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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/fs.h>
33#include <linux/time.h>
34#include <linux/jbd2.h>
35#include <linux/highuid.h>
36#include <linux/pagemap.h>
37#include <linux/quotaops.h>
38#include <linux/string.h>
39#include <linux/slab.h>
40#include <linux/falloc.h>
41#include <asm/uaccess.h>
42#include <linux/fiemap.h>
43#include "ext4_jbd2.h"
44
45#include <trace/events/ext4.h>
46
47/*
48 * used by extent splitting.
49 */
50#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
51 due to ENOSPC */
52#define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */
53#define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */
54
55static __le32 ext4_extent_block_csum(struct inode *inode,
56 struct ext4_extent_header *eh)
57{
58 struct ext4_inode_info *ei = EXT4_I(inode);
59 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
60 __u32 csum;
61
62 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
63 EXT4_EXTENT_TAIL_OFFSET(eh));
64 return cpu_to_le32(csum);
65}
66
67static int ext4_extent_block_csum_verify(struct inode *inode,
68 struct ext4_extent_header *eh)
69{
70 struct ext4_extent_tail *et;
71
72 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
73 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
74 return 1;
75
76 et = find_ext4_extent_tail(eh);
77 if (et->et_checksum != ext4_extent_block_csum(inode, eh))
78 return 0;
79 return 1;
80}
81
82static void ext4_extent_block_csum_set(struct inode *inode,
83 struct ext4_extent_header *eh)
84{
85 struct ext4_extent_tail *et;
86
87 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
88 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
89 return;
90
91 et = find_ext4_extent_tail(eh);
92 et->et_checksum = ext4_extent_block_csum(inode, eh);
93}
94
95static int ext4_split_extent(handle_t *handle,
96 struct inode *inode,
97 struct ext4_ext_path *path,
98 struct ext4_map_blocks *map,
99 int split_flag,
100 int flags);
101
102static int ext4_split_extent_at(handle_t *handle,
103 struct inode *inode,
104 struct ext4_ext_path *path,
105 ext4_lblk_t split,
106 int split_flag,
107 int flags);
108
109static int ext4_ext_truncate_extend_restart(handle_t *handle,
110 struct inode *inode,
111 int needed)
112{
113 int err;
114
115 if (!ext4_handle_valid(handle))
116 return 0;
117 if (handle->h_buffer_credits > needed)
118 return 0;
119 err = ext4_journal_extend(handle, needed);
120 if (err <= 0)
121 return err;
122 err = ext4_truncate_restart_trans(handle, inode, needed);
123 if (err == 0)
124 err = -EAGAIN;
125
126 return err;
127}
128
129/*
130 * could return:
131 * - EROFS
132 * - ENOMEM
133 */
134static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
135 struct ext4_ext_path *path)
136{
137 if (path->p_bh) {
138 /* path points to block */
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 */
152#define ext4_ext_dirty(handle, inode, path) \
153 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
154static int __ext4_ext_dirty(const char *where, unsigned int line,
155 handle_t *handle, struct inode *inode,
156 struct ext4_ext_path *path)
157{
158 int err;
159 if (path->p_bh) {
160 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
161 /* path points to block */
162 err = __ext4_handle_dirty_metadata(where, line, handle,
163 inode, path->p_bh);
164 } else {
165 /* path points to leaf/index in inode body */
166 err = ext4_mark_inode_dirty(handle, inode);
167 }
168 return err;
169}
170
171static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
172 struct ext4_ext_path *path,
173 ext4_lblk_t block)
174{
175 if (path) {
176 int depth = path->p_depth;
177 struct ext4_extent *ex;
178
179 /*
180 * Try to predict block placement assuming that we are
181 * filling in a file which will eventually be
182 * non-sparse --- i.e., in the case of libbfd writing
183 * an ELF object sections out-of-order but in a way
184 * the eventually results in a contiguous object or
185 * executable file, or some database extending a table
186 * space file. However, this is actually somewhat
187 * non-ideal if we are writing a sparse file such as
188 * qemu or KVM writing a raw image file that is going
189 * to stay fairly sparse, since it will end up
190 * fragmenting the file system's free space. Maybe we
191 * should have some hueristics or some way to allow
192 * userspace to pass a hint to file system,
193 * especially if the latter case turns out to be
194 * common.
195 */
196 ex = path[depth].p_ext;
197 if (ex) {
198 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
199 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
200
201 if (block > ext_block)
202 return ext_pblk + (block - ext_block);
203 else
204 return ext_pblk - (ext_block - block);
205 }
206
207 /* it looks like index is empty;
208 * try to find starting block from index itself */
209 if (path[depth].p_bh)
210 return path[depth].p_bh->b_blocknr;
211 }
212
213 /* OK. use inode's group */
214 return ext4_inode_to_goal_block(inode);
215}
216
217/*
218 * Allocation for a meta data block
219 */
220static ext4_fsblk_t
221ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
222 struct ext4_ext_path *path,
223 struct ext4_extent *ex, int *err, unsigned int flags)
224{
225 ext4_fsblk_t goal, newblock;
226
227 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
228 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
229 NULL, err);
230 return newblock;
231}
232
233static inline int ext4_ext_space_block(struct inode *inode, int check)
234{
235 int size;
236
237 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
238 / sizeof(struct ext4_extent);
239#ifdef AGGRESSIVE_TEST
240 if (!check && size > 6)
241 size = 6;
242#endif
243 return size;
244}
245
246static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
247{
248 int size;
249
250 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
251 / sizeof(struct ext4_extent_idx);
252#ifdef AGGRESSIVE_TEST
253 if (!check && size > 5)
254 size = 5;
255#endif
256 return size;
257}
258
259static inline int ext4_ext_space_root(struct inode *inode, int check)
260{
261 int size;
262
263 size = sizeof(EXT4_I(inode)->i_data);
264 size -= sizeof(struct ext4_extent_header);
265 size /= sizeof(struct ext4_extent);
266#ifdef AGGRESSIVE_TEST
267 if (!check && size > 3)
268 size = 3;
269#endif
270 return size;
271}
272
273static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
274{
275 int size;
276
277 size = sizeof(EXT4_I(inode)->i_data);
278 size -= sizeof(struct ext4_extent_header);
279 size /= sizeof(struct ext4_extent_idx);
280#ifdef AGGRESSIVE_TEST
281 if (!check && size > 4)
282 size = 4;
283#endif
284 return size;
285}
286
287/*
288 * Calculate the number of metadata blocks needed
289 * to allocate @blocks
290 * Worse case is one block per extent
291 */
292int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
293{
294 struct ext4_inode_info *ei = EXT4_I(inode);
295 int idxs;
296
297 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
298 / sizeof(struct ext4_extent_idx));
299
300 /*
301 * If the new delayed allocation block is contiguous with the
302 * previous da block, it can share index blocks with the
303 * previous block, so we only need to allocate a new index
304 * block every idxs leaf blocks. At ldxs**2 blocks, we need
305 * an additional index block, and at ldxs**3 blocks, yet
306 * another index blocks.
307 */
308 if (ei->i_da_metadata_calc_len &&
309 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
310 int num = 0;
311
312 if ((ei->i_da_metadata_calc_len % idxs) == 0)
313 num++;
314 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
315 num++;
316 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
317 num++;
318 ei->i_da_metadata_calc_len = 0;
319 } else
320 ei->i_da_metadata_calc_len++;
321 ei->i_da_metadata_calc_last_lblock++;
322 return num;
323 }
324
325 /*
326 * In the worst case we need a new set of index blocks at
327 * every level of the inode's extent tree.
328 */
329 ei->i_da_metadata_calc_len = 1;
330 ei->i_da_metadata_calc_last_lblock = lblock;
331 return ext_depth(inode) + 1;
332}
333
334static int
335ext4_ext_max_entries(struct inode *inode, int depth)
336{
337 int max;
338
339 if (depth == ext_depth(inode)) {
340 if (depth == 0)
341 max = ext4_ext_space_root(inode, 1);
342 else
343 max = ext4_ext_space_root_idx(inode, 1);
344 } else {
345 if (depth == 0)
346 max = ext4_ext_space_block(inode, 1);
347 else
348 max = ext4_ext_space_block_idx(inode, 1);
349 }
350
351 return max;
352}
353
354static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
355{
356 ext4_fsblk_t block = ext4_ext_pblock(ext);
357 int len = ext4_ext_get_actual_len(ext);
358
359 if (len == 0)
360 return 0;
361 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
362}
363
364static int ext4_valid_extent_idx(struct inode *inode,
365 struct ext4_extent_idx *ext_idx)
366{
367 ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
368
369 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
370}
371
372static int ext4_valid_extent_entries(struct inode *inode,
373 struct ext4_extent_header *eh,
374 int depth)
375{
376 unsigned short entries;
377 if (eh->eh_entries == 0)
378 return 1;
379
380 entries = le16_to_cpu(eh->eh_entries);
381
382 if (depth == 0) {
383 /* leaf entries */
384 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
385 while (entries) {
386 if (!ext4_valid_extent(inode, ext))
387 return 0;
388 ext++;
389 entries--;
390 }
391 } else {
392 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
393 while (entries) {
394 if (!ext4_valid_extent_idx(inode, ext_idx))
395 return 0;
396 ext_idx++;
397 entries--;
398 }
399 }
400 return 1;
401}
402
403static int __ext4_ext_check(const char *function, unsigned int line,
404 struct inode *inode, struct ext4_extent_header *eh,
405 int depth)
406{
407 const char *error_msg;
408 int max = 0;
409
410 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
411 error_msg = "invalid magic";
412 goto corrupted;
413 }
414 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
415 error_msg = "unexpected eh_depth";
416 goto corrupted;
417 }
418 if (unlikely(eh->eh_max == 0)) {
419 error_msg = "invalid eh_max";
420 goto corrupted;
421 }
422 max = ext4_ext_max_entries(inode, depth);
423 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
424 error_msg = "too large eh_max";
425 goto corrupted;
426 }
427 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
428 error_msg = "invalid eh_entries";
429 goto corrupted;
430 }
431 if (!ext4_valid_extent_entries(inode, eh, depth)) {
432 error_msg = "invalid extent entries";
433 goto corrupted;
434 }
435 /* Verify checksum on non-root extent tree nodes */
436 if (ext_depth(inode) != depth &&
437 !ext4_extent_block_csum_verify(inode, eh)) {
438 error_msg = "extent tree corrupted";
439 goto corrupted;
440 }
441 return 0;
442
443corrupted:
444 ext4_error_inode(inode, function, line, 0,
445 "bad header/extent: %s - magic %x, "
446 "entries %u, max %u(%u), depth %u(%u)",
447 error_msg, le16_to_cpu(eh->eh_magic),
448 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
449 max, le16_to_cpu(eh->eh_depth), depth);
450
451 return -EIO;
452}
453
454#define ext4_ext_check(inode, eh, depth) \
455 __ext4_ext_check(__func__, __LINE__, inode, eh, depth)
456
457int ext4_ext_check_inode(struct inode *inode)
458{
459 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
460}
461
462static int __ext4_ext_check_block(const char *function, unsigned int line,
463 struct inode *inode,
464 struct ext4_extent_header *eh,
465 int depth,
466 struct buffer_head *bh)
467{
468 int ret;
469
470 if (buffer_verified(bh))
471 return 0;
472 ret = ext4_ext_check(inode, eh, depth);
473 if (ret)
474 return ret;
475 set_buffer_verified(bh);
476 return ret;
477}
478
479#define ext4_ext_check_block(inode, eh, depth, bh) \
480 __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh)
481
482#ifdef EXT_DEBUG
483static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
484{
485 int k, l = path->p_depth;
486
487 ext_debug("path:");
488 for (k = 0; k <= l; k++, path++) {
489 if (path->p_idx) {
490 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
491 ext4_idx_pblock(path->p_idx));
492 } else if (path->p_ext) {
493 ext_debug(" %d:[%d]%d:%llu ",
494 le32_to_cpu(path->p_ext->ee_block),
495 ext4_ext_is_uninitialized(path->p_ext),
496 ext4_ext_get_actual_len(path->p_ext),
497 ext4_ext_pblock(path->p_ext));
498 } else
499 ext_debug(" []");
500 }
501 ext_debug("\n");
502}
503
504static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
505{
506 int depth = ext_depth(inode);
507 struct ext4_extent_header *eh;
508 struct ext4_extent *ex;
509 int i;
510
511 if (!path)
512 return;
513
514 eh = path[depth].p_hdr;
515 ex = EXT_FIRST_EXTENT(eh);
516
517 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
518
519 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
520 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
521 ext4_ext_is_uninitialized(ex),
522 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
523 }
524 ext_debug("\n");
525}
526
527static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
528 ext4_fsblk_t newblock, int level)
529{
530 int depth = ext_depth(inode);
531 struct ext4_extent *ex;
532
533 if (depth != level) {
534 struct ext4_extent_idx *idx;
535 idx = path[level].p_idx;
536 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
537 ext_debug("%d: move %d:%llu in new index %llu\n", level,
538 le32_to_cpu(idx->ei_block),
539 ext4_idx_pblock(idx),
540 newblock);
541 idx++;
542 }
543
544 return;
545 }
546
547 ex = path[depth].p_ext;
548 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
549 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
550 le32_to_cpu(ex->ee_block),
551 ext4_ext_pblock(ex),
552 ext4_ext_is_uninitialized(ex),
553 ext4_ext_get_actual_len(ex),
554 newblock);
555 ex++;
556 }
557}
558
559#else
560#define ext4_ext_show_path(inode, path)
561#define ext4_ext_show_leaf(inode, path)
562#define ext4_ext_show_move(inode, path, newblock, level)
563#endif
564
565void ext4_ext_drop_refs(struct ext4_ext_path *path)
566{
567 int depth = path->p_depth;
568 int i;
569
570 for (i = 0; i <= depth; i++, path++)
571 if (path->p_bh) {
572 brelse(path->p_bh);
573 path->p_bh = NULL;
574 }
575}
576
577/*
578 * ext4_ext_binsearch_idx:
579 * binary search for the closest index of the given block
580 * the header must be checked before calling this
581 */
582static void
583ext4_ext_binsearch_idx(struct inode *inode,
584 struct ext4_ext_path *path, ext4_lblk_t block)
585{
586 struct ext4_extent_header *eh = path->p_hdr;
587 struct ext4_extent_idx *r, *l, *m;
588
589
590 ext_debug("binsearch for %u(idx): ", block);
591
592 l = EXT_FIRST_INDEX(eh) + 1;
593 r = EXT_LAST_INDEX(eh);
594 while (l <= r) {
595 m = l + (r - l) / 2;
596 if (block < le32_to_cpu(m->ei_block))
597 r = m - 1;
598 else
599 l = m + 1;
600 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
601 m, le32_to_cpu(m->ei_block),
602 r, le32_to_cpu(r->ei_block));
603 }
604
605 path->p_idx = l - 1;
606 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
607 ext4_idx_pblock(path->p_idx));
608
609#ifdef CHECK_BINSEARCH
610 {
611 struct ext4_extent_idx *chix, *ix;
612 int k;
613
614 chix = ix = EXT_FIRST_INDEX(eh);
615 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
616 if (k != 0 &&
617 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
618 printk(KERN_DEBUG "k=%d, ix=0x%p, "
619 "first=0x%p\n", k,
620 ix, EXT_FIRST_INDEX(eh));
621 printk(KERN_DEBUG "%u <= %u\n",
622 le32_to_cpu(ix->ei_block),
623 le32_to_cpu(ix[-1].ei_block));
624 }
625 BUG_ON(k && le32_to_cpu(ix->ei_block)
626 <= le32_to_cpu(ix[-1].ei_block));
627 if (block < le32_to_cpu(ix->ei_block))
628 break;
629 chix = ix;
630 }
631 BUG_ON(chix != path->p_idx);
632 }
633#endif
634
635}
636
637/*
638 * ext4_ext_binsearch:
639 * binary search for closest extent of the given block
640 * the header must be checked before calling this
641 */
642static void
643ext4_ext_binsearch(struct inode *inode,
644 struct ext4_ext_path *path, ext4_lblk_t block)
645{
646 struct ext4_extent_header *eh = path->p_hdr;
647 struct ext4_extent *r, *l, *m;
648
649 if (eh->eh_entries == 0) {
650 /*
651 * this leaf is empty:
652 * we get such a leaf in split/add case
653 */
654 return;
655 }
656
657 ext_debug("binsearch for %u: ", block);
658
659 l = EXT_FIRST_EXTENT(eh) + 1;
660 r = EXT_LAST_EXTENT(eh);
661
662 while (l <= r) {
663 m = l + (r - l) / 2;
664 if (block < le32_to_cpu(m->ee_block))
665 r = m - 1;
666 else
667 l = m + 1;
668 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
669 m, le32_to_cpu(m->ee_block),
670 r, le32_to_cpu(r->ee_block));
671 }
672
673 path->p_ext = l - 1;
674 ext_debug(" -> %d:%llu:[%d]%d ",
675 le32_to_cpu(path->p_ext->ee_block),
676 ext4_ext_pblock(path->p_ext),
677 ext4_ext_is_uninitialized(path->p_ext),
678 ext4_ext_get_actual_len(path->p_ext));
679
680#ifdef CHECK_BINSEARCH
681 {
682 struct ext4_extent *chex, *ex;
683 int k;
684
685 chex = ex = EXT_FIRST_EXTENT(eh);
686 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
687 BUG_ON(k && le32_to_cpu(ex->ee_block)
688 <= le32_to_cpu(ex[-1].ee_block));
689 if (block < le32_to_cpu(ex->ee_block))
690 break;
691 chex = ex;
692 }
693 BUG_ON(chex != path->p_ext);
694 }
695#endif
696
697}
698
699int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
700{
701 struct ext4_extent_header *eh;
702
703 eh = ext_inode_hdr(inode);
704 eh->eh_depth = 0;
705 eh->eh_entries = 0;
706 eh->eh_magic = EXT4_EXT_MAGIC;
707 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
708 ext4_mark_inode_dirty(handle, inode);
709 ext4_ext_invalidate_cache(inode);
710 return 0;
711}
712
713struct ext4_ext_path *
714ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
715 struct ext4_ext_path *path)
716{
717 struct ext4_extent_header *eh;
718 struct buffer_head *bh;
719 short int depth, i, ppos = 0, alloc = 0;
720
721 eh = ext_inode_hdr(inode);
722 depth = ext_depth(inode);
723
724 /* account possible depth increase */
725 if (!path) {
726 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
727 GFP_NOFS);
728 if (!path)
729 return ERR_PTR(-ENOMEM);
730 alloc = 1;
731 }
732 path[0].p_hdr = eh;
733 path[0].p_bh = NULL;
734
735 i = depth;
736 /* walk through the tree */
737 while (i) {
738 ext_debug("depth %d: num %d, max %d\n",
739 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
740
741 ext4_ext_binsearch_idx(inode, path + ppos, block);
742 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
743 path[ppos].p_depth = i;
744 path[ppos].p_ext = NULL;
745
746 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
747 if (unlikely(!bh))
748 goto err;
749 if (!bh_uptodate_or_lock(bh)) {
750 trace_ext4_ext_load_extent(inode, block,
751 path[ppos].p_block);
752 if (bh_submit_read(bh) < 0) {
753 put_bh(bh);
754 goto err;
755 }
756 }
757 eh = ext_block_hdr(bh);
758 ppos++;
759 if (unlikely(ppos > depth)) {
760 put_bh(bh);
761 EXT4_ERROR_INODE(inode,
762 "ppos %d > depth %d", ppos, depth);
763 goto err;
764 }
765 path[ppos].p_bh = bh;
766 path[ppos].p_hdr = eh;
767 i--;
768
769 if (ext4_ext_check_block(inode, eh, i, bh))
770 goto err;
771 }
772
773 path[ppos].p_depth = i;
774 path[ppos].p_ext = NULL;
775 path[ppos].p_idx = NULL;
776
777 /* find extent */
778 ext4_ext_binsearch(inode, path + ppos, block);
779 /* if not an empty leaf */
780 if (path[ppos].p_ext)
781 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
782
783 ext4_ext_show_path(inode, path);
784
785 return path;
786
787err:
788 ext4_ext_drop_refs(path);
789 if (alloc)
790 kfree(path);
791 return ERR_PTR(-EIO);
792}
793
794/*
795 * ext4_ext_insert_index:
796 * insert new index [@logical;@ptr] into the block at @curp;
797 * check where to insert: before @curp or after @curp
798 */
799static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
800 struct ext4_ext_path *curp,
801 int logical, ext4_fsblk_t ptr)
802{
803 struct ext4_extent_idx *ix;
804 int len, err;
805
806 err = ext4_ext_get_access(handle, inode, curp);
807 if (err)
808 return err;
809
810 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
811 EXT4_ERROR_INODE(inode,
812 "logical %d == ei_block %d!",
813 logical, le32_to_cpu(curp->p_idx->ei_block));
814 return -EIO;
815 }
816
817 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
818 >= le16_to_cpu(curp->p_hdr->eh_max))) {
819 EXT4_ERROR_INODE(inode,
820 "eh_entries %d >= eh_max %d!",
821 le16_to_cpu(curp->p_hdr->eh_entries),
822 le16_to_cpu(curp->p_hdr->eh_max));
823 return -EIO;
824 }
825
826 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
827 /* insert after */
828 ext_debug("insert new index %d after: %llu\n", logical, ptr);
829 ix = curp->p_idx + 1;
830 } else {
831 /* insert before */
832 ext_debug("insert new index %d before: %llu\n", logical, ptr);
833 ix = curp->p_idx;
834 }
835
836 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
837 BUG_ON(len < 0);
838 if (len > 0) {
839 ext_debug("insert new index %d: "
840 "move %d indices from 0x%p to 0x%p\n",
841 logical, len, ix, ix + 1);
842 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
843 }
844
845 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
846 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
847 return -EIO;
848 }
849
850 ix->ei_block = cpu_to_le32(logical);
851 ext4_idx_store_pblock(ix, ptr);
852 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
853
854 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
855 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
856 return -EIO;
857 }
858
859 err = ext4_ext_dirty(handle, inode, curp);
860 ext4_std_error(inode->i_sb, err);
861
862 return err;
863}
864
865/*
866 * ext4_ext_split:
867 * inserts new subtree into the path, using free index entry
868 * at depth @at:
869 * - allocates all needed blocks (new leaf and all intermediate index blocks)
870 * - makes decision where to split
871 * - moves remaining extents and index entries (right to the split point)
872 * into the newly allocated blocks
873 * - initializes subtree
874 */
875static int ext4_ext_split(handle_t *handle, struct inode *inode,
876 unsigned int flags,
877 struct ext4_ext_path *path,
878 struct ext4_extent *newext, int at)
879{
880 struct buffer_head *bh = NULL;
881 int depth = ext_depth(inode);
882 struct ext4_extent_header *neh;
883 struct ext4_extent_idx *fidx;
884 int i = at, k, m, a;
885 ext4_fsblk_t newblock, oldblock;
886 __le32 border;
887 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
888 int err = 0;
889
890 /* make decision: where to split? */
891 /* FIXME: now decision is simplest: at current extent */
892
893 /* if current leaf will be split, then we should use
894 * border from split point */
895 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
896 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
897 return -EIO;
898 }
899 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
900 border = path[depth].p_ext[1].ee_block;
901 ext_debug("leaf will be split."
902 " next leaf starts at %d\n",
903 le32_to_cpu(border));
904 } else {
905 border = newext->ee_block;
906 ext_debug("leaf will be added."
907 " next leaf starts at %d\n",
908 le32_to_cpu(border));
909 }
910
911 /*
912 * If error occurs, then we break processing
913 * and mark filesystem read-only. index won't
914 * be inserted and tree will be in consistent
915 * state. Next mount will repair buffers too.
916 */
917
918 /*
919 * Get array to track all allocated blocks.
920 * We need this to handle errors and free blocks
921 * upon them.
922 */
923 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
924 if (!ablocks)
925 return -ENOMEM;
926
927 /* allocate all needed blocks */
928 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
929 for (a = 0; a < depth - at; a++) {
930 newblock = ext4_ext_new_meta_block(handle, inode, path,
931 newext, &err, flags);
932 if (newblock == 0)
933 goto cleanup;
934 ablocks[a] = newblock;
935 }
936
937 /* initialize new leaf */
938 newblock = ablocks[--a];
939 if (unlikely(newblock == 0)) {
940 EXT4_ERROR_INODE(inode, "newblock == 0!");
941 err = -EIO;
942 goto cleanup;
943 }
944 bh = sb_getblk(inode->i_sb, newblock);
945 if (!bh) {
946 err = -EIO;
947 goto cleanup;
948 }
949 lock_buffer(bh);
950
951 err = ext4_journal_get_create_access(handle, bh);
952 if (err)
953 goto cleanup;
954
955 neh = ext_block_hdr(bh);
956 neh->eh_entries = 0;
957 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
958 neh->eh_magic = EXT4_EXT_MAGIC;
959 neh->eh_depth = 0;
960
961 /* move remainder of path[depth] to the new leaf */
962 if (unlikely(path[depth].p_hdr->eh_entries !=
963 path[depth].p_hdr->eh_max)) {
964 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
965 path[depth].p_hdr->eh_entries,
966 path[depth].p_hdr->eh_max);
967 err = -EIO;
968 goto cleanup;
969 }
970 /* start copy from next extent */
971 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
972 ext4_ext_show_move(inode, path, newblock, depth);
973 if (m) {
974 struct ext4_extent *ex;
975 ex = EXT_FIRST_EXTENT(neh);
976 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
977 le16_add_cpu(&neh->eh_entries, m);
978 }
979
980 ext4_extent_block_csum_set(inode, neh);
981 set_buffer_uptodate(bh);
982 unlock_buffer(bh);
983
984 err = ext4_handle_dirty_metadata(handle, inode, bh);
985 if (err)
986 goto cleanup;
987 brelse(bh);
988 bh = NULL;
989
990 /* correct old leaf */
991 if (m) {
992 err = ext4_ext_get_access(handle, inode, path + depth);
993 if (err)
994 goto cleanup;
995 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
996 err = ext4_ext_dirty(handle, inode, path + depth);
997 if (err)
998 goto cleanup;
999
1000 }
1001
1002 /* create intermediate indexes */
1003 k = depth - at - 1;
1004 if (unlikely(k < 0)) {
1005 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1006 err = -EIO;
1007 goto cleanup;
1008 }
1009 if (k)
1010 ext_debug("create %d intermediate indices\n", k);
1011 /* insert new index into current index block */
1012 /* current depth stored in i var */
1013 i = depth - 1;
1014 while (k--) {
1015 oldblock = newblock;
1016 newblock = ablocks[--a];
1017 bh = sb_getblk(inode->i_sb, newblock);
1018 if (!bh) {
1019 err = -EIO;
1020 goto cleanup;
1021 }
1022 lock_buffer(bh);
1023
1024 err = ext4_journal_get_create_access(handle, bh);
1025 if (err)
1026 goto cleanup;
1027
1028 neh = ext_block_hdr(bh);
1029 neh->eh_entries = cpu_to_le16(1);
1030 neh->eh_magic = EXT4_EXT_MAGIC;
1031 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1032 neh->eh_depth = cpu_to_le16(depth - i);
1033 fidx = EXT_FIRST_INDEX(neh);
1034 fidx->ei_block = border;
1035 ext4_idx_store_pblock(fidx, oldblock);
1036
1037 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1038 i, newblock, le32_to_cpu(border), oldblock);
1039
1040 /* move remainder of path[i] to the new index block */
1041 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1042 EXT_LAST_INDEX(path[i].p_hdr))) {
1043 EXT4_ERROR_INODE(inode,
1044 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1045 le32_to_cpu(path[i].p_ext->ee_block));
1046 err = -EIO;
1047 goto cleanup;
1048 }
1049 /* start copy indexes */
1050 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1051 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1052 EXT_MAX_INDEX(path[i].p_hdr));
1053 ext4_ext_show_move(inode, path, newblock, i);
1054 if (m) {
1055 memmove(++fidx, path[i].p_idx,
1056 sizeof(struct ext4_extent_idx) * m);
1057 le16_add_cpu(&neh->eh_entries, m);
1058 }
1059 ext4_extent_block_csum_set(inode, neh);
1060 set_buffer_uptodate(bh);
1061 unlock_buffer(bh);
1062
1063 err = ext4_handle_dirty_metadata(handle, inode, bh);
1064 if (err)
1065 goto cleanup;
1066 brelse(bh);
1067 bh = NULL;
1068
1069 /* correct old index */
1070 if (m) {
1071 err = ext4_ext_get_access(handle, inode, path + i);
1072 if (err)
1073 goto cleanup;
1074 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1075 err = ext4_ext_dirty(handle, inode, path + i);
1076 if (err)
1077 goto cleanup;
1078 }
1079
1080 i--;
1081 }
1082
1083 /* insert new index */
1084 err = ext4_ext_insert_index(handle, inode, path + at,
1085 le32_to_cpu(border), newblock);
1086
1087cleanup:
1088 if (bh) {
1089 if (buffer_locked(bh))
1090 unlock_buffer(bh);
1091 brelse(bh);
1092 }
1093
1094 if (err) {
1095 /* free all allocated blocks in error case */
1096 for (i = 0; i < depth; i++) {
1097 if (!ablocks[i])
1098 continue;
1099 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1100 EXT4_FREE_BLOCKS_METADATA);
1101 }
1102 }
1103 kfree(ablocks);
1104
1105 return err;
1106}
1107
1108/*
1109 * ext4_ext_grow_indepth:
1110 * implements tree growing procedure:
1111 * - allocates new block
1112 * - moves top-level data (index block or leaf) into the new block
1113 * - initializes new top-level, creating index that points to the
1114 * just created block
1115 */
1116static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1117 unsigned int flags,
1118 struct ext4_extent *newext)
1119{
1120 struct ext4_extent_header *neh;
1121 struct buffer_head *bh;
1122 ext4_fsblk_t newblock;
1123 int err = 0;
1124
1125 newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1126 newext, &err, flags);
1127 if (newblock == 0)
1128 return err;
1129
1130 bh = sb_getblk(inode->i_sb, newblock);
1131 if (!bh) {
1132 err = -EIO;
1133 ext4_std_error(inode->i_sb, err);
1134 return err;
1135 }
1136 lock_buffer(bh);
1137
1138 err = ext4_journal_get_create_access(handle, bh);
1139 if (err) {
1140 unlock_buffer(bh);
1141 goto out;
1142 }
1143
1144 /* move top-level index/leaf into new block */
1145 memmove(bh->b_data, EXT4_I(inode)->i_data,
1146 sizeof(EXT4_I(inode)->i_data));
1147
1148 /* set size of new block */
1149 neh = ext_block_hdr(bh);
1150 /* old root could have indexes or leaves
1151 * so calculate e_max right way */
1152 if (ext_depth(inode))
1153 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1154 else
1155 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1156 neh->eh_magic = EXT4_EXT_MAGIC;
1157 ext4_extent_block_csum_set(inode, neh);
1158 set_buffer_uptodate(bh);
1159 unlock_buffer(bh);
1160
1161 err = ext4_handle_dirty_metadata(handle, inode, bh);
1162 if (err)
1163 goto out;
1164
1165 /* Update top-level index: num,max,pointer */
1166 neh = ext_inode_hdr(inode);
1167 neh->eh_entries = cpu_to_le16(1);
1168 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1169 if (neh->eh_depth == 0) {
1170 /* Root extent block becomes index block */
1171 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1172 EXT_FIRST_INDEX(neh)->ei_block =
1173 EXT_FIRST_EXTENT(neh)->ee_block;
1174 }
1175 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1176 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1177 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1178 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1179
1180 neh->eh_depth = cpu_to_le16(le16_to_cpu(neh->eh_depth) + 1);
1181 ext4_mark_inode_dirty(handle, inode);
1182out:
1183 brelse(bh);
1184
1185 return err;
1186}
1187
1188/*
1189 * ext4_ext_create_new_leaf:
1190 * finds empty index and adds new leaf.
1191 * if no free index is found, then it requests in-depth growing.
1192 */
1193static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1194 unsigned int flags,
1195 struct ext4_ext_path *path,
1196 struct ext4_extent *newext)
1197{
1198 struct ext4_ext_path *curp;
1199 int depth, i, err = 0;
1200
1201repeat:
1202 i = depth = ext_depth(inode);
1203
1204 /* walk up to the tree and look for free index entry */
1205 curp = path + depth;
1206 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1207 i--;
1208 curp--;
1209 }
1210
1211 /* we use already allocated block for index block,
1212 * so subsequent data blocks should be contiguous */
1213 if (EXT_HAS_FREE_INDEX(curp)) {
1214 /* if we found index with free entry, then use that
1215 * entry: create all needed subtree and add new leaf */
1216 err = ext4_ext_split(handle, inode, flags, path, newext, i);
1217 if (err)
1218 goto out;
1219
1220 /* refill path */
1221 ext4_ext_drop_refs(path);
1222 path = ext4_ext_find_extent(inode,
1223 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1224 path);
1225 if (IS_ERR(path))
1226 err = PTR_ERR(path);
1227 } else {
1228 /* tree is full, time to grow in depth */
1229 err = ext4_ext_grow_indepth(handle, inode, flags, newext);
1230 if (err)
1231 goto out;
1232
1233 /* refill path */
1234 ext4_ext_drop_refs(path);
1235 path = ext4_ext_find_extent(inode,
1236 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1237 path);
1238 if (IS_ERR(path)) {
1239 err = PTR_ERR(path);
1240 goto out;
1241 }
1242
1243 /*
1244 * only first (depth 0 -> 1) produces free space;
1245 * in all other cases we have to split the grown tree
1246 */
1247 depth = ext_depth(inode);
1248 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1249 /* now we need to split */
1250 goto repeat;
1251 }
1252 }
1253
1254out:
1255 return err;
1256}
1257
1258/*
1259 * search the closest allocated block to the left for *logical
1260 * and returns it at @logical + it's physical address at @phys
1261 * if *logical is the smallest allocated block, the function
1262 * returns 0 at @phys
1263 * return value contains 0 (success) or error code
1264 */
1265static int ext4_ext_search_left(struct inode *inode,
1266 struct ext4_ext_path *path,
1267 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1268{
1269 struct ext4_extent_idx *ix;
1270 struct ext4_extent *ex;
1271 int depth, ee_len;
1272
1273 if (unlikely(path == NULL)) {
1274 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1275 return -EIO;
1276 }
1277 depth = path->p_depth;
1278 *phys = 0;
1279
1280 if (depth == 0 && path->p_ext == NULL)
1281 return 0;
1282
1283 /* usually extent in the path covers blocks smaller
1284 * then *logical, but it can be that extent is the
1285 * first one in the file */
1286
1287 ex = path[depth].p_ext;
1288 ee_len = ext4_ext_get_actual_len(ex);
1289 if (*logical < le32_to_cpu(ex->ee_block)) {
1290 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1291 EXT4_ERROR_INODE(inode,
1292 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1293 *logical, le32_to_cpu(ex->ee_block));
1294 return -EIO;
1295 }
1296 while (--depth >= 0) {
1297 ix = path[depth].p_idx;
1298 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1299 EXT4_ERROR_INODE(inode,
1300 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1301 ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1302 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1303 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1304 depth);
1305 return -EIO;
1306 }
1307 }
1308 return 0;
1309 }
1310
1311 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1312 EXT4_ERROR_INODE(inode,
1313 "logical %d < ee_block %d + ee_len %d!",
1314 *logical, le32_to_cpu(ex->ee_block), ee_len);
1315 return -EIO;
1316 }
1317
1318 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1319 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1320 return 0;
1321}
1322
1323/*
1324 * search the closest allocated block to the right for *logical
1325 * and returns it at @logical + it's physical address at @phys
1326 * if *logical is the largest allocated block, the function
1327 * returns 0 at @phys
1328 * return value contains 0 (success) or error code
1329 */
1330static int ext4_ext_search_right(struct inode *inode,
1331 struct ext4_ext_path *path,
1332 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1333 struct ext4_extent **ret_ex)
1334{
1335 struct buffer_head *bh = NULL;
1336 struct ext4_extent_header *eh;
1337 struct ext4_extent_idx *ix;
1338 struct ext4_extent *ex;
1339 ext4_fsblk_t block;
1340 int depth; /* Note, NOT eh_depth; depth from top of tree */
1341 int ee_len;
1342
1343 if (unlikely(path == NULL)) {
1344 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1345 return -EIO;
1346 }
1347 depth = path->p_depth;
1348 *phys = 0;
1349
1350 if (depth == 0 && path->p_ext == NULL)
1351 return 0;
1352
1353 /* usually extent in the path covers blocks smaller
1354 * then *logical, but it can be that extent is the
1355 * first one in the file */
1356
1357 ex = path[depth].p_ext;
1358 ee_len = ext4_ext_get_actual_len(ex);
1359 if (*logical < le32_to_cpu(ex->ee_block)) {
1360 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1361 EXT4_ERROR_INODE(inode,
1362 "first_extent(path[%d].p_hdr) != ex",
1363 depth);
1364 return -EIO;
1365 }
1366 while (--depth >= 0) {
1367 ix = path[depth].p_idx;
1368 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1369 EXT4_ERROR_INODE(inode,
1370 "ix != EXT_FIRST_INDEX *logical %d!",
1371 *logical);
1372 return -EIO;
1373 }
1374 }
1375 goto found_extent;
1376 }
1377
1378 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1379 EXT4_ERROR_INODE(inode,
1380 "logical %d < ee_block %d + ee_len %d!",
1381 *logical, le32_to_cpu(ex->ee_block), ee_len);
1382 return -EIO;
1383 }
1384
1385 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1386 /* next allocated block in this leaf */
1387 ex++;
1388 goto found_extent;
1389 }
1390
1391 /* go up and search for index to the right */
1392 while (--depth >= 0) {
1393 ix = path[depth].p_idx;
1394 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1395 goto got_index;
1396 }
1397
1398 /* we've gone up to the root and found no index to the right */
1399 return 0;
1400
1401got_index:
1402 /* we've found index to the right, let's
1403 * follow it and find the closest allocated
1404 * block to the right */
1405 ix++;
1406 block = ext4_idx_pblock(ix);
1407 while (++depth < path->p_depth) {
1408 bh = sb_bread(inode->i_sb, block);
1409 if (bh == NULL)
1410 return -EIO;
1411 eh = ext_block_hdr(bh);
1412 /* subtract from p_depth to get proper eh_depth */
1413 if (ext4_ext_check_block(inode, eh,
1414 path->p_depth - depth, bh)) {
1415 put_bh(bh);
1416 return -EIO;
1417 }
1418 ix = EXT_FIRST_INDEX(eh);
1419 block = ext4_idx_pblock(ix);
1420 put_bh(bh);
1421 }
1422
1423 bh = sb_bread(inode->i_sb, block);
1424 if (bh == NULL)
1425 return -EIO;
1426 eh = ext_block_hdr(bh);
1427 if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) {
1428 put_bh(bh);
1429 return -EIO;
1430 }
1431 ex = EXT_FIRST_EXTENT(eh);
1432found_extent:
1433 *logical = le32_to_cpu(ex->ee_block);
1434 *phys = ext4_ext_pblock(ex);
1435 *ret_ex = ex;
1436 if (bh)
1437 put_bh(bh);
1438 return 0;
1439}
1440
1441/*
1442 * ext4_ext_next_allocated_block:
1443 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1444 * NOTE: it considers block number from index entry as
1445 * allocated block. Thus, index entries have to be consistent
1446 * with leaves.
1447 */
1448static ext4_lblk_t
1449ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1450{
1451 int depth;
1452
1453 BUG_ON(path == NULL);
1454 depth = path->p_depth;
1455
1456 if (depth == 0 && path->p_ext == NULL)
1457 return EXT_MAX_BLOCKS;
1458
1459 while (depth >= 0) {
1460 if (depth == path->p_depth) {
1461 /* leaf */
1462 if (path[depth].p_ext &&
1463 path[depth].p_ext !=
1464 EXT_LAST_EXTENT(path[depth].p_hdr))
1465 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1466 } else {
1467 /* index */
1468 if (path[depth].p_idx !=
1469 EXT_LAST_INDEX(path[depth].p_hdr))
1470 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1471 }
1472 depth--;
1473 }
1474
1475 return EXT_MAX_BLOCKS;
1476}
1477
1478/*
1479 * ext4_ext_next_leaf_block:
1480 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1481 */
1482static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1483{
1484 int depth;
1485
1486 BUG_ON(path == NULL);
1487 depth = path->p_depth;
1488
1489 /* zero-tree has no leaf blocks at all */
1490 if (depth == 0)
1491 return EXT_MAX_BLOCKS;
1492
1493 /* go to index block */
1494 depth--;
1495
1496 while (depth >= 0) {
1497 if (path[depth].p_idx !=
1498 EXT_LAST_INDEX(path[depth].p_hdr))
1499 return (ext4_lblk_t)
1500 le32_to_cpu(path[depth].p_idx[1].ei_block);
1501 depth--;
1502 }
1503
1504 return EXT_MAX_BLOCKS;
1505}
1506
1507/*
1508 * ext4_ext_correct_indexes:
1509 * if leaf gets modified and modified extent is first in the leaf,
1510 * then we have to correct all indexes above.
1511 * TODO: do we need to correct tree in all cases?
1512 */
1513static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1514 struct ext4_ext_path *path)
1515{
1516 struct ext4_extent_header *eh;
1517 int depth = ext_depth(inode);
1518 struct ext4_extent *ex;
1519 __le32 border;
1520 int k, err = 0;
1521
1522 eh = path[depth].p_hdr;
1523 ex = path[depth].p_ext;
1524
1525 if (unlikely(ex == NULL || eh == NULL)) {
1526 EXT4_ERROR_INODE(inode,
1527 "ex %p == NULL or eh %p == NULL", ex, eh);
1528 return -EIO;
1529 }
1530
1531 if (depth == 0) {
1532 /* there is no tree at all */
1533 return 0;
1534 }
1535
1536 if (ex != EXT_FIRST_EXTENT(eh)) {
1537 /* we correct tree if first leaf got modified only */
1538 return 0;
1539 }
1540
1541 /*
1542 * TODO: we need correction if border is smaller than current one
1543 */
1544 k = depth - 1;
1545 border = path[depth].p_ext->ee_block;
1546 err = ext4_ext_get_access(handle, inode, path + k);
1547 if (err)
1548 return err;
1549 path[k].p_idx->ei_block = border;
1550 err = ext4_ext_dirty(handle, inode, path + k);
1551 if (err)
1552 return err;
1553
1554 while (k--) {
1555 /* change all left-side indexes */
1556 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1557 break;
1558 err = ext4_ext_get_access(handle, inode, path + k);
1559 if (err)
1560 break;
1561 path[k].p_idx->ei_block = border;
1562 err = ext4_ext_dirty(handle, inode, path + k);
1563 if (err)
1564 break;
1565 }
1566
1567 return err;
1568}
1569
1570int
1571ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1572 struct ext4_extent *ex2)
1573{
1574 unsigned short ext1_ee_len, ext2_ee_len, max_len;
1575
1576 /*
1577 * Make sure that either both extents are uninitialized, or
1578 * both are _not_.
1579 */
1580 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1581 return 0;
1582
1583 if (ext4_ext_is_uninitialized(ex1))
1584 max_len = EXT_UNINIT_MAX_LEN;
1585 else
1586 max_len = EXT_INIT_MAX_LEN;
1587
1588 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1589 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1590
1591 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1592 le32_to_cpu(ex2->ee_block))
1593 return 0;
1594
1595 /*
1596 * To allow future support for preallocated extents to be added
1597 * as an RO_COMPAT feature, refuse to merge to extents if
1598 * this can result in the top bit of ee_len being set.
1599 */
1600 if (ext1_ee_len + ext2_ee_len > max_len)
1601 return 0;
1602#ifdef AGGRESSIVE_TEST
1603 if (ext1_ee_len >= 4)
1604 return 0;
1605#endif
1606
1607 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1608 return 1;
1609 return 0;
1610}
1611
1612/*
1613 * This function tries to merge the "ex" extent to the next extent in the tree.
1614 * It always tries to merge towards right. If you want to merge towards
1615 * left, pass "ex - 1" as argument instead of "ex".
1616 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1617 * 1 if they got merged.
1618 */
1619static int ext4_ext_try_to_merge_right(struct inode *inode,
1620 struct ext4_ext_path *path,
1621 struct ext4_extent *ex)
1622{
1623 struct ext4_extent_header *eh;
1624 unsigned int depth, len;
1625 int merge_done = 0;
1626 int uninitialized = 0;
1627
1628 depth = ext_depth(inode);
1629 BUG_ON(path[depth].p_hdr == NULL);
1630 eh = path[depth].p_hdr;
1631
1632 while (ex < EXT_LAST_EXTENT(eh)) {
1633 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1634 break;
1635 /* merge with next extent! */
1636 if (ext4_ext_is_uninitialized(ex))
1637 uninitialized = 1;
1638 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1639 + ext4_ext_get_actual_len(ex + 1));
1640 if (uninitialized)
1641 ext4_ext_mark_uninitialized(ex);
1642
1643 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1644 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1645 * sizeof(struct ext4_extent);
1646 memmove(ex + 1, ex + 2, len);
1647 }
1648 le16_add_cpu(&eh->eh_entries, -1);
1649 merge_done = 1;
1650 WARN_ON(eh->eh_entries == 0);
1651 if (!eh->eh_entries)
1652 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1653 }
1654
1655 return merge_done;
1656}
1657
1658/*
1659 * This function tries to merge the @ex extent to neighbours in the tree.
1660 * return 1 if merge left else 0.
1661 */
1662static int ext4_ext_try_to_merge(struct inode *inode,
1663 struct ext4_ext_path *path,
1664 struct ext4_extent *ex) {
1665 struct ext4_extent_header *eh;
1666 unsigned int depth;
1667 int merge_done = 0;
1668 int ret = 0;
1669
1670 depth = ext_depth(inode);
1671 BUG_ON(path[depth].p_hdr == NULL);
1672 eh = path[depth].p_hdr;
1673
1674 if (ex > EXT_FIRST_EXTENT(eh))
1675 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1676
1677 if (!merge_done)
1678 ret = ext4_ext_try_to_merge_right(inode, path, ex);
1679
1680 return ret;
1681}
1682
1683/*
1684 * check if a portion of the "newext" extent overlaps with an
1685 * existing extent.
1686 *
1687 * If there is an overlap discovered, it updates the length of the newext
1688 * such that there will be no overlap, and then returns 1.
1689 * If there is no overlap found, it returns 0.
1690 */
1691static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1692 struct inode *inode,
1693 struct ext4_extent *newext,
1694 struct ext4_ext_path *path)
1695{
1696 ext4_lblk_t b1, b2;
1697 unsigned int depth, len1;
1698 unsigned int ret = 0;
1699
1700 b1 = le32_to_cpu(newext->ee_block);
1701 len1 = ext4_ext_get_actual_len(newext);
1702 depth = ext_depth(inode);
1703 if (!path[depth].p_ext)
1704 goto out;
1705 b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1706 b2 &= ~(sbi->s_cluster_ratio - 1);
1707
1708 /*
1709 * get the next allocated block if the extent in the path
1710 * is before the requested block(s)
1711 */
1712 if (b2 < b1) {
1713 b2 = ext4_ext_next_allocated_block(path);
1714 if (b2 == EXT_MAX_BLOCKS)
1715 goto out;
1716 b2 &= ~(sbi->s_cluster_ratio - 1);
1717 }
1718
1719 /* check for wrap through zero on extent logical start block*/
1720 if (b1 + len1 < b1) {
1721 len1 = EXT_MAX_BLOCKS - b1;
1722 newext->ee_len = cpu_to_le16(len1);
1723 ret = 1;
1724 }
1725
1726 /* check for overlap */
1727 if (b1 + len1 > b2) {
1728 newext->ee_len = cpu_to_le16(b2 - b1);
1729 ret = 1;
1730 }
1731out:
1732 return ret;
1733}
1734
1735/*
1736 * ext4_ext_insert_extent:
1737 * tries to merge requsted extent into the existing extent or
1738 * inserts requested extent as new one into the tree,
1739 * creating new leaf in the no-space case.
1740 */
1741int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1742 struct ext4_ext_path *path,
1743 struct ext4_extent *newext, int flag)
1744{
1745 struct ext4_extent_header *eh;
1746 struct ext4_extent *ex, *fex;
1747 struct ext4_extent *nearex; /* nearest extent */
1748 struct ext4_ext_path *npath = NULL;
1749 int depth, len, err;
1750 ext4_lblk_t next;
1751 unsigned uninitialized = 0;
1752 int flags = 0;
1753
1754 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1755 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1756 return -EIO;
1757 }
1758 depth = ext_depth(inode);
1759 ex = path[depth].p_ext;
1760 if (unlikely(path[depth].p_hdr == NULL)) {
1761 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1762 return -EIO;
1763 }
1764
1765 /* try to insert block into found extent and return */
1766 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
1767 && ext4_can_extents_be_merged(inode, ex, newext)) {
1768 ext_debug("append [%d]%d block to %u:[%d]%d (from %llu)\n",
1769 ext4_ext_is_uninitialized(newext),
1770 ext4_ext_get_actual_len(newext),
1771 le32_to_cpu(ex->ee_block),
1772 ext4_ext_is_uninitialized(ex),
1773 ext4_ext_get_actual_len(ex),
1774 ext4_ext_pblock(ex));
1775 err = ext4_ext_get_access(handle, inode, path + depth);
1776 if (err)
1777 return err;
1778
1779 /*
1780 * ext4_can_extents_be_merged should have checked that either
1781 * both extents are uninitialized, or both aren't. Thus we
1782 * need to check only one of them here.
1783 */
1784 if (ext4_ext_is_uninitialized(ex))
1785 uninitialized = 1;
1786 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1787 + ext4_ext_get_actual_len(newext));
1788 if (uninitialized)
1789 ext4_ext_mark_uninitialized(ex);
1790 eh = path[depth].p_hdr;
1791 nearex = ex;
1792 goto merge;
1793 }
1794
1795 depth = ext_depth(inode);
1796 eh = path[depth].p_hdr;
1797 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1798 goto has_space;
1799
1800 /* probably next leaf has space for us? */
1801 fex = EXT_LAST_EXTENT(eh);
1802 next = EXT_MAX_BLOCKS;
1803 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1804 next = ext4_ext_next_leaf_block(path);
1805 if (next != EXT_MAX_BLOCKS) {
1806 ext_debug("next leaf block - %u\n", next);
1807 BUG_ON(npath != NULL);
1808 npath = ext4_ext_find_extent(inode, next, NULL);
1809 if (IS_ERR(npath))
1810 return PTR_ERR(npath);
1811 BUG_ON(npath->p_depth != path->p_depth);
1812 eh = npath[depth].p_hdr;
1813 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1814 ext_debug("next leaf isn't full(%d)\n",
1815 le16_to_cpu(eh->eh_entries));
1816 path = npath;
1817 goto has_space;
1818 }
1819 ext_debug("next leaf has no free space(%d,%d)\n",
1820 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1821 }
1822
1823 /*
1824 * There is no free space in the found leaf.
1825 * We're gonna add a new leaf in the tree.
1826 */
1827 if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
1828 flags = EXT4_MB_USE_ROOT_BLOCKS;
1829 err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
1830 if (err)
1831 goto cleanup;
1832 depth = ext_depth(inode);
1833 eh = path[depth].p_hdr;
1834
1835has_space:
1836 nearex = path[depth].p_ext;
1837
1838 err = ext4_ext_get_access(handle, inode, path + depth);
1839 if (err)
1840 goto cleanup;
1841
1842 if (!nearex) {
1843 /* there is no extent in this leaf, create first one */
1844 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
1845 le32_to_cpu(newext->ee_block),
1846 ext4_ext_pblock(newext),
1847 ext4_ext_is_uninitialized(newext),
1848 ext4_ext_get_actual_len(newext));
1849 nearex = EXT_FIRST_EXTENT(eh);
1850 } else {
1851 if (le32_to_cpu(newext->ee_block)
1852 > le32_to_cpu(nearex->ee_block)) {
1853 /* Insert after */
1854 ext_debug("insert %u:%llu:[%d]%d before: "
1855 "nearest %p\n",
1856 le32_to_cpu(newext->ee_block),
1857 ext4_ext_pblock(newext),
1858 ext4_ext_is_uninitialized(newext),
1859 ext4_ext_get_actual_len(newext),
1860 nearex);
1861 nearex++;
1862 } else {
1863 /* Insert before */
1864 BUG_ON(newext->ee_block == nearex->ee_block);
1865 ext_debug("insert %u:%llu:[%d]%d after: "
1866 "nearest %p\n",
1867 le32_to_cpu(newext->ee_block),
1868 ext4_ext_pblock(newext),
1869 ext4_ext_is_uninitialized(newext),
1870 ext4_ext_get_actual_len(newext),
1871 nearex);
1872 }
1873 len = EXT_LAST_EXTENT(eh) - nearex + 1;
1874 if (len > 0) {
1875 ext_debug("insert %u:%llu:[%d]%d: "
1876 "move %d extents from 0x%p to 0x%p\n",
1877 le32_to_cpu(newext->ee_block),
1878 ext4_ext_pblock(newext),
1879 ext4_ext_is_uninitialized(newext),
1880 ext4_ext_get_actual_len(newext),
1881 len, nearex, nearex + 1);
1882 memmove(nearex + 1, nearex,
1883 len * sizeof(struct ext4_extent));
1884 }
1885 }
1886
1887 le16_add_cpu(&eh->eh_entries, 1);
1888 path[depth].p_ext = nearex;
1889 nearex->ee_block = newext->ee_block;
1890 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
1891 nearex->ee_len = newext->ee_len;
1892
1893merge:
1894 /* try to merge extents to the right */
1895 if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
1896 ext4_ext_try_to_merge(inode, path, nearex);
1897
1898 /* try to merge extents to the left */
1899
1900 /* time to correct all indexes above */
1901 err = ext4_ext_correct_indexes(handle, inode, path);
1902 if (err)
1903 goto cleanup;
1904
1905 err = ext4_ext_dirty(handle, inode, path + depth);
1906
1907cleanup:
1908 if (npath) {
1909 ext4_ext_drop_refs(npath);
1910 kfree(npath);
1911 }
1912 ext4_ext_invalidate_cache(inode);
1913 return err;
1914}
1915
1916static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1917 ext4_lblk_t num, ext_prepare_callback func,
1918 void *cbdata)
1919{
1920 struct ext4_ext_path *path = NULL;
1921 struct ext4_ext_cache cbex;
1922 struct ext4_extent *ex;
1923 ext4_lblk_t next, start = 0, end = 0;
1924 ext4_lblk_t last = block + num;
1925 int depth, exists, err = 0;
1926
1927 BUG_ON(func == NULL);
1928 BUG_ON(inode == NULL);
1929
1930 while (block < last && block != EXT_MAX_BLOCKS) {
1931 num = last - block;
1932 /* find extent for this block */
1933 down_read(&EXT4_I(inode)->i_data_sem);
1934 path = ext4_ext_find_extent(inode, block, path);
1935 up_read(&EXT4_I(inode)->i_data_sem);
1936 if (IS_ERR(path)) {
1937 err = PTR_ERR(path);
1938 path = NULL;
1939 break;
1940 }
1941
1942 depth = ext_depth(inode);
1943 if (unlikely(path[depth].p_hdr == NULL)) {
1944 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1945 err = -EIO;
1946 break;
1947 }
1948 ex = path[depth].p_ext;
1949 next = ext4_ext_next_allocated_block(path);
1950
1951 exists = 0;
1952 if (!ex) {
1953 /* there is no extent yet, so try to allocate
1954 * all requested space */
1955 start = block;
1956 end = block + num;
1957 } else if (le32_to_cpu(ex->ee_block) > block) {
1958 /* need to allocate space before found extent */
1959 start = block;
1960 end = le32_to_cpu(ex->ee_block);
1961 if (block + num < end)
1962 end = block + num;
1963 } else if (block >= le32_to_cpu(ex->ee_block)
1964 + ext4_ext_get_actual_len(ex)) {
1965 /* need to allocate space after found extent */
1966 start = block;
1967 end = block + num;
1968 if (end >= next)
1969 end = next;
1970 } else if (block >= le32_to_cpu(ex->ee_block)) {
1971 /*
1972 * some part of requested space is covered
1973 * by found extent
1974 */
1975 start = block;
1976 end = le32_to_cpu(ex->ee_block)
1977 + ext4_ext_get_actual_len(ex);
1978 if (block + num < end)
1979 end = block + num;
1980 exists = 1;
1981 } else {
1982 BUG();
1983 }
1984 BUG_ON(end <= start);
1985
1986 if (!exists) {
1987 cbex.ec_block = start;
1988 cbex.ec_len = end - start;
1989 cbex.ec_start = 0;
1990 } else {
1991 cbex.ec_block = le32_to_cpu(ex->ee_block);
1992 cbex.ec_len = ext4_ext_get_actual_len(ex);
1993 cbex.ec_start = ext4_ext_pblock(ex);
1994 }
1995
1996 if (unlikely(cbex.ec_len == 0)) {
1997 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
1998 err = -EIO;
1999 break;
2000 }
2001 err = func(inode, next, &cbex, ex, cbdata);
2002 ext4_ext_drop_refs(path);
2003
2004 if (err < 0)
2005 break;
2006
2007 if (err == EXT_REPEAT)
2008 continue;
2009 else if (err == EXT_BREAK) {
2010 err = 0;
2011 break;
2012 }
2013
2014 if (ext_depth(inode) != depth) {
2015 /* depth was changed. we have to realloc path */
2016 kfree(path);
2017 path = NULL;
2018 }
2019
2020 block = cbex.ec_block + cbex.ec_len;
2021 }
2022
2023 if (path) {
2024 ext4_ext_drop_refs(path);
2025 kfree(path);
2026 }
2027
2028 return err;
2029}
2030
2031static void
2032ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
2033 __u32 len, ext4_fsblk_t start)
2034{
2035 struct ext4_ext_cache *cex;
2036 BUG_ON(len == 0);
2037 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
2038 trace_ext4_ext_put_in_cache(inode, block, len, start);
2039 cex = &EXT4_I(inode)->i_cached_extent;
2040 cex->ec_block = block;
2041 cex->ec_len = len;
2042 cex->ec_start = start;
2043 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
2044}
2045
2046/*
2047 * ext4_ext_put_gap_in_cache:
2048 * calculate boundaries of the gap that the requested block fits into
2049 * and cache this gap
2050 */
2051static void
2052ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2053 ext4_lblk_t block)
2054{
2055 int depth = ext_depth(inode);
2056 unsigned long len;
2057 ext4_lblk_t lblock;
2058 struct ext4_extent *ex;
2059
2060 ex = path[depth].p_ext;
2061 if (ex == NULL) {
2062 /* there is no extent yet, so gap is [0;-] */
2063 lblock = 0;
2064 len = EXT_MAX_BLOCKS;
2065 ext_debug("cache gap(whole file):");
2066 } else if (block < le32_to_cpu(ex->ee_block)) {
2067 lblock = block;
2068 len = le32_to_cpu(ex->ee_block) - block;
2069 ext_debug("cache gap(before): %u [%u:%u]",
2070 block,
2071 le32_to_cpu(ex->ee_block),
2072 ext4_ext_get_actual_len(ex));
2073 } else if (block >= le32_to_cpu(ex->ee_block)
2074 + ext4_ext_get_actual_len(ex)) {
2075 ext4_lblk_t next;
2076 lblock = le32_to_cpu(ex->ee_block)
2077 + ext4_ext_get_actual_len(ex);
2078
2079 next = ext4_ext_next_allocated_block(path);
2080 ext_debug("cache gap(after): [%u:%u] %u",
2081 le32_to_cpu(ex->ee_block),
2082 ext4_ext_get_actual_len(ex),
2083 block);
2084 BUG_ON(next == lblock);
2085 len = next - lblock;
2086 } else {
2087 lblock = len = 0;
2088 BUG();
2089 }
2090
2091 ext_debug(" -> %u:%lu\n", lblock, len);
2092 ext4_ext_put_in_cache(inode, lblock, len, 0);
2093}
2094
2095/*
2096 * ext4_ext_check_cache()
2097 * Checks to see if the given block is in the cache.
2098 * If it is, the cached extent is stored in the given
2099 * cache extent pointer. If the cached extent is a hole,
2100 * this routine should be used instead of
2101 * ext4_ext_in_cache if the calling function needs to
2102 * know the size of the hole.
2103 *
2104 * @inode: The files inode
2105 * @block: The block to look for in the cache
2106 * @ex: Pointer where the cached extent will be stored
2107 * if it contains block
2108 *
2109 * Return 0 if cache is invalid; 1 if the cache is valid
2110 */
2111static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block,
2112 struct ext4_ext_cache *ex){
2113 struct ext4_ext_cache *cex;
2114 struct ext4_sb_info *sbi;
2115 int ret = 0;
2116
2117 /*
2118 * We borrow i_block_reservation_lock to protect i_cached_extent
2119 */
2120 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
2121 cex = &EXT4_I(inode)->i_cached_extent;
2122 sbi = EXT4_SB(inode->i_sb);
2123
2124 /* has cache valid data? */
2125 if (cex->ec_len == 0)
2126 goto errout;
2127
2128 if (in_range(block, cex->ec_block, cex->ec_len)) {
2129 memcpy(ex, cex, sizeof(struct ext4_ext_cache));
2130 ext_debug("%u cached by %u:%u:%llu\n",
2131 block,
2132 cex->ec_block, cex->ec_len, cex->ec_start);
2133 ret = 1;
2134 }
2135errout:
2136 trace_ext4_ext_in_cache(inode, block, ret);
2137 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
2138 return ret;
2139}
2140
2141/*
2142 * ext4_ext_in_cache()
2143 * Checks to see if the given block is in the cache.
2144 * If it is, the cached extent is stored in the given
2145 * extent pointer.
2146 *
2147 * @inode: The files inode
2148 * @block: The block to look for in the cache
2149 * @ex: Pointer where the cached extent will be stored
2150 * if it contains block
2151 *
2152 * Return 0 if cache is invalid; 1 if the cache is valid
2153 */
2154static int
2155ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
2156 struct ext4_extent *ex)
2157{
2158 struct ext4_ext_cache cex;
2159 int ret = 0;
2160
2161 if (ext4_ext_check_cache(inode, block, &cex)) {
2162 ex->ee_block = cpu_to_le32(cex.ec_block);
2163 ext4_ext_store_pblock(ex, cex.ec_start);
2164 ex->ee_len = cpu_to_le16(cex.ec_len);
2165 ret = 1;
2166 }
2167
2168 return ret;
2169}
2170
2171
2172/*
2173 * ext4_ext_rm_idx:
2174 * removes index from the index block.
2175 */
2176static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2177 struct ext4_ext_path *path)
2178{
2179 int err;
2180 ext4_fsblk_t leaf;
2181
2182 /* free index block */
2183 path--;
2184 leaf = ext4_idx_pblock(path->p_idx);
2185 if (unlikely(path->p_hdr->eh_entries == 0)) {
2186 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2187 return -EIO;
2188 }
2189 err = ext4_ext_get_access(handle, inode, path);
2190 if (err)
2191 return err;
2192
2193 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2194 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2195 len *= sizeof(struct ext4_extent_idx);
2196 memmove(path->p_idx, path->p_idx + 1, len);
2197 }
2198
2199 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2200 err = ext4_ext_dirty(handle, inode, path);
2201 if (err)
2202 return err;
2203 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2204 trace_ext4_ext_rm_idx(inode, leaf);
2205
2206 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2207 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2208 return err;
2209}
2210
2211/*
2212 * ext4_ext_calc_credits_for_single_extent:
2213 * This routine returns max. credits that needed to insert an extent
2214 * to the extent tree.
2215 * When pass the actual path, the caller should calculate credits
2216 * under i_data_sem.
2217 */
2218int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2219 struct ext4_ext_path *path)
2220{
2221 if (path) {
2222 int depth = ext_depth(inode);
2223 int ret = 0;
2224
2225 /* probably there is space in leaf? */
2226 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2227 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2228
2229 /*
2230 * There are some space in the leaf tree, no
2231 * need to account for leaf block credit
2232 *
2233 * bitmaps and block group descriptor blocks
2234 * and other metadata blocks still need to be
2235 * accounted.
2236 */
2237 /* 1 bitmap, 1 block group descriptor */
2238 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2239 return ret;
2240 }
2241 }
2242
2243 return ext4_chunk_trans_blocks(inode, nrblocks);
2244}
2245
2246/*
2247 * How many index/leaf blocks need to change/allocate to modify nrblocks?
2248 *
2249 * if nrblocks are fit in a single extent (chunk flag is 1), then
2250 * in the worse case, each tree level index/leaf need to be changed
2251 * if the tree split due to insert a new extent, then the old tree
2252 * index/leaf need to be updated too
2253 *
2254 * If the nrblocks are discontiguous, they could cause
2255 * the whole tree split more than once, but this is really rare.
2256 */
2257int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2258{
2259 int index;
2260 int depth = ext_depth(inode);
2261
2262 if (chunk)
2263 index = depth * 2;
2264 else
2265 index = depth * 3;
2266
2267 return index;
2268}
2269
2270static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2271 struct ext4_extent *ex,
2272 ext4_fsblk_t *partial_cluster,
2273 ext4_lblk_t from, ext4_lblk_t to)
2274{
2275 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2276 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2277 ext4_fsblk_t pblk;
2278 int flags = EXT4_FREE_BLOCKS_FORGET;
2279
2280 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2281 flags |= EXT4_FREE_BLOCKS_METADATA;
2282 /*
2283 * For bigalloc file systems, we never free a partial cluster
2284 * at the beginning of the extent. Instead, we make a note
2285 * that we tried freeing the cluster, and check to see if we
2286 * need to free it on a subsequent call to ext4_remove_blocks,
2287 * or at the end of the ext4_truncate() operation.
2288 */
2289 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2290
2291 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2292 /*
2293 * If we have a partial cluster, and it's different from the
2294 * cluster of the last block, we need to explicitly free the
2295 * partial cluster here.
2296 */
2297 pblk = ext4_ext_pblock(ex) + ee_len - 1;
2298 if (*partial_cluster && (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2299 ext4_free_blocks(handle, inode, NULL,
2300 EXT4_C2B(sbi, *partial_cluster),
2301 sbi->s_cluster_ratio, flags);
2302 *partial_cluster = 0;
2303 }
2304
2305#ifdef EXTENTS_STATS
2306 {
2307 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2308 spin_lock(&sbi->s_ext_stats_lock);
2309 sbi->s_ext_blocks += ee_len;
2310 sbi->s_ext_extents++;
2311 if (ee_len < sbi->s_ext_min)
2312 sbi->s_ext_min = ee_len;
2313 if (ee_len > sbi->s_ext_max)
2314 sbi->s_ext_max = ee_len;
2315 if (ext_depth(inode) > sbi->s_depth_max)
2316 sbi->s_depth_max = ext_depth(inode);
2317 spin_unlock(&sbi->s_ext_stats_lock);
2318 }
2319#endif
2320 if (from >= le32_to_cpu(ex->ee_block)
2321 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2322 /* tail removal */
2323 ext4_lblk_t num;
2324
2325 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2326 pblk = ext4_ext_pblock(ex) + ee_len - num;
2327 ext_debug("free last %u blocks starting %llu\n", num, pblk);
2328 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2329 /*
2330 * If the block range to be freed didn't start at the
2331 * beginning of a cluster, and we removed the entire
2332 * extent, save the partial cluster here, since we
2333 * might need to delete if we determine that the
2334 * truncate operation has removed all of the blocks in
2335 * the cluster.
2336 */
2337 if (pblk & (sbi->s_cluster_ratio - 1) &&
2338 (ee_len == num))
2339 *partial_cluster = EXT4_B2C(sbi, pblk);
2340 else
2341 *partial_cluster = 0;
2342 } else if (from == le32_to_cpu(ex->ee_block)
2343 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2344 /* head removal */
2345 ext4_lblk_t num;
2346 ext4_fsblk_t start;
2347
2348 num = to - from;
2349 start = ext4_ext_pblock(ex);
2350
2351 ext_debug("free first %u blocks starting %llu\n", num, start);
2352 ext4_free_blocks(handle, inode, NULL, start, num, flags);
2353
2354 } else {
2355 printk(KERN_INFO "strange request: removal(2) "
2356 "%u-%u from %u:%u\n",
2357 from, to, le32_to_cpu(ex->ee_block), ee_len);
2358 }
2359 return 0;
2360}
2361
2362
2363/*
2364 * ext4_ext_rm_leaf() Removes the extents associated with the
2365 * blocks appearing between "start" and "end", and splits the extents
2366 * if "start" and "end" appear in the same extent
2367 *
2368 * @handle: The journal handle
2369 * @inode: The files inode
2370 * @path: The path to the leaf
2371 * @start: The first block to remove
2372 * @end: The last block to remove
2373 */
2374static int
2375ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2376 struct ext4_ext_path *path, ext4_fsblk_t *partial_cluster,
2377 ext4_lblk_t start, ext4_lblk_t end)
2378{
2379 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2380 int err = 0, correct_index = 0;
2381 int depth = ext_depth(inode), credits;
2382 struct ext4_extent_header *eh;
2383 ext4_lblk_t a, b;
2384 unsigned num;
2385 ext4_lblk_t ex_ee_block;
2386 unsigned short ex_ee_len;
2387 unsigned uninitialized = 0;
2388 struct ext4_extent *ex;
2389
2390 /* the header must be checked already in ext4_ext_remove_space() */
2391 ext_debug("truncate since %u in leaf to %u\n", start, end);
2392 if (!path[depth].p_hdr)
2393 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2394 eh = path[depth].p_hdr;
2395 if (unlikely(path[depth].p_hdr == NULL)) {
2396 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2397 return -EIO;
2398 }
2399 /* find where to start removing */
2400 ex = EXT_LAST_EXTENT(eh);
2401
2402 ex_ee_block = le32_to_cpu(ex->ee_block);
2403 ex_ee_len = ext4_ext_get_actual_len(ex);
2404
2405 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2406
2407 while (ex >= EXT_FIRST_EXTENT(eh) &&
2408 ex_ee_block + ex_ee_len > start) {
2409
2410 if (ext4_ext_is_uninitialized(ex))
2411 uninitialized = 1;
2412 else
2413 uninitialized = 0;
2414
2415 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2416 uninitialized, ex_ee_len);
2417 path[depth].p_ext = ex;
2418
2419 a = ex_ee_block > start ? ex_ee_block : start;
2420 b = ex_ee_block+ex_ee_len - 1 < end ?
2421 ex_ee_block+ex_ee_len - 1 : end;
2422
2423 ext_debug(" border %u:%u\n", a, b);
2424
2425 /* If this extent is beyond the end of the hole, skip it */
2426 if (end < ex_ee_block) {
2427 ex--;
2428 ex_ee_block = le32_to_cpu(ex->ee_block);
2429 ex_ee_len = ext4_ext_get_actual_len(ex);
2430 continue;
2431 } else if (b != ex_ee_block + ex_ee_len - 1) {
2432 EXT4_ERROR_INODE(inode,
2433 "can not handle truncate %u:%u "
2434 "on extent %u:%u",
2435 start, end, ex_ee_block,
2436 ex_ee_block + ex_ee_len - 1);
2437 err = -EIO;
2438 goto out;
2439 } else if (a != ex_ee_block) {
2440 /* remove tail of the extent */
2441 num = a - ex_ee_block;
2442 } else {
2443 /* remove whole extent: excellent! */
2444 num = 0;
2445 }
2446 /*
2447 * 3 for leaf, sb, and inode plus 2 (bmap and group
2448 * descriptor) for each block group; assume two block
2449 * groups plus ex_ee_len/blocks_per_block_group for
2450 * the worst case
2451 */
2452 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2453 if (ex == EXT_FIRST_EXTENT(eh)) {
2454 correct_index = 1;
2455 credits += (ext_depth(inode)) + 1;
2456 }
2457 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2458
2459 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2460 if (err)
2461 goto out;
2462
2463 err = ext4_ext_get_access(handle, inode, path + depth);
2464 if (err)
2465 goto out;
2466
2467 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2468 a, b);
2469 if (err)
2470 goto out;
2471
2472 if (num == 0)
2473 /* this extent is removed; mark slot entirely unused */
2474 ext4_ext_store_pblock(ex, 0);
2475
2476 ex->ee_len = cpu_to_le16(num);
2477 /*
2478 * Do not mark uninitialized if all the blocks in the
2479 * extent have been removed.
2480 */
2481 if (uninitialized && num)
2482 ext4_ext_mark_uninitialized(ex);
2483 /*
2484 * If the extent was completely released,
2485 * we need to remove it from the leaf
2486 */
2487 if (num == 0) {
2488 if (end != EXT_MAX_BLOCKS - 1) {
2489 /*
2490 * For hole punching, we need to scoot all the
2491 * extents up when an extent is removed so that
2492 * we dont have blank extents in the middle
2493 */
2494 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2495 sizeof(struct ext4_extent));
2496
2497 /* Now get rid of the one at the end */
2498 memset(EXT_LAST_EXTENT(eh), 0,
2499 sizeof(struct ext4_extent));
2500 }
2501 le16_add_cpu(&eh->eh_entries, -1);
2502 } else
2503 *partial_cluster = 0;
2504
2505 err = ext4_ext_dirty(handle, inode, path + depth);
2506 if (err)
2507 goto out;
2508
2509 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2510 ext4_ext_pblock(ex));
2511 ex--;
2512 ex_ee_block = le32_to_cpu(ex->ee_block);
2513 ex_ee_len = ext4_ext_get_actual_len(ex);
2514 }
2515
2516 if (correct_index && eh->eh_entries)
2517 err = ext4_ext_correct_indexes(handle, inode, path);
2518
2519 /*
2520 * If there is still a entry in the leaf node, check to see if
2521 * it references the partial cluster. This is the only place
2522 * where it could; if it doesn't, we can free the cluster.
2523 */
2524 if (*partial_cluster && ex >= EXT_FIRST_EXTENT(eh) &&
2525 (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2526 *partial_cluster)) {
2527 int flags = EXT4_FREE_BLOCKS_FORGET;
2528
2529 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2530 flags |= EXT4_FREE_BLOCKS_METADATA;
2531
2532 ext4_free_blocks(handle, inode, NULL,
2533 EXT4_C2B(sbi, *partial_cluster),
2534 sbi->s_cluster_ratio, flags);
2535 *partial_cluster = 0;
2536 }
2537
2538 /* if this leaf is free, then we should
2539 * remove it from index block above */
2540 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2541 err = ext4_ext_rm_idx(handle, inode, path + depth);
2542
2543out:
2544 return err;
2545}
2546
2547/*
2548 * ext4_ext_more_to_rm:
2549 * returns 1 if current index has to be freed (even partial)
2550 */
2551static int
2552ext4_ext_more_to_rm(struct ext4_ext_path *path)
2553{
2554 BUG_ON(path->p_idx == NULL);
2555
2556 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2557 return 0;
2558
2559 /*
2560 * if truncate on deeper level happened, it wasn't partial,
2561 * so we have to consider current index for truncation
2562 */
2563 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2564 return 0;
2565 return 1;
2566}
2567
2568static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2569 ext4_lblk_t end)
2570{
2571 struct super_block *sb = inode->i_sb;
2572 int depth = ext_depth(inode);
2573 struct ext4_ext_path *path = NULL;
2574 ext4_fsblk_t partial_cluster = 0;
2575 handle_t *handle;
2576 int i = 0, err;
2577
2578 ext_debug("truncate since %u to %u\n", start, end);
2579
2580 /* probably first extent we're gonna free will be last in block */
2581 handle = ext4_journal_start(inode, depth + 1);
2582 if (IS_ERR(handle))
2583 return PTR_ERR(handle);
2584
2585again:
2586 ext4_ext_invalidate_cache(inode);
2587
2588 trace_ext4_ext_remove_space(inode, start, depth);
2589
2590 /*
2591 * Check if we are removing extents inside the extent tree. If that
2592 * is the case, we are going to punch a hole inside the extent tree
2593 * so we have to check whether we need to split the extent covering
2594 * the last block to remove so we can easily remove the part of it
2595 * in ext4_ext_rm_leaf().
2596 */
2597 if (end < EXT_MAX_BLOCKS - 1) {
2598 struct ext4_extent *ex;
2599 ext4_lblk_t ee_block;
2600
2601 /* find extent for this block */
2602 path = ext4_ext_find_extent(inode, end, NULL);
2603 if (IS_ERR(path)) {
2604 ext4_journal_stop(handle);
2605 return PTR_ERR(path);
2606 }
2607 depth = ext_depth(inode);
2608 ex = path[depth].p_ext;
2609 if (!ex) {
2610 ext4_ext_drop_refs(path);
2611 kfree(path);
2612 path = NULL;
2613 goto cont;
2614 }
2615
2616 ee_block = le32_to_cpu(ex->ee_block);
2617
2618 /*
2619 * See if the last block is inside the extent, if so split
2620 * the extent at 'end' block so we can easily remove the
2621 * tail of the first part of the split extent in
2622 * ext4_ext_rm_leaf().
2623 */
2624 if (end >= ee_block &&
2625 end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2626 int split_flag = 0;
2627
2628 if (ext4_ext_is_uninitialized(ex))
2629 split_flag = EXT4_EXT_MARK_UNINIT1 |
2630 EXT4_EXT_MARK_UNINIT2;
2631
2632 /*
2633 * Split the extent in two so that 'end' is the last
2634 * block in the first new extent
2635 */
2636 err = ext4_split_extent_at(handle, inode, path,
2637 end + 1, split_flag,
2638 EXT4_GET_BLOCKS_PRE_IO |
2639 EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
2640
2641 if (err < 0)
2642 goto out;
2643 }
2644 }
2645cont:
2646
2647 /*
2648 * We start scanning from right side, freeing all the blocks
2649 * after i_size and walking into the tree depth-wise.
2650 */
2651 depth = ext_depth(inode);
2652 if (path) {
2653 int k = i = depth;
2654 while (--k > 0)
2655 path[k].p_block =
2656 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2657 } else {
2658 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2659 GFP_NOFS);
2660 if (path == NULL) {
2661 ext4_journal_stop(handle);
2662 return -ENOMEM;
2663 }
2664 path[0].p_depth = depth;
2665 path[0].p_hdr = ext_inode_hdr(inode);
2666 i = 0;
2667
2668 if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2669 err = -EIO;
2670 goto out;
2671 }
2672 }
2673 err = 0;
2674
2675 while (i >= 0 && err == 0) {
2676 if (i == depth) {
2677 /* this is leaf block */
2678 err = ext4_ext_rm_leaf(handle, inode, path,
2679 &partial_cluster, start,
2680 end);
2681 /* root level has p_bh == NULL, brelse() eats this */
2682 brelse(path[i].p_bh);
2683 path[i].p_bh = NULL;
2684 i--;
2685 continue;
2686 }
2687
2688 /* this is index block */
2689 if (!path[i].p_hdr) {
2690 ext_debug("initialize header\n");
2691 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2692 }
2693
2694 if (!path[i].p_idx) {
2695 /* this level hasn't been touched yet */
2696 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2697 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2698 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2699 path[i].p_hdr,
2700 le16_to_cpu(path[i].p_hdr->eh_entries));
2701 } else {
2702 /* we were already here, see at next index */
2703 path[i].p_idx--;
2704 }
2705
2706 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2707 i, EXT_FIRST_INDEX(path[i].p_hdr),
2708 path[i].p_idx);
2709 if (ext4_ext_more_to_rm(path + i)) {
2710 struct buffer_head *bh;
2711 /* go to the next level */
2712 ext_debug("move to level %d (block %llu)\n",
2713 i + 1, ext4_idx_pblock(path[i].p_idx));
2714 memset(path + i + 1, 0, sizeof(*path));
2715 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
2716 if (!bh) {
2717 /* should we reset i_size? */
2718 err = -EIO;
2719 break;
2720 }
2721 if (WARN_ON(i + 1 > depth)) {
2722 err = -EIO;
2723 break;
2724 }
2725 if (ext4_ext_check_block(inode, ext_block_hdr(bh),
2726 depth - i - 1, bh)) {
2727 err = -EIO;
2728 break;
2729 }
2730 path[i + 1].p_bh = bh;
2731
2732 /* save actual number of indexes since this
2733 * number is changed at the next iteration */
2734 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2735 i++;
2736 } else {
2737 /* we finished processing this index, go up */
2738 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2739 /* index is empty, remove it;
2740 * handle must be already prepared by the
2741 * truncatei_leaf() */
2742 err = ext4_ext_rm_idx(handle, inode, path + i);
2743 }
2744 /* root level has p_bh == NULL, brelse() eats this */
2745 brelse(path[i].p_bh);
2746 path[i].p_bh = NULL;
2747 i--;
2748 ext_debug("return to level %d\n", i);
2749 }
2750 }
2751
2752 trace_ext4_ext_remove_space_done(inode, start, depth, partial_cluster,
2753 path->p_hdr->eh_entries);
2754
2755 /* If we still have something in the partial cluster and we have removed
2756 * even the first extent, then we should free the blocks in the partial
2757 * cluster as well. */
2758 if (partial_cluster && path->p_hdr->eh_entries == 0) {
2759 int flags = EXT4_FREE_BLOCKS_FORGET;
2760
2761 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2762 flags |= EXT4_FREE_BLOCKS_METADATA;
2763
2764 ext4_free_blocks(handle, inode, NULL,
2765 EXT4_C2B(EXT4_SB(sb), partial_cluster),
2766 EXT4_SB(sb)->s_cluster_ratio, flags);
2767 partial_cluster = 0;
2768 }
2769
2770 /* TODO: flexible tree reduction should be here */
2771 if (path->p_hdr->eh_entries == 0) {
2772 /*
2773 * truncate to zero freed all the tree,
2774 * so we need to correct eh_depth
2775 */
2776 err = ext4_ext_get_access(handle, inode, path);
2777 if (err == 0) {
2778 ext_inode_hdr(inode)->eh_depth = 0;
2779 ext_inode_hdr(inode)->eh_max =
2780 cpu_to_le16(ext4_ext_space_root(inode, 0));
2781 err = ext4_ext_dirty(handle, inode, path);
2782 }
2783 }
2784out:
2785 ext4_ext_drop_refs(path);
2786 kfree(path);
2787 if (err == -EAGAIN) {
2788 path = NULL;
2789 goto again;
2790 }
2791 ext4_journal_stop(handle);
2792
2793 return err;
2794}
2795
2796/*
2797 * called at mount time
2798 */
2799void ext4_ext_init(struct super_block *sb)
2800{
2801 /*
2802 * possible initialization would be here
2803 */
2804
2805 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2806#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
2807 printk(KERN_INFO "EXT4-fs: file extents enabled"
2808#ifdef AGGRESSIVE_TEST
2809 ", aggressive tests"
2810#endif
2811#ifdef CHECK_BINSEARCH
2812 ", check binsearch"
2813#endif
2814#ifdef EXTENTS_STATS
2815 ", stats"
2816#endif
2817 "\n");
2818#endif
2819#ifdef EXTENTS_STATS
2820 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2821 EXT4_SB(sb)->s_ext_min = 1 << 30;
2822 EXT4_SB(sb)->s_ext_max = 0;
2823#endif
2824 }
2825}
2826
2827/*
2828 * called at umount time
2829 */
2830void ext4_ext_release(struct super_block *sb)
2831{
2832 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2833 return;
2834
2835#ifdef EXTENTS_STATS
2836 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2837 struct ext4_sb_info *sbi = EXT4_SB(sb);
2838 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2839 sbi->s_ext_blocks, sbi->s_ext_extents,
2840 sbi->s_ext_blocks / sbi->s_ext_extents);
2841 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2842 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2843 }
2844#endif
2845}
2846
2847/* FIXME!! we need to try to merge to left or right after zero-out */
2848static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2849{
2850 ext4_fsblk_t ee_pblock;
2851 unsigned int ee_len;
2852 int ret;
2853
2854 ee_len = ext4_ext_get_actual_len(ex);
2855 ee_pblock = ext4_ext_pblock(ex);
2856
2857 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
2858 if (ret > 0)
2859 ret = 0;
2860
2861 return ret;
2862}
2863
2864/*
2865 * ext4_split_extent_at() splits an extent at given block.
2866 *
2867 * @handle: the journal handle
2868 * @inode: the file inode
2869 * @path: the path to the extent
2870 * @split: the logical block where the extent is splitted.
2871 * @split_flags: indicates if the extent could be zeroout if split fails, and
2872 * the states(init or uninit) of new extents.
2873 * @flags: flags used to insert new extent to extent tree.
2874 *
2875 *
2876 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
2877 * of which are deterimined by split_flag.
2878 *
2879 * There are two cases:
2880 * a> the extent are splitted into two extent.
2881 * b> split is not needed, and just mark the extent.
2882 *
2883 * return 0 on success.
2884 */
2885static int ext4_split_extent_at(handle_t *handle,
2886 struct inode *inode,
2887 struct ext4_ext_path *path,
2888 ext4_lblk_t split,
2889 int split_flag,
2890 int flags)
2891{
2892 ext4_fsblk_t newblock;
2893 ext4_lblk_t ee_block;
2894 struct ext4_extent *ex, newex, orig_ex;
2895 struct ext4_extent *ex2 = NULL;
2896 unsigned int ee_len, depth;
2897 int err = 0;
2898
2899 ext_debug("ext4_split_extents_at: inode %lu, logical"
2900 "block %llu\n", inode->i_ino, (unsigned long long)split);
2901
2902 ext4_ext_show_leaf(inode, path);
2903
2904 depth = ext_depth(inode);
2905 ex = path[depth].p_ext;
2906 ee_block = le32_to_cpu(ex->ee_block);
2907 ee_len = ext4_ext_get_actual_len(ex);
2908 newblock = split - ee_block + ext4_ext_pblock(ex);
2909
2910 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
2911
2912 err = ext4_ext_get_access(handle, inode, path + depth);
2913 if (err)
2914 goto out;
2915
2916 if (split == ee_block) {
2917 /*
2918 * case b: block @split is the block that the extent begins with
2919 * then we just change the state of the extent, and splitting
2920 * is not needed.
2921 */
2922 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2923 ext4_ext_mark_uninitialized(ex);
2924 else
2925 ext4_ext_mark_initialized(ex);
2926
2927 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
2928 ext4_ext_try_to_merge(inode, path, ex);
2929
2930 err = ext4_ext_dirty(handle, inode, path + depth);
2931 goto out;
2932 }
2933
2934 /* case a */
2935 memcpy(&orig_ex, ex, sizeof(orig_ex));
2936 ex->ee_len = cpu_to_le16(split - ee_block);
2937 if (split_flag & EXT4_EXT_MARK_UNINIT1)
2938 ext4_ext_mark_uninitialized(ex);
2939
2940 /*
2941 * path may lead to new leaf, not to original leaf any more
2942 * after ext4_ext_insert_extent() returns,
2943 */
2944 err = ext4_ext_dirty(handle, inode, path + depth);
2945 if (err)
2946 goto fix_extent_len;
2947
2948 ex2 = &newex;
2949 ex2->ee_block = cpu_to_le32(split);
2950 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
2951 ext4_ext_store_pblock(ex2, newblock);
2952 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2953 ext4_ext_mark_uninitialized(ex2);
2954
2955 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2956 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2957 err = ext4_ext_zeroout(inode, &orig_ex);
2958 if (err)
2959 goto fix_extent_len;
2960 /* update the extent length and mark as initialized */
2961 ex->ee_len = cpu_to_le16(ee_len);
2962 ext4_ext_try_to_merge(inode, path, ex);
2963 err = ext4_ext_dirty(handle, inode, path + depth);
2964 goto out;
2965 } else if (err)
2966 goto fix_extent_len;
2967
2968out:
2969 ext4_ext_show_leaf(inode, path);
2970 return err;
2971
2972fix_extent_len:
2973 ex->ee_len = orig_ex.ee_len;
2974 ext4_ext_dirty(handle, inode, path + depth);
2975 return err;
2976}
2977
2978/*
2979 * ext4_split_extents() splits an extent and mark extent which is covered
2980 * by @map as split_flags indicates
2981 *
2982 * It may result in splitting the extent into multiple extents (upto three)
2983 * There are three possibilities:
2984 * a> There is no split required
2985 * b> Splits in two extents: Split is happening at either end of the extent
2986 * c> Splits in three extents: Somone is splitting in middle of the extent
2987 *
2988 */
2989static int ext4_split_extent(handle_t *handle,
2990 struct inode *inode,
2991 struct ext4_ext_path *path,
2992 struct ext4_map_blocks *map,
2993 int split_flag,
2994 int flags)
2995{
2996 ext4_lblk_t ee_block;
2997 struct ext4_extent *ex;
2998 unsigned int ee_len, depth;
2999 int err = 0;
3000 int uninitialized;
3001 int split_flag1, flags1;
3002
3003 depth = ext_depth(inode);
3004 ex = path[depth].p_ext;
3005 ee_block = le32_to_cpu(ex->ee_block);
3006 ee_len = ext4_ext_get_actual_len(ex);
3007 uninitialized = ext4_ext_is_uninitialized(ex);
3008
3009 if (map->m_lblk + map->m_len < ee_block + ee_len) {
3010 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
3011 EXT4_EXT_MAY_ZEROOUT : 0;
3012 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3013 if (uninitialized)
3014 split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
3015 EXT4_EXT_MARK_UNINIT2;
3016 err = ext4_split_extent_at(handle, inode, path,
3017 map->m_lblk + map->m_len, split_flag1, flags1);
3018 if (err)
3019 goto out;
3020 }
3021
3022 ext4_ext_drop_refs(path);
3023 path = ext4_ext_find_extent(inode, map->m_lblk, path);
3024 if (IS_ERR(path))
3025 return PTR_ERR(path);
3026
3027 if (map->m_lblk >= ee_block) {
3028 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
3029 EXT4_EXT_MAY_ZEROOUT : 0;
3030 if (uninitialized)
3031 split_flag1 |= EXT4_EXT_MARK_UNINIT1;
3032 if (split_flag & EXT4_EXT_MARK_UNINIT2)
3033 split_flag1 |= EXT4_EXT_MARK_UNINIT2;
3034 err = ext4_split_extent_at(handle, inode, path,
3035 map->m_lblk, split_flag1, flags);
3036 if (err)
3037 goto out;
3038 }
3039
3040 ext4_ext_show_leaf(inode, path);
3041out:
3042 return err ? err : map->m_len;
3043}
3044
3045#define EXT4_EXT_ZERO_LEN 7
3046/*
3047 * This function is called by ext4_ext_map_blocks() if someone tries to write
3048 * to an uninitialized extent. It may result in splitting the uninitialized
3049 * extent into multiple extents (up to three - one initialized and two
3050 * uninitialized).
3051 * There are three possibilities:
3052 * a> There is no split required: Entire extent should be initialized
3053 * b> Splits in two extents: Write is happening at either end of the extent
3054 * c> Splits in three extents: Somone is writing in middle of the extent
3055 *
3056 * Pre-conditions:
3057 * - The extent pointed to by 'path' is uninitialized.
3058 * - The extent pointed to by 'path' contains a superset
3059 * of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3060 *
3061 * Post-conditions on success:
3062 * - the returned value is the number of blocks beyond map->l_lblk
3063 * that are allocated and initialized.
3064 * It is guaranteed to be >= map->m_len.
3065 */
3066static int ext4_ext_convert_to_initialized(handle_t *handle,
3067 struct inode *inode,
3068 struct ext4_map_blocks *map,
3069 struct ext4_ext_path *path)
3070{
3071 struct ext4_extent_header *eh;
3072 struct ext4_map_blocks split_map;
3073 struct ext4_extent zero_ex;
3074 struct ext4_extent *ex;
3075 ext4_lblk_t ee_block, eof_block;
3076 unsigned int ee_len, depth;
3077 int allocated;
3078 int err = 0;
3079 int split_flag = 0;
3080
3081 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3082 "block %llu, max_blocks %u\n", inode->i_ino,
3083 (unsigned long long)map->m_lblk, map->m_len);
3084
3085 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3086 inode->i_sb->s_blocksize_bits;
3087 if (eof_block < map->m_lblk + map->m_len)
3088 eof_block = map->m_lblk + map->m_len;
3089
3090 depth = ext_depth(inode);
3091 eh = path[depth].p_hdr;
3092 ex = path[depth].p_ext;
3093 ee_block = le32_to_cpu(ex->ee_block);
3094 ee_len = ext4_ext_get_actual_len(ex);
3095 allocated = ee_len - (map->m_lblk - ee_block);
3096
3097 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3098
3099 /* Pre-conditions */
3100 BUG_ON(!ext4_ext_is_uninitialized(ex));
3101 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3102
3103 /*
3104 * Attempt to transfer newly initialized blocks from the currently
3105 * uninitialized extent to its left neighbor. This is much cheaper
3106 * than an insertion followed by a merge as those involve costly
3107 * memmove() calls. This is the common case in steady state for
3108 * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append
3109 * writes.
3110 *
3111 * Limitations of the current logic:
3112 * - L1: we only deal with writes at the start of the extent.
3113 * The approach could be extended to writes at the end
3114 * of the extent but this scenario was deemed less common.
3115 * - L2: we do not deal with writes covering the whole extent.
3116 * This would require removing the extent if the transfer
3117 * is possible.
3118 * - L3: we only attempt to merge with an extent stored in the
3119 * same extent tree node.
3120 */
3121 if ((map->m_lblk == ee_block) && /*L1*/
3122 (map->m_len < ee_len) && /*L2*/
3123 (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/
3124 struct ext4_extent *prev_ex;
3125 ext4_lblk_t prev_lblk;
3126 ext4_fsblk_t prev_pblk, ee_pblk;
3127 unsigned int prev_len, write_len;
3128
3129 prev_ex = ex - 1;
3130 prev_lblk = le32_to_cpu(prev_ex->ee_block);
3131 prev_len = ext4_ext_get_actual_len(prev_ex);
3132 prev_pblk = ext4_ext_pblock(prev_ex);
3133 ee_pblk = ext4_ext_pblock(ex);
3134 write_len = map->m_len;
3135
3136 /*
3137 * A transfer of blocks from 'ex' to 'prev_ex' is allowed
3138 * upon those conditions:
3139 * - C1: prev_ex is initialized,
3140 * - C2: prev_ex is logically abutting ex,
3141 * - C3: prev_ex is physically abutting ex,
3142 * - C4: prev_ex can receive the additional blocks without
3143 * overflowing the (initialized) length limit.
3144 */
3145 if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/
3146 ((prev_lblk + prev_len) == ee_block) && /*C2*/
3147 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/
3148 (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/
3149 err = ext4_ext_get_access(handle, inode, path + depth);
3150 if (err)
3151 goto out;
3152
3153 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3154 map, ex, prev_ex);
3155
3156 /* Shift the start of ex by 'write_len' blocks */
3157 ex->ee_block = cpu_to_le32(ee_block + write_len);
3158 ext4_ext_store_pblock(ex, ee_pblk + write_len);
3159 ex->ee_len = cpu_to_le16(ee_len - write_len);
3160 ext4_ext_mark_uninitialized(ex); /* Restore the flag */
3161
3162 /* Extend prev_ex by 'write_len' blocks */
3163 prev_ex->ee_len = cpu_to_le16(prev_len + write_len);
3164
3165 /* Mark the block containing both extents as dirty */
3166 ext4_ext_dirty(handle, inode, path + depth);
3167
3168 /* Update path to point to the right extent */
3169 path[depth].p_ext = prev_ex;
3170
3171 /* Result: number of initialized blocks past m_lblk */
3172 allocated = write_len;
3173 goto out;
3174 }
3175 }
3176
3177 WARN_ON(map->m_lblk < ee_block);
3178 /*
3179 * It is safe to convert extent to initialized via explicit
3180 * zeroout only if extent is fully insde i_size or new_size.
3181 */
3182 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3183
3184 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
3185 if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
3186 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3187 err = ext4_ext_zeroout(inode, ex);
3188 if (err)
3189 goto out;
3190
3191 err = ext4_ext_get_access(handle, inode, path + depth);
3192 if (err)
3193 goto out;
3194 ext4_ext_mark_initialized(ex);
3195 ext4_ext_try_to_merge(inode, path, ex);
3196 err = ext4_ext_dirty(handle, inode, path + depth);
3197 goto out;
3198 }
3199
3200 /*
3201 * four cases:
3202 * 1. split the extent into three extents.
3203 * 2. split the extent into two extents, zeroout the first half.
3204 * 3. split the extent into two extents, zeroout the second half.
3205 * 4. split the extent into two extents with out zeroout.
3206 */
3207 split_map.m_lblk = map->m_lblk;
3208 split_map.m_len = map->m_len;
3209
3210 if (allocated > map->m_len) {
3211 if (allocated <= EXT4_EXT_ZERO_LEN &&
3212 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3213 /* case 3 */
3214 zero_ex.ee_block =
3215 cpu_to_le32(map->m_lblk);
3216 zero_ex.ee_len = cpu_to_le16(allocated);
3217 ext4_ext_store_pblock(&zero_ex,
3218 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3219 err = ext4_ext_zeroout(inode, &zero_ex);
3220 if (err)
3221 goto out;
3222 split_map.m_lblk = map->m_lblk;
3223 split_map.m_len = allocated;
3224 } else if ((map->m_lblk - ee_block + map->m_len <
3225 EXT4_EXT_ZERO_LEN) &&
3226 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3227 /* case 2 */
3228 if (map->m_lblk != ee_block) {
3229 zero_ex.ee_block = ex->ee_block;
3230 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3231 ee_block);
3232 ext4_ext_store_pblock(&zero_ex,
3233 ext4_ext_pblock(ex));
3234 err = ext4_ext_zeroout(inode, &zero_ex);
3235 if (err)
3236 goto out;
3237 }
3238
3239 split_map.m_lblk = ee_block;
3240 split_map.m_len = map->m_lblk - ee_block + map->m_len;
3241 allocated = map->m_len;
3242 }
3243 }
3244
3245 allocated = ext4_split_extent(handle, inode, path,
3246 &split_map, split_flag, 0);
3247 if (allocated < 0)
3248 err = allocated;
3249
3250out:
3251 return err ? err : allocated;
3252}
3253
3254/*
3255 * This function is called by ext4_ext_map_blocks() from
3256 * ext4_get_blocks_dio_write() when DIO to write
3257 * to an uninitialized extent.
3258 *
3259 * Writing to an uninitialized extent may result in splitting the uninitialized
3260 * extent into multiple /initialized uninitialized extents (up to three)
3261 * There are three possibilities:
3262 * a> There is no split required: Entire extent should be uninitialized
3263 * b> Splits in two extents: Write is happening at either end of the extent
3264 * c> Splits in three extents: Somone is writing in middle of the extent
3265 *
3266 * One of more index blocks maybe needed if the extent tree grow after
3267 * the uninitialized extent split. To prevent ENOSPC occur at the IO
3268 * complete, we need to split the uninitialized extent before DIO submit
3269 * the IO. The uninitialized extent called at this time will be split
3270 * into three uninitialized extent(at most). After IO complete, the part
3271 * being filled will be convert to initialized by the end_io callback function
3272 * via ext4_convert_unwritten_extents().
3273 *
3274 * Returns the size of uninitialized extent to be written on success.
3275 */
3276static int ext4_split_unwritten_extents(handle_t *handle,
3277 struct inode *inode,
3278 struct ext4_map_blocks *map,
3279 struct ext4_ext_path *path,
3280 int flags)
3281{
3282 ext4_lblk_t eof_block;
3283 ext4_lblk_t ee_block;
3284 struct ext4_extent *ex;
3285 unsigned int ee_len;
3286 int split_flag = 0, depth;
3287
3288 ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3289 "block %llu, max_blocks %u\n", inode->i_ino,
3290 (unsigned long long)map->m_lblk, map->m_len);
3291
3292 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3293 inode->i_sb->s_blocksize_bits;
3294 if (eof_block < map->m_lblk + map->m_len)
3295 eof_block = map->m_lblk + map->m_len;
3296 /*
3297 * It is safe to convert extent to initialized via explicit
3298 * zeroout only if extent is fully insde i_size or new_size.
3299 */
3300 depth = ext_depth(inode);
3301 ex = path[depth].p_ext;
3302 ee_block = le32_to_cpu(ex->ee_block);
3303 ee_len = ext4_ext_get_actual_len(ex);
3304
3305 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3306 split_flag |= EXT4_EXT_MARK_UNINIT2;
3307
3308 flags |= EXT4_GET_BLOCKS_PRE_IO;
3309 return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3310}
3311
3312static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3313 struct inode *inode,
3314 struct ext4_ext_path *path)
3315{
3316 struct ext4_extent *ex;
3317 int depth;
3318 int err = 0;
3319
3320 depth = ext_depth(inode);
3321 ex = path[depth].p_ext;
3322
3323 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3324 "block %llu, max_blocks %u\n", inode->i_ino,
3325 (unsigned long long)le32_to_cpu(ex->ee_block),
3326 ext4_ext_get_actual_len(ex));
3327
3328 err = ext4_ext_get_access(handle, inode, path + depth);
3329 if (err)
3330 goto out;
3331 /* first mark the extent as initialized */
3332 ext4_ext_mark_initialized(ex);
3333
3334 /* note: ext4_ext_correct_indexes() isn't needed here because
3335 * borders are not changed
3336 */
3337 ext4_ext_try_to_merge(inode, path, ex);
3338
3339 /* Mark modified extent as dirty */
3340 err = ext4_ext_dirty(handle, inode, path + depth);
3341out:
3342 ext4_ext_show_leaf(inode, path);
3343 return err;
3344}
3345
3346static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3347 sector_t block, int count)
3348{
3349 int i;
3350 for (i = 0; i < count; i++)
3351 unmap_underlying_metadata(bdev, block + i);
3352}
3353
3354/*
3355 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3356 */
3357static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3358 ext4_lblk_t lblk,
3359 struct ext4_ext_path *path,
3360 unsigned int len)
3361{
3362 int i, depth;
3363 struct ext4_extent_header *eh;
3364 struct ext4_extent *last_ex;
3365
3366 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3367 return 0;
3368
3369 depth = ext_depth(inode);
3370 eh = path[depth].p_hdr;
3371
3372 /*
3373 * We're going to remove EOFBLOCKS_FL entirely in future so we
3374 * do not care for this case anymore. Simply remove the flag
3375 * if there are no extents.
3376 */
3377 if (unlikely(!eh->eh_entries))
3378 goto out;
3379 last_ex = EXT_LAST_EXTENT(eh);
3380 /*
3381 * We should clear the EOFBLOCKS_FL flag if we are writing the
3382 * last block in the last extent in the file. We test this by
3383 * first checking to see if the caller to
3384 * ext4_ext_get_blocks() was interested in the last block (or
3385 * a block beyond the last block) in the current extent. If
3386 * this turns out to be false, we can bail out from this
3387 * function immediately.
3388 */
3389 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3390 ext4_ext_get_actual_len(last_ex))
3391 return 0;
3392 /*
3393 * If the caller does appear to be planning to write at or
3394 * beyond the end of the current extent, we then test to see
3395 * if the current extent is the last extent in the file, by
3396 * checking to make sure it was reached via the rightmost node
3397 * at each level of the tree.
3398 */
3399 for (i = depth-1; i >= 0; i--)
3400 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3401 return 0;
3402out:
3403 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3404 return ext4_mark_inode_dirty(handle, inode);
3405}
3406
3407/**
3408 * ext4_find_delalloc_range: find delayed allocated block in the given range.
3409 *
3410 * Goes through the buffer heads in the range [lblk_start, lblk_end] and returns
3411 * whether there are any buffers marked for delayed allocation. It returns '1'
3412 * on the first delalloc'ed buffer head found. If no buffer head in the given
3413 * range is marked for delalloc, it returns 0.
3414 * lblk_start should always be <= lblk_end.
3415 * search_hint_reverse is to indicate that searching in reverse from lblk_end to
3416 * lblk_start might be more efficient (i.e., we will likely hit the delalloc'ed
3417 * block sooner). This is useful when blocks are truncated sequentially from
3418 * lblk_start towards lblk_end.
3419 */
3420static int ext4_find_delalloc_range(struct inode *inode,
3421 ext4_lblk_t lblk_start,
3422 ext4_lblk_t lblk_end,
3423 int search_hint_reverse)
3424{
3425 struct address_space *mapping = inode->i_mapping;
3426 struct buffer_head *head, *bh = NULL;
3427 struct page *page;
3428 ext4_lblk_t i, pg_lblk;
3429 pgoff_t index;
3430
3431 if (!test_opt(inode->i_sb, DELALLOC))
3432 return 0;
3433
3434 /* reverse search wont work if fs block size is less than page size */
3435 if (inode->i_blkbits < PAGE_CACHE_SHIFT)
3436 search_hint_reverse = 0;
3437
3438 if (search_hint_reverse)
3439 i = lblk_end;
3440 else
3441 i = lblk_start;
3442
3443 index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
3444
3445 while ((i >= lblk_start) && (i <= lblk_end)) {
3446 page = find_get_page(mapping, index);
3447 if (!page)
3448 goto nextpage;
3449
3450 if (!page_has_buffers(page))
3451 goto nextpage;
3452
3453 head = page_buffers(page);
3454 if (!head)
3455 goto nextpage;
3456
3457 bh = head;
3458 pg_lblk = index << (PAGE_CACHE_SHIFT -
3459 inode->i_blkbits);
3460 do {
3461 if (unlikely(pg_lblk < lblk_start)) {
3462 /*
3463 * This is possible when fs block size is less
3464 * than page size and our cluster starts/ends in
3465 * middle of the page. So we need to skip the
3466 * initial few blocks till we reach the 'lblk'
3467 */
3468 pg_lblk++;
3469 continue;
3470 }
3471
3472 /* Check if the buffer is delayed allocated and that it
3473 * is not yet mapped. (when da-buffers are mapped during
3474 * their writeout, their da_mapped bit is set.)
3475 */
3476 if (buffer_delay(bh) && !buffer_da_mapped(bh)) {
3477 page_cache_release(page);
3478 trace_ext4_find_delalloc_range(inode,
3479 lblk_start, lblk_end,
3480 search_hint_reverse,
3481 1, i);
3482 return 1;
3483 }
3484 if (search_hint_reverse)
3485 i--;
3486 else
3487 i++;
3488 } while ((i >= lblk_start) && (i <= lblk_end) &&
3489 ((bh = bh->b_this_page) != head));
3490nextpage:
3491 if (page)
3492 page_cache_release(page);
3493 /*
3494 * Move to next page. 'i' will be the first lblk in the next
3495 * page.
3496 */
3497 if (search_hint_reverse)
3498 index--;
3499 else
3500 index++;
3501 i = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
3502 }
3503
3504 trace_ext4_find_delalloc_range(inode, lblk_start, lblk_end,
3505 search_hint_reverse, 0, 0);
3506 return 0;
3507}
3508
3509int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk,
3510 int search_hint_reverse)
3511{
3512 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3513 ext4_lblk_t lblk_start, lblk_end;
3514 lblk_start = lblk & (~(sbi->s_cluster_ratio - 1));
3515 lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3516
3517 return ext4_find_delalloc_range(inode, lblk_start, lblk_end,
3518 search_hint_reverse);
3519}
3520
3521/**
3522 * Determines how many complete clusters (out of those specified by the 'map')
3523 * are under delalloc and were reserved quota for.
3524 * This function is called when we are writing out the blocks that were
3525 * originally written with their allocation delayed, but then the space was
3526 * allocated using fallocate() before the delayed allocation could be resolved.
3527 * The cases to look for are:
3528 * ('=' indicated delayed allocated blocks
3529 * '-' indicates non-delayed allocated blocks)
3530 * (a) partial clusters towards beginning and/or end outside of allocated range
3531 * are not delalloc'ed.
3532 * Ex:
3533 * |----c---=|====c====|====c====|===-c----|
3534 * |++++++ allocated ++++++|
3535 * ==> 4 complete clusters in above example
3536 *
3537 * (b) partial cluster (outside of allocated range) towards either end is
3538 * marked for delayed allocation. In this case, we will exclude that
3539 * cluster.
3540 * Ex:
3541 * |----====c========|========c========|
3542 * |++++++ allocated ++++++|
3543 * ==> 1 complete clusters in above example
3544 *
3545 * Ex:
3546 * |================c================|
3547 * |++++++ allocated ++++++|
3548 * ==> 0 complete clusters in above example
3549 *
3550 * The ext4_da_update_reserve_space will be called only if we
3551 * determine here that there were some "entire" clusters that span
3552 * this 'allocated' range.
3553 * In the non-bigalloc case, this function will just end up returning num_blks
3554 * without ever calling ext4_find_delalloc_range.
3555 */
3556static unsigned int
3557get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3558 unsigned int num_blks)
3559{
3560 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3561 ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3562 ext4_lblk_t lblk_from, lblk_to, c_offset;
3563 unsigned int allocated_clusters = 0;
3564
3565 alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3566 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3567
3568 /* max possible clusters for this allocation */
3569 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3570
3571 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3572
3573 /* Check towards left side */
3574 c_offset = lblk_start & (sbi->s_cluster_ratio - 1);
3575 if (c_offset) {
3576 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1));
3577 lblk_to = lblk_from + c_offset - 1;
3578
3579 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0))
3580 allocated_clusters--;
3581 }
3582
3583 /* Now check towards right. */
3584 c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1);
3585 if (allocated_clusters && c_offset) {
3586 lblk_from = lblk_start + num_blks;
3587 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3588
3589 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to, 0))
3590 allocated_clusters--;
3591 }
3592
3593 return allocated_clusters;
3594}
3595
3596static int
3597ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3598 struct ext4_map_blocks *map,
3599 struct ext4_ext_path *path, int flags,
3600 unsigned int allocated, ext4_fsblk_t newblock)
3601{
3602 int ret = 0;
3603 int err = 0;
3604 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3605
3606 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical "
3607 "block %llu, max_blocks %u, flags %x, allocated %u\n",
3608 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3609 flags, allocated);
3610 ext4_ext_show_leaf(inode, path);
3611
3612 trace_ext4_ext_handle_uninitialized_extents(inode, map, allocated,
3613 newblock);
3614
3615 /* get_block() before submit the IO, split the extent */
3616 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3617 ret = ext4_split_unwritten_extents(handle, inode, map,
3618 path, flags);
3619 /*
3620 * Flag the inode(non aio case) or end_io struct (aio case)
3621 * that this IO needs to conversion to written when IO is
3622 * completed
3623 */
3624 if (io)
3625 ext4_set_io_unwritten_flag(inode, io);
3626 else
3627 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3628 if (ext4_should_dioread_nolock(inode))
3629 map->m_flags |= EXT4_MAP_UNINIT;
3630 goto out;
3631 }
3632 /* IO end_io complete, convert the filled extent to written */
3633 if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3634 ret = ext4_convert_unwritten_extents_endio(handle, inode,
3635 path);
3636 if (ret >= 0) {
3637 ext4_update_inode_fsync_trans(handle, inode, 1);
3638 err = check_eofblocks_fl(handle, inode, map->m_lblk,
3639 path, map->m_len);
3640 } else
3641 err = ret;
3642 goto out2;
3643 }
3644 /* buffered IO case */
3645 /*
3646 * repeat fallocate creation request
3647 * we already have an unwritten extent
3648 */
3649 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
3650 goto map_out;
3651
3652 /* buffered READ or buffered write_begin() lookup */
3653 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3654 /*
3655 * We have blocks reserved already. We
3656 * return allocated blocks so that delalloc
3657 * won't do block reservation for us. But
3658 * the buffer head will be unmapped so that
3659 * a read from the block returns 0s.
3660 */
3661 map->m_flags |= EXT4_MAP_UNWRITTEN;
3662 goto out1;
3663 }
3664
3665 /* buffered write, writepage time, convert*/
3666 ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
3667 if (ret >= 0)
3668 ext4_update_inode_fsync_trans(handle, inode, 1);
3669out:
3670 if (ret <= 0) {
3671 err = ret;
3672 goto out2;
3673 } else
3674 allocated = ret;
3675 map->m_flags |= EXT4_MAP_NEW;
3676 /*
3677 * if we allocated more blocks than requested
3678 * we need to make sure we unmap the extra block
3679 * allocated. The actual needed block will get
3680 * unmapped later when we find the buffer_head marked
3681 * new.
3682 */
3683 if (allocated > map->m_len) {
3684 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3685 newblock + map->m_len,
3686 allocated - map->m_len);
3687 allocated = map->m_len;
3688 }
3689
3690 /*
3691 * If we have done fallocate with the offset that is already
3692 * delayed allocated, we would have block reservation
3693 * and quota reservation done in the delayed write path.
3694 * But fallocate would have already updated quota and block
3695 * count for this offset. So cancel these reservation
3696 */
3697 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
3698 unsigned int reserved_clusters;
3699 reserved_clusters = get_reserved_cluster_alloc(inode,
3700 map->m_lblk, map->m_len);
3701 if (reserved_clusters)
3702 ext4_da_update_reserve_space(inode,
3703 reserved_clusters,
3704 0);
3705 }
3706
3707map_out:
3708 map->m_flags |= EXT4_MAP_MAPPED;
3709 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
3710 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3711 map->m_len);
3712 if (err < 0)
3713 goto out2;
3714 }
3715out1:
3716 if (allocated > map->m_len)
3717 allocated = map->m_len;
3718 ext4_ext_show_leaf(inode, path);
3719 map->m_pblk = newblock;
3720 map->m_len = allocated;
3721out2:
3722 if (path) {
3723 ext4_ext_drop_refs(path);
3724 kfree(path);
3725 }
3726 return err ? err : allocated;
3727}
3728
3729/*
3730 * get_implied_cluster_alloc - check to see if the requested
3731 * allocation (in the map structure) overlaps with a cluster already
3732 * allocated in an extent.
3733 * @sb The filesystem superblock structure
3734 * @map The requested lblk->pblk mapping
3735 * @ex The extent structure which might contain an implied
3736 * cluster allocation
3737 *
3738 * This function is called by ext4_ext_map_blocks() after we failed to
3739 * find blocks that were already in the inode's extent tree. Hence,
3740 * we know that the beginning of the requested region cannot overlap
3741 * the extent from the inode's extent tree. There are three cases we
3742 * want to catch. The first is this case:
3743 *
3744 * |--- cluster # N--|
3745 * |--- extent ---| |---- requested region ---|
3746 * |==========|
3747 *
3748 * The second case that we need to test for is this one:
3749 *
3750 * |--------- cluster # N ----------------|
3751 * |--- requested region --| |------- extent ----|
3752 * |=======================|
3753 *
3754 * The third case is when the requested region lies between two extents
3755 * within the same cluster:
3756 * |------------- cluster # N-------------|
3757 * |----- ex -----| |---- ex_right ----|
3758 * |------ requested region ------|
3759 * |================|
3760 *
3761 * In each of the above cases, we need to set the map->m_pblk and
3762 * map->m_len so it corresponds to the return the extent labelled as
3763 * "|====|" from cluster #N, since it is already in use for data in
3764 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to
3765 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
3766 * as a new "allocated" block region. Otherwise, we will return 0 and
3767 * ext4_ext_map_blocks() will then allocate one or more new clusters
3768 * by calling ext4_mb_new_blocks().
3769 */
3770static int get_implied_cluster_alloc(struct super_block *sb,
3771 struct ext4_map_blocks *map,
3772 struct ext4_extent *ex,
3773 struct ext4_ext_path *path)
3774{
3775 struct ext4_sb_info *sbi = EXT4_SB(sb);
3776 ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
3777 ext4_lblk_t ex_cluster_start, ex_cluster_end;
3778 ext4_lblk_t rr_cluster_start;
3779 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3780 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3781 unsigned short ee_len = ext4_ext_get_actual_len(ex);
3782
3783 /* The extent passed in that we are trying to match */
3784 ex_cluster_start = EXT4_B2C(sbi, ee_block);
3785 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
3786
3787 /* The requested region passed into ext4_map_blocks() */
3788 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
3789
3790 if ((rr_cluster_start == ex_cluster_end) ||
3791 (rr_cluster_start == ex_cluster_start)) {
3792 if (rr_cluster_start == ex_cluster_end)
3793 ee_start += ee_len - 1;
3794 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) +
3795 c_offset;
3796 map->m_len = min(map->m_len,
3797 (unsigned) sbi->s_cluster_ratio - c_offset);
3798 /*
3799 * Check for and handle this case:
3800 *
3801 * |--------- cluster # N-------------|
3802 * |------- extent ----|
3803 * |--- requested region ---|
3804 * |===========|
3805 */
3806
3807 if (map->m_lblk < ee_block)
3808 map->m_len = min(map->m_len, ee_block - map->m_lblk);
3809
3810 /*
3811 * Check for the case where there is already another allocated
3812 * block to the right of 'ex' but before the end of the cluster.
3813 *
3814 * |------------- cluster # N-------------|
3815 * |----- ex -----| |---- ex_right ----|
3816 * |------ requested region ------|
3817 * |================|
3818 */
3819 if (map->m_lblk > ee_block) {
3820 ext4_lblk_t next = ext4_ext_next_allocated_block(path);
3821 map->m_len = min(map->m_len, next - map->m_lblk);
3822 }
3823
3824 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
3825 return 1;
3826 }
3827
3828 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
3829 return 0;
3830}
3831
3832
3833/*
3834 * Block allocation/map/preallocation routine for extents based files
3835 *
3836 *
3837 * Need to be called with
3838 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3839 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3840 *
3841 * return > 0, number of of blocks already mapped/allocated
3842 * if create == 0 and these are pre-allocated blocks
3843 * buffer head is unmapped
3844 * otherwise blocks are mapped
3845 *
3846 * return = 0, if plain look up failed (blocks have not been allocated)
3847 * buffer head is unmapped
3848 *
3849 * return < 0, error case.
3850 */
3851int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
3852 struct ext4_map_blocks *map, int flags)
3853{
3854 struct ext4_ext_path *path = NULL;
3855 struct ext4_extent newex, *ex, *ex2;
3856 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3857 ext4_fsblk_t newblock = 0;
3858 int free_on_err = 0, err = 0, depth, ret;
3859 unsigned int allocated = 0, offset = 0;
3860 unsigned int allocated_clusters = 0;
3861 struct ext4_allocation_request ar;
3862 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3863 ext4_lblk_t cluster_offset;
3864
3865 ext_debug("blocks %u/%u requested for inode %lu\n",
3866 map->m_lblk, map->m_len, inode->i_ino);
3867 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
3868
3869 /* check in cache */
3870 if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
3871 if (!newex.ee_start_lo && !newex.ee_start_hi) {
3872 if ((sbi->s_cluster_ratio > 1) &&
3873 ext4_find_delalloc_cluster(inode, map->m_lblk, 0))
3874 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3875
3876 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3877 /*
3878 * block isn't allocated yet and
3879 * user doesn't want to allocate it
3880 */
3881 goto out2;
3882 }
3883 /* we should allocate requested block */
3884 } else {
3885 /* block is already allocated */
3886 if (sbi->s_cluster_ratio > 1)
3887 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3888 newblock = map->m_lblk
3889 - le32_to_cpu(newex.ee_block)
3890 + ext4_ext_pblock(&newex);
3891 /* number of remaining blocks in the extent */
3892 allocated = ext4_ext_get_actual_len(&newex) -
3893 (map->m_lblk - le32_to_cpu(newex.ee_block));
3894 goto out;
3895 }
3896 }
3897
3898 /* find extent for this block */
3899 path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
3900 if (IS_ERR(path)) {
3901 err = PTR_ERR(path);
3902 path = NULL;
3903 goto out2;
3904 }
3905
3906 depth = ext_depth(inode);
3907
3908 /*
3909 * consistent leaf must not be empty;
3910 * this situation is possible, though, _during_ tree modification;
3911 * this is why assert can't be put in ext4_ext_find_extent()
3912 */
3913 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
3914 EXT4_ERROR_INODE(inode, "bad extent address "
3915 "lblock: %lu, depth: %d pblock %lld",
3916 (unsigned long) map->m_lblk, depth,
3917 path[depth].p_block);
3918 err = -EIO;
3919 goto out2;
3920 }
3921
3922 ex = path[depth].p_ext;
3923 if (ex) {
3924 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3925 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3926 unsigned short ee_len;
3927
3928 /*
3929 * Uninitialized extents are treated as holes, except that
3930 * we split out initialized portions during a write.
3931 */
3932 ee_len = ext4_ext_get_actual_len(ex);
3933
3934 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
3935
3936 /* if found extent covers block, simply return it */
3937 if (in_range(map->m_lblk, ee_block, ee_len)) {
3938 newblock = map->m_lblk - ee_block + ee_start;
3939 /* number of remaining blocks in the extent */
3940 allocated = ee_len - (map->m_lblk - ee_block);
3941 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
3942 ee_block, ee_len, newblock);
3943
3944 /*
3945 * Do not put uninitialized extent
3946 * in the cache
3947 */
3948 if (!ext4_ext_is_uninitialized(ex)) {
3949 ext4_ext_put_in_cache(inode, ee_block,
3950 ee_len, ee_start);
3951 goto out;
3952 }
3953 ret = ext4_ext_handle_uninitialized_extents(
3954 handle, inode, map, path, flags,
3955 allocated, newblock);
3956 return ret;
3957 }
3958 }
3959
3960 if ((sbi->s_cluster_ratio > 1) &&
3961 ext4_find_delalloc_cluster(inode, map->m_lblk, 0))
3962 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3963
3964 /*
3965 * requested block isn't allocated yet;
3966 * we couldn't try to create block if create flag is zero
3967 */
3968 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3969 /*
3970 * put just found gap into cache to speed up
3971 * subsequent requests
3972 */
3973 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
3974 goto out2;
3975 }
3976
3977 /*
3978 * Okay, we need to do block allocation.
3979 */
3980 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
3981 newex.ee_block = cpu_to_le32(map->m_lblk);
3982 cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
3983
3984 /*
3985 * If we are doing bigalloc, check to see if the extent returned
3986 * by ext4_ext_find_extent() implies a cluster we can use.
3987 */
3988 if (cluster_offset && ex &&
3989 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
3990 ar.len = allocated = map->m_len;
3991 newblock = map->m_pblk;
3992 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
3993 goto got_allocated_blocks;
3994 }
3995
3996 /* find neighbour allocated blocks */
3997 ar.lleft = map->m_lblk;
3998 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3999 if (err)
4000 goto out2;
4001 ar.lright = map->m_lblk;
4002 ex2 = NULL;
4003 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4004 if (err)
4005 goto out2;
4006
4007 /* Check if the extent after searching to the right implies a
4008 * cluster we can use. */
4009 if ((sbi->s_cluster_ratio > 1) && ex2 &&
4010 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4011 ar.len = allocated = map->m_len;
4012 newblock = map->m_pblk;
4013 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4014 goto got_allocated_blocks;
4015 }
4016
4017 /*
4018 * See if request is beyond maximum number of blocks we can have in
4019 * a single extent. For an initialized extent this limit is
4020 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
4021 * EXT_UNINIT_MAX_LEN.
4022 */
4023 if (map->m_len > EXT_INIT_MAX_LEN &&
4024 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
4025 map->m_len = EXT_INIT_MAX_LEN;
4026 else if (map->m_len > EXT_UNINIT_MAX_LEN &&
4027 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
4028 map->m_len = EXT_UNINIT_MAX_LEN;
4029
4030 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4031 newex.ee_len = cpu_to_le16(map->m_len);
4032 err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4033 if (err)
4034 allocated = ext4_ext_get_actual_len(&newex);
4035 else
4036 allocated = map->m_len;
4037
4038 /* allocate new block */
4039 ar.inode = inode;
4040 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4041 ar.logical = map->m_lblk;
4042 /*
4043 * We calculate the offset from the beginning of the cluster
4044 * for the logical block number, since when we allocate a
4045 * physical cluster, the physical block should start at the
4046 * same offset from the beginning of the cluster. This is
4047 * needed so that future calls to get_implied_cluster_alloc()
4048 * work correctly.
4049 */
4050 offset = map->m_lblk & (sbi->s_cluster_ratio - 1);
4051 ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4052 ar.goal -= offset;
4053 ar.logical -= offset;
4054 if (S_ISREG(inode->i_mode))
4055 ar.flags = EXT4_MB_HINT_DATA;
4056 else
4057 /* disable in-core preallocation for non-regular files */
4058 ar.flags = 0;
4059 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4060 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4061 newblock = ext4_mb_new_blocks(handle, &ar, &err);
4062 if (!newblock)
4063 goto out2;
4064 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4065 ar.goal, newblock, allocated);
4066 free_on_err = 1;
4067 allocated_clusters = ar.len;
4068 ar.len = EXT4_C2B(sbi, ar.len) - offset;
4069 if (ar.len > allocated)
4070 ar.len = allocated;
4071
4072got_allocated_blocks:
4073 /* try to insert new extent into found leaf and return */
4074 ext4_ext_store_pblock(&newex, newblock + offset);
4075 newex.ee_len = cpu_to_le16(ar.len);
4076 /* Mark uninitialized */
4077 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
4078 ext4_ext_mark_uninitialized(&newex);
4079 /*
4080 * io_end structure was created for every IO write to an
4081 * uninitialized extent. To avoid unnecessary conversion,
4082 * here we flag the IO that really needs the conversion.
4083 * For non asycn direct IO case, flag the inode state
4084 * that we need to perform conversion when IO is done.
4085 */
4086 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
4087 if (io)
4088 ext4_set_io_unwritten_flag(inode, io);
4089 else
4090 ext4_set_inode_state(inode,
4091 EXT4_STATE_DIO_UNWRITTEN);
4092 }
4093 if (ext4_should_dioread_nolock(inode))
4094 map->m_flags |= EXT4_MAP_UNINIT;
4095 }
4096
4097 err = 0;
4098 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4099 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4100 path, ar.len);
4101 if (!err)
4102 err = ext4_ext_insert_extent(handle, inode, path,
4103 &newex, flags);
4104 if (err && free_on_err) {
4105 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4106 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4107 /* free data blocks we just allocated */
4108 /* not a good idea to call discard here directly,
4109 * but otherwise we'd need to call it every free() */
4110 ext4_discard_preallocations(inode);
4111 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
4112 ext4_ext_get_actual_len(&newex), fb_flags);
4113 goto out2;
4114 }
4115
4116 /* previous routine could use block we allocated */
4117 newblock = ext4_ext_pblock(&newex);
4118 allocated = ext4_ext_get_actual_len(&newex);
4119 if (allocated > map->m_len)
4120 allocated = map->m_len;
4121 map->m_flags |= EXT4_MAP_NEW;
4122
4123 /*
4124 * Update reserved blocks/metadata blocks after successful
4125 * block allocation which had been deferred till now.
4126 */
4127 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4128 unsigned int reserved_clusters;
4129 /*
4130 * Check how many clusters we had reserved this allocated range
4131 */
4132 reserved_clusters = get_reserved_cluster_alloc(inode,
4133 map->m_lblk, allocated);
4134 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4135 if (reserved_clusters) {
4136 /*
4137 * We have clusters reserved for this range.
4138 * But since we are not doing actual allocation
4139 * and are simply using blocks from previously
4140 * allocated cluster, we should release the
4141 * reservation and not claim quota.
4142 */
4143 ext4_da_update_reserve_space(inode,
4144 reserved_clusters, 0);
4145 }
4146 } else {
4147 BUG_ON(allocated_clusters < reserved_clusters);
4148 /* We will claim quota for all newly allocated blocks.*/
4149 ext4_da_update_reserve_space(inode, allocated_clusters,
4150 1);
4151 if (reserved_clusters < allocated_clusters) {
4152 struct ext4_inode_info *ei = EXT4_I(inode);
4153 int reservation = allocated_clusters -
4154 reserved_clusters;
4155 /*
4156 * It seems we claimed few clusters outside of
4157 * the range of this allocation. We should give
4158 * it back to the reservation pool. This can
4159 * happen in the following case:
4160 *
4161 * * Suppose s_cluster_ratio is 4 (i.e., each
4162 * cluster has 4 blocks. Thus, the clusters
4163 * are [0-3],[4-7],[8-11]...
4164 * * First comes delayed allocation write for
4165 * logical blocks 10 & 11. Since there were no
4166 * previous delayed allocated blocks in the
4167 * range [8-11], we would reserve 1 cluster
4168 * for this write.
4169 * * Next comes write for logical blocks 3 to 8.
4170 * In this case, we will reserve 2 clusters
4171 * (for [0-3] and [4-7]; and not for [8-11] as
4172 * that range has a delayed allocated blocks.
4173 * Thus total reserved clusters now becomes 3.
4174 * * Now, during the delayed allocation writeout
4175 * time, we will first write blocks [3-8] and
4176 * allocate 3 clusters for writing these
4177 * blocks. Also, we would claim all these
4178 * three clusters above.
4179 * * Now when we come here to writeout the
4180 * blocks [10-11], we would expect to claim
4181 * the reservation of 1 cluster we had made
4182 * (and we would claim it since there are no
4183 * more delayed allocated blocks in the range
4184 * [8-11]. But our reserved cluster count had
4185 * already gone to 0.
4186 *
4187 * Thus, at the step 4 above when we determine
4188 * that there are still some unwritten delayed
4189 * allocated blocks outside of our current
4190 * block range, we should increment the
4191 * reserved clusters count so that when the
4192 * remaining blocks finally gets written, we
4193 * could claim them.
4194 */
4195 dquot_reserve_block(inode,
4196 EXT4_C2B(sbi, reservation));
4197 spin_lock(&ei->i_block_reservation_lock);
4198 ei->i_reserved_data_blocks += reservation;
4199 spin_unlock(&ei->i_block_reservation_lock);
4200 }
4201 }
4202 }
4203
4204 /*
4205 * Cache the extent and update transaction to commit on fdatasync only
4206 * when it is _not_ an uninitialized extent.
4207 */
4208 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
4209 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
4210 ext4_update_inode_fsync_trans(handle, inode, 1);
4211 } else
4212 ext4_update_inode_fsync_trans(handle, inode, 0);
4213out:
4214 if (allocated > map->m_len)
4215 allocated = map->m_len;
4216 ext4_ext_show_leaf(inode, path);
4217 map->m_flags |= EXT4_MAP_MAPPED;
4218 map->m_pblk = newblock;
4219 map->m_len = allocated;
4220out2:
4221 if (path) {
4222 ext4_ext_drop_refs(path);
4223 kfree(path);
4224 }
4225
4226 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
4227 newblock, map->m_len, err ? err : allocated);
4228
4229 return err ? err : allocated;
4230}
4231
4232void ext4_ext_truncate(struct inode *inode)
4233{
4234 struct address_space *mapping = inode->i_mapping;
4235 struct super_block *sb = inode->i_sb;
4236 ext4_lblk_t last_block;
4237 handle_t *handle;
4238 loff_t page_len;
4239 int err = 0;
4240
4241 /*
4242 * finish any pending end_io work so we won't run the risk of
4243 * converting any truncated blocks to initialized later
4244 */
4245 ext4_flush_completed_IO(inode);
4246
4247 /*
4248 * probably first extent we're gonna free will be last in block
4249 */
4250 err = ext4_writepage_trans_blocks(inode);
4251 handle = ext4_journal_start(inode, err);
4252 if (IS_ERR(handle))
4253 return;
4254
4255 if (inode->i_size % PAGE_CACHE_SIZE != 0) {
4256 page_len = PAGE_CACHE_SIZE -
4257 (inode->i_size & (PAGE_CACHE_SIZE - 1));
4258
4259 err = ext4_discard_partial_page_buffers(handle,
4260 mapping, inode->i_size, page_len, 0);
4261
4262 if (err)
4263 goto out_stop;
4264 }
4265
4266 if (ext4_orphan_add(handle, inode))
4267 goto out_stop;
4268
4269 down_write(&EXT4_I(inode)->i_data_sem);
4270 ext4_ext_invalidate_cache(inode);
4271
4272 ext4_discard_preallocations(inode);
4273
4274 /*
4275 * TODO: optimization is possible here.
4276 * Probably we need not scan at all,
4277 * because page truncation is enough.
4278 */
4279
4280 /* we have to know where to truncate from in crash case */
4281 EXT4_I(inode)->i_disksize = inode->i_size;
4282 ext4_mark_inode_dirty(handle, inode);
4283
4284 last_block = (inode->i_size + sb->s_blocksize - 1)
4285 >> EXT4_BLOCK_SIZE_BITS(sb);
4286 err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4287
4288 /* In a multi-transaction truncate, we only make the final
4289 * transaction synchronous.
4290 */
4291 if (IS_SYNC(inode))
4292 ext4_handle_sync(handle);
4293
4294 up_write(&EXT4_I(inode)->i_data_sem);
4295
4296out_stop:
4297 /*
4298 * If this was a simple ftruncate() and the file will remain alive,
4299 * then we need to clear up the orphan record which we created above.
4300 * However, if this was a real unlink then we were called by
4301 * ext4_delete_inode(), and we allow that function to clean up the
4302 * orphan info for us.
4303 */
4304 if (inode->i_nlink)
4305 ext4_orphan_del(handle, inode);
4306
4307 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4308 ext4_mark_inode_dirty(handle, inode);
4309 ext4_journal_stop(handle);
4310}
4311
4312static void ext4_falloc_update_inode(struct inode *inode,
4313 int mode, loff_t new_size, int update_ctime)
4314{
4315 struct timespec now;
4316
4317 if (update_ctime) {
4318 now = current_fs_time(inode->i_sb);
4319 if (!timespec_equal(&inode->i_ctime, &now))
4320 inode->i_ctime = now;
4321 }
4322 /*
4323 * Update only when preallocation was requested beyond
4324 * the file size.
4325 */
4326 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
4327 if (new_size > i_size_read(inode))
4328 i_size_write(inode, new_size);
4329 if (new_size > EXT4_I(inode)->i_disksize)
4330 ext4_update_i_disksize(inode, new_size);
4331 } else {
4332 /*
4333 * Mark that we allocate beyond EOF so the subsequent truncate
4334 * can proceed even if the new size is the same as i_size.
4335 */
4336 if (new_size > i_size_read(inode))
4337 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4338 }
4339
4340}
4341
4342/*
4343 * preallocate space for a file. This implements ext4's fallocate file
4344 * operation, which gets called from sys_fallocate system call.
4345 * For block-mapped files, posix_fallocate should fall back to the method
4346 * of writing zeroes to the required new blocks (the same behavior which is
4347 * expected for file systems which do not support fallocate() system call).
4348 */
4349long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4350{
4351 struct inode *inode = file->f_path.dentry->d_inode;
4352 handle_t *handle;
4353 loff_t new_size;
4354 unsigned int max_blocks;
4355 int ret = 0;
4356 int ret2 = 0;
4357 int retries = 0;
4358 int flags;
4359 struct ext4_map_blocks map;
4360 unsigned int credits, blkbits = inode->i_blkbits;
4361
4362 /*
4363 * currently supporting (pre)allocate mode for extent-based
4364 * files _only_
4365 */
4366 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4367 return -EOPNOTSUPP;
4368
4369 /* Return error if mode is not supported */
4370 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
4371 return -EOPNOTSUPP;
4372
4373 if (mode & FALLOC_FL_PUNCH_HOLE)
4374 return ext4_punch_hole(file, offset, len);
4375
4376 trace_ext4_fallocate_enter(inode, offset, len, mode);
4377 map.m_lblk = offset >> blkbits;
4378 /*
4379 * We can't just convert len to max_blocks because
4380 * If blocksize = 4096 offset = 3072 and len = 2048
4381 */
4382 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4383 - map.m_lblk;
4384 /*
4385 * credits to insert 1 extent into extent tree
4386 */
4387 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4388 mutex_lock(&inode->i_mutex);
4389 ret = inode_newsize_ok(inode, (len + offset));
4390 if (ret) {
4391 mutex_unlock(&inode->i_mutex);
4392 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4393 return ret;
4394 }
4395 flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT;
4396 if (mode & FALLOC_FL_KEEP_SIZE)
4397 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4398 /*
4399 * Don't normalize the request if it can fit in one extent so
4400 * that it doesn't get unnecessarily split into multiple
4401 * extents.
4402 */
4403 if (len <= EXT_UNINIT_MAX_LEN << blkbits)
4404 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4405retry:
4406 while (ret >= 0 && ret < max_blocks) {
4407 map.m_lblk = map.m_lblk + ret;
4408 map.m_len = max_blocks = max_blocks - ret;
4409 handle = ext4_journal_start(inode, credits);
4410 if (IS_ERR(handle)) {
4411 ret = PTR_ERR(handle);
4412 break;
4413 }
4414 ret = ext4_map_blocks(handle, inode, &map, flags);
4415 if (ret <= 0) {
4416#ifdef EXT4FS_DEBUG
4417 WARN_ON(ret <= 0);
4418 printk(KERN_ERR "%s: ext4_ext_map_blocks "
4419 "returned error inode#%lu, block=%u, "
4420 "max_blocks=%u", __func__,
4421 inode->i_ino, map.m_lblk, max_blocks);
4422#endif
4423 ext4_mark_inode_dirty(handle, inode);
4424 ret2 = ext4_journal_stop(handle);
4425 break;
4426 }
4427 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
4428 blkbits) >> blkbits))
4429 new_size = offset + len;
4430 else
4431 new_size = ((loff_t) map.m_lblk + ret) << blkbits;
4432
4433 ext4_falloc_update_inode(inode, mode, new_size,
4434 (map.m_flags & EXT4_MAP_NEW));
4435 ext4_mark_inode_dirty(handle, inode);
4436 ret2 = ext4_journal_stop(handle);
4437 if (ret2)
4438 break;
4439 }
4440 if (ret == -ENOSPC &&
4441 ext4_should_retry_alloc(inode->i_sb, &retries)) {
4442 ret = 0;
4443 goto retry;
4444 }
4445 mutex_unlock(&inode->i_mutex);
4446 trace_ext4_fallocate_exit(inode, offset, max_blocks,
4447 ret > 0 ? ret2 : ret);
4448 return ret > 0 ? ret2 : ret;
4449}
4450
4451/*
4452 * This function convert a range of blocks to written extents
4453 * The caller of this function will pass the start offset and the size.
4454 * all unwritten extents within this range will be converted to
4455 * written extents.
4456 *
4457 * This function is called from the direct IO end io call back
4458 * function, to convert the fallocated extents after IO is completed.
4459 * Returns 0 on success.
4460 */
4461int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
4462 ssize_t len)
4463{
4464 handle_t *handle;
4465 unsigned int max_blocks;
4466 int ret = 0;
4467 int ret2 = 0;
4468 struct ext4_map_blocks map;
4469 unsigned int credits, blkbits = inode->i_blkbits;
4470
4471 map.m_lblk = offset >> blkbits;
4472 /*
4473 * We can't just convert len to max_blocks because
4474 * If blocksize = 4096 offset = 3072 and len = 2048
4475 */
4476 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
4477 map.m_lblk);
4478 /*
4479 * credits to insert 1 extent into extent tree
4480 */
4481 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4482 while (ret >= 0 && ret < max_blocks) {
4483 map.m_lblk += ret;
4484 map.m_len = (max_blocks -= ret);
4485 handle = ext4_journal_start(inode, credits);
4486 if (IS_ERR(handle)) {
4487 ret = PTR_ERR(handle);
4488 break;
4489 }
4490 ret = ext4_map_blocks(handle, inode, &map,
4491 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4492 if (ret <= 0) {
4493 WARN_ON(ret <= 0);
4494 ext4_msg(inode->i_sb, KERN_ERR,
4495 "%s:%d: inode #%lu: block %u: len %u: "
4496 "ext4_ext_map_blocks returned %d",
4497 __func__, __LINE__, inode->i_ino, map.m_lblk,
4498 map.m_len, ret);
4499 }
4500 ext4_mark_inode_dirty(handle, inode);
4501 ret2 = ext4_journal_stop(handle);
4502 if (ret <= 0 || ret2 )
4503 break;
4504 }
4505 return ret > 0 ? ret2 : ret;
4506}
4507
4508/*
4509 * Callback function called for each extent to gather FIEMAP information.
4510 */
4511static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next,
4512 struct ext4_ext_cache *newex, struct ext4_extent *ex,
4513 void *data)
4514{
4515 __u64 logical;
4516 __u64 physical;
4517 __u64 length;
4518 __u32 flags = 0;
4519 int ret = 0;
4520 struct fiemap_extent_info *fieinfo = data;
4521 unsigned char blksize_bits;
4522
4523 blksize_bits = inode->i_sb->s_blocksize_bits;
4524 logical = (__u64)newex->ec_block << blksize_bits;
4525
4526 if (newex->ec_start == 0) {
4527 /*
4528 * No extent in extent-tree contains block @newex->ec_start,
4529 * then the block may stay in 1)a hole or 2)delayed-extent.
4530 *
4531 * Holes or delayed-extents are processed as follows.
4532 * 1. lookup dirty pages with specified range in pagecache.
4533 * If no page is got, then there is no delayed-extent and
4534 * return with EXT_CONTINUE.
4535 * 2. find the 1st mapped buffer,
4536 * 3. check if the mapped buffer is both in the request range
4537 * and a delayed buffer. If not, there is no delayed-extent,
4538 * then return.
4539 * 4. a delayed-extent is found, the extent will be collected.
4540 */
4541 ext4_lblk_t end = 0;
4542 pgoff_t last_offset;
4543 pgoff_t offset;
4544 pgoff_t index;
4545 pgoff_t start_index = 0;
4546 struct page **pages = NULL;
4547 struct buffer_head *bh = NULL;
4548 struct buffer_head *head = NULL;
4549 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
4550
4551 pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
4552 if (pages == NULL)
4553 return -ENOMEM;
4554
4555 offset = logical >> PAGE_SHIFT;
4556repeat:
4557 last_offset = offset;
4558 head = NULL;
4559 ret = find_get_pages_tag(inode->i_mapping, &offset,
4560 PAGECACHE_TAG_DIRTY, nr_pages, pages);
4561
4562 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
4563 /* First time, try to find a mapped buffer. */
4564 if (ret == 0) {
4565out:
4566 for (index = 0; index < ret; index++)
4567 page_cache_release(pages[index]);
4568 /* just a hole. */
4569 kfree(pages);
4570 return EXT_CONTINUE;
4571 }
4572 index = 0;
4573
4574next_page:
4575 /* Try to find the 1st mapped buffer. */
4576 end = ((__u64)pages[index]->index << PAGE_SHIFT) >>
4577 blksize_bits;
4578 if (!page_has_buffers(pages[index]))
4579 goto out;
4580 head = page_buffers(pages[index]);
4581 if (!head)
4582 goto out;
4583
4584 index++;
4585 bh = head;
4586 do {
4587 if (end >= newex->ec_block +
4588 newex->ec_len)
4589 /* The buffer is out of
4590 * the request range.
4591 */
4592 goto out;
4593
4594 if (buffer_mapped(bh) &&
4595 end >= newex->ec_block) {
4596 start_index = index - 1;
4597 /* get the 1st mapped buffer. */
4598 goto found_mapped_buffer;
4599 }
4600
4601 bh = bh->b_this_page;
4602 end++;
4603 } while (bh != head);
4604
4605 /* No mapped buffer in the range found in this page,
4606 * We need to look up next page.
4607 */
4608 if (index >= ret) {
4609 /* There is no page left, but we need to limit
4610 * newex->ec_len.
4611 */
4612 newex->ec_len = end - newex->ec_block;
4613 goto out;
4614 }
4615 goto next_page;
4616 } else {
4617 /*Find contiguous delayed buffers. */
4618 if (ret > 0 && pages[0]->index == last_offset)
4619 head = page_buffers(pages[0]);
4620 bh = head;
4621 index = 1;
4622 start_index = 0;
4623 }
4624
4625found_mapped_buffer:
4626 if (bh != NULL && buffer_delay(bh)) {
4627 /* 1st or contiguous delayed buffer found. */
4628 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
4629 /*
4630 * 1st delayed buffer found, record
4631 * the start of extent.
4632 */
4633 flags |= FIEMAP_EXTENT_DELALLOC;
4634 newex->ec_block = end;
4635 logical = (__u64)end << blksize_bits;
4636 }
4637 /* Find contiguous delayed buffers. */
4638 do {
4639 if (!buffer_delay(bh))
4640 goto found_delayed_extent;
4641 bh = bh->b_this_page;
4642 end++;
4643 } while (bh != head);
4644
4645 for (; index < ret; index++) {
4646 if (!page_has_buffers(pages[index])) {
4647 bh = NULL;
4648 break;
4649 }
4650 head = page_buffers(pages[index]);
4651 if (!head) {
4652 bh = NULL;
4653 break;
4654 }
4655
4656 if (pages[index]->index !=
4657 pages[start_index]->index + index
4658 - start_index) {
4659 /* Blocks are not contiguous. */
4660 bh = NULL;
4661 break;
4662 }
4663 bh = head;
4664 do {
4665 if (!buffer_delay(bh))
4666 /* Delayed-extent ends. */
4667 goto found_delayed_extent;
4668 bh = bh->b_this_page;
4669 end++;
4670 } while (bh != head);
4671 }
4672 } else if (!(flags & FIEMAP_EXTENT_DELALLOC))
4673 /* a hole found. */
4674 goto out;
4675
4676found_delayed_extent:
4677 newex->ec_len = min(end - newex->ec_block,
4678 (ext4_lblk_t)EXT_INIT_MAX_LEN);
4679 if (ret == nr_pages && bh != NULL &&
4680 newex->ec_len < EXT_INIT_MAX_LEN &&
4681 buffer_delay(bh)) {
4682 /* Have not collected an extent and continue. */
4683 for (index = 0; index < ret; index++)
4684 page_cache_release(pages[index]);
4685 goto repeat;
4686 }
4687
4688 for (index = 0; index < ret; index++)
4689 page_cache_release(pages[index]);
4690 kfree(pages);
4691 }
4692
4693 physical = (__u64)newex->ec_start << blksize_bits;
4694 length = (__u64)newex->ec_len << blksize_bits;
4695
4696 if (ex && ext4_ext_is_uninitialized(ex))
4697 flags |= FIEMAP_EXTENT_UNWRITTEN;
4698
4699 if (next == EXT_MAX_BLOCKS)
4700 flags |= FIEMAP_EXTENT_LAST;
4701
4702 ret = fiemap_fill_next_extent(fieinfo, logical, physical,
4703 length, flags);
4704 if (ret < 0)
4705 return ret;
4706 if (ret == 1)
4707 return EXT_BREAK;
4708 return EXT_CONTINUE;
4709}
4710/* fiemap flags we can handle specified here */
4711#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4712
4713static int ext4_xattr_fiemap(struct inode *inode,
4714 struct fiemap_extent_info *fieinfo)
4715{
4716 __u64 physical = 0;
4717 __u64 length;
4718 __u32 flags = FIEMAP_EXTENT_LAST;
4719 int blockbits = inode->i_sb->s_blocksize_bits;
4720 int error = 0;
4721
4722 /* in-inode? */
4723 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4724 struct ext4_iloc iloc;
4725 int offset; /* offset of xattr in inode */
4726
4727 error = ext4_get_inode_loc(inode, &iloc);
4728 if (error)
4729 return error;
4730 physical = iloc.bh->b_blocknr << blockbits;
4731 offset = EXT4_GOOD_OLD_INODE_SIZE +
4732 EXT4_I(inode)->i_extra_isize;
4733 physical += offset;
4734 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4735 flags |= FIEMAP_EXTENT_DATA_INLINE;
4736 brelse(iloc.bh);
4737 } else { /* external block */
4738 physical = EXT4_I(inode)->i_file_acl << blockbits;
4739 length = inode->i_sb->s_blocksize;
4740 }
4741
4742 if (physical)
4743 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4744 length, flags);
4745 return (error < 0 ? error : 0);
4746}
4747
4748/*
4749 * ext4_ext_punch_hole
4750 *
4751 * Punches a hole of "length" bytes in a file starting
4752 * at byte "offset"
4753 *
4754 * @inode: The inode of the file to punch a hole in
4755 * @offset: The starting byte offset of the hole
4756 * @length: The length of the hole
4757 *
4758 * Returns the number of blocks removed or negative on err
4759 */
4760int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
4761{
4762 struct inode *inode = file->f_path.dentry->d_inode;
4763 struct super_block *sb = inode->i_sb;
4764 ext4_lblk_t first_block, stop_block;
4765 struct address_space *mapping = inode->i_mapping;
4766 handle_t *handle;
4767 loff_t first_page, last_page, page_len;
4768 loff_t first_page_offset, last_page_offset;
4769 int credits, err = 0;
4770
4771 /* No need to punch hole beyond i_size */
4772 if (offset >= inode->i_size)
4773 return 0;
4774
4775 /*
4776 * If the hole extends beyond i_size, set the hole
4777 * to end after the page that contains i_size
4778 */
4779 if (offset + length > inode->i_size) {
4780 length = inode->i_size +
4781 PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) -
4782 offset;
4783 }
4784
4785 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
4786 last_page = (offset + length) >> PAGE_CACHE_SHIFT;
4787
4788 first_page_offset = first_page << PAGE_CACHE_SHIFT;
4789 last_page_offset = last_page << PAGE_CACHE_SHIFT;
4790
4791 /*
4792 * Write out all dirty pages to avoid race conditions
4793 * Then release them.
4794 */
4795 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4796 err = filemap_write_and_wait_range(mapping,
4797 offset, offset + length - 1);
4798
4799 if (err)
4800 return err;
4801 }
4802
4803 /* Now release the pages */
4804 if (last_page_offset > first_page_offset) {
4805 truncate_pagecache_range(inode, first_page_offset,
4806 last_page_offset - 1);
4807 }
4808
4809 /* finish any pending end_io work */
4810 ext4_flush_completed_IO(inode);
4811
4812 credits = ext4_writepage_trans_blocks(inode);
4813 handle = ext4_journal_start(inode, credits);
4814 if (IS_ERR(handle))
4815 return PTR_ERR(handle);
4816
4817 err = ext4_orphan_add(handle, inode);
4818 if (err)
4819 goto out;
4820
4821 /*
4822 * Now we need to zero out the non-page-aligned data in the
4823 * pages at the start and tail of the hole, and unmap the buffer
4824 * heads for the block aligned regions of the page that were
4825 * completely zeroed.
4826 */
4827 if (first_page > last_page) {
4828 /*
4829 * If the file space being truncated is contained within a page
4830 * just zero out and unmap the middle of that page
4831 */
4832 err = ext4_discard_partial_page_buffers(handle,
4833 mapping, offset, length, 0);
4834
4835 if (err)
4836 goto out;
4837 } else {
4838 /*
4839 * zero out and unmap the partial page that contains
4840 * the start of the hole
4841 */
4842 page_len = first_page_offset - offset;
4843 if (page_len > 0) {
4844 err = ext4_discard_partial_page_buffers(handle, mapping,
4845 offset, page_len, 0);
4846 if (err)
4847 goto out;
4848 }
4849
4850 /*
4851 * zero out and unmap the partial page that contains
4852 * the end of the hole
4853 */
4854 page_len = offset + length - last_page_offset;
4855 if (page_len > 0) {
4856 err = ext4_discard_partial_page_buffers(handle, mapping,
4857 last_page_offset, page_len, 0);
4858 if (err)
4859 goto out;
4860 }
4861 }
4862
4863 /*
4864 * If i_size is contained in the last page, we need to
4865 * unmap and zero the partial page after i_size
4866 */
4867 if (inode->i_size >> PAGE_CACHE_SHIFT == last_page &&
4868 inode->i_size % PAGE_CACHE_SIZE != 0) {
4869
4870 page_len = PAGE_CACHE_SIZE -
4871 (inode->i_size & (PAGE_CACHE_SIZE - 1));
4872
4873 if (page_len > 0) {
4874 err = ext4_discard_partial_page_buffers(handle,
4875 mapping, inode->i_size, page_len, 0);
4876
4877 if (err)
4878 goto out;
4879 }
4880 }
4881
4882 first_block = (offset + sb->s_blocksize - 1) >>
4883 EXT4_BLOCK_SIZE_BITS(sb);
4884 stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4885
4886 /* If there are no blocks to remove, return now */
4887 if (first_block >= stop_block)
4888 goto out;
4889
4890 down_write(&EXT4_I(inode)->i_data_sem);
4891 ext4_ext_invalidate_cache(inode);
4892 ext4_discard_preallocations(inode);
4893
4894 err = ext4_ext_remove_space(inode, first_block, stop_block - 1);
4895
4896 ext4_ext_invalidate_cache(inode);
4897 ext4_discard_preallocations(inode);
4898
4899 if (IS_SYNC(inode))
4900 ext4_handle_sync(handle);
4901
4902 up_write(&EXT4_I(inode)->i_data_sem);
4903
4904out:
4905 ext4_orphan_del(handle, inode);
4906 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4907 ext4_mark_inode_dirty(handle, inode);
4908 ext4_journal_stop(handle);
4909 return err;
4910}
4911int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4912 __u64 start, __u64 len)
4913{
4914 ext4_lblk_t start_blk;
4915 int error = 0;
4916
4917 /* fallback to generic here if not in extents fmt */
4918 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4919 return generic_block_fiemap(inode, fieinfo, start, len,
4920 ext4_get_block);
4921
4922 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4923 return -EBADR;
4924
4925 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4926 error = ext4_xattr_fiemap(inode, fieinfo);
4927 } else {
4928 ext4_lblk_t len_blks;
4929 __u64 last_blk;
4930
4931 start_blk = start >> inode->i_sb->s_blocksize_bits;
4932 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4933 if (last_blk >= EXT_MAX_BLOCKS)
4934 last_blk = EXT_MAX_BLOCKS-1;
4935 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4936
4937 /*
4938 * Walk the extent tree gathering extent information.
4939 * ext4_ext_fiemap_cb will push extents back to user.
4940 */
4941 error = ext4_ext_walk_space(inode, start_blk, len_blks,
4942 ext4_ext_fiemap_cb, fieinfo);
4943 }
4944
4945 return error;
4946}
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 License
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/fs.h>
33#include <linux/time.h>
34#include <linux/jbd2.h>
35#include <linux/highuid.h>
36#include <linux/pagemap.h>
37#include <linux/quotaops.h>
38#include <linux/string.h>
39#include <linux/slab.h>
40#include <asm/uaccess.h>
41#include <linux/fiemap.h>
42#include <linux/backing-dev.h>
43#include "ext4_jbd2.h"
44#include "ext4_extents.h"
45#include "xattr.h"
46
47#include <trace/events/ext4.h>
48
49/*
50 * used by extent splitting.
51 */
52#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
53 due to ENOSPC */
54#define EXT4_EXT_MARK_UNWRIT1 0x2 /* mark first half unwritten */
55#define EXT4_EXT_MARK_UNWRIT2 0x4 /* mark second half unwritten */
56
57#define EXT4_EXT_DATA_VALID1 0x8 /* first half contains valid data */
58#define EXT4_EXT_DATA_VALID2 0x10 /* second half contains valid data */
59
60static __le32 ext4_extent_block_csum(struct inode *inode,
61 struct ext4_extent_header *eh)
62{
63 struct ext4_inode_info *ei = EXT4_I(inode);
64 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
65 __u32 csum;
66
67 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
68 EXT4_EXTENT_TAIL_OFFSET(eh));
69 return cpu_to_le32(csum);
70}
71
72static int ext4_extent_block_csum_verify(struct inode *inode,
73 struct ext4_extent_header *eh)
74{
75 struct ext4_extent_tail *et;
76
77 if (!ext4_has_metadata_csum(inode->i_sb))
78 return 1;
79
80 et = find_ext4_extent_tail(eh);
81 if (et->et_checksum != ext4_extent_block_csum(inode, eh))
82 return 0;
83 return 1;
84}
85
86static void ext4_extent_block_csum_set(struct inode *inode,
87 struct ext4_extent_header *eh)
88{
89 struct ext4_extent_tail *et;
90
91 if (!ext4_has_metadata_csum(inode->i_sb))
92 return;
93
94 et = find_ext4_extent_tail(eh);
95 et->et_checksum = ext4_extent_block_csum(inode, eh);
96}
97
98static int ext4_split_extent(handle_t *handle,
99 struct inode *inode,
100 struct ext4_ext_path **ppath,
101 struct ext4_map_blocks *map,
102 int split_flag,
103 int flags);
104
105static int ext4_split_extent_at(handle_t *handle,
106 struct inode *inode,
107 struct ext4_ext_path **ppath,
108 ext4_lblk_t split,
109 int split_flag,
110 int flags);
111
112static int ext4_find_delayed_extent(struct inode *inode,
113 struct extent_status *newes);
114
115static int ext4_ext_truncate_extend_restart(handle_t *handle,
116 struct inode *inode,
117 int needed)
118{
119 int err;
120
121 if (!ext4_handle_valid(handle))
122 return 0;
123 if (handle->h_buffer_credits > needed)
124 return 0;
125 err = ext4_journal_extend(handle, needed);
126 if (err <= 0)
127 return err;
128 err = ext4_truncate_restart_trans(handle, inode, needed);
129 if (err == 0)
130 err = -EAGAIN;
131
132 return err;
133}
134
135/*
136 * could return:
137 * - EROFS
138 * - ENOMEM
139 */
140static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
141 struct ext4_ext_path *path)
142{
143 if (path->p_bh) {
144 /* path points to block */
145 BUFFER_TRACE(path->p_bh, "get_write_access");
146 return ext4_journal_get_write_access(handle, path->p_bh);
147 }
148 /* path points to leaf/index in inode body */
149 /* we use in-core data, no need to protect them */
150 return 0;
151}
152
153/*
154 * could return:
155 * - EROFS
156 * - ENOMEM
157 * - EIO
158 */
159int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
160 struct inode *inode, struct ext4_ext_path *path)
161{
162 int err;
163
164 WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
165 if (path->p_bh) {
166 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
167 /* path points to block */
168 err = __ext4_handle_dirty_metadata(where, line, handle,
169 inode, path->p_bh);
170 } else {
171 /* path points to leaf/index in inode body */
172 err = ext4_mark_inode_dirty(handle, inode);
173 }
174 return err;
175}
176
177static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
178 struct ext4_ext_path *path,
179 ext4_lblk_t block)
180{
181 if (path) {
182 int depth = path->p_depth;
183 struct ext4_extent *ex;
184
185 /*
186 * Try to predict block placement assuming that we are
187 * filling in a file which will eventually be
188 * non-sparse --- i.e., in the case of libbfd writing
189 * an ELF object sections out-of-order but in a way
190 * the eventually results in a contiguous object or
191 * executable file, or some database extending a table
192 * space file. However, this is actually somewhat
193 * non-ideal if we are writing a sparse file such as
194 * qemu or KVM writing a raw image file that is going
195 * to stay fairly sparse, since it will end up
196 * fragmenting the file system's free space. Maybe we
197 * should have some hueristics or some way to allow
198 * userspace to pass a hint to file system,
199 * especially if the latter case turns out to be
200 * common.
201 */
202 ex = path[depth].p_ext;
203 if (ex) {
204 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
205 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
206
207 if (block > ext_block)
208 return ext_pblk + (block - ext_block);
209 else
210 return ext_pblk - (ext_block - block);
211 }
212
213 /* it looks like index is empty;
214 * try to find starting block from index itself */
215 if (path[depth].p_bh)
216 return path[depth].p_bh->b_blocknr;
217 }
218
219 /* OK. use inode's group */
220 return ext4_inode_to_goal_block(inode);
221}
222
223/*
224 * Allocation for a meta data block
225 */
226static ext4_fsblk_t
227ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
228 struct ext4_ext_path *path,
229 struct ext4_extent *ex, int *err, unsigned int flags)
230{
231 ext4_fsblk_t goal, newblock;
232
233 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
234 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
235 NULL, err);
236 return newblock;
237}
238
239static inline int ext4_ext_space_block(struct inode *inode, int check)
240{
241 int size;
242
243 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
244 / sizeof(struct ext4_extent);
245#ifdef AGGRESSIVE_TEST
246 if (!check && size > 6)
247 size = 6;
248#endif
249 return size;
250}
251
252static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
253{
254 int size;
255
256 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
257 / sizeof(struct ext4_extent_idx);
258#ifdef AGGRESSIVE_TEST
259 if (!check && size > 5)
260 size = 5;
261#endif
262 return size;
263}
264
265static inline int ext4_ext_space_root(struct inode *inode, int check)
266{
267 int size;
268
269 size = sizeof(EXT4_I(inode)->i_data);
270 size -= sizeof(struct ext4_extent_header);
271 size /= sizeof(struct ext4_extent);
272#ifdef AGGRESSIVE_TEST
273 if (!check && size > 3)
274 size = 3;
275#endif
276 return size;
277}
278
279static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
280{
281 int size;
282
283 size = sizeof(EXT4_I(inode)->i_data);
284 size -= sizeof(struct ext4_extent_header);
285 size /= sizeof(struct ext4_extent_idx);
286#ifdef AGGRESSIVE_TEST
287 if (!check && size > 4)
288 size = 4;
289#endif
290 return size;
291}
292
293static inline int
294ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
295 struct ext4_ext_path **ppath, ext4_lblk_t lblk,
296 int nofail)
297{
298 struct ext4_ext_path *path = *ppath;
299 int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
300
301 return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
302 EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
303 EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
304 (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
305}
306
307/*
308 * Calculate the number of metadata blocks needed
309 * to allocate @blocks
310 * Worse case is one block per extent
311 */
312int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
313{
314 struct ext4_inode_info *ei = EXT4_I(inode);
315 int idxs;
316
317 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
318 / sizeof(struct ext4_extent_idx));
319
320 /*
321 * If the new delayed allocation block is contiguous with the
322 * previous da block, it can share index blocks with the
323 * previous block, so we only need to allocate a new index
324 * block every idxs leaf blocks. At ldxs**2 blocks, we need
325 * an additional index block, and at ldxs**3 blocks, yet
326 * another index blocks.
327 */
328 if (ei->i_da_metadata_calc_len &&
329 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
330 int num = 0;
331
332 if ((ei->i_da_metadata_calc_len % idxs) == 0)
333 num++;
334 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
335 num++;
336 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
337 num++;
338 ei->i_da_metadata_calc_len = 0;
339 } else
340 ei->i_da_metadata_calc_len++;
341 ei->i_da_metadata_calc_last_lblock++;
342 return num;
343 }
344
345 /*
346 * In the worst case we need a new set of index blocks at
347 * every level of the inode's extent tree.
348 */
349 ei->i_da_metadata_calc_len = 1;
350 ei->i_da_metadata_calc_last_lblock = lblock;
351 return ext_depth(inode) + 1;
352}
353
354static int
355ext4_ext_max_entries(struct inode *inode, int depth)
356{
357 int max;
358
359 if (depth == ext_depth(inode)) {
360 if (depth == 0)
361 max = ext4_ext_space_root(inode, 1);
362 else
363 max = ext4_ext_space_root_idx(inode, 1);
364 } else {
365 if (depth == 0)
366 max = ext4_ext_space_block(inode, 1);
367 else
368 max = ext4_ext_space_block_idx(inode, 1);
369 }
370
371 return max;
372}
373
374static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
375{
376 ext4_fsblk_t block = ext4_ext_pblock(ext);
377 int len = ext4_ext_get_actual_len(ext);
378 ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
379 ext4_lblk_t last = lblock + len - 1;
380
381 if (len == 0 || lblock > last)
382 return 0;
383 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
384}
385
386static int ext4_valid_extent_idx(struct inode *inode,
387 struct ext4_extent_idx *ext_idx)
388{
389 ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
390
391 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
392}
393
394static int ext4_valid_extent_entries(struct inode *inode,
395 struct ext4_extent_header *eh,
396 int depth)
397{
398 unsigned short entries;
399 if (eh->eh_entries == 0)
400 return 1;
401
402 entries = le16_to_cpu(eh->eh_entries);
403
404 if (depth == 0) {
405 /* leaf entries */
406 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
407 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
408 ext4_fsblk_t pblock = 0;
409 ext4_lblk_t lblock = 0;
410 ext4_lblk_t prev = 0;
411 int len = 0;
412 while (entries) {
413 if (!ext4_valid_extent(inode, ext))
414 return 0;
415
416 /* Check for overlapping extents */
417 lblock = le32_to_cpu(ext->ee_block);
418 len = ext4_ext_get_actual_len(ext);
419 if ((lblock <= prev) && prev) {
420 pblock = ext4_ext_pblock(ext);
421 es->s_last_error_block = cpu_to_le64(pblock);
422 return 0;
423 }
424 ext++;
425 entries--;
426 prev = lblock + len - 1;
427 }
428 } else {
429 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
430 while (entries) {
431 if (!ext4_valid_extent_idx(inode, ext_idx))
432 return 0;
433 ext_idx++;
434 entries--;
435 }
436 }
437 return 1;
438}
439
440static int __ext4_ext_check(const char *function, unsigned int line,
441 struct inode *inode, struct ext4_extent_header *eh,
442 int depth, ext4_fsblk_t pblk)
443{
444 const char *error_msg;
445 int max = 0, err = -EFSCORRUPTED;
446
447 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
448 error_msg = "invalid magic";
449 goto corrupted;
450 }
451 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
452 error_msg = "unexpected eh_depth";
453 goto corrupted;
454 }
455 if (unlikely(eh->eh_max == 0)) {
456 error_msg = "invalid eh_max";
457 goto corrupted;
458 }
459 max = ext4_ext_max_entries(inode, depth);
460 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
461 error_msg = "too large eh_max";
462 goto corrupted;
463 }
464 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
465 error_msg = "invalid eh_entries";
466 goto corrupted;
467 }
468 if (!ext4_valid_extent_entries(inode, eh, depth)) {
469 error_msg = "invalid extent entries";
470 goto corrupted;
471 }
472 /* Verify checksum on non-root extent tree nodes */
473 if (ext_depth(inode) != depth &&
474 !ext4_extent_block_csum_verify(inode, eh)) {
475 error_msg = "extent tree corrupted";
476 err = -EFSBADCRC;
477 goto corrupted;
478 }
479 return 0;
480
481corrupted:
482 ext4_error_inode(inode, function, line, 0,
483 "pblk %llu bad header/extent: %s - magic %x, "
484 "entries %u, max %u(%u), depth %u(%u)",
485 (unsigned long long) pblk, error_msg,
486 le16_to_cpu(eh->eh_magic),
487 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
488 max, le16_to_cpu(eh->eh_depth), depth);
489 return err;
490}
491
492#define ext4_ext_check(inode, eh, depth, pblk) \
493 __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
494
495int ext4_ext_check_inode(struct inode *inode)
496{
497 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
498}
499
500static struct buffer_head *
501__read_extent_tree_block(const char *function, unsigned int line,
502 struct inode *inode, ext4_fsblk_t pblk, int depth,
503 int flags)
504{
505 struct buffer_head *bh;
506 int err;
507
508 bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
509 if (unlikely(!bh))
510 return ERR_PTR(-ENOMEM);
511
512 if (!bh_uptodate_or_lock(bh)) {
513 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
514 err = bh_submit_read(bh);
515 if (err < 0)
516 goto errout;
517 }
518 if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
519 return bh;
520 err = __ext4_ext_check(function, line, inode,
521 ext_block_hdr(bh), depth, pblk);
522 if (err)
523 goto errout;
524 set_buffer_verified(bh);
525 /*
526 * If this is a leaf block, cache all of its entries
527 */
528 if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
529 struct ext4_extent_header *eh = ext_block_hdr(bh);
530 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
531 ext4_lblk_t prev = 0;
532 int i;
533
534 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
535 unsigned int status = EXTENT_STATUS_WRITTEN;
536 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
537 int len = ext4_ext_get_actual_len(ex);
538
539 if (prev && (prev != lblk))
540 ext4_es_cache_extent(inode, prev,
541 lblk - prev, ~0,
542 EXTENT_STATUS_HOLE);
543
544 if (ext4_ext_is_unwritten(ex))
545 status = EXTENT_STATUS_UNWRITTEN;
546 ext4_es_cache_extent(inode, lblk, len,
547 ext4_ext_pblock(ex), status);
548 prev = lblk + len;
549 }
550 }
551 return bh;
552errout:
553 put_bh(bh);
554 return ERR_PTR(err);
555
556}
557
558#define read_extent_tree_block(inode, pblk, depth, flags) \
559 __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \
560 (depth), (flags))
561
562/*
563 * This function is called to cache a file's extent information in the
564 * extent status tree
565 */
566int ext4_ext_precache(struct inode *inode)
567{
568 struct ext4_inode_info *ei = EXT4_I(inode);
569 struct ext4_ext_path *path = NULL;
570 struct buffer_head *bh;
571 int i = 0, depth, ret = 0;
572
573 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
574 return 0; /* not an extent-mapped inode */
575
576 down_read(&ei->i_data_sem);
577 depth = ext_depth(inode);
578
579 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
580 GFP_NOFS);
581 if (path == NULL) {
582 up_read(&ei->i_data_sem);
583 return -ENOMEM;
584 }
585
586 /* Don't cache anything if there are no external extent blocks */
587 if (depth == 0)
588 goto out;
589 path[0].p_hdr = ext_inode_hdr(inode);
590 ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
591 if (ret)
592 goto out;
593 path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
594 while (i >= 0) {
595 /*
596 * If this is a leaf block or we've reached the end of
597 * the index block, go up
598 */
599 if ((i == depth) ||
600 path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
601 brelse(path[i].p_bh);
602 path[i].p_bh = NULL;
603 i--;
604 continue;
605 }
606 bh = read_extent_tree_block(inode,
607 ext4_idx_pblock(path[i].p_idx++),
608 depth - i - 1,
609 EXT4_EX_FORCE_CACHE);
610 if (IS_ERR(bh)) {
611 ret = PTR_ERR(bh);
612 break;
613 }
614 i++;
615 path[i].p_bh = bh;
616 path[i].p_hdr = ext_block_hdr(bh);
617 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
618 }
619 ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
620out:
621 up_read(&ei->i_data_sem);
622 ext4_ext_drop_refs(path);
623 kfree(path);
624 return ret;
625}
626
627#ifdef EXT_DEBUG
628static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
629{
630 int k, l = path->p_depth;
631
632 ext_debug("path:");
633 for (k = 0; k <= l; k++, path++) {
634 if (path->p_idx) {
635 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
636 ext4_idx_pblock(path->p_idx));
637 } else if (path->p_ext) {
638 ext_debug(" %d:[%d]%d:%llu ",
639 le32_to_cpu(path->p_ext->ee_block),
640 ext4_ext_is_unwritten(path->p_ext),
641 ext4_ext_get_actual_len(path->p_ext),
642 ext4_ext_pblock(path->p_ext));
643 } else
644 ext_debug(" []");
645 }
646 ext_debug("\n");
647}
648
649static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
650{
651 int depth = ext_depth(inode);
652 struct ext4_extent_header *eh;
653 struct ext4_extent *ex;
654 int i;
655
656 if (!path)
657 return;
658
659 eh = path[depth].p_hdr;
660 ex = EXT_FIRST_EXTENT(eh);
661
662 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
663
664 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
665 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
666 ext4_ext_is_unwritten(ex),
667 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
668 }
669 ext_debug("\n");
670}
671
672static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
673 ext4_fsblk_t newblock, int level)
674{
675 int depth = ext_depth(inode);
676 struct ext4_extent *ex;
677
678 if (depth != level) {
679 struct ext4_extent_idx *idx;
680 idx = path[level].p_idx;
681 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
682 ext_debug("%d: move %d:%llu in new index %llu\n", level,
683 le32_to_cpu(idx->ei_block),
684 ext4_idx_pblock(idx),
685 newblock);
686 idx++;
687 }
688
689 return;
690 }
691
692 ex = path[depth].p_ext;
693 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
694 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
695 le32_to_cpu(ex->ee_block),
696 ext4_ext_pblock(ex),
697 ext4_ext_is_unwritten(ex),
698 ext4_ext_get_actual_len(ex),
699 newblock);
700 ex++;
701 }
702}
703
704#else
705#define ext4_ext_show_path(inode, path)
706#define ext4_ext_show_leaf(inode, path)
707#define ext4_ext_show_move(inode, path, newblock, level)
708#endif
709
710void ext4_ext_drop_refs(struct ext4_ext_path *path)
711{
712 int depth, i;
713
714 if (!path)
715 return;
716 depth = path->p_depth;
717 for (i = 0; i <= depth; i++, path++)
718 if (path->p_bh) {
719 brelse(path->p_bh);
720 path->p_bh = NULL;
721 }
722}
723
724/*
725 * ext4_ext_binsearch_idx:
726 * binary search for the closest index of the given block
727 * the header must be checked before calling this
728 */
729static void
730ext4_ext_binsearch_idx(struct inode *inode,
731 struct ext4_ext_path *path, ext4_lblk_t block)
732{
733 struct ext4_extent_header *eh = path->p_hdr;
734 struct ext4_extent_idx *r, *l, *m;
735
736
737 ext_debug("binsearch for %u(idx): ", block);
738
739 l = EXT_FIRST_INDEX(eh) + 1;
740 r = EXT_LAST_INDEX(eh);
741 while (l <= r) {
742 m = l + (r - l) / 2;
743 if (block < le32_to_cpu(m->ei_block))
744 r = m - 1;
745 else
746 l = m + 1;
747 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
748 m, le32_to_cpu(m->ei_block),
749 r, le32_to_cpu(r->ei_block));
750 }
751
752 path->p_idx = l - 1;
753 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
754 ext4_idx_pblock(path->p_idx));
755
756#ifdef CHECK_BINSEARCH
757 {
758 struct ext4_extent_idx *chix, *ix;
759 int k;
760
761 chix = ix = EXT_FIRST_INDEX(eh);
762 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
763 if (k != 0 &&
764 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
765 printk(KERN_DEBUG "k=%d, ix=0x%p, "
766 "first=0x%p\n", k,
767 ix, EXT_FIRST_INDEX(eh));
768 printk(KERN_DEBUG "%u <= %u\n",
769 le32_to_cpu(ix->ei_block),
770 le32_to_cpu(ix[-1].ei_block));
771 }
772 BUG_ON(k && le32_to_cpu(ix->ei_block)
773 <= le32_to_cpu(ix[-1].ei_block));
774 if (block < le32_to_cpu(ix->ei_block))
775 break;
776 chix = ix;
777 }
778 BUG_ON(chix != path->p_idx);
779 }
780#endif
781
782}
783
784/*
785 * ext4_ext_binsearch:
786 * binary search for closest extent of the given block
787 * the header must be checked before calling this
788 */
789static void
790ext4_ext_binsearch(struct inode *inode,
791 struct ext4_ext_path *path, ext4_lblk_t block)
792{
793 struct ext4_extent_header *eh = path->p_hdr;
794 struct ext4_extent *r, *l, *m;
795
796 if (eh->eh_entries == 0) {
797 /*
798 * this leaf is empty:
799 * we get such a leaf in split/add case
800 */
801 return;
802 }
803
804 ext_debug("binsearch for %u: ", block);
805
806 l = EXT_FIRST_EXTENT(eh) + 1;
807 r = EXT_LAST_EXTENT(eh);
808
809 while (l <= r) {
810 m = l + (r - l) / 2;
811 if (block < le32_to_cpu(m->ee_block))
812 r = m - 1;
813 else
814 l = m + 1;
815 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
816 m, le32_to_cpu(m->ee_block),
817 r, le32_to_cpu(r->ee_block));
818 }
819
820 path->p_ext = l - 1;
821 ext_debug(" -> %d:%llu:[%d]%d ",
822 le32_to_cpu(path->p_ext->ee_block),
823 ext4_ext_pblock(path->p_ext),
824 ext4_ext_is_unwritten(path->p_ext),
825 ext4_ext_get_actual_len(path->p_ext));
826
827#ifdef CHECK_BINSEARCH
828 {
829 struct ext4_extent *chex, *ex;
830 int k;
831
832 chex = ex = EXT_FIRST_EXTENT(eh);
833 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
834 BUG_ON(k && le32_to_cpu(ex->ee_block)
835 <= le32_to_cpu(ex[-1].ee_block));
836 if (block < le32_to_cpu(ex->ee_block))
837 break;
838 chex = ex;
839 }
840 BUG_ON(chex != path->p_ext);
841 }
842#endif
843
844}
845
846int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
847{
848 struct ext4_extent_header *eh;
849
850 eh = ext_inode_hdr(inode);
851 eh->eh_depth = 0;
852 eh->eh_entries = 0;
853 eh->eh_magic = EXT4_EXT_MAGIC;
854 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
855 ext4_mark_inode_dirty(handle, inode);
856 return 0;
857}
858
859struct ext4_ext_path *
860ext4_find_extent(struct inode *inode, ext4_lblk_t block,
861 struct ext4_ext_path **orig_path, int flags)
862{
863 struct ext4_extent_header *eh;
864 struct buffer_head *bh;
865 struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
866 short int depth, i, ppos = 0;
867 int ret;
868
869 eh = ext_inode_hdr(inode);
870 depth = ext_depth(inode);
871
872 if (path) {
873 ext4_ext_drop_refs(path);
874 if (depth > path[0].p_maxdepth) {
875 kfree(path);
876 *orig_path = path = NULL;
877 }
878 }
879 if (!path) {
880 /* account possible depth increase */
881 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
882 GFP_NOFS);
883 if (unlikely(!path))
884 return ERR_PTR(-ENOMEM);
885 path[0].p_maxdepth = depth + 1;
886 }
887 path[0].p_hdr = eh;
888 path[0].p_bh = NULL;
889
890 i = depth;
891 /* walk through the tree */
892 while (i) {
893 ext_debug("depth %d: num %d, max %d\n",
894 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
895
896 ext4_ext_binsearch_idx(inode, path + ppos, block);
897 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
898 path[ppos].p_depth = i;
899 path[ppos].p_ext = NULL;
900
901 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
902 flags);
903 if (IS_ERR(bh)) {
904 ret = PTR_ERR(bh);
905 goto err;
906 }
907
908 eh = ext_block_hdr(bh);
909 ppos++;
910 if (unlikely(ppos > depth)) {
911 put_bh(bh);
912 EXT4_ERROR_INODE(inode,
913 "ppos %d > depth %d", ppos, depth);
914 ret = -EFSCORRUPTED;
915 goto err;
916 }
917 path[ppos].p_bh = bh;
918 path[ppos].p_hdr = eh;
919 }
920
921 path[ppos].p_depth = i;
922 path[ppos].p_ext = NULL;
923 path[ppos].p_idx = NULL;
924
925 /* find extent */
926 ext4_ext_binsearch(inode, path + ppos, block);
927 /* if not an empty leaf */
928 if (path[ppos].p_ext)
929 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
930
931 ext4_ext_show_path(inode, path);
932
933 return path;
934
935err:
936 ext4_ext_drop_refs(path);
937 kfree(path);
938 if (orig_path)
939 *orig_path = NULL;
940 return ERR_PTR(ret);
941}
942
943/*
944 * ext4_ext_insert_index:
945 * insert new index [@logical;@ptr] into the block at @curp;
946 * check where to insert: before @curp or after @curp
947 */
948static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
949 struct ext4_ext_path *curp,
950 int logical, ext4_fsblk_t ptr)
951{
952 struct ext4_extent_idx *ix;
953 int len, err;
954
955 err = ext4_ext_get_access(handle, inode, curp);
956 if (err)
957 return err;
958
959 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
960 EXT4_ERROR_INODE(inode,
961 "logical %d == ei_block %d!",
962 logical, le32_to_cpu(curp->p_idx->ei_block));
963 return -EFSCORRUPTED;
964 }
965
966 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
967 >= le16_to_cpu(curp->p_hdr->eh_max))) {
968 EXT4_ERROR_INODE(inode,
969 "eh_entries %d >= eh_max %d!",
970 le16_to_cpu(curp->p_hdr->eh_entries),
971 le16_to_cpu(curp->p_hdr->eh_max));
972 return -EFSCORRUPTED;
973 }
974
975 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
976 /* insert after */
977 ext_debug("insert new index %d after: %llu\n", logical, ptr);
978 ix = curp->p_idx + 1;
979 } else {
980 /* insert before */
981 ext_debug("insert new index %d before: %llu\n", logical, ptr);
982 ix = curp->p_idx;
983 }
984
985 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
986 BUG_ON(len < 0);
987 if (len > 0) {
988 ext_debug("insert new index %d: "
989 "move %d indices from 0x%p to 0x%p\n",
990 logical, len, ix, ix + 1);
991 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
992 }
993
994 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
995 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
996 return -EFSCORRUPTED;
997 }
998
999 ix->ei_block = cpu_to_le32(logical);
1000 ext4_idx_store_pblock(ix, ptr);
1001 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1002
1003 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1004 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1005 return -EFSCORRUPTED;
1006 }
1007
1008 err = ext4_ext_dirty(handle, inode, curp);
1009 ext4_std_error(inode->i_sb, err);
1010
1011 return err;
1012}
1013
1014/*
1015 * ext4_ext_split:
1016 * inserts new subtree into the path, using free index entry
1017 * at depth @at:
1018 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1019 * - makes decision where to split
1020 * - moves remaining extents and index entries (right to the split point)
1021 * into the newly allocated blocks
1022 * - initializes subtree
1023 */
1024static int ext4_ext_split(handle_t *handle, struct inode *inode,
1025 unsigned int flags,
1026 struct ext4_ext_path *path,
1027 struct ext4_extent *newext, int at)
1028{
1029 struct buffer_head *bh = NULL;
1030 int depth = ext_depth(inode);
1031 struct ext4_extent_header *neh;
1032 struct ext4_extent_idx *fidx;
1033 int i = at, k, m, a;
1034 ext4_fsblk_t newblock, oldblock;
1035 __le32 border;
1036 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1037 int err = 0;
1038
1039 /* make decision: where to split? */
1040 /* FIXME: now decision is simplest: at current extent */
1041
1042 /* if current leaf will be split, then we should use
1043 * border from split point */
1044 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1045 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1046 return -EFSCORRUPTED;
1047 }
1048 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1049 border = path[depth].p_ext[1].ee_block;
1050 ext_debug("leaf will be split."
1051 " next leaf starts at %d\n",
1052 le32_to_cpu(border));
1053 } else {
1054 border = newext->ee_block;
1055 ext_debug("leaf will be added."
1056 " next leaf starts at %d\n",
1057 le32_to_cpu(border));
1058 }
1059
1060 /*
1061 * If error occurs, then we break processing
1062 * and mark filesystem read-only. index won't
1063 * be inserted and tree will be in consistent
1064 * state. Next mount will repair buffers too.
1065 */
1066
1067 /*
1068 * Get array to track all allocated blocks.
1069 * We need this to handle errors and free blocks
1070 * upon them.
1071 */
1072 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1073 if (!ablocks)
1074 return -ENOMEM;
1075
1076 /* allocate all needed blocks */
1077 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1078 for (a = 0; a < depth - at; a++) {
1079 newblock = ext4_ext_new_meta_block(handle, inode, path,
1080 newext, &err, flags);
1081 if (newblock == 0)
1082 goto cleanup;
1083 ablocks[a] = newblock;
1084 }
1085
1086 /* initialize new leaf */
1087 newblock = ablocks[--a];
1088 if (unlikely(newblock == 0)) {
1089 EXT4_ERROR_INODE(inode, "newblock == 0!");
1090 err = -EFSCORRUPTED;
1091 goto cleanup;
1092 }
1093 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1094 if (unlikely(!bh)) {
1095 err = -ENOMEM;
1096 goto cleanup;
1097 }
1098 lock_buffer(bh);
1099
1100 err = ext4_journal_get_create_access(handle, bh);
1101 if (err)
1102 goto cleanup;
1103
1104 neh = ext_block_hdr(bh);
1105 neh->eh_entries = 0;
1106 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1107 neh->eh_magic = EXT4_EXT_MAGIC;
1108 neh->eh_depth = 0;
1109
1110 /* move remainder of path[depth] to the new leaf */
1111 if (unlikely(path[depth].p_hdr->eh_entries !=
1112 path[depth].p_hdr->eh_max)) {
1113 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1114 path[depth].p_hdr->eh_entries,
1115 path[depth].p_hdr->eh_max);
1116 err = -EFSCORRUPTED;
1117 goto cleanup;
1118 }
1119 /* start copy from next extent */
1120 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1121 ext4_ext_show_move(inode, path, newblock, depth);
1122 if (m) {
1123 struct ext4_extent *ex;
1124 ex = EXT_FIRST_EXTENT(neh);
1125 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1126 le16_add_cpu(&neh->eh_entries, m);
1127 }
1128
1129 ext4_extent_block_csum_set(inode, neh);
1130 set_buffer_uptodate(bh);
1131 unlock_buffer(bh);
1132
1133 err = ext4_handle_dirty_metadata(handle, inode, bh);
1134 if (err)
1135 goto cleanup;
1136 brelse(bh);
1137 bh = NULL;
1138
1139 /* correct old leaf */
1140 if (m) {
1141 err = ext4_ext_get_access(handle, inode, path + depth);
1142 if (err)
1143 goto cleanup;
1144 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1145 err = ext4_ext_dirty(handle, inode, path + depth);
1146 if (err)
1147 goto cleanup;
1148
1149 }
1150
1151 /* create intermediate indexes */
1152 k = depth - at - 1;
1153 if (unlikely(k < 0)) {
1154 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1155 err = -EFSCORRUPTED;
1156 goto cleanup;
1157 }
1158 if (k)
1159 ext_debug("create %d intermediate indices\n", k);
1160 /* insert new index into current index block */
1161 /* current depth stored in i var */
1162 i = depth - 1;
1163 while (k--) {
1164 oldblock = newblock;
1165 newblock = ablocks[--a];
1166 bh = sb_getblk(inode->i_sb, newblock);
1167 if (unlikely(!bh)) {
1168 err = -ENOMEM;
1169 goto cleanup;
1170 }
1171 lock_buffer(bh);
1172
1173 err = ext4_journal_get_create_access(handle, bh);
1174 if (err)
1175 goto cleanup;
1176
1177 neh = ext_block_hdr(bh);
1178 neh->eh_entries = cpu_to_le16(1);
1179 neh->eh_magic = EXT4_EXT_MAGIC;
1180 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1181 neh->eh_depth = cpu_to_le16(depth - i);
1182 fidx = EXT_FIRST_INDEX(neh);
1183 fidx->ei_block = border;
1184 ext4_idx_store_pblock(fidx, oldblock);
1185
1186 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1187 i, newblock, le32_to_cpu(border), oldblock);
1188
1189 /* move remainder of path[i] to the new index block */
1190 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1191 EXT_LAST_INDEX(path[i].p_hdr))) {
1192 EXT4_ERROR_INODE(inode,
1193 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1194 le32_to_cpu(path[i].p_ext->ee_block));
1195 err = -EFSCORRUPTED;
1196 goto cleanup;
1197 }
1198 /* start copy indexes */
1199 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1200 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1201 EXT_MAX_INDEX(path[i].p_hdr));
1202 ext4_ext_show_move(inode, path, newblock, i);
1203 if (m) {
1204 memmove(++fidx, path[i].p_idx,
1205 sizeof(struct ext4_extent_idx) * m);
1206 le16_add_cpu(&neh->eh_entries, m);
1207 }
1208 ext4_extent_block_csum_set(inode, neh);
1209 set_buffer_uptodate(bh);
1210 unlock_buffer(bh);
1211
1212 err = ext4_handle_dirty_metadata(handle, inode, bh);
1213 if (err)
1214 goto cleanup;
1215 brelse(bh);
1216 bh = NULL;
1217
1218 /* correct old index */
1219 if (m) {
1220 err = ext4_ext_get_access(handle, inode, path + i);
1221 if (err)
1222 goto cleanup;
1223 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1224 err = ext4_ext_dirty(handle, inode, path + i);
1225 if (err)
1226 goto cleanup;
1227 }
1228
1229 i--;
1230 }
1231
1232 /* insert new index */
1233 err = ext4_ext_insert_index(handle, inode, path + at,
1234 le32_to_cpu(border), newblock);
1235
1236cleanup:
1237 if (bh) {
1238 if (buffer_locked(bh))
1239 unlock_buffer(bh);
1240 brelse(bh);
1241 }
1242
1243 if (err) {
1244 /* free all allocated blocks in error case */
1245 for (i = 0; i < depth; i++) {
1246 if (!ablocks[i])
1247 continue;
1248 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1249 EXT4_FREE_BLOCKS_METADATA);
1250 }
1251 }
1252 kfree(ablocks);
1253
1254 return err;
1255}
1256
1257/*
1258 * ext4_ext_grow_indepth:
1259 * implements tree growing procedure:
1260 * - allocates new block
1261 * - moves top-level data (index block or leaf) into the new block
1262 * - initializes new top-level, creating index that points to the
1263 * just created block
1264 */
1265static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1266 unsigned int flags)
1267{
1268 struct ext4_extent_header *neh;
1269 struct buffer_head *bh;
1270 ext4_fsblk_t newblock, goal = 0;
1271 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1272 int err = 0;
1273
1274 /* Try to prepend new index to old one */
1275 if (ext_depth(inode))
1276 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1277 if (goal > le32_to_cpu(es->s_first_data_block)) {
1278 flags |= EXT4_MB_HINT_TRY_GOAL;
1279 goal--;
1280 } else
1281 goal = ext4_inode_to_goal_block(inode);
1282 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1283 NULL, &err);
1284 if (newblock == 0)
1285 return err;
1286
1287 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1288 if (unlikely(!bh))
1289 return -ENOMEM;
1290 lock_buffer(bh);
1291
1292 err = ext4_journal_get_create_access(handle, bh);
1293 if (err) {
1294 unlock_buffer(bh);
1295 goto out;
1296 }
1297
1298 /* move top-level index/leaf into new block */
1299 memmove(bh->b_data, EXT4_I(inode)->i_data,
1300 sizeof(EXT4_I(inode)->i_data));
1301
1302 /* set size of new block */
1303 neh = ext_block_hdr(bh);
1304 /* old root could have indexes or leaves
1305 * so calculate e_max right way */
1306 if (ext_depth(inode))
1307 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1308 else
1309 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1310 neh->eh_magic = EXT4_EXT_MAGIC;
1311 ext4_extent_block_csum_set(inode, neh);
1312 set_buffer_uptodate(bh);
1313 unlock_buffer(bh);
1314
1315 err = ext4_handle_dirty_metadata(handle, inode, bh);
1316 if (err)
1317 goto out;
1318
1319 /* Update top-level index: num,max,pointer */
1320 neh = ext_inode_hdr(inode);
1321 neh->eh_entries = cpu_to_le16(1);
1322 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1323 if (neh->eh_depth == 0) {
1324 /* Root extent block becomes index block */
1325 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1326 EXT_FIRST_INDEX(neh)->ei_block =
1327 EXT_FIRST_EXTENT(neh)->ee_block;
1328 }
1329 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1330 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1331 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1332 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1333
1334 le16_add_cpu(&neh->eh_depth, 1);
1335 ext4_mark_inode_dirty(handle, inode);
1336out:
1337 brelse(bh);
1338
1339 return err;
1340}
1341
1342/*
1343 * ext4_ext_create_new_leaf:
1344 * finds empty index and adds new leaf.
1345 * if no free index is found, then it requests in-depth growing.
1346 */
1347static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1348 unsigned int mb_flags,
1349 unsigned int gb_flags,
1350 struct ext4_ext_path **ppath,
1351 struct ext4_extent *newext)
1352{
1353 struct ext4_ext_path *path = *ppath;
1354 struct ext4_ext_path *curp;
1355 int depth, i, err = 0;
1356
1357repeat:
1358 i = depth = ext_depth(inode);
1359
1360 /* walk up to the tree and look for free index entry */
1361 curp = path + depth;
1362 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1363 i--;
1364 curp--;
1365 }
1366
1367 /* we use already allocated block for index block,
1368 * so subsequent data blocks should be contiguous */
1369 if (EXT_HAS_FREE_INDEX(curp)) {
1370 /* if we found index with free entry, then use that
1371 * entry: create all needed subtree and add new leaf */
1372 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1373 if (err)
1374 goto out;
1375
1376 /* refill path */
1377 path = ext4_find_extent(inode,
1378 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1379 ppath, gb_flags);
1380 if (IS_ERR(path))
1381 err = PTR_ERR(path);
1382 } else {
1383 /* tree is full, time to grow in depth */
1384 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1385 if (err)
1386 goto out;
1387
1388 /* refill path */
1389 path = ext4_find_extent(inode,
1390 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1391 ppath, gb_flags);
1392 if (IS_ERR(path)) {
1393 err = PTR_ERR(path);
1394 goto out;
1395 }
1396
1397 /*
1398 * only first (depth 0 -> 1) produces free space;
1399 * in all other cases we have to split the grown tree
1400 */
1401 depth = ext_depth(inode);
1402 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1403 /* now we need to split */
1404 goto repeat;
1405 }
1406 }
1407
1408out:
1409 return err;
1410}
1411
1412/*
1413 * search the closest allocated block to the left for *logical
1414 * and returns it at @logical + it's physical address at @phys
1415 * if *logical is the smallest allocated block, the function
1416 * returns 0 at @phys
1417 * return value contains 0 (success) or error code
1418 */
1419static int ext4_ext_search_left(struct inode *inode,
1420 struct ext4_ext_path *path,
1421 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1422{
1423 struct ext4_extent_idx *ix;
1424 struct ext4_extent *ex;
1425 int depth, ee_len;
1426
1427 if (unlikely(path == NULL)) {
1428 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1429 return -EFSCORRUPTED;
1430 }
1431 depth = path->p_depth;
1432 *phys = 0;
1433
1434 if (depth == 0 && path->p_ext == NULL)
1435 return 0;
1436
1437 /* usually extent in the path covers blocks smaller
1438 * then *logical, but it can be that extent is the
1439 * first one in the file */
1440
1441 ex = path[depth].p_ext;
1442 ee_len = ext4_ext_get_actual_len(ex);
1443 if (*logical < le32_to_cpu(ex->ee_block)) {
1444 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1445 EXT4_ERROR_INODE(inode,
1446 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1447 *logical, le32_to_cpu(ex->ee_block));
1448 return -EFSCORRUPTED;
1449 }
1450 while (--depth >= 0) {
1451 ix = path[depth].p_idx;
1452 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1453 EXT4_ERROR_INODE(inode,
1454 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1455 ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1456 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1457 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1458 depth);
1459 return -EFSCORRUPTED;
1460 }
1461 }
1462 return 0;
1463 }
1464
1465 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1466 EXT4_ERROR_INODE(inode,
1467 "logical %d < ee_block %d + ee_len %d!",
1468 *logical, le32_to_cpu(ex->ee_block), ee_len);
1469 return -EFSCORRUPTED;
1470 }
1471
1472 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1473 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1474 return 0;
1475}
1476
1477/*
1478 * search the closest allocated block to the right for *logical
1479 * and returns it at @logical + it's physical address at @phys
1480 * if *logical is the largest allocated block, the function
1481 * returns 0 at @phys
1482 * return value contains 0 (success) or error code
1483 */
1484static int ext4_ext_search_right(struct inode *inode,
1485 struct ext4_ext_path *path,
1486 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1487 struct ext4_extent **ret_ex)
1488{
1489 struct buffer_head *bh = NULL;
1490 struct ext4_extent_header *eh;
1491 struct ext4_extent_idx *ix;
1492 struct ext4_extent *ex;
1493 ext4_fsblk_t block;
1494 int depth; /* Note, NOT eh_depth; depth from top of tree */
1495 int ee_len;
1496
1497 if (unlikely(path == NULL)) {
1498 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1499 return -EFSCORRUPTED;
1500 }
1501 depth = path->p_depth;
1502 *phys = 0;
1503
1504 if (depth == 0 && path->p_ext == NULL)
1505 return 0;
1506
1507 /* usually extent in the path covers blocks smaller
1508 * then *logical, but it can be that extent is the
1509 * first one in the file */
1510
1511 ex = path[depth].p_ext;
1512 ee_len = ext4_ext_get_actual_len(ex);
1513 if (*logical < le32_to_cpu(ex->ee_block)) {
1514 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1515 EXT4_ERROR_INODE(inode,
1516 "first_extent(path[%d].p_hdr) != ex",
1517 depth);
1518 return -EFSCORRUPTED;
1519 }
1520 while (--depth >= 0) {
1521 ix = path[depth].p_idx;
1522 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1523 EXT4_ERROR_INODE(inode,
1524 "ix != EXT_FIRST_INDEX *logical %d!",
1525 *logical);
1526 return -EFSCORRUPTED;
1527 }
1528 }
1529 goto found_extent;
1530 }
1531
1532 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1533 EXT4_ERROR_INODE(inode,
1534 "logical %d < ee_block %d + ee_len %d!",
1535 *logical, le32_to_cpu(ex->ee_block), ee_len);
1536 return -EFSCORRUPTED;
1537 }
1538
1539 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1540 /* next allocated block in this leaf */
1541 ex++;
1542 goto found_extent;
1543 }
1544
1545 /* go up and search for index to the right */
1546 while (--depth >= 0) {
1547 ix = path[depth].p_idx;
1548 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1549 goto got_index;
1550 }
1551
1552 /* we've gone up to the root and found no index to the right */
1553 return 0;
1554
1555got_index:
1556 /* we've found index to the right, let's
1557 * follow it and find the closest allocated
1558 * block to the right */
1559 ix++;
1560 block = ext4_idx_pblock(ix);
1561 while (++depth < path->p_depth) {
1562 /* subtract from p_depth to get proper eh_depth */
1563 bh = read_extent_tree_block(inode, block,
1564 path->p_depth - depth, 0);
1565 if (IS_ERR(bh))
1566 return PTR_ERR(bh);
1567 eh = ext_block_hdr(bh);
1568 ix = EXT_FIRST_INDEX(eh);
1569 block = ext4_idx_pblock(ix);
1570 put_bh(bh);
1571 }
1572
1573 bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1574 if (IS_ERR(bh))
1575 return PTR_ERR(bh);
1576 eh = ext_block_hdr(bh);
1577 ex = EXT_FIRST_EXTENT(eh);
1578found_extent:
1579 *logical = le32_to_cpu(ex->ee_block);
1580 *phys = ext4_ext_pblock(ex);
1581 *ret_ex = ex;
1582 if (bh)
1583 put_bh(bh);
1584 return 0;
1585}
1586
1587/*
1588 * ext4_ext_next_allocated_block:
1589 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1590 * NOTE: it considers block number from index entry as
1591 * allocated block. Thus, index entries have to be consistent
1592 * with leaves.
1593 */
1594ext4_lblk_t
1595ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1596{
1597 int depth;
1598
1599 BUG_ON(path == NULL);
1600 depth = path->p_depth;
1601
1602 if (depth == 0 && path->p_ext == NULL)
1603 return EXT_MAX_BLOCKS;
1604
1605 while (depth >= 0) {
1606 if (depth == path->p_depth) {
1607 /* leaf */
1608 if (path[depth].p_ext &&
1609 path[depth].p_ext !=
1610 EXT_LAST_EXTENT(path[depth].p_hdr))
1611 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1612 } else {
1613 /* index */
1614 if (path[depth].p_idx !=
1615 EXT_LAST_INDEX(path[depth].p_hdr))
1616 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1617 }
1618 depth--;
1619 }
1620
1621 return EXT_MAX_BLOCKS;
1622}
1623
1624/*
1625 * ext4_ext_next_leaf_block:
1626 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1627 */
1628static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1629{
1630 int depth;
1631
1632 BUG_ON(path == NULL);
1633 depth = path->p_depth;
1634
1635 /* zero-tree has no leaf blocks at all */
1636 if (depth == 0)
1637 return EXT_MAX_BLOCKS;
1638
1639 /* go to index block */
1640 depth--;
1641
1642 while (depth >= 0) {
1643 if (path[depth].p_idx !=
1644 EXT_LAST_INDEX(path[depth].p_hdr))
1645 return (ext4_lblk_t)
1646 le32_to_cpu(path[depth].p_idx[1].ei_block);
1647 depth--;
1648 }
1649
1650 return EXT_MAX_BLOCKS;
1651}
1652
1653/*
1654 * ext4_ext_correct_indexes:
1655 * if leaf gets modified and modified extent is first in the leaf,
1656 * then we have to correct all indexes above.
1657 * TODO: do we need to correct tree in all cases?
1658 */
1659static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1660 struct ext4_ext_path *path)
1661{
1662 struct ext4_extent_header *eh;
1663 int depth = ext_depth(inode);
1664 struct ext4_extent *ex;
1665 __le32 border;
1666 int k, err = 0;
1667
1668 eh = path[depth].p_hdr;
1669 ex = path[depth].p_ext;
1670
1671 if (unlikely(ex == NULL || eh == NULL)) {
1672 EXT4_ERROR_INODE(inode,
1673 "ex %p == NULL or eh %p == NULL", ex, eh);
1674 return -EFSCORRUPTED;
1675 }
1676
1677 if (depth == 0) {
1678 /* there is no tree at all */
1679 return 0;
1680 }
1681
1682 if (ex != EXT_FIRST_EXTENT(eh)) {
1683 /* we correct tree if first leaf got modified only */
1684 return 0;
1685 }
1686
1687 /*
1688 * TODO: we need correction if border is smaller than current one
1689 */
1690 k = depth - 1;
1691 border = path[depth].p_ext->ee_block;
1692 err = ext4_ext_get_access(handle, inode, path + k);
1693 if (err)
1694 return err;
1695 path[k].p_idx->ei_block = border;
1696 err = ext4_ext_dirty(handle, inode, path + k);
1697 if (err)
1698 return err;
1699
1700 while (k--) {
1701 /* change all left-side indexes */
1702 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1703 break;
1704 err = ext4_ext_get_access(handle, inode, path + k);
1705 if (err)
1706 break;
1707 path[k].p_idx->ei_block = border;
1708 err = ext4_ext_dirty(handle, inode, path + k);
1709 if (err)
1710 break;
1711 }
1712
1713 return err;
1714}
1715
1716int
1717ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1718 struct ext4_extent *ex2)
1719{
1720 unsigned short ext1_ee_len, ext2_ee_len;
1721
1722 if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1723 return 0;
1724
1725 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1726 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1727
1728 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1729 le32_to_cpu(ex2->ee_block))
1730 return 0;
1731
1732 /*
1733 * To allow future support for preallocated extents to be added
1734 * as an RO_COMPAT feature, refuse to merge to extents if
1735 * this can result in the top bit of ee_len being set.
1736 */
1737 if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1738 return 0;
1739 /*
1740 * The check for IO to unwritten extent is somewhat racy as we
1741 * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1742 * dropping i_data_sem. But reserved blocks should save us in that
1743 * case.
1744 */
1745 if (ext4_ext_is_unwritten(ex1) &&
1746 (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1747 atomic_read(&EXT4_I(inode)->i_unwritten) ||
1748 (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1749 return 0;
1750#ifdef AGGRESSIVE_TEST
1751 if (ext1_ee_len >= 4)
1752 return 0;
1753#endif
1754
1755 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1756 return 1;
1757 return 0;
1758}
1759
1760/*
1761 * This function tries to merge the "ex" extent to the next extent in the tree.
1762 * It always tries to merge towards right. If you want to merge towards
1763 * left, pass "ex - 1" as argument instead of "ex".
1764 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1765 * 1 if they got merged.
1766 */
1767static int ext4_ext_try_to_merge_right(struct inode *inode,
1768 struct ext4_ext_path *path,
1769 struct ext4_extent *ex)
1770{
1771 struct ext4_extent_header *eh;
1772 unsigned int depth, len;
1773 int merge_done = 0, unwritten;
1774
1775 depth = ext_depth(inode);
1776 BUG_ON(path[depth].p_hdr == NULL);
1777 eh = path[depth].p_hdr;
1778
1779 while (ex < EXT_LAST_EXTENT(eh)) {
1780 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1781 break;
1782 /* merge with next extent! */
1783 unwritten = ext4_ext_is_unwritten(ex);
1784 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1785 + ext4_ext_get_actual_len(ex + 1));
1786 if (unwritten)
1787 ext4_ext_mark_unwritten(ex);
1788
1789 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1790 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1791 * sizeof(struct ext4_extent);
1792 memmove(ex + 1, ex + 2, len);
1793 }
1794 le16_add_cpu(&eh->eh_entries, -1);
1795 merge_done = 1;
1796 WARN_ON(eh->eh_entries == 0);
1797 if (!eh->eh_entries)
1798 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1799 }
1800
1801 return merge_done;
1802}
1803
1804/*
1805 * This function does a very simple check to see if we can collapse
1806 * an extent tree with a single extent tree leaf block into the inode.
1807 */
1808static void ext4_ext_try_to_merge_up(handle_t *handle,
1809 struct inode *inode,
1810 struct ext4_ext_path *path)
1811{
1812 size_t s;
1813 unsigned max_root = ext4_ext_space_root(inode, 0);
1814 ext4_fsblk_t blk;
1815
1816 if ((path[0].p_depth != 1) ||
1817 (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1818 (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1819 return;
1820
1821 /*
1822 * We need to modify the block allocation bitmap and the block
1823 * group descriptor to release the extent tree block. If we
1824 * can't get the journal credits, give up.
1825 */
1826 if (ext4_journal_extend(handle, 2))
1827 return;
1828
1829 /*
1830 * Copy the extent data up to the inode
1831 */
1832 blk = ext4_idx_pblock(path[0].p_idx);
1833 s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1834 sizeof(struct ext4_extent_idx);
1835 s += sizeof(struct ext4_extent_header);
1836
1837 path[1].p_maxdepth = path[0].p_maxdepth;
1838 memcpy(path[0].p_hdr, path[1].p_hdr, s);
1839 path[0].p_depth = 0;
1840 path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1841 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1842 path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1843
1844 brelse(path[1].p_bh);
1845 ext4_free_blocks(handle, inode, NULL, blk, 1,
1846 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1847}
1848
1849/*
1850 * This function tries to merge the @ex extent to neighbours in the tree.
1851 * return 1 if merge left else 0.
1852 */
1853static void ext4_ext_try_to_merge(handle_t *handle,
1854 struct inode *inode,
1855 struct ext4_ext_path *path,
1856 struct ext4_extent *ex) {
1857 struct ext4_extent_header *eh;
1858 unsigned int depth;
1859 int merge_done = 0;
1860
1861 depth = ext_depth(inode);
1862 BUG_ON(path[depth].p_hdr == NULL);
1863 eh = path[depth].p_hdr;
1864
1865 if (ex > EXT_FIRST_EXTENT(eh))
1866 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1867
1868 if (!merge_done)
1869 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1870
1871 ext4_ext_try_to_merge_up(handle, inode, path);
1872}
1873
1874/*
1875 * check if a portion of the "newext" extent overlaps with an
1876 * existing extent.
1877 *
1878 * If there is an overlap discovered, it updates the length of the newext
1879 * such that there will be no overlap, and then returns 1.
1880 * If there is no overlap found, it returns 0.
1881 */
1882static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1883 struct inode *inode,
1884 struct ext4_extent *newext,
1885 struct ext4_ext_path *path)
1886{
1887 ext4_lblk_t b1, b2;
1888 unsigned int depth, len1;
1889 unsigned int ret = 0;
1890
1891 b1 = le32_to_cpu(newext->ee_block);
1892 len1 = ext4_ext_get_actual_len(newext);
1893 depth = ext_depth(inode);
1894 if (!path[depth].p_ext)
1895 goto out;
1896 b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1897
1898 /*
1899 * get the next allocated block if the extent in the path
1900 * is before the requested block(s)
1901 */
1902 if (b2 < b1) {
1903 b2 = ext4_ext_next_allocated_block(path);
1904 if (b2 == EXT_MAX_BLOCKS)
1905 goto out;
1906 b2 = EXT4_LBLK_CMASK(sbi, b2);
1907 }
1908
1909 /* check for wrap through zero on extent logical start block*/
1910 if (b1 + len1 < b1) {
1911 len1 = EXT_MAX_BLOCKS - b1;
1912 newext->ee_len = cpu_to_le16(len1);
1913 ret = 1;
1914 }
1915
1916 /* check for overlap */
1917 if (b1 + len1 > b2) {
1918 newext->ee_len = cpu_to_le16(b2 - b1);
1919 ret = 1;
1920 }
1921out:
1922 return ret;
1923}
1924
1925/*
1926 * ext4_ext_insert_extent:
1927 * tries to merge requsted extent into the existing extent or
1928 * inserts requested extent as new one into the tree,
1929 * creating new leaf in the no-space case.
1930 */
1931int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1932 struct ext4_ext_path **ppath,
1933 struct ext4_extent *newext, int gb_flags)
1934{
1935 struct ext4_ext_path *path = *ppath;
1936 struct ext4_extent_header *eh;
1937 struct ext4_extent *ex, *fex;
1938 struct ext4_extent *nearex; /* nearest extent */
1939 struct ext4_ext_path *npath = NULL;
1940 int depth, len, err;
1941 ext4_lblk_t next;
1942 int mb_flags = 0, unwritten;
1943
1944 if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1945 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1946 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1947 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1948 return -EFSCORRUPTED;
1949 }
1950 depth = ext_depth(inode);
1951 ex = path[depth].p_ext;
1952 eh = path[depth].p_hdr;
1953 if (unlikely(path[depth].p_hdr == NULL)) {
1954 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1955 return -EFSCORRUPTED;
1956 }
1957
1958 /* try to insert block into found extent and return */
1959 if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1960
1961 /*
1962 * Try to see whether we should rather test the extent on
1963 * right from ex, or from the left of ex. This is because
1964 * ext4_find_extent() can return either extent on the
1965 * left, or on the right from the searched position. This
1966 * will make merging more effective.
1967 */
1968 if (ex < EXT_LAST_EXTENT(eh) &&
1969 (le32_to_cpu(ex->ee_block) +
1970 ext4_ext_get_actual_len(ex) <
1971 le32_to_cpu(newext->ee_block))) {
1972 ex += 1;
1973 goto prepend;
1974 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1975 (le32_to_cpu(newext->ee_block) +
1976 ext4_ext_get_actual_len(newext) <
1977 le32_to_cpu(ex->ee_block)))
1978 ex -= 1;
1979
1980 /* Try to append newex to the ex */
1981 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1982 ext_debug("append [%d]%d block to %u:[%d]%d"
1983 "(from %llu)\n",
1984 ext4_ext_is_unwritten(newext),
1985 ext4_ext_get_actual_len(newext),
1986 le32_to_cpu(ex->ee_block),
1987 ext4_ext_is_unwritten(ex),
1988 ext4_ext_get_actual_len(ex),
1989 ext4_ext_pblock(ex));
1990 err = ext4_ext_get_access(handle, inode,
1991 path + depth);
1992 if (err)
1993 return err;
1994 unwritten = ext4_ext_is_unwritten(ex);
1995 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1996 + ext4_ext_get_actual_len(newext));
1997 if (unwritten)
1998 ext4_ext_mark_unwritten(ex);
1999 eh = path[depth].p_hdr;
2000 nearex = ex;
2001 goto merge;
2002 }
2003
2004prepend:
2005 /* Try to prepend newex to the ex */
2006 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2007 ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2008 "(from %llu)\n",
2009 le32_to_cpu(newext->ee_block),
2010 ext4_ext_is_unwritten(newext),
2011 ext4_ext_get_actual_len(newext),
2012 le32_to_cpu(ex->ee_block),
2013 ext4_ext_is_unwritten(ex),
2014 ext4_ext_get_actual_len(ex),
2015 ext4_ext_pblock(ex));
2016 err = ext4_ext_get_access(handle, inode,
2017 path + depth);
2018 if (err)
2019 return err;
2020
2021 unwritten = ext4_ext_is_unwritten(ex);
2022 ex->ee_block = newext->ee_block;
2023 ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2024 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2025 + ext4_ext_get_actual_len(newext));
2026 if (unwritten)
2027 ext4_ext_mark_unwritten(ex);
2028 eh = path[depth].p_hdr;
2029 nearex = ex;
2030 goto merge;
2031 }
2032 }
2033
2034 depth = ext_depth(inode);
2035 eh = path[depth].p_hdr;
2036 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2037 goto has_space;
2038
2039 /* probably next leaf has space for us? */
2040 fex = EXT_LAST_EXTENT(eh);
2041 next = EXT_MAX_BLOCKS;
2042 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2043 next = ext4_ext_next_leaf_block(path);
2044 if (next != EXT_MAX_BLOCKS) {
2045 ext_debug("next leaf block - %u\n", next);
2046 BUG_ON(npath != NULL);
2047 npath = ext4_find_extent(inode, next, NULL, 0);
2048 if (IS_ERR(npath))
2049 return PTR_ERR(npath);
2050 BUG_ON(npath->p_depth != path->p_depth);
2051 eh = npath[depth].p_hdr;
2052 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2053 ext_debug("next leaf isn't full(%d)\n",
2054 le16_to_cpu(eh->eh_entries));
2055 path = npath;
2056 goto has_space;
2057 }
2058 ext_debug("next leaf has no free space(%d,%d)\n",
2059 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2060 }
2061
2062 /*
2063 * There is no free space in the found leaf.
2064 * We're gonna add a new leaf in the tree.
2065 */
2066 if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2067 mb_flags |= EXT4_MB_USE_RESERVED;
2068 err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2069 ppath, newext);
2070 if (err)
2071 goto cleanup;
2072 depth = ext_depth(inode);
2073 eh = path[depth].p_hdr;
2074
2075has_space:
2076 nearex = path[depth].p_ext;
2077
2078 err = ext4_ext_get_access(handle, inode, path + depth);
2079 if (err)
2080 goto cleanup;
2081
2082 if (!nearex) {
2083 /* there is no extent in this leaf, create first one */
2084 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2085 le32_to_cpu(newext->ee_block),
2086 ext4_ext_pblock(newext),
2087 ext4_ext_is_unwritten(newext),
2088 ext4_ext_get_actual_len(newext));
2089 nearex = EXT_FIRST_EXTENT(eh);
2090 } else {
2091 if (le32_to_cpu(newext->ee_block)
2092 > le32_to_cpu(nearex->ee_block)) {
2093 /* Insert after */
2094 ext_debug("insert %u:%llu:[%d]%d before: "
2095 "nearest %p\n",
2096 le32_to_cpu(newext->ee_block),
2097 ext4_ext_pblock(newext),
2098 ext4_ext_is_unwritten(newext),
2099 ext4_ext_get_actual_len(newext),
2100 nearex);
2101 nearex++;
2102 } else {
2103 /* Insert before */
2104 BUG_ON(newext->ee_block == nearex->ee_block);
2105 ext_debug("insert %u:%llu:[%d]%d after: "
2106 "nearest %p\n",
2107 le32_to_cpu(newext->ee_block),
2108 ext4_ext_pblock(newext),
2109 ext4_ext_is_unwritten(newext),
2110 ext4_ext_get_actual_len(newext),
2111 nearex);
2112 }
2113 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2114 if (len > 0) {
2115 ext_debug("insert %u:%llu:[%d]%d: "
2116 "move %d extents from 0x%p to 0x%p\n",
2117 le32_to_cpu(newext->ee_block),
2118 ext4_ext_pblock(newext),
2119 ext4_ext_is_unwritten(newext),
2120 ext4_ext_get_actual_len(newext),
2121 len, nearex, nearex + 1);
2122 memmove(nearex + 1, nearex,
2123 len * sizeof(struct ext4_extent));
2124 }
2125 }
2126
2127 le16_add_cpu(&eh->eh_entries, 1);
2128 path[depth].p_ext = nearex;
2129 nearex->ee_block = newext->ee_block;
2130 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2131 nearex->ee_len = newext->ee_len;
2132
2133merge:
2134 /* try to merge extents */
2135 if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2136 ext4_ext_try_to_merge(handle, inode, path, nearex);
2137
2138
2139 /* time to correct all indexes above */
2140 err = ext4_ext_correct_indexes(handle, inode, path);
2141 if (err)
2142 goto cleanup;
2143
2144 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2145
2146cleanup:
2147 ext4_ext_drop_refs(npath);
2148 kfree(npath);
2149 return err;
2150}
2151
2152static int ext4_fill_fiemap_extents(struct inode *inode,
2153 ext4_lblk_t block, ext4_lblk_t num,
2154 struct fiemap_extent_info *fieinfo)
2155{
2156 struct ext4_ext_path *path = NULL;
2157 struct ext4_extent *ex;
2158 struct extent_status es;
2159 ext4_lblk_t next, next_del, start = 0, end = 0;
2160 ext4_lblk_t last = block + num;
2161 int exists, depth = 0, err = 0;
2162 unsigned int flags = 0;
2163 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2164
2165 while (block < last && block != EXT_MAX_BLOCKS) {
2166 num = last - block;
2167 /* find extent for this block */
2168 down_read(&EXT4_I(inode)->i_data_sem);
2169
2170 path = ext4_find_extent(inode, block, &path, 0);
2171 if (IS_ERR(path)) {
2172 up_read(&EXT4_I(inode)->i_data_sem);
2173 err = PTR_ERR(path);
2174 path = NULL;
2175 break;
2176 }
2177
2178 depth = ext_depth(inode);
2179 if (unlikely(path[depth].p_hdr == NULL)) {
2180 up_read(&EXT4_I(inode)->i_data_sem);
2181 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2182 err = -EFSCORRUPTED;
2183 break;
2184 }
2185 ex = path[depth].p_ext;
2186 next = ext4_ext_next_allocated_block(path);
2187
2188 flags = 0;
2189 exists = 0;
2190 if (!ex) {
2191 /* there is no extent yet, so try to allocate
2192 * all requested space */
2193 start = block;
2194 end = block + num;
2195 } else if (le32_to_cpu(ex->ee_block) > block) {
2196 /* need to allocate space before found extent */
2197 start = block;
2198 end = le32_to_cpu(ex->ee_block);
2199 if (block + num < end)
2200 end = block + num;
2201 } else if (block >= le32_to_cpu(ex->ee_block)
2202 + ext4_ext_get_actual_len(ex)) {
2203 /* need to allocate space after found extent */
2204 start = block;
2205 end = block + num;
2206 if (end >= next)
2207 end = next;
2208 } else if (block >= le32_to_cpu(ex->ee_block)) {
2209 /*
2210 * some part of requested space is covered
2211 * by found extent
2212 */
2213 start = block;
2214 end = le32_to_cpu(ex->ee_block)
2215 + ext4_ext_get_actual_len(ex);
2216 if (block + num < end)
2217 end = block + num;
2218 exists = 1;
2219 } else {
2220 BUG();
2221 }
2222 BUG_ON(end <= start);
2223
2224 if (!exists) {
2225 es.es_lblk = start;
2226 es.es_len = end - start;
2227 es.es_pblk = 0;
2228 } else {
2229 es.es_lblk = le32_to_cpu(ex->ee_block);
2230 es.es_len = ext4_ext_get_actual_len(ex);
2231 es.es_pblk = ext4_ext_pblock(ex);
2232 if (ext4_ext_is_unwritten(ex))
2233 flags |= FIEMAP_EXTENT_UNWRITTEN;
2234 }
2235
2236 /*
2237 * Find delayed extent and update es accordingly. We call
2238 * it even in !exists case to find out whether es is the
2239 * last existing extent or not.
2240 */
2241 next_del = ext4_find_delayed_extent(inode, &es);
2242 if (!exists && next_del) {
2243 exists = 1;
2244 flags |= (FIEMAP_EXTENT_DELALLOC |
2245 FIEMAP_EXTENT_UNKNOWN);
2246 }
2247 up_read(&EXT4_I(inode)->i_data_sem);
2248
2249 if (unlikely(es.es_len == 0)) {
2250 EXT4_ERROR_INODE(inode, "es.es_len == 0");
2251 err = -EFSCORRUPTED;
2252 break;
2253 }
2254
2255 /*
2256 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2257 * we need to check next == EXT_MAX_BLOCKS because it is
2258 * possible that an extent is with unwritten and delayed
2259 * status due to when an extent is delayed allocated and
2260 * is allocated by fallocate status tree will track both of
2261 * them in a extent.
2262 *
2263 * So we could return a unwritten and delayed extent, and
2264 * its block is equal to 'next'.
2265 */
2266 if (next == next_del && next == EXT_MAX_BLOCKS) {
2267 flags |= FIEMAP_EXTENT_LAST;
2268 if (unlikely(next_del != EXT_MAX_BLOCKS ||
2269 next != EXT_MAX_BLOCKS)) {
2270 EXT4_ERROR_INODE(inode,
2271 "next extent == %u, next "
2272 "delalloc extent = %u",
2273 next, next_del);
2274 err = -EFSCORRUPTED;
2275 break;
2276 }
2277 }
2278
2279 if (exists) {
2280 err = fiemap_fill_next_extent(fieinfo,
2281 (__u64)es.es_lblk << blksize_bits,
2282 (__u64)es.es_pblk << blksize_bits,
2283 (__u64)es.es_len << blksize_bits,
2284 flags);
2285 if (err < 0)
2286 break;
2287 if (err == 1) {
2288 err = 0;
2289 break;
2290 }
2291 }
2292
2293 block = es.es_lblk + es.es_len;
2294 }
2295
2296 ext4_ext_drop_refs(path);
2297 kfree(path);
2298 return err;
2299}
2300
2301/*
2302 * ext4_ext_determine_hole - determine hole around given block
2303 * @inode: inode we lookup in
2304 * @path: path in extent tree to @lblk
2305 * @lblk: pointer to logical block around which we want to determine hole
2306 *
2307 * Determine hole length (and start if easily possible) around given logical
2308 * block. We don't try too hard to find the beginning of the hole but @path
2309 * actually points to extent before @lblk, we provide it.
2310 *
2311 * The function returns the length of a hole starting at @lblk. We update @lblk
2312 * to the beginning of the hole if we managed to find it.
2313 */
2314static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2315 struct ext4_ext_path *path,
2316 ext4_lblk_t *lblk)
2317{
2318 int depth = ext_depth(inode);
2319 struct ext4_extent *ex;
2320 ext4_lblk_t len;
2321
2322 ex = path[depth].p_ext;
2323 if (ex == NULL) {
2324 /* there is no extent yet, so gap is [0;-] */
2325 *lblk = 0;
2326 len = EXT_MAX_BLOCKS;
2327 } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2328 len = le32_to_cpu(ex->ee_block) - *lblk;
2329 } else if (*lblk >= le32_to_cpu(ex->ee_block)
2330 + ext4_ext_get_actual_len(ex)) {
2331 ext4_lblk_t next;
2332
2333 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2334 next = ext4_ext_next_allocated_block(path);
2335 BUG_ON(next == *lblk);
2336 len = next - *lblk;
2337 } else {
2338 BUG();
2339 }
2340 return len;
2341}
2342
2343/*
2344 * ext4_ext_put_gap_in_cache:
2345 * calculate boundaries of the gap that the requested block fits into
2346 * and cache this gap
2347 */
2348static void
2349ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2350 ext4_lblk_t hole_len)
2351{
2352 struct extent_status es;
2353
2354 ext4_es_find_delayed_extent_range(inode, hole_start,
2355 hole_start + hole_len - 1, &es);
2356 if (es.es_len) {
2357 /* There's delayed extent containing lblock? */
2358 if (es.es_lblk <= hole_start)
2359 return;
2360 hole_len = min(es.es_lblk - hole_start, hole_len);
2361 }
2362 ext_debug(" -> %u:%u\n", hole_start, hole_len);
2363 ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2364 EXTENT_STATUS_HOLE);
2365}
2366
2367/*
2368 * ext4_ext_rm_idx:
2369 * removes index from the index block.
2370 */
2371static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2372 struct ext4_ext_path *path, int depth)
2373{
2374 int err;
2375 ext4_fsblk_t leaf;
2376
2377 /* free index block */
2378 depth--;
2379 path = path + depth;
2380 leaf = ext4_idx_pblock(path->p_idx);
2381 if (unlikely(path->p_hdr->eh_entries == 0)) {
2382 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2383 return -EFSCORRUPTED;
2384 }
2385 err = ext4_ext_get_access(handle, inode, path);
2386 if (err)
2387 return err;
2388
2389 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2390 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2391 len *= sizeof(struct ext4_extent_idx);
2392 memmove(path->p_idx, path->p_idx + 1, len);
2393 }
2394
2395 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2396 err = ext4_ext_dirty(handle, inode, path);
2397 if (err)
2398 return err;
2399 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2400 trace_ext4_ext_rm_idx(inode, leaf);
2401
2402 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2403 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2404
2405 while (--depth >= 0) {
2406 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2407 break;
2408 path--;
2409 err = ext4_ext_get_access(handle, inode, path);
2410 if (err)
2411 break;
2412 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2413 err = ext4_ext_dirty(handle, inode, path);
2414 if (err)
2415 break;
2416 }
2417 return err;
2418}
2419
2420/*
2421 * ext4_ext_calc_credits_for_single_extent:
2422 * This routine returns max. credits that needed to insert an extent
2423 * to the extent tree.
2424 * When pass the actual path, the caller should calculate credits
2425 * under i_data_sem.
2426 */
2427int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2428 struct ext4_ext_path *path)
2429{
2430 if (path) {
2431 int depth = ext_depth(inode);
2432 int ret = 0;
2433
2434 /* probably there is space in leaf? */
2435 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2436 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2437
2438 /*
2439 * There are some space in the leaf tree, no
2440 * need to account for leaf block credit
2441 *
2442 * bitmaps and block group descriptor blocks
2443 * and other metadata blocks still need to be
2444 * accounted.
2445 */
2446 /* 1 bitmap, 1 block group descriptor */
2447 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2448 return ret;
2449 }
2450 }
2451
2452 return ext4_chunk_trans_blocks(inode, nrblocks);
2453}
2454
2455/*
2456 * How many index/leaf blocks need to change/allocate to add @extents extents?
2457 *
2458 * If we add a single extent, then in the worse case, each tree level
2459 * index/leaf need to be changed in case of the tree split.
2460 *
2461 * If more extents are inserted, they could cause the whole tree split more
2462 * than once, but this is really rare.
2463 */
2464int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2465{
2466 int index;
2467 int depth;
2468
2469 /* If we are converting the inline data, only one is needed here. */
2470 if (ext4_has_inline_data(inode))
2471 return 1;
2472
2473 depth = ext_depth(inode);
2474
2475 if (extents <= 1)
2476 index = depth * 2;
2477 else
2478 index = depth * 3;
2479
2480 return index;
2481}
2482
2483static inline int get_default_free_blocks_flags(struct inode *inode)
2484{
2485 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2486 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2487 else if (ext4_should_journal_data(inode))
2488 return EXT4_FREE_BLOCKS_FORGET;
2489 return 0;
2490}
2491
2492static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2493 struct ext4_extent *ex,
2494 long long *partial_cluster,
2495 ext4_lblk_t from, ext4_lblk_t to)
2496{
2497 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2498 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2499 ext4_fsblk_t pblk;
2500 int flags = get_default_free_blocks_flags(inode);
2501
2502 /*
2503 * For bigalloc file systems, we never free a partial cluster
2504 * at the beginning of the extent. Instead, we make a note
2505 * that we tried freeing the cluster, and check to see if we
2506 * need to free it on a subsequent call to ext4_remove_blocks,
2507 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2508 */
2509 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2510
2511 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2512 /*
2513 * If we have a partial cluster, and it's different from the
2514 * cluster of the last block, we need to explicitly free the
2515 * partial cluster here.
2516 */
2517 pblk = ext4_ext_pblock(ex) + ee_len - 1;
2518 if (*partial_cluster > 0 &&
2519 *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2520 ext4_free_blocks(handle, inode, NULL,
2521 EXT4_C2B(sbi, *partial_cluster),
2522 sbi->s_cluster_ratio, flags);
2523 *partial_cluster = 0;
2524 }
2525
2526#ifdef EXTENTS_STATS
2527 {
2528 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2529 spin_lock(&sbi->s_ext_stats_lock);
2530 sbi->s_ext_blocks += ee_len;
2531 sbi->s_ext_extents++;
2532 if (ee_len < sbi->s_ext_min)
2533 sbi->s_ext_min = ee_len;
2534 if (ee_len > sbi->s_ext_max)
2535 sbi->s_ext_max = ee_len;
2536 if (ext_depth(inode) > sbi->s_depth_max)
2537 sbi->s_depth_max = ext_depth(inode);
2538 spin_unlock(&sbi->s_ext_stats_lock);
2539 }
2540#endif
2541 if (from >= le32_to_cpu(ex->ee_block)
2542 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2543 /* tail removal */
2544 ext4_lblk_t num;
2545 long long first_cluster;
2546
2547 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2548 pblk = ext4_ext_pblock(ex) + ee_len - num;
2549 /*
2550 * Usually we want to free partial cluster at the end of the
2551 * extent, except for the situation when the cluster is still
2552 * used by any other extent (partial_cluster is negative).
2553 */
2554 if (*partial_cluster < 0 &&
2555 *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2556 flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2557
2558 ext_debug("free last %u blocks starting %llu partial %lld\n",
2559 num, pblk, *partial_cluster);
2560 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2561 /*
2562 * If the block range to be freed didn't start at the
2563 * beginning of a cluster, and we removed the entire
2564 * extent and the cluster is not used by any other extent,
2565 * save the partial cluster here, since we might need to
2566 * delete if we determine that the truncate or punch hole
2567 * operation has removed all of the blocks in the cluster.
2568 * If that cluster is used by another extent, preserve its
2569 * negative value so it isn't freed later on.
2570 *
2571 * If the whole extent wasn't freed, we've reached the
2572 * start of the truncated/punched region and have finished
2573 * removing blocks. If there's a partial cluster here it's
2574 * shared with the remainder of the extent and is no longer
2575 * a candidate for removal.
2576 */
2577 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2578 first_cluster = (long long) EXT4_B2C(sbi, pblk);
2579 if (first_cluster != -*partial_cluster)
2580 *partial_cluster = first_cluster;
2581 } else {
2582 *partial_cluster = 0;
2583 }
2584 } else
2585 ext4_error(sbi->s_sb, "strange request: removal(2) "
2586 "%u-%u from %u:%u\n",
2587 from, to, le32_to_cpu(ex->ee_block), ee_len);
2588 return 0;
2589}
2590
2591
2592/*
2593 * ext4_ext_rm_leaf() Removes the extents associated with the
2594 * blocks appearing between "start" and "end". Both "start"
2595 * and "end" must appear in the same extent or EIO is returned.
2596 *
2597 * @handle: The journal handle
2598 * @inode: The files inode
2599 * @path: The path to the leaf
2600 * @partial_cluster: The cluster which we'll have to free if all extents
2601 * has been released from it. However, if this value is
2602 * negative, it's a cluster just to the right of the
2603 * punched region and it must not be freed.
2604 * @start: The first block to remove
2605 * @end: The last block to remove
2606 */
2607static int
2608ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2609 struct ext4_ext_path *path,
2610 long long *partial_cluster,
2611 ext4_lblk_t start, ext4_lblk_t end)
2612{
2613 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2614 int err = 0, correct_index = 0;
2615 int depth = ext_depth(inode), credits;
2616 struct ext4_extent_header *eh;
2617 ext4_lblk_t a, b;
2618 unsigned num;
2619 ext4_lblk_t ex_ee_block;
2620 unsigned short ex_ee_len;
2621 unsigned unwritten = 0;
2622 struct ext4_extent *ex;
2623 ext4_fsblk_t pblk;
2624
2625 /* the header must be checked already in ext4_ext_remove_space() */
2626 ext_debug("truncate since %u in leaf to %u\n", start, end);
2627 if (!path[depth].p_hdr)
2628 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2629 eh = path[depth].p_hdr;
2630 if (unlikely(path[depth].p_hdr == NULL)) {
2631 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2632 return -EFSCORRUPTED;
2633 }
2634 /* find where to start removing */
2635 ex = path[depth].p_ext;
2636 if (!ex)
2637 ex = EXT_LAST_EXTENT(eh);
2638
2639 ex_ee_block = le32_to_cpu(ex->ee_block);
2640 ex_ee_len = ext4_ext_get_actual_len(ex);
2641
2642 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2643
2644 while (ex >= EXT_FIRST_EXTENT(eh) &&
2645 ex_ee_block + ex_ee_len > start) {
2646
2647 if (ext4_ext_is_unwritten(ex))
2648 unwritten = 1;
2649 else
2650 unwritten = 0;
2651
2652 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2653 unwritten, ex_ee_len);
2654 path[depth].p_ext = ex;
2655
2656 a = ex_ee_block > start ? ex_ee_block : start;
2657 b = ex_ee_block+ex_ee_len - 1 < end ?
2658 ex_ee_block+ex_ee_len - 1 : end;
2659
2660 ext_debug(" border %u:%u\n", a, b);
2661
2662 /* If this extent is beyond the end of the hole, skip it */
2663 if (end < ex_ee_block) {
2664 /*
2665 * We're going to skip this extent and move to another,
2666 * so note that its first cluster is in use to avoid
2667 * freeing it when removing blocks. Eventually, the
2668 * right edge of the truncated/punched region will
2669 * be just to the left.
2670 */
2671 if (sbi->s_cluster_ratio > 1) {
2672 pblk = ext4_ext_pblock(ex);
2673 *partial_cluster =
2674 -(long long) EXT4_B2C(sbi, pblk);
2675 }
2676 ex--;
2677 ex_ee_block = le32_to_cpu(ex->ee_block);
2678 ex_ee_len = ext4_ext_get_actual_len(ex);
2679 continue;
2680 } else if (b != ex_ee_block + ex_ee_len - 1) {
2681 EXT4_ERROR_INODE(inode,
2682 "can not handle truncate %u:%u "
2683 "on extent %u:%u",
2684 start, end, ex_ee_block,
2685 ex_ee_block + ex_ee_len - 1);
2686 err = -EFSCORRUPTED;
2687 goto out;
2688 } else if (a != ex_ee_block) {
2689 /* remove tail of the extent */
2690 num = a - ex_ee_block;
2691 } else {
2692 /* remove whole extent: excellent! */
2693 num = 0;
2694 }
2695 /*
2696 * 3 for leaf, sb, and inode plus 2 (bmap and group
2697 * descriptor) for each block group; assume two block
2698 * groups plus ex_ee_len/blocks_per_block_group for
2699 * the worst case
2700 */
2701 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2702 if (ex == EXT_FIRST_EXTENT(eh)) {
2703 correct_index = 1;
2704 credits += (ext_depth(inode)) + 1;
2705 }
2706 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2707
2708 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2709 if (err)
2710 goto out;
2711
2712 err = ext4_ext_get_access(handle, inode, path + depth);
2713 if (err)
2714 goto out;
2715
2716 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2717 a, b);
2718 if (err)
2719 goto out;
2720
2721 if (num == 0)
2722 /* this extent is removed; mark slot entirely unused */
2723 ext4_ext_store_pblock(ex, 0);
2724
2725 ex->ee_len = cpu_to_le16(num);
2726 /*
2727 * Do not mark unwritten if all the blocks in the
2728 * extent have been removed.
2729 */
2730 if (unwritten && num)
2731 ext4_ext_mark_unwritten(ex);
2732 /*
2733 * If the extent was completely released,
2734 * we need to remove it from the leaf
2735 */
2736 if (num == 0) {
2737 if (end != EXT_MAX_BLOCKS - 1) {
2738 /*
2739 * For hole punching, we need to scoot all the
2740 * extents up when an extent is removed so that
2741 * we dont have blank extents in the middle
2742 */
2743 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2744 sizeof(struct ext4_extent));
2745
2746 /* Now get rid of the one at the end */
2747 memset(EXT_LAST_EXTENT(eh), 0,
2748 sizeof(struct ext4_extent));
2749 }
2750 le16_add_cpu(&eh->eh_entries, -1);
2751 }
2752
2753 err = ext4_ext_dirty(handle, inode, path + depth);
2754 if (err)
2755 goto out;
2756
2757 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2758 ext4_ext_pblock(ex));
2759 ex--;
2760 ex_ee_block = le32_to_cpu(ex->ee_block);
2761 ex_ee_len = ext4_ext_get_actual_len(ex);
2762 }
2763
2764 if (correct_index && eh->eh_entries)
2765 err = ext4_ext_correct_indexes(handle, inode, path);
2766
2767 /*
2768 * If there's a partial cluster and at least one extent remains in
2769 * the leaf, free the partial cluster if it isn't shared with the
2770 * current extent. If it is shared with the current extent
2771 * we zero partial_cluster because we've reached the start of the
2772 * truncated/punched region and we're done removing blocks.
2773 */
2774 if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2775 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2776 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2777 ext4_free_blocks(handle, inode, NULL,
2778 EXT4_C2B(sbi, *partial_cluster),
2779 sbi->s_cluster_ratio,
2780 get_default_free_blocks_flags(inode));
2781 }
2782 *partial_cluster = 0;
2783 }
2784
2785 /* if this leaf is free, then we should
2786 * remove it from index block above */
2787 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2788 err = ext4_ext_rm_idx(handle, inode, path, depth);
2789
2790out:
2791 return err;
2792}
2793
2794/*
2795 * ext4_ext_more_to_rm:
2796 * returns 1 if current index has to be freed (even partial)
2797 */
2798static int
2799ext4_ext_more_to_rm(struct ext4_ext_path *path)
2800{
2801 BUG_ON(path->p_idx == NULL);
2802
2803 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2804 return 0;
2805
2806 /*
2807 * if truncate on deeper level happened, it wasn't partial,
2808 * so we have to consider current index for truncation
2809 */
2810 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2811 return 0;
2812 return 1;
2813}
2814
2815int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2816 ext4_lblk_t end)
2817{
2818 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2819 int depth = ext_depth(inode);
2820 struct ext4_ext_path *path = NULL;
2821 long long partial_cluster = 0;
2822 handle_t *handle;
2823 int i = 0, err = 0;
2824
2825 ext_debug("truncate since %u to %u\n", start, end);
2826
2827 /* probably first extent we're gonna free will be last in block */
2828 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2829 if (IS_ERR(handle))
2830 return PTR_ERR(handle);
2831
2832again:
2833 trace_ext4_ext_remove_space(inode, start, end, depth);
2834
2835 /*
2836 * Check if we are removing extents inside the extent tree. If that
2837 * is the case, we are going to punch a hole inside the extent tree
2838 * so we have to check whether we need to split the extent covering
2839 * the last block to remove so we can easily remove the part of it
2840 * in ext4_ext_rm_leaf().
2841 */
2842 if (end < EXT_MAX_BLOCKS - 1) {
2843 struct ext4_extent *ex;
2844 ext4_lblk_t ee_block, ex_end, lblk;
2845 ext4_fsblk_t pblk;
2846
2847 /* find extent for or closest extent to this block */
2848 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2849 if (IS_ERR(path)) {
2850 ext4_journal_stop(handle);
2851 return PTR_ERR(path);
2852 }
2853 depth = ext_depth(inode);
2854 /* Leaf not may not exist only if inode has no blocks at all */
2855 ex = path[depth].p_ext;
2856 if (!ex) {
2857 if (depth) {
2858 EXT4_ERROR_INODE(inode,
2859 "path[%d].p_hdr == NULL",
2860 depth);
2861 err = -EFSCORRUPTED;
2862 }
2863 goto out;
2864 }
2865
2866 ee_block = le32_to_cpu(ex->ee_block);
2867 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2868
2869 /*
2870 * See if the last block is inside the extent, if so split
2871 * the extent at 'end' block so we can easily remove the
2872 * tail of the first part of the split extent in
2873 * ext4_ext_rm_leaf().
2874 */
2875 if (end >= ee_block && end < ex_end) {
2876
2877 /*
2878 * If we're going to split the extent, note that
2879 * the cluster containing the block after 'end' is
2880 * in use to avoid freeing it when removing blocks.
2881 */
2882 if (sbi->s_cluster_ratio > 1) {
2883 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2884 partial_cluster =
2885 -(long long) EXT4_B2C(sbi, pblk);
2886 }
2887
2888 /*
2889 * Split the extent in two so that 'end' is the last
2890 * block in the first new extent. Also we should not
2891 * fail removing space due to ENOSPC so try to use
2892 * reserved block if that happens.
2893 */
2894 err = ext4_force_split_extent_at(handle, inode, &path,
2895 end + 1, 1);
2896 if (err < 0)
2897 goto out;
2898
2899 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2900 /*
2901 * If there's an extent to the right its first cluster
2902 * contains the immediate right boundary of the
2903 * truncated/punched region. Set partial_cluster to
2904 * its negative value so it won't be freed if shared
2905 * with the current extent. The end < ee_block case
2906 * is handled in ext4_ext_rm_leaf().
2907 */
2908 lblk = ex_end + 1;
2909 err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2910 &ex);
2911 if (err)
2912 goto out;
2913 if (pblk)
2914 partial_cluster =
2915 -(long long) EXT4_B2C(sbi, pblk);
2916 }
2917 }
2918 /*
2919 * We start scanning from right side, freeing all the blocks
2920 * after i_size and walking into the tree depth-wise.
2921 */
2922 depth = ext_depth(inode);
2923 if (path) {
2924 int k = i = depth;
2925 while (--k > 0)
2926 path[k].p_block =
2927 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2928 } else {
2929 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2930 GFP_NOFS);
2931 if (path == NULL) {
2932 ext4_journal_stop(handle);
2933 return -ENOMEM;
2934 }
2935 path[0].p_maxdepth = path[0].p_depth = depth;
2936 path[0].p_hdr = ext_inode_hdr(inode);
2937 i = 0;
2938
2939 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2940 err = -EFSCORRUPTED;
2941 goto out;
2942 }
2943 }
2944 err = 0;
2945
2946 while (i >= 0 && err == 0) {
2947 if (i == depth) {
2948 /* this is leaf block */
2949 err = ext4_ext_rm_leaf(handle, inode, path,
2950 &partial_cluster, start,
2951 end);
2952 /* root level has p_bh == NULL, brelse() eats this */
2953 brelse(path[i].p_bh);
2954 path[i].p_bh = NULL;
2955 i--;
2956 continue;
2957 }
2958
2959 /* this is index block */
2960 if (!path[i].p_hdr) {
2961 ext_debug("initialize header\n");
2962 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2963 }
2964
2965 if (!path[i].p_idx) {
2966 /* this level hasn't been touched yet */
2967 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2968 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2969 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2970 path[i].p_hdr,
2971 le16_to_cpu(path[i].p_hdr->eh_entries));
2972 } else {
2973 /* we were already here, see at next index */
2974 path[i].p_idx--;
2975 }
2976
2977 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2978 i, EXT_FIRST_INDEX(path[i].p_hdr),
2979 path[i].p_idx);
2980 if (ext4_ext_more_to_rm(path + i)) {
2981 struct buffer_head *bh;
2982 /* go to the next level */
2983 ext_debug("move to level %d (block %llu)\n",
2984 i + 1, ext4_idx_pblock(path[i].p_idx));
2985 memset(path + i + 1, 0, sizeof(*path));
2986 bh = read_extent_tree_block(inode,
2987 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2988 EXT4_EX_NOCACHE);
2989 if (IS_ERR(bh)) {
2990 /* should we reset i_size? */
2991 err = PTR_ERR(bh);
2992 break;
2993 }
2994 /* Yield here to deal with large extent trees.
2995 * Should be a no-op if we did IO above. */
2996 cond_resched();
2997 if (WARN_ON(i + 1 > depth)) {
2998 err = -EFSCORRUPTED;
2999 break;
3000 }
3001 path[i + 1].p_bh = bh;
3002
3003 /* save actual number of indexes since this
3004 * number is changed at the next iteration */
3005 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3006 i++;
3007 } else {
3008 /* we finished processing this index, go up */
3009 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3010 /* index is empty, remove it;
3011 * handle must be already prepared by the
3012 * truncatei_leaf() */
3013 err = ext4_ext_rm_idx(handle, inode, path, i);
3014 }
3015 /* root level has p_bh == NULL, brelse() eats this */
3016 brelse(path[i].p_bh);
3017 path[i].p_bh = NULL;
3018 i--;
3019 ext_debug("return to level %d\n", i);
3020 }
3021 }
3022
3023 trace_ext4_ext_remove_space_done(inode, start, end, depth,
3024 partial_cluster, path->p_hdr->eh_entries);
3025
3026 /*
3027 * If we still have something in the partial cluster and we have removed
3028 * even the first extent, then we should free the blocks in the partial
3029 * cluster as well. (This code will only run when there are no leaves
3030 * to the immediate left of the truncated/punched region.)
3031 */
3032 if (partial_cluster > 0 && err == 0) {
3033 /* don't zero partial_cluster since it's not used afterwards */
3034 ext4_free_blocks(handle, inode, NULL,
3035 EXT4_C2B(sbi, partial_cluster),
3036 sbi->s_cluster_ratio,
3037 get_default_free_blocks_flags(inode));
3038 }
3039
3040 /* TODO: flexible tree reduction should be here */
3041 if (path->p_hdr->eh_entries == 0) {
3042 /*
3043 * truncate to zero freed all the tree,
3044 * so we need to correct eh_depth
3045 */
3046 err = ext4_ext_get_access(handle, inode, path);
3047 if (err == 0) {
3048 ext_inode_hdr(inode)->eh_depth = 0;
3049 ext_inode_hdr(inode)->eh_max =
3050 cpu_to_le16(ext4_ext_space_root(inode, 0));
3051 err = ext4_ext_dirty(handle, inode, path);
3052 }
3053 }
3054out:
3055 ext4_ext_drop_refs(path);
3056 kfree(path);
3057 path = NULL;
3058 if (err == -EAGAIN)
3059 goto again;
3060 ext4_journal_stop(handle);
3061
3062 return err;
3063}
3064
3065/*
3066 * called at mount time
3067 */
3068void ext4_ext_init(struct super_block *sb)
3069{
3070 /*
3071 * possible initialization would be here
3072 */
3073
3074 if (ext4_has_feature_extents(sb)) {
3075#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3076 printk(KERN_INFO "EXT4-fs: file extents enabled"
3077#ifdef AGGRESSIVE_TEST
3078 ", aggressive tests"
3079#endif
3080#ifdef CHECK_BINSEARCH
3081 ", check binsearch"
3082#endif
3083#ifdef EXTENTS_STATS
3084 ", stats"
3085#endif
3086 "\n");
3087#endif
3088#ifdef EXTENTS_STATS
3089 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3090 EXT4_SB(sb)->s_ext_min = 1 << 30;
3091 EXT4_SB(sb)->s_ext_max = 0;
3092#endif
3093 }
3094}
3095
3096/*
3097 * called at umount time
3098 */
3099void ext4_ext_release(struct super_block *sb)
3100{
3101 if (!ext4_has_feature_extents(sb))
3102 return;
3103
3104#ifdef EXTENTS_STATS
3105 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3106 struct ext4_sb_info *sbi = EXT4_SB(sb);
3107 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3108 sbi->s_ext_blocks, sbi->s_ext_extents,
3109 sbi->s_ext_blocks / sbi->s_ext_extents);
3110 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3111 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3112 }
3113#endif
3114}
3115
3116static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3117{
3118 ext4_lblk_t ee_block;
3119 ext4_fsblk_t ee_pblock;
3120 unsigned int ee_len;
3121
3122 ee_block = le32_to_cpu(ex->ee_block);
3123 ee_len = ext4_ext_get_actual_len(ex);
3124 ee_pblock = ext4_ext_pblock(ex);
3125
3126 if (ee_len == 0)
3127 return 0;
3128
3129 return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3130 EXTENT_STATUS_WRITTEN);
3131}
3132
3133/* FIXME!! we need to try to merge to left or right after zero-out */
3134static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3135{
3136 ext4_fsblk_t ee_pblock;
3137 unsigned int ee_len;
3138
3139 ee_len = ext4_ext_get_actual_len(ex);
3140 ee_pblock = ext4_ext_pblock(ex);
3141 return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3142 ee_len);
3143}
3144
3145/*
3146 * ext4_split_extent_at() splits an extent at given block.
3147 *
3148 * @handle: the journal handle
3149 * @inode: the file inode
3150 * @path: the path to the extent
3151 * @split: the logical block where the extent is splitted.
3152 * @split_flags: indicates if the extent could be zeroout if split fails, and
3153 * the states(init or unwritten) of new extents.
3154 * @flags: flags used to insert new extent to extent tree.
3155 *
3156 *
3157 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3158 * of which are deterimined by split_flag.
3159 *
3160 * There are two cases:
3161 * a> the extent are splitted into two extent.
3162 * b> split is not needed, and just mark the extent.
3163 *
3164 * return 0 on success.
3165 */
3166static int ext4_split_extent_at(handle_t *handle,
3167 struct inode *inode,
3168 struct ext4_ext_path **ppath,
3169 ext4_lblk_t split,
3170 int split_flag,
3171 int flags)
3172{
3173 struct ext4_ext_path *path = *ppath;
3174 ext4_fsblk_t newblock;
3175 ext4_lblk_t ee_block;
3176 struct ext4_extent *ex, newex, orig_ex, zero_ex;
3177 struct ext4_extent *ex2 = NULL;
3178 unsigned int ee_len, depth;
3179 int err = 0;
3180
3181 BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3182 (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3183
3184 ext_debug("ext4_split_extents_at: inode %lu, logical"
3185 "block %llu\n", inode->i_ino, (unsigned long long)split);
3186
3187 ext4_ext_show_leaf(inode, path);
3188
3189 depth = ext_depth(inode);
3190 ex = path[depth].p_ext;
3191 ee_block = le32_to_cpu(ex->ee_block);
3192 ee_len = ext4_ext_get_actual_len(ex);
3193 newblock = split - ee_block + ext4_ext_pblock(ex);
3194
3195 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3196 BUG_ON(!ext4_ext_is_unwritten(ex) &&
3197 split_flag & (EXT4_EXT_MAY_ZEROOUT |
3198 EXT4_EXT_MARK_UNWRIT1 |
3199 EXT4_EXT_MARK_UNWRIT2));
3200
3201 err = ext4_ext_get_access(handle, inode, path + depth);
3202 if (err)
3203 goto out;
3204
3205 if (split == ee_block) {
3206 /*
3207 * case b: block @split is the block that the extent begins with
3208 * then we just change the state of the extent, and splitting
3209 * is not needed.
3210 */
3211 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3212 ext4_ext_mark_unwritten(ex);
3213 else
3214 ext4_ext_mark_initialized(ex);
3215
3216 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3217 ext4_ext_try_to_merge(handle, inode, path, ex);
3218
3219 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3220 goto out;
3221 }
3222
3223 /* case a */
3224 memcpy(&orig_ex, ex, sizeof(orig_ex));
3225 ex->ee_len = cpu_to_le16(split - ee_block);
3226 if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3227 ext4_ext_mark_unwritten(ex);
3228
3229 /*
3230 * path may lead to new leaf, not to original leaf any more
3231 * after ext4_ext_insert_extent() returns,
3232 */
3233 err = ext4_ext_dirty(handle, inode, path + depth);
3234 if (err)
3235 goto fix_extent_len;
3236
3237 ex2 = &newex;
3238 ex2->ee_block = cpu_to_le32(split);
3239 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
3240 ext4_ext_store_pblock(ex2, newblock);
3241 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3242 ext4_ext_mark_unwritten(ex2);
3243
3244 err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3245 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3246 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3247 if (split_flag & EXT4_EXT_DATA_VALID1) {
3248 err = ext4_ext_zeroout(inode, ex2);
3249 zero_ex.ee_block = ex2->ee_block;
3250 zero_ex.ee_len = cpu_to_le16(
3251 ext4_ext_get_actual_len(ex2));
3252 ext4_ext_store_pblock(&zero_ex,
3253 ext4_ext_pblock(ex2));
3254 } else {
3255 err = ext4_ext_zeroout(inode, ex);
3256 zero_ex.ee_block = ex->ee_block;
3257 zero_ex.ee_len = cpu_to_le16(
3258 ext4_ext_get_actual_len(ex));
3259 ext4_ext_store_pblock(&zero_ex,
3260 ext4_ext_pblock(ex));
3261 }
3262 } else {
3263 err = ext4_ext_zeroout(inode, &orig_ex);
3264 zero_ex.ee_block = orig_ex.ee_block;
3265 zero_ex.ee_len = cpu_to_le16(
3266 ext4_ext_get_actual_len(&orig_ex));
3267 ext4_ext_store_pblock(&zero_ex,
3268 ext4_ext_pblock(&orig_ex));
3269 }
3270
3271 if (err)
3272 goto fix_extent_len;
3273 /* update the extent length and mark as initialized */
3274 ex->ee_len = cpu_to_le16(ee_len);
3275 ext4_ext_try_to_merge(handle, inode, path, ex);
3276 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3277 if (err)
3278 goto fix_extent_len;
3279
3280 /* update extent status tree */
3281 err = ext4_zeroout_es(inode, &zero_ex);
3282
3283 goto out;
3284 } else if (err)
3285 goto fix_extent_len;
3286
3287out:
3288 ext4_ext_show_leaf(inode, path);
3289 return err;
3290
3291fix_extent_len:
3292 ex->ee_len = orig_ex.ee_len;
3293 ext4_ext_dirty(handle, inode, path + path->p_depth);
3294 return err;
3295}
3296
3297/*
3298 * ext4_split_extents() splits an extent and mark extent which is covered
3299 * by @map as split_flags indicates
3300 *
3301 * It may result in splitting the extent into multiple extents (up to three)
3302 * There are three possibilities:
3303 * a> There is no split required
3304 * b> Splits in two extents: Split is happening at either end of the extent
3305 * c> Splits in three extents: Somone is splitting in middle of the extent
3306 *
3307 */
3308static int ext4_split_extent(handle_t *handle,
3309 struct inode *inode,
3310 struct ext4_ext_path **ppath,
3311 struct ext4_map_blocks *map,
3312 int split_flag,
3313 int flags)
3314{
3315 struct ext4_ext_path *path = *ppath;
3316 ext4_lblk_t ee_block;
3317 struct ext4_extent *ex;
3318 unsigned int ee_len, depth;
3319 int err = 0;
3320 int unwritten;
3321 int split_flag1, flags1;
3322 int allocated = map->m_len;
3323
3324 depth = ext_depth(inode);
3325 ex = path[depth].p_ext;
3326 ee_block = le32_to_cpu(ex->ee_block);
3327 ee_len = ext4_ext_get_actual_len(ex);
3328 unwritten = ext4_ext_is_unwritten(ex);
3329
3330 if (map->m_lblk + map->m_len < ee_block + ee_len) {
3331 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3332 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3333 if (unwritten)
3334 split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3335 EXT4_EXT_MARK_UNWRIT2;
3336 if (split_flag & EXT4_EXT_DATA_VALID2)
3337 split_flag1 |= EXT4_EXT_DATA_VALID1;
3338 err = ext4_split_extent_at(handle, inode, ppath,
3339 map->m_lblk + map->m_len, split_flag1, flags1);
3340 if (err)
3341 goto out;
3342 } else {
3343 allocated = ee_len - (map->m_lblk - ee_block);
3344 }
3345 /*
3346 * Update path is required because previous ext4_split_extent_at() may
3347 * result in split of original leaf or extent zeroout.
3348 */
3349 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3350 if (IS_ERR(path))
3351 return PTR_ERR(path);
3352 depth = ext_depth(inode);
3353 ex = path[depth].p_ext;
3354 if (!ex) {
3355 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3356 (unsigned long) map->m_lblk);
3357 return -EFSCORRUPTED;
3358 }
3359 unwritten = ext4_ext_is_unwritten(ex);
3360 split_flag1 = 0;
3361
3362 if (map->m_lblk >= ee_block) {
3363 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3364 if (unwritten) {
3365 split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3366 split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3367 EXT4_EXT_MARK_UNWRIT2);
3368 }
3369 err = ext4_split_extent_at(handle, inode, ppath,
3370 map->m_lblk, split_flag1, flags);
3371 if (err)
3372 goto out;
3373 }
3374
3375 ext4_ext_show_leaf(inode, path);
3376out:
3377 return err ? err : allocated;
3378}
3379
3380/*
3381 * This function is called by ext4_ext_map_blocks() if someone tries to write
3382 * to an unwritten extent. It may result in splitting the unwritten
3383 * extent into multiple extents (up to three - one initialized and two
3384 * unwritten).
3385 * There are three possibilities:
3386 * a> There is no split required: Entire extent should be initialized
3387 * b> Splits in two extents: Write is happening at either end of the extent
3388 * c> Splits in three extents: Somone is writing in middle of the extent
3389 *
3390 * Pre-conditions:
3391 * - The extent pointed to by 'path' is unwritten.
3392 * - The extent pointed to by 'path' contains a superset
3393 * of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3394 *
3395 * Post-conditions on success:
3396 * - the returned value is the number of blocks beyond map->l_lblk
3397 * that are allocated and initialized.
3398 * It is guaranteed to be >= map->m_len.
3399 */
3400static int ext4_ext_convert_to_initialized(handle_t *handle,
3401 struct inode *inode,
3402 struct ext4_map_blocks *map,
3403 struct ext4_ext_path **ppath,
3404 int flags)
3405{
3406 struct ext4_ext_path *path = *ppath;
3407 struct ext4_sb_info *sbi;
3408 struct ext4_extent_header *eh;
3409 struct ext4_map_blocks split_map;
3410 struct ext4_extent zero_ex;
3411 struct ext4_extent *ex, *abut_ex;
3412 ext4_lblk_t ee_block, eof_block;
3413 unsigned int ee_len, depth, map_len = map->m_len;
3414 int allocated = 0, max_zeroout = 0;
3415 int err = 0;
3416 int split_flag = 0;
3417
3418 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3419 "block %llu, max_blocks %u\n", inode->i_ino,
3420 (unsigned long long)map->m_lblk, map_len);
3421
3422 sbi = EXT4_SB(inode->i_sb);
3423 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3424 inode->i_sb->s_blocksize_bits;
3425 if (eof_block < map->m_lblk + map_len)
3426 eof_block = map->m_lblk + map_len;
3427
3428 depth = ext_depth(inode);
3429 eh = path[depth].p_hdr;
3430 ex = path[depth].p_ext;
3431 ee_block = le32_to_cpu(ex->ee_block);
3432 ee_len = ext4_ext_get_actual_len(ex);
3433 zero_ex.ee_len = 0;
3434
3435 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3436
3437 /* Pre-conditions */
3438 BUG_ON(!ext4_ext_is_unwritten(ex));
3439 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3440
3441 /*
3442 * Attempt to transfer newly initialized blocks from the currently
3443 * unwritten extent to its neighbor. This is much cheaper
3444 * than an insertion followed by a merge as those involve costly
3445 * memmove() calls. Transferring to the left is the common case in
3446 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3447 * followed by append writes.
3448 *
3449 * Limitations of the current logic:
3450 * - L1: we do not deal with writes covering the whole extent.
3451 * This would require removing the extent if the transfer
3452 * is possible.
3453 * - L2: we only attempt to merge with an extent stored in the
3454 * same extent tree node.
3455 */
3456 if ((map->m_lblk == ee_block) &&
3457 /* See if we can merge left */
3458 (map_len < ee_len) && /*L1*/
3459 (ex > EXT_FIRST_EXTENT(eh))) { /*L2*/
3460 ext4_lblk_t prev_lblk;
3461 ext4_fsblk_t prev_pblk, ee_pblk;
3462 unsigned int prev_len;
3463
3464 abut_ex = ex - 1;
3465 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3466 prev_len = ext4_ext_get_actual_len(abut_ex);
3467 prev_pblk = ext4_ext_pblock(abut_ex);
3468 ee_pblk = ext4_ext_pblock(ex);
3469
3470 /*
3471 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3472 * upon those conditions:
3473 * - C1: abut_ex is initialized,
3474 * - C2: abut_ex is logically abutting ex,
3475 * - C3: abut_ex is physically abutting ex,
3476 * - C4: abut_ex can receive the additional blocks without
3477 * overflowing the (initialized) length limit.
3478 */
3479 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3480 ((prev_lblk + prev_len) == ee_block) && /*C2*/
3481 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/
3482 (prev_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3483 err = ext4_ext_get_access(handle, inode, path + depth);
3484 if (err)
3485 goto out;
3486
3487 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3488 map, ex, abut_ex);
3489
3490 /* Shift the start of ex by 'map_len' blocks */
3491 ex->ee_block = cpu_to_le32(ee_block + map_len);
3492 ext4_ext_store_pblock(ex, ee_pblk + map_len);
3493 ex->ee_len = cpu_to_le16(ee_len - map_len);
3494 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3495
3496 /* Extend abut_ex by 'map_len' blocks */
3497 abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3498
3499 /* Result: number of initialized blocks past m_lblk */
3500 allocated = map_len;
3501 }
3502 } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3503 (map_len < ee_len) && /*L1*/
3504 ex < EXT_LAST_EXTENT(eh)) { /*L2*/
3505 /* See if we can merge right */
3506 ext4_lblk_t next_lblk;
3507 ext4_fsblk_t next_pblk, ee_pblk;
3508 unsigned int next_len;
3509
3510 abut_ex = ex + 1;
3511 next_lblk = le32_to_cpu(abut_ex->ee_block);
3512 next_len = ext4_ext_get_actual_len(abut_ex);
3513 next_pblk = ext4_ext_pblock(abut_ex);
3514 ee_pblk = ext4_ext_pblock(ex);
3515
3516 /*
3517 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3518 * upon those conditions:
3519 * - C1: abut_ex is initialized,
3520 * - C2: abut_ex is logically abutting ex,
3521 * - C3: abut_ex is physically abutting ex,
3522 * - C4: abut_ex can receive the additional blocks without
3523 * overflowing the (initialized) length limit.
3524 */
3525 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3526 ((map->m_lblk + map_len) == next_lblk) && /*C2*/
3527 ((ee_pblk + ee_len) == next_pblk) && /*C3*/
3528 (next_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3529 err = ext4_ext_get_access(handle, inode, path + depth);
3530 if (err)
3531 goto out;
3532
3533 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3534 map, ex, abut_ex);
3535
3536 /* Shift the start of abut_ex by 'map_len' blocks */
3537 abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3538 ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3539 ex->ee_len = cpu_to_le16(ee_len - map_len);
3540 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3541
3542 /* Extend abut_ex by 'map_len' blocks */
3543 abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3544
3545 /* Result: number of initialized blocks past m_lblk */
3546 allocated = map_len;
3547 }
3548 }
3549 if (allocated) {
3550 /* Mark the block containing both extents as dirty */
3551 ext4_ext_dirty(handle, inode, path + depth);
3552
3553 /* Update path to point to the right extent */
3554 path[depth].p_ext = abut_ex;
3555 goto out;
3556 } else
3557 allocated = ee_len - (map->m_lblk - ee_block);
3558
3559 WARN_ON(map->m_lblk < ee_block);
3560 /*
3561 * It is safe to convert extent to initialized via explicit
3562 * zeroout only if extent is fully inside i_size or new_size.
3563 */
3564 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3565
3566 if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3567 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3568 (inode->i_sb->s_blocksize_bits - 10);
3569
3570 if (ext4_encrypted_inode(inode))
3571 max_zeroout = 0;
3572
3573 /* If extent is less than s_max_zeroout_kb, zeroout directly */
3574 if (max_zeroout && (ee_len <= max_zeroout)) {
3575 err = ext4_ext_zeroout(inode, ex);
3576 if (err)
3577 goto out;
3578 zero_ex.ee_block = ex->ee_block;
3579 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3580 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3581
3582 err = ext4_ext_get_access(handle, inode, path + depth);
3583 if (err)
3584 goto out;
3585 ext4_ext_mark_initialized(ex);
3586 ext4_ext_try_to_merge(handle, inode, path, ex);
3587 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3588 goto out;
3589 }
3590
3591 /*
3592 * four cases:
3593 * 1. split the extent into three extents.
3594 * 2. split the extent into two extents, zeroout the first half.
3595 * 3. split the extent into two extents, zeroout the second half.
3596 * 4. split the extent into two extents with out zeroout.
3597 */
3598 split_map.m_lblk = map->m_lblk;
3599 split_map.m_len = map->m_len;
3600
3601 if (max_zeroout && (allocated > map->m_len)) {
3602 if (allocated <= max_zeroout) {
3603 /* case 3 */
3604 zero_ex.ee_block =
3605 cpu_to_le32(map->m_lblk);
3606 zero_ex.ee_len = cpu_to_le16(allocated);
3607 ext4_ext_store_pblock(&zero_ex,
3608 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3609 err = ext4_ext_zeroout(inode, &zero_ex);
3610 if (err)
3611 goto out;
3612 split_map.m_lblk = map->m_lblk;
3613 split_map.m_len = allocated;
3614 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3615 /* case 2 */
3616 if (map->m_lblk != ee_block) {
3617 zero_ex.ee_block = ex->ee_block;
3618 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3619 ee_block);
3620 ext4_ext_store_pblock(&zero_ex,
3621 ext4_ext_pblock(ex));
3622 err = ext4_ext_zeroout(inode, &zero_ex);
3623 if (err)
3624 goto out;
3625 }
3626
3627 split_map.m_lblk = ee_block;
3628 split_map.m_len = map->m_lblk - ee_block + map->m_len;
3629 allocated = map->m_len;
3630 }
3631 }
3632
3633 err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3634 flags);
3635 if (err > 0)
3636 err = 0;
3637out:
3638 /* If we have gotten a failure, don't zero out status tree */
3639 if (!err)
3640 err = ext4_zeroout_es(inode, &zero_ex);
3641 return err ? err : allocated;
3642}
3643
3644/*
3645 * This function is called by ext4_ext_map_blocks() from
3646 * ext4_get_blocks_dio_write() when DIO to write
3647 * to an unwritten extent.
3648 *
3649 * Writing to an unwritten extent may result in splitting the unwritten
3650 * extent into multiple initialized/unwritten extents (up to three)
3651 * There are three possibilities:
3652 * a> There is no split required: Entire extent should be unwritten
3653 * b> Splits in two extents: Write is happening at either end of the extent
3654 * c> Splits in three extents: Somone is writing in middle of the extent
3655 *
3656 * This works the same way in the case of initialized -> unwritten conversion.
3657 *
3658 * One of more index blocks maybe needed if the extent tree grow after
3659 * the unwritten extent split. To prevent ENOSPC occur at the IO
3660 * complete, we need to split the unwritten extent before DIO submit
3661 * the IO. The unwritten extent called at this time will be split
3662 * into three unwritten extent(at most). After IO complete, the part
3663 * being filled will be convert to initialized by the end_io callback function
3664 * via ext4_convert_unwritten_extents().
3665 *
3666 * Returns the size of unwritten extent to be written on success.
3667 */
3668static int ext4_split_convert_extents(handle_t *handle,
3669 struct inode *inode,
3670 struct ext4_map_blocks *map,
3671 struct ext4_ext_path **ppath,
3672 int flags)
3673{
3674 struct ext4_ext_path *path = *ppath;
3675 ext4_lblk_t eof_block;
3676 ext4_lblk_t ee_block;
3677 struct ext4_extent *ex;
3678 unsigned int ee_len;
3679 int split_flag = 0, depth;
3680
3681 ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3682 __func__, inode->i_ino,
3683 (unsigned long long)map->m_lblk, map->m_len);
3684
3685 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3686 inode->i_sb->s_blocksize_bits;
3687 if (eof_block < map->m_lblk + map->m_len)
3688 eof_block = map->m_lblk + map->m_len;
3689 /*
3690 * It is safe to convert extent to initialized via explicit
3691 * zeroout only if extent is fully insde i_size or new_size.
3692 */
3693 depth = ext_depth(inode);
3694 ex = path[depth].p_ext;
3695 ee_block = le32_to_cpu(ex->ee_block);
3696 ee_len = ext4_ext_get_actual_len(ex);
3697
3698 /* Convert to unwritten */
3699 if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3700 split_flag |= EXT4_EXT_DATA_VALID1;
3701 /* Convert to initialized */
3702 } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3703 split_flag |= ee_block + ee_len <= eof_block ?
3704 EXT4_EXT_MAY_ZEROOUT : 0;
3705 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3706 }
3707 flags |= EXT4_GET_BLOCKS_PRE_IO;
3708 return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3709}
3710
3711static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3712 struct inode *inode,
3713 struct ext4_map_blocks *map,
3714 struct ext4_ext_path **ppath)
3715{
3716 struct ext4_ext_path *path = *ppath;
3717 struct ext4_extent *ex;
3718 ext4_lblk_t ee_block;
3719 unsigned int ee_len;
3720 int depth;
3721 int err = 0;
3722
3723 depth = ext_depth(inode);
3724 ex = path[depth].p_ext;
3725 ee_block = le32_to_cpu(ex->ee_block);
3726 ee_len = ext4_ext_get_actual_len(ex);
3727
3728 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3729 "block %llu, max_blocks %u\n", inode->i_ino,
3730 (unsigned long long)ee_block, ee_len);
3731
3732 /* If extent is larger than requested it is a clear sign that we still
3733 * have some extent state machine issues left. So extent_split is still
3734 * required.
3735 * TODO: Once all related issues will be fixed this situation should be
3736 * illegal.
3737 */
3738 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3739#ifdef EXT4_DEBUG
3740 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3741 " len %u; IO logical block %llu, len %u\n",
3742 inode->i_ino, (unsigned long long)ee_block, ee_len,
3743 (unsigned long long)map->m_lblk, map->m_len);
3744#endif
3745 err = ext4_split_convert_extents(handle, inode, map, ppath,
3746 EXT4_GET_BLOCKS_CONVERT);
3747 if (err < 0)
3748 return err;
3749 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3750 if (IS_ERR(path))
3751 return PTR_ERR(path);
3752 depth = ext_depth(inode);
3753 ex = path[depth].p_ext;
3754 }
3755
3756 err = ext4_ext_get_access(handle, inode, path + depth);
3757 if (err)
3758 goto out;
3759 /* first mark the extent as initialized */
3760 ext4_ext_mark_initialized(ex);
3761
3762 /* note: ext4_ext_correct_indexes() isn't needed here because
3763 * borders are not changed
3764 */
3765 ext4_ext_try_to_merge(handle, inode, path, ex);
3766
3767 /* Mark modified extent as dirty */
3768 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3769out:
3770 ext4_ext_show_leaf(inode, path);
3771 return err;
3772}
3773
3774static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3775 sector_t block, int count)
3776{
3777 int i;
3778 for (i = 0; i < count; i++)
3779 unmap_underlying_metadata(bdev, block + i);
3780}
3781
3782/*
3783 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3784 */
3785static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3786 ext4_lblk_t lblk,
3787 struct ext4_ext_path *path,
3788 unsigned int len)
3789{
3790 int i, depth;
3791 struct ext4_extent_header *eh;
3792 struct ext4_extent *last_ex;
3793
3794 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3795 return 0;
3796
3797 depth = ext_depth(inode);
3798 eh = path[depth].p_hdr;
3799
3800 /*
3801 * We're going to remove EOFBLOCKS_FL entirely in future so we
3802 * do not care for this case anymore. Simply remove the flag
3803 * if there are no extents.
3804 */
3805 if (unlikely(!eh->eh_entries))
3806 goto out;
3807 last_ex = EXT_LAST_EXTENT(eh);
3808 /*
3809 * We should clear the EOFBLOCKS_FL flag if we are writing the
3810 * last block in the last extent in the file. We test this by
3811 * first checking to see if the caller to
3812 * ext4_ext_get_blocks() was interested in the last block (or
3813 * a block beyond the last block) in the current extent. If
3814 * this turns out to be false, we can bail out from this
3815 * function immediately.
3816 */
3817 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3818 ext4_ext_get_actual_len(last_ex))
3819 return 0;
3820 /*
3821 * If the caller does appear to be planning to write at or
3822 * beyond the end of the current extent, we then test to see
3823 * if the current extent is the last extent in the file, by
3824 * checking to make sure it was reached via the rightmost node
3825 * at each level of the tree.
3826 */
3827 for (i = depth-1; i >= 0; i--)
3828 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3829 return 0;
3830out:
3831 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3832 return ext4_mark_inode_dirty(handle, inode);
3833}
3834
3835/**
3836 * ext4_find_delalloc_range: find delayed allocated block in the given range.
3837 *
3838 * Return 1 if there is a delalloc block in the range, otherwise 0.
3839 */
3840int ext4_find_delalloc_range(struct inode *inode,
3841 ext4_lblk_t lblk_start,
3842 ext4_lblk_t lblk_end)
3843{
3844 struct extent_status es;
3845
3846 ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3847 if (es.es_len == 0)
3848 return 0; /* there is no delay extent in this tree */
3849 else if (es.es_lblk <= lblk_start &&
3850 lblk_start < es.es_lblk + es.es_len)
3851 return 1;
3852 else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3853 return 1;
3854 else
3855 return 0;
3856}
3857
3858int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3859{
3860 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3861 ext4_lblk_t lblk_start, lblk_end;
3862 lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3863 lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3864
3865 return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3866}
3867
3868/**
3869 * Determines how many complete clusters (out of those specified by the 'map')
3870 * are under delalloc and were reserved quota for.
3871 * This function is called when we are writing out the blocks that were
3872 * originally written with their allocation delayed, but then the space was
3873 * allocated using fallocate() before the delayed allocation could be resolved.
3874 * The cases to look for are:
3875 * ('=' indicated delayed allocated blocks
3876 * '-' indicates non-delayed allocated blocks)
3877 * (a) partial clusters towards beginning and/or end outside of allocated range
3878 * are not delalloc'ed.
3879 * Ex:
3880 * |----c---=|====c====|====c====|===-c----|
3881 * |++++++ allocated ++++++|
3882 * ==> 4 complete clusters in above example
3883 *
3884 * (b) partial cluster (outside of allocated range) towards either end is
3885 * marked for delayed allocation. In this case, we will exclude that
3886 * cluster.
3887 * Ex:
3888 * |----====c========|========c========|
3889 * |++++++ allocated ++++++|
3890 * ==> 1 complete clusters in above example
3891 *
3892 * Ex:
3893 * |================c================|
3894 * |++++++ allocated ++++++|
3895 * ==> 0 complete clusters in above example
3896 *
3897 * The ext4_da_update_reserve_space will be called only if we
3898 * determine here that there were some "entire" clusters that span
3899 * this 'allocated' range.
3900 * In the non-bigalloc case, this function will just end up returning num_blks
3901 * without ever calling ext4_find_delalloc_range.
3902 */
3903static unsigned int
3904get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3905 unsigned int num_blks)
3906{
3907 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3908 ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3909 ext4_lblk_t lblk_from, lblk_to, c_offset;
3910 unsigned int allocated_clusters = 0;
3911
3912 alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3913 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3914
3915 /* max possible clusters for this allocation */
3916 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3917
3918 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3919
3920 /* Check towards left side */
3921 c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3922 if (c_offset) {
3923 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3924 lblk_to = lblk_from + c_offset - 1;
3925
3926 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3927 allocated_clusters--;
3928 }
3929
3930 /* Now check towards right. */
3931 c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3932 if (allocated_clusters && c_offset) {
3933 lblk_from = lblk_start + num_blks;
3934 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3935
3936 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3937 allocated_clusters--;
3938 }
3939
3940 return allocated_clusters;
3941}
3942
3943static int
3944convert_initialized_extent(handle_t *handle, struct inode *inode,
3945 struct ext4_map_blocks *map,
3946 struct ext4_ext_path **ppath,
3947 unsigned int allocated)
3948{
3949 struct ext4_ext_path *path = *ppath;
3950 struct ext4_extent *ex;
3951 ext4_lblk_t ee_block;
3952 unsigned int ee_len;
3953 int depth;
3954 int err = 0;
3955
3956 /*
3957 * Make sure that the extent is no bigger than we support with
3958 * unwritten extent
3959 */
3960 if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3961 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3962
3963 depth = ext_depth(inode);
3964 ex = path[depth].p_ext;
3965 ee_block = le32_to_cpu(ex->ee_block);
3966 ee_len = ext4_ext_get_actual_len(ex);
3967
3968 ext_debug("%s: inode %lu, logical"
3969 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3970 (unsigned long long)ee_block, ee_len);
3971
3972 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3973 err = ext4_split_convert_extents(handle, inode, map, ppath,
3974 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3975 if (err < 0)
3976 return err;
3977 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3978 if (IS_ERR(path))
3979 return PTR_ERR(path);
3980 depth = ext_depth(inode);
3981 ex = path[depth].p_ext;
3982 if (!ex) {
3983 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3984 (unsigned long) map->m_lblk);
3985 return -EFSCORRUPTED;
3986 }
3987 }
3988
3989 err = ext4_ext_get_access(handle, inode, path + depth);
3990 if (err)
3991 return err;
3992 /* first mark the extent as unwritten */
3993 ext4_ext_mark_unwritten(ex);
3994
3995 /* note: ext4_ext_correct_indexes() isn't needed here because
3996 * borders are not changed
3997 */
3998 ext4_ext_try_to_merge(handle, inode, path, ex);
3999
4000 /* Mark modified extent as dirty */
4001 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4002 if (err)
4003 return err;
4004 ext4_ext_show_leaf(inode, path);
4005
4006 ext4_update_inode_fsync_trans(handle, inode, 1);
4007 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4008 if (err)
4009 return err;
4010 map->m_flags |= EXT4_MAP_UNWRITTEN;
4011 if (allocated > map->m_len)
4012 allocated = map->m_len;
4013 map->m_len = allocated;
4014 return allocated;
4015}
4016
4017static int
4018ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4019 struct ext4_map_blocks *map,
4020 struct ext4_ext_path **ppath, int flags,
4021 unsigned int allocated, ext4_fsblk_t newblock)
4022{
4023 struct ext4_ext_path *path = *ppath;
4024 int ret = 0;
4025 int err = 0;
4026
4027 ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4028 "block %llu, max_blocks %u, flags %x, allocated %u\n",
4029 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4030 flags, allocated);
4031 ext4_ext_show_leaf(inode, path);
4032
4033 /*
4034 * When writing into unwritten space, we should not fail to
4035 * allocate metadata blocks for the new extent block if needed.
4036 */
4037 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4038
4039 trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4040 allocated, newblock);
4041
4042 /* get_block() before submit the IO, split the extent */
4043 if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4044 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4045 flags | EXT4_GET_BLOCKS_CONVERT);
4046 if (ret <= 0)
4047 goto out;
4048 map->m_flags |= EXT4_MAP_UNWRITTEN;
4049 goto out;
4050 }
4051 /* IO end_io complete, convert the filled extent to written */
4052 if (flags & EXT4_GET_BLOCKS_CONVERT) {
4053 if (flags & EXT4_GET_BLOCKS_ZERO) {
4054 if (allocated > map->m_len)
4055 allocated = map->m_len;
4056 err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4057 allocated);
4058 if (err < 0)
4059 goto out2;
4060 }
4061 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4062 ppath);
4063 if (ret >= 0) {
4064 ext4_update_inode_fsync_trans(handle, inode, 1);
4065 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4066 path, map->m_len);
4067 } else
4068 err = ret;
4069 map->m_flags |= EXT4_MAP_MAPPED;
4070 map->m_pblk = newblock;
4071 if (allocated > map->m_len)
4072 allocated = map->m_len;
4073 map->m_len = allocated;
4074 goto out2;
4075 }
4076 /* buffered IO case */
4077 /*
4078 * repeat fallocate creation request
4079 * we already have an unwritten extent
4080 */
4081 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4082 map->m_flags |= EXT4_MAP_UNWRITTEN;
4083 goto map_out;
4084 }
4085
4086 /* buffered READ or buffered write_begin() lookup */
4087 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4088 /*
4089 * We have blocks reserved already. We
4090 * return allocated blocks so that delalloc
4091 * won't do block reservation for us. But
4092 * the buffer head will be unmapped so that
4093 * a read from the block returns 0s.
4094 */
4095 map->m_flags |= EXT4_MAP_UNWRITTEN;
4096 goto out1;
4097 }
4098
4099 /* buffered write, writepage time, convert*/
4100 ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4101 if (ret >= 0)
4102 ext4_update_inode_fsync_trans(handle, inode, 1);
4103out:
4104 if (ret <= 0) {
4105 err = ret;
4106 goto out2;
4107 } else
4108 allocated = ret;
4109 map->m_flags |= EXT4_MAP_NEW;
4110 /*
4111 * if we allocated more blocks than requested
4112 * we need to make sure we unmap the extra block
4113 * allocated. The actual needed block will get
4114 * unmapped later when we find the buffer_head marked
4115 * new.
4116 */
4117 if (allocated > map->m_len) {
4118 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4119 newblock + map->m_len,
4120 allocated - map->m_len);
4121 allocated = map->m_len;
4122 }
4123 map->m_len = allocated;
4124
4125 /*
4126 * If we have done fallocate with the offset that is already
4127 * delayed allocated, we would have block reservation
4128 * and quota reservation done in the delayed write path.
4129 * But fallocate would have already updated quota and block
4130 * count for this offset. So cancel these reservation
4131 */
4132 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4133 unsigned int reserved_clusters;
4134 reserved_clusters = get_reserved_cluster_alloc(inode,
4135 map->m_lblk, map->m_len);
4136 if (reserved_clusters)
4137 ext4_da_update_reserve_space(inode,
4138 reserved_clusters,
4139 0);
4140 }
4141
4142map_out:
4143 map->m_flags |= EXT4_MAP_MAPPED;
4144 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4145 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4146 map->m_len);
4147 if (err < 0)
4148 goto out2;
4149 }
4150out1:
4151 if (allocated > map->m_len)
4152 allocated = map->m_len;
4153 ext4_ext_show_leaf(inode, path);
4154 map->m_pblk = newblock;
4155 map->m_len = allocated;
4156out2:
4157 return err ? err : allocated;
4158}
4159
4160/*
4161 * get_implied_cluster_alloc - check to see if the requested
4162 * allocation (in the map structure) overlaps with a cluster already
4163 * allocated in an extent.
4164 * @sb The filesystem superblock structure
4165 * @map The requested lblk->pblk mapping
4166 * @ex The extent structure which might contain an implied
4167 * cluster allocation
4168 *
4169 * This function is called by ext4_ext_map_blocks() after we failed to
4170 * find blocks that were already in the inode's extent tree. Hence,
4171 * we know that the beginning of the requested region cannot overlap
4172 * the extent from the inode's extent tree. There are three cases we
4173 * want to catch. The first is this case:
4174 *
4175 * |--- cluster # N--|
4176 * |--- extent ---| |---- requested region ---|
4177 * |==========|
4178 *
4179 * The second case that we need to test for is this one:
4180 *
4181 * |--------- cluster # N ----------------|
4182 * |--- requested region --| |------- extent ----|
4183 * |=======================|
4184 *
4185 * The third case is when the requested region lies between two extents
4186 * within the same cluster:
4187 * |------------- cluster # N-------------|
4188 * |----- ex -----| |---- ex_right ----|
4189 * |------ requested region ------|
4190 * |================|
4191 *
4192 * In each of the above cases, we need to set the map->m_pblk and
4193 * map->m_len so it corresponds to the return the extent labelled as
4194 * "|====|" from cluster #N, since it is already in use for data in
4195 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to
4196 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4197 * as a new "allocated" block region. Otherwise, we will return 0 and
4198 * ext4_ext_map_blocks() will then allocate one or more new clusters
4199 * by calling ext4_mb_new_blocks().
4200 */
4201static int get_implied_cluster_alloc(struct super_block *sb,
4202 struct ext4_map_blocks *map,
4203 struct ext4_extent *ex,
4204 struct ext4_ext_path *path)
4205{
4206 struct ext4_sb_info *sbi = EXT4_SB(sb);
4207 ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4208 ext4_lblk_t ex_cluster_start, ex_cluster_end;
4209 ext4_lblk_t rr_cluster_start;
4210 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4211 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4212 unsigned short ee_len = ext4_ext_get_actual_len(ex);
4213
4214 /* The extent passed in that we are trying to match */
4215 ex_cluster_start = EXT4_B2C(sbi, ee_block);
4216 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4217
4218 /* The requested region passed into ext4_map_blocks() */
4219 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4220
4221 if ((rr_cluster_start == ex_cluster_end) ||
4222 (rr_cluster_start == ex_cluster_start)) {
4223 if (rr_cluster_start == ex_cluster_end)
4224 ee_start += ee_len - 1;
4225 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4226 map->m_len = min(map->m_len,
4227 (unsigned) sbi->s_cluster_ratio - c_offset);
4228 /*
4229 * Check for and handle this case:
4230 *
4231 * |--------- cluster # N-------------|
4232 * |------- extent ----|
4233 * |--- requested region ---|
4234 * |===========|
4235 */
4236
4237 if (map->m_lblk < ee_block)
4238 map->m_len = min(map->m_len, ee_block - map->m_lblk);
4239
4240 /*
4241 * Check for the case where there is already another allocated
4242 * block to the right of 'ex' but before the end of the cluster.
4243 *
4244 * |------------- cluster # N-------------|
4245 * |----- ex -----| |---- ex_right ----|
4246 * |------ requested region ------|
4247 * |================|
4248 */
4249 if (map->m_lblk > ee_block) {
4250 ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4251 map->m_len = min(map->m_len, next - map->m_lblk);
4252 }
4253
4254 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4255 return 1;
4256 }
4257
4258 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4259 return 0;
4260}
4261
4262
4263/*
4264 * Block allocation/map/preallocation routine for extents based files
4265 *
4266 *
4267 * Need to be called with
4268 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4269 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4270 *
4271 * return > 0, number of of blocks already mapped/allocated
4272 * if create == 0 and these are pre-allocated blocks
4273 * buffer head is unmapped
4274 * otherwise blocks are mapped
4275 *
4276 * return = 0, if plain look up failed (blocks have not been allocated)
4277 * buffer head is unmapped
4278 *
4279 * return < 0, error case.
4280 */
4281int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4282 struct ext4_map_blocks *map, int flags)
4283{
4284 struct ext4_ext_path *path = NULL;
4285 struct ext4_extent newex, *ex, *ex2;
4286 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4287 ext4_fsblk_t newblock = 0;
4288 int free_on_err = 0, err = 0, depth, ret;
4289 unsigned int allocated = 0, offset = 0;
4290 unsigned int allocated_clusters = 0;
4291 struct ext4_allocation_request ar;
4292 ext4_lblk_t cluster_offset;
4293 bool map_from_cluster = false;
4294
4295 ext_debug("blocks %u/%u requested for inode %lu\n",
4296 map->m_lblk, map->m_len, inode->i_ino);
4297 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4298
4299 /* find extent for this block */
4300 path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4301 if (IS_ERR(path)) {
4302 err = PTR_ERR(path);
4303 path = NULL;
4304 goto out2;
4305 }
4306
4307 depth = ext_depth(inode);
4308
4309 /*
4310 * consistent leaf must not be empty;
4311 * this situation is possible, though, _during_ tree modification;
4312 * this is why assert can't be put in ext4_find_extent()
4313 */
4314 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4315 EXT4_ERROR_INODE(inode, "bad extent address "
4316 "lblock: %lu, depth: %d pblock %lld",
4317 (unsigned long) map->m_lblk, depth,
4318 path[depth].p_block);
4319 err = -EFSCORRUPTED;
4320 goto out2;
4321 }
4322
4323 ex = path[depth].p_ext;
4324 if (ex) {
4325 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4326 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4327 unsigned short ee_len;
4328
4329
4330 /*
4331 * unwritten extents are treated as holes, except that
4332 * we split out initialized portions during a write.
4333 */
4334 ee_len = ext4_ext_get_actual_len(ex);
4335
4336 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4337
4338 /* if found extent covers block, simply return it */
4339 if (in_range(map->m_lblk, ee_block, ee_len)) {
4340 newblock = map->m_lblk - ee_block + ee_start;
4341 /* number of remaining blocks in the extent */
4342 allocated = ee_len - (map->m_lblk - ee_block);
4343 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4344 ee_block, ee_len, newblock);
4345
4346 /*
4347 * If the extent is initialized check whether the
4348 * caller wants to convert it to unwritten.
4349 */
4350 if ((!ext4_ext_is_unwritten(ex)) &&
4351 (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4352 allocated = convert_initialized_extent(
4353 handle, inode, map, &path,
4354 allocated);
4355 goto out2;
4356 } else if (!ext4_ext_is_unwritten(ex))
4357 goto out;
4358
4359 ret = ext4_ext_handle_unwritten_extents(
4360 handle, inode, map, &path, flags,
4361 allocated, newblock);
4362 if (ret < 0)
4363 err = ret;
4364 else
4365 allocated = ret;
4366 goto out2;
4367 }
4368 }
4369
4370 /*
4371 * requested block isn't allocated yet;
4372 * we couldn't try to create block if create flag is zero
4373 */
4374 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4375 ext4_lblk_t hole_start, hole_len;
4376
4377 hole_start = map->m_lblk;
4378 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4379 /*
4380 * put just found gap into cache to speed up
4381 * subsequent requests
4382 */
4383 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4384
4385 /* Update hole_len to reflect hole size after map->m_lblk */
4386 if (hole_start != map->m_lblk)
4387 hole_len -= map->m_lblk - hole_start;
4388 map->m_pblk = 0;
4389 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4390
4391 goto out2;
4392 }
4393
4394 /*
4395 * Okay, we need to do block allocation.
4396 */
4397 newex.ee_block = cpu_to_le32(map->m_lblk);
4398 cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4399
4400 /*
4401 * If we are doing bigalloc, check to see if the extent returned
4402 * by ext4_find_extent() implies a cluster we can use.
4403 */
4404 if (cluster_offset && ex &&
4405 get_implied_cluster_alloc(inode->i_sb, map, ex, 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 /* find neighbour allocated blocks */
4413 ar.lleft = map->m_lblk;
4414 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4415 if (err)
4416 goto out2;
4417 ar.lright = map->m_lblk;
4418 ex2 = NULL;
4419 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4420 if (err)
4421 goto out2;
4422
4423 /* Check if the extent after searching to the right implies a
4424 * cluster we can use. */
4425 if ((sbi->s_cluster_ratio > 1) && ex2 &&
4426 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4427 ar.len = allocated = map->m_len;
4428 newblock = map->m_pblk;
4429 map_from_cluster = true;
4430 goto got_allocated_blocks;
4431 }
4432
4433 /*
4434 * See if request is beyond maximum number of blocks we can have in
4435 * a single extent. For an initialized extent this limit is
4436 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4437 * EXT_UNWRITTEN_MAX_LEN.
4438 */
4439 if (map->m_len > EXT_INIT_MAX_LEN &&
4440 !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4441 map->m_len = EXT_INIT_MAX_LEN;
4442 else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4443 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4444 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4445
4446 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4447 newex.ee_len = cpu_to_le16(map->m_len);
4448 err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4449 if (err)
4450 allocated = ext4_ext_get_actual_len(&newex);
4451 else
4452 allocated = map->m_len;
4453
4454 /* allocate new block */
4455 ar.inode = inode;
4456 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4457 ar.logical = map->m_lblk;
4458 /*
4459 * We calculate the offset from the beginning of the cluster
4460 * for the logical block number, since when we allocate a
4461 * physical cluster, the physical block should start at the
4462 * same offset from the beginning of the cluster. This is
4463 * needed so that future calls to get_implied_cluster_alloc()
4464 * work correctly.
4465 */
4466 offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4467 ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4468 ar.goal -= offset;
4469 ar.logical -= offset;
4470 if (S_ISREG(inode->i_mode))
4471 ar.flags = EXT4_MB_HINT_DATA;
4472 else
4473 /* disable in-core preallocation for non-regular files */
4474 ar.flags = 0;
4475 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4476 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4477 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4478 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4479 if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4480 ar.flags |= EXT4_MB_USE_RESERVED;
4481 newblock = ext4_mb_new_blocks(handle, &ar, &err);
4482 if (!newblock)
4483 goto out2;
4484 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4485 ar.goal, newblock, allocated);
4486 free_on_err = 1;
4487 allocated_clusters = ar.len;
4488 ar.len = EXT4_C2B(sbi, ar.len) - offset;
4489 if (ar.len > allocated)
4490 ar.len = allocated;
4491
4492got_allocated_blocks:
4493 /* try to insert new extent into found leaf and return */
4494 ext4_ext_store_pblock(&newex, newblock + offset);
4495 newex.ee_len = cpu_to_le16(ar.len);
4496 /* Mark unwritten */
4497 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4498 ext4_ext_mark_unwritten(&newex);
4499 map->m_flags |= EXT4_MAP_UNWRITTEN;
4500 }
4501
4502 err = 0;
4503 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4504 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4505 path, ar.len);
4506 if (!err)
4507 err = ext4_ext_insert_extent(handle, inode, &path,
4508 &newex, flags);
4509
4510 if (err && free_on_err) {
4511 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4512 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4513 /* free data blocks we just allocated */
4514 /* not a good idea to call discard here directly,
4515 * but otherwise we'd need to call it every free() */
4516 ext4_discard_preallocations(inode);
4517 ext4_free_blocks(handle, inode, NULL, newblock,
4518 EXT4_C2B(sbi, allocated_clusters), fb_flags);
4519 goto out2;
4520 }
4521
4522 /* previous routine could use block we allocated */
4523 newblock = ext4_ext_pblock(&newex);
4524 allocated = ext4_ext_get_actual_len(&newex);
4525 if (allocated > map->m_len)
4526 allocated = map->m_len;
4527 map->m_flags |= EXT4_MAP_NEW;
4528
4529 /*
4530 * Update reserved blocks/metadata blocks after successful
4531 * block allocation which had been deferred till now.
4532 */
4533 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4534 unsigned int reserved_clusters;
4535 /*
4536 * Check how many clusters we had reserved this allocated range
4537 */
4538 reserved_clusters = get_reserved_cluster_alloc(inode,
4539 map->m_lblk, allocated);
4540 if (!map_from_cluster) {
4541 BUG_ON(allocated_clusters < reserved_clusters);
4542 if (reserved_clusters < allocated_clusters) {
4543 struct ext4_inode_info *ei = EXT4_I(inode);
4544 int reservation = allocated_clusters -
4545 reserved_clusters;
4546 /*
4547 * It seems we claimed few clusters outside of
4548 * the range of this allocation. We should give
4549 * it back to the reservation pool. This can
4550 * happen in the following case:
4551 *
4552 * * Suppose s_cluster_ratio is 4 (i.e., each
4553 * cluster has 4 blocks. Thus, the clusters
4554 * are [0-3],[4-7],[8-11]...
4555 * * First comes delayed allocation write for
4556 * logical blocks 10 & 11. Since there were no
4557 * previous delayed allocated blocks in the
4558 * range [8-11], we would reserve 1 cluster
4559 * for this write.
4560 * * Next comes write for logical blocks 3 to 8.
4561 * In this case, we will reserve 2 clusters
4562 * (for [0-3] and [4-7]; and not for [8-11] as
4563 * that range has a delayed allocated blocks.
4564 * Thus total reserved clusters now becomes 3.
4565 * * Now, during the delayed allocation writeout
4566 * time, we will first write blocks [3-8] and
4567 * allocate 3 clusters for writing these
4568 * blocks. Also, we would claim all these
4569 * three clusters above.
4570 * * Now when we come here to writeout the
4571 * blocks [10-11], we would expect to claim
4572 * the reservation of 1 cluster we had made
4573 * (and we would claim it since there are no
4574 * more delayed allocated blocks in the range
4575 * [8-11]. But our reserved cluster count had
4576 * already gone to 0.
4577 *
4578 * Thus, at the step 4 above when we determine
4579 * that there are still some unwritten delayed
4580 * allocated blocks outside of our current
4581 * block range, we should increment the
4582 * reserved clusters count so that when the
4583 * remaining blocks finally gets written, we
4584 * could claim them.
4585 */
4586 dquot_reserve_block(inode,
4587 EXT4_C2B(sbi, reservation));
4588 spin_lock(&ei->i_block_reservation_lock);
4589 ei->i_reserved_data_blocks += reservation;
4590 spin_unlock(&ei->i_block_reservation_lock);
4591 }
4592 /*
4593 * We will claim quota for all newly allocated blocks.
4594 * We're updating the reserved space *after* the
4595 * correction above so we do not accidentally free
4596 * all the metadata reservation because we might
4597 * actually need it later on.
4598 */
4599 ext4_da_update_reserve_space(inode, allocated_clusters,
4600 1);
4601 }
4602 }
4603
4604 /*
4605 * Cache the extent and update transaction to commit on fdatasync only
4606 * when it is _not_ an unwritten extent.
4607 */
4608 if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4609 ext4_update_inode_fsync_trans(handle, inode, 1);
4610 else
4611 ext4_update_inode_fsync_trans(handle, inode, 0);
4612out:
4613 if (allocated > map->m_len)
4614 allocated = map->m_len;
4615 ext4_ext_show_leaf(inode, path);
4616 map->m_flags |= EXT4_MAP_MAPPED;
4617 map->m_pblk = newblock;
4618 map->m_len = allocated;
4619out2:
4620 ext4_ext_drop_refs(path);
4621 kfree(path);
4622
4623 trace_ext4_ext_map_blocks_exit(inode, flags, map,
4624 err ? err : allocated);
4625 return err ? err : allocated;
4626}
4627
4628void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4629{
4630 struct super_block *sb = inode->i_sb;
4631 ext4_lblk_t last_block;
4632 int err = 0;
4633
4634 /*
4635 * TODO: optimization is possible here.
4636 * Probably we need not scan at all,
4637 * because page truncation is enough.
4638 */
4639
4640 /* we have to know where to truncate from in crash case */
4641 EXT4_I(inode)->i_disksize = inode->i_size;
4642 ext4_mark_inode_dirty(handle, inode);
4643
4644 last_block = (inode->i_size + sb->s_blocksize - 1)
4645 >> EXT4_BLOCK_SIZE_BITS(sb);
4646retry:
4647 err = ext4_es_remove_extent(inode, last_block,
4648 EXT_MAX_BLOCKS - last_block);
4649 if (err == -ENOMEM) {
4650 cond_resched();
4651 congestion_wait(BLK_RW_ASYNC, HZ/50);
4652 goto retry;
4653 }
4654 if (err) {
4655 ext4_std_error(inode->i_sb, err);
4656 return;
4657 }
4658 err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4659 ext4_std_error(inode->i_sb, err);
4660}
4661
4662static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4663 ext4_lblk_t len, loff_t new_size,
4664 int flags, int mode)
4665{
4666 struct inode *inode = file_inode(file);
4667 handle_t *handle;
4668 int ret = 0;
4669 int ret2 = 0;
4670 int retries = 0;
4671 int depth = 0;
4672 struct ext4_map_blocks map;
4673 unsigned int credits;
4674 loff_t epos;
4675
4676 map.m_lblk = offset;
4677 map.m_len = len;
4678 /*
4679 * Don't normalize the request if it can fit in one extent so
4680 * that it doesn't get unnecessarily split into multiple
4681 * extents.
4682 */
4683 if (len <= EXT_UNWRITTEN_MAX_LEN)
4684 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4685
4686 /*
4687 * credits to insert 1 extent into extent tree
4688 */
4689 credits = ext4_chunk_trans_blocks(inode, len);
4690 /*
4691 * We can only call ext_depth() on extent based inodes
4692 */
4693 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4694 depth = ext_depth(inode);
4695 else
4696 depth = -1;
4697
4698retry:
4699 while (ret >= 0 && len) {
4700 /*
4701 * Recalculate credits when extent tree depth changes.
4702 */
4703 if (depth >= 0 && depth != ext_depth(inode)) {
4704 credits = ext4_chunk_trans_blocks(inode, len);
4705 depth = ext_depth(inode);
4706 }
4707
4708 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4709 credits);
4710 if (IS_ERR(handle)) {
4711 ret = PTR_ERR(handle);
4712 break;
4713 }
4714 ret = ext4_map_blocks(handle, inode, &map, flags);
4715 if (ret <= 0) {
4716 ext4_debug("inode #%lu: block %u: len %u: "
4717 "ext4_ext_map_blocks returned %d",
4718 inode->i_ino, map.m_lblk,
4719 map.m_len, ret);
4720 ext4_mark_inode_dirty(handle, inode);
4721 ret2 = ext4_journal_stop(handle);
4722 break;
4723 }
4724 map.m_lblk += ret;
4725 map.m_len = len = len - ret;
4726 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4727 inode->i_ctime = ext4_current_time(inode);
4728 if (new_size) {
4729 if (epos > new_size)
4730 epos = new_size;
4731 if (ext4_update_inode_size(inode, epos) & 0x1)
4732 inode->i_mtime = inode->i_ctime;
4733 } else {
4734 if (epos > inode->i_size)
4735 ext4_set_inode_flag(inode,
4736 EXT4_INODE_EOFBLOCKS);
4737 }
4738 ext4_mark_inode_dirty(handle, inode);
4739 ret2 = ext4_journal_stop(handle);
4740 if (ret2)
4741 break;
4742 }
4743 if (ret == -ENOSPC &&
4744 ext4_should_retry_alloc(inode->i_sb, &retries)) {
4745 ret = 0;
4746 goto retry;
4747 }
4748
4749 return ret > 0 ? ret2 : ret;
4750}
4751
4752static long ext4_zero_range(struct file *file, loff_t offset,
4753 loff_t len, int mode)
4754{
4755 struct inode *inode = file_inode(file);
4756 handle_t *handle = NULL;
4757 unsigned int max_blocks;
4758 loff_t new_size = 0;
4759 int ret = 0;
4760 int flags;
4761 int credits;
4762 int partial_begin, partial_end;
4763 loff_t start, end;
4764 ext4_lblk_t lblk;
4765 unsigned int blkbits = inode->i_blkbits;
4766
4767 trace_ext4_zero_range(inode, offset, len, mode);
4768
4769 if (!S_ISREG(inode->i_mode))
4770 return -EINVAL;
4771
4772 /* Call ext4_force_commit to flush all data in case of data=journal. */
4773 if (ext4_should_journal_data(inode)) {
4774 ret = ext4_force_commit(inode->i_sb);
4775 if (ret)
4776 return ret;
4777 }
4778
4779 /*
4780 * Round up offset. This is not fallocate, we neet to zero out
4781 * blocks, so convert interior block aligned part of the range to
4782 * unwritten and possibly manually zero out unaligned parts of the
4783 * range.
4784 */
4785 start = round_up(offset, 1 << blkbits);
4786 end = round_down((offset + len), 1 << blkbits);
4787
4788 if (start < offset || end > offset + len)
4789 return -EINVAL;
4790 partial_begin = offset & ((1 << blkbits) - 1);
4791 partial_end = (offset + len) & ((1 << blkbits) - 1);
4792
4793 lblk = start >> blkbits;
4794 max_blocks = (end >> blkbits);
4795 if (max_blocks < lblk)
4796 max_blocks = 0;
4797 else
4798 max_blocks -= lblk;
4799
4800 inode_lock(inode);
4801
4802 /*
4803 * Indirect files do not support unwritten extnets
4804 */
4805 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4806 ret = -EOPNOTSUPP;
4807 goto out_mutex;
4808 }
4809
4810 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4811 offset + len > i_size_read(inode)) {
4812 new_size = offset + len;
4813 ret = inode_newsize_ok(inode, new_size);
4814 if (ret)
4815 goto out_mutex;
4816 }
4817
4818 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4819 if (mode & FALLOC_FL_KEEP_SIZE)
4820 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4821
4822 /* Wait all existing dio workers, newcomers will block on i_mutex */
4823 ext4_inode_block_unlocked_dio(inode);
4824 inode_dio_wait(inode);
4825
4826 /* Preallocate the range including the unaligned edges */
4827 if (partial_begin || partial_end) {
4828 ret = ext4_alloc_file_blocks(file,
4829 round_down(offset, 1 << blkbits) >> blkbits,
4830 (round_up((offset + len), 1 << blkbits) -
4831 round_down(offset, 1 << blkbits)) >> blkbits,
4832 new_size, flags, mode);
4833 if (ret)
4834 goto out_dio;
4835
4836 }
4837
4838 /* Zero range excluding the unaligned edges */
4839 if (max_blocks > 0) {
4840 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4841 EXT4_EX_NOCACHE);
4842
4843 /*
4844 * Prevent page faults from reinstantiating pages we have
4845 * released from page cache.
4846 */
4847 down_write(&EXT4_I(inode)->i_mmap_sem);
4848 ret = ext4_update_disksize_before_punch(inode, offset, len);
4849 if (ret) {
4850 up_write(&EXT4_I(inode)->i_mmap_sem);
4851 goto out_dio;
4852 }
4853 /* Now release the pages and zero block aligned part of pages */
4854 truncate_pagecache_range(inode, start, end - 1);
4855 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4856
4857 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4858 flags, mode);
4859 up_write(&EXT4_I(inode)->i_mmap_sem);
4860 if (ret)
4861 goto out_dio;
4862 }
4863 if (!partial_begin && !partial_end)
4864 goto out_dio;
4865
4866 /*
4867 * In worst case we have to writeout two nonadjacent unwritten
4868 * blocks and update the inode
4869 */
4870 credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4871 if (ext4_should_journal_data(inode))
4872 credits += 2;
4873 handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4874 if (IS_ERR(handle)) {
4875 ret = PTR_ERR(handle);
4876 ext4_std_error(inode->i_sb, ret);
4877 goto out_dio;
4878 }
4879
4880 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4881 if (new_size) {
4882 ext4_update_inode_size(inode, new_size);
4883 } else {
4884 /*
4885 * Mark that we allocate beyond EOF so the subsequent truncate
4886 * can proceed even if the new size is the same as i_size.
4887 */
4888 if ((offset + len) > i_size_read(inode))
4889 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4890 }
4891 ext4_mark_inode_dirty(handle, inode);
4892
4893 /* Zero out partial block at the edges of the range */
4894 ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4895
4896 if (file->f_flags & O_SYNC)
4897 ext4_handle_sync(handle);
4898
4899 ext4_journal_stop(handle);
4900out_dio:
4901 ext4_inode_resume_unlocked_dio(inode);
4902out_mutex:
4903 inode_unlock(inode);
4904 return ret;
4905}
4906
4907/*
4908 * preallocate space for a file. This implements ext4's fallocate file
4909 * operation, which gets called from sys_fallocate system call.
4910 * For block-mapped files, posix_fallocate should fall back to the method
4911 * of writing zeroes to the required new blocks (the same behavior which is
4912 * expected for file systems which do not support fallocate() system call).
4913 */
4914long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4915{
4916 struct inode *inode = file_inode(file);
4917 loff_t new_size = 0;
4918 unsigned int max_blocks;
4919 int ret = 0;
4920 int flags;
4921 ext4_lblk_t lblk;
4922 unsigned int blkbits = inode->i_blkbits;
4923
4924 /*
4925 * Encrypted inodes can't handle collapse range or insert
4926 * range since we would need to re-encrypt blocks with a
4927 * different IV or XTS tweak (which are based on the logical
4928 * block number).
4929 *
4930 * XXX It's not clear why zero range isn't working, but we'll
4931 * leave it disabled for encrypted inodes for now. This is a
4932 * bug we should fix....
4933 */
4934 if (ext4_encrypted_inode(inode) &&
4935 (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4936 FALLOC_FL_ZERO_RANGE)))
4937 return -EOPNOTSUPP;
4938
4939 /* Return error if mode is not supported */
4940 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4941 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4942 FALLOC_FL_INSERT_RANGE))
4943 return -EOPNOTSUPP;
4944
4945 if (mode & FALLOC_FL_PUNCH_HOLE)
4946 return ext4_punch_hole(inode, offset, len);
4947
4948 ret = ext4_convert_inline_data(inode);
4949 if (ret)
4950 return ret;
4951
4952 if (mode & FALLOC_FL_COLLAPSE_RANGE)
4953 return ext4_collapse_range(inode, offset, len);
4954
4955 if (mode & FALLOC_FL_INSERT_RANGE)
4956 return ext4_insert_range(inode, offset, len);
4957
4958 if (mode & FALLOC_FL_ZERO_RANGE)
4959 return ext4_zero_range(file, offset, len, mode);
4960
4961 trace_ext4_fallocate_enter(inode, offset, len, mode);
4962 lblk = offset >> blkbits;
4963 /*
4964 * We can't just convert len to max_blocks because
4965 * If blocksize = 4096 offset = 3072 and len = 2048
4966 */
4967 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4968 - lblk;
4969
4970 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4971 if (mode & FALLOC_FL_KEEP_SIZE)
4972 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4973
4974 inode_lock(inode);
4975
4976 /*
4977 * We only support preallocation for extent-based files only
4978 */
4979 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4980 ret = -EOPNOTSUPP;
4981 goto out;
4982 }
4983
4984 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4985 offset + len > i_size_read(inode)) {
4986 new_size = offset + len;
4987 ret = inode_newsize_ok(inode, new_size);
4988 if (ret)
4989 goto out;
4990 }
4991
4992 /* Wait all existing dio workers, newcomers will block on i_mutex */
4993 ext4_inode_block_unlocked_dio(inode);
4994 inode_dio_wait(inode);
4995
4996 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4997 flags, mode);
4998 ext4_inode_resume_unlocked_dio(inode);
4999 if (ret)
5000 goto out;
5001
5002 if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
5003 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5004 EXT4_I(inode)->i_sync_tid);
5005 }
5006out:
5007 inode_unlock(inode);
5008 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
5009 return ret;
5010}
5011
5012/*
5013 * This function convert a range of blocks to written extents
5014 * The caller of this function will pass the start offset and the size.
5015 * all unwritten extents within this range will be converted to
5016 * written extents.
5017 *
5018 * This function is called from the direct IO end io call back
5019 * function, to convert the fallocated extents after IO is completed.
5020 * Returns 0 on success.
5021 */
5022int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5023 loff_t offset, ssize_t len)
5024{
5025 unsigned int max_blocks;
5026 int ret = 0;
5027 int ret2 = 0;
5028 struct ext4_map_blocks map;
5029 unsigned int credits, blkbits = inode->i_blkbits;
5030
5031 map.m_lblk = offset >> blkbits;
5032 /*
5033 * We can't just convert len to max_blocks because
5034 * If blocksize = 4096 offset = 3072 and len = 2048
5035 */
5036 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5037 map.m_lblk);
5038 /*
5039 * This is somewhat ugly but the idea is clear: When transaction is
5040 * reserved, everything goes into it. Otherwise we rather start several
5041 * smaller transactions for conversion of each extent separately.
5042 */
5043 if (handle) {
5044 handle = ext4_journal_start_reserved(handle,
5045 EXT4_HT_EXT_CONVERT);
5046 if (IS_ERR(handle))
5047 return PTR_ERR(handle);
5048 credits = 0;
5049 } else {
5050 /*
5051 * credits to insert 1 extent into extent tree
5052 */
5053 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5054 }
5055 while (ret >= 0 && ret < max_blocks) {
5056 map.m_lblk += ret;
5057 map.m_len = (max_blocks -= ret);
5058 if (credits) {
5059 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5060 credits);
5061 if (IS_ERR(handle)) {
5062 ret = PTR_ERR(handle);
5063 break;
5064 }
5065 }
5066 ret = ext4_map_blocks(handle, inode, &map,
5067 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5068 if (ret <= 0)
5069 ext4_warning(inode->i_sb,
5070 "inode #%lu: block %u: len %u: "
5071 "ext4_ext_map_blocks returned %d",
5072 inode->i_ino, map.m_lblk,
5073 map.m_len, ret);
5074 ext4_mark_inode_dirty(handle, inode);
5075 if (credits)
5076 ret2 = ext4_journal_stop(handle);
5077 if (ret <= 0 || ret2)
5078 break;
5079 }
5080 if (!credits)
5081 ret2 = ext4_journal_stop(handle);
5082 return ret > 0 ? ret2 : ret;
5083}
5084
5085/*
5086 * If newes is not existing extent (newes->ec_pblk equals zero) find
5087 * delayed extent at start of newes and update newes accordingly and
5088 * return start of the next delayed extent.
5089 *
5090 * If newes is existing extent (newes->ec_pblk is not equal zero)
5091 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5092 * extent found. Leave newes unmodified.
5093 */
5094static int ext4_find_delayed_extent(struct inode *inode,
5095 struct extent_status *newes)
5096{
5097 struct extent_status es;
5098 ext4_lblk_t block, next_del;
5099
5100 if (newes->es_pblk == 0) {
5101 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5102 newes->es_lblk + newes->es_len - 1, &es);
5103
5104 /*
5105 * No extent in extent-tree contains block @newes->es_pblk,
5106 * then the block may stay in 1)a hole or 2)delayed-extent.
5107 */
5108 if (es.es_len == 0)
5109 /* A hole found. */
5110 return 0;
5111
5112 if (es.es_lblk > newes->es_lblk) {
5113 /* A hole found. */
5114 newes->es_len = min(es.es_lblk - newes->es_lblk,
5115 newes->es_len);
5116 return 0;
5117 }
5118
5119 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5120 }
5121
5122 block = newes->es_lblk + newes->es_len;
5123 ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5124 if (es.es_len == 0)
5125 next_del = EXT_MAX_BLOCKS;
5126 else
5127 next_del = es.es_lblk;
5128
5129 return next_del;
5130}
5131/* fiemap flags we can handle specified here */
5132#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5133
5134static int ext4_xattr_fiemap(struct inode *inode,
5135 struct fiemap_extent_info *fieinfo)
5136{
5137 __u64 physical = 0;
5138 __u64 length;
5139 __u32 flags = FIEMAP_EXTENT_LAST;
5140 int blockbits = inode->i_sb->s_blocksize_bits;
5141 int error = 0;
5142
5143 /* in-inode? */
5144 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5145 struct ext4_iloc iloc;
5146 int offset; /* offset of xattr in inode */
5147
5148 error = ext4_get_inode_loc(inode, &iloc);
5149 if (error)
5150 return error;
5151 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5152 offset = EXT4_GOOD_OLD_INODE_SIZE +
5153 EXT4_I(inode)->i_extra_isize;
5154 physical += offset;
5155 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5156 flags |= FIEMAP_EXTENT_DATA_INLINE;
5157 brelse(iloc.bh);
5158 } else { /* external block */
5159 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5160 length = inode->i_sb->s_blocksize;
5161 }
5162
5163 if (physical)
5164 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5165 length, flags);
5166 return (error < 0 ? error : 0);
5167}
5168
5169int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5170 __u64 start, __u64 len)
5171{
5172 ext4_lblk_t start_blk;
5173 int error = 0;
5174
5175 if (ext4_has_inline_data(inode)) {
5176 int has_inline = 1;
5177
5178 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5179 start, len);
5180
5181 if (has_inline)
5182 return error;
5183 }
5184
5185 if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5186 error = ext4_ext_precache(inode);
5187 if (error)
5188 return error;
5189 }
5190
5191 /* fallback to generic here if not in extents fmt */
5192 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5193 return generic_block_fiemap(inode, fieinfo, start, len,
5194 ext4_get_block);
5195
5196 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5197 return -EBADR;
5198
5199 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5200 error = ext4_xattr_fiemap(inode, fieinfo);
5201 } else {
5202 ext4_lblk_t len_blks;
5203 __u64 last_blk;
5204
5205 start_blk = start >> inode->i_sb->s_blocksize_bits;
5206 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5207 if (last_blk >= EXT_MAX_BLOCKS)
5208 last_blk = EXT_MAX_BLOCKS-1;
5209 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5210
5211 /*
5212 * Walk the extent tree gathering extent information
5213 * and pushing extents back to the user.
5214 */
5215 error = ext4_fill_fiemap_extents(inode, start_blk,
5216 len_blks, fieinfo);
5217 }
5218 return error;
5219}
5220
5221/*
5222 * ext4_access_path:
5223 * Function to access the path buffer for marking it dirty.
5224 * It also checks if there are sufficient credits left in the journal handle
5225 * to update path.
5226 */
5227static int
5228ext4_access_path(handle_t *handle, struct inode *inode,
5229 struct ext4_ext_path *path)
5230{
5231 int credits, err;
5232
5233 if (!ext4_handle_valid(handle))
5234 return 0;
5235
5236 /*
5237 * Check if need to extend journal credits
5238 * 3 for leaf, sb, and inode plus 2 (bmap and group
5239 * descriptor) for each block group; assume two block
5240 * groups
5241 */
5242 if (handle->h_buffer_credits < 7) {
5243 credits = ext4_writepage_trans_blocks(inode);
5244 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5245 /* EAGAIN is success */
5246 if (err && err != -EAGAIN)
5247 return err;
5248 }
5249
5250 err = ext4_ext_get_access(handle, inode, path);
5251 return err;
5252}
5253
5254/*
5255 * ext4_ext_shift_path_extents:
5256 * Shift the extents of a path structure lying between path[depth].p_ext
5257 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5258 * if it is right shift or left shift operation.
5259 */
5260static int
5261ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5262 struct inode *inode, handle_t *handle,
5263 enum SHIFT_DIRECTION SHIFT)
5264{
5265 int depth, err = 0;
5266 struct ext4_extent *ex_start, *ex_last;
5267 bool update = 0;
5268 depth = path->p_depth;
5269
5270 while (depth >= 0) {
5271 if (depth == path->p_depth) {
5272 ex_start = path[depth].p_ext;
5273 if (!ex_start)
5274 return -EFSCORRUPTED;
5275
5276 ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5277
5278 err = ext4_access_path(handle, inode, path + depth);
5279 if (err)
5280 goto out;
5281
5282 if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5283 update = 1;
5284
5285 while (ex_start <= ex_last) {
5286 if (SHIFT == SHIFT_LEFT) {
5287 le32_add_cpu(&ex_start->ee_block,
5288 -shift);
5289 /* Try to merge to the left. */
5290 if ((ex_start >
5291 EXT_FIRST_EXTENT(path[depth].p_hdr))
5292 &&
5293 ext4_ext_try_to_merge_right(inode,
5294 path, ex_start - 1))
5295 ex_last--;
5296 else
5297 ex_start++;
5298 } else {
5299 le32_add_cpu(&ex_last->ee_block, shift);
5300 ext4_ext_try_to_merge_right(inode, path,
5301 ex_last);
5302 ex_last--;
5303 }
5304 }
5305 err = ext4_ext_dirty(handle, inode, path + depth);
5306 if (err)
5307 goto out;
5308
5309 if (--depth < 0 || !update)
5310 break;
5311 }
5312
5313 /* Update index too */
5314 err = ext4_access_path(handle, inode, path + depth);
5315 if (err)
5316 goto out;
5317
5318 if (SHIFT == SHIFT_LEFT)
5319 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5320 else
5321 le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5322 err = ext4_ext_dirty(handle, inode, path + depth);
5323 if (err)
5324 goto out;
5325
5326 /* we are done if current index is not a starting index */
5327 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5328 break;
5329
5330 depth--;
5331 }
5332
5333out:
5334 return err;
5335}
5336
5337/*
5338 * ext4_ext_shift_extents:
5339 * All the extents which lies in the range from @start to the last allocated
5340 * block for the @inode are shifted either towards left or right (depending
5341 * upon @SHIFT) by @shift blocks.
5342 * On success, 0 is returned, error otherwise.
5343 */
5344static int
5345ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5346 ext4_lblk_t start, ext4_lblk_t shift,
5347 enum SHIFT_DIRECTION SHIFT)
5348{
5349 struct ext4_ext_path *path;
5350 int ret = 0, depth;
5351 struct ext4_extent *extent;
5352 ext4_lblk_t stop, *iterator, ex_start, ex_end;
5353
5354 /* Let path point to the last extent */
5355 path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5356 if (IS_ERR(path))
5357 return PTR_ERR(path);
5358
5359 depth = path->p_depth;
5360 extent = path[depth].p_ext;
5361 if (!extent)
5362 goto out;
5363
5364 stop = le32_to_cpu(extent->ee_block) +
5365 ext4_ext_get_actual_len(extent);
5366
5367 /*
5368 * In case of left shift, Don't start shifting extents until we make
5369 * sure the hole is big enough to accommodate the shift.
5370 */
5371 if (SHIFT == SHIFT_LEFT) {
5372 path = ext4_find_extent(inode, start - 1, &path, 0);
5373 if (IS_ERR(path))
5374 return PTR_ERR(path);
5375 depth = path->p_depth;
5376 extent = path[depth].p_ext;
5377 if (extent) {
5378 ex_start = le32_to_cpu(extent->ee_block);
5379 ex_end = le32_to_cpu(extent->ee_block) +
5380 ext4_ext_get_actual_len(extent);
5381 } else {
5382 ex_start = 0;
5383 ex_end = 0;
5384 }
5385
5386 if ((start == ex_start && shift > ex_start) ||
5387 (shift > start - ex_end)) {
5388 ext4_ext_drop_refs(path);
5389 kfree(path);
5390 return -EINVAL;
5391 }
5392 }
5393
5394 /*
5395 * In case of left shift, iterator points to start and it is increased
5396 * till we reach stop. In case of right shift, iterator points to stop
5397 * and it is decreased till we reach start.
5398 */
5399 if (SHIFT == SHIFT_LEFT)
5400 iterator = &start;
5401 else
5402 iterator = &stop;
5403
5404 /* Its safe to start updating extents */
5405 while (start < stop) {
5406 path = ext4_find_extent(inode, *iterator, &path, 0);
5407 if (IS_ERR(path))
5408 return PTR_ERR(path);
5409 depth = path->p_depth;
5410 extent = path[depth].p_ext;
5411 if (!extent) {
5412 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5413 (unsigned long) *iterator);
5414 return -EFSCORRUPTED;
5415 }
5416 if (SHIFT == SHIFT_LEFT && *iterator >
5417 le32_to_cpu(extent->ee_block)) {
5418 /* Hole, move to the next extent */
5419 if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5420 path[depth].p_ext++;
5421 } else {
5422 *iterator = ext4_ext_next_allocated_block(path);
5423 continue;
5424 }
5425 }
5426
5427 if (SHIFT == SHIFT_LEFT) {
5428 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5429 *iterator = le32_to_cpu(extent->ee_block) +
5430 ext4_ext_get_actual_len(extent);
5431 } else {
5432 extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5433 *iterator = le32_to_cpu(extent->ee_block) > 0 ?
5434 le32_to_cpu(extent->ee_block) - 1 : 0;
5435 /* Update path extent in case we need to stop */
5436 while (le32_to_cpu(extent->ee_block) < start)
5437 extent++;
5438 path[depth].p_ext = extent;
5439 }
5440 ret = ext4_ext_shift_path_extents(path, shift, inode,
5441 handle, SHIFT);
5442 if (ret)
5443 break;
5444 }
5445out:
5446 ext4_ext_drop_refs(path);
5447 kfree(path);
5448 return ret;
5449}
5450
5451/*
5452 * ext4_collapse_range:
5453 * This implements the fallocate's collapse range functionality for ext4
5454 * Returns: 0 and non-zero on error.
5455 */
5456int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5457{
5458 struct super_block *sb = inode->i_sb;
5459 ext4_lblk_t punch_start, punch_stop;
5460 handle_t *handle;
5461 unsigned int credits;
5462 loff_t new_size, ioffset;
5463 int ret;
5464
5465 /*
5466 * We need to test this early because xfstests assumes that a
5467 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5468 * system does not support collapse range.
5469 */
5470 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5471 return -EOPNOTSUPP;
5472
5473 /* Collapse range works only on fs block size aligned offsets. */
5474 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5475 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5476 return -EINVAL;
5477
5478 if (!S_ISREG(inode->i_mode))
5479 return -EINVAL;
5480
5481 trace_ext4_collapse_range(inode, offset, len);
5482
5483 punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5484 punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5485
5486 /* Call ext4_force_commit to flush all data in case of data=journal. */
5487 if (ext4_should_journal_data(inode)) {
5488 ret = ext4_force_commit(inode->i_sb);
5489 if (ret)
5490 return ret;
5491 }
5492
5493 inode_lock(inode);
5494 /*
5495 * There is no need to overlap collapse range with EOF, in which case
5496 * it is effectively a truncate operation
5497 */
5498 if (offset + len >= i_size_read(inode)) {
5499 ret = -EINVAL;
5500 goto out_mutex;
5501 }
5502
5503 /* Currently just for extent based files */
5504 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5505 ret = -EOPNOTSUPP;
5506 goto out_mutex;
5507 }
5508
5509 /* Wait for existing dio to complete */
5510 ext4_inode_block_unlocked_dio(inode);
5511 inode_dio_wait(inode);
5512
5513 /*
5514 * Prevent page faults from reinstantiating pages we have released from
5515 * page cache.
5516 */
5517 down_write(&EXT4_I(inode)->i_mmap_sem);
5518 /*
5519 * Need to round down offset to be aligned with page size boundary
5520 * for page size > block size.
5521 */
5522 ioffset = round_down(offset, PAGE_SIZE);
5523 /*
5524 * Write tail of the last page before removed range since it will get
5525 * removed from the page cache below.
5526 */
5527 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5528 if (ret)
5529 goto out_mmap;
5530 /*
5531 * Write data that will be shifted to preserve them when discarding
5532 * page cache below. We are also protected from pages becoming dirty
5533 * by i_mmap_sem.
5534 */
5535 ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5536 LLONG_MAX);
5537 if (ret)
5538 goto out_mmap;
5539 truncate_pagecache(inode, ioffset);
5540
5541 credits = ext4_writepage_trans_blocks(inode);
5542 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5543 if (IS_ERR(handle)) {
5544 ret = PTR_ERR(handle);
5545 goto out_mmap;
5546 }
5547
5548 down_write(&EXT4_I(inode)->i_data_sem);
5549 ext4_discard_preallocations(inode);
5550
5551 ret = ext4_es_remove_extent(inode, punch_start,
5552 EXT_MAX_BLOCKS - punch_start);
5553 if (ret) {
5554 up_write(&EXT4_I(inode)->i_data_sem);
5555 goto out_stop;
5556 }
5557
5558 ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5559 if (ret) {
5560 up_write(&EXT4_I(inode)->i_data_sem);
5561 goto out_stop;
5562 }
5563 ext4_discard_preallocations(inode);
5564
5565 ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5566 punch_stop - punch_start, SHIFT_LEFT);
5567 if (ret) {
5568 up_write(&EXT4_I(inode)->i_data_sem);
5569 goto out_stop;
5570 }
5571
5572 new_size = i_size_read(inode) - len;
5573 i_size_write(inode, new_size);
5574 EXT4_I(inode)->i_disksize = new_size;
5575
5576 up_write(&EXT4_I(inode)->i_data_sem);
5577 if (IS_SYNC(inode))
5578 ext4_handle_sync(handle);
5579 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5580 ext4_mark_inode_dirty(handle, inode);
5581
5582out_stop:
5583 ext4_journal_stop(handle);
5584out_mmap:
5585 up_write(&EXT4_I(inode)->i_mmap_sem);
5586 ext4_inode_resume_unlocked_dio(inode);
5587out_mutex:
5588 inode_unlock(inode);
5589 return ret;
5590}
5591
5592/*
5593 * ext4_insert_range:
5594 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5595 * The data blocks starting from @offset to the EOF are shifted by @len
5596 * towards right to create a hole in the @inode. Inode size is increased
5597 * by len bytes.
5598 * Returns 0 on success, error otherwise.
5599 */
5600int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5601{
5602 struct super_block *sb = inode->i_sb;
5603 handle_t *handle;
5604 struct ext4_ext_path *path;
5605 struct ext4_extent *extent;
5606 ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5607 unsigned int credits, ee_len;
5608 int ret = 0, depth, split_flag = 0;
5609 loff_t ioffset;
5610
5611 /*
5612 * We need to test this early because xfstests assumes that an
5613 * insert range of (0, 1) will return EOPNOTSUPP if the file
5614 * system does not support insert range.
5615 */
5616 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5617 return -EOPNOTSUPP;
5618
5619 /* Insert range works only on fs block size aligned offsets. */
5620 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5621 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5622 return -EINVAL;
5623
5624 if (!S_ISREG(inode->i_mode))
5625 return -EOPNOTSUPP;
5626
5627 trace_ext4_insert_range(inode, offset, len);
5628
5629 offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5630 len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5631
5632 /* Call ext4_force_commit to flush all data in case of data=journal */
5633 if (ext4_should_journal_data(inode)) {
5634 ret = ext4_force_commit(inode->i_sb);
5635 if (ret)
5636 return ret;
5637 }
5638
5639 inode_lock(inode);
5640 /* Currently just for extent based files */
5641 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5642 ret = -EOPNOTSUPP;
5643 goto out_mutex;
5644 }
5645
5646 /* Check for wrap through zero */
5647 if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5648 ret = -EFBIG;
5649 goto out_mutex;
5650 }
5651
5652 /* Offset should be less than i_size */
5653 if (offset >= i_size_read(inode)) {
5654 ret = -EINVAL;
5655 goto out_mutex;
5656 }
5657
5658 /* Wait for existing dio to complete */
5659 ext4_inode_block_unlocked_dio(inode);
5660 inode_dio_wait(inode);
5661
5662 /*
5663 * Prevent page faults from reinstantiating pages we have released from
5664 * page cache.
5665 */
5666 down_write(&EXT4_I(inode)->i_mmap_sem);
5667 /*
5668 * Need to round down to align start offset to page size boundary
5669 * for page size > block size.
5670 */
5671 ioffset = round_down(offset, PAGE_SIZE);
5672 /* Write out all dirty pages */
5673 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5674 LLONG_MAX);
5675 if (ret)
5676 goto out_mmap;
5677 truncate_pagecache(inode, ioffset);
5678
5679 credits = ext4_writepage_trans_blocks(inode);
5680 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5681 if (IS_ERR(handle)) {
5682 ret = PTR_ERR(handle);
5683 goto out_mmap;
5684 }
5685
5686 /* Expand file to avoid data loss if there is error while shifting */
5687 inode->i_size += len;
5688 EXT4_I(inode)->i_disksize += len;
5689 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5690 ret = ext4_mark_inode_dirty(handle, inode);
5691 if (ret)
5692 goto out_stop;
5693
5694 down_write(&EXT4_I(inode)->i_data_sem);
5695 ext4_discard_preallocations(inode);
5696
5697 path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5698 if (IS_ERR(path)) {
5699 up_write(&EXT4_I(inode)->i_data_sem);
5700 goto out_stop;
5701 }
5702
5703 depth = ext_depth(inode);
5704 extent = path[depth].p_ext;
5705 if (extent) {
5706 ee_start_lblk = le32_to_cpu(extent->ee_block);
5707 ee_len = ext4_ext_get_actual_len(extent);
5708
5709 /*
5710 * If offset_lblk is not the starting block of extent, split
5711 * the extent @offset_lblk
5712 */
5713 if ((offset_lblk > ee_start_lblk) &&
5714 (offset_lblk < (ee_start_lblk + ee_len))) {
5715 if (ext4_ext_is_unwritten(extent))
5716 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5717 EXT4_EXT_MARK_UNWRIT2;
5718 ret = ext4_split_extent_at(handle, inode, &path,
5719 offset_lblk, split_flag,
5720 EXT4_EX_NOCACHE |
5721 EXT4_GET_BLOCKS_PRE_IO |
5722 EXT4_GET_BLOCKS_METADATA_NOFAIL);
5723 }
5724
5725 ext4_ext_drop_refs(path);
5726 kfree(path);
5727 if (ret < 0) {
5728 up_write(&EXT4_I(inode)->i_data_sem);
5729 goto out_stop;
5730 }
5731 }
5732
5733 ret = ext4_es_remove_extent(inode, offset_lblk,
5734 EXT_MAX_BLOCKS - offset_lblk);
5735 if (ret) {
5736 up_write(&EXT4_I(inode)->i_data_sem);
5737 goto out_stop;
5738 }
5739
5740 /*
5741 * if offset_lblk lies in a hole which is at start of file, use
5742 * ee_start_lblk to shift extents
5743 */
5744 ret = ext4_ext_shift_extents(inode, handle,
5745 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5746 len_lblk, SHIFT_RIGHT);
5747
5748 up_write(&EXT4_I(inode)->i_data_sem);
5749 if (IS_SYNC(inode))
5750 ext4_handle_sync(handle);
5751
5752out_stop:
5753 ext4_journal_stop(handle);
5754out_mmap:
5755 up_write(&EXT4_I(inode)->i_mmap_sem);
5756 ext4_inode_resume_unlocked_dio(inode);
5757out_mutex:
5758 inode_unlock(inode);
5759 return ret;
5760}
5761
5762/**
5763 * ext4_swap_extents - Swap extents between two inodes
5764 *
5765 * @inode1: First inode
5766 * @inode2: Second inode
5767 * @lblk1: Start block for first inode
5768 * @lblk2: Start block for second inode
5769 * @count: Number of blocks to swap
5770 * @mark_unwritten: Mark second inode's extents as unwritten after swap
5771 * @erp: Pointer to save error value
5772 *
5773 * This helper routine does exactly what is promise "swap extents". All other
5774 * stuff such as page-cache locking consistency, bh mapping consistency or
5775 * extent's data copying must be performed by caller.
5776 * Locking:
5777 * i_mutex is held for both inodes
5778 * i_data_sem is locked for write for both inodes
5779 * Assumptions:
5780 * All pages from requested range are locked for both inodes
5781 */
5782int
5783ext4_swap_extents(handle_t *handle, struct inode *inode1,
5784 struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5785 ext4_lblk_t count, int unwritten, int *erp)
5786{
5787 struct ext4_ext_path *path1 = NULL;
5788 struct ext4_ext_path *path2 = NULL;
5789 int replaced_count = 0;
5790
5791 BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5792 BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5793 BUG_ON(!inode_is_locked(inode1));
5794 BUG_ON(!inode_is_locked(inode2));
5795
5796 *erp = ext4_es_remove_extent(inode1, lblk1, count);
5797 if (unlikely(*erp))
5798 return 0;
5799 *erp = ext4_es_remove_extent(inode2, lblk2, count);
5800 if (unlikely(*erp))
5801 return 0;
5802
5803 while (count) {
5804 struct ext4_extent *ex1, *ex2, tmp_ex;
5805 ext4_lblk_t e1_blk, e2_blk;
5806 int e1_len, e2_len, len;
5807 int split = 0;
5808
5809 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5810 if (IS_ERR(path1)) {
5811 *erp = PTR_ERR(path1);
5812 path1 = NULL;
5813 finish:
5814 count = 0;
5815 goto repeat;
5816 }
5817 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5818 if (IS_ERR(path2)) {
5819 *erp = PTR_ERR(path2);
5820 path2 = NULL;
5821 goto finish;
5822 }
5823 ex1 = path1[path1->p_depth].p_ext;
5824 ex2 = path2[path2->p_depth].p_ext;
5825 /* Do we have somthing to swap ? */
5826 if (unlikely(!ex2 || !ex1))
5827 goto finish;
5828
5829 e1_blk = le32_to_cpu(ex1->ee_block);
5830 e2_blk = le32_to_cpu(ex2->ee_block);
5831 e1_len = ext4_ext_get_actual_len(ex1);
5832 e2_len = ext4_ext_get_actual_len(ex2);
5833
5834 /* Hole handling */
5835 if (!in_range(lblk1, e1_blk, e1_len) ||
5836 !in_range(lblk2, e2_blk, e2_len)) {
5837 ext4_lblk_t next1, next2;
5838
5839 /* if hole after extent, then go to next extent */
5840 next1 = ext4_ext_next_allocated_block(path1);
5841 next2 = ext4_ext_next_allocated_block(path2);
5842 /* If hole before extent, then shift to that extent */
5843 if (e1_blk > lblk1)
5844 next1 = e1_blk;
5845 if (e2_blk > lblk2)
5846 next2 = e1_blk;
5847 /* Do we have something to swap */
5848 if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5849 goto finish;
5850 /* Move to the rightest boundary */
5851 len = next1 - lblk1;
5852 if (len < next2 - lblk2)
5853 len = next2 - lblk2;
5854 if (len > count)
5855 len = count;
5856 lblk1 += len;
5857 lblk2 += len;
5858 count -= len;
5859 goto repeat;
5860 }
5861
5862 /* Prepare left boundary */
5863 if (e1_blk < lblk1) {
5864 split = 1;
5865 *erp = ext4_force_split_extent_at(handle, inode1,
5866 &path1, lblk1, 0);
5867 if (unlikely(*erp))
5868 goto finish;
5869 }
5870 if (e2_blk < lblk2) {
5871 split = 1;
5872 *erp = ext4_force_split_extent_at(handle, inode2,
5873 &path2, lblk2, 0);
5874 if (unlikely(*erp))
5875 goto finish;
5876 }
5877 /* ext4_split_extent_at() may result in leaf extent split,
5878 * path must to be revalidated. */
5879 if (split)
5880 goto repeat;
5881
5882 /* Prepare right boundary */
5883 len = count;
5884 if (len > e1_blk + e1_len - lblk1)
5885 len = e1_blk + e1_len - lblk1;
5886 if (len > e2_blk + e2_len - lblk2)
5887 len = e2_blk + e2_len - lblk2;
5888
5889 if (len != e1_len) {
5890 split = 1;
5891 *erp = ext4_force_split_extent_at(handle, inode1,
5892 &path1, lblk1 + len, 0);
5893 if (unlikely(*erp))
5894 goto finish;
5895 }
5896 if (len != e2_len) {
5897 split = 1;
5898 *erp = ext4_force_split_extent_at(handle, inode2,
5899 &path2, lblk2 + len, 0);
5900 if (*erp)
5901 goto finish;
5902 }
5903 /* ext4_split_extent_at() may result in leaf extent split,
5904 * path must to be revalidated. */
5905 if (split)
5906 goto repeat;
5907
5908 BUG_ON(e2_len != e1_len);
5909 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5910 if (unlikely(*erp))
5911 goto finish;
5912 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5913 if (unlikely(*erp))
5914 goto finish;
5915
5916 /* Both extents are fully inside boundaries. Swap it now */
5917 tmp_ex = *ex1;
5918 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5919 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5920 ex1->ee_len = cpu_to_le16(e2_len);
5921 ex2->ee_len = cpu_to_le16(e1_len);
5922 if (unwritten)
5923 ext4_ext_mark_unwritten(ex2);
5924 if (ext4_ext_is_unwritten(&tmp_ex))
5925 ext4_ext_mark_unwritten(ex1);
5926
5927 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5928 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5929 *erp = ext4_ext_dirty(handle, inode2, path2 +
5930 path2->p_depth);
5931 if (unlikely(*erp))
5932 goto finish;
5933 *erp = ext4_ext_dirty(handle, inode1, path1 +
5934 path1->p_depth);
5935 /*
5936 * Looks scarry ah..? second inode already points to new blocks,
5937 * and it was successfully dirtied. But luckily error may happen
5938 * only due to journal error, so full transaction will be
5939 * aborted anyway.
5940 */
5941 if (unlikely(*erp))
5942 goto finish;
5943 lblk1 += len;
5944 lblk2 += len;
5945 replaced_count += len;
5946 count -= len;
5947
5948 repeat:
5949 ext4_ext_drop_refs(path1);
5950 kfree(path1);
5951 ext4_ext_drop_refs(path2);
5952 kfree(path2);
5953 path1 = path2 = NULL;
5954 }
5955 return replaced_count;
5956}