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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/module.h>
33#include <linux/fs.h>
34#include <linux/time.h>
35#include <linux/jbd2.h>
36#include <linux/highuid.h>
37#include <linux/pagemap.h>
38#include <linux/quotaops.h>
39#include <linux/string.h>
40#include <linux/slab.h>
41#include <linux/falloc.h>
42#include <asm/uaccess.h>
43#include <linux/fiemap.h>
44#include "ext4_jbd2.h"
45#include "ext4_extents.h"
46
47#include <trace/events/ext4.h>
48
49static int ext4_split_extent(handle_t *handle,
50 struct inode *inode,
51 struct ext4_ext_path *path,
52 struct ext4_map_blocks *map,
53 int split_flag,
54 int flags);
55
56static int ext4_ext_truncate_extend_restart(handle_t *handle,
57 struct inode *inode,
58 int needed)
59{
60 int err;
61
62 if (!ext4_handle_valid(handle))
63 return 0;
64 if (handle->h_buffer_credits > needed)
65 return 0;
66 err = ext4_journal_extend(handle, needed);
67 if (err <= 0)
68 return err;
69 err = ext4_truncate_restart_trans(handle, inode, needed);
70 if (err == 0)
71 err = -EAGAIN;
72
73 return err;
74}
75
76/*
77 * could return:
78 * - EROFS
79 * - ENOMEM
80 */
81static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
82 struct ext4_ext_path *path)
83{
84 if (path->p_bh) {
85 /* path points to block */
86 return ext4_journal_get_write_access(handle, path->p_bh);
87 }
88 /* path points to leaf/index in inode body */
89 /* we use in-core data, no need to protect them */
90 return 0;
91}
92
93/*
94 * could return:
95 * - EROFS
96 * - ENOMEM
97 * - EIO
98 */
99static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
100 struct ext4_ext_path *path)
101{
102 int err;
103 if (path->p_bh) {
104 /* path points to block */
105 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
106 } else {
107 /* path points to leaf/index in inode body */
108 err = ext4_mark_inode_dirty(handle, inode);
109 }
110 return err;
111}
112
113static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
114 struct ext4_ext_path *path,
115 ext4_lblk_t block)
116{
117 int depth;
118
119 if (path) {
120 struct ext4_extent *ex;
121 depth = path->p_depth;
122
123 /*
124 * Try to predict block placement assuming that we are
125 * filling in a file which will eventually be
126 * non-sparse --- i.e., in the case of libbfd writing
127 * an ELF object sections out-of-order but in a way
128 * the eventually results in a contiguous object or
129 * executable file, or some database extending a table
130 * space file. However, this is actually somewhat
131 * non-ideal if we are writing a sparse file such as
132 * qemu or KVM writing a raw image file that is going
133 * to stay fairly sparse, since it will end up
134 * fragmenting the file system's free space. Maybe we
135 * should have some hueristics or some way to allow
136 * userspace to pass a hint to file system,
137 * especially if the latter case turns out to be
138 * common.
139 */
140 ex = path[depth].p_ext;
141 if (ex) {
142 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
143 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
144
145 if (block > ext_block)
146 return ext_pblk + (block - ext_block);
147 else
148 return ext_pblk - (ext_block - block);
149 }
150
151 /* it looks like index is empty;
152 * try to find starting block from index itself */
153 if (path[depth].p_bh)
154 return path[depth].p_bh->b_blocknr;
155 }
156
157 /* OK. use inode's group */
158 return ext4_inode_to_goal_block(inode);
159}
160
161/*
162 * Allocation for a meta data block
163 */
164static ext4_fsblk_t
165ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
166 struct ext4_ext_path *path,
167 struct ext4_extent *ex, int *err, unsigned int flags)
168{
169 ext4_fsblk_t goal, newblock;
170
171 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
172 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
173 NULL, err);
174 return newblock;
175}
176
177static inline int ext4_ext_space_block(struct inode *inode, int check)
178{
179 int size;
180
181 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
182 / sizeof(struct ext4_extent);
183 if (!check) {
184#ifdef AGGRESSIVE_TEST
185 if (size > 6)
186 size = 6;
187#endif
188 }
189 return size;
190}
191
192static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
193{
194 int size;
195
196 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
197 / sizeof(struct ext4_extent_idx);
198 if (!check) {
199#ifdef AGGRESSIVE_TEST
200 if (size > 5)
201 size = 5;
202#endif
203 }
204 return size;
205}
206
207static inline int ext4_ext_space_root(struct inode *inode, int check)
208{
209 int size;
210
211 size = sizeof(EXT4_I(inode)->i_data);
212 size -= sizeof(struct ext4_extent_header);
213 size /= sizeof(struct ext4_extent);
214 if (!check) {
215#ifdef AGGRESSIVE_TEST
216 if (size > 3)
217 size = 3;
218#endif
219 }
220 return size;
221}
222
223static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
224{
225 int size;
226
227 size = sizeof(EXT4_I(inode)->i_data);
228 size -= sizeof(struct ext4_extent_header);
229 size /= sizeof(struct ext4_extent_idx);
230 if (!check) {
231#ifdef AGGRESSIVE_TEST
232 if (size > 4)
233 size = 4;
234#endif
235 }
236 return size;
237}
238
239/*
240 * Calculate the number of metadata blocks needed
241 * to allocate @blocks
242 * Worse case is one block per extent
243 */
244int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
245{
246 struct ext4_inode_info *ei = EXT4_I(inode);
247 int idxs, num = 0;
248
249 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
250 / sizeof(struct ext4_extent_idx));
251
252 /*
253 * If the new delayed allocation block is contiguous with the
254 * previous da block, it can share index blocks with the
255 * previous block, so we only need to allocate a new index
256 * block every idxs leaf blocks. At ldxs**2 blocks, we need
257 * an additional index block, and at ldxs**3 blocks, yet
258 * another index blocks.
259 */
260 if (ei->i_da_metadata_calc_len &&
261 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
262 if ((ei->i_da_metadata_calc_len % idxs) == 0)
263 num++;
264 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
265 num++;
266 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
267 num++;
268 ei->i_da_metadata_calc_len = 0;
269 } else
270 ei->i_da_metadata_calc_len++;
271 ei->i_da_metadata_calc_last_lblock++;
272 return num;
273 }
274
275 /*
276 * In the worst case we need a new set of index blocks at
277 * every level of the inode's extent tree.
278 */
279 ei->i_da_metadata_calc_len = 1;
280 ei->i_da_metadata_calc_last_lblock = lblock;
281 return ext_depth(inode) + 1;
282}
283
284static int
285ext4_ext_max_entries(struct inode *inode, int depth)
286{
287 int max;
288
289 if (depth == ext_depth(inode)) {
290 if (depth == 0)
291 max = ext4_ext_space_root(inode, 1);
292 else
293 max = ext4_ext_space_root_idx(inode, 1);
294 } else {
295 if (depth == 0)
296 max = ext4_ext_space_block(inode, 1);
297 else
298 max = ext4_ext_space_block_idx(inode, 1);
299 }
300
301 return max;
302}
303
304static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
305{
306 ext4_fsblk_t block = ext4_ext_pblock(ext);
307 int len = ext4_ext_get_actual_len(ext);
308
309 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
310}
311
312static int ext4_valid_extent_idx(struct inode *inode,
313 struct ext4_extent_idx *ext_idx)
314{
315 ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
316
317 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
318}
319
320static int ext4_valid_extent_entries(struct inode *inode,
321 struct ext4_extent_header *eh,
322 int depth)
323{
324 struct ext4_extent *ext;
325 struct ext4_extent_idx *ext_idx;
326 unsigned short entries;
327 if (eh->eh_entries == 0)
328 return 1;
329
330 entries = le16_to_cpu(eh->eh_entries);
331
332 if (depth == 0) {
333 /* leaf entries */
334 ext = EXT_FIRST_EXTENT(eh);
335 while (entries) {
336 if (!ext4_valid_extent(inode, ext))
337 return 0;
338 ext++;
339 entries--;
340 }
341 } else {
342 ext_idx = EXT_FIRST_INDEX(eh);
343 while (entries) {
344 if (!ext4_valid_extent_idx(inode, ext_idx))
345 return 0;
346 ext_idx++;
347 entries--;
348 }
349 }
350 return 1;
351}
352
353static int __ext4_ext_check(const char *function, unsigned int line,
354 struct inode *inode, struct ext4_extent_header *eh,
355 int depth)
356{
357 const char *error_msg;
358 int max = 0;
359
360 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
361 error_msg = "invalid magic";
362 goto corrupted;
363 }
364 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
365 error_msg = "unexpected eh_depth";
366 goto corrupted;
367 }
368 if (unlikely(eh->eh_max == 0)) {
369 error_msg = "invalid eh_max";
370 goto corrupted;
371 }
372 max = ext4_ext_max_entries(inode, depth);
373 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
374 error_msg = "too large eh_max";
375 goto corrupted;
376 }
377 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
378 error_msg = "invalid eh_entries";
379 goto corrupted;
380 }
381 if (!ext4_valid_extent_entries(inode, eh, depth)) {
382 error_msg = "invalid extent entries";
383 goto corrupted;
384 }
385 return 0;
386
387corrupted:
388 ext4_error_inode(inode, function, line, 0,
389 "bad header/extent: %s - magic %x, "
390 "entries %u, max %u(%u), depth %u(%u)",
391 error_msg, le16_to_cpu(eh->eh_magic),
392 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
393 max, le16_to_cpu(eh->eh_depth), depth);
394
395 return -EIO;
396}
397
398#define ext4_ext_check(inode, eh, depth) \
399 __ext4_ext_check(__func__, __LINE__, inode, eh, depth)
400
401int ext4_ext_check_inode(struct inode *inode)
402{
403 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
404}
405
406#ifdef EXT_DEBUG
407static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
408{
409 int k, l = path->p_depth;
410
411 ext_debug("path:");
412 for (k = 0; k <= l; k++, path++) {
413 if (path->p_idx) {
414 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
415 ext4_idx_pblock(path->p_idx));
416 } else if (path->p_ext) {
417 ext_debug(" %d:[%d]%d:%llu ",
418 le32_to_cpu(path->p_ext->ee_block),
419 ext4_ext_is_uninitialized(path->p_ext),
420 ext4_ext_get_actual_len(path->p_ext),
421 ext4_ext_pblock(path->p_ext));
422 } else
423 ext_debug(" []");
424 }
425 ext_debug("\n");
426}
427
428static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
429{
430 int depth = ext_depth(inode);
431 struct ext4_extent_header *eh;
432 struct ext4_extent *ex;
433 int i;
434
435 if (!path)
436 return;
437
438 eh = path[depth].p_hdr;
439 ex = EXT_FIRST_EXTENT(eh);
440
441 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
442
443 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
444 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
445 ext4_ext_is_uninitialized(ex),
446 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
447 }
448 ext_debug("\n");
449}
450
451static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
452 ext4_fsblk_t newblock, int level)
453{
454 int depth = ext_depth(inode);
455 struct ext4_extent *ex;
456
457 if (depth != level) {
458 struct ext4_extent_idx *idx;
459 idx = path[level].p_idx;
460 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
461 ext_debug("%d: move %d:%llu in new index %llu\n", level,
462 le32_to_cpu(idx->ei_block),
463 ext4_idx_pblock(idx),
464 newblock);
465 idx++;
466 }
467
468 return;
469 }
470
471 ex = path[depth].p_ext;
472 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
473 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
474 le32_to_cpu(ex->ee_block),
475 ext4_ext_pblock(ex),
476 ext4_ext_is_uninitialized(ex),
477 ext4_ext_get_actual_len(ex),
478 newblock);
479 ex++;
480 }
481}
482
483#else
484#define ext4_ext_show_path(inode, path)
485#define ext4_ext_show_leaf(inode, path)
486#define ext4_ext_show_move(inode, path, newblock, level)
487#endif
488
489void ext4_ext_drop_refs(struct ext4_ext_path *path)
490{
491 int depth = path->p_depth;
492 int i;
493
494 for (i = 0; i <= depth; i++, path++)
495 if (path->p_bh) {
496 brelse(path->p_bh);
497 path->p_bh = NULL;
498 }
499}
500
501/*
502 * ext4_ext_binsearch_idx:
503 * binary search for the closest index of the given block
504 * the header must be checked before calling this
505 */
506static void
507ext4_ext_binsearch_idx(struct inode *inode,
508 struct ext4_ext_path *path, ext4_lblk_t block)
509{
510 struct ext4_extent_header *eh = path->p_hdr;
511 struct ext4_extent_idx *r, *l, *m;
512
513
514 ext_debug("binsearch for %u(idx): ", block);
515
516 l = EXT_FIRST_INDEX(eh) + 1;
517 r = EXT_LAST_INDEX(eh);
518 while (l <= r) {
519 m = l + (r - l) / 2;
520 if (block < le32_to_cpu(m->ei_block))
521 r = m - 1;
522 else
523 l = m + 1;
524 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
525 m, le32_to_cpu(m->ei_block),
526 r, le32_to_cpu(r->ei_block));
527 }
528
529 path->p_idx = l - 1;
530 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
531 ext4_idx_pblock(path->p_idx));
532
533#ifdef CHECK_BINSEARCH
534 {
535 struct ext4_extent_idx *chix, *ix;
536 int k;
537
538 chix = ix = EXT_FIRST_INDEX(eh);
539 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
540 if (k != 0 &&
541 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
542 printk(KERN_DEBUG "k=%d, ix=0x%p, "
543 "first=0x%p\n", k,
544 ix, EXT_FIRST_INDEX(eh));
545 printk(KERN_DEBUG "%u <= %u\n",
546 le32_to_cpu(ix->ei_block),
547 le32_to_cpu(ix[-1].ei_block));
548 }
549 BUG_ON(k && le32_to_cpu(ix->ei_block)
550 <= le32_to_cpu(ix[-1].ei_block));
551 if (block < le32_to_cpu(ix->ei_block))
552 break;
553 chix = ix;
554 }
555 BUG_ON(chix != path->p_idx);
556 }
557#endif
558
559}
560
561/*
562 * ext4_ext_binsearch:
563 * binary search for closest extent of the given block
564 * the header must be checked before calling this
565 */
566static void
567ext4_ext_binsearch(struct inode *inode,
568 struct ext4_ext_path *path, ext4_lblk_t block)
569{
570 struct ext4_extent_header *eh = path->p_hdr;
571 struct ext4_extent *r, *l, *m;
572
573 if (eh->eh_entries == 0) {
574 /*
575 * this leaf is empty:
576 * we get such a leaf in split/add case
577 */
578 return;
579 }
580
581 ext_debug("binsearch for %u: ", block);
582
583 l = EXT_FIRST_EXTENT(eh) + 1;
584 r = EXT_LAST_EXTENT(eh);
585
586 while (l <= r) {
587 m = l + (r - l) / 2;
588 if (block < le32_to_cpu(m->ee_block))
589 r = m - 1;
590 else
591 l = m + 1;
592 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
593 m, le32_to_cpu(m->ee_block),
594 r, le32_to_cpu(r->ee_block));
595 }
596
597 path->p_ext = l - 1;
598 ext_debug(" -> %d:%llu:[%d]%d ",
599 le32_to_cpu(path->p_ext->ee_block),
600 ext4_ext_pblock(path->p_ext),
601 ext4_ext_is_uninitialized(path->p_ext),
602 ext4_ext_get_actual_len(path->p_ext));
603
604#ifdef CHECK_BINSEARCH
605 {
606 struct ext4_extent *chex, *ex;
607 int k;
608
609 chex = ex = EXT_FIRST_EXTENT(eh);
610 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
611 BUG_ON(k && le32_to_cpu(ex->ee_block)
612 <= le32_to_cpu(ex[-1].ee_block));
613 if (block < le32_to_cpu(ex->ee_block))
614 break;
615 chex = ex;
616 }
617 BUG_ON(chex != path->p_ext);
618 }
619#endif
620
621}
622
623int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
624{
625 struct ext4_extent_header *eh;
626
627 eh = ext_inode_hdr(inode);
628 eh->eh_depth = 0;
629 eh->eh_entries = 0;
630 eh->eh_magic = EXT4_EXT_MAGIC;
631 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
632 ext4_mark_inode_dirty(handle, inode);
633 ext4_ext_invalidate_cache(inode);
634 return 0;
635}
636
637struct ext4_ext_path *
638ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
639 struct ext4_ext_path *path)
640{
641 struct ext4_extent_header *eh;
642 struct buffer_head *bh;
643 short int depth, i, ppos = 0, alloc = 0;
644
645 eh = ext_inode_hdr(inode);
646 depth = ext_depth(inode);
647
648 /* account possible depth increase */
649 if (!path) {
650 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
651 GFP_NOFS);
652 if (!path)
653 return ERR_PTR(-ENOMEM);
654 alloc = 1;
655 }
656 path[0].p_hdr = eh;
657 path[0].p_bh = NULL;
658
659 i = depth;
660 /* walk through the tree */
661 while (i) {
662 int need_to_validate = 0;
663
664 ext_debug("depth %d: num %d, max %d\n",
665 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
666
667 ext4_ext_binsearch_idx(inode, path + ppos, block);
668 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
669 path[ppos].p_depth = i;
670 path[ppos].p_ext = NULL;
671
672 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
673 if (unlikely(!bh))
674 goto err;
675 if (!bh_uptodate_or_lock(bh)) {
676 trace_ext4_ext_load_extent(inode, block,
677 path[ppos].p_block);
678 if (bh_submit_read(bh) < 0) {
679 put_bh(bh);
680 goto err;
681 }
682 /* validate the extent entries */
683 need_to_validate = 1;
684 }
685 eh = ext_block_hdr(bh);
686 ppos++;
687 if (unlikely(ppos > depth)) {
688 put_bh(bh);
689 EXT4_ERROR_INODE(inode,
690 "ppos %d > depth %d", ppos, depth);
691 goto err;
692 }
693 path[ppos].p_bh = bh;
694 path[ppos].p_hdr = eh;
695 i--;
696
697 if (need_to_validate && ext4_ext_check(inode, eh, i))
698 goto err;
699 }
700
701 path[ppos].p_depth = i;
702 path[ppos].p_ext = NULL;
703 path[ppos].p_idx = NULL;
704
705 /* find extent */
706 ext4_ext_binsearch(inode, path + ppos, block);
707 /* if not an empty leaf */
708 if (path[ppos].p_ext)
709 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
710
711 ext4_ext_show_path(inode, path);
712
713 return path;
714
715err:
716 ext4_ext_drop_refs(path);
717 if (alloc)
718 kfree(path);
719 return ERR_PTR(-EIO);
720}
721
722/*
723 * ext4_ext_insert_index:
724 * insert new index [@logical;@ptr] into the block at @curp;
725 * check where to insert: before @curp or after @curp
726 */
727static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
728 struct ext4_ext_path *curp,
729 int logical, ext4_fsblk_t ptr)
730{
731 struct ext4_extent_idx *ix;
732 int len, err;
733
734 err = ext4_ext_get_access(handle, inode, curp);
735 if (err)
736 return err;
737
738 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
739 EXT4_ERROR_INODE(inode,
740 "logical %d == ei_block %d!",
741 logical, le32_to_cpu(curp->p_idx->ei_block));
742 return -EIO;
743 }
744
745 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
746 >= le16_to_cpu(curp->p_hdr->eh_max))) {
747 EXT4_ERROR_INODE(inode,
748 "eh_entries %d >= eh_max %d!",
749 le16_to_cpu(curp->p_hdr->eh_entries),
750 le16_to_cpu(curp->p_hdr->eh_max));
751 return -EIO;
752 }
753
754 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
755 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
756 /* insert after */
757 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
758 len = (len - 1) * sizeof(struct ext4_extent_idx);
759 len = len < 0 ? 0 : len;
760 ext_debug("insert new index %d after: %llu. "
761 "move %d from 0x%p to 0x%p\n",
762 logical, ptr, len,
763 (curp->p_idx + 1), (curp->p_idx + 2));
764 memmove(curp->p_idx + 2, curp->p_idx + 1, len);
765 }
766 ix = curp->p_idx + 1;
767 } else {
768 /* insert before */
769 len = len * sizeof(struct ext4_extent_idx);
770 len = len < 0 ? 0 : len;
771 ext_debug("insert new index %d before: %llu. "
772 "move %d from 0x%p to 0x%p\n",
773 logical, ptr, len,
774 curp->p_idx, (curp->p_idx + 1));
775 memmove(curp->p_idx + 1, curp->p_idx, len);
776 ix = curp->p_idx;
777 }
778
779 ix->ei_block = cpu_to_le32(logical);
780 ext4_idx_store_pblock(ix, ptr);
781 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
782
783 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
784 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
785 return -EIO;
786 }
787
788 err = ext4_ext_dirty(handle, inode, curp);
789 ext4_std_error(inode->i_sb, err);
790
791 return err;
792}
793
794/*
795 * ext4_ext_split:
796 * inserts new subtree into the path, using free index entry
797 * at depth @at:
798 * - allocates all needed blocks (new leaf and all intermediate index blocks)
799 * - makes decision where to split
800 * - moves remaining extents and index entries (right to the split point)
801 * into the newly allocated blocks
802 * - initializes subtree
803 */
804static int ext4_ext_split(handle_t *handle, struct inode *inode,
805 unsigned int flags,
806 struct ext4_ext_path *path,
807 struct ext4_extent *newext, int at)
808{
809 struct buffer_head *bh = NULL;
810 int depth = ext_depth(inode);
811 struct ext4_extent_header *neh;
812 struct ext4_extent_idx *fidx;
813 int i = at, k, m, a;
814 ext4_fsblk_t newblock, oldblock;
815 __le32 border;
816 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
817 int err = 0;
818
819 /* make decision: where to split? */
820 /* FIXME: now decision is simplest: at current extent */
821
822 /* if current leaf will be split, then we should use
823 * border from split point */
824 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
825 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
826 return -EIO;
827 }
828 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
829 border = path[depth].p_ext[1].ee_block;
830 ext_debug("leaf will be split."
831 " next leaf starts at %d\n",
832 le32_to_cpu(border));
833 } else {
834 border = newext->ee_block;
835 ext_debug("leaf will be added."
836 " next leaf starts at %d\n",
837 le32_to_cpu(border));
838 }
839
840 /*
841 * If error occurs, then we break processing
842 * and mark filesystem read-only. index won't
843 * be inserted and tree will be in consistent
844 * state. Next mount will repair buffers too.
845 */
846
847 /*
848 * Get array to track all allocated blocks.
849 * We need this to handle errors and free blocks
850 * upon them.
851 */
852 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
853 if (!ablocks)
854 return -ENOMEM;
855
856 /* allocate all needed blocks */
857 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
858 for (a = 0; a < depth - at; a++) {
859 newblock = ext4_ext_new_meta_block(handle, inode, path,
860 newext, &err, flags);
861 if (newblock == 0)
862 goto cleanup;
863 ablocks[a] = newblock;
864 }
865
866 /* initialize new leaf */
867 newblock = ablocks[--a];
868 if (unlikely(newblock == 0)) {
869 EXT4_ERROR_INODE(inode, "newblock == 0!");
870 err = -EIO;
871 goto cleanup;
872 }
873 bh = sb_getblk(inode->i_sb, newblock);
874 if (!bh) {
875 err = -EIO;
876 goto cleanup;
877 }
878 lock_buffer(bh);
879
880 err = ext4_journal_get_create_access(handle, bh);
881 if (err)
882 goto cleanup;
883
884 neh = ext_block_hdr(bh);
885 neh->eh_entries = 0;
886 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
887 neh->eh_magic = EXT4_EXT_MAGIC;
888 neh->eh_depth = 0;
889
890 /* move remainder of path[depth] to the new leaf */
891 if (unlikely(path[depth].p_hdr->eh_entries !=
892 path[depth].p_hdr->eh_max)) {
893 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
894 path[depth].p_hdr->eh_entries,
895 path[depth].p_hdr->eh_max);
896 err = -EIO;
897 goto cleanup;
898 }
899 /* start copy from next extent */
900 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
901 ext4_ext_show_move(inode, path, newblock, depth);
902 if (m) {
903 struct ext4_extent *ex;
904 ex = EXT_FIRST_EXTENT(neh);
905 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
906 le16_add_cpu(&neh->eh_entries, m);
907 }
908
909 set_buffer_uptodate(bh);
910 unlock_buffer(bh);
911
912 err = ext4_handle_dirty_metadata(handle, inode, bh);
913 if (err)
914 goto cleanup;
915 brelse(bh);
916 bh = NULL;
917
918 /* correct old leaf */
919 if (m) {
920 err = ext4_ext_get_access(handle, inode, path + depth);
921 if (err)
922 goto cleanup;
923 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
924 err = ext4_ext_dirty(handle, inode, path + depth);
925 if (err)
926 goto cleanup;
927
928 }
929
930 /* create intermediate indexes */
931 k = depth - at - 1;
932 if (unlikely(k < 0)) {
933 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
934 err = -EIO;
935 goto cleanup;
936 }
937 if (k)
938 ext_debug("create %d intermediate indices\n", k);
939 /* insert new index into current index block */
940 /* current depth stored in i var */
941 i = depth - 1;
942 while (k--) {
943 oldblock = newblock;
944 newblock = ablocks[--a];
945 bh = sb_getblk(inode->i_sb, newblock);
946 if (!bh) {
947 err = -EIO;
948 goto cleanup;
949 }
950 lock_buffer(bh);
951
952 err = ext4_journal_get_create_access(handle, bh);
953 if (err)
954 goto cleanup;
955
956 neh = ext_block_hdr(bh);
957 neh->eh_entries = cpu_to_le16(1);
958 neh->eh_magic = EXT4_EXT_MAGIC;
959 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
960 neh->eh_depth = cpu_to_le16(depth - i);
961 fidx = EXT_FIRST_INDEX(neh);
962 fidx->ei_block = border;
963 ext4_idx_store_pblock(fidx, oldblock);
964
965 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
966 i, newblock, le32_to_cpu(border), oldblock);
967
968 /* move remainder of path[i] to the new index block */
969 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
970 EXT_LAST_INDEX(path[i].p_hdr))) {
971 EXT4_ERROR_INODE(inode,
972 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
973 le32_to_cpu(path[i].p_ext->ee_block));
974 err = -EIO;
975 goto cleanup;
976 }
977 /* start copy indexes */
978 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
979 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
980 EXT_MAX_INDEX(path[i].p_hdr));
981 ext4_ext_show_move(inode, path, newblock, i);
982 if (m) {
983 memmove(++fidx, path[i].p_idx,
984 sizeof(struct ext4_extent_idx) * m);
985 le16_add_cpu(&neh->eh_entries, m);
986 }
987 set_buffer_uptodate(bh);
988 unlock_buffer(bh);
989
990 err = ext4_handle_dirty_metadata(handle, inode, bh);
991 if (err)
992 goto cleanup;
993 brelse(bh);
994 bh = NULL;
995
996 /* correct old index */
997 if (m) {
998 err = ext4_ext_get_access(handle, inode, path + i);
999 if (err)
1000 goto cleanup;
1001 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1002 err = ext4_ext_dirty(handle, inode, path + i);
1003 if (err)
1004 goto cleanup;
1005 }
1006
1007 i--;
1008 }
1009
1010 /* insert new index */
1011 err = ext4_ext_insert_index(handle, inode, path + at,
1012 le32_to_cpu(border), newblock);
1013
1014cleanup:
1015 if (bh) {
1016 if (buffer_locked(bh))
1017 unlock_buffer(bh);
1018 brelse(bh);
1019 }
1020
1021 if (err) {
1022 /* free all allocated blocks in error case */
1023 for (i = 0; i < depth; i++) {
1024 if (!ablocks[i])
1025 continue;
1026 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1027 EXT4_FREE_BLOCKS_METADATA);
1028 }
1029 }
1030 kfree(ablocks);
1031
1032 return err;
1033}
1034
1035/*
1036 * ext4_ext_grow_indepth:
1037 * implements tree growing procedure:
1038 * - allocates new block
1039 * - moves top-level data (index block or leaf) into the new block
1040 * - initializes new top-level, creating index that points to the
1041 * just created block
1042 */
1043static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1044 unsigned int flags,
1045 struct ext4_ext_path *path,
1046 struct ext4_extent *newext)
1047{
1048 struct ext4_ext_path *curp = path;
1049 struct ext4_extent_header *neh;
1050 struct buffer_head *bh;
1051 ext4_fsblk_t newblock;
1052 int err = 0;
1053
1054 newblock = ext4_ext_new_meta_block(handle, inode, path,
1055 newext, &err, flags);
1056 if (newblock == 0)
1057 return err;
1058
1059 bh = sb_getblk(inode->i_sb, newblock);
1060 if (!bh) {
1061 err = -EIO;
1062 ext4_std_error(inode->i_sb, err);
1063 return err;
1064 }
1065 lock_buffer(bh);
1066
1067 err = ext4_journal_get_create_access(handle, bh);
1068 if (err) {
1069 unlock_buffer(bh);
1070 goto out;
1071 }
1072
1073 /* move top-level index/leaf into new block */
1074 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
1075
1076 /* set size of new block */
1077 neh = ext_block_hdr(bh);
1078 /* old root could have indexes or leaves
1079 * so calculate e_max right way */
1080 if (ext_depth(inode))
1081 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1082 else
1083 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1084 neh->eh_magic = EXT4_EXT_MAGIC;
1085 set_buffer_uptodate(bh);
1086 unlock_buffer(bh);
1087
1088 err = ext4_handle_dirty_metadata(handle, inode, bh);
1089 if (err)
1090 goto out;
1091
1092 /* create index in new top-level index: num,max,pointer */
1093 err = ext4_ext_get_access(handle, inode, curp);
1094 if (err)
1095 goto out;
1096
1097 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
1098 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1099 curp->p_hdr->eh_entries = cpu_to_le16(1);
1100 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
1101
1102 if (path[0].p_hdr->eh_depth)
1103 curp->p_idx->ei_block =
1104 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
1105 else
1106 curp->p_idx->ei_block =
1107 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
1108 ext4_idx_store_pblock(curp->p_idx, newblock);
1109
1110 neh = ext_inode_hdr(inode);
1111 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1112 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1113 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1114 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1115
1116 neh->eh_depth = cpu_to_le16(path->p_depth + 1);
1117 err = ext4_ext_dirty(handle, inode, curp);
1118out:
1119 brelse(bh);
1120
1121 return err;
1122}
1123
1124/*
1125 * ext4_ext_create_new_leaf:
1126 * finds empty index and adds new leaf.
1127 * if no free index is found, then it requests in-depth growing.
1128 */
1129static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1130 unsigned int flags,
1131 struct ext4_ext_path *path,
1132 struct ext4_extent *newext)
1133{
1134 struct ext4_ext_path *curp;
1135 int depth, i, err = 0;
1136
1137repeat:
1138 i = depth = ext_depth(inode);
1139
1140 /* walk up to the tree and look for free index entry */
1141 curp = path + depth;
1142 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1143 i--;
1144 curp--;
1145 }
1146
1147 /* we use already allocated block for index block,
1148 * so subsequent data blocks should be contiguous */
1149 if (EXT_HAS_FREE_INDEX(curp)) {
1150 /* if we found index with free entry, then use that
1151 * entry: create all needed subtree and add new leaf */
1152 err = ext4_ext_split(handle, inode, flags, path, newext, i);
1153 if (err)
1154 goto out;
1155
1156 /* refill path */
1157 ext4_ext_drop_refs(path);
1158 path = ext4_ext_find_extent(inode,
1159 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1160 path);
1161 if (IS_ERR(path))
1162 err = PTR_ERR(path);
1163 } else {
1164 /* tree is full, time to grow in depth */
1165 err = ext4_ext_grow_indepth(handle, inode, flags,
1166 path, newext);
1167 if (err)
1168 goto out;
1169
1170 /* refill path */
1171 ext4_ext_drop_refs(path);
1172 path = ext4_ext_find_extent(inode,
1173 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1174 path);
1175 if (IS_ERR(path)) {
1176 err = PTR_ERR(path);
1177 goto out;
1178 }
1179
1180 /*
1181 * only first (depth 0 -> 1) produces free space;
1182 * in all other cases we have to split the grown tree
1183 */
1184 depth = ext_depth(inode);
1185 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1186 /* now we need to split */
1187 goto repeat;
1188 }
1189 }
1190
1191out:
1192 return err;
1193}
1194
1195/*
1196 * search the closest allocated block to the left for *logical
1197 * and returns it at @logical + it's physical address at @phys
1198 * if *logical is the smallest allocated block, the function
1199 * returns 0 at @phys
1200 * return value contains 0 (success) or error code
1201 */
1202static int ext4_ext_search_left(struct inode *inode,
1203 struct ext4_ext_path *path,
1204 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1205{
1206 struct ext4_extent_idx *ix;
1207 struct ext4_extent *ex;
1208 int depth, ee_len;
1209
1210 if (unlikely(path == NULL)) {
1211 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1212 return -EIO;
1213 }
1214 depth = path->p_depth;
1215 *phys = 0;
1216
1217 if (depth == 0 && path->p_ext == NULL)
1218 return 0;
1219
1220 /* usually extent in the path covers blocks smaller
1221 * then *logical, but it can be that extent is the
1222 * first one in the file */
1223
1224 ex = path[depth].p_ext;
1225 ee_len = ext4_ext_get_actual_len(ex);
1226 if (*logical < le32_to_cpu(ex->ee_block)) {
1227 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1228 EXT4_ERROR_INODE(inode,
1229 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1230 *logical, le32_to_cpu(ex->ee_block));
1231 return -EIO;
1232 }
1233 while (--depth >= 0) {
1234 ix = path[depth].p_idx;
1235 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1236 EXT4_ERROR_INODE(inode,
1237 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1238 ix != NULL ? ix->ei_block : 0,
1239 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1240 EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0,
1241 depth);
1242 return -EIO;
1243 }
1244 }
1245 return 0;
1246 }
1247
1248 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1249 EXT4_ERROR_INODE(inode,
1250 "logical %d < ee_block %d + ee_len %d!",
1251 *logical, le32_to_cpu(ex->ee_block), ee_len);
1252 return -EIO;
1253 }
1254
1255 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1256 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1257 return 0;
1258}
1259
1260/*
1261 * search the closest allocated block to the right for *logical
1262 * and returns it at @logical + it's physical address at @phys
1263 * if *logical is the smallest allocated block, the function
1264 * returns 0 at @phys
1265 * return value contains 0 (success) or error code
1266 */
1267static int ext4_ext_search_right(struct inode *inode,
1268 struct ext4_ext_path *path,
1269 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1270{
1271 struct buffer_head *bh = NULL;
1272 struct ext4_extent_header *eh;
1273 struct ext4_extent_idx *ix;
1274 struct ext4_extent *ex;
1275 ext4_fsblk_t block;
1276 int depth; /* Note, NOT eh_depth; depth from top of tree */
1277 int ee_len;
1278
1279 if (unlikely(path == NULL)) {
1280 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1281 return -EIO;
1282 }
1283 depth = path->p_depth;
1284 *phys = 0;
1285
1286 if (depth == 0 && path->p_ext == NULL)
1287 return 0;
1288
1289 /* usually extent in the path covers blocks smaller
1290 * then *logical, but it can be that extent is the
1291 * first one in the file */
1292
1293 ex = path[depth].p_ext;
1294 ee_len = ext4_ext_get_actual_len(ex);
1295 if (*logical < le32_to_cpu(ex->ee_block)) {
1296 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1297 EXT4_ERROR_INODE(inode,
1298 "first_extent(path[%d].p_hdr) != ex",
1299 depth);
1300 return -EIO;
1301 }
1302 while (--depth >= 0) {
1303 ix = path[depth].p_idx;
1304 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1305 EXT4_ERROR_INODE(inode,
1306 "ix != EXT_FIRST_INDEX *logical %d!",
1307 *logical);
1308 return -EIO;
1309 }
1310 }
1311 *logical = le32_to_cpu(ex->ee_block);
1312 *phys = ext4_ext_pblock(ex);
1313 return 0;
1314 }
1315
1316 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1317 EXT4_ERROR_INODE(inode,
1318 "logical %d < ee_block %d + ee_len %d!",
1319 *logical, le32_to_cpu(ex->ee_block), ee_len);
1320 return -EIO;
1321 }
1322
1323 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1324 /* next allocated block in this leaf */
1325 ex++;
1326 *logical = le32_to_cpu(ex->ee_block);
1327 *phys = ext4_ext_pblock(ex);
1328 return 0;
1329 }
1330
1331 /* go up and search for index to the right */
1332 while (--depth >= 0) {
1333 ix = path[depth].p_idx;
1334 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1335 goto got_index;
1336 }
1337
1338 /* we've gone up to the root and found no index to the right */
1339 return 0;
1340
1341got_index:
1342 /* we've found index to the right, let's
1343 * follow it and find the closest allocated
1344 * block to the right */
1345 ix++;
1346 block = ext4_idx_pblock(ix);
1347 while (++depth < path->p_depth) {
1348 bh = sb_bread(inode->i_sb, block);
1349 if (bh == NULL)
1350 return -EIO;
1351 eh = ext_block_hdr(bh);
1352 /* subtract from p_depth to get proper eh_depth */
1353 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1354 put_bh(bh);
1355 return -EIO;
1356 }
1357 ix = EXT_FIRST_INDEX(eh);
1358 block = ext4_idx_pblock(ix);
1359 put_bh(bh);
1360 }
1361
1362 bh = sb_bread(inode->i_sb, block);
1363 if (bh == NULL)
1364 return -EIO;
1365 eh = ext_block_hdr(bh);
1366 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1367 put_bh(bh);
1368 return -EIO;
1369 }
1370 ex = EXT_FIRST_EXTENT(eh);
1371 *logical = le32_to_cpu(ex->ee_block);
1372 *phys = ext4_ext_pblock(ex);
1373 put_bh(bh);
1374 return 0;
1375}
1376
1377/*
1378 * ext4_ext_next_allocated_block:
1379 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1380 * NOTE: it considers block number from index entry as
1381 * allocated block. Thus, index entries have to be consistent
1382 * with leaves.
1383 */
1384static ext4_lblk_t
1385ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1386{
1387 int depth;
1388
1389 BUG_ON(path == NULL);
1390 depth = path->p_depth;
1391
1392 if (depth == 0 && path->p_ext == NULL)
1393 return EXT_MAX_BLOCKS;
1394
1395 while (depth >= 0) {
1396 if (depth == path->p_depth) {
1397 /* leaf */
1398 if (path[depth].p_ext !=
1399 EXT_LAST_EXTENT(path[depth].p_hdr))
1400 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1401 } else {
1402 /* index */
1403 if (path[depth].p_idx !=
1404 EXT_LAST_INDEX(path[depth].p_hdr))
1405 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1406 }
1407 depth--;
1408 }
1409
1410 return EXT_MAX_BLOCKS;
1411}
1412
1413/*
1414 * ext4_ext_next_leaf_block:
1415 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1416 */
1417static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1418{
1419 int depth;
1420
1421 BUG_ON(path == NULL);
1422 depth = path->p_depth;
1423
1424 /* zero-tree has no leaf blocks at all */
1425 if (depth == 0)
1426 return EXT_MAX_BLOCKS;
1427
1428 /* go to index block */
1429 depth--;
1430
1431 while (depth >= 0) {
1432 if (path[depth].p_idx !=
1433 EXT_LAST_INDEX(path[depth].p_hdr))
1434 return (ext4_lblk_t)
1435 le32_to_cpu(path[depth].p_idx[1].ei_block);
1436 depth--;
1437 }
1438
1439 return EXT_MAX_BLOCKS;
1440}
1441
1442/*
1443 * ext4_ext_correct_indexes:
1444 * if leaf gets modified and modified extent is first in the leaf,
1445 * then we have to correct all indexes above.
1446 * TODO: do we need to correct tree in all cases?
1447 */
1448static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1449 struct ext4_ext_path *path)
1450{
1451 struct ext4_extent_header *eh;
1452 int depth = ext_depth(inode);
1453 struct ext4_extent *ex;
1454 __le32 border;
1455 int k, err = 0;
1456
1457 eh = path[depth].p_hdr;
1458 ex = path[depth].p_ext;
1459
1460 if (unlikely(ex == NULL || eh == NULL)) {
1461 EXT4_ERROR_INODE(inode,
1462 "ex %p == NULL or eh %p == NULL", ex, eh);
1463 return -EIO;
1464 }
1465
1466 if (depth == 0) {
1467 /* there is no tree at all */
1468 return 0;
1469 }
1470
1471 if (ex != EXT_FIRST_EXTENT(eh)) {
1472 /* we correct tree if first leaf got modified only */
1473 return 0;
1474 }
1475
1476 /*
1477 * TODO: we need correction if border is smaller than current one
1478 */
1479 k = depth - 1;
1480 border = path[depth].p_ext->ee_block;
1481 err = ext4_ext_get_access(handle, inode, path + k);
1482 if (err)
1483 return err;
1484 path[k].p_idx->ei_block = border;
1485 err = ext4_ext_dirty(handle, inode, path + k);
1486 if (err)
1487 return err;
1488
1489 while (k--) {
1490 /* change all left-side indexes */
1491 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1492 break;
1493 err = ext4_ext_get_access(handle, inode, path + k);
1494 if (err)
1495 break;
1496 path[k].p_idx->ei_block = border;
1497 err = ext4_ext_dirty(handle, inode, path + k);
1498 if (err)
1499 break;
1500 }
1501
1502 return err;
1503}
1504
1505int
1506ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1507 struct ext4_extent *ex2)
1508{
1509 unsigned short ext1_ee_len, ext2_ee_len, max_len;
1510
1511 /*
1512 * Make sure that either both extents are uninitialized, or
1513 * both are _not_.
1514 */
1515 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1516 return 0;
1517
1518 if (ext4_ext_is_uninitialized(ex1))
1519 max_len = EXT_UNINIT_MAX_LEN;
1520 else
1521 max_len = EXT_INIT_MAX_LEN;
1522
1523 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1524 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1525
1526 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1527 le32_to_cpu(ex2->ee_block))
1528 return 0;
1529
1530 /*
1531 * To allow future support for preallocated extents to be added
1532 * as an RO_COMPAT feature, refuse to merge to extents if
1533 * this can result in the top bit of ee_len being set.
1534 */
1535 if (ext1_ee_len + ext2_ee_len > max_len)
1536 return 0;
1537#ifdef AGGRESSIVE_TEST
1538 if (ext1_ee_len >= 4)
1539 return 0;
1540#endif
1541
1542 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1543 return 1;
1544 return 0;
1545}
1546
1547/*
1548 * This function tries to merge the "ex" extent to the next extent in the tree.
1549 * It always tries to merge towards right. If you want to merge towards
1550 * left, pass "ex - 1" as argument instead of "ex".
1551 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1552 * 1 if they got merged.
1553 */
1554static int ext4_ext_try_to_merge_right(struct inode *inode,
1555 struct ext4_ext_path *path,
1556 struct ext4_extent *ex)
1557{
1558 struct ext4_extent_header *eh;
1559 unsigned int depth, len;
1560 int merge_done = 0;
1561 int uninitialized = 0;
1562
1563 depth = ext_depth(inode);
1564 BUG_ON(path[depth].p_hdr == NULL);
1565 eh = path[depth].p_hdr;
1566
1567 while (ex < EXT_LAST_EXTENT(eh)) {
1568 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1569 break;
1570 /* merge with next extent! */
1571 if (ext4_ext_is_uninitialized(ex))
1572 uninitialized = 1;
1573 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1574 + ext4_ext_get_actual_len(ex + 1));
1575 if (uninitialized)
1576 ext4_ext_mark_uninitialized(ex);
1577
1578 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1579 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1580 * sizeof(struct ext4_extent);
1581 memmove(ex + 1, ex + 2, len);
1582 }
1583 le16_add_cpu(&eh->eh_entries, -1);
1584 merge_done = 1;
1585 WARN_ON(eh->eh_entries == 0);
1586 if (!eh->eh_entries)
1587 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1588 }
1589
1590 return merge_done;
1591}
1592
1593/*
1594 * This function tries to merge the @ex extent to neighbours in the tree.
1595 * return 1 if merge left else 0.
1596 */
1597static int ext4_ext_try_to_merge(struct inode *inode,
1598 struct ext4_ext_path *path,
1599 struct ext4_extent *ex) {
1600 struct ext4_extent_header *eh;
1601 unsigned int depth;
1602 int merge_done = 0;
1603 int ret = 0;
1604
1605 depth = ext_depth(inode);
1606 BUG_ON(path[depth].p_hdr == NULL);
1607 eh = path[depth].p_hdr;
1608
1609 if (ex > EXT_FIRST_EXTENT(eh))
1610 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1611
1612 if (!merge_done)
1613 ret = ext4_ext_try_to_merge_right(inode, path, ex);
1614
1615 return ret;
1616}
1617
1618/*
1619 * check if a portion of the "newext" extent overlaps with an
1620 * existing extent.
1621 *
1622 * If there is an overlap discovered, it updates the length of the newext
1623 * such that there will be no overlap, and then returns 1.
1624 * If there is no overlap found, it returns 0.
1625 */
1626static unsigned int ext4_ext_check_overlap(struct inode *inode,
1627 struct ext4_extent *newext,
1628 struct ext4_ext_path *path)
1629{
1630 ext4_lblk_t b1, b2;
1631 unsigned int depth, len1;
1632 unsigned int ret = 0;
1633
1634 b1 = le32_to_cpu(newext->ee_block);
1635 len1 = ext4_ext_get_actual_len(newext);
1636 depth = ext_depth(inode);
1637 if (!path[depth].p_ext)
1638 goto out;
1639 b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1640
1641 /*
1642 * get the next allocated block if the extent in the path
1643 * is before the requested block(s)
1644 */
1645 if (b2 < b1) {
1646 b2 = ext4_ext_next_allocated_block(path);
1647 if (b2 == EXT_MAX_BLOCKS)
1648 goto out;
1649 }
1650
1651 /* check for wrap through zero on extent logical start block*/
1652 if (b1 + len1 < b1) {
1653 len1 = EXT_MAX_BLOCKS - b1;
1654 newext->ee_len = cpu_to_le16(len1);
1655 ret = 1;
1656 }
1657
1658 /* check for overlap */
1659 if (b1 + len1 > b2) {
1660 newext->ee_len = cpu_to_le16(b2 - b1);
1661 ret = 1;
1662 }
1663out:
1664 return ret;
1665}
1666
1667/*
1668 * ext4_ext_insert_extent:
1669 * tries to merge requsted extent into the existing extent or
1670 * inserts requested extent as new one into the tree,
1671 * creating new leaf in the no-space case.
1672 */
1673int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1674 struct ext4_ext_path *path,
1675 struct ext4_extent *newext, int flag)
1676{
1677 struct ext4_extent_header *eh;
1678 struct ext4_extent *ex, *fex;
1679 struct ext4_extent *nearex; /* nearest extent */
1680 struct ext4_ext_path *npath = NULL;
1681 int depth, len, err;
1682 ext4_lblk_t next;
1683 unsigned uninitialized = 0;
1684 int flags = 0;
1685
1686 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1687 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1688 return -EIO;
1689 }
1690 depth = ext_depth(inode);
1691 ex = path[depth].p_ext;
1692 if (unlikely(path[depth].p_hdr == NULL)) {
1693 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1694 return -EIO;
1695 }
1696
1697 /* try to insert block into found extent and return */
1698 if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
1699 && ext4_can_extents_be_merged(inode, ex, newext)) {
1700 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
1701 ext4_ext_is_uninitialized(newext),
1702 ext4_ext_get_actual_len(newext),
1703 le32_to_cpu(ex->ee_block),
1704 ext4_ext_is_uninitialized(ex),
1705 ext4_ext_get_actual_len(ex),
1706 ext4_ext_pblock(ex));
1707 err = ext4_ext_get_access(handle, inode, path + depth);
1708 if (err)
1709 return err;
1710
1711 /*
1712 * ext4_can_extents_be_merged should have checked that either
1713 * both extents are uninitialized, or both aren't. Thus we
1714 * need to check only one of them here.
1715 */
1716 if (ext4_ext_is_uninitialized(ex))
1717 uninitialized = 1;
1718 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1719 + ext4_ext_get_actual_len(newext));
1720 if (uninitialized)
1721 ext4_ext_mark_uninitialized(ex);
1722 eh = path[depth].p_hdr;
1723 nearex = ex;
1724 goto merge;
1725 }
1726
1727 depth = ext_depth(inode);
1728 eh = path[depth].p_hdr;
1729 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1730 goto has_space;
1731
1732 /* probably next leaf has space for us? */
1733 fex = EXT_LAST_EXTENT(eh);
1734 next = EXT_MAX_BLOCKS;
1735 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1736 next = ext4_ext_next_leaf_block(path);
1737 if (next != EXT_MAX_BLOCKS) {
1738 ext_debug("next leaf block - %d\n", next);
1739 BUG_ON(npath != NULL);
1740 npath = ext4_ext_find_extent(inode, next, NULL);
1741 if (IS_ERR(npath))
1742 return PTR_ERR(npath);
1743 BUG_ON(npath->p_depth != path->p_depth);
1744 eh = npath[depth].p_hdr;
1745 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1746 ext_debug("next leaf isn't full(%d)\n",
1747 le16_to_cpu(eh->eh_entries));
1748 path = npath;
1749 goto has_space;
1750 }
1751 ext_debug("next leaf has no free space(%d,%d)\n",
1752 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1753 }
1754
1755 /*
1756 * There is no free space in the found leaf.
1757 * We're gonna add a new leaf in the tree.
1758 */
1759 if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
1760 flags = EXT4_MB_USE_ROOT_BLOCKS;
1761 err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
1762 if (err)
1763 goto cleanup;
1764 depth = ext_depth(inode);
1765 eh = path[depth].p_hdr;
1766
1767has_space:
1768 nearex = path[depth].p_ext;
1769
1770 err = ext4_ext_get_access(handle, inode, path + depth);
1771 if (err)
1772 goto cleanup;
1773
1774 if (!nearex) {
1775 /* there is no extent in this leaf, create first one */
1776 ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n",
1777 le32_to_cpu(newext->ee_block),
1778 ext4_ext_pblock(newext),
1779 ext4_ext_is_uninitialized(newext),
1780 ext4_ext_get_actual_len(newext));
1781 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1782 } else if (le32_to_cpu(newext->ee_block)
1783 > le32_to_cpu(nearex->ee_block)) {
1784/* BUG_ON(newext->ee_block == nearex->ee_block); */
1785 if (nearex != EXT_LAST_EXTENT(eh)) {
1786 len = EXT_MAX_EXTENT(eh) - nearex;
1787 len = (len - 1) * sizeof(struct ext4_extent);
1788 len = len < 0 ? 0 : len;
1789 ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, "
1790 "move %d from 0x%p to 0x%p\n",
1791 le32_to_cpu(newext->ee_block),
1792 ext4_ext_pblock(newext),
1793 ext4_ext_is_uninitialized(newext),
1794 ext4_ext_get_actual_len(newext),
1795 nearex, len, nearex + 1, nearex + 2);
1796 memmove(nearex + 2, nearex + 1, len);
1797 }
1798 path[depth].p_ext = nearex + 1;
1799 } else {
1800 BUG_ON(newext->ee_block == nearex->ee_block);
1801 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1802 len = len < 0 ? 0 : len;
1803 ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, "
1804 "move %d from 0x%p to 0x%p\n",
1805 le32_to_cpu(newext->ee_block),
1806 ext4_ext_pblock(newext),
1807 ext4_ext_is_uninitialized(newext),
1808 ext4_ext_get_actual_len(newext),
1809 nearex, len, nearex, nearex + 1);
1810 memmove(nearex + 1, nearex, len);
1811 path[depth].p_ext = nearex;
1812 }
1813
1814 le16_add_cpu(&eh->eh_entries, 1);
1815 nearex = path[depth].p_ext;
1816 nearex->ee_block = newext->ee_block;
1817 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
1818 nearex->ee_len = newext->ee_len;
1819
1820merge:
1821 /* try to merge extents to the right */
1822 if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
1823 ext4_ext_try_to_merge(inode, path, nearex);
1824
1825 /* try to merge extents to the left */
1826
1827 /* time to correct all indexes above */
1828 err = ext4_ext_correct_indexes(handle, inode, path);
1829 if (err)
1830 goto cleanup;
1831
1832 err = ext4_ext_dirty(handle, inode, path + depth);
1833
1834cleanup:
1835 if (npath) {
1836 ext4_ext_drop_refs(npath);
1837 kfree(npath);
1838 }
1839 ext4_ext_invalidate_cache(inode);
1840 return err;
1841}
1842
1843static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1844 ext4_lblk_t num, ext_prepare_callback func,
1845 void *cbdata)
1846{
1847 struct ext4_ext_path *path = NULL;
1848 struct ext4_ext_cache cbex;
1849 struct ext4_extent *ex;
1850 ext4_lblk_t next, start = 0, end = 0;
1851 ext4_lblk_t last = block + num;
1852 int depth, exists, err = 0;
1853
1854 BUG_ON(func == NULL);
1855 BUG_ON(inode == NULL);
1856
1857 while (block < last && block != EXT_MAX_BLOCKS) {
1858 num = last - block;
1859 /* find extent for this block */
1860 down_read(&EXT4_I(inode)->i_data_sem);
1861 path = ext4_ext_find_extent(inode, block, path);
1862 up_read(&EXT4_I(inode)->i_data_sem);
1863 if (IS_ERR(path)) {
1864 err = PTR_ERR(path);
1865 path = NULL;
1866 break;
1867 }
1868
1869 depth = ext_depth(inode);
1870 if (unlikely(path[depth].p_hdr == NULL)) {
1871 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1872 err = -EIO;
1873 break;
1874 }
1875 ex = path[depth].p_ext;
1876 next = ext4_ext_next_allocated_block(path);
1877
1878 exists = 0;
1879 if (!ex) {
1880 /* there is no extent yet, so try to allocate
1881 * all requested space */
1882 start = block;
1883 end = block + num;
1884 } else if (le32_to_cpu(ex->ee_block) > block) {
1885 /* need to allocate space before found extent */
1886 start = block;
1887 end = le32_to_cpu(ex->ee_block);
1888 if (block + num < end)
1889 end = block + num;
1890 } else if (block >= le32_to_cpu(ex->ee_block)
1891 + ext4_ext_get_actual_len(ex)) {
1892 /* need to allocate space after found extent */
1893 start = block;
1894 end = block + num;
1895 if (end >= next)
1896 end = next;
1897 } else if (block >= le32_to_cpu(ex->ee_block)) {
1898 /*
1899 * some part of requested space is covered
1900 * by found extent
1901 */
1902 start = block;
1903 end = le32_to_cpu(ex->ee_block)
1904 + ext4_ext_get_actual_len(ex);
1905 if (block + num < end)
1906 end = block + num;
1907 exists = 1;
1908 } else {
1909 BUG();
1910 }
1911 BUG_ON(end <= start);
1912
1913 if (!exists) {
1914 cbex.ec_block = start;
1915 cbex.ec_len = end - start;
1916 cbex.ec_start = 0;
1917 } else {
1918 cbex.ec_block = le32_to_cpu(ex->ee_block);
1919 cbex.ec_len = ext4_ext_get_actual_len(ex);
1920 cbex.ec_start = ext4_ext_pblock(ex);
1921 }
1922
1923 if (unlikely(cbex.ec_len == 0)) {
1924 EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
1925 err = -EIO;
1926 break;
1927 }
1928 err = func(inode, next, &cbex, ex, cbdata);
1929 ext4_ext_drop_refs(path);
1930
1931 if (err < 0)
1932 break;
1933
1934 if (err == EXT_REPEAT)
1935 continue;
1936 else if (err == EXT_BREAK) {
1937 err = 0;
1938 break;
1939 }
1940
1941 if (ext_depth(inode) != depth) {
1942 /* depth was changed. we have to realloc path */
1943 kfree(path);
1944 path = NULL;
1945 }
1946
1947 block = cbex.ec_block + cbex.ec_len;
1948 }
1949
1950 if (path) {
1951 ext4_ext_drop_refs(path);
1952 kfree(path);
1953 }
1954
1955 return err;
1956}
1957
1958static void
1959ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1960 __u32 len, ext4_fsblk_t start)
1961{
1962 struct ext4_ext_cache *cex;
1963 BUG_ON(len == 0);
1964 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1965 cex = &EXT4_I(inode)->i_cached_extent;
1966 cex->ec_block = block;
1967 cex->ec_len = len;
1968 cex->ec_start = start;
1969 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1970}
1971
1972/*
1973 * ext4_ext_put_gap_in_cache:
1974 * calculate boundaries of the gap that the requested block fits into
1975 * and cache this gap
1976 */
1977static void
1978ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1979 ext4_lblk_t block)
1980{
1981 int depth = ext_depth(inode);
1982 unsigned long len;
1983 ext4_lblk_t lblock;
1984 struct ext4_extent *ex;
1985
1986 ex = path[depth].p_ext;
1987 if (ex == NULL) {
1988 /* there is no extent yet, so gap is [0;-] */
1989 lblock = 0;
1990 len = EXT_MAX_BLOCKS;
1991 ext_debug("cache gap(whole file):");
1992 } else if (block < le32_to_cpu(ex->ee_block)) {
1993 lblock = block;
1994 len = le32_to_cpu(ex->ee_block) - block;
1995 ext_debug("cache gap(before): %u [%u:%u]",
1996 block,
1997 le32_to_cpu(ex->ee_block),
1998 ext4_ext_get_actual_len(ex));
1999 } else if (block >= le32_to_cpu(ex->ee_block)
2000 + ext4_ext_get_actual_len(ex)) {
2001 ext4_lblk_t next;
2002 lblock = le32_to_cpu(ex->ee_block)
2003 + ext4_ext_get_actual_len(ex);
2004
2005 next = ext4_ext_next_allocated_block(path);
2006 ext_debug("cache gap(after): [%u:%u] %u",
2007 le32_to_cpu(ex->ee_block),
2008 ext4_ext_get_actual_len(ex),
2009 block);
2010 BUG_ON(next == lblock);
2011 len = next - lblock;
2012 } else {
2013 lblock = len = 0;
2014 BUG();
2015 }
2016
2017 ext_debug(" -> %u:%lu\n", lblock, len);
2018 ext4_ext_put_in_cache(inode, lblock, len, 0);
2019}
2020
2021/*
2022 * ext4_ext_check_cache()
2023 * Checks to see if the given block is in the cache.
2024 * If it is, the cached extent is stored in the given
2025 * cache extent pointer. If the cached extent is a hole,
2026 * this routine should be used instead of
2027 * ext4_ext_in_cache if the calling function needs to
2028 * know the size of the hole.
2029 *
2030 * @inode: The files inode
2031 * @block: The block to look for in the cache
2032 * @ex: Pointer where the cached extent will be stored
2033 * if it contains block
2034 *
2035 * Return 0 if cache is invalid; 1 if the cache is valid
2036 */
2037static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block,
2038 struct ext4_ext_cache *ex){
2039 struct ext4_ext_cache *cex;
2040 struct ext4_sb_info *sbi;
2041 int ret = 0;
2042
2043 /*
2044 * We borrow i_block_reservation_lock to protect i_cached_extent
2045 */
2046 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
2047 cex = &EXT4_I(inode)->i_cached_extent;
2048 sbi = EXT4_SB(inode->i_sb);
2049
2050 /* has cache valid data? */
2051 if (cex->ec_len == 0)
2052 goto errout;
2053
2054 if (in_range(block, cex->ec_block, cex->ec_len)) {
2055 memcpy(ex, cex, sizeof(struct ext4_ext_cache));
2056 ext_debug("%u cached by %u:%u:%llu\n",
2057 block,
2058 cex->ec_block, cex->ec_len, cex->ec_start);
2059 ret = 1;
2060 }
2061errout:
2062 if (!ret)
2063 sbi->extent_cache_misses++;
2064 else
2065 sbi->extent_cache_hits++;
2066 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
2067 return ret;
2068}
2069
2070/*
2071 * ext4_ext_in_cache()
2072 * Checks to see if the given block is in the cache.
2073 * If it is, the cached extent is stored in the given
2074 * extent pointer.
2075 *
2076 * @inode: The files inode
2077 * @block: The block to look for in the cache
2078 * @ex: Pointer where the cached extent will be stored
2079 * if it contains block
2080 *
2081 * Return 0 if cache is invalid; 1 if the cache is valid
2082 */
2083static int
2084ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
2085 struct ext4_extent *ex)
2086{
2087 struct ext4_ext_cache cex;
2088 int ret = 0;
2089
2090 if (ext4_ext_check_cache(inode, block, &cex)) {
2091 ex->ee_block = cpu_to_le32(cex.ec_block);
2092 ext4_ext_store_pblock(ex, cex.ec_start);
2093 ex->ee_len = cpu_to_le16(cex.ec_len);
2094 ret = 1;
2095 }
2096
2097 return ret;
2098}
2099
2100
2101/*
2102 * ext4_ext_rm_idx:
2103 * removes index from the index block.
2104 */
2105static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2106 struct ext4_ext_path *path)
2107{
2108 int err;
2109 ext4_fsblk_t leaf;
2110
2111 /* free index block */
2112 path--;
2113 leaf = ext4_idx_pblock(path->p_idx);
2114 if (unlikely(path->p_hdr->eh_entries == 0)) {
2115 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2116 return -EIO;
2117 }
2118 err = ext4_ext_get_access(handle, inode, path);
2119 if (err)
2120 return err;
2121
2122 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2123 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2124 len *= sizeof(struct ext4_extent_idx);
2125 memmove(path->p_idx, path->p_idx + 1, len);
2126 }
2127
2128 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2129 err = ext4_ext_dirty(handle, inode, path);
2130 if (err)
2131 return err;
2132 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2133 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2134 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2135 return err;
2136}
2137
2138/*
2139 * ext4_ext_calc_credits_for_single_extent:
2140 * This routine returns max. credits that needed to insert an extent
2141 * to the extent tree.
2142 * When pass the actual path, the caller should calculate credits
2143 * under i_data_sem.
2144 */
2145int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2146 struct ext4_ext_path *path)
2147{
2148 if (path) {
2149 int depth = ext_depth(inode);
2150 int ret = 0;
2151
2152 /* probably there is space in leaf? */
2153 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2154 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2155
2156 /*
2157 * There are some space in the leaf tree, no
2158 * need to account for leaf block credit
2159 *
2160 * bitmaps and block group descriptor blocks
2161 * and other metadat blocks still need to be
2162 * accounted.
2163 */
2164 /* 1 bitmap, 1 block group descriptor */
2165 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2166 return ret;
2167 }
2168 }
2169
2170 return ext4_chunk_trans_blocks(inode, nrblocks);
2171}
2172
2173/*
2174 * How many index/leaf blocks need to change/allocate to modify nrblocks?
2175 *
2176 * if nrblocks are fit in a single extent (chunk flag is 1), then
2177 * in the worse case, each tree level index/leaf need to be changed
2178 * if the tree split due to insert a new extent, then the old tree
2179 * index/leaf need to be updated too
2180 *
2181 * If the nrblocks are discontiguous, they could cause
2182 * the whole tree split more than once, but this is really rare.
2183 */
2184int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2185{
2186 int index;
2187 int depth = ext_depth(inode);
2188
2189 if (chunk)
2190 index = depth * 2;
2191 else
2192 index = depth * 3;
2193
2194 return index;
2195}
2196
2197static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2198 struct ext4_extent *ex,
2199 ext4_lblk_t from, ext4_lblk_t to)
2200{
2201 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2202 int flags = EXT4_FREE_BLOCKS_FORGET;
2203
2204 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2205 flags |= EXT4_FREE_BLOCKS_METADATA;
2206#ifdef EXTENTS_STATS
2207 {
2208 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2209 spin_lock(&sbi->s_ext_stats_lock);
2210 sbi->s_ext_blocks += ee_len;
2211 sbi->s_ext_extents++;
2212 if (ee_len < sbi->s_ext_min)
2213 sbi->s_ext_min = ee_len;
2214 if (ee_len > sbi->s_ext_max)
2215 sbi->s_ext_max = ee_len;
2216 if (ext_depth(inode) > sbi->s_depth_max)
2217 sbi->s_depth_max = ext_depth(inode);
2218 spin_unlock(&sbi->s_ext_stats_lock);
2219 }
2220#endif
2221 if (from >= le32_to_cpu(ex->ee_block)
2222 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2223 /* tail removal */
2224 ext4_lblk_t num;
2225 ext4_fsblk_t start;
2226
2227 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2228 start = ext4_ext_pblock(ex) + ee_len - num;
2229 ext_debug("free last %u blocks starting %llu\n", num, start);
2230 ext4_free_blocks(handle, inode, NULL, start, num, flags);
2231 } else if (from == le32_to_cpu(ex->ee_block)
2232 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2233 /* head removal */
2234 ext4_lblk_t num;
2235 ext4_fsblk_t start;
2236
2237 num = to - from;
2238 start = ext4_ext_pblock(ex);
2239
2240 ext_debug("free first %u blocks starting %llu\n", num, start);
2241 ext4_free_blocks(handle, inode, 0, start, num, flags);
2242
2243 } else {
2244 printk(KERN_INFO "strange request: removal(2) "
2245 "%u-%u from %u:%u\n",
2246 from, to, le32_to_cpu(ex->ee_block), ee_len);
2247 }
2248 return 0;
2249}
2250
2251
2252/*
2253 * ext4_ext_rm_leaf() Removes the extents associated with the
2254 * blocks appearing between "start" and "end", and splits the extents
2255 * if "start" and "end" appear in the same extent
2256 *
2257 * @handle: The journal handle
2258 * @inode: The files inode
2259 * @path: The path to the leaf
2260 * @start: The first block to remove
2261 * @end: The last block to remove
2262 */
2263static int
2264ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2265 struct ext4_ext_path *path, ext4_lblk_t start,
2266 ext4_lblk_t end)
2267{
2268 int err = 0, correct_index = 0;
2269 int depth = ext_depth(inode), credits;
2270 struct ext4_extent_header *eh;
2271 ext4_lblk_t a, b, block;
2272 unsigned num;
2273 ext4_lblk_t ex_ee_block;
2274 unsigned short ex_ee_len;
2275 unsigned uninitialized = 0;
2276 struct ext4_extent *ex;
2277 struct ext4_map_blocks map;
2278
2279 /* the header must be checked already in ext4_ext_remove_space() */
2280 ext_debug("truncate since %u in leaf\n", start);
2281 if (!path[depth].p_hdr)
2282 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2283 eh = path[depth].p_hdr;
2284 if (unlikely(path[depth].p_hdr == NULL)) {
2285 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2286 return -EIO;
2287 }
2288 /* find where to start removing */
2289 ex = EXT_LAST_EXTENT(eh);
2290
2291 ex_ee_block = le32_to_cpu(ex->ee_block);
2292 ex_ee_len = ext4_ext_get_actual_len(ex);
2293
2294 while (ex >= EXT_FIRST_EXTENT(eh) &&
2295 ex_ee_block + ex_ee_len > start) {
2296
2297 if (ext4_ext_is_uninitialized(ex))
2298 uninitialized = 1;
2299 else
2300 uninitialized = 0;
2301
2302 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2303 uninitialized, ex_ee_len);
2304 path[depth].p_ext = ex;
2305
2306 a = ex_ee_block > start ? ex_ee_block : start;
2307 b = ex_ee_block+ex_ee_len - 1 < end ?
2308 ex_ee_block+ex_ee_len - 1 : end;
2309
2310 ext_debug(" border %u:%u\n", a, b);
2311
2312 /* If this extent is beyond the end of the hole, skip it */
2313 if (end <= ex_ee_block) {
2314 ex--;
2315 ex_ee_block = le32_to_cpu(ex->ee_block);
2316 ex_ee_len = ext4_ext_get_actual_len(ex);
2317 continue;
2318 } else if (a != ex_ee_block &&
2319 b != ex_ee_block + ex_ee_len - 1) {
2320 /*
2321 * If this is a truncate, then this condition should
2322 * never happen because at least one of the end points
2323 * needs to be on the edge of the extent.
2324 */
2325 if (end == EXT_MAX_BLOCKS - 1) {
2326 ext_debug(" bad truncate %u:%u\n",
2327 start, end);
2328 block = 0;
2329 num = 0;
2330 err = -EIO;
2331 goto out;
2332 }
2333 /*
2334 * else this is a hole punch, so the extent needs to
2335 * be split since neither edge of the hole is on the
2336 * extent edge
2337 */
2338 else{
2339 map.m_pblk = ext4_ext_pblock(ex);
2340 map.m_lblk = ex_ee_block;
2341 map.m_len = b - ex_ee_block;
2342
2343 err = ext4_split_extent(handle,
2344 inode, path, &map, 0,
2345 EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
2346 EXT4_GET_BLOCKS_PRE_IO);
2347
2348 if (err < 0)
2349 goto out;
2350
2351 ex_ee_len = ext4_ext_get_actual_len(ex);
2352
2353 b = ex_ee_block+ex_ee_len - 1 < end ?
2354 ex_ee_block+ex_ee_len - 1 : end;
2355
2356 /* Then remove tail of this extent */
2357 block = ex_ee_block;
2358 num = a - block;
2359 }
2360 } else if (a != ex_ee_block) {
2361 /* remove tail of the extent */
2362 block = ex_ee_block;
2363 num = a - block;
2364 } else if (b != ex_ee_block + ex_ee_len - 1) {
2365 /* remove head of the extent */
2366 block = b;
2367 num = ex_ee_block + ex_ee_len - b;
2368
2369 /*
2370 * If this is a truncate, this condition
2371 * should never happen
2372 */
2373 if (end == EXT_MAX_BLOCKS - 1) {
2374 ext_debug(" bad truncate %u:%u\n",
2375 start, end);
2376 err = -EIO;
2377 goto out;
2378 }
2379 } else {
2380 /* remove whole extent: excellent! */
2381 block = ex_ee_block;
2382 num = 0;
2383 if (a != ex_ee_block) {
2384 ext_debug(" bad truncate %u:%u\n",
2385 start, end);
2386 err = -EIO;
2387 goto out;
2388 }
2389
2390 if (b != ex_ee_block + ex_ee_len - 1) {
2391 ext_debug(" bad truncate %u:%u\n",
2392 start, end);
2393 err = -EIO;
2394 goto out;
2395 }
2396 }
2397
2398 /*
2399 * 3 for leaf, sb, and inode plus 2 (bmap and group
2400 * descriptor) for each block group; assume two block
2401 * groups plus ex_ee_len/blocks_per_block_group for
2402 * the worst case
2403 */
2404 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2405 if (ex == EXT_FIRST_EXTENT(eh)) {
2406 correct_index = 1;
2407 credits += (ext_depth(inode)) + 1;
2408 }
2409 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2410
2411 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2412 if (err)
2413 goto out;
2414
2415 err = ext4_ext_get_access(handle, inode, path + depth);
2416 if (err)
2417 goto out;
2418
2419 err = ext4_remove_blocks(handle, inode, ex, a, b);
2420 if (err)
2421 goto out;
2422
2423 if (num == 0) {
2424 /* this extent is removed; mark slot entirely unused */
2425 ext4_ext_store_pblock(ex, 0);
2426 } else if (block != ex_ee_block) {
2427 /*
2428 * If this was a head removal, then we need to update
2429 * the physical block since it is now at a different
2430 * location
2431 */
2432 ext4_ext_store_pblock(ex, ext4_ext_pblock(ex) + (b-a));
2433 }
2434
2435 ex->ee_block = cpu_to_le32(block);
2436 ex->ee_len = cpu_to_le16(num);
2437 /*
2438 * Do not mark uninitialized if all the blocks in the
2439 * extent have been removed.
2440 */
2441 if (uninitialized && num)
2442 ext4_ext_mark_uninitialized(ex);
2443
2444 err = ext4_ext_dirty(handle, inode, path + depth);
2445 if (err)
2446 goto out;
2447
2448 /*
2449 * If the extent was completely released,
2450 * we need to remove it from the leaf
2451 */
2452 if (num == 0) {
2453 if (end != EXT_MAX_BLOCKS - 1) {
2454 /*
2455 * For hole punching, we need to scoot all the
2456 * extents up when an extent is removed so that
2457 * we dont have blank extents in the middle
2458 */
2459 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2460 sizeof(struct ext4_extent));
2461
2462 /* Now get rid of the one at the end */
2463 memset(EXT_LAST_EXTENT(eh), 0,
2464 sizeof(struct ext4_extent));
2465 }
2466 le16_add_cpu(&eh->eh_entries, -1);
2467 }
2468
2469 ext_debug("new extent: %u:%u:%llu\n", block, num,
2470 ext4_ext_pblock(ex));
2471 ex--;
2472 ex_ee_block = le32_to_cpu(ex->ee_block);
2473 ex_ee_len = ext4_ext_get_actual_len(ex);
2474 }
2475
2476 if (correct_index && eh->eh_entries)
2477 err = ext4_ext_correct_indexes(handle, inode, path);
2478
2479 /* if this leaf is free, then we should
2480 * remove it from index block above */
2481 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2482 err = ext4_ext_rm_idx(handle, inode, path + depth);
2483
2484out:
2485 return err;
2486}
2487
2488/*
2489 * ext4_ext_more_to_rm:
2490 * returns 1 if current index has to be freed (even partial)
2491 */
2492static int
2493ext4_ext_more_to_rm(struct ext4_ext_path *path)
2494{
2495 BUG_ON(path->p_idx == NULL);
2496
2497 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2498 return 0;
2499
2500 /*
2501 * if truncate on deeper level happened, it wasn't partial,
2502 * so we have to consider current index for truncation
2503 */
2504 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2505 return 0;
2506 return 1;
2507}
2508
2509static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
2510{
2511 struct super_block *sb = inode->i_sb;
2512 int depth = ext_depth(inode);
2513 struct ext4_ext_path *path;
2514 handle_t *handle;
2515 int i, err;
2516
2517 ext_debug("truncate since %u\n", start);
2518
2519 /* probably first extent we're gonna free will be last in block */
2520 handle = ext4_journal_start(inode, depth + 1);
2521 if (IS_ERR(handle))
2522 return PTR_ERR(handle);
2523
2524again:
2525 ext4_ext_invalidate_cache(inode);
2526
2527 /*
2528 * We start scanning from right side, freeing all the blocks
2529 * after i_size and walking into the tree depth-wise.
2530 */
2531 depth = ext_depth(inode);
2532 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
2533 if (path == NULL) {
2534 ext4_journal_stop(handle);
2535 return -ENOMEM;
2536 }
2537 path[0].p_depth = depth;
2538 path[0].p_hdr = ext_inode_hdr(inode);
2539 if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2540 err = -EIO;
2541 goto out;
2542 }
2543 i = err = 0;
2544
2545 while (i >= 0 && err == 0) {
2546 if (i == depth) {
2547 /* this is leaf block */
2548 err = ext4_ext_rm_leaf(handle, inode, path,
2549 start, EXT_MAX_BLOCKS - 1);
2550 /* root level has p_bh == NULL, brelse() eats this */
2551 brelse(path[i].p_bh);
2552 path[i].p_bh = NULL;
2553 i--;
2554 continue;
2555 }
2556
2557 /* this is index block */
2558 if (!path[i].p_hdr) {
2559 ext_debug("initialize header\n");
2560 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2561 }
2562
2563 if (!path[i].p_idx) {
2564 /* this level hasn't been touched yet */
2565 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2566 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2567 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2568 path[i].p_hdr,
2569 le16_to_cpu(path[i].p_hdr->eh_entries));
2570 } else {
2571 /* we were already here, see at next index */
2572 path[i].p_idx--;
2573 }
2574
2575 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2576 i, EXT_FIRST_INDEX(path[i].p_hdr),
2577 path[i].p_idx);
2578 if (ext4_ext_more_to_rm(path + i)) {
2579 struct buffer_head *bh;
2580 /* go to the next level */
2581 ext_debug("move to level %d (block %llu)\n",
2582 i + 1, ext4_idx_pblock(path[i].p_idx));
2583 memset(path + i + 1, 0, sizeof(*path));
2584 bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
2585 if (!bh) {
2586 /* should we reset i_size? */
2587 err = -EIO;
2588 break;
2589 }
2590 if (WARN_ON(i + 1 > depth)) {
2591 err = -EIO;
2592 break;
2593 }
2594 if (ext4_ext_check(inode, ext_block_hdr(bh),
2595 depth - i - 1)) {
2596 err = -EIO;
2597 break;
2598 }
2599 path[i + 1].p_bh = bh;
2600
2601 /* save actual number of indexes since this
2602 * number is changed at the next iteration */
2603 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2604 i++;
2605 } else {
2606 /* we finished processing this index, go up */
2607 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2608 /* index is empty, remove it;
2609 * handle must be already prepared by the
2610 * truncatei_leaf() */
2611 err = ext4_ext_rm_idx(handle, inode, path + i);
2612 }
2613 /* root level has p_bh == NULL, brelse() eats this */
2614 brelse(path[i].p_bh);
2615 path[i].p_bh = NULL;
2616 i--;
2617 ext_debug("return to level %d\n", i);
2618 }
2619 }
2620
2621 /* TODO: flexible tree reduction should be here */
2622 if (path->p_hdr->eh_entries == 0) {
2623 /*
2624 * truncate to zero freed all the tree,
2625 * so we need to correct eh_depth
2626 */
2627 err = ext4_ext_get_access(handle, inode, path);
2628 if (err == 0) {
2629 ext_inode_hdr(inode)->eh_depth = 0;
2630 ext_inode_hdr(inode)->eh_max =
2631 cpu_to_le16(ext4_ext_space_root(inode, 0));
2632 err = ext4_ext_dirty(handle, inode, path);
2633 }
2634 }
2635out:
2636 ext4_ext_drop_refs(path);
2637 kfree(path);
2638 if (err == -EAGAIN)
2639 goto again;
2640 ext4_journal_stop(handle);
2641
2642 return err;
2643}
2644
2645/*
2646 * called at mount time
2647 */
2648void ext4_ext_init(struct super_block *sb)
2649{
2650 /*
2651 * possible initialization would be here
2652 */
2653
2654 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2655#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
2656 printk(KERN_INFO "EXT4-fs: file extents enabled");
2657#ifdef AGGRESSIVE_TEST
2658 printk(", aggressive tests");
2659#endif
2660#ifdef CHECK_BINSEARCH
2661 printk(", check binsearch");
2662#endif
2663#ifdef EXTENTS_STATS
2664 printk(", stats");
2665#endif
2666 printk("\n");
2667#endif
2668#ifdef EXTENTS_STATS
2669 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2670 EXT4_SB(sb)->s_ext_min = 1 << 30;
2671 EXT4_SB(sb)->s_ext_max = 0;
2672#endif
2673 }
2674}
2675
2676/*
2677 * called at umount time
2678 */
2679void ext4_ext_release(struct super_block *sb)
2680{
2681 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2682 return;
2683
2684#ifdef EXTENTS_STATS
2685 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2686 struct ext4_sb_info *sbi = EXT4_SB(sb);
2687 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2688 sbi->s_ext_blocks, sbi->s_ext_extents,
2689 sbi->s_ext_blocks / sbi->s_ext_extents);
2690 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2691 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2692 }
2693#endif
2694}
2695
2696/* FIXME!! we need to try to merge to left or right after zero-out */
2697static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2698{
2699 ext4_fsblk_t ee_pblock;
2700 unsigned int ee_len;
2701 int ret;
2702
2703 ee_len = ext4_ext_get_actual_len(ex);
2704 ee_pblock = ext4_ext_pblock(ex);
2705
2706 ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
2707 if (ret > 0)
2708 ret = 0;
2709
2710 return ret;
2711}
2712
2713/*
2714 * used by extent splitting.
2715 */
2716#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
2717 due to ENOSPC */
2718#define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */
2719#define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */
2720
2721/*
2722 * ext4_split_extent_at() splits an extent at given block.
2723 *
2724 * @handle: the journal handle
2725 * @inode: the file inode
2726 * @path: the path to the extent
2727 * @split: the logical block where the extent is splitted.
2728 * @split_flags: indicates if the extent could be zeroout if split fails, and
2729 * the states(init or uninit) of new extents.
2730 * @flags: flags used to insert new extent to extent tree.
2731 *
2732 *
2733 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
2734 * of which are deterimined by split_flag.
2735 *
2736 * There are two cases:
2737 * a> the extent are splitted into two extent.
2738 * b> split is not needed, and just mark the extent.
2739 *
2740 * return 0 on success.
2741 */
2742static int ext4_split_extent_at(handle_t *handle,
2743 struct inode *inode,
2744 struct ext4_ext_path *path,
2745 ext4_lblk_t split,
2746 int split_flag,
2747 int flags)
2748{
2749 ext4_fsblk_t newblock;
2750 ext4_lblk_t ee_block;
2751 struct ext4_extent *ex, newex, orig_ex;
2752 struct ext4_extent *ex2 = NULL;
2753 unsigned int ee_len, depth;
2754 int err = 0;
2755
2756 ext_debug("ext4_split_extents_at: inode %lu, logical"
2757 "block %llu\n", inode->i_ino, (unsigned long long)split);
2758
2759 ext4_ext_show_leaf(inode, path);
2760
2761 depth = ext_depth(inode);
2762 ex = path[depth].p_ext;
2763 ee_block = le32_to_cpu(ex->ee_block);
2764 ee_len = ext4_ext_get_actual_len(ex);
2765 newblock = split - ee_block + ext4_ext_pblock(ex);
2766
2767 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
2768
2769 err = ext4_ext_get_access(handle, inode, path + depth);
2770 if (err)
2771 goto out;
2772
2773 if (split == ee_block) {
2774 /*
2775 * case b: block @split is the block that the extent begins with
2776 * then we just change the state of the extent, and splitting
2777 * is not needed.
2778 */
2779 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2780 ext4_ext_mark_uninitialized(ex);
2781 else
2782 ext4_ext_mark_initialized(ex);
2783
2784 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
2785 ext4_ext_try_to_merge(inode, path, ex);
2786
2787 err = ext4_ext_dirty(handle, inode, path + depth);
2788 goto out;
2789 }
2790
2791 /* case a */
2792 memcpy(&orig_ex, ex, sizeof(orig_ex));
2793 ex->ee_len = cpu_to_le16(split - ee_block);
2794 if (split_flag & EXT4_EXT_MARK_UNINIT1)
2795 ext4_ext_mark_uninitialized(ex);
2796
2797 /*
2798 * path may lead to new leaf, not to original leaf any more
2799 * after ext4_ext_insert_extent() returns,
2800 */
2801 err = ext4_ext_dirty(handle, inode, path + depth);
2802 if (err)
2803 goto fix_extent_len;
2804
2805 ex2 = &newex;
2806 ex2->ee_block = cpu_to_le32(split);
2807 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
2808 ext4_ext_store_pblock(ex2, newblock);
2809 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2810 ext4_ext_mark_uninitialized(ex2);
2811
2812 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2813 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2814 err = ext4_ext_zeroout(inode, &orig_ex);
2815 if (err)
2816 goto fix_extent_len;
2817 /* update the extent length and mark as initialized */
2818 ex->ee_len = cpu_to_le32(ee_len);
2819 ext4_ext_try_to_merge(inode, path, ex);
2820 err = ext4_ext_dirty(handle, inode, path + depth);
2821 goto out;
2822 } else if (err)
2823 goto fix_extent_len;
2824
2825out:
2826 ext4_ext_show_leaf(inode, path);
2827 return err;
2828
2829fix_extent_len:
2830 ex->ee_len = orig_ex.ee_len;
2831 ext4_ext_dirty(handle, inode, path + depth);
2832 return err;
2833}
2834
2835/*
2836 * ext4_split_extents() splits an extent and mark extent which is covered
2837 * by @map as split_flags indicates
2838 *
2839 * It may result in splitting the extent into multiple extents (upto three)
2840 * There are three possibilities:
2841 * a> There is no split required
2842 * b> Splits in two extents: Split is happening at either end of the extent
2843 * c> Splits in three extents: Somone is splitting in middle of the extent
2844 *
2845 */
2846static int ext4_split_extent(handle_t *handle,
2847 struct inode *inode,
2848 struct ext4_ext_path *path,
2849 struct ext4_map_blocks *map,
2850 int split_flag,
2851 int flags)
2852{
2853 ext4_lblk_t ee_block;
2854 struct ext4_extent *ex;
2855 unsigned int ee_len, depth;
2856 int err = 0;
2857 int uninitialized;
2858 int split_flag1, flags1;
2859
2860 depth = ext_depth(inode);
2861 ex = path[depth].p_ext;
2862 ee_block = le32_to_cpu(ex->ee_block);
2863 ee_len = ext4_ext_get_actual_len(ex);
2864 uninitialized = ext4_ext_is_uninitialized(ex);
2865
2866 if (map->m_lblk + map->m_len < ee_block + ee_len) {
2867 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2868 EXT4_EXT_MAY_ZEROOUT : 0;
2869 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
2870 if (uninitialized)
2871 split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
2872 EXT4_EXT_MARK_UNINIT2;
2873 err = ext4_split_extent_at(handle, inode, path,
2874 map->m_lblk + map->m_len, split_flag1, flags1);
2875 if (err)
2876 goto out;
2877 }
2878
2879 ext4_ext_drop_refs(path);
2880 path = ext4_ext_find_extent(inode, map->m_lblk, path);
2881 if (IS_ERR(path))
2882 return PTR_ERR(path);
2883
2884 if (map->m_lblk >= ee_block) {
2885 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2886 EXT4_EXT_MAY_ZEROOUT : 0;
2887 if (uninitialized)
2888 split_flag1 |= EXT4_EXT_MARK_UNINIT1;
2889 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2890 split_flag1 |= EXT4_EXT_MARK_UNINIT2;
2891 err = ext4_split_extent_at(handle, inode, path,
2892 map->m_lblk, split_flag1, flags);
2893 if (err)
2894 goto out;
2895 }
2896
2897 ext4_ext_show_leaf(inode, path);
2898out:
2899 return err ? err : map->m_len;
2900}
2901
2902#define EXT4_EXT_ZERO_LEN 7
2903/*
2904 * This function is called by ext4_ext_map_blocks() if someone tries to write
2905 * to an uninitialized extent. It may result in splitting the uninitialized
2906 * extent into multiple extents (up to three - one initialized and two
2907 * uninitialized).
2908 * There are three possibilities:
2909 * a> There is no split required: Entire extent should be initialized
2910 * b> Splits in two extents: Write is happening at either end of the extent
2911 * c> Splits in three extents: Somone is writing in middle of the extent
2912 */
2913static int ext4_ext_convert_to_initialized(handle_t *handle,
2914 struct inode *inode,
2915 struct ext4_map_blocks *map,
2916 struct ext4_ext_path *path)
2917{
2918 struct ext4_map_blocks split_map;
2919 struct ext4_extent zero_ex;
2920 struct ext4_extent *ex;
2921 ext4_lblk_t ee_block, eof_block;
2922 unsigned int allocated, ee_len, depth;
2923 int err = 0;
2924 int split_flag = 0;
2925
2926 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
2927 "block %llu, max_blocks %u\n", inode->i_ino,
2928 (unsigned long long)map->m_lblk, map->m_len);
2929
2930 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
2931 inode->i_sb->s_blocksize_bits;
2932 if (eof_block < map->m_lblk + map->m_len)
2933 eof_block = map->m_lblk + map->m_len;
2934
2935 depth = ext_depth(inode);
2936 ex = path[depth].p_ext;
2937 ee_block = le32_to_cpu(ex->ee_block);
2938 ee_len = ext4_ext_get_actual_len(ex);
2939 allocated = ee_len - (map->m_lblk - ee_block);
2940
2941 WARN_ON(map->m_lblk < ee_block);
2942 /*
2943 * It is safe to convert extent to initialized via explicit
2944 * zeroout only if extent is fully insde i_size or new_size.
2945 */
2946 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
2947
2948 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
2949 if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
2950 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2951 err = ext4_ext_zeroout(inode, ex);
2952 if (err)
2953 goto out;
2954
2955 err = ext4_ext_get_access(handle, inode, path + depth);
2956 if (err)
2957 goto out;
2958 ext4_ext_mark_initialized(ex);
2959 ext4_ext_try_to_merge(inode, path, ex);
2960 err = ext4_ext_dirty(handle, inode, path + depth);
2961 goto out;
2962 }
2963
2964 /*
2965 * four cases:
2966 * 1. split the extent into three extents.
2967 * 2. split the extent into two extents, zeroout the first half.
2968 * 3. split the extent into two extents, zeroout the second half.
2969 * 4. split the extent into two extents with out zeroout.
2970 */
2971 split_map.m_lblk = map->m_lblk;
2972 split_map.m_len = map->m_len;
2973
2974 if (allocated > map->m_len) {
2975 if (allocated <= EXT4_EXT_ZERO_LEN &&
2976 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2977 /* case 3 */
2978 zero_ex.ee_block =
2979 cpu_to_le32(map->m_lblk);
2980 zero_ex.ee_len = cpu_to_le16(allocated);
2981 ext4_ext_store_pblock(&zero_ex,
2982 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
2983 err = ext4_ext_zeroout(inode, &zero_ex);
2984 if (err)
2985 goto out;
2986 split_map.m_lblk = map->m_lblk;
2987 split_map.m_len = allocated;
2988 } else if ((map->m_lblk - ee_block + map->m_len <
2989 EXT4_EXT_ZERO_LEN) &&
2990 (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2991 /* case 2 */
2992 if (map->m_lblk != ee_block) {
2993 zero_ex.ee_block = ex->ee_block;
2994 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
2995 ee_block);
2996 ext4_ext_store_pblock(&zero_ex,
2997 ext4_ext_pblock(ex));
2998 err = ext4_ext_zeroout(inode, &zero_ex);
2999 if (err)
3000 goto out;
3001 }
3002
3003 split_map.m_lblk = ee_block;
3004 split_map.m_len = map->m_lblk - ee_block + map->m_len;
3005 allocated = map->m_len;
3006 }
3007 }
3008
3009 allocated = ext4_split_extent(handle, inode, path,
3010 &split_map, split_flag, 0);
3011 if (allocated < 0)
3012 err = allocated;
3013
3014out:
3015 return err ? err : allocated;
3016}
3017
3018/*
3019 * This function is called by ext4_ext_map_blocks() from
3020 * ext4_get_blocks_dio_write() when DIO to write
3021 * to an uninitialized extent.
3022 *
3023 * Writing to an uninitialized extent may result in splitting the uninitialized
3024 * extent into multiple /initialized uninitialized extents (up to three)
3025 * There are three possibilities:
3026 * a> There is no split required: Entire extent should be uninitialized
3027 * b> Splits in two extents: Write is happening at either end of the extent
3028 * c> Splits in three extents: Somone is writing in middle of the extent
3029 *
3030 * One of more index blocks maybe needed if the extent tree grow after
3031 * the uninitialized extent split. To prevent ENOSPC occur at the IO
3032 * complete, we need to split the uninitialized extent before DIO submit
3033 * the IO. The uninitialized extent called at this time will be split
3034 * into three uninitialized extent(at most). After IO complete, the part
3035 * being filled will be convert to initialized by the end_io callback function
3036 * via ext4_convert_unwritten_extents().
3037 *
3038 * Returns the size of uninitialized extent to be written on success.
3039 */
3040static int ext4_split_unwritten_extents(handle_t *handle,
3041 struct inode *inode,
3042 struct ext4_map_blocks *map,
3043 struct ext4_ext_path *path,
3044 int flags)
3045{
3046 ext4_lblk_t eof_block;
3047 ext4_lblk_t ee_block;
3048 struct ext4_extent *ex;
3049 unsigned int ee_len;
3050 int split_flag = 0, depth;
3051
3052 ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3053 "block %llu, max_blocks %u\n", inode->i_ino,
3054 (unsigned long long)map->m_lblk, map->m_len);
3055
3056 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3057 inode->i_sb->s_blocksize_bits;
3058 if (eof_block < map->m_lblk + map->m_len)
3059 eof_block = map->m_lblk + map->m_len;
3060 /*
3061 * It is safe to convert extent to initialized via explicit
3062 * zeroout only if extent is fully insde i_size or new_size.
3063 */
3064 depth = ext_depth(inode);
3065 ex = path[depth].p_ext;
3066 ee_block = le32_to_cpu(ex->ee_block);
3067 ee_len = ext4_ext_get_actual_len(ex);
3068
3069 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3070 split_flag |= EXT4_EXT_MARK_UNINIT2;
3071
3072 flags |= EXT4_GET_BLOCKS_PRE_IO;
3073 return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3074}
3075
3076static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3077 struct inode *inode,
3078 struct ext4_ext_path *path)
3079{
3080 struct ext4_extent *ex;
3081 int depth;
3082 int err = 0;
3083
3084 depth = ext_depth(inode);
3085 ex = path[depth].p_ext;
3086
3087 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3088 "block %llu, max_blocks %u\n", inode->i_ino,
3089 (unsigned long long)le32_to_cpu(ex->ee_block),
3090 ext4_ext_get_actual_len(ex));
3091
3092 err = ext4_ext_get_access(handle, inode, path + depth);
3093 if (err)
3094 goto out;
3095 /* first mark the extent as initialized */
3096 ext4_ext_mark_initialized(ex);
3097
3098 /* note: ext4_ext_correct_indexes() isn't needed here because
3099 * borders are not changed
3100 */
3101 ext4_ext_try_to_merge(inode, path, ex);
3102
3103 /* Mark modified extent as dirty */
3104 err = ext4_ext_dirty(handle, inode, path + depth);
3105out:
3106 ext4_ext_show_leaf(inode, path);
3107 return err;
3108}
3109
3110static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3111 sector_t block, int count)
3112{
3113 int i;
3114 for (i = 0; i < count; i++)
3115 unmap_underlying_metadata(bdev, block + i);
3116}
3117
3118/*
3119 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3120 */
3121static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3122 ext4_lblk_t lblk,
3123 struct ext4_ext_path *path,
3124 unsigned int len)
3125{
3126 int i, depth;
3127 struct ext4_extent_header *eh;
3128 struct ext4_extent *last_ex;
3129
3130 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3131 return 0;
3132
3133 depth = ext_depth(inode);
3134 eh = path[depth].p_hdr;
3135
3136 if (unlikely(!eh->eh_entries)) {
3137 EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
3138 "EOFBLOCKS_FL set");
3139 return -EIO;
3140 }
3141 last_ex = EXT_LAST_EXTENT(eh);
3142 /*
3143 * We should clear the EOFBLOCKS_FL flag if we are writing the
3144 * last block in the last extent in the file. We test this by
3145 * first checking to see if the caller to
3146 * ext4_ext_get_blocks() was interested in the last block (or
3147 * a block beyond the last block) in the current extent. If
3148 * this turns out to be false, we can bail out from this
3149 * function immediately.
3150 */
3151 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3152 ext4_ext_get_actual_len(last_ex))
3153 return 0;
3154 /*
3155 * If the caller does appear to be planning to write at or
3156 * beyond the end of the current extent, we then test to see
3157 * if the current extent is the last extent in the file, by
3158 * checking to make sure it was reached via the rightmost node
3159 * at each level of the tree.
3160 */
3161 for (i = depth-1; i >= 0; i--)
3162 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3163 return 0;
3164 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3165 return ext4_mark_inode_dirty(handle, inode);
3166}
3167
3168static int
3169ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3170 struct ext4_map_blocks *map,
3171 struct ext4_ext_path *path, int flags,
3172 unsigned int allocated, ext4_fsblk_t newblock)
3173{
3174 int ret = 0;
3175 int err = 0;
3176 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3177
3178 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
3179 "block %llu, max_blocks %u, flags %d, allocated %u",
3180 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3181 flags, allocated);
3182 ext4_ext_show_leaf(inode, path);
3183
3184 /* get_block() before submit the IO, split the extent */
3185 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3186 ret = ext4_split_unwritten_extents(handle, inode, map,
3187 path, flags);
3188 /*
3189 * Flag the inode(non aio case) or end_io struct (aio case)
3190 * that this IO needs to conversion to written when IO is
3191 * completed
3192 */
3193 if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3194 io->flag = EXT4_IO_END_UNWRITTEN;
3195 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3196 } else
3197 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3198 if (ext4_should_dioread_nolock(inode))
3199 map->m_flags |= EXT4_MAP_UNINIT;
3200 goto out;
3201 }
3202 /* IO end_io complete, convert the filled extent to written */
3203 if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3204 ret = ext4_convert_unwritten_extents_endio(handle, inode,
3205 path);
3206 if (ret >= 0) {
3207 ext4_update_inode_fsync_trans(handle, inode, 1);
3208 err = check_eofblocks_fl(handle, inode, map->m_lblk,
3209 path, map->m_len);
3210 } else
3211 err = ret;
3212 goto out2;
3213 }
3214 /* buffered IO case */
3215 /*
3216 * repeat fallocate creation request
3217 * we already have an unwritten extent
3218 */
3219 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
3220 goto map_out;
3221
3222 /* buffered READ or buffered write_begin() lookup */
3223 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3224 /*
3225 * We have blocks reserved already. We
3226 * return allocated blocks so that delalloc
3227 * won't do block reservation for us. But
3228 * the buffer head will be unmapped so that
3229 * a read from the block returns 0s.
3230 */
3231 map->m_flags |= EXT4_MAP_UNWRITTEN;
3232 goto out1;
3233 }
3234
3235 /* buffered write, writepage time, convert*/
3236 ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
3237 if (ret >= 0) {
3238 ext4_update_inode_fsync_trans(handle, inode, 1);
3239 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3240 map->m_len);
3241 if (err < 0)
3242 goto out2;
3243 }
3244
3245out:
3246 if (ret <= 0) {
3247 err = ret;
3248 goto out2;
3249 } else
3250 allocated = ret;
3251 map->m_flags |= EXT4_MAP_NEW;
3252 /*
3253 * if we allocated more blocks than requested
3254 * we need to make sure we unmap the extra block
3255 * allocated. The actual needed block will get
3256 * unmapped later when we find the buffer_head marked
3257 * new.
3258 */
3259 if (allocated > map->m_len) {
3260 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3261 newblock + map->m_len,
3262 allocated - map->m_len);
3263 allocated = map->m_len;
3264 }
3265
3266 /*
3267 * If we have done fallocate with the offset that is already
3268 * delayed allocated, we would have block reservation
3269 * and quota reservation done in the delayed write path.
3270 * But fallocate would have already updated quota and block
3271 * count for this offset. So cancel these reservation
3272 */
3273 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3274 ext4_da_update_reserve_space(inode, allocated, 0);
3275
3276map_out:
3277 map->m_flags |= EXT4_MAP_MAPPED;
3278out1:
3279 if (allocated > map->m_len)
3280 allocated = map->m_len;
3281 ext4_ext_show_leaf(inode, path);
3282 map->m_pblk = newblock;
3283 map->m_len = allocated;
3284out2:
3285 if (path) {
3286 ext4_ext_drop_refs(path);
3287 kfree(path);
3288 }
3289 return err ? err : allocated;
3290}
3291
3292/*
3293 * Block allocation/map/preallocation routine for extents based files
3294 *
3295 *
3296 * Need to be called with
3297 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3298 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3299 *
3300 * return > 0, number of of blocks already mapped/allocated
3301 * if create == 0 and these are pre-allocated blocks
3302 * buffer head is unmapped
3303 * otherwise blocks are mapped
3304 *
3305 * return = 0, if plain look up failed (blocks have not been allocated)
3306 * buffer head is unmapped
3307 *
3308 * return < 0, error case.
3309 */
3310int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
3311 struct ext4_map_blocks *map, int flags)
3312{
3313 struct ext4_ext_path *path = NULL;
3314 struct ext4_extent newex, *ex;
3315 ext4_fsblk_t newblock = 0;
3316 int err = 0, depth, ret;
3317 unsigned int allocated = 0;
3318 unsigned int punched_out = 0;
3319 unsigned int result = 0;
3320 struct ext4_allocation_request ar;
3321 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3322 struct ext4_map_blocks punch_map;
3323
3324 ext_debug("blocks %u/%u requested for inode %lu\n",
3325 map->m_lblk, map->m_len, inode->i_ino);
3326 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
3327
3328 /* check in cache */
3329 if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) &&
3330 ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
3331 if (!newex.ee_start_lo && !newex.ee_start_hi) {
3332 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3333 /*
3334 * block isn't allocated yet and
3335 * user doesn't want to allocate it
3336 */
3337 goto out2;
3338 }
3339 /* we should allocate requested block */
3340 } else {
3341 /* block is already allocated */
3342 newblock = map->m_lblk
3343 - le32_to_cpu(newex.ee_block)
3344 + ext4_ext_pblock(&newex);
3345 /* number of remaining blocks in the extent */
3346 allocated = ext4_ext_get_actual_len(&newex) -
3347 (map->m_lblk - le32_to_cpu(newex.ee_block));
3348 goto out;
3349 }
3350 }
3351
3352 /* find extent for this block */
3353 path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
3354 if (IS_ERR(path)) {
3355 err = PTR_ERR(path);
3356 path = NULL;
3357 goto out2;
3358 }
3359
3360 depth = ext_depth(inode);
3361
3362 /*
3363 * consistent leaf must not be empty;
3364 * this situation is possible, though, _during_ tree modification;
3365 * this is why assert can't be put in ext4_ext_find_extent()
3366 */
3367 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
3368 EXT4_ERROR_INODE(inode, "bad extent address "
3369 "lblock: %lu, depth: %d pblock %lld",
3370 (unsigned long) map->m_lblk, depth,
3371 path[depth].p_block);
3372 err = -EIO;
3373 goto out2;
3374 }
3375
3376 ex = path[depth].p_ext;
3377 if (ex) {
3378 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3379 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3380 unsigned short ee_len;
3381
3382 /*
3383 * Uninitialized extents are treated as holes, except that
3384 * we split out initialized portions during a write.
3385 */
3386 ee_len = ext4_ext_get_actual_len(ex);
3387 /* if found extent covers block, simply return it */
3388 if (in_range(map->m_lblk, ee_block, ee_len)) {
3389 newblock = map->m_lblk - ee_block + ee_start;
3390 /* number of remaining blocks in the extent */
3391 allocated = ee_len - (map->m_lblk - ee_block);
3392 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
3393 ee_block, ee_len, newblock);
3394
3395 if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
3396 /*
3397 * Do not put uninitialized extent
3398 * in the cache
3399 */
3400 if (!ext4_ext_is_uninitialized(ex)) {
3401 ext4_ext_put_in_cache(inode, ee_block,
3402 ee_len, ee_start);
3403 goto out;
3404 }
3405 ret = ext4_ext_handle_uninitialized_extents(
3406 handle, inode, map, path, flags,
3407 allocated, newblock);
3408 return ret;
3409 }
3410
3411 /*
3412 * Punch out the map length, but only to the
3413 * end of the extent
3414 */
3415 punched_out = allocated < map->m_len ?
3416 allocated : map->m_len;
3417
3418 /*
3419 * Sense extents need to be converted to
3420 * uninitialized, they must fit in an
3421 * uninitialized extent
3422 */
3423 if (punched_out > EXT_UNINIT_MAX_LEN)
3424 punched_out = EXT_UNINIT_MAX_LEN;
3425
3426 punch_map.m_lblk = map->m_lblk;
3427 punch_map.m_pblk = newblock;
3428 punch_map.m_len = punched_out;
3429 punch_map.m_flags = 0;
3430
3431 /* Check to see if the extent needs to be split */
3432 if (punch_map.m_len != ee_len ||
3433 punch_map.m_lblk != ee_block) {
3434
3435 ret = ext4_split_extent(handle, inode,
3436 path, &punch_map, 0,
3437 EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
3438 EXT4_GET_BLOCKS_PRE_IO);
3439
3440 if (ret < 0) {
3441 err = ret;
3442 goto out2;
3443 }
3444 /*
3445 * find extent for the block at
3446 * the start of the hole
3447 */
3448 ext4_ext_drop_refs(path);
3449 kfree(path);
3450
3451 path = ext4_ext_find_extent(inode,
3452 map->m_lblk, NULL);
3453 if (IS_ERR(path)) {
3454 err = PTR_ERR(path);
3455 path = NULL;
3456 goto out2;
3457 }
3458
3459 depth = ext_depth(inode);
3460 ex = path[depth].p_ext;
3461 ee_len = ext4_ext_get_actual_len(ex);
3462 ee_block = le32_to_cpu(ex->ee_block);
3463 ee_start = ext4_ext_pblock(ex);
3464
3465 }
3466
3467 ext4_ext_mark_uninitialized(ex);
3468
3469 ext4_ext_invalidate_cache(inode);
3470
3471 err = ext4_ext_rm_leaf(handle, inode, path,
3472 map->m_lblk, map->m_lblk + punched_out);
3473
3474 if (!err && path->p_hdr->eh_entries == 0) {
3475 /*
3476 * Punch hole freed all of this sub tree,
3477 * so we need to correct eh_depth
3478 */
3479 err = ext4_ext_get_access(handle, inode, path);
3480 if (err == 0) {
3481 ext_inode_hdr(inode)->eh_depth = 0;
3482 ext_inode_hdr(inode)->eh_max =
3483 cpu_to_le16(ext4_ext_space_root(
3484 inode, 0));
3485
3486 err = ext4_ext_dirty(
3487 handle, inode, path);
3488 }
3489 }
3490
3491 goto out2;
3492 }
3493 }
3494
3495 /*
3496 * requested block isn't allocated yet;
3497 * we couldn't try to create block if create flag is zero
3498 */
3499 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3500 /*
3501 * put just found gap into cache to speed up
3502 * subsequent requests
3503 */
3504 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
3505 goto out2;
3506 }
3507 /*
3508 * Okay, we need to do block allocation.
3509 */
3510
3511 /* find neighbour allocated blocks */
3512 ar.lleft = map->m_lblk;
3513 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3514 if (err)
3515 goto out2;
3516 ar.lright = map->m_lblk;
3517 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
3518 if (err)
3519 goto out2;
3520
3521 /*
3522 * See if request is beyond maximum number of blocks we can have in
3523 * a single extent. For an initialized extent this limit is
3524 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
3525 * EXT_UNINIT_MAX_LEN.
3526 */
3527 if (map->m_len > EXT_INIT_MAX_LEN &&
3528 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3529 map->m_len = EXT_INIT_MAX_LEN;
3530 else if (map->m_len > EXT_UNINIT_MAX_LEN &&
3531 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3532 map->m_len = EXT_UNINIT_MAX_LEN;
3533
3534 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
3535 newex.ee_block = cpu_to_le32(map->m_lblk);
3536 newex.ee_len = cpu_to_le16(map->m_len);
3537 err = ext4_ext_check_overlap(inode, &newex, path);
3538 if (err)
3539 allocated = ext4_ext_get_actual_len(&newex);
3540 else
3541 allocated = map->m_len;
3542
3543 /* allocate new block */
3544 ar.inode = inode;
3545 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
3546 ar.logical = map->m_lblk;
3547 ar.len = allocated;
3548 if (S_ISREG(inode->i_mode))
3549 ar.flags = EXT4_MB_HINT_DATA;
3550 else
3551 /* disable in-core preallocation for non-regular files */
3552 ar.flags = 0;
3553 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
3554 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
3555 newblock = ext4_mb_new_blocks(handle, &ar, &err);
3556 if (!newblock)
3557 goto out2;
3558 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
3559 ar.goal, newblock, allocated);
3560
3561 /* try to insert new extent into found leaf and return */
3562 ext4_ext_store_pblock(&newex, newblock);
3563 newex.ee_len = cpu_to_le16(ar.len);
3564 /* Mark uninitialized */
3565 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
3566 ext4_ext_mark_uninitialized(&newex);
3567 /*
3568 * io_end structure was created for every IO write to an
3569 * uninitialized extent. To avoid unnecessary conversion,
3570 * here we flag the IO that really needs the conversion.
3571 * For non asycn direct IO case, flag the inode state
3572 * that we need to perform conversion when IO is done.
3573 */
3574 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3575 if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3576 io->flag = EXT4_IO_END_UNWRITTEN;
3577 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3578 } else
3579 ext4_set_inode_state(inode,
3580 EXT4_STATE_DIO_UNWRITTEN);
3581 }
3582 if (ext4_should_dioread_nolock(inode))
3583 map->m_flags |= EXT4_MAP_UNINIT;
3584 }
3585
3586 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
3587 if (!err)
3588 err = ext4_ext_insert_extent(handle, inode, path,
3589 &newex, flags);
3590 if (err) {
3591 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
3592 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
3593 /* free data blocks we just allocated */
3594 /* not a good idea to call discard here directly,
3595 * but otherwise we'd need to call it every free() */
3596 ext4_discard_preallocations(inode);
3597 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
3598 ext4_ext_get_actual_len(&newex), fb_flags);
3599 goto out2;
3600 }
3601
3602 /* previous routine could use block we allocated */
3603 newblock = ext4_ext_pblock(&newex);
3604 allocated = ext4_ext_get_actual_len(&newex);
3605 if (allocated > map->m_len)
3606 allocated = map->m_len;
3607 map->m_flags |= EXT4_MAP_NEW;
3608
3609 /*
3610 * Update reserved blocks/metadata blocks after successful
3611 * block allocation which had been deferred till now.
3612 */
3613 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3614 ext4_da_update_reserve_space(inode, allocated, 1);
3615
3616 /*
3617 * Cache the extent and update transaction to commit on fdatasync only
3618 * when it is _not_ an uninitialized extent.
3619 */
3620 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
3621 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
3622 ext4_update_inode_fsync_trans(handle, inode, 1);
3623 } else
3624 ext4_update_inode_fsync_trans(handle, inode, 0);
3625out:
3626 if (allocated > map->m_len)
3627 allocated = map->m_len;
3628 ext4_ext_show_leaf(inode, path);
3629 map->m_flags |= EXT4_MAP_MAPPED;
3630 map->m_pblk = newblock;
3631 map->m_len = allocated;
3632out2:
3633 if (path) {
3634 ext4_ext_drop_refs(path);
3635 kfree(path);
3636 }
3637 trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
3638 newblock, map->m_len, err ? err : allocated);
3639
3640 result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
3641 punched_out : allocated;
3642
3643 return err ? err : result;
3644}
3645
3646void ext4_ext_truncate(struct inode *inode)
3647{
3648 struct address_space *mapping = inode->i_mapping;
3649 struct super_block *sb = inode->i_sb;
3650 ext4_lblk_t last_block;
3651 handle_t *handle;
3652 int err = 0;
3653
3654 /*
3655 * finish any pending end_io work so we won't run the risk of
3656 * converting any truncated blocks to initialized later
3657 */
3658 ext4_flush_completed_IO(inode);
3659
3660 /*
3661 * probably first extent we're gonna free will be last in block
3662 */
3663 err = ext4_writepage_trans_blocks(inode);
3664 handle = ext4_journal_start(inode, err);
3665 if (IS_ERR(handle))
3666 return;
3667
3668 if (inode->i_size & (sb->s_blocksize - 1))
3669 ext4_block_truncate_page(handle, mapping, inode->i_size);
3670
3671 if (ext4_orphan_add(handle, inode))
3672 goto out_stop;
3673
3674 down_write(&EXT4_I(inode)->i_data_sem);
3675 ext4_ext_invalidate_cache(inode);
3676
3677 ext4_discard_preallocations(inode);
3678
3679 /*
3680 * TODO: optimization is possible here.
3681 * Probably we need not scan at all,
3682 * because page truncation is enough.
3683 */
3684
3685 /* we have to know where to truncate from in crash case */
3686 EXT4_I(inode)->i_disksize = inode->i_size;
3687 ext4_mark_inode_dirty(handle, inode);
3688
3689 last_block = (inode->i_size + sb->s_blocksize - 1)
3690 >> EXT4_BLOCK_SIZE_BITS(sb);
3691 err = ext4_ext_remove_space(inode, last_block);
3692
3693 /* In a multi-transaction truncate, we only make the final
3694 * transaction synchronous.
3695 */
3696 if (IS_SYNC(inode))
3697 ext4_handle_sync(handle);
3698
3699 up_write(&EXT4_I(inode)->i_data_sem);
3700
3701out_stop:
3702 /*
3703 * If this was a simple ftruncate() and the file will remain alive,
3704 * then we need to clear up the orphan record which we created above.
3705 * However, if this was a real unlink then we were called by
3706 * ext4_delete_inode(), and we allow that function to clean up the
3707 * orphan info for us.
3708 */
3709 if (inode->i_nlink)
3710 ext4_orphan_del(handle, inode);
3711
3712 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3713 ext4_mark_inode_dirty(handle, inode);
3714 ext4_journal_stop(handle);
3715}
3716
3717static void ext4_falloc_update_inode(struct inode *inode,
3718 int mode, loff_t new_size, int update_ctime)
3719{
3720 struct timespec now;
3721
3722 if (update_ctime) {
3723 now = current_fs_time(inode->i_sb);
3724 if (!timespec_equal(&inode->i_ctime, &now))
3725 inode->i_ctime = now;
3726 }
3727 /*
3728 * Update only when preallocation was requested beyond
3729 * the file size.
3730 */
3731 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3732 if (new_size > i_size_read(inode))
3733 i_size_write(inode, new_size);
3734 if (new_size > EXT4_I(inode)->i_disksize)
3735 ext4_update_i_disksize(inode, new_size);
3736 } else {
3737 /*
3738 * Mark that we allocate beyond EOF so the subsequent truncate
3739 * can proceed even if the new size is the same as i_size.
3740 */
3741 if (new_size > i_size_read(inode))
3742 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3743 }
3744
3745}
3746
3747/*
3748 * preallocate space for a file. This implements ext4's fallocate file
3749 * operation, which gets called from sys_fallocate system call.
3750 * For block-mapped files, posix_fallocate should fall back to the method
3751 * of writing zeroes to the required new blocks (the same behavior which is
3752 * expected for file systems which do not support fallocate() system call).
3753 */
3754long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
3755{
3756 struct inode *inode = file->f_path.dentry->d_inode;
3757 handle_t *handle;
3758 loff_t new_size;
3759 unsigned int max_blocks;
3760 int ret = 0;
3761 int ret2 = 0;
3762 int retries = 0;
3763 struct ext4_map_blocks map;
3764 unsigned int credits, blkbits = inode->i_blkbits;
3765
3766 /*
3767 * currently supporting (pre)allocate mode for extent-based
3768 * files _only_
3769 */
3770 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
3771 return -EOPNOTSUPP;
3772
3773 /* Return error if mode is not supported */
3774 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
3775 return -EOPNOTSUPP;
3776
3777 if (mode & FALLOC_FL_PUNCH_HOLE)
3778 return ext4_punch_hole(file, offset, len);
3779
3780 trace_ext4_fallocate_enter(inode, offset, len, mode);
3781 map.m_lblk = offset >> blkbits;
3782 /*
3783 * We can't just convert len to max_blocks because
3784 * If blocksize = 4096 offset = 3072 and len = 2048
3785 */
3786 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3787 - map.m_lblk;
3788 /*
3789 * credits to insert 1 extent into extent tree
3790 */
3791 credits = ext4_chunk_trans_blocks(inode, max_blocks);
3792 mutex_lock(&inode->i_mutex);
3793 ret = inode_newsize_ok(inode, (len + offset));
3794 if (ret) {
3795 mutex_unlock(&inode->i_mutex);
3796 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
3797 return ret;
3798 }
3799retry:
3800 while (ret >= 0 && ret < max_blocks) {
3801 map.m_lblk = map.m_lblk + ret;
3802 map.m_len = max_blocks = max_blocks - ret;
3803 handle = ext4_journal_start(inode, credits);
3804 if (IS_ERR(handle)) {
3805 ret = PTR_ERR(handle);
3806 break;
3807 }
3808 ret = ext4_map_blocks(handle, inode, &map,
3809 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
3810 EXT4_GET_BLOCKS_NO_NORMALIZE);
3811 if (ret <= 0) {
3812#ifdef EXT4FS_DEBUG
3813 WARN_ON(ret <= 0);
3814 printk(KERN_ERR "%s: ext4_ext_map_blocks "
3815 "returned error inode#%lu, block=%u, "
3816 "max_blocks=%u", __func__,
3817 inode->i_ino, map.m_lblk, max_blocks);
3818#endif
3819 ext4_mark_inode_dirty(handle, inode);
3820 ret2 = ext4_journal_stop(handle);
3821 break;
3822 }
3823 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
3824 blkbits) >> blkbits))
3825 new_size = offset + len;
3826 else
3827 new_size = ((loff_t) map.m_lblk + ret) << blkbits;
3828
3829 ext4_falloc_update_inode(inode, mode, new_size,
3830 (map.m_flags & EXT4_MAP_NEW));
3831 ext4_mark_inode_dirty(handle, inode);
3832 ret2 = ext4_journal_stop(handle);
3833 if (ret2)
3834 break;
3835 }
3836 if (ret == -ENOSPC &&
3837 ext4_should_retry_alloc(inode->i_sb, &retries)) {
3838 ret = 0;
3839 goto retry;
3840 }
3841 mutex_unlock(&inode->i_mutex);
3842 trace_ext4_fallocate_exit(inode, offset, max_blocks,
3843 ret > 0 ? ret2 : ret);
3844 return ret > 0 ? ret2 : ret;
3845}
3846
3847/*
3848 * This function convert a range of blocks to written extents
3849 * The caller of this function will pass the start offset and the size.
3850 * all unwritten extents within this range will be converted to
3851 * written extents.
3852 *
3853 * This function is called from the direct IO end io call back
3854 * function, to convert the fallocated extents after IO is completed.
3855 * Returns 0 on success.
3856 */
3857int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
3858 ssize_t len)
3859{
3860 handle_t *handle;
3861 unsigned int max_blocks;
3862 int ret = 0;
3863 int ret2 = 0;
3864 struct ext4_map_blocks map;
3865 unsigned int credits, blkbits = inode->i_blkbits;
3866
3867 map.m_lblk = offset >> blkbits;
3868 /*
3869 * We can't just convert len to max_blocks because
3870 * If blocksize = 4096 offset = 3072 and len = 2048
3871 */
3872 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
3873 map.m_lblk);
3874 /*
3875 * credits to insert 1 extent into extent tree
3876 */
3877 credits = ext4_chunk_trans_blocks(inode, max_blocks);
3878 while (ret >= 0 && ret < max_blocks) {
3879 map.m_lblk += ret;
3880 map.m_len = (max_blocks -= ret);
3881 handle = ext4_journal_start(inode, credits);
3882 if (IS_ERR(handle)) {
3883 ret = PTR_ERR(handle);
3884 break;
3885 }
3886 ret = ext4_map_blocks(handle, inode, &map,
3887 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
3888 if (ret <= 0) {
3889 WARN_ON(ret <= 0);
3890 printk(KERN_ERR "%s: ext4_ext_map_blocks "
3891 "returned error inode#%lu, block=%u, "
3892 "max_blocks=%u", __func__,
3893 inode->i_ino, map.m_lblk, map.m_len);
3894 }
3895 ext4_mark_inode_dirty(handle, inode);
3896 ret2 = ext4_journal_stop(handle);
3897 if (ret <= 0 || ret2 )
3898 break;
3899 }
3900 return ret > 0 ? ret2 : ret;
3901}
3902
3903/*
3904 * Callback function called for each extent to gather FIEMAP information.
3905 */
3906static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next,
3907 struct ext4_ext_cache *newex, struct ext4_extent *ex,
3908 void *data)
3909{
3910 __u64 logical;
3911 __u64 physical;
3912 __u64 length;
3913 __u32 flags = 0;
3914 int ret = 0;
3915 struct fiemap_extent_info *fieinfo = data;
3916 unsigned char blksize_bits;
3917
3918 blksize_bits = inode->i_sb->s_blocksize_bits;
3919 logical = (__u64)newex->ec_block << blksize_bits;
3920
3921 if (newex->ec_start == 0) {
3922 /*
3923 * No extent in extent-tree contains block @newex->ec_start,
3924 * then the block may stay in 1)a hole or 2)delayed-extent.
3925 *
3926 * Holes or delayed-extents are processed as follows.
3927 * 1. lookup dirty pages with specified range in pagecache.
3928 * If no page is got, then there is no delayed-extent and
3929 * return with EXT_CONTINUE.
3930 * 2. find the 1st mapped buffer,
3931 * 3. check if the mapped buffer is both in the request range
3932 * and a delayed buffer. If not, there is no delayed-extent,
3933 * then return.
3934 * 4. a delayed-extent is found, the extent will be collected.
3935 */
3936 ext4_lblk_t end = 0;
3937 pgoff_t last_offset;
3938 pgoff_t offset;
3939 pgoff_t index;
3940 pgoff_t start_index = 0;
3941 struct page **pages = NULL;
3942 struct buffer_head *bh = NULL;
3943 struct buffer_head *head = NULL;
3944 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
3945
3946 pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
3947 if (pages == NULL)
3948 return -ENOMEM;
3949
3950 offset = logical >> PAGE_SHIFT;
3951repeat:
3952 last_offset = offset;
3953 head = NULL;
3954 ret = find_get_pages_tag(inode->i_mapping, &offset,
3955 PAGECACHE_TAG_DIRTY, nr_pages, pages);
3956
3957 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
3958 /* First time, try to find a mapped buffer. */
3959 if (ret == 0) {
3960out:
3961 for (index = 0; index < ret; index++)
3962 page_cache_release(pages[index]);
3963 /* just a hole. */
3964 kfree(pages);
3965 return EXT_CONTINUE;
3966 }
3967 index = 0;
3968
3969next_page:
3970 /* Try to find the 1st mapped buffer. */
3971 end = ((__u64)pages[index]->index << PAGE_SHIFT) >>
3972 blksize_bits;
3973 if (!page_has_buffers(pages[index]))
3974 goto out;
3975 head = page_buffers(pages[index]);
3976 if (!head)
3977 goto out;
3978
3979 index++;
3980 bh = head;
3981 do {
3982 if (end >= newex->ec_block +
3983 newex->ec_len)
3984 /* The buffer is out of
3985 * the request range.
3986 */
3987 goto out;
3988
3989 if (buffer_mapped(bh) &&
3990 end >= newex->ec_block) {
3991 start_index = index - 1;
3992 /* get the 1st mapped buffer. */
3993 goto found_mapped_buffer;
3994 }
3995
3996 bh = bh->b_this_page;
3997 end++;
3998 } while (bh != head);
3999
4000 /* No mapped buffer in the range found in this page,
4001 * We need to look up next page.
4002 */
4003 if (index >= ret) {
4004 /* There is no page left, but we need to limit
4005 * newex->ec_len.
4006 */
4007 newex->ec_len = end - newex->ec_block;
4008 goto out;
4009 }
4010 goto next_page;
4011 } else {
4012 /*Find contiguous delayed buffers. */
4013 if (ret > 0 && pages[0]->index == last_offset)
4014 head = page_buffers(pages[0]);
4015 bh = head;
4016 index = 1;
4017 start_index = 0;
4018 }
4019
4020found_mapped_buffer:
4021 if (bh != NULL && buffer_delay(bh)) {
4022 /* 1st or contiguous delayed buffer found. */
4023 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
4024 /*
4025 * 1st delayed buffer found, record
4026 * the start of extent.
4027 */
4028 flags |= FIEMAP_EXTENT_DELALLOC;
4029 newex->ec_block = end;
4030 logical = (__u64)end << blksize_bits;
4031 }
4032 /* Find contiguous delayed buffers. */
4033 do {
4034 if (!buffer_delay(bh))
4035 goto found_delayed_extent;
4036 bh = bh->b_this_page;
4037 end++;
4038 } while (bh != head);
4039
4040 for (; index < ret; index++) {
4041 if (!page_has_buffers(pages[index])) {
4042 bh = NULL;
4043 break;
4044 }
4045 head = page_buffers(pages[index]);
4046 if (!head) {
4047 bh = NULL;
4048 break;
4049 }
4050
4051 if (pages[index]->index !=
4052 pages[start_index]->index + index
4053 - start_index) {
4054 /* Blocks are not contiguous. */
4055 bh = NULL;
4056 break;
4057 }
4058 bh = head;
4059 do {
4060 if (!buffer_delay(bh))
4061 /* Delayed-extent ends. */
4062 goto found_delayed_extent;
4063 bh = bh->b_this_page;
4064 end++;
4065 } while (bh != head);
4066 }
4067 } else if (!(flags & FIEMAP_EXTENT_DELALLOC))
4068 /* a hole found. */
4069 goto out;
4070
4071found_delayed_extent:
4072 newex->ec_len = min(end - newex->ec_block,
4073 (ext4_lblk_t)EXT_INIT_MAX_LEN);
4074 if (ret == nr_pages && bh != NULL &&
4075 newex->ec_len < EXT_INIT_MAX_LEN &&
4076 buffer_delay(bh)) {
4077 /* Have not collected an extent and continue. */
4078 for (index = 0; index < ret; index++)
4079 page_cache_release(pages[index]);
4080 goto repeat;
4081 }
4082
4083 for (index = 0; index < ret; index++)
4084 page_cache_release(pages[index]);
4085 kfree(pages);
4086 }
4087
4088 physical = (__u64)newex->ec_start << blksize_bits;
4089 length = (__u64)newex->ec_len << blksize_bits;
4090
4091 if (ex && ext4_ext_is_uninitialized(ex))
4092 flags |= FIEMAP_EXTENT_UNWRITTEN;
4093
4094 if (next == EXT_MAX_BLOCKS)
4095 flags |= FIEMAP_EXTENT_LAST;
4096
4097 ret = fiemap_fill_next_extent(fieinfo, logical, physical,
4098 length, flags);
4099 if (ret < 0)
4100 return ret;
4101 if (ret == 1)
4102 return EXT_BREAK;
4103 return EXT_CONTINUE;
4104}
4105
4106/* fiemap flags we can handle specified here */
4107#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4108
4109static int ext4_xattr_fiemap(struct inode *inode,
4110 struct fiemap_extent_info *fieinfo)
4111{
4112 __u64 physical = 0;
4113 __u64 length;
4114 __u32 flags = FIEMAP_EXTENT_LAST;
4115 int blockbits = inode->i_sb->s_blocksize_bits;
4116 int error = 0;
4117
4118 /* in-inode? */
4119 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4120 struct ext4_iloc iloc;
4121 int offset; /* offset of xattr in inode */
4122
4123 error = ext4_get_inode_loc(inode, &iloc);
4124 if (error)
4125 return error;
4126 physical = iloc.bh->b_blocknr << blockbits;
4127 offset = EXT4_GOOD_OLD_INODE_SIZE +
4128 EXT4_I(inode)->i_extra_isize;
4129 physical += offset;
4130 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4131 flags |= FIEMAP_EXTENT_DATA_INLINE;
4132 brelse(iloc.bh);
4133 } else { /* external block */
4134 physical = EXT4_I(inode)->i_file_acl << blockbits;
4135 length = inode->i_sb->s_blocksize;
4136 }
4137
4138 if (physical)
4139 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4140 length, flags);
4141 return (error < 0 ? error : 0);
4142}
4143
4144/*
4145 * ext4_ext_punch_hole
4146 *
4147 * Punches a hole of "length" bytes in a file starting
4148 * at byte "offset"
4149 *
4150 * @inode: The inode of the file to punch a hole in
4151 * @offset: The starting byte offset of the hole
4152 * @length: The length of the hole
4153 *
4154 * Returns the number of blocks removed or negative on err
4155 */
4156int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
4157{
4158 struct inode *inode = file->f_path.dentry->d_inode;
4159 struct super_block *sb = inode->i_sb;
4160 struct ext4_ext_cache cache_ex;
4161 ext4_lblk_t first_block, last_block, num_blocks, iblock, max_blocks;
4162 struct address_space *mapping = inode->i_mapping;
4163 struct ext4_map_blocks map;
4164 handle_t *handle;
4165 loff_t first_block_offset, last_block_offset, block_len;
4166 loff_t first_page, last_page, first_page_offset, last_page_offset;
4167 int ret, credits, blocks_released, err = 0;
4168
4169 first_block = (offset + sb->s_blocksize - 1) >>
4170 EXT4_BLOCK_SIZE_BITS(sb);
4171 last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4172
4173 first_block_offset = first_block << EXT4_BLOCK_SIZE_BITS(sb);
4174 last_block_offset = last_block << EXT4_BLOCK_SIZE_BITS(sb);
4175
4176 first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
4177 last_page = (offset + length) >> PAGE_CACHE_SHIFT;
4178
4179 first_page_offset = first_page << PAGE_CACHE_SHIFT;
4180 last_page_offset = last_page << PAGE_CACHE_SHIFT;
4181
4182 /*
4183 * Write out all dirty pages to avoid race conditions
4184 * Then release them.
4185 */
4186 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4187 err = filemap_write_and_wait_range(mapping,
4188 first_page_offset == 0 ? 0 : first_page_offset-1,
4189 last_page_offset);
4190
4191 if (err)
4192 return err;
4193 }
4194
4195 /* Now release the pages */
4196 if (last_page_offset > first_page_offset) {
4197 truncate_inode_pages_range(mapping, first_page_offset,
4198 last_page_offset-1);
4199 }
4200
4201 /* finish any pending end_io work */
4202 ext4_flush_completed_IO(inode);
4203
4204 credits = ext4_writepage_trans_blocks(inode);
4205 handle = ext4_journal_start(inode, credits);
4206 if (IS_ERR(handle))
4207 return PTR_ERR(handle);
4208
4209 err = ext4_orphan_add(handle, inode);
4210 if (err)
4211 goto out;
4212
4213 /*
4214 * Now we need to zero out the un block aligned data.
4215 * If the file is smaller than a block, just
4216 * zero out the middle
4217 */
4218 if (first_block > last_block)
4219 ext4_block_zero_page_range(handle, mapping, offset, length);
4220 else {
4221 /* zero out the head of the hole before the first block */
4222 block_len = first_block_offset - offset;
4223 if (block_len > 0)
4224 ext4_block_zero_page_range(handle, mapping,
4225 offset, block_len);
4226
4227 /* zero out the tail of the hole after the last block */
4228 block_len = offset + length - last_block_offset;
4229 if (block_len > 0) {
4230 ext4_block_zero_page_range(handle, mapping,
4231 last_block_offset, block_len);
4232 }
4233 }
4234
4235 /* If there are no blocks to remove, return now */
4236 if (first_block >= last_block)
4237 goto out;
4238
4239 down_write(&EXT4_I(inode)->i_data_sem);
4240 ext4_ext_invalidate_cache(inode);
4241 ext4_discard_preallocations(inode);
4242
4243 /*
4244 * Loop over all the blocks and identify blocks
4245 * that need to be punched out
4246 */
4247 iblock = first_block;
4248 blocks_released = 0;
4249 while (iblock < last_block) {
4250 max_blocks = last_block - iblock;
4251 num_blocks = 1;
4252 memset(&map, 0, sizeof(map));
4253 map.m_lblk = iblock;
4254 map.m_len = max_blocks;
4255 ret = ext4_ext_map_blocks(handle, inode, &map,
4256 EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
4257
4258 if (ret > 0) {
4259 blocks_released += ret;
4260 num_blocks = ret;
4261 } else if (ret == 0) {
4262 /*
4263 * If map blocks could not find the block,
4264 * then it is in a hole. If the hole was
4265 * not already cached, then map blocks should
4266 * put it in the cache. So we can get the hole
4267 * out of the cache
4268 */
4269 memset(&cache_ex, 0, sizeof(cache_ex));
4270 if ((ext4_ext_check_cache(inode, iblock, &cache_ex)) &&
4271 !cache_ex.ec_start) {
4272
4273 /* The hole is cached */
4274 num_blocks = cache_ex.ec_block +
4275 cache_ex.ec_len - iblock;
4276
4277 } else {
4278 /* The block could not be identified */
4279 err = -EIO;
4280 break;
4281 }
4282 } else {
4283 /* Map blocks error */
4284 err = ret;
4285 break;
4286 }
4287
4288 if (num_blocks == 0) {
4289 /* This condition should never happen */
4290 ext_debug("Block lookup failed");
4291 err = -EIO;
4292 break;
4293 }
4294
4295 iblock += num_blocks;
4296 }
4297
4298 if (blocks_released > 0) {
4299 ext4_ext_invalidate_cache(inode);
4300 ext4_discard_preallocations(inode);
4301 }
4302
4303 if (IS_SYNC(inode))
4304 ext4_handle_sync(handle);
4305
4306 up_write(&EXT4_I(inode)->i_data_sem);
4307
4308out:
4309 ext4_orphan_del(handle, inode);
4310 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4311 ext4_mark_inode_dirty(handle, inode);
4312 ext4_journal_stop(handle);
4313 return err;
4314}
4315int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4316 __u64 start, __u64 len)
4317{
4318 ext4_lblk_t start_blk;
4319 int error = 0;
4320
4321 /* fallback to generic here if not in extents fmt */
4322 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4323 return generic_block_fiemap(inode, fieinfo, start, len,
4324 ext4_get_block);
4325
4326 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4327 return -EBADR;
4328
4329 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4330 error = ext4_xattr_fiemap(inode, fieinfo);
4331 } else {
4332 ext4_lblk_t len_blks;
4333 __u64 last_blk;
4334
4335 start_blk = start >> inode->i_sb->s_blocksize_bits;
4336 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4337 if (last_blk >= EXT_MAX_BLOCKS)
4338 last_blk = EXT_MAX_BLOCKS-1;
4339 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4340
4341 /*
4342 * Walk the extent tree gathering extent information.
4343 * ext4_ext_fiemap_cb will push extents back to user.
4344 */
4345 error = ext4_ext_walk_space(inode, start_blk, len_blks,
4346 ext4_ext_fiemap_cb, fieinfo);
4347 }
4348
4349 return error;
4350}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
4 * Written by Alex Tomas <alex@clusterfs.com>
5 *
6 * Architecture independence:
7 * Copyright (c) 2005, Bull S.A.
8 * Written by Pierre Peiffer <pierre.peiffer@bull.net>
9 */
10
11/*
12 * Extents support for EXT4
13 *
14 * TODO:
15 * - ext4*_error() should be used in some situations
16 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
17 * - smart tree reduction
18 */
19
20#include <linux/fs.h>
21#include <linux/time.h>
22#include <linux/jbd2.h>
23#include <linux/highuid.h>
24#include <linux/pagemap.h>
25#include <linux/quotaops.h>
26#include <linux/string.h>
27#include <linux/slab.h>
28#include <linux/uaccess.h>
29#include <linux/fiemap.h>
30#include <linux/backing-dev.h>
31#include "ext4_jbd2.h"
32#include "ext4_extents.h"
33#include "xattr.h"
34
35#include <trace/events/ext4.h>
36
37/*
38 * used by extent splitting.
39 */
40#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
41 due to ENOSPC */
42#define EXT4_EXT_MARK_UNWRIT1 0x2 /* mark first half unwritten */
43#define EXT4_EXT_MARK_UNWRIT2 0x4 /* mark second half unwritten */
44
45#define EXT4_EXT_DATA_VALID1 0x8 /* first half contains valid data */
46#define EXT4_EXT_DATA_VALID2 0x10 /* second half contains valid data */
47
48static __le32 ext4_extent_block_csum(struct inode *inode,
49 struct ext4_extent_header *eh)
50{
51 struct ext4_inode_info *ei = EXT4_I(inode);
52 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
53 __u32 csum;
54
55 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
56 EXT4_EXTENT_TAIL_OFFSET(eh));
57 return cpu_to_le32(csum);
58}
59
60static int ext4_extent_block_csum_verify(struct inode *inode,
61 struct ext4_extent_header *eh)
62{
63 struct ext4_extent_tail *et;
64
65 if (!ext4_has_metadata_csum(inode->i_sb))
66 return 1;
67
68 et = find_ext4_extent_tail(eh);
69 if (et->et_checksum != ext4_extent_block_csum(inode, eh))
70 return 0;
71 return 1;
72}
73
74static void ext4_extent_block_csum_set(struct inode *inode,
75 struct ext4_extent_header *eh)
76{
77 struct ext4_extent_tail *et;
78
79 if (!ext4_has_metadata_csum(inode->i_sb))
80 return;
81
82 et = find_ext4_extent_tail(eh);
83 et->et_checksum = ext4_extent_block_csum(inode, eh);
84}
85
86static int ext4_split_extent(handle_t *handle,
87 struct inode *inode,
88 struct ext4_ext_path **ppath,
89 struct ext4_map_blocks *map,
90 int split_flag,
91 int flags);
92
93static int ext4_split_extent_at(handle_t *handle,
94 struct inode *inode,
95 struct ext4_ext_path **ppath,
96 ext4_lblk_t split,
97 int split_flag,
98 int flags);
99
100static int ext4_find_delayed_extent(struct inode *inode,
101 struct extent_status *newes);
102
103static int ext4_ext_truncate_extend_restart(handle_t *handle,
104 struct inode *inode,
105 int needed)
106{
107 int err;
108
109 if (!ext4_handle_valid(handle))
110 return 0;
111 if (handle->h_buffer_credits >= needed)
112 return 0;
113 /*
114 * If we need to extend the journal get a few extra blocks
115 * while we're at it for efficiency's sake.
116 */
117 needed += 3;
118 err = ext4_journal_extend(handle, needed - handle->h_buffer_credits);
119 if (err <= 0)
120 return err;
121 err = ext4_truncate_restart_trans(handle, inode, needed);
122 if (err == 0)
123 err = -EAGAIN;
124
125 return err;
126}
127
128/*
129 * could return:
130 * - EROFS
131 * - ENOMEM
132 */
133static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
134 struct ext4_ext_path *path)
135{
136 if (path->p_bh) {
137 /* path points to block */
138 BUFFER_TRACE(path->p_bh, "get_write_access");
139 return ext4_journal_get_write_access(handle, path->p_bh);
140 }
141 /* path points to leaf/index in inode body */
142 /* we use in-core data, no need to protect them */
143 return 0;
144}
145
146/*
147 * could return:
148 * - EROFS
149 * - ENOMEM
150 * - EIO
151 */
152int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
153 struct inode *inode, struct ext4_ext_path *path)
154{
155 int err;
156
157 WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
158 if (path->p_bh) {
159 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
160 /* path points to block */
161 err = __ext4_handle_dirty_metadata(where, line, handle,
162 inode, path->p_bh);
163 } else {
164 /* path points to leaf/index in inode body */
165 err = ext4_mark_inode_dirty(handle, inode);
166 }
167 return err;
168}
169
170static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
171 struct ext4_ext_path *path,
172 ext4_lblk_t block)
173{
174 if (path) {
175 int depth = path->p_depth;
176 struct ext4_extent *ex;
177
178 /*
179 * Try to predict block placement assuming that we are
180 * filling in a file which will eventually be
181 * non-sparse --- i.e., in the case of libbfd writing
182 * an ELF object sections out-of-order but in a way
183 * the eventually results in a contiguous object or
184 * executable file, or some database extending a table
185 * space file. However, this is actually somewhat
186 * non-ideal if we are writing a sparse file such as
187 * qemu or KVM writing a raw image file that is going
188 * to stay fairly sparse, since it will end up
189 * fragmenting the file system's free space. Maybe we
190 * should have some hueristics or some way to allow
191 * userspace to pass a hint to file system,
192 * especially if the latter case turns out to be
193 * common.
194 */
195 ex = path[depth].p_ext;
196 if (ex) {
197 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
198 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
199
200 if (block > ext_block)
201 return ext_pblk + (block - ext_block);
202 else
203 return ext_pblk - (ext_block - block);
204 }
205
206 /* it looks like index is empty;
207 * try to find starting block from index itself */
208 if (path[depth].p_bh)
209 return path[depth].p_bh->b_blocknr;
210 }
211
212 /* OK. use inode's group */
213 return ext4_inode_to_goal_block(inode);
214}
215
216/*
217 * Allocation for a meta data block
218 */
219static ext4_fsblk_t
220ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
221 struct ext4_ext_path *path,
222 struct ext4_extent *ex, int *err, unsigned int flags)
223{
224 ext4_fsblk_t goal, newblock;
225
226 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
227 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
228 NULL, err);
229 return newblock;
230}
231
232static inline int ext4_ext_space_block(struct inode *inode, int check)
233{
234 int size;
235
236 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
237 / sizeof(struct ext4_extent);
238#ifdef AGGRESSIVE_TEST
239 if (!check && size > 6)
240 size = 6;
241#endif
242 return size;
243}
244
245static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
246{
247 int size;
248
249 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
250 / sizeof(struct ext4_extent_idx);
251#ifdef AGGRESSIVE_TEST
252 if (!check && size > 5)
253 size = 5;
254#endif
255 return size;
256}
257
258static inline int ext4_ext_space_root(struct inode *inode, int check)
259{
260 int size;
261
262 size = sizeof(EXT4_I(inode)->i_data);
263 size -= sizeof(struct ext4_extent_header);
264 size /= sizeof(struct ext4_extent);
265#ifdef AGGRESSIVE_TEST
266 if (!check && size > 3)
267 size = 3;
268#endif
269 return size;
270}
271
272static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
273{
274 int size;
275
276 size = sizeof(EXT4_I(inode)->i_data);
277 size -= sizeof(struct ext4_extent_header);
278 size /= sizeof(struct ext4_extent_idx);
279#ifdef AGGRESSIVE_TEST
280 if (!check && size > 4)
281 size = 4;
282#endif
283 return size;
284}
285
286static inline int
287ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
288 struct ext4_ext_path **ppath, ext4_lblk_t lblk,
289 int nofail)
290{
291 struct ext4_ext_path *path = *ppath;
292 int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
293
294 return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
295 EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
296 EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
297 (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
298}
299
300/*
301 * Calculate the number of metadata blocks needed
302 * to allocate @blocks
303 * Worse case is one block per extent
304 */
305int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
306{
307 struct ext4_inode_info *ei = EXT4_I(inode);
308 int idxs;
309
310 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
311 / sizeof(struct ext4_extent_idx));
312
313 /*
314 * If the new delayed allocation block is contiguous with the
315 * previous da block, it can share index blocks with the
316 * previous block, so we only need to allocate a new index
317 * block every idxs leaf blocks. At ldxs**2 blocks, we need
318 * an additional index block, and at ldxs**3 blocks, yet
319 * another index blocks.
320 */
321 if (ei->i_da_metadata_calc_len &&
322 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
323 int num = 0;
324
325 if ((ei->i_da_metadata_calc_len % idxs) == 0)
326 num++;
327 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
328 num++;
329 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
330 num++;
331 ei->i_da_metadata_calc_len = 0;
332 } else
333 ei->i_da_metadata_calc_len++;
334 ei->i_da_metadata_calc_last_lblock++;
335 return num;
336 }
337
338 /*
339 * In the worst case we need a new set of index blocks at
340 * every level of the inode's extent tree.
341 */
342 ei->i_da_metadata_calc_len = 1;
343 ei->i_da_metadata_calc_last_lblock = lblock;
344 return ext_depth(inode) + 1;
345}
346
347static int
348ext4_ext_max_entries(struct inode *inode, int depth)
349{
350 int max;
351
352 if (depth == ext_depth(inode)) {
353 if (depth == 0)
354 max = ext4_ext_space_root(inode, 1);
355 else
356 max = ext4_ext_space_root_idx(inode, 1);
357 } else {
358 if (depth == 0)
359 max = ext4_ext_space_block(inode, 1);
360 else
361 max = ext4_ext_space_block_idx(inode, 1);
362 }
363
364 return max;
365}
366
367static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
368{
369 ext4_fsblk_t block = ext4_ext_pblock(ext);
370 int len = ext4_ext_get_actual_len(ext);
371 ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
372
373 /*
374 * We allow neither:
375 * - zero length
376 * - overflow/wrap-around
377 */
378 if (lblock + len <= lblock)
379 return 0;
380 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
381}
382
383static int ext4_valid_extent_idx(struct inode *inode,
384 struct ext4_extent_idx *ext_idx)
385{
386 ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
387
388 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
389}
390
391static int ext4_valid_extent_entries(struct inode *inode,
392 struct ext4_extent_header *eh,
393 int depth)
394{
395 unsigned short entries;
396 if (eh->eh_entries == 0)
397 return 1;
398
399 entries = le16_to_cpu(eh->eh_entries);
400
401 if (depth == 0) {
402 /* leaf entries */
403 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
404 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
405 ext4_fsblk_t pblock = 0;
406 ext4_lblk_t lblock = 0;
407 ext4_lblk_t prev = 0;
408 int len = 0;
409 while (entries) {
410 if (!ext4_valid_extent(inode, ext))
411 return 0;
412
413 /* Check for overlapping extents */
414 lblock = le32_to_cpu(ext->ee_block);
415 len = ext4_ext_get_actual_len(ext);
416 if ((lblock <= prev) && prev) {
417 pblock = ext4_ext_pblock(ext);
418 es->s_last_error_block = cpu_to_le64(pblock);
419 return 0;
420 }
421 ext++;
422 entries--;
423 prev = lblock + len - 1;
424 }
425 } else {
426 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
427 while (entries) {
428 if (!ext4_valid_extent_idx(inode, ext_idx))
429 return 0;
430 ext_idx++;
431 entries--;
432 }
433 }
434 return 1;
435}
436
437static int __ext4_ext_check(const char *function, unsigned int line,
438 struct inode *inode, struct ext4_extent_header *eh,
439 int depth, ext4_fsblk_t pblk)
440{
441 const char *error_msg;
442 int max = 0, err = -EFSCORRUPTED;
443
444 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
445 error_msg = "invalid magic";
446 goto corrupted;
447 }
448 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
449 error_msg = "unexpected eh_depth";
450 goto corrupted;
451 }
452 if (unlikely(eh->eh_max == 0)) {
453 error_msg = "invalid eh_max";
454 goto corrupted;
455 }
456 max = ext4_ext_max_entries(inode, depth);
457 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
458 error_msg = "too large eh_max";
459 goto corrupted;
460 }
461 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
462 error_msg = "invalid eh_entries";
463 goto corrupted;
464 }
465 if (!ext4_valid_extent_entries(inode, eh, depth)) {
466 error_msg = "invalid extent entries";
467 goto corrupted;
468 }
469 if (unlikely(depth > 32)) {
470 error_msg = "too large eh_depth";
471 goto corrupted;
472 }
473 /* Verify checksum on non-root extent tree nodes */
474 if (ext_depth(inode) != depth &&
475 !ext4_extent_block_csum_verify(inode, eh)) {
476 error_msg = "extent tree corrupted";
477 err = -EFSBADCRC;
478 goto corrupted;
479 }
480 return 0;
481
482corrupted:
483 ext4_error_inode(inode, function, line, 0,
484 "pblk %llu bad header/extent: %s - magic %x, "
485 "entries %u, max %u(%u), depth %u(%u)",
486 (unsigned long long) pblk, error_msg,
487 le16_to_cpu(eh->eh_magic),
488 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
489 max, le16_to_cpu(eh->eh_depth), depth);
490 return err;
491}
492
493#define ext4_ext_check(inode, eh, depth, pblk) \
494 __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
495
496int ext4_ext_check_inode(struct inode *inode)
497{
498 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
499}
500
501static struct buffer_head *
502__read_extent_tree_block(const char *function, unsigned int line,
503 struct inode *inode, ext4_fsblk_t pblk, int depth,
504 int flags)
505{
506 struct buffer_head *bh;
507 int err;
508
509 bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
510 if (unlikely(!bh))
511 return ERR_PTR(-ENOMEM);
512
513 if (!bh_uptodate_or_lock(bh)) {
514 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
515 err = bh_submit_read(bh);
516 if (err < 0)
517 goto errout;
518 }
519 if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
520 return bh;
521 err = __ext4_ext_check(function, line, inode,
522 ext_block_hdr(bh), depth, pblk);
523 if (err)
524 goto errout;
525 set_buffer_verified(bh);
526 /*
527 * If this is a leaf block, cache all of its entries
528 */
529 if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
530 struct ext4_extent_header *eh = ext_block_hdr(bh);
531 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
532 ext4_lblk_t prev = 0;
533 int i;
534
535 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
536 unsigned int status = EXTENT_STATUS_WRITTEN;
537 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
538 int len = ext4_ext_get_actual_len(ex);
539
540 if (prev && (prev != lblk))
541 ext4_es_cache_extent(inode, prev,
542 lblk - prev, ~0,
543 EXTENT_STATUS_HOLE);
544
545 if (ext4_ext_is_unwritten(ex))
546 status = EXTENT_STATUS_UNWRITTEN;
547 ext4_es_cache_extent(inode, lblk, len,
548 ext4_ext_pblock(ex), status);
549 prev = lblk + len;
550 }
551 }
552 return bh;
553errout:
554 put_bh(bh);
555 return ERR_PTR(err);
556
557}
558
559#define read_extent_tree_block(inode, pblk, depth, flags) \
560 __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \
561 (depth), (flags))
562
563/*
564 * This function is called to cache a file's extent information in the
565 * extent status tree
566 */
567int ext4_ext_precache(struct inode *inode)
568{
569 struct ext4_inode_info *ei = EXT4_I(inode);
570 struct ext4_ext_path *path = NULL;
571 struct buffer_head *bh;
572 int i = 0, depth, ret = 0;
573
574 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
575 return 0; /* not an extent-mapped inode */
576
577 down_read(&ei->i_data_sem);
578 depth = ext_depth(inode);
579
580 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
581 GFP_NOFS);
582 if (path == NULL) {
583 up_read(&ei->i_data_sem);
584 return -ENOMEM;
585 }
586
587 /* Don't cache anything if there are no external extent blocks */
588 if (depth == 0)
589 goto out;
590 path[0].p_hdr = ext_inode_hdr(inode);
591 ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
592 if (ret)
593 goto out;
594 path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
595 while (i >= 0) {
596 /*
597 * If this is a leaf block or we've reached the end of
598 * the index block, go up
599 */
600 if ((i == depth) ||
601 path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
602 brelse(path[i].p_bh);
603 path[i].p_bh = NULL;
604 i--;
605 continue;
606 }
607 bh = read_extent_tree_block(inode,
608 ext4_idx_pblock(path[i].p_idx++),
609 depth - i - 1,
610 EXT4_EX_FORCE_CACHE);
611 if (IS_ERR(bh)) {
612 ret = PTR_ERR(bh);
613 break;
614 }
615 i++;
616 path[i].p_bh = bh;
617 path[i].p_hdr = ext_block_hdr(bh);
618 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
619 }
620 ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
621out:
622 up_read(&ei->i_data_sem);
623 ext4_ext_drop_refs(path);
624 kfree(path);
625 return ret;
626}
627
628#ifdef EXT_DEBUG
629static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
630{
631 int k, l = path->p_depth;
632
633 ext_debug("path:");
634 for (k = 0; k <= l; k++, path++) {
635 if (path->p_idx) {
636 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
637 ext4_idx_pblock(path->p_idx));
638 } else if (path->p_ext) {
639 ext_debug(" %d:[%d]%d:%llu ",
640 le32_to_cpu(path->p_ext->ee_block),
641 ext4_ext_is_unwritten(path->p_ext),
642 ext4_ext_get_actual_len(path->p_ext),
643 ext4_ext_pblock(path->p_ext));
644 } else
645 ext_debug(" []");
646 }
647 ext_debug("\n");
648}
649
650static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
651{
652 int depth = ext_depth(inode);
653 struct ext4_extent_header *eh;
654 struct ext4_extent *ex;
655 int i;
656
657 if (!path)
658 return;
659
660 eh = path[depth].p_hdr;
661 ex = EXT_FIRST_EXTENT(eh);
662
663 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
664
665 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
666 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
667 ext4_ext_is_unwritten(ex),
668 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
669 }
670 ext_debug("\n");
671}
672
673static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
674 ext4_fsblk_t newblock, int level)
675{
676 int depth = ext_depth(inode);
677 struct ext4_extent *ex;
678
679 if (depth != level) {
680 struct ext4_extent_idx *idx;
681 idx = path[level].p_idx;
682 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
683 ext_debug("%d: move %d:%llu in new index %llu\n", level,
684 le32_to_cpu(idx->ei_block),
685 ext4_idx_pblock(idx),
686 newblock);
687 idx++;
688 }
689
690 return;
691 }
692
693 ex = path[depth].p_ext;
694 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
695 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
696 le32_to_cpu(ex->ee_block),
697 ext4_ext_pblock(ex),
698 ext4_ext_is_unwritten(ex),
699 ext4_ext_get_actual_len(ex),
700 newblock);
701 ex++;
702 }
703}
704
705#else
706#define ext4_ext_show_path(inode, path)
707#define ext4_ext_show_leaf(inode, path)
708#define ext4_ext_show_move(inode, path, newblock, level)
709#endif
710
711void ext4_ext_drop_refs(struct ext4_ext_path *path)
712{
713 int depth, i;
714
715 if (!path)
716 return;
717 depth = path->p_depth;
718 for (i = 0; i <= depth; i++, path++)
719 if (path->p_bh) {
720 brelse(path->p_bh);
721 path->p_bh = NULL;
722 }
723}
724
725/*
726 * ext4_ext_binsearch_idx:
727 * binary search for the closest index of the given block
728 * the header must be checked before calling this
729 */
730static void
731ext4_ext_binsearch_idx(struct inode *inode,
732 struct ext4_ext_path *path, ext4_lblk_t block)
733{
734 struct ext4_extent_header *eh = path->p_hdr;
735 struct ext4_extent_idx *r, *l, *m;
736
737
738 ext_debug("binsearch for %u(idx): ", block);
739
740 l = EXT_FIRST_INDEX(eh) + 1;
741 r = EXT_LAST_INDEX(eh);
742 while (l <= r) {
743 m = l + (r - l) / 2;
744 if (block < le32_to_cpu(m->ei_block))
745 r = m - 1;
746 else
747 l = m + 1;
748 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
749 m, le32_to_cpu(m->ei_block),
750 r, le32_to_cpu(r->ei_block));
751 }
752
753 path->p_idx = l - 1;
754 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
755 ext4_idx_pblock(path->p_idx));
756
757#ifdef CHECK_BINSEARCH
758 {
759 struct ext4_extent_idx *chix, *ix;
760 int k;
761
762 chix = ix = EXT_FIRST_INDEX(eh);
763 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
764 if (k != 0 &&
765 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
766 printk(KERN_DEBUG "k=%d, ix=0x%p, "
767 "first=0x%p\n", k,
768 ix, EXT_FIRST_INDEX(eh));
769 printk(KERN_DEBUG "%u <= %u\n",
770 le32_to_cpu(ix->ei_block),
771 le32_to_cpu(ix[-1].ei_block));
772 }
773 BUG_ON(k && le32_to_cpu(ix->ei_block)
774 <= le32_to_cpu(ix[-1].ei_block));
775 if (block < le32_to_cpu(ix->ei_block))
776 break;
777 chix = ix;
778 }
779 BUG_ON(chix != path->p_idx);
780 }
781#endif
782
783}
784
785/*
786 * ext4_ext_binsearch:
787 * binary search for closest extent of the given block
788 * the header must be checked before calling this
789 */
790static void
791ext4_ext_binsearch(struct inode *inode,
792 struct ext4_ext_path *path, ext4_lblk_t block)
793{
794 struct ext4_extent_header *eh = path->p_hdr;
795 struct ext4_extent *r, *l, *m;
796
797 if (eh->eh_entries == 0) {
798 /*
799 * this leaf is empty:
800 * we get such a leaf in split/add case
801 */
802 return;
803 }
804
805 ext_debug("binsearch for %u: ", block);
806
807 l = EXT_FIRST_EXTENT(eh) + 1;
808 r = EXT_LAST_EXTENT(eh);
809
810 while (l <= r) {
811 m = l + (r - l) / 2;
812 if (block < le32_to_cpu(m->ee_block))
813 r = m - 1;
814 else
815 l = m + 1;
816 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
817 m, le32_to_cpu(m->ee_block),
818 r, le32_to_cpu(r->ee_block));
819 }
820
821 path->p_ext = l - 1;
822 ext_debug(" -> %d:%llu:[%d]%d ",
823 le32_to_cpu(path->p_ext->ee_block),
824 ext4_ext_pblock(path->p_ext),
825 ext4_ext_is_unwritten(path->p_ext),
826 ext4_ext_get_actual_len(path->p_ext));
827
828#ifdef CHECK_BINSEARCH
829 {
830 struct ext4_extent *chex, *ex;
831 int k;
832
833 chex = ex = EXT_FIRST_EXTENT(eh);
834 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
835 BUG_ON(k && le32_to_cpu(ex->ee_block)
836 <= le32_to_cpu(ex[-1].ee_block));
837 if (block < le32_to_cpu(ex->ee_block))
838 break;
839 chex = ex;
840 }
841 BUG_ON(chex != path->p_ext);
842 }
843#endif
844
845}
846
847int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
848{
849 struct ext4_extent_header *eh;
850
851 eh = ext_inode_hdr(inode);
852 eh->eh_depth = 0;
853 eh->eh_entries = 0;
854 eh->eh_magic = EXT4_EXT_MAGIC;
855 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
856 ext4_mark_inode_dirty(handle, inode);
857 return 0;
858}
859
860struct ext4_ext_path *
861ext4_find_extent(struct inode *inode, ext4_lblk_t block,
862 struct ext4_ext_path **orig_path, int flags)
863{
864 struct ext4_extent_header *eh;
865 struct buffer_head *bh;
866 struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
867 short int depth, i, ppos = 0;
868 int ret;
869
870 eh = ext_inode_hdr(inode);
871 depth = ext_depth(inode);
872
873 if (path) {
874 ext4_ext_drop_refs(path);
875 if (depth > path[0].p_maxdepth) {
876 kfree(path);
877 *orig_path = path = NULL;
878 }
879 }
880 if (!path) {
881 /* account possible depth increase */
882 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
883 GFP_NOFS);
884 if (unlikely(!path))
885 return ERR_PTR(-ENOMEM);
886 path[0].p_maxdepth = depth + 1;
887 }
888 path[0].p_hdr = eh;
889 path[0].p_bh = NULL;
890
891 i = depth;
892 /* walk through the tree */
893 while (i) {
894 ext_debug("depth %d: num %d, max %d\n",
895 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
896
897 ext4_ext_binsearch_idx(inode, path + ppos, block);
898 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
899 path[ppos].p_depth = i;
900 path[ppos].p_ext = NULL;
901
902 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
903 flags);
904 if (IS_ERR(bh)) {
905 ret = PTR_ERR(bh);
906 goto err;
907 }
908
909 eh = ext_block_hdr(bh);
910 ppos++;
911 path[ppos].p_bh = bh;
912 path[ppos].p_hdr = eh;
913 }
914
915 path[ppos].p_depth = i;
916 path[ppos].p_ext = NULL;
917 path[ppos].p_idx = NULL;
918
919 /* find extent */
920 ext4_ext_binsearch(inode, path + ppos, block);
921 /* if not an empty leaf */
922 if (path[ppos].p_ext)
923 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
924
925 ext4_ext_show_path(inode, path);
926
927 return path;
928
929err:
930 ext4_ext_drop_refs(path);
931 kfree(path);
932 if (orig_path)
933 *orig_path = NULL;
934 return ERR_PTR(ret);
935}
936
937/*
938 * ext4_ext_insert_index:
939 * insert new index [@logical;@ptr] into the block at @curp;
940 * check where to insert: before @curp or after @curp
941 */
942static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
943 struct ext4_ext_path *curp,
944 int logical, ext4_fsblk_t ptr)
945{
946 struct ext4_extent_idx *ix;
947 int len, err;
948
949 err = ext4_ext_get_access(handle, inode, curp);
950 if (err)
951 return err;
952
953 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
954 EXT4_ERROR_INODE(inode,
955 "logical %d == ei_block %d!",
956 logical, le32_to_cpu(curp->p_idx->ei_block));
957 return -EFSCORRUPTED;
958 }
959
960 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
961 >= le16_to_cpu(curp->p_hdr->eh_max))) {
962 EXT4_ERROR_INODE(inode,
963 "eh_entries %d >= eh_max %d!",
964 le16_to_cpu(curp->p_hdr->eh_entries),
965 le16_to_cpu(curp->p_hdr->eh_max));
966 return -EFSCORRUPTED;
967 }
968
969 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
970 /* insert after */
971 ext_debug("insert new index %d after: %llu\n", logical, ptr);
972 ix = curp->p_idx + 1;
973 } else {
974 /* insert before */
975 ext_debug("insert new index %d before: %llu\n", logical, ptr);
976 ix = curp->p_idx;
977 }
978
979 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
980 BUG_ON(len < 0);
981 if (len > 0) {
982 ext_debug("insert new index %d: "
983 "move %d indices from 0x%p to 0x%p\n",
984 logical, len, ix, ix + 1);
985 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
986 }
987
988 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
989 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
990 return -EFSCORRUPTED;
991 }
992
993 ix->ei_block = cpu_to_le32(logical);
994 ext4_idx_store_pblock(ix, ptr);
995 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
996
997 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
998 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
999 return -EFSCORRUPTED;
1000 }
1001
1002 err = ext4_ext_dirty(handle, inode, curp);
1003 ext4_std_error(inode->i_sb, err);
1004
1005 return err;
1006}
1007
1008/*
1009 * ext4_ext_split:
1010 * inserts new subtree into the path, using free index entry
1011 * at depth @at:
1012 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1013 * - makes decision where to split
1014 * - moves remaining extents and index entries (right to the split point)
1015 * into the newly allocated blocks
1016 * - initializes subtree
1017 */
1018static int ext4_ext_split(handle_t *handle, struct inode *inode,
1019 unsigned int flags,
1020 struct ext4_ext_path *path,
1021 struct ext4_extent *newext, int at)
1022{
1023 struct buffer_head *bh = NULL;
1024 int depth = ext_depth(inode);
1025 struct ext4_extent_header *neh;
1026 struct ext4_extent_idx *fidx;
1027 int i = at, k, m, a;
1028 ext4_fsblk_t newblock, oldblock;
1029 __le32 border;
1030 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1031 int err = 0;
1032
1033 /* make decision: where to split? */
1034 /* FIXME: now decision is simplest: at current extent */
1035
1036 /* if current leaf will be split, then we should use
1037 * border from split point */
1038 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1039 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1040 return -EFSCORRUPTED;
1041 }
1042 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1043 border = path[depth].p_ext[1].ee_block;
1044 ext_debug("leaf will be split."
1045 " next leaf starts at %d\n",
1046 le32_to_cpu(border));
1047 } else {
1048 border = newext->ee_block;
1049 ext_debug("leaf will be added."
1050 " next leaf starts at %d\n",
1051 le32_to_cpu(border));
1052 }
1053
1054 /*
1055 * If error occurs, then we break processing
1056 * and mark filesystem read-only. index won't
1057 * be inserted and tree will be in consistent
1058 * state. Next mount will repair buffers too.
1059 */
1060
1061 /*
1062 * Get array to track all allocated blocks.
1063 * We need this to handle errors and free blocks
1064 * upon them.
1065 */
1066 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1067 if (!ablocks)
1068 return -ENOMEM;
1069
1070 /* allocate all needed blocks */
1071 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1072 for (a = 0; a < depth - at; a++) {
1073 newblock = ext4_ext_new_meta_block(handle, inode, path,
1074 newext, &err, flags);
1075 if (newblock == 0)
1076 goto cleanup;
1077 ablocks[a] = newblock;
1078 }
1079
1080 /* initialize new leaf */
1081 newblock = ablocks[--a];
1082 if (unlikely(newblock == 0)) {
1083 EXT4_ERROR_INODE(inode, "newblock == 0!");
1084 err = -EFSCORRUPTED;
1085 goto cleanup;
1086 }
1087 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1088 if (unlikely(!bh)) {
1089 err = -ENOMEM;
1090 goto cleanup;
1091 }
1092 lock_buffer(bh);
1093
1094 err = ext4_journal_get_create_access(handle, bh);
1095 if (err)
1096 goto cleanup;
1097
1098 neh = ext_block_hdr(bh);
1099 neh->eh_entries = 0;
1100 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1101 neh->eh_magic = EXT4_EXT_MAGIC;
1102 neh->eh_depth = 0;
1103
1104 /* move remainder of path[depth] to the new leaf */
1105 if (unlikely(path[depth].p_hdr->eh_entries !=
1106 path[depth].p_hdr->eh_max)) {
1107 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1108 path[depth].p_hdr->eh_entries,
1109 path[depth].p_hdr->eh_max);
1110 err = -EFSCORRUPTED;
1111 goto cleanup;
1112 }
1113 /* start copy from next extent */
1114 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1115 ext4_ext_show_move(inode, path, newblock, depth);
1116 if (m) {
1117 struct ext4_extent *ex;
1118 ex = EXT_FIRST_EXTENT(neh);
1119 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1120 le16_add_cpu(&neh->eh_entries, m);
1121 }
1122
1123 ext4_extent_block_csum_set(inode, neh);
1124 set_buffer_uptodate(bh);
1125 unlock_buffer(bh);
1126
1127 err = ext4_handle_dirty_metadata(handle, inode, bh);
1128 if (err)
1129 goto cleanup;
1130 brelse(bh);
1131 bh = NULL;
1132
1133 /* correct old leaf */
1134 if (m) {
1135 err = ext4_ext_get_access(handle, inode, path + depth);
1136 if (err)
1137 goto cleanup;
1138 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1139 err = ext4_ext_dirty(handle, inode, path + depth);
1140 if (err)
1141 goto cleanup;
1142
1143 }
1144
1145 /* create intermediate indexes */
1146 k = depth - at - 1;
1147 if (unlikely(k < 0)) {
1148 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1149 err = -EFSCORRUPTED;
1150 goto cleanup;
1151 }
1152 if (k)
1153 ext_debug("create %d intermediate indices\n", k);
1154 /* insert new index into current index block */
1155 /* current depth stored in i var */
1156 i = depth - 1;
1157 while (k--) {
1158 oldblock = newblock;
1159 newblock = ablocks[--a];
1160 bh = sb_getblk(inode->i_sb, newblock);
1161 if (unlikely(!bh)) {
1162 err = -ENOMEM;
1163 goto cleanup;
1164 }
1165 lock_buffer(bh);
1166
1167 err = ext4_journal_get_create_access(handle, bh);
1168 if (err)
1169 goto cleanup;
1170
1171 neh = ext_block_hdr(bh);
1172 neh->eh_entries = cpu_to_le16(1);
1173 neh->eh_magic = EXT4_EXT_MAGIC;
1174 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1175 neh->eh_depth = cpu_to_le16(depth - i);
1176 fidx = EXT_FIRST_INDEX(neh);
1177 fidx->ei_block = border;
1178 ext4_idx_store_pblock(fidx, oldblock);
1179
1180 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1181 i, newblock, le32_to_cpu(border), oldblock);
1182
1183 /* move remainder of path[i] to the new index block */
1184 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1185 EXT_LAST_INDEX(path[i].p_hdr))) {
1186 EXT4_ERROR_INODE(inode,
1187 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1188 le32_to_cpu(path[i].p_ext->ee_block));
1189 err = -EFSCORRUPTED;
1190 goto cleanup;
1191 }
1192 /* start copy indexes */
1193 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1194 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1195 EXT_MAX_INDEX(path[i].p_hdr));
1196 ext4_ext_show_move(inode, path, newblock, i);
1197 if (m) {
1198 memmove(++fidx, path[i].p_idx,
1199 sizeof(struct ext4_extent_idx) * m);
1200 le16_add_cpu(&neh->eh_entries, m);
1201 }
1202 ext4_extent_block_csum_set(inode, neh);
1203 set_buffer_uptodate(bh);
1204 unlock_buffer(bh);
1205
1206 err = ext4_handle_dirty_metadata(handle, inode, bh);
1207 if (err)
1208 goto cleanup;
1209 brelse(bh);
1210 bh = NULL;
1211
1212 /* correct old index */
1213 if (m) {
1214 err = ext4_ext_get_access(handle, inode, path + i);
1215 if (err)
1216 goto cleanup;
1217 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1218 err = ext4_ext_dirty(handle, inode, path + i);
1219 if (err)
1220 goto cleanup;
1221 }
1222
1223 i--;
1224 }
1225
1226 /* insert new index */
1227 err = ext4_ext_insert_index(handle, inode, path + at,
1228 le32_to_cpu(border), newblock);
1229
1230cleanup:
1231 if (bh) {
1232 if (buffer_locked(bh))
1233 unlock_buffer(bh);
1234 brelse(bh);
1235 }
1236
1237 if (err) {
1238 /* free all allocated blocks in error case */
1239 for (i = 0; i < depth; i++) {
1240 if (!ablocks[i])
1241 continue;
1242 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1243 EXT4_FREE_BLOCKS_METADATA);
1244 }
1245 }
1246 kfree(ablocks);
1247
1248 return err;
1249}
1250
1251/*
1252 * ext4_ext_grow_indepth:
1253 * implements tree growing procedure:
1254 * - allocates new block
1255 * - moves top-level data (index block or leaf) into the new block
1256 * - initializes new top-level, creating index that points to the
1257 * just created block
1258 */
1259static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1260 unsigned int flags)
1261{
1262 struct ext4_extent_header *neh;
1263 struct buffer_head *bh;
1264 ext4_fsblk_t newblock, goal = 0;
1265 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1266 int err = 0;
1267
1268 /* Try to prepend new index to old one */
1269 if (ext_depth(inode))
1270 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1271 if (goal > le32_to_cpu(es->s_first_data_block)) {
1272 flags |= EXT4_MB_HINT_TRY_GOAL;
1273 goal--;
1274 } else
1275 goal = ext4_inode_to_goal_block(inode);
1276 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1277 NULL, &err);
1278 if (newblock == 0)
1279 return err;
1280
1281 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1282 if (unlikely(!bh))
1283 return -ENOMEM;
1284 lock_buffer(bh);
1285
1286 err = ext4_journal_get_create_access(handle, bh);
1287 if (err) {
1288 unlock_buffer(bh);
1289 goto out;
1290 }
1291
1292 /* move top-level index/leaf into new block */
1293 memmove(bh->b_data, EXT4_I(inode)->i_data,
1294 sizeof(EXT4_I(inode)->i_data));
1295
1296 /* set size of new block */
1297 neh = ext_block_hdr(bh);
1298 /* old root could have indexes or leaves
1299 * so calculate e_max right way */
1300 if (ext_depth(inode))
1301 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1302 else
1303 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1304 neh->eh_magic = EXT4_EXT_MAGIC;
1305 ext4_extent_block_csum_set(inode, neh);
1306 set_buffer_uptodate(bh);
1307 unlock_buffer(bh);
1308
1309 err = ext4_handle_dirty_metadata(handle, inode, bh);
1310 if (err)
1311 goto out;
1312
1313 /* Update top-level index: num,max,pointer */
1314 neh = ext_inode_hdr(inode);
1315 neh->eh_entries = cpu_to_le16(1);
1316 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1317 if (neh->eh_depth == 0) {
1318 /* Root extent block becomes index block */
1319 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1320 EXT_FIRST_INDEX(neh)->ei_block =
1321 EXT_FIRST_EXTENT(neh)->ee_block;
1322 }
1323 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1324 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1325 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1326 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1327
1328 le16_add_cpu(&neh->eh_depth, 1);
1329 ext4_mark_inode_dirty(handle, inode);
1330out:
1331 brelse(bh);
1332
1333 return err;
1334}
1335
1336/*
1337 * ext4_ext_create_new_leaf:
1338 * finds empty index and adds new leaf.
1339 * if no free index is found, then it requests in-depth growing.
1340 */
1341static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1342 unsigned int mb_flags,
1343 unsigned int gb_flags,
1344 struct ext4_ext_path **ppath,
1345 struct ext4_extent *newext)
1346{
1347 struct ext4_ext_path *path = *ppath;
1348 struct ext4_ext_path *curp;
1349 int depth, i, err = 0;
1350
1351repeat:
1352 i = depth = ext_depth(inode);
1353
1354 /* walk up to the tree and look for free index entry */
1355 curp = path + depth;
1356 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1357 i--;
1358 curp--;
1359 }
1360
1361 /* we use already allocated block for index block,
1362 * so subsequent data blocks should be contiguous */
1363 if (EXT_HAS_FREE_INDEX(curp)) {
1364 /* if we found index with free entry, then use that
1365 * entry: create all needed subtree and add new leaf */
1366 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1367 if (err)
1368 goto out;
1369
1370 /* refill path */
1371 path = ext4_find_extent(inode,
1372 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1373 ppath, gb_flags);
1374 if (IS_ERR(path))
1375 err = PTR_ERR(path);
1376 } else {
1377 /* tree is full, time to grow in depth */
1378 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1379 if (err)
1380 goto out;
1381
1382 /* refill path */
1383 path = ext4_find_extent(inode,
1384 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1385 ppath, gb_flags);
1386 if (IS_ERR(path)) {
1387 err = PTR_ERR(path);
1388 goto out;
1389 }
1390
1391 /*
1392 * only first (depth 0 -> 1) produces free space;
1393 * in all other cases we have to split the grown tree
1394 */
1395 depth = ext_depth(inode);
1396 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1397 /* now we need to split */
1398 goto repeat;
1399 }
1400 }
1401
1402out:
1403 return err;
1404}
1405
1406/*
1407 * search the closest allocated block to the left for *logical
1408 * and returns it at @logical + it's physical address at @phys
1409 * if *logical is the smallest allocated block, the function
1410 * returns 0 at @phys
1411 * return value contains 0 (success) or error code
1412 */
1413static int ext4_ext_search_left(struct inode *inode,
1414 struct ext4_ext_path *path,
1415 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1416{
1417 struct ext4_extent_idx *ix;
1418 struct ext4_extent *ex;
1419 int depth, ee_len;
1420
1421 if (unlikely(path == NULL)) {
1422 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1423 return -EFSCORRUPTED;
1424 }
1425 depth = path->p_depth;
1426 *phys = 0;
1427
1428 if (depth == 0 && path->p_ext == NULL)
1429 return 0;
1430
1431 /* usually extent in the path covers blocks smaller
1432 * then *logical, but it can be that extent is the
1433 * first one in the file */
1434
1435 ex = path[depth].p_ext;
1436 ee_len = ext4_ext_get_actual_len(ex);
1437 if (*logical < le32_to_cpu(ex->ee_block)) {
1438 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1439 EXT4_ERROR_INODE(inode,
1440 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1441 *logical, le32_to_cpu(ex->ee_block));
1442 return -EFSCORRUPTED;
1443 }
1444 while (--depth >= 0) {
1445 ix = path[depth].p_idx;
1446 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1447 EXT4_ERROR_INODE(inode,
1448 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1449 ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1450 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1451 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1452 depth);
1453 return -EFSCORRUPTED;
1454 }
1455 }
1456 return 0;
1457 }
1458
1459 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1460 EXT4_ERROR_INODE(inode,
1461 "logical %d < ee_block %d + ee_len %d!",
1462 *logical, le32_to_cpu(ex->ee_block), ee_len);
1463 return -EFSCORRUPTED;
1464 }
1465
1466 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1467 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1468 return 0;
1469}
1470
1471/*
1472 * search the closest allocated block to the right for *logical
1473 * and returns it at @logical + it's physical address at @phys
1474 * if *logical is the largest allocated block, the function
1475 * returns 0 at @phys
1476 * return value contains 0 (success) or error code
1477 */
1478static int ext4_ext_search_right(struct inode *inode,
1479 struct ext4_ext_path *path,
1480 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1481 struct ext4_extent **ret_ex)
1482{
1483 struct buffer_head *bh = NULL;
1484 struct ext4_extent_header *eh;
1485 struct ext4_extent_idx *ix;
1486 struct ext4_extent *ex;
1487 ext4_fsblk_t block;
1488 int depth; /* Note, NOT eh_depth; depth from top of tree */
1489 int ee_len;
1490
1491 if (unlikely(path == NULL)) {
1492 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1493 return -EFSCORRUPTED;
1494 }
1495 depth = path->p_depth;
1496 *phys = 0;
1497
1498 if (depth == 0 && path->p_ext == NULL)
1499 return 0;
1500
1501 /* usually extent in the path covers blocks smaller
1502 * then *logical, but it can be that extent is the
1503 * first one in the file */
1504
1505 ex = path[depth].p_ext;
1506 ee_len = ext4_ext_get_actual_len(ex);
1507 if (*logical < le32_to_cpu(ex->ee_block)) {
1508 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1509 EXT4_ERROR_INODE(inode,
1510 "first_extent(path[%d].p_hdr) != ex",
1511 depth);
1512 return -EFSCORRUPTED;
1513 }
1514 while (--depth >= 0) {
1515 ix = path[depth].p_idx;
1516 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1517 EXT4_ERROR_INODE(inode,
1518 "ix != EXT_FIRST_INDEX *logical %d!",
1519 *logical);
1520 return -EFSCORRUPTED;
1521 }
1522 }
1523 goto found_extent;
1524 }
1525
1526 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1527 EXT4_ERROR_INODE(inode,
1528 "logical %d < ee_block %d + ee_len %d!",
1529 *logical, le32_to_cpu(ex->ee_block), ee_len);
1530 return -EFSCORRUPTED;
1531 }
1532
1533 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1534 /* next allocated block in this leaf */
1535 ex++;
1536 goto found_extent;
1537 }
1538
1539 /* go up and search for index to the right */
1540 while (--depth >= 0) {
1541 ix = path[depth].p_idx;
1542 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1543 goto got_index;
1544 }
1545
1546 /* we've gone up to the root and found no index to the right */
1547 return 0;
1548
1549got_index:
1550 /* we've found index to the right, let's
1551 * follow it and find the closest allocated
1552 * block to the right */
1553 ix++;
1554 block = ext4_idx_pblock(ix);
1555 while (++depth < path->p_depth) {
1556 /* subtract from p_depth to get proper eh_depth */
1557 bh = read_extent_tree_block(inode, block,
1558 path->p_depth - depth, 0);
1559 if (IS_ERR(bh))
1560 return PTR_ERR(bh);
1561 eh = ext_block_hdr(bh);
1562 ix = EXT_FIRST_INDEX(eh);
1563 block = ext4_idx_pblock(ix);
1564 put_bh(bh);
1565 }
1566
1567 bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1568 if (IS_ERR(bh))
1569 return PTR_ERR(bh);
1570 eh = ext_block_hdr(bh);
1571 ex = EXT_FIRST_EXTENT(eh);
1572found_extent:
1573 *logical = le32_to_cpu(ex->ee_block);
1574 *phys = ext4_ext_pblock(ex);
1575 *ret_ex = ex;
1576 if (bh)
1577 put_bh(bh);
1578 return 0;
1579}
1580
1581/*
1582 * ext4_ext_next_allocated_block:
1583 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1584 * NOTE: it considers block number from index entry as
1585 * allocated block. Thus, index entries have to be consistent
1586 * with leaves.
1587 */
1588ext4_lblk_t
1589ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1590{
1591 int depth;
1592
1593 BUG_ON(path == NULL);
1594 depth = path->p_depth;
1595
1596 if (depth == 0 && path->p_ext == NULL)
1597 return EXT_MAX_BLOCKS;
1598
1599 while (depth >= 0) {
1600 if (depth == path->p_depth) {
1601 /* leaf */
1602 if (path[depth].p_ext &&
1603 path[depth].p_ext !=
1604 EXT_LAST_EXTENT(path[depth].p_hdr))
1605 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1606 } else {
1607 /* index */
1608 if (path[depth].p_idx !=
1609 EXT_LAST_INDEX(path[depth].p_hdr))
1610 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1611 }
1612 depth--;
1613 }
1614
1615 return EXT_MAX_BLOCKS;
1616}
1617
1618/*
1619 * ext4_ext_next_leaf_block:
1620 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1621 */
1622static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1623{
1624 int depth;
1625
1626 BUG_ON(path == NULL);
1627 depth = path->p_depth;
1628
1629 /* zero-tree has no leaf blocks at all */
1630 if (depth == 0)
1631 return EXT_MAX_BLOCKS;
1632
1633 /* go to index block */
1634 depth--;
1635
1636 while (depth >= 0) {
1637 if (path[depth].p_idx !=
1638 EXT_LAST_INDEX(path[depth].p_hdr))
1639 return (ext4_lblk_t)
1640 le32_to_cpu(path[depth].p_idx[1].ei_block);
1641 depth--;
1642 }
1643
1644 return EXT_MAX_BLOCKS;
1645}
1646
1647/*
1648 * ext4_ext_correct_indexes:
1649 * if leaf gets modified and modified extent is first in the leaf,
1650 * then we have to correct all indexes above.
1651 * TODO: do we need to correct tree in all cases?
1652 */
1653static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1654 struct ext4_ext_path *path)
1655{
1656 struct ext4_extent_header *eh;
1657 int depth = ext_depth(inode);
1658 struct ext4_extent *ex;
1659 __le32 border;
1660 int k, err = 0;
1661
1662 eh = path[depth].p_hdr;
1663 ex = path[depth].p_ext;
1664
1665 if (unlikely(ex == NULL || eh == NULL)) {
1666 EXT4_ERROR_INODE(inode,
1667 "ex %p == NULL or eh %p == NULL", ex, eh);
1668 return -EFSCORRUPTED;
1669 }
1670
1671 if (depth == 0) {
1672 /* there is no tree at all */
1673 return 0;
1674 }
1675
1676 if (ex != EXT_FIRST_EXTENT(eh)) {
1677 /* we correct tree if first leaf got modified only */
1678 return 0;
1679 }
1680
1681 /*
1682 * TODO: we need correction if border is smaller than current one
1683 */
1684 k = depth - 1;
1685 border = path[depth].p_ext->ee_block;
1686 err = ext4_ext_get_access(handle, inode, path + k);
1687 if (err)
1688 return err;
1689 path[k].p_idx->ei_block = border;
1690 err = ext4_ext_dirty(handle, inode, path + k);
1691 if (err)
1692 return err;
1693
1694 while (k--) {
1695 /* change all left-side indexes */
1696 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1697 break;
1698 err = ext4_ext_get_access(handle, inode, path + k);
1699 if (err)
1700 break;
1701 path[k].p_idx->ei_block = border;
1702 err = ext4_ext_dirty(handle, inode, path + k);
1703 if (err)
1704 break;
1705 }
1706
1707 return err;
1708}
1709
1710int
1711ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1712 struct ext4_extent *ex2)
1713{
1714 unsigned short ext1_ee_len, ext2_ee_len;
1715
1716 if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1717 return 0;
1718
1719 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1720 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1721
1722 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1723 le32_to_cpu(ex2->ee_block))
1724 return 0;
1725
1726 /*
1727 * To allow future support for preallocated extents to be added
1728 * as an RO_COMPAT feature, refuse to merge to extents if
1729 * this can result in the top bit of ee_len being set.
1730 */
1731 if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1732 return 0;
1733 /*
1734 * The check for IO to unwritten extent is somewhat racy as we
1735 * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1736 * dropping i_data_sem. But reserved blocks should save us in that
1737 * case.
1738 */
1739 if (ext4_ext_is_unwritten(ex1) &&
1740 (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1741 atomic_read(&EXT4_I(inode)->i_unwritten) ||
1742 (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1743 return 0;
1744#ifdef AGGRESSIVE_TEST
1745 if (ext1_ee_len >= 4)
1746 return 0;
1747#endif
1748
1749 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1750 return 1;
1751 return 0;
1752}
1753
1754/*
1755 * This function tries to merge the "ex" extent to the next extent in the tree.
1756 * It always tries to merge towards right. If you want to merge towards
1757 * left, pass "ex - 1" as argument instead of "ex".
1758 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1759 * 1 if they got merged.
1760 */
1761static int ext4_ext_try_to_merge_right(struct inode *inode,
1762 struct ext4_ext_path *path,
1763 struct ext4_extent *ex)
1764{
1765 struct ext4_extent_header *eh;
1766 unsigned int depth, len;
1767 int merge_done = 0, unwritten;
1768
1769 depth = ext_depth(inode);
1770 BUG_ON(path[depth].p_hdr == NULL);
1771 eh = path[depth].p_hdr;
1772
1773 while (ex < EXT_LAST_EXTENT(eh)) {
1774 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1775 break;
1776 /* merge with next extent! */
1777 unwritten = ext4_ext_is_unwritten(ex);
1778 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1779 + ext4_ext_get_actual_len(ex + 1));
1780 if (unwritten)
1781 ext4_ext_mark_unwritten(ex);
1782
1783 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1784 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1785 * sizeof(struct ext4_extent);
1786 memmove(ex + 1, ex + 2, len);
1787 }
1788 le16_add_cpu(&eh->eh_entries, -1);
1789 merge_done = 1;
1790 WARN_ON(eh->eh_entries == 0);
1791 if (!eh->eh_entries)
1792 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1793 }
1794
1795 return merge_done;
1796}
1797
1798/*
1799 * This function does a very simple check to see if we can collapse
1800 * an extent tree with a single extent tree leaf block into the inode.
1801 */
1802static void ext4_ext_try_to_merge_up(handle_t *handle,
1803 struct inode *inode,
1804 struct ext4_ext_path *path)
1805{
1806 size_t s;
1807 unsigned max_root = ext4_ext_space_root(inode, 0);
1808 ext4_fsblk_t blk;
1809
1810 if ((path[0].p_depth != 1) ||
1811 (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1812 (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1813 return;
1814
1815 /*
1816 * We need to modify the block allocation bitmap and the block
1817 * group descriptor to release the extent tree block. If we
1818 * can't get the journal credits, give up.
1819 */
1820 if (ext4_journal_extend(handle, 2))
1821 return;
1822
1823 /*
1824 * Copy the extent data up to the inode
1825 */
1826 blk = ext4_idx_pblock(path[0].p_idx);
1827 s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1828 sizeof(struct ext4_extent_idx);
1829 s += sizeof(struct ext4_extent_header);
1830
1831 path[1].p_maxdepth = path[0].p_maxdepth;
1832 memcpy(path[0].p_hdr, path[1].p_hdr, s);
1833 path[0].p_depth = 0;
1834 path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1835 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1836 path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1837
1838 brelse(path[1].p_bh);
1839 ext4_free_blocks(handle, inode, NULL, blk, 1,
1840 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1841}
1842
1843/*
1844 * This function tries to merge the @ex extent to neighbours in the tree.
1845 * return 1 if merge left else 0.
1846 */
1847static void ext4_ext_try_to_merge(handle_t *handle,
1848 struct inode *inode,
1849 struct ext4_ext_path *path,
1850 struct ext4_extent *ex) {
1851 struct ext4_extent_header *eh;
1852 unsigned int depth;
1853 int merge_done = 0;
1854
1855 depth = ext_depth(inode);
1856 BUG_ON(path[depth].p_hdr == NULL);
1857 eh = path[depth].p_hdr;
1858
1859 if (ex > EXT_FIRST_EXTENT(eh))
1860 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1861
1862 if (!merge_done)
1863 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1864
1865 ext4_ext_try_to_merge_up(handle, inode, path);
1866}
1867
1868/*
1869 * check if a portion of the "newext" extent overlaps with an
1870 * existing extent.
1871 *
1872 * If there is an overlap discovered, it updates the length of the newext
1873 * such that there will be no overlap, and then returns 1.
1874 * If there is no overlap found, it returns 0.
1875 */
1876static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1877 struct inode *inode,
1878 struct ext4_extent *newext,
1879 struct ext4_ext_path *path)
1880{
1881 ext4_lblk_t b1, b2;
1882 unsigned int depth, len1;
1883 unsigned int ret = 0;
1884
1885 b1 = le32_to_cpu(newext->ee_block);
1886 len1 = ext4_ext_get_actual_len(newext);
1887 depth = ext_depth(inode);
1888 if (!path[depth].p_ext)
1889 goto out;
1890 b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1891
1892 /*
1893 * get the next allocated block if the extent in the path
1894 * is before the requested block(s)
1895 */
1896 if (b2 < b1) {
1897 b2 = ext4_ext_next_allocated_block(path);
1898 if (b2 == EXT_MAX_BLOCKS)
1899 goto out;
1900 b2 = EXT4_LBLK_CMASK(sbi, b2);
1901 }
1902
1903 /* check for wrap through zero on extent logical start block*/
1904 if (b1 + len1 < b1) {
1905 len1 = EXT_MAX_BLOCKS - b1;
1906 newext->ee_len = cpu_to_le16(len1);
1907 ret = 1;
1908 }
1909
1910 /* check for overlap */
1911 if (b1 + len1 > b2) {
1912 newext->ee_len = cpu_to_le16(b2 - b1);
1913 ret = 1;
1914 }
1915out:
1916 return ret;
1917}
1918
1919/*
1920 * ext4_ext_insert_extent:
1921 * tries to merge requsted extent into the existing extent or
1922 * inserts requested extent as new one into the tree,
1923 * creating new leaf in the no-space case.
1924 */
1925int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1926 struct ext4_ext_path **ppath,
1927 struct ext4_extent *newext, int gb_flags)
1928{
1929 struct ext4_ext_path *path = *ppath;
1930 struct ext4_extent_header *eh;
1931 struct ext4_extent *ex, *fex;
1932 struct ext4_extent *nearex; /* nearest extent */
1933 struct ext4_ext_path *npath = NULL;
1934 int depth, len, err;
1935 ext4_lblk_t next;
1936 int mb_flags = 0, unwritten;
1937
1938 if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1939 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1940 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1941 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1942 return -EFSCORRUPTED;
1943 }
1944 depth = ext_depth(inode);
1945 ex = path[depth].p_ext;
1946 eh = path[depth].p_hdr;
1947 if (unlikely(path[depth].p_hdr == NULL)) {
1948 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1949 return -EFSCORRUPTED;
1950 }
1951
1952 /* try to insert block into found extent and return */
1953 if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1954
1955 /*
1956 * Try to see whether we should rather test the extent on
1957 * right from ex, or from the left of ex. This is because
1958 * ext4_find_extent() can return either extent on the
1959 * left, or on the right from the searched position. This
1960 * will make merging more effective.
1961 */
1962 if (ex < EXT_LAST_EXTENT(eh) &&
1963 (le32_to_cpu(ex->ee_block) +
1964 ext4_ext_get_actual_len(ex) <
1965 le32_to_cpu(newext->ee_block))) {
1966 ex += 1;
1967 goto prepend;
1968 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1969 (le32_to_cpu(newext->ee_block) +
1970 ext4_ext_get_actual_len(newext) <
1971 le32_to_cpu(ex->ee_block)))
1972 ex -= 1;
1973
1974 /* Try to append newex to the ex */
1975 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1976 ext_debug("append [%d]%d block to %u:[%d]%d"
1977 "(from %llu)\n",
1978 ext4_ext_is_unwritten(newext),
1979 ext4_ext_get_actual_len(newext),
1980 le32_to_cpu(ex->ee_block),
1981 ext4_ext_is_unwritten(ex),
1982 ext4_ext_get_actual_len(ex),
1983 ext4_ext_pblock(ex));
1984 err = ext4_ext_get_access(handle, inode,
1985 path + depth);
1986 if (err)
1987 return err;
1988 unwritten = ext4_ext_is_unwritten(ex);
1989 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1990 + ext4_ext_get_actual_len(newext));
1991 if (unwritten)
1992 ext4_ext_mark_unwritten(ex);
1993 eh = path[depth].p_hdr;
1994 nearex = ex;
1995 goto merge;
1996 }
1997
1998prepend:
1999 /* Try to prepend newex to the ex */
2000 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2001 ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2002 "(from %llu)\n",
2003 le32_to_cpu(newext->ee_block),
2004 ext4_ext_is_unwritten(newext),
2005 ext4_ext_get_actual_len(newext),
2006 le32_to_cpu(ex->ee_block),
2007 ext4_ext_is_unwritten(ex),
2008 ext4_ext_get_actual_len(ex),
2009 ext4_ext_pblock(ex));
2010 err = ext4_ext_get_access(handle, inode,
2011 path + depth);
2012 if (err)
2013 return err;
2014
2015 unwritten = ext4_ext_is_unwritten(ex);
2016 ex->ee_block = newext->ee_block;
2017 ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2018 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2019 + ext4_ext_get_actual_len(newext));
2020 if (unwritten)
2021 ext4_ext_mark_unwritten(ex);
2022 eh = path[depth].p_hdr;
2023 nearex = ex;
2024 goto merge;
2025 }
2026 }
2027
2028 depth = ext_depth(inode);
2029 eh = path[depth].p_hdr;
2030 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2031 goto has_space;
2032
2033 /* probably next leaf has space for us? */
2034 fex = EXT_LAST_EXTENT(eh);
2035 next = EXT_MAX_BLOCKS;
2036 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2037 next = ext4_ext_next_leaf_block(path);
2038 if (next != EXT_MAX_BLOCKS) {
2039 ext_debug("next leaf block - %u\n", next);
2040 BUG_ON(npath != NULL);
2041 npath = ext4_find_extent(inode, next, NULL, 0);
2042 if (IS_ERR(npath))
2043 return PTR_ERR(npath);
2044 BUG_ON(npath->p_depth != path->p_depth);
2045 eh = npath[depth].p_hdr;
2046 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2047 ext_debug("next leaf isn't full(%d)\n",
2048 le16_to_cpu(eh->eh_entries));
2049 path = npath;
2050 goto has_space;
2051 }
2052 ext_debug("next leaf has no free space(%d,%d)\n",
2053 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2054 }
2055
2056 /*
2057 * There is no free space in the found leaf.
2058 * We're gonna add a new leaf in the tree.
2059 */
2060 if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2061 mb_flags |= EXT4_MB_USE_RESERVED;
2062 err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2063 ppath, newext);
2064 if (err)
2065 goto cleanup;
2066 depth = ext_depth(inode);
2067 eh = path[depth].p_hdr;
2068
2069has_space:
2070 nearex = path[depth].p_ext;
2071
2072 err = ext4_ext_get_access(handle, inode, path + depth);
2073 if (err)
2074 goto cleanup;
2075
2076 if (!nearex) {
2077 /* there is no extent in this leaf, create first one */
2078 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2079 le32_to_cpu(newext->ee_block),
2080 ext4_ext_pblock(newext),
2081 ext4_ext_is_unwritten(newext),
2082 ext4_ext_get_actual_len(newext));
2083 nearex = EXT_FIRST_EXTENT(eh);
2084 } else {
2085 if (le32_to_cpu(newext->ee_block)
2086 > le32_to_cpu(nearex->ee_block)) {
2087 /* Insert after */
2088 ext_debug("insert %u:%llu:[%d]%d before: "
2089 "nearest %p\n",
2090 le32_to_cpu(newext->ee_block),
2091 ext4_ext_pblock(newext),
2092 ext4_ext_is_unwritten(newext),
2093 ext4_ext_get_actual_len(newext),
2094 nearex);
2095 nearex++;
2096 } else {
2097 /* Insert before */
2098 BUG_ON(newext->ee_block == nearex->ee_block);
2099 ext_debug("insert %u:%llu:[%d]%d after: "
2100 "nearest %p\n",
2101 le32_to_cpu(newext->ee_block),
2102 ext4_ext_pblock(newext),
2103 ext4_ext_is_unwritten(newext),
2104 ext4_ext_get_actual_len(newext),
2105 nearex);
2106 }
2107 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2108 if (len > 0) {
2109 ext_debug("insert %u:%llu:[%d]%d: "
2110 "move %d extents from 0x%p to 0x%p\n",
2111 le32_to_cpu(newext->ee_block),
2112 ext4_ext_pblock(newext),
2113 ext4_ext_is_unwritten(newext),
2114 ext4_ext_get_actual_len(newext),
2115 len, nearex, nearex + 1);
2116 memmove(nearex + 1, nearex,
2117 len * sizeof(struct ext4_extent));
2118 }
2119 }
2120
2121 le16_add_cpu(&eh->eh_entries, 1);
2122 path[depth].p_ext = nearex;
2123 nearex->ee_block = newext->ee_block;
2124 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2125 nearex->ee_len = newext->ee_len;
2126
2127merge:
2128 /* try to merge extents */
2129 if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2130 ext4_ext_try_to_merge(handle, inode, path, nearex);
2131
2132
2133 /* time to correct all indexes above */
2134 err = ext4_ext_correct_indexes(handle, inode, path);
2135 if (err)
2136 goto cleanup;
2137
2138 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2139
2140cleanup:
2141 ext4_ext_drop_refs(npath);
2142 kfree(npath);
2143 return err;
2144}
2145
2146static int ext4_fill_fiemap_extents(struct inode *inode,
2147 ext4_lblk_t block, ext4_lblk_t num,
2148 struct fiemap_extent_info *fieinfo)
2149{
2150 struct ext4_ext_path *path = NULL;
2151 struct ext4_extent *ex;
2152 struct extent_status es;
2153 ext4_lblk_t next, next_del, start = 0, end = 0;
2154 ext4_lblk_t last = block + num;
2155 int exists, depth = 0, err = 0;
2156 unsigned int flags = 0;
2157 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2158
2159 while (block < last && block != EXT_MAX_BLOCKS) {
2160 num = last - block;
2161 /* find extent for this block */
2162 down_read(&EXT4_I(inode)->i_data_sem);
2163
2164 path = ext4_find_extent(inode, block, &path, 0);
2165 if (IS_ERR(path)) {
2166 up_read(&EXT4_I(inode)->i_data_sem);
2167 err = PTR_ERR(path);
2168 path = NULL;
2169 break;
2170 }
2171
2172 depth = ext_depth(inode);
2173 if (unlikely(path[depth].p_hdr == NULL)) {
2174 up_read(&EXT4_I(inode)->i_data_sem);
2175 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2176 err = -EFSCORRUPTED;
2177 break;
2178 }
2179 ex = path[depth].p_ext;
2180 next = ext4_ext_next_allocated_block(path);
2181
2182 flags = 0;
2183 exists = 0;
2184 if (!ex) {
2185 /* there is no extent yet, so try to allocate
2186 * all requested space */
2187 start = block;
2188 end = block + num;
2189 } else if (le32_to_cpu(ex->ee_block) > block) {
2190 /* need to allocate space before found extent */
2191 start = block;
2192 end = le32_to_cpu(ex->ee_block);
2193 if (block + num < end)
2194 end = block + num;
2195 } else if (block >= le32_to_cpu(ex->ee_block)
2196 + ext4_ext_get_actual_len(ex)) {
2197 /* need to allocate space after found extent */
2198 start = block;
2199 end = block + num;
2200 if (end >= next)
2201 end = next;
2202 } else if (block >= le32_to_cpu(ex->ee_block)) {
2203 /*
2204 * some part of requested space is covered
2205 * by found extent
2206 */
2207 start = block;
2208 end = le32_to_cpu(ex->ee_block)
2209 + ext4_ext_get_actual_len(ex);
2210 if (block + num < end)
2211 end = block + num;
2212 exists = 1;
2213 } else {
2214 BUG();
2215 }
2216 BUG_ON(end <= start);
2217
2218 if (!exists) {
2219 es.es_lblk = start;
2220 es.es_len = end - start;
2221 es.es_pblk = 0;
2222 } else {
2223 es.es_lblk = le32_to_cpu(ex->ee_block);
2224 es.es_len = ext4_ext_get_actual_len(ex);
2225 es.es_pblk = ext4_ext_pblock(ex);
2226 if (ext4_ext_is_unwritten(ex))
2227 flags |= FIEMAP_EXTENT_UNWRITTEN;
2228 }
2229
2230 /*
2231 * Find delayed extent and update es accordingly. We call
2232 * it even in !exists case to find out whether es is the
2233 * last existing extent or not.
2234 */
2235 next_del = ext4_find_delayed_extent(inode, &es);
2236 if (!exists && next_del) {
2237 exists = 1;
2238 flags |= (FIEMAP_EXTENT_DELALLOC |
2239 FIEMAP_EXTENT_UNKNOWN);
2240 }
2241 up_read(&EXT4_I(inode)->i_data_sem);
2242
2243 if (unlikely(es.es_len == 0)) {
2244 EXT4_ERROR_INODE(inode, "es.es_len == 0");
2245 err = -EFSCORRUPTED;
2246 break;
2247 }
2248
2249 /*
2250 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2251 * we need to check next == EXT_MAX_BLOCKS because it is
2252 * possible that an extent is with unwritten and delayed
2253 * status due to when an extent is delayed allocated and
2254 * is allocated by fallocate status tree will track both of
2255 * them in a extent.
2256 *
2257 * So we could return a unwritten and delayed extent, and
2258 * its block is equal to 'next'.
2259 */
2260 if (next == next_del && next == EXT_MAX_BLOCKS) {
2261 flags |= FIEMAP_EXTENT_LAST;
2262 if (unlikely(next_del != EXT_MAX_BLOCKS ||
2263 next != EXT_MAX_BLOCKS)) {
2264 EXT4_ERROR_INODE(inode,
2265 "next extent == %u, next "
2266 "delalloc extent = %u",
2267 next, next_del);
2268 err = -EFSCORRUPTED;
2269 break;
2270 }
2271 }
2272
2273 if (exists) {
2274 err = fiemap_fill_next_extent(fieinfo,
2275 (__u64)es.es_lblk << blksize_bits,
2276 (__u64)es.es_pblk << blksize_bits,
2277 (__u64)es.es_len << blksize_bits,
2278 flags);
2279 if (err < 0)
2280 break;
2281 if (err == 1) {
2282 err = 0;
2283 break;
2284 }
2285 }
2286
2287 block = es.es_lblk + es.es_len;
2288 }
2289
2290 ext4_ext_drop_refs(path);
2291 kfree(path);
2292 return err;
2293}
2294
2295/*
2296 * ext4_ext_determine_hole - determine hole around given block
2297 * @inode: inode we lookup in
2298 * @path: path in extent tree to @lblk
2299 * @lblk: pointer to logical block around which we want to determine hole
2300 *
2301 * Determine hole length (and start if easily possible) around given logical
2302 * block. We don't try too hard to find the beginning of the hole but @path
2303 * actually points to extent before @lblk, we provide it.
2304 *
2305 * The function returns the length of a hole starting at @lblk. We update @lblk
2306 * to the beginning of the hole if we managed to find it.
2307 */
2308static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2309 struct ext4_ext_path *path,
2310 ext4_lblk_t *lblk)
2311{
2312 int depth = ext_depth(inode);
2313 struct ext4_extent *ex;
2314 ext4_lblk_t len;
2315
2316 ex = path[depth].p_ext;
2317 if (ex == NULL) {
2318 /* there is no extent yet, so gap is [0;-] */
2319 *lblk = 0;
2320 len = EXT_MAX_BLOCKS;
2321 } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2322 len = le32_to_cpu(ex->ee_block) - *lblk;
2323 } else if (*lblk >= le32_to_cpu(ex->ee_block)
2324 + ext4_ext_get_actual_len(ex)) {
2325 ext4_lblk_t next;
2326
2327 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2328 next = ext4_ext_next_allocated_block(path);
2329 BUG_ON(next == *lblk);
2330 len = next - *lblk;
2331 } else {
2332 BUG();
2333 }
2334 return len;
2335}
2336
2337/*
2338 * ext4_ext_put_gap_in_cache:
2339 * calculate boundaries of the gap that the requested block fits into
2340 * and cache this gap
2341 */
2342static void
2343ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2344 ext4_lblk_t hole_len)
2345{
2346 struct extent_status es;
2347
2348 ext4_es_find_delayed_extent_range(inode, hole_start,
2349 hole_start + hole_len - 1, &es);
2350 if (es.es_len) {
2351 /* There's delayed extent containing lblock? */
2352 if (es.es_lblk <= hole_start)
2353 return;
2354 hole_len = min(es.es_lblk - hole_start, hole_len);
2355 }
2356 ext_debug(" -> %u:%u\n", hole_start, hole_len);
2357 ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2358 EXTENT_STATUS_HOLE);
2359}
2360
2361/*
2362 * ext4_ext_rm_idx:
2363 * removes index from the index block.
2364 */
2365static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2366 struct ext4_ext_path *path, int depth)
2367{
2368 int err;
2369 ext4_fsblk_t leaf;
2370
2371 /* free index block */
2372 depth--;
2373 path = path + depth;
2374 leaf = ext4_idx_pblock(path->p_idx);
2375 if (unlikely(path->p_hdr->eh_entries == 0)) {
2376 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2377 return -EFSCORRUPTED;
2378 }
2379 err = ext4_ext_get_access(handle, inode, path);
2380 if (err)
2381 return err;
2382
2383 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2384 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2385 len *= sizeof(struct ext4_extent_idx);
2386 memmove(path->p_idx, path->p_idx + 1, len);
2387 }
2388
2389 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2390 err = ext4_ext_dirty(handle, inode, path);
2391 if (err)
2392 return err;
2393 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2394 trace_ext4_ext_rm_idx(inode, leaf);
2395
2396 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2397 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2398
2399 while (--depth >= 0) {
2400 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2401 break;
2402 path--;
2403 err = ext4_ext_get_access(handle, inode, path);
2404 if (err)
2405 break;
2406 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2407 err = ext4_ext_dirty(handle, inode, path);
2408 if (err)
2409 break;
2410 }
2411 return err;
2412}
2413
2414/*
2415 * ext4_ext_calc_credits_for_single_extent:
2416 * This routine returns max. credits that needed to insert an extent
2417 * to the extent tree.
2418 * When pass the actual path, the caller should calculate credits
2419 * under i_data_sem.
2420 */
2421int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2422 struct ext4_ext_path *path)
2423{
2424 if (path) {
2425 int depth = ext_depth(inode);
2426 int ret = 0;
2427
2428 /* probably there is space in leaf? */
2429 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2430 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2431
2432 /*
2433 * There are some space in the leaf tree, no
2434 * need to account for leaf block credit
2435 *
2436 * bitmaps and block group descriptor blocks
2437 * and other metadata blocks still need to be
2438 * accounted.
2439 */
2440 /* 1 bitmap, 1 block group descriptor */
2441 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2442 return ret;
2443 }
2444 }
2445
2446 return ext4_chunk_trans_blocks(inode, nrblocks);
2447}
2448
2449/*
2450 * How many index/leaf blocks need to change/allocate to add @extents extents?
2451 *
2452 * If we add a single extent, then in the worse case, each tree level
2453 * index/leaf need to be changed in case of the tree split.
2454 *
2455 * If more extents are inserted, they could cause the whole tree split more
2456 * than once, but this is really rare.
2457 */
2458int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2459{
2460 int index;
2461 int depth;
2462
2463 /* If we are converting the inline data, only one is needed here. */
2464 if (ext4_has_inline_data(inode))
2465 return 1;
2466
2467 depth = ext_depth(inode);
2468
2469 if (extents <= 1)
2470 index = depth * 2;
2471 else
2472 index = depth * 3;
2473
2474 return index;
2475}
2476
2477static inline int get_default_free_blocks_flags(struct inode *inode)
2478{
2479 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2480 ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2481 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2482 else if (ext4_should_journal_data(inode))
2483 return EXT4_FREE_BLOCKS_FORGET;
2484 return 0;
2485}
2486
2487static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2488 struct ext4_extent *ex,
2489 long long *partial_cluster,
2490 ext4_lblk_t from, ext4_lblk_t to)
2491{
2492 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2493 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2494 ext4_fsblk_t pblk;
2495 int flags = get_default_free_blocks_flags(inode);
2496
2497 /*
2498 * For bigalloc file systems, we never free a partial cluster
2499 * at the beginning of the extent. Instead, we make a note
2500 * that we tried freeing the cluster, and check to see if we
2501 * need to free it on a subsequent call to ext4_remove_blocks,
2502 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2503 */
2504 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2505
2506 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2507 /*
2508 * If we have a partial cluster, and it's different from the
2509 * cluster of the last block, we need to explicitly free the
2510 * partial cluster here.
2511 */
2512 pblk = ext4_ext_pblock(ex) + ee_len - 1;
2513 if (*partial_cluster > 0 &&
2514 *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2515 ext4_free_blocks(handle, inode, NULL,
2516 EXT4_C2B(sbi, *partial_cluster),
2517 sbi->s_cluster_ratio, flags);
2518 *partial_cluster = 0;
2519 }
2520
2521#ifdef EXTENTS_STATS
2522 {
2523 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2524 spin_lock(&sbi->s_ext_stats_lock);
2525 sbi->s_ext_blocks += ee_len;
2526 sbi->s_ext_extents++;
2527 if (ee_len < sbi->s_ext_min)
2528 sbi->s_ext_min = ee_len;
2529 if (ee_len > sbi->s_ext_max)
2530 sbi->s_ext_max = ee_len;
2531 if (ext_depth(inode) > sbi->s_depth_max)
2532 sbi->s_depth_max = ext_depth(inode);
2533 spin_unlock(&sbi->s_ext_stats_lock);
2534 }
2535#endif
2536 if (from >= le32_to_cpu(ex->ee_block)
2537 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2538 /* tail removal */
2539 ext4_lblk_t num;
2540 long long first_cluster;
2541
2542 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2543 pblk = ext4_ext_pblock(ex) + ee_len - num;
2544 /*
2545 * Usually we want to free partial cluster at the end of the
2546 * extent, except for the situation when the cluster is still
2547 * used by any other extent (partial_cluster is negative).
2548 */
2549 if (*partial_cluster < 0 &&
2550 *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2551 flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2552
2553 ext_debug("free last %u blocks starting %llu partial %lld\n",
2554 num, pblk, *partial_cluster);
2555 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2556 /*
2557 * If the block range to be freed didn't start at the
2558 * beginning of a cluster, and we removed the entire
2559 * extent and the cluster is not used by any other extent,
2560 * save the partial cluster here, since we might need to
2561 * delete if we determine that the truncate or punch hole
2562 * operation has removed all of the blocks in the cluster.
2563 * If that cluster is used by another extent, preserve its
2564 * negative value so it isn't freed later on.
2565 *
2566 * If the whole extent wasn't freed, we've reached the
2567 * start of the truncated/punched region and have finished
2568 * removing blocks. If there's a partial cluster here it's
2569 * shared with the remainder of the extent and is no longer
2570 * a candidate for removal.
2571 */
2572 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2573 first_cluster = (long long) EXT4_B2C(sbi, pblk);
2574 if (first_cluster != -*partial_cluster)
2575 *partial_cluster = first_cluster;
2576 } else {
2577 *partial_cluster = 0;
2578 }
2579 } else
2580 ext4_error(sbi->s_sb, "strange request: removal(2) "
2581 "%u-%u from %u:%u",
2582 from, to, le32_to_cpu(ex->ee_block), ee_len);
2583 return 0;
2584}
2585
2586
2587/*
2588 * ext4_ext_rm_leaf() Removes the extents associated with the
2589 * blocks appearing between "start" and "end". Both "start"
2590 * and "end" must appear in the same extent or EIO is returned.
2591 *
2592 * @handle: The journal handle
2593 * @inode: The files inode
2594 * @path: The path to the leaf
2595 * @partial_cluster: The cluster which we'll have to free if all extents
2596 * has been released from it. However, if this value is
2597 * negative, it's a cluster just to the right of the
2598 * punched region and it must not be freed.
2599 * @start: The first block to remove
2600 * @end: The last block to remove
2601 */
2602static int
2603ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2604 struct ext4_ext_path *path,
2605 long long *partial_cluster,
2606 ext4_lblk_t start, ext4_lblk_t end)
2607{
2608 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2609 int err = 0, correct_index = 0;
2610 int depth = ext_depth(inode), credits;
2611 struct ext4_extent_header *eh;
2612 ext4_lblk_t a, b;
2613 unsigned num;
2614 ext4_lblk_t ex_ee_block;
2615 unsigned short ex_ee_len;
2616 unsigned unwritten = 0;
2617 struct ext4_extent *ex;
2618 ext4_fsblk_t pblk;
2619
2620 /* the header must be checked already in ext4_ext_remove_space() */
2621 ext_debug("truncate since %u in leaf to %u\n", start, end);
2622 if (!path[depth].p_hdr)
2623 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2624 eh = path[depth].p_hdr;
2625 if (unlikely(path[depth].p_hdr == NULL)) {
2626 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2627 return -EFSCORRUPTED;
2628 }
2629 /* find where to start removing */
2630 ex = path[depth].p_ext;
2631 if (!ex)
2632 ex = EXT_LAST_EXTENT(eh);
2633
2634 ex_ee_block = le32_to_cpu(ex->ee_block);
2635 ex_ee_len = ext4_ext_get_actual_len(ex);
2636
2637 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2638
2639 while (ex >= EXT_FIRST_EXTENT(eh) &&
2640 ex_ee_block + ex_ee_len > start) {
2641
2642 if (ext4_ext_is_unwritten(ex))
2643 unwritten = 1;
2644 else
2645 unwritten = 0;
2646
2647 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2648 unwritten, ex_ee_len);
2649 path[depth].p_ext = ex;
2650
2651 a = ex_ee_block > start ? ex_ee_block : start;
2652 b = ex_ee_block+ex_ee_len - 1 < end ?
2653 ex_ee_block+ex_ee_len - 1 : end;
2654
2655 ext_debug(" border %u:%u\n", a, b);
2656
2657 /* If this extent is beyond the end of the hole, skip it */
2658 if (end < ex_ee_block) {
2659 /*
2660 * We're going to skip this extent and move to another,
2661 * so note that its first cluster is in use to avoid
2662 * freeing it when removing blocks. Eventually, the
2663 * right edge of the truncated/punched region will
2664 * be just to the left.
2665 */
2666 if (sbi->s_cluster_ratio > 1) {
2667 pblk = ext4_ext_pblock(ex);
2668 *partial_cluster =
2669 -(long long) EXT4_B2C(sbi, pblk);
2670 }
2671 ex--;
2672 ex_ee_block = le32_to_cpu(ex->ee_block);
2673 ex_ee_len = ext4_ext_get_actual_len(ex);
2674 continue;
2675 } else if (b != ex_ee_block + ex_ee_len - 1) {
2676 EXT4_ERROR_INODE(inode,
2677 "can not handle truncate %u:%u "
2678 "on extent %u:%u",
2679 start, end, ex_ee_block,
2680 ex_ee_block + ex_ee_len - 1);
2681 err = -EFSCORRUPTED;
2682 goto out;
2683 } else if (a != ex_ee_block) {
2684 /* remove tail of the extent */
2685 num = a - ex_ee_block;
2686 } else {
2687 /* remove whole extent: excellent! */
2688 num = 0;
2689 }
2690 /*
2691 * 3 for leaf, sb, and inode plus 2 (bmap and group
2692 * descriptor) for each block group; assume two block
2693 * groups plus ex_ee_len/blocks_per_block_group for
2694 * the worst case
2695 */
2696 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2697 if (ex == EXT_FIRST_EXTENT(eh)) {
2698 correct_index = 1;
2699 credits += (ext_depth(inode)) + 1;
2700 }
2701 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2702
2703 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2704 if (err)
2705 goto out;
2706
2707 err = ext4_ext_get_access(handle, inode, path + depth);
2708 if (err)
2709 goto out;
2710
2711 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2712 a, b);
2713 if (err)
2714 goto out;
2715
2716 if (num == 0)
2717 /* this extent is removed; mark slot entirely unused */
2718 ext4_ext_store_pblock(ex, 0);
2719
2720 ex->ee_len = cpu_to_le16(num);
2721 /*
2722 * Do not mark unwritten if all the blocks in the
2723 * extent have been removed.
2724 */
2725 if (unwritten && num)
2726 ext4_ext_mark_unwritten(ex);
2727 /*
2728 * If the extent was completely released,
2729 * we need to remove it from the leaf
2730 */
2731 if (num == 0) {
2732 if (end != EXT_MAX_BLOCKS - 1) {
2733 /*
2734 * For hole punching, we need to scoot all the
2735 * extents up when an extent is removed so that
2736 * we dont have blank extents in the middle
2737 */
2738 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2739 sizeof(struct ext4_extent));
2740
2741 /* Now get rid of the one at the end */
2742 memset(EXT_LAST_EXTENT(eh), 0,
2743 sizeof(struct ext4_extent));
2744 }
2745 le16_add_cpu(&eh->eh_entries, -1);
2746 }
2747
2748 err = ext4_ext_dirty(handle, inode, path + depth);
2749 if (err)
2750 goto out;
2751
2752 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2753 ext4_ext_pblock(ex));
2754 ex--;
2755 ex_ee_block = le32_to_cpu(ex->ee_block);
2756 ex_ee_len = ext4_ext_get_actual_len(ex);
2757 }
2758
2759 if (correct_index && eh->eh_entries)
2760 err = ext4_ext_correct_indexes(handle, inode, path);
2761
2762 /*
2763 * If there's a partial cluster and at least one extent remains in
2764 * the leaf, free the partial cluster if it isn't shared with the
2765 * current extent. If it is shared with the current extent
2766 * we zero partial_cluster because we've reached the start of the
2767 * truncated/punched region and we're done removing blocks.
2768 */
2769 if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2770 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2771 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2772 ext4_free_blocks(handle, inode, NULL,
2773 EXT4_C2B(sbi, *partial_cluster),
2774 sbi->s_cluster_ratio,
2775 get_default_free_blocks_flags(inode));
2776 }
2777 *partial_cluster = 0;
2778 }
2779
2780 /* if this leaf is free, then we should
2781 * remove it from index block above */
2782 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2783 err = ext4_ext_rm_idx(handle, inode, path, depth);
2784
2785out:
2786 return err;
2787}
2788
2789/*
2790 * ext4_ext_more_to_rm:
2791 * returns 1 if current index has to be freed (even partial)
2792 */
2793static int
2794ext4_ext_more_to_rm(struct ext4_ext_path *path)
2795{
2796 BUG_ON(path->p_idx == NULL);
2797
2798 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2799 return 0;
2800
2801 /*
2802 * if truncate on deeper level happened, it wasn't partial,
2803 * so we have to consider current index for truncation
2804 */
2805 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2806 return 0;
2807 return 1;
2808}
2809
2810int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2811 ext4_lblk_t end)
2812{
2813 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2814 int depth = ext_depth(inode);
2815 struct ext4_ext_path *path = NULL;
2816 long long partial_cluster = 0;
2817 handle_t *handle;
2818 int i = 0, err = 0;
2819
2820 ext_debug("truncate since %u to %u\n", start, end);
2821
2822 /* probably first extent we're gonna free will be last in block */
2823 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2824 if (IS_ERR(handle))
2825 return PTR_ERR(handle);
2826
2827again:
2828 trace_ext4_ext_remove_space(inode, start, end, depth);
2829
2830 /*
2831 * Check if we are removing extents inside the extent tree. If that
2832 * is the case, we are going to punch a hole inside the extent tree
2833 * so we have to check whether we need to split the extent covering
2834 * the last block to remove so we can easily remove the part of it
2835 * in ext4_ext_rm_leaf().
2836 */
2837 if (end < EXT_MAX_BLOCKS - 1) {
2838 struct ext4_extent *ex;
2839 ext4_lblk_t ee_block, ex_end, lblk;
2840 ext4_fsblk_t pblk;
2841
2842 /* find extent for or closest extent to this block */
2843 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2844 if (IS_ERR(path)) {
2845 ext4_journal_stop(handle);
2846 return PTR_ERR(path);
2847 }
2848 depth = ext_depth(inode);
2849 /* Leaf not may not exist only if inode has no blocks at all */
2850 ex = path[depth].p_ext;
2851 if (!ex) {
2852 if (depth) {
2853 EXT4_ERROR_INODE(inode,
2854 "path[%d].p_hdr == NULL",
2855 depth);
2856 err = -EFSCORRUPTED;
2857 }
2858 goto out;
2859 }
2860
2861 ee_block = le32_to_cpu(ex->ee_block);
2862 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2863
2864 /*
2865 * See if the last block is inside the extent, if so split
2866 * the extent at 'end' block so we can easily remove the
2867 * tail of the first part of the split extent in
2868 * ext4_ext_rm_leaf().
2869 */
2870 if (end >= ee_block && end < ex_end) {
2871
2872 /*
2873 * If we're going to split the extent, note that
2874 * the cluster containing the block after 'end' is
2875 * in use to avoid freeing it when removing blocks.
2876 */
2877 if (sbi->s_cluster_ratio > 1) {
2878 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2879 partial_cluster =
2880 -(long long) EXT4_B2C(sbi, pblk);
2881 }
2882
2883 /*
2884 * Split the extent in two so that 'end' is the last
2885 * block in the first new extent. Also we should not
2886 * fail removing space due to ENOSPC so try to use
2887 * reserved block if that happens.
2888 */
2889 err = ext4_force_split_extent_at(handle, inode, &path,
2890 end + 1, 1);
2891 if (err < 0)
2892 goto out;
2893
2894 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2895 /*
2896 * If there's an extent to the right its first cluster
2897 * contains the immediate right boundary of the
2898 * truncated/punched region. Set partial_cluster to
2899 * its negative value so it won't be freed if shared
2900 * with the current extent. The end < ee_block case
2901 * is handled in ext4_ext_rm_leaf().
2902 */
2903 lblk = ex_end + 1;
2904 err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2905 &ex);
2906 if (err)
2907 goto out;
2908 if (pblk)
2909 partial_cluster =
2910 -(long long) EXT4_B2C(sbi, pblk);
2911 }
2912 }
2913 /*
2914 * We start scanning from right side, freeing all the blocks
2915 * after i_size and walking into the tree depth-wise.
2916 */
2917 depth = ext_depth(inode);
2918 if (path) {
2919 int k = i = depth;
2920 while (--k > 0)
2921 path[k].p_block =
2922 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2923 } else {
2924 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2925 GFP_NOFS);
2926 if (path == NULL) {
2927 ext4_journal_stop(handle);
2928 return -ENOMEM;
2929 }
2930 path[0].p_maxdepth = path[0].p_depth = depth;
2931 path[0].p_hdr = ext_inode_hdr(inode);
2932 i = 0;
2933
2934 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2935 err = -EFSCORRUPTED;
2936 goto out;
2937 }
2938 }
2939 err = 0;
2940
2941 while (i >= 0 && err == 0) {
2942 if (i == depth) {
2943 /* this is leaf block */
2944 err = ext4_ext_rm_leaf(handle, inode, path,
2945 &partial_cluster, start,
2946 end);
2947 /* root level has p_bh == NULL, brelse() eats this */
2948 brelse(path[i].p_bh);
2949 path[i].p_bh = NULL;
2950 i--;
2951 continue;
2952 }
2953
2954 /* this is index block */
2955 if (!path[i].p_hdr) {
2956 ext_debug("initialize header\n");
2957 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2958 }
2959
2960 if (!path[i].p_idx) {
2961 /* this level hasn't been touched yet */
2962 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2963 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2964 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2965 path[i].p_hdr,
2966 le16_to_cpu(path[i].p_hdr->eh_entries));
2967 } else {
2968 /* we were already here, see at next index */
2969 path[i].p_idx--;
2970 }
2971
2972 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2973 i, EXT_FIRST_INDEX(path[i].p_hdr),
2974 path[i].p_idx);
2975 if (ext4_ext_more_to_rm(path + i)) {
2976 struct buffer_head *bh;
2977 /* go to the next level */
2978 ext_debug("move to level %d (block %llu)\n",
2979 i + 1, ext4_idx_pblock(path[i].p_idx));
2980 memset(path + i + 1, 0, sizeof(*path));
2981 bh = read_extent_tree_block(inode,
2982 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2983 EXT4_EX_NOCACHE);
2984 if (IS_ERR(bh)) {
2985 /* should we reset i_size? */
2986 err = PTR_ERR(bh);
2987 break;
2988 }
2989 /* Yield here to deal with large extent trees.
2990 * Should be a no-op if we did IO above. */
2991 cond_resched();
2992 if (WARN_ON(i + 1 > depth)) {
2993 err = -EFSCORRUPTED;
2994 break;
2995 }
2996 path[i + 1].p_bh = bh;
2997
2998 /* save actual number of indexes since this
2999 * number is changed at the next iteration */
3000 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3001 i++;
3002 } else {
3003 /* we finished processing this index, go up */
3004 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3005 /* index is empty, remove it;
3006 * handle must be already prepared by the
3007 * truncatei_leaf() */
3008 err = ext4_ext_rm_idx(handle, inode, path, i);
3009 }
3010 /* root level has p_bh == NULL, brelse() eats this */
3011 brelse(path[i].p_bh);
3012 path[i].p_bh = NULL;
3013 i--;
3014 ext_debug("return to level %d\n", i);
3015 }
3016 }
3017
3018 trace_ext4_ext_remove_space_done(inode, start, end, depth,
3019 partial_cluster, path->p_hdr->eh_entries);
3020
3021 /*
3022 * If we still have something in the partial cluster and we have removed
3023 * even the first extent, then we should free the blocks in the partial
3024 * cluster as well. (This code will only run when there are no leaves
3025 * to the immediate left of the truncated/punched region.)
3026 */
3027 if (partial_cluster > 0 && err == 0) {
3028 /* don't zero partial_cluster since it's not used afterwards */
3029 ext4_free_blocks(handle, inode, NULL,
3030 EXT4_C2B(sbi, partial_cluster),
3031 sbi->s_cluster_ratio,
3032 get_default_free_blocks_flags(inode));
3033 }
3034
3035 /* TODO: flexible tree reduction should be here */
3036 if (path->p_hdr->eh_entries == 0) {
3037 /*
3038 * truncate to zero freed all the tree,
3039 * so we need to correct eh_depth
3040 */
3041 err = ext4_ext_get_access(handle, inode, path);
3042 if (err == 0) {
3043 ext_inode_hdr(inode)->eh_depth = 0;
3044 ext_inode_hdr(inode)->eh_max =
3045 cpu_to_le16(ext4_ext_space_root(inode, 0));
3046 err = ext4_ext_dirty(handle, inode, path);
3047 }
3048 }
3049out:
3050 ext4_ext_drop_refs(path);
3051 kfree(path);
3052 path = NULL;
3053 if (err == -EAGAIN)
3054 goto again;
3055 ext4_journal_stop(handle);
3056
3057 return err;
3058}
3059
3060/*
3061 * called at mount time
3062 */
3063void ext4_ext_init(struct super_block *sb)
3064{
3065 /*
3066 * possible initialization would be here
3067 */
3068
3069 if (ext4_has_feature_extents(sb)) {
3070#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3071 printk(KERN_INFO "EXT4-fs: file extents enabled"
3072#ifdef AGGRESSIVE_TEST
3073 ", aggressive tests"
3074#endif
3075#ifdef CHECK_BINSEARCH
3076 ", check binsearch"
3077#endif
3078#ifdef EXTENTS_STATS
3079 ", stats"
3080#endif
3081 "\n");
3082#endif
3083#ifdef EXTENTS_STATS
3084 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3085 EXT4_SB(sb)->s_ext_min = 1 << 30;
3086 EXT4_SB(sb)->s_ext_max = 0;
3087#endif
3088 }
3089}
3090
3091/*
3092 * called at umount time
3093 */
3094void ext4_ext_release(struct super_block *sb)
3095{
3096 if (!ext4_has_feature_extents(sb))
3097 return;
3098
3099#ifdef EXTENTS_STATS
3100 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3101 struct ext4_sb_info *sbi = EXT4_SB(sb);
3102 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3103 sbi->s_ext_blocks, sbi->s_ext_extents,
3104 sbi->s_ext_blocks / sbi->s_ext_extents);
3105 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3106 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3107 }
3108#endif
3109}
3110
3111static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3112{
3113 ext4_lblk_t ee_block;
3114 ext4_fsblk_t ee_pblock;
3115 unsigned int ee_len;
3116
3117 ee_block = le32_to_cpu(ex->ee_block);
3118 ee_len = ext4_ext_get_actual_len(ex);
3119 ee_pblock = ext4_ext_pblock(ex);
3120
3121 if (ee_len == 0)
3122 return 0;
3123
3124 return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3125 EXTENT_STATUS_WRITTEN);
3126}
3127
3128/* FIXME!! we need to try to merge to left or right after zero-out */
3129static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3130{
3131 ext4_fsblk_t ee_pblock;
3132 unsigned int ee_len;
3133
3134 ee_len = ext4_ext_get_actual_len(ex);
3135 ee_pblock = ext4_ext_pblock(ex);
3136 return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3137 ee_len);
3138}
3139
3140/*
3141 * ext4_split_extent_at() splits an extent at given block.
3142 *
3143 * @handle: the journal handle
3144 * @inode: the file inode
3145 * @path: the path to the extent
3146 * @split: the logical block where the extent is splitted.
3147 * @split_flags: indicates if the extent could be zeroout if split fails, and
3148 * the states(init or unwritten) of new extents.
3149 * @flags: flags used to insert new extent to extent tree.
3150 *
3151 *
3152 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3153 * of which are deterimined by split_flag.
3154 *
3155 * There are two cases:
3156 * a> the extent are splitted into two extent.
3157 * b> split is not needed, and just mark the extent.
3158 *
3159 * return 0 on success.
3160 */
3161static int ext4_split_extent_at(handle_t *handle,
3162 struct inode *inode,
3163 struct ext4_ext_path **ppath,
3164 ext4_lblk_t split,
3165 int split_flag,
3166 int flags)
3167{
3168 struct ext4_ext_path *path = *ppath;
3169 ext4_fsblk_t newblock;
3170 ext4_lblk_t ee_block;
3171 struct ext4_extent *ex, newex, orig_ex, zero_ex;
3172 struct ext4_extent *ex2 = NULL;
3173 unsigned int ee_len, depth;
3174 int err = 0;
3175
3176 BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3177 (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3178
3179 ext_debug("ext4_split_extents_at: inode %lu, logical"
3180 "block %llu\n", inode->i_ino, (unsigned long long)split);
3181
3182 ext4_ext_show_leaf(inode, path);
3183
3184 depth = ext_depth(inode);
3185 ex = path[depth].p_ext;
3186 ee_block = le32_to_cpu(ex->ee_block);
3187 ee_len = ext4_ext_get_actual_len(ex);
3188 newblock = split - ee_block + ext4_ext_pblock(ex);
3189
3190 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3191 BUG_ON(!ext4_ext_is_unwritten(ex) &&
3192 split_flag & (EXT4_EXT_MAY_ZEROOUT |
3193 EXT4_EXT_MARK_UNWRIT1 |
3194 EXT4_EXT_MARK_UNWRIT2));
3195
3196 err = ext4_ext_get_access(handle, inode, path + depth);
3197 if (err)
3198 goto out;
3199
3200 if (split == ee_block) {
3201 /*
3202 * case b: block @split is the block that the extent begins with
3203 * then we just change the state of the extent, and splitting
3204 * is not needed.
3205 */
3206 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3207 ext4_ext_mark_unwritten(ex);
3208 else
3209 ext4_ext_mark_initialized(ex);
3210
3211 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3212 ext4_ext_try_to_merge(handle, inode, path, ex);
3213
3214 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3215 goto out;
3216 }
3217
3218 /* case a */
3219 memcpy(&orig_ex, ex, sizeof(orig_ex));
3220 ex->ee_len = cpu_to_le16(split - ee_block);
3221 if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3222 ext4_ext_mark_unwritten(ex);
3223
3224 /*
3225 * path may lead to new leaf, not to original leaf any more
3226 * after ext4_ext_insert_extent() returns,
3227 */
3228 err = ext4_ext_dirty(handle, inode, path + depth);
3229 if (err)
3230 goto fix_extent_len;
3231
3232 ex2 = &newex;
3233 ex2->ee_block = cpu_to_le32(split);
3234 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
3235 ext4_ext_store_pblock(ex2, newblock);
3236 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3237 ext4_ext_mark_unwritten(ex2);
3238
3239 err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3240 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3241 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3242 if (split_flag & EXT4_EXT_DATA_VALID1) {
3243 err = ext4_ext_zeroout(inode, ex2);
3244 zero_ex.ee_block = ex2->ee_block;
3245 zero_ex.ee_len = cpu_to_le16(
3246 ext4_ext_get_actual_len(ex2));
3247 ext4_ext_store_pblock(&zero_ex,
3248 ext4_ext_pblock(ex2));
3249 } else {
3250 err = ext4_ext_zeroout(inode, ex);
3251 zero_ex.ee_block = ex->ee_block;
3252 zero_ex.ee_len = cpu_to_le16(
3253 ext4_ext_get_actual_len(ex));
3254 ext4_ext_store_pblock(&zero_ex,
3255 ext4_ext_pblock(ex));
3256 }
3257 } else {
3258 err = ext4_ext_zeroout(inode, &orig_ex);
3259 zero_ex.ee_block = orig_ex.ee_block;
3260 zero_ex.ee_len = cpu_to_le16(
3261 ext4_ext_get_actual_len(&orig_ex));
3262 ext4_ext_store_pblock(&zero_ex,
3263 ext4_ext_pblock(&orig_ex));
3264 }
3265
3266 if (err)
3267 goto fix_extent_len;
3268 /* update the extent length and mark as initialized */
3269 ex->ee_len = cpu_to_le16(ee_len);
3270 ext4_ext_try_to_merge(handle, inode, path, ex);
3271 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3272 if (err)
3273 goto fix_extent_len;
3274
3275 /* update extent status tree */
3276 err = ext4_zeroout_es(inode, &zero_ex);
3277
3278 goto out;
3279 } else if (err)
3280 goto fix_extent_len;
3281
3282out:
3283 ext4_ext_show_leaf(inode, path);
3284 return err;
3285
3286fix_extent_len:
3287 ex->ee_len = orig_ex.ee_len;
3288 ext4_ext_dirty(handle, inode, path + path->p_depth);
3289 return err;
3290}
3291
3292/*
3293 * ext4_split_extents() splits an extent and mark extent which is covered
3294 * by @map as split_flags indicates
3295 *
3296 * It may result in splitting the extent into multiple extents (up to three)
3297 * There are three possibilities:
3298 * a> There is no split required
3299 * b> Splits in two extents: Split is happening at either end of the extent
3300 * c> Splits in three extents: Somone is splitting in middle of the extent
3301 *
3302 */
3303static int ext4_split_extent(handle_t *handle,
3304 struct inode *inode,
3305 struct ext4_ext_path **ppath,
3306 struct ext4_map_blocks *map,
3307 int split_flag,
3308 int flags)
3309{
3310 struct ext4_ext_path *path = *ppath;
3311 ext4_lblk_t ee_block;
3312 struct ext4_extent *ex;
3313 unsigned int ee_len, depth;
3314 int err = 0;
3315 int unwritten;
3316 int split_flag1, flags1;
3317 int allocated = map->m_len;
3318
3319 depth = ext_depth(inode);
3320 ex = path[depth].p_ext;
3321 ee_block = le32_to_cpu(ex->ee_block);
3322 ee_len = ext4_ext_get_actual_len(ex);
3323 unwritten = ext4_ext_is_unwritten(ex);
3324
3325 if (map->m_lblk + map->m_len < ee_block + ee_len) {
3326 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3327 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3328 if (unwritten)
3329 split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3330 EXT4_EXT_MARK_UNWRIT2;
3331 if (split_flag & EXT4_EXT_DATA_VALID2)
3332 split_flag1 |= EXT4_EXT_DATA_VALID1;
3333 err = ext4_split_extent_at(handle, inode, ppath,
3334 map->m_lblk + map->m_len, split_flag1, flags1);
3335 if (err)
3336 goto out;
3337 } else {
3338 allocated = ee_len - (map->m_lblk - ee_block);
3339 }
3340 /*
3341 * Update path is required because previous ext4_split_extent_at() may
3342 * result in split of original leaf or extent zeroout.
3343 */
3344 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3345 if (IS_ERR(path))
3346 return PTR_ERR(path);
3347 depth = ext_depth(inode);
3348 ex = path[depth].p_ext;
3349 if (!ex) {
3350 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3351 (unsigned long) map->m_lblk);
3352 return -EFSCORRUPTED;
3353 }
3354 unwritten = ext4_ext_is_unwritten(ex);
3355 split_flag1 = 0;
3356
3357 if (map->m_lblk >= ee_block) {
3358 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3359 if (unwritten) {
3360 split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3361 split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3362 EXT4_EXT_MARK_UNWRIT2);
3363 }
3364 err = ext4_split_extent_at(handle, inode, ppath,
3365 map->m_lblk, split_flag1, flags);
3366 if (err)
3367 goto out;
3368 }
3369
3370 ext4_ext_show_leaf(inode, path);
3371out:
3372 return err ? err : allocated;
3373}
3374
3375/*
3376 * This function is called by ext4_ext_map_blocks() if someone tries to write
3377 * to an unwritten extent. It may result in splitting the unwritten
3378 * extent into multiple extents (up to three - one initialized and two
3379 * unwritten).
3380 * There are three possibilities:
3381 * a> There is no split required: Entire extent should be initialized
3382 * b> Splits in two extents: Write is happening at either end of the extent
3383 * c> Splits in three extents: Somone is writing in middle of the extent
3384 *
3385 * Pre-conditions:
3386 * - The extent pointed to by 'path' is unwritten.
3387 * - The extent pointed to by 'path' contains a superset
3388 * of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3389 *
3390 * Post-conditions on success:
3391 * - the returned value is the number of blocks beyond map->l_lblk
3392 * that are allocated and initialized.
3393 * It is guaranteed to be >= map->m_len.
3394 */
3395static int ext4_ext_convert_to_initialized(handle_t *handle,
3396 struct inode *inode,
3397 struct ext4_map_blocks *map,
3398 struct ext4_ext_path **ppath,
3399 int flags)
3400{
3401 struct ext4_ext_path *path = *ppath;
3402 struct ext4_sb_info *sbi;
3403 struct ext4_extent_header *eh;
3404 struct ext4_map_blocks split_map;
3405 struct ext4_extent zero_ex1, zero_ex2;
3406 struct ext4_extent *ex, *abut_ex;
3407 ext4_lblk_t ee_block, eof_block;
3408 unsigned int ee_len, depth, map_len = map->m_len;
3409 int allocated = 0, max_zeroout = 0;
3410 int err = 0;
3411 int split_flag = EXT4_EXT_DATA_VALID2;
3412
3413 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3414 "block %llu, max_blocks %u\n", inode->i_ino,
3415 (unsigned long long)map->m_lblk, map_len);
3416
3417 sbi = EXT4_SB(inode->i_sb);
3418 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3419 inode->i_sb->s_blocksize_bits;
3420 if (eof_block < map->m_lblk + map_len)
3421 eof_block = map->m_lblk + map_len;
3422
3423 depth = ext_depth(inode);
3424 eh = path[depth].p_hdr;
3425 ex = path[depth].p_ext;
3426 ee_block = le32_to_cpu(ex->ee_block);
3427 ee_len = ext4_ext_get_actual_len(ex);
3428 zero_ex1.ee_len = 0;
3429 zero_ex2.ee_len = 0;
3430
3431 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3432
3433 /* Pre-conditions */
3434 BUG_ON(!ext4_ext_is_unwritten(ex));
3435 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3436
3437 /*
3438 * Attempt to transfer newly initialized blocks from the currently
3439 * unwritten extent to its neighbor. This is much cheaper
3440 * than an insertion followed by a merge as those involve costly
3441 * memmove() calls. Transferring to the left is the common case in
3442 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3443 * followed by append writes.
3444 *
3445 * Limitations of the current logic:
3446 * - L1: we do not deal with writes covering the whole extent.
3447 * This would require removing the extent if the transfer
3448 * is possible.
3449 * - L2: we only attempt to merge with an extent stored in the
3450 * same extent tree node.
3451 */
3452 if ((map->m_lblk == ee_block) &&
3453 /* See if we can merge left */
3454 (map_len < ee_len) && /*L1*/
3455 (ex > EXT_FIRST_EXTENT(eh))) { /*L2*/
3456 ext4_lblk_t prev_lblk;
3457 ext4_fsblk_t prev_pblk, ee_pblk;
3458 unsigned int prev_len;
3459
3460 abut_ex = ex - 1;
3461 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3462 prev_len = ext4_ext_get_actual_len(abut_ex);
3463 prev_pblk = ext4_ext_pblock(abut_ex);
3464 ee_pblk = ext4_ext_pblock(ex);
3465
3466 /*
3467 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3468 * upon those conditions:
3469 * - C1: abut_ex is initialized,
3470 * - C2: abut_ex is logically abutting ex,
3471 * - C3: abut_ex is physically abutting ex,
3472 * - C4: abut_ex can receive the additional blocks without
3473 * overflowing the (initialized) length limit.
3474 */
3475 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3476 ((prev_lblk + prev_len) == ee_block) && /*C2*/
3477 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/
3478 (prev_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3479 err = ext4_ext_get_access(handle, inode, path + depth);
3480 if (err)
3481 goto out;
3482
3483 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3484 map, ex, abut_ex);
3485
3486 /* Shift the start of ex by 'map_len' blocks */
3487 ex->ee_block = cpu_to_le32(ee_block + map_len);
3488 ext4_ext_store_pblock(ex, ee_pblk + map_len);
3489 ex->ee_len = cpu_to_le16(ee_len - map_len);
3490 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3491
3492 /* Extend abut_ex by 'map_len' blocks */
3493 abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3494
3495 /* Result: number of initialized blocks past m_lblk */
3496 allocated = map_len;
3497 }
3498 } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3499 (map_len < ee_len) && /*L1*/
3500 ex < EXT_LAST_EXTENT(eh)) { /*L2*/
3501 /* See if we can merge right */
3502 ext4_lblk_t next_lblk;
3503 ext4_fsblk_t next_pblk, ee_pblk;
3504 unsigned int next_len;
3505
3506 abut_ex = ex + 1;
3507 next_lblk = le32_to_cpu(abut_ex->ee_block);
3508 next_len = ext4_ext_get_actual_len(abut_ex);
3509 next_pblk = ext4_ext_pblock(abut_ex);
3510 ee_pblk = ext4_ext_pblock(ex);
3511
3512 /*
3513 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3514 * upon those conditions:
3515 * - C1: abut_ex is initialized,
3516 * - C2: abut_ex is logically abutting ex,
3517 * - C3: abut_ex is physically abutting ex,
3518 * - C4: abut_ex can receive the additional blocks without
3519 * overflowing the (initialized) length limit.
3520 */
3521 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3522 ((map->m_lblk + map_len) == next_lblk) && /*C2*/
3523 ((ee_pblk + ee_len) == next_pblk) && /*C3*/
3524 (next_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3525 err = ext4_ext_get_access(handle, inode, path + depth);
3526 if (err)
3527 goto out;
3528
3529 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3530 map, ex, abut_ex);
3531
3532 /* Shift the start of abut_ex by 'map_len' blocks */
3533 abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3534 ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3535 ex->ee_len = cpu_to_le16(ee_len - map_len);
3536 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3537
3538 /* Extend abut_ex by 'map_len' blocks */
3539 abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3540
3541 /* Result: number of initialized blocks past m_lblk */
3542 allocated = map_len;
3543 }
3544 }
3545 if (allocated) {
3546 /* Mark the block containing both extents as dirty */
3547 ext4_ext_dirty(handle, inode, path + depth);
3548
3549 /* Update path to point to the right extent */
3550 path[depth].p_ext = abut_ex;
3551 goto out;
3552 } else
3553 allocated = ee_len - (map->m_lblk - ee_block);
3554
3555 WARN_ON(map->m_lblk < ee_block);
3556 /*
3557 * It is safe to convert extent to initialized via explicit
3558 * zeroout only if extent is fully inside i_size or new_size.
3559 */
3560 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3561
3562 if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3563 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3564 (inode->i_sb->s_blocksize_bits - 10);
3565
3566 if (ext4_encrypted_inode(inode))
3567 max_zeroout = 0;
3568
3569 /*
3570 * five cases:
3571 * 1. split the extent into three extents.
3572 * 2. split the extent into two extents, zeroout the head of the first
3573 * extent.
3574 * 3. split the extent into two extents, zeroout the tail of the second
3575 * extent.
3576 * 4. split the extent into two extents with out zeroout.
3577 * 5. no splitting needed, just possibly zeroout the head and / or the
3578 * tail of the extent.
3579 */
3580 split_map.m_lblk = map->m_lblk;
3581 split_map.m_len = map->m_len;
3582
3583 if (max_zeroout && (allocated > split_map.m_len)) {
3584 if (allocated <= max_zeroout) {
3585 /* case 3 or 5 */
3586 zero_ex1.ee_block =
3587 cpu_to_le32(split_map.m_lblk +
3588 split_map.m_len);
3589 zero_ex1.ee_len =
3590 cpu_to_le16(allocated - split_map.m_len);
3591 ext4_ext_store_pblock(&zero_ex1,
3592 ext4_ext_pblock(ex) + split_map.m_lblk +
3593 split_map.m_len - ee_block);
3594 err = ext4_ext_zeroout(inode, &zero_ex1);
3595 if (err)
3596 goto out;
3597 split_map.m_len = allocated;
3598 }
3599 if (split_map.m_lblk - ee_block + split_map.m_len <
3600 max_zeroout) {
3601 /* case 2 or 5 */
3602 if (split_map.m_lblk != ee_block) {
3603 zero_ex2.ee_block = ex->ee_block;
3604 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3605 ee_block);
3606 ext4_ext_store_pblock(&zero_ex2,
3607 ext4_ext_pblock(ex));
3608 err = ext4_ext_zeroout(inode, &zero_ex2);
3609 if (err)
3610 goto out;
3611 }
3612
3613 split_map.m_len += split_map.m_lblk - ee_block;
3614 split_map.m_lblk = ee_block;
3615 allocated = map->m_len;
3616 }
3617 }
3618
3619 err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3620 flags);
3621 if (err > 0)
3622 err = 0;
3623out:
3624 /* If we have gotten a failure, don't zero out status tree */
3625 if (!err) {
3626 err = ext4_zeroout_es(inode, &zero_ex1);
3627 if (!err)
3628 err = ext4_zeroout_es(inode, &zero_ex2);
3629 }
3630 return err ? err : allocated;
3631}
3632
3633/*
3634 * This function is called by ext4_ext_map_blocks() from
3635 * ext4_get_blocks_dio_write() when DIO to write
3636 * to an unwritten extent.
3637 *
3638 * Writing to an unwritten extent may result in splitting the unwritten
3639 * extent into multiple initialized/unwritten extents (up to three)
3640 * There are three possibilities:
3641 * a> There is no split required: Entire extent should be unwritten
3642 * b> Splits in two extents: Write is happening at either end of the extent
3643 * c> Splits in three extents: Somone is writing in middle of the extent
3644 *
3645 * This works the same way in the case of initialized -> unwritten conversion.
3646 *
3647 * One of more index blocks maybe needed if the extent tree grow after
3648 * the unwritten extent split. To prevent ENOSPC occur at the IO
3649 * complete, we need to split the unwritten extent before DIO submit
3650 * the IO. The unwritten extent called at this time will be split
3651 * into three unwritten extent(at most). After IO complete, the part
3652 * being filled will be convert to initialized by the end_io callback function
3653 * via ext4_convert_unwritten_extents().
3654 *
3655 * Returns the size of unwritten extent to be written on success.
3656 */
3657static int ext4_split_convert_extents(handle_t *handle,
3658 struct inode *inode,
3659 struct ext4_map_blocks *map,
3660 struct ext4_ext_path **ppath,
3661 int flags)
3662{
3663 struct ext4_ext_path *path = *ppath;
3664 ext4_lblk_t eof_block;
3665 ext4_lblk_t ee_block;
3666 struct ext4_extent *ex;
3667 unsigned int ee_len;
3668 int split_flag = 0, depth;
3669
3670 ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3671 __func__, inode->i_ino,
3672 (unsigned long long)map->m_lblk, map->m_len);
3673
3674 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3675 inode->i_sb->s_blocksize_bits;
3676 if (eof_block < map->m_lblk + map->m_len)
3677 eof_block = map->m_lblk + map->m_len;
3678 /*
3679 * It is safe to convert extent to initialized via explicit
3680 * zeroout only if extent is fully insde i_size or new_size.
3681 */
3682 depth = ext_depth(inode);
3683 ex = path[depth].p_ext;
3684 ee_block = le32_to_cpu(ex->ee_block);
3685 ee_len = ext4_ext_get_actual_len(ex);
3686
3687 /* Convert to unwritten */
3688 if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3689 split_flag |= EXT4_EXT_DATA_VALID1;
3690 /* Convert to initialized */
3691 } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3692 split_flag |= ee_block + ee_len <= eof_block ?
3693 EXT4_EXT_MAY_ZEROOUT : 0;
3694 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3695 }
3696 flags |= EXT4_GET_BLOCKS_PRE_IO;
3697 return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3698}
3699
3700static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3701 struct inode *inode,
3702 struct ext4_map_blocks *map,
3703 struct ext4_ext_path **ppath)
3704{
3705 struct ext4_ext_path *path = *ppath;
3706 struct ext4_extent *ex;
3707 ext4_lblk_t ee_block;
3708 unsigned int ee_len;
3709 int depth;
3710 int err = 0;
3711
3712 depth = ext_depth(inode);
3713 ex = path[depth].p_ext;
3714 ee_block = le32_to_cpu(ex->ee_block);
3715 ee_len = ext4_ext_get_actual_len(ex);
3716
3717 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3718 "block %llu, max_blocks %u\n", inode->i_ino,
3719 (unsigned long long)ee_block, ee_len);
3720
3721 /* If extent is larger than requested it is a clear sign that we still
3722 * have some extent state machine issues left. So extent_split is still
3723 * required.
3724 * TODO: Once all related issues will be fixed this situation should be
3725 * illegal.
3726 */
3727 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3728#ifdef EXT4_DEBUG
3729 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3730 " len %u; IO logical block %llu, len %u",
3731 inode->i_ino, (unsigned long long)ee_block, ee_len,
3732 (unsigned long long)map->m_lblk, map->m_len);
3733#endif
3734 err = ext4_split_convert_extents(handle, inode, map, ppath,
3735 EXT4_GET_BLOCKS_CONVERT);
3736 if (err < 0)
3737 return err;
3738 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3739 if (IS_ERR(path))
3740 return PTR_ERR(path);
3741 depth = ext_depth(inode);
3742 ex = path[depth].p_ext;
3743 }
3744
3745 err = ext4_ext_get_access(handle, inode, path + depth);
3746 if (err)
3747 goto out;
3748 /* first mark the extent as initialized */
3749 ext4_ext_mark_initialized(ex);
3750
3751 /* note: ext4_ext_correct_indexes() isn't needed here because
3752 * borders are not changed
3753 */
3754 ext4_ext_try_to_merge(handle, inode, path, ex);
3755
3756 /* Mark modified extent as dirty */
3757 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3758out:
3759 ext4_ext_show_leaf(inode, path);
3760 return err;
3761}
3762
3763/*
3764 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3765 */
3766static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3767 ext4_lblk_t lblk,
3768 struct ext4_ext_path *path,
3769 unsigned int len)
3770{
3771 int i, depth;
3772 struct ext4_extent_header *eh;
3773 struct ext4_extent *last_ex;
3774
3775 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3776 return 0;
3777
3778 depth = ext_depth(inode);
3779 eh = path[depth].p_hdr;
3780
3781 /*
3782 * We're going to remove EOFBLOCKS_FL entirely in future so we
3783 * do not care for this case anymore. Simply remove the flag
3784 * if there are no extents.
3785 */
3786 if (unlikely(!eh->eh_entries))
3787 goto out;
3788 last_ex = EXT_LAST_EXTENT(eh);
3789 /*
3790 * We should clear the EOFBLOCKS_FL flag if we are writing the
3791 * last block in the last extent in the file. We test this by
3792 * first checking to see if the caller to
3793 * ext4_ext_get_blocks() was interested in the last block (or
3794 * a block beyond the last block) in the current extent. If
3795 * this turns out to be false, we can bail out from this
3796 * function immediately.
3797 */
3798 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3799 ext4_ext_get_actual_len(last_ex))
3800 return 0;
3801 /*
3802 * If the caller does appear to be planning to write at or
3803 * beyond the end of the current extent, we then test to see
3804 * if the current extent is the last extent in the file, by
3805 * checking to make sure it was reached via the rightmost node
3806 * at each level of the tree.
3807 */
3808 for (i = depth-1; i >= 0; i--)
3809 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3810 return 0;
3811out:
3812 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3813 return ext4_mark_inode_dirty(handle, inode);
3814}
3815
3816/**
3817 * ext4_find_delalloc_range: find delayed allocated block in the given range.
3818 *
3819 * Return 1 if there is a delalloc block in the range, otherwise 0.
3820 */
3821int ext4_find_delalloc_range(struct inode *inode,
3822 ext4_lblk_t lblk_start,
3823 ext4_lblk_t lblk_end)
3824{
3825 struct extent_status es;
3826
3827 ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3828 if (es.es_len == 0)
3829 return 0; /* there is no delay extent in this tree */
3830 else if (es.es_lblk <= lblk_start &&
3831 lblk_start < es.es_lblk + es.es_len)
3832 return 1;
3833 else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3834 return 1;
3835 else
3836 return 0;
3837}
3838
3839int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3840{
3841 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3842 ext4_lblk_t lblk_start, lblk_end;
3843 lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3844 lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3845
3846 return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3847}
3848
3849/**
3850 * Determines how many complete clusters (out of those specified by the 'map')
3851 * are under delalloc and were reserved quota for.
3852 * This function is called when we are writing out the blocks that were
3853 * originally written with their allocation delayed, but then the space was
3854 * allocated using fallocate() before the delayed allocation could be resolved.
3855 * The cases to look for are:
3856 * ('=' indicated delayed allocated blocks
3857 * '-' indicates non-delayed allocated blocks)
3858 * (a) partial clusters towards beginning and/or end outside of allocated range
3859 * are not delalloc'ed.
3860 * Ex:
3861 * |----c---=|====c====|====c====|===-c----|
3862 * |++++++ allocated ++++++|
3863 * ==> 4 complete clusters in above example
3864 *
3865 * (b) partial cluster (outside of allocated range) towards either end is
3866 * marked for delayed allocation. In this case, we will exclude that
3867 * cluster.
3868 * Ex:
3869 * |----====c========|========c========|
3870 * |++++++ allocated ++++++|
3871 * ==> 1 complete clusters in above example
3872 *
3873 * Ex:
3874 * |================c================|
3875 * |++++++ allocated ++++++|
3876 * ==> 0 complete clusters in above example
3877 *
3878 * The ext4_da_update_reserve_space will be called only if we
3879 * determine here that there were some "entire" clusters that span
3880 * this 'allocated' range.
3881 * In the non-bigalloc case, this function will just end up returning num_blks
3882 * without ever calling ext4_find_delalloc_range.
3883 */
3884static unsigned int
3885get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3886 unsigned int num_blks)
3887{
3888 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3889 ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3890 ext4_lblk_t lblk_from, lblk_to, c_offset;
3891 unsigned int allocated_clusters = 0;
3892
3893 alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3894 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3895
3896 /* max possible clusters for this allocation */
3897 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3898
3899 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3900
3901 /* Check towards left side */
3902 c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3903 if (c_offset) {
3904 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3905 lblk_to = lblk_from + c_offset - 1;
3906
3907 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3908 allocated_clusters--;
3909 }
3910
3911 /* Now check towards right. */
3912 c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3913 if (allocated_clusters && c_offset) {
3914 lblk_from = lblk_start + num_blks;
3915 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3916
3917 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3918 allocated_clusters--;
3919 }
3920
3921 return allocated_clusters;
3922}
3923
3924static int
3925convert_initialized_extent(handle_t *handle, struct inode *inode,
3926 struct ext4_map_blocks *map,
3927 struct ext4_ext_path **ppath,
3928 unsigned int allocated)
3929{
3930 struct ext4_ext_path *path = *ppath;
3931 struct ext4_extent *ex;
3932 ext4_lblk_t ee_block;
3933 unsigned int ee_len;
3934 int depth;
3935 int err = 0;
3936
3937 /*
3938 * Make sure that the extent is no bigger than we support with
3939 * unwritten extent
3940 */
3941 if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3942 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3943
3944 depth = ext_depth(inode);
3945 ex = path[depth].p_ext;
3946 ee_block = le32_to_cpu(ex->ee_block);
3947 ee_len = ext4_ext_get_actual_len(ex);
3948
3949 ext_debug("%s: inode %lu, logical"
3950 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3951 (unsigned long long)ee_block, ee_len);
3952
3953 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3954 err = ext4_split_convert_extents(handle, inode, map, ppath,
3955 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3956 if (err < 0)
3957 return err;
3958 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3959 if (IS_ERR(path))
3960 return PTR_ERR(path);
3961 depth = ext_depth(inode);
3962 ex = path[depth].p_ext;
3963 if (!ex) {
3964 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3965 (unsigned long) map->m_lblk);
3966 return -EFSCORRUPTED;
3967 }
3968 }
3969
3970 err = ext4_ext_get_access(handle, inode, path + depth);
3971 if (err)
3972 return err;
3973 /* first mark the extent as unwritten */
3974 ext4_ext_mark_unwritten(ex);
3975
3976 /* note: ext4_ext_correct_indexes() isn't needed here because
3977 * borders are not changed
3978 */
3979 ext4_ext_try_to_merge(handle, inode, path, ex);
3980
3981 /* Mark modified extent as dirty */
3982 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3983 if (err)
3984 return err;
3985 ext4_ext_show_leaf(inode, path);
3986
3987 ext4_update_inode_fsync_trans(handle, inode, 1);
3988 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
3989 if (err)
3990 return err;
3991 map->m_flags |= EXT4_MAP_UNWRITTEN;
3992 if (allocated > map->m_len)
3993 allocated = map->m_len;
3994 map->m_len = allocated;
3995 return allocated;
3996}
3997
3998static int
3999ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4000 struct ext4_map_blocks *map,
4001 struct ext4_ext_path **ppath, int flags,
4002 unsigned int allocated, ext4_fsblk_t newblock)
4003{
4004 struct ext4_ext_path *path = *ppath;
4005 int ret = 0;
4006 int err = 0;
4007
4008 ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4009 "block %llu, max_blocks %u, flags %x, allocated %u\n",
4010 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4011 flags, allocated);
4012 ext4_ext_show_leaf(inode, path);
4013
4014 /*
4015 * When writing into unwritten space, we should not fail to
4016 * allocate metadata blocks for the new extent block if needed.
4017 */
4018 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4019
4020 trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4021 allocated, newblock);
4022
4023 /* get_block() before submit the IO, split the extent */
4024 if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4025 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4026 flags | EXT4_GET_BLOCKS_CONVERT);
4027 if (ret <= 0)
4028 goto out;
4029 map->m_flags |= EXT4_MAP_UNWRITTEN;
4030 goto out;
4031 }
4032 /* IO end_io complete, convert the filled extent to written */
4033 if (flags & EXT4_GET_BLOCKS_CONVERT) {
4034 if (flags & EXT4_GET_BLOCKS_ZERO) {
4035 if (allocated > map->m_len)
4036 allocated = map->m_len;
4037 err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4038 allocated);
4039 if (err < 0)
4040 goto out2;
4041 }
4042 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4043 ppath);
4044 if (ret >= 0) {
4045 ext4_update_inode_fsync_trans(handle, inode, 1);
4046 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4047 path, map->m_len);
4048 } else
4049 err = ret;
4050 map->m_flags |= EXT4_MAP_MAPPED;
4051 map->m_pblk = newblock;
4052 if (allocated > map->m_len)
4053 allocated = map->m_len;
4054 map->m_len = allocated;
4055 goto out2;
4056 }
4057 /* buffered IO case */
4058 /*
4059 * repeat fallocate creation request
4060 * we already have an unwritten extent
4061 */
4062 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4063 map->m_flags |= EXT4_MAP_UNWRITTEN;
4064 goto map_out;
4065 }
4066
4067 /* buffered READ or buffered write_begin() lookup */
4068 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4069 /*
4070 * We have blocks reserved already. We
4071 * return allocated blocks so that delalloc
4072 * won't do block reservation for us. But
4073 * the buffer head will be unmapped so that
4074 * a read from the block returns 0s.
4075 */
4076 map->m_flags |= EXT4_MAP_UNWRITTEN;
4077 goto out1;
4078 }
4079
4080 /* buffered write, writepage time, convert*/
4081 ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4082 if (ret >= 0)
4083 ext4_update_inode_fsync_trans(handle, inode, 1);
4084out:
4085 if (ret <= 0) {
4086 err = ret;
4087 goto out2;
4088 } else
4089 allocated = ret;
4090 map->m_flags |= EXT4_MAP_NEW;
4091 /*
4092 * if we allocated more blocks than requested
4093 * we need to make sure we unmap the extra block
4094 * allocated. The actual needed block will get
4095 * unmapped later when we find the buffer_head marked
4096 * new.
4097 */
4098 if (allocated > map->m_len) {
4099 clean_bdev_aliases(inode->i_sb->s_bdev, newblock + map->m_len,
4100 allocated - map->m_len);
4101 allocated = map->m_len;
4102 }
4103 map->m_len = allocated;
4104
4105 /*
4106 * If we have done fallocate with the offset that is already
4107 * delayed allocated, we would have block reservation
4108 * and quota reservation done in the delayed write path.
4109 * But fallocate would have already updated quota and block
4110 * count for this offset. So cancel these reservation
4111 */
4112 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4113 unsigned int reserved_clusters;
4114 reserved_clusters = get_reserved_cluster_alloc(inode,
4115 map->m_lblk, map->m_len);
4116 if (reserved_clusters)
4117 ext4_da_update_reserve_space(inode,
4118 reserved_clusters,
4119 0);
4120 }
4121
4122map_out:
4123 map->m_flags |= EXT4_MAP_MAPPED;
4124 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4125 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4126 map->m_len);
4127 if (err < 0)
4128 goto out2;
4129 }
4130out1:
4131 if (allocated > map->m_len)
4132 allocated = map->m_len;
4133 ext4_ext_show_leaf(inode, path);
4134 map->m_pblk = newblock;
4135 map->m_len = allocated;
4136out2:
4137 return err ? err : allocated;
4138}
4139
4140/*
4141 * get_implied_cluster_alloc - check to see if the requested
4142 * allocation (in the map structure) overlaps with a cluster already
4143 * allocated in an extent.
4144 * @sb The filesystem superblock structure
4145 * @map The requested lblk->pblk mapping
4146 * @ex The extent structure which might contain an implied
4147 * cluster allocation
4148 *
4149 * This function is called by ext4_ext_map_blocks() after we failed to
4150 * find blocks that were already in the inode's extent tree. Hence,
4151 * we know that the beginning of the requested region cannot overlap
4152 * the extent from the inode's extent tree. There are three cases we
4153 * want to catch. The first is this case:
4154 *
4155 * |--- cluster # N--|
4156 * |--- extent ---| |---- requested region ---|
4157 * |==========|
4158 *
4159 * The second case that we need to test for is this one:
4160 *
4161 * |--------- cluster # N ----------------|
4162 * |--- requested region --| |------- extent ----|
4163 * |=======================|
4164 *
4165 * The third case is when the requested region lies between two extents
4166 * within the same cluster:
4167 * |------------- cluster # N-------------|
4168 * |----- ex -----| |---- ex_right ----|
4169 * |------ requested region ------|
4170 * |================|
4171 *
4172 * In each of the above cases, we need to set the map->m_pblk and
4173 * map->m_len so it corresponds to the return the extent labelled as
4174 * "|====|" from cluster #N, since it is already in use for data in
4175 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to
4176 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4177 * as a new "allocated" block region. Otherwise, we will return 0 and
4178 * ext4_ext_map_blocks() will then allocate one or more new clusters
4179 * by calling ext4_mb_new_blocks().
4180 */
4181static int get_implied_cluster_alloc(struct super_block *sb,
4182 struct ext4_map_blocks *map,
4183 struct ext4_extent *ex,
4184 struct ext4_ext_path *path)
4185{
4186 struct ext4_sb_info *sbi = EXT4_SB(sb);
4187 ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4188 ext4_lblk_t ex_cluster_start, ex_cluster_end;
4189 ext4_lblk_t rr_cluster_start;
4190 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4191 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4192 unsigned short ee_len = ext4_ext_get_actual_len(ex);
4193
4194 /* The extent passed in that we are trying to match */
4195 ex_cluster_start = EXT4_B2C(sbi, ee_block);
4196 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4197
4198 /* The requested region passed into ext4_map_blocks() */
4199 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4200
4201 if ((rr_cluster_start == ex_cluster_end) ||
4202 (rr_cluster_start == ex_cluster_start)) {
4203 if (rr_cluster_start == ex_cluster_end)
4204 ee_start += ee_len - 1;
4205 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4206 map->m_len = min(map->m_len,
4207 (unsigned) sbi->s_cluster_ratio - c_offset);
4208 /*
4209 * Check for and handle this case:
4210 *
4211 * |--------- cluster # N-------------|
4212 * |------- extent ----|
4213 * |--- requested region ---|
4214 * |===========|
4215 */
4216
4217 if (map->m_lblk < ee_block)
4218 map->m_len = min(map->m_len, ee_block - map->m_lblk);
4219
4220 /*
4221 * Check for the case where there is already another allocated
4222 * block to the right of 'ex' but before the end of the cluster.
4223 *
4224 * |------------- cluster # N-------------|
4225 * |----- ex -----| |---- ex_right ----|
4226 * |------ requested region ------|
4227 * |================|
4228 */
4229 if (map->m_lblk > ee_block) {
4230 ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4231 map->m_len = min(map->m_len, next - map->m_lblk);
4232 }
4233
4234 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4235 return 1;
4236 }
4237
4238 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4239 return 0;
4240}
4241
4242
4243/*
4244 * Block allocation/map/preallocation routine for extents based files
4245 *
4246 *
4247 * Need to be called with
4248 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4249 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4250 *
4251 * return > 0, number of of blocks already mapped/allocated
4252 * if create == 0 and these are pre-allocated blocks
4253 * buffer head is unmapped
4254 * otherwise blocks are mapped
4255 *
4256 * return = 0, if plain look up failed (blocks have not been allocated)
4257 * buffer head is unmapped
4258 *
4259 * return < 0, error case.
4260 */
4261int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4262 struct ext4_map_blocks *map, int flags)
4263{
4264 struct ext4_ext_path *path = NULL;
4265 struct ext4_extent newex, *ex, *ex2;
4266 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4267 ext4_fsblk_t newblock = 0;
4268 int free_on_err = 0, err = 0, depth, ret;
4269 unsigned int allocated = 0, offset = 0;
4270 unsigned int allocated_clusters = 0;
4271 struct ext4_allocation_request ar;
4272 ext4_lblk_t cluster_offset;
4273 bool map_from_cluster = false;
4274
4275 ext_debug("blocks %u/%u requested for inode %lu\n",
4276 map->m_lblk, map->m_len, inode->i_ino);
4277 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4278
4279 /* find extent for this block */
4280 path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4281 if (IS_ERR(path)) {
4282 err = PTR_ERR(path);
4283 path = NULL;
4284 goto out2;
4285 }
4286
4287 depth = ext_depth(inode);
4288
4289 /*
4290 * consistent leaf must not be empty;
4291 * this situation is possible, though, _during_ tree modification;
4292 * this is why assert can't be put in ext4_find_extent()
4293 */
4294 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4295 EXT4_ERROR_INODE(inode, "bad extent address "
4296 "lblock: %lu, depth: %d pblock %lld",
4297 (unsigned long) map->m_lblk, depth,
4298 path[depth].p_block);
4299 err = -EFSCORRUPTED;
4300 goto out2;
4301 }
4302
4303 ex = path[depth].p_ext;
4304 if (ex) {
4305 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4306 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4307 unsigned short ee_len;
4308
4309
4310 /*
4311 * unwritten extents are treated as holes, except that
4312 * we split out initialized portions during a write.
4313 */
4314 ee_len = ext4_ext_get_actual_len(ex);
4315
4316 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4317
4318 /* if found extent covers block, simply return it */
4319 if (in_range(map->m_lblk, ee_block, ee_len)) {
4320 newblock = map->m_lblk - ee_block + ee_start;
4321 /* number of remaining blocks in the extent */
4322 allocated = ee_len - (map->m_lblk - ee_block);
4323 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4324 ee_block, ee_len, newblock);
4325
4326 /*
4327 * If the extent is initialized check whether the
4328 * caller wants to convert it to unwritten.
4329 */
4330 if ((!ext4_ext_is_unwritten(ex)) &&
4331 (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4332 allocated = convert_initialized_extent(
4333 handle, inode, map, &path,
4334 allocated);
4335 goto out2;
4336 } else if (!ext4_ext_is_unwritten(ex))
4337 goto out;
4338
4339 ret = ext4_ext_handle_unwritten_extents(
4340 handle, inode, map, &path, flags,
4341 allocated, newblock);
4342 if (ret < 0)
4343 err = ret;
4344 else
4345 allocated = ret;
4346 goto out2;
4347 }
4348 }
4349
4350 /*
4351 * requested block isn't allocated yet;
4352 * we couldn't try to create block if create flag is zero
4353 */
4354 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4355 ext4_lblk_t hole_start, hole_len;
4356
4357 hole_start = map->m_lblk;
4358 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4359 /*
4360 * put just found gap into cache to speed up
4361 * subsequent requests
4362 */
4363 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4364
4365 /* Update hole_len to reflect hole size after map->m_lblk */
4366 if (hole_start != map->m_lblk)
4367 hole_len -= map->m_lblk - hole_start;
4368 map->m_pblk = 0;
4369 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4370
4371 goto out2;
4372 }
4373
4374 /*
4375 * Okay, we need to do block allocation.
4376 */
4377 newex.ee_block = cpu_to_le32(map->m_lblk);
4378 cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4379
4380 /*
4381 * If we are doing bigalloc, check to see if the extent returned
4382 * by ext4_find_extent() implies a cluster we can use.
4383 */
4384 if (cluster_offset && ex &&
4385 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4386 ar.len = allocated = map->m_len;
4387 newblock = map->m_pblk;
4388 map_from_cluster = true;
4389 goto got_allocated_blocks;
4390 }
4391
4392 /* find neighbour allocated blocks */
4393 ar.lleft = map->m_lblk;
4394 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4395 if (err)
4396 goto out2;
4397 ar.lright = map->m_lblk;
4398 ex2 = NULL;
4399 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4400 if (err)
4401 goto out2;
4402
4403 /* Check if the extent after searching to the right implies a
4404 * cluster we can use. */
4405 if ((sbi->s_cluster_ratio > 1) && ex2 &&
4406 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4407 ar.len = allocated = map->m_len;
4408 newblock = map->m_pblk;
4409 map_from_cluster = true;
4410 goto got_allocated_blocks;
4411 }
4412
4413 /*
4414 * See if request is beyond maximum number of blocks we can have in
4415 * a single extent. For an initialized extent this limit is
4416 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4417 * EXT_UNWRITTEN_MAX_LEN.
4418 */
4419 if (map->m_len > EXT_INIT_MAX_LEN &&
4420 !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4421 map->m_len = EXT_INIT_MAX_LEN;
4422 else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4423 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4424 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4425
4426 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4427 newex.ee_len = cpu_to_le16(map->m_len);
4428 err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4429 if (err)
4430 allocated = ext4_ext_get_actual_len(&newex);
4431 else
4432 allocated = map->m_len;
4433
4434 /* allocate new block */
4435 ar.inode = inode;
4436 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4437 ar.logical = map->m_lblk;
4438 /*
4439 * We calculate the offset from the beginning of the cluster
4440 * for the logical block number, since when we allocate a
4441 * physical cluster, the physical block should start at the
4442 * same offset from the beginning of the cluster. This is
4443 * needed so that future calls to get_implied_cluster_alloc()
4444 * work correctly.
4445 */
4446 offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4447 ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4448 ar.goal -= offset;
4449 ar.logical -= offset;
4450 if (S_ISREG(inode->i_mode))
4451 ar.flags = EXT4_MB_HINT_DATA;
4452 else
4453 /* disable in-core preallocation for non-regular files */
4454 ar.flags = 0;
4455 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4456 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4457 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4458 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4459 if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4460 ar.flags |= EXT4_MB_USE_RESERVED;
4461 newblock = ext4_mb_new_blocks(handle, &ar, &err);
4462 if (!newblock)
4463 goto out2;
4464 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4465 ar.goal, newblock, allocated);
4466 free_on_err = 1;
4467 allocated_clusters = ar.len;
4468 ar.len = EXT4_C2B(sbi, ar.len) - offset;
4469 if (ar.len > allocated)
4470 ar.len = allocated;
4471
4472got_allocated_blocks:
4473 /* try to insert new extent into found leaf and return */
4474 ext4_ext_store_pblock(&newex, newblock + offset);
4475 newex.ee_len = cpu_to_le16(ar.len);
4476 /* Mark unwritten */
4477 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4478 ext4_ext_mark_unwritten(&newex);
4479 map->m_flags |= EXT4_MAP_UNWRITTEN;
4480 }
4481
4482 err = 0;
4483 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4484 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4485 path, ar.len);
4486 if (!err)
4487 err = ext4_ext_insert_extent(handle, inode, &path,
4488 &newex, flags);
4489
4490 if (err && free_on_err) {
4491 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4492 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4493 /* free data blocks we just allocated */
4494 /* not a good idea to call discard here directly,
4495 * but otherwise we'd need to call it every free() */
4496 ext4_discard_preallocations(inode);
4497 ext4_free_blocks(handle, inode, NULL, newblock,
4498 EXT4_C2B(sbi, allocated_clusters), fb_flags);
4499 goto out2;
4500 }
4501
4502 /* previous routine could use block we allocated */
4503 newblock = ext4_ext_pblock(&newex);
4504 allocated = ext4_ext_get_actual_len(&newex);
4505 if (allocated > map->m_len)
4506 allocated = map->m_len;
4507 map->m_flags |= EXT4_MAP_NEW;
4508
4509 /*
4510 * Update reserved blocks/metadata blocks after successful
4511 * block allocation which had been deferred till now.
4512 */
4513 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4514 unsigned int reserved_clusters;
4515 /*
4516 * Check how many clusters we had reserved this allocated range
4517 */
4518 reserved_clusters = get_reserved_cluster_alloc(inode,
4519 map->m_lblk, allocated);
4520 if (!map_from_cluster) {
4521 BUG_ON(allocated_clusters < reserved_clusters);
4522 if (reserved_clusters < allocated_clusters) {
4523 struct ext4_inode_info *ei = EXT4_I(inode);
4524 int reservation = allocated_clusters -
4525 reserved_clusters;
4526 /*
4527 * It seems we claimed few clusters outside of
4528 * the range of this allocation. We should give
4529 * it back to the reservation pool. This can
4530 * happen in the following case:
4531 *
4532 * * Suppose s_cluster_ratio is 4 (i.e., each
4533 * cluster has 4 blocks. Thus, the clusters
4534 * are [0-3],[4-7],[8-11]...
4535 * * First comes delayed allocation write for
4536 * logical blocks 10 & 11. Since there were no
4537 * previous delayed allocated blocks in the
4538 * range [8-11], we would reserve 1 cluster
4539 * for this write.
4540 * * Next comes write for logical blocks 3 to 8.
4541 * In this case, we will reserve 2 clusters
4542 * (for [0-3] and [4-7]; and not for [8-11] as
4543 * that range has a delayed allocated blocks.
4544 * Thus total reserved clusters now becomes 3.
4545 * * Now, during the delayed allocation writeout
4546 * time, we will first write blocks [3-8] and
4547 * allocate 3 clusters for writing these
4548 * blocks. Also, we would claim all these
4549 * three clusters above.
4550 * * Now when we come here to writeout the
4551 * blocks [10-11], we would expect to claim
4552 * the reservation of 1 cluster we had made
4553 * (and we would claim it since there are no
4554 * more delayed allocated blocks in the range
4555 * [8-11]. But our reserved cluster count had
4556 * already gone to 0.
4557 *
4558 * Thus, at the step 4 above when we determine
4559 * that there are still some unwritten delayed
4560 * allocated blocks outside of our current
4561 * block range, we should increment the
4562 * reserved clusters count so that when the
4563 * remaining blocks finally gets written, we
4564 * could claim them.
4565 */
4566 dquot_reserve_block(inode,
4567 EXT4_C2B(sbi, reservation));
4568 spin_lock(&ei->i_block_reservation_lock);
4569 ei->i_reserved_data_blocks += reservation;
4570 spin_unlock(&ei->i_block_reservation_lock);
4571 }
4572 /*
4573 * We will claim quota for all newly allocated blocks.
4574 * We're updating the reserved space *after* the
4575 * correction above so we do not accidentally free
4576 * all the metadata reservation because we might
4577 * actually need it later on.
4578 */
4579 ext4_da_update_reserve_space(inode, allocated_clusters,
4580 1);
4581 }
4582 }
4583
4584 /*
4585 * Cache the extent and update transaction to commit on fdatasync only
4586 * when it is _not_ an unwritten extent.
4587 */
4588 if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4589 ext4_update_inode_fsync_trans(handle, inode, 1);
4590 else
4591 ext4_update_inode_fsync_trans(handle, inode, 0);
4592out:
4593 if (allocated > map->m_len)
4594 allocated = map->m_len;
4595 ext4_ext_show_leaf(inode, path);
4596 map->m_flags |= EXT4_MAP_MAPPED;
4597 map->m_pblk = newblock;
4598 map->m_len = allocated;
4599out2:
4600 ext4_ext_drop_refs(path);
4601 kfree(path);
4602
4603 trace_ext4_ext_map_blocks_exit(inode, flags, map,
4604 err ? err : allocated);
4605 return err ? err : allocated;
4606}
4607
4608int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4609{
4610 struct super_block *sb = inode->i_sb;
4611 ext4_lblk_t last_block;
4612 int err = 0;
4613
4614 /*
4615 * TODO: optimization is possible here.
4616 * Probably we need not scan at all,
4617 * because page truncation is enough.
4618 */
4619
4620 /* we have to know where to truncate from in crash case */
4621 EXT4_I(inode)->i_disksize = inode->i_size;
4622 err = ext4_mark_inode_dirty(handle, inode);
4623 if (err)
4624 return err;
4625
4626 last_block = (inode->i_size + sb->s_blocksize - 1)
4627 >> EXT4_BLOCK_SIZE_BITS(sb);
4628retry:
4629 err = ext4_es_remove_extent(inode, last_block,
4630 EXT_MAX_BLOCKS - last_block);
4631 if (err == -ENOMEM) {
4632 cond_resched();
4633 congestion_wait(BLK_RW_ASYNC, HZ/50);
4634 goto retry;
4635 }
4636 if (err)
4637 return err;
4638 return ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4639}
4640
4641static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4642 ext4_lblk_t len, loff_t new_size,
4643 int flags)
4644{
4645 struct inode *inode = file_inode(file);
4646 handle_t *handle;
4647 int ret = 0;
4648 int ret2 = 0;
4649 int retries = 0;
4650 int depth = 0;
4651 struct ext4_map_blocks map;
4652 unsigned int credits;
4653 loff_t epos;
4654
4655 BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4656 map.m_lblk = offset;
4657 map.m_len = len;
4658 /*
4659 * Don't normalize the request if it can fit in one extent so
4660 * that it doesn't get unnecessarily split into multiple
4661 * extents.
4662 */
4663 if (len <= EXT_UNWRITTEN_MAX_LEN)
4664 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4665
4666 /*
4667 * credits to insert 1 extent into extent tree
4668 */
4669 credits = ext4_chunk_trans_blocks(inode, len);
4670 depth = ext_depth(inode);
4671
4672retry:
4673 while (ret >= 0 && len) {
4674 /*
4675 * Recalculate credits when extent tree depth changes.
4676 */
4677 if (depth != ext_depth(inode)) {
4678 credits = ext4_chunk_trans_blocks(inode, len);
4679 depth = ext_depth(inode);
4680 }
4681
4682 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4683 credits);
4684 if (IS_ERR(handle)) {
4685 ret = PTR_ERR(handle);
4686 break;
4687 }
4688 ret = ext4_map_blocks(handle, inode, &map, flags);
4689 if (ret <= 0) {
4690 ext4_debug("inode #%lu: block %u: len %u: "
4691 "ext4_ext_map_blocks returned %d",
4692 inode->i_ino, map.m_lblk,
4693 map.m_len, ret);
4694 ext4_mark_inode_dirty(handle, inode);
4695 ret2 = ext4_journal_stop(handle);
4696 break;
4697 }
4698 map.m_lblk += ret;
4699 map.m_len = len = len - ret;
4700 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4701 inode->i_ctime = current_time(inode);
4702 if (new_size) {
4703 if (epos > new_size)
4704 epos = new_size;
4705 if (ext4_update_inode_size(inode, epos) & 0x1)
4706 inode->i_mtime = inode->i_ctime;
4707 } else {
4708 if (epos > inode->i_size)
4709 ext4_set_inode_flag(inode,
4710 EXT4_INODE_EOFBLOCKS);
4711 }
4712 ext4_mark_inode_dirty(handle, inode);
4713 ext4_update_inode_fsync_trans(handle, inode, 1);
4714 ret2 = ext4_journal_stop(handle);
4715 if (ret2)
4716 break;
4717 }
4718 if (ret == -ENOSPC &&
4719 ext4_should_retry_alloc(inode->i_sb, &retries)) {
4720 ret = 0;
4721 goto retry;
4722 }
4723
4724 return ret > 0 ? ret2 : ret;
4725}
4726
4727static long ext4_zero_range(struct file *file, loff_t offset,
4728 loff_t len, int mode)
4729{
4730 struct inode *inode = file_inode(file);
4731 handle_t *handle = NULL;
4732 unsigned int max_blocks;
4733 loff_t new_size = 0;
4734 int ret = 0;
4735 int flags;
4736 int credits;
4737 int partial_begin, partial_end;
4738 loff_t start, end;
4739 ext4_lblk_t lblk;
4740 unsigned int blkbits = inode->i_blkbits;
4741
4742 trace_ext4_zero_range(inode, offset, len, mode);
4743
4744 if (!S_ISREG(inode->i_mode))
4745 return -EINVAL;
4746
4747 /* Call ext4_force_commit to flush all data in case of data=journal. */
4748 if (ext4_should_journal_data(inode)) {
4749 ret = ext4_force_commit(inode->i_sb);
4750 if (ret)
4751 return ret;
4752 }
4753
4754 /*
4755 * Round up offset. This is not fallocate, we neet to zero out
4756 * blocks, so convert interior block aligned part of the range to
4757 * unwritten and possibly manually zero out unaligned parts of the
4758 * range.
4759 */
4760 start = round_up(offset, 1 << blkbits);
4761 end = round_down((offset + len), 1 << blkbits);
4762
4763 if (start < offset || end > offset + len)
4764 return -EINVAL;
4765 partial_begin = offset & ((1 << blkbits) - 1);
4766 partial_end = (offset + len) & ((1 << blkbits) - 1);
4767
4768 lblk = start >> blkbits;
4769 max_blocks = (end >> blkbits);
4770 if (max_blocks < lblk)
4771 max_blocks = 0;
4772 else
4773 max_blocks -= lblk;
4774
4775 inode_lock(inode);
4776
4777 /*
4778 * Indirect files do not support unwritten extnets
4779 */
4780 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4781 ret = -EOPNOTSUPP;
4782 goto out_mutex;
4783 }
4784
4785 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4786 (offset + len > i_size_read(inode) ||
4787 offset + len > EXT4_I(inode)->i_disksize)) {
4788 new_size = offset + len;
4789 ret = inode_newsize_ok(inode, new_size);
4790 if (ret)
4791 goto out_mutex;
4792 }
4793
4794 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4795 if (mode & FALLOC_FL_KEEP_SIZE)
4796 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4797
4798 /* Wait all existing dio workers, newcomers will block on i_mutex */
4799 inode_dio_wait(inode);
4800
4801 /* Preallocate the range including the unaligned edges */
4802 if (partial_begin || partial_end) {
4803 ret = ext4_alloc_file_blocks(file,
4804 round_down(offset, 1 << blkbits) >> blkbits,
4805 (round_up((offset + len), 1 << blkbits) -
4806 round_down(offset, 1 << blkbits)) >> blkbits,
4807 new_size, flags);
4808 if (ret)
4809 goto out_mutex;
4810
4811 }
4812
4813 /* Zero range excluding the unaligned edges */
4814 if (max_blocks > 0) {
4815 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4816 EXT4_EX_NOCACHE);
4817
4818 /*
4819 * Prevent page faults from reinstantiating pages we have
4820 * released from page cache.
4821 */
4822 down_write(&EXT4_I(inode)->i_mmap_sem);
4823 ret = ext4_update_disksize_before_punch(inode, offset, len);
4824 if (ret) {
4825 up_write(&EXT4_I(inode)->i_mmap_sem);
4826 goto out_mutex;
4827 }
4828 /* Now release the pages and zero block aligned part of pages */
4829 truncate_pagecache_range(inode, start, end - 1);
4830 inode->i_mtime = inode->i_ctime = current_time(inode);
4831
4832 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4833 flags);
4834 up_write(&EXT4_I(inode)->i_mmap_sem);
4835 if (ret)
4836 goto out_mutex;
4837 }
4838 if (!partial_begin && !partial_end)
4839 goto out_mutex;
4840
4841 /*
4842 * In worst case we have to writeout two nonadjacent unwritten
4843 * blocks and update the inode
4844 */
4845 credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4846 if (ext4_should_journal_data(inode))
4847 credits += 2;
4848 handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4849 if (IS_ERR(handle)) {
4850 ret = PTR_ERR(handle);
4851 ext4_std_error(inode->i_sb, ret);
4852 goto out_mutex;
4853 }
4854
4855 inode->i_mtime = inode->i_ctime = current_time(inode);
4856 if (new_size) {
4857 ext4_update_inode_size(inode, new_size);
4858 } else {
4859 /*
4860 * Mark that we allocate beyond EOF so the subsequent truncate
4861 * can proceed even if the new size is the same as i_size.
4862 */
4863 if ((offset + len) > i_size_read(inode))
4864 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4865 }
4866 ext4_mark_inode_dirty(handle, inode);
4867
4868 /* Zero out partial block at the edges of the range */
4869 ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4870 if (ret >= 0)
4871 ext4_update_inode_fsync_trans(handle, inode, 1);
4872
4873 if (file->f_flags & O_SYNC)
4874 ext4_handle_sync(handle);
4875
4876 ext4_journal_stop(handle);
4877out_mutex:
4878 inode_unlock(inode);
4879 return ret;
4880}
4881
4882/*
4883 * preallocate space for a file. This implements ext4's fallocate file
4884 * operation, which gets called from sys_fallocate system call.
4885 * For block-mapped files, posix_fallocate should fall back to the method
4886 * of writing zeroes to the required new blocks (the same behavior which is
4887 * expected for file systems which do not support fallocate() system call).
4888 */
4889long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4890{
4891 struct inode *inode = file_inode(file);
4892 loff_t new_size = 0;
4893 unsigned int max_blocks;
4894 int ret = 0;
4895 int flags;
4896 ext4_lblk_t lblk;
4897 unsigned int blkbits = inode->i_blkbits;
4898
4899 /*
4900 * Encrypted inodes can't handle collapse range or insert
4901 * range since we would need to re-encrypt blocks with a
4902 * different IV or XTS tweak (which are based on the logical
4903 * block number).
4904 *
4905 * XXX It's not clear why zero range isn't working, but we'll
4906 * leave it disabled for encrypted inodes for now. This is a
4907 * bug we should fix....
4908 */
4909 if (ext4_encrypted_inode(inode) &&
4910 (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4911 FALLOC_FL_ZERO_RANGE)))
4912 return -EOPNOTSUPP;
4913
4914 /* Return error if mode is not supported */
4915 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4916 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4917 FALLOC_FL_INSERT_RANGE))
4918 return -EOPNOTSUPP;
4919
4920 if (mode & FALLOC_FL_PUNCH_HOLE)
4921 return ext4_punch_hole(inode, offset, len);
4922
4923 ret = ext4_convert_inline_data(inode);
4924 if (ret)
4925 return ret;
4926
4927 if (mode & FALLOC_FL_COLLAPSE_RANGE)
4928 return ext4_collapse_range(inode, offset, len);
4929
4930 if (mode & FALLOC_FL_INSERT_RANGE)
4931 return ext4_insert_range(inode, offset, len);
4932
4933 if (mode & FALLOC_FL_ZERO_RANGE)
4934 return ext4_zero_range(file, offset, len, mode);
4935
4936 trace_ext4_fallocate_enter(inode, offset, len, mode);
4937 lblk = offset >> blkbits;
4938
4939 max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4940 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4941 if (mode & FALLOC_FL_KEEP_SIZE)
4942 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4943
4944 inode_lock(inode);
4945
4946 /*
4947 * We only support preallocation for extent-based files only
4948 */
4949 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4950 ret = -EOPNOTSUPP;
4951 goto out;
4952 }
4953
4954 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4955 (offset + len > i_size_read(inode) ||
4956 offset + len > EXT4_I(inode)->i_disksize)) {
4957 new_size = offset + len;
4958 ret = inode_newsize_ok(inode, new_size);
4959 if (ret)
4960 goto out;
4961 }
4962
4963 /* Wait all existing dio workers, newcomers will block on i_mutex */
4964 inode_dio_wait(inode);
4965
4966 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4967 if (ret)
4968 goto out;
4969
4970 if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4971 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4972 EXT4_I(inode)->i_sync_tid);
4973 }
4974out:
4975 inode_unlock(inode);
4976 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4977 return ret;
4978}
4979
4980/*
4981 * This function convert a range of blocks to written extents
4982 * The caller of this function will pass the start offset and the size.
4983 * all unwritten extents within this range will be converted to
4984 * written extents.
4985 *
4986 * This function is called from the direct IO end io call back
4987 * function, to convert the fallocated extents after IO is completed.
4988 * Returns 0 on success.
4989 */
4990int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4991 loff_t offset, ssize_t len)
4992{
4993 unsigned int max_blocks;
4994 int ret = 0;
4995 int ret2 = 0;
4996 struct ext4_map_blocks map;
4997 unsigned int credits, blkbits = inode->i_blkbits;
4998
4999 map.m_lblk = offset >> blkbits;
5000 max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
5001
5002 /*
5003 * This is somewhat ugly but the idea is clear: When transaction is
5004 * reserved, everything goes into it. Otherwise we rather start several
5005 * smaller transactions for conversion of each extent separately.
5006 */
5007 if (handle) {
5008 handle = ext4_journal_start_reserved(handle,
5009 EXT4_HT_EXT_CONVERT);
5010 if (IS_ERR(handle))
5011 return PTR_ERR(handle);
5012 credits = 0;
5013 } else {
5014 /*
5015 * credits to insert 1 extent into extent tree
5016 */
5017 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5018 }
5019 while (ret >= 0 && ret < max_blocks) {
5020 map.m_lblk += ret;
5021 map.m_len = (max_blocks -= ret);
5022 if (credits) {
5023 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5024 credits);
5025 if (IS_ERR(handle)) {
5026 ret = PTR_ERR(handle);
5027 break;
5028 }
5029 }
5030 ret = ext4_map_blocks(handle, inode, &map,
5031 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5032 if (ret <= 0)
5033 ext4_warning(inode->i_sb,
5034 "inode #%lu: block %u: len %u: "
5035 "ext4_ext_map_blocks returned %d",
5036 inode->i_ino, map.m_lblk,
5037 map.m_len, ret);
5038 ext4_mark_inode_dirty(handle, inode);
5039 if (credits)
5040 ret2 = ext4_journal_stop(handle);
5041 if (ret <= 0 || ret2)
5042 break;
5043 }
5044 if (!credits)
5045 ret2 = ext4_journal_stop(handle);
5046 return ret > 0 ? ret2 : ret;
5047}
5048
5049/*
5050 * If newes is not existing extent (newes->ec_pblk equals zero) find
5051 * delayed extent at start of newes and update newes accordingly and
5052 * return start of the next delayed extent.
5053 *
5054 * If newes is existing extent (newes->ec_pblk is not equal zero)
5055 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5056 * extent found. Leave newes unmodified.
5057 */
5058static int ext4_find_delayed_extent(struct inode *inode,
5059 struct extent_status *newes)
5060{
5061 struct extent_status es;
5062 ext4_lblk_t block, next_del;
5063
5064 if (newes->es_pblk == 0) {
5065 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5066 newes->es_lblk + newes->es_len - 1, &es);
5067
5068 /*
5069 * No extent in extent-tree contains block @newes->es_pblk,
5070 * then the block may stay in 1)a hole or 2)delayed-extent.
5071 */
5072 if (es.es_len == 0)
5073 /* A hole found. */
5074 return 0;
5075
5076 if (es.es_lblk > newes->es_lblk) {
5077 /* A hole found. */
5078 newes->es_len = min(es.es_lblk - newes->es_lblk,
5079 newes->es_len);
5080 return 0;
5081 }
5082
5083 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5084 }
5085
5086 block = newes->es_lblk + newes->es_len;
5087 ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5088 if (es.es_len == 0)
5089 next_del = EXT_MAX_BLOCKS;
5090 else
5091 next_del = es.es_lblk;
5092
5093 return next_del;
5094}
5095/* fiemap flags we can handle specified here */
5096#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5097
5098static int ext4_xattr_fiemap(struct inode *inode,
5099 struct fiemap_extent_info *fieinfo)
5100{
5101 __u64 physical = 0;
5102 __u64 length;
5103 __u32 flags = FIEMAP_EXTENT_LAST;
5104 int blockbits = inode->i_sb->s_blocksize_bits;
5105 int error = 0;
5106
5107 /* in-inode? */
5108 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5109 struct ext4_iloc iloc;
5110 int offset; /* offset of xattr in inode */
5111
5112 error = ext4_get_inode_loc(inode, &iloc);
5113 if (error)
5114 return error;
5115 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5116 offset = EXT4_GOOD_OLD_INODE_SIZE +
5117 EXT4_I(inode)->i_extra_isize;
5118 physical += offset;
5119 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5120 flags |= FIEMAP_EXTENT_DATA_INLINE;
5121 brelse(iloc.bh);
5122 } else { /* external block */
5123 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5124 length = inode->i_sb->s_blocksize;
5125 }
5126
5127 if (physical)
5128 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5129 length, flags);
5130 return (error < 0 ? error : 0);
5131}
5132
5133int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5134 __u64 start, __u64 len)
5135{
5136 ext4_lblk_t start_blk;
5137 int error = 0;
5138
5139 if (ext4_has_inline_data(inode)) {
5140 int has_inline = 1;
5141
5142 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5143 start, len);
5144
5145 if (has_inline)
5146 return error;
5147 }
5148
5149 if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5150 error = ext4_ext_precache(inode);
5151 if (error)
5152 return error;
5153 }
5154
5155 /* fallback to generic here if not in extents fmt */
5156 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5157 return generic_block_fiemap(inode, fieinfo, start, len,
5158 ext4_get_block);
5159
5160 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5161 return -EBADR;
5162
5163 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5164 error = ext4_xattr_fiemap(inode, fieinfo);
5165 } else {
5166 ext4_lblk_t len_blks;
5167 __u64 last_blk;
5168
5169 start_blk = start >> inode->i_sb->s_blocksize_bits;
5170 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5171 if (last_blk >= EXT_MAX_BLOCKS)
5172 last_blk = EXT_MAX_BLOCKS-1;
5173 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5174
5175 /*
5176 * Walk the extent tree gathering extent information
5177 * and pushing extents back to the user.
5178 */
5179 error = ext4_fill_fiemap_extents(inode, start_blk,
5180 len_blks, fieinfo);
5181 }
5182 return error;
5183}
5184
5185/*
5186 * ext4_access_path:
5187 * Function to access the path buffer for marking it dirty.
5188 * It also checks if there are sufficient credits left in the journal handle
5189 * to update path.
5190 */
5191static int
5192ext4_access_path(handle_t *handle, struct inode *inode,
5193 struct ext4_ext_path *path)
5194{
5195 int credits, err;
5196
5197 if (!ext4_handle_valid(handle))
5198 return 0;
5199
5200 /*
5201 * Check if need to extend journal credits
5202 * 3 for leaf, sb, and inode plus 2 (bmap and group
5203 * descriptor) for each block group; assume two block
5204 * groups
5205 */
5206 if (handle->h_buffer_credits < 7) {
5207 credits = ext4_writepage_trans_blocks(inode);
5208 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5209 /* EAGAIN is success */
5210 if (err && err != -EAGAIN)
5211 return err;
5212 }
5213
5214 err = ext4_ext_get_access(handle, inode, path);
5215 return err;
5216}
5217
5218/*
5219 * ext4_ext_shift_path_extents:
5220 * Shift the extents of a path structure lying between path[depth].p_ext
5221 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5222 * if it is right shift or left shift operation.
5223 */
5224static int
5225ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5226 struct inode *inode, handle_t *handle,
5227 enum SHIFT_DIRECTION SHIFT)
5228{
5229 int depth, err = 0;
5230 struct ext4_extent *ex_start, *ex_last;
5231 bool update = 0;
5232 depth = path->p_depth;
5233
5234 while (depth >= 0) {
5235 if (depth == path->p_depth) {
5236 ex_start = path[depth].p_ext;
5237 if (!ex_start)
5238 return -EFSCORRUPTED;
5239
5240 ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5241
5242 err = ext4_access_path(handle, inode, path + depth);
5243 if (err)
5244 goto out;
5245
5246 if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5247 update = 1;
5248
5249 while (ex_start <= ex_last) {
5250 if (SHIFT == SHIFT_LEFT) {
5251 le32_add_cpu(&ex_start->ee_block,
5252 -shift);
5253 /* Try to merge to the left. */
5254 if ((ex_start >
5255 EXT_FIRST_EXTENT(path[depth].p_hdr))
5256 &&
5257 ext4_ext_try_to_merge_right(inode,
5258 path, ex_start - 1))
5259 ex_last--;
5260 else
5261 ex_start++;
5262 } else {
5263 le32_add_cpu(&ex_last->ee_block, shift);
5264 ext4_ext_try_to_merge_right(inode, path,
5265 ex_last);
5266 ex_last--;
5267 }
5268 }
5269 err = ext4_ext_dirty(handle, inode, path + depth);
5270 if (err)
5271 goto out;
5272
5273 if (--depth < 0 || !update)
5274 break;
5275 }
5276
5277 /* Update index too */
5278 err = ext4_access_path(handle, inode, path + depth);
5279 if (err)
5280 goto out;
5281
5282 if (SHIFT == SHIFT_LEFT)
5283 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5284 else
5285 le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5286 err = ext4_ext_dirty(handle, inode, path + depth);
5287 if (err)
5288 goto out;
5289
5290 /* we are done if current index is not a starting index */
5291 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5292 break;
5293
5294 depth--;
5295 }
5296
5297out:
5298 return err;
5299}
5300
5301/*
5302 * ext4_ext_shift_extents:
5303 * All the extents which lies in the range from @start to the last allocated
5304 * block for the @inode are shifted either towards left or right (depending
5305 * upon @SHIFT) by @shift blocks.
5306 * On success, 0 is returned, error otherwise.
5307 */
5308static int
5309ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5310 ext4_lblk_t start, ext4_lblk_t shift,
5311 enum SHIFT_DIRECTION SHIFT)
5312{
5313 struct ext4_ext_path *path;
5314 int ret = 0, depth;
5315 struct ext4_extent *extent;
5316 ext4_lblk_t stop, *iterator, ex_start, ex_end;
5317
5318 /* Let path point to the last extent */
5319 path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5320 EXT4_EX_NOCACHE);
5321 if (IS_ERR(path))
5322 return PTR_ERR(path);
5323
5324 depth = path->p_depth;
5325 extent = path[depth].p_ext;
5326 if (!extent)
5327 goto out;
5328
5329 stop = le32_to_cpu(extent->ee_block);
5330
5331 /*
5332 * For left shifts, make sure the hole on the left is big enough to
5333 * accommodate the shift. For right shifts, make sure the last extent
5334 * won't be shifted beyond EXT_MAX_BLOCKS.
5335 */
5336 if (SHIFT == SHIFT_LEFT) {
5337 path = ext4_find_extent(inode, start - 1, &path,
5338 EXT4_EX_NOCACHE);
5339 if (IS_ERR(path))
5340 return PTR_ERR(path);
5341 depth = path->p_depth;
5342 extent = path[depth].p_ext;
5343 if (extent) {
5344 ex_start = le32_to_cpu(extent->ee_block);
5345 ex_end = le32_to_cpu(extent->ee_block) +
5346 ext4_ext_get_actual_len(extent);
5347 } else {
5348 ex_start = 0;
5349 ex_end = 0;
5350 }
5351
5352 if ((start == ex_start && shift > ex_start) ||
5353 (shift > start - ex_end)) {
5354 ret = -EINVAL;
5355 goto out;
5356 }
5357 } else {
5358 if (shift > EXT_MAX_BLOCKS -
5359 (stop + ext4_ext_get_actual_len(extent))) {
5360 ret = -EINVAL;
5361 goto out;
5362 }
5363 }
5364
5365 /*
5366 * In case of left shift, iterator points to start and it is increased
5367 * till we reach stop. In case of right shift, iterator points to stop
5368 * and it is decreased till we reach start.
5369 */
5370 if (SHIFT == SHIFT_LEFT)
5371 iterator = &start;
5372 else
5373 iterator = &stop;
5374
5375 /*
5376 * Its safe to start updating extents. Start and stop are unsigned, so
5377 * in case of right shift if extent with 0 block is reached, iterator
5378 * becomes NULL to indicate the end of the loop.
5379 */
5380 while (iterator && start <= stop) {
5381 path = ext4_find_extent(inode, *iterator, &path,
5382 EXT4_EX_NOCACHE);
5383 if (IS_ERR(path))
5384 return PTR_ERR(path);
5385 depth = path->p_depth;
5386 extent = path[depth].p_ext;
5387 if (!extent) {
5388 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5389 (unsigned long) *iterator);
5390 return -EFSCORRUPTED;
5391 }
5392 if (SHIFT == SHIFT_LEFT && *iterator >
5393 le32_to_cpu(extent->ee_block)) {
5394 /* Hole, move to the next extent */
5395 if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5396 path[depth].p_ext++;
5397 } else {
5398 *iterator = ext4_ext_next_allocated_block(path);
5399 continue;
5400 }
5401 }
5402
5403 if (SHIFT == SHIFT_LEFT) {
5404 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5405 *iterator = le32_to_cpu(extent->ee_block) +
5406 ext4_ext_get_actual_len(extent);
5407 } else {
5408 extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5409 if (le32_to_cpu(extent->ee_block) > 0)
5410 *iterator = le32_to_cpu(extent->ee_block) - 1;
5411 else
5412 /* Beginning is reached, end of the loop */
5413 iterator = NULL;
5414 /* Update path extent in case we need to stop */
5415 while (le32_to_cpu(extent->ee_block) < start)
5416 extent++;
5417 path[depth].p_ext = extent;
5418 }
5419 ret = ext4_ext_shift_path_extents(path, shift, inode,
5420 handle, SHIFT);
5421 if (ret)
5422 break;
5423 }
5424out:
5425 ext4_ext_drop_refs(path);
5426 kfree(path);
5427 return ret;
5428}
5429
5430/*
5431 * ext4_collapse_range:
5432 * This implements the fallocate's collapse range functionality for ext4
5433 * Returns: 0 and non-zero on error.
5434 */
5435int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5436{
5437 struct super_block *sb = inode->i_sb;
5438 ext4_lblk_t punch_start, punch_stop;
5439 handle_t *handle;
5440 unsigned int credits;
5441 loff_t new_size, ioffset;
5442 int ret;
5443
5444 /*
5445 * We need to test this early because xfstests assumes that a
5446 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5447 * system does not support collapse range.
5448 */
5449 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5450 return -EOPNOTSUPP;
5451
5452 /* Collapse range works only on fs block size aligned offsets. */
5453 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5454 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5455 return -EINVAL;
5456
5457 if (!S_ISREG(inode->i_mode))
5458 return -EINVAL;
5459
5460 trace_ext4_collapse_range(inode, offset, len);
5461
5462 punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5463 punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5464
5465 /* Call ext4_force_commit to flush all data in case of data=journal. */
5466 if (ext4_should_journal_data(inode)) {
5467 ret = ext4_force_commit(inode->i_sb);
5468 if (ret)
5469 return ret;
5470 }
5471
5472 inode_lock(inode);
5473 /*
5474 * There is no need to overlap collapse range with EOF, in which case
5475 * it is effectively a truncate operation
5476 */
5477 if (offset + len >= i_size_read(inode)) {
5478 ret = -EINVAL;
5479 goto out_mutex;
5480 }
5481
5482 /* Currently just for extent based files */
5483 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5484 ret = -EOPNOTSUPP;
5485 goto out_mutex;
5486 }
5487
5488 /* Wait for existing dio to complete */
5489 inode_dio_wait(inode);
5490
5491 /*
5492 * Prevent page faults from reinstantiating pages we have released from
5493 * page cache.
5494 */
5495 down_write(&EXT4_I(inode)->i_mmap_sem);
5496 /*
5497 * Need to round down offset to be aligned with page size boundary
5498 * for page size > block size.
5499 */
5500 ioffset = round_down(offset, PAGE_SIZE);
5501 /*
5502 * Write tail of the last page before removed range since it will get
5503 * removed from the page cache below.
5504 */
5505 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5506 if (ret)
5507 goto out_mmap;
5508 /*
5509 * Write data that will be shifted to preserve them when discarding
5510 * page cache below. We are also protected from pages becoming dirty
5511 * by i_mmap_sem.
5512 */
5513 ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5514 LLONG_MAX);
5515 if (ret)
5516 goto out_mmap;
5517 truncate_pagecache(inode, ioffset);
5518
5519 credits = ext4_writepage_trans_blocks(inode);
5520 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5521 if (IS_ERR(handle)) {
5522 ret = PTR_ERR(handle);
5523 goto out_mmap;
5524 }
5525
5526 down_write(&EXT4_I(inode)->i_data_sem);
5527 ext4_discard_preallocations(inode);
5528
5529 ret = ext4_es_remove_extent(inode, punch_start,
5530 EXT_MAX_BLOCKS - punch_start);
5531 if (ret) {
5532 up_write(&EXT4_I(inode)->i_data_sem);
5533 goto out_stop;
5534 }
5535
5536 ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5537 if (ret) {
5538 up_write(&EXT4_I(inode)->i_data_sem);
5539 goto out_stop;
5540 }
5541 ext4_discard_preallocations(inode);
5542
5543 ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5544 punch_stop - punch_start, SHIFT_LEFT);
5545 if (ret) {
5546 up_write(&EXT4_I(inode)->i_data_sem);
5547 goto out_stop;
5548 }
5549
5550 new_size = i_size_read(inode) - len;
5551 i_size_write(inode, new_size);
5552 EXT4_I(inode)->i_disksize = new_size;
5553
5554 up_write(&EXT4_I(inode)->i_data_sem);
5555 if (IS_SYNC(inode))
5556 ext4_handle_sync(handle);
5557 inode->i_mtime = inode->i_ctime = current_time(inode);
5558 ext4_mark_inode_dirty(handle, inode);
5559 ext4_update_inode_fsync_trans(handle, inode, 1);
5560
5561out_stop:
5562 ext4_journal_stop(handle);
5563out_mmap:
5564 up_write(&EXT4_I(inode)->i_mmap_sem);
5565out_mutex:
5566 inode_unlock(inode);
5567 return ret;
5568}
5569
5570/*
5571 * ext4_insert_range:
5572 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5573 * The data blocks starting from @offset to the EOF are shifted by @len
5574 * towards right to create a hole in the @inode. Inode size is increased
5575 * by len bytes.
5576 * Returns 0 on success, error otherwise.
5577 */
5578int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5579{
5580 struct super_block *sb = inode->i_sb;
5581 handle_t *handle;
5582 struct ext4_ext_path *path;
5583 struct ext4_extent *extent;
5584 ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5585 unsigned int credits, ee_len;
5586 int ret = 0, depth, split_flag = 0;
5587 loff_t ioffset;
5588
5589 /*
5590 * We need to test this early because xfstests assumes that an
5591 * insert range of (0, 1) will return EOPNOTSUPP if the file
5592 * system does not support insert range.
5593 */
5594 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5595 return -EOPNOTSUPP;
5596
5597 /* Insert range works only on fs block size aligned offsets. */
5598 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5599 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5600 return -EINVAL;
5601
5602 if (!S_ISREG(inode->i_mode))
5603 return -EOPNOTSUPP;
5604
5605 trace_ext4_insert_range(inode, offset, len);
5606
5607 offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5608 len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5609
5610 /* Call ext4_force_commit to flush all data in case of data=journal */
5611 if (ext4_should_journal_data(inode)) {
5612 ret = ext4_force_commit(inode->i_sb);
5613 if (ret)
5614 return ret;
5615 }
5616
5617 inode_lock(inode);
5618 /* Currently just for extent based files */
5619 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5620 ret = -EOPNOTSUPP;
5621 goto out_mutex;
5622 }
5623
5624 /* Check for wrap through zero */
5625 if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5626 ret = -EFBIG;
5627 goto out_mutex;
5628 }
5629
5630 /* Offset should be less than i_size */
5631 if (offset >= i_size_read(inode)) {
5632 ret = -EINVAL;
5633 goto out_mutex;
5634 }
5635
5636 /* Wait for existing dio to complete */
5637 inode_dio_wait(inode);
5638
5639 /*
5640 * Prevent page faults from reinstantiating pages we have released from
5641 * page cache.
5642 */
5643 down_write(&EXT4_I(inode)->i_mmap_sem);
5644 /*
5645 * Need to round down to align start offset to page size boundary
5646 * for page size > block size.
5647 */
5648 ioffset = round_down(offset, PAGE_SIZE);
5649 /* Write out all dirty pages */
5650 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5651 LLONG_MAX);
5652 if (ret)
5653 goto out_mmap;
5654 truncate_pagecache(inode, ioffset);
5655
5656 credits = ext4_writepage_trans_blocks(inode);
5657 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5658 if (IS_ERR(handle)) {
5659 ret = PTR_ERR(handle);
5660 goto out_mmap;
5661 }
5662
5663 /* Expand file to avoid data loss if there is error while shifting */
5664 inode->i_size += len;
5665 EXT4_I(inode)->i_disksize += len;
5666 inode->i_mtime = inode->i_ctime = current_time(inode);
5667 ret = ext4_mark_inode_dirty(handle, inode);
5668 if (ret)
5669 goto out_stop;
5670
5671 down_write(&EXT4_I(inode)->i_data_sem);
5672 ext4_discard_preallocations(inode);
5673
5674 path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5675 if (IS_ERR(path)) {
5676 up_write(&EXT4_I(inode)->i_data_sem);
5677 goto out_stop;
5678 }
5679
5680 depth = ext_depth(inode);
5681 extent = path[depth].p_ext;
5682 if (extent) {
5683 ee_start_lblk = le32_to_cpu(extent->ee_block);
5684 ee_len = ext4_ext_get_actual_len(extent);
5685
5686 /*
5687 * If offset_lblk is not the starting block of extent, split
5688 * the extent @offset_lblk
5689 */
5690 if ((offset_lblk > ee_start_lblk) &&
5691 (offset_lblk < (ee_start_lblk + ee_len))) {
5692 if (ext4_ext_is_unwritten(extent))
5693 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5694 EXT4_EXT_MARK_UNWRIT2;
5695 ret = ext4_split_extent_at(handle, inode, &path,
5696 offset_lblk, split_flag,
5697 EXT4_EX_NOCACHE |
5698 EXT4_GET_BLOCKS_PRE_IO |
5699 EXT4_GET_BLOCKS_METADATA_NOFAIL);
5700 }
5701
5702 ext4_ext_drop_refs(path);
5703 kfree(path);
5704 if (ret < 0) {
5705 up_write(&EXT4_I(inode)->i_data_sem);
5706 goto out_stop;
5707 }
5708 } else {
5709 ext4_ext_drop_refs(path);
5710 kfree(path);
5711 }
5712
5713 ret = ext4_es_remove_extent(inode, offset_lblk,
5714 EXT_MAX_BLOCKS - offset_lblk);
5715 if (ret) {
5716 up_write(&EXT4_I(inode)->i_data_sem);
5717 goto out_stop;
5718 }
5719
5720 /*
5721 * if offset_lblk lies in a hole which is at start of file, use
5722 * ee_start_lblk to shift extents
5723 */
5724 ret = ext4_ext_shift_extents(inode, handle,
5725 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5726 len_lblk, SHIFT_RIGHT);
5727
5728 up_write(&EXT4_I(inode)->i_data_sem);
5729 if (IS_SYNC(inode))
5730 ext4_handle_sync(handle);
5731 if (ret >= 0)
5732 ext4_update_inode_fsync_trans(handle, inode, 1);
5733
5734out_stop:
5735 ext4_journal_stop(handle);
5736out_mmap:
5737 up_write(&EXT4_I(inode)->i_mmap_sem);
5738out_mutex:
5739 inode_unlock(inode);
5740 return ret;
5741}
5742
5743/**
5744 * ext4_swap_extents - Swap extents between two inodes
5745 *
5746 * @inode1: First inode
5747 * @inode2: Second inode
5748 * @lblk1: Start block for first inode
5749 * @lblk2: Start block for second inode
5750 * @count: Number of blocks to swap
5751 * @unwritten: Mark second inode's extents as unwritten after swap
5752 * @erp: Pointer to save error value
5753 *
5754 * This helper routine does exactly what is promise "swap extents". All other
5755 * stuff such as page-cache locking consistency, bh mapping consistency or
5756 * extent's data copying must be performed by caller.
5757 * Locking:
5758 * i_mutex is held for both inodes
5759 * i_data_sem is locked for write for both inodes
5760 * Assumptions:
5761 * All pages from requested range are locked for both inodes
5762 */
5763int
5764ext4_swap_extents(handle_t *handle, struct inode *inode1,
5765 struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5766 ext4_lblk_t count, int unwritten, int *erp)
5767{
5768 struct ext4_ext_path *path1 = NULL;
5769 struct ext4_ext_path *path2 = NULL;
5770 int replaced_count = 0;
5771
5772 BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5773 BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5774 BUG_ON(!inode_is_locked(inode1));
5775 BUG_ON(!inode_is_locked(inode2));
5776
5777 *erp = ext4_es_remove_extent(inode1, lblk1, count);
5778 if (unlikely(*erp))
5779 return 0;
5780 *erp = ext4_es_remove_extent(inode2, lblk2, count);
5781 if (unlikely(*erp))
5782 return 0;
5783
5784 while (count) {
5785 struct ext4_extent *ex1, *ex2, tmp_ex;
5786 ext4_lblk_t e1_blk, e2_blk;
5787 int e1_len, e2_len, len;
5788 int split = 0;
5789
5790 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5791 if (IS_ERR(path1)) {
5792 *erp = PTR_ERR(path1);
5793 path1 = NULL;
5794 finish:
5795 count = 0;
5796 goto repeat;
5797 }
5798 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5799 if (IS_ERR(path2)) {
5800 *erp = PTR_ERR(path2);
5801 path2 = NULL;
5802 goto finish;
5803 }
5804 ex1 = path1[path1->p_depth].p_ext;
5805 ex2 = path2[path2->p_depth].p_ext;
5806 /* Do we have somthing to swap ? */
5807 if (unlikely(!ex2 || !ex1))
5808 goto finish;
5809
5810 e1_blk = le32_to_cpu(ex1->ee_block);
5811 e2_blk = le32_to_cpu(ex2->ee_block);
5812 e1_len = ext4_ext_get_actual_len(ex1);
5813 e2_len = ext4_ext_get_actual_len(ex2);
5814
5815 /* Hole handling */
5816 if (!in_range(lblk1, e1_blk, e1_len) ||
5817 !in_range(lblk2, e2_blk, e2_len)) {
5818 ext4_lblk_t next1, next2;
5819
5820 /* if hole after extent, then go to next extent */
5821 next1 = ext4_ext_next_allocated_block(path1);
5822 next2 = ext4_ext_next_allocated_block(path2);
5823 /* If hole before extent, then shift to that extent */
5824 if (e1_blk > lblk1)
5825 next1 = e1_blk;
5826 if (e2_blk > lblk2)
5827 next2 = e2_blk;
5828 /* Do we have something to swap */
5829 if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5830 goto finish;
5831 /* Move to the rightest boundary */
5832 len = next1 - lblk1;
5833 if (len < next2 - lblk2)
5834 len = next2 - lblk2;
5835 if (len > count)
5836 len = count;
5837 lblk1 += len;
5838 lblk2 += len;
5839 count -= len;
5840 goto repeat;
5841 }
5842
5843 /* Prepare left boundary */
5844 if (e1_blk < lblk1) {
5845 split = 1;
5846 *erp = ext4_force_split_extent_at(handle, inode1,
5847 &path1, lblk1, 0);
5848 if (unlikely(*erp))
5849 goto finish;
5850 }
5851 if (e2_blk < lblk2) {
5852 split = 1;
5853 *erp = ext4_force_split_extent_at(handle, inode2,
5854 &path2, lblk2, 0);
5855 if (unlikely(*erp))
5856 goto finish;
5857 }
5858 /* ext4_split_extent_at() may result in leaf extent split,
5859 * path must to be revalidated. */
5860 if (split)
5861 goto repeat;
5862
5863 /* Prepare right boundary */
5864 len = count;
5865 if (len > e1_blk + e1_len - lblk1)
5866 len = e1_blk + e1_len - lblk1;
5867 if (len > e2_blk + e2_len - lblk2)
5868 len = e2_blk + e2_len - lblk2;
5869
5870 if (len != e1_len) {
5871 split = 1;
5872 *erp = ext4_force_split_extent_at(handle, inode1,
5873 &path1, lblk1 + len, 0);
5874 if (unlikely(*erp))
5875 goto finish;
5876 }
5877 if (len != e2_len) {
5878 split = 1;
5879 *erp = ext4_force_split_extent_at(handle, inode2,
5880 &path2, lblk2 + len, 0);
5881 if (*erp)
5882 goto finish;
5883 }
5884 /* ext4_split_extent_at() may result in leaf extent split,
5885 * path must to be revalidated. */
5886 if (split)
5887 goto repeat;
5888
5889 BUG_ON(e2_len != e1_len);
5890 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5891 if (unlikely(*erp))
5892 goto finish;
5893 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5894 if (unlikely(*erp))
5895 goto finish;
5896
5897 /* Both extents are fully inside boundaries. Swap it now */
5898 tmp_ex = *ex1;
5899 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5900 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5901 ex1->ee_len = cpu_to_le16(e2_len);
5902 ex2->ee_len = cpu_to_le16(e1_len);
5903 if (unwritten)
5904 ext4_ext_mark_unwritten(ex2);
5905 if (ext4_ext_is_unwritten(&tmp_ex))
5906 ext4_ext_mark_unwritten(ex1);
5907
5908 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5909 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5910 *erp = ext4_ext_dirty(handle, inode2, path2 +
5911 path2->p_depth);
5912 if (unlikely(*erp))
5913 goto finish;
5914 *erp = ext4_ext_dirty(handle, inode1, path1 +
5915 path1->p_depth);
5916 /*
5917 * Looks scarry ah..? second inode already points to new blocks,
5918 * and it was successfully dirtied. But luckily error may happen
5919 * only due to journal error, so full transaction will be
5920 * aborted anyway.
5921 */
5922 if (unlikely(*erp))
5923 goto finish;
5924 lblk1 += len;
5925 lblk2 += len;
5926 replaced_count += len;
5927 count -= len;
5928
5929 repeat:
5930 ext4_ext_drop_refs(path1);
5931 kfree(path1);
5932 ext4_ext_drop_refs(path2);
5933 kfree(path2);
5934 path1 = path2 = NULL;
5935 }
5936 return replaced_count;
5937}