le32_to_cpu(r->ei_block));
393 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
394 idx_pblock(path->p_idx));
396 #ifdef CHECK_BINSEARCH
398 struct ext4_extent_idx *chix, *ix;
401 chix = ix = EXT_FIRST_INDEX(eh);
402 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
404 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
405 printk("k=%d, ix=0x%p, first=0x%p\n", k,
406 ix, EXT_FIRST_INDEX(eh));
408 le32_to_cpu(ix->ei_block),
409 le32_to_cpu(ix[-1].ei_block));
411 BUG_ON(k && le32_to_cpu(ix->ei_block)
412 <= le32_to_cpu(ix[-1].ei_block));
413 if (block < le32_to_cpu(ix->ei_block))
417 BUG_ON(chix != path->p_idx);
424 * ext4_ext_binsearch:
425 * binary search for closest extent of the given block
426 * the header must be checked before calling this
429 ext4_ext_binsearch(struct inode *inode,
430 struct ext4_ext_path *path, ext4_lblk_t block)
432 struct ext4_extent_header *eh = path->p_hdr;
433 struct ext4_extent *r, *l, *m;
435 if (eh->eh_entries == 0) {
437 * this leaf is empty:
438 * we get such a leaf in split/add case
443 ext_debug("binsearch for %u: ", block);
445 l = EXT_FIRST_EXTENT(eh) + 1;
446 r = EXT_LAST_EXTENT(eh);
450 if (block < le32_to_cpu(m->ee_block))
454 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
455 m, le32_to_cpu(m->ee_block),
456 r, le32_to_cpu(r->ee_block));
460 ext_debug(" -> %d:%llu:%d ",
461 le32_to_cpu(path->p_ext->ee_block),
462 ext_pblock(path->p_ext),
463 ext4_ext_get_actual_len(path->p_ext));
465 #ifdef CHECK_BINSEARCH
467 struct ext4_extent *chex, *ex;
470 chex = ex = EXT_FIRST_EXTENT(eh);
471 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
472 BUG_ON(k && le32_to_cpu(ex->ee_block)
473 <= le32_to_cpu(ex[-1].ee_block));
474 if (block < le32_to_cpu(ex->ee_block))
478 BUG_ON(chex != path->p_ext);
484 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
486 struct ext4_extent_header *eh;
488 eh = ext_inode_hdr(inode);
491 eh->eh_magic = EXT4_EXT_MAGIC;
492 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
493 ext4_mark_inode_dirty(handle, inode);
494 ext4_ext_invalidate_cache(inode);
498 struct ext4_ext_path *
499 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
500 struct ext4_ext_path *path)
502 struct ext4_extent_header *eh;
503 struct buffer_head *bh;
504 short int depth, i, ppos = 0, alloc = 0;
506 eh = ext_inode_hdr(inode);
507 depth = ext_depth(inode);
508 if (ext4_ext_check_header(inode, eh, depth))
509 return ERR_PTR(-EIO);
512 /* account possible depth increase */
514 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
517 return ERR_PTR(-ENOMEM);
523 /* walk through the tree */
525 ext_debug("depth %d: num %d, max %d\n",
526 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
528 ext4_ext_binsearch_idx(inode, path + ppos, block);
529 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
530 path[ppos].p_depth = i;
531 path[ppos].p_ext = NULL;
533 bh = sb_bread(inode->i_sb, path[ppos].p_block);
537 eh = ext_block_hdr(bh);
539 BUG_ON(ppos > depth);
540 path[ppos].p_bh = bh;
541 path[ppos].p_hdr = eh;
544 if (ext4_ext_check_header(inode, eh, i))
548 path[ppos].p_depth = i;
549 path[ppos].p_hdr = eh;
550 path[ppos].p_ext = NULL;
551 path[ppos].p_idx = NULL;
554 ext4_ext_binsearch(inode, path + ppos, block);
556 ext4_ext_show_path(inode, path);
561 ext4_ext_drop_refs(path);
564 return ERR_PTR(-EIO);
568 * ext4_ext_insert_index:
569 * insert new index [@logical;@ptr] into the block at @curp;
570 * check where to insert: before @curp or after @curp
572 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
573 struct ext4_ext_path *curp,
574 int logical, ext4_fsblk_t ptr)
576 struct ext4_extent_idx *ix;
579 err = ext4_ext_get_access(handle, inode, curp);
583 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
584 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
585 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
587 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
588 len = (len - 1) * sizeof(struct ext4_extent_idx);
589 len = len < 0 ? 0 : len;
590 ext_debug("insert new index %d after: %llu. "
591 "move %d from 0x%p to 0x%p\n",
593 (curp->p_idx + 1), (curp->p_idx + 2));
594 memmove(curp->p_idx + 2, curp->p_idx + 1, len);
596 ix = curp->p_idx + 1;
599 len = len * sizeof(struct ext4_extent_idx);
600 len = len < 0 ? 0 : len;
601 ext_debug("insert new index %d before: %llu. "
602 "move %d from 0x%p to 0x%p\n",
604 curp->p_idx, (curp->p_idx + 1));
605 memmove(curp->p_idx + 1, curp->p_idx, len);
609 ix->ei_block = cpu_to_le32(logical);
610 ext4_idx_store_pblock(ix, ptr);
611 curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
613 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
614 > le16_to_cpu(curp->p_hdr->eh_max));
615 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
617 err = ext4_ext_dirty(handle, inode, curp);
618 ext4_std_error(inode->i_sb, err);
625 * inserts new subtree into the path, using free index entry
627 * - allocates all needed blocks (new leaf and all intermediate index blocks)
628 * - makes decision where to split
629 * - moves remaining extents and index entries (right to the split point)
630 * into the newly allocated blocks
631 * - initializes subtree
633 static int ext4_ext_split(handle_t *handle, struct inode *inode,
634 struct ext4_ext_path *path,
635 struct ext4_extent *newext, int at)
637 struct buffer_head *bh = NULL;
638 int depth = ext_depth(inode);
639 struct ext4_extent_header *neh;
640 struct ext4_extent_idx *fidx;
641 struct ext4_extent *ex;
643 ext4_fsblk_t newblock, oldblock;
645 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
648 /* make decision: where to split? */
649 /* FIXME: now decision is simplest: at current extent */
651 /* if current leaf will be split, then we should use
652 * border from split point */
653 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
654 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
655 border = path[depth].p_ext[1].ee_block;
656 ext_debug("leaf will be split."
657 " next leaf starts at %d\n",
658 le32_to_cpu(border));
660 border = newext->ee_block;
661 ext_debug("leaf will be added."
662 " next leaf starts at %d\n",
663 le32_to_cpu(border));
667 * If error occurs, then we break processing
668 * and mark filesystem read-only. index won't
669 * be inserted and tree will be in consistent
670 * state. Next mount will repair buffers too.
674 * Get array to track all allocated blocks.
675 * We need this to handle errors and free blocks
678 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
682 /* allocate all needed blocks */
683 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
684 for (a = 0; a < depth - at; a++) {
685 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
688 ablocks[a] = newblock;
691 /* initialize new leaf */
692 newblock = ablocks[--a];
693 BUG_ON(newblock == 0);
694 bh = sb_getblk(inode->i_sb, newblock);
701 err = ext4_journal_get_create_access(handle, bh);
705 neh = ext_block_hdr(bh);
707 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
708 neh->eh_magic = EXT4_EXT_MAGIC;
710 ex = EXT_FIRST_EXTENT(neh);
712 /* move remainder of path[depth] to the new leaf */
713 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
714 /* start copy from next extent */
715 /* TODO: we could do it by single memmove */
718 while (path[depth].p_ext <=
719 EXT_MAX_EXTENT(path[depth].p_hdr)) {
720 ext_debug("move %d:%llu:%d in new leaf %llu\n",
721 le32_to_cpu(path[depth].p_ext->ee_block),
722 ext_pblock(path[depth].p_ext),
723 ext4_ext_get_actual_len(path[depth].p_ext),
725 /*memmove(ex++, path[depth].p_ext++,
726 sizeof(struct ext4_extent));
732 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
733 neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
736 set_buffer_uptodate(bh);
739 err = ext4_journal_dirty_metadata(handle, bh);
745 /* correct old leaf */
747 err = ext4_ext_get_access(handle, inode, path + depth);
750 path[depth].p_hdr->eh_entries =
751 cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
752 err = ext4_ext_dirty(handle, inode, path + depth);
758 /* create intermediate indexes */
762 ext_debug("create %d intermediate indices\n", k);
763 /* insert new index into current index block */
764 /* current depth stored in i var */
768 newblock = ablocks[--a];
769 bh = sb_getblk(inode->i_sb, newblock);
776 err = ext4_journal_get_create_access(handle, bh);
780 neh = ext_block_hdr(bh);
781 neh->eh_entries = cpu_to_le16(1);
782 neh->eh_magic = EXT4_EXT_MAGIC;
783 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
784 neh->eh_depth = cpu_to_le16(depth - i);
785 fidx = EXT_FIRST_INDEX(neh);
786 fidx->ei_block = border;
787 ext4_idx_store_pblock(fidx, oldblock);
789 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
790 i, newblock, le32_to_cpu(border), oldblock);
795 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
796 EXT_MAX_INDEX(path[i].p_hdr));
797 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
798 EXT_LAST_INDEX(path[i].p_hdr));
799 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
800 ext_debug("%d: move %d:%llu in new index %llu\n", i,
801 le32_to_cpu(path[i].p_idx->ei_block),
802 idx_pblock(path[i].p_idx),
804 /*memmove(++fidx, path[i].p_idx++,
805 sizeof(struct ext4_extent_idx));
807 BUG_ON(neh->eh_entries > neh->eh_max);*/
812 memmove(++fidx, path[i].p_idx - m,
813 sizeof(struct ext4_extent_idx) * m);
815 cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
817 set_buffer_uptodate(bh);
820 err = ext4_journal_dirty_metadata(handle, bh);
826 /* correct old index */
828 err = ext4_ext_get_access(handle, inode, path + i);
831 path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
832 err = ext4_ext_dirty(handle, inode, path + i);
840 /* insert new index */
841 err = ext4_ext_insert_index(handle, inode, path + at,
842 le32_to_cpu(border), newblock);
846 if (buffer_locked(bh))
852 /* free all allocated blocks in error case */
853 for (i = 0; i < depth; i++) {
856 ext4_free_blocks(handle, inode, ablocks[i], 1, 1);
865 * ext4_ext_grow_indepth:
866 * implements tree growing procedure:
867 * - allocates new block
868 * - moves top-level data (index block or leaf) into the new block
869 * - initializes new top-level, creating index that points to the
872 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
873 struct ext4_ext_path *path,
874 struct ext4_extent *newext)
876 struct ext4_ext_path *curp = path;
877 struct ext4_extent_header *neh;
878 struct ext4_extent_idx *fidx;
879 struct buffer_head *bh;
880 ext4_fsblk_t newblock;
883 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
887 bh = sb_getblk(inode->i_sb, newblock);
890 ext4_std_error(inode->i_sb, err);
895 err = ext4_journal_get_create_access(handle, bh);
901 /* move top-level index/leaf into new block */
902 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
904 /* set size of new block */
905 neh = ext_block_hdr(bh);
906 /* old root could have indexes or leaves
907 * so calculate e_max right way */
908 if (ext_depth(inode))
909 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
911 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
912 neh->eh_magic = EXT4_EXT_MAGIC;
913 set_buffer_uptodate(bh);
916 err = ext4_journal_dirty_metadata(handle, bh);
920 /* create index in new top-level index: num,max,pointer */
921 err = ext4_ext_get_access(handle, inode, curp);
925 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
926 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
927 curp->p_hdr->eh_entries = cpu_to_le16(1);
928 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
930 if (path[0].p_hdr->eh_depth)
931 curp->p_idx->ei_block =
932 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
934 curp->p_idx->ei_block =
935 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
936 ext4_idx_store_pblock(curp->p_idx, newblock);
938 neh = ext_inode_hdr(inode);
939 fidx = EXT_FIRST_INDEX(neh);
940 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
941 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
942 le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
944 neh->eh_depth = cpu_to_le16(path->p_depth + 1);
945 err = ext4_ext_dirty(handle, inode, curp);
953 * ext4_ext_create_new_leaf:
954 * finds empty index and adds new leaf.
955 * if no free index is found, then it requests in-depth growing.
957 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
958 struct ext4_ext_path *path,
959 struct ext4_extent *newext)
961 struct ext4_ext_path *curp;
962 int depth, i, err = 0;
965 i = depth = ext_depth(inode);
967 /* walk up to the tree and look for free index entry */
969 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
974 /* we use already allocated block for index block,
975 * so subsequent data blocks should be contiguous */
976 if (EXT_HAS_FREE_INDEX(curp)) {
977 /* if we found index with free entry, then use that
978 * entry: create all needed subtree and add new leaf */
979 err = ext4_ext_split(handle, inode, path, newext, i);
982 ext4_ext_drop_refs(path);
983 path = ext4_ext_find_extent(inode,
984 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
989 /* tree is full, time to grow in depth */
990 err = ext4_ext_grow_indepth(handle, inode, path, newext);
995 ext4_ext_drop_refs(path);
996 path = ext4_ext_find_extent(inode,
997 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1000 err = PTR_ERR(path);
1005 * only first (depth 0 -> 1) produces free space;
1006 * in all other cases we have to split the grown tree
1008 depth = ext_depth(inode);
1009 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1010 /* now we need to split */
1020 * search the closest allocated block to the left for *logical
1021 * and returns it at @logical + it's physical address at @phys
1022 * if *logical is the smallest allocated block, the function
1023 * returns 0 at @phys
1024 * return value contains 0 (success) or error code
1027 ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path,
1028 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1030 struct ext4_extent_idx *ix;
1031 struct ext4_extent *ex;
1034 BUG_ON(path == NULL);
1035 depth = path->p_depth;
1038 if (depth == 0 && path->p_ext == NULL)
1041 /* usually extent in the path covers blocks smaller
1042 * then *logical, but it can be that extent is the
1043 * first one in the file */
1045 ex = path[depth].p_ext;
1046 ee_len = ext4_ext_get_actual_len(ex);
1047 if (*logical < le32_to_cpu(ex->ee_block)) {
1048 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex);
1049 while (--depth >= 0) {
1050 ix = path[depth].p_idx;
1051 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr));
1056 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len));
1058 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1059 *phys = ext_pblock(ex) + ee_len - 1;
1064 * search the closest allocated block to the right for *logical
1065 * and returns it at @logical + it's physical address at @phys
1066 * if *logical is the smallest allocated block, the function
1067 * returns 0 at @phys
1068 * return value contains 0 (success) or error code
1071 ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path,
1072 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1074 struct buffer_head *bh = NULL;
1075 struct ext4_extent_header *eh;
1076 struct ext4_extent_idx *ix;
1077 struct ext4_extent *ex;
1081 BUG_ON(path == NULL);
1082 depth = path->p_depth;
1085 if (depth == 0 && path->p_ext == NULL)
1088 /* usually extent in the path covers blocks smaller
1089 * then *logical, but it can be that extent is the
1090 * first one in the file */
1092 ex = path[depth].p_ext;
1093 ee_len = ext4_ext_get_actual_len(ex);
1094 if (*logical < le32_to_cpu(ex->ee_block)) {
1095 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex);
1096 while (--depth >= 0) {
1097 ix = path[depth].p_idx;
1098 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr));
1100 *logical = le32_to_cpu(ex->ee_block);
1101 *phys = ext_pblock(ex);
1105 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len));
1107 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1108 /* next allocated block in this leaf */
1110 *logical = le32_to_cpu(ex->ee_block);
1111 *phys = ext_pblock(ex);
1115 /* go up and search for index to the right */
1116 while (--depth >= 0) {
1117 ix = path[depth].p_idx;
1118 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1123 /* we've gone up to the root and
1124 * found no index to the right */
1128 /* we've found index to the right, let's
1129 * follow it and find the closest allocated
1130 * block to the right */
1132 block = idx_pblock(ix);
1133 while (++depth < path->p_depth) {
1134 bh = sb_bread(inode->i_sb, block);
1137 eh = ext_block_hdr(bh);
1138 if (ext4_ext_check_header(inode, eh, depth)) {
1142 ix = EXT_FIRST_INDEX(eh);
1143 block = idx_pblock(ix);
1147 bh = sb_bread(inode->i_sb, block);
1150 eh = ext_block_hdr(bh);
1151 if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) {
1155 ex = EXT_FIRST_EXTENT(eh);
1156 *logical = le32_to_cpu(ex->ee_block);
1157 *phys = ext_pblock(ex);
1164 * ext4_ext_next_allocated_block:
1165 * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
1166 * NOTE: it considers block number from index entry as
1167 * allocated block. Thus, index entries have to be consistent
1171 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1175 BUG_ON(path == NULL);
1176 depth = path->p_depth;
1178 if (depth == 0 && path->p_ext == NULL)
1179 return EXT_MAX_BLOCK;
1181 while (depth >= 0) {
1182 if (depth == path->p_depth) {
1184 if (path[depth].p_ext !=
1185 EXT_LAST_EXTENT(path[depth].p_hdr))
1186 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1189 if (path[depth].p_idx !=
1190 EXT_LAST_INDEX(path[depth].p_hdr))
1191 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1196 return EXT_MAX_BLOCK;
1200 * ext4_ext_next_leaf_block:
1201 * returns first allocated block from next leaf or EXT_MAX_BLOCK
1203 static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
1204 struct ext4_ext_path *path)
1208 BUG_ON(path == NULL);
1209 depth = path->p_depth;
1211 /* zero-tree has no leaf blocks at all */
1213 return EXT_MAX_BLOCK;
1215 /* go to index block */
1218 while (depth >= 0) {
1219 if (path[depth].p_idx !=
1220 EXT_LAST_INDEX(path[depth].p_hdr))
1221 return (ext4_lblk_t)
1222 le32_to_cpu(path[depth].p_idx[1].ei_block);
1226 return EXT_MAX_BLOCK;
1230 * ext4_ext_correct_indexes:
1231 * if leaf gets modified and modified extent is first in the leaf,
1232 * then we have to correct all indexes above.
1233 * TODO: do we need to correct tree in all cases?
1235 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1236 struct ext4_ext_path *path)
1238 struct ext4_extent_header *eh;
1239 int depth = ext_depth(inode);
1240 struct ext4_extent *ex;
1244 eh = path[depth].p_hdr;
1245 ex = path[depth].p_ext;
1250 /* there is no tree at all */
1254 if (ex != EXT_FIRST_EXTENT(eh)) {
1255 /* we correct tree if first leaf got modified only */
1260 * TODO: we need correction if border is smaller than current one
1263 border = path[depth].p_ext->ee_block;
1264 err = ext4_ext_get_access(handle, inode, path + k);
1267 path[k].p_idx->ei_block = border;
1268 err = ext4_ext_dirty(handle, inode, path + k);
1273 /* change all left-side indexes */
1274 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1276 err = ext4_ext_get_access(handle, inode, path + k);
1279 path[k].p_idx->ei_block = border;
1280 err = ext4_ext_dirty(handle, inode, path + k);
1289 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1290 struct ext4_extent *ex2)
1292 unsigned short ext1_ee_len, ext2_ee_len, max_len;
1295 * Make sure that either both extents are uninitialized, or
1298 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1301 if (ext4_ext_is_uninitialized(ex1))
1302 max_len = EXT_UNINIT_MAX_LEN;
1304 max_len = EXT_INIT_MAX_LEN;
1306 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1307 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1309 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1310 le32_to_cpu(ex2->ee_block))
1314 * To allow future support for preallocated extents to be added
1315 * as an RO_COMPAT feature, refuse to merge to extents if
1316 * this can result in the top bit of ee_len being set.
1318 if (ext1_ee_len + ext2_ee_len > max_len)
1320 #ifdef AGGRESSIVE_TEST
1321 if (ext1_ee_len >= 4)
1325 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
1331 * This function tries to merge the "ex" extent to the next extent in the tree.
1332 * It always tries to merge towards right. If you want to merge towards
1333 * left, pass "ex - 1" as argument instead of "ex".
1334 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1335 * 1 if they got merged.
1337 int ext4_ext_try_to_merge(struct inode *inode,
1338 struct ext4_ext_path *path,
1339 struct ext4_extent *ex)
1341 struct ext4_extent_header *eh;
1342 unsigned int depth, len;
1344 int uninitialized = 0;
1346 depth = ext_depth(inode);
1347 BUG_ON(path[depth].p_hdr == NULL);
1348 eh = path[depth].p_hdr;
1350 while (ex < EXT_LAST_EXTENT(eh)) {
1351 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1353 /* merge with next extent! */
1354 if (ext4_ext_is_uninitialized(ex))
1356 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1357 + ext4_ext_get_actual_len(ex + 1));
1359 ext4_ext_mark_uninitialized(ex);
1361 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1362 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1363 * sizeof(struct ext4_extent);
1364 memmove(ex + 1, ex + 2, len);
1366 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries) - 1);
1368 WARN_ON(eh->eh_entries == 0);
1369 if (!eh->eh_entries)
1370 ext4_error(inode->i_sb, "ext4_ext_try_to_merge",
1371 "inode#%lu, eh->eh_entries = 0!", inode->i_ino);
1378 * check if a portion of the "newext" extent overlaps with an
1381 * If there is an overlap discovered, it updates the length of the newext
1382 * such that there will be no overlap, and then returns 1.
1383 * If there is no overlap found, it returns 0.
1385 unsigned int ext4_ext_check_overlap(struct inode *inode,
1386 struct ext4_extent *newext,
1387 struct ext4_ext_path *path)
1390 unsigned int depth, len1;
1391 unsigned int ret = 0;
1393 b1 = le32_to_cpu(newext->ee_block);
1394 len1 = ext4_ext_get_actual_len(newext);
1395 depth = ext_depth(inode);
1396 if (!path[depth].p_ext)
1398 b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1401 * get the next allocated block if the extent in the path
1402 * is before the requested block(s)
1405 b2 = ext4_ext_next_allocated_block(path);
1406 if (b2 == EXT_MAX_BLOCK)
1410 /* check for wrap through zero on extent logical start block*/
1411 if (b1 + len1 < b1) {
1412 len1 = EXT_MAX_BLOCK - b1;
1413 newext->ee_len = cpu_to_le16(len1);
1417 /* check for overlap */
1418 if (b1 + len1 > b2) {
1419 newext->ee_len = cpu_to_le16(b2 - b1);
1427 * ext4_ext_insert_extent:
1428 * tries to merge requsted extent into the existing extent or
1429 * inserts requested extent as new one into the tree,
1430 * creating new leaf in the no-space case.
1432 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1433 struct ext4_ext_path *path,
1434 struct ext4_extent *newext)
1436 struct ext4_extent_header * eh;
1437 struct ext4_extent *ex, *fex;
1438 struct ext4_extent *nearex; /* nearest extent */
1439 struct ext4_ext_path *npath = NULL;
1440 int depth, len, err;
1442 unsigned uninitialized = 0;
1444 BUG_ON(ext4_ext_get_actual_len(newext) == 0);
1445 depth = ext_depth(inode);
1446 ex = path[depth].p_ext;
1447 BUG_ON(path[depth].p_hdr == NULL);
1449 /* try to insert block into found extent and return */
1450 if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
1451 ext_debug("append %d block to %d:%d (from %llu)\n",
1452 ext4_ext_get_actual_len(newext),
1453 le32_to_cpu(ex->ee_block),
1454 ext4_ext_get_actual_len(ex), ext_pblock(ex));
1455 err = ext4_ext_get_access(handle, inode, path + depth);
1460 * ext4_can_extents_be_merged should have checked that either
1461 * both extents are uninitialized, or both aren't. Thus we
1462 * need to check only one of them here.
1464 if (ext4_ext_is_uninitialized(ex))
1466 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1467 + ext4_ext_get_actual_len(newext));
1469 ext4_ext_mark_uninitialized(ex);
1470 eh = path[depth].p_hdr;
1476 depth = ext_depth(inode);
1477 eh = path[depth].p_hdr;
1478 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1481 /* probably next leaf has space for us? */
1482 fex = EXT_LAST_EXTENT(eh);
1483 next = ext4_ext_next_leaf_block(inode, path);
1484 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1485 && next != EXT_MAX_BLOCK) {
1486 ext_debug("next leaf block - %d\n", next);
1487 BUG_ON(npath != NULL);
1488 npath = ext4_ext_find_extent(inode, next, NULL);
1490 return PTR_ERR(npath);
1491 BUG_ON(npath->p_depth != path->p_depth);
1492 eh = npath[depth].p_hdr;
1493 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1494 ext_debug("next leaf isnt full(%d)\n",
1495 le16_to_cpu(eh->eh_entries));
1499 ext_debug("next leaf has no free space(%d,%d)\n",
1500 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1504 * There is no free space in the found leaf.
1505 * We're gonna add a new leaf in the tree.
1507 err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1510 depth = ext_depth(inode);
1511 eh = path[depth].p_hdr;
1514 nearex = path[depth].p_ext;
1516 err = ext4_ext_get_access(handle, inode, path + depth);
1521 /* there is no extent in this leaf, create first one */
1522 ext_debug("first extent in the leaf: %d:%llu:%d\n",
1523 le32_to_cpu(newext->ee_block),
1525 ext4_ext_get_actual_len(newext));
1526 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1527 } else if (le32_to_cpu(newext->ee_block)
1528 > le32_to_cpu(nearex->ee_block)) {
1529 /* BUG_ON(newext->ee_block == nearex->ee_block); */
1530 if (nearex != EXT_LAST_EXTENT(eh)) {
1531 len = EXT_MAX_EXTENT(eh) - nearex;
1532 len = (len - 1) * sizeof(struct ext4_extent);
1533 len = len < 0 ? 0 : len;
1534 ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
1535 "move %d from 0x%p to 0x%p\n",
1536 le32_to_cpu(newext->ee_block),
1538 ext4_ext_get_actual_len(newext),
1539 nearex, len, nearex + 1, nearex + 2);
1540 memmove(nearex + 2, nearex + 1, len);
1542 path[depth].p_ext = nearex + 1;
1544 BUG_ON(newext->ee_block == nearex->ee_block);
1545 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1546 len = len < 0 ? 0 : len;
1547 ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
1548 "move %d from 0x%p to 0x%p\n",
1549 le32_to_cpu(newext->ee_block),
1551 ext4_ext_get_actual_len(newext),
1552 nearex, len, nearex + 1, nearex + 2);
1553 memmove(nearex + 1, nearex, len);
1554 path[depth].p_ext = nearex;
1557 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
1558 nearex = path[depth].p_ext;
1559 nearex->ee_block = newext->ee_block;
1560 ext4_ext_store_pblock(nearex, ext_pblock(newext));
1561 nearex->ee_len = newext->ee_len;
1564 /* try to merge extents to the right */
1565 ext4_ext_try_to_merge(inode, path, nearex);
1567 /* try to merge extents to the left */
1569 /* time to correct all indexes above */
1570 err = ext4_ext_correct_indexes(handle, inode, path);
1574 err = ext4_ext_dirty(handle, inode, path + depth);
1578 ext4_ext_drop_refs(npath);
1581 ext4_ext_tree_changed(inode);
1582 ext4_ext_invalidate_cache(inode);
1587 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1588 __u32 len, ext4_fsblk_t start, int type)
1590 struct ext4_ext_cache *cex;
1592 cex = &EXT4_I(inode)->i_cached_extent;
1593 cex->ec_type = type;
1594 cex->ec_block = block;
1596 cex->ec_start = start;
1600 * ext4_ext_put_gap_in_cache:
1601 * calculate boundaries of the gap that the requested block fits into
1602 * and cache this gap
1605 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1608 int depth = ext_depth(inode);
1611 struct ext4_extent *ex;
1613 ex = path[depth].p_ext;
1615 /* there is no extent yet, so gap is [0;-] */
1617 len = EXT_MAX_BLOCK;
1618 ext_debug("cache gap(whole file):");
1619 } else if (block < le32_to_cpu(ex->ee_block)) {
1621 len = le32_to_cpu(ex->ee_block) - block;
1622 ext_debug("cache gap(before): %u [%u:%u]",
1624 le32_to_cpu(ex->ee_block),
1625 ext4_ext_get_actual_len(ex));
1626 } else if (block >= le32_to_cpu(ex->ee_block)
1627 + ext4_ext_get_actual_len(ex)) {
1629 lblock = le32_to_cpu(ex->ee_block)
1630 + ext4_ext_get_actual_len(ex);
1632 next = ext4_ext_next_allocated_block(path);
1633 ext_debug("cache gap(after): [%u:%u] %u",
1634 le32_to_cpu(ex->ee_block),
1635 ext4_ext_get_actual_len(ex),
1637 BUG_ON(next == lblock);
1638 len = next - lblock;
1644 ext_debug(" -> %u:%lu\n", lblock, len);
1645 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1649 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
1650 struct ext4_extent *ex)
1652 struct ext4_ext_cache *cex;
1654 cex = &EXT4_I(inode)->i_cached_extent;
1656 /* has cache valid data? */
1657 if (cex->ec_type == EXT4_EXT_CACHE_NO)
1658 return EXT4_EXT_CACHE_NO;
1660 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1661 cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1662 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
1663 ex->ee_block = cpu_to_le32(cex->ec_block);
1664 ext4_ext_store_pblock(ex, cex->ec_start);
1665 ex->ee_len = cpu_to_le16(cex->ec_len);
1666 ext_debug("%u cached by %u:%u:%llu\n",
1668 cex->ec_block, cex->ec_len, cex->ec_start);
1669 return cex->ec_type;
1673 return EXT4_EXT_CACHE_NO;
1678 * removes index from the index block.
1679 * It's used in truncate case only, thus all requests are for
1680 * last index in the block only.
1682 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1683 struct ext4_ext_path *path)
1685 struct buffer_head *bh;
1689 /* free index block */
1691 leaf = idx_pblock(path->p_idx);
1692 BUG_ON(path->p_hdr->eh_entries == 0);
1693 err = ext4_ext_get_access(handle, inode, path);
1696 path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
1697 err = ext4_ext_dirty(handle, inode, path);
1700 ext_debug("index is empty, remove it, free block %llu\n", leaf);
1701 bh = sb_find_get_block(inode->i_sb, leaf);
1702 ext4_forget(handle, 1, inode, bh, leaf);
1703 ext4_free_blocks(handle, inode, leaf, 1, 1);
1708 * ext4_ext_calc_credits_for_insert:
1709 * This routine returns max. credits that the extent tree can consume.
1710 * It should be OK for low-performance paths like ->writepage()
1711 * To allow many writing processes to fit into a single transaction,
1712 * the caller should calculate credits under i_data_sem and
1713 * pass the actual path.
1715 int ext4_ext_calc_credits_for_insert(struct inode *inode,
1716 struct ext4_ext_path *path)
1721 /* probably there is space in leaf? */
1722 depth = ext_depth(inode);
1723 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1724 < le16_to_cpu(path[depth].p_hdr->eh_max))
1729 * given 32-bit logical block (4294967296 blocks), max. tree
1730 * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
1731 * Let's also add one more level for imbalance.
1735 /* allocation of new data block(s) */
1739 * tree can be full, so it would need to grow in depth:
1740 * we need one credit to modify old root, credits for
1741 * new root will be added in split accounting
1746 * Index split can happen, we would need:
1747 * allocate intermediate indexes (bitmap + group)
1748 * + change two blocks at each level, but root (already included)
1750 needed += (depth * 2) + (depth * 2);
1752 /* any allocation modifies superblock */
1758 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
1759 struct ext4_extent *ex,
1760 ext4_lblk_t from, ext4_lblk_t to)
1762 struct buffer_head *bh;
1763 unsigned short ee_len = ext4_ext_get_actual_len(ex);
1764 int i, metadata = 0;
1766 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
1768 #ifdef EXTENTS_STATS
1770 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1771 spin_lock(&sbi->s_ext_stats_lock);
1772 sbi->s_ext_blocks += ee_len;
1773 sbi->s_ext_extents++;
1774 if (ee_len < sbi->s_ext_min)
1775 sbi->s_ext_min = ee_len;
1776 if (ee_len > sbi->s_ext_max)
1777 sbi->s_ext_max = ee_len;
1778 if (ext_depth(inode) > sbi->s_depth_max)
1779 sbi->s_depth_max = ext_depth(inode);
1780 spin_unlock(&sbi->s_ext_stats_lock);
1783 if (from >= le32_to_cpu(ex->ee_block)
1784 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
1789 num = le32_to_cpu(ex->ee_block) + ee_len - from;
1790 start = ext_pblock(ex) + ee_len - num;
1791 ext_debug("free last %u blocks starting %llu\n", num, start);
1792 for (i = 0; i < num; i++) {
1793 bh = sb_find_get_block(inode->i_sb, start + i);
1794 ext4_forget(handle, 0, inode, bh, start + i);
1796 ext4_free_blocks(handle, inode, start, num, metadata);
1797 } else if (from == le32_to_cpu(ex->ee_block)
1798 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
1799 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n",
1800 from, to, le32_to_cpu(ex->ee_block), ee_len);
1802 printk(KERN_INFO "strange request: removal(2) "
1803 "%u-%u from %u:%u\n",
1804 from, to, le32_to_cpu(ex->ee_block), ee_len);
1810 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
1811 struct ext4_ext_path *path, ext4_lblk_t start)
1813 int err = 0, correct_index = 0;
1814 int depth = ext_depth(inode), credits;
1815 struct ext4_extent_header *eh;
1816 ext4_lblk_t a, b, block;
1818 ext4_lblk_t ex_ee_block;
1819 unsigned short ex_ee_len;
1820 unsigned uninitialized = 0;
1821 struct ext4_extent *ex;
1823 /* the header must be checked already in ext4_ext_remove_space() */
1824 ext_debug("truncate since %u in leaf\n", start);
1825 if (!path[depth].p_hdr)
1826 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
1827 eh = path[depth].p_hdr;
1830 /* find where to start removing */
1831 ex = EXT_LAST_EXTENT(eh);
1833 ex_ee_block = le32_to_cpu(ex->ee_block);
1834 if (ext4_ext_is_uninitialized(ex))
1836 ex_ee_len = ext4_ext_get_actual_len(ex);
1838 while (ex >= EXT_FIRST_EXTENT(eh) &&
1839 ex_ee_block + ex_ee_len > start) {
1840 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
1841 path[depth].p_ext = ex;
1843 a = ex_ee_block > start ? ex_ee_block : start;
1844 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
1845 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
1847 ext_debug(" border %u:%u\n", a, b);
1849 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
1853 } else if (a != ex_ee_block) {
1854 /* remove tail of the extent */
1855 block = ex_ee_block;
1857 } else if (b != ex_ee_block + ex_ee_len - 1) {
1858 /* remove head of the extent */
1861 /* there is no "make a hole" API yet */
1864 /* remove whole extent: excellent! */
1865 block = ex_ee_block;
1867 BUG_ON(a != ex_ee_block);
1868 BUG_ON(b != ex_ee_block + ex_ee_len - 1);
1871 /* at present, extent can't cross block group: */
1872 /* leaf + bitmap + group desc + sb + inode */
1874 if (ex == EXT_FIRST_EXTENT(eh)) {
1876 credits += (ext_depth(inode)) + 1;
1879 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
1882 handle = ext4_ext_journal_restart(handle, credits);
1883 if (IS_ERR(handle)) {
1884 err = PTR_ERR(handle);
1888 err = ext4_ext_get_access(handle, inode, path + depth);
1892 err = ext4_remove_blocks(handle, inode, ex, a, b);
1897 /* this extent is removed; mark slot entirely unused */
1898 ext4_ext_store_pblock(ex, 0);
1899 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1902 ex->ee_block = cpu_to_le32(block);
1903 ex->ee_len = cpu_to_le16(num);
1905 * Do not mark uninitialized if all the blocks in the
1906 * extent have been removed.
1908 if (uninitialized && num)
1909 ext4_ext_mark_uninitialized(ex);
1911 err = ext4_ext_dirty(handle, inode, path + depth);
1915 ext_debug("new extent: %u:%u:%llu\n", block, num,
1918 ex_ee_block = le32_to_cpu(ex->ee_block);
1919 ex_ee_len = ext4_ext_get_actual_len(ex);
1922 if (correct_index && eh->eh_entries)
1923 err = ext4_ext_correct_indexes(handle, inode, path);
1925 /* if this leaf is free, then we should
1926 * remove it from index block above */
1927 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
1928 err = ext4_ext_rm_idx(handle, inode, path + depth);
1935 * ext4_ext_more_to_rm:
1936 * returns 1 if current index has to be freed (even partial)
1939 ext4_ext_more_to_rm(struct ext4_ext_path *path)
1941 BUG_ON(path->p_idx == NULL);
1943 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
1947 * if truncate on deeper level happened, it wasn't partial,
1948 * so we have to consider current index for truncation
1950 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
1955 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
1957 struct super_block *sb = inode->i_sb;
1958 int depth = ext_depth(inode);
1959 struct ext4_ext_path *path;
1963 ext_debug("truncate since %u\n", start);
1965 /* probably first extent we're gonna free will be last in block */
1966 handle = ext4_journal_start(inode, depth + 1);
1968 return PTR_ERR(handle);
1970 ext4_ext_invalidate_cache(inode);
1973 * We start scanning from right side, freeing all the blocks
1974 * after i_size and walking into the tree depth-wise.
1976 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
1978 ext4_journal_stop(handle);
1981 path[0].p_hdr = ext_inode_hdr(inode);
1982 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) {
1986 path[0].p_depth = depth;
1988 while (i >= 0 && err == 0) {
1990 /* this is leaf block */
1991 err = ext4_ext_rm_leaf(handle, inode, path, start);
1992 /* root level has p_bh == NULL, brelse() eats this */
1993 brelse(path[i].p_bh);
1994 path[i].p_bh = NULL;
1999 /* this is index block */
2000 if (!path[i].p_hdr) {
2001 ext_debug("initialize header\n");
2002 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2005 if (!path[i].p_idx) {
2006 /* this level hasn't been touched yet */
2007 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2008 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2009 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2011 le16_to_cpu(path[i].p_hdr->eh_entries));
2013 /* we were already here, see at next index */
2017 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2018 i, EXT_FIRST_INDEX(path[i].p_hdr),
2020 if (ext4_ext_more_to_rm(path + i)) {
2021 struct buffer_head *bh;
2022 /* go to the next level */
2023 ext_debug("move to level %d (block %llu)\n",
2024 i + 1, idx_pblock(path[i].p_idx));
2025 memset(path + i + 1, 0, sizeof(*path));
2026 bh = sb_bread(sb, idx_pblock(path[i].p_idx));
2028 /* should we reset i_size? */
2032 if (WARN_ON(i + 1 > depth)) {
2036 if (ext4_ext_check_header(inode, ext_block_hdr(bh),
2041 path[i + 1].p_bh = bh;
2043 /* save actual number of indexes since this
2044 * number is changed at the next iteration */
2045 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2048 /* we finished processing this index, go up */
2049 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2050 /* index is empty, remove it;
2051 * handle must be already prepared by the
2052 * truncatei_leaf() */
2053 err = ext4_ext_rm_idx(handle, inode, path + i);
2055 /* root level has p_bh == NULL, brelse() eats this */
2056 brelse(path[i].p_bh);
2057 path[i].p_bh = NULL;
2059 ext_debug("return to level %d\n", i);
2063 /* TODO: flexible tree reduction should be here */
2064 if (path->p_hdr->eh_entries == 0) {
2066 * truncate to zero freed all the tree,
2067 * so we need to correct eh_depth
2069 err = ext4_ext_get_access(handle, inode, path);
2071 ext_inode_hdr(inode)->eh_depth = 0;
2072 ext_inode_hdr(inode)->eh_max =
2073 cpu_to_le16(ext4_ext_space_root(inode));
2074 err = ext4_ext_dirty(handle, inode, path);
2078 ext4_ext_tree_changed(inode);
2079 ext4_ext_drop_refs(path);
2081 ext4_journal_stop(handle);
2087 * called at mount time
2089 void ext4_ext_init(struct super_block *sb)
2092 * possible initialization would be here
2095 if (test_opt(sb, EXTENTS)) {
2096 printk("EXT4-fs: file extents enabled");
2097 #ifdef AGGRESSIVE_TEST
2098 printk(", aggressive tests");
2100 #ifdef CHECK_BINSEARCH
2101 printk(", check binsearch");
2103 #ifdef EXTENTS_STATS
2107 #ifdef EXTENTS_STATS
2108 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2109 EXT4_SB(sb)->s_ext_min = 1 << 30;
2110 EXT4_SB(sb)->s_ext_max = 0;
2116 * called at umount time
2118 void ext4_ext_release(struct super_block *sb)
2120 if (!test_opt(sb, EXTENTS))
2123 #ifdef EXTENTS_STATS
2124 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2125 struct ext4_sb_info *sbi = EXT4_SB(sb);
2126 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2127 sbi->s_ext_blocks, sbi->s_ext_extents,
2128 sbi->s_ext_blocks / sbi->s_ext_extents);
2129 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2130 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2136 * This function is called by ext4_ext_get_blocks() if someone tries to write
2137 * to an uninitialized extent. It may result in splitting the uninitialized
2138 * extent into multiple extents (upto three - one initialized and two
2140 * There are three possibilities:
2141 * a> There is no split required: Entire extent should be initialized
2142 * b> Splits in two extents: Write is happening at either end of the extent
2143 * c> Splits in three extents: Somone is writing in middle of the extent
2145 static int ext4_ext_convert_to_initialized(handle_t *handle,
2146 struct inode *inode,
2147 struct ext4_ext_path *path,
2149 unsigned long max_blocks)
2151 struct ext4_extent *ex, newex;
2152 struct ext4_extent *ex1 = NULL;
2153 struct ext4_extent *ex2 = NULL;
2154 struct ext4_extent *ex3 = NULL;
2155 struct ext4_extent_header *eh;
2156 ext4_lblk_t ee_block;
2157 unsigned int allocated, ee_len, depth;
2158 ext4_fsblk_t newblock;
2162 depth = ext_depth(inode);
2163 eh = path[depth].p_hdr;
2164 ex = path[depth].p_ext;
2165 ee_block = le32_to_cpu(ex->ee_block);
2166 ee_len = ext4_ext_get_actual_len(ex);
2167 allocated = ee_len - (iblock - ee_block);
2168 newblock = iblock - ee_block + ext_pblock(ex);
2171 /* ex1: ee_block to iblock - 1 : uninitialized */
2172 if (iblock > ee_block) {
2174 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2175 ext4_ext_mark_uninitialized(ex1);
2179 * for sanity, update the length of the ex2 extent before
2180 * we insert ex3, if ex1 is NULL. This is to avoid temporary
2181 * overlap of blocks.
2183 if (!ex1 && allocated > max_blocks)
2184 ex2->ee_len = cpu_to_le16(max_blocks);
2185 /* ex3: to ee_block + ee_len : uninitialised */
2186 if (allocated > max_blocks) {
2187 unsigned int newdepth;
2189 ex3->ee_block = cpu_to_le32(iblock + max_blocks);
2190 ext4_ext_store_pblock(ex3, newblock + max_blocks);
2191 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
2192 ext4_ext_mark_uninitialized(ex3);
2193 err = ext4_ext_insert_extent(handle, inode, path, ex3);
2197 * The depth, and hence eh & ex might change
2198 * as part of the insert above.
2200 newdepth = ext_depth(inode);
2201 if (newdepth != depth) {
2203 path = ext4_ext_find_extent(inode, iblock, NULL);
2205 err = PTR_ERR(path);
2209 eh = path[depth].p_hdr;
2210 ex = path[depth].p_ext;
2214 allocated = max_blocks;
2217 * If there was a change of depth as part of the
2218 * insertion of ex3 above, we need to update the length
2219 * of the ex1 extent again here
2221 if (ex1 && ex1 != ex) {
2223 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2224 ext4_ext_mark_uninitialized(ex1);
2227 /* ex2: iblock to iblock + maxblocks-1 : initialised */
2228 ex2->ee_block = cpu_to_le32(iblock);
2229 ext4_ext_store_pblock(ex2, newblock);
2230 ex2->ee_len = cpu_to_le16(allocated);
2233 err = ext4_ext_get_access(handle, inode, path + depth);
2237 * New (initialized) extent starts from the first block
2238 * in the current extent. i.e., ex2 == ex
2239 * We have to see if it can be merged with the extent
2242 if (ex2 > EXT_FIRST_EXTENT(eh)) {
2244 * To merge left, pass "ex2 - 1" to try_to_merge(),
2245 * since it merges towards right _only_.
2247 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
2249 err = ext4_ext_correct_indexes(handle, inode, path);
2252 depth = ext_depth(inode);
2257 * Try to Merge towards right. This might be required
2258 * only when the whole extent is being written to.
2259 * i.e. ex2 == ex and ex3 == NULL.
2262 ret = ext4_ext_try_to_merge(inode, path, ex2);
2264 err = ext4_ext_correct_indexes(handle, inode, path);
2269 /* Mark modified extent as dirty */
2270 err = ext4_ext_dirty(handle, inode, path + depth);
2273 err = ext4_ext_insert_extent(handle, inode, path, &newex);
2275 return err ? err : allocated;
2279 * Need to be called with
2280 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
2281 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
2283 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
2285 unsigned long max_blocks, struct buffer_head *bh_result,
2286 int create, int extend_disksize)
2288 struct ext4_ext_path *path = NULL;
2289 struct ext4_extent_header *eh;
2290 struct ext4_extent newex, *ex;
2291 ext4_fsblk_t goal, newblock;
2292 int err = 0, depth, ret;
2293 unsigned long allocated = 0;
2294 struct ext4_allocation_request ar;
2296 __clear_bit(BH_New, &bh_result->b_state);
2297 ext_debug("blocks %u/%lu requested for inode %u\n",
2298 iblock, max_blocks, inode->i_ino);
2300 /* check in cache */
2301 goal = ext4_ext_in_cache(inode, iblock, &newex);
2303 if (goal == EXT4_EXT_CACHE_GAP) {
2306 * block isn't allocated yet and
2307 * user doesn't want to allocate it
2311 /* we should allocate requested block */
2312 } else if (goal == EXT4_EXT_CACHE_EXTENT) {
2313 /* block is already allocated */
2315 - le32_to_cpu(newex.ee_block)
2316 + ext_pblock(&newex);
2317 /* number of remaining blocks in the extent */
2318 allocated = ext4_ext_get_actual_len(&newex) -
2319 (iblock - le32_to_cpu(newex.ee_block));
2326 /* find extent for this block */
2327 path = ext4_ext_find_extent(inode, iblock, NULL);
2329 err = PTR_ERR(path);
2334 depth = ext_depth(inode);
2337 * consistent leaf must not be empty;
2338 * this situation is possible, though, _during_ tree modification;
2339 * this is why assert can't be put in ext4_ext_find_extent()
2341 BUG_ON(path[depth].p_ext == NULL && depth != 0);
2342 eh = path[depth].p_hdr;
2344 ex = path[depth].p_ext;
2346 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
2347 ext4_fsblk_t ee_start = ext_pblock(ex);
2348 unsigned short ee_len;
2351 * Uninitialized extents are treated as holes, except that
2352 * we split out initialized portions during a write.
2354 ee_len = ext4_ext_get_actual_len(ex);
2355 /* if found extent covers block, simply return it */
2356 if (iblock >= ee_block && iblock < ee_block + ee_len) {
2357 newblock = iblock - ee_block + ee_start;
2358 /* number of remaining blocks in the extent */
2359 allocated = ee_len - (iblock - ee_block);
2360 ext_debug("%u fit into %lu:%d -> %llu\n", iblock,
2361 ee_block, ee_len, newblock);
2363 /* Do not put uninitialized extent in the cache */
2364 if (!ext4_ext_is_uninitialized(ex)) {
2365 ext4_ext_put_in_cache(inode, ee_block,
2367 EXT4_EXT_CACHE_EXTENT);
2370 if (create == EXT4_CREATE_UNINITIALIZED_EXT)
2375 ret = ext4_ext_convert_to_initialized(handle, inode,
2388 * requested block isn't allocated yet;
2389 * we couldn't try to create block if create flag is zero
2393 * put just found gap into cache to speed up
2394 * subsequent requests
2396 ext4_ext_put_gap_in_cache(inode, path, iblock);
2400 * Okay, we need to do block allocation. Lazily initialize the block
2401 * allocation info here if necessary.
2403 if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
2404 ext4_init_block_alloc_info(inode);
2406 /* find neighbour allocated blocks */
2408 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
2412 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
2417 * See if request is beyond maximum number of blocks we can have in
2418 * a single extent. For an initialized extent this limit is
2419 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
2420 * EXT_UNINIT_MAX_LEN.
2422 if (max_blocks > EXT_INIT_MAX_LEN &&
2423 create != EXT4_CREATE_UNINITIALIZED_EXT)
2424 max_blocks = EXT_INIT_MAX_LEN;
2425 else if (max_blocks > EXT_UNINIT_MAX_LEN &&
2426 create == EXT4_CREATE_UNINITIALIZED_EXT)
2427 max_blocks = EXT_UNINIT_MAX_LEN;
2429 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
2430 newex.ee_block = cpu_to_le32(iblock);
2431 newex.ee_len = cpu_to_le16(max_blocks);
2432 err = ext4_ext_check_overlap(inode, &newex, path);
2434 allocated = ext4_ext_get_actual_len(&newex);
2436 allocated = max_blocks;
2438 /* allocate new block */
2440 ar.goal = ext4_ext_find_goal(inode, path, iblock);
2441 ar.logical = iblock;
2443 if (S_ISREG(inode->i_mode))
2444 ar.flags = EXT4_MB_HINT_DATA;
2446 /* disable in-core preallocation for non-regular files */
2448 newblock = ext4_mb_new_blocks(handle, &ar, &err);
2451 ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
2452 goal, newblock, allocated);
2454 /* try to insert new extent into found leaf and return */
2455 ext4_ext_store_pblock(&newex, newblock);
2456 newex.ee_len = cpu_to_le16(ar.len);
2457 if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */
2458 ext4_ext_mark_uninitialized(&newex);
2459 err = ext4_ext_insert_extent(handle, inode, path, &newex);
2461 /* free data blocks we just allocated */
2462 /* not a good idea to call discard here directly,
2463 * but otherwise we'd need to call it every free() */
2464 ext4_mb_discard_inode_preallocations(inode);
2465 ext4_free_blocks(handle, inode, ext_pblock(&newex),
2466 ext4_ext_get_actual_len(&newex), 0);
2470 if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
2471 EXT4_I(inode)->i_disksize = inode->i_size;
2473 /* previous routine could use block we allocated */
2474 newblock = ext_pblock(&newex);
2475 allocated = ext4_ext_get_actual_len(&newex);
2477 __set_bit(BH_New, &bh_result->b_state);
2479 /* Cache only when it is _not_ an uninitialized extent */
2480 if (create != EXT4_CREATE_UNINITIALIZED_EXT)
2481 ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
2482 EXT4_EXT_CACHE_EXTENT);
2484 if (allocated > max_blocks)
2485 allocated = max_blocks;
2486 ext4_ext_show_leaf(inode, path);
2487 __set_bit(BH_Mapped, &bh_result->b_state);
2488 bh_result->b_bdev = inode->i_sb->s_bdev;
2489 bh_result->b_blocknr = newblock;
2492 ext4_ext_drop_refs(path);
2495 return err ? err : allocated;
2498 void ext4_ext_truncate(struct inode * inode, struct page *page)
2500 struct address_space *mapping = inode->i_mapping;
2501 struct super_block *sb = inode->i_sb;
2502 ext4_lblk_t last_block;
2507 * probably first extent we're gonna free will be last in block
2509 err = ext4_writepage_trans_blocks(inode) + 3;
2510 handle = ext4_journal_start(inode, err);
2511 if (IS_ERR(handle)) {
2513 clear_highpage(page);
2514 flush_dcache_page(page);
2516 page_cache_release(page);
2522 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2524 down_write(&EXT4_I(inode)->i_data_sem);
2525 ext4_ext_invalidate_cache(inode);
2527 ext4_mb_discard_inode_preallocations(inode);
2530 * TODO: optimization is possible here.
2531 * Probably we need not scan at all,
2532 * because page truncation is enough.
2534 if (ext4_orphan_add(handle, inode))
2537 /* we have to know where to truncate from in crash case */
2538 EXT4_I(inode)->i_disksize = inode->i_size;
2539 ext4_mark_inode_dirty(handle, inode);
2541 last_block = (inode->i_size + sb->s_blocksize - 1)
2542 >> EXT4_BLOCK_SIZE_BITS(sb);
2543 err = ext4_ext_remove_space(inode, last_block);
2545 /* In a multi-transaction truncate, we only make the final
2546 * transaction synchronous.
2553 * If this was a simple ftruncate() and the file will remain alive,
2554 * then we need to clear up the orphan record which we created above.
2555 * However, if this was a real unlink then we were called by
2556 * ext4_delete_inode(), and we allow that function to clean up the
2557 * orphan info for us.
2560 ext4_orphan_del(handle, inode);
2562 up_write(&EXT4_I(inode)->i_data_sem);
2563 ext4_journal_stop(handle);
2567 * ext4_ext_writepage_trans_blocks:
2568 * calculate max number of blocks we could modify
2569 * in order to allocate new block for an inode
2571 int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
2575 needed = ext4_ext_calc_credits_for_insert(inode, NULL);
2577 /* caller wants to allocate num blocks, but note it includes sb */
2578 needed = needed * num - (num - 1);
2581 needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
2588 * preallocate space for a file. This implements ext4's fallocate inode
2589 * operation, which gets called from sys_fallocate system call.
2590 * For block-mapped files, posix_fallocate should fall back to the method
2591 * of writing zeroes to the required new blocks (the same behavior which is
2592 * expected for file systems which do not support fallocate() system call).
2594 long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
2598 unsigned long max_blocks;
2599 ext4_fsblk_t nblocks = 0;
2603 struct buffer_head map_bh;
2604 unsigned int credits, blkbits = inode->i_blkbits;
2607 * currently supporting (pre)allocate mode for extent-based
2610 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
2613 /* preallocation to directories is currently not supported */
2614 if (S_ISDIR(inode->i_mode))
2617 block = offset >> blkbits;
2618 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
2622 * credits to insert 1 extent into extent tree + buffers to be able to
2623 * modify 1 super block, 1 block bitmap and 1 group descriptor.
2625 credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
2626 down_write((&EXT4_I(inode)->i_data_sem));
2628 while (ret >= 0 && ret < max_blocks) {
2629 block = block + ret;
2630 max_blocks = max_blocks - ret;
2631 handle = ext4_journal_start(inode, credits);
2632 if (IS_ERR(handle)) {
2633 ret = PTR_ERR(handle);
2637 ret = ext4_ext_get_blocks(handle, inode, block,
2638 max_blocks, &map_bh,
2639 EXT4_CREATE_UNINITIALIZED_EXT, 0);
2642 ext4_error(inode->i_sb, "ext4_fallocate",
2643 "ext4_ext_get_blocks returned error: "
2644 "inode#%lu, block=%u, max_blocks=%lu",
2645 inode->i_ino, block, max_blocks);
2647 ext4_mark_inode_dirty(handle, inode);
2648 ret2 = ext4_journal_stop(handle);
2652 /* check wrap through sign-bit/zero here */
2653 if ((block + ret) < 0 || (block + ret) < block) {
2655 ext4_mark_inode_dirty(handle, inode);
2656 ret2 = ext4_journal_stop(handle);
2659 if (buffer_new(&map_bh) && ((block + ret) >
2660 (EXT4_BLOCK_ALIGN(i_size_read(inode), blkbits)
2662 nblocks = nblocks + ret;
2665 /* Update ctime if new blocks get allocated */
2667 struct timespec now;
2669 now = current_fs_time(inode->i_sb);
2670 if (!timespec_equal(&inode->i_ctime, &now))
2671 inode->i_ctime = now;
2674 ext4_mark_inode_dirty(handle, inode);
2675 ret2 = ext4_journal_stop(handle);
2680 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2683 up_write((&EXT4_I(inode)->i_data_sem));
2685 * Time to update the file size.
2686 * Update only when preallocation was requested beyond the file size.
2688 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
2689 (offset + len) > i_size_read(inode)) {
2692 * if no error, we assume preallocation succeeded
2695 mutex_lock(&inode->i_mutex);
2696 i_size_write(inode, offset + len);
2697 EXT4_I(inode)->i_disksize = i_size_read(inode);
2698 mutex_unlock(&inode->i_mutex);
2699 } else if (ret < 0 && nblocks) {
2700 /* Handle partial allocation scenario */
2703 mutex_lock(&inode->i_mutex);
2704 newsize = (nblocks << blkbits) + i_size_read(inode);
2705 i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits));
2706 EXT4_I(inode)->i_disksize = i_size_read(inode);
2707 mutex_unlock(&inode->i_mutex);
2711 return ret > 0 ? ret2 : ret;