Loading...
1/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * Architecture independence:
6 * Copyright (c) 2005, Bull S.A.
7 * Written by Pierre Peiffer <pierre.peiffer@bull.net>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public Licens
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
21 */
22
23/*
24 * Extents support for EXT4
25 *
26 * TODO:
27 * - ext4*_error() should be used in some situations
28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
29 * - smart tree reduction
30 */
31
32#include <linux/module.h>
33#include <linux/fs.h>
34#include <linux/time.h>
35#include <linux/jbd2.h>
36#include <linux/highuid.h>
37#include <linux/pagemap.h>
38#include <linux/quotaops.h>
39#include <linux/string.h>
40#include <linux/slab.h>
41#include <linux/falloc.h>
42#include <asm/uaccess.h>
43#include <linux/fiemap.h>
44#include "ext4_jbd2.h"
45#include "ext4_extents.h"
46
47#include <trace/events/ext4.h>
48
49static int ext4_split_extent(handle_t *handle,
50 struct inode *inode,
51 struct ext4_ext_path *path,
52 struct ext4_map_blocks *map,
53 int split_flag,
54 int flags);
55
56static int ext4_ext_truncate_extend_restart(handle_t *handle,
57 struct inode *inode,
58 int needed)
59{
60 int err;
61
62 if (!ext4_handle_valid(handle))
63 return 0;
64 if (handle->h_buffer_credits > needed)
65 return 0;
66 err = ext4_journal_extend(handle, needed);
67 if (err <= 0)
68 return err;
69 err = ext4_truncate_restart_trans(handle, inode, needed);
70 if (err == 0)
71 err = -EAGAIN;
72
73 return err;
74}
75
76/*
77 * could return:
78 * - EROFS
79 * - ENOMEM
80 */
81static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
82 struct ext4_ext_path *path)
83{
84 if (path->p_bh) {
85 /* path points to block */
86 return ext4_journal_get_write_access(handle, path->p_bh);
87 }
88 /* path points to leaf/index in inode body */
89 /* we use in-core data, no need to protect them */
90 return 0;
91}
92
93/*
94 * could return:
95 * - EROFS
96 * - ENOMEM
97 * - EIO
98 */
99static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
100 struct ext4_ext_path *path)
101{
102 int err;
103 if (path->p_bh) {
104 /* path points to block */
105 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
106 } else {
107 /* path points to leaf/index in inode body */
108 err = ext4_mark_inode_dirty(handle, inode);
109 }
110 return err;
111}
112
113static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
114 struct ext4_ext_path *path,
115 ext4_lblk_t block)
116{
117 int depth;
118
119 if (path) {
120 struct ext4_extent *ex;
121 depth = path->p_depth;
122
123 /*
124 * Try to predict block placement assuming that we are
125 * filling in a file which will eventually be
126 * non-sparse --- i.e., in the case of libbfd writing
127 * an ELF object sections out-of-order but in a way
128 * the eventually results in a contiguous object or
129 * executable file, or some database extending a table
130 * space file. However, this is actually somewhat
131 * non-ideal if we are writing a sparse file such as
132 * qemu or KVM writing a raw image file that is going
133 * to stay fairly sparse, since it will end up
134 * fragmenting the file system's free space. Maybe we
135 * should have some hueristics or some way to allow
136 * userspace to pass a hint to file system,
137 * especially if the latter case turns out to be
138 * common.
139 */
140 ex = path[depth].p_ext;
141 if (ex) {
142 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
143 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
144
145 if (block > ext_block)
146 return ext_pblk + (block - ext_block);
147 else
148 return ext_pblk - (ext_block - block);
149 }
150
151 /* it looks like index is empty;
152 * try to find starting block from index itself */
153 if (path[depth].p_bh)
154 return path[depth].p_bh->b_blocknr;
155 }
156
157 /* OK. use inode's group */
158 return ext4_inode_to_goal_block(inode);
159}
160
161/*
162 * Allocation for a meta data block
163 */
164static ext4_fsblk_t
165ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
166 struct ext4_ext_path *path,
167 struct ext4_extent *ex, int *err, unsigned int flags)
168{
169 ext4_fsblk_t goal, newblock;
170
171 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
172 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
173 NULL, err);
174 return newblock;
175}
176
177static inline int ext4_ext_space_block(struct inode *inode, int check)
178{
179 int size;
180
181 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
182 / sizeof(struct ext4_extent);
183 if (!check) {
184#ifdef AGGRESSIVE_TEST
185 if (size > 6)
186 size = 6;
187#endif
188 }
189 return size;
190}
191
192static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
193{
194 int size;
195
196 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
197 / sizeof(struct ext4_extent_idx);
198 if (!check) {
199#ifdef AGGRESSIVE_TEST
200 if (size > 5)
201 size = 5;
202#endif
203 }
204 return size;
205}
206
207static inline int ext4_ext_space_root(struct inode *inode, int check)
208{
209 int size;
210
211 size = sizeof(EXT4_I(inode)->i_data);
212 size -= sizeof(struct ext4_extent_header);
213 size /= sizeof(struct ext4_extent);
214 if (!check) {
215#ifdef AGGRESSIVE_TEST
216 if (size > 3)
217 size = 3;
218#endif
219 }
220 return size;
221}
222
223static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
224{
225 int size;
226
227 size = sizeof(EXT4_I(inode)->i_data);
228 size -= sizeof(struct ext4_extent_header);
229 size /= sizeof(struct ext4_extent_idx);
230 if (!check) {
231#ifdef AGGRESSIVE_TEST
232 if (size > 4)
233 size = 4;
234#endif
235 }
236 return size;
237}
238
239/*
240 * Calculate the number of metadata blocks needed
241 * to allocate @blocks
242 * Worse case is one block per extent
243 */
244int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
245{
246 struct ext4_inode_info *ei = EXT4_I(inode);
247 int idxs, num = 0;
248
249 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
250 / sizeof(struct ext4_extent_idx));
251
252 /*
253 * If the new delayed allocation block is contiguous with the
254 * previous da block, it can share index blocks with the
255 * previous block, so we only need to allocate a new index
256 * block every idxs leaf blocks. At ldxs**2 blocks, we need
257 * an additional index block, and at ldxs**3 blocks, yet
258 * another index blocks.
259 */
260 if (ei->i_da_metadata_calc_len &&
261 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
262 if ((ei->i_da_metadata_calc_len % idxs) == 0)
263 num++;
264 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
265 num++;
266 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
267 num++;
268 ei->i_da_metadata_calc_len = 0;
269 } else
270 ei->i_da_metadata_calc_len++;
271 ei->i_da_metadata_calc_last_lblock++;
272 return num;
273 }
274
275 /*
276 * In the worst case we need a new set of index blocks at
277 * every level of the inode's extent tree.
278 */
279 ei->i_da_metadata_calc_len = 1;
280 ei->i_da_metadata_calc_last_lblock = lblock;
281 return ext_depth(inode) + 1;
282}
283
284static int
285ext4_ext_max_entries(struct inode *inode, int depth)
286{
287 int max;
288
289 if (depth == ext_depth(inode)) {
290 if (depth == 0)
291 max = ext4_ext_space_root(inode, 1);
292 else
293 max = ext4_ext_space_root_idx(inode, 1);
294 } else {
295 if (depth == 0)
296 max = ext4_ext_space_block(inode, 1);
297 else
298 max = ext4_ext_space_block_idx(inode, 1);
299 }
300
301 return max;
302}
303
304static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
305{
306 ext4_fsblk_t block = ext4_ext_pblock(ext);
307 int len = ext4_ext_get_actual_len(ext);
308
309 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
310}
311
312static int ext4_valid_extent_idx(struct inode *inode,
313 struct ext4_extent_idx *ext_idx)
314{
315 ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
316
317 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
318}
319
320static int ext4_valid_extent_entries(struct inode *inode,
321 struct ext4_extent_header *eh,
322 int depth)
323{
324 struct ext4_extent *ext;
325 struct ext4_extent_idx *ext_idx;
326 unsigned short entries;
327 if (eh->eh_entries == 0)
328 return 1;
329
330 entries = le16_to_cpu(eh->eh_entries);
331
332 if (depth == 0) {
333 /* leaf entries */
334 ext = EXT_FIRST_EXTENT(eh);
335 while (entries) {
336 if (!ext4_valid_extent(inode, ext))
337 return 0;
338 ext++;
339 entries--;
340 }
341 } else {
342 ext_idx = EXT_FIRST_INDEX(eh);
343 while (entries) {
344 if (!ext4_valid_extent_idx(inode, ext_idx))
345 return 0;
346 ext_idx++;
347 entries--;
348 }
349 }
350 return 1;
351}
352
353static int __ext4_ext_check(const char *function, unsigned int line,
354 struct inode *inode, struct ext4_extent_header *eh,
355 int depth)
356{
357 const char *error_msg;
358 int max = 0;
359
360 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
361 error_msg = "invalid magic";
362 goto corrupted;
363 }
364 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
365 error_msg = "unexpected eh_depth";
366 goto corrupted;
367 }
368 if (unlikely(eh->eh_max == 0)) {
369 error_msg = "invalid eh_max";
370 goto corrupted;
371 }
372 max = ext4_ext_max_entries(inode, depth);
373 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
374 error_msg = "too large eh_max";
375 goto corrupted;
376 }
377 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
378 error_msg = "invalid eh_entries";
379 goto corrupted;
380 }
381 if (!ext4_valid_extent_entries(inode, eh, depth)) {
382 error_msg = "invalid extent entries";
383 goto corrupted;
384 }
385 return 0;
386
387corrupted:
388 ext4_error_inode(inode, function, line, 0,
389 "bad header/extent: %s - magic %x, "
390 "entries %u, max %u(%u), depth %u(%u)",
391 error_msg, le16_to_cpu(eh->eh_magic),
392 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
393 max, le16_to_cpu(eh->eh_depth), depth);
394
395 return -EIO;
396}
397
398#define ext4_ext_check(inode, eh, depth) \
399 __ext4_ext_check(__func__, __LINE__, inode, eh, depth)
400
401int ext4_ext_check_inode(struct inode *inode)
402{
403 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
404}
405
406#ifdef EXT_DEBUG
407static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
408{
409 int k, l = path->p_depth;
410
411 ext_debug("path:");
412 for (k = 0; k <= l; k++, path++) {
413 if (path->p_idx) {
414 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
415 ext4_idx_pblock(path->p_idx));
416 } else if (path->p_ext) {
417 ext_debug(" %d:[%d]%d:%llu ",
418 le32_to_cpu(path->p_ext->ee_block),
419 ext4_ext_is_uninitialized(path->p_ext),
420 ext4_ext_get_actual_len(path->p_ext),
421 ext4_ext_pblock(path->p_ext));
422 } else
423 ext_debug(" []");
424 }
425 ext_debug("\n");
426}
427
428static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
429{
430 int depth = ext_depth(inode);
431 struct ext4_extent_header *eh;
432 struct ext4_extent *ex;
433 int i;
434
435 if (!path)
436 return;
437
438 eh = path[depth].p_hdr;
439 ex = EXT_FIRST_EXTENT(eh);
440
441 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
442
443 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
444 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
445 ext4_ext_is_uninitialized(ex),
446 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
447 }
448 ext_debug("\n");
449}
450
451static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
452 ext4_fsblk_t newblock, int level)
453{
454 int depth = ext_depth(inode);
455 struct ext4_extent *ex;
456
457 if (depth != level) {
458 struct ext4_extent_idx *idx;
459 idx = path[level].p_idx;
460 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
461 ext_debug("%d: move %d:%llu in new index %llu\n", level,
462 le32_to_cpu(idx->ei_block),
463 ext4_idx_pblock(idx),
464 newblock);
465 idx++;
466 }
467
468 return;
469 }
470
471 ex = path[depth].p_ext;
472 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
473 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
474 le32_to_cpu(ex->ee_block),
475 ext4_ext_pblock(ex),
476 ext4_ext_is_uninitialized(ex),
477 ext4_ext_get_actual_len(ex),
478 newblock);
479 ex++;
480 }
481}
482
483#else
484#define ext4_ext_show_path(inode, path)
485#define ext4_ext_show_leaf(inode, path)
486#define ext4_ext_show_move(inode, path, newblock, level)
487#endif
488
489void ext4_ext_drop_refs(struct ext4_ext_path *path)
490{
491 int depth = path->p_depth;
492 int i;
493
494 for (i = 0; i <= depth; i++, path++)
495 if (path->p_bh) {
496 brelse(path->p_bh);
497 path->p_bh = NULL;
498 }
499}
500
501/*
502 * ext4_ext_binsearch_idx:
503 * binary search for the closest index of the given block
504 * the header must be checked before calling this
505 */
506static void
507ext4_ext_binsearch_idx(struct inode *inode,
508 struct ext4_ext_path *path, ext4_lblk_t block)
509{
510 struct ext4_extent_header *eh = path->p_hdr;
511 struct ext4_extent_idx *r, *l, *m;
512
513
514 ext_debug("binsearch for %u(idx): ", block);
515
516 l = EXT_FIRST_INDEX(eh) + 1;
517 r = EXT_LAST_INDEX(eh);
518 while (l <= r) {
519 m = l + (r - l) / 2;
520 if (block < le32_to_cpu(m->ei_block))
521 r = m - 1;
522 else
523 l = m + 1;
524 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
525 m, le32_to_cpu(m->ei_block),
526 r, le32_to_cpu(r->ei_block));
527 }
528
529 path->p_idx = l - 1;
530 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
531 ext4_idx_pblock(path->p_idx));
532
533#ifdef CHECK_BINSEARCH
534 {
535 struct ext4_extent_idx *chix, *ix;
536 int k;
537
538 chix = ix = EXT_FIRST_INDEX(eh);
539 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
540 if (k != 0 &&
541 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
542 printk(KERN_DEBUG "k=%d, ix=0x%p, "
543 "first=0x%p\n", k,
544 ix, EXT_FIRST_INDEX(eh));
545 printk(KERN_DEBUG "%u <= %u\n",
546 le32_to_cpu(ix->ei_block),
547 le32_to_cpu(ix[-1].ei_block));
548 }
549 BUG_ON(k && le32_to_cpu(ix->ei_block)
550 <= le32_to_cpu(ix[-1].ei_block));
551 if (block < le32_to_cpu(ix->ei_block))
552 break;
553 chix = ix;
554 }
555 BUG_ON(chix != path->p_idx);
556 }
557#endif
558
559}
560
561/*
562 * ext4_ext_binsearch:
563 * binary search for closest extent of the given block
564 * the header must be checked before calling this
565 */
566static void
567ext4_ext_binsearch(struct inode *inode,
568 struct ext4_ext_path *path, ext4_lblk_t block)
569{
570 struct ext4_extent_header *eh = path->p_hdr;
571 struct ext4_extent *r, *l, *m;
572
573 if (eh->eh_entries == 0) {
574 /*
575 * this leaf is empty:
576 * we get such a leaf in split/add case
577 */
578 return;
579 }
580
581 ext_debug("binsearch for %u: ", block);
582
583 l = EXT_FIRST_EXTENT(eh) + 1;
584 r = EXT_LAST_EXTENT(eh);
585
586 while (l <= r) {
587 m = l + (r - l) / 2;
588 if (block < le32_to_cpu(m->ee_block))
589 r = m - 1;
590 else
591 l = m + 1;
592 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
593 m, le32_to_cpu(m->ee_block),
594 r, le32_to_cpu(r->ee_block));
595 }
596
597 path->p_ext = l - 1;
598 ext_debug(" -> %d:%llu:[%d]%d ",
599 le32_to_cpu(path->p_ext->ee_block),
600 ext4_ext_pblock(path->p_ext),
601 ext4_ext_is_uninitialized(path->p_ext),
602 ext4_ext_get_actual_len(path->p_ext));
603
604#ifdef CHECK_BINSEARCH
605 {
606 struct ext4_extent *chex, *ex;
607 int k;
608
609 chex = ex = EXT_FIRST_EXTENT(eh);
610 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
611 BUG_ON(k && le32_to_cpu(ex->ee_block)
612 <= le32_to_cpu(ex[-1].ee_block));
613 if (block < le32_to_cpu(ex->ee_block))
614 break;
615 chex = ex;
616 }
617 BUG_ON(chex != path->p_ext);
618 }
619#endif
620
621}
622
623int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
624{
625 struct ext4_extent_header *eh;
626
627 eh = ext_inode_hdr(inode);
628 eh->eh_depth = 0;
629 eh->eh_entries = 0;
630 eh->eh_magic = EXT4_EXT_MAGIC;
631 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
632 ext4_mark_inode_dirty(handle, inode);
633 ext4_ext_invalidate_cache(inode);
634 return 0;
635}
636
637struct ext4_ext_path *
638ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
639 struct ext4_ext_path *path)
640{
641 struct ext4_extent_header *eh;
642 struct buffer_head *bh;
643 short int depth, i, ppos = 0, alloc = 0;
644
645 eh = ext_inode_hdr(inode);
646 depth = ext_depth(inode);
647
648 /* account possible depth increase */
649 if (!path) {
650 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
651 GFP_NOFS);
652 if (!path)
653 return ERR_PTR(-ENOMEM);
654 alloc = 1;
655 }
656 path[0].p_hdr = eh;
657 path[0].p_bh = NULL;
658
659 i = depth;
660 /* walk through the tree */
661 while (i) {
662 int need_to_validate = 0;
663
664 ext_debug("depth %d: num %d, max %d\n",
665 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
666
667 ext4_ext_binsearch_idx(inode, path + ppos, block);
668 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
669 path[ppos].p_depth = i;
670 path[ppos].p_ext = NULL;
671
672 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
673 if (unlikely(!bh))
674 goto err;
675 if (!bh_uptodate_or_lock(bh)) {
676 trace_ext4_ext_load_extent(inode, block,
677 path[ppos].p_block);
678 if (bh_submit_read(bh) < 0) {
679 put_bh(bh);
680 goto err;
681 }
682 /* validate the extent entries */
683 need_to_validate = 1;
684 }
685 eh = ext_block_hdr(bh);
686 ppos++;
687 if (unlikely(ppos > depth)) {
688 put_bh(bh);
689 EXT4_ERROR_INODE(inode,
690 "ppos %d > depth %d", ppos, depth);
691 goto err;
692 }
693 path[ppos].p_bh = bh;
694 path[ppos].p_hdr = eh;
695 i--;
696
697 if (need_to_validate && ext4_ext_check(inode, eh, i))
698 goto err;
699 }
700
701 path[ppos].p_depth = i;
702 path[ppos].p_ext = NULL;
703 path[ppos].p_idx = NULL;
704
705 /* find extent */
706 ext4_ext_binsearch(inode, path + ppos, block);
707 /* if not an empty leaf */
708 if (path[ppos].p_ext)
709 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
710
711 ext4_ext_show_path(inode, path);
712
713 return path;
714
715err:
716 ext4_ext_drop_refs(path);
717 if (alloc)
718 kfree(path);
719 return ERR_PTR(-EIO);
720}
721
722/*
723 * ext4_ext_insert_index:
724 * insert new index [@logical;@ptr] into the block at @curp;
725 * check where to insert: before @curp or after @curp
726 */
727static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
728 struct ext4_ext_path *curp,
729 int logical, ext4_fsblk_t ptr)
730{
731 struct ext4_extent_idx *ix;
732 int len, err;
733
734 err = ext4_ext_get_access(handle, inode, curp);
735 if (err)
736 return err;
737
738 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
739 EXT4_ERROR_INODE(inode,
740 "logical %d == ei_block %d!",
741 logical, le32_to_cpu(curp->p_idx->ei_block));
742 return -EIO;
743 }
744
745 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
746 >= le16_to_cpu(curp->p_hdr->eh_max))) {
747 EXT4_ERROR_INODE(inode,
748 "eh_entries %d >= eh_max %d!",
749 le16_to_cpu(curp->p_hdr->eh_entries),
750 le16_to_cpu(curp->p_hdr->eh_max));
751 return -EIO;
752 }
753
754 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
755 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
756 /* insert after */
757 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
758 len = (len - 1) * sizeof(struct ext4_extent_idx);
759 len = len < 0 ? 0 : len;
760 ext_debug("insert new index %d after: %llu. "
761 "move %d from 0x%p to 0x%p\n",
762 logical, ptr, len,
763 (curp->p_idx + 1), (curp->p_idx + 2));
764 memmove(curp->p_idx + 2, curp->p_idx + 1, len);
765 }
766 ix = curp->p_idx + 1;
767 } else {
768 /* insert before */
769 len = len * sizeof(struct ext4_extent_idx);
770 len = len < 0 ? 0 : len;
771 ext_debug("insert new index %d before: %llu. "
772 "move %d from 0x%p to 0x%p\n",
773 logical, ptr, len,
774 curp->p_idx, (curp->p_idx + 1));
775 memmove(curp->p_idx + 1, curp->p_idx, len);
776 ix = curp->p_idx;
777 }
778
779 ix->ei_block = cpu_to_le32(logical);
780 ext4_idx_store_pblock(ix, ptr);
781 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
782
783 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
784 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
785 return -EIO;
786 }
787
788 err = ext4_ext_dirty(handle, inode, curp);
789 ext4_std_error(inode->i_sb, err);
790
791 return err;
792}
793
794/*
795 * ext4_ext_split:
796 * inserts new subtree into the path, using free index entry
797 * at depth @at:
798 * - allocates all needed blocks (new leaf and all intermediate index blocks)
799 * - makes decision where to split
800 * - moves remaining extents and index entries (right to the split point)
801 * into the newly allocated blocks
802 * - initializes subtree
803 */
804static int ext4_ext_split(handle_t *handle, struct inode *inode,
805 unsigned int flags,
806 struct ext4_ext_path *path,
807 struct ext4_extent *newext, int at)
808{
809 struct buffer_head *bh = NULL;
810 int depth = ext_depth(inode);
811 struct ext4_extent_header *neh;
812 struct ext4_extent_idx *fidx;
813 int i = at, k, m, a;
814 ext4_fsblk_t newblock, oldblock;
815 __le32 border;
816 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
817 int err = 0;
818
819 /* make decision: where to split? */
820 /* FIXME: now decision is simplest: at current extent */
821
822 /* if current leaf will be split, then we should use
823 * border from split point */
824 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
825 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
826 return -EIO;
827 }
828 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
829 border = path[depth].p_ext[1].ee_block;
830 ext_debug("leaf will be split."
831 " next leaf starts at %d\n",
832 le32_to_cpu(border));
833 } else {
834 border = newext->ee_block;
835 ext_debug("leaf will be added."
836 " next leaf starts at %d\n",
837 le32_to_cpu(border));
838 }
839
840 /*
841 * If error occurs, then we break processing
842 * and mark filesystem read-only. index won't
843 * be inserted and tree will be in consistent
844 * state. Next mount will repair buffers too.
845 */
846
847 /*
848 * Get array to track all allocated blocks.
849 * We need this to handle errors and free blocks
850 * upon them.
851 */
852 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
853 if (!ablocks)
854 return -ENOMEM;
855
856 /* allocate all needed blocks */
857 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
858 for (a = 0; a < depth - at; a++) {
859 newblock = ext4_ext_new_meta_block(handle, inode, path,
860 newext, &err, flags);
861 if (newblock == 0)
862 goto cleanup;
863 ablocks[a] = newblock;
864 }
865
866 /* initialize new leaf */
867 newblock = ablocks[--a];
868 if (unlikely(newblock == 0)) {
869 EXT4_ERROR_INODE(inode, "newblock == 0!");
870 err = -EIO;
871 goto cleanup;
872 }
873 bh = sb_getblk(inode->i_sb, newblock);
874 if (!bh) {
875 err = -EIO;
876 goto cleanup;
877 }
878 lock_buffer(bh);
879
880 err = ext4_journal_get_create_access(handle, bh);
881 if (err)
882 goto cleanup;
883
884 neh = ext_block_hdr(bh);
885 neh->eh_entries = 0;
886 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
887 neh->eh_magic = EXT4_EXT_MAGIC;
888 neh->eh_depth = 0;
889
890 /* move remainder of path[depth] to the new leaf */
891 if (unlikely(path[depth].p_hdr->eh_entries !=
892 path[depth].p_hdr->eh_max)) {
893 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
894 path[depth].p_hdr->eh_entries,
895 path[depth].p_hdr->eh_max);
896 err = -EIO;
897 goto cleanup;
898 }
899 /* start copy from next extent */
900 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
901 ext4_ext_show_move(inode, path, newblock, depth);
902 if (m) {
903 struct ext4_extent *ex;
904 ex = EXT_FIRST_EXTENT(neh);
905 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
906 le16_add_cpu(&neh->eh_entries, m);
907 }
908
909 set_buffer_uptodate(bh);
910 unlock_buffer(bh);
911
912 err = ext4_handle_dirty_metadata(handle, inode, bh);
913 if (err)
914 goto cleanup;
915 brelse(bh);
916 bh = NULL;
917
918 /* correct old leaf */
919 if (m) {
920 err = ext4_ext_get_access(handle, inode, path + depth);
921 if (err)
922 goto cleanup;
923 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
924 err = ext4_ext_dirty(handle, inode, path + depth);
925 if (err)
926 goto cleanup;
927
928 }
929
930 /* create intermediate indexes */
931 k = depth - at - 1;
932 if (unlikely(k < 0)) {
933 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
934 err = -EIO;
935 goto cleanup;
936 }
937 if (k)
938 ext_debug("create %d intermediate indices\n", k);
939 /* insert new index into current index block */
940 /* current depth stored in i var */
941 i = depth - 1;
942 while (k--) {
943 oldblock = newblock;
944 newblock = ablocks[--a];
945 bh = sb_getblk(inode->i_sb, newblock);
946 if (!bh) {
947 err = -EIO;
948 goto cleanup;
949 }
950 lock_buffer(bh);
951
952 err = ext4_journal_get_create_access(handle, bh);
953 if (err)
954 goto cleanup;
955
956 neh = ext_block_hdr(bh);
957 neh->eh_entries = cpu_to_le16(1);
958 neh->eh_magic = EXT4_EXT_MAGIC;
959 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
960 neh->eh_depth = cpu_to_le16(depth - i);
961 fidx = EXT_FIRST_INDEX(neh);
962 fidx->ei_block = border;
963 ext4_idx_store_pblock(fidx, oldblock);
964
965 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
966 i, newblock, le32_to_cpu(border), oldblock);
967
968 /* move remainder of path[i] to the new index block */
969 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
970 EXT_LAST_INDEX(path[i].p_hdr))) {
971 EXT4_ERROR_INODE(inode,
972 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
973 le32_to_cpu(path[i].p_ext->ee_block));
974 err = -EIO;
975 goto cleanup;
976 }
977 /* start copy indexes */
978 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
979 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
980 EXT_MAX_INDEX(path[i].p_hdr));
981 ext4_ext_show_move(inode, path, newblock, i);
982 if (m) {
983 memmove(++fidx, path[i].p_idx,
984 sizeof(struct ext4_extent_idx) * m);
985 le16_add_cpu(&neh->eh_entries, m);
986 }
987 set_buffer_uptodate(bh);
988 unlock_buffer(bh);
989
990 err = ext4_handle_dirty_metadata(handle, inode, bh);
991 if (err)
992 goto cleanup;
993 brelse(bh);
994 bh = NULL;
995
996 /* correct old index */
997 if (m) {
998 err = ext4_ext_get_access(handle, inode, path + i);
999 if (err)
1000 goto cleanup;
1001 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1002 err = ext4_ext_dirty(handle, inode, path + i);
1003 if (err)
1004 goto cleanup;
1005 }
1006
1007 i--;
1008 }
1009
1010 /* insert new index */
1011 err = ext4_ext_insert_index(handle, inode, path + at,
1012 le32_to_cpu(border), newblock);
1013
1014cleanup:
1015 if (bh) {
1016 if (buffer_locked(bh))
1017 unlock_buffer(bh);
1018 brelse(bh);
1019 }
1020
1021 if (err) {
1022 /* free all allocated blocks in error case */
1023 for (i = 0; i < depth; i++) {
1024 if (!ablocks[i])
1025 continue;
1026 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1027 EXT4_FREE_BLOCKS_METADATA);
1028 }
1029 }
1030 kfree(ablocks);
1031
1032 return err;
1033}
1034
1035/*
1036 * ext4_ext_grow_indepth:
1037 * implements tree growing procedure:
1038 * - allocates new block
1039 * - moves top-level data (index block or leaf) into the new block
1040 * - initializes new top-level, creating index that points to the
1041 * just created block
1042 */
1043static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1044 unsigned int flags,
1045 struct ext4_ext_path *path,
1046 struct ext4_extent *newext)
1047{
1048 struct ext4_ext_path *curp = path;
1049 struct ext4_extent_header *neh;
1050 struct buffer_head *bh;
1051 ext4_fsblk_t newblock;
1052 int err = 0;
1053
1054 newblock = ext4_ext_new_meta_block(handle, inode, path,
1055 newext, &err, flags);
1056 if (newblock == 0)
1057 return err;
1058
1059 bh = sb_getblk(inode->i_sb, newblock);
1060 if (!bh) {
1061 err = -EIO;
1062 ext4_std_error(inode->i_sb, err);
1063 return err;
1064 }
1065 lock_buffer(bh);
1066
1067 err = ext4_journal_get_create_access(handle, bh);
1068 if (err) {
1069 unlock_buffer(bh);
1070 goto out;
1071 }
1072
1073 /* move top-level index/leaf into new block */
1074 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
1075
1076 /* set size of new block */
1077 neh = ext_block_hdr(bh);
1078 /* old root could have indexes or leaves
1079 * so calculate e_max right way */
1080 if (ext_depth(inode))
1081 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1082 else
1083 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1084 neh->eh_magic = EXT4_EXT_MAGIC;
1085 set_buffer_uptodate(bh);
1086 unlock_buffer(bh);
1087
1088 err = ext4_handle_dirty_metadata(handle, inode, bh);
1089 if (err)
1090 goto out;
1091
1092 /* create index in new top-level index: num,max,pointer */
1093 err = ext4_ext_get_access(handle, inode, curp);
1094 if (err)
1095 goto out;
1096
1097 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
1098 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1099 curp->p_hdr->eh_entries = cpu_to_le16(1);
1100 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
1101
1102 if (path[0].p_hdr->eh_depth)
1103 curp->p_idx->ei_block =
1104 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
1105 else
1106 curp->p_idx->ei_block =
1107 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
1108 ext4_idx_store_pblock(curp->p_idx, newblock);
1109
1110 neh = ext_inode_hdr(inode);
1111 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1112 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1113 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1114 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1115
1116 neh->eh_depth = cpu_to_le16(path->p_depth + 1);
1117 err = ext4_ext_dirty(handle, inode, curp);
1118out:
1119 brelse(bh);
1120
1121 return err;
1122}
1123
1124/*
1125 * ext4_ext_create_new_leaf:
1126 * finds empty index and adds new leaf.
1127 * if no free index is found, then it requests in-depth growing.
1128 */
1129static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1130 unsigned int flags,
1131 struct ext4_ext_path *path,
1132 struct ext4_extent *newext)
1133{
1134 struct ext4_ext_path *curp;
1135 int depth, i, err = 0;
1136
1137repeat:
1138 i = depth = ext_depth(inode);
1139
1140 /* walk up to the tree and look for free index entry */
1141 curp = path + depth;
1142 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1143 i--;
1144 curp--;
1145 }
1146
1147 /* we use already allocated block for index block,
1148 * so subsequent data blocks should be contiguous */
1149 if (EXT_HAS_FREE_INDEX(curp)) {
1150 /* if we found index with free entry, then use that
1151 * entry: create all needed subtree and add new leaf */
1152 err = ext4_ext_split(handle, inode, flags, path, newext, i);
1153 if (err)
1154 goto out;
1155
1156 /* refill path */
1157 ext4_ext_drop_refs(path);
1158 path = ext4_ext_find_extent(inode,
1159 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1160 path);
1161 if (IS_ERR(path))
1162 err = PTR_ERR(path);
1163 } else {
1164 /* tree is full, time to grow in depth */
1165 err = ext4_ext_grow_indepth(handle, inode, flags,
1166 path, newext);
1167 if (err)
1168 goto out;
1169
1170 /* refill path */
1171 ext4_ext_drop_refs(path);
1172 path = ext4_ext_find_extent(inode,
1173 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1174 path);
1175 if (IS_ERR(path)) {
1176 err = PTR_ERR(path);
1177 goto out;
1178 }
1179
1180 /*
1181 * only first (depth 0 -> 1) produces free space;
1182 * in all other cases we have to split the grown tree
1183 */
1184 depth = ext_depth(inode);
1185 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1186 /* now we need to split */
1187 goto repeat;
1188 }
1189 }
1190
1191out:
1192 return err;
1193}
1194
1195/*
1196 * search the closest allocated block to the left for *logical
1197 * and returns it at @logical + it's physical address at @phys
1198 * if *logical is the smallest allocated block, the function
1199 * returns 0 at @phys
1200 * return value contains 0 (success) or error code
1201 */
1202static int ext4_ext_search_left(struct inode *inode,
1203 struct ext4_ext_path *path,
1204 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1205{
1206 struct ext4_extent_idx *ix;
1207 struct ext4_extent *ex;
1208 int depth, ee_len;
1209
1210 if (unlikely(path == NULL)) {
1211 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1212 return -EIO;
1213 }
1214 depth = path->p_depth;
1215 *phys = 0;
1216
1217 if (depth == 0 && path->p_ext == NULL)
1218 return 0;
1219
1220 /* usually extent in the path covers blocks smaller
1221 * then *logical, but it can be that extent is the
1222 * first one in the file */
1223
1224 ex = path[depth].p_ext;
1225 ee_len = ext4_ext_get_actual_len(ex);
1226 if (*logical < le32_to_cpu(ex->ee_block)) {
1227 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1228 EXT4_ERROR_INODE(inode,
1229 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1230 *logical, le32_to_cpu(ex->ee_block));
1231 return -EIO;
1232 }
1233 while (--depth >= 0) {
1234 ix = path[depth].p_idx;
1235 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1236 EXT4_ERROR_INODE(inode,
1237 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1238 ix != NULL ? ix->ei_block : 0,
1239 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1240 EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0,
1241 depth);
1242 return -EIO;
1243 }
1244 }
1245 return 0;
1246 }
1247
1248 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1249 EXT4_ERROR_INODE(inode,
1250 "logical %d < ee_block %d + ee_len %d!",
1251 *logical, le32_to_cpu(ex->ee_block), ee_len);
1252 return -EIO;
1253 }
1254
1255 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1256 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1257 return 0;
1258}
1259
1260/*
1261 * search the closest allocated block to the right for *logical
1262 * and returns it at @logical + it's physical address at @phys
1263 * if *logical is the smallest allocated block, the function
1264 * returns 0 at @phys
1265 * return value contains 0 (success) or error code
1266 */
1267static int ext4_ext_search_right(struct inode *inode,
1268 struct ext4_ext_path *path,
1269 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1270{
1271 struct buffer_head *bh = NULL;
1272 struct ext4_extent_header *eh;
1273 struct ext4_extent_idx *ix;
1274 struct ext4_extent *ex;
1275 ext4_fsblk_t block;
1276 int depth; /* Note, NOT eh_depth; depth from top of tree */
1277 int ee_len;
1278
1279 if (unlikely(path == NULL)) {
1280 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1281 return -EIO;
1282 }
1283 depth = path->p_depth;
1284 *phys = 0;
1285
1286 if (depth == 0 && path->p_ext == NULL)
1287 return 0;
1288
1289 /* usually extent in the path covers blocks smaller
1290 * then *logical, but it can be that extent is the
1291 * first one in the file */
1292
1293 ex = path[depth].p_ext;
1294 ee_len = ext4_ext_get_actual_len(ex);
1295 if (*logical < le32_to_cpu(ex->ee_block)) {
1296 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1297 EXT4_ERROR_INODE(inode,
1298 "first_extent(path[%d].p_hdr) != ex",
1299 depth);
1300 return -EIO;
1301 }
1302 while (--depth >= 0) {
1303 ix = path[depth].p_idx;
1304 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1305 EXT4_ERROR_INODE(inode,
1306 "ix != EXT_FIRST_INDEX *logical %d!",
1307 *logical);
1308 return -EIO;
1309 }
1310 }
1311 *logical = le32_to_cpu(ex->ee_block);
1312 *phys = ext4_ext_pblock(ex);
1313 return 0;
1314 }
1315
1316 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1317 EXT4_ERROR_INODE(inode,
1318 "logical %d < ee_block %d + ee_len %d!",
1319 *logical, le32_to_cpu(ex->ee_block), ee_len);
1320 return -EIO;
1321 }
1322
1323 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1324 /* next allocated block in this leaf */
1325 ex++;
1326 *logical = le32_to_cpu(ex->ee_block);
1327 *phys = ext4_ext_pblock(ex);
1328 return 0;
1329 }
1330
1331 /* go up and search for index to the right */
1332 while (--depth >= 0) {
1333 ix = path[depth].p_idx;
1334 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1335 goto got_index;
1336 }
1337
1338 /* we've gone up to the root and found no index to the right */
1339 return 0;
1340
1341got_index:
1342 /* we've found index to the right, let's
1343 * follow it and find the closest allocated
1344 * block to the right */
1345 ix++;
1346 block = ext4_idx_pblock(ix);
1347 while (++depth < path->p_depth) {
1348 bh = sb_bread(inode->i_sb, block);
1349 if (bh == NULL)
1350 return -EIO;
1351 eh = ext_block_hdr(bh);
1352 /* subtract from p_depth to get proper eh_depth */
1353 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1354 put_bh(bh);
1355 return -EIO;
1356 }
1357 ix = EXT_FIRST_INDEX(eh);
1358 block = ext4_idx_pblock(ix);
1359 put_bh(bh);
1360 }
1361
1362 bh = sb_bread(inode->i_sb, block);
1363 if (bh == NULL)
1364 return -EIO;
1365 eh = ext_block_hdr(bh);
1366 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1367 put_bh(bh);
1368 return -EIO;
1369 }
1370 ex = EXT_FIRST_EXTENT(eh);
1371 *logical = le32_to_cpu(ex->ee_block);
1372 *phys = ext4_ext_pblock(ex);
1373 put_bh(bh);
1374 return 0;
1375}
1376
1377/*
1378 * ext4_ext_next_allocated_block:
1379 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1380 * NOTE: it considers block number from index entry as
1381 * allocated block. Thus, index entries have to be consistent
1382 * with leaves.
1383 */
1384static ext4_lblk_t
1385ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1386{
1387 int depth;
1388
1389 BUG_ON(path == NULL);
1390 depth = path->p_depth;
1391
1392 if (depth == 0 && path->p_ext == NULL)
1393 return EXT_MAX_BLOCKS;
1394
1395 while (depth >= 0) {
1396 if (depth == path->p_depth) {
1397 /* leaf */
1398 if (path[depth].p_ext !=
1399 EXT_LAST_EXTENT(path[depth].p_hdr))
1400 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1401 } else {
1402 /* index */
1403 if (path[depth].p_idx !=
1404 EXT_LAST_INDEX(path[depth].p_hdr))
1405 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1406 }
1407 depth--;
1408 }
1409
1410 return EXT_MAX_BLOCKS;
1411}
1412
1413/*
1414 * ext4_ext_next_leaf_block:
1415 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1416 */
1417static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1418{
1419 int depth;
1420
1421 BUG_ON(path == NULL);
1422 depth = path->p_depth;
1423
1424 /* zero-tree has no leaf blocks at all */
1425 if (depth == 0)
1426 return EXT_MAX_BLOCKS;
1427
1428 /* go to index block */
1429 depth--;
1430
1431 while (depth >= 0) {
1432 if (path[depth].p_idx !=
1433 EXT_LAST_INDEX(path[depth].p_hdr))
1434 return (ext4_lblk_t)
1435 le32_to_cpu(path[depth].p_idx[1].ei_block);
1436 depth--;
1437 }
1438
1439 return EXT_MAX_BLOCKS;
1440}
1441
1442/*
1443 * ext4_ext_correct_indexes:
1444 * if leaf gets modified and modified extent is first in the leaf,
1445 * then we have to correct all indexes above.
1446 * TODO: do we need to correct tree in all cases?
1447 */
1448static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1449 struct ext4_ext_path *path)
1450{
1451 struct ext4_extent_header *eh;
1452 int depth = ext_depth(inode);
1453 struct ext4_extent *ex;
1454 __le32 border;
1455 int k, err = 0;
1456
1457 eh = path[depth].p_hdr;
1458 ex = path[depth].p_ext;
1459
1460 if (unlikely(ex == NULL || eh == NULL)) {
1461 EXT4_ERROR_INODE(inode,
1462 "ex %p == NULL or eh %p == NULL", ex, eh);
1463 return -EIO;
1464 }
1465
1466 if (depth == 0) {
1467 /* there is no tree at all */
1468 return 0;
1469 }
1470
1471 if (ex != EXT_FIRST_EXTENT(eh)) {
1472 /* we correct tree if first leaf got modified only */
1473 return 0;
1474 }
1475
1476 /*
1477 * TODO: we need correction if border is smaller than current one
1478 */
1479 k = depth - 1;
1480 border = path[depth].p_ext->ee_block;
1481 err = ext4_ext_get_access(handle, inode, path + k);
1482 if (err)
1483 return err;
1484 path[k].p_idx->ei_block = border;
1485 err = ext4_ext_dirty(handle, inode, path + k);
1486 if (err)
1487 return err;
1488
1489 while (k--) {
1490 /* change all left-side indexes */
1491 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1492 break;
1493 err = ext4_ext_get_access(handle, inode, path + k);
1494 if (err)
1495 break;
1496 path[k].p_idx->ei_block = border;
1497 err = ext4_ext_dirty(handle, inode, path + k);
1498 if (err)
1499 break;
1500 }
1501
1502 return err;
1503}
1504
1505int
1506ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1507 struct ext4_extent *ex2)
1508{
1509 unsigned short ext1_ee_len, ext2_ee_len, max_len;
1510
1511 /*
1512 * Make sure that either both extents are uninitialized, or
1513 * both are _not_.
1514 */
1515 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1516 return 0;
1517
1518 if (ext4_ext_is_uninitialized(ex1))
1519 max_len = EXT_UNINIT_MAX_LEN;
1520 else
1521 max_len = EXT_INIT_MAX_LEN;
1522
1523 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1524 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1525
1526 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1527 le32_to_cpu(ex2->ee_block))
1528 return 0;
1529
1530 /*
1531 * To allow future support for preallocated extents to be added
1532 * as an RO_COMPAT feature, refuse to merge to extents if
1533 * this can result in the top bit of ee_len being set.
1534 */
1535 if (ext1_ee_len + ext2_ee_len > max_len)
1536 return 0;
1537#ifdef AGGRESSIVE_TEST
1538 if (ext1_ee_len >= 4)
1539 return 0;
1540#endif
1541
1542 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1543 return 1;
1544 return 0;
1545}
1546
1547/*
1548 * This function tries to merge the "ex" extent to the next extent in the tree.
1549 * It always tries to merge towards right. If you want to merge towards
1550 * left, pass "ex - 1" as argument instead of "ex".
1551 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1552 * 1 if they got merged.
1553 */
1554static int ext4_ext_try_to_merge_right(struct inode *inode,
1555 struct ext4_ext_path *path,
1556 struct ext4_extent *ex)
1557{
1558 struct ext4_extent_header *eh;
1559 unsigned int depth, len;
1560 int merge_done = 0;
1561 int uninitialized = 0;
1562
1563 depth = ext_depth(inode);
1564 BUG_ON(path[depth].p_hdr == NULL);
1565 eh = path[depth].p_hdr;
1566
1567 while (ex < EXT_LAST_EXTENT(eh)) {
1568 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1569 break;
1570 /* merge with next extent! */
1571 if (ext4_ext_is_uninitialized(ex))
1572 uninitialized = 1;
1573 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1574 + ext4_ext_get_actual_len(ex + 1));
1575 if (uninitialized)
1576 ext4_ext_mark_uninitialized(ex);
1577
1578 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1579 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1580 * sizeof(struct ext4_extent);
1581 memmove(ex + 1, ex + 2, len);
1582 }
1583 le16_add_cpu(&eh->eh_entries, -1);
1584 merge_done = 1;
1585 WARN_ON(eh->eh_entries == 0);
1586 if (!eh->eh_entries)
1587 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1588 }
1589
1590 return merge_done;
1591}
1592
1593/*
1594 * This function tries to merge the @ex extent to neighbours in the tree.
1595 * return 1 if merge left else 0.
1596 */
1597static int ext4_ext_try_to_merge(struct inode *inode,
1598 struct ext4_ext_path *path,
1599 struct ext4_extent *ex) {
1600 struct ext4_extent_header *eh;
1601 unsigned int depth;
1602 int merge_done = 0;
1603 int ret = 0;
1604
1605 depth = ext_depth(inode);
1606 BUG_ON(path[depth].p_hdr == NULL);
1607 eh = path[depth].p_hdr;
1608
1609 if (ex > EXT_FIRST_EXTENT(eh))
1610 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1611
1612 if (!merge_done)
1613 ret = ext4_ext_try_to_merge_right(inode, path, ex);
1614
1615 return ret;
1616}
1617
1618/*
1619 * check if a portion of the "newext" extent overlaps with an
1620 * existing extent.
1621 *
1622 * If there is an overlap discovered, it updates the length of the newext
1623 * such that there will be no overlap, and then returns 1.
1624 * If there is no overlap found, it returns 0.
1625 */
1626static unsigned int ext4_ext_check_overlap(struct inode *inode,
1627 struct ext4_extent *newext,
1628 struct ext4_ext_path *path)
1629{
1630 ext4_lblk_t b1, b2;
1631 unsigned int depth, len1;
1632 unsigned int ret = 0;
1633
1634 b1 = le32_to_cpu(newext->ee_block);
1635 len1 = ext4_ext_get_actual_len(newext);
1636 depth = ext_depth(inode);
1637 if (!path[depth].p_ext)
1638 goto out;
1639 b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1640
1641 /*
1642 * get the next allocated block if the extent in the path
1643 * is before the requested block(s)
1644 */
1645 if (b2 < b1) {
1646 b2 = ext4_ext_next_allocated_block(path);
1647 if (b2 == EXT_MAX_BLOCKS)
1648 goto out;
1649 }
1650
1651 /* check for wrap through zero on extent logical start block*/
1652 if (b1 + len1 < b1) {
1653 len1 = EXT_MAX_BLOCKS - b1;
1654 newext->ee_len = cpu_to_le16(len1);
1655 ret = 1;
1656 }
1657
1658 /* check for overlap */
1659 if (b1 + len1 > b2) {
1660 newext->ee_len = cpu_to_le16(b2 - b1);
1661 ret = 1;
1662 }
1663out:
1664 return ret;
1665}
1666
1667/*
1668 * ext4_ext_insert_extent:
1669 * tries to merge requsted extent into the existing extent or
1670 * inserts requested extent as new one into the tree,
1671 * creating new leaf in the no-space case.
1672 */
1673int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1674 struct ext4_ext_path *path,
1675 struct ext4_extent *newext, int flag)
1676{
1677 struct ext4_extent_header *eh;
1678 struct ext4_extent *ex, *fex;
1679 struct ext4_extent *nearex; /* nearest extent */
1680 struct ext4_ext_path *npath = NULL;
1681 int depth, len, err;
1682 ext4_lblk_t next;
1683 unsigned uninitialized = 0;
1684 int flags = 0;
1685
1686 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1687 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1688 return -EIO;
1689 }
1690 depth = ext_depth(inode);
1691 ex = path[depth].p_ext;
1692 if (unlikely(path[depth].p_hdr == NULL)) {
1693 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1694 return -EIO;
1695 }
1696
1697 /* try to insert block into found extent and return */
1698 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
1699 && ext4_can_extents_be_merged(inode, ex, newext)) {
1700 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
1701 ext4_ext_is_uninitialized(newext),
1702 ext4_ext_get_actual_len(newext),
1703 le32_to_cpu(ex->ee_block),
1704 ext4_ext_is_uninitialized(ex),
1705 ext4_ext_get_actual_len(ex),
1706 ext4_ext_pblock(ex));
1707 err = ext4_ext_get_access(handle, inode, path + depth);
1708 if (err)
1709 return err;
1710
1711 /*
1712 * ext4_can_extents_be_merged should have checked that either
1713 * both extents are uninitialized, or both aren't. Thus we
1714 * need to check only one of them here.
1715 */
1716 if (ext4_ext_is_uninitialized(ex))
1717 uninitialized = 1;
1718 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1719 + ext4_ext_get_actual_len(newext));
1720 if (uninitialized)
1721 ext4_ext_mark_uninitialized(ex);
1722 eh = path[depth].p_hdr;
1723 nearex = ex;
1724 goto merge;
1725 }
1726
1727 depth = ext_depth(inode);
1728 eh = path[depth].p_hdr;
1729 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1730 goto has_space;
1731
1732 /* probably next leaf has space for us? */
1733 fex = EXT_LAST_EXTENT(eh);
1734 next = EXT_MAX_BLOCKS;
1735 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1736 next = ext4_ext_next_leaf_block(path);
1737 if (next != EXT_MAX_BLOCKS) {
1738 ext_debug("next leaf block - %d\n", next);
1739 BUG_ON(npath != NULL);
1740 npath = ext4_ext_find_extent(inode, next, NULL);
1741 if (IS_ERR(npath))
1742 return PTR_ERR(npath);
1743 BUG_ON(npath->p_depth != path->p_depth);
1744 eh = npath[depth].p_hdr;
1745 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1746 ext_debug("next leaf isn't full(%d)\n",
1747 le16_to_cpu(eh->eh_entries));
1748 path = npath;
1749 goto has_space;
1750 }
1751 ext_debug("next leaf has no free space(%d,%d)\n",
1752 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1753 }
1754
1755 /*
1756 * There is no free space in the found leaf.
1757 * We're gonna add a new leaf in the tree.
1758 */
1759 if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
1760 flags = EXT4_MB_USE_ROOT_BLOCKS;
1761 err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
1762 if (err)
1763 goto cleanup;
1764 depth = ext_depth(inode);
1765 eh = path[depth].p_hdr;
1766
1767has_space:
1768 nearex = path[depth].p_ext;
1769
1770 err = ext4_ext_get_access(handle, inode, path + depth);
1771 if (err)
1772 goto cleanup;
1773
1774 if (!nearex) {
1775 /* there is no extent in this leaf, create first one */
1776 ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n",
1777 le32_to_cpu(newext->ee_block),
1778 ext4_ext_pblock(newext),
1779 ext4_ext_is_uninitialized(newext),
1780 ext4_ext_get_actual_len(newext));
1781 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1782 } else if (le32_to_cpu(newext->ee_block)
1783 > le32_to_cpu(nearex->ee_block)) {
1784/* BUG_ON(newext->ee_block == nearex->ee_block); */
1785 if (nearex != EXT_LAST_EXTENT(eh)) {
1786 len = EXT_MAX_EXTENT(eh) - nearex;
1787 len = (len - 1) * sizeof(struct ext4_extent);
1788 len = len < 0 ? 0 : len;
1789 ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, "
1790 "move %d from 0x%p to 0x%p\n",
1791 le32_to_cpu(newext->ee_block),
1792 ext4_ext_pblock(newext),
1793 ext4_ext_is_uninitialized(newext),
1794 ext4_ext_get_actual_len(newext),
1795 nearex, len, nearex + 1, nearex + 2);
1796 memmove(nearex + 2, nearex + 1, len);
1797 }
1798 path[depth].p_ext = nearex + 1;
1799 } else {
1800 BUG_ON(newext->ee_block == nearex->ee_block);
1801 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1802 len = len < 0 ? 0 : len;
1803 ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, "
1804 "move %d from 0x%p to 0x%p\n",
1805 le32_to_cpu(newext->ee_block),
1806 ext4_ext_pblock(newext),
1807 ext4_ext_is_uninitialized(newext),
1808 ext4_ext_get_actual_len(newext),
1809 nearex, len, nearex, nearex + 1);
1810 memmove(nearex + 1, nearex, len);
1811 path[depth].p_ext = nearex;
1812 }
1813
1814 le16_add_cpu(&eh->eh_entries, 1);
1815 nearex = path[depth].p_ext;
1816 nearex->ee_block = newext->ee_block;
1817 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
1818 nearex->ee_len = newext->ee_len;
1819
1820merge:
1821 /* try to merge extents to the right */
1822 if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
1823 ext4_ext_try_to_merge(inode, path, nearex);
1824
1825 /* try to merge extents to the left */
1826
1827 /* time to correct all indexes above */
1828 err = ext4_ext_correct_indexes(handle, inode, path);
1829 if (err)
1830 goto cleanup;
1831
1832 err = ext4_ext_dirty(handle, inode, path + depth);
1833
1834cleanup:
1835 if (npath) {
1836 ext4_ext_drop_refs(npath);
1837 kfree(npath);
1838 }
1839 ext4_ext_invalidate_cache(inode);
1840 return err;
1841}
1842
1843static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1844 ext4_lblk_t num, ext_prepare_callback func,
1845 void *cbdata)
1846{
1847 struct ext4_ext_path *path = NULL;
1848 struct ext4_ext_cache cbex;
1849 struct ext4_extent *ex;
1850 ext4_lblk_t next, start = 0, end = 0;
1851 ext4_lblk_t last = block + num;
1852 int depth, exists, err = 0;
1853
1854 BUG_ON(func == NULL);
1855 BUG_ON(inode == NULL);
1856
1857 while (block < last && block != EXT_MAX_BLOCKS) {
1858 num = last - block;
1859 /* find extent for this block */
1860 down_read(&EXT4_I(inode)->i_data_sem);
1861 path = ext4_ext_find_extent(inode, block, path);
1862 up_read(&EXT4_I(inode)->i_data_sem);
1863 if (IS_ERR(path)) {
1864 err = PTR_ERR(path);
1865 path = NULL;
1866 break;
1867 }
1868
1869 depth = ext_depth(inode);
1870 if (unlikely(path[depth].p_hdr == NULL)) {
1871 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1872 err = -EIO;
1873 break;
1874 }
1875 ex = path[depth].p_ext;
1876 next = ext4_ext_next_allocated_block(path);
1877
1878 exists = 0;
1879 if (!ex) {
1880 /* there is no extent yet, so try to allocate
1881 * all requested space */
1882 start = block;
1883 end = block + num;
1884 } else if (le32_to_cpu(ex->ee_block) > block) {
1885 /* need to allocate space before found extent */
1886 start = block;
1887 end = le32_to_cpu(ex->ee_block);
1888 if (block + num < end)
1889 end = block + num;
1890 } else if (block >= le32_to_cpu(ex->ee_block)
1891 + ext4_ext_get_actual_len(ex)) {
1892 /* need to allocate space after found extent */
1893 start = block;
1894 end = block + num;
1895 if (end >= next)
1896 end = next;
1897 } else if (block >= le32_to_cpu(ex->ee_block)) {
1898 /*
1899 * some part of requested space is covered
1900 * by found extent
1901 */
1902 start = block;
1903 end = le32_to_cpu(ex->ee_block)
1904 + ext4_ext_get_actual_len(ex);
1905 if (block + num < end)
1906 end = block + num;
1907 exists = 1;
1908 } else {
1909 BUG();
1910 }
1911 BUG_ON(end <= start);
1912
1913 if (!exists) {
1914 cbex.ec_block = start;
1915 cbex.ec_len = end - start;
1916 cbex.ec_start = 0;
1917 } else {
1918 cbex.ec_block = le32_to_cpu(ex->ee_block);
1919 cbex.ec_len = ext4_ext_get_actual_len(ex);
1920 cbex.ec_start = ext4_ext_pblock(ex);
1921 }
1922
1923 if (unlikely(cbex.ec_len == 0)) {
1924 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
1925 err = -EIO;
1926 break;
1927 }
1928 err = func(inode, next, &cbex, ex, cbdata);
1929 ext4_ext_drop_refs(path);
1930
1931 if (err < 0)
1932 break;
1933
1934 if (err == EXT_REPEAT)
1935 continue;
1936 else if (err == EXT_BREAK) {
1937 err = 0;
1938 break;
1939 }
1940
1941 if (ext_depth(inode) != depth) {
1942 /* depth was changed. we have to realloc path */
1943 kfree(path);
1944 path = NULL;
1945 }
1946
1947 block = cbex.ec_block + cbex.ec_len;
1948 }
1949
1950 if (path) {
1951 ext4_ext_drop_refs(path);
1952 kfree(path);
1953 }
1954
1955 return err;
1956}
1957
1958static void
1959ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1960 __u32 len, ext4_fsblk_t start)
1961{
1962 struct ext4_ext_cache *cex;
1963 BUG_ON(len == 0);
1964 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1965 cex = &EXT4_I(inode)->i_cached_extent;
1966 cex->ec_block = block;
1967 cex->ec_len = len;
1968 cex->ec_start = start;
1969 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1970}
1971
1972/*
1973 * ext4_ext_put_gap_in_cache:
1974 * calculate boundaries of the gap that the requested block fits into
1975 * and cache this gap
1976 */
1977static void
1978ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1979 ext4_lblk_t block)
1980{
1981 int depth = ext_depth(inode);
1982 unsigned long len;
1983 ext4_lblk_t lblock;
1984 struct ext4_extent *ex;
1985
1986 ex = path[depth].p_ext;
1987 if (ex == NULL) {
1988 /* there is no extent yet, so gap is [0;-] */
1989 lblock = 0;
1990 len = EXT_MAX_BLOCKS;
1991 ext_debug("cache gap(whole file):");
1992 } else if (block < le32_to_cpu(ex->ee_block)) {
1993 lblock = block;
1994 len = le32_to_cpu(ex->ee_block) - block;
1995 ext_debug("cache gap(before): %u [%u:%u]",
1996 block,
1997 le32_to_cpu(ex->ee_block),
1998 ext4_ext_get_actual_len(ex));
1999 } else if (block >= le32_to_cpu(ex->ee_block)
2000 + ext4_ext_get_actual_len(ex)) {
2001 ext4_lblk_t next;
2002 lblock = le32_to_cpu(ex->ee_block)
2003 + ext4_ext_get_actual_len(ex);
2004
2005 next = ext4_ext_next_allocated_block(path);
2006 ext_debug("cache gap(after): [%u:%u] %u",
2007 le32_to_cpu(ex->ee_block),
2008 ext4_ext_get_actual_len(ex),
2009 block);
2010 BUG_ON(next == lblock);
2011 len = next - lblock;
2012 } else {
2013 lblock = len = 0;
2014 BUG();
2015 }
2016
2017 ext_debug(" -> %u:%lu\n", lblock, len);
2018 ext4_ext_put_in_cache(inode, lblock, len, 0);
2019}
2020
2021/*
2022 * ext4_ext_check_cache()
2023 * Checks to see if the given block is in the cache.
2024 * If it is, the cached extent is stored in the given
2025 * cache extent pointer. If the cached extent is a hole,
2026 * this routine should be used instead of
2027 * ext4_ext_in_cache if the calling function needs to
2028 * know the size of the hole.
2029 *
2030 * @inode: The files inode
2031 * @block: The block to look for in the cache
2032 * @ex: Pointer where the cached extent will be stored
2033 * if it contains block
2034 *
2035 * Return 0 if cache is invalid; 1 if the cache is valid
2036 */
2037static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block,
2038 struct ext4_ext_cache *ex){
2039 struct ext4_ext_cache *cex;
2040 struct ext4_sb_info *sbi;
2041 int ret = 0;
2042
2043 /*
2044 * We borrow i_block_reservation_lock to protect i_cached_extent
2045 */
2046 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
2047 cex = &EXT4_I(inode)->i_cached_extent;
2048 sbi = EXT4_SB(inode->i_sb);
2049
2050 /* has cache valid data? */
2051 if (cex->ec_len == 0)
2052 goto errout;
2053
2054 if (in_range(block, cex->ec_block, cex->ec_len)) {
2055 memcpy(ex, cex, sizeof(struct ext4_ext_cache));
2056 ext_debug("%u cached by %u:%u:%llu\n",
2057 block,
2058 cex->ec_block, cex->ec_len, cex->ec_start);
2059 ret = 1;
2060 }
2061errout:
2062 if (!ret)
2063 sbi->extent_cache_misses++;
2064 else
2065 sbi->extent_cache_hits++;
2066 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
2067 return ret;
2068}
2069
2070/*
2071 * ext4_ext_in_cache()
2072 * Checks to see if the given block is in the cache.
2073 * If it is, the cached extent is stored in the given
2074 * extent pointer.
2075 *
2076 * @inode: The files inode
2077 * @block: The block to look for in the cache
2078 * @ex: Pointer where the cached extent will be stored
2079 * if it contains block
2080 *
2081 * Return 0 if cache is invalid; 1 if the cache is valid
2082 */
2083static int
2084ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
2085 struct ext4_extent *ex)
2086{
2087 struct ext4_ext_cache cex;
2088 int ret = 0;
2089
2090 if (ext4_ext_check_cache(inode, block, &cex)) {
2091 ex->ee_block = cpu_to_le32(cex.ec_block);
2092 ext4_ext_store_pblock(ex, cex.ec_start);
2093 ex->ee_len = cpu_to_le16(cex.ec_len);
2094 ret = 1;
2095 }
2096
2097 return ret;
2098}
2099
2100
2101/*
2102 * ext4_ext_rm_idx:
2103 * removes index from the index block.
2104 */
2105static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2106 struct ext4_ext_path *path)
2107{
2108 int err;
2109 ext4_fsblk_t leaf;
2110
2111 /* free index block */
2112 path--;
2113 leaf = ext4_idx_pblock(path->p_idx);
2114 if (unlikely(path->p_hdr->eh_entries == 0)) {
2115 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2116 return -EIO;
2117 }
2118 err = ext4_ext_get_access(handle, inode, path);
2119 if (err)
2120 return err;
2121
2122 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2123 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2124 len *= sizeof(struct ext4_extent_idx);
2125 memmove(path->p_idx, path->p_idx + 1, len);
2126 }
2127
2128 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2129 err = ext4_ext_dirty(handle, inode, path);
2130 if (err)
2131 return err;
2132 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2133 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2134 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2135 return err;
2136}
2137
2138/*
2139 * ext4_ext_calc_credits_for_single_extent:
2140 * This routine returns max. credits that needed to insert an extent
2141 * to the extent tree.
2142 * When pass the actual path, the caller should calculate credits
2143 * under i_data_sem.
2144 */
2145int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2146 struct ext4_ext_path *path)
2147{
2148 if (path) {
2149 int depth = ext_depth(inode);
2150 int ret = 0;
2151
2152 /* probably there is space in leaf? */
2153 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2154 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2155
2156 /*
2157 * There are some space in the leaf tree, no
2158 * need to account for leaf block credit
2159 *
2160 * bitmaps and block group descriptor blocks
2161 * and other metadat blocks still need to be
2162 * accounted.
2163 */
2164 /* 1 bitmap, 1 block group descriptor */
2165 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2166 return ret;
2167 }
2168 }
2169
2170 return ext4_chunk_trans_blocks(inode, nrblocks);
2171}
2172
2173/*
2174 * How many index/leaf blocks need to change/allocate to modify nrblocks?
2175 *
2176 * if nrblocks are fit in a single extent (chunk flag is 1), then
2177 * in the worse case, each tree level index/leaf need to be changed
2178 * if the tree split due to insert a new extent, then the old tree
2179 * index/leaf need to be updated too
2180 *
2181 * If the nrblocks are discontiguous, they could cause
2182 * the whole tree split more than once, but this is really rare.
2183 */
2184int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2185{
2186 int index;
2187 int depth = ext_depth(inode);
2188
2189 if (chunk)
2190 index = depth * 2;
2191 else
2192 index = depth * 3;
2193
2194 return index;
2195}
2196
2197static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2198 struct ext4_extent *ex,
2199 ext4_lblk_t from, ext4_lblk_t to)
2200{
2201 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2202 int flags = EXT4_FREE_BLOCKS_FORGET;
2203
2204 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2205 flags |= EXT4_FREE_BLOCKS_METADATA;
2206#ifdef EXTENTS_STATS
2207 {
2208 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2209 spin_lock(&sbi->s_ext_stats_lock);
2210 sbi->s_ext_blocks += ee_len;
2211 sbi->s_ext_extents++;
2212 if (ee_len < sbi->s_ext_min)
2213 sbi->s_ext_min = ee_len;
2214 if (ee_len > sbi->s_ext_max)
2215 sbi->s_ext_max = ee_len;
2216 if (ext_depth(inode) > sbi->s_depth_max)
2217 sbi->s_depth_max = ext_depth(inode);
2218 spin_unlock(&sbi->s_ext_stats_lock);
2219 }
2220#endif
2221 if (from >= le32_to_cpu(ex->ee_block)
2222 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2223 /* tail removal */
2224 ext4_lblk_t num;
2225 ext4_fsblk_t start;
2226
2227 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2228 start = ext4_ext_pblock(ex) + ee_len - num;
2229 ext_debug("free last %u blocks starting %llu\n", num, start);
2230 ext4_free_blocks(handle, inode, NULL, start, num, flags);
2231 } else if (from == le32_to_cpu(ex->ee_block)
2232 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2233 /* head removal */
2234 ext4_lblk_t num;
2235 ext4_fsblk_t start;
2236
2237 num = to - from;
2238 start = ext4_ext_pblock(ex);
2239
2240 ext_debug("free first %u blocks starting %llu\n", num, start);
2241 ext4_free_blocks(handle, inode, 0, start, num, flags);
2242
2243 } else {
2244 printk(KERN_INFO "strange request: removal(2) "
2245 "%u-%u from %u:%u\n",
2246 from, to, le32_to_cpu(ex->ee_block), ee_len);
2247 }
2248 return 0;
2249}
2250
2251
2252/*
2253 * ext4_ext_rm_leaf() Removes the extents associated with the
2254 * blocks appearing between "start" and "end", and splits the extents
2255 * if "start" and "end" appear in the same extent
2256 *
2257 * @handle: The journal handle
2258 * @inode: The files inode
2259 * @path: The path to the leaf
2260 * @start: The first block to remove
2261 * @end: The last block to remove
2262 */
2263static int
2264ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2265 struct ext4_ext_path *path, ext4_lblk_t start,
2266 ext4_lblk_t end)
2267{
2268 int err = 0, correct_index = 0;
2269 int depth = ext_depth(inode), credits;
2270 struct ext4_extent_header *eh;
2271 ext4_lblk_t a, b, block;
2272 unsigned num;
2273 ext4_lblk_t ex_ee_block;
2274 unsigned short ex_ee_len;
2275 unsigned uninitialized = 0;
2276 struct ext4_extent *ex;
2277 struct ext4_map_blocks map;
2278
2279 /* the header must be checked already in ext4_ext_remove_space() */
2280 ext_debug("truncate since %u in leaf\n", start);
2281 if (!path[depth].p_hdr)
2282 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2283 eh = path[depth].p_hdr;
2284 if (unlikely(path[depth].p_hdr == NULL)) {
2285 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2286 return -EIO;
2287 }
2288 /* find where to start removing */
2289 ex = EXT_LAST_EXTENT(eh);
2290
2291 ex_ee_block = le32_to_cpu(ex->ee_block);
2292 ex_ee_len = ext4_ext_get_actual_len(ex);
2293
2294 while (ex >= EXT_FIRST_EXTENT(eh) &&
2295 ex_ee_block + ex_ee_len > start) {
2296
2297 if (ext4_ext_is_uninitialized(ex))
2298 uninitialized = 1;
2299 else
2300 uninitialized = 0;
2301
2302 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2303 uninitialized, ex_ee_len);
2304 path[depth].p_ext = ex;
2305
2306 a = ex_ee_block > start ? ex_ee_block : start;
2307 b = ex_ee_block+ex_ee_len - 1 < end ?
2308 ex_ee_block+ex_ee_len - 1 : end;
2309
2310 ext_debug(" border %u:%u\n", a, b);
2311
2312 /* If this extent is beyond the end of the hole, skip it */
2313 if (end <= ex_ee_block) {
2314 ex--;
2315 ex_ee_block = le32_to_cpu(ex->ee_block);
2316 ex_ee_len = ext4_ext_get_actual_len(ex);
2317 continue;
2318 } else if (a != ex_ee_block &&
2319 b != ex_ee_block + ex_ee_len - 1) {
2320 /*
2321 * If this is a truncate, then this condition should
2322 * never happen because at least one of the end points
2323 * needs to be on the edge of the extent.
2324 */
2325 if (end == EXT_MAX_BLOCKS - 1) {
2326 ext_debug(" bad truncate %u:%u\n",
2327 start, end);
2328 block = 0;
2329 num = 0;
2330 err = -EIO;
2331 goto out;
2332 }
2333 /*
2334 * else this is a hole punch, so the extent needs to
2335 * be split since neither edge of the hole is on the
2336 * extent edge
2337 */
2338 else{
2339 map.m_pblk = ext4_ext_pblock(ex);
2340 map.m_lblk = ex_ee_block;
2341 map.m_len = b - ex_ee_block;
2342
2343 err = ext4_split_extent(handle,
2344 inode, path, &map, 0,
2345 EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
2346 EXT4_GET_BLOCKS_PRE_IO);
2347
2348 if (err < 0)
2349 goto out;
2350
2351 ex_ee_len = ext4_ext_get_actual_len(ex);
2352
2353 b = ex_ee_block+ex_ee_len - 1 < end ?
2354 ex_ee_block+ex_ee_len - 1 : end;
2355
2356 /* Then remove tail of this extent */
2357 block = ex_ee_block;
2358 num = a - block;
2359 }
2360 } else if (a != ex_ee_block) {
2361 /* remove tail of the extent */
2362 block = ex_ee_block;
2363 num = a - block;
2364 } else if (b != ex_ee_block + ex_ee_len - 1) {
2365 /* remove head of the extent */
2366 block = b;
2367 num = ex_ee_block + ex_ee_len - b;
2368
2369 /*
2370 * If this is a truncate, this condition
2371 * should never happen
2372 */
2373 if (end == EXT_MAX_BLOCKS - 1) {
2374 ext_debug(" bad truncate %u:%u\n",
2375 start, end);
2376 err = -EIO;
2377 goto out;
2378 }
2379 } else {
2380 /* remove whole extent: excellent! */
2381 block = ex_ee_block;
2382 num = 0;
2383 if (a != ex_ee_block) {
2384 ext_debug(" bad truncate %u:%u\n",
2385 start, end);
2386 err = -EIO;
2387 goto out;
2388 }
2389
2390 if (b != ex_ee_block + ex_ee_len - 1) {
2391 ext_debug(" bad truncate %u:%u\n",
2392 start, end);
2393 err = -EIO;
2394 goto out;
2395 }
2396 }
2397
2398 /*
2399 * 3 for leaf, sb, and inode plus 2 (bmap and group
2400 * descriptor) for each block group; assume two block
2401 * groups plus ex_ee_len/blocks_per_block_group for
2402 * the worst case
2403 */
2404 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2405 if (ex == EXT_FIRST_EXTENT(eh)) {
2406 correct_index = 1;
2407 credits += (ext_depth(inode)) + 1;
2408 }
2409 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2410
2411 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2412 if (err)
2413 goto out;
2414
2415 err = ext4_ext_get_access(handle, inode, path + depth);
2416 if (err)
2417 goto out;
2418
2419 err = ext4_remove_blocks(handle, inode, ex, a, b);
2420 if (err)
2421 goto out;
2422
2423 if (num == 0) {
2424 /* this extent is removed; mark slot entirely unused */
2425 ext4_ext_store_pblock(ex, 0);
2426 } else if (block != ex_ee_block) {
2427 /*
2428 * If this was a head removal, then we need to update
2429 * the physical block since it is now at a different
2430 * location
2431 */
2432 ext4_ext_store_pblock(ex, ext4_ext_pblock(ex) + (b-a));
2433 }
2434
2435 ex->ee_block = cpu_to_le32(block);
2436 ex->ee_len = cpu_to_le16(num);
2437 /*
2438 * Do not mark uninitialized if all the blocks in the
2439 * extent have been removed.
2440 */
2441 if (uninitialized && num)
2442 ext4_ext_mark_uninitialized(ex);
2443
2444 err = ext4_ext_dirty(handle, inode, path + depth);
2445 if (err)
2446 goto out;
2447
2448 /*
2449 * If the extent was completely released,
2450 * we need to remove it from the leaf
2451 */
2452 if (num == 0) {
2453 if (end != EXT_MAX_BLOCKS - 1) {
2454 /*
2455 * For hole punching, we need to scoot all the
2456 * extents up when an extent is removed so that
2457 * we dont have blank extents in the middle
2458 */
2459 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2460 sizeof(struct ext4_extent));
2461
2462 /* Now get rid of the one at the end */
2463 memset(EXT_LAST_EXTENT(eh), 0,
2464 sizeof(struct ext4_extent));
2465 }
2466 le16_add_cpu(&eh->eh_entries, -1);
2467 }
2468
2469 ext_debug("new extent: %u:%u:%llu\n", block, num,
2470 ext4_ext_pblock(ex));
2471 ex--;
2472 ex_ee_block = le32_to_cpu(ex->ee_block);
2473 ex_ee_len = ext4_ext_get_actual_len(ex);
2474 }
2475
2476 if (correct_index && eh->eh_entries)
2477 err = ext4_ext_correct_indexes(handle, inode, path);
2478
2479 /* if this leaf is free, then we should
2480 * remove it from index block above */
2481 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2482 err = ext4_ext_rm_idx(handle, inode, path + depth);
2483
2484out:
2485 return err;
2486}
2487
2488/*
2489 * ext4_ext_more_to_rm:
2490 * returns 1 if current index has to be freed (even partial)
2491 */
2492static int
2493ext4_ext_more_to_rm(struct ext4_ext_path *path)
2494{
2495 BUG_ON(path->p_idx == NULL);
2496
2497 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2498 return 0;
2499
2500 /*
2501 * if truncate on deeper level happened, it wasn't partial,
2502 * so we have to consider current index for truncation
2503 */
2504 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2505 return 0;
2506 return 1;
2507}
2508
2509static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
2510{
2511 struct super_block *sb = inode->i_sb;
2512 int depth = ext_depth(inode);
2513 struct ext4_ext_path *path;
2514 handle_t *handle;
2515 int i, err;
2516
2517 ext_debug("truncate since %u\n", start);
2518
2519 /* probably first extent we're gonna free will be last in block */
2520 handle = ext4_journal_start(inode, depth + 1);
2521 if (IS_ERR(handle))
2522 return PTR_ERR(handle);
2523
2524again:
2525 ext4_ext_invalidate_cache(inode);
2526
2527 /*
2528 * We start scanning from right side, freeing all the blocks
2529 * after i_size and walking into the tree depth-wise.
2530 */
2531 depth = ext_depth(inode);
2532 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
2533 if (path == NULL) {
2534 ext4_journal_stop(handle);
2535 return -ENOMEM;
2536 }
2537 path[0].p_depth = depth;
2538 path[0].p_hdr = ext_inode_hdr(inode);
2539 if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2540 err = -EIO;
2541 goto out;
2542 }
2543 i = err = 0;
2544
2545 while (i >= 0 && err == 0) {
2546 if (i == depth) {
2547 /* this is leaf block */
2548 err = ext4_ext_rm_leaf(handle, inode, path,
2549 start, EXT_MAX_BLOCKS - 1);
2550 /* root level has p_bh == NULL, brelse() eats this */
2551 brelse(path[i].p_bh);
2552 path[i].p_bh = NULL;
2553 i--;
2554 continue;
2555 }
2556
2557 /* this is index block */
2558 if (!path[i].p_hdr) {
2559 ext_debug("initialize header\n");
2560 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2561 }
2562
2563 if (!path[i].p_idx) {
2564 /* this level hasn't been touched yet */
2565 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2566 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2567 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2568 path[i].p_hdr,
2569 le16_to_cpu(path[i].p_hdr->eh_entries));
2570 } else {
2571 /* we were already here, see at next index */
2572 path[i].p_idx--;
2573 }
2574
2575 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2576 i, EXT_FIRST_INDEX(path[i].p_hdr),
2577 path[i].p_idx);
2578 if (ext4_ext_more_to_rm(path + i)) {
2579 struct buffer_head *bh;
2580 /* go to the next level */
2581 ext_debug("move to level %d (block %llu)\n",
2582 i + 1, ext4_idx_pblock(path[i].p_idx));
2583 memset(path + i + 1, 0, sizeof(*path));
2584 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
2585 if (!bh) {
2586 /* should we reset i_size? */
2587 err = -EIO;
2588 break;
2589 }
2590 if (WARN_ON(i + 1 > depth)) {
2591 err = -EIO;
2592 break;
2593 }
2594 if (ext4_ext_check(inode, ext_block_hdr(bh),
2595 depth - i - 1)) {
2596 err = -EIO;
2597 break;
2598 }
2599 path[i + 1].p_bh = bh;
2600
2601 /* save actual number of indexes since this
2602 * number is changed at the next iteration */
2603 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2604 i++;
2605 } else {
2606 /* we finished processing this index, go up */
2607 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2608 /* index is empty, remove it;
2609 * handle must be already prepared by the
2610 * truncatei_leaf() */
2611 err = ext4_ext_rm_idx(handle, inode, path + i);
2612 }
2613 /* root level has p_bh == NULL, brelse() eats this */
2614 brelse(path[i].p_bh);
2615 path[i].p_bh = NULL;
2616 i--;
2617 ext_debug("return to level %d\n", i);
2618 }
2619 }
2620
2621 /* TODO: flexible tree reduction should be here */
2622 if (path->p_hdr->eh_entries == 0) {
2623 /*
2624 * truncate to zero freed all the tree,
2625 * so we need to correct eh_depth
2626 */
2627 err = ext4_ext_get_access(handle, inode, path);
2628 if (err == 0) {
2629 ext_inode_hdr(inode)->eh_depth = 0;
2630 ext_inode_hdr(inode)->eh_max =
2631 cpu_to_le16(ext4_ext_space_root(inode, 0));
2632 err = ext4_ext_dirty(handle, inode, path);
2633 }
2634 }
2635out:
2636 ext4_ext_drop_refs(path);
2637 kfree(path);
2638 if (err == -EAGAIN)
2639 goto again;
2640 ext4_journal_stop(handle);
2641
2642 return err;
2643}
2644
2645/*
2646 * called at mount time
2647 */
2648void ext4_ext_init(struct super_block *sb)
2649{
2650 /*
2651 * possible initialization would be here
2652 */
2653
2654 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2655#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
2656 printk(KERN_INFO "EXT4-fs: file extents enabled");
2657#ifdef AGGRESSIVE_TEST
2658 printk(", aggressive tests");
2659#endif
2660#ifdef CHECK_BINSEARCH
2661 printk(", check binsearch");
2662#endif
2663#ifdef EXTENTS_STATS
2664 printk(", stats");
2665#endif
2666 printk("\n");
2667#endif
2668#ifdef EXTENTS_STATS
2669 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2670 EXT4_SB(sb)->s_ext_min = 1 << 30;
2671 EXT4_SB(sb)->s_ext_max = 0;
2672#endif
2673 }
2674}
2675
2676/*
2677 * called at umount time
2678 */
2679void ext4_ext_release(struct super_block *sb)
2680{
2681 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2682 return;
2683
2684#ifdef EXTENTS_STATS
2685 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2686 struct ext4_sb_info *sbi = EXT4_SB(sb);
2687 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2688 sbi->s_ext_blocks, sbi->s_ext_extents,
2689 sbi->s_ext_blocks / sbi->s_ext_extents);
2690 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2691 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2692 }
2693#endif
2694}
2695
2696/* FIXME!! we need to try to merge to left or right after zero-out */
2697static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2698{
2699 ext4_fsblk_t ee_pblock;
2700 unsigned int ee_len;
2701 int ret;
2702
2703 ee_len = ext4_ext_get_actual_len(ex);
2704 ee_pblock = ext4_ext_pblock(ex);
2705
2706 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
2707 if (ret > 0)
2708 ret = 0;
2709
2710 return ret;
2711}
2712
2713/*
2714 * used by extent splitting.
2715 */
2716#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
2717 due to ENOSPC */
2718#define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */
2719#define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */
2720
2721/*
2722 * ext4_split_extent_at() splits an extent at given block.
2723 *
2724 * @handle: the journal handle
2725 * @inode: the file inode
2726 * @path: the path to the extent
2727 * @split: the logical block where the extent is splitted.
2728 * @split_flags: indicates if the extent could be zeroout if split fails, and
2729 * the states(init or uninit) of new extents.
2730 * @flags: flags used to insert new extent to extent tree.
2731 *
2732 *
2733 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
2734 * of which are deterimined by split_flag.
2735 *
2736 * There are two cases:
2737 * a> the extent are splitted into two extent.
2738 * b> split is not needed, and just mark the extent.
2739 *
2740 * return 0 on success.
2741 */
2742static int ext4_split_extent_at(handle_t *handle,
2743 struct inode *inode,
2744 struct ext4_ext_path *path,
2745 ext4_lblk_t split,
2746 int split_flag,
2747 int flags)
2748{
2749 ext4_fsblk_t newblock;
2750 ext4_lblk_t ee_block;
2751 struct ext4_extent *ex, newex, orig_ex;
2752 struct ext4_extent *ex2 = NULL;
2753 unsigned int ee_len, depth;
2754 int err = 0;
2755
2756 ext_debug("ext4_split_extents_at: inode %lu, logical"
2757 "block %llu\n", inode->i_ino, (unsigned long long)split);
2758
2759 ext4_ext_show_leaf(inode, path);
2760
2761 depth = ext_depth(inode);
2762 ex = path[depth].p_ext;
2763 ee_block = le32_to_cpu(ex->ee_block);
2764 ee_len = ext4_ext_get_actual_len(ex);
2765 newblock = split - ee_block + ext4_ext_pblock(ex);
2766
2767 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
2768
2769 err = ext4_ext_get_access(handle, inode, path + depth);
2770 if (err)
2771 goto out;
2772
2773 if (split == ee_block) {
2774 /*
2775 * case b: block @split is the block that the extent begins with
2776 * then we just change the state of the extent, and splitting
2777 * is not needed.
2778 */
2779 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2780 ext4_ext_mark_uninitialized(ex);
2781 else
2782 ext4_ext_mark_initialized(ex);
2783
2784 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
2785 ext4_ext_try_to_merge(inode, path, ex);
2786
2787 err = ext4_ext_dirty(handle, inode, path + depth);
2788 goto out;
2789 }
2790
2791 /* case a */
2792 memcpy(&orig_ex, ex, sizeof(orig_ex));
2793 ex->ee_len = cpu_to_le16(split - ee_block);
2794 if (split_flag & EXT4_EXT_MARK_UNINIT1)
2795 ext4_ext_mark_uninitialized(ex);
2796
2797 /*
2798 * path may lead to new leaf, not to original leaf any more
2799 * after ext4_ext_insert_extent() returns,
2800 */
2801 err = ext4_ext_dirty(handle, inode, path + depth);
2802 if (err)
2803 goto fix_extent_len;
2804
2805 ex2 = &newex;
2806 ex2->ee_block = cpu_to_le32(split);
2807 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
2808 ext4_ext_store_pblock(ex2, newblock);
2809 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2810 ext4_ext_mark_uninitialized(ex2);
2811
2812 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2813 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2814 err = ext4_ext_zeroout(inode, &orig_ex);
2815 if (err)
2816 goto fix_extent_len;
2817 /* update the extent length and mark as initialized */
2818 ex->ee_len = cpu_to_le32(ee_len);
2819 ext4_ext_try_to_merge(inode, path, ex);
2820 err = ext4_ext_dirty(handle, inode, path + depth);
2821 goto out;
2822 } else if (err)
2823 goto fix_extent_len;
2824
2825out:
2826 ext4_ext_show_leaf(inode, path);
2827 return err;
2828
2829fix_extent_len:
2830 ex->ee_len = orig_ex.ee_len;
2831 ext4_ext_dirty(handle, inode, path + depth);
2832 return err;
2833}
2834
2835/*
2836 * ext4_split_extents() splits an extent and mark extent which is covered
2837 * by @map as split_flags indicates
2838 *
2839 * It may result in splitting the extent into multiple extents (upto three)
2840 * There are three possibilities:
2841 * a> There is no split required
2842 * b> Splits in two extents: Split is happening at either end of the extent
2843 * c> Splits in three extents: Somone is splitting in middle of the extent
2844 *
2845 */
2846static int ext4_split_extent(handle_t *handle,
2847 struct inode *inode,
2848 struct ext4_ext_path *path,
2849 struct ext4_map_blocks *map,
2850 int split_flag,
2851 int flags)
2852{
2853 ext4_lblk_t ee_block;
2854 struct ext4_extent *ex;
2855 unsigned int ee_len, depth;
2856 int err = 0;
2857 int uninitialized;
2858 int split_flag1, flags1;
2859
2860 depth = ext_depth(inode);
2861 ex = path[depth].p_ext;
2862 ee_block = le32_to_cpu(ex->ee_block);
2863 ee_len = ext4_ext_get_actual_len(ex);
2864 uninitialized = ext4_ext_is_uninitialized(ex);
2865
2866 if (map->m_lblk + map->m_len < ee_block + ee_len) {
2867 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2868 EXT4_EXT_MAY_ZEROOUT : 0;
2869 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
2870 if (uninitialized)
2871 split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
2872 EXT4_EXT_MARK_UNINIT2;
2873 err = ext4_split_extent_at(handle, inode, path,
2874 map->m_lblk + map->m_len, split_flag1, flags1);
2875 if (err)
2876 goto out;
2877 }
2878
2879 ext4_ext_drop_refs(path);
2880 path = ext4_ext_find_extent(inode, map->m_lblk, path);
2881 if (IS_ERR(path))
2882 return PTR_ERR(path);
2883
2884 if (map->m_lblk >= ee_block) {
2885 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2886 EXT4_EXT_MAY_ZEROOUT : 0;
2887 if (uninitialized)
2888 split_flag1 |= EXT4_EXT_MARK_UNINIT1;
2889 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2890 split_flag1 |= EXT4_EXT_MARK_UNINIT2;
2891 err = ext4_split_extent_at(handle, inode, path,
2892 map->m_lblk, split_flag1, flags);
2893 if (err)
2894 goto out;
2895 }
2896
2897 ext4_ext_show_leaf(inode, path);
2898out:
2899 return err ? err : map->m_len;
2900}
2901
2902#define EXT4_EXT_ZERO_LEN 7
2903/*
2904 * This function is called by ext4_ext_map_blocks() if someone tries to write
2905 * to an uninitialized extent. It may result in splitting the uninitialized
2906 * extent into multiple extents (up to three - one initialized and two
2907 * uninitialized).
2908 * There are three possibilities:
2909 * a> There is no split required: Entire extent should be initialized
2910 * b> Splits in two extents: Write is happening at either end of the extent
2911 * c> Splits in three extents: Somone is writing in middle of the extent
2912 */
2913static int ext4_ext_convert_to_initialized(handle_t *handle,
2914 struct inode *inode,
2915 struct ext4_map_blocks *map,
2916 struct ext4_ext_path *path)
2917{
2918 struct ext4_map_blocks split_map;
2919 struct ext4_extent zero_ex;
2920 struct ext4_extent *ex;
2921 ext4_lblk_t ee_block, eof_block;
2922 unsigned int allocated, ee_len, depth;
2923 int err = 0;
2924 int split_flag = 0;
2925
2926 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
2927 "block %llu, max_blocks %u\n", inode->i_ino,
2928 (unsigned long long)map->m_lblk, map->m_len);
2929
2930 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
2931 inode->i_sb->s_blocksize_bits;
2932 if (eof_block < map->m_lblk + map->m_len)
2933 eof_block = map->m_lblk + map->m_len;
2934
2935 depth = ext_depth(inode);
2936 ex = path[depth].p_ext;
2937 ee_block = le32_to_cpu(ex->ee_block);
2938 ee_len = ext4_ext_get_actual_len(ex);
2939 allocated = ee_len - (map->m_lblk - ee_block);
2940
2941 WARN_ON(map->m_lblk < ee_block);
2942 /*
2943 * It is safe to convert extent to initialized via explicit
2944 * zeroout only if extent is fully insde i_size or new_size.
2945 */
2946 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
2947
2948 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
2949 if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
2950 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2951 err = ext4_ext_zeroout(inode, ex);
2952 if (err)
2953 goto out;
2954
2955 err = ext4_ext_get_access(handle, inode, path + depth);
2956 if (err)
2957 goto out;
2958 ext4_ext_mark_initialized(ex);
2959 ext4_ext_try_to_merge(inode, path, ex);
2960 err = ext4_ext_dirty(handle, inode, path + depth);
2961 goto out;
2962 }
2963
2964 /*
2965 * four cases:
2966 * 1. split the extent into three extents.
2967 * 2. split the extent into two extents, zeroout the first half.
2968 * 3. split the extent into two extents, zeroout the second half.
2969 * 4. split the extent into two extents with out zeroout.
2970 */
2971 split_map.m_lblk = map->m_lblk;
2972 split_map.m_len = map->m_len;
2973
2974 if (allocated > map->m_len) {
2975 if (allocated <= EXT4_EXT_ZERO_LEN &&
2976 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2977 /* case 3 */
2978 zero_ex.ee_block =
2979 cpu_to_le32(map->m_lblk);
2980 zero_ex.ee_len = cpu_to_le16(allocated);
2981 ext4_ext_store_pblock(&zero_ex,
2982 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
2983 err = ext4_ext_zeroout(inode, &zero_ex);
2984 if (err)
2985 goto out;
2986 split_map.m_lblk = map->m_lblk;
2987 split_map.m_len = allocated;
2988 } else if ((map->m_lblk - ee_block + map->m_len <
2989 EXT4_EXT_ZERO_LEN) &&
2990 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2991 /* case 2 */
2992 if (map->m_lblk != ee_block) {
2993 zero_ex.ee_block = ex->ee_block;
2994 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
2995 ee_block);
2996 ext4_ext_store_pblock(&zero_ex,
2997 ext4_ext_pblock(ex));
2998 err = ext4_ext_zeroout(inode, &zero_ex);
2999 if (err)
3000 goto out;
3001 }
3002
3003 split_map.m_lblk = ee_block;
3004 split_map.m_len = map->m_lblk - ee_block + map->m_len;
3005 allocated = map->m_len;
3006 }
3007 }
3008
3009 allocated = ext4_split_extent(handle, inode, path,
3010 &split_map, split_flag, 0);
3011 if (allocated < 0)
3012 err = allocated;
3013
3014out:
3015 return err ? err : allocated;
3016}
3017
3018/*
3019 * This function is called by ext4_ext_map_blocks() from
3020 * ext4_get_blocks_dio_write() when DIO to write
3021 * to an uninitialized extent.
3022 *
3023 * Writing to an uninitialized extent may result in splitting the uninitialized
3024 * extent into multiple /initialized uninitialized extents (up to three)
3025 * There are three possibilities:
3026 * a> There is no split required: Entire extent should be uninitialized
3027 * b> Splits in two extents: Write is happening at either end of the extent
3028 * c> Splits in three extents: Somone is writing in middle of the extent
3029 *
3030 * One of more index blocks maybe needed if the extent tree grow after
3031 * the uninitialized extent split. To prevent ENOSPC occur at the IO
3032 * complete, we need to split the uninitialized extent before DIO submit
3033 * the IO. The uninitialized extent called at this time will be split
3034 * into three uninitialized extent(at most). After IO complete, the part
3035 * being filled will be convert to initialized by the end_io callback function
3036 * via ext4_convert_unwritten_extents().
3037 *
3038 * Returns the size of uninitialized extent to be written on success.
3039 */
3040static int ext4_split_unwritten_extents(handle_t *handle,
3041 struct inode *inode,
3042 struct ext4_map_blocks *map,
3043 struct ext4_ext_path *path,
3044 int flags)
3045{
3046 ext4_lblk_t eof_block;
3047 ext4_lblk_t ee_block;
3048 struct ext4_extent *ex;
3049 unsigned int ee_len;
3050 int split_flag = 0, depth;
3051
3052 ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3053 "block %llu, max_blocks %u\n", inode->i_ino,
3054 (unsigned long long)map->m_lblk, map->m_len);
3055
3056 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3057 inode->i_sb->s_blocksize_bits;
3058 if (eof_block < map->m_lblk + map->m_len)
3059 eof_block = map->m_lblk + map->m_len;
3060 /*
3061 * It is safe to convert extent to initialized via explicit
3062 * zeroout only if extent is fully insde i_size or new_size.
3063 */
3064 depth = ext_depth(inode);
3065 ex = path[depth].p_ext;
3066 ee_block = le32_to_cpu(ex->ee_block);
3067 ee_len = ext4_ext_get_actual_len(ex);
3068
3069 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3070 split_flag |= EXT4_EXT_MARK_UNINIT2;
3071
3072 flags |= EXT4_GET_BLOCKS_PRE_IO;
3073 return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3074}
3075
3076static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3077 struct inode *inode,
3078 struct ext4_ext_path *path)
3079{
3080 struct ext4_extent *ex;
3081 int depth;
3082 int err = 0;
3083
3084 depth = ext_depth(inode);
3085 ex = path[depth].p_ext;
3086
3087 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3088 "block %llu, max_blocks %u\n", inode->i_ino,
3089 (unsigned long long)le32_to_cpu(ex->ee_block),
3090 ext4_ext_get_actual_len(ex));
3091
3092 err = ext4_ext_get_access(handle, inode, path + depth);
3093 if (err)
3094 goto out;
3095 /* first mark the extent as initialized */
3096 ext4_ext_mark_initialized(ex);
3097
3098 /* note: ext4_ext_correct_indexes() isn't needed here because
3099 * borders are not changed
3100 */
3101 ext4_ext_try_to_merge(inode, path, ex);
3102
3103 /* Mark modified extent as dirty */
3104 err = ext4_ext_dirty(handle, inode, path + depth);
3105out:
3106 ext4_ext_show_leaf(inode, path);
3107 return err;
3108}
3109
3110static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3111 sector_t block, int count)
3112{
3113 int i;
3114 for (i = 0; i < count; i++)
3115 unmap_underlying_metadata(bdev, block + i);
3116}
3117
3118/*
3119 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3120 */
3121static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3122 ext4_lblk_t lblk,
3123 struct ext4_ext_path *path,
3124 unsigned int len)
3125{
3126 int i, depth;
3127 struct ext4_extent_header *eh;
3128 struct ext4_extent *last_ex;
3129
3130 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3131 return 0;
3132
3133 depth = ext_depth(inode);
3134 eh = path[depth].p_hdr;
3135
3136 if (unlikely(!eh->eh_entries)) {
3137 EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
3138 "EOFBLOCKS_FL set");
3139 return -EIO;
3140 }
3141 last_ex = EXT_LAST_EXTENT(eh);
3142 /*
3143 * We should clear the EOFBLOCKS_FL flag if we are writing the
3144 * last block in the last extent in the file. We test this by
3145 * first checking to see if the caller to
3146 * ext4_ext_get_blocks() was interested in the last block (or
3147 * a block beyond the last block) in the current extent. If
3148 * this turns out to be false, we can bail out from this
3149 * function immediately.
3150 */
3151 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3152 ext4_ext_get_actual_len(last_ex))
3153 return 0;
3154 /*
3155 * If the caller does appear to be planning to write at or
3156 * beyond the end of the current extent, we then test to see
3157 * if the current extent is the last extent in the file, by
3158 * checking to make sure it was reached via the rightmost node
3159 * at each level of the tree.
3160 */
3161 for (i = depth-1; i >= 0; i--)
3162 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3163 return 0;
3164 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3165 return ext4_mark_inode_dirty(handle, inode);
3166}
3167
3168static int
3169ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3170 struct ext4_map_blocks *map,
3171 struct ext4_ext_path *path, int flags,
3172 unsigned int allocated, ext4_fsblk_t newblock)
3173{
3174 int ret = 0;
3175 int err = 0;
3176 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3177
3178 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
3179 "block %llu, max_blocks %u, flags %d, allocated %u",
3180 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3181 flags, allocated);
3182 ext4_ext_show_leaf(inode, path);
3183
3184 /* get_block() before submit the IO, split the extent */
3185 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3186 ret = ext4_split_unwritten_extents(handle, inode, map,
3187 path, flags);
3188 /*
3189 * Flag the inode(non aio case) or end_io struct (aio case)
3190 * that this IO needs to conversion to written when IO is
3191 * completed
3192 */
3193 if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3194 io->flag = EXT4_IO_END_UNWRITTEN;
3195 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3196 } else
3197 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3198 if (ext4_should_dioread_nolock(inode))
3199 map->m_flags |= EXT4_MAP_UNINIT;
3200 goto out;
3201 }
3202 /* IO end_io complete, convert the filled extent to written */
3203 if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3204 ret = ext4_convert_unwritten_extents_endio(handle, inode,
3205 path);
3206 if (ret >= 0) {
3207 ext4_update_inode_fsync_trans(handle, inode, 1);
3208 err = check_eofblocks_fl(handle, inode, map->m_lblk,
3209 path, map->m_len);
3210 } else
3211 err = ret;
3212 goto out2;
3213 }
3214 /* buffered IO case */
3215 /*
3216 * repeat fallocate creation request
3217 * we already have an unwritten extent
3218 */
3219 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
3220 goto map_out;
3221
3222 /* buffered READ or buffered write_begin() lookup */
3223 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3224 /*
3225 * We have blocks reserved already. We
3226 * return allocated blocks so that delalloc
3227 * won't do block reservation for us. But
3228 * the buffer head will be unmapped so that
3229 * a read from the block returns 0s.
3230 */
3231 map->m_flags |= EXT4_MAP_UNWRITTEN;
3232 goto out1;
3233 }
3234
3235 /* buffered write, writepage time, convert*/
3236 ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
3237 if (ret >= 0) {
3238 ext4_update_inode_fsync_trans(handle, inode, 1);
3239 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3240 map->m_len);
3241 if (err < 0)
3242 goto out2;
3243 }
3244
3245out:
3246 if (ret <= 0) {
3247 err = ret;
3248 goto out2;
3249 } else
3250 allocated = ret;
3251 map->m_flags |= EXT4_MAP_NEW;
3252 /*
3253 * if we allocated more blocks than requested
3254 * we need to make sure we unmap the extra block
3255 * allocated. The actual needed block will get
3256 * unmapped later when we find the buffer_head marked
3257 * new.
3258 */
3259 if (allocated > map->m_len) {
3260 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3261 newblock + map->m_len,
3262 allocated - map->m_len);
3263 allocated = map->m_len;
3264 }
3265
3266 /*
3267 * If we have done fallocate with the offset that is already
3268 * delayed allocated, we would have block reservation
3269 * and quota reservation done in the delayed write path.
3270 * But fallocate would have already updated quota and block
3271 * count for this offset. So cancel these reservation
3272 */
3273 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3274 ext4_da_update_reserve_space(inode, allocated, 0);
3275
3276map_out:
3277 map->m_flags |= EXT4_MAP_MAPPED;
3278out1:
3279 if (allocated > map->m_len)
3280 allocated = map->m_len;
3281 ext4_ext_show_leaf(inode, path);
3282 map->m_pblk = newblock;
3283 map->m_len = allocated;
3284out2:
3285 if (path) {
3286 ext4_ext_drop_refs(path);
3287 kfree(path);
3288 }
3289 return err ? err : allocated;
3290}
3291
3292/*
3293 * Block allocation/map/preallocation routine for extents based files
3294 *
3295 *
3296 * Need to be called with
3297 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3298 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3299 *
3300 * return > 0, number of of blocks already mapped/allocated
3301 * if create == 0 and these are pre-allocated blocks
3302 * buffer head is unmapped
3303 * otherwise blocks are mapped
3304 *
3305 * return = 0, if plain look up failed (blocks have not been allocated)
3306 * buffer head is unmapped
3307 *
3308 * return < 0, error case.
3309 */
3310int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
3311 struct ext4_map_blocks *map, int flags)
3312{
3313 struct ext4_ext_path *path = NULL;
3314 struct ext4_extent newex, *ex;
3315 ext4_fsblk_t newblock = 0;
3316 int err = 0, depth, ret;
3317 unsigned int allocated = 0;
3318 unsigned int punched_out = 0;
3319 unsigned int result = 0;
3320 struct ext4_allocation_request ar;
3321 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3322 struct ext4_map_blocks punch_map;
3323
3324 ext_debug("blocks %u/%u requested for inode %lu\n",
3325 map->m_lblk, map->m_len, inode->i_ino);
3326 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
3327
3328 /* check in cache */
3329 if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) &&
3330 ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
3331 if (!newex.ee_start_lo && !newex.ee_start_hi) {
3332 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3333 /*
3334 * block isn't allocated yet and
3335 * user doesn't want to allocate it
3336 */
3337 goto out2;
3338 }
3339 /* we should allocate requested block */
3340 } else {
3341 /* block is already allocated */
3342 newblock = map->m_lblk
3343 - le32_to_cpu(newex.ee_block)
3344 + ext4_ext_pblock(&newex);
3345 /* number of remaining blocks in the extent */
3346 allocated = ext4_ext_get_actual_len(&newex) -
3347 (map->m_lblk - le32_to_cpu(newex.ee_block));
3348 goto out;
3349 }
3350 }
3351
3352 /* find extent for this block */
3353 path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
3354 if (IS_ERR(path)) {
3355 err = PTR_ERR(path);
3356 path = NULL;
3357 goto out2;
3358 }
3359
3360 depth = ext_depth(inode);
3361
3362 /*
3363 * consistent leaf must not be empty;
3364 * this situation is possible, though, _during_ tree modification;
3365 * this is why assert can't be put in ext4_ext_find_extent()
3366 */
3367 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
3368 EXT4_ERROR_INODE(inode, "bad extent address "
3369 "lblock: %lu, depth: %d pblock %lld",
3370 (unsigned long) map->m_lblk, depth,
3371 path[depth].p_block);
3372 err = -EIO;
3373 goto out2;
3374 }
3375
3376 ex = path[depth].p_ext;
3377 if (ex) {
3378 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3379 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3380 unsigned short ee_len;
3381
3382 /*
3383 * Uninitialized extents are treated as holes, except that
3384 * we split out initialized portions during a write.
3385 */
3386 ee_len = ext4_ext_get_actual_len(ex);
3387 /* if found extent covers block, simply return it */
3388 if (in_range(map->m_lblk, ee_block, ee_len)) {
3389 newblock = map->m_lblk - ee_block + ee_start;
3390 /* number of remaining blocks in the extent */
3391 allocated = ee_len - (map->m_lblk - ee_block);
3392 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
3393 ee_block, ee_len, newblock);
3394
3395 if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
3396 /*
3397 * Do not put uninitialized extent
3398 * in the cache
3399 */
3400 if (!ext4_ext_is_uninitialized(ex)) {
3401 ext4_ext_put_in_cache(inode, ee_block,
3402 ee_len, ee_start);
3403 goto out;
3404 }
3405 ret = ext4_ext_handle_uninitialized_extents(
3406 handle, inode, map, path, flags,
3407 allocated, newblock);
3408 return ret;
3409 }
3410
3411 /*
3412 * Punch out the map length, but only to the
3413 * end of the extent
3414 */
3415 punched_out = allocated < map->m_len ?
3416 allocated : map->m_len;
3417
3418 /*
3419 * Sense extents need to be converted to
3420 * uninitialized, they must fit in an
3421 * uninitialized extent
3422 */
3423 if (punched_out > EXT_UNINIT_MAX_LEN)
3424 punched_out = EXT_UNINIT_MAX_LEN;
3425
3426 punch_map.m_lblk = map->m_lblk;
3427 punch_map.m_pblk = newblock;
3428 punch_map.m_len = punched_out;
3429 punch_map.m_flags = 0;
3430
3431 /* Check to see if the extent needs to be split */
3432 if (punch_map.m_len != ee_len ||
3433 punch_map.m_lblk != ee_block) {
3434
3435 ret = ext4_split_extent(handle, inode,
3436 path, &punch_map, 0,
3437 EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
3438 EXT4_GET_BLOCKS_PRE_IO);
3439
3440 if (ret < 0) {
3441 err = ret;
3442 goto out2;
3443 }
3444 /*
3445 * find extent for the block at
3446 * the start of the hole
3447 */
3448 ext4_ext_drop_refs(path);
3449 kfree(path);
3450
3451 path = ext4_ext_find_extent(inode,
3452 map->m_lblk, NULL);
3453 if (IS_ERR(path)) {
3454 err = PTR_ERR(path);
3455 path = NULL;
3456 goto out2;
3457 }
3458
3459 depth = ext_depth(inode);
3460 ex = path[depth].p_ext;
3461 ee_len = ext4_ext_get_actual_len(ex);
3462 ee_block = le32_to_cpu(ex->ee_block);
3463 ee_start = ext4_ext_pblock(ex);
3464
3465 }
3466
3467 ext4_ext_mark_uninitialized(ex);
3468
3469 ext4_ext_invalidate_cache(inode);
3470
3471 err = ext4_ext_rm_leaf(handle, inode, path,
3472 map->m_lblk, map->m_lblk + punched_out);
3473
3474 if (!err && path->p_hdr->eh_entries == 0) {
3475 /*
3476 * Punch hole freed all of this sub tree,
3477 * so we need to correct eh_depth
3478 */
3479 err = ext4_ext_get_access(handle, inode, path);
3480 if (err == 0) {
3481 ext_inode_hdr(inode)->eh_depth = 0;
3482 ext_inode_hdr(inode)->eh_max =
3483 cpu_to_le16(ext4_ext_space_root(
3484 inode, 0));
3485
3486 err = ext4_ext_dirty(
3487 handle, inode, path);
3488 }
3489 }
3490
3491 goto out2;
3492 }
3493 }
3494
3495 /*
3496 * requested block isn't allocated yet;
3497 * we couldn't try to create block if create flag is zero
3498 */
3499 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3500 /*
3501 * put just found gap into cache to speed up
3502 * subsequent requests
3503 */
3504 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
3505 goto out2;
3506 }
3507 /*
3508 * Okay, we need to do block allocation.
3509 */
3510
3511 /* find neighbour allocated blocks */
3512 ar.lleft = map->m_lblk;
3513 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3514 if (err)
3515 goto out2;
3516 ar.lright = map->m_lblk;
3517 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
3518 if (err)
3519 goto out2;
3520
3521 /*
3522 * See if request is beyond maximum number of blocks we can have in
3523 * a single extent. For an initialized extent this limit is
3524 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
3525 * EXT_UNINIT_MAX_LEN.
3526 */
3527 if (map->m_len > EXT_INIT_MAX_LEN &&
3528 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3529 map->m_len = EXT_INIT_MAX_LEN;
3530 else if (map->m_len > EXT_UNINIT_MAX_LEN &&
3531 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3532 map->m_len = EXT_UNINIT_MAX_LEN;
3533
3534 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
3535 newex.ee_block = cpu_to_le32(map->m_lblk);
3536 newex.ee_len = cpu_to_le16(map->m_len);
3537 err = ext4_ext_check_overlap(inode, &newex, path);
3538 if (err)
3539 allocated = ext4_ext_get_actual_len(&newex);
3540 else
3541 allocated = map->m_len;
3542
3543 /* allocate new block */
3544 ar.inode = inode;
3545 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
3546 ar.logical = map->m_lblk;
3547 ar.len = allocated;
3548 if (S_ISREG(inode->i_mode))
3549 ar.flags = EXT4_MB_HINT_DATA;
3550 else
3551 /* disable in-core preallocation for non-regular files */
3552 ar.flags = 0;
3553 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
3554 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
3555 newblock = ext4_mb_new_blocks(handle, &ar, &err);
3556 if (!newblock)
3557 goto out2;
3558 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
3559 ar.goal, newblock, allocated);
3560
3561 /* try to insert new extent into found leaf and return */
3562 ext4_ext_store_pblock(&newex, newblock);
3563 newex.ee_len = cpu_to_le16(ar.len);
3564 /* Mark uninitialized */
3565 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
3566 ext4_ext_mark_uninitialized(&newex);
3567 /*
3568 * io_end structure was created for every IO write to an
3569 * uninitialized extent. To avoid unnecessary conversion,
3570 * here we flag the IO that really needs the conversion.
3571 * For non asycn direct IO case, flag the inode state
3572 * that we need to perform conversion when IO is done.
3573 */
3574 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3575 if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3576 io->flag = EXT4_IO_END_UNWRITTEN;
3577 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3578 } else
3579 ext4_set_inode_state(inode,
3580 EXT4_STATE_DIO_UNWRITTEN);
3581 }
3582 if (ext4_should_dioread_nolock(inode))
3583 map->m_flags |= EXT4_MAP_UNINIT;
3584 }
3585
3586 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
3587 if (!err)
3588 err = ext4_ext_insert_extent(handle, inode, path,
3589 &newex, flags);
3590 if (err) {
3591 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
3592 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
3593 /* free data blocks we just allocated */
3594 /* not a good idea to call discard here directly,
3595 * but otherwise we'd need to call it every free() */
3596 ext4_discard_preallocations(inode);
3597 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
3598 ext4_ext_get_actual_len(&newex), fb_flags);
3599 goto out2;
3600 }
3601
3602 /* previous routine could use block we allocated */
3603 newblock = ext4_ext_pblock(&newex);
3604 allocated = ext4_ext_get_actual_len(&newex);
3605 if (allocated > map->m_len)
3606 allocated = map->m_len;
3607 map->m_flags |= EXT4_MAP_NEW;
3608
3609 /*
3610 * Update reserved blocks/metadata blocks after successful
3611 * block allocation which had been deferred till now.
3612 */
3613 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3614 ext4_da_update_reserve_space(inode, allocated, 1);
3615
3616 /*
3617 * Cache the extent and update transaction to commit on fdatasync only
3618 * when it is _not_ an uninitialized extent.
3619 */
3620 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
3621 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
3622 ext4_update_inode_fsync_trans(handle, inode, 1);
3623 } else
3624 ext4_update_inode_fsync_trans(handle, inode, 0);
3625out:
3626 if (allocated > map->m_len)
3627 allocated = map->m_len;
3628 ext4_ext_show_leaf(inode, path);
3629 map->m_flags |= EXT4_MAP_MAPPED;
3630 map->m_pblk = newblock;
3631 map->m_len = allocated;
3632out2:
3633 if (path) {
3634 ext4_ext_drop_refs(path);
3635 kfree(path);
3636 }
3637 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
3638 newblock, map->m_len, err ? err : allocated);
3639
3640 result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
3641 punched_out : allocated;
3642
3643 return err ? err : result;
3644}
3645
3646void ext4_ext_truncate(struct inode *inode)
3647{
3648 struct address_space *mapping = inode->i_mapping;
3649 struct super_block *sb = inode->i_sb;
3650 ext4_lblk_t last_block;
3651 handle_t *handle;
3652 int err = 0;
3653
3654 /*
3655 * finish any pending end_io work so we won't run the risk of
3656 * converting any truncated blocks to initialized later
3657 */
3658 ext4_flush_completed_IO(inode);
3659
3660 /*
3661 * probably first extent we're gonna free will be last in block
3662 */
3663 err = ext4_writepage_trans_blocks(inode);
3664 handle = ext4_journal_start(inode, err);
3665 if (IS_ERR(handle))
3666 return;
3667
3668 if (inode->i_size & (sb->s_blocksize - 1))
3669 ext4_block_truncate_page(handle, mapping, inode->i_size);
3670
3671 if (ext4_orphan_add(handle, inode))
3672 goto out_stop;
3673
3674 down_write(&EXT4_I(inode)->i_data_sem);
3675 ext4_ext_invalidate_cache(inode);
3676
3677 ext4_discard_preallocations(inode);
3678
3679 /*
3680 * TODO: optimization is possible here.
3681 * Probably we need not scan at all,
3682 * because page truncation is enough.
3683 */
3684
3685 /* we have to know where to truncate from in crash case */
3686 EXT4_I(inode)->i_disksize = inode->i_size;
3687 ext4_mark_inode_dirty(handle, inode);
3688
3689 last_block = (inode->i_size + sb->s_blocksize - 1)
3690 >> EXT4_BLOCK_SIZE_BITS(sb);
3691 err = ext4_ext_remove_space(inode, last_block);
3692
3693 /* In a multi-transaction truncate, we only make the final
3694 * transaction synchronous.
3695 */
3696 if (IS_SYNC(inode))
3697 ext4_handle_sync(handle);
3698
3699 up_write(&EXT4_I(inode)->i_data_sem);
3700
3701out_stop:
3702 /*
3703 * If this was a simple ftruncate() and the file will remain alive,
3704 * then we need to clear up the orphan record which we created above.
3705 * However, if this was a real unlink then we were called by
3706 * ext4_delete_inode(), and we allow that function to clean up the
3707 * orphan info for us.
3708 */
3709 if (inode->i_nlink)
3710 ext4_orphan_del(handle, inode);
3711
3712 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3713 ext4_mark_inode_dirty(handle, inode);
3714 ext4_journal_stop(handle);
3715}
3716
3717static void ext4_falloc_update_inode(struct inode *inode,
3718 int mode, loff_t new_size, int update_ctime)
3719{
3720 struct timespec now;
3721
3722 if (update_ctime) {
3723 now = current_fs_time(inode->i_sb);
3724 if (!timespec_equal(&inode->i_ctime, &now))
3725 inode->i_ctime = now;
3726 }
3727 /*
3728 * Update only when preallocation was requested beyond
3729 * the file size.
3730 */
3731 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3732 if (new_size > i_size_read(inode))
3733 i_size_write(inode, new_size);
3734 if (new_size > EXT4_I(inode)->i_disksize)
3735 ext4_update_i_disksize(inode, new_size);
3736 } else {
3737 /*
3738 * Mark that we allocate beyond EOF so the subsequent truncate
3739 * can proceed even if the new size is the same as i_size.
3740 */
3741 if (new_size > i_size_read(inode))
3742 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3743 }
3744
3745}
3746
3747/*
3748 * preallocate space for a file. This implements ext4's fallocate file
3749 * operation, which gets called from sys_fallocate system call.
3750 * For block-mapped files, posix_fallocate should fall back to the method
3751 * of writing zeroes to the required new blocks (the same behavior which is
3752 * expected for file systems which do not support fallocate() system call).
3753 */
3754long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
3755{
3756 struct inode *inode = file->f_path.dentry->d_inode;
3757 handle_t *handle;
3758 loff_t new_size;
3759 unsigned int max_blocks;
3760 int ret = 0;
3761 int ret2 = 0;
3762 int retries = 0;
3763 struct ext4_map_blocks map;
3764 unsigned int credits, blkbits = inode->i_blkbits;
3765
3766 /*
3767 * currently supporting (pre)allocate mode for extent-based
3768 * files _only_
3769 */
3770 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
3771 return -EOPNOTSUPP;
3772
3773 /* Return error if mode is not supported */
3774 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
3775 return -EOPNOTSUPP;
3776
3777 if (mode & FALLOC_FL_PUNCH_HOLE)
3778 return ext4_punch_hole(file, offset, len);
3779
3780 trace_ext4_fallocate_enter(inode, offset, len, mode);
3781 map.m_lblk = offset >> blkbits;
3782 /*
3783 * We can't just convert len to max_blocks because
3784 * If blocksize = 4096 offset = 3072 and len = 2048
3785 */
3786 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3787 - map.m_lblk;
3788 /*
3789 * credits to insert 1 extent into extent tree
3790 */
3791 credits = ext4_chunk_trans_blocks(inode, max_blocks);
3792 mutex_lock(&inode->i_mutex);
3793 ret = inode_newsize_ok(inode, (len + offset));
3794 if (ret) {
3795 mutex_unlock(&inode->i_mutex);
3796 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
3797 return ret;
3798 }
3799retry:
3800 while (ret >= 0 && ret < max_blocks) {
3801 map.m_lblk = map.m_lblk + ret;
3802 map.m_len = max_blocks = max_blocks - ret;
3803 handle = ext4_journal_start(inode, credits);
3804 if (IS_ERR(handle)) {
3805 ret = PTR_ERR(handle);
3806 break;
3807 }
3808 ret = ext4_map_blocks(handle, inode, &map,
3809 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
3810 EXT4_GET_BLOCKS_NO_NORMALIZE);
3811 if (ret <= 0) {
3812#ifdef EXT4FS_DEBUG
3813 WARN_ON(ret <= 0);
3814 printk(KERN_ERR "%s: ext4_ext_map_blocks "
3815 "returned error inode#%lu, block=%u, "
3816 "max_blocks=%u", __func__,
3817 inode->i_ino, map.m_lblk, max_blocks);
3818#endif
3819 ext4_mark_inode_dirty(handle, inode);
3820 ret2 = ext4_journal_stop(handle);
3821 break;
3822 }
3823 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
3824 blkbits) >> blkbits))
3825 new_size = offset + len;
3826 else
3827 new_size = ((loff_t) map.m_lblk + ret) << blkbits;
3828
3829 ext4_falloc_update_inode(inode, mode, new_size,
3830 (map.m_flags & EXT4_MAP_NEW));
3831 ext4_mark_inode_dirty(handle, inode);
3832 ret2 = ext4_journal_stop(handle);
3833 if (ret2)
3834 break;
3835 }
3836 if (ret == -ENOSPC &&
3837 ext4_should_retry_alloc(inode->i_sb, &retries)) {
3838 ret = 0;
3839 goto retry;
3840 }
3841 mutex_unlock(&inode->i_mutex);
3842 trace_ext4_fallocate_exit(inode, offset, max_blocks,
3843 ret > 0 ? ret2 : ret);
3844 return ret > 0 ? ret2 : ret;
3845}
3846
3847/*
3848 * This function convert a range of blocks to written extents
3849 * The caller of this function will pass the start offset and the size.
3850 * all unwritten extents within this range will be converted to
3851 * written extents.
3852 *
3853 * This function is called from the direct IO end io call back
3854 * function, to convert the fallocated extents after IO is completed.
3855 * Returns 0 on success.
3856 */
3857int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
3858 ssize_t len)
3859{
3860 handle_t *handle;
3861 unsigned int max_blocks;
3862 int ret = 0;
3863 int ret2 = 0;
3864 struct ext4_map_blocks map;
3865 unsigned int credits, blkbits = inode->i_blkbits;
3866
3867 map.m_lblk = offset >> blkbits;
3868 /*
3869 * We can't just convert len to max_blocks because
3870 * If blocksize = 4096 offset = 3072 and len = 2048
3871 */
3872 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
3873 map.m_lblk);
3874 /*
3875 * credits to insert 1 extent into extent tree
3876 */
3877 credits = ext4_chunk_trans_blocks(inode, max_blocks);
3878 while (ret >= 0 && ret < max_blocks) {
3879 map.m_lblk += ret;
3880 map.m_len = (max_blocks -= ret);
3881 handle = ext4_journal_start(inode, credits);
3882 if (IS_ERR(handle)) {
3883 ret = PTR_ERR(handle);
3884 break;
3885 }
3886 ret = ext4_map_blocks(handle, inode, &map,
3887 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
3888 if (ret <= 0) {
3889 WARN_ON(ret <= 0);
3890 printk(KERN_ERR "%s: ext4_ext_map_blocks "
3891 "returned error inode#%lu, block=%u, "
3892 "max_blocks=%u", __func__,
3893 inode->i_ino, map.m_lblk, map.m_len);
3894 }
3895 ext4_mark_inode_dirty(handle, inode);
3896 ret2 = ext4_journal_stop(handle);
3897 if (ret <= 0 || ret2 )
3898 break;
3899 }
3900 return ret > 0 ? ret2 : ret;
3901}
3902
3903/*
3904 * Callback function called for each extent to gather FIEMAP information.
3905 */
3906static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next,
3907 struct ext4_ext_cache *newex, struct ext4_extent *ex,
3908 void *data)
3909{
3910 __u64 logical;
3911 __u64 physical;
3912 __u64 length;
3913 __u32 flags = 0;
3914 int ret = 0;
3915 struct fiemap_extent_info *fieinfo = data;
3916 unsigned char blksize_bits;
3917
3918 blksize_bits = inode->i_sb->s_blocksize_bits;
3919 logical = (__u64)newex->ec_block << blksize_bits;
3920
3921 if (newex->ec_start == 0) {
3922 /*
3923 * No extent in extent-tree contains block @newex->ec_start,
3924 * then the block may stay in 1)a hole or 2)delayed-extent.
3925 *
3926 * Holes or delayed-extents are processed as follows.
3927 * 1. lookup dirty pages with specified range in pagecache.
3928 * If no page is got, then there is no delayed-extent and
3929 * return with EXT_CONTINUE.
3930 * 2. find the 1st mapped buffer,
3931 * 3. check if the mapped buffer is both in the request range
3932 * and a delayed buffer. If not, there is no delayed-extent,
3933 * then return.
3934 * 4. a delayed-extent is found, the extent will be collected.
3935 */
3936 ext4_lblk_t end = 0;
3937 pgoff_t last_offset;
3938 pgoff_t offset;
3939 pgoff_t index;
3940 pgoff_t start_index = 0;
3941 struct page **pages = NULL;
3942 struct buffer_head *bh = NULL;
3943 struct buffer_head *head = NULL;
3944 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
3945
3946 pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
3947 if (pages == NULL)
3948 return -ENOMEM;
3949
3950 offset = logical >> PAGE_SHIFT;
3951repeat:
3952 last_offset = offset;
3953 head = NULL;
3954 ret = find_get_pages_tag(inode->i_mapping, &offset,
3955 PAGECACHE_TAG_DIRTY, nr_pages, pages);
3956
3957 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
3958 /* First time, try to find a mapped buffer. */
3959 if (ret == 0) {
3960out:
3961 for (index = 0; index < ret; index++)
3962 page_cache_release(pages[index]);
3963 /* just a hole. */
3964 kfree(pages);
3965 return EXT_CONTINUE;
3966 }
3967 index = 0;
3968
3969next_page:
3970 /* Try to find the 1st mapped buffer. */
3971 end = ((__u64)pages[index]->index << PAGE_SHIFT) >>
3972 blksize_bits;
3973 if (!page_has_buffers(pages[index]))
3974 goto out;
3975 head = page_buffers(pages[index]);
3976 if (!head)
3977 goto out;
3978
3979 index++;
3980 bh = head;
3981 do {
3982 if (end >= newex->ec_block +
3983 newex->ec_len)
3984 /* The buffer is out of
3985 * the request range.
3986 */
3987 goto out;
3988
3989 if (buffer_mapped(bh) &&
3990 end >= newex->ec_block) {
3991 start_index = index - 1;
3992 /* get the 1st mapped buffer. */
3993 goto found_mapped_buffer;
3994 }
3995
3996 bh = bh->b_this_page;
3997 end++;
3998 } while (bh != head);
3999
4000 /* No mapped buffer in the range found in this page,
4001 * We need to look up next page.
4002 */
4003 if (index >= ret) {
4004 /* There is no page left, but we need to limit
4005 * newex->ec_len.
4006 */
4007 newex->ec_len = end - newex->ec_block;
4008 goto out;
4009 }
4010 goto next_page;
4011 } else {
4012 /*Find contiguous delayed buffers. */
4013 if (ret > 0 && pages[0]->index == last_offset)
4014 head = page_buffers(pages[0]);
4015 bh = head;
4016 index = 1;
4017 start_index = 0;
4018 }
4019
4020found_mapped_buffer:
4021 if (bh != NULL && buffer_delay(bh)) {
4022 /* 1st or contiguous delayed buffer found. */
4023 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
4024 /*
4025 * 1st delayed buffer found, record
4026 * the start of extent.
4027 */
4028 flags |= FIEMAP_EXTENT_DELALLOC;
4029 newex->ec_block = end;
4030 logical = (__u64)end << blksize_bits;
4031 }
4032 /* Find contiguous delayed buffers. */
4033 do {
4034 if (!buffer_delay(bh))
4035 goto found_delayed_extent;
4036 bh = bh->b_this_page;
4037 end++;
4038 } while (bh != head);
4039
4040 for (; index < ret; index++) {
4041 if (!page_has_buffers(pages[index])) {
4042 bh = NULL;
4043 break;
4044 }
4045 head = page_buffers(pages[index]);
4046 if (!head) {
4047 bh = NULL;
4048 break;
4049 }
4050
4051 if (pages[index]->index !=
4052 pages[start_index]->index + index
4053 - start_index) {
4054 /* Blocks are not contiguous. */
4055 bh = NULL;
4056 break;
4057 }
4058 bh = head;
4059 do {
4060 if (!buffer_delay(bh))
4061 /* Delayed-extent ends. */
4062 goto found_delayed_extent;
4063 bh = bh->b_this_page;
4064 end++;
4065 } while (bh != head);
4066 }
4067 } else if (!(flags & FIEMAP_EXTENT_DELALLOC))
4068 /* a hole found. */
4069 goto out;
4070
4071found_delayed_extent:
4072 newex->ec_len = min(end - newex->ec_block,
4073 (ext4_lblk_t)EXT_INIT_MAX_LEN);
4074 if (ret == nr_pages && bh != NULL &&
4075 newex->ec_len < EXT_INIT_MAX_LEN &&
4076 buffer_delay(bh)) {
4077 /* Have not collected an extent and continue. */
4078 for (index = 0; index < ret; index++)
4079 page_cache_release(pages[index]);
4080 goto repeat;
4081 }
4082
4083 for (index = 0; index < ret; index++)
4084 page_cache_release(pages[index]);
4085 kfree(pages);
4086 }
4087
4088 physical = (__u64)newex->ec_start << blksize_bits;
4089 length = (__u64)newex->ec_len << blksize_bits;
4090
4091 if (ex && ext4_ext_is_uninitialized(ex))
4092 flags |= FIEMAP_EXTENT_UNWRITTEN;
4093
4094 if (next == EXT_MAX_BLOCKS)
4095 flags |= FIEMAP_EXTENT_LAST;
4096
4097 ret = fiemap_fill_next_extent(fieinfo, logical, physical,
4098 length, flags);
4099 if (ret < 0)
4100 return ret;
4101 if (ret == 1)
4102 return EXT_BREAK;
4103 return EXT_CONTINUE;
4104}
4105
4106/* fiemap flags we can handle specified here */
4107#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4108
4109static int ext4_xattr_fiemap(struct inode *inode,
4110 struct fiemap_extent_info *fieinfo)
4111{
4112 __u64 physical = 0;
4113 __u64 length;
4114 __u32 flags = FIEMAP_EXTENT_LAST;
4115 int blockbits = inode->i_sb->s_blocksize_bits;
4116 int error = 0;
4117
4118 /* in-inode? */
4119 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4120 struct ext4_iloc iloc;
4121 int offset; /* offset of xattr in inode */
4122
4123 error = ext4_get_inode_loc(inode, &iloc);
4124 if (error)
4125 return error;
4126 physical = iloc.bh->b_blocknr << blockbits;
4127 offset = EXT4_GOOD_OLD_INODE_SIZE +
4128 EXT4_I(inode)->i_extra_isize;
4129 physical += offset;
4130 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4131 flags |= FIEMAP_EXTENT_DATA_INLINE;
4132 brelse(iloc.bh);
4133 } else { /* external block */
4134 physical = EXT4_I(inode)->i_file_acl << blockbits;
4135 length = inode->i_sb->s_blocksize;
4136 }
4137
4138 if (physical)
4139 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4140 length, flags);
4141 return (error < 0 ? error : 0);
4142}
4143
4144/*
4145 * ext4_ext_punch_hole
4146 *
4147 * Punches a hole of "length" bytes in a file starting
4148 * at byte "offset"
4149 *
4150 * @inode: The inode of the file to punch a hole in
4151 * @offset: The starting byte offset of the hole
4152 * @length: The length of the hole
4153 *
4154 * Returns the number of blocks removed or negative on err
4155 */
4156int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
4157{
4158 struct inode *inode = file->f_path.dentry->d_inode;
4159 struct super_block *sb = inode->i_sb;
4160 struct ext4_ext_cache cache_ex;
4161 ext4_lblk_t first_block, last_block, num_blocks, iblock, max_blocks;
4162 struct address_space *mapping = inode->i_mapping;
4163 struct ext4_map_blocks map;
4164 handle_t *handle;
4165 loff_t first_block_offset, last_block_offset, block_len;
4166 loff_t first_page, last_page, first_page_offset, last_page_offset;
4167 int ret, credits, blocks_released, err = 0;
4168
4169 first_block = (offset + sb->s_blocksize - 1) >>
4170 EXT4_BLOCK_SIZE_BITS(sb);
4171 last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4172
4173 first_block_offset = first_block << EXT4_BLOCK_SIZE_BITS(sb);
4174 last_block_offset = last_block << EXT4_BLOCK_SIZE_BITS(sb);
4175
4176 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
4177 last_page = (offset + length) >> PAGE_CACHE_SHIFT;
4178
4179 first_page_offset = first_page << PAGE_CACHE_SHIFT;
4180 last_page_offset = last_page << PAGE_CACHE_SHIFT;
4181
4182 /*
4183 * Write out all dirty pages to avoid race conditions
4184 * Then release them.
4185 */
4186 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4187 err = filemap_write_and_wait_range(mapping,
4188 first_page_offset == 0 ? 0 : first_page_offset-1,
4189 last_page_offset);
4190
4191 if (err)
4192 return err;
4193 }
4194
4195 /* Now release the pages */
4196 if (last_page_offset > first_page_offset) {
4197 truncate_inode_pages_range(mapping, first_page_offset,
4198 last_page_offset-1);
4199 }
4200
4201 /* finish any pending end_io work */
4202 ext4_flush_completed_IO(inode);
4203
4204 credits = ext4_writepage_trans_blocks(inode);
4205 handle = ext4_journal_start(inode, credits);
4206 if (IS_ERR(handle))
4207 return PTR_ERR(handle);
4208
4209 err = ext4_orphan_add(handle, inode);
4210 if (err)
4211 goto out;
4212
4213 /*
4214 * Now we need to zero out the un block aligned data.
4215 * If the file is smaller than a block, just
4216 * zero out the middle
4217 */
4218 if (first_block > last_block)
4219 ext4_block_zero_page_range(handle, mapping, offset, length);
4220 else {
4221 /* zero out the head of the hole before the first block */
4222 block_len = first_block_offset - offset;
4223 if (block_len > 0)
4224 ext4_block_zero_page_range(handle, mapping,
4225 offset, block_len);
4226
4227 /* zero out the tail of the hole after the last block */
4228 block_len = offset + length - last_block_offset;
4229 if (block_len > 0) {
4230 ext4_block_zero_page_range(handle, mapping,
4231 last_block_offset, block_len);
4232 }
4233 }
4234
4235 /* If there are no blocks to remove, return now */
4236 if (first_block >= last_block)
4237 goto out;
4238
4239 down_write(&EXT4_I(inode)->i_data_sem);
4240 ext4_ext_invalidate_cache(inode);
4241 ext4_discard_preallocations(inode);
4242
4243 /*
4244 * Loop over all the blocks and identify blocks
4245 * that need to be punched out
4246 */
4247 iblock = first_block;
4248 blocks_released = 0;
4249 while (iblock < last_block) {
4250 max_blocks = last_block - iblock;
4251 num_blocks = 1;
4252 memset(&map, 0, sizeof(map));
4253 map.m_lblk = iblock;
4254 map.m_len = max_blocks;
4255 ret = ext4_ext_map_blocks(handle, inode, &map,
4256 EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
4257
4258 if (ret > 0) {
4259 blocks_released += ret;
4260 num_blocks = ret;
4261 } else if (ret == 0) {
4262 /*
4263 * If map blocks could not find the block,
4264 * then it is in a hole. If the hole was
4265 * not already cached, then map blocks should
4266 * put it in the cache. So we can get the hole
4267 * out of the cache
4268 */
4269 memset(&cache_ex, 0, sizeof(cache_ex));
4270 if ((ext4_ext_check_cache(inode, iblock, &cache_ex)) &&
4271 !cache_ex.ec_start) {
4272
4273 /* The hole is cached */
4274 num_blocks = cache_ex.ec_block +
4275 cache_ex.ec_len - iblock;
4276
4277 } else {
4278 /* The block could not be identified */
4279 err = -EIO;
4280 break;
4281 }
4282 } else {
4283 /* Map blocks error */
4284 err = ret;
4285 break;
4286 }
4287
4288 if (num_blocks == 0) {
4289 /* This condition should never happen */
4290 ext_debug("Block lookup failed");
4291 err = -EIO;
4292 break;
4293 }
4294
4295 iblock += num_blocks;
4296 }
4297
4298 if (blocks_released > 0) {
4299 ext4_ext_invalidate_cache(inode);
4300 ext4_discard_preallocations(inode);
4301 }
4302
4303 if (IS_SYNC(inode))
4304 ext4_handle_sync(handle);
4305
4306 up_write(&EXT4_I(inode)->i_data_sem);
4307
4308out:
4309 ext4_orphan_del(handle, inode);
4310 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4311 ext4_mark_inode_dirty(handle, inode);
4312 ext4_journal_stop(handle);
4313 return err;
4314}
4315int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4316 __u64 start, __u64 len)
4317{
4318 ext4_lblk_t start_blk;
4319 int error = 0;
4320
4321 /* fallback to generic here if not in extents fmt */
4322 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4323 return generic_block_fiemap(inode, fieinfo, start, len,
4324 ext4_get_block);
4325
4326 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4327 return -EBADR;
4328
4329 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4330 error = ext4_xattr_fiemap(inode, fieinfo);
4331 } else {
4332 ext4_lblk_t len_blks;
4333 __u64 last_blk;
4334
4335 start_blk = start >> inode->i_sb->s_blocksize_bits;
4336 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4337 if (last_blk >= EXT_MAX_BLOCKS)
4338 last_blk = EXT_MAX_BLOCKS-1;
4339 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4340
4341 /*
4342 * Walk the extent tree gathering extent information.
4343 * ext4_ext_fiemap_cb will push extents back to user.
4344 */
4345 error = ext4_ext_walk_space(inode, start_blk, len_blks,
4346 ext4_ext_fiemap_cb, fieinfo);
4347 }
4348
4349 return error;
4350}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
4 * Written by Alex Tomas <alex@clusterfs.com>
5 *
6 * Architecture independence:
7 * Copyright (c) 2005, Bull S.A.
8 * Written by Pierre Peiffer <pierre.peiffer@bull.net>
9 */
10
11/*
12 * Extents support for EXT4
13 *
14 * TODO:
15 * - ext4*_error() should be used in some situations
16 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
17 * - smart tree reduction
18 */
19
20#include <linux/fs.h>
21#include <linux/time.h>
22#include <linux/jbd2.h>
23#include <linux/highuid.h>
24#include <linux/pagemap.h>
25#include <linux/quotaops.h>
26#include <linux/string.h>
27#include <linux/slab.h>
28#include <linux/uaccess.h>
29#include <linux/fiemap.h>
30#include <linux/backing-dev.h>
31#include "ext4_jbd2.h"
32#include "ext4_extents.h"
33#include "xattr.h"
34
35#include <trace/events/ext4.h>
36
37/*
38 * used by extent splitting.
39 */
40#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
41 due to ENOSPC */
42#define EXT4_EXT_MARK_UNWRIT1 0x2 /* mark first half unwritten */
43#define EXT4_EXT_MARK_UNWRIT2 0x4 /* mark second half unwritten */
44
45#define EXT4_EXT_DATA_VALID1 0x8 /* first half contains valid data */
46#define EXT4_EXT_DATA_VALID2 0x10 /* second half contains valid data */
47
48static __le32 ext4_extent_block_csum(struct inode *inode,
49 struct ext4_extent_header *eh)
50{
51 struct ext4_inode_info *ei = EXT4_I(inode);
52 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
53 __u32 csum;
54
55 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
56 EXT4_EXTENT_TAIL_OFFSET(eh));
57 return cpu_to_le32(csum);
58}
59
60static int ext4_extent_block_csum_verify(struct inode *inode,
61 struct ext4_extent_header *eh)
62{
63 struct ext4_extent_tail *et;
64
65 if (!ext4_has_metadata_csum(inode->i_sb))
66 return 1;
67
68 et = find_ext4_extent_tail(eh);
69 if (et->et_checksum != ext4_extent_block_csum(inode, eh))
70 return 0;
71 return 1;
72}
73
74static void ext4_extent_block_csum_set(struct inode *inode,
75 struct ext4_extent_header *eh)
76{
77 struct ext4_extent_tail *et;
78
79 if (!ext4_has_metadata_csum(inode->i_sb))
80 return;
81
82 et = find_ext4_extent_tail(eh);
83 et->et_checksum = ext4_extent_block_csum(inode, eh);
84}
85
86static int ext4_split_extent(handle_t *handle,
87 struct inode *inode,
88 struct ext4_ext_path **ppath,
89 struct ext4_map_blocks *map,
90 int split_flag,
91 int flags);
92
93static int ext4_split_extent_at(handle_t *handle,
94 struct inode *inode,
95 struct ext4_ext_path **ppath,
96 ext4_lblk_t split,
97 int split_flag,
98 int flags);
99
100static int ext4_find_delayed_extent(struct inode *inode,
101 struct extent_status *newes);
102
103static int ext4_ext_truncate_extend_restart(handle_t *handle,
104 struct inode *inode,
105 int needed)
106{
107 int err;
108
109 if (!ext4_handle_valid(handle))
110 return 0;
111 if (handle->h_buffer_credits >= needed)
112 return 0;
113 /*
114 * If we need to extend the journal get a few extra blocks
115 * while we're at it for efficiency's sake.
116 */
117 needed += 3;
118 err = ext4_journal_extend(handle, needed - handle->h_buffer_credits);
119 if (err <= 0)
120 return err;
121 err = ext4_truncate_restart_trans(handle, inode, needed);
122 if (err == 0)
123 err = -EAGAIN;
124
125 return err;
126}
127
128/*
129 * could return:
130 * - EROFS
131 * - ENOMEM
132 */
133static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
134 struct ext4_ext_path *path)
135{
136 if (path->p_bh) {
137 /* path points to block */
138 BUFFER_TRACE(path->p_bh, "get_write_access");
139 return ext4_journal_get_write_access(handle, path->p_bh);
140 }
141 /* path points to leaf/index in inode body */
142 /* we use in-core data, no need to protect them */
143 return 0;
144}
145
146/*
147 * could return:
148 * - EROFS
149 * - ENOMEM
150 * - EIO
151 */
152int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
153 struct inode *inode, struct ext4_ext_path *path)
154{
155 int err;
156
157 WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
158 if (path->p_bh) {
159 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
160 /* path points to block */
161 err = __ext4_handle_dirty_metadata(where, line, handle,
162 inode, path->p_bh);
163 } else {
164 /* path points to leaf/index in inode body */
165 err = ext4_mark_inode_dirty(handle, inode);
166 }
167 return err;
168}
169
170static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
171 struct ext4_ext_path *path,
172 ext4_lblk_t block)
173{
174 if (path) {
175 int depth = path->p_depth;
176 struct ext4_extent *ex;
177
178 /*
179 * Try to predict block placement assuming that we are
180 * filling in a file which will eventually be
181 * non-sparse --- i.e., in the case of libbfd writing
182 * an ELF object sections out-of-order but in a way
183 * the eventually results in a contiguous object or
184 * executable file, or some database extending a table
185 * space file. However, this is actually somewhat
186 * non-ideal if we are writing a sparse file such as
187 * qemu or KVM writing a raw image file that is going
188 * to stay fairly sparse, since it will end up
189 * fragmenting the file system's free space. Maybe we
190 * should have some hueristics or some way to allow
191 * userspace to pass a hint to file system,
192 * especially if the latter case turns out to be
193 * common.
194 */
195 ex = path[depth].p_ext;
196 if (ex) {
197 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
198 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
199
200 if (block > ext_block)
201 return ext_pblk + (block - ext_block);
202 else
203 return ext_pblk - (ext_block - block);
204 }
205
206 /* it looks like index is empty;
207 * try to find starting block from index itself */
208 if (path[depth].p_bh)
209 return path[depth].p_bh->b_blocknr;
210 }
211
212 /* OK. use inode's group */
213 return ext4_inode_to_goal_block(inode);
214}
215
216/*
217 * Allocation for a meta data block
218 */
219static ext4_fsblk_t
220ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
221 struct ext4_ext_path *path,
222 struct ext4_extent *ex, int *err, unsigned int flags)
223{
224 ext4_fsblk_t goal, newblock;
225
226 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
227 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
228 NULL, err);
229 return newblock;
230}
231
232static inline int ext4_ext_space_block(struct inode *inode, int check)
233{
234 int size;
235
236 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
237 / sizeof(struct ext4_extent);
238#ifdef AGGRESSIVE_TEST
239 if (!check && size > 6)
240 size = 6;
241#endif
242 return size;
243}
244
245static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
246{
247 int size;
248
249 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
250 / sizeof(struct ext4_extent_idx);
251#ifdef AGGRESSIVE_TEST
252 if (!check && size > 5)
253 size = 5;
254#endif
255 return size;
256}
257
258static inline int ext4_ext_space_root(struct inode *inode, int check)
259{
260 int size;
261
262 size = sizeof(EXT4_I(inode)->i_data);
263 size -= sizeof(struct ext4_extent_header);
264 size /= sizeof(struct ext4_extent);
265#ifdef AGGRESSIVE_TEST
266 if (!check && size > 3)
267 size = 3;
268#endif
269 return size;
270}
271
272static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
273{
274 int size;
275
276 size = sizeof(EXT4_I(inode)->i_data);
277 size -= sizeof(struct ext4_extent_header);
278 size /= sizeof(struct ext4_extent_idx);
279#ifdef AGGRESSIVE_TEST
280 if (!check && size > 4)
281 size = 4;
282#endif
283 return size;
284}
285
286static inline int
287ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
288 struct ext4_ext_path **ppath, ext4_lblk_t lblk,
289 int nofail)
290{
291 struct ext4_ext_path *path = *ppath;
292 int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
293
294 return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
295 EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
296 EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
297 (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
298}
299
300/*
301 * Calculate the number of metadata blocks needed
302 * to allocate @blocks
303 * Worse case is one block per extent
304 */
305int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
306{
307 struct ext4_inode_info *ei = EXT4_I(inode);
308 int idxs;
309
310 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
311 / sizeof(struct ext4_extent_idx));
312
313 /*
314 * If the new delayed allocation block is contiguous with the
315 * previous da block, it can share index blocks with the
316 * previous block, so we only need to allocate a new index
317 * block every idxs leaf blocks. At ldxs**2 blocks, we need
318 * an additional index block, and at ldxs**3 blocks, yet
319 * another index blocks.
320 */
321 if (ei->i_da_metadata_calc_len &&
322 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
323 int num = 0;
324
325 if ((ei->i_da_metadata_calc_len % idxs) == 0)
326 num++;
327 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
328 num++;
329 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
330 num++;
331 ei->i_da_metadata_calc_len = 0;
332 } else
333 ei->i_da_metadata_calc_len++;
334 ei->i_da_metadata_calc_last_lblock++;
335 return num;
336 }
337
338 /*
339 * In the worst case we need a new set of index blocks at
340 * every level of the inode's extent tree.
341 */
342 ei->i_da_metadata_calc_len = 1;
343 ei->i_da_metadata_calc_last_lblock = lblock;
344 return ext_depth(inode) + 1;
345}
346
347static int
348ext4_ext_max_entries(struct inode *inode, int depth)
349{
350 int max;
351
352 if (depth == ext_depth(inode)) {
353 if (depth == 0)
354 max = ext4_ext_space_root(inode, 1);
355 else
356 max = ext4_ext_space_root_idx(inode, 1);
357 } else {
358 if (depth == 0)
359 max = ext4_ext_space_block(inode, 1);
360 else
361 max = ext4_ext_space_block_idx(inode, 1);
362 }
363
364 return max;
365}
366
367static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
368{
369 ext4_fsblk_t block = ext4_ext_pblock(ext);
370 int len = ext4_ext_get_actual_len(ext);
371 ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
372
373 /*
374 * We allow neither:
375 * - zero length
376 * - overflow/wrap-around
377 */
378 if (lblock + len <= lblock)
379 return 0;
380 return ext4_data_block_valid(EXT4_SB(inode->i_sb), 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_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
389}
390
391static int ext4_valid_extent_entries(struct inode *inode,
392 struct ext4_extent_header *eh,
393 int depth)
394{
395 unsigned short entries;
396 if (eh->eh_entries == 0)
397 return 1;
398
399 entries = le16_to_cpu(eh->eh_entries);
400
401 if (depth == 0) {
402 /* leaf entries */
403 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
404 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
405 ext4_fsblk_t pblock = 0;
406 ext4_lblk_t lblock = 0;
407 ext4_lblk_t prev = 0;
408 int len = 0;
409 while (entries) {
410 if (!ext4_valid_extent(inode, ext))
411 return 0;
412
413 /* Check for overlapping extents */
414 lblock = le32_to_cpu(ext->ee_block);
415 len = ext4_ext_get_actual_len(ext);
416 if ((lblock <= prev) && prev) {
417 pblock = ext4_ext_pblock(ext);
418 es->s_last_error_block = cpu_to_le64(pblock);
419 return 0;
420 }
421 ext++;
422 entries--;
423 prev = lblock + len - 1;
424 }
425 } else {
426 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
427 while (entries) {
428 if (!ext4_valid_extent_idx(inode, ext_idx))
429 return 0;
430 ext_idx++;
431 entries--;
432 }
433 }
434 return 1;
435}
436
437static int __ext4_ext_check(const char *function, unsigned int line,
438 struct inode *inode, struct ext4_extent_header *eh,
439 int depth, ext4_fsblk_t pblk)
440{
441 const char *error_msg;
442 int max = 0, err = -EFSCORRUPTED;
443
444 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
445 error_msg = "invalid magic";
446 goto corrupted;
447 }
448 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
449 error_msg = "unexpected eh_depth";
450 goto corrupted;
451 }
452 if (unlikely(eh->eh_max == 0)) {
453 error_msg = "invalid eh_max";
454 goto corrupted;
455 }
456 max = ext4_ext_max_entries(inode, depth);
457 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
458 error_msg = "too large eh_max";
459 goto corrupted;
460 }
461 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
462 error_msg = "invalid eh_entries";
463 goto corrupted;
464 }
465 if (!ext4_valid_extent_entries(inode, eh, depth)) {
466 error_msg = "invalid extent entries";
467 goto corrupted;
468 }
469 if (unlikely(depth > 32)) {
470 error_msg = "too large eh_depth";
471 goto corrupted;
472 }
473 /* Verify checksum on non-root extent tree nodes */
474 if (ext_depth(inode) != depth &&
475 !ext4_extent_block_csum_verify(inode, eh)) {
476 error_msg = "extent tree corrupted";
477 err = -EFSBADCRC;
478 goto corrupted;
479 }
480 return 0;
481
482corrupted:
483 ext4_error_inode(inode, function, line, 0,
484 "pblk %llu bad header/extent: %s - magic %x, "
485 "entries %u, max %u(%u), depth %u(%u)",
486 (unsigned long long) pblk, error_msg,
487 le16_to_cpu(eh->eh_magic),
488 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
489 max, le16_to_cpu(eh->eh_depth), depth);
490 return err;
491}
492
493#define ext4_ext_check(inode, eh, depth, pblk) \
494 __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
495
496int ext4_ext_check_inode(struct inode *inode)
497{
498 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
499}
500
501static struct buffer_head *
502__read_extent_tree_block(const char *function, unsigned int line,
503 struct inode *inode, ext4_fsblk_t pblk, int depth,
504 int flags)
505{
506 struct buffer_head *bh;
507 int err;
508
509 bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
510 if (unlikely(!bh))
511 return ERR_PTR(-ENOMEM);
512
513 if (!bh_uptodate_or_lock(bh)) {
514 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
515 err = bh_submit_read(bh);
516 if (err < 0)
517 goto errout;
518 }
519 if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
520 return bh;
521 if (!ext4_has_feature_journal(inode->i_sb) ||
522 (inode->i_ino !=
523 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum))) {
524 err = __ext4_ext_check(function, line, inode,
525 ext_block_hdr(bh), depth, pblk);
526 if (err)
527 goto errout;
528 }
529 set_buffer_verified(bh);
530 /*
531 * If this is a leaf block, cache all of its entries
532 */
533 if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
534 struct ext4_extent_header *eh = ext_block_hdr(bh);
535 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
536 ext4_lblk_t prev = 0;
537 int i;
538
539 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
540 unsigned int status = EXTENT_STATUS_WRITTEN;
541 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
542 int len = ext4_ext_get_actual_len(ex);
543
544 if (prev && (prev != lblk))
545 ext4_es_cache_extent(inode, prev,
546 lblk - prev, ~0,
547 EXTENT_STATUS_HOLE);
548
549 if (ext4_ext_is_unwritten(ex))
550 status = EXTENT_STATUS_UNWRITTEN;
551 ext4_es_cache_extent(inode, lblk, len,
552 ext4_ext_pblock(ex), status);
553 prev = lblk + len;
554 }
555 }
556 return bh;
557errout:
558 put_bh(bh);
559 return ERR_PTR(err);
560
561}
562
563#define read_extent_tree_block(inode, pblk, depth, flags) \
564 __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \
565 (depth), (flags))
566
567/*
568 * This function is called to cache a file's extent information in the
569 * extent status tree
570 */
571int ext4_ext_precache(struct inode *inode)
572{
573 struct ext4_inode_info *ei = EXT4_I(inode);
574 struct ext4_ext_path *path = NULL;
575 struct buffer_head *bh;
576 int i = 0, depth, ret = 0;
577
578 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
579 return 0; /* not an extent-mapped inode */
580
581 down_read(&ei->i_data_sem);
582 depth = ext_depth(inode);
583
584 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
585 GFP_NOFS);
586 if (path == NULL) {
587 up_read(&ei->i_data_sem);
588 return -ENOMEM;
589 }
590
591 /* Don't cache anything if there are no external extent blocks */
592 if (depth == 0)
593 goto out;
594 path[0].p_hdr = ext_inode_hdr(inode);
595 ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
596 if (ret)
597 goto out;
598 path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
599 while (i >= 0) {
600 /*
601 * If this is a leaf block or we've reached the end of
602 * the index block, go up
603 */
604 if ((i == depth) ||
605 path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
606 brelse(path[i].p_bh);
607 path[i].p_bh = NULL;
608 i--;
609 continue;
610 }
611 bh = read_extent_tree_block(inode,
612 ext4_idx_pblock(path[i].p_idx++),
613 depth - i - 1,
614 EXT4_EX_FORCE_CACHE);
615 if (IS_ERR(bh)) {
616 ret = PTR_ERR(bh);
617 break;
618 }
619 i++;
620 path[i].p_bh = bh;
621 path[i].p_hdr = ext_block_hdr(bh);
622 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
623 }
624 ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
625out:
626 up_read(&ei->i_data_sem);
627 ext4_ext_drop_refs(path);
628 kfree(path);
629 return ret;
630}
631
632#ifdef EXT_DEBUG
633static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
634{
635 int k, l = path->p_depth;
636
637 ext_debug("path:");
638 for (k = 0; k <= l; k++, path++) {
639 if (path->p_idx) {
640 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
641 ext4_idx_pblock(path->p_idx));
642 } else if (path->p_ext) {
643 ext_debug(" %d:[%d]%d:%llu ",
644 le32_to_cpu(path->p_ext->ee_block),
645 ext4_ext_is_unwritten(path->p_ext),
646 ext4_ext_get_actual_len(path->p_ext),
647 ext4_ext_pblock(path->p_ext));
648 } else
649 ext_debug(" []");
650 }
651 ext_debug("\n");
652}
653
654static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
655{
656 int depth = ext_depth(inode);
657 struct ext4_extent_header *eh;
658 struct ext4_extent *ex;
659 int i;
660
661 if (!path)
662 return;
663
664 eh = path[depth].p_hdr;
665 ex = EXT_FIRST_EXTENT(eh);
666
667 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
668
669 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
670 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
671 ext4_ext_is_unwritten(ex),
672 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
673 }
674 ext_debug("\n");
675}
676
677static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
678 ext4_fsblk_t newblock, int level)
679{
680 int depth = ext_depth(inode);
681 struct ext4_extent *ex;
682
683 if (depth != level) {
684 struct ext4_extent_idx *idx;
685 idx = path[level].p_idx;
686 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
687 ext_debug("%d: move %d:%llu in new index %llu\n", level,
688 le32_to_cpu(idx->ei_block),
689 ext4_idx_pblock(idx),
690 newblock);
691 idx++;
692 }
693
694 return;
695 }
696
697 ex = path[depth].p_ext;
698 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
699 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
700 le32_to_cpu(ex->ee_block),
701 ext4_ext_pblock(ex),
702 ext4_ext_is_unwritten(ex),
703 ext4_ext_get_actual_len(ex),
704 newblock);
705 ex++;
706 }
707}
708
709#else
710#define ext4_ext_show_path(inode, path)
711#define ext4_ext_show_leaf(inode, path)
712#define ext4_ext_show_move(inode, path, newblock, level)
713#endif
714
715void ext4_ext_drop_refs(struct ext4_ext_path *path)
716{
717 int depth, i;
718
719 if (!path)
720 return;
721 depth = path->p_depth;
722 for (i = 0; i <= depth; i++, path++)
723 if (path->p_bh) {
724 brelse(path->p_bh);
725 path->p_bh = NULL;
726 }
727}
728
729/*
730 * ext4_ext_binsearch_idx:
731 * binary search for the closest index of the given block
732 * the header must be checked before calling this
733 */
734static void
735ext4_ext_binsearch_idx(struct inode *inode,
736 struct ext4_ext_path *path, ext4_lblk_t block)
737{
738 struct ext4_extent_header *eh = path->p_hdr;
739 struct ext4_extent_idx *r, *l, *m;
740
741
742 ext_debug("binsearch for %u(idx): ", block);
743
744 l = EXT_FIRST_INDEX(eh) + 1;
745 r = EXT_LAST_INDEX(eh);
746 while (l <= r) {
747 m = l + (r - l) / 2;
748 if (block < le32_to_cpu(m->ei_block))
749 r = m - 1;
750 else
751 l = m + 1;
752 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
753 m, le32_to_cpu(m->ei_block),
754 r, le32_to_cpu(r->ei_block));
755 }
756
757 path->p_idx = l - 1;
758 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
759 ext4_idx_pblock(path->p_idx));
760
761#ifdef CHECK_BINSEARCH
762 {
763 struct ext4_extent_idx *chix, *ix;
764 int k;
765
766 chix = ix = EXT_FIRST_INDEX(eh);
767 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
768 if (k != 0 &&
769 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
770 printk(KERN_DEBUG "k=%d, ix=0x%p, "
771 "first=0x%p\n", k,
772 ix, EXT_FIRST_INDEX(eh));
773 printk(KERN_DEBUG "%u <= %u\n",
774 le32_to_cpu(ix->ei_block),
775 le32_to_cpu(ix[-1].ei_block));
776 }
777 BUG_ON(k && le32_to_cpu(ix->ei_block)
778 <= le32_to_cpu(ix[-1].ei_block));
779 if (block < le32_to_cpu(ix->ei_block))
780 break;
781 chix = ix;
782 }
783 BUG_ON(chix != path->p_idx);
784 }
785#endif
786
787}
788
789/*
790 * ext4_ext_binsearch:
791 * binary search for closest extent of the given block
792 * the header must be checked before calling this
793 */
794static void
795ext4_ext_binsearch(struct inode *inode,
796 struct ext4_ext_path *path, ext4_lblk_t block)
797{
798 struct ext4_extent_header *eh = path->p_hdr;
799 struct ext4_extent *r, *l, *m;
800
801 if (eh->eh_entries == 0) {
802 /*
803 * this leaf is empty:
804 * we get such a leaf in split/add case
805 */
806 return;
807 }
808
809 ext_debug("binsearch for %u: ", block);
810
811 l = EXT_FIRST_EXTENT(eh) + 1;
812 r = EXT_LAST_EXTENT(eh);
813
814 while (l <= r) {
815 m = l + (r - l) / 2;
816 if (block < le32_to_cpu(m->ee_block))
817 r = m - 1;
818 else
819 l = m + 1;
820 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
821 m, le32_to_cpu(m->ee_block),
822 r, le32_to_cpu(r->ee_block));
823 }
824
825 path->p_ext = l - 1;
826 ext_debug(" -> %d:%llu:[%d]%d ",
827 le32_to_cpu(path->p_ext->ee_block),
828 ext4_ext_pblock(path->p_ext),
829 ext4_ext_is_unwritten(path->p_ext),
830 ext4_ext_get_actual_len(path->p_ext));
831
832#ifdef CHECK_BINSEARCH
833 {
834 struct ext4_extent *chex, *ex;
835 int k;
836
837 chex = ex = EXT_FIRST_EXTENT(eh);
838 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
839 BUG_ON(k && le32_to_cpu(ex->ee_block)
840 <= le32_to_cpu(ex[-1].ee_block));
841 if (block < le32_to_cpu(ex->ee_block))
842 break;
843 chex = ex;
844 }
845 BUG_ON(chex != path->p_ext);
846 }
847#endif
848
849}
850
851int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
852{
853 struct ext4_extent_header *eh;
854
855 eh = ext_inode_hdr(inode);
856 eh->eh_depth = 0;
857 eh->eh_entries = 0;
858 eh->eh_magic = EXT4_EXT_MAGIC;
859 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
860 ext4_mark_inode_dirty(handle, inode);
861 return 0;
862}
863
864struct ext4_ext_path *
865ext4_find_extent(struct inode *inode, ext4_lblk_t block,
866 struct ext4_ext_path **orig_path, int flags)
867{
868 struct ext4_extent_header *eh;
869 struct buffer_head *bh;
870 struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
871 short int depth, i, ppos = 0;
872 int ret;
873
874 eh = ext_inode_hdr(inode);
875 depth = ext_depth(inode);
876 if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
877 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
878 depth);
879 ret = -EFSCORRUPTED;
880 goto err;
881 }
882
883 if (path) {
884 ext4_ext_drop_refs(path);
885 if (depth > path[0].p_maxdepth) {
886 kfree(path);
887 *orig_path = path = NULL;
888 }
889 }
890 if (!path) {
891 /* account possible depth increase */
892 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
893 GFP_NOFS);
894 if (unlikely(!path))
895 return ERR_PTR(-ENOMEM);
896 path[0].p_maxdepth = depth + 1;
897 }
898 path[0].p_hdr = eh;
899 path[0].p_bh = NULL;
900
901 i = depth;
902 /* walk through the tree */
903 while (i) {
904 ext_debug("depth %d: num %d, max %d\n",
905 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
906
907 ext4_ext_binsearch_idx(inode, path + ppos, block);
908 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
909 path[ppos].p_depth = i;
910 path[ppos].p_ext = NULL;
911
912 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
913 flags);
914 if (IS_ERR(bh)) {
915 ret = PTR_ERR(bh);
916 goto err;
917 }
918
919 eh = ext_block_hdr(bh);
920 ppos++;
921 path[ppos].p_bh = bh;
922 path[ppos].p_hdr = eh;
923 }
924
925 path[ppos].p_depth = i;
926 path[ppos].p_ext = NULL;
927 path[ppos].p_idx = NULL;
928
929 /* find extent */
930 ext4_ext_binsearch(inode, path + ppos, block);
931 /* if not an empty leaf */
932 if (path[ppos].p_ext)
933 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
934
935 ext4_ext_show_path(inode, path);
936
937 return path;
938
939err:
940 ext4_ext_drop_refs(path);
941 kfree(path);
942 if (orig_path)
943 *orig_path = NULL;
944 return ERR_PTR(ret);
945}
946
947/*
948 * ext4_ext_insert_index:
949 * insert new index [@logical;@ptr] into the block at @curp;
950 * check where to insert: before @curp or after @curp
951 */
952static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
953 struct ext4_ext_path *curp,
954 int logical, ext4_fsblk_t ptr)
955{
956 struct ext4_extent_idx *ix;
957 int len, err;
958
959 err = ext4_ext_get_access(handle, inode, curp);
960 if (err)
961 return err;
962
963 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
964 EXT4_ERROR_INODE(inode,
965 "logical %d == ei_block %d!",
966 logical, le32_to_cpu(curp->p_idx->ei_block));
967 return -EFSCORRUPTED;
968 }
969
970 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
971 >= le16_to_cpu(curp->p_hdr->eh_max))) {
972 EXT4_ERROR_INODE(inode,
973 "eh_entries %d >= eh_max %d!",
974 le16_to_cpu(curp->p_hdr->eh_entries),
975 le16_to_cpu(curp->p_hdr->eh_max));
976 return -EFSCORRUPTED;
977 }
978
979 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
980 /* insert after */
981 ext_debug("insert new index %d after: %llu\n", logical, ptr);
982 ix = curp->p_idx + 1;
983 } else {
984 /* insert before */
985 ext_debug("insert new index %d before: %llu\n", logical, ptr);
986 ix = curp->p_idx;
987 }
988
989 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
990 BUG_ON(len < 0);
991 if (len > 0) {
992 ext_debug("insert new index %d: "
993 "move %d indices from 0x%p to 0x%p\n",
994 logical, len, ix, ix + 1);
995 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
996 }
997
998 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
999 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
1000 return -EFSCORRUPTED;
1001 }
1002
1003 ix->ei_block = cpu_to_le32(logical);
1004 ext4_idx_store_pblock(ix, ptr);
1005 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1006
1007 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1008 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1009 return -EFSCORRUPTED;
1010 }
1011
1012 err = ext4_ext_dirty(handle, inode, curp);
1013 ext4_std_error(inode->i_sb, err);
1014
1015 return err;
1016}
1017
1018/*
1019 * ext4_ext_split:
1020 * inserts new subtree into the path, using free index entry
1021 * at depth @at:
1022 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1023 * - makes decision where to split
1024 * - moves remaining extents and index entries (right to the split point)
1025 * into the newly allocated blocks
1026 * - initializes subtree
1027 */
1028static int ext4_ext_split(handle_t *handle, struct inode *inode,
1029 unsigned int flags,
1030 struct ext4_ext_path *path,
1031 struct ext4_extent *newext, int at)
1032{
1033 struct buffer_head *bh = NULL;
1034 int depth = ext_depth(inode);
1035 struct ext4_extent_header *neh;
1036 struct ext4_extent_idx *fidx;
1037 int i = at, k, m, a;
1038 ext4_fsblk_t newblock, oldblock;
1039 __le32 border;
1040 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1041 int err = 0;
1042 size_t ext_size = 0;
1043
1044 /* make decision: where to split? */
1045 /* FIXME: now decision is simplest: at current extent */
1046
1047 /* if current leaf will be split, then we should use
1048 * border from split point */
1049 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1050 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1051 return -EFSCORRUPTED;
1052 }
1053 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1054 border = path[depth].p_ext[1].ee_block;
1055 ext_debug("leaf will be split."
1056 " next leaf starts at %d\n",
1057 le32_to_cpu(border));
1058 } else {
1059 border = newext->ee_block;
1060 ext_debug("leaf will be added."
1061 " next leaf starts at %d\n",
1062 le32_to_cpu(border));
1063 }
1064
1065 /*
1066 * If error occurs, then we break processing
1067 * and mark filesystem read-only. index won't
1068 * be inserted and tree will be in consistent
1069 * state. Next mount will repair buffers too.
1070 */
1071
1072 /*
1073 * Get array to track all allocated blocks.
1074 * We need this to handle errors and free blocks
1075 * upon them.
1076 */
1077 ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), GFP_NOFS);
1078 if (!ablocks)
1079 return -ENOMEM;
1080
1081 /* allocate all needed blocks */
1082 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1083 for (a = 0; a < depth - at; a++) {
1084 newblock = ext4_ext_new_meta_block(handle, inode, path,
1085 newext, &err, flags);
1086 if (newblock == 0)
1087 goto cleanup;
1088 ablocks[a] = newblock;
1089 }
1090
1091 /* initialize new leaf */
1092 newblock = ablocks[--a];
1093 if (unlikely(newblock == 0)) {
1094 EXT4_ERROR_INODE(inode, "newblock == 0!");
1095 err = -EFSCORRUPTED;
1096 goto cleanup;
1097 }
1098 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1099 if (unlikely(!bh)) {
1100 err = -ENOMEM;
1101 goto cleanup;
1102 }
1103 lock_buffer(bh);
1104
1105 err = ext4_journal_get_create_access(handle, bh);
1106 if (err)
1107 goto cleanup;
1108
1109 neh = ext_block_hdr(bh);
1110 neh->eh_entries = 0;
1111 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1112 neh->eh_magic = EXT4_EXT_MAGIC;
1113 neh->eh_depth = 0;
1114
1115 /* move remainder of path[depth] to the new leaf */
1116 if (unlikely(path[depth].p_hdr->eh_entries !=
1117 path[depth].p_hdr->eh_max)) {
1118 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1119 path[depth].p_hdr->eh_entries,
1120 path[depth].p_hdr->eh_max);
1121 err = -EFSCORRUPTED;
1122 goto cleanup;
1123 }
1124 /* start copy from next extent */
1125 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1126 ext4_ext_show_move(inode, path, newblock, depth);
1127 if (m) {
1128 struct ext4_extent *ex;
1129 ex = EXT_FIRST_EXTENT(neh);
1130 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1131 le16_add_cpu(&neh->eh_entries, m);
1132 }
1133
1134 /* zero out unused area in the extent block */
1135 ext_size = sizeof(struct ext4_extent_header) +
1136 sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1137 memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1138 ext4_extent_block_csum_set(inode, neh);
1139 set_buffer_uptodate(bh);
1140 unlock_buffer(bh);
1141
1142 err = ext4_handle_dirty_metadata(handle, inode, bh);
1143 if (err)
1144 goto cleanup;
1145 brelse(bh);
1146 bh = NULL;
1147
1148 /* correct old leaf */
1149 if (m) {
1150 err = ext4_ext_get_access(handle, inode, path + depth);
1151 if (err)
1152 goto cleanup;
1153 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1154 err = ext4_ext_dirty(handle, inode, path + depth);
1155 if (err)
1156 goto cleanup;
1157
1158 }
1159
1160 /* create intermediate indexes */
1161 k = depth - at - 1;
1162 if (unlikely(k < 0)) {
1163 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1164 err = -EFSCORRUPTED;
1165 goto cleanup;
1166 }
1167 if (k)
1168 ext_debug("create %d intermediate indices\n", k);
1169 /* insert new index into current index block */
1170 /* current depth stored in i var */
1171 i = depth - 1;
1172 while (k--) {
1173 oldblock = newblock;
1174 newblock = ablocks[--a];
1175 bh = sb_getblk(inode->i_sb, newblock);
1176 if (unlikely(!bh)) {
1177 err = -ENOMEM;
1178 goto cleanup;
1179 }
1180 lock_buffer(bh);
1181
1182 err = ext4_journal_get_create_access(handle, bh);
1183 if (err)
1184 goto cleanup;
1185
1186 neh = ext_block_hdr(bh);
1187 neh->eh_entries = cpu_to_le16(1);
1188 neh->eh_magic = EXT4_EXT_MAGIC;
1189 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1190 neh->eh_depth = cpu_to_le16(depth - i);
1191 fidx = EXT_FIRST_INDEX(neh);
1192 fidx->ei_block = border;
1193 ext4_idx_store_pblock(fidx, oldblock);
1194
1195 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1196 i, newblock, le32_to_cpu(border), oldblock);
1197
1198 /* move remainder of path[i] to the new index block */
1199 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1200 EXT_LAST_INDEX(path[i].p_hdr))) {
1201 EXT4_ERROR_INODE(inode,
1202 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1203 le32_to_cpu(path[i].p_ext->ee_block));
1204 err = -EFSCORRUPTED;
1205 goto cleanup;
1206 }
1207 /* start copy indexes */
1208 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1209 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1210 EXT_MAX_INDEX(path[i].p_hdr));
1211 ext4_ext_show_move(inode, path, newblock, i);
1212 if (m) {
1213 memmove(++fidx, path[i].p_idx,
1214 sizeof(struct ext4_extent_idx) * m);
1215 le16_add_cpu(&neh->eh_entries, m);
1216 }
1217 /* zero out unused area in the extent block */
1218 ext_size = sizeof(struct ext4_extent_header) +
1219 (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1220 memset(bh->b_data + ext_size, 0,
1221 inode->i_sb->s_blocksize - ext_size);
1222 ext4_extent_block_csum_set(inode, neh);
1223 set_buffer_uptodate(bh);
1224 unlock_buffer(bh);
1225
1226 err = ext4_handle_dirty_metadata(handle, inode, bh);
1227 if (err)
1228 goto cleanup;
1229 brelse(bh);
1230 bh = NULL;
1231
1232 /* correct old index */
1233 if (m) {
1234 err = ext4_ext_get_access(handle, inode, path + i);
1235 if (err)
1236 goto cleanup;
1237 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1238 err = ext4_ext_dirty(handle, inode, path + i);
1239 if (err)
1240 goto cleanup;
1241 }
1242
1243 i--;
1244 }
1245
1246 /* insert new index */
1247 err = ext4_ext_insert_index(handle, inode, path + at,
1248 le32_to_cpu(border), newblock);
1249
1250cleanup:
1251 if (bh) {
1252 if (buffer_locked(bh))
1253 unlock_buffer(bh);
1254 brelse(bh);
1255 }
1256
1257 if (err) {
1258 /* free all allocated blocks in error case */
1259 for (i = 0; i < depth; i++) {
1260 if (!ablocks[i])
1261 continue;
1262 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1263 EXT4_FREE_BLOCKS_METADATA);
1264 }
1265 }
1266 kfree(ablocks);
1267
1268 return err;
1269}
1270
1271/*
1272 * ext4_ext_grow_indepth:
1273 * implements tree growing procedure:
1274 * - allocates new block
1275 * - moves top-level data (index block or leaf) into the new block
1276 * - initializes new top-level, creating index that points to the
1277 * just created block
1278 */
1279static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1280 unsigned int flags)
1281{
1282 struct ext4_extent_header *neh;
1283 struct buffer_head *bh;
1284 ext4_fsblk_t newblock, goal = 0;
1285 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1286 int err = 0;
1287 size_t ext_size = 0;
1288
1289 /* Try to prepend new index to old one */
1290 if (ext_depth(inode))
1291 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1292 if (goal > le32_to_cpu(es->s_first_data_block)) {
1293 flags |= EXT4_MB_HINT_TRY_GOAL;
1294 goal--;
1295 } else
1296 goal = ext4_inode_to_goal_block(inode);
1297 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1298 NULL, &err);
1299 if (newblock == 0)
1300 return err;
1301
1302 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1303 if (unlikely(!bh))
1304 return -ENOMEM;
1305 lock_buffer(bh);
1306
1307 err = ext4_journal_get_create_access(handle, bh);
1308 if (err) {
1309 unlock_buffer(bh);
1310 goto out;
1311 }
1312
1313 ext_size = sizeof(EXT4_I(inode)->i_data);
1314 /* move top-level index/leaf into new block */
1315 memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1316 /* zero out unused area in the extent block */
1317 memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1318
1319 /* set size of new block */
1320 neh = ext_block_hdr(bh);
1321 /* old root could have indexes or leaves
1322 * so calculate e_max right way */
1323 if (ext_depth(inode))
1324 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1325 else
1326 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1327 neh->eh_magic = EXT4_EXT_MAGIC;
1328 ext4_extent_block_csum_set(inode, neh);
1329 set_buffer_uptodate(bh);
1330 unlock_buffer(bh);
1331
1332 err = ext4_handle_dirty_metadata(handle, inode, bh);
1333 if (err)
1334 goto out;
1335
1336 /* Update top-level index: num,max,pointer */
1337 neh = ext_inode_hdr(inode);
1338 neh->eh_entries = cpu_to_le16(1);
1339 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1340 if (neh->eh_depth == 0) {
1341 /* Root extent block becomes index block */
1342 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1343 EXT_FIRST_INDEX(neh)->ei_block =
1344 EXT_FIRST_EXTENT(neh)->ee_block;
1345 }
1346 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1347 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1348 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1349 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1350
1351 le16_add_cpu(&neh->eh_depth, 1);
1352 ext4_mark_inode_dirty(handle, inode);
1353out:
1354 brelse(bh);
1355
1356 return err;
1357}
1358
1359/*
1360 * ext4_ext_create_new_leaf:
1361 * finds empty index and adds new leaf.
1362 * if no free index is found, then it requests in-depth growing.
1363 */
1364static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1365 unsigned int mb_flags,
1366 unsigned int gb_flags,
1367 struct ext4_ext_path **ppath,
1368 struct ext4_extent *newext)
1369{
1370 struct ext4_ext_path *path = *ppath;
1371 struct ext4_ext_path *curp;
1372 int depth, i, err = 0;
1373
1374repeat:
1375 i = depth = ext_depth(inode);
1376
1377 /* walk up to the tree and look for free index entry */
1378 curp = path + depth;
1379 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1380 i--;
1381 curp--;
1382 }
1383
1384 /* we use already allocated block for index block,
1385 * so subsequent data blocks should be contiguous */
1386 if (EXT_HAS_FREE_INDEX(curp)) {
1387 /* if we found index with free entry, then use that
1388 * entry: create all needed subtree and add new leaf */
1389 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1390 if (err)
1391 goto out;
1392
1393 /* refill path */
1394 path = ext4_find_extent(inode,
1395 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1396 ppath, gb_flags);
1397 if (IS_ERR(path))
1398 err = PTR_ERR(path);
1399 } else {
1400 /* tree is full, time to grow in depth */
1401 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1402 if (err)
1403 goto out;
1404
1405 /* refill path */
1406 path = ext4_find_extent(inode,
1407 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1408 ppath, gb_flags);
1409 if (IS_ERR(path)) {
1410 err = PTR_ERR(path);
1411 goto out;
1412 }
1413
1414 /*
1415 * only first (depth 0 -> 1) produces free space;
1416 * in all other cases we have to split the grown tree
1417 */
1418 depth = ext_depth(inode);
1419 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1420 /* now we need to split */
1421 goto repeat;
1422 }
1423 }
1424
1425out:
1426 return err;
1427}
1428
1429/*
1430 * search the closest allocated block to the left for *logical
1431 * and returns it at @logical + it's physical address at @phys
1432 * if *logical is the smallest allocated block, the function
1433 * returns 0 at @phys
1434 * return value contains 0 (success) or error code
1435 */
1436static int ext4_ext_search_left(struct inode *inode,
1437 struct ext4_ext_path *path,
1438 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1439{
1440 struct ext4_extent_idx *ix;
1441 struct ext4_extent *ex;
1442 int depth, ee_len;
1443
1444 if (unlikely(path == NULL)) {
1445 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1446 return -EFSCORRUPTED;
1447 }
1448 depth = path->p_depth;
1449 *phys = 0;
1450
1451 if (depth == 0 && path->p_ext == NULL)
1452 return 0;
1453
1454 /* usually extent in the path covers blocks smaller
1455 * then *logical, but it can be that extent is the
1456 * first one in the file */
1457
1458 ex = path[depth].p_ext;
1459 ee_len = ext4_ext_get_actual_len(ex);
1460 if (*logical < le32_to_cpu(ex->ee_block)) {
1461 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1462 EXT4_ERROR_INODE(inode,
1463 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1464 *logical, le32_to_cpu(ex->ee_block));
1465 return -EFSCORRUPTED;
1466 }
1467 while (--depth >= 0) {
1468 ix = path[depth].p_idx;
1469 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1470 EXT4_ERROR_INODE(inode,
1471 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1472 ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1473 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1474 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1475 depth);
1476 return -EFSCORRUPTED;
1477 }
1478 }
1479 return 0;
1480 }
1481
1482 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1483 EXT4_ERROR_INODE(inode,
1484 "logical %d < ee_block %d + ee_len %d!",
1485 *logical, le32_to_cpu(ex->ee_block), ee_len);
1486 return -EFSCORRUPTED;
1487 }
1488
1489 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1490 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1491 return 0;
1492}
1493
1494/*
1495 * search the closest allocated block to the right for *logical
1496 * and returns it at @logical + it's physical address at @phys
1497 * if *logical is the largest allocated block, the function
1498 * returns 0 at @phys
1499 * return value contains 0 (success) or error code
1500 */
1501static int ext4_ext_search_right(struct inode *inode,
1502 struct ext4_ext_path *path,
1503 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1504 struct ext4_extent **ret_ex)
1505{
1506 struct buffer_head *bh = NULL;
1507 struct ext4_extent_header *eh;
1508 struct ext4_extent_idx *ix;
1509 struct ext4_extent *ex;
1510 ext4_fsblk_t block;
1511 int depth; /* Note, NOT eh_depth; depth from top of tree */
1512 int ee_len;
1513
1514 if (unlikely(path == NULL)) {
1515 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1516 return -EFSCORRUPTED;
1517 }
1518 depth = path->p_depth;
1519 *phys = 0;
1520
1521 if (depth == 0 && path->p_ext == NULL)
1522 return 0;
1523
1524 /* usually extent in the path covers blocks smaller
1525 * then *logical, but it can be that extent is the
1526 * first one in the file */
1527
1528 ex = path[depth].p_ext;
1529 ee_len = ext4_ext_get_actual_len(ex);
1530 if (*logical < le32_to_cpu(ex->ee_block)) {
1531 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1532 EXT4_ERROR_INODE(inode,
1533 "first_extent(path[%d].p_hdr) != ex",
1534 depth);
1535 return -EFSCORRUPTED;
1536 }
1537 while (--depth >= 0) {
1538 ix = path[depth].p_idx;
1539 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1540 EXT4_ERROR_INODE(inode,
1541 "ix != EXT_FIRST_INDEX *logical %d!",
1542 *logical);
1543 return -EFSCORRUPTED;
1544 }
1545 }
1546 goto found_extent;
1547 }
1548
1549 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1550 EXT4_ERROR_INODE(inode,
1551 "logical %d < ee_block %d + ee_len %d!",
1552 *logical, le32_to_cpu(ex->ee_block), ee_len);
1553 return -EFSCORRUPTED;
1554 }
1555
1556 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1557 /* next allocated block in this leaf */
1558 ex++;
1559 goto found_extent;
1560 }
1561
1562 /* go up and search for index to the right */
1563 while (--depth >= 0) {
1564 ix = path[depth].p_idx;
1565 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1566 goto got_index;
1567 }
1568
1569 /* we've gone up to the root and found no index to the right */
1570 return 0;
1571
1572got_index:
1573 /* we've found index to the right, let's
1574 * follow it and find the closest allocated
1575 * block to the right */
1576 ix++;
1577 block = ext4_idx_pblock(ix);
1578 while (++depth < path->p_depth) {
1579 /* subtract from p_depth to get proper eh_depth */
1580 bh = read_extent_tree_block(inode, block,
1581 path->p_depth - depth, 0);
1582 if (IS_ERR(bh))
1583 return PTR_ERR(bh);
1584 eh = ext_block_hdr(bh);
1585 ix = EXT_FIRST_INDEX(eh);
1586 block = ext4_idx_pblock(ix);
1587 put_bh(bh);
1588 }
1589
1590 bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1591 if (IS_ERR(bh))
1592 return PTR_ERR(bh);
1593 eh = ext_block_hdr(bh);
1594 ex = EXT_FIRST_EXTENT(eh);
1595found_extent:
1596 *logical = le32_to_cpu(ex->ee_block);
1597 *phys = ext4_ext_pblock(ex);
1598 *ret_ex = ex;
1599 if (bh)
1600 put_bh(bh);
1601 return 0;
1602}
1603
1604/*
1605 * ext4_ext_next_allocated_block:
1606 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1607 * NOTE: it considers block number from index entry as
1608 * allocated block. Thus, index entries have to be consistent
1609 * with leaves.
1610 */
1611ext4_lblk_t
1612ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1613{
1614 int depth;
1615
1616 BUG_ON(path == NULL);
1617 depth = path->p_depth;
1618
1619 if (depth == 0 && path->p_ext == NULL)
1620 return EXT_MAX_BLOCKS;
1621
1622 while (depth >= 0) {
1623 if (depth == path->p_depth) {
1624 /* leaf */
1625 if (path[depth].p_ext &&
1626 path[depth].p_ext !=
1627 EXT_LAST_EXTENT(path[depth].p_hdr))
1628 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1629 } else {
1630 /* index */
1631 if (path[depth].p_idx !=
1632 EXT_LAST_INDEX(path[depth].p_hdr))
1633 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1634 }
1635 depth--;
1636 }
1637
1638 return EXT_MAX_BLOCKS;
1639}
1640
1641/*
1642 * ext4_ext_next_leaf_block:
1643 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1644 */
1645static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1646{
1647 int depth;
1648
1649 BUG_ON(path == NULL);
1650 depth = path->p_depth;
1651
1652 /* zero-tree has no leaf blocks at all */
1653 if (depth == 0)
1654 return EXT_MAX_BLOCKS;
1655
1656 /* go to index block */
1657 depth--;
1658
1659 while (depth >= 0) {
1660 if (path[depth].p_idx !=
1661 EXT_LAST_INDEX(path[depth].p_hdr))
1662 return (ext4_lblk_t)
1663 le32_to_cpu(path[depth].p_idx[1].ei_block);
1664 depth--;
1665 }
1666
1667 return EXT_MAX_BLOCKS;
1668}
1669
1670/*
1671 * ext4_ext_correct_indexes:
1672 * if leaf gets modified and modified extent is first in the leaf,
1673 * then we have to correct all indexes above.
1674 * TODO: do we need to correct tree in all cases?
1675 */
1676static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1677 struct ext4_ext_path *path)
1678{
1679 struct ext4_extent_header *eh;
1680 int depth = ext_depth(inode);
1681 struct ext4_extent *ex;
1682 __le32 border;
1683 int k, err = 0;
1684
1685 eh = path[depth].p_hdr;
1686 ex = path[depth].p_ext;
1687
1688 if (unlikely(ex == NULL || eh == NULL)) {
1689 EXT4_ERROR_INODE(inode,
1690 "ex %p == NULL or eh %p == NULL", ex, eh);
1691 return -EFSCORRUPTED;
1692 }
1693
1694 if (depth == 0) {
1695 /* there is no tree at all */
1696 return 0;
1697 }
1698
1699 if (ex != EXT_FIRST_EXTENT(eh)) {
1700 /* we correct tree if first leaf got modified only */
1701 return 0;
1702 }
1703
1704 /*
1705 * TODO: we need correction if border is smaller than current one
1706 */
1707 k = depth - 1;
1708 border = path[depth].p_ext->ee_block;
1709 err = ext4_ext_get_access(handle, inode, path + k);
1710 if (err)
1711 return err;
1712 path[k].p_idx->ei_block = border;
1713 err = ext4_ext_dirty(handle, inode, path + k);
1714 if (err)
1715 return err;
1716
1717 while (k--) {
1718 /* change all left-side indexes */
1719 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1720 break;
1721 err = ext4_ext_get_access(handle, inode, path + k);
1722 if (err)
1723 break;
1724 path[k].p_idx->ei_block = border;
1725 err = ext4_ext_dirty(handle, inode, path + k);
1726 if (err)
1727 break;
1728 }
1729
1730 return err;
1731}
1732
1733int
1734ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1735 struct ext4_extent *ex2)
1736{
1737 unsigned short ext1_ee_len, ext2_ee_len;
1738
1739 if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1740 return 0;
1741
1742 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1743 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1744
1745 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1746 le32_to_cpu(ex2->ee_block))
1747 return 0;
1748
1749 /*
1750 * To allow future support for preallocated extents to be added
1751 * as an RO_COMPAT feature, refuse to merge to extents if
1752 * this can result in the top bit of ee_len being set.
1753 */
1754 if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1755 return 0;
1756 /*
1757 * The check for IO to unwritten extent is somewhat racy as we
1758 * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1759 * dropping i_data_sem. But reserved blocks should save us in that
1760 * case.
1761 */
1762 if (ext4_ext_is_unwritten(ex1) &&
1763 (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1764 atomic_read(&EXT4_I(inode)->i_unwritten) ||
1765 (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1766 return 0;
1767#ifdef AGGRESSIVE_TEST
1768 if (ext1_ee_len >= 4)
1769 return 0;
1770#endif
1771
1772 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1773 return 1;
1774 return 0;
1775}
1776
1777/*
1778 * This function tries to merge the "ex" extent to the next extent in the tree.
1779 * It always tries to merge towards right. If you want to merge towards
1780 * left, pass "ex - 1" as argument instead of "ex".
1781 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1782 * 1 if they got merged.
1783 */
1784static int ext4_ext_try_to_merge_right(struct inode *inode,
1785 struct ext4_ext_path *path,
1786 struct ext4_extent *ex)
1787{
1788 struct ext4_extent_header *eh;
1789 unsigned int depth, len;
1790 int merge_done = 0, unwritten;
1791
1792 depth = ext_depth(inode);
1793 BUG_ON(path[depth].p_hdr == NULL);
1794 eh = path[depth].p_hdr;
1795
1796 while (ex < EXT_LAST_EXTENT(eh)) {
1797 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1798 break;
1799 /* merge with next extent! */
1800 unwritten = ext4_ext_is_unwritten(ex);
1801 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1802 + ext4_ext_get_actual_len(ex + 1));
1803 if (unwritten)
1804 ext4_ext_mark_unwritten(ex);
1805
1806 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1807 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1808 * sizeof(struct ext4_extent);
1809 memmove(ex + 1, ex + 2, len);
1810 }
1811 le16_add_cpu(&eh->eh_entries, -1);
1812 merge_done = 1;
1813 WARN_ON(eh->eh_entries == 0);
1814 if (!eh->eh_entries)
1815 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1816 }
1817
1818 return merge_done;
1819}
1820
1821/*
1822 * This function does a very simple check to see if we can collapse
1823 * an extent tree with a single extent tree leaf block into the inode.
1824 */
1825static void ext4_ext_try_to_merge_up(handle_t *handle,
1826 struct inode *inode,
1827 struct ext4_ext_path *path)
1828{
1829 size_t s;
1830 unsigned max_root = ext4_ext_space_root(inode, 0);
1831 ext4_fsblk_t blk;
1832
1833 if ((path[0].p_depth != 1) ||
1834 (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1835 (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1836 return;
1837
1838 /*
1839 * We need to modify the block allocation bitmap and the block
1840 * group descriptor to release the extent tree block. If we
1841 * can't get the journal credits, give up.
1842 */
1843 if (ext4_journal_extend(handle, 2))
1844 return;
1845
1846 /*
1847 * Copy the extent data up to the inode
1848 */
1849 blk = ext4_idx_pblock(path[0].p_idx);
1850 s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1851 sizeof(struct ext4_extent_idx);
1852 s += sizeof(struct ext4_extent_header);
1853
1854 path[1].p_maxdepth = path[0].p_maxdepth;
1855 memcpy(path[0].p_hdr, path[1].p_hdr, s);
1856 path[0].p_depth = 0;
1857 path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1858 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1859 path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1860
1861 brelse(path[1].p_bh);
1862 ext4_free_blocks(handle, inode, NULL, blk, 1,
1863 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1864}
1865
1866/*
1867 * This function tries to merge the @ex extent to neighbours in the tree.
1868 * return 1 if merge left else 0.
1869 */
1870static void ext4_ext_try_to_merge(handle_t *handle,
1871 struct inode *inode,
1872 struct ext4_ext_path *path,
1873 struct ext4_extent *ex) {
1874 struct ext4_extent_header *eh;
1875 unsigned int depth;
1876 int merge_done = 0;
1877
1878 depth = ext_depth(inode);
1879 BUG_ON(path[depth].p_hdr == NULL);
1880 eh = path[depth].p_hdr;
1881
1882 if (ex > EXT_FIRST_EXTENT(eh))
1883 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1884
1885 if (!merge_done)
1886 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1887
1888 ext4_ext_try_to_merge_up(handle, inode, path);
1889}
1890
1891/*
1892 * check if a portion of the "newext" extent overlaps with an
1893 * existing extent.
1894 *
1895 * If there is an overlap discovered, it updates the length of the newext
1896 * such that there will be no overlap, and then returns 1.
1897 * If there is no overlap found, it returns 0.
1898 */
1899static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1900 struct inode *inode,
1901 struct ext4_extent *newext,
1902 struct ext4_ext_path *path)
1903{
1904 ext4_lblk_t b1, b2;
1905 unsigned int depth, len1;
1906 unsigned int ret = 0;
1907
1908 b1 = le32_to_cpu(newext->ee_block);
1909 len1 = ext4_ext_get_actual_len(newext);
1910 depth = ext_depth(inode);
1911 if (!path[depth].p_ext)
1912 goto out;
1913 b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1914
1915 /*
1916 * get the next allocated block if the extent in the path
1917 * is before the requested block(s)
1918 */
1919 if (b2 < b1) {
1920 b2 = ext4_ext_next_allocated_block(path);
1921 if (b2 == EXT_MAX_BLOCKS)
1922 goto out;
1923 b2 = EXT4_LBLK_CMASK(sbi, b2);
1924 }
1925
1926 /* check for wrap through zero on extent logical start block*/
1927 if (b1 + len1 < b1) {
1928 len1 = EXT_MAX_BLOCKS - b1;
1929 newext->ee_len = cpu_to_le16(len1);
1930 ret = 1;
1931 }
1932
1933 /* check for overlap */
1934 if (b1 + len1 > b2) {
1935 newext->ee_len = cpu_to_le16(b2 - b1);
1936 ret = 1;
1937 }
1938out:
1939 return ret;
1940}
1941
1942/*
1943 * ext4_ext_insert_extent:
1944 * tries to merge requsted extent into the existing extent or
1945 * inserts requested extent as new one into the tree,
1946 * creating new leaf in the no-space case.
1947 */
1948int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1949 struct ext4_ext_path **ppath,
1950 struct ext4_extent *newext, int gb_flags)
1951{
1952 struct ext4_ext_path *path = *ppath;
1953 struct ext4_extent_header *eh;
1954 struct ext4_extent *ex, *fex;
1955 struct ext4_extent *nearex; /* nearest extent */
1956 struct ext4_ext_path *npath = NULL;
1957 int depth, len, err;
1958 ext4_lblk_t next;
1959 int mb_flags = 0, unwritten;
1960
1961 if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1962 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1963 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1964 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1965 return -EFSCORRUPTED;
1966 }
1967 depth = ext_depth(inode);
1968 ex = path[depth].p_ext;
1969 eh = path[depth].p_hdr;
1970 if (unlikely(path[depth].p_hdr == NULL)) {
1971 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1972 return -EFSCORRUPTED;
1973 }
1974
1975 /* try to insert block into found extent and return */
1976 if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1977
1978 /*
1979 * Try to see whether we should rather test the extent on
1980 * right from ex, or from the left of ex. This is because
1981 * ext4_find_extent() can return either extent on the
1982 * left, or on the right from the searched position. This
1983 * will make merging more effective.
1984 */
1985 if (ex < EXT_LAST_EXTENT(eh) &&
1986 (le32_to_cpu(ex->ee_block) +
1987 ext4_ext_get_actual_len(ex) <
1988 le32_to_cpu(newext->ee_block))) {
1989 ex += 1;
1990 goto prepend;
1991 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1992 (le32_to_cpu(newext->ee_block) +
1993 ext4_ext_get_actual_len(newext) <
1994 le32_to_cpu(ex->ee_block)))
1995 ex -= 1;
1996
1997 /* Try to append newex to the ex */
1998 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1999 ext_debug("append [%d]%d block to %u:[%d]%d"
2000 "(from %llu)\n",
2001 ext4_ext_is_unwritten(newext),
2002 ext4_ext_get_actual_len(newext),
2003 le32_to_cpu(ex->ee_block),
2004 ext4_ext_is_unwritten(ex),
2005 ext4_ext_get_actual_len(ex),
2006 ext4_ext_pblock(ex));
2007 err = ext4_ext_get_access(handle, inode,
2008 path + depth);
2009 if (err)
2010 return err;
2011 unwritten = ext4_ext_is_unwritten(ex);
2012 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2013 + ext4_ext_get_actual_len(newext));
2014 if (unwritten)
2015 ext4_ext_mark_unwritten(ex);
2016 eh = path[depth].p_hdr;
2017 nearex = ex;
2018 goto merge;
2019 }
2020
2021prepend:
2022 /* Try to prepend newex to the ex */
2023 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2024 ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2025 "(from %llu)\n",
2026 le32_to_cpu(newext->ee_block),
2027 ext4_ext_is_unwritten(newext),
2028 ext4_ext_get_actual_len(newext),
2029 le32_to_cpu(ex->ee_block),
2030 ext4_ext_is_unwritten(ex),
2031 ext4_ext_get_actual_len(ex),
2032 ext4_ext_pblock(ex));
2033 err = ext4_ext_get_access(handle, inode,
2034 path + depth);
2035 if (err)
2036 return err;
2037
2038 unwritten = ext4_ext_is_unwritten(ex);
2039 ex->ee_block = newext->ee_block;
2040 ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2041 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2042 + ext4_ext_get_actual_len(newext));
2043 if (unwritten)
2044 ext4_ext_mark_unwritten(ex);
2045 eh = path[depth].p_hdr;
2046 nearex = ex;
2047 goto merge;
2048 }
2049 }
2050
2051 depth = ext_depth(inode);
2052 eh = path[depth].p_hdr;
2053 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2054 goto has_space;
2055
2056 /* probably next leaf has space for us? */
2057 fex = EXT_LAST_EXTENT(eh);
2058 next = EXT_MAX_BLOCKS;
2059 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2060 next = ext4_ext_next_leaf_block(path);
2061 if (next != EXT_MAX_BLOCKS) {
2062 ext_debug("next leaf block - %u\n", next);
2063 BUG_ON(npath != NULL);
2064 npath = ext4_find_extent(inode, next, NULL, 0);
2065 if (IS_ERR(npath))
2066 return PTR_ERR(npath);
2067 BUG_ON(npath->p_depth != path->p_depth);
2068 eh = npath[depth].p_hdr;
2069 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2070 ext_debug("next leaf isn't full(%d)\n",
2071 le16_to_cpu(eh->eh_entries));
2072 path = npath;
2073 goto has_space;
2074 }
2075 ext_debug("next leaf has no free space(%d,%d)\n",
2076 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2077 }
2078
2079 /*
2080 * There is no free space in the found leaf.
2081 * We're gonna add a new leaf in the tree.
2082 */
2083 if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2084 mb_flags |= EXT4_MB_USE_RESERVED;
2085 err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2086 ppath, newext);
2087 if (err)
2088 goto cleanup;
2089 depth = ext_depth(inode);
2090 eh = path[depth].p_hdr;
2091
2092has_space:
2093 nearex = path[depth].p_ext;
2094
2095 err = ext4_ext_get_access(handle, inode, path + depth);
2096 if (err)
2097 goto cleanup;
2098
2099 if (!nearex) {
2100 /* there is no extent in this leaf, create first one */
2101 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2102 le32_to_cpu(newext->ee_block),
2103 ext4_ext_pblock(newext),
2104 ext4_ext_is_unwritten(newext),
2105 ext4_ext_get_actual_len(newext));
2106 nearex = EXT_FIRST_EXTENT(eh);
2107 } else {
2108 if (le32_to_cpu(newext->ee_block)
2109 > le32_to_cpu(nearex->ee_block)) {
2110 /* Insert after */
2111 ext_debug("insert %u:%llu:[%d]%d before: "
2112 "nearest %p\n",
2113 le32_to_cpu(newext->ee_block),
2114 ext4_ext_pblock(newext),
2115 ext4_ext_is_unwritten(newext),
2116 ext4_ext_get_actual_len(newext),
2117 nearex);
2118 nearex++;
2119 } else {
2120 /* Insert before */
2121 BUG_ON(newext->ee_block == nearex->ee_block);
2122 ext_debug("insert %u:%llu:[%d]%d after: "
2123 "nearest %p\n",
2124 le32_to_cpu(newext->ee_block),
2125 ext4_ext_pblock(newext),
2126 ext4_ext_is_unwritten(newext),
2127 ext4_ext_get_actual_len(newext),
2128 nearex);
2129 }
2130 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2131 if (len > 0) {
2132 ext_debug("insert %u:%llu:[%d]%d: "
2133 "move %d extents from 0x%p to 0x%p\n",
2134 le32_to_cpu(newext->ee_block),
2135 ext4_ext_pblock(newext),
2136 ext4_ext_is_unwritten(newext),
2137 ext4_ext_get_actual_len(newext),
2138 len, nearex, nearex + 1);
2139 memmove(nearex + 1, nearex,
2140 len * sizeof(struct ext4_extent));
2141 }
2142 }
2143
2144 le16_add_cpu(&eh->eh_entries, 1);
2145 path[depth].p_ext = nearex;
2146 nearex->ee_block = newext->ee_block;
2147 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2148 nearex->ee_len = newext->ee_len;
2149
2150merge:
2151 /* try to merge extents */
2152 if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2153 ext4_ext_try_to_merge(handle, inode, path, nearex);
2154
2155
2156 /* time to correct all indexes above */
2157 err = ext4_ext_correct_indexes(handle, inode, path);
2158 if (err)
2159 goto cleanup;
2160
2161 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2162
2163cleanup:
2164 ext4_ext_drop_refs(npath);
2165 kfree(npath);
2166 return err;
2167}
2168
2169static int ext4_fill_fiemap_extents(struct inode *inode,
2170 ext4_lblk_t block, ext4_lblk_t num,
2171 struct fiemap_extent_info *fieinfo)
2172{
2173 struct ext4_ext_path *path = NULL;
2174 struct ext4_extent *ex;
2175 struct extent_status es;
2176 ext4_lblk_t next, next_del, start = 0, end = 0;
2177 ext4_lblk_t last = block + num;
2178 int exists, depth = 0, err = 0;
2179 unsigned int flags = 0;
2180 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2181
2182 while (block < last && block != EXT_MAX_BLOCKS) {
2183 num = last - block;
2184 /* find extent for this block */
2185 down_read(&EXT4_I(inode)->i_data_sem);
2186
2187 path = ext4_find_extent(inode, block, &path, 0);
2188 if (IS_ERR(path)) {
2189 up_read(&EXT4_I(inode)->i_data_sem);
2190 err = PTR_ERR(path);
2191 path = NULL;
2192 break;
2193 }
2194
2195 depth = ext_depth(inode);
2196 if (unlikely(path[depth].p_hdr == NULL)) {
2197 up_read(&EXT4_I(inode)->i_data_sem);
2198 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2199 err = -EFSCORRUPTED;
2200 break;
2201 }
2202 ex = path[depth].p_ext;
2203 next = ext4_ext_next_allocated_block(path);
2204
2205 flags = 0;
2206 exists = 0;
2207 if (!ex) {
2208 /* there is no extent yet, so try to allocate
2209 * all requested space */
2210 start = block;
2211 end = block + num;
2212 } else if (le32_to_cpu(ex->ee_block) > block) {
2213 /* need to allocate space before found extent */
2214 start = block;
2215 end = le32_to_cpu(ex->ee_block);
2216 if (block + num < end)
2217 end = block + num;
2218 } else if (block >= le32_to_cpu(ex->ee_block)
2219 + ext4_ext_get_actual_len(ex)) {
2220 /* need to allocate space after found extent */
2221 start = block;
2222 end = block + num;
2223 if (end >= next)
2224 end = next;
2225 } else if (block >= le32_to_cpu(ex->ee_block)) {
2226 /*
2227 * some part of requested space is covered
2228 * by found extent
2229 */
2230 start = block;
2231 end = le32_to_cpu(ex->ee_block)
2232 + ext4_ext_get_actual_len(ex);
2233 if (block + num < end)
2234 end = block + num;
2235 exists = 1;
2236 } else {
2237 BUG();
2238 }
2239 BUG_ON(end <= start);
2240
2241 if (!exists) {
2242 es.es_lblk = start;
2243 es.es_len = end - start;
2244 es.es_pblk = 0;
2245 } else {
2246 es.es_lblk = le32_to_cpu(ex->ee_block);
2247 es.es_len = ext4_ext_get_actual_len(ex);
2248 es.es_pblk = ext4_ext_pblock(ex);
2249 if (ext4_ext_is_unwritten(ex))
2250 flags |= FIEMAP_EXTENT_UNWRITTEN;
2251 }
2252
2253 /*
2254 * Find delayed extent and update es accordingly. We call
2255 * it even in !exists case to find out whether es is the
2256 * last existing extent or not.
2257 */
2258 next_del = ext4_find_delayed_extent(inode, &es);
2259 if (!exists && next_del) {
2260 exists = 1;
2261 flags |= (FIEMAP_EXTENT_DELALLOC |
2262 FIEMAP_EXTENT_UNKNOWN);
2263 }
2264 up_read(&EXT4_I(inode)->i_data_sem);
2265
2266 if (unlikely(es.es_len == 0)) {
2267 EXT4_ERROR_INODE(inode, "es.es_len == 0");
2268 err = -EFSCORRUPTED;
2269 break;
2270 }
2271
2272 /*
2273 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2274 * we need to check next == EXT_MAX_BLOCKS because it is
2275 * possible that an extent is with unwritten and delayed
2276 * status due to when an extent is delayed allocated and
2277 * is allocated by fallocate status tree will track both of
2278 * them in a extent.
2279 *
2280 * So we could return a unwritten and delayed extent, and
2281 * its block is equal to 'next'.
2282 */
2283 if (next == next_del && next == EXT_MAX_BLOCKS) {
2284 flags |= FIEMAP_EXTENT_LAST;
2285 if (unlikely(next_del != EXT_MAX_BLOCKS ||
2286 next != EXT_MAX_BLOCKS)) {
2287 EXT4_ERROR_INODE(inode,
2288 "next extent == %u, next "
2289 "delalloc extent = %u",
2290 next, next_del);
2291 err = -EFSCORRUPTED;
2292 break;
2293 }
2294 }
2295
2296 if (exists) {
2297 err = fiemap_fill_next_extent(fieinfo,
2298 (__u64)es.es_lblk << blksize_bits,
2299 (__u64)es.es_pblk << blksize_bits,
2300 (__u64)es.es_len << blksize_bits,
2301 flags);
2302 if (err < 0)
2303 break;
2304 if (err == 1) {
2305 err = 0;
2306 break;
2307 }
2308 }
2309
2310 block = es.es_lblk + es.es_len;
2311 }
2312
2313 ext4_ext_drop_refs(path);
2314 kfree(path);
2315 return err;
2316}
2317
2318static int ext4_fill_es_cache_info(struct inode *inode,
2319 ext4_lblk_t block, ext4_lblk_t num,
2320 struct fiemap_extent_info *fieinfo)
2321{
2322 ext4_lblk_t next, end = block + num - 1;
2323 struct extent_status es;
2324 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2325 unsigned int flags;
2326 int err;
2327
2328 while (block <= end) {
2329 next = 0;
2330 flags = 0;
2331 if (!ext4_es_lookup_extent(inode, block, &next, &es))
2332 break;
2333 if (ext4_es_is_unwritten(&es))
2334 flags |= FIEMAP_EXTENT_UNWRITTEN;
2335 if (ext4_es_is_delayed(&es))
2336 flags |= (FIEMAP_EXTENT_DELALLOC |
2337 FIEMAP_EXTENT_UNKNOWN);
2338 if (ext4_es_is_hole(&es))
2339 flags |= EXT4_FIEMAP_EXTENT_HOLE;
2340 if (next == 0)
2341 flags |= FIEMAP_EXTENT_LAST;
2342 if (flags & (FIEMAP_EXTENT_DELALLOC|
2343 EXT4_FIEMAP_EXTENT_HOLE))
2344 es.es_pblk = 0;
2345 else
2346 es.es_pblk = ext4_es_pblock(&es);
2347 err = fiemap_fill_next_extent(fieinfo,
2348 (__u64)es.es_lblk << blksize_bits,
2349 (__u64)es.es_pblk << blksize_bits,
2350 (__u64)es.es_len << blksize_bits,
2351 flags);
2352 if (next == 0)
2353 break;
2354 block = next;
2355 if (err < 0)
2356 return err;
2357 if (err == 1)
2358 return 0;
2359 }
2360 return 0;
2361}
2362
2363
2364/*
2365 * ext4_ext_determine_hole - determine hole around given block
2366 * @inode: inode we lookup in
2367 * @path: path in extent tree to @lblk
2368 * @lblk: pointer to logical block around which we want to determine hole
2369 *
2370 * Determine hole length (and start if easily possible) around given logical
2371 * block. We don't try too hard to find the beginning of the hole but @path
2372 * actually points to extent before @lblk, we provide it.
2373 *
2374 * The function returns the length of a hole starting at @lblk. We update @lblk
2375 * to the beginning of the hole if we managed to find it.
2376 */
2377static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2378 struct ext4_ext_path *path,
2379 ext4_lblk_t *lblk)
2380{
2381 int depth = ext_depth(inode);
2382 struct ext4_extent *ex;
2383 ext4_lblk_t len;
2384
2385 ex = path[depth].p_ext;
2386 if (ex == NULL) {
2387 /* there is no extent yet, so gap is [0;-] */
2388 *lblk = 0;
2389 len = EXT_MAX_BLOCKS;
2390 } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2391 len = le32_to_cpu(ex->ee_block) - *lblk;
2392 } else if (*lblk >= le32_to_cpu(ex->ee_block)
2393 + ext4_ext_get_actual_len(ex)) {
2394 ext4_lblk_t next;
2395
2396 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2397 next = ext4_ext_next_allocated_block(path);
2398 BUG_ON(next == *lblk);
2399 len = next - *lblk;
2400 } else {
2401 BUG();
2402 }
2403 return len;
2404}
2405
2406/*
2407 * ext4_ext_put_gap_in_cache:
2408 * calculate boundaries of the gap that the requested block fits into
2409 * and cache this gap
2410 */
2411static void
2412ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2413 ext4_lblk_t hole_len)
2414{
2415 struct extent_status es;
2416
2417 ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2418 hole_start + hole_len - 1, &es);
2419 if (es.es_len) {
2420 /* There's delayed extent containing lblock? */
2421 if (es.es_lblk <= hole_start)
2422 return;
2423 hole_len = min(es.es_lblk - hole_start, hole_len);
2424 }
2425 ext_debug(" -> %u:%u\n", hole_start, hole_len);
2426 ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2427 EXTENT_STATUS_HOLE);
2428}
2429
2430/*
2431 * ext4_ext_rm_idx:
2432 * removes index from the index block.
2433 */
2434static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2435 struct ext4_ext_path *path, int depth)
2436{
2437 int err;
2438 ext4_fsblk_t leaf;
2439
2440 /* free index block */
2441 depth--;
2442 path = path + depth;
2443 leaf = ext4_idx_pblock(path->p_idx);
2444 if (unlikely(path->p_hdr->eh_entries == 0)) {
2445 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2446 return -EFSCORRUPTED;
2447 }
2448 err = ext4_ext_get_access(handle, inode, path);
2449 if (err)
2450 return err;
2451
2452 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2453 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2454 len *= sizeof(struct ext4_extent_idx);
2455 memmove(path->p_idx, path->p_idx + 1, len);
2456 }
2457
2458 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2459 err = ext4_ext_dirty(handle, inode, path);
2460 if (err)
2461 return err;
2462 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2463 trace_ext4_ext_rm_idx(inode, leaf);
2464
2465 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2466 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2467
2468 while (--depth >= 0) {
2469 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2470 break;
2471 path--;
2472 err = ext4_ext_get_access(handle, inode, path);
2473 if (err)
2474 break;
2475 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2476 err = ext4_ext_dirty(handle, inode, path);
2477 if (err)
2478 break;
2479 }
2480 return err;
2481}
2482
2483/*
2484 * ext4_ext_calc_credits_for_single_extent:
2485 * This routine returns max. credits that needed to insert an extent
2486 * to the extent tree.
2487 * When pass the actual path, the caller should calculate credits
2488 * under i_data_sem.
2489 */
2490int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2491 struct ext4_ext_path *path)
2492{
2493 if (path) {
2494 int depth = ext_depth(inode);
2495 int ret = 0;
2496
2497 /* probably there is space in leaf? */
2498 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2499 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2500
2501 /*
2502 * There are some space in the leaf tree, no
2503 * need to account for leaf block credit
2504 *
2505 * bitmaps and block group descriptor blocks
2506 * and other metadata blocks still need to be
2507 * accounted.
2508 */
2509 /* 1 bitmap, 1 block group descriptor */
2510 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2511 return ret;
2512 }
2513 }
2514
2515 return ext4_chunk_trans_blocks(inode, nrblocks);
2516}
2517
2518/*
2519 * How many index/leaf blocks need to change/allocate to add @extents extents?
2520 *
2521 * If we add a single extent, then in the worse case, each tree level
2522 * index/leaf need to be changed in case of the tree split.
2523 *
2524 * If more extents are inserted, they could cause the whole tree split more
2525 * than once, but this is really rare.
2526 */
2527int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2528{
2529 int index;
2530 int depth;
2531
2532 /* If we are converting the inline data, only one is needed here. */
2533 if (ext4_has_inline_data(inode))
2534 return 1;
2535
2536 depth = ext_depth(inode);
2537
2538 if (extents <= 1)
2539 index = depth * 2;
2540 else
2541 index = depth * 3;
2542
2543 return index;
2544}
2545
2546static inline int get_default_free_blocks_flags(struct inode *inode)
2547{
2548 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2549 ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2550 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2551 else if (ext4_should_journal_data(inode))
2552 return EXT4_FREE_BLOCKS_FORGET;
2553 return 0;
2554}
2555
2556/*
2557 * ext4_rereserve_cluster - increment the reserved cluster count when
2558 * freeing a cluster with a pending reservation
2559 *
2560 * @inode - file containing the cluster
2561 * @lblk - logical block in cluster to be reserved
2562 *
2563 * Increments the reserved cluster count and adjusts quota in a bigalloc
2564 * file system when freeing a partial cluster containing at least one
2565 * delayed and unwritten block. A partial cluster meeting that
2566 * requirement will have a pending reservation. If so, the
2567 * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2568 * defer reserved and allocated space accounting to a subsequent call
2569 * to this function.
2570 */
2571static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2572{
2573 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2574 struct ext4_inode_info *ei = EXT4_I(inode);
2575
2576 dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2577
2578 spin_lock(&ei->i_block_reservation_lock);
2579 ei->i_reserved_data_blocks++;
2580 percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2581 spin_unlock(&ei->i_block_reservation_lock);
2582
2583 percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2584 ext4_remove_pending(inode, lblk);
2585}
2586
2587static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2588 struct ext4_extent *ex,
2589 struct partial_cluster *partial,
2590 ext4_lblk_t from, ext4_lblk_t to)
2591{
2592 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2593 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2594 ext4_fsblk_t last_pblk, pblk;
2595 ext4_lblk_t num;
2596 int flags;
2597
2598 /* only extent tail removal is allowed */
2599 if (from < le32_to_cpu(ex->ee_block) ||
2600 to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2601 ext4_error(sbi->s_sb,
2602 "strange request: removal(2) %u-%u from %u:%u",
2603 from, to, le32_to_cpu(ex->ee_block), ee_len);
2604 return 0;
2605 }
2606
2607#ifdef EXTENTS_STATS
2608 spin_lock(&sbi->s_ext_stats_lock);
2609 sbi->s_ext_blocks += ee_len;
2610 sbi->s_ext_extents++;
2611 if (ee_len < sbi->s_ext_min)
2612 sbi->s_ext_min = ee_len;
2613 if (ee_len > sbi->s_ext_max)
2614 sbi->s_ext_max = ee_len;
2615 if (ext_depth(inode) > sbi->s_depth_max)
2616 sbi->s_depth_max = ext_depth(inode);
2617 spin_unlock(&sbi->s_ext_stats_lock);
2618#endif
2619
2620 trace_ext4_remove_blocks(inode, ex, from, to, partial);
2621
2622 /*
2623 * if we have a partial cluster, and it's different from the
2624 * cluster of the last block in the extent, we free it
2625 */
2626 last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2627
2628 if (partial->state != initial &&
2629 partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2630 if (partial->state == tofree) {
2631 flags = get_default_free_blocks_flags(inode);
2632 if (ext4_is_pending(inode, partial->lblk))
2633 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2634 ext4_free_blocks(handle, inode, NULL,
2635 EXT4_C2B(sbi, partial->pclu),
2636 sbi->s_cluster_ratio, flags);
2637 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2638 ext4_rereserve_cluster(inode, partial->lblk);
2639 }
2640 partial->state = initial;
2641 }
2642
2643 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2644 pblk = ext4_ext_pblock(ex) + ee_len - num;
2645
2646 /*
2647 * We free the partial cluster at the end of the extent (if any),
2648 * unless the cluster is used by another extent (partial_cluster
2649 * state is nofree). If a partial cluster exists here, it must be
2650 * shared with the last block in the extent.
2651 */
2652 flags = get_default_free_blocks_flags(inode);
2653
2654 /* partial, left end cluster aligned, right end unaligned */
2655 if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2656 (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2657 (partial->state != nofree)) {
2658 if (ext4_is_pending(inode, to))
2659 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2660 ext4_free_blocks(handle, inode, NULL,
2661 EXT4_PBLK_CMASK(sbi, last_pblk),
2662 sbi->s_cluster_ratio, flags);
2663 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2664 ext4_rereserve_cluster(inode, to);
2665 partial->state = initial;
2666 flags = get_default_free_blocks_flags(inode);
2667 }
2668
2669 flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2670
2671 /*
2672 * For bigalloc file systems, we never free a partial cluster
2673 * at the beginning of the extent. Instead, we check to see if we
2674 * need to free it on a subsequent call to ext4_remove_blocks,
2675 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2676 */
2677 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2678 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2679
2680 /* reset the partial cluster if we've freed past it */
2681 if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2682 partial->state = initial;
2683
2684 /*
2685 * If we've freed the entire extent but the beginning is not left
2686 * cluster aligned and is not marked as ineligible for freeing we
2687 * record the partial cluster at the beginning of the extent. It
2688 * wasn't freed by the preceding ext4_free_blocks() call, and we
2689 * need to look farther to the left to determine if it's to be freed
2690 * (not shared with another extent). Else, reset the partial
2691 * cluster - we're either done freeing or the beginning of the
2692 * extent is left cluster aligned.
2693 */
2694 if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2695 if (partial->state == initial) {
2696 partial->pclu = EXT4_B2C(sbi, pblk);
2697 partial->lblk = from;
2698 partial->state = tofree;
2699 }
2700 } else {
2701 partial->state = initial;
2702 }
2703
2704 return 0;
2705}
2706
2707/*
2708 * ext4_ext_rm_leaf() Removes the extents associated with the
2709 * blocks appearing between "start" and "end". Both "start"
2710 * and "end" must appear in the same extent or EIO is returned.
2711 *
2712 * @handle: The journal handle
2713 * @inode: The files inode
2714 * @path: The path to the leaf
2715 * @partial_cluster: The cluster which we'll have to free if all extents
2716 * has been released from it. However, if this value is
2717 * negative, it's a cluster just to the right of the
2718 * punched region and it must not be freed.
2719 * @start: The first block to remove
2720 * @end: The last block to remove
2721 */
2722static int
2723ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2724 struct ext4_ext_path *path,
2725 struct partial_cluster *partial,
2726 ext4_lblk_t start, ext4_lblk_t end)
2727{
2728 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2729 int err = 0, correct_index = 0;
2730 int depth = ext_depth(inode), credits;
2731 struct ext4_extent_header *eh;
2732 ext4_lblk_t a, b;
2733 unsigned num;
2734 ext4_lblk_t ex_ee_block;
2735 unsigned short ex_ee_len;
2736 unsigned unwritten = 0;
2737 struct ext4_extent *ex;
2738 ext4_fsblk_t pblk;
2739
2740 /* the header must be checked already in ext4_ext_remove_space() */
2741 ext_debug("truncate since %u in leaf to %u\n", start, end);
2742 if (!path[depth].p_hdr)
2743 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2744 eh = path[depth].p_hdr;
2745 if (unlikely(path[depth].p_hdr == NULL)) {
2746 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2747 return -EFSCORRUPTED;
2748 }
2749 /* find where to start removing */
2750 ex = path[depth].p_ext;
2751 if (!ex)
2752 ex = EXT_LAST_EXTENT(eh);
2753
2754 ex_ee_block = le32_to_cpu(ex->ee_block);
2755 ex_ee_len = ext4_ext_get_actual_len(ex);
2756
2757 trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2758
2759 while (ex >= EXT_FIRST_EXTENT(eh) &&
2760 ex_ee_block + ex_ee_len > start) {
2761
2762 if (ext4_ext_is_unwritten(ex))
2763 unwritten = 1;
2764 else
2765 unwritten = 0;
2766
2767 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2768 unwritten, ex_ee_len);
2769 path[depth].p_ext = ex;
2770
2771 a = ex_ee_block > start ? ex_ee_block : start;
2772 b = ex_ee_block+ex_ee_len - 1 < end ?
2773 ex_ee_block+ex_ee_len - 1 : end;
2774
2775 ext_debug(" border %u:%u\n", a, b);
2776
2777 /* If this extent is beyond the end of the hole, skip it */
2778 if (end < ex_ee_block) {
2779 /*
2780 * We're going to skip this extent and move to another,
2781 * so note that its first cluster is in use to avoid
2782 * freeing it when removing blocks. Eventually, the
2783 * right edge of the truncated/punched region will
2784 * be just to the left.
2785 */
2786 if (sbi->s_cluster_ratio > 1) {
2787 pblk = ext4_ext_pblock(ex);
2788 partial->pclu = EXT4_B2C(sbi, pblk);
2789 partial->state = nofree;
2790 }
2791 ex--;
2792 ex_ee_block = le32_to_cpu(ex->ee_block);
2793 ex_ee_len = ext4_ext_get_actual_len(ex);
2794 continue;
2795 } else if (b != ex_ee_block + ex_ee_len - 1) {
2796 EXT4_ERROR_INODE(inode,
2797 "can not handle truncate %u:%u "
2798 "on extent %u:%u",
2799 start, end, ex_ee_block,
2800 ex_ee_block + ex_ee_len - 1);
2801 err = -EFSCORRUPTED;
2802 goto out;
2803 } else if (a != ex_ee_block) {
2804 /* remove tail of the extent */
2805 num = a - ex_ee_block;
2806 } else {
2807 /* remove whole extent: excellent! */
2808 num = 0;
2809 }
2810 /*
2811 * 3 for leaf, sb, and inode plus 2 (bmap and group
2812 * descriptor) for each block group; assume two block
2813 * groups plus ex_ee_len/blocks_per_block_group for
2814 * the worst case
2815 */
2816 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2817 if (ex == EXT_FIRST_EXTENT(eh)) {
2818 correct_index = 1;
2819 credits += (ext_depth(inode)) + 1;
2820 }
2821 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2822
2823 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2824 if (err)
2825 goto out;
2826
2827 err = ext4_ext_get_access(handle, inode, path + depth);
2828 if (err)
2829 goto out;
2830
2831 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2832 if (err)
2833 goto out;
2834
2835 if (num == 0)
2836 /* this extent is removed; mark slot entirely unused */
2837 ext4_ext_store_pblock(ex, 0);
2838
2839 ex->ee_len = cpu_to_le16(num);
2840 /*
2841 * Do not mark unwritten if all the blocks in the
2842 * extent have been removed.
2843 */
2844 if (unwritten && num)
2845 ext4_ext_mark_unwritten(ex);
2846 /*
2847 * If the extent was completely released,
2848 * we need to remove it from the leaf
2849 */
2850 if (num == 0) {
2851 if (end != EXT_MAX_BLOCKS - 1) {
2852 /*
2853 * For hole punching, we need to scoot all the
2854 * extents up when an extent is removed so that
2855 * we dont have blank extents in the middle
2856 */
2857 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2858 sizeof(struct ext4_extent));
2859
2860 /* Now get rid of the one at the end */
2861 memset(EXT_LAST_EXTENT(eh), 0,
2862 sizeof(struct ext4_extent));
2863 }
2864 le16_add_cpu(&eh->eh_entries, -1);
2865 }
2866
2867 err = ext4_ext_dirty(handle, inode, path + depth);
2868 if (err)
2869 goto out;
2870
2871 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2872 ext4_ext_pblock(ex));
2873 ex--;
2874 ex_ee_block = le32_to_cpu(ex->ee_block);
2875 ex_ee_len = ext4_ext_get_actual_len(ex);
2876 }
2877
2878 if (correct_index && eh->eh_entries)
2879 err = ext4_ext_correct_indexes(handle, inode, path);
2880
2881 /*
2882 * If there's a partial cluster and at least one extent remains in
2883 * the leaf, free the partial cluster if it isn't shared with the
2884 * current extent. If it is shared with the current extent
2885 * we reset the partial cluster because we've reached the start of the
2886 * truncated/punched region and we're done removing blocks.
2887 */
2888 if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2889 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2890 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2891 int flags = get_default_free_blocks_flags(inode);
2892
2893 if (ext4_is_pending(inode, partial->lblk))
2894 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2895 ext4_free_blocks(handle, inode, NULL,
2896 EXT4_C2B(sbi, partial->pclu),
2897 sbi->s_cluster_ratio, flags);
2898 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2899 ext4_rereserve_cluster(inode, partial->lblk);
2900 }
2901 partial->state = initial;
2902 }
2903
2904 /* if this leaf is free, then we should
2905 * remove it from index block above */
2906 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2907 err = ext4_ext_rm_idx(handle, inode, path, depth);
2908
2909out:
2910 return err;
2911}
2912
2913/*
2914 * ext4_ext_more_to_rm:
2915 * returns 1 if current index has to be freed (even partial)
2916 */
2917static int
2918ext4_ext_more_to_rm(struct ext4_ext_path *path)
2919{
2920 BUG_ON(path->p_idx == NULL);
2921
2922 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2923 return 0;
2924
2925 /*
2926 * if truncate on deeper level happened, it wasn't partial,
2927 * so we have to consider current index for truncation
2928 */
2929 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2930 return 0;
2931 return 1;
2932}
2933
2934int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2935 ext4_lblk_t end)
2936{
2937 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2938 int depth = ext_depth(inode);
2939 struct ext4_ext_path *path = NULL;
2940 struct partial_cluster partial;
2941 handle_t *handle;
2942 int i = 0, err = 0;
2943
2944 partial.pclu = 0;
2945 partial.lblk = 0;
2946 partial.state = initial;
2947
2948 ext_debug("truncate since %u to %u\n", start, end);
2949
2950 /* probably first extent we're gonna free will be last in block */
2951 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2952 if (IS_ERR(handle))
2953 return PTR_ERR(handle);
2954
2955again:
2956 trace_ext4_ext_remove_space(inode, start, end, depth);
2957
2958 /*
2959 * Check if we are removing extents inside the extent tree. If that
2960 * is the case, we are going to punch a hole inside the extent tree
2961 * so we have to check whether we need to split the extent covering
2962 * the last block to remove so we can easily remove the part of it
2963 * in ext4_ext_rm_leaf().
2964 */
2965 if (end < EXT_MAX_BLOCKS - 1) {
2966 struct ext4_extent *ex;
2967 ext4_lblk_t ee_block, ex_end, lblk;
2968 ext4_fsblk_t pblk;
2969
2970 /* find extent for or closest extent to this block */
2971 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2972 if (IS_ERR(path)) {
2973 ext4_journal_stop(handle);
2974 return PTR_ERR(path);
2975 }
2976 depth = ext_depth(inode);
2977 /* Leaf not may not exist only if inode has no blocks at all */
2978 ex = path[depth].p_ext;
2979 if (!ex) {
2980 if (depth) {
2981 EXT4_ERROR_INODE(inode,
2982 "path[%d].p_hdr == NULL",
2983 depth);
2984 err = -EFSCORRUPTED;
2985 }
2986 goto out;
2987 }
2988
2989 ee_block = le32_to_cpu(ex->ee_block);
2990 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2991
2992 /*
2993 * See if the last block is inside the extent, if so split
2994 * the extent at 'end' block so we can easily remove the
2995 * tail of the first part of the split extent in
2996 * ext4_ext_rm_leaf().
2997 */
2998 if (end >= ee_block && end < ex_end) {
2999
3000 /*
3001 * If we're going to split the extent, note that
3002 * the cluster containing the block after 'end' is
3003 * in use to avoid freeing it when removing blocks.
3004 */
3005 if (sbi->s_cluster_ratio > 1) {
3006 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
3007 partial.pclu = EXT4_B2C(sbi, pblk);
3008 partial.state = nofree;
3009 }
3010
3011 /*
3012 * Split the extent in two so that 'end' is the last
3013 * block in the first new extent. Also we should not
3014 * fail removing space due to ENOSPC so try to use
3015 * reserved block if that happens.
3016 */
3017 err = ext4_force_split_extent_at(handle, inode, &path,
3018 end + 1, 1);
3019 if (err < 0)
3020 goto out;
3021
3022 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
3023 partial.state == initial) {
3024 /*
3025 * If we're punching, there's an extent to the right.
3026 * If the partial cluster hasn't been set, set it to
3027 * that extent's first cluster and its state to nofree
3028 * so it won't be freed should it contain blocks to be
3029 * removed. If it's already set (tofree/nofree), we're
3030 * retrying and keep the original partial cluster info
3031 * so a cluster marked tofree as a result of earlier
3032 * extent removal is not lost.
3033 */
3034 lblk = ex_end + 1;
3035 err = ext4_ext_search_right(inode, path, &lblk, &pblk,
3036 &ex);
3037 if (err)
3038 goto out;
3039 if (pblk) {
3040 partial.pclu = EXT4_B2C(sbi, pblk);
3041 partial.state = nofree;
3042 }
3043 }
3044 }
3045 /*
3046 * We start scanning from right side, freeing all the blocks
3047 * after i_size and walking into the tree depth-wise.
3048 */
3049 depth = ext_depth(inode);
3050 if (path) {
3051 int k = i = depth;
3052 while (--k > 0)
3053 path[k].p_block =
3054 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
3055 } else {
3056 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
3057 GFP_NOFS);
3058 if (path == NULL) {
3059 ext4_journal_stop(handle);
3060 return -ENOMEM;
3061 }
3062 path[0].p_maxdepth = path[0].p_depth = depth;
3063 path[0].p_hdr = ext_inode_hdr(inode);
3064 i = 0;
3065
3066 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
3067 err = -EFSCORRUPTED;
3068 goto out;
3069 }
3070 }
3071 err = 0;
3072
3073 while (i >= 0 && err == 0) {
3074 if (i == depth) {
3075 /* this is leaf block */
3076 err = ext4_ext_rm_leaf(handle, inode, path,
3077 &partial, start, end);
3078 /* root level has p_bh == NULL, brelse() eats this */
3079 brelse(path[i].p_bh);
3080 path[i].p_bh = NULL;
3081 i--;
3082 continue;
3083 }
3084
3085 /* this is index block */
3086 if (!path[i].p_hdr) {
3087 ext_debug("initialize header\n");
3088 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
3089 }
3090
3091 if (!path[i].p_idx) {
3092 /* this level hasn't been touched yet */
3093 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
3094 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
3095 ext_debug("init index ptr: hdr 0x%p, num %d\n",
3096 path[i].p_hdr,
3097 le16_to_cpu(path[i].p_hdr->eh_entries));
3098 } else {
3099 /* we were already here, see at next index */
3100 path[i].p_idx--;
3101 }
3102
3103 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
3104 i, EXT_FIRST_INDEX(path[i].p_hdr),
3105 path[i].p_idx);
3106 if (ext4_ext_more_to_rm(path + i)) {
3107 struct buffer_head *bh;
3108 /* go to the next level */
3109 ext_debug("move to level %d (block %llu)\n",
3110 i + 1, ext4_idx_pblock(path[i].p_idx));
3111 memset(path + i + 1, 0, sizeof(*path));
3112 bh = read_extent_tree_block(inode,
3113 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
3114 EXT4_EX_NOCACHE);
3115 if (IS_ERR(bh)) {
3116 /* should we reset i_size? */
3117 err = PTR_ERR(bh);
3118 break;
3119 }
3120 /* Yield here to deal with large extent trees.
3121 * Should be a no-op if we did IO above. */
3122 cond_resched();
3123 if (WARN_ON(i + 1 > depth)) {
3124 err = -EFSCORRUPTED;
3125 break;
3126 }
3127 path[i + 1].p_bh = bh;
3128
3129 /* save actual number of indexes since this
3130 * number is changed at the next iteration */
3131 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3132 i++;
3133 } else {
3134 /* we finished processing this index, go up */
3135 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3136 /* index is empty, remove it;
3137 * handle must be already prepared by the
3138 * truncatei_leaf() */
3139 err = ext4_ext_rm_idx(handle, inode, path, i);
3140 }
3141 /* root level has p_bh == NULL, brelse() eats this */
3142 brelse(path[i].p_bh);
3143 path[i].p_bh = NULL;
3144 i--;
3145 ext_debug("return to level %d\n", i);
3146 }
3147 }
3148
3149 trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3150 path->p_hdr->eh_entries);
3151
3152 /*
3153 * if there's a partial cluster and we have removed the first extent
3154 * in the file, then we also free the partial cluster, if any
3155 */
3156 if (partial.state == tofree && err == 0) {
3157 int flags = get_default_free_blocks_flags(inode);
3158
3159 if (ext4_is_pending(inode, partial.lblk))
3160 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3161 ext4_free_blocks(handle, inode, NULL,
3162 EXT4_C2B(sbi, partial.pclu),
3163 sbi->s_cluster_ratio, flags);
3164 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3165 ext4_rereserve_cluster(inode, partial.lblk);
3166 partial.state = initial;
3167 }
3168
3169 /* TODO: flexible tree reduction should be here */
3170 if (path->p_hdr->eh_entries == 0) {
3171 /*
3172 * truncate to zero freed all the tree,
3173 * so we need to correct eh_depth
3174 */
3175 err = ext4_ext_get_access(handle, inode, path);
3176 if (err == 0) {
3177 ext_inode_hdr(inode)->eh_depth = 0;
3178 ext_inode_hdr(inode)->eh_max =
3179 cpu_to_le16(ext4_ext_space_root(inode, 0));
3180 err = ext4_ext_dirty(handle, inode, path);
3181 }
3182 }
3183out:
3184 ext4_ext_drop_refs(path);
3185 kfree(path);
3186 path = NULL;
3187 if (err == -EAGAIN)
3188 goto again;
3189 ext4_journal_stop(handle);
3190
3191 return err;
3192}
3193
3194/*
3195 * called at mount time
3196 */
3197void ext4_ext_init(struct super_block *sb)
3198{
3199 /*
3200 * possible initialization would be here
3201 */
3202
3203 if (ext4_has_feature_extents(sb)) {
3204#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3205 printk(KERN_INFO "EXT4-fs: file extents enabled"
3206#ifdef AGGRESSIVE_TEST
3207 ", aggressive tests"
3208#endif
3209#ifdef CHECK_BINSEARCH
3210 ", check binsearch"
3211#endif
3212#ifdef EXTENTS_STATS
3213 ", stats"
3214#endif
3215 "\n");
3216#endif
3217#ifdef EXTENTS_STATS
3218 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3219 EXT4_SB(sb)->s_ext_min = 1 << 30;
3220 EXT4_SB(sb)->s_ext_max = 0;
3221#endif
3222 }
3223}
3224
3225/*
3226 * called at umount time
3227 */
3228void ext4_ext_release(struct super_block *sb)
3229{
3230 if (!ext4_has_feature_extents(sb))
3231 return;
3232
3233#ifdef EXTENTS_STATS
3234 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3235 struct ext4_sb_info *sbi = EXT4_SB(sb);
3236 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3237 sbi->s_ext_blocks, sbi->s_ext_extents,
3238 sbi->s_ext_blocks / sbi->s_ext_extents);
3239 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3240 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3241 }
3242#endif
3243}
3244
3245static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3246{
3247 ext4_lblk_t ee_block;
3248 ext4_fsblk_t ee_pblock;
3249 unsigned int ee_len;
3250
3251 ee_block = le32_to_cpu(ex->ee_block);
3252 ee_len = ext4_ext_get_actual_len(ex);
3253 ee_pblock = ext4_ext_pblock(ex);
3254
3255 if (ee_len == 0)
3256 return 0;
3257
3258 return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3259 EXTENT_STATUS_WRITTEN);
3260}
3261
3262/* FIXME!! we need to try to merge to left or right after zero-out */
3263static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3264{
3265 ext4_fsblk_t ee_pblock;
3266 unsigned int ee_len;
3267
3268 ee_len = ext4_ext_get_actual_len(ex);
3269 ee_pblock = ext4_ext_pblock(ex);
3270 return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3271 ee_len);
3272}
3273
3274/*
3275 * ext4_split_extent_at() splits an extent at given block.
3276 *
3277 * @handle: the journal handle
3278 * @inode: the file inode
3279 * @path: the path to the extent
3280 * @split: the logical block where the extent is splitted.
3281 * @split_flags: indicates if the extent could be zeroout if split fails, and
3282 * the states(init or unwritten) of new extents.
3283 * @flags: flags used to insert new extent to extent tree.
3284 *
3285 *
3286 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3287 * of which are deterimined by split_flag.
3288 *
3289 * There are two cases:
3290 * a> the extent are splitted into two extent.
3291 * b> split is not needed, and just mark the extent.
3292 *
3293 * return 0 on success.
3294 */
3295static int ext4_split_extent_at(handle_t *handle,
3296 struct inode *inode,
3297 struct ext4_ext_path **ppath,
3298 ext4_lblk_t split,
3299 int split_flag,
3300 int flags)
3301{
3302 struct ext4_ext_path *path = *ppath;
3303 ext4_fsblk_t newblock;
3304 ext4_lblk_t ee_block;
3305 struct ext4_extent *ex, newex, orig_ex, zero_ex;
3306 struct ext4_extent *ex2 = NULL;
3307 unsigned int ee_len, depth;
3308 int err = 0;
3309
3310 BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3311 (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3312
3313 ext_debug("ext4_split_extents_at: inode %lu, logical"
3314 "block %llu\n", inode->i_ino, (unsigned long long)split);
3315
3316 ext4_ext_show_leaf(inode, path);
3317
3318 depth = ext_depth(inode);
3319 ex = path[depth].p_ext;
3320 ee_block = le32_to_cpu(ex->ee_block);
3321 ee_len = ext4_ext_get_actual_len(ex);
3322 newblock = split - ee_block + ext4_ext_pblock(ex);
3323
3324 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3325 BUG_ON(!ext4_ext_is_unwritten(ex) &&
3326 split_flag & (EXT4_EXT_MAY_ZEROOUT |
3327 EXT4_EXT_MARK_UNWRIT1 |
3328 EXT4_EXT_MARK_UNWRIT2));
3329
3330 err = ext4_ext_get_access(handle, inode, path + depth);
3331 if (err)
3332 goto out;
3333
3334 if (split == ee_block) {
3335 /*
3336 * case b: block @split is the block that the extent begins with
3337 * then we just change the state of the extent, and splitting
3338 * is not needed.
3339 */
3340 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3341 ext4_ext_mark_unwritten(ex);
3342 else
3343 ext4_ext_mark_initialized(ex);
3344
3345 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3346 ext4_ext_try_to_merge(handle, inode, path, ex);
3347
3348 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3349 goto out;
3350 }
3351
3352 /* case a */
3353 memcpy(&orig_ex, ex, sizeof(orig_ex));
3354 ex->ee_len = cpu_to_le16(split - ee_block);
3355 if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3356 ext4_ext_mark_unwritten(ex);
3357
3358 /*
3359 * path may lead to new leaf, not to original leaf any more
3360 * after ext4_ext_insert_extent() returns,
3361 */
3362 err = ext4_ext_dirty(handle, inode, path + depth);
3363 if (err)
3364 goto fix_extent_len;
3365
3366 ex2 = &newex;
3367 ex2->ee_block = cpu_to_le32(split);
3368 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
3369 ext4_ext_store_pblock(ex2, newblock);
3370 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3371 ext4_ext_mark_unwritten(ex2);
3372
3373 err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3374 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3375 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3376 if (split_flag & EXT4_EXT_DATA_VALID1) {
3377 err = ext4_ext_zeroout(inode, ex2);
3378 zero_ex.ee_block = ex2->ee_block;
3379 zero_ex.ee_len = cpu_to_le16(
3380 ext4_ext_get_actual_len(ex2));
3381 ext4_ext_store_pblock(&zero_ex,
3382 ext4_ext_pblock(ex2));
3383 } else {
3384 err = ext4_ext_zeroout(inode, ex);
3385 zero_ex.ee_block = ex->ee_block;
3386 zero_ex.ee_len = cpu_to_le16(
3387 ext4_ext_get_actual_len(ex));
3388 ext4_ext_store_pblock(&zero_ex,
3389 ext4_ext_pblock(ex));
3390 }
3391 } else {
3392 err = ext4_ext_zeroout(inode, &orig_ex);
3393 zero_ex.ee_block = orig_ex.ee_block;
3394 zero_ex.ee_len = cpu_to_le16(
3395 ext4_ext_get_actual_len(&orig_ex));
3396 ext4_ext_store_pblock(&zero_ex,
3397 ext4_ext_pblock(&orig_ex));
3398 }
3399
3400 if (err)
3401 goto fix_extent_len;
3402 /* update the extent length and mark as initialized */
3403 ex->ee_len = cpu_to_le16(ee_len);
3404 ext4_ext_try_to_merge(handle, inode, path, ex);
3405 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3406 if (err)
3407 goto fix_extent_len;
3408
3409 /* update extent status tree */
3410 err = ext4_zeroout_es(inode, &zero_ex);
3411
3412 goto out;
3413 } else if (err)
3414 goto fix_extent_len;
3415
3416out:
3417 ext4_ext_show_leaf(inode, path);
3418 return err;
3419
3420fix_extent_len:
3421 ex->ee_len = orig_ex.ee_len;
3422 ext4_ext_dirty(handle, inode, path + path->p_depth);
3423 return err;
3424}
3425
3426/*
3427 * ext4_split_extents() splits an extent and mark extent which is covered
3428 * by @map as split_flags indicates
3429 *
3430 * It may result in splitting the extent into multiple extents (up to three)
3431 * There are three possibilities:
3432 * a> There is no split required
3433 * b> Splits in two extents: Split is happening at either end of the extent
3434 * c> Splits in three extents: Somone is splitting in middle of the extent
3435 *
3436 */
3437static int ext4_split_extent(handle_t *handle,
3438 struct inode *inode,
3439 struct ext4_ext_path **ppath,
3440 struct ext4_map_blocks *map,
3441 int split_flag,
3442 int flags)
3443{
3444 struct ext4_ext_path *path = *ppath;
3445 ext4_lblk_t ee_block;
3446 struct ext4_extent *ex;
3447 unsigned int ee_len, depth;
3448 int err = 0;
3449 int unwritten;
3450 int split_flag1, flags1;
3451 int allocated = map->m_len;
3452
3453 depth = ext_depth(inode);
3454 ex = path[depth].p_ext;
3455 ee_block = le32_to_cpu(ex->ee_block);
3456 ee_len = ext4_ext_get_actual_len(ex);
3457 unwritten = ext4_ext_is_unwritten(ex);
3458
3459 if (map->m_lblk + map->m_len < ee_block + ee_len) {
3460 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3461 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3462 if (unwritten)
3463 split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3464 EXT4_EXT_MARK_UNWRIT2;
3465 if (split_flag & EXT4_EXT_DATA_VALID2)
3466 split_flag1 |= EXT4_EXT_DATA_VALID1;
3467 err = ext4_split_extent_at(handle, inode, ppath,
3468 map->m_lblk + map->m_len, split_flag1, flags1);
3469 if (err)
3470 goto out;
3471 } else {
3472 allocated = ee_len - (map->m_lblk - ee_block);
3473 }
3474 /*
3475 * Update path is required because previous ext4_split_extent_at() may
3476 * result in split of original leaf or extent zeroout.
3477 */
3478 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3479 if (IS_ERR(path))
3480 return PTR_ERR(path);
3481 depth = ext_depth(inode);
3482 ex = path[depth].p_ext;
3483 if (!ex) {
3484 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3485 (unsigned long) map->m_lblk);
3486 return -EFSCORRUPTED;
3487 }
3488 unwritten = ext4_ext_is_unwritten(ex);
3489 split_flag1 = 0;
3490
3491 if (map->m_lblk >= ee_block) {
3492 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3493 if (unwritten) {
3494 split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3495 split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3496 EXT4_EXT_MARK_UNWRIT2);
3497 }
3498 err = ext4_split_extent_at(handle, inode, ppath,
3499 map->m_lblk, split_flag1, flags);
3500 if (err)
3501 goto out;
3502 }
3503
3504 ext4_ext_show_leaf(inode, path);
3505out:
3506 return err ? err : allocated;
3507}
3508
3509/*
3510 * This function is called by ext4_ext_map_blocks() if someone tries to write
3511 * to an unwritten extent. It may result in splitting the unwritten
3512 * extent into multiple extents (up to three - one initialized and two
3513 * unwritten).
3514 * There are three possibilities:
3515 * a> There is no split required: Entire extent should be initialized
3516 * b> Splits in two extents: Write is happening at either end of the extent
3517 * c> Splits in three extents: Somone is writing in middle of the extent
3518 *
3519 * Pre-conditions:
3520 * - The extent pointed to by 'path' is unwritten.
3521 * - The extent pointed to by 'path' contains a superset
3522 * of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3523 *
3524 * Post-conditions on success:
3525 * - the returned value is the number of blocks beyond map->l_lblk
3526 * that are allocated and initialized.
3527 * It is guaranteed to be >= map->m_len.
3528 */
3529static int ext4_ext_convert_to_initialized(handle_t *handle,
3530 struct inode *inode,
3531 struct ext4_map_blocks *map,
3532 struct ext4_ext_path **ppath,
3533 int flags)
3534{
3535 struct ext4_ext_path *path = *ppath;
3536 struct ext4_sb_info *sbi;
3537 struct ext4_extent_header *eh;
3538 struct ext4_map_blocks split_map;
3539 struct ext4_extent zero_ex1, zero_ex2;
3540 struct ext4_extent *ex, *abut_ex;
3541 ext4_lblk_t ee_block, eof_block;
3542 unsigned int ee_len, depth, map_len = map->m_len;
3543 int allocated = 0, max_zeroout = 0;
3544 int err = 0;
3545 int split_flag = EXT4_EXT_DATA_VALID2;
3546
3547 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3548 "block %llu, max_blocks %u\n", inode->i_ino,
3549 (unsigned long long)map->m_lblk, map_len);
3550
3551 sbi = EXT4_SB(inode->i_sb);
3552 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3553 inode->i_sb->s_blocksize_bits;
3554 if (eof_block < map->m_lblk + map_len)
3555 eof_block = map->m_lblk + map_len;
3556
3557 depth = ext_depth(inode);
3558 eh = path[depth].p_hdr;
3559 ex = path[depth].p_ext;
3560 ee_block = le32_to_cpu(ex->ee_block);
3561 ee_len = ext4_ext_get_actual_len(ex);
3562 zero_ex1.ee_len = 0;
3563 zero_ex2.ee_len = 0;
3564
3565 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3566
3567 /* Pre-conditions */
3568 BUG_ON(!ext4_ext_is_unwritten(ex));
3569 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3570
3571 /*
3572 * Attempt to transfer newly initialized blocks from the currently
3573 * unwritten extent to its neighbor. This is much cheaper
3574 * than an insertion followed by a merge as those involve costly
3575 * memmove() calls. Transferring to the left is the common case in
3576 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3577 * followed by append writes.
3578 *
3579 * Limitations of the current logic:
3580 * - L1: we do not deal with writes covering the whole extent.
3581 * This would require removing the extent if the transfer
3582 * is possible.
3583 * - L2: we only attempt to merge with an extent stored in the
3584 * same extent tree node.
3585 */
3586 if ((map->m_lblk == ee_block) &&
3587 /* See if we can merge left */
3588 (map_len < ee_len) && /*L1*/
3589 (ex > EXT_FIRST_EXTENT(eh))) { /*L2*/
3590 ext4_lblk_t prev_lblk;
3591 ext4_fsblk_t prev_pblk, ee_pblk;
3592 unsigned int prev_len;
3593
3594 abut_ex = ex - 1;
3595 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3596 prev_len = ext4_ext_get_actual_len(abut_ex);
3597 prev_pblk = ext4_ext_pblock(abut_ex);
3598 ee_pblk = ext4_ext_pblock(ex);
3599
3600 /*
3601 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3602 * upon those conditions:
3603 * - C1: abut_ex is initialized,
3604 * - C2: abut_ex is logically abutting ex,
3605 * - C3: abut_ex is physically abutting ex,
3606 * - C4: abut_ex can receive the additional blocks without
3607 * overflowing the (initialized) length limit.
3608 */
3609 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3610 ((prev_lblk + prev_len) == ee_block) && /*C2*/
3611 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/
3612 (prev_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3613 err = ext4_ext_get_access(handle, inode, path + depth);
3614 if (err)
3615 goto out;
3616
3617 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3618 map, ex, abut_ex);
3619
3620 /* Shift the start of ex by 'map_len' blocks */
3621 ex->ee_block = cpu_to_le32(ee_block + map_len);
3622 ext4_ext_store_pblock(ex, ee_pblk + map_len);
3623 ex->ee_len = cpu_to_le16(ee_len - map_len);
3624 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3625
3626 /* Extend abut_ex by 'map_len' blocks */
3627 abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3628
3629 /* Result: number of initialized blocks past m_lblk */
3630 allocated = map_len;
3631 }
3632 } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3633 (map_len < ee_len) && /*L1*/
3634 ex < EXT_LAST_EXTENT(eh)) { /*L2*/
3635 /* See if we can merge right */
3636 ext4_lblk_t next_lblk;
3637 ext4_fsblk_t next_pblk, ee_pblk;
3638 unsigned int next_len;
3639
3640 abut_ex = ex + 1;
3641 next_lblk = le32_to_cpu(abut_ex->ee_block);
3642 next_len = ext4_ext_get_actual_len(abut_ex);
3643 next_pblk = ext4_ext_pblock(abut_ex);
3644 ee_pblk = ext4_ext_pblock(ex);
3645
3646 /*
3647 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3648 * upon those conditions:
3649 * - C1: abut_ex is initialized,
3650 * - C2: abut_ex is logically abutting ex,
3651 * - C3: abut_ex is physically abutting ex,
3652 * - C4: abut_ex can receive the additional blocks without
3653 * overflowing the (initialized) length limit.
3654 */
3655 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3656 ((map->m_lblk + map_len) == next_lblk) && /*C2*/
3657 ((ee_pblk + ee_len) == next_pblk) && /*C3*/
3658 (next_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3659 err = ext4_ext_get_access(handle, inode, path + depth);
3660 if (err)
3661 goto out;
3662
3663 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3664 map, ex, abut_ex);
3665
3666 /* Shift the start of abut_ex by 'map_len' blocks */
3667 abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3668 ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3669 ex->ee_len = cpu_to_le16(ee_len - map_len);
3670 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3671
3672 /* Extend abut_ex by 'map_len' blocks */
3673 abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3674
3675 /* Result: number of initialized blocks past m_lblk */
3676 allocated = map_len;
3677 }
3678 }
3679 if (allocated) {
3680 /* Mark the block containing both extents as dirty */
3681 ext4_ext_dirty(handle, inode, path + depth);
3682
3683 /* Update path to point to the right extent */
3684 path[depth].p_ext = abut_ex;
3685 goto out;
3686 } else
3687 allocated = ee_len - (map->m_lblk - ee_block);
3688
3689 WARN_ON(map->m_lblk < ee_block);
3690 /*
3691 * It is safe to convert extent to initialized via explicit
3692 * zeroout only if extent is fully inside i_size or new_size.
3693 */
3694 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3695
3696 if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3697 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3698 (inode->i_sb->s_blocksize_bits - 10);
3699
3700 if (IS_ENCRYPTED(inode))
3701 max_zeroout = 0;
3702
3703 /*
3704 * five cases:
3705 * 1. split the extent into three extents.
3706 * 2. split the extent into two extents, zeroout the head of the first
3707 * extent.
3708 * 3. split the extent into two extents, zeroout the tail of the second
3709 * extent.
3710 * 4. split the extent into two extents with out zeroout.
3711 * 5. no splitting needed, just possibly zeroout the head and / or the
3712 * tail of the extent.
3713 */
3714 split_map.m_lblk = map->m_lblk;
3715 split_map.m_len = map->m_len;
3716
3717 if (max_zeroout && (allocated > split_map.m_len)) {
3718 if (allocated <= max_zeroout) {
3719 /* case 3 or 5 */
3720 zero_ex1.ee_block =
3721 cpu_to_le32(split_map.m_lblk +
3722 split_map.m_len);
3723 zero_ex1.ee_len =
3724 cpu_to_le16(allocated - split_map.m_len);
3725 ext4_ext_store_pblock(&zero_ex1,
3726 ext4_ext_pblock(ex) + split_map.m_lblk +
3727 split_map.m_len - ee_block);
3728 err = ext4_ext_zeroout(inode, &zero_ex1);
3729 if (err)
3730 goto out;
3731 split_map.m_len = allocated;
3732 }
3733 if (split_map.m_lblk - ee_block + split_map.m_len <
3734 max_zeroout) {
3735 /* case 2 or 5 */
3736 if (split_map.m_lblk != ee_block) {
3737 zero_ex2.ee_block = ex->ee_block;
3738 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3739 ee_block);
3740 ext4_ext_store_pblock(&zero_ex2,
3741 ext4_ext_pblock(ex));
3742 err = ext4_ext_zeroout(inode, &zero_ex2);
3743 if (err)
3744 goto out;
3745 }
3746
3747 split_map.m_len += split_map.m_lblk - ee_block;
3748 split_map.m_lblk = ee_block;
3749 allocated = map->m_len;
3750 }
3751 }
3752
3753 err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3754 flags);
3755 if (err > 0)
3756 err = 0;
3757out:
3758 /* If we have gotten a failure, don't zero out status tree */
3759 if (!err) {
3760 err = ext4_zeroout_es(inode, &zero_ex1);
3761 if (!err)
3762 err = ext4_zeroout_es(inode, &zero_ex2);
3763 }
3764 return err ? err : allocated;
3765}
3766
3767/*
3768 * This function is called by ext4_ext_map_blocks() from
3769 * ext4_get_blocks_dio_write() when DIO to write
3770 * to an unwritten extent.
3771 *
3772 * Writing to an unwritten extent may result in splitting the unwritten
3773 * extent into multiple initialized/unwritten extents (up to three)
3774 * There are three possibilities:
3775 * a> There is no split required: Entire extent should be unwritten
3776 * b> Splits in two extents: Write is happening at either end of the extent
3777 * c> Splits in three extents: Somone is writing in middle of the extent
3778 *
3779 * This works the same way in the case of initialized -> unwritten conversion.
3780 *
3781 * One of more index blocks maybe needed if the extent tree grow after
3782 * the unwritten extent split. To prevent ENOSPC occur at the IO
3783 * complete, we need to split the unwritten extent before DIO submit
3784 * the IO. The unwritten extent called at this time will be split
3785 * into three unwritten extent(at most). After IO complete, the part
3786 * being filled will be convert to initialized by the end_io callback function
3787 * via ext4_convert_unwritten_extents().
3788 *
3789 * Returns the size of unwritten extent to be written on success.
3790 */
3791static int ext4_split_convert_extents(handle_t *handle,
3792 struct inode *inode,
3793 struct ext4_map_blocks *map,
3794 struct ext4_ext_path **ppath,
3795 int flags)
3796{
3797 struct ext4_ext_path *path = *ppath;
3798 ext4_lblk_t eof_block;
3799 ext4_lblk_t ee_block;
3800 struct ext4_extent *ex;
3801 unsigned int ee_len;
3802 int split_flag = 0, depth;
3803
3804 ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3805 __func__, inode->i_ino,
3806 (unsigned long long)map->m_lblk, map->m_len);
3807
3808 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3809 inode->i_sb->s_blocksize_bits;
3810 if (eof_block < map->m_lblk + map->m_len)
3811 eof_block = map->m_lblk + map->m_len;
3812 /*
3813 * It is safe to convert extent to initialized via explicit
3814 * zeroout only if extent is fully insde i_size or new_size.
3815 */
3816 depth = ext_depth(inode);
3817 ex = path[depth].p_ext;
3818 ee_block = le32_to_cpu(ex->ee_block);
3819 ee_len = ext4_ext_get_actual_len(ex);
3820
3821 /* Convert to unwritten */
3822 if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3823 split_flag |= EXT4_EXT_DATA_VALID1;
3824 /* Convert to initialized */
3825 } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3826 split_flag |= ee_block + ee_len <= eof_block ?
3827 EXT4_EXT_MAY_ZEROOUT : 0;
3828 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3829 }
3830 flags |= EXT4_GET_BLOCKS_PRE_IO;
3831 return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3832}
3833
3834static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3835 struct inode *inode,
3836 struct ext4_map_blocks *map,
3837 struct ext4_ext_path **ppath)
3838{
3839 struct ext4_ext_path *path = *ppath;
3840 struct ext4_extent *ex;
3841 ext4_lblk_t ee_block;
3842 unsigned int ee_len;
3843 int depth;
3844 int err = 0;
3845
3846 depth = ext_depth(inode);
3847 ex = path[depth].p_ext;
3848 ee_block = le32_to_cpu(ex->ee_block);
3849 ee_len = ext4_ext_get_actual_len(ex);
3850
3851 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3852 "block %llu, max_blocks %u\n", inode->i_ino,
3853 (unsigned long long)ee_block, ee_len);
3854
3855 /* If extent is larger than requested it is a clear sign that we still
3856 * have some extent state machine issues left. So extent_split is still
3857 * required.
3858 * TODO: Once all related issues will be fixed this situation should be
3859 * illegal.
3860 */
3861 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3862#ifdef CONFIG_EXT4_DEBUG
3863 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3864 " len %u; IO logical block %llu, len %u",
3865 inode->i_ino, (unsigned long long)ee_block, ee_len,
3866 (unsigned long long)map->m_lblk, map->m_len);
3867#endif
3868 err = ext4_split_convert_extents(handle, inode, map, ppath,
3869 EXT4_GET_BLOCKS_CONVERT);
3870 if (err < 0)
3871 return err;
3872 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3873 if (IS_ERR(path))
3874 return PTR_ERR(path);
3875 depth = ext_depth(inode);
3876 ex = path[depth].p_ext;
3877 }
3878
3879 err = ext4_ext_get_access(handle, inode, path + depth);
3880 if (err)
3881 goto out;
3882 /* first mark the extent as initialized */
3883 ext4_ext_mark_initialized(ex);
3884
3885 /* note: ext4_ext_correct_indexes() isn't needed here because
3886 * borders are not changed
3887 */
3888 ext4_ext_try_to_merge(handle, inode, path, ex);
3889
3890 /* Mark modified extent as dirty */
3891 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3892out:
3893 ext4_ext_show_leaf(inode, path);
3894 return err;
3895}
3896
3897/*
3898 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3899 */
3900static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3901 ext4_lblk_t lblk,
3902 struct ext4_ext_path *path,
3903 unsigned int len)
3904{
3905 int i, depth;
3906 struct ext4_extent_header *eh;
3907 struct ext4_extent *last_ex;
3908
3909 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3910 return 0;
3911
3912 depth = ext_depth(inode);
3913 eh = path[depth].p_hdr;
3914
3915 /*
3916 * We're going to remove EOFBLOCKS_FL entirely in future so we
3917 * do not care for this case anymore. Simply remove the flag
3918 * if there are no extents.
3919 */
3920 if (unlikely(!eh->eh_entries))
3921 goto out;
3922 last_ex = EXT_LAST_EXTENT(eh);
3923 /*
3924 * We should clear the EOFBLOCKS_FL flag if we are writing the
3925 * last block in the last extent in the file. We test this by
3926 * first checking to see if the caller to
3927 * ext4_ext_get_blocks() was interested in the last block (or
3928 * a block beyond the last block) in the current extent. If
3929 * this turns out to be false, we can bail out from this
3930 * function immediately.
3931 */
3932 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3933 ext4_ext_get_actual_len(last_ex))
3934 return 0;
3935 /*
3936 * If the caller does appear to be planning to write at or
3937 * beyond the end of the current extent, we then test to see
3938 * if the current extent is the last extent in the file, by
3939 * checking to make sure it was reached via the rightmost node
3940 * at each level of the tree.
3941 */
3942 for (i = depth-1; i >= 0; i--)
3943 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3944 return 0;
3945out:
3946 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3947 return ext4_mark_inode_dirty(handle, inode);
3948}
3949
3950static int
3951convert_initialized_extent(handle_t *handle, struct inode *inode,
3952 struct ext4_map_blocks *map,
3953 struct ext4_ext_path **ppath,
3954 unsigned int allocated)
3955{
3956 struct ext4_ext_path *path = *ppath;
3957 struct ext4_extent *ex;
3958 ext4_lblk_t ee_block;
3959 unsigned int ee_len;
3960 int depth;
3961 int err = 0;
3962
3963 /*
3964 * Make sure that the extent is no bigger than we support with
3965 * unwritten extent
3966 */
3967 if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3968 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3969
3970 depth = ext_depth(inode);
3971 ex = path[depth].p_ext;
3972 ee_block = le32_to_cpu(ex->ee_block);
3973 ee_len = ext4_ext_get_actual_len(ex);
3974
3975 ext_debug("%s: inode %lu, logical"
3976 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3977 (unsigned long long)ee_block, ee_len);
3978
3979 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3980 err = ext4_split_convert_extents(handle, inode, map, ppath,
3981 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3982 if (err < 0)
3983 return err;
3984 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3985 if (IS_ERR(path))
3986 return PTR_ERR(path);
3987 depth = ext_depth(inode);
3988 ex = path[depth].p_ext;
3989 if (!ex) {
3990 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3991 (unsigned long) map->m_lblk);
3992 return -EFSCORRUPTED;
3993 }
3994 }
3995
3996 err = ext4_ext_get_access(handle, inode, path + depth);
3997 if (err)
3998 return err;
3999 /* first mark the extent as unwritten */
4000 ext4_ext_mark_unwritten(ex);
4001
4002 /* note: ext4_ext_correct_indexes() isn't needed here because
4003 * borders are not changed
4004 */
4005 ext4_ext_try_to_merge(handle, inode, path, ex);
4006
4007 /* Mark modified extent as dirty */
4008 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4009 if (err)
4010 return err;
4011 ext4_ext_show_leaf(inode, path);
4012
4013 ext4_update_inode_fsync_trans(handle, inode, 1);
4014 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4015 if (err)
4016 return err;
4017 map->m_flags |= EXT4_MAP_UNWRITTEN;
4018 if (allocated > map->m_len)
4019 allocated = map->m_len;
4020 map->m_len = allocated;
4021 return allocated;
4022}
4023
4024static int
4025ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4026 struct ext4_map_blocks *map,
4027 struct ext4_ext_path **ppath, int flags,
4028 unsigned int allocated, ext4_fsblk_t newblock)
4029{
4030 struct ext4_ext_path *path = *ppath;
4031 int ret = 0;
4032 int err = 0;
4033
4034 ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4035 "block %llu, max_blocks %u, flags %x, allocated %u\n",
4036 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4037 flags, allocated);
4038 ext4_ext_show_leaf(inode, path);
4039
4040 /*
4041 * When writing into unwritten space, we should not fail to
4042 * allocate metadata blocks for the new extent block if needed.
4043 */
4044 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4045
4046 trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4047 allocated, newblock);
4048
4049 /* get_block() before submit the IO, split the extent */
4050 if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4051 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4052 flags | EXT4_GET_BLOCKS_CONVERT);
4053 if (ret <= 0)
4054 goto out;
4055 map->m_flags |= EXT4_MAP_UNWRITTEN;
4056 goto out;
4057 }
4058 /* IO end_io complete, convert the filled extent to written */
4059 if (flags & EXT4_GET_BLOCKS_CONVERT) {
4060 if (flags & EXT4_GET_BLOCKS_ZERO) {
4061 if (allocated > map->m_len)
4062 allocated = map->m_len;
4063 err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4064 allocated);
4065 if (err < 0)
4066 goto out2;
4067 }
4068 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4069 ppath);
4070 if (ret >= 0) {
4071 ext4_update_inode_fsync_trans(handle, inode, 1);
4072 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4073 path, map->m_len);
4074 } else
4075 err = ret;
4076 map->m_flags |= EXT4_MAP_MAPPED;
4077 map->m_pblk = newblock;
4078 if (allocated > map->m_len)
4079 allocated = map->m_len;
4080 map->m_len = allocated;
4081 goto out2;
4082 }
4083 /* buffered IO case */
4084 /*
4085 * repeat fallocate creation request
4086 * we already have an unwritten extent
4087 */
4088 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4089 map->m_flags |= EXT4_MAP_UNWRITTEN;
4090 goto map_out;
4091 }
4092
4093 /* buffered READ or buffered write_begin() lookup */
4094 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4095 /*
4096 * We have blocks reserved already. We
4097 * return allocated blocks so that delalloc
4098 * won't do block reservation for us. But
4099 * the buffer head will be unmapped so that
4100 * a read from the block returns 0s.
4101 */
4102 map->m_flags |= EXT4_MAP_UNWRITTEN;
4103 goto out1;
4104 }
4105
4106 /* buffered write, writepage time, convert*/
4107 ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4108 if (ret >= 0)
4109 ext4_update_inode_fsync_trans(handle, inode, 1);
4110out:
4111 if (ret <= 0) {
4112 err = ret;
4113 goto out2;
4114 } else
4115 allocated = ret;
4116 map->m_flags |= EXT4_MAP_NEW;
4117 if (allocated > map->m_len)
4118 allocated = map->m_len;
4119 map->m_len = allocated;
4120
4121map_out:
4122 map->m_flags |= EXT4_MAP_MAPPED;
4123 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4124 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4125 map->m_len);
4126 if (err < 0)
4127 goto out2;
4128 }
4129out1:
4130 if (allocated > map->m_len)
4131 allocated = map->m_len;
4132 ext4_ext_show_leaf(inode, path);
4133 map->m_pblk = newblock;
4134 map->m_len = allocated;
4135out2:
4136 return err ? err : allocated;
4137}
4138
4139/*
4140 * get_implied_cluster_alloc - check to see if the requested
4141 * allocation (in the map structure) overlaps with a cluster already
4142 * allocated in an extent.
4143 * @sb The filesystem superblock structure
4144 * @map The requested lblk->pblk mapping
4145 * @ex The extent structure which might contain an implied
4146 * cluster allocation
4147 *
4148 * This function is called by ext4_ext_map_blocks() after we failed to
4149 * find blocks that were already in the inode's extent tree. Hence,
4150 * we know that the beginning of the requested region cannot overlap
4151 * the extent from the inode's extent tree. There are three cases we
4152 * want to catch. The first is this case:
4153 *
4154 * |--- cluster # N--|
4155 * |--- extent ---| |---- requested region ---|
4156 * |==========|
4157 *
4158 * The second case that we need to test for is this one:
4159 *
4160 * |--------- cluster # N ----------------|
4161 * |--- requested region --| |------- extent ----|
4162 * |=======================|
4163 *
4164 * The third case is when the requested region lies between two extents
4165 * within the same cluster:
4166 * |------------- cluster # N-------------|
4167 * |----- ex -----| |---- ex_right ----|
4168 * |------ requested region ------|
4169 * |================|
4170 *
4171 * In each of the above cases, we need to set the map->m_pblk and
4172 * map->m_len so it corresponds to the return the extent labelled as
4173 * "|====|" from cluster #N, since it is already in use for data in
4174 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to
4175 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4176 * as a new "allocated" block region. Otherwise, we will return 0 and
4177 * ext4_ext_map_blocks() will then allocate one or more new clusters
4178 * by calling ext4_mb_new_blocks().
4179 */
4180static int get_implied_cluster_alloc(struct super_block *sb,
4181 struct ext4_map_blocks *map,
4182 struct ext4_extent *ex,
4183 struct ext4_ext_path *path)
4184{
4185 struct ext4_sb_info *sbi = EXT4_SB(sb);
4186 ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4187 ext4_lblk_t ex_cluster_start, ex_cluster_end;
4188 ext4_lblk_t rr_cluster_start;
4189 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4190 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4191 unsigned short ee_len = ext4_ext_get_actual_len(ex);
4192
4193 /* The extent passed in that we are trying to match */
4194 ex_cluster_start = EXT4_B2C(sbi, ee_block);
4195 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4196
4197 /* The requested region passed into ext4_map_blocks() */
4198 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4199
4200 if ((rr_cluster_start == ex_cluster_end) ||
4201 (rr_cluster_start == ex_cluster_start)) {
4202 if (rr_cluster_start == ex_cluster_end)
4203 ee_start += ee_len - 1;
4204 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4205 map->m_len = min(map->m_len,
4206 (unsigned) sbi->s_cluster_ratio - c_offset);
4207 /*
4208 * Check for and handle this case:
4209 *
4210 * |--------- cluster # N-------------|
4211 * |------- extent ----|
4212 * |--- requested region ---|
4213 * |===========|
4214 */
4215
4216 if (map->m_lblk < ee_block)
4217 map->m_len = min(map->m_len, ee_block - map->m_lblk);
4218
4219 /*
4220 * Check for the case where there is already another allocated
4221 * block to the right of 'ex' but before the end of the cluster.
4222 *
4223 * |------------- cluster # N-------------|
4224 * |----- ex -----| |---- ex_right ----|
4225 * |------ requested region ------|
4226 * |================|
4227 */
4228 if (map->m_lblk > ee_block) {
4229 ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4230 map->m_len = min(map->m_len, next - map->m_lblk);
4231 }
4232
4233 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4234 return 1;
4235 }
4236
4237 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4238 return 0;
4239}
4240
4241
4242/*
4243 * Block allocation/map/preallocation routine for extents based files
4244 *
4245 *
4246 * Need to be called with
4247 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4248 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4249 *
4250 * return > 0, number of of blocks already mapped/allocated
4251 * if create == 0 and these are pre-allocated blocks
4252 * buffer head is unmapped
4253 * otherwise blocks are mapped
4254 *
4255 * return = 0, if plain look up failed (blocks have not been allocated)
4256 * buffer head is unmapped
4257 *
4258 * return < 0, error case.
4259 */
4260int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4261 struct ext4_map_blocks *map, int flags)
4262{
4263 struct ext4_ext_path *path = NULL;
4264 struct ext4_extent newex, *ex, *ex2;
4265 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4266 ext4_fsblk_t newblock = 0;
4267 int free_on_err = 0, err = 0, depth, ret;
4268 unsigned int allocated = 0, offset = 0;
4269 unsigned int allocated_clusters = 0;
4270 struct ext4_allocation_request ar;
4271 ext4_lblk_t cluster_offset;
4272 bool map_from_cluster = false;
4273
4274 ext_debug("blocks %u/%u requested for inode %lu\n",
4275 map->m_lblk, map->m_len, inode->i_ino);
4276 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4277
4278 /* find extent for this block */
4279 path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4280 if (IS_ERR(path)) {
4281 err = PTR_ERR(path);
4282 path = NULL;
4283 goto out2;
4284 }
4285
4286 depth = ext_depth(inode);
4287
4288 /*
4289 * consistent leaf must not be empty;
4290 * this situation is possible, though, _during_ tree modification;
4291 * this is why assert can't be put in ext4_find_extent()
4292 */
4293 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4294 EXT4_ERROR_INODE(inode, "bad extent address "
4295 "lblock: %lu, depth: %d pblock %lld",
4296 (unsigned long) map->m_lblk, depth,
4297 path[depth].p_block);
4298 err = -EFSCORRUPTED;
4299 goto out2;
4300 }
4301
4302 ex = path[depth].p_ext;
4303 if (ex) {
4304 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4305 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4306 unsigned short ee_len;
4307
4308
4309 /*
4310 * unwritten extents are treated as holes, except that
4311 * we split out initialized portions during a write.
4312 */
4313 ee_len = ext4_ext_get_actual_len(ex);
4314
4315 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4316
4317 /* if found extent covers block, simply return it */
4318 if (in_range(map->m_lblk, ee_block, ee_len)) {
4319 newblock = map->m_lblk - ee_block + ee_start;
4320 /* number of remaining blocks in the extent */
4321 allocated = ee_len - (map->m_lblk - ee_block);
4322 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4323 ee_block, ee_len, newblock);
4324
4325 /*
4326 * If the extent is initialized check whether the
4327 * caller wants to convert it to unwritten.
4328 */
4329 if ((!ext4_ext_is_unwritten(ex)) &&
4330 (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4331 allocated = convert_initialized_extent(
4332 handle, inode, map, &path,
4333 allocated);
4334 goto out2;
4335 } else if (!ext4_ext_is_unwritten(ex))
4336 goto out;
4337
4338 ret = ext4_ext_handle_unwritten_extents(
4339 handle, inode, map, &path, flags,
4340 allocated, newblock);
4341 if (ret < 0)
4342 err = ret;
4343 else
4344 allocated = ret;
4345 goto out2;
4346 }
4347 }
4348
4349 /*
4350 * requested block isn't allocated yet;
4351 * we couldn't try to create block if create flag is zero
4352 */
4353 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4354 ext4_lblk_t hole_start, hole_len;
4355
4356 hole_start = map->m_lblk;
4357 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4358 /*
4359 * put just found gap into cache to speed up
4360 * subsequent requests
4361 */
4362 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4363
4364 /* Update hole_len to reflect hole size after map->m_lblk */
4365 if (hole_start != map->m_lblk)
4366 hole_len -= map->m_lblk - hole_start;
4367 map->m_pblk = 0;
4368 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4369
4370 goto out2;
4371 }
4372
4373 /*
4374 * Okay, we need to do block allocation.
4375 */
4376 newex.ee_block = cpu_to_le32(map->m_lblk);
4377 cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4378
4379 /*
4380 * If we are doing bigalloc, check to see if the extent returned
4381 * by ext4_find_extent() implies a cluster we can use.
4382 */
4383 if (cluster_offset && ex &&
4384 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4385 ar.len = allocated = map->m_len;
4386 newblock = map->m_pblk;
4387 map_from_cluster = true;
4388 goto got_allocated_blocks;
4389 }
4390
4391 /* find neighbour allocated blocks */
4392 ar.lleft = map->m_lblk;
4393 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4394 if (err)
4395 goto out2;
4396 ar.lright = map->m_lblk;
4397 ex2 = NULL;
4398 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4399 if (err)
4400 goto out2;
4401
4402 /* Check if the extent after searching to the right implies a
4403 * cluster we can use. */
4404 if ((sbi->s_cluster_ratio > 1) && ex2 &&
4405 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4406 ar.len = allocated = map->m_len;
4407 newblock = map->m_pblk;
4408 map_from_cluster = true;
4409 goto got_allocated_blocks;
4410 }
4411
4412 /*
4413 * See if request is beyond maximum number of blocks we can have in
4414 * a single extent. For an initialized extent this limit is
4415 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4416 * EXT_UNWRITTEN_MAX_LEN.
4417 */
4418 if (map->m_len > EXT_INIT_MAX_LEN &&
4419 !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4420 map->m_len = EXT_INIT_MAX_LEN;
4421 else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4422 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4423 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4424
4425 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4426 newex.ee_len = cpu_to_le16(map->m_len);
4427 err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4428 if (err)
4429 allocated = ext4_ext_get_actual_len(&newex);
4430 else
4431 allocated = map->m_len;
4432
4433 /* allocate new block */
4434 ar.inode = inode;
4435 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4436 ar.logical = map->m_lblk;
4437 /*
4438 * We calculate the offset from the beginning of the cluster
4439 * for the logical block number, since when we allocate a
4440 * physical cluster, the physical block should start at the
4441 * same offset from the beginning of the cluster. This is
4442 * needed so that future calls to get_implied_cluster_alloc()
4443 * work correctly.
4444 */
4445 offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4446 ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4447 ar.goal -= offset;
4448 ar.logical -= offset;
4449 if (S_ISREG(inode->i_mode))
4450 ar.flags = EXT4_MB_HINT_DATA;
4451 else
4452 /* disable in-core preallocation for non-regular files */
4453 ar.flags = 0;
4454 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4455 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4456 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4457 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4458 if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4459 ar.flags |= EXT4_MB_USE_RESERVED;
4460 newblock = ext4_mb_new_blocks(handle, &ar, &err);
4461 if (!newblock)
4462 goto out2;
4463 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4464 ar.goal, newblock, allocated);
4465 free_on_err = 1;
4466 allocated_clusters = ar.len;
4467 ar.len = EXT4_C2B(sbi, ar.len) - offset;
4468 if (ar.len > allocated)
4469 ar.len = allocated;
4470
4471got_allocated_blocks:
4472 /* try to insert new extent into found leaf and return */
4473 ext4_ext_store_pblock(&newex, newblock + offset);
4474 newex.ee_len = cpu_to_le16(ar.len);
4475 /* Mark unwritten */
4476 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4477 ext4_ext_mark_unwritten(&newex);
4478 map->m_flags |= EXT4_MAP_UNWRITTEN;
4479 }
4480
4481 err = 0;
4482 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4483 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4484 path, ar.len);
4485 if (!err)
4486 err = ext4_ext_insert_extent(handle, inode, &path,
4487 &newex, flags);
4488
4489 if (err && free_on_err) {
4490 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4491 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4492 /* free data blocks we just allocated */
4493 /* not a good idea to call discard here directly,
4494 * but otherwise we'd need to call it every free() */
4495 ext4_discard_preallocations(inode);
4496 ext4_free_blocks(handle, inode, NULL, newblock,
4497 EXT4_C2B(sbi, allocated_clusters), fb_flags);
4498 goto out2;
4499 }
4500
4501 /* previous routine could use block we allocated */
4502 newblock = ext4_ext_pblock(&newex);
4503 allocated = ext4_ext_get_actual_len(&newex);
4504 if (allocated > map->m_len)
4505 allocated = map->m_len;
4506 map->m_flags |= EXT4_MAP_NEW;
4507
4508 /*
4509 * Reduce the reserved cluster count to reflect successful deferred
4510 * allocation of delayed allocated clusters or direct allocation of
4511 * clusters discovered to be delayed allocated. Once allocated, a
4512 * cluster is not included in the reserved count.
4513 */
4514 if (test_opt(inode->i_sb, DELALLOC) && !map_from_cluster) {
4515 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4516 /*
4517 * When allocating delayed allocated clusters, simply
4518 * reduce the reserved cluster count and claim quota
4519 */
4520 ext4_da_update_reserve_space(inode, allocated_clusters,
4521 1);
4522 } else {
4523 ext4_lblk_t lblk, len;
4524 unsigned int n;
4525
4526 /*
4527 * When allocating non-delayed allocated clusters
4528 * (from fallocate, filemap, DIO, or clusters
4529 * allocated when delalloc has been disabled by
4530 * ext4_nonda_switch), reduce the reserved cluster
4531 * count by the number of allocated clusters that
4532 * have previously been delayed allocated. Quota
4533 * has been claimed by ext4_mb_new_blocks() above,
4534 * so release the quota reservations made for any
4535 * previously delayed allocated clusters.
4536 */
4537 lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4538 len = allocated_clusters << sbi->s_cluster_bits;
4539 n = ext4_es_delayed_clu(inode, lblk, len);
4540 if (n > 0)
4541 ext4_da_update_reserve_space(inode, (int) n, 0);
4542 }
4543 }
4544
4545 /*
4546 * Cache the extent and update transaction to commit on fdatasync only
4547 * when it is _not_ an unwritten extent.
4548 */
4549 if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4550 ext4_update_inode_fsync_trans(handle, inode, 1);
4551 else
4552 ext4_update_inode_fsync_trans(handle, inode, 0);
4553out:
4554 if (allocated > map->m_len)
4555 allocated = map->m_len;
4556 ext4_ext_show_leaf(inode, path);
4557 map->m_flags |= EXT4_MAP_MAPPED;
4558 map->m_pblk = newblock;
4559 map->m_len = allocated;
4560out2:
4561 ext4_ext_drop_refs(path);
4562 kfree(path);
4563
4564 trace_ext4_ext_map_blocks_exit(inode, flags, map,
4565 err ? err : allocated);
4566 return err ? err : allocated;
4567}
4568
4569int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4570{
4571 struct super_block *sb = inode->i_sb;
4572 ext4_lblk_t last_block;
4573 int err = 0;
4574
4575 /*
4576 * TODO: optimization is possible here.
4577 * Probably we need not scan at all,
4578 * because page truncation is enough.
4579 */
4580
4581 /* we have to know where to truncate from in crash case */
4582 EXT4_I(inode)->i_disksize = inode->i_size;
4583 err = ext4_mark_inode_dirty(handle, inode);
4584 if (err)
4585 return err;
4586
4587 last_block = (inode->i_size + sb->s_blocksize - 1)
4588 >> EXT4_BLOCK_SIZE_BITS(sb);
4589retry:
4590 err = ext4_es_remove_extent(inode, last_block,
4591 EXT_MAX_BLOCKS - last_block);
4592 if (err == -ENOMEM) {
4593 cond_resched();
4594 congestion_wait(BLK_RW_ASYNC, HZ/50);
4595 goto retry;
4596 }
4597 if (err)
4598 return err;
4599 return ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4600}
4601
4602static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4603 ext4_lblk_t len, loff_t new_size,
4604 int flags)
4605{
4606 struct inode *inode = file_inode(file);
4607 handle_t *handle;
4608 int ret = 0;
4609 int ret2 = 0;
4610 int retries = 0;
4611 int depth = 0;
4612 struct ext4_map_blocks map;
4613 unsigned int credits;
4614 loff_t epos;
4615
4616 BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4617 map.m_lblk = offset;
4618 map.m_len = len;
4619 /*
4620 * Don't normalize the request if it can fit in one extent so
4621 * that it doesn't get unnecessarily split into multiple
4622 * extents.
4623 */
4624 if (len <= EXT_UNWRITTEN_MAX_LEN)
4625 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4626
4627 /*
4628 * credits to insert 1 extent into extent tree
4629 */
4630 credits = ext4_chunk_trans_blocks(inode, len);
4631 depth = ext_depth(inode);
4632
4633retry:
4634 while (ret >= 0 && len) {
4635 /*
4636 * Recalculate credits when extent tree depth changes.
4637 */
4638 if (depth != ext_depth(inode)) {
4639 credits = ext4_chunk_trans_blocks(inode, len);
4640 depth = ext_depth(inode);
4641 }
4642
4643 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4644 credits);
4645 if (IS_ERR(handle)) {
4646 ret = PTR_ERR(handle);
4647 break;
4648 }
4649 ret = ext4_map_blocks(handle, inode, &map, flags);
4650 if (ret <= 0) {
4651 ext4_debug("inode #%lu: block %u: len %u: "
4652 "ext4_ext_map_blocks returned %d",
4653 inode->i_ino, map.m_lblk,
4654 map.m_len, ret);
4655 ext4_mark_inode_dirty(handle, inode);
4656 ret2 = ext4_journal_stop(handle);
4657 break;
4658 }
4659 map.m_lblk += ret;
4660 map.m_len = len = len - ret;
4661 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4662 inode->i_ctime = current_time(inode);
4663 if (new_size) {
4664 if (epos > new_size)
4665 epos = new_size;
4666 if (ext4_update_inode_size(inode, epos) & 0x1)
4667 inode->i_mtime = inode->i_ctime;
4668 } else {
4669 if (epos > inode->i_size)
4670 ext4_set_inode_flag(inode,
4671 EXT4_INODE_EOFBLOCKS);
4672 }
4673 ext4_mark_inode_dirty(handle, inode);
4674 ext4_update_inode_fsync_trans(handle, inode, 1);
4675 ret2 = ext4_journal_stop(handle);
4676 if (ret2)
4677 break;
4678 }
4679 if (ret == -ENOSPC &&
4680 ext4_should_retry_alloc(inode->i_sb, &retries)) {
4681 ret = 0;
4682 goto retry;
4683 }
4684
4685 return ret > 0 ? ret2 : ret;
4686}
4687
4688static long ext4_zero_range(struct file *file, loff_t offset,
4689 loff_t len, int mode)
4690{
4691 struct inode *inode = file_inode(file);
4692 handle_t *handle = NULL;
4693 unsigned int max_blocks;
4694 loff_t new_size = 0;
4695 int ret = 0;
4696 int flags;
4697 int credits;
4698 int partial_begin, partial_end;
4699 loff_t start, end;
4700 ext4_lblk_t lblk;
4701 unsigned int blkbits = inode->i_blkbits;
4702
4703 trace_ext4_zero_range(inode, offset, len, mode);
4704
4705 if (!S_ISREG(inode->i_mode))
4706 return -EINVAL;
4707
4708 /* Call ext4_force_commit to flush all data in case of data=journal. */
4709 if (ext4_should_journal_data(inode)) {
4710 ret = ext4_force_commit(inode->i_sb);
4711 if (ret)
4712 return ret;
4713 }
4714
4715 /*
4716 * Round up offset. This is not fallocate, we neet to zero out
4717 * blocks, so convert interior block aligned part of the range to
4718 * unwritten and possibly manually zero out unaligned parts of the
4719 * range.
4720 */
4721 start = round_up(offset, 1 << blkbits);
4722 end = round_down((offset + len), 1 << blkbits);
4723
4724 if (start < offset || end > offset + len)
4725 return -EINVAL;
4726 partial_begin = offset & ((1 << blkbits) - 1);
4727 partial_end = (offset + len) & ((1 << blkbits) - 1);
4728
4729 lblk = start >> blkbits;
4730 max_blocks = (end >> blkbits);
4731 if (max_blocks < lblk)
4732 max_blocks = 0;
4733 else
4734 max_blocks -= lblk;
4735
4736 inode_lock(inode);
4737
4738 /*
4739 * Indirect files do not support unwritten extnets
4740 */
4741 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4742 ret = -EOPNOTSUPP;
4743 goto out_mutex;
4744 }
4745
4746 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4747 (offset + len > i_size_read(inode) ||
4748 offset + len > EXT4_I(inode)->i_disksize)) {
4749 new_size = offset + len;
4750 ret = inode_newsize_ok(inode, new_size);
4751 if (ret)
4752 goto out_mutex;
4753 }
4754
4755 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4756 if (mode & FALLOC_FL_KEEP_SIZE)
4757 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4758
4759 /* Wait all existing dio workers, newcomers will block on i_mutex */
4760 inode_dio_wait(inode);
4761
4762 /* Preallocate the range including the unaligned edges */
4763 if (partial_begin || partial_end) {
4764 ret = ext4_alloc_file_blocks(file,
4765 round_down(offset, 1 << blkbits) >> blkbits,
4766 (round_up((offset + len), 1 << blkbits) -
4767 round_down(offset, 1 << blkbits)) >> blkbits,
4768 new_size, flags);
4769 if (ret)
4770 goto out_mutex;
4771
4772 }
4773
4774 /* Zero range excluding the unaligned edges */
4775 if (max_blocks > 0) {
4776 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4777 EXT4_EX_NOCACHE);
4778
4779 /*
4780 * Prevent page faults from reinstantiating pages we have
4781 * released from page cache.
4782 */
4783 down_write(&EXT4_I(inode)->i_mmap_sem);
4784
4785 ret = ext4_break_layouts(inode);
4786 if (ret) {
4787 up_write(&EXT4_I(inode)->i_mmap_sem);
4788 goto out_mutex;
4789 }
4790
4791 ret = ext4_update_disksize_before_punch(inode, offset, len);
4792 if (ret) {
4793 up_write(&EXT4_I(inode)->i_mmap_sem);
4794 goto out_mutex;
4795 }
4796 /* Now release the pages and zero block aligned part of pages */
4797 truncate_pagecache_range(inode, start, end - 1);
4798 inode->i_mtime = inode->i_ctime = current_time(inode);
4799
4800 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4801 flags);
4802 up_write(&EXT4_I(inode)->i_mmap_sem);
4803 if (ret)
4804 goto out_mutex;
4805 }
4806 if (!partial_begin && !partial_end)
4807 goto out_mutex;
4808
4809 /*
4810 * In worst case we have to writeout two nonadjacent unwritten
4811 * blocks and update the inode
4812 */
4813 credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4814 if (ext4_should_journal_data(inode))
4815 credits += 2;
4816 handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4817 if (IS_ERR(handle)) {
4818 ret = PTR_ERR(handle);
4819 ext4_std_error(inode->i_sb, ret);
4820 goto out_mutex;
4821 }
4822
4823 inode->i_mtime = inode->i_ctime = current_time(inode);
4824 if (new_size) {
4825 ext4_update_inode_size(inode, new_size);
4826 } else {
4827 /*
4828 * Mark that we allocate beyond EOF so the subsequent truncate
4829 * can proceed even if the new size is the same as i_size.
4830 */
4831 if ((offset + len) > i_size_read(inode))
4832 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4833 }
4834 ext4_mark_inode_dirty(handle, inode);
4835
4836 /* Zero out partial block at the edges of the range */
4837 ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4838 if (ret >= 0)
4839 ext4_update_inode_fsync_trans(handle, inode, 1);
4840
4841 if (file->f_flags & O_SYNC)
4842 ext4_handle_sync(handle);
4843
4844 ext4_journal_stop(handle);
4845out_mutex:
4846 inode_unlock(inode);
4847 return ret;
4848}
4849
4850/*
4851 * preallocate space for a file. This implements ext4's fallocate file
4852 * operation, which gets called from sys_fallocate system call.
4853 * For block-mapped files, posix_fallocate should fall back to the method
4854 * of writing zeroes to the required new blocks (the same behavior which is
4855 * expected for file systems which do not support fallocate() system call).
4856 */
4857long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4858{
4859 struct inode *inode = file_inode(file);
4860 loff_t new_size = 0;
4861 unsigned int max_blocks;
4862 int ret = 0;
4863 int flags;
4864 ext4_lblk_t lblk;
4865 unsigned int blkbits = inode->i_blkbits;
4866
4867 /*
4868 * Encrypted inodes can't handle collapse range or insert
4869 * range since we would need to re-encrypt blocks with a
4870 * different IV or XTS tweak (which are based on the logical
4871 * block number).
4872 *
4873 * XXX It's not clear why zero range isn't working, but we'll
4874 * leave it disabled for encrypted inodes for now. This is a
4875 * bug we should fix....
4876 */
4877 if (IS_ENCRYPTED(inode) &&
4878 (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4879 FALLOC_FL_ZERO_RANGE)))
4880 return -EOPNOTSUPP;
4881
4882 /* Return error if mode is not supported */
4883 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4884 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4885 FALLOC_FL_INSERT_RANGE))
4886 return -EOPNOTSUPP;
4887
4888 if (mode & FALLOC_FL_PUNCH_HOLE)
4889 return ext4_punch_hole(inode, offset, len);
4890
4891 ret = ext4_convert_inline_data(inode);
4892 if (ret)
4893 return ret;
4894
4895 if (mode & FALLOC_FL_COLLAPSE_RANGE)
4896 return ext4_collapse_range(inode, offset, len);
4897
4898 if (mode & FALLOC_FL_INSERT_RANGE)
4899 return ext4_insert_range(inode, offset, len);
4900
4901 if (mode & FALLOC_FL_ZERO_RANGE)
4902 return ext4_zero_range(file, offset, len, mode);
4903
4904 trace_ext4_fallocate_enter(inode, offset, len, mode);
4905 lblk = offset >> blkbits;
4906
4907 max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4908 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4909 if (mode & FALLOC_FL_KEEP_SIZE)
4910 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4911
4912 inode_lock(inode);
4913
4914 /*
4915 * We only support preallocation for extent-based files only
4916 */
4917 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4918 ret = -EOPNOTSUPP;
4919 goto out;
4920 }
4921
4922 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4923 (offset + len > i_size_read(inode) ||
4924 offset + len > EXT4_I(inode)->i_disksize)) {
4925 new_size = offset + len;
4926 ret = inode_newsize_ok(inode, new_size);
4927 if (ret)
4928 goto out;
4929 }
4930
4931 /* Wait all existing dio workers, newcomers will block on i_mutex */
4932 inode_dio_wait(inode);
4933
4934 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4935 if (ret)
4936 goto out;
4937
4938 if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4939 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4940 EXT4_I(inode)->i_sync_tid);
4941 }
4942out:
4943 inode_unlock(inode);
4944 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4945 return ret;
4946}
4947
4948/*
4949 * This function convert a range of blocks to written extents
4950 * The caller of this function will pass the start offset and the size.
4951 * all unwritten extents within this range will be converted to
4952 * written extents.
4953 *
4954 * This function is called from the direct IO end io call back
4955 * function, to convert the fallocated extents after IO is completed.
4956 * Returns 0 on success.
4957 */
4958int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4959 loff_t offset, ssize_t len)
4960{
4961 unsigned int max_blocks;
4962 int ret = 0;
4963 int ret2 = 0;
4964 struct ext4_map_blocks map;
4965 unsigned int credits, blkbits = inode->i_blkbits;
4966
4967 map.m_lblk = offset >> blkbits;
4968 max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4969
4970 /*
4971 * This is somewhat ugly but the idea is clear: When transaction is
4972 * reserved, everything goes into it. Otherwise we rather start several
4973 * smaller transactions for conversion of each extent separately.
4974 */
4975 if (handle) {
4976 handle = ext4_journal_start_reserved(handle,
4977 EXT4_HT_EXT_CONVERT);
4978 if (IS_ERR(handle))
4979 return PTR_ERR(handle);
4980 credits = 0;
4981 } else {
4982 /*
4983 * credits to insert 1 extent into extent tree
4984 */
4985 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4986 }
4987 while (ret >= 0 && ret < max_blocks) {
4988 map.m_lblk += ret;
4989 map.m_len = (max_blocks -= ret);
4990 if (credits) {
4991 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4992 credits);
4993 if (IS_ERR(handle)) {
4994 ret = PTR_ERR(handle);
4995 break;
4996 }
4997 }
4998 ret = ext4_map_blocks(handle, inode, &map,
4999 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5000 if (ret <= 0)
5001 ext4_warning(inode->i_sb,
5002 "inode #%lu: block %u: len %u: "
5003 "ext4_ext_map_blocks returned %d",
5004 inode->i_ino, map.m_lblk,
5005 map.m_len, ret);
5006 ext4_mark_inode_dirty(handle, inode);
5007 if (credits)
5008 ret2 = ext4_journal_stop(handle);
5009 if (ret <= 0 || ret2)
5010 break;
5011 }
5012 if (!credits)
5013 ret2 = ext4_journal_stop(handle);
5014 return ret > 0 ? ret2 : ret;
5015}
5016
5017/*
5018 * If newes is not existing extent (newes->ec_pblk equals zero) find
5019 * delayed extent at start of newes and update newes accordingly and
5020 * return start of the next delayed extent.
5021 *
5022 * If newes is existing extent (newes->ec_pblk is not equal zero)
5023 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5024 * extent found. Leave newes unmodified.
5025 */
5026static int ext4_find_delayed_extent(struct inode *inode,
5027 struct extent_status *newes)
5028{
5029 struct extent_status es;
5030 ext4_lblk_t block, next_del;
5031
5032 if (newes->es_pblk == 0) {
5033 ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
5034 newes->es_lblk,
5035 newes->es_lblk + newes->es_len - 1,
5036 &es);
5037
5038 /*
5039 * No extent in extent-tree contains block @newes->es_pblk,
5040 * then the block may stay in 1)a hole or 2)delayed-extent.
5041 */
5042 if (es.es_len == 0)
5043 /* A hole found. */
5044 return 0;
5045
5046 if (es.es_lblk > newes->es_lblk) {
5047 /* A hole found. */
5048 newes->es_len = min(es.es_lblk - newes->es_lblk,
5049 newes->es_len);
5050 return 0;
5051 }
5052
5053 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5054 }
5055
5056 block = newes->es_lblk + newes->es_len;
5057 ext4_es_find_extent_range(inode, &ext4_es_is_delayed, block,
5058 EXT_MAX_BLOCKS, &es);
5059 if (es.es_len == 0)
5060 next_del = EXT_MAX_BLOCKS;
5061 else
5062 next_del = es.es_lblk;
5063
5064 return next_del;
5065}
5066
5067static int ext4_xattr_fiemap(struct inode *inode,
5068 struct fiemap_extent_info *fieinfo)
5069{
5070 __u64 physical = 0;
5071 __u64 length;
5072 __u32 flags = FIEMAP_EXTENT_LAST;
5073 int blockbits = inode->i_sb->s_blocksize_bits;
5074 int error = 0;
5075
5076 /* in-inode? */
5077 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5078 struct ext4_iloc iloc;
5079 int offset; /* offset of xattr in inode */
5080
5081 error = ext4_get_inode_loc(inode, &iloc);
5082 if (error)
5083 return error;
5084 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5085 offset = EXT4_GOOD_OLD_INODE_SIZE +
5086 EXT4_I(inode)->i_extra_isize;
5087 physical += offset;
5088 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5089 flags |= FIEMAP_EXTENT_DATA_INLINE;
5090 brelse(iloc.bh);
5091 } else { /* external block */
5092 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5093 length = inode->i_sb->s_blocksize;
5094 }
5095
5096 if (physical)
5097 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5098 length, flags);
5099 return (error < 0 ? error : 0);
5100}
5101
5102static int _ext4_fiemap(struct inode *inode,
5103 struct fiemap_extent_info *fieinfo,
5104 __u64 start, __u64 len,
5105 int (*fill)(struct inode *, ext4_lblk_t,
5106 ext4_lblk_t,
5107 struct fiemap_extent_info *))
5108{
5109 ext4_lblk_t start_blk;
5110 u32 ext4_fiemap_flags = FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR;
5111
5112 int error = 0;
5113
5114 if (ext4_has_inline_data(inode)) {
5115 int has_inline = 1;
5116
5117 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5118 start, len);
5119
5120 if (has_inline)
5121 return error;
5122 }
5123
5124 if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5125 error = ext4_ext_precache(inode);
5126 if (error)
5127 return error;
5128 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5129 }
5130
5131 /* fallback to generic here if not in extents fmt */
5132 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
5133 fill == ext4_fill_fiemap_extents)
5134 return generic_block_fiemap(inode, fieinfo, start, len,
5135 ext4_get_block);
5136
5137 if (fill == ext4_fill_es_cache_info)
5138 ext4_fiemap_flags &= FIEMAP_FLAG_XATTR;
5139 if (fiemap_check_flags(fieinfo, ext4_fiemap_flags))
5140 return -EBADR;
5141
5142 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5143 error = ext4_xattr_fiemap(inode, fieinfo);
5144 } else {
5145 ext4_lblk_t len_blks;
5146 __u64 last_blk;
5147
5148 start_blk = start >> inode->i_sb->s_blocksize_bits;
5149 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5150 if (last_blk >= EXT_MAX_BLOCKS)
5151 last_blk = EXT_MAX_BLOCKS-1;
5152 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5153
5154 /*
5155 * Walk the extent tree gathering extent information
5156 * and pushing extents back to the user.
5157 */
5158 error = fill(inode, start_blk, len_blks, fieinfo);
5159 }
5160 return error;
5161}
5162
5163int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5164 __u64 start, __u64 len)
5165{
5166 return _ext4_fiemap(inode, fieinfo, start, len,
5167 ext4_fill_fiemap_extents);
5168}
5169
5170int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
5171 __u64 start, __u64 len)
5172{
5173 if (ext4_has_inline_data(inode)) {
5174 int has_inline;
5175
5176 down_read(&EXT4_I(inode)->xattr_sem);
5177 has_inline = ext4_has_inline_data(inode);
5178 up_read(&EXT4_I(inode)->xattr_sem);
5179 if (has_inline)
5180 return 0;
5181 }
5182
5183 return _ext4_fiemap(inode, fieinfo, start, len,
5184 ext4_fill_es_cache_info);
5185}
5186
5187
5188/*
5189 * ext4_access_path:
5190 * Function to access the path buffer for marking it dirty.
5191 * It also checks if there are sufficient credits left in the journal handle
5192 * to update path.
5193 */
5194static int
5195ext4_access_path(handle_t *handle, struct inode *inode,
5196 struct ext4_ext_path *path)
5197{
5198 int credits, err;
5199
5200 if (!ext4_handle_valid(handle))
5201 return 0;
5202
5203 /*
5204 * Check if need to extend journal credits
5205 * 3 for leaf, sb, and inode plus 2 (bmap and group
5206 * descriptor) for each block group; assume two block
5207 * groups
5208 */
5209 if (handle->h_buffer_credits < 7) {
5210 credits = ext4_writepage_trans_blocks(inode);
5211 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5212 /* EAGAIN is success */
5213 if (err && err != -EAGAIN)
5214 return err;
5215 }
5216
5217 err = ext4_ext_get_access(handle, inode, path);
5218 return err;
5219}
5220
5221/*
5222 * ext4_ext_shift_path_extents:
5223 * Shift the extents of a path structure lying between path[depth].p_ext
5224 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5225 * if it is right shift or left shift operation.
5226 */
5227static int
5228ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5229 struct inode *inode, handle_t *handle,
5230 enum SHIFT_DIRECTION SHIFT)
5231{
5232 int depth, err = 0;
5233 struct ext4_extent *ex_start, *ex_last;
5234 bool update = 0;
5235 depth = path->p_depth;
5236
5237 while (depth >= 0) {
5238 if (depth == path->p_depth) {
5239 ex_start = path[depth].p_ext;
5240 if (!ex_start)
5241 return -EFSCORRUPTED;
5242
5243 ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5244
5245 err = ext4_access_path(handle, inode, path + depth);
5246 if (err)
5247 goto out;
5248
5249 if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5250 update = 1;
5251
5252 while (ex_start <= ex_last) {
5253 if (SHIFT == SHIFT_LEFT) {
5254 le32_add_cpu(&ex_start->ee_block,
5255 -shift);
5256 /* Try to merge to the left. */
5257 if ((ex_start >
5258 EXT_FIRST_EXTENT(path[depth].p_hdr))
5259 &&
5260 ext4_ext_try_to_merge_right(inode,
5261 path, ex_start - 1))
5262 ex_last--;
5263 else
5264 ex_start++;
5265 } else {
5266 le32_add_cpu(&ex_last->ee_block, shift);
5267 ext4_ext_try_to_merge_right(inode, path,
5268 ex_last);
5269 ex_last--;
5270 }
5271 }
5272 err = ext4_ext_dirty(handle, inode, path + depth);
5273 if (err)
5274 goto out;
5275
5276 if (--depth < 0 || !update)
5277 break;
5278 }
5279
5280 /* Update index too */
5281 err = ext4_access_path(handle, inode, path + depth);
5282 if (err)
5283 goto out;
5284
5285 if (SHIFT == SHIFT_LEFT)
5286 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5287 else
5288 le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5289 err = ext4_ext_dirty(handle, inode, path + depth);
5290 if (err)
5291 goto out;
5292
5293 /* we are done if current index is not a starting index */
5294 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5295 break;
5296
5297 depth--;
5298 }
5299
5300out:
5301 return err;
5302}
5303
5304/*
5305 * ext4_ext_shift_extents:
5306 * All the extents which lies in the range from @start to the last allocated
5307 * block for the @inode are shifted either towards left or right (depending
5308 * upon @SHIFT) by @shift blocks.
5309 * On success, 0 is returned, error otherwise.
5310 */
5311static int
5312ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5313 ext4_lblk_t start, ext4_lblk_t shift,
5314 enum SHIFT_DIRECTION SHIFT)
5315{
5316 struct ext4_ext_path *path;
5317 int ret = 0, depth;
5318 struct ext4_extent *extent;
5319 ext4_lblk_t stop, *iterator, ex_start, ex_end;
5320
5321 /* Let path point to the last extent */
5322 path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5323 EXT4_EX_NOCACHE);
5324 if (IS_ERR(path))
5325 return PTR_ERR(path);
5326
5327 depth = path->p_depth;
5328 extent = path[depth].p_ext;
5329 if (!extent)
5330 goto out;
5331
5332 stop = le32_to_cpu(extent->ee_block);
5333
5334 /*
5335 * For left shifts, make sure the hole on the left is big enough to
5336 * accommodate the shift. For right shifts, make sure the last extent
5337 * won't be shifted beyond EXT_MAX_BLOCKS.
5338 */
5339 if (SHIFT == SHIFT_LEFT) {
5340 path = ext4_find_extent(inode, start - 1, &path,
5341 EXT4_EX_NOCACHE);
5342 if (IS_ERR(path))
5343 return PTR_ERR(path);
5344 depth = path->p_depth;
5345 extent = path[depth].p_ext;
5346 if (extent) {
5347 ex_start = le32_to_cpu(extent->ee_block);
5348 ex_end = le32_to_cpu(extent->ee_block) +
5349 ext4_ext_get_actual_len(extent);
5350 } else {
5351 ex_start = 0;
5352 ex_end = 0;
5353 }
5354
5355 if ((start == ex_start && shift > ex_start) ||
5356 (shift > start - ex_end)) {
5357 ret = -EINVAL;
5358 goto out;
5359 }
5360 } else {
5361 if (shift > EXT_MAX_BLOCKS -
5362 (stop + ext4_ext_get_actual_len(extent))) {
5363 ret = -EINVAL;
5364 goto out;
5365 }
5366 }
5367
5368 /*
5369 * In case of left shift, iterator points to start and it is increased
5370 * till we reach stop. In case of right shift, iterator points to stop
5371 * and it is decreased till we reach start.
5372 */
5373 if (SHIFT == SHIFT_LEFT)
5374 iterator = &start;
5375 else
5376 iterator = &stop;
5377
5378 /*
5379 * Its safe to start updating extents. Start and stop are unsigned, so
5380 * in case of right shift if extent with 0 block is reached, iterator
5381 * becomes NULL to indicate the end of the loop.
5382 */
5383 while (iterator && start <= stop) {
5384 path = ext4_find_extent(inode, *iterator, &path,
5385 EXT4_EX_NOCACHE);
5386 if (IS_ERR(path))
5387 return PTR_ERR(path);
5388 depth = path->p_depth;
5389 extent = path[depth].p_ext;
5390 if (!extent) {
5391 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5392 (unsigned long) *iterator);
5393 return -EFSCORRUPTED;
5394 }
5395 if (SHIFT == SHIFT_LEFT && *iterator >
5396 le32_to_cpu(extent->ee_block)) {
5397 /* Hole, move to the next extent */
5398 if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5399 path[depth].p_ext++;
5400 } else {
5401 *iterator = ext4_ext_next_allocated_block(path);
5402 continue;
5403 }
5404 }
5405
5406 if (SHIFT == SHIFT_LEFT) {
5407 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5408 *iterator = le32_to_cpu(extent->ee_block) +
5409 ext4_ext_get_actual_len(extent);
5410 } else {
5411 extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5412 if (le32_to_cpu(extent->ee_block) > 0)
5413 *iterator = le32_to_cpu(extent->ee_block) - 1;
5414 else
5415 /* Beginning is reached, end of the loop */
5416 iterator = NULL;
5417 /* Update path extent in case we need to stop */
5418 while (le32_to_cpu(extent->ee_block) < start)
5419 extent++;
5420 path[depth].p_ext = extent;
5421 }
5422 ret = ext4_ext_shift_path_extents(path, shift, inode,
5423 handle, SHIFT);
5424 if (ret)
5425 break;
5426 }
5427out:
5428 ext4_ext_drop_refs(path);
5429 kfree(path);
5430 return ret;
5431}
5432
5433/*
5434 * ext4_collapse_range:
5435 * This implements the fallocate's collapse range functionality for ext4
5436 * Returns: 0 and non-zero on error.
5437 */
5438int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5439{
5440 struct super_block *sb = inode->i_sb;
5441 ext4_lblk_t punch_start, punch_stop;
5442 handle_t *handle;
5443 unsigned int credits;
5444 loff_t new_size, ioffset;
5445 int ret;
5446
5447 /*
5448 * We need to test this early because xfstests assumes that a
5449 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5450 * system does not support collapse range.
5451 */
5452 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5453 return -EOPNOTSUPP;
5454
5455 /* Collapse range works only on fs block size aligned offsets. */
5456 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5457 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5458 return -EINVAL;
5459
5460 if (!S_ISREG(inode->i_mode))
5461 return -EINVAL;
5462
5463 trace_ext4_collapse_range(inode, offset, len);
5464
5465 punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5466 punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5467
5468 /* Call ext4_force_commit to flush all data in case of data=journal. */
5469 if (ext4_should_journal_data(inode)) {
5470 ret = ext4_force_commit(inode->i_sb);
5471 if (ret)
5472 return ret;
5473 }
5474
5475 inode_lock(inode);
5476 /*
5477 * There is no need to overlap collapse range with EOF, in which case
5478 * it is effectively a truncate operation
5479 */
5480 if (offset + len >= i_size_read(inode)) {
5481 ret = -EINVAL;
5482 goto out_mutex;
5483 }
5484
5485 /* Currently just for extent based files */
5486 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5487 ret = -EOPNOTSUPP;
5488 goto out_mutex;
5489 }
5490
5491 /* Wait for existing dio to complete */
5492 inode_dio_wait(inode);
5493
5494 /*
5495 * Prevent page faults from reinstantiating pages we have released from
5496 * page cache.
5497 */
5498 down_write(&EXT4_I(inode)->i_mmap_sem);
5499
5500 ret = ext4_break_layouts(inode);
5501 if (ret)
5502 goto out_mmap;
5503
5504 /*
5505 * Need to round down offset to be aligned with page size boundary
5506 * for page size > block size.
5507 */
5508 ioffset = round_down(offset, PAGE_SIZE);
5509 /*
5510 * Write tail of the last page before removed range since it will get
5511 * removed from the page cache below.
5512 */
5513 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5514 if (ret)
5515 goto out_mmap;
5516 /*
5517 * Write data that will be shifted to preserve them when discarding
5518 * page cache below. We are also protected from pages becoming dirty
5519 * by i_mmap_sem.
5520 */
5521 ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5522 LLONG_MAX);
5523 if (ret)
5524 goto out_mmap;
5525 truncate_pagecache(inode, ioffset);
5526
5527 credits = ext4_writepage_trans_blocks(inode);
5528 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5529 if (IS_ERR(handle)) {
5530 ret = PTR_ERR(handle);
5531 goto out_mmap;
5532 }
5533
5534 down_write(&EXT4_I(inode)->i_data_sem);
5535 ext4_discard_preallocations(inode);
5536
5537 ret = ext4_es_remove_extent(inode, punch_start,
5538 EXT_MAX_BLOCKS - punch_start);
5539 if (ret) {
5540 up_write(&EXT4_I(inode)->i_data_sem);
5541 goto out_stop;
5542 }
5543
5544 ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5545 if (ret) {
5546 up_write(&EXT4_I(inode)->i_data_sem);
5547 goto out_stop;
5548 }
5549 ext4_discard_preallocations(inode);
5550
5551 ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5552 punch_stop - punch_start, SHIFT_LEFT);
5553 if (ret) {
5554 up_write(&EXT4_I(inode)->i_data_sem);
5555 goto out_stop;
5556 }
5557
5558 new_size = i_size_read(inode) - len;
5559 i_size_write(inode, new_size);
5560 EXT4_I(inode)->i_disksize = new_size;
5561
5562 up_write(&EXT4_I(inode)->i_data_sem);
5563 if (IS_SYNC(inode))
5564 ext4_handle_sync(handle);
5565 inode->i_mtime = inode->i_ctime = current_time(inode);
5566 ext4_mark_inode_dirty(handle, inode);
5567 ext4_update_inode_fsync_trans(handle, inode, 1);
5568
5569out_stop:
5570 ext4_journal_stop(handle);
5571out_mmap:
5572 up_write(&EXT4_I(inode)->i_mmap_sem);
5573out_mutex:
5574 inode_unlock(inode);
5575 return ret;
5576}
5577
5578/*
5579 * ext4_insert_range:
5580 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5581 * The data blocks starting from @offset to the EOF are shifted by @len
5582 * towards right to create a hole in the @inode. Inode size is increased
5583 * by len bytes.
5584 * Returns 0 on success, error otherwise.
5585 */
5586int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5587{
5588 struct super_block *sb = inode->i_sb;
5589 handle_t *handle;
5590 struct ext4_ext_path *path;
5591 struct ext4_extent *extent;
5592 ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5593 unsigned int credits, ee_len;
5594 int ret = 0, depth, split_flag = 0;
5595 loff_t ioffset;
5596
5597 /*
5598 * We need to test this early because xfstests assumes that an
5599 * insert range of (0, 1) will return EOPNOTSUPP if the file
5600 * system does not support insert range.
5601 */
5602 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5603 return -EOPNOTSUPP;
5604
5605 /* Insert range works only on fs block size aligned offsets. */
5606 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5607 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5608 return -EINVAL;
5609
5610 if (!S_ISREG(inode->i_mode))
5611 return -EOPNOTSUPP;
5612
5613 trace_ext4_insert_range(inode, offset, len);
5614
5615 offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5616 len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5617
5618 /* Call ext4_force_commit to flush all data in case of data=journal */
5619 if (ext4_should_journal_data(inode)) {
5620 ret = ext4_force_commit(inode->i_sb);
5621 if (ret)
5622 return ret;
5623 }
5624
5625 inode_lock(inode);
5626 /* Currently just for extent based files */
5627 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5628 ret = -EOPNOTSUPP;
5629 goto out_mutex;
5630 }
5631
5632 /* Check for wrap through zero */
5633 if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5634 ret = -EFBIG;
5635 goto out_mutex;
5636 }
5637
5638 /* Offset should be less than i_size */
5639 if (offset >= i_size_read(inode)) {
5640 ret = -EINVAL;
5641 goto out_mutex;
5642 }
5643
5644 /* Wait for existing dio to complete */
5645 inode_dio_wait(inode);
5646
5647 /*
5648 * Prevent page faults from reinstantiating pages we have released from
5649 * page cache.
5650 */
5651 down_write(&EXT4_I(inode)->i_mmap_sem);
5652
5653 ret = ext4_break_layouts(inode);
5654 if (ret)
5655 goto out_mmap;
5656
5657 /*
5658 * Need to round down to align start offset to page size boundary
5659 * for page size > block size.
5660 */
5661 ioffset = round_down(offset, PAGE_SIZE);
5662 /* Write out all dirty pages */
5663 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5664 LLONG_MAX);
5665 if (ret)
5666 goto out_mmap;
5667 truncate_pagecache(inode, ioffset);
5668
5669 credits = ext4_writepage_trans_blocks(inode);
5670 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5671 if (IS_ERR(handle)) {
5672 ret = PTR_ERR(handle);
5673 goto out_mmap;
5674 }
5675
5676 /* Expand file to avoid data loss if there is error while shifting */
5677 inode->i_size += len;
5678 EXT4_I(inode)->i_disksize += len;
5679 inode->i_mtime = inode->i_ctime = current_time(inode);
5680 ret = ext4_mark_inode_dirty(handle, inode);
5681 if (ret)
5682 goto out_stop;
5683
5684 down_write(&EXT4_I(inode)->i_data_sem);
5685 ext4_discard_preallocations(inode);
5686
5687 path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5688 if (IS_ERR(path)) {
5689 up_write(&EXT4_I(inode)->i_data_sem);
5690 goto out_stop;
5691 }
5692
5693 depth = ext_depth(inode);
5694 extent = path[depth].p_ext;
5695 if (extent) {
5696 ee_start_lblk = le32_to_cpu(extent->ee_block);
5697 ee_len = ext4_ext_get_actual_len(extent);
5698
5699 /*
5700 * If offset_lblk is not the starting block of extent, split
5701 * the extent @offset_lblk
5702 */
5703 if ((offset_lblk > ee_start_lblk) &&
5704 (offset_lblk < (ee_start_lblk + ee_len))) {
5705 if (ext4_ext_is_unwritten(extent))
5706 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5707 EXT4_EXT_MARK_UNWRIT2;
5708 ret = ext4_split_extent_at(handle, inode, &path,
5709 offset_lblk, split_flag,
5710 EXT4_EX_NOCACHE |
5711 EXT4_GET_BLOCKS_PRE_IO |
5712 EXT4_GET_BLOCKS_METADATA_NOFAIL);
5713 }
5714
5715 ext4_ext_drop_refs(path);
5716 kfree(path);
5717 if (ret < 0) {
5718 up_write(&EXT4_I(inode)->i_data_sem);
5719 goto out_stop;
5720 }
5721 } else {
5722 ext4_ext_drop_refs(path);
5723 kfree(path);
5724 }
5725
5726 ret = ext4_es_remove_extent(inode, offset_lblk,
5727 EXT_MAX_BLOCKS - offset_lblk);
5728 if (ret) {
5729 up_write(&EXT4_I(inode)->i_data_sem);
5730 goto out_stop;
5731 }
5732
5733 /*
5734 * if offset_lblk lies in a hole which is at start of file, use
5735 * ee_start_lblk to shift extents
5736 */
5737 ret = ext4_ext_shift_extents(inode, handle,
5738 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5739 len_lblk, SHIFT_RIGHT);
5740
5741 up_write(&EXT4_I(inode)->i_data_sem);
5742 if (IS_SYNC(inode))
5743 ext4_handle_sync(handle);
5744 if (ret >= 0)
5745 ext4_update_inode_fsync_trans(handle, inode, 1);
5746
5747out_stop:
5748 ext4_journal_stop(handle);
5749out_mmap:
5750 up_write(&EXT4_I(inode)->i_mmap_sem);
5751out_mutex:
5752 inode_unlock(inode);
5753 return ret;
5754}
5755
5756/**
5757 * ext4_swap_extents() - Swap extents between two inodes
5758 * @handle: handle for this transaction
5759 * @inode1: First inode
5760 * @inode2: Second inode
5761 * @lblk1: Start block for first inode
5762 * @lblk2: Start block for second inode
5763 * @count: Number of blocks to swap
5764 * @unwritten: Mark second inode's extents as unwritten after swap
5765 * @erp: Pointer to save error value
5766 *
5767 * This helper routine does exactly what is promise "swap extents". All other
5768 * stuff such as page-cache locking consistency, bh mapping consistency or
5769 * extent's data copying must be performed by caller.
5770 * Locking:
5771 * i_mutex is held for both inodes
5772 * i_data_sem is locked for write for both inodes
5773 * Assumptions:
5774 * All pages from requested range are locked for both inodes
5775 */
5776int
5777ext4_swap_extents(handle_t *handle, struct inode *inode1,
5778 struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5779 ext4_lblk_t count, int unwritten, int *erp)
5780{
5781 struct ext4_ext_path *path1 = NULL;
5782 struct ext4_ext_path *path2 = NULL;
5783 int replaced_count = 0;
5784
5785 BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5786 BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5787 BUG_ON(!inode_is_locked(inode1));
5788 BUG_ON(!inode_is_locked(inode2));
5789
5790 *erp = ext4_es_remove_extent(inode1, lblk1, count);
5791 if (unlikely(*erp))
5792 return 0;
5793 *erp = ext4_es_remove_extent(inode2, lblk2, count);
5794 if (unlikely(*erp))
5795 return 0;
5796
5797 while (count) {
5798 struct ext4_extent *ex1, *ex2, tmp_ex;
5799 ext4_lblk_t e1_blk, e2_blk;
5800 int e1_len, e2_len, len;
5801 int split = 0;
5802
5803 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5804 if (IS_ERR(path1)) {
5805 *erp = PTR_ERR(path1);
5806 path1 = NULL;
5807 finish:
5808 count = 0;
5809 goto repeat;
5810 }
5811 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5812 if (IS_ERR(path2)) {
5813 *erp = PTR_ERR(path2);
5814 path2 = NULL;
5815 goto finish;
5816 }
5817 ex1 = path1[path1->p_depth].p_ext;
5818 ex2 = path2[path2->p_depth].p_ext;
5819 /* Do we have somthing to swap ? */
5820 if (unlikely(!ex2 || !ex1))
5821 goto finish;
5822
5823 e1_blk = le32_to_cpu(ex1->ee_block);
5824 e2_blk = le32_to_cpu(ex2->ee_block);
5825 e1_len = ext4_ext_get_actual_len(ex1);
5826 e2_len = ext4_ext_get_actual_len(ex2);
5827
5828 /* Hole handling */
5829 if (!in_range(lblk1, e1_blk, e1_len) ||
5830 !in_range(lblk2, e2_blk, e2_len)) {
5831 ext4_lblk_t next1, next2;
5832
5833 /* if hole after extent, then go to next extent */
5834 next1 = ext4_ext_next_allocated_block(path1);
5835 next2 = ext4_ext_next_allocated_block(path2);
5836 /* If hole before extent, then shift to that extent */
5837 if (e1_blk > lblk1)
5838 next1 = e1_blk;
5839 if (e2_blk > lblk2)
5840 next2 = e2_blk;
5841 /* Do we have something to swap */
5842 if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5843 goto finish;
5844 /* Move to the rightest boundary */
5845 len = next1 - lblk1;
5846 if (len < next2 - lblk2)
5847 len = next2 - lblk2;
5848 if (len > count)
5849 len = count;
5850 lblk1 += len;
5851 lblk2 += len;
5852 count -= len;
5853 goto repeat;
5854 }
5855
5856 /* Prepare left boundary */
5857 if (e1_blk < lblk1) {
5858 split = 1;
5859 *erp = ext4_force_split_extent_at(handle, inode1,
5860 &path1, lblk1, 0);
5861 if (unlikely(*erp))
5862 goto finish;
5863 }
5864 if (e2_blk < lblk2) {
5865 split = 1;
5866 *erp = ext4_force_split_extent_at(handle, inode2,
5867 &path2, lblk2, 0);
5868 if (unlikely(*erp))
5869 goto finish;
5870 }
5871 /* ext4_split_extent_at() may result in leaf extent split,
5872 * path must to be revalidated. */
5873 if (split)
5874 goto repeat;
5875
5876 /* Prepare right boundary */
5877 len = count;
5878 if (len > e1_blk + e1_len - lblk1)
5879 len = e1_blk + e1_len - lblk1;
5880 if (len > e2_blk + e2_len - lblk2)
5881 len = e2_blk + e2_len - lblk2;
5882
5883 if (len != e1_len) {
5884 split = 1;
5885 *erp = ext4_force_split_extent_at(handle, inode1,
5886 &path1, lblk1 + len, 0);
5887 if (unlikely(*erp))
5888 goto finish;
5889 }
5890 if (len != e2_len) {
5891 split = 1;
5892 *erp = ext4_force_split_extent_at(handle, inode2,
5893 &path2, lblk2 + len, 0);
5894 if (*erp)
5895 goto finish;
5896 }
5897 /* ext4_split_extent_at() may result in leaf extent split,
5898 * path must to be revalidated. */
5899 if (split)
5900 goto repeat;
5901
5902 BUG_ON(e2_len != e1_len);
5903 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5904 if (unlikely(*erp))
5905 goto finish;
5906 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5907 if (unlikely(*erp))
5908 goto finish;
5909
5910 /* Both extents are fully inside boundaries. Swap it now */
5911 tmp_ex = *ex1;
5912 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5913 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5914 ex1->ee_len = cpu_to_le16(e2_len);
5915 ex2->ee_len = cpu_to_le16(e1_len);
5916 if (unwritten)
5917 ext4_ext_mark_unwritten(ex2);
5918 if (ext4_ext_is_unwritten(&tmp_ex))
5919 ext4_ext_mark_unwritten(ex1);
5920
5921 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5922 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5923 *erp = ext4_ext_dirty(handle, inode2, path2 +
5924 path2->p_depth);
5925 if (unlikely(*erp))
5926 goto finish;
5927 *erp = ext4_ext_dirty(handle, inode1, path1 +
5928 path1->p_depth);
5929 /*
5930 * Looks scarry ah..? second inode already points to new blocks,
5931 * and it was successfully dirtied. But luckily error may happen
5932 * only due to journal error, so full transaction will be
5933 * aborted anyway.
5934 */
5935 if (unlikely(*erp))
5936 goto finish;
5937 lblk1 += len;
5938 lblk2 += len;
5939 replaced_count += len;
5940 count -= len;
5941
5942 repeat:
5943 ext4_ext_drop_refs(path1);
5944 kfree(path1);
5945 ext4_ext_drop_refs(path2);
5946 kfree(path2);
5947 path1 = path2 = NULL;
5948 }
5949 return replaced_count;
5950}
5951
5952/*
5953 * ext4_clu_mapped - determine whether any block in a logical cluster has
5954 * been mapped to a physical cluster
5955 *
5956 * @inode - file containing the logical cluster
5957 * @lclu - logical cluster of interest
5958 *
5959 * Returns 1 if any block in the logical cluster is mapped, signifying
5960 * that a physical cluster has been allocated for it. Otherwise,
5961 * returns 0. Can also return negative error codes. Derived from
5962 * ext4_ext_map_blocks().
5963 */
5964int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5965{
5966 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5967 struct ext4_ext_path *path;
5968 int depth, mapped = 0, err = 0;
5969 struct ext4_extent *extent;
5970 ext4_lblk_t first_lblk, first_lclu, last_lclu;
5971
5972 /* search for the extent closest to the first block in the cluster */
5973 path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5974 if (IS_ERR(path)) {
5975 err = PTR_ERR(path);
5976 path = NULL;
5977 goto out;
5978 }
5979
5980 depth = ext_depth(inode);
5981
5982 /*
5983 * A consistent leaf must not be empty. This situation is possible,
5984 * though, _during_ tree modification, and it's why an assert can't
5985 * be put in ext4_find_extent().
5986 */
5987 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5988 EXT4_ERROR_INODE(inode,
5989 "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5990 (unsigned long) EXT4_C2B(sbi, lclu),
5991 depth, path[depth].p_block);
5992 err = -EFSCORRUPTED;
5993 goto out;
5994 }
5995
5996 extent = path[depth].p_ext;
5997
5998 /* can't be mapped if the extent tree is empty */
5999 if (extent == NULL)
6000 goto out;
6001
6002 first_lblk = le32_to_cpu(extent->ee_block);
6003 first_lclu = EXT4_B2C(sbi, first_lblk);
6004
6005 /*
6006 * Three possible outcomes at this point - found extent spanning
6007 * the target cluster, to the left of the target cluster, or to the
6008 * right of the target cluster. The first two cases are handled here.
6009 * The last case indicates the target cluster is not mapped.
6010 */
6011 if (lclu >= first_lclu) {
6012 last_lclu = EXT4_B2C(sbi, first_lblk +
6013 ext4_ext_get_actual_len(extent) - 1);
6014 if (lclu <= last_lclu) {
6015 mapped = 1;
6016 } else {
6017 first_lblk = ext4_ext_next_allocated_block(path);
6018 first_lclu = EXT4_B2C(sbi, first_lblk);
6019 if (lclu == first_lclu)
6020 mapped = 1;
6021 }
6022 }
6023
6024out:
6025 ext4_ext_drop_refs(path);
6026 kfree(path);
6027
6028 return err ? err : mapped;
6029}