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