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
48 /*
49 * ext_pblock:
50 * combine low and high parts of physical block number into ext4_fsblk_t
51 */
52 ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
53 {
54 ext4_fsblk_t block;
55
56 block = le32_to_cpu(ex->ee_start_lo);
57 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
58 return block;
59 }
60
61 /*
62 * idx_pblock:
63 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
64 */
65 ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
66 {
67 ext4_fsblk_t block;
68
69 block = le32_to_cpu(ix->ei_leaf_lo);
70 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
71 return block;
72 }
73
74 /*
75 * ext4_ext_store_pblock:
76 * stores a large physical block number into an extent struct,
77 * breaking it into parts
78 */
79 void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
80 {
81 ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
82 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
83 }
84
85 /*
86 * ext4_idx_store_pblock:
87 * stores a large physical block number into an index struct,
88 * breaking it into parts
89 */
90 static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
91 {
92 ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
93 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
94 }
95
96 static int ext4_ext_truncate_extend_restart(handle_t *handle,
97 struct inode *inode,
98 int needed)
99 {
100 int err;
101
102 if (!ext4_handle_valid(handle))
103 return 0;
104 if (handle->h_buffer_credits > needed)
105 return 0;
106 err = ext4_journal_extend(handle, needed);
107 if (err <= 0)
108 return err;
109 err = ext4_truncate_restart_trans(handle, inode, needed);
110 /*
111 * We have dropped i_data_sem so someone might have cached again
112 * an extent we are going to truncate.
113 */
114 ext4_ext_invalidate_cache(inode);
115
116 return err;
117 }
118
119 /*
120 * could return:
121 * - EROFS
122 * - ENOMEM
123 */
124 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
125 struct ext4_ext_path *path)
126 {
127 if (path->p_bh) {
128 /* path points to block */
129 return ext4_journal_get_write_access(handle, path->p_bh);
130 }
131 /* path points to leaf/index in inode body */
132 /* we use in-core data, no need to protect them */
133 return 0;
134 }
135
136 /*
137 * could return:
138 * - EROFS
139 * - ENOMEM
140 * - EIO
141 */
142 static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
143 struct ext4_ext_path *path)
144 {
145 int err;
146 if (path->p_bh) {
147 /* path points to block */
148 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
149 } else {
150 /* path points to leaf/index in inode body */
151 err = ext4_mark_inode_dirty(handle, inode);
152 }
153 return err;
154 }
155
156 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
157 struct ext4_ext_path *path,
158 ext4_lblk_t block)
159 {
160 struct ext4_inode_info *ei = EXT4_I(inode);
161 ext4_fsblk_t bg_start;
162 ext4_fsblk_t last_block;
163 ext4_grpblk_t colour;
164 ext4_group_t block_group;
165 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
166 int depth;
167
168 if (path) {
169 struct ext4_extent *ex;
170 depth = path->p_depth;
171
172 /* try to predict block placement */
173 ex = path[depth].p_ext;
174 if (ex)
175 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
176
177 /* it looks like index is empty;
178 * try to find starting block from index itself */
179 if (path[depth].p_bh)
180 return path[depth].p_bh->b_blocknr;
181 }
182
183 /* OK. use inode's group */
184 block_group = ei->i_block_group;
185 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
186 /*
187 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
188 * block groups per flexgroup, reserve the first block
189 * group for directories and special files. Regular
190 * files will start at the second block group. This
191 * tends to speed up directory access and improves
192 * fsck times.
193 */
194 block_group &= ~(flex_size-1);
195 if (S_ISREG(inode->i_mode))
196 block_group++;
197 }
198 bg_start = (block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
199 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
200 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
201
202 /*
203 * If we are doing delayed allocation, we don't need take
204 * colour into account.
205 */
206 if (test_opt(inode->i_sb, DELALLOC))
207 return bg_start;
208
209 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
210 colour = (current->pid % 16) *
211 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
212 else
213 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
214 return bg_start + colour + block;
215 }
216
217 /*
218 * Allocation for a meta data block
219 */
220 static ext4_fsblk_t
221 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
222 struct ext4_ext_path *path,
223 struct ext4_extent *ex, int *err)
224 {
225 ext4_fsblk_t goal, newblock;
226
227 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
228 newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
229 return newblock;
230 }
231
232 static int ext4_ext_space_block(struct inode *inode)
233 {
234 int size;
235
236 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
237 / sizeof(struct ext4_extent);
238 #ifdef AGGRESSIVE_TEST
239 if (size > 6)
240 size = 6;
241 #endif
242 return size;
243 }
244
245 static int ext4_ext_space_block_idx(struct inode *inode)
246 {
247 int size;
248
249 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
250 / sizeof(struct ext4_extent_idx);
251 #ifdef AGGRESSIVE_TEST
252 if (size > 5)
253 size = 5;
254 #endif
255 return size;
256 }
257
258 static int ext4_ext_space_root(struct inode *inode)
259 {
260 int size;
261
262 size = sizeof(EXT4_I(inode)->i_data);
263 size -= sizeof(struct ext4_extent_header);
264 size /= sizeof(struct ext4_extent);
265 #ifdef AGGRESSIVE_TEST
266 if (size > 3)
267 size = 3;
268 #endif
269 return size;
270 }
271
272 static int ext4_ext_space_root_idx(struct inode *inode)
273 {
274 int size;
275
276 size = sizeof(EXT4_I(inode)->i_data);
277 size -= sizeof(struct ext4_extent_header);
278 size /= sizeof(struct ext4_extent_idx);
279 #ifdef AGGRESSIVE_TEST
280 if (size > 4)
281 size = 4;
282 #endif
283 return size;
284 }
285
286 /*
287 * Calculate the number of metadata blocks needed
288 * to allocate @blocks
289 * Worse case is one block per extent
290 */
291 int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks)
292 {
293 int lcap, icap, rcap, leafs, idxs, num;
294 int newextents = blocks;
295
296 rcap = ext4_ext_space_root_idx(inode);
297 lcap = ext4_ext_space_block(inode);
298 icap = ext4_ext_space_block_idx(inode);
299
300 /* number of new leaf blocks needed */
301 num = leafs = (newextents + lcap - 1) / lcap;
302
303 /*
304 * Worse case, we need separate index block(s)
305 * to link all new leaf blocks
306 */
307 idxs = (leafs + icap - 1) / icap;
308 do {
309 num += idxs;
310 idxs = (idxs + icap - 1) / icap;
311 } while (idxs > rcap);
312
313 return num;
314 }
315
316 static int
317 ext4_ext_max_entries(struct inode *inode, int depth)
318 {
319 int max;
320
321 if (depth == ext_depth(inode)) {
322 if (depth == 0)
323 max = ext4_ext_space_root(inode);
324 else
325 max = ext4_ext_space_root_idx(inode);
326 } else {
327 if (depth == 0)
328 max = ext4_ext_space_block(inode);
329 else
330 max = ext4_ext_space_block_idx(inode);
331 }
332
333 return max;
334 }
335
336 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
337 {
338 ext4_fsblk_t block = ext_pblock(ext);
339 int len = ext4_ext_get_actual_len(ext);
340
341 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
342 }
343
344 static int ext4_valid_extent_idx(struct inode *inode,
345 struct ext4_extent_idx *ext_idx)
346 {
347 ext4_fsblk_t block = idx_pblock(ext_idx);
348
349 return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
350 }
351
352 static int ext4_valid_extent_entries(struct inode *inode,
353 struct ext4_extent_header *eh,
354 int depth)
355 {
356 struct ext4_extent *ext;
357 struct ext4_extent_idx *ext_idx;
358 unsigned short entries;
359 if (eh->eh_entries == 0)
360 return 1;
361
362 entries = le16_to_cpu(eh->eh_entries);
363
364 if (depth == 0) {
365 /* leaf entries */
366 ext = EXT_FIRST_EXTENT(eh);
367 while (entries) {
368 if (!ext4_valid_extent(inode, ext))
369 return 0;
370 ext++;
371 entries--;
372 }
373 } else {
374 ext_idx = EXT_FIRST_INDEX(eh);
375 while (entries) {
376 if (!ext4_valid_extent_idx(inode, ext_idx))
377 return 0;
378 ext_idx++;
379 entries--;
380 }
381 }
382 return 1;
383 }
384
385 static int __ext4_ext_check(const char *function, struct inode *inode,
386 struct ext4_extent_header *eh,
387 int depth)
388 {
389 const char *error_msg;
390 int max = 0;
391
392 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
393 error_msg = "invalid magic";
394 goto corrupted;
395 }
396 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
397 error_msg = "unexpected eh_depth";
398 goto corrupted;
399 }
400 if (unlikely(eh->eh_max == 0)) {
401 error_msg = "invalid eh_max";
402 goto corrupted;
403 }
404 max = ext4_ext_max_entries(inode, depth);
405 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
406 error_msg = "too large eh_max";
407 goto corrupted;
408 }
409 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
410 error_msg = "invalid eh_entries";
411 goto corrupted;
412 }
413 if (!ext4_valid_extent_entries(inode, eh, depth)) {
414 error_msg = "invalid extent entries";
415 goto corrupted;
416 }
417 return 0;
418
419 corrupted:
420 ext4_error(inode->i_sb, function,
421 "bad header/extent in inode #%lu: %s - magic %x, "
422 "entries %u, max %u(%u), depth %u(%u)",
423 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
424 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
425 max, le16_to_cpu(eh->eh_depth), depth);
426
427 return -EIO;
428 }
429
430 #define ext4_ext_check(inode, eh, depth) \
431 __ext4_ext_check(__func__, inode, eh, depth)
432
433 int ext4_ext_check_inode(struct inode *inode)
434 {
435 return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
436 }
437
438 #ifdef EXT_DEBUG
439 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
440 {
441 int k, l = path->p_depth;
442
443 ext_debug("path:");
444 for (k = 0; k <= l; k++, path++) {
445 if (path->p_idx) {
446 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
447 idx_pblock(path->p_idx));
448 } else if (path->p_ext) {
449 ext_debug(" %d:%d:%llu ",
450 le32_to_cpu(path->p_ext->ee_block),
451 ext4_ext_get_actual_len(path->p_ext),
452 ext_pblock(path->p_ext));
453 } else
454 ext_debug(" []");
455 }
456 ext_debug("\n");
457 }
458
459 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
460 {
461 int depth = ext_depth(inode);
462 struct ext4_extent_header *eh;
463 struct ext4_extent *ex;
464 int i;
465
466 if (!path)
467 return;
468
469 eh = path[depth].p_hdr;
470 ex = EXT_FIRST_EXTENT(eh);
471
472 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
473 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
474 ext4_ext_get_actual_len(ex), ext_pblock(ex));
475 }
476 ext_debug("\n");
477 }
478 #else
479 #define ext4_ext_show_path(inode, path)
480 #define ext4_ext_show_leaf(inode, path)
481 #endif
482
483 void ext4_ext_drop_refs(struct ext4_ext_path *path)
484 {
485 int depth = path->p_depth;
486 int i;
487
488 for (i = 0; i <= depth; i++, path++)
489 if (path->p_bh) {
490 brelse(path->p_bh);
491 path->p_bh = NULL;
492 }
493 }
494
495 /*
496 * ext4_ext_binsearch_idx:
497 * binary search for the closest index of the given block
498 * the header must be checked before calling this
499 */
500 static void
501 ext4_ext_binsearch_idx(struct inode *inode,
502 struct ext4_ext_path *path, ext4_lblk_t block)
503 {
504 struct ext4_extent_header *eh = path->p_hdr;
505 struct ext4_extent_idx *r, *l, *m;
506
507
508 ext_debug("binsearch for %u(idx): ", block);
509
510 l = EXT_FIRST_INDEX(eh) + 1;
511 r = EXT_LAST_INDEX(eh);
512 while (l <= r) {
513 m = l + (r - l) / 2;
514 if (block < le32_to_cpu(m->ei_block))
515 r = m - 1;
516 else
517 l = m + 1;
518 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
519 m, le32_to_cpu(m->ei_block),
520 r, le32_to_cpu(r->ei_block));
521 }
522
523 path->p_idx = l - 1;
524 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
525 idx_pblock(path->p_idx));
526
527 #ifdef CHECK_BINSEARCH
528 {
529 struct ext4_extent_idx *chix, *ix;
530 int k;
531
532 chix = ix = EXT_FIRST_INDEX(eh);
533 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
534 if (k != 0 &&
535 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
536 printk(KERN_DEBUG "k=%d, ix=0x%p, "
537 "first=0x%p\n", k,
538 ix, EXT_FIRST_INDEX(eh));
539 printk(KERN_DEBUG "%u <= %u\n",
540 le32_to_cpu(ix->ei_block),
541 le32_to_cpu(ix[-1].ei_block));
542 }
543 BUG_ON(k && le32_to_cpu(ix->ei_block)
544 <= le32_to_cpu(ix[-1].ei_block));
545 if (block < le32_to_cpu(ix->ei_block))
546 break;
547 chix = ix;
548 }
549 BUG_ON(chix != path->p_idx);
550 }
551 #endif
552
553 }
554
555 /*
556 * ext4_ext_binsearch:
557 * binary search for closest extent of the given block
558 * the header must be checked before calling this
559 */
560 static void
561 ext4_ext_binsearch(struct inode *inode,
562 struct ext4_ext_path *path, ext4_lblk_t block)
563 {
564 struct ext4_extent_header *eh = path->p_hdr;
565 struct ext4_extent *r, *l, *m;
566
567 if (eh->eh_entries == 0) {
568 /*
569 * this leaf is empty:
570 * we get such a leaf in split/add case
571 */
572 return;
573 }
574
575 ext_debug("binsearch for %u: ", block);
576
577 l = EXT_FIRST_EXTENT(eh) + 1;
578 r = EXT_LAST_EXTENT(eh);
579
580 while (l <= r) {
581 m = l + (r - l) / 2;
582 if (block < le32_to_cpu(m->ee_block))
583 r = m - 1;
584 else
585 l = m + 1;
586 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
587 m, le32_to_cpu(m->ee_block),
588 r, le32_to_cpu(r->ee_block));
589 }
590
591 path->p_ext = l - 1;
592 ext_debug(" -> %d:%llu:%d ",
593 le32_to_cpu(path->p_ext->ee_block),
594 ext_pblock(path->p_ext),
595 ext4_ext_get_actual_len(path->p_ext));
596
597 #ifdef CHECK_BINSEARCH
598 {
599 struct ext4_extent *chex, *ex;
600 int k;
601
602 chex = ex = EXT_FIRST_EXTENT(eh);
603 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
604 BUG_ON(k && le32_to_cpu(ex->ee_block)
605 <= le32_to_cpu(ex[-1].ee_block));
606 if (block < le32_to_cpu(ex->ee_block))
607 break;
608 chex = ex;
609 }
610 BUG_ON(chex != path->p_ext);
611 }
612 #endif
613
614 }
615
616 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
617 {
618 struct ext4_extent_header *eh;
619
620 eh = ext_inode_hdr(inode);
621 eh->eh_depth = 0;
622 eh->eh_entries = 0;
623 eh->eh_magic = EXT4_EXT_MAGIC;
624 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
625 ext4_mark_inode_dirty(handle, inode);
626 ext4_ext_invalidate_cache(inode);
627 return 0;
628 }
629
630 struct ext4_ext_path *
631 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
632 struct ext4_ext_path *path)
633 {
634 struct ext4_extent_header *eh;
635 struct buffer_head *bh;
636 short int depth, i, ppos = 0, alloc = 0;
637
638 eh = ext_inode_hdr(inode);
639 depth = ext_depth(inode);
640
641 /* account possible depth increase */
642 if (!path) {
643 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
644 GFP_NOFS);
645 if (!path)
646 return ERR_PTR(-ENOMEM);
647 alloc = 1;
648 }
649 path[0].p_hdr = eh;
650 path[0].p_bh = NULL;
651
652 i = depth;
653 /* walk through the tree */
654 while (i) {
655 int need_to_validate = 0;
656
657 ext_debug("depth %d: num %d, max %d\n",
658 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
659
660 ext4_ext_binsearch_idx(inode, path + ppos, block);
661 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
662 path[ppos].p_depth = i;
663 path[ppos].p_ext = NULL;
664
665 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
666 if (unlikely(!bh))
667 goto err;
668 if (!bh_uptodate_or_lock(bh)) {
669 if (bh_submit_read(bh) < 0) {
670 put_bh(bh);
671 goto err;
672 }
673 /* validate the extent entries */
674 need_to_validate = 1;
675 }
676 eh = ext_block_hdr(bh);
677 ppos++;
678 BUG_ON(ppos > depth);
679 path[ppos].p_bh = bh;
680 path[ppos].p_hdr = eh;
681 i--;
682
683 if (need_to_validate && ext4_ext_check(inode, eh, i))
684 goto err;
685 }
686
687 path[ppos].p_depth = i;
688 path[ppos].p_ext = NULL;
689 path[ppos].p_idx = NULL;
690
691 /* find extent */
692 ext4_ext_binsearch(inode, path + ppos, block);
693 /* if not an empty leaf */
694 if (path[ppos].p_ext)
695 path[ppos].p_block = ext_pblock(path[ppos].p_ext);
696
697 ext4_ext_show_path(inode, path);
698
699 return path;
700
701 err:
702 ext4_ext_drop_refs(path);
703 if (alloc)
704 kfree(path);
705 return ERR_PTR(-EIO);
706 }
707
708 /*
709 * ext4_ext_insert_index:
710 * insert new index [@logical;@ptr] into the block at @curp;
711 * check where to insert: before @curp or after @curp
712 */
713 int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
714 struct ext4_ext_path *curp,
715 int logical, ext4_fsblk_t ptr)
716 {
717 struct ext4_extent_idx *ix;
718 int len, err;
719
720 err = ext4_ext_get_access(handle, inode, curp);
721 if (err)
722 return err;
723
724 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
725 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
726 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
727 /* insert after */
728 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
729 len = (len - 1) * sizeof(struct ext4_extent_idx);
730 len = len < 0 ? 0 : len;
731 ext_debug("insert new index %d after: %llu. "
732 "move %d from 0x%p to 0x%p\n",
733 logical, ptr, len,
734 (curp->p_idx + 1), (curp->p_idx + 2));
735 memmove(curp->p_idx + 2, curp->p_idx + 1, len);
736 }
737 ix = curp->p_idx + 1;
738 } else {
739 /* insert before */
740 len = len * sizeof(struct ext4_extent_idx);
741 len = len < 0 ? 0 : len;
742 ext_debug("insert new index %d before: %llu. "
743 "move %d from 0x%p to 0x%p\n",
744 logical, ptr, len,
745 curp->p_idx, (curp->p_idx + 1));
746 memmove(curp->p_idx + 1, curp->p_idx, len);
747 ix = curp->p_idx;
748 }
749
750 ix->ei_block = cpu_to_le32(logical);
751 ext4_idx_store_pblock(ix, ptr);
752 le16_add_cpu(&curp->p_hdr->eh_entries, 1);
753
754 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
755 > le16_to_cpu(curp->p_hdr->eh_max));
756 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
757
758 err = ext4_ext_dirty(handle, inode, curp);
759 ext4_std_error(inode->i_sb, err);
760
761 return err;
762 }
763
764 /*
765 * ext4_ext_split:
766 * inserts new subtree into the path, using free index entry
767 * at depth @at:
768 * - allocates all needed blocks (new leaf and all intermediate index blocks)
769 * - makes decision where to split
770 * - moves remaining extents and index entries (right to the split point)
771 * into the newly allocated blocks
772 * - initializes subtree
773 */
774 static int ext4_ext_split(handle_t *handle, struct inode *inode,
775 struct ext4_ext_path *path,
776 struct ext4_extent *newext, int at)
777 {
778 struct buffer_head *bh = NULL;
779 int depth = ext_depth(inode);
780 struct ext4_extent_header *neh;
781 struct ext4_extent_idx *fidx;
782 struct ext4_extent *ex;
783 int i = at, k, m, a;
784 ext4_fsblk_t newblock, oldblock;
785 __le32 border;
786 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
787 int err = 0;
788
789 /* make decision: where to split? */
790 /* FIXME: now decision is simplest: at current extent */
791
792 /* if current leaf will be split, then we should use
793 * border from split point */
794 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
795 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
796 border = path[depth].p_ext[1].ee_block;
797 ext_debug("leaf will be split."
798 " next leaf starts at %d\n",
799 le32_to_cpu(border));
800 } else {
801 border = newext->ee_block;
802 ext_debug("leaf will be added."
803 " next leaf starts at %d\n",
804 le32_to_cpu(border));
805 }
806
807 /*
808 * If error occurs, then we break processing
809 * and mark filesystem read-only. index won't
810 * be inserted and tree will be in consistent
811 * state. Next mount will repair buffers too.
812 */
813
814 /*
815 * Get array to track all allocated blocks.
816 * We need this to handle errors and free blocks
817 * upon them.
818 */
819 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
820 if (!ablocks)
821 return -ENOMEM;
822
823 /* allocate all needed blocks */
824 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
825 for (a = 0; a < depth - at; a++) {
826 newblock = ext4_ext_new_meta_block(handle, inode, path,
827 newext, &err);
828 if (newblock == 0)
829 goto cleanup;
830 ablocks[a] = newblock;
831 }
832
833 /* initialize new leaf */
834 newblock = ablocks[--a];
835 BUG_ON(newblock == 0);
836 bh = sb_getblk(inode->i_sb, newblock);
837 if (!bh) {
838 err = -EIO;
839 goto cleanup;
840 }
841 lock_buffer(bh);
842
843 err = ext4_journal_get_create_access(handle, bh);
844 if (err)
845 goto cleanup;
846
847 neh = ext_block_hdr(bh);
848 neh->eh_entries = 0;
849 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
850 neh->eh_magic = EXT4_EXT_MAGIC;
851 neh->eh_depth = 0;
852 ex = EXT_FIRST_EXTENT(neh);
853
854 /* move remainder of path[depth] to the new leaf */
855 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
856 /* start copy from next extent */
857 /* TODO: we could do it by single memmove */
858 m = 0;
859 path[depth].p_ext++;
860 while (path[depth].p_ext <=
861 EXT_MAX_EXTENT(path[depth].p_hdr)) {
862 ext_debug("move %d:%llu:%d in new leaf %llu\n",
863 le32_to_cpu(path[depth].p_ext->ee_block),
864 ext_pblock(path[depth].p_ext),
865 ext4_ext_get_actual_len(path[depth].p_ext),
866 newblock);
867 /*memmove(ex++, path[depth].p_ext++,
868 sizeof(struct ext4_extent));
869 neh->eh_entries++;*/
870 path[depth].p_ext++;
871 m++;
872 }
873 if (m) {
874 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
875 le16_add_cpu(&neh->eh_entries, m);
876 }
877
878 set_buffer_uptodate(bh);
879 unlock_buffer(bh);
880
881 err = ext4_handle_dirty_metadata(handle, inode, bh);
882 if (err)
883 goto cleanup;
884 brelse(bh);
885 bh = NULL;
886
887 /* correct old leaf */
888 if (m) {
889 err = ext4_ext_get_access(handle, inode, path + depth);
890 if (err)
891 goto cleanup;
892 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
893 err = ext4_ext_dirty(handle, inode, path + depth);
894 if (err)
895 goto cleanup;
896
897 }
898
899 /* create intermediate indexes */
900 k = depth - at - 1;
901 BUG_ON(k < 0);
902 if (k)
903 ext_debug("create %d intermediate indices\n", k);
904 /* insert new index into current index block */
905 /* current depth stored in i var */
906 i = depth - 1;
907 while (k--) {
908 oldblock = newblock;
909 newblock = ablocks[--a];
910 bh = sb_getblk(inode->i_sb, newblock);
911 if (!bh) {
912 err = -EIO;
913 goto cleanup;
914 }
915 lock_buffer(bh);
916
917 err = ext4_journal_get_create_access(handle, bh);
918 if (err)
919 goto cleanup;
920
921 neh = ext_block_hdr(bh);
922 neh->eh_entries = cpu_to_le16(1);
923 neh->eh_magic = EXT4_EXT_MAGIC;
924 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
925 neh->eh_depth = cpu_to_le16(depth - i);
926 fidx = EXT_FIRST_INDEX(neh);
927 fidx->ei_block = border;
928 ext4_idx_store_pblock(fidx, oldblock);
929
930 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
931 i, newblock, le32_to_cpu(border), oldblock);
932 /* copy indexes */
933 m = 0;
934 path[i].p_idx++;
935
936 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
937 EXT_MAX_INDEX(path[i].p_hdr));
938 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
939 EXT_LAST_INDEX(path[i].p_hdr));
940 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
941 ext_debug("%d: move %d:%llu in new index %llu\n", i,
942 le32_to_cpu(path[i].p_idx->ei_block),
943 idx_pblock(path[i].p_idx),
944 newblock);
945 /*memmove(++fidx, path[i].p_idx++,
946 sizeof(struct ext4_extent_idx));
947 neh->eh_entries++;
948 BUG_ON(neh->eh_entries > neh->eh_max);*/
949 path[i].p_idx++;
950 m++;
951 }
952 if (m) {
953 memmove(++fidx, path[i].p_idx - m,
954 sizeof(struct ext4_extent_idx) * m);
955 le16_add_cpu(&neh->eh_entries, m);
956 }
957 set_buffer_uptodate(bh);
958 unlock_buffer(bh);
959
960 err = ext4_handle_dirty_metadata(handle, inode, bh);
961 if (err)
962 goto cleanup;
963 brelse(bh);
964 bh = NULL;
965
966 /* correct old index */
967 if (m) {
968 err = ext4_ext_get_access(handle, inode, path + i);
969 if (err)
970 goto cleanup;
971 le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
972 err = ext4_ext_dirty(handle, inode, path + i);
973 if (err)
974 goto cleanup;
975 }
976
977 i--;
978 }
979
980 /* insert new index */
981 err = ext4_ext_insert_index(handle, inode, path + at,
982 le32_to_cpu(border), newblock);
983
984 cleanup:
985 if (bh) {
986 if (buffer_locked(bh))
987 unlock_buffer(bh);
988 brelse(bh);
989 }
990
991 if (err) {
992 /* free all allocated blocks in error case */
993 for (i = 0; i < depth; i++) {
994 if (!ablocks[i])
995 continue;
996 ext4_free_blocks(handle, inode, ablocks[i], 1, 1);
997 }
998 }
999 kfree(ablocks);
1000
1001 return err;
1002 }
1003
1004 /*
1005 * ext4_ext_grow_indepth:
1006 * implements tree growing procedure:
1007 * - allocates new block
1008 * - moves top-level data (index block or leaf) into the new block
1009 * - initializes new top-level, creating index that points to the
1010 * just created block
1011 */
1012 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1013 struct ext4_ext_path *path,
1014 struct ext4_extent *newext)
1015 {
1016 struct ext4_ext_path *curp = path;
1017 struct ext4_extent_header *neh;
1018 struct ext4_extent_idx *fidx;
1019 struct buffer_head *bh;
1020 ext4_fsblk_t newblock;
1021 int err = 0;
1022
1023 newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
1024 if (newblock == 0)
1025 return err;
1026
1027 bh = sb_getblk(inode->i_sb, newblock);
1028 if (!bh) {
1029 err = -EIO;
1030 ext4_std_error(inode->i_sb, err);
1031 return err;
1032 }
1033 lock_buffer(bh);
1034
1035 err = ext4_journal_get_create_access(handle, bh);
1036 if (err) {
1037 unlock_buffer(bh);
1038 goto out;
1039 }
1040
1041 /* move top-level index/leaf into new block */
1042 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
1043
1044 /* set size of new block */
1045 neh = ext_block_hdr(bh);
1046 /* old root could have indexes or leaves
1047 * so calculate e_max right way */
1048 if (ext_depth(inode))
1049 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
1050 else
1051 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
1052 neh->eh_magic = EXT4_EXT_MAGIC;
1053 set_buffer_uptodate(bh);
1054 unlock_buffer(bh);
1055
1056 err = ext4_handle_dirty_metadata(handle, inode, bh);
1057 if (err)
1058 goto out;
1059
1060 /* create index in new top-level index: num,max,pointer */
1061 err = ext4_ext_get_access(handle, inode, curp);
1062 if (err)
1063 goto out;
1064
1065 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
1066 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
1067 curp->p_hdr->eh_entries = cpu_to_le16(1);
1068 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
1069
1070 if (path[0].p_hdr->eh_depth)
1071 curp->p_idx->ei_block =
1072 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
1073 else
1074 curp->p_idx->ei_block =
1075 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
1076 ext4_idx_store_pblock(curp->p_idx, newblock);
1077
1078 neh = ext_inode_hdr(inode);
1079 fidx = EXT_FIRST_INDEX(neh);
1080 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1081 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1082 le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
1083
1084 neh->eh_depth = cpu_to_le16(path->p_depth + 1);
1085 err = ext4_ext_dirty(handle, inode, curp);
1086 out:
1087 brelse(bh);
1088
1089 return err;
1090 }
1091
1092 /*
1093 * ext4_ext_create_new_leaf:
1094 * finds empty index and adds new leaf.
1095 * if no free index is found, then it requests in-depth growing.
1096 */
1097 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1098 struct ext4_ext_path *path,
1099 struct ext4_extent *newext)
1100 {
1101 struct ext4_ext_path *curp;
1102 int depth, i, err = 0;
1103
1104 repeat:
1105 i = depth = ext_depth(inode);
1106
1107 /* walk up to the tree and look for free index entry */
1108 curp = path + depth;
1109 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1110 i--;
1111 curp--;
1112 }
1113
1114 /* we use already allocated block for index block,
1115 * so subsequent data blocks should be contiguous */
1116 if (EXT_HAS_FREE_INDEX(curp)) {
1117 /* if we found index with free entry, then use that
1118 * entry: create all needed subtree and add new leaf */
1119 err = ext4_ext_split(handle, inode, path, newext, i);
1120 if (err)
1121 goto out;
1122
1123 /* refill path */
1124 ext4_ext_drop_refs(path);
1125 path = ext4_ext_find_extent(inode,
1126 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1127 path);
1128 if (IS_ERR(path))
1129 err = PTR_ERR(path);
1130 } else {
1131 /* tree is full, time to grow in depth */
1132 err = ext4_ext_grow_indepth(handle, inode, path, newext);
1133 if (err)
1134 goto out;
1135
1136 /* refill path */
1137 ext4_ext_drop_refs(path);
1138 path = ext4_ext_find_extent(inode,
1139 (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1140 path);
1141 if (IS_ERR(path)) {
1142 err = PTR_ERR(path);
1143 goto out;
1144 }
1145
1146 /*
1147 * only first (depth 0 -> 1) produces free space;
1148 * in all other cases we have to split the grown tree
1149 */
1150 depth = ext_depth(inode);
1151 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1152 /* now we need to split */
1153 goto repeat;
1154 }
1155 }
1156
1157 out:
1158 return err;
1159 }
1160
1161 /*
1162 * search the closest allocated block to the left for *logical
1163 * and returns it at @logical + it's physical address at @phys
1164 * if *logical is the smallest allocated block, the function
1165 * returns 0 at @phys
1166 * return value contains 0 (success) or error code
1167 */
1168 int
1169 ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path,
1170 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1171 {
1172 struct ext4_extent_idx *ix;
1173 struct ext4_extent *ex;
1174 int depth, ee_len;
1175
1176 BUG_ON(path == NULL);
1177 depth = path->p_depth;
1178 *phys = 0;
1179
1180 if (depth == 0 && path->p_ext == NULL)
1181 return 0;
1182
1183 /* usually extent in the path covers blocks smaller
1184 * then *logical, but it can be that extent is the
1185 * first one in the file */
1186
1187 ex = path[depth].p_ext;
1188 ee_len = ext4_ext_get_actual_len(ex);
1189 if (*logical < le32_to_cpu(ex->ee_block)) {
1190 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex);
1191 while (--depth >= 0) {
1192 ix = path[depth].p_idx;
1193 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr));
1194 }
1195 return 0;
1196 }
1197
1198 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len));
1199
1200 *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1201 *phys = ext_pblock(ex) + ee_len - 1;
1202 return 0;
1203 }
1204
1205 /*
1206 * search the closest allocated block to the right for *logical
1207 * and returns it at @logical + it's physical address at @phys
1208 * if *logical is the smallest allocated block, the function
1209 * returns 0 at @phys
1210 * return value contains 0 (success) or error code
1211 */
1212 int
1213 ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path,
1214 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1215 {
1216 struct buffer_head *bh = NULL;
1217 struct ext4_extent_header *eh;
1218 struct ext4_extent_idx *ix;
1219 struct ext4_extent *ex;
1220 ext4_fsblk_t block;
1221 int depth; /* Note, NOT eh_depth; depth from top of tree */
1222 int ee_len;
1223
1224 BUG_ON(path == NULL);
1225 depth = path->p_depth;
1226 *phys = 0;
1227
1228 if (depth == 0 && path->p_ext == NULL)
1229 return 0;
1230
1231 /* usually extent in the path covers blocks smaller
1232 * then *logical, but it can be that extent is the
1233 * first one in the file */
1234
1235 ex = path[depth].p_ext;
1236 ee_len = ext4_ext_get_actual_len(ex);
1237 if (*logical < le32_to_cpu(ex->ee_block)) {
1238 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex);
1239 while (--depth >= 0) {
1240 ix = path[depth].p_idx;
1241 BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr));
1242 }
1243 *logical = le32_to_cpu(ex->ee_block);
1244 *phys = ext_pblock(ex);
1245 return 0;
1246 }
1247
1248 BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len));
1249
1250 if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1251 /* next allocated block in this leaf */
1252 ex++;
1253 *logical = le32_to_cpu(ex->ee_block);
1254 *phys = ext_pblock(ex);
1255 return 0;
1256 }
1257
1258 /* go up and search for index to the right */
1259 while (--depth >= 0) {
1260 ix = path[depth].p_idx;
1261 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1262 goto got_index;
1263 }
1264
1265 /* we've gone up to the root and found no index to the right */
1266 return 0;
1267
1268 got_index:
1269 /* we've found index to the right, let's
1270 * follow it and find the closest allocated
1271 * block to the right */
1272 ix++;
1273 block = idx_pblock(ix);
1274 while (++depth < path->p_depth) {
1275 bh = sb_bread(inode->i_sb, block);
1276 if (bh == NULL)
1277 return -EIO;
1278 eh = ext_block_hdr(bh);
1279 /* subtract from p_depth to get proper eh_depth */
1280 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1281 put_bh(bh);
1282 return -EIO;
1283 }
1284 ix = EXT_FIRST_INDEX(eh);
1285 block = idx_pblock(ix);
1286 put_bh(bh);
1287 }
1288
1289 bh = sb_bread(inode->i_sb, block);
1290 if (bh == NULL)
1291 return -EIO;
1292 eh = ext_block_hdr(bh);
1293 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1294 put_bh(bh);
1295 return -EIO;
1296 }
1297 ex = EXT_FIRST_EXTENT(eh);
1298 *logical = le32_to_cpu(ex->ee_block);
1299 *phys = ext_pblock(ex);
1300 put_bh(bh);
1301 return 0;
1302 }
1303
1304 /*
1305 * ext4_ext_next_allocated_block:
1306 * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
1307 * NOTE: it considers block number from index entry as
1308 * allocated block. Thus, index entries have to be consistent
1309 * with leaves.
1310 */
1311 static ext4_lblk_t
1312 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1313 {
1314 int depth;
1315
1316 BUG_ON(path == NULL);
1317 depth = path->p_depth;
1318
1319 if (depth == 0 && path->p_ext == NULL)
1320 return EXT_MAX_BLOCK;
1321
1322 while (depth >= 0) {
1323 if (depth == path->p_depth) {
1324 /* leaf */
1325 if (path[depth].p_ext !=
1326 EXT_LAST_EXTENT(path[depth].p_hdr))
1327 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1328 } else {
1329 /* index */
1330 if (path[depth].p_idx !=
1331 EXT_LAST_INDEX(path[depth].p_hdr))
1332 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1333 }
1334 depth--;
1335 }
1336
1337 return EXT_MAX_BLOCK;
1338 }
1339
1340 /*
1341 * ext4_ext_next_leaf_block:
1342 * returns first allocated block from next leaf or EXT_MAX_BLOCK
1343 */
1344 static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
1345 struct ext4_ext_path *path)
1346 {
1347 int depth;
1348
1349 BUG_ON(path == NULL);
1350 depth = path->p_depth;
1351
1352 /* zero-tree has no leaf blocks at all */
1353 if (depth == 0)
1354 return EXT_MAX_BLOCK;
1355
1356 /* go to index block */
1357 depth--;
1358
1359 while (depth >= 0) {
1360 if (path[depth].p_idx !=
1361 EXT_LAST_INDEX(path[depth].p_hdr))
1362 return (ext4_lblk_t)
1363 le32_to_cpu(path[depth].p_idx[1].ei_block);
1364 depth--;
1365 }
1366
1367 return EXT_MAX_BLOCK;
1368 }
1369
1370 /*
1371 * ext4_ext_correct_indexes:
1372 * if leaf gets modified and modified extent is first in the leaf,
1373 * then we have to correct all indexes above.
1374 * TODO: do we need to correct tree in all cases?
1375 */
1376 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1377 struct ext4_ext_path *path)
1378 {
1379 struct ext4_extent_header *eh;
1380 int depth = ext_depth(inode);
1381 struct ext4_extent *ex;
1382 __le32 border;
1383 int k, err = 0;
1384
1385 eh = path[depth].p_hdr;
1386 ex = path[depth].p_ext;
1387 BUG_ON(ex == NULL);
1388 BUG_ON(eh == NULL);
1389
1390 if (depth == 0) {
1391 /* there is no tree at all */
1392 return 0;
1393 }
1394
1395 if (ex != EXT_FIRST_EXTENT(eh)) {
1396 /* we correct tree if first leaf got modified only */
1397 return 0;
1398 }
1399
1400 /*
1401 * TODO: we need correction if border is smaller than current one
1402 */
1403 k = depth - 1;
1404 border = path[depth].p_ext->ee_block;
1405 err = ext4_ext_get_access(handle, inode, path + k);
1406 if (err)
1407 return err;
1408 path[k].p_idx->ei_block = border;
1409 err = ext4_ext_dirty(handle, inode, path + k);
1410 if (err)
1411 return err;
1412
1413 while (k--) {
1414 /* change all left-side indexes */
1415 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1416 break;
1417 err = ext4_ext_get_access(handle, inode, path + k);
1418 if (err)
1419 break;
1420 path[k].p_idx->ei_block = border;
1421 err = ext4_ext_dirty(handle, inode, path + k);
1422 if (err)
1423 break;
1424 }
1425
1426 return err;
1427 }
1428
1429 int
1430 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1431 struct ext4_extent *ex2)
1432 {
1433 unsigned short ext1_ee_len, ext2_ee_len, max_len;
1434
1435 /*
1436 * Make sure that either both extents are uninitialized, or
1437 * both are _not_.
1438 */
1439 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1440 return 0;
1441
1442 if (ext4_ext_is_uninitialized(ex1))
1443 max_len = EXT_UNINIT_MAX_LEN;
1444 else
1445 max_len = EXT_INIT_MAX_LEN;
1446
1447 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1448 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1449
1450 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1451 le32_to_cpu(ex2->ee_block))
1452 return 0;
1453
1454 /*
1455 * To allow future support for preallocated extents to be added
1456 * as an RO_COMPAT feature, refuse to merge to extents if
1457 * this can result in the top bit of ee_len being set.
1458 */
1459 if (ext1_ee_len + ext2_ee_len > max_len)
1460 return 0;
1461 #ifdef AGGRESSIVE_TEST
1462 if (ext1_ee_len >= 4)
1463 return 0;
1464 #endif
1465
1466 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
1467 return 1;
1468 return 0;
1469 }
1470
1471 /*
1472 * This function tries to merge the "ex" extent to the next extent in the tree.
1473 * It always tries to merge towards right. If you want to merge towards
1474 * left, pass "ex - 1" as argument instead of "ex".
1475 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1476 * 1 if they got merged.
1477 */
1478 int ext4_ext_try_to_merge(struct inode *inode,
1479 struct ext4_ext_path *path,
1480 struct ext4_extent *ex)
1481 {
1482 struct ext4_extent_header *eh;
1483 unsigned int depth, len;
1484 int merge_done = 0;
1485 int uninitialized = 0;
1486
1487 depth = ext_depth(inode);
1488 BUG_ON(path[depth].p_hdr == NULL);
1489 eh = path[depth].p_hdr;
1490
1491 while (ex < EXT_LAST_EXTENT(eh)) {
1492 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1493 break;
1494 /* merge with next extent! */
1495 if (ext4_ext_is_uninitialized(ex))
1496 uninitialized = 1;
1497 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1498 + ext4_ext_get_actual_len(ex + 1));
1499 if (uninitialized)
1500 ext4_ext_mark_uninitialized(ex);
1501
1502 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1503 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1504 * sizeof(struct ext4_extent);
1505 memmove(ex + 1, ex + 2, len);
1506 }
1507 le16_add_cpu(&eh->eh_entries, -1);
1508 merge_done = 1;
1509 WARN_ON(eh->eh_entries == 0);
1510 if (!eh->eh_entries)
1511 ext4_error(inode->i_sb, "ext4_ext_try_to_merge",
1512 "inode#%lu, eh->eh_entries = 0!", inode->i_ino);
1513 }
1514
1515 return merge_done;
1516 }
1517
1518 /*
1519 * check if a portion of the "newext" extent overlaps with an
1520 * existing extent.
1521 *
1522 * If there is an overlap discovered, it updates the length of the newext
1523 * such that there will be no overlap, and then returns 1.
1524 * If there is no overlap found, it returns 0.
1525 */
1526 unsigned int ext4_ext_check_overlap(struct inode *inode,
1527 struct ext4_extent *newext,
1528 struct ext4_ext_path *path)
1529 {
1530 ext4_lblk_t b1, b2;
1531 unsigned int depth, len1;
1532 unsigned int ret = 0;
1533
1534 b1 = le32_to_cpu(newext->ee_block);
1535 len1 = ext4_ext_get_actual_len(newext);
1536 depth = ext_depth(inode);
1537 if (!path[depth].p_ext)
1538 goto out;
1539 b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1540
1541 /*
1542 * get the next allocated block if the extent in the path
1543 * is before the requested block(s)
1544 */
1545 if (b2 < b1) {
1546 b2 = ext4_ext_next_allocated_block(path);
1547 if (b2 == EXT_MAX_BLOCK)
1548 goto out;
1549 }
1550
1551 /* check for wrap through zero on extent logical start block*/
1552 if (b1 + len1 < b1) {
1553 len1 = EXT_MAX_BLOCK - b1;
1554 newext->ee_len = cpu_to_le16(len1);
1555 ret = 1;
1556 }
1557
1558 /* check for overlap */
1559 if (b1 + len1 > b2) {
1560 newext->ee_len = cpu_to_le16(b2 - b1);
1561 ret = 1;
1562 }
1563 out:
1564 return ret;
1565 }
1566
1567 /*
1568 * ext4_ext_insert_extent:
1569 * tries to merge requsted extent into the existing extent or
1570 * inserts requested extent as new one into the tree,
1571 * creating new leaf in the no-space case.
1572 */
1573 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1574 struct ext4_ext_path *path,
1575 struct ext4_extent *newext, int flag)
1576 {
1577 struct ext4_extent_header *eh;
1578 struct ext4_extent *ex, *fex;
1579 struct ext4_extent *nearex; /* nearest extent */
1580 struct ext4_ext_path *npath = NULL;
1581 int depth, len, err;
1582 ext4_lblk_t next;
1583 unsigned uninitialized = 0;
1584
1585 BUG_ON(ext4_ext_get_actual_len(newext) == 0);
1586 depth = ext_depth(inode);
1587 ex = path[depth].p_ext;
1588 BUG_ON(path[depth].p_hdr == NULL);
1589
1590 /* try to insert block into found extent and return */
1591 if (ex && (flag != EXT4_GET_BLOCKS_DIO_CREATE_EXT)
1592 && ext4_can_extents_be_merged(inode, ex, newext)) {
1593 ext_debug("append %d block to %d:%d (from %llu)\n",
1594 ext4_ext_get_actual_len(newext),
1595 le32_to_cpu(ex->ee_block),
1596 ext4_ext_get_actual_len(ex), ext_pblock(ex));
1597 err = ext4_ext_get_access(handle, inode, path + depth);
1598 if (err)
1599 return err;
1600
1601 /*
1602 * ext4_can_extents_be_merged should have checked that either
1603 * both extents are uninitialized, or both aren't. Thus we
1604 * need to check only one of them here.
1605 */
1606 if (ext4_ext_is_uninitialized(ex))
1607 uninitialized = 1;
1608 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1609 + ext4_ext_get_actual_len(newext));
1610 if (uninitialized)
1611 ext4_ext_mark_uninitialized(ex);
1612 eh = path[depth].p_hdr;
1613 nearex = ex;
1614 goto merge;
1615 }
1616
1617 repeat:
1618 depth = ext_depth(inode);
1619 eh = path[depth].p_hdr;
1620 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1621 goto has_space;
1622
1623 /* probably next leaf has space for us? */
1624 fex = EXT_LAST_EXTENT(eh);
1625 next = ext4_ext_next_leaf_block(inode, path);
1626 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1627 && next != EXT_MAX_BLOCK) {
1628 ext_debug("next leaf block - %d\n", next);
1629 BUG_ON(npath != NULL);
1630 npath = ext4_ext_find_extent(inode, next, NULL);
1631 if (IS_ERR(npath))
1632 return PTR_ERR(npath);
1633 BUG_ON(npath->p_depth != path->p_depth);
1634 eh = npath[depth].p_hdr;
1635 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1636 ext_debug("next leaf isnt full(%d)\n",
1637 le16_to_cpu(eh->eh_entries));
1638 path = npath;
1639 goto repeat;
1640 }
1641 ext_debug("next leaf has no free space(%d,%d)\n",
1642 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1643 }
1644
1645 /*
1646 * There is no free space in the found leaf.
1647 * We're gonna add a new leaf in the tree.
1648 */
1649 err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1650 if (err)
1651 goto cleanup;
1652 depth = ext_depth(inode);
1653 eh = path[depth].p_hdr;
1654
1655 has_space:
1656 nearex = path[depth].p_ext;
1657
1658 err = ext4_ext_get_access(handle, inode, path + depth);
1659 if (err)
1660 goto cleanup;
1661
1662 if (!nearex) {
1663 /* there is no extent in this leaf, create first one */
1664 ext_debug("first extent in the leaf: %d:%llu:%d\n",
1665 le32_to_cpu(newext->ee_block),
1666 ext_pblock(newext),
1667 ext4_ext_get_actual_len(newext));
1668 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1669 } else if (le32_to_cpu(newext->ee_block)
1670 > le32_to_cpu(nearex->ee_block)) {
1671 /* BUG_ON(newext->ee_block == nearex->ee_block); */
1672 if (nearex != EXT_LAST_EXTENT(eh)) {
1673 len = EXT_MAX_EXTENT(eh) - nearex;
1674 len = (len - 1) * sizeof(struct ext4_extent);
1675 len = len < 0 ? 0 : len;
1676 ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
1677 "move %d from 0x%p to 0x%p\n",
1678 le32_to_cpu(newext->ee_block),
1679 ext_pblock(newext),
1680 ext4_ext_get_actual_len(newext),
1681 nearex, len, nearex + 1, nearex + 2);
1682 memmove(nearex + 2, nearex + 1, len);
1683 }
1684 path[depth].p_ext = nearex + 1;
1685 } else {
1686 BUG_ON(newext->ee_block == nearex->ee_block);
1687 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1688 len = len < 0 ? 0 : len;
1689 ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
1690 "move %d from 0x%p to 0x%p\n",
1691 le32_to_cpu(newext->ee_block),
1692 ext_pblock(newext),
1693 ext4_ext_get_actual_len(newext),
1694 nearex, len, nearex + 1, nearex + 2);
1695 memmove(nearex + 1, nearex, len);
1696 path[depth].p_ext = nearex;
1697 }
1698
1699 le16_add_cpu(&eh->eh_entries, 1);
1700 nearex = path[depth].p_ext;
1701 nearex->ee_block = newext->ee_block;
1702 ext4_ext_store_pblock(nearex, ext_pblock(newext));
1703 nearex->ee_len = newext->ee_len;
1704
1705 merge:
1706 /* try to merge extents to the right */
1707 if (flag != EXT4_GET_BLOCKS_DIO_CREATE_EXT)
1708 ext4_ext_try_to_merge(inode, path, nearex);
1709
1710 /* try to merge extents to the left */
1711
1712 /* time to correct all indexes above */
1713 err = ext4_ext_correct_indexes(handle, inode, path);
1714 if (err)
1715 goto cleanup;
1716
1717 err = ext4_ext_dirty(handle, inode, path + depth);
1718
1719 cleanup:
1720 if (npath) {
1721 ext4_ext_drop_refs(npath);
1722 kfree(npath);
1723 }
1724 ext4_ext_invalidate_cache(inode);
1725 return err;
1726 }
1727
1728 int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1729 ext4_lblk_t num, ext_prepare_callback func,
1730 void *cbdata)
1731 {
1732 struct ext4_ext_path *path = NULL;
1733 struct ext4_ext_cache cbex;
1734 struct ext4_extent *ex;
1735 ext4_lblk_t next, start = 0, end = 0;
1736 ext4_lblk_t last = block + num;
1737 int depth, exists, err = 0;
1738
1739 BUG_ON(func == NULL);
1740 BUG_ON(inode == NULL);
1741
1742 while (block < last && block != EXT_MAX_BLOCK) {
1743 num = last - block;
1744 /* find extent for this block */
1745 down_read(&EXT4_I(inode)->i_data_sem);
1746 path = ext4_ext_find_extent(inode, block, path);
1747 up_read(&EXT4_I(inode)->i_data_sem);
1748 if (IS_ERR(path)) {
1749 err = PTR_ERR(path);
1750 path = NULL;
1751 break;
1752 }
1753
1754 depth = ext_depth(inode);
1755 BUG_ON(path[depth].p_hdr == NULL);
1756 ex = path[depth].p_ext;
1757 next = ext4_ext_next_allocated_block(path);
1758
1759 exists = 0;
1760 if (!ex) {
1761 /* there is no extent yet, so try to allocate
1762 * all requested space */
1763 start = block;
1764 end = block + num;
1765 } else if (le32_to_cpu(ex->ee_block) > block) {
1766 /* need to allocate space before found extent */
1767 start = block;
1768 end = le32_to_cpu(ex->ee_block);
1769 if (block + num < end)
1770 end = block + num;
1771 } else if (block >= le32_to_cpu(ex->ee_block)
1772 + ext4_ext_get_actual_len(ex)) {
1773 /* need to allocate space after found extent */
1774 start = block;
1775 end = block + num;
1776 if (end >= next)
1777 end = next;
1778 } else if (block >= le32_to_cpu(ex->ee_block)) {
1779 /*
1780 * some part of requested space is covered
1781 * by found extent
1782 */
1783 start = block;
1784 end = le32_to_cpu(ex->ee_block)
1785 + ext4_ext_get_actual_len(ex);
1786 if (block + num < end)
1787 end = block + num;
1788 exists = 1;
1789 } else {
1790 BUG();
1791 }
1792 BUG_ON(end <= start);
1793
1794 if (!exists) {
1795 cbex.ec_block = start;
1796 cbex.ec_len = end - start;
1797 cbex.ec_start = 0;
1798 cbex.ec_type = EXT4_EXT_CACHE_GAP;
1799 } else {
1800 cbex.ec_block = le32_to_cpu(ex->ee_block);
1801 cbex.ec_len = ext4_ext_get_actual_len(ex);
1802 cbex.ec_start = ext_pblock(ex);
1803 cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
1804 }
1805
1806 BUG_ON(cbex.ec_len == 0);
1807 err = func(inode, path, &cbex, ex, cbdata);
1808 ext4_ext_drop_refs(path);
1809
1810 if (err < 0)
1811 break;
1812
1813 if (err == EXT_REPEAT)
1814 continue;
1815 else if (err == EXT_BREAK) {
1816 err = 0;
1817 break;
1818 }
1819
1820 if (ext_depth(inode) != depth) {
1821 /* depth was changed. we have to realloc path */
1822 kfree(path);
1823 path = NULL;
1824 }
1825
1826 block = cbex.ec_block + cbex.ec_len;
1827 }
1828
1829 if (path) {
1830 ext4_ext_drop_refs(path);
1831 kfree(path);
1832 }
1833
1834 return err;
1835 }
1836
1837 static void
1838 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1839 __u32 len, ext4_fsblk_t start, int type)
1840 {
1841 struct ext4_ext_cache *cex;
1842 BUG_ON(len == 0);
1843 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1844 cex = &EXT4_I(inode)->i_cached_extent;
1845 cex->ec_type = type;
1846 cex->ec_block = block;
1847 cex->ec_len = len;
1848 cex->ec_start = start;
1849 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1850 }
1851
1852 /*
1853 * ext4_ext_put_gap_in_cache:
1854 * calculate boundaries of the gap that the requested block fits into
1855 * and cache this gap
1856 */
1857 static void
1858 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1859 ext4_lblk_t block)
1860 {
1861 int depth = ext_depth(inode);
1862 unsigned long len;
1863 ext4_lblk_t lblock;
1864 struct ext4_extent *ex;
1865
1866 ex = path[depth].p_ext;
1867 if (ex == NULL) {
1868 /* there is no extent yet, so gap is [0;-] */
1869 lblock = 0;
1870 len = EXT_MAX_BLOCK;
1871 ext_debug("cache gap(whole file):");
1872 } else if (block < le32_to_cpu(ex->ee_block)) {
1873 lblock = block;
1874 len = le32_to_cpu(ex->ee_block) - block;
1875 ext_debug("cache gap(before): %u [%u:%u]",
1876 block,
1877 le32_to_cpu(ex->ee_block),
1878 ext4_ext_get_actual_len(ex));
1879 } else if (block >= le32_to_cpu(ex->ee_block)
1880 + ext4_ext_get_actual_len(ex)) {
1881 ext4_lblk_t next;
1882 lblock = le32_to_cpu(ex->ee_block)
1883 + ext4_ext_get_actual_len(ex);
1884
1885 next = ext4_ext_next_allocated_block(path);
1886 ext_debug("cache gap(after): [%u:%u] %u",
1887 le32_to_cpu(ex->ee_block),
1888 ext4_ext_get_actual_len(ex),
1889 block);
1890 BUG_ON(next == lblock);
1891 len = next - lblock;
1892 } else {
1893 lblock = len = 0;
1894 BUG();
1895 }
1896
1897 ext_debug(" -> %u:%lu\n", lblock, len);
1898 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1899 }
1900
1901 static int
1902 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
1903 struct ext4_extent *ex)
1904 {
1905 struct ext4_ext_cache *cex;
1906 int ret = EXT4_EXT_CACHE_NO;
1907
1908 /*
1909 * We borrow i_block_reservation_lock to protect i_cached_extent
1910 */
1911 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1912 cex = &EXT4_I(inode)->i_cached_extent;
1913
1914 /* has cache valid data? */
1915 if (cex->ec_type == EXT4_EXT_CACHE_NO)
1916 goto errout;
1917
1918 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1919 cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1920 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
1921 ex->ee_block = cpu_to_le32(cex->ec_block);
1922 ext4_ext_store_pblock(ex, cex->ec_start);
1923 ex->ee_len = cpu_to_le16(cex->ec_len);
1924 ext_debug("%u cached by %u:%u:%llu\n",
1925 block,
1926 cex->ec_block, cex->ec_len, cex->ec_start);
1927 ret = cex->ec_type;
1928 }
1929 errout:
1930 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1931 return ret;
1932 }
1933
1934 /*
1935 * ext4_ext_rm_idx:
1936 * removes index from the index block.
1937 * It's used in truncate case only, thus all requests are for
1938 * last index in the block only.
1939 */
1940 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1941 struct ext4_ext_path *path)
1942 {
1943 struct buffer_head *bh;
1944 int err;
1945 ext4_fsblk_t leaf;
1946
1947 /* free index block */
1948 path--;
1949 leaf = idx_pblock(path->p_idx);
1950 BUG_ON(path->p_hdr->eh_entries == 0);
1951 err = ext4_ext_get_access(handle, inode, path);
1952 if (err)
1953 return err;
1954 le16_add_cpu(&path->p_hdr->eh_entries, -1);
1955 err = ext4_ext_dirty(handle, inode, path);
1956 if (err)
1957 return err;
1958 ext_debug("index is empty, remove it, free block %llu\n", leaf);
1959 bh = sb_find_get_block(inode->i_sb, leaf);
1960 ext4_forget(handle, 1, inode, bh, leaf);
1961 ext4_free_blocks(handle, inode, leaf, 1, 1);
1962 return err;
1963 }
1964
1965 /*
1966 * ext4_ext_calc_credits_for_single_extent:
1967 * This routine returns max. credits that needed to insert an extent
1968 * to the extent tree.
1969 * When pass the actual path, the caller should calculate credits
1970 * under i_data_sem.
1971 */
1972 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
1973 struct ext4_ext_path *path)
1974 {
1975 if (path) {
1976 int depth = ext_depth(inode);
1977 int ret = 0;
1978
1979 /* probably there is space in leaf? */
1980 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1981 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
1982
1983 /*
1984 * There are some space in the leaf tree, no
1985 * need to account for leaf block credit
1986 *
1987 * bitmaps and block group descriptor blocks
1988 * and other metadat blocks still need to be
1989 * accounted.
1990 */
1991 /* 1 bitmap, 1 block group descriptor */
1992 ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
1993 return ret;
1994 }
1995 }
1996
1997 return ext4_chunk_trans_blocks(inode, nrblocks);
1998 }
1999
2000 /*
2001 * How many index/leaf blocks need to change/allocate to modify nrblocks?
2002 *
2003 * if nrblocks are fit in a single extent (chunk flag is 1), then
2004 * in the worse case, each tree level index/leaf need to be changed
2005 * if the tree split due to insert a new extent, then the old tree
2006 * index/leaf need to be updated too
2007 *
2008 * If the nrblocks are discontiguous, they could cause
2009 * the whole tree split more than once, but this is really rare.
2010 */
2011 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2012 {
2013 int index;
2014 int depth = ext_depth(inode);
2015
2016 if (chunk)
2017 index = depth * 2;
2018 else
2019 index = depth * 3;
2020
2021 return index;
2022 }
2023
2024 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2025 struct ext4_extent *ex,
2026 ext4_lblk_t from, ext4_lblk_t to)
2027 {
2028 struct buffer_head *bh;
2029 unsigned short ee_len = ext4_ext_get_actual_len(ex);
2030 int i, metadata = 0;
2031
2032 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2033 metadata = 1;
2034 #ifdef EXTENTS_STATS
2035 {
2036 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2037 spin_lock(&sbi->s_ext_stats_lock);
2038 sbi->s_ext_blocks += ee_len;
2039 sbi->s_ext_extents++;
2040 if (ee_len < sbi->s_ext_min)
2041 sbi->s_ext_min = ee_len;
2042 if (ee_len > sbi->s_ext_max)
2043 sbi->s_ext_max = ee_len;
2044 if (ext_depth(inode) > sbi->s_depth_max)
2045 sbi->s_depth_max = ext_depth(inode);
2046 spin_unlock(&sbi->s_ext_stats_lock);
2047 }
2048 #endif
2049 if (from >= le32_to_cpu(ex->ee_block)
2050 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2051 /* tail removal */
2052 ext4_lblk_t num;
2053 ext4_fsblk_t start;
2054
2055 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2056 start = ext_pblock(ex) + ee_len - num;
2057 ext_debug("free last %u blocks starting %llu\n", num, start);
2058 for (i = 0; i < num; i++) {
2059 bh = sb_find_get_block(inode->i_sb, start + i);
2060 ext4_forget(handle, metadata, inode, bh, start + i);
2061 }
2062 ext4_free_blocks(handle, inode, start, num, metadata);
2063 } else if (from == le32_to_cpu(ex->ee_block)
2064 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2065 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n",
2066 from, to, le32_to_cpu(ex->ee_block), ee_len);
2067 } else {
2068 printk(KERN_INFO "strange request: removal(2) "
2069 "%u-%u from %u:%u\n",
2070 from, to, le32_to_cpu(ex->ee_block), ee_len);
2071 }
2072 return 0;
2073 }
2074
2075 static int
2076 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2077 struct ext4_ext_path *path, ext4_lblk_t start)
2078 {
2079 int err = 0, correct_index = 0;
2080 int depth = ext_depth(inode), credits;
2081 struct ext4_extent_header *eh;
2082 ext4_lblk_t a, b, block;
2083 unsigned num;
2084 ext4_lblk_t ex_ee_block;
2085 unsigned short ex_ee_len;
2086 unsigned uninitialized = 0;
2087 struct ext4_extent *ex;
2088
2089 /* the header must be checked already in ext4_ext_remove_space() */
2090 ext_debug("truncate since %u in leaf\n", start);
2091 if (!path[depth].p_hdr)
2092 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2093 eh = path[depth].p_hdr;
2094 BUG_ON(eh == NULL);
2095
2096 /* find where to start removing */
2097 ex = EXT_LAST_EXTENT(eh);
2098
2099 ex_ee_block = le32_to_cpu(ex->ee_block);
2100 ex_ee_len = ext4_ext_get_actual_len(ex);
2101
2102 while (ex >= EXT_FIRST_EXTENT(eh) &&
2103 ex_ee_block + ex_ee_len > start) {
2104
2105 if (ext4_ext_is_uninitialized(ex))
2106 uninitialized = 1;
2107 else
2108 uninitialized = 0;
2109
2110 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
2111 path[depth].p_ext = ex;
2112
2113 a = ex_ee_block > start ? ex_ee_block : start;
2114 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
2115 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
2116
2117 ext_debug(" border %u:%u\n", a, b);
2118
2119 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
2120 block = 0;
2121 num = 0;
2122 BUG();
2123 } else if (a != ex_ee_block) {
2124 /* remove tail of the extent */
2125 block = ex_ee_block;
2126 num = a - block;
2127 } else if (b != ex_ee_block + ex_ee_len - 1) {
2128 /* remove head of the extent */
2129 block = a;
2130 num = b - a;
2131 /* there is no "make a hole" API yet */
2132 BUG();
2133 } else {
2134 /* remove whole extent: excellent! */
2135 block = ex_ee_block;
2136 num = 0;
2137 BUG_ON(a != ex_ee_block);
2138 BUG_ON(b != ex_ee_block + ex_ee_len - 1);
2139 }
2140
2141 /*
2142 * 3 for leaf, sb, and inode plus 2 (bmap and group
2143 * descriptor) for each block group; assume two block
2144 * groups plus ex_ee_len/blocks_per_block_group for
2145 * the worst case
2146 */
2147 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2148 if (ex == EXT_FIRST_EXTENT(eh)) {
2149 correct_index = 1;
2150 credits += (ext_depth(inode)) + 1;
2151 }
2152 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2153
2154 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2155 if (err)
2156 goto out;
2157
2158 err = ext4_ext_get_access(handle, inode, path + depth);
2159 if (err)
2160 goto out;
2161
2162 err = ext4_remove_blocks(handle, inode, ex, a, b);
2163 if (err)
2164 goto out;
2165
2166 if (num == 0) {
2167 /* this extent is removed; mark slot entirely unused */
2168 ext4_ext_store_pblock(ex, 0);
2169 le16_add_cpu(&eh->eh_entries, -1);
2170 }
2171
2172 ex->ee_block = cpu_to_le32(block);
2173 ex->ee_len = cpu_to_le16(num);
2174 /*
2175 * Do not mark uninitialized if all the blocks in the
2176 * extent have been removed.
2177 */
2178 if (uninitialized && num)
2179 ext4_ext_mark_uninitialized(ex);
2180
2181 err = ext4_ext_dirty(handle, inode, path + depth);
2182 if (err)
2183 goto out;
2184
2185 ext_debug("new extent: %u:%u:%llu\n", block, num,
2186 ext_pblock(ex));
2187 ex--;
2188 ex_ee_block = le32_to_cpu(ex->ee_block);
2189 ex_ee_len = ext4_ext_get_actual_len(ex);
2190 }
2191
2192 if (correct_index && eh->eh_entries)
2193 err = ext4_ext_correct_indexes(handle, inode, path);
2194
2195 /* if this leaf is free, then we should
2196 * remove it from index block above */
2197 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2198 err = ext4_ext_rm_idx(handle, inode, path + depth);
2199
2200 out:
2201 return err;
2202 }
2203
2204 /*
2205 * ext4_ext_more_to_rm:
2206 * returns 1 if current index has to be freed (even partial)
2207 */
2208 static int
2209 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2210 {
2211 BUG_ON(path->p_idx == NULL);
2212
2213 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2214 return 0;
2215
2216 /*
2217 * if truncate on deeper level happened, it wasn't partial,
2218 * so we have to consider current index for truncation
2219 */
2220 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2221 return 0;
2222 return 1;
2223 }
2224
2225 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
2226 {
2227 struct super_block *sb = inode->i_sb;
2228 int depth = ext_depth(inode);
2229 struct ext4_ext_path *path;
2230 handle_t *handle;
2231 int i = 0, err = 0;
2232
2233 ext_debug("truncate since %u\n", start);
2234
2235 /* probably first extent we're gonna free will be last in block */
2236 handle = ext4_journal_start(inode, depth + 1);
2237 if (IS_ERR(handle))
2238 return PTR_ERR(handle);
2239
2240 ext4_ext_invalidate_cache(inode);
2241
2242 /*
2243 * We start scanning from right side, freeing all the blocks
2244 * after i_size and walking into the tree depth-wise.
2245 */
2246 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
2247 if (path == NULL) {
2248 ext4_journal_stop(handle);
2249 return -ENOMEM;
2250 }
2251 path[0].p_hdr = ext_inode_hdr(inode);
2252 if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2253 err = -EIO;
2254 goto out;
2255 }
2256 path[0].p_depth = depth;
2257
2258 while (i >= 0 && err == 0) {
2259 if (i == depth) {
2260 /* this is leaf block */
2261 err = ext4_ext_rm_leaf(handle, inode, path, start);
2262 /* root level has p_bh == NULL, brelse() eats this */
2263 brelse(path[i].p_bh);
2264 path[i].p_bh = NULL;
2265 i--;
2266 continue;
2267 }
2268
2269 /* this is index block */
2270 if (!path[i].p_hdr) {
2271 ext_debug("initialize header\n");
2272 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2273 }
2274
2275 if (!path[i].p_idx) {
2276 /* this level hasn't been touched yet */
2277 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2278 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2279 ext_debug("init index ptr: hdr 0x%p, num %d\n",
2280 path[i].p_hdr,
2281 le16_to_cpu(path[i].p_hdr->eh_entries));
2282 } else {
2283 /* we were already here, see at next index */
2284 path[i].p_idx--;
2285 }
2286
2287 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2288 i, EXT_FIRST_INDEX(path[i].p_hdr),
2289 path[i].p_idx);
2290 if (ext4_ext_more_to_rm(path + i)) {
2291 struct buffer_head *bh;
2292 /* go to the next level */
2293 ext_debug("move to level %d (block %llu)\n",
2294 i + 1, idx_pblock(path[i].p_idx));
2295 memset(path + i + 1, 0, sizeof(*path));
2296 bh = sb_bread(sb, idx_pblock(path[i].p_idx));
2297 if (!bh) {
2298 /* should we reset i_size? */
2299 err = -EIO;
2300 break;
2301 }
2302 if (WARN_ON(i + 1 > depth)) {
2303 err = -EIO;
2304 break;
2305 }
2306 if (ext4_ext_check(inode, ext_block_hdr(bh),
2307 depth - i - 1)) {
2308 err = -EIO;
2309 break;
2310 }
2311 path[i + 1].p_bh = bh;
2312
2313 /* save actual number of indexes since this
2314 * number is changed at the next iteration */
2315 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2316 i++;
2317 } else {
2318 /* we finished processing this index, go up */
2319 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2320 /* index is empty, remove it;
2321 * handle must be already prepared by the
2322 * truncatei_leaf() */
2323 err = ext4_ext_rm_idx(handle, inode, path + i);
2324 }
2325 /* root level has p_bh == NULL, brelse() eats this */
2326 brelse(path[i].p_bh);
2327 path[i].p_bh = NULL;
2328 i--;
2329 ext_debug("return to level %d\n", i);
2330 }
2331 }
2332
2333 /* TODO: flexible tree reduction should be here */
2334 if (path->p_hdr->eh_entries == 0) {
2335 /*
2336 * truncate to zero freed all the tree,
2337 * so we need to correct eh_depth
2338 */
2339 err = ext4_ext_get_access(handle, inode, path);
2340 if (err == 0) {
2341 ext_inode_hdr(inode)->eh_depth = 0;
2342 ext_inode_hdr(inode)->eh_max =
2343 cpu_to_le16(ext4_ext_space_root(inode));
2344 err = ext4_ext_dirty(handle, inode, path);
2345 }
2346 }
2347 out:
2348 ext4_ext_drop_refs(path);
2349 kfree(path);
2350 ext4_journal_stop(handle);
2351
2352 return err;
2353 }
2354
2355 /*
2356 * called at mount time
2357 */
2358 void ext4_ext_init(struct super_block *sb)
2359 {
2360 /*
2361 * possible initialization would be here
2362 */
2363
2364 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2365 printk(KERN_INFO "EXT4-fs: file extents enabled");
2366 #ifdef AGGRESSIVE_TEST
2367 printk(", aggressive tests");
2368 #endif
2369 #ifdef CHECK_BINSEARCH
2370 printk(", check binsearch");
2371 #endif
2372 #ifdef EXTENTS_STATS
2373 printk(", stats");
2374 #endif
2375 printk("\n");
2376 #ifdef EXTENTS_STATS
2377 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2378 EXT4_SB(sb)->s_ext_min = 1 << 30;
2379 EXT4_SB(sb)->s_ext_max = 0;
2380 #endif
2381 }
2382 }
2383
2384 /*
2385 * called at umount time
2386 */
2387 void ext4_ext_release(struct super_block *sb)
2388 {
2389 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2390 return;
2391
2392 #ifdef EXTENTS_STATS
2393 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2394 struct ext4_sb_info *sbi = EXT4_SB(sb);
2395 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2396 sbi->s_ext_blocks, sbi->s_ext_extents,
2397 sbi->s_ext_blocks / sbi->s_ext_extents);
2398 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2399 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2400 }
2401 #endif
2402 }
2403
2404 static void bi_complete(struct bio *bio, int error)
2405 {
2406 complete((struct completion *)bio->bi_private);
2407 }
2408
2409 /* FIXME!! we need to try to merge to left or right after zero-out */
2410 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2411 {
2412 int ret = -EIO;
2413 struct bio *bio;
2414 int blkbits, blocksize;
2415 sector_t ee_pblock;
2416 struct completion event;
2417 unsigned int ee_len, len, done, offset;
2418
2419
2420 blkbits = inode->i_blkbits;
2421 blocksize = inode->i_sb->s_blocksize;
2422 ee_len = ext4_ext_get_actual_len(ex);
2423 ee_pblock = ext_pblock(ex);
2424
2425 /* convert ee_pblock to 512 byte sectors */
2426 ee_pblock = ee_pblock << (blkbits - 9);
2427
2428 while (ee_len > 0) {
2429
2430 if (ee_len > BIO_MAX_PAGES)
2431 len = BIO_MAX_PAGES;
2432 else
2433 len = ee_len;
2434
2435 bio = bio_alloc(GFP_NOIO, len);
2436 bio->bi_sector = ee_pblock;
2437 bio->bi_bdev = inode->i_sb->s_bdev;
2438
2439 done = 0;
2440 offset = 0;
2441 while (done < len) {
2442 ret = bio_add_page(bio, ZERO_PAGE(0),
2443 blocksize, offset);
2444 if (ret != blocksize) {
2445 /*
2446 * We can't add any more pages because of
2447 * hardware limitations. Start a new bio.
2448 */
2449 break;
2450 }
2451 done++;
2452 offset += blocksize;
2453 if (offset >= PAGE_CACHE_SIZE)
2454 offset = 0;
2455 }
2456
2457 init_completion(&event);
2458 bio->bi_private = &event;
2459 bio->bi_end_io = bi_complete;
2460 submit_bio(WRITE, bio);
2461 wait_for_completion(&event);
2462
2463 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
2464 ret = 0;
2465 else {
2466 ret = -EIO;
2467 break;
2468 }
2469 bio_put(bio);
2470 ee_len -= done;
2471 ee_pblock += done << (blkbits - 9);
2472 }
2473 return ret;
2474 }
2475
2476 #define EXT4_EXT_ZERO_LEN 7
2477 /*
2478 * This function is called by ext4_ext_get_blocks() if someone tries to write
2479 * to an uninitialized extent. It may result in splitting the uninitialized
2480 * extent into multiple extents (upto three - one initialized and two
2481 * uninitialized).
2482 * There are three possibilities:
2483 * a> There is no split required: Entire extent should be initialized
2484 * b> Splits in two extents: Write is happening at either end of the extent
2485 * c> Splits in three extents: Somone is writing in middle of the extent
2486 */
2487 static int ext4_ext_convert_to_initialized(handle_t *handle,
2488 struct inode *inode,
2489 struct ext4_ext_path *path,
2490 ext4_lblk_t iblock,
2491 unsigned int max_blocks)
2492 {
2493 struct ext4_extent *ex, newex, orig_ex;
2494 struct ext4_extent *ex1 = NULL;
2495 struct ext4_extent *ex2 = NULL;
2496 struct ext4_extent *ex3 = NULL;
2497 struct ext4_extent_header *eh;
2498 ext4_lblk_t ee_block;
2499 unsigned int allocated, ee_len, depth;
2500 ext4_fsblk_t newblock;
2501 int err = 0;
2502 int ret = 0;
2503
2504 depth = ext_depth(inode);
2505 eh = path[depth].p_hdr;
2506 ex = path[depth].p_ext;
2507 ee_block = le32_to_cpu(ex->ee_block);
2508 ee_len = ext4_ext_get_actual_len(ex);
2509 allocated = ee_len - (iblock - ee_block);
2510 newblock = iblock - ee_block + ext_pblock(ex);
2511 ex2 = ex;
2512 orig_ex.ee_block = ex->ee_block;
2513 orig_ex.ee_len = cpu_to_le16(ee_len);
2514 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex));
2515
2516 err = ext4_ext_get_access(handle, inode, path + depth);
2517 if (err)
2518 goto out;
2519 /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
2520 if (ee_len <= 2*EXT4_EXT_ZERO_LEN) {
2521 err = ext4_ext_zeroout(inode, &orig_ex);
2522 if (err)
2523 goto fix_extent_len;
2524 /* update the extent length and mark as initialized */
2525 ex->ee_block = orig_ex.ee_block;
2526 ex->ee_len = orig_ex.ee_len;
2527 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2528 ext4_ext_dirty(handle, inode, path + depth);
2529 /* zeroed the full extent */
2530 return allocated;
2531 }
2532
2533 /* ex1: ee_block to iblock - 1 : uninitialized */
2534 if (iblock > ee_block) {
2535 ex1 = ex;
2536 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2537 ext4_ext_mark_uninitialized(ex1);
2538 ex2 = &newex;
2539 }
2540 /*
2541 * for sanity, update the length of the ex2 extent before
2542 * we insert ex3, if ex1 is NULL. This is to avoid temporary
2543 * overlap of blocks.
2544 */
2545 if (!ex1 && allocated > max_blocks)
2546 ex2->ee_len = cpu_to_le16(max_blocks);
2547 /* ex3: to ee_block + ee_len : uninitialised */
2548 if (allocated > max_blocks) {
2549 unsigned int newdepth;
2550 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
2551 if (allocated <= EXT4_EXT_ZERO_LEN) {
2552 /*
2553 * iblock == ee_block is handled by the zerouout
2554 * at the beginning.
2555 * Mark first half uninitialized.
2556 * Mark second half initialized and zero out the
2557 * initialized extent
2558 */
2559 ex->ee_block = orig_ex.ee_block;
2560 ex->ee_len = cpu_to_le16(ee_len - allocated);
2561 ext4_ext_mark_uninitialized(ex);
2562 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2563 ext4_ext_dirty(handle, inode, path + depth);
2564
2565 ex3 = &newex;
2566 ex3->ee_block = cpu_to_le32(iblock);
2567 ext4_ext_store_pblock(ex3, newblock);
2568 ex3->ee_len = cpu_to_le16(allocated);
2569 err = ext4_ext_insert_extent(handle, inode, path,
2570 ex3, 0);
2571 if (err == -ENOSPC) {
2572 err = ext4_ext_zeroout(inode, &orig_ex);
2573 if (err)
2574 goto fix_extent_len;
2575 ex->ee_block = orig_ex.ee_block;
2576 ex->ee_len = orig_ex.ee_len;
2577 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2578 ext4_ext_dirty(handle, inode, path + depth);
2579 /* blocks available from iblock */
2580 return allocated;
2581
2582 } else if (err)
2583 goto fix_extent_len;
2584
2585 /*
2586 * We need to zero out the second half because
2587 * an fallocate request can update file size and
2588 * converting the second half to initialized extent
2589 * implies that we can leak some junk data to user
2590 * space.
2591 */
2592 err = ext4_ext_zeroout(inode, ex3);
2593 if (err) {
2594 /*
2595 * We should actually mark the
2596 * second half as uninit and return error
2597 * Insert would have changed the extent
2598 */
2599 depth = ext_depth(inode);
2600 ext4_ext_drop_refs(path);
2601 path = ext4_ext_find_extent(inode,
2602 iblock, path);
2603 if (IS_ERR(path)) {
2604 err = PTR_ERR(path);
2605 return err;
2606 }
2607 /* get the second half extent details */
2608 ex = path[depth].p_ext;
2609 err = ext4_ext_get_access(handle, inode,
2610 path + depth);
2611 if (err)
2612 return err;
2613 ext4_ext_mark_uninitialized(ex);
2614 ext4_ext_dirty(handle, inode, path + depth);
2615 return err;
2616 }
2617
2618 /* zeroed the second half */
2619 return allocated;
2620 }
2621 ex3 = &newex;
2622 ex3->ee_block = cpu_to_le32(iblock + max_blocks);
2623 ext4_ext_store_pblock(ex3, newblock + max_blocks);
2624 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
2625 ext4_ext_mark_uninitialized(ex3);
2626 err = ext4_ext_insert_extent(handle, inode, path, ex3, 0);
2627 if (err == -ENOSPC) {
2628 err = ext4_ext_zeroout(inode, &orig_ex);
2629 if (err)
2630 goto fix_extent_len;
2631 /* update the extent length and mark as initialized */
2632 ex->ee_block = orig_ex.ee_block;
2633 ex->ee_len = orig_ex.ee_len;
2634 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2635 ext4_ext_dirty(handle, inode, path + depth);
2636 /* zeroed the full extent */
2637 /* blocks available from iblock */
2638 return allocated;
2639
2640 } else if (err)
2641 goto fix_extent_len;
2642 /*
2643 * The depth, and hence eh & ex might change
2644 * as part of the insert above.
2645 */
2646 newdepth = ext_depth(inode);
2647 /*
2648 * update the extent length after successful insert of the
2649 * split extent
2650 */
2651 orig_ex.ee_len = cpu_to_le16(ee_len -
2652 ext4_ext_get_actual_len(ex3));
2653 depth = newdepth;
2654 ext4_ext_drop_refs(path);
2655 path = ext4_ext_find_extent(inode, iblock, path);
2656 if (IS_ERR(path)) {
2657 err = PTR_ERR(path);
2658 goto out;
2659 }
2660 eh = path[depth].p_hdr;
2661 ex = path[depth].p_ext;
2662 if (ex2 != &newex)
2663 ex2 = ex;
2664
2665 err = ext4_ext_get_access(handle, inode, path + depth);
2666 if (err)
2667 goto out;
2668
2669 allocated = max_blocks;
2670
2671 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying
2672 * to insert a extent in the middle zerout directly
2673 * otherwise give the extent a chance to merge to left
2674 */
2675 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN &&
2676 iblock != ee_block) {
2677 err = ext4_ext_zeroout(inode, &orig_ex);
2678 if (err)
2679 goto fix_extent_len;
2680 /* update the extent length and mark as initialized */
2681 ex->ee_block = orig_ex.ee_block;
2682 ex->ee_len = orig_ex.ee_len;
2683 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2684 ext4_ext_dirty(handle, inode, path + depth);
2685 /* zero out the first half */
2686 /* blocks available from iblock */
2687 return allocated;
2688 }
2689 }
2690 /*
2691 * If there was a change of depth as part of the
2692 * insertion of ex3 above, we need to update the length
2693 * of the ex1 extent again here
2694 */
2695 if (ex1 && ex1 != ex) {
2696 ex1 = ex;
2697 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2698 ext4_ext_mark_uninitialized(ex1);
2699 ex2 = &newex;
2700 }
2701 /* ex2: iblock to iblock + maxblocks-1 : initialised */
2702 ex2->ee_block = cpu_to_le32(iblock);
2703 ext4_ext_store_pblock(ex2, newblock);
2704 ex2->ee_len = cpu_to_le16(allocated);
2705 if (ex2 != ex)
2706 goto insert;
2707 /*
2708 * New (initialized) extent starts from the first block
2709 * in the current extent. i.e., ex2 == ex
2710 * We have to see if it can be merged with the extent
2711 * on the left.
2712 */
2713 if (ex2 > EXT_FIRST_EXTENT(eh)) {
2714 /*
2715 * To merge left, pass "ex2 - 1" to try_to_merge(),
2716 * since it merges towards right _only_.
2717 */
2718 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
2719 if (ret) {
2720 err = ext4_ext_correct_indexes(handle, inode, path);
2721 if (err)
2722 goto out;
2723 depth = ext_depth(inode);
2724 ex2--;
2725 }
2726 }
2727 /*
2728 * Try to Merge towards right. This might be required
2729 * only when the whole extent is being written to.
2730 * i.e. ex2 == ex and ex3 == NULL.
2731 */
2732 if (!ex3) {
2733 ret = ext4_ext_try_to_merge(inode, path, ex2);
2734 if (ret) {
2735 err = ext4_ext_correct_indexes(handle, inode, path);
2736 if (err)
2737 goto out;
2738 }
2739 }
2740 /* Mark modified extent as dirty */
2741 err = ext4_ext_dirty(handle, inode, path + depth);
2742 goto out;
2743 insert:
2744 err = ext4_ext_insert_extent(handle, inode, path, &newex, 0);
2745 if (err == -ENOSPC) {
2746 err = ext4_ext_zeroout(inode, &orig_ex);
2747 if (err)
2748 goto fix_extent_len;
2749 /* update the extent length and mark as initialized */
2750 ex->ee_block = orig_ex.ee_block;
2751 ex->ee_len = orig_ex.ee_len;
2752 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2753 ext4_ext_dirty(handle, inode, path + depth);
2754 /* zero out the first half */
2755 return allocated;
2756 } else if (err)
2757 goto fix_extent_len;
2758 out:
2759 return err ? err : allocated;
2760
2761 fix_extent_len:
2762 ex->ee_block = orig_ex.ee_block;
2763 ex->ee_len = orig_ex.ee_len;
2764 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2765 ext4_ext_mark_uninitialized(ex);
2766 ext4_ext_dirty(handle, inode, path + depth);
2767 return err;
2768 }
2769
2770 /*
2771 * This function is called by ext4_ext_get_blocks() from
2772 * ext4_get_blocks_dio_write() when DIO to write
2773 * to an uninitialized extent.
2774 *
2775 * Writing to an uninitized extent may result in splitting the uninitialized
2776 * extent into multiple /intialized unintialized extents (up to three)
2777 * There are three possibilities:
2778 * a> There is no split required: Entire extent should be uninitialized
2779 * b> Splits in two extents: Write is happening at either end of the extent
2780 * c> Splits in three extents: Somone is writing in middle of the extent
2781 *
2782 * One of more index blocks maybe needed if the extent tree grow after
2783 * the unintialized extent split. To prevent ENOSPC occur at the IO
2784 * complete, we need to split the uninitialized extent before DIO submit
2785 * the IO. The uninitilized extent called at this time will be split
2786 * into three uninitialized extent(at most). After IO complete, the part
2787 * being filled will be convert to initialized by the end_io callback function
2788 * via ext4_convert_unwritten_extents().
2789 *
2790 * Returns the size of uninitialized extent to be written on success.
2791 */
2792 static int ext4_split_unwritten_extents(handle_t *handle,
2793 struct inode *inode,
2794 struct ext4_ext_path *path,
2795 ext4_lblk_t iblock,
2796 unsigned int max_blocks,
2797 int flags)
2798 {
2799 struct ext4_extent *ex, newex, orig_ex;
2800 struct ext4_extent *ex1 = NULL;
2801 struct ext4_extent *ex2 = NULL;
2802 struct ext4_extent *ex3 = NULL;
2803 struct ext4_extent_header *eh;
2804 ext4_lblk_t ee_block;
2805 unsigned int allocated, ee_len, depth;
2806 ext4_fsblk_t newblock;
2807 int err = 0;
2808
2809 ext_debug("ext4_split_unwritten_extents: inode %lu,"
2810 "iblock %llu, max_blocks %u\n", inode->i_ino,
2811 (unsigned long long)iblock, max_blocks);
2812 depth = ext_depth(inode);
2813 eh = path[depth].p_hdr;
2814 ex = path[depth].p_ext;
2815 ee_block = le32_to_cpu(ex->ee_block);
2816 ee_len = ext4_ext_get_actual_len(ex);
2817 allocated = ee_len - (iblock - ee_block);
2818 newblock = iblock - ee_block + ext_pblock(ex);
2819 ex2 = ex;
2820 orig_ex.ee_block = ex->ee_block;
2821 orig_ex.ee_len = cpu_to_le16(ee_len);
2822 ext4_ext_store_pblock(&orig_ex, ext_pblock(ex));
2823
2824 /*
2825 * If the uninitialized extent begins at the same logical
2826 * block where the write begins, and the write completely
2827 * covers the extent, then we don't need to split it.
2828 */
2829 if ((iblock == ee_block) && (allocated <= max_blocks))
2830 return allocated;
2831
2832 err = ext4_ext_get_access(handle, inode, path + depth);
2833 if (err)
2834 goto out;
2835 /* ex1: ee_block to iblock - 1 : uninitialized */
2836 if (iblock > ee_block) {
2837 ex1 = ex;
2838 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2839 ext4_ext_mark_uninitialized(ex1);
2840 ex2 = &newex;
2841 }
2842 /*
2843 * for sanity, update the length of the ex2 extent before
2844 * we insert ex3, if ex1 is NULL. This is to avoid temporary
2845 * overlap of blocks.
2846 */
2847 if (!ex1 && allocated > max_blocks)
2848 ex2->ee_len = cpu_to_le16(max_blocks);
2849 /* ex3: to ee_block + ee_len : uninitialised */
2850 if (allocated > max_blocks) {
2851 unsigned int newdepth;
2852 ex3 = &newex;
2853 ex3->ee_block = cpu_to_le32(iblock + max_blocks);
2854 ext4_ext_store_pblock(ex3, newblock + max_blocks);
2855 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
2856 ext4_ext_mark_uninitialized(ex3);
2857 err = ext4_ext_insert_extent(handle, inode, path, ex3, flags);
2858 if (err == -ENOSPC) {
2859 err = ext4_ext_zeroout(inode, &orig_ex);
2860 if (err)
2861 goto fix_extent_len;
2862 /* update the extent length and mark as initialized */
2863 ex->ee_block = orig_ex.ee_block;
2864 ex->ee_len = orig_ex.ee_len;
2865 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2866 ext4_ext_dirty(handle, inode, path + depth);
2867 /* zeroed the full extent */
2868 /* blocks available from iblock */
2869 return allocated;
2870
2871 } else if (err)
2872 goto fix_extent_len;
2873 /*
2874 * The depth, and hence eh & ex might change
2875 * as part of the insert above.
2876 */
2877 newdepth = ext_depth(inode);
2878 /*
2879 * update the extent length after successful insert of the
2880 * split extent
2881 */
2882 orig_ex.ee_len = cpu_to_le16(ee_len -
2883 ext4_ext_get_actual_len(ex3));
2884 depth = newdepth;
2885 ext4_ext_drop_refs(path);
2886 path = ext4_ext_find_extent(inode, iblock, path);
2887 if (IS_ERR(path)) {
2888 err = PTR_ERR(path);
2889 goto out;
2890 }
2891 eh = path[depth].p_hdr;
2892 ex = path[depth].p_ext;
2893 if (ex2 != &newex)
2894 ex2 = ex;
2895
2896 err = ext4_ext_get_access(handle, inode, path + depth);
2897 if (err)
2898 goto out;
2899
2900 allocated = max_blocks;
2901 }
2902 /*
2903 * If there was a change of depth as part of the
2904 * insertion of ex3 above, we need to update the length
2905 * of the ex1 extent again here
2906 */
2907 if (ex1 && ex1 != ex) {
2908 ex1 = ex;
2909 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2910 ext4_ext_mark_uninitialized(ex1);
2911 ex2 = &newex;
2912 }
2913 /*
2914 * ex2: iblock to iblock + maxblocks-1 : to be direct IO written,
2915 * uninitialised still.
2916 */
2917 ex2->ee_block = cpu_to_le32(iblock);
2918 ext4_ext_store_pblock(ex2, newblock);
2919 ex2->ee_len = cpu_to_le16(allocated);
2920 ext4_ext_mark_uninitialized(ex2);
2921 if (ex2 != ex)
2922 goto insert;
2923 /* Mark modified extent as dirty */
2924 err = ext4_ext_dirty(handle, inode, path + depth);
2925 ext_debug("out here\n");
2926 goto out;
2927 insert:
2928 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2929 if (err == -ENOSPC) {
2930 err = ext4_ext_zeroout(inode, &orig_ex);
2931 if (err)
2932 goto fix_extent_len;
2933 /* update the extent length and mark as initialized */
2934 ex->ee_block = orig_ex.ee_block;
2935 ex->ee_len = orig_ex.ee_len;
2936 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2937 ext4_ext_dirty(handle, inode, path + depth);
2938 /* zero out the first half */
2939 return allocated;
2940 } else if (err)
2941 goto fix_extent_len;
2942 out:
2943 ext4_ext_show_leaf(inode, path);
2944 return err ? err : allocated;
2945
2946 fix_extent_len:
2947 ex->ee_block = orig_ex.ee_block;
2948 ex->ee_len = orig_ex.ee_len;
2949 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2950 ext4_ext_mark_uninitialized(ex);
2951 ext4_ext_dirty(handle, inode, path + depth);
2952 return err;
2953 }
2954 static int ext4_convert_unwritten_extents_dio(handle_t *handle,
2955 struct inode *inode,
2956 struct ext4_ext_path *path)
2957 {
2958 struct ext4_extent *ex;
2959 struct ext4_extent_header *eh;
2960 int depth;
2961 int err = 0;
2962 int ret = 0;
2963
2964 depth = ext_depth(inode);
2965 eh = path[depth].p_hdr;
2966 ex = path[depth].p_ext;
2967
2968 err = ext4_ext_get_access(handle, inode, path + depth);
2969 if (err)
2970 goto out;
2971 /* first mark the extent as initialized */
2972 ext4_ext_mark_initialized(ex);
2973
2974 /*
2975 * We have to see if it can be merged with the extent
2976 * on the left.
2977 */
2978 if (ex > EXT_FIRST_EXTENT(eh)) {
2979 /*
2980 * To merge left, pass "ex - 1" to try_to_merge(),
2981 * since it merges towards right _only_.
2982 */
2983 ret = ext4_ext_try_to_merge(inode, path, ex - 1);
2984 if (ret) {
2985 err = ext4_ext_correct_indexes(handle, inode, path);
2986 if (err)
2987 goto out;
2988 depth = ext_depth(inode);
2989 ex--;
2990 }
2991 }
2992 /*
2993 * Try to Merge towards right.
2994 */
2995 ret = ext4_ext_try_to_merge(inode, path, ex);
2996 if (ret) {
2997 err = ext4_ext_correct_indexes(handle, inode, path);
2998 if (err)
2999 goto out;
3000 depth = ext_depth(inode);
3001 }
3002 /* Mark modified extent as dirty */
3003 err = ext4_ext_dirty(handle, inode, path + depth);
3004 out:
3005 ext4_ext_show_leaf(inode, path);
3006 return err;
3007 }
3008
3009 static int
3010 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3011 ext4_lblk_t iblock, unsigned int max_blocks,
3012 struct ext4_ext_path *path, int flags,
3013 unsigned int allocated, struct buffer_head *bh_result,
3014 ext4_fsblk_t newblock)
3015 {
3016 int ret = 0;
3017 int err = 0;
3018 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3019
3020 ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
3021 "block %llu, max_blocks %u, flags %d, allocated %u",
3022 inode->i_ino, (unsigned long long)iblock, max_blocks,
3023 flags, allocated);
3024 ext4_ext_show_leaf(inode, path);
3025
3026 /* DIO get_block() before submit the IO, split the extent */
3027 if (flags == EXT4_GET_BLOCKS_DIO_CREATE_EXT) {
3028 ret = ext4_split_unwritten_extents(handle,
3029 inode, path, iblock,
3030 max_blocks, flags);
3031 /*
3032 * Flag the inode(non aio case) or end_io struct (aio case)
3033 * that this IO needs to convertion to written when IO is
3034 * completed
3035 */
3036 if (io)
3037 io->flag = DIO_AIO_UNWRITTEN;
3038 else
3039 EXT4_I(inode)->i_state |= EXT4_STATE_DIO_UNWRITTEN;
3040 goto out;
3041 }
3042 /* async DIO end_io complete, convert the filled extent to written */
3043 if (flags == EXT4_GET_BLOCKS_DIO_CONVERT_EXT) {
3044 ret = ext4_convert_unwritten_extents_dio(handle, inode,
3045 path);
3046 if (ret >= 0)
3047 ext4_update_inode_fsync_trans(handle, inode, 1);
3048 goto out2;
3049 }
3050 /* buffered IO case */
3051 /*
3052 * repeat fallocate creation request
3053 * we already have an unwritten extent
3054 */
3055 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
3056 goto map_out;
3057
3058 /* buffered READ or buffered write_begin() lookup */
3059 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3060 /*
3061 * We have blocks reserved already. We
3062 * return allocated blocks so that delalloc
3063 * won't do block reservation for us. But
3064 * the buffer head will be unmapped so that
3065 * a read from the block returns 0s.
3066 */
3067 set_buffer_unwritten(bh_result);
3068 goto out1;
3069 }
3070
3071 /* buffered write, writepage time, convert*/
3072 ret = ext4_ext_convert_to_initialized(handle, inode,
3073 path, iblock,
3074 max_blocks);
3075 if (ret >= 0)
3076 ext4_update_inode_fsync_trans(handle, inode, 1);
3077 out:
3078 if (ret <= 0) {
3079 err = ret;
3080 goto out2;
3081 } else
3082 allocated = ret;
3083 set_buffer_new(bh_result);
3084 map_out:
3085 set_buffer_mapped(bh_result);
3086 out1:
3087 if (allocated > max_blocks)
3088 allocated = max_blocks;
3089 ext4_ext_show_leaf(inode, path);
3090 bh_result->b_bdev = inode->i_sb->s_bdev;
3091 bh_result->b_blocknr = newblock;
3092 out2:
3093 if (path) {
3094 ext4_ext_drop_refs(path);
3095 kfree(path);
3096 }
3097 return err ? err : allocated;
3098 }
3099 /*
3100 * Block allocation/map/preallocation routine for extents based files
3101 *
3102 *
3103 * Need to be called with
3104 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3105 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3106 *
3107 * return > 0, number of of blocks already mapped/allocated
3108 * if create == 0 and these are pre-allocated blocks
3109 * buffer head is unmapped
3110 * otherwise blocks are mapped
3111 *
3112 * return = 0, if plain look up failed (blocks have not been allocated)
3113 * buffer head is unmapped
3114 *
3115 * return < 0, error case.
3116 */
3117 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
3118 ext4_lblk_t iblock,
3119 unsigned int max_blocks, struct buffer_head *bh_result,
3120 int flags)
3121 {
3122 struct ext4_ext_path *path = NULL;
3123 struct ext4_extent_header *eh;
3124 struct ext4_extent newex, *ex;
3125 ext4_fsblk_t newblock;
3126 int err = 0, depth, ret, cache_type;
3127 unsigned int allocated = 0;
3128 struct ext4_allocation_request ar;
3129 ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3130
3131 __clear_bit(BH_New, &bh_result->b_state);
3132 ext_debug("blocks %u/%u requested for inode %u\n",
3133 iblock, max_blocks, inode->i_ino);
3134
3135 /* check in cache */
3136 cache_type = ext4_ext_in_cache(inode, iblock, &newex);
3137 if (cache_type) {
3138 if (cache_type == EXT4_EXT_CACHE_GAP) {
3139 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3140 /*
3141 * block isn't allocated yet and
3142 * user doesn't want to allocate it
3143 */
3144 goto out2;
3145 }
3146 /* we should allocate requested block */
3147 } else if (cache_type == EXT4_EXT_CACHE_EXTENT) {
3148 /* block is already allocated */
3149 newblock = iblock
3150 - le32_to_cpu(newex.ee_block)
3151 + ext_pblock(&newex);
3152 /* number of remaining blocks in the extent */
3153 allocated = ext4_ext_get_actual_len(&newex) -
3154 (iblock - le32_to_cpu(newex.ee_block));
3155 goto out;
3156 } else {
3157 BUG();
3158 }
3159 }
3160
3161 /* find extent for this block */
3162 path = ext4_ext_find_extent(inode, iblock, NULL);
3163 if (IS_ERR(path)) {
3164 err = PTR_ERR(path);
3165 path = NULL;
3166 goto out2;
3167 }
3168
3169 depth = ext_depth(inode);
3170
3171 /*
3172 * consistent leaf must not be empty;
3173 * this situation is possible, though, _during_ tree modification;
3174 * this is why assert can't be put in ext4_ext_find_extent()
3175 */
3176 BUG_ON(path[depth].p_ext == NULL && depth != 0);
3177 eh = path[depth].p_hdr;
3178
3179 ex = path[depth].p_ext;
3180 if (ex) {
3181 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3182 ext4_fsblk_t ee_start = ext_pblock(ex);
3183 unsigned short ee_len;
3184
3185 /*
3186 * Uninitialized extents are treated as holes, except that
3187 * we split out initialized portions during a write.
3188 */
3189 ee_len = ext4_ext_get_actual_len(ex);
3190 /* if found extent covers block, simply return it */
3191 if (iblock >= ee_block && iblock < ee_block + ee_len) {
3192 newblock = iblock - ee_block + ee_start;
3193 /* number of remaining blocks in the extent */
3194 allocated = ee_len - (iblock - ee_block);
3195 ext_debug("%u fit into %lu:%d -> %llu\n", iblock,
3196 ee_block, ee_len, newblock);
3197
3198 /* Do not put uninitialized extent in the cache */
3199 if (!ext4_ext_is_uninitialized(ex)) {
3200 ext4_ext_put_in_cache(inode, ee_block,
3201 ee_len, ee_start,
3202 EXT4_EXT_CACHE_EXTENT);
3203 goto out;
3204 }
3205 ret = ext4_ext_handle_uninitialized_extents(handle,
3206 inode, iblock, max_blocks, path,
3207 flags, allocated, bh_result, newblock);
3208 return ret;
3209 }
3210 }
3211
3212 /*
3213 * requested block isn't allocated yet;
3214 * we couldn't try to create block if create flag is zero
3215 */
3216 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3217 /*
3218 * put just found gap into cache to speed up
3219 * subsequent requests
3220 */
3221 ext4_ext_put_gap_in_cache(inode, path, iblock);
3222 goto out2;
3223 }
3224 /*
3225 * Okay, we need to do block allocation.
3226 */
3227
3228 /* find neighbour allocated blocks */
3229 ar.lleft = iblock;
3230 err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3231 if (err)
3232 goto out2;
3233 ar.lright = iblock;
3234 err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
3235 if (err)
3236 goto out2;
3237
3238 /*
3239 * See if request is beyond maximum number of blocks we can have in
3240 * a single extent. For an initialized extent this limit is
3241 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
3242 * EXT_UNINIT_MAX_LEN.
3243 */
3244 if (max_blocks > EXT_INIT_MAX_LEN &&
3245 !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3246 max_blocks = EXT_INIT_MAX_LEN;
3247 else if (max_blocks > EXT_UNINIT_MAX_LEN &&
3248 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3249 max_blocks = EXT_UNINIT_MAX_LEN;
3250
3251 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
3252 newex.ee_block = cpu_to_le32(iblock);
3253 newex.ee_len = cpu_to_le16(max_blocks);
3254 err = ext4_ext_check_overlap(inode, &newex, path);
3255 if (err)
3256 allocated = ext4_ext_get_actual_len(&newex);
3257 else
3258 allocated = max_blocks;
3259
3260 /* allocate new block */
3261 ar.inode = inode;
3262 ar.goal = ext4_ext_find_goal(inode, path, iblock);
3263 ar.logical = iblock;
3264 ar.len = allocated;
3265 if (S_ISREG(inode->i_mode))
3266 ar.flags = EXT4_MB_HINT_DATA;
3267 else
3268 /* disable in-core preallocation for non-regular files */
3269 ar.flags = 0;
3270 newblock = ext4_mb_new_blocks(handle, &ar, &err);
3271 if (!newblock)
3272 goto out2;
3273 ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
3274 ar.goal, newblock, allocated);
3275
3276 /* try to insert new extent into found leaf and return */
3277 ext4_ext_store_pblock(&newex, newblock);
3278 newex.ee_len = cpu_to_le16(ar.len);
3279 /* Mark uninitialized */
3280 if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
3281 ext4_ext_mark_uninitialized(&newex);
3282 /*
3283 * io_end structure was created for every async
3284 * direct IO write to the middle of the file.
3285 * To avoid unecessary convertion for every aio dio rewrite
3286 * to the mid of file, here we flag the IO that is really
3287 * need the convertion.
3288 * For non asycn direct IO case, flag the inode state
3289 * that we need to perform convertion when IO is done.
3290 */
3291 if (flags == EXT4_GET_BLOCKS_DIO_CREATE_EXT) {
3292 if (io)
3293 io->flag = DIO_AIO_UNWRITTEN;
3294 else
3295 EXT4_I(inode)->i_state |=
3296 EXT4_STATE_DIO_UNWRITTEN;;
3297 }
3298 }
3299 err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
3300 if (err) {
3301 /* free data blocks we just allocated */
3302 /* not a good idea to call discard here directly,
3303 * but otherwise we'd need to call it every free() */
3304 ext4_discard_preallocations(inode);
3305 ext4_free_blocks(handle, inode, ext_pblock(&newex),
3306 ext4_ext_get_actual_len(&newex), 0);
3307 goto out2;
3308 }
3309
3310 /* previous routine could use block we allocated */
3311 newblock = ext_pblock(&newex);
3312 allocated = ext4_ext_get_actual_len(&newex);
3313 set_buffer_new(bh_result);
3314
3315 /*
3316 * Cache the extent and update transaction to commit on fdatasync only
3317 * when it is _not_ an uninitialized extent.
3318 */
3319 if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
3320 ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
3321 EXT4_EXT_CACHE_EXTENT);
3322 ext4_update_inode_fsync_trans(handle, inode, 1);
3323 } else
3324 ext4_update_inode_fsync_trans(handle, inode, 0);
3325 out:
3326 if (allocated > max_blocks)
3327 allocated = max_blocks;
3328 ext4_ext_show_leaf(inode, path);
3329 set_buffer_mapped(bh_result);
3330 bh_result->b_bdev = inode->i_sb->s_bdev;
3331 bh_result->b_blocknr = newblock;
3332 out2:
3333 if (path) {
3334 ext4_ext_drop_refs(path);
3335 kfree(path);
3336 }
3337 return err ? err : allocated;
3338 }
3339
3340 void ext4_ext_truncate(struct inode *inode)
3341 {
3342 struct address_space *mapping = inode->i_mapping;
3343 struct super_block *sb = inode->i_sb;
3344 ext4_lblk_t last_block;
3345 handle_t *handle;
3346 int err = 0;
3347
3348 /*
3349 * probably first extent we're gonna free will be last in block
3350 */
3351 err = ext4_writepage_trans_blocks(inode);
3352 handle = ext4_journal_start(inode, err);
3353 if (IS_ERR(handle))
3354 return;
3355
3356 if (inode->i_size & (sb->s_blocksize - 1))
3357 ext4_block_truncate_page(handle, mapping, inode->i_size);
3358
3359 if (ext4_orphan_add(handle, inode))
3360 goto out_stop;
3361
3362 down_write(&EXT4_I(inode)->i_data_sem);
3363 ext4_ext_invalidate_cache(inode);
3364
3365 ext4_discard_preallocations(inode);
3366
3367 /*
3368 * TODO: optimization is possible here.
3369 * Probably we need not scan at all,
3370 * because page truncation is enough.
3371 */
3372
3373 /* we have to know where to truncate from in crash case */
3374 EXT4_I(inode)->i_disksize = inode->i_size;
3375 ext4_mark_inode_dirty(handle, inode);
3376
3377 last_block = (inode->i_size + sb->s_blocksize - 1)
3378 >> EXT4_BLOCK_SIZE_BITS(sb);
3379 err = ext4_ext_remove_space(inode, last_block);
3380
3381 /* In a multi-transaction truncate, we only make the final
3382 * transaction synchronous.
3383 */
3384 if (IS_SYNC(inode))
3385 ext4_handle_sync(handle);
3386
3387 out_stop:
3388 up_write(&EXT4_I(inode)->i_data_sem);
3389 /*
3390 * If this was a simple ftruncate() and the file will remain alive,
3391 * then we need to clear up the orphan record which we created above.
3392 * However, if this was a real unlink then we were called by
3393 * ext4_delete_inode(), and we allow that function to clean up the
3394 * orphan info for us.
3395 */
3396 if (inode->i_nlink)
3397 ext4_orphan_del(handle, inode);
3398
3399 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3400 ext4_mark_inode_dirty(handle, inode);
3401 ext4_journal_stop(handle);
3402 }
3403
3404 static void ext4_falloc_update_inode(struct inode *inode,
3405 int mode, loff_t new_size, int update_ctime)
3406 {
3407 struct timespec now;
3408
3409 if (update_ctime) {
3410 now = current_fs_time(inode->i_sb);
3411 if (!timespec_equal(&inode->i_ctime, &now))
3412 inode->i_ctime = now;
3413 }
3414 /*
3415 * Update only when preallocation was requested beyond
3416 * the file size.
3417 */
3418 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3419 if (new_size > i_size_read(inode))
3420 i_size_write(inode, new_size);
3421 if (new_size > EXT4_I(inode)->i_disksize)
3422 ext4_update_i_disksize(inode, new_size);
3423 }
3424
3425 }
3426
3427 /*
3428 * preallocate space for a file. This implements ext4's fallocate inode
3429 * operation, which gets called from sys_fallocate system call.
3430 * For block-mapped files, posix_fallocate should fall back to the method
3431 * of writing zeroes to the required new blocks (the same behavior which is
3432 * expected for file systems which do not support fallocate() system call).
3433 */
3434 long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
3435 {
3436 handle_t *handle;
3437 ext4_lblk_t block;
3438 loff_t new_size;
3439 unsigned int max_blocks;
3440 int ret = 0;
3441 int ret2 = 0;
3442 int retries = 0;
3443 struct buffer_head map_bh;
3444 unsigned int credits, blkbits = inode->i_blkbits;
3445
3446 /*
3447 * currently supporting (pre)allocate mode for extent-based
3448 * files _only_
3449 */
3450 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
3451 return -EOPNOTSUPP;
3452
3453 /* preallocation to directories is currently not supported */
3454 if (S_ISDIR(inode->i_mode))
3455 return -ENODEV;
3456
3457 block = offset >> blkbits;
3458 /*
3459 * We can't just convert len to max_blocks because
3460 * If blocksize = 4096 offset = 3072 and len = 2048
3461 */
3462 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3463 - block;
3464 /*
3465 * credits to insert 1 extent into extent tree
3466 */
3467 credits = ext4_chunk_trans_blocks(inode, max_blocks);
3468 mutex_lock(&inode->i_mutex);
3469 retry:
3470 while (ret >= 0 && ret < max_blocks) {
3471 block = block + ret;
3472 max_blocks = max_blocks - ret;
3473 handle = ext4_journal_start(inode, credits);
3474 if (IS_ERR(handle)) {
3475 ret = PTR_ERR(handle);
3476 break;
3477 }
3478 map_bh.b_state = 0;
3479 ret = ext4_get_blocks(handle, inode, block,
3480 max_blocks, &map_bh,
3481 EXT4_GET_BLOCKS_CREATE_UNINIT_EXT);
3482 if (ret <= 0) {
3483 #ifdef EXT4FS_DEBUG
3484 WARN_ON(ret <= 0);
3485 printk(KERN_ERR "%s: ext4_ext_get_blocks "
3486 "returned error inode#%lu, block=%u, "
3487 "max_blocks=%u", __func__,
3488 inode->i_ino, block, max_blocks);
3489 #endif
3490 ext4_mark_inode_dirty(handle, inode);
3491 ret2 = ext4_journal_stop(handle);
3492 break;
3493 }
3494 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
3495 blkbits) >> blkbits))
3496 new_size = offset + len;
3497 else
3498 new_size = (block + ret) << blkbits;
3499
3500 ext4_falloc_update_inode(inode, mode, new_size,
3501 buffer_new(&map_bh));
3502 ext4_mark_inode_dirty(handle, inode);
3503 ret2 = ext4_journal_stop(handle);
3504 if (ret2)
3505 break;
3506 }
3507 if (ret == -ENOSPC &&
3508 ext4_should_retry_alloc(inode->i_sb, &retries)) {
3509 ret = 0;
3510 goto retry;
3511 }
3512 mutex_unlock(&inode->i_mutex);
3513 return ret > 0 ? ret2 : ret;
3514 }
3515
3516 /*
3517 * This function convert a range of blocks to written extents
3518 * The caller of this function will pass the start offset and the size.
3519 * all unwritten extents within this range will be converted to
3520 * written extents.
3521 *
3522 * This function is called from the direct IO end io call back
3523 * function, to convert the fallocated extents after IO is completed.
3524 * Returns 0 on success.
3525 */
3526 int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
3527 loff_t len)
3528 {
3529 handle_t *handle;
3530 ext4_lblk_t block;
3531 unsigned int max_blocks;
3532 int ret = 0;
3533 int ret2 = 0;
3534 struct buffer_head map_bh;
3535 unsigned int credits, blkbits = inode->i_blkbits;
3536
3537 block = offset >> blkbits;
3538 /*
3539 * We can't just convert len to max_blocks because
3540 * If blocksize = 4096 offset = 3072 and len = 2048
3541 */
3542 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3543 - block;
3544 /*
3545 * credits to insert 1 extent into extent tree
3546 */
3547 credits = ext4_chunk_trans_blocks(inode, max_blocks);
3548 while (ret >= 0 && ret < max_blocks) {
3549 block = block + ret;
3550 max_blocks = max_blocks - ret;
3551 handle = ext4_journal_start(inode, credits);
3552 if (IS_ERR(handle)) {
3553 ret = PTR_ERR(handle);
3554 break;
3555 }
3556 map_bh.b_state = 0;
3557 ret = ext4_get_blocks(handle, inode, block,
3558 max_blocks, &map_bh,
3559 EXT4_GET_BLOCKS_DIO_CONVERT_EXT);
3560 if (ret <= 0) {
3561 WARN_ON(ret <= 0);
3562 printk(KERN_ERR "%s: ext4_ext_get_blocks "
3563 "returned error inode#%lu, block=%u, "
3564 "max_blocks=%u", __func__,
3565 inode->i_ino, block, max_blocks);
3566 }
3567 ext4_mark_inode_dirty(handle, inode);
3568 ret2 = ext4_journal_stop(handle);
3569 if (ret <= 0 || ret2 )
3570 break;
3571 }
3572 return ret > 0 ? ret2 : ret;
3573 }
3574 /*
3575 * Callback function called for each extent to gather FIEMAP information.
3576 */
3577 static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path,
3578 struct ext4_ext_cache *newex, struct ext4_extent *ex,
3579 void *data)
3580 {
3581 struct fiemap_extent_info *fieinfo = data;
3582 unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
3583 __u64 logical;
3584 __u64 physical;
3585 __u64 length;
3586 __u32 flags = 0;
3587 int error;
3588
3589 logical = (__u64)newex->ec_block << blksize_bits;
3590
3591 if (newex->ec_type == EXT4_EXT_CACHE_GAP) {
3592 pgoff_t offset;
3593 struct page *page;
3594 struct buffer_head *bh = NULL;
3595
3596 offset = logical >> PAGE_SHIFT;
3597 page = find_get_page(inode->i_mapping, offset);
3598 if (!page || !page_has_buffers(page))
3599 return EXT_CONTINUE;
3600
3601 bh = page_buffers(page);
3602
3603 if (!bh)
3604 return EXT_CONTINUE;
3605
3606 if (buffer_delay(bh)) {
3607 flags |= FIEMAP_EXTENT_DELALLOC;
3608 page_cache_release(page);
3609 } else {
3610 page_cache_release(page);
3611 return EXT_CONTINUE;
3612 }
3613 }
3614
3615 physical = (__u64)newex->ec_start << blksize_bits;
3616 length = (__u64)newex->ec_len << blksize_bits;
3617
3618 if (ex && ext4_ext_is_uninitialized(ex))
3619 flags |= FIEMAP_EXTENT_UNWRITTEN;
3620
3621 /*
3622 * If this extent reaches EXT_MAX_BLOCK, it must be last.
3623 *
3624 * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK,
3625 * this also indicates no more allocated blocks.
3626 *
3627 * XXX this might miss a single-block extent at EXT_MAX_BLOCK
3628 */
3629 if (ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK ||
3630 newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK) {
3631 loff_t size = i_size_read(inode);
3632 loff_t bs = EXT4_BLOCK_SIZE(inode->i_sb);
3633
3634 flags |= FIEMAP_EXTENT_LAST;
3635 if ((flags & FIEMAP_EXTENT_DELALLOC) &&
3636 logical+length > size)
3637 length = (size - logical + bs - 1) & ~(bs-1);
3638 }
3639
3640 error = fiemap_fill_next_extent(fieinfo, logical, physical,
3641 length, flags);
3642 if (error < 0)
3643 return error;
3644 if (error == 1)
3645 return EXT_BREAK;
3646
3647 return EXT_CONTINUE;
3648 }
3649
3650 /* fiemap flags we can handle specified here */
3651 #define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
3652
3653 static int ext4_xattr_fiemap(struct inode *inode,
3654 struct fiemap_extent_info *fieinfo)
3655 {
3656 __u64 physical = 0;
3657 __u64 length;
3658 __u32 flags = FIEMAP_EXTENT_LAST;
3659 int blockbits = inode->i_sb->s_blocksize_bits;
3660 int error = 0;
3661
3662 /* in-inode? */
3663 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
3664 struct ext4_iloc iloc;
3665 int offset; /* offset of xattr in inode */
3666
3667 error = ext4_get_inode_loc(inode, &iloc);
3668 if (error)
3669 return error;
3670 physical = iloc.bh->b_blocknr << blockbits;
3671 offset = EXT4_GOOD_OLD_INODE_SIZE +
3672 EXT4_I(inode)->i_extra_isize;
3673 physical += offset;
3674 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
3675 flags |= FIEMAP_EXTENT_DATA_INLINE;
3676 } else { /* external block */
3677 physical = EXT4_I(inode)->i_file_acl << blockbits;
3678 length = inode->i_sb->s_blocksize;
3679 }
3680
3681 if (physical)
3682 error = fiemap_fill_next_extent(fieinfo, 0, physical,
3683 length, flags);
3684 return (error < 0 ? error : 0);
3685 }
3686
3687 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
3688 __u64 start, __u64 len)
3689 {
3690 ext4_lblk_t start_blk;
3691 ext4_lblk_t len_blks;
3692 int error = 0;
3693
3694 /* fallback to generic here if not in extents fmt */
3695 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
3696 return generic_block_fiemap(inode, fieinfo, start, len,
3697 ext4_get_block);
3698
3699 if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
3700 return -EBADR;
3701
3702 if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
3703 error = ext4_xattr_fiemap(inode, fieinfo);
3704 } else {
3705 start_blk = start >> inode->i_sb->s_blocksize_bits;
3706 len_blks = len >> inode->i_sb->s_blocksize_bits;
3707
3708 /*
3709 * Walk the extent tree gathering extent information.
3710 * ext4_ext_fiemap_cb will push extents back to user.
3711 */
3712 error = ext4_ext_walk_space(inode, start_blk, len_blks,
3713 ext4_ext_fiemap_cb, fieinfo);
3714 }
3715
3716 return error;
3717 }
3718
3719
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