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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/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * Architecture independence:
6 * Copyright (c) 2005, Bull S.A.
7 * Written by Pierre Peiffer <pierre.peiffer@bull.net>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
21 */
22
23/*
24 * Extents support for EXT4
25 *
26 * TODO:
27 * - ext4*_error() should be used in some situations
28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
29 * - smart tree reduction
30 */
31
32#include <linux/fs.h>
33#include <linux/time.h>
34#include <linux/jbd2.h>
35#include <linux/highuid.h>
36#include <linux/pagemap.h>
37#include <linux/quotaops.h>
38#include <linux/string.h>
39#include <linux/slab.h>
40#include <asm/uaccess.h>
41#include <linux/fiemap.h>
42#include <linux/backing-dev.h>
43#include "ext4_jbd2.h"
44#include "ext4_extents.h"
45#include "xattr.h"
46
47#include <trace/events/ext4.h>
48
49/*
50 * used by extent splitting.
51 */
52#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
53 due to ENOSPC */
54#define EXT4_EXT_MARK_UNWRIT1 0x2 /* mark first half unwritten */
55#define EXT4_EXT_MARK_UNWRIT2 0x4 /* mark second half unwritten */
56
57#define EXT4_EXT_DATA_VALID1 0x8 /* first half contains valid data */
58#define EXT4_EXT_DATA_VALID2 0x10 /* second half contains valid data */
59
60static __le32 ext4_extent_block_csum(struct inode *inode,
61 struct ext4_extent_header *eh)
62{
63 struct ext4_inode_info *ei = EXT4_I(inode);
64 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
65 __u32 csum;
66
67 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
68 EXT4_EXTENT_TAIL_OFFSET(eh));
69 return cpu_to_le32(csum);
70}
71
72static int ext4_extent_block_csum_verify(struct inode *inode,
73 struct ext4_extent_header *eh)
74{
75 struct ext4_extent_tail *et;
76
77 if (!ext4_has_metadata_csum(inode->i_sb))
78 return 1;
79
80 et = find_ext4_extent_tail(eh);
81 if (et->et_checksum != ext4_extent_block_csum(inode, eh))
82 return 0;
83 return 1;
84}
85
86static void ext4_extent_block_csum_set(struct inode *inode,
87 struct ext4_extent_header *eh)
88{
89 struct ext4_extent_tail *et;
90
91 if (!ext4_has_metadata_csum(inode->i_sb))
92 return;
93
94 et = find_ext4_extent_tail(eh);
95 et->et_checksum = ext4_extent_block_csum(inode, eh);
96}
97
98static int ext4_split_extent(handle_t *handle,
99 struct inode *inode,
100 struct ext4_ext_path **ppath,
101 struct ext4_map_blocks *map,
102 int split_flag,
103 int flags);
104
105static int ext4_split_extent_at(handle_t *handle,
106 struct inode *inode,
107 struct ext4_ext_path **ppath,
108 ext4_lblk_t split,
109 int split_flag,
110 int flags);
111
112static int ext4_find_delayed_extent(struct inode *inode,
113 struct extent_status *newes);
114
115static int ext4_ext_truncate_extend_restart(handle_t *handle,
116 struct inode *inode,
117 int needed)
118{
119 int err;
120
121 if (!ext4_handle_valid(handle))
122 return 0;
123 if (handle->h_buffer_credits > needed)
124 return 0;
125 err = ext4_journal_extend(handle, needed);
126 if (err <= 0)
127 return err;
128 err = ext4_truncate_restart_trans(handle, inode, needed);
129 if (err == 0)
130 err = -EAGAIN;
131
132 return err;
133}
134
135/*
136 * could return:
137 * - EROFS
138 * - ENOMEM
139 */
140static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
141 struct ext4_ext_path *path)
142{
143 if (path->p_bh) {
144 /* path points to block */
145 BUFFER_TRACE(path->p_bh, "get_write_access");
146 return ext4_journal_get_write_access(handle, path->p_bh);
147 }
148 /* path points to leaf/index in inode body */
149 /* we use in-core data, no need to protect them */
150 return 0;
151}
152
153/*
154 * could return:
155 * - EROFS
156 * - ENOMEM
157 * - EIO
158 */
159int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
160 struct inode *inode, struct ext4_ext_path *path)
161{
162 int err;
163
164 WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
165 if (path->p_bh) {
166 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
167 /* path points to block */
168 err = __ext4_handle_dirty_metadata(where, line, handle,
169 inode, path->p_bh);
170 } else {
171 /* path points to leaf/index in inode body */
172 err = ext4_mark_inode_dirty(handle, inode);
173 }
174 return err;
175}
176
177static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
178 struct ext4_ext_path *path,
179 ext4_lblk_t block)
180{
181 if (path) {
182 int depth = path->p_depth;
183 struct ext4_extent *ex;
184
185 /*
186 * Try to predict block placement assuming that we are
187 * filling in a file which will eventually be
188 * non-sparse --- i.e., in the case of libbfd writing
189 * an ELF object sections out-of-order but in a way
190 * the eventually results in a contiguous object or
191 * executable file, or some database extending a table
192 * space file. However, this is actually somewhat
193 * non-ideal if we are writing a sparse file such as
194 * qemu or KVM writing a raw image file that is going
195 * to stay fairly sparse, since it will end up
196 * fragmenting the file system's free space. Maybe we
197 * should have some hueristics or some way to allow
198 * userspace to pass a hint to file system,
199 * especially if the latter case turns out to be
200 * common.
201 */
202 ex = path[depth].p_ext;
203 if (ex) {
204 ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
205 ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
206
207 if (block > ext_block)
208 return ext_pblk + (block - ext_block);
209 else
210 return ext_pblk - (ext_block - block);
211 }
212
213 /* it looks like index is empty;
214 * try to find starting block from index itself */
215 if (path[depth].p_bh)
216 return path[depth].p_bh->b_blocknr;
217 }
218
219 /* OK. use inode's group */
220 return ext4_inode_to_goal_block(inode);
221}
222
223/*
224 * Allocation for a meta data block
225 */
226static ext4_fsblk_t
227ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
228 struct ext4_ext_path *path,
229 struct ext4_extent *ex, int *err, unsigned int flags)
230{
231 ext4_fsblk_t goal, newblock;
232
233 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
234 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
235 NULL, err);
236 return newblock;
237}
238
239static inline int ext4_ext_space_block(struct inode *inode, int check)
240{
241 int size;
242
243 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
244 / sizeof(struct ext4_extent);
245#ifdef AGGRESSIVE_TEST
246 if (!check && size > 6)
247 size = 6;
248#endif
249 return size;
250}
251
252static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
253{
254 int size;
255
256 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
257 / sizeof(struct ext4_extent_idx);
258#ifdef AGGRESSIVE_TEST
259 if (!check && size > 5)
260 size = 5;
261#endif
262 return size;
263}
264
265static inline int ext4_ext_space_root(struct inode *inode, int check)
266{
267 int size;
268
269 size = sizeof(EXT4_I(inode)->i_data);
270 size -= sizeof(struct ext4_extent_header);
271 size /= sizeof(struct ext4_extent);
272#ifdef AGGRESSIVE_TEST
273 if (!check && size > 3)
274 size = 3;
275#endif
276 return size;
277}
278
279static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
280{
281 int size;
282
283 size = sizeof(EXT4_I(inode)->i_data);
284 size -= sizeof(struct ext4_extent_header);
285 size /= sizeof(struct ext4_extent_idx);
286#ifdef AGGRESSIVE_TEST
287 if (!check && size > 4)
288 size = 4;
289#endif
290 return size;
291}
292
293static inline int
294ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
295 struct ext4_ext_path **ppath, ext4_lblk_t lblk,
296 int nofail)
297{
298 struct ext4_ext_path *path = *ppath;
299 int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
300
301 return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
302 EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
303 EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
304 (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
305}
306
307/*
308 * Calculate the number of metadata blocks needed
309 * to allocate @blocks
310 * Worse case is one block per extent
311 */
312int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
313{
314 struct ext4_inode_info *ei = EXT4_I(inode);
315 int idxs;
316
317 idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
318 / sizeof(struct ext4_extent_idx));
319
320 /*
321 * If the new delayed allocation block is contiguous with the
322 * previous da block, it can share index blocks with the
323 * previous block, so we only need to allocate a new index
324 * block every idxs leaf blocks. At ldxs**2 blocks, we need
325 * an additional index block, and at ldxs**3 blocks, yet
326 * another index blocks.
327 */
328 if (ei->i_da_metadata_calc_len &&
329 ei->i_da_metadata_calc_last_lblock+1 == lblock) {
330 int num = 0;
331
332 if ((ei->i_da_metadata_calc_len % idxs) == 0)
333 num++;
334 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
335 num++;
336 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
337 num++;
338 ei->i_da_metadata_calc_len = 0;
339 } else
340 ei->i_da_metadata_calc_len++;
341 ei->i_da_metadata_calc_last_lblock++;
342 return num;
343 }
344
345 /*
346 * In the worst case we need a new set of index blocks at
347 * every level of the inode's extent tree.
348 */
349 ei->i_da_metadata_calc_len = 1;
350 ei->i_da_metadata_calc_last_lblock = lblock;
351 return ext_depth(inode) + 1;
352}
353
354static int
355ext4_ext_max_entries(struct inode *inode, int depth)
356{
357 int max;
358
359 if (depth == ext_depth(inode)) {
360 if (depth == 0)
361 max = ext4_ext_space_root(inode, 1);
362 else
363 max = ext4_ext_space_root_idx(inode, 1);
364 } else {
365 if (depth == 0)
366 max = ext4_ext_space_block(inode, 1);
367 else
368 max = ext4_ext_space_block_idx(inode, 1);
369 }
370
371 return max;
372}
373
374static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
375{
376 ext4_fsblk_t block = ext4_ext_pblock(ext);
377 int len = ext4_ext_get_actual_len(ext);
378 ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
379 ext4_lblk_t last = lblock + len - 1;
380
381 if (len == 0 || lblock > last)
382 return 0;
383 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
384}
385
386static int ext4_valid_extent_idx(struct inode *inode,
387 struct ext4_extent_idx *ext_idx)
388{
389 ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
390
391 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
392}
393
394static int ext4_valid_extent_entries(struct inode *inode,
395 struct ext4_extent_header *eh,
396 int depth)
397{
398 unsigned short entries;
399 if (eh->eh_entries == 0)
400 return 1;
401
402 entries = le16_to_cpu(eh->eh_entries);
403
404 if (depth == 0) {
405 /* leaf entries */
406 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
407 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
408 ext4_fsblk_t pblock = 0;
409 ext4_lblk_t lblock = 0;
410 ext4_lblk_t prev = 0;
411 int len = 0;
412 while (entries) {
413 if (!ext4_valid_extent(inode, ext))
414 return 0;
415
416 /* Check for overlapping extents */
417 lblock = le32_to_cpu(ext->ee_block);
418 len = ext4_ext_get_actual_len(ext);
419 if ((lblock <= prev) && prev) {
420 pblock = ext4_ext_pblock(ext);
421 es->s_last_error_block = cpu_to_le64(pblock);
422 return 0;
423 }
424 ext++;
425 entries--;
426 prev = lblock + len - 1;
427 }
428 } else {
429 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
430 while (entries) {
431 if (!ext4_valid_extent_idx(inode, ext_idx))
432 return 0;
433 ext_idx++;
434 entries--;
435 }
436 }
437 return 1;
438}
439
440static int __ext4_ext_check(const char *function, unsigned int line,
441 struct inode *inode, struct ext4_extent_header *eh,
442 int depth, ext4_fsblk_t pblk)
443{
444 const char *error_msg;
445 int max = 0, err = -EFSCORRUPTED;
446
447 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
448 error_msg = "invalid magic";
449 goto corrupted;
450 }
451 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
452 error_msg = "unexpected eh_depth";
453 goto corrupted;
454 }
455 if (unlikely(eh->eh_max == 0)) {
456 error_msg = "invalid eh_max";
457 goto corrupted;
458 }
459 max = ext4_ext_max_entries(inode, depth);
460 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
461 error_msg = "too large eh_max";
462 goto corrupted;
463 }
464 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
465 error_msg = "invalid eh_entries";
466 goto corrupted;
467 }
468 if (!ext4_valid_extent_entries(inode, eh, depth)) {
469 error_msg = "invalid extent entries";
470 goto corrupted;
471 }
472 /* Verify checksum on non-root extent tree nodes */
473 if (ext_depth(inode) != depth &&
474 !ext4_extent_block_csum_verify(inode, eh)) {
475 error_msg = "extent tree corrupted";
476 err = -EFSBADCRC;
477 goto corrupted;
478 }
479 return 0;
480
481corrupted:
482 ext4_error_inode(inode, function, line, 0,
483 "pblk %llu bad header/extent: %s - magic %x, "
484 "entries %u, max %u(%u), depth %u(%u)",
485 (unsigned long long) pblk, error_msg,
486 le16_to_cpu(eh->eh_magic),
487 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
488 max, le16_to_cpu(eh->eh_depth), depth);
489 return err;
490}
491
492#define ext4_ext_check(inode, eh, depth, pblk) \
493 __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
494
495int ext4_ext_check_inode(struct inode *inode)
496{
497 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
498}
499
500static struct buffer_head *
501__read_extent_tree_block(const char *function, unsigned int line,
502 struct inode *inode, ext4_fsblk_t pblk, int depth,
503 int flags)
504{
505 struct buffer_head *bh;
506 int err;
507
508 bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
509 if (unlikely(!bh))
510 return ERR_PTR(-ENOMEM);
511
512 if (!bh_uptodate_or_lock(bh)) {
513 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
514 err = bh_submit_read(bh);
515 if (err < 0)
516 goto errout;
517 }
518 if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
519 return bh;
520 err = __ext4_ext_check(function, line, inode,
521 ext_block_hdr(bh), depth, pblk);
522 if (err)
523 goto errout;
524 set_buffer_verified(bh);
525 /*
526 * If this is a leaf block, cache all of its entries
527 */
528 if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
529 struct ext4_extent_header *eh = ext_block_hdr(bh);
530 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
531 ext4_lblk_t prev = 0;
532 int i;
533
534 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
535 unsigned int status = EXTENT_STATUS_WRITTEN;
536 ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
537 int len = ext4_ext_get_actual_len(ex);
538
539 if (prev && (prev != lblk))
540 ext4_es_cache_extent(inode, prev,
541 lblk - prev, ~0,
542 EXTENT_STATUS_HOLE);
543
544 if (ext4_ext_is_unwritten(ex))
545 status = EXTENT_STATUS_UNWRITTEN;
546 ext4_es_cache_extent(inode, lblk, len,
547 ext4_ext_pblock(ex), status);
548 prev = lblk + len;
549 }
550 }
551 return bh;
552errout:
553 put_bh(bh);
554 return ERR_PTR(err);
555
556}
557
558#define read_extent_tree_block(inode, pblk, depth, flags) \
559 __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \
560 (depth), (flags))
561
562/*
563 * This function is called to cache a file's extent information in the
564 * extent status tree
565 */
566int ext4_ext_precache(struct inode *inode)
567{
568 struct ext4_inode_info *ei = EXT4_I(inode);
569 struct ext4_ext_path *path = NULL;
570 struct buffer_head *bh;
571 int i = 0, depth, ret = 0;
572
573 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
574 return 0; /* not an extent-mapped inode */
575
576 down_read(&ei->i_data_sem);
577 depth = ext_depth(inode);
578
579 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
580 GFP_NOFS);
581 if (path == NULL) {
582 up_read(&ei->i_data_sem);
583 return -ENOMEM;
584 }
585
586 /* Don't cache anything if there are no external extent blocks */
587 if (depth == 0)
588 goto out;
589 path[0].p_hdr = ext_inode_hdr(inode);
590 ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
591 if (ret)
592 goto out;
593 path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
594 while (i >= 0) {
595 /*
596 * If this is a leaf block or we've reached the end of
597 * the index block, go up
598 */
599 if ((i == depth) ||
600 path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
601 brelse(path[i].p_bh);
602 path[i].p_bh = NULL;
603 i--;
604 continue;
605 }
606 bh = read_extent_tree_block(inode,
607 ext4_idx_pblock(path[i].p_idx++),
608 depth - i - 1,
609 EXT4_EX_FORCE_CACHE);
610 if (IS_ERR(bh)) {
611 ret = PTR_ERR(bh);
612 break;
613 }
614 i++;
615 path[i].p_bh = bh;
616 path[i].p_hdr = ext_block_hdr(bh);
617 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
618 }
619 ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
620out:
621 up_read(&ei->i_data_sem);
622 ext4_ext_drop_refs(path);
623 kfree(path);
624 return ret;
625}
626
627#ifdef EXT_DEBUG
628static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
629{
630 int k, l = path->p_depth;
631
632 ext_debug("path:");
633 for (k = 0; k <= l; k++, path++) {
634 if (path->p_idx) {
635 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
636 ext4_idx_pblock(path->p_idx));
637 } else if (path->p_ext) {
638 ext_debug(" %d:[%d]%d:%llu ",
639 le32_to_cpu(path->p_ext->ee_block),
640 ext4_ext_is_unwritten(path->p_ext),
641 ext4_ext_get_actual_len(path->p_ext),
642 ext4_ext_pblock(path->p_ext));
643 } else
644 ext_debug(" []");
645 }
646 ext_debug("\n");
647}
648
649static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
650{
651 int depth = ext_depth(inode);
652 struct ext4_extent_header *eh;
653 struct ext4_extent *ex;
654 int i;
655
656 if (!path)
657 return;
658
659 eh = path[depth].p_hdr;
660 ex = EXT_FIRST_EXTENT(eh);
661
662 ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
663
664 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
665 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
666 ext4_ext_is_unwritten(ex),
667 ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
668 }
669 ext_debug("\n");
670}
671
672static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
673 ext4_fsblk_t newblock, int level)
674{
675 int depth = ext_depth(inode);
676 struct ext4_extent *ex;
677
678 if (depth != level) {
679 struct ext4_extent_idx *idx;
680 idx = path[level].p_idx;
681 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
682 ext_debug("%d: move %d:%llu in new index %llu\n", level,
683 le32_to_cpu(idx->ei_block),
684 ext4_idx_pblock(idx),
685 newblock);
686 idx++;
687 }
688
689 return;
690 }
691
692 ex = path[depth].p_ext;
693 while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
694 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
695 le32_to_cpu(ex->ee_block),
696 ext4_ext_pblock(ex),
697 ext4_ext_is_unwritten(ex),
698 ext4_ext_get_actual_len(ex),
699 newblock);
700 ex++;
701 }
702}
703
704#else
705#define ext4_ext_show_path(inode, path)
706#define ext4_ext_show_leaf(inode, path)
707#define ext4_ext_show_move(inode, path, newblock, level)
708#endif
709
710void ext4_ext_drop_refs(struct ext4_ext_path *path)
711{
712 int depth, i;
713
714 if (!path)
715 return;
716 depth = path->p_depth;
717 for (i = 0; i <= depth; i++, path++)
718 if (path->p_bh) {
719 brelse(path->p_bh);
720 path->p_bh = NULL;
721 }
722}
723
724/*
725 * ext4_ext_binsearch_idx:
726 * binary search for the closest index of the given block
727 * the header must be checked before calling this
728 */
729static void
730ext4_ext_binsearch_idx(struct inode *inode,
731 struct ext4_ext_path *path, ext4_lblk_t block)
732{
733 struct ext4_extent_header *eh = path->p_hdr;
734 struct ext4_extent_idx *r, *l, *m;
735
736
737 ext_debug("binsearch for %u(idx): ", block);
738
739 l = EXT_FIRST_INDEX(eh) + 1;
740 r = EXT_LAST_INDEX(eh);
741 while (l <= r) {
742 m = l + (r - l) / 2;
743 if (block < le32_to_cpu(m->ei_block))
744 r = m - 1;
745 else
746 l = m + 1;
747 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
748 m, le32_to_cpu(m->ei_block),
749 r, le32_to_cpu(r->ei_block));
750 }
751
752 path->p_idx = l - 1;
753 ext_debug(" -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
754 ext4_idx_pblock(path->p_idx));
755
756#ifdef CHECK_BINSEARCH
757 {
758 struct ext4_extent_idx *chix, *ix;
759 int k;
760
761 chix = ix = EXT_FIRST_INDEX(eh);
762 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
763 if (k != 0 &&
764 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
765 printk(KERN_DEBUG "k=%d, ix=0x%p, "
766 "first=0x%p\n", k,
767 ix, EXT_FIRST_INDEX(eh));
768 printk(KERN_DEBUG "%u <= %u\n",
769 le32_to_cpu(ix->ei_block),
770 le32_to_cpu(ix[-1].ei_block));
771 }
772 BUG_ON(k && le32_to_cpu(ix->ei_block)
773 <= le32_to_cpu(ix[-1].ei_block));
774 if (block < le32_to_cpu(ix->ei_block))
775 break;
776 chix = ix;
777 }
778 BUG_ON(chix != path->p_idx);
779 }
780#endif
781
782}
783
784/*
785 * ext4_ext_binsearch:
786 * binary search for closest extent of the given block
787 * the header must be checked before calling this
788 */
789static void
790ext4_ext_binsearch(struct inode *inode,
791 struct ext4_ext_path *path, ext4_lblk_t block)
792{
793 struct ext4_extent_header *eh = path->p_hdr;
794 struct ext4_extent *r, *l, *m;
795
796 if (eh->eh_entries == 0) {
797 /*
798 * this leaf is empty:
799 * we get such a leaf in split/add case
800 */
801 return;
802 }
803
804 ext_debug("binsearch for %u: ", block);
805
806 l = EXT_FIRST_EXTENT(eh) + 1;
807 r = EXT_LAST_EXTENT(eh);
808
809 while (l <= r) {
810 m = l + (r - l) / 2;
811 if (block < le32_to_cpu(m->ee_block))
812 r = m - 1;
813 else
814 l = m + 1;
815 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
816 m, le32_to_cpu(m->ee_block),
817 r, le32_to_cpu(r->ee_block));
818 }
819
820 path->p_ext = l - 1;
821 ext_debug(" -> %d:%llu:[%d]%d ",
822 le32_to_cpu(path->p_ext->ee_block),
823 ext4_ext_pblock(path->p_ext),
824 ext4_ext_is_unwritten(path->p_ext),
825 ext4_ext_get_actual_len(path->p_ext));
826
827#ifdef CHECK_BINSEARCH
828 {
829 struct ext4_extent *chex, *ex;
830 int k;
831
832 chex = ex = EXT_FIRST_EXTENT(eh);
833 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
834 BUG_ON(k && le32_to_cpu(ex->ee_block)
835 <= le32_to_cpu(ex[-1].ee_block));
836 if (block < le32_to_cpu(ex->ee_block))
837 break;
838 chex = ex;
839 }
840 BUG_ON(chex != path->p_ext);
841 }
842#endif
843
844}
845
846int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
847{
848 struct ext4_extent_header *eh;
849
850 eh = ext_inode_hdr(inode);
851 eh->eh_depth = 0;
852 eh->eh_entries = 0;
853 eh->eh_magic = EXT4_EXT_MAGIC;
854 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
855 ext4_mark_inode_dirty(handle, inode);
856 return 0;
857}
858
859struct ext4_ext_path *
860ext4_find_extent(struct inode *inode, ext4_lblk_t block,
861 struct ext4_ext_path **orig_path, int flags)
862{
863 struct ext4_extent_header *eh;
864 struct buffer_head *bh;
865 struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
866 short int depth, i, ppos = 0;
867 int ret;
868
869 eh = ext_inode_hdr(inode);
870 depth = ext_depth(inode);
871
872 if (path) {
873 ext4_ext_drop_refs(path);
874 if (depth > path[0].p_maxdepth) {
875 kfree(path);
876 *orig_path = path = NULL;
877 }
878 }
879 if (!path) {
880 /* account possible depth increase */
881 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
882 GFP_NOFS);
883 if (unlikely(!path))
884 return ERR_PTR(-ENOMEM);
885 path[0].p_maxdepth = depth + 1;
886 }
887 path[0].p_hdr = eh;
888 path[0].p_bh = NULL;
889
890 i = depth;
891 /* walk through the tree */
892 while (i) {
893 ext_debug("depth %d: num %d, max %d\n",
894 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
895
896 ext4_ext_binsearch_idx(inode, path + ppos, block);
897 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
898 path[ppos].p_depth = i;
899 path[ppos].p_ext = NULL;
900
901 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
902 flags);
903 if (IS_ERR(bh)) {
904 ret = PTR_ERR(bh);
905 goto err;
906 }
907
908 eh = ext_block_hdr(bh);
909 ppos++;
910 if (unlikely(ppos > depth)) {
911 put_bh(bh);
912 EXT4_ERROR_INODE(inode,
913 "ppos %d > depth %d", ppos, depth);
914 ret = -EFSCORRUPTED;
915 goto err;
916 }
917 path[ppos].p_bh = bh;
918 path[ppos].p_hdr = eh;
919 }
920
921 path[ppos].p_depth = i;
922 path[ppos].p_ext = NULL;
923 path[ppos].p_idx = NULL;
924
925 /* find extent */
926 ext4_ext_binsearch(inode, path + ppos, block);
927 /* if not an empty leaf */
928 if (path[ppos].p_ext)
929 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
930
931 ext4_ext_show_path(inode, path);
932
933 return path;
934
935err:
936 ext4_ext_drop_refs(path);
937 kfree(path);
938 if (orig_path)
939 *orig_path = NULL;
940 return ERR_PTR(ret);
941}
942
943/*
944 * ext4_ext_insert_index:
945 * insert new index [@logical;@ptr] into the block at @curp;
946 * check where to insert: before @curp or after @curp
947 */
948static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
949 struct ext4_ext_path *curp,
950 int logical, ext4_fsblk_t ptr)
951{
952 struct ext4_extent_idx *ix;
953 int len, err;
954
955 err = ext4_ext_get_access(handle, inode, curp);
956 if (err)
957 return err;
958
959 if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
960 EXT4_ERROR_INODE(inode,
961 "logical %d == ei_block %d!",
962 logical, le32_to_cpu(curp->p_idx->ei_block));
963 return -EFSCORRUPTED;
964 }
965
966 if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
967 >= le16_to_cpu(curp->p_hdr->eh_max))) {
968 EXT4_ERROR_INODE(inode,
969 "eh_entries %d >= eh_max %d!",
970 le16_to_cpu(curp->p_hdr->eh_entries),
971 le16_to_cpu(curp->p_hdr->eh_max));
972 return -EFSCORRUPTED;
973 }
974
975 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
976 /* insert after */
977 ext_debug("insert new index %d after: %llu\n", logical, ptr);
978 ix = curp->p_idx + 1;
979 } else {
980 /* insert before */
981 ext_debug("insert new index %d before: %llu\n", logical, ptr);
982 ix = curp->p_idx;
983 }
984
985 len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
986 BUG_ON(len < 0);
987 if (len > 0) {
988 ext_debug("insert new index %d: "
989 "move %d indices from 0x%p to 0x%p\n",
990 logical, len, ix, ix + 1);
991 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
992 }
993
994 if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
995 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
996 return -EFSCORRUPTED;
997 }
998
999 ix->ei_block = cpu_to_le32(logical);
1000 ext4_idx_store_pblock(ix, ptr);
1001 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
1002
1003 if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
1004 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
1005 return -EFSCORRUPTED;
1006 }
1007
1008 err = ext4_ext_dirty(handle, inode, curp);
1009 ext4_std_error(inode->i_sb, err);
1010
1011 return err;
1012}
1013
1014/*
1015 * ext4_ext_split:
1016 * inserts new subtree into the path, using free index entry
1017 * at depth @at:
1018 * - allocates all needed blocks (new leaf and all intermediate index blocks)
1019 * - makes decision where to split
1020 * - moves remaining extents and index entries (right to the split point)
1021 * into the newly allocated blocks
1022 * - initializes subtree
1023 */
1024static int ext4_ext_split(handle_t *handle, struct inode *inode,
1025 unsigned int flags,
1026 struct ext4_ext_path *path,
1027 struct ext4_extent *newext, int at)
1028{
1029 struct buffer_head *bh = NULL;
1030 int depth = ext_depth(inode);
1031 struct ext4_extent_header *neh;
1032 struct ext4_extent_idx *fidx;
1033 int i = at, k, m, a;
1034 ext4_fsblk_t newblock, oldblock;
1035 __le32 border;
1036 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1037 int err = 0;
1038
1039 /* make decision: where to split? */
1040 /* FIXME: now decision is simplest: at current extent */
1041
1042 /* if current leaf will be split, then we should use
1043 * border from split point */
1044 if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1045 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1046 return -EFSCORRUPTED;
1047 }
1048 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1049 border = path[depth].p_ext[1].ee_block;
1050 ext_debug("leaf will be split."
1051 " next leaf starts at %d\n",
1052 le32_to_cpu(border));
1053 } else {
1054 border = newext->ee_block;
1055 ext_debug("leaf will be added."
1056 " next leaf starts at %d\n",
1057 le32_to_cpu(border));
1058 }
1059
1060 /*
1061 * If error occurs, then we break processing
1062 * and mark filesystem read-only. index won't
1063 * be inserted and tree will be in consistent
1064 * state. Next mount will repair buffers too.
1065 */
1066
1067 /*
1068 * Get array to track all allocated blocks.
1069 * We need this to handle errors and free blocks
1070 * upon them.
1071 */
1072 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1073 if (!ablocks)
1074 return -ENOMEM;
1075
1076 /* allocate all needed blocks */
1077 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1078 for (a = 0; a < depth - at; a++) {
1079 newblock = ext4_ext_new_meta_block(handle, inode, path,
1080 newext, &err, flags);
1081 if (newblock == 0)
1082 goto cleanup;
1083 ablocks[a] = newblock;
1084 }
1085
1086 /* initialize new leaf */
1087 newblock = ablocks[--a];
1088 if (unlikely(newblock == 0)) {
1089 EXT4_ERROR_INODE(inode, "newblock == 0!");
1090 err = -EFSCORRUPTED;
1091 goto cleanup;
1092 }
1093 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1094 if (unlikely(!bh)) {
1095 err = -ENOMEM;
1096 goto cleanup;
1097 }
1098 lock_buffer(bh);
1099
1100 err = ext4_journal_get_create_access(handle, bh);
1101 if (err)
1102 goto cleanup;
1103
1104 neh = ext_block_hdr(bh);
1105 neh->eh_entries = 0;
1106 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1107 neh->eh_magic = EXT4_EXT_MAGIC;
1108 neh->eh_depth = 0;
1109
1110 /* move remainder of path[depth] to the new leaf */
1111 if (unlikely(path[depth].p_hdr->eh_entries !=
1112 path[depth].p_hdr->eh_max)) {
1113 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1114 path[depth].p_hdr->eh_entries,
1115 path[depth].p_hdr->eh_max);
1116 err = -EFSCORRUPTED;
1117 goto cleanup;
1118 }
1119 /* start copy from next extent */
1120 m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1121 ext4_ext_show_move(inode, path, newblock, depth);
1122 if (m) {
1123 struct ext4_extent *ex;
1124 ex = EXT_FIRST_EXTENT(neh);
1125 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1126 le16_add_cpu(&neh->eh_entries, m);
1127 }
1128
1129 ext4_extent_block_csum_set(inode, neh);
1130 set_buffer_uptodate(bh);
1131 unlock_buffer(bh);
1132
1133 err = ext4_handle_dirty_metadata(handle, inode, bh);
1134 if (err)
1135 goto cleanup;
1136 brelse(bh);
1137 bh = NULL;
1138
1139 /* correct old leaf */
1140 if (m) {
1141 err = ext4_ext_get_access(handle, inode, path + depth);
1142 if (err)
1143 goto cleanup;
1144 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1145 err = ext4_ext_dirty(handle, inode, path + depth);
1146 if (err)
1147 goto cleanup;
1148
1149 }
1150
1151 /* create intermediate indexes */
1152 k = depth - at - 1;
1153 if (unlikely(k < 0)) {
1154 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1155 err = -EFSCORRUPTED;
1156 goto cleanup;
1157 }
1158 if (k)
1159 ext_debug("create %d intermediate indices\n", k);
1160 /* insert new index into current index block */
1161 /* current depth stored in i var */
1162 i = depth - 1;
1163 while (k--) {
1164 oldblock = newblock;
1165 newblock = ablocks[--a];
1166 bh = sb_getblk(inode->i_sb, newblock);
1167 if (unlikely(!bh)) {
1168 err = -ENOMEM;
1169 goto cleanup;
1170 }
1171 lock_buffer(bh);
1172
1173 err = ext4_journal_get_create_access(handle, bh);
1174 if (err)
1175 goto cleanup;
1176
1177 neh = ext_block_hdr(bh);
1178 neh->eh_entries = cpu_to_le16(1);
1179 neh->eh_magic = EXT4_EXT_MAGIC;
1180 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1181 neh->eh_depth = cpu_to_le16(depth - i);
1182 fidx = EXT_FIRST_INDEX(neh);
1183 fidx->ei_block = border;
1184 ext4_idx_store_pblock(fidx, oldblock);
1185
1186 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1187 i, newblock, le32_to_cpu(border), oldblock);
1188
1189 /* move remainder of path[i] to the new index block */
1190 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1191 EXT_LAST_INDEX(path[i].p_hdr))) {
1192 EXT4_ERROR_INODE(inode,
1193 "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1194 le32_to_cpu(path[i].p_ext->ee_block));
1195 err = -EFSCORRUPTED;
1196 goto cleanup;
1197 }
1198 /* start copy indexes */
1199 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1200 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1201 EXT_MAX_INDEX(path[i].p_hdr));
1202 ext4_ext_show_move(inode, path, newblock, i);
1203 if (m) {
1204 memmove(++fidx, path[i].p_idx,
1205 sizeof(struct ext4_extent_idx) * m);
1206 le16_add_cpu(&neh->eh_entries, m);
1207 }
1208 ext4_extent_block_csum_set(inode, neh);
1209 set_buffer_uptodate(bh);
1210 unlock_buffer(bh);
1211
1212 err = ext4_handle_dirty_metadata(handle, inode, bh);
1213 if (err)
1214 goto cleanup;
1215 brelse(bh);
1216 bh = NULL;
1217
1218 /* correct old index */
1219 if (m) {
1220 err = ext4_ext_get_access(handle, inode, path + i);
1221 if (err)
1222 goto cleanup;
1223 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1224 err = ext4_ext_dirty(handle, inode, path + i);
1225 if (err)
1226 goto cleanup;
1227 }
1228
1229 i--;
1230 }
1231
1232 /* insert new index */
1233 err = ext4_ext_insert_index(handle, inode, path + at,
1234 le32_to_cpu(border), newblock);
1235
1236cleanup:
1237 if (bh) {
1238 if (buffer_locked(bh))
1239 unlock_buffer(bh);
1240 brelse(bh);
1241 }
1242
1243 if (err) {
1244 /* free all allocated blocks in error case */
1245 for (i = 0; i < depth; i++) {
1246 if (!ablocks[i])
1247 continue;
1248 ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1249 EXT4_FREE_BLOCKS_METADATA);
1250 }
1251 }
1252 kfree(ablocks);
1253
1254 return err;
1255}
1256
1257/*
1258 * ext4_ext_grow_indepth:
1259 * implements tree growing procedure:
1260 * - allocates new block
1261 * - moves top-level data (index block or leaf) into the new block
1262 * - initializes new top-level, creating index that points to the
1263 * just created block
1264 */
1265static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1266 unsigned int flags)
1267{
1268 struct ext4_extent_header *neh;
1269 struct buffer_head *bh;
1270 ext4_fsblk_t newblock, goal = 0;
1271 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1272 int err = 0;
1273
1274 /* Try to prepend new index to old one */
1275 if (ext_depth(inode))
1276 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1277 if (goal > le32_to_cpu(es->s_first_data_block)) {
1278 flags |= EXT4_MB_HINT_TRY_GOAL;
1279 goal--;
1280 } else
1281 goal = ext4_inode_to_goal_block(inode);
1282 newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1283 NULL, &err);
1284 if (newblock == 0)
1285 return err;
1286
1287 bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1288 if (unlikely(!bh))
1289 return -ENOMEM;
1290 lock_buffer(bh);
1291
1292 err = ext4_journal_get_create_access(handle, bh);
1293 if (err) {
1294 unlock_buffer(bh);
1295 goto out;
1296 }
1297
1298 /* move top-level index/leaf into new block */
1299 memmove(bh->b_data, EXT4_I(inode)->i_data,
1300 sizeof(EXT4_I(inode)->i_data));
1301
1302 /* set size of new block */
1303 neh = ext_block_hdr(bh);
1304 /* old root could have indexes or leaves
1305 * so calculate e_max right way */
1306 if (ext_depth(inode))
1307 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1308 else
1309 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1310 neh->eh_magic = EXT4_EXT_MAGIC;
1311 ext4_extent_block_csum_set(inode, neh);
1312 set_buffer_uptodate(bh);
1313 unlock_buffer(bh);
1314
1315 err = ext4_handle_dirty_metadata(handle, inode, bh);
1316 if (err)
1317 goto out;
1318
1319 /* Update top-level index: num,max,pointer */
1320 neh = ext_inode_hdr(inode);
1321 neh->eh_entries = cpu_to_le16(1);
1322 ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1323 if (neh->eh_depth == 0) {
1324 /* Root extent block becomes index block */
1325 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1326 EXT_FIRST_INDEX(neh)->ei_block =
1327 EXT_FIRST_EXTENT(neh)->ee_block;
1328 }
1329 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1330 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1331 le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1332 ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1333
1334 le16_add_cpu(&neh->eh_depth, 1);
1335 ext4_mark_inode_dirty(handle, inode);
1336out:
1337 brelse(bh);
1338
1339 return err;
1340}
1341
1342/*
1343 * ext4_ext_create_new_leaf:
1344 * finds empty index and adds new leaf.
1345 * if no free index is found, then it requests in-depth growing.
1346 */
1347static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1348 unsigned int mb_flags,
1349 unsigned int gb_flags,
1350 struct ext4_ext_path **ppath,
1351 struct ext4_extent *newext)
1352{
1353 struct ext4_ext_path *path = *ppath;
1354 struct ext4_ext_path *curp;
1355 int depth, i, err = 0;
1356
1357repeat:
1358 i = depth = ext_depth(inode);
1359
1360 /* walk up to the tree and look for free index entry */
1361 curp = path + depth;
1362 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1363 i--;
1364 curp--;
1365 }
1366
1367 /* we use already allocated block for index block,
1368 * so subsequent data blocks should be contiguous */
1369 if (EXT_HAS_FREE_INDEX(curp)) {
1370 /* if we found index with free entry, then use that
1371 * entry: create all needed subtree and add new leaf */
1372 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1373 if (err)
1374 goto out;
1375
1376 /* refill path */
1377 path = ext4_find_extent(inode,
1378 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1379 ppath, gb_flags);
1380 if (IS_ERR(path))
1381 err = PTR_ERR(path);
1382 } else {
1383 /* tree is full, time to grow in depth */
1384 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1385 if (err)
1386 goto out;
1387
1388 /* refill path */
1389 path = ext4_find_extent(inode,
1390 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1391 ppath, gb_flags);
1392 if (IS_ERR(path)) {
1393 err = PTR_ERR(path);
1394 goto out;
1395 }
1396
1397 /*
1398 * only first (depth 0 -> 1) produces free space;
1399 * in all other cases we have to split the grown tree
1400 */
1401 depth = ext_depth(inode);
1402 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1403 /* now we need to split */
1404 goto repeat;
1405 }
1406 }
1407
1408out:
1409 return err;
1410}
1411
1412/*
1413 * search the closest allocated block to the left for *logical
1414 * and returns it at @logical + it's physical address at @phys
1415 * if *logical is the smallest allocated block, the function
1416 * returns 0 at @phys
1417 * return value contains 0 (success) or error code
1418 */
1419static int ext4_ext_search_left(struct inode *inode,
1420 struct ext4_ext_path *path,
1421 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1422{
1423 struct ext4_extent_idx *ix;
1424 struct ext4_extent *ex;
1425 int depth, ee_len;
1426
1427 if (unlikely(path == NULL)) {
1428 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1429 return -EFSCORRUPTED;
1430 }
1431 depth = path->p_depth;
1432 *phys = 0;
1433
1434 if (depth == 0 && path->p_ext == NULL)
1435 return 0;
1436
1437 /* usually extent in the path covers blocks smaller
1438 * then *logical, but it can be that extent is the
1439 * first one in the file */
1440
1441 ex = path[depth].p_ext;
1442 ee_len = ext4_ext_get_actual_len(ex);
1443 if (*logical < le32_to_cpu(ex->ee_block)) {
1444 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1445 EXT4_ERROR_INODE(inode,
1446 "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1447 *logical, le32_to_cpu(ex->ee_block));
1448 return -EFSCORRUPTED;
1449 }
1450 while (--depth >= 0) {
1451 ix = path[depth].p_idx;
1452 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1453 EXT4_ERROR_INODE(inode,
1454 "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1455 ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1456 EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1457 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1458 depth);
1459 return -EFSCORRUPTED;
1460 }
1461 }
1462 return 0;
1463 }
1464
1465 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1466 EXT4_ERROR_INODE(inode,
1467 "logical %d < ee_block %d + ee_len %d!",
1468 *logical, le32_to_cpu(ex->ee_block), ee_len);
1469 return -EFSCORRUPTED;
1470 }
1471
1472 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1473 *phys = ext4_ext_pblock(ex) + ee_len - 1;
1474 return 0;
1475}
1476
1477/*
1478 * search the closest allocated block to the right for *logical
1479 * and returns it at @logical + it's physical address at @phys
1480 * if *logical is the largest allocated block, the function
1481 * returns 0 at @phys
1482 * return value contains 0 (success) or error code
1483 */
1484static int ext4_ext_search_right(struct inode *inode,
1485 struct ext4_ext_path *path,
1486 ext4_lblk_t *logical, ext4_fsblk_t *phys,
1487 struct ext4_extent **ret_ex)
1488{
1489 struct buffer_head *bh = NULL;
1490 struct ext4_extent_header *eh;
1491 struct ext4_extent_idx *ix;
1492 struct ext4_extent *ex;
1493 ext4_fsblk_t block;
1494 int depth; /* Note, NOT eh_depth; depth from top of tree */
1495 int ee_len;
1496
1497 if (unlikely(path == NULL)) {
1498 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1499 return -EFSCORRUPTED;
1500 }
1501 depth = path->p_depth;
1502 *phys = 0;
1503
1504 if (depth == 0 && path->p_ext == NULL)
1505 return 0;
1506
1507 /* usually extent in the path covers blocks smaller
1508 * then *logical, but it can be that extent is the
1509 * first one in the file */
1510
1511 ex = path[depth].p_ext;
1512 ee_len = ext4_ext_get_actual_len(ex);
1513 if (*logical < le32_to_cpu(ex->ee_block)) {
1514 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1515 EXT4_ERROR_INODE(inode,
1516 "first_extent(path[%d].p_hdr) != ex",
1517 depth);
1518 return -EFSCORRUPTED;
1519 }
1520 while (--depth >= 0) {
1521 ix = path[depth].p_idx;
1522 if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1523 EXT4_ERROR_INODE(inode,
1524 "ix != EXT_FIRST_INDEX *logical %d!",
1525 *logical);
1526 return -EFSCORRUPTED;
1527 }
1528 }
1529 goto found_extent;
1530 }
1531
1532 if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1533 EXT4_ERROR_INODE(inode,
1534 "logical %d < ee_block %d + ee_len %d!",
1535 *logical, le32_to_cpu(ex->ee_block), ee_len);
1536 return -EFSCORRUPTED;
1537 }
1538
1539 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1540 /* next allocated block in this leaf */
1541 ex++;
1542 goto found_extent;
1543 }
1544
1545 /* go up and search for index to the right */
1546 while (--depth >= 0) {
1547 ix = path[depth].p_idx;
1548 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1549 goto got_index;
1550 }
1551
1552 /* we've gone up to the root and found no index to the right */
1553 return 0;
1554
1555got_index:
1556 /* we've found index to the right, let's
1557 * follow it and find the closest allocated
1558 * block to the right */
1559 ix++;
1560 block = ext4_idx_pblock(ix);
1561 while (++depth < path->p_depth) {
1562 /* subtract from p_depth to get proper eh_depth */
1563 bh = read_extent_tree_block(inode, block,
1564 path->p_depth - depth, 0);
1565 if (IS_ERR(bh))
1566 return PTR_ERR(bh);
1567 eh = ext_block_hdr(bh);
1568 ix = EXT_FIRST_INDEX(eh);
1569 block = ext4_idx_pblock(ix);
1570 put_bh(bh);
1571 }
1572
1573 bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1574 if (IS_ERR(bh))
1575 return PTR_ERR(bh);
1576 eh = ext_block_hdr(bh);
1577 ex = EXT_FIRST_EXTENT(eh);
1578found_extent:
1579 *logical = le32_to_cpu(ex->ee_block);
1580 *phys = ext4_ext_pblock(ex);
1581 *ret_ex = ex;
1582 if (bh)
1583 put_bh(bh);
1584 return 0;
1585}
1586
1587/*
1588 * ext4_ext_next_allocated_block:
1589 * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1590 * NOTE: it considers block number from index entry as
1591 * allocated block. Thus, index entries have to be consistent
1592 * with leaves.
1593 */
1594ext4_lblk_t
1595ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1596{
1597 int depth;
1598
1599 BUG_ON(path == NULL);
1600 depth = path->p_depth;
1601
1602 if (depth == 0 && path->p_ext == NULL)
1603 return EXT_MAX_BLOCKS;
1604
1605 while (depth >= 0) {
1606 if (depth == path->p_depth) {
1607 /* leaf */
1608 if (path[depth].p_ext &&
1609 path[depth].p_ext !=
1610 EXT_LAST_EXTENT(path[depth].p_hdr))
1611 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1612 } else {
1613 /* index */
1614 if (path[depth].p_idx !=
1615 EXT_LAST_INDEX(path[depth].p_hdr))
1616 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1617 }
1618 depth--;
1619 }
1620
1621 return EXT_MAX_BLOCKS;
1622}
1623
1624/*
1625 * ext4_ext_next_leaf_block:
1626 * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1627 */
1628static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1629{
1630 int depth;
1631
1632 BUG_ON(path == NULL);
1633 depth = path->p_depth;
1634
1635 /* zero-tree has no leaf blocks at all */
1636 if (depth == 0)
1637 return EXT_MAX_BLOCKS;
1638
1639 /* go to index block */
1640 depth--;
1641
1642 while (depth >= 0) {
1643 if (path[depth].p_idx !=
1644 EXT_LAST_INDEX(path[depth].p_hdr))
1645 return (ext4_lblk_t)
1646 le32_to_cpu(path[depth].p_idx[1].ei_block);
1647 depth--;
1648 }
1649
1650 return EXT_MAX_BLOCKS;
1651}
1652
1653/*
1654 * ext4_ext_correct_indexes:
1655 * if leaf gets modified and modified extent is first in the leaf,
1656 * then we have to correct all indexes above.
1657 * TODO: do we need to correct tree in all cases?
1658 */
1659static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1660 struct ext4_ext_path *path)
1661{
1662 struct ext4_extent_header *eh;
1663 int depth = ext_depth(inode);
1664 struct ext4_extent *ex;
1665 __le32 border;
1666 int k, err = 0;
1667
1668 eh = path[depth].p_hdr;
1669 ex = path[depth].p_ext;
1670
1671 if (unlikely(ex == NULL || eh == NULL)) {
1672 EXT4_ERROR_INODE(inode,
1673 "ex %p == NULL or eh %p == NULL", ex, eh);
1674 return -EFSCORRUPTED;
1675 }
1676
1677 if (depth == 0) {
1678 /* there is no tree at all */
1679 return 0;
1680 }
1681
1682 if (ex != EXT_FIRST_EXTENT(eh)) {
1683 /* we correct tree if first leaf got modified only */
1684 return 0;
1685 }
1686
1687 /*
1688 * TODO: we need correction if border is smaller than current one
1689 */
1690 k = depth - 1;
1691 border = path[depth].p_ext->ee_block;
1692 err = ext4_ext_get_access(handle, inode, path + k);
1693 if (err)
1694 return err;
1695 path[k].p_idx->ei_block = border;
1696 err = ext4_ext_dirty(handle, inode, path + k);
1697 if (err)
1698 return err;
1699
1700 while (k--) {
1701 /* change all left-side indexes */
1702 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1703 break;
1704 err = ext4_ext_get_access(handle, inode, path + k);
1705 if (err)
1706 break;
1707 path[k].p_idx->ei_block = border;
1708 err = ext4_ext_dirty(handle, inode, path + k);
1709 if (err)
1710 break;
1711 }
1712
1713 return err;
1714}
1715
1716int
1717ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1718 struct ext4_extent *ex2)
1719{
1720 unsigned short ext1_ee_len, ext2_ee_len;
1721
1722 if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1723 return 0;
1724
1725 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1726 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1727
1728 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1729 le32_to_cpu(ex2->ee_block))
1730 return 0;
1731
1732 /*
1733 * To allow future support for preallocated extents to be added
1734 * as an RO_COMPAT feature, refuse to merge to extents if
1735 * this can result in the top bit of ee_len being set.
1736 */
1737 if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1738 return 0;
1739 /*
1740 * The check for IO to unwritten extent is somewhat racy as we
1741 * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after
1742 * dropping i_data_sem. But reserved blocks should save us in that
1743 * case.
1744 */
1745 if (ext4_ext_is_unwritten(ex1) &&
1746 (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
1747 atomic_read(&EXT4_I(inode)->i_unwritten) ||
1748 (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)))
1749 return 0;
1750#ifdef AGGRESSIVE_TEST
1751 if (ext1_ee_len >= 4)
1752 return 0;
1753#endif
1754
1755 if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1756 return 1;
1757 return 0;
1758}
1759
1760/*
1761 * This function tries to merge the "ex" extent to the next extent in the tree.
1762 * It always tries to merge towards right. If you want to merge towards
1763 * left, pass "ex - 1" as argument instead of "ex".
1764 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1765 * 1 if they got merged.
1766 */
1767static int ext4_ext_try_to_merge_right(struct inode *inode,
1768 struct ext4_ext_path *path,
1769 struct ext4_extent *ex)
1770{
1771 struct ext4_extent_header *eh;
1772 unsigned int depth, len;
1773 int merge_done = 0, unwritten;
1774
1775 depth = ext_depth(inode);
1776 BUG_ON(path[depth].p_hdr == NULL);
1777 eh = path[depth].p_hdr;
1778
1779 while (ex < EXT_LAST_EXTENT(eh)) {
1780 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1781 break;
1782 /* merge with next extent! */
1783 unwritten = ext4_ext_is_unwritten(ex);
1784 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1785 + ext4_ext_get_actual_len(ex + 1));
1786 if (unwritten)
1787 ext4_ext_mark_unwritten(ex);
1788
1789 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1790 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1791 * sizeof(struct ext4_extent);
1792 memmove(ex + 1, ex + 2, len);
1793 }
1794 le16_add_cpu(&eh->eh_entries, -1);
1795 merge_done = 1;
1796 WARN_ON(eh->eh_entries == 0);
1797 if (!eh->eh_entries)
1798 EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1799 }
1800
1801 return merge_done;
1802}
1803
1804/*
1805 * This function does a very simple check to see if we can collapse
1806 * an extent tree with a single extent tree leaf block into the inode.
1807 */
1808static void ext4_ext_try_to_merge_up(handle_t *handle,
1809 struct inode *inode,
1810 struct ext4_ext_path *path)
1811{
1812 size_t s;
1813 unsigned max_root = ext4_ext_space_root(inode, 0);
1814 ext4_fsblk_t blk;
1815
1816 if ((path[0].p_depth != 1) ||
1817 (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1818 (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1819 return;
1820
1821 /*
1822 * We need to modify the block allocation bitmap and the block
1823 * group descriptor to release the extent tree block. If we
1824 * can't get the journal credits, give up.
1825 */
1826 if (ext4_journal_extend(handle, 2))
1827 return;
1828
1829 /*
1830 * Copy the extent data up to the inode
1831 */
1832 blk = ext4_idx_pblock(path[0].p_idx);
1833 s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1834 sizeof(struct ext4_extent_idx);
1835 s += sizeof(struct ext4_extent_header);
1836
1837 path[1].p_maxdepth = path[0].p_maxdepth;
1838 memcpy(path[0].p_hdr, path[1].p_hdr, s);
1839 path[0].p_depth = 0;
1840 path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1841 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1842 path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1843
1844 brelse(path[1].p_bh);
1845 ext4_free_blocks(handle, inode, NULL, blk, 1,
1846 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1847}
1848
1849/*
1850 * This function tries to merge the @ex extent to neighbours in the tree.
1851 * return 1 if merge left else 0.
1852 */
1853static void ext4_ext_try_to_merge(handle_t *handle,
1854 struct inode *inode,
1855 struct ext4_ext_path *path,
1856 struct ext4_extent *ex) {
1857 struct ext4_extent_header *eh;
1858 unsigned int depth;
1859 int merge_done = 0;
1860
1861 depth = ext_depth(inode);
1862 BUG_ON(path[depth].p_hdr == NULL);
1863 eh = path[depth].p_hdr;
1864
1865 if (ex > EXT_FIRST_EXTENT(eh))
1866 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1867
1868 if (!merge_done)
1869 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1870
1871 ext4_ext_try_to_merge_up(handle, inode, path);
1872}
1873
1874/*
1875 * check if a portion of the "newext" extent overlaps with an
1876 * existing extent.
1877 *
1878 * If there is an overlap discovered, it updates the length of the newext
1879 * such that there will be no overlap, and then returns 1.
1880 * If there is no overlap found, it returns 0.
1881 */
1882static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1883 struct inode *inode,
1884 struct ext4_extent *newext,
1885 struct ext4_ext_path *path)
1886{
1887 ext4_lblk_t b1, b2;
1888 unsigned int depth, len1;
1889 unsigned int ret = 0;
1890
1891 b1 = le32_to_cpu(newext->ee_block);
1892 len1 = ext4_ext_get_actual_len(newext);
1893 depth = ext_depth(inode);
1894 if (!path[depth].p_ext)
1895 goto out;
1896 b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1897
1898 /*
1899 * get the next allocated block if the extent in the path
1900 * is before the requested block(s)
1901 */
1902 if (b2 < b1) {
1903 b2 = ext4_ext_next_allocated_block(path);
1904 if (b2 == EXT_MAX_BLOCKS)
1905 goto out;
1906 b2 = EXT4_LBLK_CMASK(sbi, b2);
1907 }
1908
1909 /* check for wrap through zero on extent logical start block*/
1910 if (b1 + len1 < b1) {
1911 len1 = EXT_MAX_BLOCKS - b1;
1912 newext->ee_len = cpu_to_le16(len1);
1913 ret = 1;
1914 }
1915
1916 /* check for overlap */
1917 if (b1 + len1 > b2) {
1918 newext->ee_len = cpu_to_le16(b2 - b1);
1919 ret = 1;
1920 }
1921out:
1922 return ret;
1923}
1924
1925/*
1926 * ext4_ext_insert_extent:
1927 * tries to merge requsted extent into the existing extent or
1928 * inserts requested extent as new one into the tree,
1929 * creating new leaf in the no-space case.
1930 */
1931int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1932 struct ext4_ext_path **ppath,
1933 struct ext4_extent *newext, int gb_flags)
1934{
1935 struct ext4_ext_path *path = *ppath;
1936 struct ext4_extent_header *eh;
1937 struct ext4_extent *ex, *fex;
1938 struct ext4_extent *nearex; /* nearest extent */
1939 struct ext4_ext_path *npath = NULL;
1940 int depth, len, err;
1941 ext4_lblk_t next;
1942 int mb_flags = 0, unwritten;
1943
1944 if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1945 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1946 if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1947 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1948 return -EFSCORRUPTED;
1949 }
1950 depth = ext_depth(inode);
1951 ex = path[depth].p_ext;
1952 eh = path[depth].p_hdr;
1953 if (unlikely(path[depth].p_hdr == NULL)) {
1954 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1955 return -EFSCORRUPTED;
1956 }
1957
1958 /* try to insert block into found extent and return */
1959 if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1960
1961 /*
1962 * Try to see whether we should rather test the extent on
1963 * right from ex, or from the left of ex. This is because
1964 * ext4_find_extent() can return either extent on the
1965 * left, or on the right from the searched position. This
1966 * will make merging more effective.
1967 */
1968 if (ex < EXT_LAST_EXTENT(eh) &&
1969 (le32_to_cpu(ex->ee_block) +
1970 ext4_ext_get_actual_len(ex) <
1971 le32_to_cpu(newext->ee_block))) {
1972 ex += 1;
1973 goto prepend;
1974 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1975 (le32_to_cpu(newext->ee_block) +
1976 ext4_ext_get_actual_len(newext) <
1977 le32_to_cpu(ex->ee_block)))
1978 ex -= 1;
1979
1980 /* Try to append newex to the ex */
1981 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1982 ext_debug("append [%d]%d block to %u:[%d]%d"
1983 "(from %llu)\n",
1984 ext4_ext_is_unwritten(newext),
1985 ext4_ext_get_actual_len(newext),
1986 le32_to_cpu(ex->ee_block),
1987 ext4_ext_is_unwritten(ex),
1988 ext4_ext_get_actual_len(ex),
1989 ext4_ext_pblock(ex));
1990 err = ext4_ext_get_access(handle, inode,
1991 path + depth);
1992 if (err)
1993 return err;
1994 unwritten = ext4_ext_is_unwritten(ex);
1995 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1996 + ext4_ext_get_actual_len(newext));
1997 if (unwritten)
1998 ext4_ext_mark_unwritten(ex);
1999 eh = path[depth].p_hdr;
2000 nearex = ex;
2001 goto merge;
2002 }
2003
2004prepend:
2005 /* Try to prepend newex to the ex */
2006 if (ext4_can_extents_be_merged(inode, newext, ex)) {
2007 ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
2008 "(from %llu)\n",
2009 le32_to_cpu(newext->ee_block),
2010 ext4_ext_is_unwritten(newext),
2011 ext4_ext_get_actual_len(newext),
2012 le32_to_cpu(ex->ee_block),
2013 ext4_ext_is_unwritten(ex),
2014 ext4_ext_get_actual_len(ex),
2015 ext4_ext_pblock(ex));
2016 err = ext4_ext_get_access(handle, inode,
2017 path + depth);
2018 if (err)
2019 return err;
2020
2021 unwritten = ext4_ext_is_unwritten(ex);
2022 ex->ee_block = newext->ee_block;
2023 ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2024 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2025 + ext4_ext_get_actual_len(newext));
2026 if (unwritten)
2027 ext4_ext_mark_unwritten(ex);
2028 eh = path[depth].p_hdr;
2029 nearex = ex;
2030 goto merge;
2031 }
2032 }
2033
2034 depth = ext_depth(inode);
2035 eh = path[depth].p_hdr;
2036 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2037 goto has_space;
2038
2039 /* probably next leaf has space for us? */
2040 fex = EXT_LAST_EXTENT(eh);
2041 next = EXT_MAX_BLOCKS;
2042 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2043 next = ext4_ext_next_leaf_block(path);
2044 if (next != EXT_MAX_BLOCKS) {
2045 ext_debug("next leaf block - %u\n", next);
2046 BUG_ON(npath != NULL);
2047 npath = ext4_find_extent(inode, next, NULL, 0);
2048 if (IS_ERR(npath))
2049 return PTR_ERR(npath);
2050 BUG_ON(npath->p_depth != path->p_depth);
2051 eh = npath[depth].p_hdr;
2052 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2053 ext_debug("next leaf isn't full(%d)\n",
2054 le16_to_cpu(eh->eh_entries));
2055 path = npath;
2056 goto has_space;
2057 }
2058 ext_debug("next leaf has no free space(%d,%d)\n",
2059 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2060 }
2061
2062 /*
2063 * There is no free space in the found leaf.
2064 * We're gonna add a new leaf in the tree.
2065 */
2066 if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2067 mb_flags |= EXT4_MB_USE_RESERVED;
2068 err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2069 ppath, newext);
2070 if (err)
2071 goto cleanup;
2072 depth = ext_depth(inode);
2073 eh = path[depth].p_hdr;
2074
2075has_space:
2076 nearex = path[depth].p_ext;
2077
2078 err = ext4_ext_get_access(handle, inode, path + depth);
2079 if (err)
2080 goto cleanup;
2081
2082 if (!nearex) {
2083 /* there is no extent in this leaf, create first one */
2084 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2085 le32_to_cpu(newext->ee_block),
2086 ext4_ext_pblock(newext),
2087 ext4_ext_is_unwritten(newext),
2088 ext4_ext_get_actual_len(newext));
2089 nearex = EXT_FIRST_EXTENT(eh);
2090 } else {
2091 if (le32_to_cpu(newext->ee_block)
2092 > le32_to_cpu(nearex->ee_block)) {
2093 /* Insert after */
2094 ext_debug("insert %u:%llu:[%d]%d before: "
2095 "nearest %p\n",
2096 le32_to_cpu(newext->ee_block),
2097 ext4_ext_pblock(newext),
2098 ext4_ext_is_unwritten(newext),
2099 ext4_ext_get_actual_len(newext),
2100 nearex);
2101 nearex++;
2102 } else {
2103 /* Insert before */
2104 BUG_ON(newext->ee_block == nearex->ee_block);
2105 ext_debug("insert %u:%llu:[%d]%d after: "
2106 "nearest %p\n",
2107 le32_to_cpu(newext->ee_block),
2108 ext4_ext_pblock(newext),
2109 ext4_ext_is_unwritten(newext),
2110 ext4_ext_get_actual_len(newext),
2111 nearex);
2112 }
2113 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2114 if (len > 0) {
2115 ext_debug("insert %u:%llu:[%d]%d: "
2116 "move %d extents from 0x%p to 0x%p\n",
2117 le32_to_cpu(newext->ee_block),
2118 ext4_ext_pblock(newext),
2119 ext4_ext_is_unwritten(newext),
2120 ext4_ext_get_actual_len(newext),
2121 len, nearex, nearex + 1);
2122 memmove(nearex + 1, nearex,
2123 len * sizeof(struct ext4_extent));
2124 }
2125 }
2126
2127 le16_add_cpu(&eh->eh_entries, 1);
2128 path[depth].p_ext = nearex;
2129 nearex->ee_block = newext->ee_block;
2130 ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2131 nearex->ee_len = newext->ee_len;
2132
2133merge:
2134 /* try to merge extents */
2135 if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2136 ext4_ext_try_to_merge(handle, inode, path, nearex);
2137
2138
2139 /* time to correct all indexes above */
2140 err = ext4_ext_correct_indexes(handle, inode, path);
2141 if (err)
2142 goto cleanup;
2143
2144 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2145
2146cleanup:
2147 ext4_ext_drop_refs(npath);
2148 kfree(npath);
2149 return err;
2150}
2151
2152static int ext4_fill_fiemap_extents(struct inode *inode,
2153 ext4_lblk_t block, ext4_lblk_t num,
2154 struct fiemap_extent_info *fieinfo)
2155{
2156 struct ext4_ext_path *path = NULL;
2157 struct ext4_extent *ex;
2158 struct extent_status es;
2159 ext4_lblk_t next, next_del, start = 0, end = 0;
2160 ext4_lblk_t last = block + num;
2161 int exists, depth = 0, err = 0;
2162 unsigned int flags = 0;
2163 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2164
2165 while (block < last && block != EXT_MAX_BLOCKS) {
2166 num = last - block;
2167 /* find extent for this block */
2168 down_read(&EXT4_I(inode)->i_data_sem);
2169
2170 path = ext4_find_extent(inode, block, &path, 0);
2171 if (IS_ERR(path)) {
2172 up_read(&EXT4_I(inode)->i_data_sem);
2173 err = PTR_ERR(path);
2174 path = NULL;
2175 break;
2176 }
2177
2178 depth = ext_depth(inode);
2179 if (unlikely(path[depth].p_hdr == NULL)) {
2180 up_read(&EXT4_I(inode)->i_data_sem);
2181 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2182 err = -EFSCORRUPTED;
2183 break;
2184 }
2185 ex = path[depth].p_ext;
2186 next = ext4_ext_next_allocated_block(path);
2187
2188 flags = 0;
2189 exists = 0;
2190 if (!ex) {
2191 /* there is no extent yet, so try to allocate
2192 * all requested space */
2193 start = block;
2194 end = block + num;
2195 } else if (le32_to_cpu(ex->ee_block) > block) {
2196 /* need to allocate space before found extent */
2197 start = block;
2198 end = le32_to_cpu(ex->ee_block);
2199 if (block + num < end)
2200 end = block + num;
2201 } else if (block >= le32_to_cpu(ex->ee_block)
2202 + ext4_ext_get_actual_len(ex)) {
2203 /* need to allocate space after found extent */
2204 start = block;
2205 end = block + num;
2206 if (end >= next)
2207 end = next;
2208 } else if (block >= le32_to_cpu(ex->ee_block)) {
2209 /*
2210 * some part of requested space is covered
2211 * by found extent
2212 */
2213 start = block;
2214 end = le32_to_cpu(ex->ee_block)
2215 + ext4_ext_get_actual_len(ex);
2216 if (block + num < end)
2217 end = block + num;
2218 exists = 1;
2219 } else {
2220 BUG();
2221 }
2222 BUG_ON(end <= start);
2223
2224 if (!exists) {
2225 es.es_lblk = start;
2226 es.es_len = end - start;
2227 es.es_pblk = 0;
2228 } else {
2229 es.es_lblk = le32_to_cpu(ex->ee_block);
2230 es.es_len = ext4_ext_get_actual_len(ex);
2231 es.es_pblk = ext4_ext_pblock(ex);
2232 if (ext4_ext_is_unwritten(ex))
2233 flags |= FIEMAP_EXTENT_UNWRITTEN;
2234 }
2235
2236 /*
2237 * Find delayed extent and update es accordingly. We call
2238 * it even in !exists case to find out whether es is the
2239 * last existing extent or not.
2240 */
2241 next_del = ext4_find_delayed_extent(inode, &es);
2242 if (!exists && next_del) {
2243 exists = 1;
2244 flags |= (FIEMAP_EXTENT_DELALLOC |
2245 FIEMAP_EXTENT_UNKNOWN);
2246 }
2247 up_read(&EXT4_I(inode)->i_data_sem);
2248
2249 if (unlikely(es.es_len == 0)) {
2250 EXT4_ERROR_INODE(inode, "es.es_len == 0");
2251 err = -EFSCORRUPTED;
2252 break;
2253 }
2254
2255 /*
2256 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2257 * we need to check next == EXT_MAX_BLOCKS because it is
2258 * possible that an extent is with unwritten and delayed
2259 * status due to when an extent is delayed allocated and
2260 * is allocated by fallocate status tree will track both of
2261 * them in a extent.
2262 *
2263 * So we could return a unwritten and delayed extent, and
2264 * its block is equal to 'next'.
2265 */
2266 if (next == next_del && next == EXT_MAX_BLOCKS) {
2267 flags |= FIEMAP_EXTENT_LAST;
2268 if (unlikely(next_del != EXT_MAX_BLOCKS ||
2269 next != EXT_MAX_BLOCKS)) {
2270 EXT4_ERROR_INODE(inode,
2271 "next extent == %u, next "
2272 "delalloc extent = %u",
2273 next, next_del);
2274 err = -EFSCORRUPTED;
2275 break;
2276 }
2277 }
2278
2279 if (exists) {
2280 err = fiemap_fill_next_extent(fieinfo,
2281 (__u64)es.es_lblk << blksize_bits,
2282 (__u64)es.es_pblk << blksize_bits,
2283 (__u64)es.es_len << blksize_bits,
2284 flags);
2285 if (err < 0)
2286 break;
2287 if (err == 1) {
2288 err = 0;
2289 break;
2290 }
2291 }
2292
2293 block = es.es_lblk + es.es_len;
2294 }
2295
2296 ext4_ext_drop_refs(path);
2297 kfree(path);
2298 return err;
2299}
2300
2301/*
2302 * ext4_ext_determine_hole - determine hole around given block
2303 * @inode: inode we lookup in
2304 * @path: path in extent tree to @lblk
2305 * @lblk: pointer to logical block around which we want to determine hole
2306 *
2307 * Determine hole length (and start if easily possible) around given logical
2308 * block. We don't try too hard to find the beginning of the hole but @path
2309 * actually points to extent before @lblk, we provide it.
2310 *
2311 * The function returns the length of a hole starting at @lblk. We update @lblk
2312 * to the beginning of the hole if we managed to find it.
2313 */
2314static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2315 struct ext4_ext_path *path,
2316 ext4_lblk_t *lblk)
2317{
2318 int depth = ext_depth(inode);
2319 struct ext4_extent *ex;
2320 ext4_lblk_t len;
2321
2322 ex = path[depth].p_ext;
2323 if (ex == NULL) {
2324 /* there is no extent yet, so gap is [0;-] */
2325 *lblk = 0;
2326 len = EXT_MAX_BLOCKS;
2327 } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2328 len = le32_to_cpu(ex->ee_block) - *lblk;
2329 } else if (*lblk >= le32_to_cpu(ex->ee_block)
2330 + ext4_ext_get_actual_len(ex)) {
2331 ext4_lblk_t next;
2332
2333 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2334 next = ext4_ext_next_allocated_block(path);
2335 BUG_ON(next == *lblk);
2336 len = next - *lblk;
2337 } else {
2338 BUG();
2339 }
2340 return len;
2341}
2342
2343/*
2344 * ext4_ext_put_gap_in_cache:
2345 * calculate boundaries of the gap that the requested block fits into
2346 * and cache this gap
2347 */
2348static void
2349ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2350 ext4_lblk_t hole_len)
2351{
2352 struct extent_status es;
2353
2354 ext4_es_find_delayed_extent_range(inode, hole_start,
2355 hole_start + hole_len - 1, &es);
2356 if (es.es_len) {
2357 /* There's delayed extent containing lblock? */
2358 if (es.es_lblk <= hole_start)
2359 return;
2360 hole_len = min(es.es_lblk - hole_start, hole_len);
2361 }
2362 ext_debug(" -> %u:%u\n", hole_start, hole_len);
2363 ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2364 EXTENT_STATUS_HOLE);
2365}
2366
2367/*
2368 * ext4_ext_rm_idx:
2369 * removes index from the index block.
2370 */
2371static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2372 struct ext4_ext_path *path, int depth)
2373{
2374 int err;
2375 ext4_fsblk_t leaf;
2376
2377 /* free index block */
2378 depth--;
2379 path = path + depth;
2380 leaf = ext4_idx_pblock(path->p_idx);
2381 if (unlikely(path->p_hdr->eh_entries == 0)) {
2382 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2383 return -EFSCORRUPTED;
2384 }
2385 err = ext4_ext_get_access(handle, inode, path);
2386 if (err)
2387 return err;
2388
2389 if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2390 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2391 len *= sizeof(struct ext4_extent_idx);
2392 memmove(path->p_idx, path->p_idx + 1, len);
2393 }
2394
2395 le16_add_cpu(&path->p_hdr->eh_entries, -1);
2396 err = ext4_ext_dirty(handle, inode, path);
2397 if (err)
2398 return err;
2399 ext_debug("index is empty, remove it, free block %llu\n", leaf);
2400 trace_ext4_ext_rm_idx(inode, leaf);
2401
2402 ext4_free_blocks(handle, inode, NULL, leaf, 1,
2403 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2404
2405 while (--depth >= 0) {
2406 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2407 break;
2408 path--;
2409 err = ext4_ext_get_access(handle, inode, path);
2410 if (err)
2411 break;
2412 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2413 err = ext4_ext_dirty(handle, inode, path);
2414 if (err)
2415 break;
2416 }
2417 return err;
2418}
2419
2420/*
2421 * ext4_ext_calc_credits_for_single_extent:
2422 * This routine returns max. credits that needed to insert an extent
2423 * to the extent tree.
2424 * When pass the actual path, the caller should calculate credits
2425 * under i_data_sem.
2426 */
2427int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2428 struct ext4_ext_path *path)
2429{
2430 if (path) {
2431 int depth = ext_depth(inode);
2432 int ret = 0;
2433
2434 /* probably there is space in leaf? */
2435 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2436 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2437
2438 /*
2439 * There are some space in the leaf tree, no
2440 * need to account for leaf block credit
2441 *
2442 * bitmaps and block group descriptor blocks
2443 * and other metadata blocks still need to be
2444 * accounted.
2445 */
2446 /* 1 bitmap, 1 block group descriptor */
2447 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2448 return ret;
2449 }
2450 }
2451
2452 return ext4_chunk_trans_blocks(inode, nrblocks);
2453}
2454
2455/*
2456 * How many index/leaf blocks need to change/allocate to add @extents extents?
2457 *
2458 * If we add a single extent, then in the worse case, each tree level
2459 * index/leaf need to be changed in case of the tree split.
2460 *
2461 * If more extents are inserted, they could cause the whole tree split more
2462 * than once, but this is really rare.
2463 */
2464int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2465{
2466 int index;
2467 int depth;
2468
2469 /* If we are converting the inline data, only one is needed here. */
2470 if (ext4_has_inline_data(inode))
2471 return 1;
2472
2473 depth = ext_depth(inode);
2474
2475 if (extents <= 1)
2476 index = depth * 2;
2477 else
2478 index = depth * 3;
2479
2480 return index;
2481}
2482
2483static inline int get_default_free_blocks_flags(struct inode *inode)
2484{
2485 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2486 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2487 else if (ext4_should_journal_data(inode))
2488 return EXT4_FREE_BLOCKS_FORGET;
2489 return 0;
2490}
2491
2492static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2493 struct ext4_extent *ex,
2494 long long *partial_cluster,
2495 ext4_lblk_t from, ext4_lblk_t to)
2496{
2497 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2498 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2499 ext4_fsblk_t pblk;
2500 int flags = get_default_free_blocks_flags(inode);
2501
2502 /*
2503 * For bigalloc file systems, we never free a partial cluster
2504 * at the beginning of the extent. Instead, we make a note
2505 * that we tried freeing the cluster, and check to see if we
2506 * need to free it on a subsequent call to ext4_remove_blocks,
2507 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2508 */
2509 flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2510
2511 trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2512 /*
2513 * If we have a partial cluster, and it's different from the
2514 * cluster of the last block, we need to explicitly free the
2515 * partial cluster here.
2516 */
2517 pblk = ext4_ext_pblock(ex) + ee_len - 1;
2518 if (*partial_cluster > 0 &&
2519 *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2520 ext4_free_blocks(handle, inode, NULL,
2521 EXT4_C2B(sbi, *partial_cluster),
2522 sbi->s_cluster_ratio, flags);
2523 *partial_cluster = 0;
2524 }
2525
2526#ifdef EXTENTS_STATS
2527 {
2528 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2529 spin_lock(&sbi->s_ext_stats_lock);
2530 sbi->s_ext_blocks += ee_len;
2531 sbi->s_ext_extents++;
2532 if (ee_len < sbi->s_ext_min)
2533 sbi->s_ext_min = ee_len;
2534 if (ee_len > sbi->s_ext_max)
2535 sbi->s_ext_max = ee_len;
2536 if (ext_depth(inode) > sbi->s_depth_max)
2537 sbi->s_depth_max = ext_depth(inode);
2538 spin_unlock(&sbi->s_ext_stats_lock);
2539 }
2540#endif
2541 if (from >= le32_to_cpu(ex->ee_block)
2542 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2543 /* tail removal */
2544 ext4_lblk_t num;
2545 long long first_cluster;
2546
2547 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2548 pblk = ext4_ext_pblock(ex) + ee_len - num;
2549 /*
2550 * Usually we want to free partial cluster at the end of the
2551 * extent, except for the situation when the cluster is still
2552 * used by any other extent (partial_cluster is negative).
2553 */
2554 if (*partial_cluster < 0 &&
2555 *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))
2556 flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2557
2558 ext_debug("free last %u blocks starting %llu partial %lld\n",
2559 num, pblk, *partial_cluster);
2560 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2561 /*
2562 * If the block range to be freed didn't start at the
2563 * beginning of a cluster, and we removed the entire
2564 * extent and the cluster is not used by any other extent,
2565 * save the partial cluster here, since we might need to
2566 * delete if we determine that the truncate or punch hole
2567 * operation has removed all of the blocks in the cluster.
2568 * If that cluster is used by another extent, preserve its
2569 * negative value so it isn't freed later on.
2570 *
2571 * If the whole extent wasn't freed, we've reached the
2572 * start of the truncated/punched region and have finished
2573 * removing blocks. If there's a partial cluster here it's
2574 * shared with the remainder of the extent and is no longer
2575 * a candidate for removal.
2576 */
2577 if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {
2578 first_cluster = (long long) EXT4_B2C(sbi, pblk);
2579 if (first_cluster != -*partial_cluster)
2580 *partial_cluster = first_cluster;
2581 } else {
2582 *partial_cluster = 0;
2583 }
2584 } else
2585 ext4_error(sbi->s_sb, "strange request: removal(2) "
2586 "%u-%u from %u:%u\n",
2587 from, to, le32_to_cpu(ex->ee_block), ee_len);
2588 return 0;
2589}
2590
2591
2592/*
2593 * ext4_ext_rm_leaf() Removes the extents associated with the
2594 * blocks appearing between "start" and "end". Both "start"
2595 * and "end" must appear in the same extent or EIO is returned.
2596 *
2597 * @handle: The journal handle
2598 * @inode: The files inode
2599 * @path: The path to the leaf
2600 * @partial_cluster: The cluster which we'll have to free if all extents
2601 * has been released from it. However, if this value is
2602 * negative, it's a cluster just to the right of the
2603 * punched region and it must not be freed.
2604 * @start: The first block to remove
2605 * @end: The last block to remove
2606 */
2607static int
2608ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2609 struct ext4_ext_path *path,
2610 long long *partial_cluster,
2611 ext4_lblk_t start, ext4_lblk_t end)
2612{
2613 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2614 int err = 0, correct_index = 0;
2615 int depth = ext_depth(inode), credits;
2616 struct ext4_extent_header *eh;
2617 ext4_lblk_t a, b;
2618 unsigned num;
2619 ext4_lblk_t ex_ee_block;
2620 unsigned short ex_ee_len;
2621 unsigned unwritten = 0;
2622 struct ext4_extent *ex;
2623 ext4_fsblk_t pblk;
2624
2625 /* the header must be checked already in ext4_ext_remove_space() */
2626 ext_debug("truncate since %u in leaf to %u\n", start, end);
2627 if (!path[depth].p_hdr)
2628 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2629 eh = path[depth].p_hdr;
2630 if (unlikely(path[depth].p_hdr == NULL)) {
2631 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2632 return -EFSCORRUPTED;
2633 }
2634 /* find where to start removing */
2635 ex = path[depth].p_ext;
2636 if (!ex)
2637 ex = EXT_LAST_EXTENT(eh);
2638
2639 ex_ee_block = le32_to_cpu(ex->ee_block);
2640 ex_ee_len = ext4_ext_get_actual_len(ex);
2641
2642 trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2643
2644 while (ex >= EXT_FIRST_EXTENT(eh) &&
2645 ex_ee_block + ex_ee_len > start) {
2646
2647 if (ext4_ext_is_unwritten(ex))
2648 unwritten = 1;
2649 else
2650 unwritten = 0;
2651
2652 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2653 unwritten, ex_ee_len);
2654 path[depth].p_ext = ex;
2655
2656 a = ex_ee_block > start ? ex_ee_block : start;
2657 b = ex_ee_block+ex_ee_len - 1 < end ?
2658 ex_ee_block+ex_ee_len - 1 : end;
2659
2660 ext_debug(" border %u:%u\n", a, b);
2661
2662 /* If this extent is beyond the end of the hole, skip it */
2663 if (end < ex_ee_block) {
2664 /*
2665 * We're going to skip this extent and move to another,
2666 * so note that its first cluster is in use to avoid
2667 * freeing it when removing blocks. Eventually, the
2668 * right edge of the truncated/punched region will
2669 * be just to the left.
2670 */
2671 if (sbi->s_cluster_ratio > 1) {
2672 pblk = ext4_ext_pblock(ex);
2673 *partial_cluster =
2674 -(long long) EXT4_B2C(sbi, pblk);
2675 }
2676 ex--;
2677 ex_ee_block = le32_to_cpu(ex->ee_block);
2678 ex_ee_len = ext4_ext_get_actual_len(ex);
2679 continue;
2680 } else if (b != ex_ee_block + ex_ee_len - 1) {
2681 EXT4_ERROR_INODE(inode,
2682 "can not handle truncate %u:%u "
2683 "on extent %u:%u",
2684 start, end, ex_ee_block,
2685 ex_ee_block + ex_ee_len - 1);
2686 err = -EFSCORRUPTED;
2687 goto out;
2688 } else if (a != ex_ee_block) {
2689 /* remove tail of the extent */
2690 num = a - ex_ee_block;
2691 } else {
2692 /* remove whole extent: excellent! */
2693 num = 0;
2694 }
2695 /*
2696 * 3 for leaf, sb, and inode plus 2 (bmap and group
2697 * descriptor) for each block group; assume two block
2698 * groups plus ex_ee_len/blocks_per_block_group for
2699 * the worst case
2700 */
2701 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2702 if (ex == EXT_FIRST_EXTENT(eh)) {
2703 correct_index = 1;
2704 credits += (ext_depth(inode)) + 1;
2705 }
2706 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2707
2708 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2709 if (err)
2710 goto out;
2711
2712 err = ext4_ext_get_access(handle, inode, path + depth);
2713 if (err)
2714 goto out;
2715
2716 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2717 a, b);
2718 if (err)
2719 goto out;
2720
2721 if (num == 0)
2722 /* this extent is removed; mark slot entirely unused */
2723 ext4_ext_store_pblock(ex, 0);
2724
2725 ex->ee_len = cpu_to_le16(num);
2726 /*
2727 * Do not mark unwritten if all the blocks in the
2728 * extent have been removed.
2729 */
2730 if (unwritten && num)
2731 ext4_ext_mark_unwritten(ex);
2732 /*
2733 * If the extent was completely released,
2734 * we need to remove it from the leaf
2735 */
2736 if (num == 0) {
2737 if (end != EXT_MAX_BLOCKS - 1) {
2738 /*
2739 * For hole punching, we need to scoot all the
2740 * extents up when an extent is removed so that
2741 * we dont have blank extents in the middle
2742 */
2743 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2744 sizeof(struct ext4_extent));
2745
2746 /* Now get rid of the one at the end */
2747 memset(EXT_LAST_EXTENT(eh), 0,
2748 sizeof(struct ext4_extent));
2749 }
2750 le16_add_cpu(&eh->eh_entries, -1);
2751 }
2752
2753 err = ext4_ext_dirty(handle, inode, path + depth);
2754 if (err)
2755 goto out;
2756
2757 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2758 ext4_ext_pblock(ex));
2759 ex--;
2760 ex_ee_block = le32_to_cpu(ex->ee_block);
2761 ex_ee_len = ext4_ext_get_actual_len(ex);
2762 }
2763
2764 if (correct_index && eh->eh_entries)
2765 err = ext4_ext_correct_indexes(handle, inode, path);
2766
2767 /*
2768 * If there's a partial cluster and at least one extent remains in
2769 * the leaf, free the partial cluster if it isn't shared with the
2770 * current extent. If it is shared with the current extent
2771 * we zero partial_cluster because we've reached the start of the
2772 * truncated/punched region and we're done removing blocks.
2773 */
2774 if (*partial_cluster > 0 && ex >= EXT_FIRST_EXTENT(eh)) {
2775 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2776 if (*partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {
2777 ext4_free_blocks(handle, inode, NULL,
2778 EXT4_C2B(sbi, *partial_cluster),
2779 sbi->s_cluster_ratio,
2780 get_default_free_blocks_flags(inode));
2781 }
2782 *partial_cluster = 0;
2783 }
2784
2785 /* if this leaf is free, then we should
2786 * remove it from index block above */
2787 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2788 err = ext4_ext_rm_idx(handle, inode, path, depth);
2789
2790out:
2791 return err;
2792}
2793
2794/*
2795 * ext4_ext_more_to_rm:
2796 * returns 1 if current index has to be freed (even partial)
2797 */
2798static int
2799ext4_ext_more_to_rm(struct ext4_ext_path *path)
2800{
2801 BUG_ON(path->p_idx == NULL);
2802
2803 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2804 return 0;
2805
2806 /*
2807 * if truncate on deeper level happened, it wasn't partial,
2808 * so we have to consider current index for truncation
2809 */
2810 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2811 return 0;
2812 return 1;
2813}
2814
2815int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2816 ext4_lblk_t end)
2817{
2818 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2819 int depth = ext_depth(inode);
2820 struct ext4_ext_path *path = NULL;
2821 long long partial_cluster = 0;
2822 handle_t *handle;
2823 int i = 0, err = 0;
2824
2825 ext_debug("truncate since %u to %u\n", start, end);
2826
2827 /* probably first extent we're gonna free will be last in block */
2828 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2829 if (IS_ERR(handle))
2830 return PTR_ERR(handle);
2831
2832again:
2833 trace_ext4_ext_remove_space(inode, start, end, depth);
2834
2835 /*
2836 * Check if we are removing extents inside the extent tree. If that
2837 * is the case, we are going to punch a hole inside the extent tree
2838 * so we have to check whether we need to split the extent covering
2839 * the last block to remove so we can easily remove the part of it
2840 * in ext4_ext_rm_leaf().
2841 */
2842 if (end < EXT_MAX_BLOCKS - 1) {
2843 struct ext4_extent *ex;
2844 ext4_lblk_t ee_block, ex_end, lblk;
2845 ext4_fsblk_t pblk;
2846
2847 /* find extent for or closest extent to this block */
2848 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2849 if (IS_ERR(path)) {
2850 ext4_journal_stop(handle);
2851 return PTR_ERR(path);
2852 }
2853 depth = ext_depth(inode);
2854 /* Leaf not may not exist only if inode has no blocks at all */
2855 ex = path[depth].p_ext;
2856 if (!ex) {
2857 if (depth) {
2858 EXT4_ERROR_INODE(inode,
2859 "path[%d].p_hdr == NULL",
2860 depth);
2861 err = -EFSCORRUPTED;
2862 }
2863 goto out;
2864 }
2865
2866 ee_block = le32_to_cpu(ex->ee_block);
2867 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2868
2869 /*
2870 * See if the last block is inside the extent, if so split
2871 * the extent at 'end' block so we can easily remove the
2872 * tail of the first part of the split extent in
2873 * ext4_ext_rm_leaf().
2874 */
2875 if (end >= ee_block && end < ex_end) {
2876
2877 /*
2878 * If we're going to split the extent, note that
2879 * the cluster containing the block after 'end' is
2880 * in use to avoid freeing it when removing blocks.
2881 */
2882 if (sbi->s_cluster_ratio > 1) {
2883 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2884 partial_cluster =
2885 -(long long) EXT4_B2C(sbi, pblk);
2886 }
2887
2888 /*
2889 * Split the extent in two so that 'end' is the last
2890 * block in the first new extent. Also we should not
2891 * fail removing space due to ENOSPC so try to use
2892 * reserved block if that happens.
2893 */
2894 err = ext4_force_split_extent_at(handle, inode, &path,
2895 end + 1, 1);
2896 if (err < 0)
2897 goto out;
2898
2899 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end) {
2900 /*
2901 * If there's an extent to the right its first cluster
2902 * contains the immediate right boundary of the
2903 * truncated/punched region. Set partial_cluster to
2904 * its negative value so it won't be freed if shared
2905 * with the current extent. The end < ee_block case
2906 * is handled in ext4_ext_rm_leaf().
2907 */
2908 lblk = ex_end + 1;
2909 err = ext4_ext_search_right(inode, path, &lblk, &pblk,
2910 &ex);
2911 if (err)
2912 goto out;
2913 if (pblk)
2914 partial_cluster =
2915 -(long long) EXT4_B2C(sbi, pblk);
2916 }
2917 }
2918 /*
2919 * We start scanning from right side, freeing all the blocks
2920 * after i_size and walking into the tree depth-wise.
2921 */
2922 depth = ext_depth(inode);
2923 if (path) {
2924 int k = i = depth;
2925 while (--k > 0)
2926 path[k].p_block =
2927 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2928 } else {
2929 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2930 GFP_NOFS);
2931 if (path == NULL) {
2932 ext4_journal_stop(handle);
2933 return -ENOMEM;
2934 }
2935 path[0].p_maxdepth = path[0].p_depth = depth;
2936 path[0].p_hdr = ext_inode_hdr(inode);
2937 i = 0;
2938
2939 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2940 err = -EFSCORRUPTED;
2941 goto out;
2942 }
2943 }
2944 err = 0;
2945
2946 while (i >= 0 && err == 0) {
2947 if (i == depth) {
2948 /* this is leaf block */
2949 err = ext4_ext_rm_leaf(handle, inode, path,
2950 &partial_cluster, start,
2951 end);
2952 /* root level has p_bh == NULL, brelse() eats this */
2953 brelse(path[i].p_bh);
2954 path[i].p_bh = NULL;
2955 i--;
2956 continue;
2957 }
2958
2959 /* this is index block */
2960 if (!path[i].p_hdr) {
2961 ext_debug("initialize header\n");
2962 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2963 }
2964
2965 if (!path[i].p_idx) {
2966 /* this level hasn't been touched yet */
2967 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2968 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2969 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2970 path[i].p_hdr,
2971 le16_to_cpu(path[i].p_hdr->eh_entries));
2972 } else {
2973 /* we were already here, see at next index */
2974 path[i].p_idx--;
2975 }
2976
2977 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2978 i, EXT_FIRST_INDEX(path[i].p_hdr),
2979 path[i].p_idx);
2980 if (ext4_ext_more_to_rm(path + i)) {
2981 struct buffer_head *bh;
2982 /* go to the next level */
2983 ext_debug("move to level %d (block %llu)\n",
2984 i + 1, ext4_idx_pblock(path[i].p_idx));
2985 memset(path + i + 1, 0, sizeof(*path));
2986 bh = read_extent_tree_block(inode,
2987 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2988 EXT4_EX_NOCACHE);
2989 if (IS_ERR(bh)) {
2990 /* should we reset i_size? */
2991 err = PTR_ERR(bh);
2992 break;
2993 }
2994 /* Yield here to deal with large extent trees.
2995 * Should be a no-op if we did IO above. */
2996 cond_resched();
2997 if (WARN_ON(i + 1 > depth)) {
2998 err = -EFSCORRUPTED;
2999 break;
3000 }
3001 path[i + 1].p_bh = bh;
3002
3003 /* save actual number of indexes since this
3004 * number is changed at the next iteration */
3005 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3006 i++;
3007 } else {
3008 /* we finished processing this index, go up */
3009 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3010 /* index is empty, remove it;
3011 * handle must be already prepared by the
3012 * truncatei_leaf() */
3013 err = ext4_ext_rm_idx(handle, inode, path, i);
3014 }
3015 /* root level has p_bh == NULL, brelse() eats this */
3016 brelse(path[i].p_bh);
3017 path[i].p_bh = NULL;
3018 i--;
3019 ext_debug("return to level %d\n", i);
3020 }
3021 }
3022
3023 trace_ext4_ext_remove_space_done(inode, start, end, depth,
3024 partial_cluster, path->p_hdr->eh_entries);
3025
3026 /*
3027 * If we still have something in the partial cluster and we have removed
3028 * even the first extent, then we should free the blocks in the partial
3029 * cluster as well. (This code will only run when there are no leaves
3030 * to the immediate left of the truncated/punched region.)
3031 */
3032 if (partial_cluster > 0 && err == 0) {
3033 /* don't zero partial_cluster since it's not used afterwards */
3034 ext4_free_blocks(handle, inode, NULL,
3035 EXT4_C2B(sbi, partial_cluster),
3036 sbi->s_cluster_ratio,
3037 get_default_free_blocks_flags(inode));
3038 }
3039
3040 /* TODO: flexible tree reduction should be here */
3041 if (path->p_hdr->eh_entries == 0) {
3042 /*
3043 * truncate to zero freed all the tree,
3044 * so we need to correct eh_depth
3045 */
3046 err = ext4_ext_get_access(handle, inode, path);
3047 if (err == 0) {
3048 ext_inode_hdr(inode)->eh_depth = 0;
3049 ext_inode_hdr(inode)->eh_max =
3050 cpu_to_le16(ext4_ext_space_root(inode, 0));
3051 err = ext4_ext_dirty(handle, inode, path);
3052 }
3053 }
3054out:
3055 ext4_ext_drop_refs(path);
3056 kfree(path);
3057 path = NULL;
3058 if (err == -EAGAIN)
3059 goto again;
3060 ext4_journal_stop(handle);
3061
3062 return err;
3063}
3064
3065/*
3066 * called at mount time
3067 */
3068void ext4_ext_init(struct super_block *sb)
3069{
3070 /*
3071 * possible initialization would be here
3072 */
3073
3074 if (ext4_has_feature_extents(sb)) {
3075#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3076 printk(KERN_INFO "EXT4-fs: file extents enabled"
3077#ifdef AGGRESSIVE_TEST
3078 ", aggressive tests"
3079#endif
3080#ifdef CHECK_BINSEARCH
3081 ", check binsearch"
3082#endif
3083#ifdef EXTENTS_STATS
3084 ", stats"
3085#endif
3086 "\n");
3087#endif
3088#ifdef EXTENTS_STATS
3089 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3090 EXT4_SB(sb)->s_ext_min = 1 << 30;
3091 EXT4_SB(sb)->s_ext_max = 0;
3092#endif
3093 }
3094}
3095
3096/*
3097 * called at umount time
3098 */
3099void ext4_ext_release(struct super_block *sb)
3100{
3101 if (!ext4_has_feature_extents(sb))
3102 return;
3103
3104#ifdef EXTENTS_STATS
3105 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3106 struct ext4_sb_info *sbi = EXT4_SB(sb);
3107 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3108 sbi->s_ext_blocks, sbi->s_ext_extents,
3109 sbi->s_ext_blocks / sbi->s_ext_extents);
3110 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3111 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3112 }
3113#endif
3114}
3115
3116static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3117{
3118 ext4_lblk_t ee_block;
3119 ext4_fsblk_t ee_pblock;
3120 unsigned int ee_len;
3121
3122 ee_block = le32_to_cpu(ex->ee_block);
3123 ee_len = ext4_ext_get_actual_len(ex);
3124 ee_pblock = ext4_ext_pblock(ex);
3125
3126 if (ee_len == 0)
3127 return 0;
3128
3129 return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3130 EXTENT_STATUS_WRITTEN);
3131}
3132
3133/* FIXME!! we need to try to merge to left or right after zero-out */
3134static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3135{
3136 ext4_fsblk_t ee_pblock;
3137 unsigned int ee_len;
3138
3139 ee_len = ext4_ext_get_actual_len(ex);
3140 ee_pblock = ext4_ext_pblock(ex);
3141 return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3142 ee_len);
3143}
3144
3145/*
3146 * ext4_split_extent_at() splits an extent at given block.
3147 *
3148 * @handle: the journal handle
3149 * @inode: the file inode
3150 * @path: the path to the extent
3151 * @split: the logical block where the extent is splitted.
3152 * @split_flags: indicates if the extent could be zeroout if split fails, and
3153 * the states(init or unwritten) of new extents.
3154 * @flags: flags used to insert new extent to extent tree.
3155 *
3156 *
3157 * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3158 * of which are deterimined by split_flag.
3159 *
3160 * There are two cases:
3161 * a> the extent are splitted into two extent.
3162 * b> split is not needed, and just mark the extent.
3163 *
3164 * return 0 on success.
3165 */
3166static int ext4_split_extent_at(handle_t *handle,
3167 struct inode *inode,
3168 struct ext4_ext_path **ppath,
3169 ext4_lblk_t split,
3170 int split_flag,
3171 int flags)
3172{
3173 struct ext4_ext_path *path = *ppath;
3174 ext4_fsblk_t newblock;
3175 ext4_lblk_t ee_block;
3176 struct ext4_extent *ex, newex, orig_ex, zero_ex;
3177 struct ext4_extent *ex2 = NULL;
3178 unsigned int ee_len, depth;
3179 int err = 0;
3180
3181 BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3182 (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3183
3184 ext_debug("ext4_split_extents_at: inode %lu, logical"
3185 "block %llu\n", inode->i_ino, (unsigned long long)split);
3186
3187 ext4_ext_show_leaf(inode, path);
3188
3189 depth = ext_depth(inode);
3190 ex = path[depth].p_ext;
3191 ee_block = le32_to_cpu(ex->ee_block);
3192 ee_len = ext4_ext_get_actual_len(ex);
3193 newblock = split - ee_block + ext4_ext_pblock(ex);
3194
3195 BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3196 BUG_ON(!ext4_ext_is_unwritten(ex) &&
3197 split_flag & (EXT4_EXT_MAY_ZEROOUT |
3198 EXT4_EXT_MARK_UNWRIT1 |
3199 EXT4_EXT_MARK_UNWRIT2));
3200
3201 err = ext4_ext_get_access(handle, inode, path + depth);
3202 if (err)
3203 goto out;
3204
3205 if (split == ee_block) {
3206 /*
3207 * case b: block @split is the block that the extent begins with
3208 * then we just change the state of the extent, and splitting
3209 * is not needed.
3210 */
3211 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3212 ext4_ext_mark_unwritten(ex);
3213 else
3214 ext4_ext_mark_initialized(ex);
3215
3216 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3217 ext4_ext_try_to_merge(handle, inode, path, ex);
3218
3219 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3220 goto out;
3221 }
3222
3223 /* case a */
3224 memcpy(&orig_ex, ex, sizeof(orig_ex));
3225 ex->ee_len = cpu_to_le16(split - ee_block);
3226 if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3227 ext4_ext_mark_unwritten(ex);
3228
3229 /*
3230 * path may lead to new leaf, not to original leaf any more
3231 * after ext4_ext_insert_extent() returns,
3232 */
3233 err = ext4_ext_dirty(handle, inode, path + depth);
3234 if (err)
3235 goto fix_extent_len;
3236
3237 ex2 = &newex;
3238 ex2->ee_block = cpu_to_le32(split);
3239 ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
3240 ext4_ext_store_pblock(ex2, newblock);
3241 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3242 ext4_ext_mark_unwritten(ex2);
3243
3244 err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3245 if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3246 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3247 if (split_flag & EXT4_EXT_DATA_VALID1) {
3248 err = ext4_ext_zeroout(inode, ex2);
3249 zero_ex.ee_block = ex2->ee_block;
3250 zero_ex.ee_len = cpu_to_le16(
3251 ext4_ext_get_actual_len(ex2));
3252 ext4_ext_store_pblock(&zero_ex,
3253 ext4_ext_pblock(ex2));
3254 } else {
3255 err = ext4_ext_zeroout(inode, ex);
3256 zero_ex.ee_block = ex->ee_block;
3257 zero_ex.ee_len = cpu_to_le16(
3258 ext4_ext_get_actual_len(ex));
3259 ext4_ext_store_pblock(&zero_ex,
3260 ext4_ext_pblock(ex));
3261 }
3262 } else {
3263 err = ext4_ext_zeroout(inode, &orig_ex);
3264 zero_ex.ee_block = orig_ex.ee_block;
3265 zero_ex.ee_len = cpu_to_le16(
3266 ext4_ext_get_actual_len(&orig_ex));
3267 ext4_ext_store_pblock(&zero_ex,
3268 ext4_ext_pblock(&orig_ex));
3269 }
3270
3271 if (err)
3272 goto fix_extent_len;
3273 /* update the extent length and mark as initialized */
3274 ex->ee_len = cpu_to_le16(ee_len);
3275 ext4_ext_try_to_merge(handle, inode, path, ex);
3276 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3277 if (err)
3278 goto fix_extent_len;
3279
3280 /* update extent status tree */
3281 err = ext4_zeroout_es(inode, &zero_ex);
3282
3283 goto out;
3284 } else if (err)
3285 goto fix_extent_len;
3286
3287out:
3288 ext4_ext_show_leaf(inode, path);
3289 return err;
3290
3291fix_extent_len:
3292 ex->ee_len = orig_ex.ee_len;
3293 ext4_ext_dirty(handle, inode, path + path->p_depth);
3294 return err;
3295}
3296
3297/*
3298 * ext4_split_extents() splits an extent and mark extent which is covered
3299 * by @map as split_flags indicates
3300 *
3301 * It may result in splitting the extent into multiple extents (up to three)
3302 * There are three possibilities:
3303 * a> There is no split required
3304 * b> Splits in two extents: Split is happening at either end of the extent
3305 * c> Splits in three extents: Somone is splitting in middle of the extent
3306 *
3307 */
3308static int ext4_split_extent(handle_t *handle,
3309 struct inode *inode,
3310 struct ext4_ext_path **ppath,
3311 struct ext4_map_blocks *map,
3312 int split_flag,
3313 int flags)
3314{
3315 struct ext4_ext_path *path = *ppath;
3316 ext4_lblk_t ee_block;
3317 struct ext4_extent *ex;
3318 unsigned int ee_len, depth;
3319 int err = 0;
3320 int unwritten;
3321 int split_flag1, flags1;
3322 int allocated = map->m_len;
3323
3324 depth = ext_depth(inode);
3325 ex = path[depth].p_ext;
3326 ee_block = le32_to_cpu(ex->ee_block);
3327 ee_len = ext4_ext_get_actual_len(ex);
3328 unwritten = ext4_ext_is_unwritten(ex);
3329
3330 if (map->m_lblk + map->m_len < ee_block + ee_len) {
3331 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3332 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3333 if (unwritten)
3334 split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3335 EXT4_EXT_MARK_UNWRIT2;
3336 if (split_flag & EXT4_EXT_DATA_VALID2)
3337 split_flag1 |= EXT4_EXT_DATA_VALID1;
3338 err = ext4_split_extent_at(handle, inode, ppath,
3339 map->m_lblk + map->m_len, split_flag1, flags1);
3340 if (err)
3341 goto out;
3342 } else {
3343 allocated = ee_len - (map->m_lblk - ee_block);
3344 }
3345 /*
3346 * Update path is required because previous ext4_split_extent_at() may
3347 * result in split of original leaf or extent zeroout.
3348 */
3349 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3350 if (IS_ERR(path))
3351 return PTR_ERR(path);
3352 depth = ext_depth(inode);
3353 ex = path[depth].p_ext;
3354 if (!ex) {
3355 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3356 (unsigned long) map->m_lblk);
3357 return -EFSCORRUPTED;
3358 }
3359 unwritten = ext4_ext_is_unwritten(ex);
3360 split_flag1 = 0;
3361
3362 if (map->m_lblk >= ee_block) {
3363 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3364 if (unwritten) {
3365 split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3366 split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3367 EXT4_EXT_MARK_UNWRIT2);
3368 }
3369 err = ext4_split_extent_at(handle, inode, ppath,
3370 map->m_lblk, split_flag1, flags);
3371 if (err)
3372 goto out;
3373 }
3374
3375 ext4_ext_show_leaf(inode, path);
3376out:
3377 return err ? err : allocated;
3378}
3379
3380/*
3381 * This function is called by ext4_ext_map_blocks() if someone tries to write
3382 * to an unwritten extent. It may result in splitting the unwritten
3383 * extent into multiple extents (up to three - one initialized and two
3384 * unwritten).
3385 * There are three possibilities:
3386 * a> There is no split required: Entire extent should be initialized
3387 * b> Splits in two extents: Write is happening at either end of the extent
3388 * c> Splits in three extents: Somone is writing in middle of the extent
3389 *
3390 * Pre-conditions:
3391 * - The extent pointed to by 'path' is unwritten.
3392 * - The extent pointed to by 'path' contains a superset
3393 * of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3394 *
3395 * Post-conditions on success:
3396 * - the returned value is the number of blocks beyond map->l_lblk
3397 * that are allocated and initialized.
3398 * It is guaranteed to be >= map->m_len.
3399 */
3400static int ext4_ext_convert_to_initialized(handle_t *handle,
3401 struct inode *inode,
3402 struct ext4_map_blocks *map,
3403 struct ext4_ext_path **ppath,
3404 int flags)
3405{
3406 struct ext4_ext_path *path = *ppath;
3407 struct ext4_sb_info *sbi;
3408 struct ext4_extent_header *eh;
3409 struct ext4_map_blocks split_map;
3410 struct ext4_extent zero_ex;
3411 struct ext4_extent *ex, *abut_ex;
3412 ext4_lblk_t ee_block, eof_block;
3413 unsigned int ee_len, depth, map_len = map->m_len;
3414 int allocated = 0, max_zeroout = 0;
3415 int err = 0;
3416 int split_flag = 0;
3417
3418 ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3419 "block %llu, max_blocks %u\n", inode->i_ino,
3420 (unsigned long long)map->m_lblk, map_len);
3421
3422 sbi = EXT4_SB(inode->i_sb);
3423 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3424 inode->i_sb->s_blocksize_bits;
3425 if (eof_block < map->m_lblk + map_len)
3426 eof_block = map->m_lblk + map_len;
3427
3428 depth = ext_depth(inode);
3429 eh = path[depth].p_hdr;
3430 ex = path[depth].p_ext;
3431 ee_block = le32_to_cpu(ex->ee_block);
3432 ee_len = ext4_ext_get_actual_len(ex);
3433 zero_ex.ee_len = 0;
3434
3435 trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3436
3437 /* Pre-conditions */
3438 BUG_ON(!ext4_ext_is_unwritten(ex));
3439 BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3440
3441 /*
3442 * Attempt to transfer newly initialized blocks from the currently
3443 * unwritten extent to its neighbor. This is much cheaper
3444 * than an insertion followed by a merge as those involve costly
3445 * memmove() calls. Transferring to the left is the common case in
3446 * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3447 * followed by append writes.
3448 *
3449 * Limitations of the current logic:
3450 * - L1: we do not deal with writes covering the whole extent.
3451 * This would require removing the extent if the transfer
3452 * is possible.
3453 * - L2: we only attempt to merge with an extent stored in the
3454 * same extent tree node.
3455 */
3456 if ((map->m_lblk == ee_block) &&
3457 /* See if we can merge left */
3458 (map_len < ee_len) && /*L1*/
3459 (ex > EXT_FIRST_EXTENT(eh))) { /*L2*/
3460 ext4_lblk_t prev_lblk;
3461 ext4_fsblk_t prev_pblk, ee_pblk;
3462 unsigned int prev_len;
3463
3464 abut_ex = ex - 1;
3465 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3466 prev_len = ext4_ext_get_actual_len(abut_ex);
3467 prev_pblk = ext4_ext_pblock(abut_ex);
3468 ee_pblk = ext4_ext_pblock(ex);
3469
3470 /*
3471 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3472 * upon those conditions:
3473 * - C1: abut_ex is initialized,
3474 * - C2: abut_ex is logically abutting ex,
3475 * - C3: abut_ex is physically abutting ex,
3476 * - C4: abut_ex can receive the additional blocks without
3477 * overflowing the (initialized) length limit.
3478 */
3479 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3480 ((prev_lblk + prev_len) == ee_block) && /*C2*/
3481 ((prev_pblk + prev_len) == ee_pblk) && /*C3*/
3482 (prev_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3483 err = ext4_ext_get_access(handle, inode, path + depth);
3484 if (err)
3485 goto out;
3486
3487 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3488 map, ex, abut_ex);
3489
3490 /* Shift the start of ex by 'map_len' blocks */
3491 ex->ee_block = cpu_to_le32(ee_block + map_len);
3492 ext4_ext_store_pblock(ex, ee_pblk + map_len);
3493 ex->ee_len = cpu_to_le16(ee_len - map_len);
3494 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3495
3496 /* Extend abut_ex by 'map_len' blocks */
3497 abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3498
3499 /* Result: number of initialized blocks past m_lblk */
3500 allocated = map_len;
3501 }
3502 } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3503 (map_len < ee_len) && /*L1*/
3504 ex < EXT_LAST_EXTENT(eh)) { /*L2*/
3505 /* See if we can merge right */
3506 ext4_lblk_t next_lblk;
3507 ext4_fsblk_t next_pblk, ee_pblk;
3508 unsigned int next_len;
3509
3510 abut_ex = ex + 1;
3511 next_lblk = le32_to_cpu(abut_ex->ee_block);
3512 next_len = ext4_ext_get_actual_len(abut_ex);
3513 next_pblk = ext4_ext_pblock(abut_ex);
3514 ee_pblk = ext4_ext_pblock(ex);
3515
3516 /*
3517 * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3518 * upon those conditions:
3519 * - C1: abut_ex is initialized,
3520 * - C2: abut_ex is logically abutting ex,
3521 * - C3: abut_ex is physically abutting ex,
3522 * - C4: abut_ex can receive the additional blocks without
3523 * overflowing the (initialized) length limit.
3524 */
3525 if ((!ext4_ext_is_unwritten(abut_ex)) && /*C1*/
3526 ((map->m_lblk + map_len) == next_lblk) && /*C2*/
3527 ((ee_pblk + ee_len) == next_pblk) && /*C3*/
3528 (next_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
3529 err = ext4_ext_get_access(handle, inode, path + depth);
3530 if (err)
3531 goto out;
3532
3533 trace_ext4_ext_convert_to_initialized_fastpath(inode,
3534 map, ex, abut_ex);
3535
3536 /* Shift the start of abut_ex by 'map_len' blocks */
3537 abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3538 ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3539 ex->ee_len = cpu_to_le16(ee_len - map_len);
3540 ext4_ext_mark_unwritten(ex); /* Restore the flag */
3541
3542 /* Extend abut_ex by 'map_len' blocks */
3543 abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3544
3545 /* Result: number of initialized blocks past m_lblk */
3546 allocated = map_len;
3547 }
3548 }
3549 if (allocated) {
3550 /* Mark the block containing both extents as dirty */
3551 ext4_ext_dirty(handle, inode, path + depth);
3552
3553 /* Update path to point to the right extent */
3554 path[depth].p_ext = abut_ex;
3555 goto out;
3556 } else
3557 allocated = ee_len - (map->m_lblk - ee_block);
3558
3559 WARN_ON(map->m_lblk < ee_block);
3560 /*
3561 * It is safe to convert extent to initialized via explicit
3562 * zeroout only if extent is fully inside i_size or new_size.
3563 */
3564 split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3565
3566 if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3567 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3568 (inode->i_sb->s_blocksize_bits - 10);
3569
3570 if (ext4_encrypted_inode(inode))
3571 max_zeroout = 0;
3572
3573 /* If extent is less than s_max_zeroout_kb, zeroout directly */
3574 if (max_zeroout && (ee_len <= max_zeroout)) {
3575 err = ext4_ext_zeroout(inode, ex);
3576 if (err)
3577 goto out;
3578 zero_ex.ee_block = ex->ee_block;
3579 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3580 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3581
3582 err = ext4_ext_get_access(handle, inode, path + depth);
3583 if (err)
3584 goto out;
3585 ext4_ext_mark_initialized(ex);
3586 ext4_ext_try_to_merge(handle, inode, path, ex);
3587 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3588 goto out;
3589 }
3590
3591 /*
3592 * four cases:
3593 * 1. split the extent into three extents.
3594 * 2. split the extent into two extents, zeroout the first half.
3595 * 3. split the extent into two extents, zeroout the second half.
3596 * 4. split the extent into two extents with out zeroout.
3597 */
3598 split_map.m_lblk = map->m_lblk;
3599 split_map.m_len = map->m_len;
3600
3601 if (max_zeroout && (allocated > map->m_len)) {
3602 if (allocated <= max_zeroout) {
3603 /* case 3 */
3604 zero_ex.ee_block =
3605 cpu_to_le32(map->m_lblk);
3606 zero_ex.ee_len = cpu_to_le16(allocated);
3607 ext4_ext_store_pblock(&zero_ex,
3608 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3609 err = ext4_ext_zeroout(inode, &zero_ex);
3610 if (err)
3611 goto out;
3612 split_map.m_lblk = map->m_lblk;
3613 split_map.m_len = allocated;
3614 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3615 /* case 2 */
3616 if (map->m_lblk != ee_block) {
3617 zero_ex.ee_block = ex->ee_block;
3618 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3619 ee_block);
3620 ext4_ext_store_pblock(&zero_ex,
3621 ext4_ext_pblock(ex));
3622 err = ext4_ext_zeroout(inode, &zero_ex);
3623 if (err)
3624 goto out;
3625 }
3626
3627 split_map.m_lblk = ee_block;
3628 split_map.m_len = map->m_lblk - ee_block + map->m_len;
3629 allocated = map->m_len;
3630 }
3631 }
3632
3633 err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3634 flags);
3635 if (err > 0)
3636 err = 0;
3637out:
3638 /* If we have gotten a failure, don't zero out status tree */
3639 if (!err)
3640 err = ext4_zeroout_es(inode, &zero_ex);
3641 return err ? err : allocated;
3642}
3643
3644/*
3645 * This function is called by ext4_ext_map_blocks() from
3646 * ext4_get_blocks_dio_write() when DIO to write
3647 * to an unwritten extent.
3648 *
3649 * Writing to an unwritten extent may result in splitting the unwritten
3650 * extent into multiple initialized/unwritten extents (up to three)
3651 * There are three possibilities:
3652 * a> There is no split required: Entire extent should be unwritten
3653 * b> Splits in two extents: Write is happening at either end of the extent
3654 * c> Splits in three extents: Somone is writing in middle of the extent
3655 *
3656 * This works the same way in the case of initialized -> unwritten conversion.
3657 *
3658 * One of more index blocks maybe needed if the extent tree grow after
3659 * the unwritten extent split. To prevent ENOSPC occur at the IO
3660 * complete, we need to split the unwritten extent before DIO submit
3661 * the IO. The unwritten extent called at this time will be split
3662 * into three unwritten extent(at most). After IO complete, the part
3663 * being filled will be convert to initialized by the end_io callback function
3664 * via ext4_convert_unwritten_extents().
3665 *
3666 * Returns the size of unwritten extent to be written on success.
3667 */
3668static int ext4_split_convert_extents(handle_t *handle,
3669 struct inode *inode,
3670 struct ext4_map_blocks *map,
3671 struct ext4_ext_path **ppath,
3672 int flags)
3673{
3674 struct ext4_ext_path *path = *ppath;
3675 ext4_lblk_t eof_block;
3676 ext4_lblk_t ee_block;
3677 struct ext4_extent *ex;
3678 unsigned int ee_len;
3679 int split_flag = 0, depth;
3680
3681 ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3682 __func__, inode->i_ino,
3683 (unsigned long long)map->m_lblk, map->m_len);
3684
3685 eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3686 inode->i_sb->s_blocksize_bits;
3687 if (eof_block < map->m_lblk + map->m_len)
3688 eof_block = map->m_lblk + map->m_len;
3689 /*
3690 * It is safe to convert extent to initialized via explicit
3691 * zeroout only if extent is fully insde i_size or new_size.
3692 */
3693 depth = ext_depth(inode);
3694 ex = path[depth].p_ext;
3695 ee_block = le32_to_cpu(ex->ee_block);
3696 ee_len = ext4_ext_get_actual_len(ex);
3697
3698 /* Convert to unwritten */
3699 if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3700 split_flag |= EXT4_EXT_DATA_VALID1;
3701 /* Convert to initialized */
3702 } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3703 split_flag |= ee_block + ee_len <= eof_block ?
3704 EXT4_EXT_MAY_ZEROOUT : 0;
3705 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3706 }
3707 flags |= EXT4_GET_BLOCKS_PRE_IO;
3708 return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3709}
3710
3711static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3712 struct inode *inode,
3713 struct ext4_map_blocks *map,
3714 struct ext4_ext_path **ppath)
3715{
3716 struct ext4_ext_path *path = *ppath;
3717 struct ext4_extent *ex;
3718 ext4_lblk_t ee_block;
3719 unsigned int ee_len;
3720 int depth;
3721 int err = 0;
3722
3723 depth = ext_depth(inode);
3724 ex = path[depth].p_ext;
3725 ee_block = le32_to_cpu(ex->ee_block);
3726 ee_len = ext4_ext_get_actual_len(ex);
3727
3728 ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3729 "block %llu, max_blocks %u\n", inode->i_ino,
3730 (unsigned long long)ee_block, ee_len);
3731
3732 /* If extent is larger than requested it is a clear sign that we still
3733 * have some extent state machine issues left. So extent_split is still
3734 * required.
3735 * TODO: Once all related issues will be fixed this situation should be
3736 * illegal.
3737 */
3738 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3739#ifdef EXT4_DEBUG
3740 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3741 " len %u; IO logical block %llu, len %u\n",
3742 inode->i_ino, (unsigned long long)ee_block, ee_len,
3743 (unsigned long long)map->m_lblk, map->m_len);
3744#endif
3745 err = ext4_split_convert_extents(handle, inode, map, ppath,
3746 EXT4_GET_BLOCKS_CONVERT);
3747 if (err < 0)
3748 return err;
3749 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3750 if (IS_ERR(path))
3751 return PTR_ERR(path);
3752 depth = ext_depth(inode);
3753 ex = path[depth].p_ext;
3754 }
3755
3756 err = ext4_ext_get_access(handle, inode, path + depth);
3757 if (err)
3758 goto out;
3759 /* first mark the extent as initialized */
3760 ext4_ext_mark_initialized(ex);
3761
3762 /* note: ext4_ext_correct_indexes() isn't needed here because
3763 * borders are not changed
3764 */
3765 ext4_ext_try_to_merge(handle, inode, path, ex);
3766
3767 /* Mark modified extent as dirty */
3768 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3769out:
3770 ext4_ext_show_leaf(inode, path);
3771 return err;
3772}
3773
3774static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3775 sector_t block, int count)
3776{
3777 int i;
3778 for (i = 0; i < count; i++)
3779 unmap_underlying_metadata(bdev, block + i);
3780}
3781
3782/*
3783 * Handle EOFBLOCKS_FL flag, clearing it if necessary
3784 */
3785static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3786 ext4_lblk_t lblk,
3787 struct ext4_ext_path *path,
3788 unsigned int len)
3789{
3790 int i, depth;
3791 struct ext4_extent_header *eh;
3792 struct ext4_extent *last_ex;
3793
3794 if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3795 return 0;
3796
3797 depth = ext_depth(inode);
3798 eh = path[depth].p_hdr;
3799
3800 /*
3801 * We're going to remove EOFBLOCKS_FL entirely in future so we
3802 * do not care for this case anymore. Simply remove the flag
3803 * if there are no extents.
3804 */
3805 if (unlikely(!eh->eh_entries))
3806 goto out;
3807 last_ex = EXT_LAST_EXTENT(eh);
3808 /*
3809 * We should clear the EOFBLOCKS_FL flag if we are writing the
3810 * last block in the last extent in the file. We test this by
3811 * first checking to see if the caller to
3812 * ext4_ext_get_blocks() was interested in the last block (or
3813 * a block beyond the last block) in the current extent. If
3814 * this turns out to be false, we can bail out from this
3815 * function immediately.
3816 */
3817 if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3818 ext4_ext_get_actual_len(last_ex))
3819 return 0;
3820 /*
3821 * If the caller does appear to be planning to write at or
3822 * beyond the end of the current extent, we then test to see
3823 * if the current extent is the last extent in the file, by
3824 * checking to make sure it was reached via the rightmost node
3825 * at each level of the tree.
3826 */
3827 for (i = depth-1; i >= 0; i--)
3828 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3829 return 0;
3830out:
3831 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3832 return ext4_mark_inode_dirty(handle, inode);
3833}
3834
3835/**
3836 * ext4_find_delalloc_range: find delayed allocated block in the given range.
3837 *
3838 * Return 1 if there is a delalloc block in the range, otherwise 0.
3839 */
3840int ext4_find_delalloc_range(struct inode *inode,
3841 ext4_lblk_t lblk_start,
3842 ext4_lblk_t lblk_end)
3843{
3844 struct extent_status es;
3845
3846 ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3847 if (es.es_len == 0)
3848 return 0; /* there is no delay extent in this tree */
3849 else if (es.es_lblk <= lblk_start &&
3850 lblk_start < es.es_lblk + es.es_len)
3851 return 1;
3852 else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3853 return 1;
3854 else
3855 return 0;
3856}
3857
3858int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3859{
3860 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3861 ext4_lblk_t lblk_start, lblk_end;
3862 lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
3863 lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3864
3865 return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3866}
3867
3868/**
3869 * Determines how many complete clusters (out of those specified by the 'map')
3870 * are under delalloc and were reserved quota for.
3871 * This function is called when we are writing out the blocks that were
3872 * originally written with their allocation delayed, but then the space was
3873 * allocated using fallocate() before the delayed allocation could be resolved.
3874 * The cases to look for are:
3875 * ('=' indicated delayed allocated blocks
3876 * '-' indicates non-delayed allocated blocks)
3877 * (a) partial clusters towards beginning and/or end outside of allocated range
3878 * are not delalloc'ed.
3879 * Ex:
3880 * |----c---=|====c====|====c====|===-c----|
3881 * |++++++ allocated ++++++|
3882 * ==> 4 complete clusters in above example
3883 *
3884 * (b) partial cluster (outside of allocated range) towards either end is
3885 * marked for delayed allocation. In this case, we will exclude that
3886 * cluster.
3887 * Ex:
3888 * |----====c========|========c========|
3889 * |++++++ allocated ++++++|
3890 * ==> 1 complete clusters in above example
3891 *
3892 * Ex:
3893 * |================c================|
3894 * |++++++ allocated ++++++|
3895 * ==> 0 complete clusters in above example
3896 *
3897 * The ext4_da_update_reserve_space will be called only if we
3898 * determine here that there were some "entire" clusters that span
3899 * this 'allocated' range.
3900 * In the non-bigalloc case, this function will just end up returning num_blks
3901 * without ever calling ext4_find_delalloc_range.
3902 */
3903static unsigned int
3904get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3905 unsigned int num_blks)
3906{
3907 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3908 ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3909 ext4_lblk_t lblk_from, lblk_to, c_offset;
3910 unsigned int allocated_clusters = 0;
3911
3912 alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3913 alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3914
3915 /* max possible clusters for this allocation */
3916 allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3917
3918 trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3919
3920 /* Check towards left side */
3921 c_offset = EXT4_LBLK_COFF(sbi, lblk_start);
3922 if (c_offset) {
3923 lblk_from = EXT4_LBLK_CMASK(sbi, lblk_start);
3924 lblk_to = lblk_from + c_offset - 1;
3925
3926 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3927 allocated_clusters--;
3928 }
3929
3930 /* Now check towards right. */
3931 c_offset = EXT4_LBLK_COFF(sbi, lblk_start + num_blks);
3932 if (allocated_clusters && c_offset) {
3933 lblk_from = lblk_start + num_blks;
3934 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3935
3936 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3937 allocated_clusters--;
3938 }
3939
3940 return allocated_clusters;
3941}
3942
3943static int
3944convert_initialized_extent(handle_t *handle, struct inode *inode,
3945 struct ext4_map_blocks *map,
3946 struct ext4_ext_path **ppath,
3947 unsigned int allocated)
3948{
3949 struct ext4_ext_path *path = *ppath;
3950 struct ext4_extent *ex;
3951 ext4_lblk_t ee_block;
3952 unsigned int ee_len;
3953 int depth;
3954 int err = 0;
3955
3956 /*
3957 * Make sure that the extent is no bigger than we support with
3958 * unwritten extent
3959 */
3960 if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3961 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3962
3963 depth = ext_depth(inode);
3964 ex = path[depth].p_ext;
3965 ee_block = le32_to_cpu(ex->ee_block);
3966 ee_len = ext4_ext_get_actual_len(ex);
3967
3968 ext_debug("%s: inode %lu, logical"
3969 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3970 (unsigned long long)ee_block, ee_len);
3971
3972 if (ee_block != map->m_lblk || ee_len > map->m_len) {
3973 err = ext4_split_convert_extents(handle, inode, map, ppath,
3974 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3975 if (err < 0)
3976 return err;
3977 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3978 if (IS_ERR(path))
3979 return PTR_ERR(path);
3980 depth = ext_depth(inode);
3981 ex = path[depth].p_ext;
3982 if (!ex) {
3983 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3984 (unsigned long) map->m_lblk);
3985 return -EFSCORRUPTED;
3986 }
3987 }
3988
3989 err = ext4_ext_get_access(handle, inode, path + depth);
3990 if (err)
3991 return err;
3992 /* first mark the extent as unwritten */
3993 ext4_ext_mark_unwritten(ex);
3994
3995 /* note: ext4_ext_correct_indexes() isn't needed here because
3996 * borders are not changed
3997 */
3998 ext4_ext_try_to_merge(handle, inode, path, ex);
3999
4000 /* Mark modified extent as dirty */
4001 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
4002 if (err)
4003 return err;
4004 ext4_ext_show_leaf(inode, path);
4005
4006 ext4_update_inode_fsync_trans(handle, inode, 1);
4007 err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
4008 if (err)
4009 return err;
4010 map->m_flags |= EXT4_MAP_UNWRITTEN;
4011 if (allocated > map->m_len)
4012 allocated = map->m_len;
4013 map->m_len = allocated;
4014 return allocated;
4015}
4016
4017static int
4018ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4019 struct ext4_map_blocks *map,
4020 struct ext4_ext_path **ppath, int flags,
4021 unsigned int allocated, ext4_fsblk_t newblock)
4022{
4023 struct ext4_ext_path *path = *ppath;
4024 int ret = 0;
4025 int err = 0;
4026
4027 ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4028 "block %llu, max_blocks %u, flags %x, allocated %u\n",
4029 inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4030 flags, allocated);
4031 ext4_ext_show_leaf(inode, path);
4032
4033 /*
4034 * When writing into unwritten space, we should not fail to
4035 * allocate metadata blocks for the new extent block if needed.
4036 */
4037 flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4038
4039 trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4040 allocated, newblock);
4041
4042 /* get_block() before submit the IO, split the extent */
4043 if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4044 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4045 flags | EXT4_GET_BLOCKS_CONVERT);
4046 if (ret <= 0)
4047 goto out;
4048 map->m_flags |= EXT4_MAP_UNWRITTEN;
4049 goto out;
4050 }
4051 /* IO end_io complete, convert the filled extent to written */
4052 if (flags & EXT4_GET_BLOCKS_CONVERT) {
4053 if (flags & EXT4_GET_BLOCKS_ZERO) {
4054 if (allocated > map->m_len)
4055 allocated = map->m_len;
4056 err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4057 allocated);
4058 if (err < 0)
4059 goto out2;
4060 }
4061 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4062 ppath);
4063 if (ret >= 0) {
4064 ext4_update_inode_fsync_trans(handle, inode, 1);
4065 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4066 path, map->m_len);
4067 } else
4068 err = ret;
4069 map->m_flags |= EXT4_MAP_MAPPED;
4070 map->m_pblk = newblock;
4071 if (allocated > map->m_len)
4072 allocated = map->m_len;
4073 map->m_len = allocated;
4074 goto out2;
4075 }
4076 /* buffered IO case */
4077 /*
4078 * repeat fallocate creation request
4079 * we already have an unwritten extent
4080 */
4081 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4082 map->m_flags |= EXT4_MAP_UNWRITTEN;
4083 goto map_out;
4084 }
4085
4086 /* buffered READ or buffered write_begin() lookup */
4087 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4088 /*
4089 * We have blocks reserved already. We
4090 * return allocated blocks so that delalloc
4091 * won't do block reservation for us. But
4092 * the buffer head will be unmapped so that
4093 * a read from the block returns 0s.
4094 */
4095 map->m_flags |= EXT4_MAP_UNWRITTEN;
4096 goto out1;
4097 }
4098
4099 /* buffered write, writepage time, convert*/
4100 ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4101 if (ret >= 0)
4102 ext4_update_inode_fsync_trans(handle, inode, 1);
4103out:
4104 if (ret <= 0) {
4105 err = ret;
4106 goto out2;
4107 } else
4108 allocated = ret;
4109 map->m_flags |= EXT4_MAP_NEW;
4110 /*
4111 * if we allocated more blocks than requested
4112 * we need to make sure we unmap the extra block
4113 * allocated. The actual needed block will get
4114 * unmapped later when we find the buffer_head marked
4115 * new.
4116 */
4117 if (allocated > map->m_len) {
4118 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
4119 newblock + map->m_len,
4120 allocated - map->m_len);
4121 allocated = map->m_len;
4122 }
4123 map->m_len = allocated;
4124
4125 /*
4126 * If we have done fallocate with the offset that is already
4127 * delayed allocated, we would have block reservation
4128 * and quota reservation done in the delayed write path.
4129 * But fallocate would have already updated quota and block
4130 * count for this offset. So cancel these reservation
4131 */
4132 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4133 unsigned int reserved_clusters;
4134 reserved_clusters = get_reserved_cluster_alloc(inode,
4135 map->m_lblk, map->m_len);
4136 if (reserved_clusters)
4137 ext4_da_update_reserve_space(inode,
4138 reserved_clusters,
4139 0);
4140 }
4141
4142map_out:
4143 map->m_flags |= EXT4_MAP_MAPPED;
4144 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4145 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4146 map->m_len);
4147 if (err < 0)
4148 goto out2;
4149 }
4150out1:
4151 if (allocated > map->m_len)
4152 allocated = map->m_len;
4153 ext4_ext_show_leaf(inode, path);
4154 map->m_pblk = newblock;
4155 map->m_len = allocated;
4156out2:
4157 return err ? err : allocated;
4158}
4159
4160/*
4161 * get_implied_cluster_alloc - check to see if the requested
4162 * allocation (in the map structure) overlaps with a cluster already
4163 * allocated in an extent.
4164 * @sb The filesystem superblock structure
4165 * @map The requested lblk->pblk mapping
4166 * @ex The extent structure which might contain an implied
4167 * cluster allocation
4168 *
4169 * This function is called by ext4_ext_map_blocks() after we failed to
4170 * find blocks that were already in the inode's extent tree. Hence,
4171 * we know that the beginning of the requested region cannot overlap
4172 * the extent from the inode's extent tree. There are three cases we
4173 * want to catch. The first is this case:
4174 *
4175 * |--- cluster # N--|
4176 * |--- extent ---| |---- requested region ---|
4177 * |==========|
4178 *
4179 * The second case that we need to test for is this one:
4180 *
4181 * |--------- cluster # N ----------------|
4182 * |--- requested region --| |------- extent ----|
4183 * |=======================|
4184 *
4185 * The third case is when the requested region lies between two extents
4186 * within the same cluster:
4187 * |------------- cluster # N-------------|
4188 * |----- ex -----| |---- ex_right ----|
4189 * |------ requested region ------|
4190 * |================|
4191 *
4192 * In each of the above cases, we need to set the map->m_pblk and
4193 * map->m_len so it corresponds to the return the extent labelled as
4194 * "|====|" from cluster #N, since it is already in use for data in
4195 * cluster EXT4_B2C(sbi, map->m_lblk). We will then return 1 to
4196 * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4197 * as a new "allocated" block region. Otherwise, we will return 0 and
4198 * ext4_ext_map_blocks() will then allocate one or more new clusters
4199 * by calling ext4_mb_new_blocks().
4200 */
4201static int get_implied_cluster_alloc(struct super_block *sb,
4202 struct ext4_map_blocks *map,
4203 struct ext4_extent *ex,
4204 struct ext4_ext_path *path)
4205{
4206 struct ext4_sb_info *sbi = EXT4_SB(sb);
4207 ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4208 ext4_lblk_t ex_cluster_start, ex_cluster_end;
4209 ext4_lblk_t rr_cluster_start;
4210 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4211 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4212 unsigned short ee_len = ext4_ext_get_actual_len(ex);
4213
4214 /* The extent passed in that we are trying to match */
4215 ex_cluster_start = EXT4_B2C(sbi, ee_block);
4216 ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4217
4218 /* The requested region passed into ext4_map_blocks() */
4219 rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4220
4221 if ((rr_cluster_start == ex_cluster_end) ||
4222 (rr_cluster_start == ex_cluster_start)) {
4223 if (rr_cluster_start == ex_cluster_end)
4224 ee_start += ee_len - 1;
4225 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4226 map->m_len = min(map->m_len,
4227 (unsigned) sbi->s_cluster_ratio - c_offset);
4228 /*
4229 * Check for and handle this case:
4230 *
4231 * |--------- cluster # N-------------|
4232 * |------- extent ----|
4233 * |--- requested region ---|
4234 * |===========|
4235 */
4236
4237 if (map->m_lblk < ee_block)
4238 map->m_len = min(map->m_len, ee_block - map->m_lblk);
4239
4240 /*
4241 * Check for the case where there is already another allocated
4242 * block to the right of 'ex' but before the end of the cluster.
4243 *
4244 * |------------- cluster # N-------------|
4245 * |----- ex -----| |---- ex_right ----|
4246 * |------ requested region ------|
4247 * |================|
4248 */
4249 if (map->m_lblk > ee_block) {
4250 ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4251 map->m_len = min(map->m_len, next - map->m_lblk);
4252 }
4253
4254 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4255 return 1;
4256 }
4257
4258 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4259 return 0;
4260}
4261
4262
4263/*
4264 * Block allocation/map/preallocation routine for extents based files
4265 *
4266 *
4267 * Need to be called with
4268 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4269 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4270 *
4271 * return > 0, number of of blocks already mapped/allocated
4272 * if create == 0 and these are pre-allocated blocks
4273 * buffer head is unmapped
4274 * otherwise blocks are mapped
4275 *
4276 * return = 0, if plain look up failed (blocks have not been allocated)
4277 * buffer head is unmapped
4278 *
4279 * return < 0, error case.
4280 */
4281int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4282 struct ext4_map_blocks *map, int flags)
4283{
4284 struct ext4_ext_path *path = NULL;
4285 struct ext4_extent newex, *ex, *ex2;
4286 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4287 ext4_fsblk_t newblock = 0;
4288 int free_on_err = 0, err = 0, depth, ret;
4289 unsigned int allocated = 0, offset = 0;
4290 unsigned int allocated_clusters = 0;
4291 struct ext4_allocation_request ar;
4292 ext4_lblk_t cluster_offset;
4293 bool map_from_cluster = false;
4294
4295 ext_debug("blocks %u/%u requested for inode %lu\n",
4296 map->m_lblk, map->m_len, inode->i_ino);
4297 trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4298
4299 /* find extent for this block */
4300 path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4301 if (IS_ERR(path)) {
4302 err = PTR_ERR(path);
4303 path = NULL;
4304 goto out2;
4305 }
4306
4307 depth = ext_depth(inode);
4308
4309 /*
4310 * consistent leaf must not be empty;
4311 * this situation is possible, though, _during_ tree modification;
4312 * this is why assert can't be put in ext4_find_extent()
4313 */
4314 if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4315 EXT4_ERROR_INODE(inode, "bad extent address "
4316 "lblock: %lu, depth: %d pblock %lld",
4317 (unsigned long) map->m_lblk, depth,
4318 path[depth].p_block);
4319 err = -EFSCORRUPTED;
4320 goto out2;
4321 }
4322
4323 ex = path[depth].p_ext;
4324 if (ex) {
4325 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4326 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4327 unsigned short ee_len;
4328
4329
4330 /*
4331 * unwritten extents are treated as holes, except that
4332 * we split out initialized portions during a write.
4333 */
4334 ee_len = ext4_ext_get_actual_len(ex);
4335
4336 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4337
4338 /* if found extent covers block, simply return it */
4339 if (in_range(map->m_lblk, ee_block, ee_len)) {
4340 newblock = map->m_lblk - ee_block + ee_start;
4341 /* number of remaining blocks in the extent */
4342 allocated = ee_len - (map->m_lblk - ee_block);
4343 ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4344 ee_block, ee_len, newblock);
4345
4346 /*
4347 * If the extent is initialized check whether the
4348 * caller wants to convert it to unwritten.
4349 */
4350 if ((!ext4_ext_is_unwritten(ex)) &&
4351 (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4352 allocated = convert_initialized_extent(
4353 handle, inode, map, &path,
4354 allocated);
4355 goto out2;
4356 } else if (!ext4_ext_is_unwritten(ex))
4357 goto out;
4358
4359 ret = ext4_ext_handle_unwritten_extents(
4360 handle, inode, map, &path, flags,
4361 allocated, newblock);
4362 if (ret < 0)
4363 err = ret;
4364 else
4365 allocated = ret;
4366 goto out2;
4367 }
4368 }
4369
4370 /*
4371 * requested block isn't allocated yet;
4372 * we couldn't try to create block if create flag is zero
4373 */
4374 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4375 ext4_lblk_t hole_start, hole_len;
4376
4377 hole_start = map->m_lblk;
4378 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4379 /*
4380 * put just found gap into cache to speed up
4381 * subsequent requests
4382 */
4383 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4384
4385 /* Update hole_len to reflect hole size after map->m_lblk */
4386 if (hole_start != map->m_lblk)
4387 hole_len -= map->m_lblk - hole_start;
4388 map->m_pblk = 0;
4389 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4390
4391 goto out2;
4392 }
4393
4394 /*
4395 * Okay, we need to do block allocation.
4396 */
4397 newex.ee_block = cpu_to_le32(map->m_lblk);
4398 cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4399
4400 /*
4401 * If we are doing bigalloc, check to see if the extent returned
4402 * by ext4_find_extent() implies a cluster we can use.
4403 */
4404 if (cluster_offset && ex &&
4405 get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4406 ar.len = allocated = map->m_len;
4407 newblock = map->m_pblk;
4408 map_from_cluster = true;
4409 goto got_allocated_blocks;
4410 }
4411
4412 /* find neighbour allocated blocks */
4413 ar.lleft = map->m_lblk;
4414 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4415 if (err)
4416 goto out2;
4417 ar.lright = map->m_lblk;
4418 ex2 = NULL;
4419 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4420 if (err)
4421 goto out2;
4422
4423 /* Check if the extent after searching to the right implies a
4424 * cluster we can use. */
4425 if ((sbi->s_cluster_ratio > 1) && ex2 &&
4426 get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4427 ar.len = allocated = map->m_len;
4428 newblock = map->m_pblk;
4429 map_from_cluster = true;
4430 goto got_allocated_blocks;
4431 }
4432
4433 /*
4434 * See if request is beyond maximum number of blocks we can have in
4435 * a single extent. For an initialized extent this limit is
4436 * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4437 * EXT_UNWRITTEN_MAX_LEN.
4438 */
4439 if (map->m_len > EXT_INIT_MAX_LEN &&
4440 !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4441 map->m_len = EXT_INIT_MAX_LEN;
4442 else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4443 (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4444 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4445
4446 /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4447 newex.ee_len = cpu_to_le16(map->m_len);
4448 err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4449 if (err)
4450 allocated = ext4_ext_get_actual_len(&newex);
4451 else
4452 allocated = map->m_len;
4453
4454 /* allocate new block */
4455 ar.inode = inode;
4456 ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4457 ar.logical = map->m_lblk;
4458 /*
4459 * We calculate the offset from the beginning of the cluster
4460 * for the logical block number, since when we allocate a
4461 * physical cluster, the physical block should start at the
4462 * same offset from the beginning of the cluster. This is
4463 * needed so that future calls to get_implied_cluster_alloc()
4464 * work correctly.
4465 */
4466 offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4467 ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4468 ar.goal -= offset;
4469 ar.logical -= offset;
4470 if (S_ISREG(inode->i_mode))
4471 ar.flags = EXT4_MB_HINT_DATA;
4472 else
4473 /* disable in-core preallocation for non-regular files */
4474 ar.flags = 0;
4475 if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4476 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4477 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4478 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4479 if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4480 ar.flags |= EXT4_MB_USE_RESERVED;
4481 newblock = ext4_mb_new_blocks(handle, &ar, &err);
4482 if (!newblock)
4483 goto out2;
4484 ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4485 ar.goal, newblock, allocated);
4486 free_on_err = 1;
4487 allocated_clusters = ar.len;
4488 ar.len = EXT4_C2B(sbi, ar.len) - offset;
4489 if (ar.len > allocated)
4490 ar.len = allocated;
4491
4492got_allocated_blocks:
4493 /* try to insert new extent into found leaf and return */
4494 ext4_ext_store_pblock(&newex, newblock + offset);
4495 newex.ee_len = cpu_to_le16(ar.len);
4496 /* Mark unwritten */
4497 if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4498 ext4_ext_mark_unwritten(&newex);
4499 map->m_flags |= EXT4_MAP_UNWRITTEN;
4500 }
4501
4502 err = 0;
4503 if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4504 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4505 path, ar.len);
4506 if (!err)
4507 err = ext4_ext_insert_extent(handle, inode, &path,
4508 &newex, flags);
4509
4510 if (err && free_on_err) {
4511 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4512 EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4513 /* free data blocks we just allocated */
4514 /* not a good idea to call discard here directly,
4515 * but otherwise we'd need to call it every free() */
4516 ext4_discard_preallocations(inode);
4517 ext4_free_blocks(handle, inode, NULL, newblock,
4518 EXT4_C2B(sbi, allocated_clusters), fb_flags);
4519 goto out2;
4520 }
4521
4522 /* previous routine could use block we allocated */
4523 newblock = ext4_ext_pblock(&newex);
4524 allocated = ext4_ext_get_actual_len(&newex);
4525 if (allocated > map->m_len)
4526 allocated = map->m_len;
4527 map->m_flags |= EXT4_MAP_NEW;
4528
4529 /*
4530 * Update reserved blocks/metadata blocks after successful
4531 * block allocation which had been deferred till now.
4532 */
4533 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4534 unsigned int reserved_clusters;
4535 /*
4536 * Check how many clusters we had reserved this allocated range
4537 */
4538 reserved_clusters = get_reserved_cluster_alloc(inode,
4539 map->m_lblk, allocated);
4540 if (!map_from_cluster) {
4541 BUG_ON(allocated_clusters < reserved_clusters);
4542 if (reserved_clusters < allocated_clusters) {
4543 struct ext4_inode_info *ei = EXT4_I(inode);
4544 int reservation = allocated_clusters -
4545 reserved_clusters;
4546 /*
4547 * It seems we claimed few clusters outside of
4548 * the range of this allocation. We should give
4549 * it back to the reservation pool. This can
4550 * happen in the following case:
4551 *
4552 * * Suppose s_cluster_ratio is 4 (i.e., each
4553 * cluster has 4 blocks. Thus, the clusters
4554 * are [0-3],[4-7],[8-11]...
4555 * * First comes delayed allocation write for
4556 * logical blocks 10 & 11. Since there were no
4557 * previous delayed allocated blocks in the
4558 * range [8-11], we would reserve 1 cluster
4559 * for this write.
4560 * * Next comes write for logical blocks 3 to 8.
4561 * In this case, we will reserve 2 clusters
4562 * (for [0-3] and [4-7]; and not for [8-11] as
4563 * that range has a delayed allocated blocks.
4564 * Thus total reserved clusters now becomes 3.
4565 * * Now, during the delayed allocation writeout
4566 * time, we will first write blocks [3-8] and
4567 * allocate 3 clusters for writing these
4568 * blocks. Also, we would claim all these
4569 * three clusters above.
4570 * * Now when we come here to writeout the
4571 * blocks [10-11], we would expect to claim
4572 * the reservation of 1 cluster we had made
4573 * (and we would claim it since there are no
4574 * more delayed allocated blocks in the range
4575 * [8-11]. But our reserved cluster count had
4576 * already gone to 0.
4577 *
4578 * Thus, at the step 4 above when we determine
4579 * that there are still some unwritten delayed
4580 * allocated blocks outside of our current
4581 * block range, we should increment the
4582 * reserved clusters count so that when the
4583 * remaining blocks finally gets written, we
4584 * could claim them.
4585 */
4586 dquot_reserve_block(inode,
4587 EXT4_C2B(sbi, reservation));
4588 spin_lock(&ei->i_block_reservation_lock);
4589 ei->i_reserved_data_blocks += reservation;
4590 spin_unlock(&ei->i_block_reservation_lock);
4591 }
4592 /*
4593 * We will claim quota for all newly allocated blocks.
4594 * We're updating the reserved space *after* the
4595 * correction above so we do not accidentally free
4596 * all the metadata reservation because we might
4597 * actually need it later on.
4598 */
4599 ext4_da_update_reserve_space(inode, allocated_clusters,
4600 1);
4601 }
4602 }
4603
4604 /*
4605 * Cache the extent and update transaction to commit on fdatasync only
4606 * when it is _not_ an unwritten extent.
4607 */
4608 if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4609 ext4_update_inode_fsync_trans(handle, inode, 1);
4610 else
4611 ext4_update_inode_fsync_trans(handle, inode, 0);
4612out:
4613 if (allocated > map->m_len)
4614 allocated = map->m_len;
4615 ext4_ext_show_leaf(inode, path);
4616 map->m_flags |= EXT4_MAP_MAPPED;
4617 map->m_pblk = newblock;
4618 map->m_len = allocated;
4619out2:
4620 ext4_ext_drop_refs(path);
4621 kfree(path);
4622
4623 trace_ext4_ext_map_blocks_exit(inode, flags, map,
4624 err ? err : allocated);
4625 return err ? err : allocated;
4626}
4627
4628void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4629{
4630 struct super_block *sb = inode->i_sb;
4631 ext4_lblk_t last_block;
4632 int err = 0;
4633
4634 /*
4635 * TODO: optimization is possible here.
4636 * Probably we need not scan at all,
4637 * because page truncation is enough.
4638 */
4639
4640 /* we have to know where to truncate from in crash case */
4641 EXT4_I(inode)->i_disksize = inode->i_size;
4642 ext4_mark_inode_dirty(handle, inode);
4643
4644 last_block = (inode->i_size + sb->s_blocksize - 1)
4645 >> EXT4_BLOCK_SIZE_BITS(sb);
4646retry:
4647 err = ext4_es_remove_extent(inode, last_block,
4648 EXT_MAX_BLOCKS - last_block);
4649 if (err == -ENOMEM) {
4650 cond_resched();
4651 congestion_wait(BLK_RW_ASYNC, HZ/50);
4652 goto retry;
4653 }
4654 if (err) {
4655 ext4_std_error(inode->i_sb, err);
4656 return;
4657 }
4658 err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4659 ext4_std_error(inode->i_sb, err);
4660}
4661
4662static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4663 ext4_lblk_t len, loff_t new_size,
4664 int flags, int mode)
4665{
4666 struct inode *inode = file_inode(file);
4667 handle_t *handle;
4668 int ret = 0;
4669 int ret2 = 0;
4670 int retries = 0;
4671 int depth = 0;
4672 struct ext4_map_blocks map;
4673 unsigned int credits;
4674 loff_t epos;
4675
4676 map.m_lblk = offset;
4677 map.m_len = len;
4678 /*
4679 * Don't normalize the request if it can fit in one extent so
4680 * that it doesn't get unnecessarily split into multiple
4681 * extents.
4682 */
4683 if (len <= EXT_UNWRITTEN_MAX_LEN)
4684 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4685
4686 /*
4687 * credits to insert 1 extent into extent tree
4688 */
4689 credits = ext4_chunk_trans_blocks(inode, len);
4690 /*
4691 * We can only call ext_depth() on extent based inodes
4692 */
4693 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4694 depth = ext_depth(inode);
4695 else
4696 depth = -1;
4697
4698retry:
4699 while (ret >= 0 && len) {
4700 /*
4701 * Recalculate credits when extent tree depth changes.
4702 */
4703 if (depth >= 0 && depth != ext_depth(inode)) {
4704 credits = ext4_chunk_trans_blocks(inode, len);
4705 depth = ext_depth(inode);
4706 }
4707
4708 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4709 credits);
4710 if (IS_ERR(handle)) {
4711 ret = PTR_ERR(handle);
4712 break;
4713 }
4714 ret = ext4_map_blocks(handle, inode, &map, flags);
4715 if (ret <= 0) {
4716 ext4_debug("inode #%lu: block %u: len %u: "
4717 "ext4_ext_map_blocks returned %d",
4718 inode->i_ino, map.m_lblk,
4719 map.m_len, ret);
4720 ext4_mark_inode_dirty(handle, inode);
4721 ret2 = ext4_journal_stop(handle);
4722 break;
4723 }
4724 map.m_lblk += ret;
4725 map.m_len = len = len - ret;
4726 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4727 inode->i_ctime = ext4_current_time(inode);
4728 if (new_size) {
4729 if (epos > new_size)
4730 epos = new_size;
4731 if (ext4_update_inode_size(inode, epos) & 0x1)
4732 inode->i_mtime = inode->i_ctime;
4733 } else {
4734 if (epos > inode->i_size)
4735 ext4_set_inode_flag(inode,
4736 EXT4_INODE_EOFBLOCKS);
4737 }
4738 ext4_mark_inode_dirty(handle, inode);
4739 ret2 = ext4_journal_stop(handle);
4740 if (ret2)
4741 break;
4742 }
4743 if (ret == -ENOSPC &&
4744 ext4_should_retry_alloc(inode->i_sb, &retries)) {
4745 ret = 0;
4746 goto retry;
4747 }
4748
4749 return ret > 0 ? ret2 : ret;
4750}
4751
4752static long ext4_zero_range(struct file *file, loff_t offset,
4753 loff_t len, int mode)
4754{
4755 struct inode *inode = file_inode(file);
4756 handle_t *handle = NULL;
4757 unsigned int max_blocks;
4758 loff_t new_size = 0;
4759 int ret = 0;
4760 int flags;
4761 int credits;
4762 int partial_begin, partial_end;
4763 loff_t start, end;
4764 ext4_lblk_t lblk;
4765 unsigned int blkbits = inode->i_blkbits;
4766
4767 trace_ext4_zero_range(inode, offset, len, mode);
4768
4769 if (!S_ISREG(inode->i_mode))
4770 return -EINVAL;
4771
4772 /* Call ext4_force_commit to flush all data in case of data=journal. */
4773 if (ext4_should_journal_data(inode)) {
4774 ret = ext4_force_commit(inode->i_sb);
4775 if (ret)
4776 return ret;
4777 }
4778
4779 /*
4780 * Round up offset. This is not fallocate, we neet to zero out
4781 * blocks, so convert interior block aligned part of the range to
4782 * unwritten and possibly manually zero out unaligned parts of the
4783 * range.
4784 */
4785 start = round_up(offset, 1 << blkbits);
4786 end = round_down((offset + len), 1 << blkbits);
4787
4788 if (start < offset || end > offset + len)
4789 return -EINVAL;
4790 partial_begin = offset & ((1 << blkbits) - 1);
4791 partial_end = (offset + len) & ((1 << blkbits) - 1);
4792
4793 lblk = start >> blkbits;
4794 max_blocks = (end >> blkbits);
4795 if (max_blocks < lblk)
4796 max_blocks = 0;
4797 else
4798 max_blocks -= lblk;
4799
4800 inode_lock(inode);
4801
4802 /*
4803 * Indirect files do not support unwritten extnets
4804 */
4805 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4806 ret = -EOPNOTSUPP;
4807 goto out_mutex;
4808 }
4809
4810 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4811 offset + len > i_size_read(inode)) {
4812 new_size = offset + len;
4813 ret = inode_newsize_ok(inode, new_size);
4814 if (ret)
4815 goto out_mutex;
4816 }
4817
4818 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4819 if (mode & FALLOC_FL_KEEP_SIZE)
4820 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4821
4822 /* Wait all existing dio workers, newcomers will block on i_mutex */
4823 ext4_inode_block_unlocked_dio(inode);
4824 inode_dio_wait(inode);
4825
4826 /* Preallocate the range including the unaligned edges */
4827 if (partial_begin || partial_end) {
4828 ret = ext4_alloc_file_blocks(file,
4829 round_down(offset, 1 << blkbits) >> blkbits,
4830 (round_up((offset + len), 1 << blkbits) -
4831 round_down(offset, 1 << blkbits)) >> blkbits,
4832 new_size, flags, mode);
4833 if (ret)
4834 goto out_dio;
4835
4836 }
4837
4838 /* Zero range excluding the unaligned edges */
4839 if (max_blocks > 0) {
4840 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4841 EXT4_EX_NOCACHE);
4842
4843 /*
4844 * Prevent page faults from reinstantiating pages we have
4845 * released from page cache.
4846 */
4847 down_write(&EXT4_I(inode)->i_mmap_sem);
4848 ret = ext4_update_disksize_before_punch(inode, offset, len);
4849 if (ret) {
4850 up_write(&EXT4_I(inode)->i_mmap_sem);
4851 goto out_dio;
4852 }
4853 /* Now release the pages and zero block aligned part of pages */
4854 truncate_pagecache_range(inode, start, end - 1);
4855 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4856
4857 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4858 flags, mode);
4859 up_write(&EXT4_I(inode)->i_mmap_sem);
4860 if (ret)
4861 goto out_dio;
4862 }
4863 if (!partial_begin && !partial_end)
4864 goto out_dio;
4865
4866 /*
4867 * In worst case we have to writeout two nonadjacent unwritten
4868 * blocks and update the inode
4869 */
4870 credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4871 if (ext4_should_journal_data(inode))
4872 credits += 2;
4873 handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4874 if (IS_ERR(handle)) {
4875 ret = PTR_ERR(handle);
4876 ext4_std_error(inode->i_sb, ret);
4877 goto out_dio;
4878 }
4879
4880 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4881 if (new_size) {
4882 ext4_update_inode_size(inode, new_size);
4883 } else {
4884 /*
4885 * Mark that we allocate beyond EOF so the subsequent truncate
4886 * can proceed even if the new size is the same as i_size.
4887 */
4888 if ((offset + len) > i_size_read(inode))
4889 ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4890 }
4891 ext4_mark_inode_dirty(handle, inode);
4892
4893 /* Zero out partial block at the edges of the range */
4894 ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4895
4896 if (file->f_flags & O_SYNC)
4897 ext4_handle_sync(handle);
4898
4899 ext4_journal_stop(handle);
4900out_dio:
4901 ext4_inode_resume_unlocked_dio(inode);
4902out_mutex:
4903 inode_unlock(inode);
4904 return ret;
4905}
4906
4907/*
4908 * preallocate space for a file. This implements ext4's fallocate file
4909 * operation, which gets called from sys_fallocate system call.
4910 * For block-mapped files, posix_fallocate should fall back to the method
4911 * of writing zeroes to the required new blocks (the same behavior which is
4912 * expected for file systems which do not support fallocate() system call).
4913 */
4914long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4915{
4916 struct inode *inode = file_inode(file);
4917 loff_t new_size = 0;
4918 unsigned int max_blocks;
4919 int ret = 0;
4920 int flags;
4921 ext4_lblk_t lblk;
4922 unsigned int blkbits = inode->i_blkbits;
4923
4924 /*
4925 * Encrypted inodes can't handle collapse range or insert
4926 * range since we would need to re-encrypt blocks with a
4927 * different IV or XTS tweak (which are based on the logical
4928 * block number).
4929 *
4930 * XXX It's not clear why zero range isn't working, but we'll
4931 * leave it disabled for encrypted inodes for now. This is a
4932 * bug we should fix....
4933 */
4934 if (ext4_encrypted_inode(inode) &&
4935 (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE |
4936 FALLOC_FL_ZERO_RANGE)))
4937 return -EOPNOTSUPP;
4938
4939 /* Return error if mode is not supported */
4940 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4941 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4942 FALLOC_FL_INSERT_RANGE))
4943 return -EOPNOTSUPP;
4944
4945 if (mode & FALLOC_FL_PUNCH_HOLE)
4946 return ext4_punch_hole(inode, offset, len);
4947
4948 ret = ext4_convert_inline_data(inode);
4949 if (ret)
4950 return ret;
4951
4952 if (mode & FALLOC_FL_COLLAPSE_RANGE)
4953 return ext4_collapse_range(inode, offset, len);
4954
4955 if (mode & FALLOC_FL_INSERT_RANGE)
4956 return ext4_insert_range(inode, offset, len);
4957
4958 if (mode & FALLOC_FL_ZERO_RANGE)
4959 return ext4_zero_range(file, offset, len, mode);
4960
4961 trace_ext4_fallocate_enter(inode, offset, len, mode);
4962 lblk = offset >> blkbits;
4963 /*
4964 * We can't just convert len to max_blocks because
4965 * If blocksize = 4096 offset = 3072 and len = 2048
4966 */
4967 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4968 - lblk;
4969
4970 flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4971 if (mode & FALLOC_FL_KEEP_SIZE)
4972 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4973
4974 inode_lock(inode);
4975
4976 /*
4977 * We only support preallocation for extent-based files only
4978 */
4979 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4980 ret = -EOPNOTSUPP;
4981 goto out;
4982 }
4983
4984 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4985 offset + len > i_size_read(inode)) {
4986 new_size = offset + len;
4987 ret = inode_newsize_ok(inode, new_size);
4988 if (ret)
4989 goto out;
4990 }
4991
4992 /* Wait all existing dio workers, newcomers will block on i_mutex */
4993 ext4_inode_block_unlocked_dio(inode);
4994 inode_dio_wait(inode);
4995
4996 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4997 flags, mode);
4998 ext4_inode_resume_unlocked_dio(inode);
4999 if (ret)
5000 goto out;
5001
5002 if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
5003 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
5004 EXT4_I(inode)->i_sync_tid);
5005 }
5006out:
5007 inode_unlock(inode);
5008 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
5009 return ret;
5010}
5011
5012/*
5013 * This function convert a range of blocks to written extents
5014 * The caller of this function will pass the start offset and the size.
5015 * all unwritten extents within this range will be converted to
5016 * written extents.
5017 *
5018 * This function is called from the direct IO end io call back
5019 * function, to convert the fallocated extents after IO is completed.
5020 * Returns 0 on success.
5021 */
5022int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
5023 loff_t offset, ssize_t len)
5024{
5025 unsigned int max_blocks;
5026 int ret = 0;
5027 int ret2 = 0;
5028 struct ext4_map_blocks map;
5029 unsigned int credits, blkbits = inode->i_blkbits;
5030
5031 map.m_lblk = offset >> blkbits;
5032 /*
5033 * We can't just convert len to max_blocks because
5034 * If blocksize = 4096 offset = 3072 and len = 2048
5035 */
5036 max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
5037 map.m_lblk);
5038 /*
5039 * This is somewhat ugly but the idea is clear: When transaction is
5040 * reserved, everything goes into it. Otherwise we rather start several
5041 * smaller transactions for conversion of each extent separately.
5042 */
5043 if (handle) {
5044 handle = ext4_journal_start_reserved(handle,
5045 EXT4_HT_EXT_CONVERT);
5046 if (IS_ERR(handle))
5047 return PTR_ERR(handle);
5048 credits = 0;
5049 } else {
5050 /*
5051 * credits to insert 1 extent into extent tree
5052 */
5053 credits = ext4_chunk_trans_blocks(inode, max_blocks);
5054 }
5055 while (ret >= 0 && ret < max_blocks) {
5056 map.m_lblk += ret;
5057 map.m_len = (max_blocks -= ret);
5058 if (credits) {
5059 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
5060 credits);
5061 if (IS_ERR(handle)) {
5062 ret = PTR_ERR(handle);
5063 break;
5064 }
5065 }
5066 ret = ext4_map_blocks(handle, inode, &map,
5067 EXT4_GET_BLOCKS_IO_CONVERT_EXT);
5068 if (ret <= 0)
5069 ext4_warning(inode->i_sb,
5070 "inode #%lu: block %u: len %u: "
5071 "ext4_ext_map_blocks returned %d",
5072 inode->i_ino, map.m_lblk,
5073 map.m_len, ret);
5074 ext4_mark_inode_dirty(handle, inode);
5075 if (credits)
5076 ret2 = ext4_journal_stop(handle);
5077 if (ret <= 0 || ret2)
5078 break;
5079 }
5080 if (!credits)
5081 ret2 = ext4_journal_stop(handle);
5082 return ret > 0 ? ret2 : ret;
5083}
5084
5085/*
5086 * If newes is not existing extent (newes->ec_pblk equals zero) find
5087 * delayed extent at start of newes and update newes accordingly and
5088 * return start of the next delayed extent.
5089 *
5090 * If newes is existing extent (newes->ec_pblk is not equal zero)
5091 * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5092 * extent found. Leave newes unmodified.
5093 */
5094static int ext4_find_delayed_extent(struct inode *inode,
5095 struct extent_status *newes)
5096{
5097 struct extent_status es;
5098 ext4_lblk_t block, next_del;
5099
5100 if (newes->es_pblk == 0) {
5101 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
5102 newes->es_lblk + newes->es_len - 1, &es);
5103
5104 /*
5105 * No extent in extent-tree contains block @newes->es_pblk,
5106 * then the block may stay in 1)a hole or 2)delayed-extent.
5107 */
5108 if (es.es_len == 0)
5109 /* A hole found. */
5110 return 0;
5111
5112 if (es.es_lblk > newes->es_lblk) {
5113 /* A hole found. */
5114 newes->es_len = min(es.es_lblk - newes->es_lblk,
5115 newes->es_len);
5116 return 0;
5117 }
5118
5119 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5120 }
5121
5122 block = newes->es_lblk + newes->es_len;
5123 ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
5124 if (es.es_len == 0)
5125 next_del = EXT_MAX_BLOCKS;
5126 else
5127 next_del = es.es_lblk;
5128
5129 return next_del;
5130}
5131/* fiemap flags we can handle specified here */
5132#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
5133
5134static int ext4_xattr_fiemap(struct inode *inode,
5135 struct fiemap_extent_info *fieinfo)
5136{
5137 __u64 physical = 0;
5138 __u64 length;
5139 __u32 flags = FIEMAP_EXTENT_LAST;
5140 int blockbits = inode->i_sb->s_blocksize_bits;
5141 int error = 0;
5142
5143 /* in-inode? */
5144 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5145 struct ext4_iloc iloc;
5146 int offset; /* offset of xattr in inode */
5147
5148 error = ext4_get_inode_loc(inode, &iloc);
5149 if (error)
5150 return error;
5151 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5152 offset = EXT4_GOOD_OLD_INODE_SIZE +
5153 EXT4_I(inode)->i_extra_isize;
5154 physical += offset;
5155 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5156 flags |= FIEMAP_EXTENT_DATA_INLINE;
5157 brelse(iloc.bh);
5158 } else { /* external block */
5159 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5160 length = inode->i_sb->s_blocksize;
5161 }
5162
5163 if (physical)
5164 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5165 length, flags);
5166 return (error < 0 ? error : 0);
5167}
5168
5169int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5170 __u64 start, __u64 len)
5171{
5172 ext4_lblk_t start_blk;
5173 int error = 0;
5174
5175 if (ext4_has_inline_data(inode)) {
5176 int has_inline = 1;
5177
5178 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5179 start, len);
5180
5181 if (has_inline)
5182 return error;
5183 }
5184
5185 if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5186 error = ext4_ext_precache(inode);
5187 if (error)
5188 return error;
5189 }
5190
5191 /* fallback to generic here if not in extents fmt */
5192 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5193 return generic_block_fiemap(inode, fieinfo, start, len,
5194 ext4_get_block);
5195
5196 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
5197 return -EBADR;
5198
5199 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5200 error = ext4_xattr_fiemap(inode, fieinfo);
5201 } else {
5202 ext4_lblk_t len_blks;
5203 __u64 last_blk;
5204
5205 start_blk = start >> inode->i_sb->s_blocksize_bits;
5206 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5207 if (last_blk >= EXT_MAX_BLOCKS)
5208 last_blk = EXT_MAX_BLOCKS-1;
5209 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5210
5211 /*
5212 * Walk the extent tree gathering extent information
5213 * and pushing extents back to the user.
5214 */
5215 error = ext4_fill_fiemap_extents(inode, start_blk,
5216 len_blks, fieinfo);
5217 }
5218 return error;
5219}
5220
5221/*
5222 * ext4_access_path:
5223 * Function to access the path buffer for marking it dirty.
5224 * It also checks if there are sufficient credits left in the journal handle
5225 * to update path.
5226 */
5227static int
5228ext4_access_path(handle_t *handle, struct inode *inode,
5229 struct ext4_ext_path *path)
5230{
5231 int credits, err;
5232
5233 if (!ext4_handle_valid(handle))
5234 return 0;
5235
5236 /*
5237 * Check if need to extend journal credits
5238 * 3 for leaf, sb, and inode plus 2 (bmap and group
5239 * descriptor) for each block group; assume two block
5240 * groups
5241 */
5242 if (handle->h_buffer_credits < 7) {
5243 credits = ext4_writepage_trans_blocks(inode);
5244 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
5245 /* EAGAIN is success */
5246 if (err && err != -EAGAIN)
5247 return err;
5248 }
5249
5250 err = ext4_ext_get_access(handle, inode, path);
5251 return err;
5252}
5253
5254/*
5255 * ext4_ext_shift_path_extents:
5256 * Shift the extents of a path structure lying between path[depth].p_ext
5257 * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5258 * if it is right shift or left shift operation.
5259 */
5260static int
5261ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5262 struct inode *inode, handle_t *handle,
5263 enum SHIFT_DIRECTION SHIFT)
5264{
5265 int depth, err = 0;
5266 struct ext4_extent *ex_start, *ex_last;
5267 bool update = 0;
5268 depth = path->p_depth;
5269
5270 while (depth >= 0) {
5271 if (depth == path->p_depth) {
5272 ex_start = path[depth].p_ext;
5273 if (!ex_start)
5274 return -EFSCORRUPTED;
5275
5276 ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5277
5278 err = ext4_access_path(handle, inode, path + depth);
5279 if (err)
5280 goto out;
5281
5282 if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5283 update = 1;
5284
5285 while (ex_start <= ex_last) {
5286 if (SHIFT == SHIFT_LEFT) {
5287 le32_add_cpu(&ex_start->ee_block,
5288 -shift);
5289 /* Try to merge to the left. */
5290 if ((ex_start >
5291 EXT_FIRST_EXTENT(path[depth].p_hdr))
5292 &&
5293 ext4_ext_try_to_merge_right(inode,
5294 path, ex_start - 1))
5295 ex_last--;
5296 else
5297 ex_start++;
5298 } else {
5299 le32_add_cpu(&ex_last->ee_block, shift);
5300 ext4_ext_try_to_merge_right(inode, path,
5301 ex_last);
5302 ex_last--;
5303 }
5304 }
5305 err = ext4_ext_dirty(handle, inode, path + depth);
5306 if (err)
5307 goto out;
5308
5309 if (--depth < 0 || !update)
5310 break;
5311 }
5312
5313 /* Update index too */
5314 err = ext4_access_path(handle, inode, path + depth);
5315 if (err)
5316 goto out;
5317
5318 if (SHIFT == SHIFT_LEFT)
5319 le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5320 else
5321 le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5322 err = ext4_ext_dirty(handle, inode, path + depth);
5323 if (err)
5324 goto out;
5325
5326 /* we are done if current index is not a starting index */
5327 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5328 break;
5329
5330 depth--;
5331 }
5332
5333out:
5334 return err;
5335}
5336
5337/*
5338 * ext4_ext_shift_extents:
5339 * All the extents which lies in the range from @start to the last allocated
5340 * block for the @inode are shifted either towards left or right (depending
5341 * upon @SHIFT) by @shift blocks.
5342 * On success, 0 is returned, error otherwise.
5343 */
5344static int
5345ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5346 ext4_lblk_t start, ext4_lblk_t shift,
5347 enum SHIFT_DIRECTION SHIFT)
5348{
5349 struct ext4_ext_path *path;
5350 int ret = 0, depth;
5351 struct ext4_extent *extent;
5352 ext4_lblk_t stop, *iterator, ex_start, ex_end;
5353
5354 /* Let path point to the last extent */
5355 path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0);
5356 if (IS_ERR(path))
5357 return PTR_ERR(path);
5358
5359 depth = path->p_depth;
5360 extent = path[depth].p_ext;
5361 if (!extent)
5362 goto out;
5363
5364 stop = le32_to_cpu(extent->ee_block) +
5365 ext4_ext_get_actual_len(extent);
5366
5367 /*
5368 * In case of left shift, Don't start shifting extents until we make
5369 * sure the hole is big enough to accommodate the shift.
5370 */
5371 if (SHIFT == SHIFT_LEFT) {
5372 path = ext4_find_extent(inode, start - 1, &path, 0);
5373 if (IS_ERR(path))
5374 return PTR_ERR(path);
5375 depth = path->p_depth;
5376 extent = path[depth].p_ext;
5377 if (extent) {
5378 ex_start = le32_to_cpu(extent->ee_block);
5379 ex_end = le32_to_cpu(extent->ee_block) +
5380 ext4_ext_get_actual_len(extent);
5381 } else {
5382 ex_start = 0;
5383 ex_end = 0;
5384 }
5385
5386 if ((start == ex_start && shift > ex_start) ||
5387 (shift > start - ex_end)) {
5388 ext4_ext_drop_refs(path);
5389 kfree(path);
5390 return -EINVAL;
5391 }
5392 }
5393
5394 /*
5395 * In case of left shift, iterator points to start and it is increased
5396 * till we reach stop. In case of right shift, iterator points to stop
5397 * and it is decreased till we reach start.
5398 */
5399 if (SHIFT == SHIFT_LEFT)
5400 iterator = &start;
5401 else
5402 iterator = &stop;
5403
5404 /* Its safe to start updating extents */
5405 while (start < stop) {
5406 path = ext4_find_extent(inode, *iterator, &path, 0);
5407 if (IS_ERR(path))
5408 return PTR_ERR(path);
5409 depth = path->p_depth;
5410 extent = path[depth].p_ext;
5411 if (!extent) {
5412 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5413 (unsigned long) *iterator);
5414 return -EFSCORRUPTED;
5415 }
5416 if (SHIFT == SHIFT_LEFT && *iterator >
5417 le32_to_cpu(extent->ee_block)) {
5418 /* Hole, move to the next extent */
5419 if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5420 path[depth].p_ext++;
5421 } else {
5422 *iterator = ext4_ext_next_allocated_block(path);
5423 continue;
5424 }
5425 }
5426
5427 if (SHIFT == SHIFT_LEFT) {
5428 extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5429 *iterator = le32_to_cpu(extent->ee_block) +
5430 ext4_ext_get_actual_len(extent);
5431 } else {
5432 extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5433 *iterator = le32_to_cpu(extent->ee_block) > 0 ?
5434 le32_to_cpu(extent->ee_block) - 1 : 0;
5435 /* Update path extent in case we need to stop */
5436 while (le32_to_cpu(extent->ee_block) < start)
5437 extent++;
5438 path[depth].p_ext = extent;
5439 }
5440 ret = ext4_ext_shift_path_extents(path, shift, inode,
5441 handle, SHIFT);
5442 if (ret)
5443 break;
5444 }
5445out:
5446 ext4_ext_drop_refs(path);
5447 kfree(path);
5448 return ret;
5449}
5450
5451/*
5452 * ext4_collapse_range:
5453 * This implements the fallocate's collapse range functionality for ext4
5454 * Returns: 0 and non-zero on error.
5455 */
5456int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5457{
5458 struct super_block *sb = inode->i_sb;
5459 ext4_lblk_t punch_start, punch_stop;
5460 handle_t *handle;
5461 unsigned int credits;
5462 loff_t new_size, ioffset;
5463 int ret;
5464
5465 /*
5466 * We need to test this early because xfstests assumes that a
5467 * collapse range of (0, 1) will return EOPNOTSUPP if the file
5468 * system does not support collapse range.
5469 */
5470 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5471 return -EOPNOTSUPP;
5472
5473 /* Collapse range works only on fs block size aligned offsets. */
5474 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5475 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5476 return -EINVAL;
5477
5478 if (!S_ISREG(inode->i_mode))
5479 return -EINVAL;
5480
5481 trace_ext4_collapse_range(inode, offset, len);
5482
5483 punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5484 punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5485
5486 /* Call ext4_force_commit to flush all data in case of data=journal. */
5487 if (ext4_should_journal_data(inode)) {
5488 ret = ext4_force_commit(inode->i_sb);
5489 if (ret)
5490 return ret;
5491 }
5492
5493 inode_lock(inode);
5494 /*
5495 * There is no need to overlap collapse range with EOF, in which case
5496 * it is effectively a truncate operation
5497 */
5498 if (offset + len >= i_size_read(inode)) {
5499 ret = -EINVAL;
5500 goto out_mutex;
5501 }
5502
5503 /* Currently just for extent based files */
5504 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5505 ret = -EOPNOTSUPP;
5506 goto out_mutex;
5507 }
5508
5509 /* Wait for existing dio to complete */
5510 ext4_inode_block_unlocked_dio(inode);
5511 inode_dio_wait(inode);
5512
5513 /*
5514 * Prevent page faults from reinstantiating pages we have released from
5515 * page cache.
5516 */
5517 down_write(&EXT4_I(inode)->i_mmap_sem);
5518 /*
5519 * Need to round down offset to be aligned with page size boundary
5520 * for page size > block size.
5521 */
5522 ioffset = round_down(offset, PAGE_SIZE);
5523 /*
5524 * Write tail of the last page before removed range since it will get
5525 * removed from the page cache below.
5526 */
5527 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5528 if (ret)
5529 goto out_mmap;
5530 /*
5531 * Write data that will be shifted to preserve them when discarding
5532 * page cache below. We are also protected from pages becoming dirty
5533 * by i_mmap_sem.
5534 */
5535 ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5536 LLONG_MAX);
5537 if (ret)
5538 goto out_mmap;
5539 truncate_pagecache(inode, ioffset);
5540
5541 credits = ext4_writepage_trans_blocks(inode);
5542 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5543 if (IS_ERR(handle)) {
5544 ret = PTR_ERR(handle);
5545 goto out_mmap;
5546 }
5547
5548 down_write(&EXT4_I(inode)->i_data_sem);
5549 ext4_discard_preallocations(inode);
5550
5551 ret = ext4_es_remove_extent(inode, punch_start,
5552 EXT_MAX_BLOCKS - punch_start);
5553 if (ret) {
5554 up_write(&EXT4_I(inode)->i_data_sem);
5555 goto out_stop;
5556 }
5557
5558 ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5559 if (ret) {
5560 up_write(&EXT4_I(inode)->i_data_sem);
5561 goto out_stop;
5562 }
5563 ext4_discard_preallocations(inode);
5564
5565 ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5566 punch_stop - punch_start, SHIFT_LEFT);
5567 if (ret) {
5568 up_write(&EXT4_I(inode)->i_data_sem);
5569 goto out_stop;
5570 }
5571
5572 new_size = i_size_read(inode) - len;
5573 i_size_write(inode, new_size);
5574 EXT4_I(inode)->i_disksize = new_size;
5575
5576 up_write(&EXT4_I(inode)->i_data_sem);
5577 if (IS_SYNC(inode))
5578 ext4_handle_sync(handle);
5579 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5580 ext4_mark_inode_dirty(handle, inode);
5581
5582out_stop:
5583 ext4_journal_stop(handle);
5584out_mmap:
5585 up_write(&EXT4_I(inode)->i_mmap_sem);
5586 ext4_inode_resume_unlocked_dio(inode);
5587out_mutex:
5588 inode_unlock(inode);
5589 return ret;
5590}
5591
5592/*
5593 * ext4_insert_range:
5594 * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5595 * The data blocks starting from @offset to the EOF are shifted by @len
5596 * towards right to create a hole in the @inode. Inode size is increased
5597 * by len bytes.
5598 * Returns 0 on success, error otherwise.
5599 */
5600int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5601{
5602 struct super_block *sb = inode->i_sb;
5603 handle_t *handle;
5604 struct ext4_ext_path *path;
5605 struct ext4_extent *extent;
5606 ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5607 unsigned int credits, ee_len;
5608 int ret = 0, depth, split_flag = 0;
5609 loff_t ioffset;
5610
5611 /*
5612 * We need to test this early because xfstests assumes that an
5613 * insert range of (0, 1) will return EOPNOTSUPP if the file
5614 * system does not support insert range.
5615 */
5616 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5617 return -EOPNOTSUPP;
5618
5619 /* Insert range works only on fs block size aligned offsets. */
5620 if (offset & (EXT4_CLUSTER_SIZE(sb) - 1) ||
5621 len & (EXT4_CLUSTER_SIZE(sb) - 1))
5622 return -EINVAL;
5623
5624 if (!S_ISREG(inode->i_mode))
5625 return -EOPNOTSUPP;
5626
5627 trace_ext4_insert_range(inode, offset, len);
5628
5629 offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5630 len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5631
5632 /* Call ext4_force_commit to flush all data in case of data=journal */
5633 if (ext4_should_journal_data(inode)) {
5634 ret = ext4_force_commit(inode->i_sb);
5635 if (ret)
5636 return ret;
5637 }
5638
5639 inode_lock(inode);
5640 /* Currently just for extent based files */
5641 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5642 ret = -EOPNOTSUPP;
5643 goto out_mutex;
5644 }
5645
5646 /* Check for wrap through zero */
5647 if (inode->i_size + len > inode->i_sb->s_maxbytes) {
5648 ret = -EFBIG;
5649 goto out_mutex;
5650 }
5651
5652 /* Offset should be less than i_size */
5653 if (offset >= i_size_read(inode)) {
5654 ret = -EINVAL;
5655 goto out_mutex;
5656 }
5657
5658 /* Wait for existing dio to complete */
5659 ext4_inode_block_unlocked_dio(inode);
5660 inode_dio_wait(inode);
5661
5662 /*
5663 * Prevent page faults from reinstantiating pages we have released from
5664 * page cache.
5665 */
5666 down_write(&EXT4_I(inode)->i_mmap_sem);
5667 /*
5668 * Need to round down to align start offset to page size boundary
5669 * for page size > block size.
5670 */
5671 ioffset = round_down(offset, PAGE_SIZE);
5672 /* Write out all dirty pages */
5673 ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5674 LLONG_MAX);
5675 if (ret)
5676 goto out_mmap;
5677 truncate_pagecache(inode, ioffset);
5678
5679 credits = ext4_writepage_trans_blocks(inode);
5680 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5681 if (IS_ERR(handle)) {
5682 ret = PTR_ERR(handle);
5683 goto out_mmap;
5684 }
5685
5686 /* Expand file to avoid data loss if there is error while shifting */
5687 inode->i_size += len;
5688 EXT4_I(inode)->i_disksize += len;
5689 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
5690 ret = ext4_mark_inode_dirty(handle, inode);
5691 if (ret)
5692 goto out_stop;
5693
5694 down_write(&EXT4_I(inode)->i_data_sem);
5695 ext4_discard_preallocations(inode);
5696
5697 path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5698 if (IS_ERR(path)) {
5699 up_write(&EXT4_I(inode)->i_data_sem);
5700 goto out_stop;
5701 }
5702
5703 depth = ext_depth(inode);
5704 extent = path[depth].p_ext;
5705 if (extent) {
5706 ee_start_lblk = le32_to_cpu(extent->ee_block);
5707 ee_len = ext4_ext_get_actual_len(extent);
5708
5709 /*
5710 * If offset_lblk is not the starting block of extent, split
5711 * the extent @offset_lblk
5712 */
5713 if ((offset_lblk > ee_start_lblk) &&
5714 (offset_lblk < (ee_start_lblk + ee_len))) {
5715 if (ext4_ext_is_unwritten(extent))
5716 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5717 EXT4_EXT_MARK_UNWRIT2;
5718 ret = ext4_split_extent_at(handle, inode, &path,
5719 offset_lblk, split_flag,
5720 EXT4_EX_NOCACHE |
5721 EXT4_GET_BLOCKS_PRE_IO |
5722 EXT4_GET_BLOCKS_METADATA_NOFAIL);
5723 }
5724
5725 ext4_ext_drop_refs(path);
5726 kfree(path);
5727 if (ret < 0) {
5728 up_write(&EXT4_I(inode)->i_data_sem);
5729 goto out_stop;
5730 }
5731 }
5732
5733 ret = ext4_es_remove_extent(inode, offset_lblk,
5734 EXT_MAX_BLOCKS - offset_lblk);
5735 if (ret) {
5736 up_write(&EXT4_I(inode)->i_data_sem);
5737 goto out_stop;
5738 }
5739
5740 /*
5741 * if offset_lblk lies in a hole which is at start of file, use
5742 * ee_start_lblk to shift extents
5743 */
5744 ret = ext4_ext_shift_extents(inode, handle,
5745 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5746 len_lblk, SHIFT_RIGHT);
5747
5748 up_write(&EXT4_I(inode)->i_data_sem);
5749 if (IS_SYNC(inode))
5750 ext4_handle_sync(handle);
5751
5752out_stop:
5753 ext4_journal_stop(handle);
5754out_mmap:
5755 up_write(&EXT4_I(inode)->i_mmap_sem);
5756 ext4_inode_resume_unlocked_dio(inode);
5757out_mutex:
5758 inode_unlock(inode);
5759 return ret;
5760}
5761
5762/**
5763 * ext4_swap_extents - Swap extents between two inodes
5764 *
5765 * @inode1: First inode
5766 * @inode2: Second inode
5767 * @lblk1: Start block for first inode
5768 * @lblk2: Start block for second inode
5769 * @count: Number of blocks to swap
5770 * @mark_unwritten: Mark second inode's extents as unwritten after swap
5771 * @erp: Pointer to save error value
5772 *
5773 * This helper routine does exactly what is promise "swap extents". All other
5774 * stuff such as page-cache locking consistency, bh mapping consistency or
5775 * extent's data copying must be performed by caller.
5776 * Locking:
5777 * i_mutex is held for both inodes
5778 * i_data_sem is locked for write for both inodes
5779 * Assumptions:
5780 * All pages from requested range are locked for both inodes
5781 */
5782int
5783ext4_swap_extents(handle_t *handle, struct inode *inode1,
5784 struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5785 ext4_lblk_t count, int unwritten, int *erp)
5786{
5787 struct ext4_ext_path *path1 = NULL;
5788 struct ext4_ext_path *path2 = NULL;
5789 int replaced_count = 0;
5790
5791 BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5792 BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5793 BUG_ON(!inode_is_locked(inode1));
5794 BUG_ON(!inode_is_locked(inode2));
5795
5796 *erp = ext4_es_remove_extent(inode1, lblk1, count);
5797 if (unlikely(*erp))
5798 return 0;
5799 *erp = ext4_es_remove_extent(inode2, lblk2, count);
5800 if (unlikely(*erp))
5801 return 0;
5802
5803 while (count) {
5804 struct ext4_extent *ex1, *ex2, tmp_ex;
5805 ext4_lblk_t e1_blk, e2_blk;
5806 int e1_len, e2_len, len;
5807 int split = 0;
5808
5809 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5810 if (IS_ERR(path1)) {
5811 *erp = PTR_ERR(path1);
5812 path1 = NULL;
5813 finish:
5814 count = 0;
5815 goto repeat;
5816 }
5817 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5818 if (IS_ERR(path2)) {
5819 *erp = PTR_ERR(path2);
5820 path2 = NULL;
5821 goto finish;
5822 }
5823 ex1 = path1[path1->p_depth].p_ext;
5824 ex2 = path2[path2->p_depth].p_ext;
5825 /* Do we have somthing to swap ? */
5826 if (unlikely(!ex2 || !ex1))
5827 goto finish;
5828
5829 e1_blk = le32_to_cpu(ex1->ee_block);
5830 e2_blk = le32_to_cpu(ex2->ee_block);
5831 e1_len = ext4_ext_get_actual_len(ex1);
5832 e2_len = ext4_ext_get_actual_len(ex2);
5833
5834 /* Hole handling */
5835 if (!in_range(lblk1, e1_blk, e1_len) ||
5836 !in_range(lblk2, e2_blk, e2_len)) {
5837 ext4_lblk_t next1, next2;
5838
5839 /* if hole after extent, then go to next extent */
5840 next1 = ext4_ext_next_allocated_block(path1);
5841 next2 = ext4_ext_next_allocated_block(path2);
5842 /* If hole before extent, then shift to that extent */
5843 if (e1_blk > lblk1)
5844 next1 = e1_blk;
5845 if (e2_blk > lblk2)
5846 next2 = e1_blk;
5847 /* Do we have something to swap */
5848 if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5849 goto finish;
5850 /* Move to the rightest boundary */
5851 len = next1 - lblk1;
5852 if (len < next2 - lblk2)
5853 len = next2 - lblk2;
5854 if (len > count)
5855 len = count;
5856 lblk1 += len;
5857 lblk2 += len;
5858 count -= len;
5859 goto repeat;
5860 }
5861
5862 /* Prepare left boundary */
5863 if (e1_blk < lblk1) {
5864 split = 1;
5865 *erp = ext4_force_split_extent_at(handle, inode1,
5866 &path1, lblk1, 0);
5867 if (unlikely(*erp))
5868 goto finish;
5869 }
5870 if (e2_blk < lblk2) {
5871 split = 1;
5872 *erp = ext4_force_split_extent_at(handle, inode2,
5873 &path2, lblk2, 0);
5874 if (unlikely(*erp))
5875 goto finish;
5876 }
5877 /* ext4_split_extent_at() may result in leaf extent split,
5878 * path must to be revalidated. */
5879 if (split)
5880 goto repeat;
5881
5882 /* Prepare right boundary */
5883 len = count;
5884 if (len > e1_blk + e1_len - lblk1)
5885 len = e1_blk + e1_len - lblk1;
5886 if (len > e2_blk + e2_len - lblk2)
5887 len = e2_blk + e2_len - lblk2;
5888
5889 if (len != e1_len) {
5890 split = 1;
5891 *erp = ext4_force_split_extent_at(handle, inode1,
5892 &path1, lblk1 + len, 0);
5893 if (unlikely(*erp))
5894 goto finish;
5895 }
5896 if (len != e2_len) {
5897 split = 1;
5898 *erp = ext4_force_split_extent_at(handle, inode2,
5899 &path2, lblk2 + len, 0);
5900 if (*erp)
5901 goto finish;
5902 }
5903 /* ext4_split_extent_at() may result in leaf extent split,
5904 * path must to be revalidated. */
5905 if (split)
5906 goto repeat;
5907
5908 BUG_ON(e2_len != e1_len);
5909 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5910 if (unlikely(*erp))
5911 goto finish;
5912 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5913 if (unlikely(*erp))
5914 goto finish;
5915
5916 /* Both extents are fully inside boundaries. Swap it now */
5917 tmp_ex = *ex1;
5918 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5919 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5920 ex1->ee_len = cpu_to_le16(e2_len);
5921 ex2->ee_len = cpu_to_le16(e1_len);
5922 if (unwritten)
5923 ext4_ext_mark_unwritten(ex2);
5924 if (ext4_ext_is_unwritten(&tmp_ex))
5925 ext4_ext_mark_unwritten(ex1);
5926
5927 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5928 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5929 *erp = ext4_ext_dirty(handle, inode2, path2 +
5930 path2->p_depth);
5931 if (unlikely(*erp))
5932 goto finish;
5933 *erp = ext4_ext_dirty(handle, inode1, path1 +
5934 path1->p_depth);
5935 /*
5936 * Looks scarry ah..? second inode already points to new blocks,
5937 * and it was successfully dirtied. But luckily error may happen
5938 * only due to journal error, so full transaction will be
5939 * aborted anyway.
5940 */
5941 if (unlikely(*erp))
5942 goto finish;
5943 lblk1 += len;
5944 lblk2 += len;
5945 replaced_count += len;
5946 count -= len;
5947
5948 repeat:
5949 ext4_ext_drop_refs(path1);
5950 kfree(path1);
5951 ext4_ext_drop_refs(path2);
5952 kfree(path2);
5953 path1 = path2 = NULL;
5954 }
5955 return replaced_count;
5956}