headers: taskstats_kern.h trim
[linux-2.6.git] / fs / ext4 / extents.c
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_journal_restart(handle_t *handle, int needed)
97 {
98         int err;
99
100         if (!ext4_handle_valid(handle))
101                 return 0;
102         if (handle->h_buffer_credits > needed)
103                 return 0;
104         err = ext4_journal_extend(handle, needed);
105         if (err <= 0)
106                 return err;
107         return ext4_journal_restart(handle, needed);
108 }
109
110 /*
111  * could return:
112  *  - EROFS
113  *  - ENOMEM
114  */
115 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
116                                 struct ext4_ext_path *path)
117 {
118         if (path->p_bh) {
119                 /* path points to block */
120                 return ext4_journal_get_write_access(handle, path->p_bh);
121         }
122         /* path points to leaf/index in inode body */
123         /* we use in-core data, no need to protect them */
124         return 0;
125 }
126
127 /*
128  * could return:
129  *  - EROFS
130  *  - ENOMEM
131  *  - EIO
132  */
133 static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
134                                 struct ext4_ext_path *path)
135 {
136         int err;
137         if (path->p_bh) {
138                 /* path points to block */
139                 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
140         } else {
141                 /* path points to leaf/index in inode body */
142                 err = ext4_mark_inode_dirty(handle, inode);
143         }
144         return err;
145 }
146
147 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
148                               struct ext4_ext_path *path,
149                               ext4_lblk_t block)
150 {
151         struct ext4_inode_info *ei = EXT4_I(inode);
152         ext4_fsblk_t bg_start;
153         ext4_fsblk_t last_block;
154         ext4_grpblk_t colour;
155         ext4_group_t block_group;
156         int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
157         int depth;
158
159         if (path) {
160                 struct ext4_extent *ex;
161                 depth = path->p_depth;
162
163                 /* try to predict block placement */
164                 ex = path[depth].p_ext;
165                 if (ex)
166                         return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
167
168                 /* it looks like index is empty;
169                  * try to find starting block from index itself */
170                 if (path[depth].p_bh)
171                         return path[depth].p_bh->b_blocknr;
172         }
173
174         /* OK. use inode's group */
175         block_group = ei->i_block_group;
176         if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
177                 /*
178                  * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
179                  * block groups per flexgroup, reserve the first block 
180                  * group for directories and special files.  Regular 
181                  * files will start at the second block group.  This
182                  * tends to speed up directory access and improves 
183                  * fsck times.
184                  */
185                 block_group &= ~(flex_size-1);
186                 if (S_ISREG(inode->i_mode))
187                         block_group++;
188         }
189         bg_start = (block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
190                 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
191         last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
192
193         /*
194          * If we are doing delayed allocation, we don't need take
195          * colour into account.
196          */
197         if (test_opt(inode->i_sb, DELALLOC))
198                 return bg_start;
199
200         if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
201                 colour = (current->pid % 16) *
202                         (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
203         else
204                 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
205         return bg_start + colour + block;
206 }
207
208 /*
209  * Allocation for a meta data block
210  */
211 static ext4_fsblk_t
212 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
213                         struct ext4_ext_path *path,
214                         struct ext4_extent *ex, int *err)
215 {
216         ext4_fsblk_t goal, newblock;
217
218         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
219         newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
220         return newblock;
221 }
222
223 static int ext4_ext_space_block(struct inode *inode)
224 {
225         int size;
226
227         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
228                         / sizeof(struct ext4_extent);
229 #ifdef AGGRESSIVE_TEST
230         if (size > 6)
231                 size = 6;
232 #endif
233         return size;
234 }
235
236 static int ext4_ext_space_block_idx(struct inode *inode)
237 {
238         int size;
239
240         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
241                         / sizeof(struct ext4_extent_idx);
242 #ifdef AGGRESSIVE_TEST
243         if (size > 5)
244                 size = 5;
245 #endif
246         return size;
247 }
248
249 static int ext4_ext_space_root(struct inode *inode)
250 {
251         int size;
252
253         size = sizeof(EXT4_I(inode)->i_data);
254         size -= sizeof(struct ext4_extent_header);
255         size /= sizeof(struct ext4_extent);
256 #ifdef AGGRESSIVE_TEST
257         if (size > 3)
258                 size = 3;
259 #endif
260         return size;
261 }
262
263 static int ext4_ext_space_root_idx(struct inode *inode)
264 {
265         int size;
266
267         size = sizeof(EXT4_I(inode)->i_data);
268         size -= sizeof(struct ext4_extent_header);
269         size /= sizeof(struct ext4_extent_idx);
270 #ifdef AGGRESSIVE_TEST
271         if (size > 4)
272                 size = 4;
273 #endif
274         return size;
275 }
276
277 /*
278  * Calculate the number of metadata blocks needed
279  * to allocate @blocks
280  * Worse case is one block per extent
281  */
282 int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks)
283 {
284         int lcap, icap, rcap, leafs, idxs, num;
285         int newextents = blocks;
286
287         rcap = ext4_ext_space_root_idx(inode);
288         lcap = ext4_ext_space_block(inode);
289         icap = ext4_ext_space_block_idx(inode);
290
291         /* number of new leaf blocks needed */
292         num = leafs = (newextents + lcap - 1) / lcap;
293
294         /*
295          * Worse case, we need separate index block(s)
296          * to link all new leaf blocks
297          */
298         idxs = (leafs + icap - 1) / icap;
299         do {
300                 num += idxs;
301                 idxs = (idxs + icap - 1) / icap;
302         } while (idxs > rcap);
303
304         return num;
305 }
306
307 static int
308 ext4_ext_max_entries(struct inode *inode, int depth)
309 {
310         int max;
311
312         if (depth == ext_depth(inode)) {
313                 if (depth == 0)
314                         max = ext4_ext_space_root(inode);
315                 else
316                         max = ext4_ext_space_root_idx(inode);
317         } else {
318                 if (depth == 0)
319                         max = ext4_ext_space_block(inode);
320                 else
321                         max = ext4_ext_space_block_idx(inode);
322         }
323
324         return max;
325 }
326
327 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
328 {
329         ext4_fsblk_t block = ext_pblock(ext);
330         int len = ext4_ext_get_actual_len(ext);
331
332         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
333 }
334
335 static int ext4_valid_extent_idx(struct inode *inode,
336                                 struct ext4_extent_idx *ext_idx)
337 {
338         ext4_fsblk_t block = idx_pblock(ext_idx);
339
340         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
341 }
342
343 static int ext4_valid_extent_entries(struct inode *inode,
344                                 struct ext4_extent_header *eh,
345                                 int depth)
346 {
347         struct ext4_extent *ext;
348         struct ext4_extent_idx *ext_idx;
349         unsigned short entries;
350         if (eh->eh_entries == 0)
351                 return 1;
352
353         entries = le16_to_cpu(eh->eh_entries);
354
355         if (depth == 0) {
356                 /* leaf entries */
357                 ext = EXT_FIRST_EXTENT(eh);
358                 while (entries) {
359                         if (!ext4_valid_extent(inode, ext))
360                                 return 0;
361                         ext++;
362                         entries--;
363                 }
364         } else {
365                 ext_idx = EXT_FIRST_INDEX(eh);
366                 while (entries) {
367                         if (!ext4_valid_extent_idx(inode, ext_idx))
368                                 return 0;
369                         ext_idx++;
370                         entries--;
371                 }
372         }
373         return 1;
374 }
375
376 static int __ext4_ext_check(const char *function, struct inode *inode,
377                                         struct ext4_extent_header *eh,
378                                         int depth)
379 {
380         const char *error_msg;
381         int max = 0;
382
383         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
384                 error_msg = "invalid magic";
385                 goto corrupted;
386         }
387         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
388                 error_msg = "unexpected eh_depth";
389                 goto corrupted;
390         }
391         if (unlikely(eh->eh_max == 0)) {
392                 error_msg = "invalid eh_max";
393                 goto corrupted;
394         }
395         max = ext4_ext_max_entries(inode, depth);
396         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
397                 error_msg = "too large eh_max";
398                 goto corrupted;
399         }
400         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
401                 error_msg = "invalid eh_entries";
402                 goto corrupted;
403         }
404         if (!ext4_valid_extent_entries(inode, eh, depth)) {
405                 error_msg = "invalid extent entries";
406                 goto corrupted;
407         }
408         return 0;
409
410 corrupted:
411         ext4_error(inode->i_sb, function,
412                         "bad header/extent in inode #%lu: %s - magic %x, "
413                         "entries %u, max %u(%u), depth %u(%u)",
414                         inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
415                         le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
416                         max, le16_to_cpu(eh->eh_depth), depth);
417
418         return -EIO;
419 }
420
421 #define ext4_ext_check(inode, eh, depth)        \
422         __ext4_ext_check(__func__, inode, eh, depth)
423
424 int ext4_ext_check_inode(struct inode *inode)
425 {
426         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
427 }
428
429 #ifdef EXT_DEBUG
430 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
431 {
432         int k, l = path->p_depth;
433
434         ext_debug("path:");
435         for (k = 0; k <= l; k++, path++) {
436                 if (path->p_idx) {
437                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
438                             idx_pblock(path->p_idx));
439                 } else if (path->p_ext) {
440                         ext_debug("  %d:%d:%llu ",
441                                   le32_to_cpu(path->p_ext->ee_block),
442                                   ext4_ext_get_actual_len(path->p_ext),
443                                   ext_pblock(path->p_ext));
444                 } else
445                         ext_debug("  []");
446         }
447         ext_debug("\n");
448 }
449
450 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
451 {
452         int depth = ext_depth(inode);
453         struct ext4_extent_header *eh;
454         struct ext4_extent *ex;
455         int i;
456
457         if (!path)
458                 return;
459
460         eh = path[depth].p_hdr;
461         ex = EXT_FIRST_EXTENT(eh);
462
463         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
464                 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
465                           ext4_ext_get_actual_len(ex), ext_pblock(ex));
466         }
467         ext_debug("\n");
468 }
469 #else
470 #define ext4_ext_show_path(inode, path)
471 #define ext4_ext_show_leaf(inode, path)
472 #endif
473
474 void ext4_ext_drop_refs(struct ext4_ext_path *path)
475 {
476         int depth = path->p_depth;
477         int i;
478
479         for (i = 0; i <= depth; i++, path++)
480                 if (path->p_bh) {
481                         brelse(path->p_bh);
482                         path->p_bh = NULL;
483                 }
484 }
485
486 /*
487  * ext4_ext_binsearch_idx:
488  * binary search for the closest index of the given block
489  * the header must be checked before calling this
490  */
491 static void
492 ext4_ext_binsearch_idx(struct inode *inode,
493                         struct ext4_ext_path *path, ext4_lblk_t block)
494 {
495         struct ext4_extent_header *eh = path->p_hdr;
496         struct ext4_extent_idx *r, *l, *m;
497
498
499         ext_debug("binsearch for %u(idx):  ", block);
500
501         l = EXT_FIRST_INDEX(eh) + 1;
502         r = EXT_LAST_INDEX(eh);
503         while (l <= r) {
504                 m = l + (r - l) / 2;
505                 if (block < le32_to_cpu(m->ei_block))
506                         r = m - 1;
507                 else
508                         l = m + 1;
509                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
510                                 m, le32_to_cpu(m->ei_block),
511                                 r, le32_to_cpu(r->ei_block));
512         }
513
514         path->p_idx = l - 1;
515         ext_debug("  -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
516                   idx_pblock(path->p_idx));
517
518 #ifdef CHECK_BINSEARCH
519         {
520                 struct ext4_extent_idx *chix, *ix;
521                 int k;
522
523                 chix = ix = EXT_FIRST_INDEX(eh);
524                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
525                   if (k != 0 &&
526                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
527                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
528                                        "first=0x%p\n", k,
529                                        ix, EXT_FIRST_INDEX(eh));
530                                 printk(KERN_DEBUG "%u <= %u\n",
531                                        le32_to_cpu(ix->ei_block),
532                                        le32_to_cpu(ix[-1].ei_block));
533                         }
534                         BUG_ON(k && le32_to_cpu(ix->ei_block)
535                                            <= le32_to_cpu(ix[-1].ei_block));
536                         if (block < le32_to_cpu(ix->ei_block))
537                                 break;
538                         chix = ix;
539                 }
540                 BUG_ON(chix != path->p_idx);
541         }
542 #endif
543
544 }
545
546 /*
547  * ext4_ext_binsearch:
548  * binary search for closest extent of the given block
549  * the header must be checked before calling this
550  */
551 static void
552 ext4_ext_binsearch(struct inode *inode,
553                 struct ext4_ext_path *path, ext4_lblk_t block)
554 {
555         struct ext4_extent_header *eh = path->p_hdr;
556         struct ext4_extent *r, *l, *m;
557
558         if (eh->eh_entries == 0) {
559                 /*
560                  * this leaf is empty:
561                  * we get such a leaf in split/add case
562                  */
563                 return;
564         }
565
566         ext_debug("binsearch for %u:  ", block);
567
568         l = EXT_FIRST_EXTENT(eh) + 1;
569         r = EXT_LAST_EXTENT(eh);
570
571         while (l <= r) {
572                 m = l + (r - l) / 2;
573                 if (block < le32_to_cpu(m->ee_block))
574                         r = m - 1;
575                 else
576                         l = m + 1;
577                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
578                                 m, le32_to_cpu(m->ee_block),
579                                 r, le32_to_cpu(r->ee_block));
580         }
581
582         path->p_ext = l - 1;
583         ext_debug("  -> %d:%llu:%d ",
584                         le32_to_cpu(path->p_ext->ee_block),
585                         ext_pblock(path->p_ext),
586                         ext4_ext_get_actual_len(path->p_ext));
587
588 #ifdef CHECK_BINSEARCH
589         {
590                 struct ext4_extent *chex, *ex;
591                 int k;
592
593                 chex = ex = EXT_FIRST_EXTENT(eh);
594                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
595                         BUG_ON(k && le32_to_cpu(ex->ee_block)
596                                           <= le32_to_cpu(ex[-1].ee_block));
597                         if (block < le32_to_cpu(ex->ee_block))
598                                 break;
599                         chex = ex;
600                 }
601                 BUG_ON(chex != path->p_ext);
602         }
603 #endif
604
605 }
606
607 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
608 {
609         struct ext4_extent_header *eh;
610
611         eh = ext_inode_hdr(inode);
612         eh->eh_depth = 0;
613         eh->eh_entries = 0;
614         eh->eh_magic = EXT4_EXT_MAGIC;
615         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
616         ext4_mark_inode_dirty(handle, inode);
617         ext4_ext_invalidate_cache(inode);
618         return 0;
619 }
620
621 struct ext4_ext_path *
622 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
623                                         struct ext4_ext_path *path)
624 {
625         struct ext4_extent_header *eh;
626         struct buffer_head *bh;
627         short int depth, i, ppos = 0, alloc = 0;
628
629         eh = ext_inode_hdr(inode);
630         depth = ext_depth(inode);
631
632         /* account possible depth increase */
633         if (!path) {
634                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
635                                 GFP_NOFS);
636                 if (!path)
637                         return ERR_PTR(-ENOMEM);
638                 alloc = 1;
639         }
640         path[0].p_hdr = eh;
641         path[0].p_bh = NULL;
642
643         i = depth;
644         /* walk through the tree */
645         while (i) {
646                 int need_to_validate = 0;
647
648                 ext_debug("depth %d: num %d, max %d\n",
649                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
650
651                 ext4_ext_binsearch_idx(inode, path + ppos, block);
652                 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
653                 path[ppos].p_depth = i;
654                 path[ppos].p_ext = NULL;
655
656                 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
657                 if (unlikely(!bh))
658                         goto err;
659                 if (!bh_uptodate_or_lock(bh)) {
660                         if (bh_submit_read(bh) < 0) {
661                                 put_bh(bh);
662                                 goto err;
663                         }
664                         /* validate the extent entries */
665                         need_to_validate = 1;
666                 }
667                 eh = ext_block_hdr(bh);
668                 ppos++;
669                 BUG_ON(ppos > depth);
670                 path[ppos].p_bh = bh;
671                 path[ppos].p_hdr = eh;
672                 i--;
673
674                 if (need_to_validate && ext4_ext_check(inode, eh, i))
675                         goto err;
676         }
677
678         path[ppos].p_depth = i;
679         path[ppos].p_ext = NULL;
680         path[ppos].p_idx = NULL;
681
682         /* find extent */
683         ext4_ext_binsearch(inode, path + ppos, block);
684         /* if not an empty leaf */
685         if (path[ppos].p_ext)
686                 path[ppos].p_block = ext_pblock(path[ppos].p_ext);
687
688         ext4_ext_show_path(inode, path);
689
690         return path;
691
692 err:
693         ext4_ext_drop_refs(path);
694         if (alloc)
695                 kfree(path);
696         return ERR_PTR(-EIO);
697 }
698
699 /*
700  * ext4_ext_insert_index:
701  * insert new index [@logical;@ptr] into the block at @curp;
702  * check where to insert: before @curp or after @curp
703  */
704 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
705                                 struct ext4_ext_path *curp,
706                                 int logical, ext4_fsblk_t ptr)
707 {
708         struct ext4_extent_idx *ix;
709         int len, err;
710
711         err = ext4_ext_get_access(handle, inode, curp);
712         if (err)
713                 return err;
714
715         BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
716         len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
717         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
718                 /* insert after */
719                 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
720                         len = (len - 1) * sizeof(struct ext4_extent_idx);
721                         len = len < 0 ? 0 : len;
722                         ext_debug("insert new index %d after: %llu. "
723                                         "move %d from 0x%p to 0x%p\n",
724                                         logical, ptr, len,
725                                         (curp->p_idx + 1), (curp->p_idx + 2));
726                         memmove(curp->p_idx + 2, curp->p_idx + 1, len);
727                 }
728                 ix = curp->p_idx + 1;
729         } else {
730                 /* insert before */
731                 len = len * sizeof(struct ext4_extent_idx);
732                 len = len < 0 ? 0 : len;
733                 ext_debug("insert new index %d before: %llu. "
734                                 "move %d from 0x%p to 0x%p\n",
735                                 logical, ptr, len,
736                                 curp->p_idx, (curp->p_idx + 1));
737                 memmove(curp->p_idx + 1, curp->p_idx, len);
738                 ix = curp->p_idx;
739         }
740
741         ix->ei_block = cpu_to_le32(logical);
742         ext4_idx_store_pblock(ix, ptr);
743         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
744
745         BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
746                              > le16_to_cpu(curp->p_hdr->eh_max));
747         BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
748
749         err = ext4_ext_dirty(handle, inode, curp);
750         ext4_std_error(inode->i_sb, err);
751
752         return err;
753 }
754
755 /*
756  * ext4_ext_split:
757  * inserts new subtree into the path, using free index entry
758  * at depth @at:
759  * - allocates all needed blocks (new leaf and all intermediate index blocks)
760  * - makes decision where to split
761  * - moves remaining extents and index entries (right to the split point)
762  *   into the newly allocated blocks
763  * - initializes subtree
764  */
765 static int ext4_ext_split(handle_t *handle, struct inode *inode,
766                                 struct ext4_ext_path *path,
767                                 struct ext4_extent *newext, int at)
768 {
769         struct buffer_head *bh = NULL;
770         int depth = ext_depth(inode);
771         struct ext4_extent_header *neh;
772         struct ext4_extent_idx *fidx;
773         struct ext4_extent *ex;
774         int i = at, k, m, a;
775         ext4_fsblk_t newblock, oldblock;
776         __le32 border;
777         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
778         int err = 0;
779
780         /* make decision: where to split? */
781         /* FIXME: now decision is simplest: at current extent */
782
783         /* if current leaf will be split, then we should use
784          * border from split point */
785         BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
786         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
787                 border = path[depth].p_ext[1].ee_block;
788                 ext_debug("leaf will be split."
789                                 " next leaf starts at %d\n",
790                                   le32_to_cpu(border));
791         } else {
792                 border = newext->ee_block;
793                 ext_debug("leaf will be added."
794                                 " next leaf starts at %d\n",
795                                 le32_to_cpu(border));
796         }
797
798         /*
799          * If error occurs, then we break processing
800          * and mark filesystem read-only. index won't
801          * be inserted and tree will be in consistent
802          * state. Next mount will repair buffers too.
803          */
804
805         /*
806          * Get array to track all allocated blocks.
807          * We need this to handle errors and free blocks
808          * upon them.
809          */
810         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
811         if (!ablocks)
812                 return -ENOMEM;
813
814         /* allocate all needed blocks */
815         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
816         for (a = 0; a < depth - at; a++) {
817                 newblock = ext4_ext_new_meta_block(handle, inode, path,
818                                                    newext, &err);
819                 if (newblock == 0)
820                         goto cleanup;
821                 ablocks[a] = newblock;
822         }
823
824         /* initialize new leaf */
825         newblock = ablocks[--a];
826         BUG_ON(newblock == 0);
827         bh = sb_getblk(inode->i_sb, newblock);
828         if (!bh) {
829                 err = -EIO;
830                 goto cleanup;
831         }
832         lock_buffer(bh);
833
834         err = ext4_journal_get_create_access(handle, bh);
835         if (err)
836                 goto cleanup;
837
838         neh = ext_block_hdr(bh);
839         neh->eh_entries = 0;
840         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
841         neh->eh_magic = EXT4_EXT_MAGIC;
842         neh->eh_depth = 0;
843         ex = EXT_FIRST_EXTENT(neh);
844
845         /* move remainder of path[depth] to the new leaf */
846         BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
847         /* start copy from next extent */
848         /* TODO: we could do it by single memmove */
849         m = 0;
850         path[depth].p_ext++;
851         while (path[depth].p_ext <=
852                         EXT_MAX_EXTENT(path[depth].p_hdr)) {
853                 ext_debug("move %d:%llu:%d in new leaf %llu\n",
854                                 le32_to_cpu(path[depth].p_ext->ee_block),
855                                 ext_pblock(path[depth].p_ext),
856                                 ext4_ext_get_actual_len(path[depth].p_ext),
857                                 newblock);
858                 /*memmove(ex++, path[depth].p_ext++,
859                                 sizeof(struct ext4_extent));
860                 neh->eh_entries++;*/
861                 path[depth].p_ext++;
862                 m++;
863         }
864         if (m) {
865                 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
866                 le16_add_cpu(&neh->eh_entries, m);
867         }
868
869         set_buffer_uptodate(bh);
870         unlock_buffer(bh);
871
872         err = ext4_handle_dirty_metadata(handle, inode, bh);
873         if (err)
874                 goto cleanup;
875         brelse(bh);
876         bh = NULL;
877
878         /* correct old leaf */
879         if (m) {
880                 err = ext4_ext_get_access(handle, inode, path + depth);
881                 if (err)
882                         goto cleanup;
883                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
884                 err = ext4_ext_dirty(handle, inode, path + depth);
885                 if (err)
886                         goto cleanup;
887
888         }
889
890         /* create intermediate indexes */
891         k = depth - at - 1;
892         BUG_ON(k < 0);
893         if (k)
894                 ext_debug("create %d intermediate indices\n", k);
895         /* insert new index into current index block */
896         /* current depth stored in i var */
897         i = depth - 1;
898         while (k--) {
899                 oldblock = newblock;
900                 newblock = ablocks[--a];
901                 bh = sb_getblk(inode->i_sb, newblock);
902                 if (!bh) {
903                         err = -EIO;
904                         goto cleanup;
905                 }
906                 lock_buffer(bh);
907
908                 err = ext4_journal_get_create_access(handle, bh);
909                 if (err)
910                         goto cleanup;
911
912                 neh = ext_block_hdr(bh);
913                 neh->eh_entries = cpu_to_le16(1);
914                 neh->eh_magic = EXT4_EXT_MAGIC;
915                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
916                 neh->eh_depth = cpu_to_le16(depth - i);
917                 fidx = EXT_FIRST_INDEX(neh);
918                 fidx->ei_block = border;
919                 ext4_idx_store_pblock(fidx, oldblock);
920
921                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
922                                 i, newblock, le32_to_cpu(border), oldblock);
923                 /* copy indexes */
924                 m = 0;
925                 path[i].p_idx++;
926
927                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
928                                 EXT_MAX_INDEX(path[i].p_hdr));
929                 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
930                                 EXT_LAST_INDEX(path[i].p_hdr));
931                 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
932                         ext_debug("%d: move %d:%llu in new index %llu\n", i,
933                                         le32_to_cpu(path[i].p_idx->ei_block),
934                                         idx_pblock(path[i].p_idx),
935                                         newblock);
936                         /*memmove(++fidx, path[i].p_idx++,
937                                         sizeof(struct ext4_extent_idx));
938                         neh->eh_entries++;
939                         BUG_ON(neh->eh_entries > neh->eh_max);*/
940                         path[i].p_idx++;
941                         m++;
942                 }
943                 if (m) {
944                         memmove(++fidx, path[i].p_idx - m,
945                                 sizeof(struct ext4_extent_idx) * m);
946                         le16_add_cpu(&neh->eh_entries, m);
947                 }
948                 set_buffer_uptodate(bh);
949                 unlock_buffer(bh);
950
951                 err = ext4_handle_dirty_metadata(handle, inode, bh);
952                 if (err)
953                         goto cleanup;
954                 brelse(bh);
955                 bh = NULL;
956
957                 /* correct old index */
958                 if (m) {
959                         err = ext4_ext_get_access(handle, inode, path + i);
960                         if (err)
961                                 goto cleanup;
962                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
963                         err = ext4_ext_dirty(handle, inode, path + i);
964                         if (err)
965                                 goto cleanup;
966                 }
967
968                 i--;
969         }
970
971         /* insert new index */
972         err = ext4_ext_insert_index(handle, inode, path + at,
973                                     le32_to_cpu(border), newblock);
974
975 cleanup:
976         if (bh) {
977                 if (buffer_locked(bh))
978                         unlock_buffer(bh);
979                 brelse(bh);
980         }
981
982         if (err) {
983                 /* free all allocated blocks in error case */
984                 for (i = 0; i < depth; i++) {
985                         if (!ablocks[i])
986                                 continue;
987                         ext4_free_blocks(handle, inode, ablocks[i], 1, 1);
988                 }
989         }
990         kfree(ablocks);
991
992         return err;
993 }
994
995 /*
996  * ext4_ext_grow_indepth:
997  * implements tree growing procedure:
998  * - allocates new block
999  * - moves top-level data (index block or leaf) into the new block
1000  * - initializes new top-level, creating index that points to the
1001  *   just created block
1002  */
1003 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1004                                         struct ext4_ext_path *path,
1005                                         struct ext4_extent *newext)
1006 {
1007         struct ext4_ext_path *curp = path;
1008         struct ext4_extent_header *neh;
1009         struct ext4_extent_idx *fidx;
1010         struct buffer_head *bh;
1011         ext4_fsblk_t newblock;
1012         int err = 0;
1013
1014         newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
1015         if (newblock == 0)
1016                 return err;
1017
1018         bh = sb_getblk(inode->i_sb, newblock);
1019         if (!bh) {
1020                 err = -EIO;
1021                 ext4_std_error(inode->i_sb, err);
1022                 return err;
1023         }
1024         lock_buffer(bh);
1025
1026         err = ext4_journal_get_create_access(handle, bh);
1027         if (err) {
1028                 unlock_buffer(bh);
1029                 goto out;
1030         }
1031
1032         /* move top-level index/leaf into new block */
1033         memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
1034
1035         /* set size of new block */
1036         neh = ext_block_hdr(bh);
1037         /* old root could have indexes or leaves
1038          * so calculate e_max right way */
1039         if (ext_depth(inode))
1040           neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
1041         else
1042           neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
1043         neh->eh_magic = EXT4_EXT_MAGIC;
1044         set_buffer_uptodate(bh);
1045         unlock_buffer(bh);
1046
1047         err = ext4_handle_dirty_metadata(handle, inode, bh);
1048         if (err)
1049                 goto out;
1050
1051         /* create index in new top-level index: num,max,pointer */
1052         err = ext4_ext_get_access(handle, inode, curp);
1053         if (err)
1054                 goto out;
1055
1056         curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
1057         curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
1058         curp->p_hdr->eh_entries = cpu_to_le16(1);
1059         curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
1060
1061         if (path[0].p_hdr->eh_depth)
1062                 curp->p_idx->ei_block =
1063                         EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
1064         else
1065                 curp->p_idx->ei_block =
1066                         EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
1067         ext4_idx_store_pblock(curp->p_idx, newblock);
1068
1069         neh = ext_inode_hdr(inode);
1070         fidx = EXT_FIRST_INDEX(neh);
1071         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1072                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1073                   le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
1074
1075         neh->eh_depth = cpu_to_le16(path->p_depth + 1);
1076         err = ext4_ext_dirty(handle, inode, curp);
1077 out:
1078         brelse(bh);
1079
1080         return err;
1081 }
1082
1083 /*
1084  * ext4_ext_create_new_leaf:
1085  * finds empty index and adds new leaf.
1086  * if no free index is found, then it requests in-depth growing.
1087  */
1088 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1089                                         struct ext4_ext_path *path,
1090                                         struct ext4_extent *newext)
1091 {
1092         struct ext4_ext_path *curp;
1093         int depth, i, err = 0;
1094
1095 repeat:
1096         i = depth = ext_depth(inode);
1097
1098         /* walk up to the tree and look for free index entry */
1099         curp = path + depth;
1100         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1101                 i--;
1102                 curp--;
1103         }
1104
1105         /* we use already allocated block for index block,
1106          * so subsequent data blocks should be contiguous */
1107         if (EXT_HAS_FREE_INDEX(curp)) {
1108                 /* if we found index with free entry, then use that
1109                  * entry: create all needed subtree and add new leaf */
1110                 err = ext4_ext_split(handle, inode, path, newext, i);
1111                 if (err)
1112                         goto out;
1113
1114                 /* refill path */
1115                 ext4_ext_drop_refs(path);
1116                 path = ext4_ext_find_extent(inode,
1117                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1118                                     path);
1119                 if (IS_ERR(path))
1120                         err = PTR_ERR(path);
1121         } else {
1122                 /* tree is full, time to grow in depth */
1123                 err = ext4_ext_grow_indepth(handle, inode, path, newext);
1124                 if (err)
1125                         goto out;
1126
1127                 /* refill path */
1128                 ext4_ext_drop_refs(path);
1129                 path = ext4_ext_find_extent(inode,
1130                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1131                                     path);
1132                 if (IS_ERR(path)) {
1133                         err = PTR_ERR(path);
1134                         goto out;
1135                 }
1136
1137                 /*
1138                  * only first (depth 0 -> 1) produces free space;
1139                  * in all other cases we have to split the grown tree
1140                  */
1141                 depth = ext_depth(inode);
1142                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1143                         /* now we need to split */
1144                         goto repeat;
1145                 }
1146         }
1147
1148 out:
1149         return err;
1150 }
1151
1152 /*
1153  * search the closest allocated block to the left for *logical
1154  * and returns it at @logical + it's physical address at @phys
1155  * if *logical is the smallest allocated block, the function
1156  * returns 0 at @phys
1157  * return value contains 0 (success) or error code
1158  */
1159 int
1160 ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path,
1161                         ext4_lblk_t *logical, ext4_fsblk_t *phys)
1162 {
1163         struct ext4_extent_idx *ix;
1164         struct ext4_extent *ex;
1165         int depth, ee_len;
1166
1167         BUG_ON(path == NULL);
1168         depth = path->p_depth;
1169         *phys = 0;
1170
1171         if (depth == 0 && path->p_ext == NULL)
1172                 return 0;
1173
1174         /* usually extent in the path covers blocks smaller
1175          * then *logical, but it can be that extent is the
1176          * first one in the file */
1177
1178         ex = path[depth].p_ext;
1179         ee_len = ext4_ext_get_actual_len(ex);
1180         if (*logical < le32_to_cpu(ex->ee_block)) {
1181                 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex);
1182                 while (--depth >= 0) {
1183                         ix = path[depth].p_idx;
1184                         BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr));
1185                 }
1186                 return 0;
1187         }
1188
1189         BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len));
1190
1191         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1192         *phys = ext_pblock(ex) + ee_len - 1;
1193         return 0;
1194 }
1195
1196 /*
1197  * search the closest allocated block to the right for *logical
1198  * and returns it at @logical + it's physical address at @phys
1199  * if *logical is the smallest allocated block, the function
1200  * returns 0 at @phys
1201  * return value contains 0 (success) or error code
1202  */
1203 int
1204 ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path,
1205                         ext4_lblk_t *logical, ext4_fsblk_t *phys)
1206 {
1207         struct buffer_head *bh = NULL;
1208         struct ext4_extent_header *eh;
1209         struct ext4_extent_idx *ix;
1210         struct ext4_extent *ex;
1211         ext4_fsblk_t block;
1212         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1213         int ee_len;
1214
1215         BUG_ON(path == NULL);
1216         depth = path->p_depth;
1217         *phys = 0;
1218
1219         if (depth == 0 && path->p_ext == NULL)
1220                 return 0;
1221
1222         /* usually extent in the path covers blocks smaller
1223          * then *logical, but it can be that extent is the
1224          * first one in the file */
1225
1226         ex = path[depth].p_ext;
1227         ee_len = ext4_ext_get_actual_len(ex);
1228         if (*logical < le32_to_cpu(ex->ee_block)) {
1229                 BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex);
1230                 while (--depth >= 0) {
1231                         ix = path[depth].p_idx;
1232                         BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr));
1233                 }
1234                 *logical = le32_to_cpu(ex->ee_block);
1235                 *phys = ext_pblock(ex);
1236                 return 0;
1237         }
1238
1239         BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len));
1240
1241         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1242                 /* next allocated block in this leaf */
1243                 ex++;
1244                 *logical = le32_to_cpu(ex->ee_block);
1245                 *phys = ext_pblock(ex);
1246                 return 0;
1247         }
1248
1249         /* go up and search for index to the right */
1250         while (--depth >= 0) {
1251                 ix = path[depth].p_idx;
1252                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1253                         goto got_index;
1254         }
1255
1256         /* we've gone up to the root and found no index to the right */
1257         return 0;
1258
1259 got_index:
1260         /* we've found index to the right, let's
1261          * follow it and find the closest allocated
1262          * block to the right */
1263         ix++;
1264         block = idx_pblock(ix);
1265         while (++depth < path->p_depth) {
1266                 bh = sb_bread(inode->i_sb, block);
1267                 if (bh == NULL)
1268                         return -EIO;
1269                 eh = ext_block_hdr(bh);
1270                 /* subtract from p_depth to get proper eh_depth */
1271                 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1272                         put_bh(bh);
1273                         return -EIO;
1274                 }
1275                 ix = EXT_FIRST_INDEX(eh);
1276                 block = idx_pblock(ix);
1277                 put_bh(bh);
1278         }
1279
1280         bh = sb_bread(inode->i_sb, block);
1281         if (bh == NULL)
1282                 return -EIO;
1283         eh = ext_block_hdr(bh);
1284         if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1285                 put_bh(bh);
1286                 return -EIO;
1287         }
1288         ex = EXT_FIRST_EXTENT(eh);
1289         *logical = le32_to_cpu(ex->ee_block);
1290         *phys = ext_pblock(ex);
1291         put_bh(bh);
1292         return 0;
1293 }
1294
1295 /*
1296  * ext4_ext_next_allocated_block:
1297  * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
1298  * NOTE: it considers block number from index entry as
1299  * allocated block. Thus, index entries have to be consistent
1300  * with leaves.
1301  */
1302 static ext4_lblk_t
1303 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1304 {
1305         int depth;
1306
1307         BUG_ON(path == NULL);
1308         depth = path->p_depth;
1309
1310         if (depth == 0 && path->p_ext == NULL)
1311                 return EXT_MAX_BLOCK;
1312
1313         while (depth >= 0) {
1314                 if (depth == path->p_depth) {
1315                         /* leaf */
1316                         if (path[depth].p_ext !=
1317                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1318                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1319                 } else {
1320                         /* index */
1321                         if (path[depth].p_idx !=
1322                                         EXT_LAST_INDEX(path[depth].p_hdr))
1323                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1324                 }
1325                 depth--;
1326         }
1327
1328         return EXT_MAX_BLOCK;
1329 }
1330
1331 /*
1332  * ext4_ext_next_leaf_block:
1333  * returns first allocated block from next leaf or EXT_MAX_BLOCK
1334  */
1335 static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
1336                                         struct ext4_ext_path *path)
1337 {
1338         int depth;
1339
1340         BUG_ON(path == NULL);
1341         depth = path->p_depth;
1342
1343         /* zero-tree has no leaf blocks at all */
1344         if (depth == 0)
1345                 return EXT_MAX_BLOCK;
1346
1347         /* go to index block */
1348         depth--;
1349
1350         while (depth >= 0) {
1351                 if (path[depth].p_idx !=
1352                                 EXT_LAST_INDEX(path[depth].p_hdr))
1353                         return (ext4_lblk_t)
1354                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1355                 depth--;
1356         }
1357
1358         return EXT_MAX_BLOCK;
1359 }
1360
1361 /*
1362  * ext4_ext_correct_indexes:
1363  * if leaf gets modified and modified extent is first in the leaf,
1364  * then we have to correct all indexes above.
1365  * TODO: do we need to correct tree in all cases?
1366  */
1367 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1368                                 struct ext4_ext_path *path)
1369 {
1370         struct ext4_extent_header *eh;
1371         int depth = ext_depth(inode);
1372         struct ext4_extent *ex;
1373         __le32 border;
1374         int k, err = 0;
1375
1376         eh = path[depth].p_hdr;
1377         ex = path[depth].p_ext;
1378         BUG_ON(ex == NULL);
1379         BUG_ON(eh == NULL);
1380
1381         if (depth == 0) {
1382                 /* there is no tree at all */
1383                 return 0;
1384         }
1385
1386         if (ex != EXT_FIRST_EXTENT(eh)) {
1387                 /* we correct tree if first leaf got modified only */
1388                 return 0;
1389         }
1390
1391         /*
1392          * TODO: we need correction if border is smaller than current one
1393          */
1394         k = depth - 1;
1395         border = path[depth].p_ext->ee_block;
1396         err = ext4_ext_get_access(handle, inode, path + k);
1397         if (err)
1398                 return err;
1399         path[k].p_idx->ei_block = border;
1400         err = ext4_ext_dirty(handle, inode, path + k);
1401         if (err)
1402                 return err;
1403
1404         while (k--) {
1405                 /* change all left-side indexes */
1406                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1407                         break;
1408                 err = ext4_ext_get_access(handle, inode, path + k);
1409                 if (err)
1410                         break;
1411                 path[k].p_idx->ei_block = border;
1412                 err = ext4_ext_dirty(handle, inode, path + k);
1413                 if (err)
1414                         break;
1415         }
1416
1417         return err;
1418 }
1419
1420 int
1421 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1422                                 struct ext4_extent *ex2)
1423 {
1424         unsigned short ext1_ee_len, ext2_ee_len, max_len;
1425
1426         /*
1427          * Make sure that either both extents are uninitialized, or
1428          * both are _not_.
1429          */
1430         if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1431                 return 0;
1432
1433         if (ext4_ext_is_uninitialized(ex1))
1434                 max_len = EXT_UNINIT_MAX_LEN;
1435         else
1436                 max_len = EXT_INIT_MAX_LEN;
1437
1438         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1439         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1440
1441         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1442                         le32_to_cpu(ex2->ee_block))
1443                 return 0;
1444
1445         /*
1446          * To allow future support for preallocated extents to be added
1447          * as an RO_COMPAT feature, refuse to merge to extents if
1448          * this can result in the top bit of ee_len being set.
1449          */
1450         if (ext1_ee_len + ext2_ee_len > max_len)
1451                 return 0;
1452 #ifdef AGGRESSIVE_TEST
1453         if (ext1_ee_len >= 4)
1454                 return 0;
1455 #endif
1456
1457         if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
1458                 return 1;
1459         return 0;
1460 }
1461
1462 /*
1463  * This function tries to merge the "ex" extent to the next extent in the tree.
1464  * It always tries to merge towards right. If you want to merge towards
1465  * left, pass "ex - 1" as argument instead of "ex".
1466  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1467  * 1 if they got merged.
1468  */
1469 int ext4_ext_try_to_merge(struct inode *inode,
1470                           struct ext4_ext_path *path,
1471                           struct ext4_extent *ex)
1472 {
1473         struct ext4_extent_header *eh;
1474         unsigned int depth, len;
1475         int merge_done = 0;
1476         int uninitialized = 0;
1477
1478         depth = ext_depth(inode);
1479         BUG_ON(path[depth].p_hdr == NULL);
1480         eh = path[depth].p_hdr;
1481
1482         while (ex < EXT_LAST_EXTENT(eh)) {
1483                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1484                         break;
1485                 /* merge with next extent! */
1486                 if (ext4_ext_is_uninitialized(ex))
1487                         uninitialized = 1;
1488                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1489                                 + ext4_ext_get_actual_len(ex + 1));
1490                 if (uninitialized)
1491                         ext4_ext_mark_uninitialized(ex);
1492
1493                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1494                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1495                                 * sizeof(struct ext4_extent);
1496                         memmove(ex + 1, ex + 2, len);
1497                 }
1498                 le16_add_cpu(&eh->eh_entries, -1);
1499                 merge_done = 1;
1500                 WARN_ON(eh->eh_entries == 0);
1501                 if (!eh->eh_entries)
1502                         ext4_error(inode->i_sb, "ext4_ext_try_to_merge",
1503                            "inode#%lu, eh->eh_entries = 0!", inode->i_ino);
1504         }
1505
1506         return merge_done;
1507 }
1508
1509 /*
1510  * check if a portion of the "newext" extent overlaps with an
1511  * existing extent.
1512  *
1513  * If there is an overlap discovered, it updates the length of the newext
1514  * such that there will be no overlap, and then returns 1.
1515  * If there is no overlap found, it returns 0.
1516  */
1517 unsigned int ext4_ext_check_overlap(struct inode *inode,
1518                                     struct ext4_extent *newext,
1519                                     struct ext4_ext_path *path)
1520 {
1521         ext4_lblk_t b1, b2;
1522         unsigned int depth, len1;
1523         unsigned int ret = 0;
1524
1525         b1 = le32_to_cpu(newext->ee_block);
1526         len1 = ext4_ext_get_actual_len(newext);
1527         depth = ext_depth(inode);
1528         if (!path[depth].p_ext)
1529                 goto out;
1530         b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1531
1532         /*
1533          * get the next allocated block if the extent in the path
1534          * is before the requested block(s)
1535          */
1536         if (b2 < b1) {
1537                 b2 = ext4_ext_next_allocated_block(path);
1538                 if (b2 == EXT_MAX_BLOCK)
1539                         goto out;
1540         }
1541
1542         /* check for wrap through zero on extent logical start block*/
1543         if (b1 + len1 < b1) {
1544                 len1 = EXT_MAX_BLOCK - b1;
1545                 newext->ee_len = cpu_to_le16(len1);
1546                 ret = 1;
1547         }
1548
1549         /* check for overlap */
1550         if (b1 + len1 > b2) {
1551                 newext->ee_len = cpu_to_le16(b2 - b1);
1552                 ret = 1;
1553         }
1554 out:
1555         return ret;
1556 }
1557
1558 /*
1559  * ext4_ext_insert_extent:
1560  * tries to merge requsted extent into the existing extent or
1561  * inserts requested extent as new one into the tree,
1562  * creating new leaf in the no-space case.
1563  */
1564 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1565                                 struct ext4_ext_path *path,
1566                                 struct ext4_extent *newext)
1567 {
1568         struct ext4_extent_header *eh;
1569         struct ext4_extent *ex, *fex;
1570         struct ext4_extent *nearex; /* nearest extent */
1571         struct ext4_ext_path *npath = NULL;
1572         int depth, len, err;
1573         ext4_lblk_t next;
1574         unsigned uninitialized = 0;
1575
1576         BUG_ON(ext4_ext_get_actual_len(newext) == 0);
1577         depth = ext_depth(inode);
1578         ex = path[depth].p_ext;
1579         BUG_ON(path[depth].p_hdr == NULL);
1580
1581         /* try to insert block into found extent and return */
1582         if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
1583                 ext_debug("append %d block to %d:%d (from %llu)\n",
1584                                 ext4_ext_get_actual_len(newext),
1585                                 le32_to_cpu(ex->ee_block),
1586                                 ext4_ext_get_actual_len(ex), ext_pblock(ex));
1587                 err = ext4_ext_get_access(handle, inode, path + depth);
1588                 if (err)
1589                         return err;
1590
1591                 /*
1592                  * ext4_can_extents_be_merged should have checked that either
1593                  * both extents are uninitialized, or both aren't. Thus we
1594                  * need to check only one of them here.
1595                  */
1596                 if (ext4_ext_is_uninitialized(ex))
1597                         uninitialized = 1;
1598                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1599                                         + ext4_ext_get_actual_len(newext));
1600                 if (uninitialized)
1601                         ext4_ext_mark_uninitialized(ex);
1602                 eh = path[depth].p_hdr;
1603                 nearex = ex;
1604                 goto merge;
1605         }
1606
1607 repeat:
1608         depth = ext_depth(inode);
1609         eh = path[depth].p_hdr;
1610         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1611                 goto has_space;
1612
1613         /* probably next leaf has space for us? */
1614         fex = EXT_LAST_EXTENT(eh);
1615         next = ext4_ext_next_leaf_block(inode, path);
1616         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1617             && next != EXT_MAX_BLOCK) {
1618                 ext_debug("next leaf block - %d\n", next);
1619                 BUG_ON(npath != NULL);
1620                 npath = ext4_ext_find_extent(inode, next, NULL);
1621                 if (IS_ERR(npath))
1622                         return PTR_ERR(npath);
1623                 BUG_ON(npath->p_depth != path->p_depth);
1624                 eh = npath[depth].p_hdr;
1625                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1626                         ext_debug("next leaf isnt full(%d)\n",
1627                                   le16_to_cpu(eh->eh_entries));
1628                         path = npath;
1629                         goto repeat;
1630                 }
1631                 ext_debug("next leaf has no free space(%d,%d)\n",
1632                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1633         }
1634
1635         /*
1636          * There is no free space in the found leaf.
1637          * We're gonna add a new leaf in the tree.
1638          */
1639         err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1640         if (err)
1641                 goto cleanup;
1642         depth = ext_depth(inode);
1643         eh = path[depth].p_hdr;
1644
1645 has_space:
1646         nearex = path[depth].p_ext;
1647
1648         err = ext4_ext_get_access(handle, inode, path + depth);
1649         if (err)
1650                 goto cleanup;
1651
1652         if (!nearex) {
1653                 /* there is no extent in this leaf, create first one */
1654                 ext_debug("first extent in the leaf: %d:%llu:%d\n",
1655                                 le32_to_cpu(newext->ee_block),
1656                                 ext_pblock(newext),
1657                                 ext4_ext_get_actual_len(newext));
1658                 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1659         } else if (le32_to_cpu(newext->ee_block)
1660                            > le32_to_cpu(nearex->ee_block)) {
1661 /*              BUG_ON(newext->ee_block == nearex->ee_block); */
1662                 if (nearex != EXT_LAST_EXTENT(eh)) {
1663                         len = EXT_MAX_EXTENT(eh) - nearex;
1664                         len = (len - 1) * sizeof(struct ext4_extent);
1665                         len = len < 0 ? 0 : len;
1666                         ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
1667                                         "move %d from 0x%p to 0x%p\n",
1668                                         le32_to_cpu(newext->ee_block),
1669                                         ext_pblock(newext),
1670                                         ext4_ext_get_actual_len(newext),
1671                                         nearex, len, nearex + 1, nearex + 2);
1672                         memmove(nearex + 2, nearex + 1, len);
1673                 }
1674                 path[depth].p_ext = nearex + 1;
1675         } else {
1676                 BUG_ON(newext->ee_block == nearex->ee_block);
1677                 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1678                 len = len < 0 ? 0 : len;
1679                 ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
1680                                 "move %d from 0x%p to 0x%p\n",
1681                                 le32_to_cpu(newext->ee_block),
1682                                 ext_pblock(newext),
1683                                 ext4_ext_get_actual_len(newext),
1684                                 nearex, len, nearex + 1, nearex + 2);
1685                 memmove(nearex + 1, nearex, len);
1686                 path[depth].p_ext = nearex;
1687         }
1688
1689         le16_add_cpu(&eh->eh_entries, 1);
1690         nearex = path[depth].p_ext;
1691         nearex->ee_block = newext->ee_block;
1692         ext4_ext_store_pblock(nearex, ext_pblock(newext));
1693         nearex->ee_len = newext->ee_len;
1694
1695 merge:
1696         /* try to merge extents to the right */
1697         ext4_ext_try_to_merge(inode, path, nearex);
1698
1699         /* try to merge extents to the left */
1700
1701         /* time to correct all indexes above */
1702         err = ext4_ext_correct_indexes(handle, inode, path);
1703         if (err)
1704                 goto cleanup;
1705
1706         err = ext4_ext_dirty(handle, inode, path + depth);
1707
1708 cleanup:
1709         if (npath) {
1710                 ext4_ext_drop_refs(npath);
1711                 kfree(npath);
1712         }
1713         ext4_ext_invalidate_cache(inode);
1714         return err;
1715 }
1716
1717 int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1718                         ext4_lblk_t num, ext_prepare_callback func,
1719                         void *cbdata)
1720 {
1721         struct ext4_ext_path *path = NULL;
1722         struct ext4_ext_cache cbex;
1723         struct ext4_extent *ex;
1724         ext4_lblk_t next, start = 0, end = 0;
1725         ext4_lblk_t last = block + num;
1726         int depth, exists, err = 0;
1727
1728         BUG_ON(func == NULL);
1729         BUG_ON(inode == NULL);
1730
1731         while (block < last && block != EXT_MAX_BLOCK) {
1732                 num = last - block;
1733                 /* find extent for this block */
1734                 path = ext4_ext_find_extent(inode, block, path);
1735                 if (IS_ERR(path)) {
1736                         err = PTR_ERR(path);
1737                         path = NULL;
1738                         break;
1739                 }
1740
1741                 depth = ext_depth(inode);
1742                 BUG_ON(path[depth].p_hdr == NULL);
1743                 ex = path[depth].p_ext;
1744                 next = ext4_ext_next_allocated_block(path);
1745
1746                 exists = 0;
1747                 if (!ex) {
1748                         /* there is no extent yet, so try to allocate
1749                          * all requested space */
1750                         start = block;
1751                         end = block + num;
1752                 } else if (le32_to_cpu(ex->ee_block) > block) {
1753                         /* need to allocate space before found extent */
1754                         start = block;
1755                         end = le32_to_cpu(ex->ee_block);
1756                         if (block + num < end)
1757                                 end = block + num;
1758                 } else if (block >= le32_to_cpu(ex->ee_block)
1759                                         + ext4_ext_get_actual_len(ex)) {
1760                         /* need to allocate space after found extent */
1761                         start = block;
1762                         end = block + num;
1763                         if (end >= next)
1764                                 end = next;
1765                 } else if (block >= le32_to_cpu(ex->ee_block)) {
1766                         /*
1767                          * some part of requested space is covered
1768                          * by found extent
1769                          */
1770                         start = block;
1771                         end = le32_to_cpu(ex->ee_block)
1772                                 + ext4_ext_get_actual_len(ex);
1773                         if (block + num < end)
1774                                 end = block + num;
1775                         exists = 1;
1776                 } else {
1777                         BUG();
1778                 }
1779                 BUG_ON(end <= start);
1780
1781                 if (!exists) {
1782                         cbex.ec_block = start;
1783                         cbex.ec_len = end - start;
1784                         cbex.ec_start = 0;
1785                         cbex.ec_type = EXT4_EXT_CACHE_GAP;
1786                 } else {
1787                         cbex.ec_block = le32_to_cpu(ex->ee_block);
1788                         cbex.ec_len = ext4_ext_get_actual_len(ex);
1789                         cbex.ec_start = ext_pblock(ex);
1790                         cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
1791                 }
1792
1793                 BUG_ON(cbex.ec_len == 0);
1794                 err = func(inode, path, &cbex, ex, cbdata);
1795                 ext4_ext_drop_refs(path);
1796
1797                 if (err < 0)
1798                         break;
1799
1800                 if (err == EXT_REPEAT)
1801                         continue;
1802                 else if (err == EXT_BREAK) {
1803                         err = 0;
1804                         break;
1805                 }
1806
1807                 if (ext_depth(inode) != depth) {
1808                         /* depth was changed. we have to realloc path */
1809                         kfree(path);
1810                         path = NULL;
1811                 }
1812
1813                 block = cbex.ec_block + cbex.ec_len;
1814         }
1815
1816         if (path) {
1817                 ext4_ext_drop_refs(path);
1818                 kfree(path);
1819         }
1820
1821         return err;
1822 }
1823
1824 static void
1825 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1826                         __u32 len, ext4_fsblk_t start, int type)
1827 {
1828         struct ext4_ext_cache *cex;
1829         BUG_ON(len == 0);
1830         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1831         cex = &EXT4_I(inode)->i_cached_extent;
1832         cex->ec_type = type;
1833         cex->ec_block = block;
1834         cex->ec_len = len;
1835         cex->ec_start = start;
1836         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1837 }
1838
1839 /*
1840  * ext4_ext_put_gap_in_cache:
1841  * calculate boundaries of the gap that the requested block fits into
1842  * and cache this gap
1843  */
1844 static void
1845 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1846                                 ext4_lblk_t block)
1847 {
1848         int depth = ext_depth(inode);
1849         unsigned long len;
1850         ext4_lblk_t lblock;
1851         struct ext4_extent *ex;
1852
1853         ex = path[depth].p_ext;
1854         if (ex == NULL) {
1855                 /* there is no extent yet, so gap is [0;-] */
1856                 lblock = 0;
1857                 len = EXT_MAX_BLOCK;
1858                 ext_debug("cache gap(whole file):");
1859         } else if (block < le32_to_cpu(ex->ee_block)) {
1860                 lblock = block;
1861                 len = le32_to_cpu(ex->ee_block) - block;
1862                 ext_debug("cache gap(before): %u [%u:%u]",
1863                                 block,
1864                                 le32_to_cpu(ex->ee_block),
1865                                  ext4_ext_get_actual_len(ex));
1866         } else if (block >= le32_to_cpu(ex->ee_block)
1867                         + ext4_ext_get_actual_len(ex)) {
1868                 ext4_lblk_t next;
1869                 lblock = le32_to_cpu(ex->ee_block)
1870                         + ext4_ext_get_actual_len(ex);
1871
1872                 next = ext4_ext_next_allocated_block(path);
1873                 ext_debug("cache gap(after): [%u:%u] %u",
1874                                 le32_to_cpu(ex->ee_block),
1875                                 ext4_ext_get_actual_len(ex),
1876                                 block);
1877                 BUG_ON(next == lblock);
1878                 len = next - lblock;
1879         } else {
1880                 lblock = len = 0;
1881                 BUG();
1882         }
1883
1884         ext_debug(" -> %u:%lu\n", lblock, len);
1885         ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1886 }
1887
1888 static int
1889 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
1890                         struct ext4_extent *ex)
1891 {
1892         struct ext4_ext_cache *cex;
1893         int ret = EXT4_EXT_CACHE_NO;
1894
1895         /* 
1896          * We borrow i_block_reservation_lock to protect i_cached_extent
1897          */
1898         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1899         cex = &EXT4_I(inode)->i_cached_extent;
1900
1901         /* has cache valid data? */
1902         if (cex->ec_type == EXT4_EXT_CACHE_NO)
1903                 goto errout;
1904
1905         BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1906                         cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1907         if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
1908                 ex->ee_block = cpu_to_le32(cex->ec_block);
1909                 ext4_ext_store_pblock(ex, cex->ec_start);
1910                 ex->ee_len = cpu_to_le16(cex->ec_len);
1911                 ext_debug("%u cached by %u:%u:%llu\n",
1912                                 block,
1913                                 cex->ec_block, cex->ec_len, cex->ec_start);
1914                 ret = cex->ec_type;
1915         }
1916 errout:
1917         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1918         return ret;
1919 }
1920
1921 /*
1922  * ext4_ext_rm_idx:
1923  * removes index from the index block.
1924  * It's used in truncate case only, thus all requests are for
1925  * last index in the block only.
1926  */
1927 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1928                         struct ext4_ext_path *path)
1929 {
1930         struct buffer_head *bh;
1931         int err;
1932         ext4_fsblk_t leaf;
1933
1934         /* free index block */
1935         path--;
1936         leaf = idx_pblock(path->p_idx);
1937         BUG_ON(path->p_hdr->eh_entries == 0);
1938         err = ext4_ext_get_access(handle, inode, path);
1939         if (err)
1940                 return err;
1941         le16_add_cpu(&path->p_hdr->eh_entries, -1);
1942         err = ext4_ext_dirty(handle, inode, path);
1943         if (err)
1944                 return err;
1945         ext_debug("index is empty, remove it, free block %llu\n", leaf);
1946         bh = sb_find_get_block(inode->i_sb, leaf);
1947         ext4_forget(handle, 1, inode, bh, leaf);
1948         ext4_free_blocks(handle, inode, leaf, 1, 1);
1949         return err;
1950 }
1951
1952 /*
1953  * ext4_ext_calc_credits_for_single_extent:
1954  * This routine returns max. credits that needed to insert an extent
1955  * to the extent tree.
1956  * When pass the actual path, the caller should calculate credits
1957  * under i_data_sem.
1958  */
1959 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
1960                                                 struct ext4_ext_path *path)
1961 {
1962         if (path) {
1963                 int depth = ext_depth(inode);
1964                 int ret = 0;
1965
1966                 /* probably there is space in leaf? */
1967                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1968                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
1969
1970                         /*
1971                          *  There are some space in the leaf tree, no
1972                          *  need to account for leaf block credit
1973                          *
1974                          *  bitmaps and block group descriptor blocks
1975                          *  and other metadat blocks still need to be
1976                          *  accounted.
1977                          */
1978                         /* 1 bitmap, 1 block group descriptor */
1979                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
1980                         return ret;
1981                 }
1982         }
1983
1984         return ext4_chunk_trans_blocks(inode, nrblocks);
1985 }
1986
1987 /*
1988  * How many index/leaf blocks need to change/allocate to modify nrblocks?
1989  *
1990  * if nrblocks are fit in a single extent (chunk flag is 1), then
1991  * in the worse case, each tree level index/leaf need to be changed
1992  * if the tree split due to insert a new extent, then the old tree
1993  * index/leaf need to be updated too
1994  *
1995  * If the nrblocks are discontiguous, they could cause
1996  * the whole tree split more than once, but this is really rare.
1997  */
1998 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
1999 {
2000         int index;
2001         int depth = ext_depth(inode);
2002
2003         if (chunk)
2004                 index = depth * 2;
2005         else
2006                 index = depth * 3;
2007
2008         return index;
2009 }
2010
2011 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2012                                 struct ext4_extent *ex,
2013                                 ext4_lblk_t from, ext4_lblk_t to)
2014 {
2015         struct buffer_head *bh;
2016         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2017         int i, metadata = 0;
2018
2019         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2020                 metadata = 1;
2021 #ifdef EXTENTS_STATS
2022         {
2023                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2024                 spin_lock(&sbi->s_ext_stats_lock);
2025                 sbi->s_ext_blocks += ee_len;
2026                 sbi->s_ext_extents++;
2027                 if (ee_len < sbi->s_ext_min)
2028                         sbi->s_ext_min = ee_len;
2029                 if (ee_len > sbi->s_ext_max)
2030                         sbi->s_ext_max = ee_len;
2031                 if (ext_depth(inode) > sbi->s_depth_max)
2032                         sbi->s_depth_max = ext_depth(inode);
2033                 spin_unlock(&sbi->s_ext_stats_lock);
2034         }
2035 #endif
2036         if (from >= le32_to_cpu(ex->ee_block)
2037             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2038                 /* tail removal */
2039                 ext4_lblk_t num;
2040                 ext4_fsblk_t start;
2041
2042                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2043                 start = ext_pblock(ex) + ee_len - num;
2044                 ext_debug("free last %u blocks starting %llu\n", num, start);
2045                 for (i = 0; i < num; i++) {
2046                         bh = sb_find_get_block(inode->i_sb, start + i);
2047                         ext4_forget(handle, 0, inode, bh, start + i);
2048                 }
2049                 ext4_free_blocks(handle, inode, start, num, metadata);
2050         } else if (from == le32_to_cpu(ex->ee_block)
2051                    && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2052                 printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n",
2053                         from, to, le32_to_cpu(ex->ee_block), ee_len);
2054         } else {
2055                 printk(KERN_INFO "strange request: removal(2) "
2056                                 "%u-%u from %u:%u\n",
2057                                 from, to, le32_to_cpu(ex->ee_block), ee_len);
2058         }
2059         return 0;
2060 }
2061
2062 static int
2063 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2064                 struct ext4_ext_path *path, ext4_lblk_t start)
2065 {
2066         int err = 0, correct_index = 0;
2067         int depth = ext_depth(inode), credits;
2068         struct ext4_extent_header *eh;
2069         ext4_lblk_t a, b, block;
2070         unsigned num;
2071         ext4_lblk_t ex_ee_block;
2072         unsigned short ex_ee_len;
2073         unsigned uninitialized = 0;
2074         struct ext4_extent *ex;
2075
2076         /* the header must be checked already in ext4_ext_remove_space() */
2077         ext_debug("truncate since %u in leaf\n", start);
2078         if (!path[depth].p_hdr)
2079                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2080         eh = path[depth].p_hdr;
2081         BUG_ON(eh == NULL);
2082
2083         /* find where to start removing */
2084         ex = EXT_LAST_EXTENT(eh);
2085
2086         ex_ee_block = le32_to_cpu(ex->ee_block);
2087         ex_ee_len = ext4_ext_get_actual_len(ex);
2088
2089         while (ex >= EXT_FIRST_EXTENT(eh) &&
2090                         ex_ee_block + ex_ee_len > start) {
2091
2092                 if (ext4_ext_is_uninitialized(ex))
2093                         uninitialized = 1;
2094                 else
2095                         uninitialized = 0;
2096
2097                 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
2098                 path[depth].p_ext = ex;
2099
2100                 a = ex_ee_block > start ? ex_ee_block : start;
2101                 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
2102                         ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
2103
2104                 ext_debug("  border %u:%u\n", a, b);
2105
2106                 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
2107                         block = 0;
2108                         num = 0;
2109                         BUG();
2110                 } else if (a != ex_ee_block) {
2111                         /* remove tail of the extent */
2112                         block = ex_ee_block;
2113                         num = a - block;
2114                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2115                         /* remove head of the extent */
2116                         block = a;
2117                         num = b - a;
2118                         /* there is no "make a hole" API yet */
2119                         BUG();
2120                 } else {
2121                         /* remove whole extent: excellent! */
2122                         block = ex_ee_block;
2123                         num = 0;
2124                         BUG_ON(a != ex_ee_block);
2125                         BUG_ON(b != ex_ee_block + ex_ee_len - 1);
2126                 }
2127
2128                 /*
2129                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2130                  * descriptor) for each block group; assume two block
2131                  * groups plus ex_ee_len/blocks_per_block_group for
2132                  * the worst case
2133                  */
2134                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2135                 if (ex == EXT_FIRST_EXTENT(eh)) {
2136                         correct_index = 1;
2137                         credits += (ext_depth(inode)) + 1;
2138                 }
2139                 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
2140
2141                 err = ext4_ext_journal_restart(handle, credits);
2142                 if (err)
2143                         goto out;
2144
2145                 err = ext4_ext_get_access(handle, inode, path + depth);
2146                 if (err)
2147                         goto out;
2148
2149                 err = ext4_remove_blocks(handle, inode, ex, a, b);
2150                 if (err)
2151                         goto out;
2152
2153                 if (num == 0) {
2154                         /* this extent is removed; mark slot entirely unused */
2155                         ext4_ext_store_pblock(ex, 0);
2156                         le16_add_cpu(&eh->eh_entries, -1);
2157                 }
2158
2159                 ex->ee_block = cpu_to_le32(block);
2160                 ex->ee_len = cpu_to_le16(num);
2161                 /*
2162                  * Do not mark uninitialized if all the blocks in the
2163                  * extent have been removed.
2164                  */
2165                 if (uninitialized && num)
2166                         ext4_ext_mark_uninitialized(ex);
2167
2168                 err = ext4_ext_dirty(handle, inode, path + depth);
2169                 if (err)
2170                         goto out;
2171
2172                 ext_debug("new extent: %u:%u:%llu\n", block, num,
2173                                 ext_pblock(ex));
2174                 ex--;
2175                 ex_ee_block = le32_to_cpu(ex->ee_block);
2176                 ex_ee_len = ext4_ext_get_actual_len(ex);
2177         }
2178
2179         if (correct_index && eh->eh_entries)
2180                 err = ext4_ext_correct_indexes(handle, inode, path);
2181
2182         /* if this leaf is free, then we should
2183          * remove it from index block above */
2184         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2185                 err = ext4_ext_rm_idx(handle, inode, path + depth);
2186
2187 out:
2188         return err;
2189 }
2190
2191 /*
2192  * ext4_ext_more_to_rm:
2193  * returns 1 if current index has to be freed (even partial)
2194  */
2195 static int
2196 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2197 {
2198         BUG_ON(path->p_idx == NULL);
2199
2200         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2201                 return 0;
2202
2203         /*
2204          * if truncate on deeper level happened, it wasn't partial,
2205          * so we have to consider current index for truncation
2206          */
2207         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2208                 return 0;
2209         return 1;
2210 }
2211
2212 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
2213 {
2214         struct super_block *sb = inode->i_sb;
2215         int depth = ext_depth(inode);
2216         struct ext4_ext_path *path;
2217         handle_t *handle;
2218         int i = 0, err = 0;
2219
2220         ext_debug("truncate since %u\n", start);
2221
2222         /* probably first extent we're gonna free will be last in block */
2223         handle = ext4_journal_start(inode, depth + 1);
2224         if (IS_ERR(handle))
2225                 return PTR_ERR(handle);
2226
2227         ext4_ext_invalidate_cache(inode);
2228
2229         /*
2230          * We start scanning from right side, freeing all the blocks
2231          * after i_size and walking into the tree depth-wise.
2232          */
2233         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
2234         if (path == NULL) {
2235                 ext4_journal_stop(handle);
2236                 return -ENOMEM;
2237         }
2238         path[0].p_hdr = ext_inode_hdr(inode);
2239         if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2240                 err = -EIO;
2241                 goto out;
2242         }
2243         path[0].p_depth = depth;
2244
2245         while (i >= 0 && err == 0) {
2246                 if (i == depth) {
2247                         /* this is leaf block */
2248                         err = ext4_ext_rm_leaf(handle, inode, path, start);
2249                         /* root level has p_bh == NULL, brelse() eats this */
2250                         brelse(path[i].p_bh);
2251                         path[i].p_bh = NULL;
2252                         i--;
2253                         continue;
2254                 }
2255
2256                 /* this is index block */
2257                 if (!path[i].p_hdr) {
2258                         ext_debug("initialize header\n");
2259                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2260                 }
2261
2262                 if (!path[i].p_idx) {
2263                         /* this level hasn't been touched yet */
2264                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2265                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2266                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2267                                   path[i].p_hdr,
2268                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2269                 } else {
2270                         /* we were already here, see at next index */
2271                         path[i].p_idx--;
2272                 }
2273
2274                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2275                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2276                                 path[i].p_idx);
2277                 if (ext4_ext_more_to_rm(path + i)) {
2278                         struct buffer_head *bh;
2279                         /* go to the next level */
2280                         ext_debug("move to level %d (block %llu)\n",
2281                                   i + 1, idx_pblock(path[i].p_idx));
2282                         memset(path + i + 1, 0, sizeof(*path));
2283                         bh = sb_bread(sb, idx_pblock(path[i].p_idx));
2284                         if (!bh) {
2285                                 /* should we reset i_size? */
2286                                 err = -EIO;
2287                                 break;
2288                         }
2289                         if (WARN_ON(i + 1 > depth)) {
2290                                 err = -EIO;
2291                                 break;
2292                         }
2293                         if (ext4_ext_check(inode, ext_block_hdr(bh),
2294                                                         depth - i - 1)) {
2295                                 err = -EIO;
2296                                 break;
2297                         }
2298                         path[i + 1].p_bh = bh;
2299
2300                         /* save actual number of indexes since this
2301                          * number is changed at the next iteration */
2302                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2303                         i++;
2304                 } else {
2305                         /* we finished processing this index, go up */
2306                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2307                                 /* index is empty, remove it;
2308                                  * handle must be already prepared by the
2309                                  * truncatei_leaf() */
2310                                 err = ext4_ext_rm_idx(handle, inode, path + i);
2311                         }
2312                         /* root level has p_bh == NULL, brelse() eats this */
2313                         brelse(path[i].p_bh);
2314                         path[i].p_bh = NULL;
2315                         i--;
2316                         ext_debug("return to level %d\n", i);
2317                 }
2318         }
2319
2320         /* TODO: flexible tree reduction should be here */
2321         if (path->p_hdr->eh_entries == 0) {
2322                 /*
2323                  * truncate to zero freed all the tree,
2324                  * so we need to correct eh_depth
2325                  */
2326                 err = ext4_ext_get_access(handle, inode, path);
2327                 if (err == 0) {
2328                         ext_inode_hdr(inode)->eh_depth = 0;
2329                         ext_inode_hdr(inode)->eh_max =
2330                                 cpu_to_le16(ext4_ext_space_root(inode));
2331                         err = ext4_ext_dirty(handle, inode, path);
2332                 }
2333         }
2334 out:
2335         ext4_ext_drop_refs(path);
2336         kfree(path);
2337         ext4_journal_stop(handle);
2338
2339         return err;
2340 }
2341
2342 /*
2343  * called at mount time
2344  */
2345 void ext4_ext_init(struct super_block *sb)
2346 {
2347         /*
2348          * possible initialization would be here
2349          */
2350
2351         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2352                 printk(KERN_INFO "EXT4-fs: file extents enabled");
2353 #ifdef AGGRESSIVE_TEST
2354                 printk(", aggressive tests");
2355 #endif
2356 #ifdef CHECK_BINSEARCH
2357                 printk(", check binsearch");
2358 #endif
2359 #ifdef EXTENTS_STATS
2360                 printk(", stats");
2361 #endif
2362                 printk("\n");
2363 #ifdef EXTENTS_STATS
2364                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2365                 EXT4_SB(sb)->s_ext_min = 1 << 30;
2366                 EXT4_SB(sb)->s_ext_max = 0;
2367 #endif
2368         }
2369 }
2370
2371 /*
2372  * called at umount time
2373  */
2374 void ext4_ext_release(struct super_block *sb)
2375 {
2376         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2377                 return;
2378
2379 #ifdef EXTENTS_STATS
2380         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2381                 struct ext4_sb_info *sbi = EXT4_SB(sb);
2382                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2383                         sbi->s_ext_blocks, sbi->s_ext_extents,
2384                         sbi->s_ext_blocks / sbi->s_ext_extents);
2385                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2386                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2387         }
2388 #endif
2389 }
2390
2391 static void bi_complete(struct bio *bio, int error)
2392 {
2393         complete((struct completion *)bio->bi_private);
2394 }
2395
2396 /* FIXME!! we need to try to merge to left or right after zero-out  */
2397 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2398 {
2399         int ret = -EIO;
2400         struct bio *bio;
2401         int blkbits, blocksize;
2402         sector_t ee_pblock;
2403         struct completion event;
2404         unsigned int ee_len, len, done, offset;
2405
2406
2407         blkbits   = inode->i_blkbits;
2408         blocksize = inode->i_sb->s_blocksize;
2409         ee_len    = ext4_ext_get_actual_len(ex);
2410         ee_pblock = ext_pblock(ex);
2411
2412         /* convert ee_pblock to 512 byte sectors */
2413         ee_pblock = ee_pblock << (blkbits - 9);
2414
2415         while (ee_len > 0) {
2416
2417                 if (ee_len > BIO_MAX_PAGES)
2418                         len = BIO_MAX_PAGES;
2419                 else
2420                         len = ee_len;
2421
2422                 bio = bio_alloc(GFP_NOIO, len);
2423                 bio->bi_sector = ee_pblock;
2424                 bio->bi_bdev   = inode->i_sb->s_bdev;
2425
2426                 done = 0;
2427                 offset = 0;
2428                 while (done < len) {
2429                         ret = bio_add_page(bio, ZERO_PAGE(0),
2430                                                         blocksize, offset);
2431                         if (ret != blocksize) {
2432                                 /*
2433                                  * We can't add any more pages because of
2434                                  * hardware limitations.  Start a new bio.
2435                                  */
2436                                 break;
2437                         }
2438                         done++;
2439                         offset += blocksize;
2440                         if (offset >= PAGE_CACHE_SIZE)
2441                                 offset = 0;
2442                 }
2443
2444                 init_completion(&event);
2445                 bio->bi_private = &event;
2446                 bio->bi_end_io = bi_complete;
2447                 submit_bio(WRITE, bio);
2448                 wait_for_completion(&event);
2449
2450                 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
2451                         ret = 0;
2452                 else {
2453                         ret = -EIO;
2454                         break;
2455                 }
2456                 bio_put(bio);
2457                 ee_len    -= done;
2458                 ee_pblock += done  << (blkbits - 9);
2459         }
2460         return ret;
2461 }
2462
2463 #define EXT4_EXT_ZERO_LEN 7
2464
2465 /*
2466  * This function is called by ext4_ext_get_blocks() if someone tries to write
2467  * to an uninitialized extent. It may result in splitting the uninitialized
2468  * extent into multiple extents (upto three - one initialized and two
2469  * uninitialized).
2470  * There are three possibilities:
2471  *   a> There is no split required: Entire extent should be initialized
2472  *   b> Splits in two extents: Write is happening at either end of the extent
2473  *   c> Splits in three extents: Somone is writing in middle of the extent
2474  */
2475 static int ext4_ext_convert_to_initialized(handle_t *handle,
2476                                                 struct inode *inode,
2477                                                 struct ext4_ext_path *path,
2478                                                 ext4_lblk_t iblock,
2479                                                 unsigned int max_blocks)
2480 {
2481         struct ext4_extent *ex, newex, orig_ex;
2482         struct ext4_extent *ex1 = NULL;
2483         struct ext4_extent *ex2 = NULL;
2484         struct ext4_extent *ex3 = NULL;
2485         struct ext4_extent_header *eh;
2486         ext4_lblk_t ee_block;
2487         unsigned int allocated, ee_len, depth;
2488         ext4_fsblk_t newblock;
2489         int err = 0;
2490         int ret = 0;
2491
2492         depth = ext_depth(inode);
2493         eh = path[depth].p_hdr;
2494         ex = path[depth].p_ext;
2495         ee_block = le32_to_cpu(ex->ee_block);
2496         ee_len = ext4_ext_get_actual_len(ex);
2497         allocated = ee_len - (iblock - ee_block);
2498         newblock = iblock - ee_block + ext_pblock(ex);
2499         ex2 = ex;
2500         orig_ex.ee_block = ex->ee_block;
2501         orig_ex.ee_len   = cpu_to_le16(ee_len);
2502         ext4_ext_store_pblock(&orig_ex, ext_pblock(ex));
2503
2504         err = ext4_ext_get_access(handle, inode, path + depth);
2505         if (err)
2506                 goto out;
2507         /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
2508         if (ee_len <= 2*EXT4_EXT_ZERO_LEN) {
2509                 err =  ext4_ext_zeroout(inode, &orig_ex);
2510                 if (err)
2511                         goto fix_extent_len;
2512                 /* update the extent length and mark as initialized */
2513                 ex->ee_block = orig_ex.ee_block;
2514                 ex->ee_len   = orig_ex.ee_len;
2515                 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2516                 ext4_ext_dirty(handle, inode, path + depth);
2517                 /* zeroed the full extent */
2518                 return allocated;
2519         }
2520
2521         /* ex1: ee_block to iblock - 1 : uninitialized */
2522         if (iblock > ee_block) {
2523                 ex1 = ex;
2524                 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2525                 ext4_ext_mark_uninitialized(ex1);
2526                 ex2 = &newex;
2527         }
2528         /*
2529          * for sanity, update the length of the ex2 extent before
2530          * we insert ex3, if ex1 is NULL. This is to avoid temporary
2531          * overlap of blocks.
2532          */
2533         if (!ex1 && allocated > max_blocks)
2534                 ex2->ee_len = cpu_to_le16(max_blocks);
2535         /* ex3: to ee_block + ee_len : uninitialised */
2536         if (allocated > max_blocks) {
2537                 unsigned int newdepth;
2538                 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
2539                 if (allocated <= EXT4_EXT_ZERO_LEN) {
2540                         /*
2541                          * iblock == ee_block is handled by the zerouout
2542                          * at the beginning.
2543                          * Mark first half uninitialized.
2544                          * Mark second half initialized and zero out the
2545                          * initialized extent
2546                          */
2547                         ex->ee_block = orig_ex.ee_block;
2548                         ex->ee_len   = cpu_to_le16(ee_len - allocated);
2549                         ext4_ext_mark_uninitialized(ex);
2550                         ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2551                         ext4_ext_dirty(handle, inode, path + depth);
2552
2553                         ex3 = &newex;
2554                         ex3->ee_block = cpu_to_le32(iblock);
2555                         ext4_ext_store_pblock(ex3, newblock);
2556                         ex3->ee_len = cpu_to_le16(allocated);
2557                         err = ext4_ext_insert_extent(handle, inode, path, ex3);
2558                         if (err == -ENOSPC) {
2559                                 err =  ext4_ext_zeroout(inode, &orig_ex);
2560                                 if (err)
2561                                         goto fix_extent_len;
2562                                 ex->ee_block = orig_ex.ee_block;
2563                                 ex->ee_len   = orig_ex.ee_len;
2564                                 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2565                                 ext4_ext_dirty(handle, inode, path + depth);
2566                                 /* blocks available from iblock */
2567                                 return allocated;
2568
2569                         } else if (err)
2570                                 goto fix_extent_len;
2571
2572                         /*
2573                          * We need to zero out the second half because
2574                          * an fallocate request can update file size and
2575                          * converting the second half to initialized extent
2576                          * implies that we can leak some junk data to user
2577                          * space.
2578                          */
2579                         err =  ext4_ext_zeroout(inode, ex3);
2580                         if (err) {
2581                                 /*
2582                                  * We should actually mark the
2583                                  * second half as uninit and return error
2584                                  * Insert would have changed the extent
2585                                  */
2586                                 depth = ext_depth(inode);
2587                                 ext4_ext_drop_refs(path);
2588                                 path = ext4_ext_find_extent(inode,
2589                                                                 iblock, path);
2590                                 if (IS_ERR(path)) {
2591                                         err = PTR_ERR(path);
2592                                         return err;
2593                                 }
2594                                 /* get the second half extent details */
2595                                 ex = path[depth].p_ext;
2596                                 err = ext4_ext_get_access(handle, inode,
2597                                                                 path + depth);
2598                                 if (err)
2599                                         return err;
2600                                 ext4_ext_mark_uninitialized(ex);
2601                                 ext4_ext_dirty(handle, inode, path + depth);
2602                                 return err;
2603                         }
2604
2605                         /* zeroed the second half */
2606                         return allocated;
2607                 }
2608                 ex3 = &newex;
2609                 ex3->ee_block = cpu_to_le32(iblock + max_blocks);
2610                 ext4_ext_store_pblock(ex3, newblock + max_blocks);
2611                 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
2612                 ext4_ext_mark_uninitialized(ex3);
2613                 err = ext4_ext_insert_extent(handle, inode, path, ex3);
2614                 if (err == -ENOSPC) {
2615                         err =  ext4_ext_zeroout(inode, &orig_ex);
2616                         if (err)
2617                                 goto fix_extent_len;
2618                         /* update the extent length and mark as initialized */
2619                         ex->ee_block = orig_ex.ee_block;
2620                         ex->ee_len   = orig_ex.ee_len;
2621                         ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2622                         ext4_ext_dirty(handle, inode, path + depth);
2623                         /* zeroed the full extent */
2624                         /* blocks available from iblock */
2625                         return allocated;
2626
2627                 } else if (err)
2628                         goto fix_extent_len;
2629                 /*
2630                  * The depth, and hence eh & ex might change
2631                  * as part of the insert above.
2632                  */
2633                 newdepth = ext_depth(inode);
2634                 /*
2635                  * update the extent length after successful insert of the
2636                  * split extent
2637                  */
2638                 orig_ex.ee_len = cpu_to_le16(ee_len -
2639                                                 ext4_ext_get_actual_len(ex3));
2640                 depth = newdepth;
2641                 ext4_ext_drop_refs(path);
2642                 path = ext4_ext_find_extent(inode, iblock, path);
2643                 if (IS_ERR(path)) {
2644                         err = PTR_ERR(path);
2645                         goto out;
2646                 }
2647                 eh = path[depth].p_hdr;
2648                 ex = path[depth].p_ext;
2649                 if (ex2 != &newex)
2650                         ex2 = ex;
2651
2652                 err = ext4_ext_get_access(handle, inode, path + depth);
2653                 if (err)
2654                         goto out;
2655
2656                 allocated = max_blocks;
2657
2658                 /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying
2659                  * to insert a extent in the middle zerout directly
2660                  * otherwise give the extent a chance to merge to left
2661                  */
2662                 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN &&
2663                                                         iblock != ee_block) {
2664                         err =  ext4_ext_zeroout(inode, &orig_ex);
2665                         if (err)
2666                                 goto fix_extent_len;
2667                         /* update the extent length and mark as initialized */
2668                         ex->ee_block = orig_ex.ee_block;
2669                         ex->ee_len   = orig_ex.ee_len;
2670                         ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2671                         ext4_ext_dirty(handle, inode, path + depth);
2672                         /* zero out the first half */
2673                         /* blocks available from iblock */
2674                         return allocated;
2675                 }
2676         }
2677         /*
2678          * If there was a change of depth as part of the
2679          * insertion of ex3 above, we need to update the length
2680          * of the ex1 extent again here
2681          */
2682         if (ex1 && ex1 != ex) {
2683                 ex1 = ex;
2684                 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2685                 ext4_ext_mark_uninitialized(ex1);
2686                 ex2 = &newex;
2687         }
2688         /* ex2: iblock to iblock + maxblocks-1 : initialised */
2689         ex2->ee_block = cpu_to_le32(iblock);
2690         ext4_ext_store_pblock(ex2, newblock);
2691         ex2->ee_len = cpu_to_le16(allocated);
2692         if (ex2 != ex)
2693                 goto insert;
2694         /*
2695          * New (initialized) extent starts from the first block
2696          * in the current extent. i.e., ex2 == ex
2697          * We have to see if it can be merged with the extent
2698          * on the left.
2699          */
2700         if (ex2 > EXT_FIRST_EXTENT(eh)) {
2701                 /*
2702                  * To merge left, pass "ex2 - 1" to try_to_merge(),
2703                  * since it merges towards right _only_.
2704                  */
2705                 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
2706                 if (ret) {
2707                         err = ext4_ext_correct_indexes(handle, inode, path);
2708                         if (err)
2709                                 goto out;
2710                         depth = ext_depth(inode);
2711                         ex2--;
2712                 }
2713         }
2714         /*
2715          * Try to Merge towards right. This might be required
2716          * only when the whole extent is being written to.
2717          * i.e. ex2 == ex and ex3 == NULL.
2718          */
2719         if (!ex3) {
2720                 ret = ext4_ext_try_to_merge(inode, path, ex2);
2721                 if (ret) {
2722                         err = ext4_ext_correct_indexes(handle, inode, path);
2723                         if (err)
2724                                 goto out;
2725                 }
2726         }
2727         /* Mark modified extent as dirty */
2728         err = ext4_ext_dirty(handle, inode, path + depth);
2729         goto out;
2730 insert:
2731         err = ext4_ext_insert_extent(handle, inode, path, &newex);
2732         if (err == -ENOSPC) {
2733                 err =  ext4_ext_zeroout(inode, &orig_ex);
2734                 if (err)
2735                         goto fix_extent_len;
2736                 /* update the extent length and mark as initialized */
2737                 ex->ee_block = orig_ex.ee_block;
2738                 ex->ee_len   = orig_ex.ee_len;
2739                 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2740                 ext4_ext_dirty(handle, inode, path + depth);
2741                 /* zero out the first half */
2742                 return allocated;
2743         } else if (err)
2744                 goto fix_extent_len;
2745 out:
2746         return err ? err : allocated;
2747
2748 fix_extent_len:
2749         ex->ee_block = orig_ex.ee_block;
2750         ex->ee_len   = orig_ex.ee_len;
2751         ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
2752         ext4_ext_mark_uninitialized(ex);
2753         ext4_ext_dirty(handle, inode, path + depth);
2754         return err;
2755 }
2756
2757 /*
2758  * Block allocation/map/preallocation routine for extents based files
2759  *
2760  *
2761  * Need to be called with
2762  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
2763  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
2764  *
2765  * return > 0, number of of blocks already mapped/allocated
2766  *          if create == 0 and these are pre-allocated blocks
2767  *              buffer head is unmapped
2768  *          otherwise blocks are mapped
2769  *
2770  * return = 0, if plain look up failed (blocks have not been allocated)
2771  *          buffer head is unmapped
2772  *
2773  * return < 0, error case.
2774  */
2775 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
2776                         ext4_lblk_t iblock,
2777                         unsigned int max_blocks, struct buffer_head *bh_result,
2778                         int flags)
2779 {
2780         struct ext4_ext_path *path = NULL;
2781         struct ext4_extent_header *eh;
2782         struct ext4_extent newex, *ex;
2783         ext4_fsblk_t newblock;
2784         int err = 0, depth, ret, cache_type;
2785         unsigned int allocated = 0;
2786         struct ext4_allocation_request ar;
2787
2788         __clear_bit(BH_New, &bh_result->b_state);
2789         ext_debug("blocks %u/%u requested for inode %u\n",
2790                         iblock, max_blocks, inode->i_ino);
2791
2792         /* check in cache */
2793         cache_type = ext4_ext_in_cache(inode, iblock, &newex);
2794         if (cache_type) {
2795                 if (cache_type == EXT4_EXT_CACHE_GAP) {
2796                         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
2797                                 /*
2798                                  * block isn't allocated yet and
2799                                  * user doesn't want to allocate it
2800                                  */
2801                                 goto out2;
2802                         }
2803                         /* we should allocate requested block */
2804                 } else if (cache_type == EXT4_EXT_CACHE_EXTENT) {
2805                         /* block is already allocated */
2806                         newblock = iblock
2807                                    - le32_to_cpu(newex.ee_block)
2808                                    + ext_pblock(&newex);
2809                         /* number of remaining blocks in the extent */
2810                         allocated = ext4_ext_get_actual_len(&newex) -
2811                                         (iblock - le32_to_cpu(newex.ee_block));
2812                         goto out;
2813                 } else {
2814                         BUG();
2815                 }
2816         }
2817
2818         /* find extent for this block */
2819         path = ext4_ext_find_extent(inode, iblock, NULL);
2820         if (IS_ERR(path)) {
2821                 err = PTR_ERR(path);
2822                 path = NULL;
2823                 goto out2;
2824         }
2825
2826         depth = ext_depth(inode);
2827
2828         /*
2829          * consistent leaf must not be empty;
2830          * this situation is possible, though, _during_ tree modification;
2831          * this is why assert can't be put in ext4_ext_find_extent()
2832          */
2833         BUG_ON(path[depth].p_ext == NULL && depth != 0);
2834         eh = path[depth].p_hdr;
2835
2836         ex = path[depth].p_ext;
2837         if (ex) {
2838                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
2839                 ext4_fsblk_t ee_start = ext_pblock(ex);
2840                 unsigned short ee_len;
2841
2842                 /*
2843                  * Uninitialized extents are treated as holes, except that
2844                  * we split out initialized portions during a write.
2845                  */
2846                 ee_len = ext4_ext_get_actual_len(ex);
2847                 /* if found extent covers block, simply return it */
2848                 if (iblock >= ee_block && iblock < ee_block + ee_len) {
2849                         newblock = iblock - ee_block + ee_start;
2850                         /* number of remaining blocks in the extent */
2851                         allocated = ee_len - (iblock - ee_block);
2852                         ext_debug("%u fit into %lu:%d -> %llu\n", iblock,
2853                                         ee_block, ee_len, newblock);
2854
2855                         /* Do not put uninitialized extent in the cache */
2856                         if (!ext4_ext_is_uninitialized(ex)) {
2857                                 ext4_ext_put_in_cache(inode, ee_block,
2858                                                         ee_len, ee_start,
2859                                                         EXT4_EXT_CACHE_EXTENT);
2860                                 goto out;
2861                         }
2862                         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
2863                                 goto out;
2864                         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
2865                                 if (allocated > max_blocks)
2866                                         allocated = max_blocks;
2867                                 /*
2868                                  * We have blocks reserved already.  We
2869                                  * return allocated blocks so that delalloc
2870                                  * won't do block reservation for us.  But
2871                                  * the buffer head will be unmapped so that
2872                                  * a read from the block returns 0s.
2873                                  */
2874                                 set_buffer_unwritten(bh_result);
2875                                 bh_result->b_bdev = inode->i_sb->s_bdev;
2876                                 bh_result->b_blocknr = newblock;
2877                                 goto out2;
2878                         }
2879
2880                         ret = ext4_ext_convert_to_initialized(handle, inode,
2881                                                                 path, iblock,
2882                                                                 max_blocks);
2883                         if (ret <= 0) {
2884                                 err = ret;
2885                                 goto out2;
2886                         } else
2887                                 allocated = ret;
2888                         goto outnew;
2889                 }
2890         }
2891
2892         /*
2893          * requested block isn't allocated yet;
2894          * we couldn't try to create block if create flag is zero
2895          */
2896         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
2897                 /*
2898                  * put just found gap into cache to speed up
2899                  * subsequent requests
2900                  */
2901                 ext4_ext_put_gap_in_cache(inode, path, iblock);
2902                 goto out2;
2903         }
2904         /*
2905          * Okay, we need to do block allocation.
2906          */
2907
2908         /* find neighbour allocated blocks */
2909         ar.lleft = iblock;
2910         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
2911         if (err)
2912                 goto out2;
2913         ar.lright = iblock;
2914         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
2915         if (err)
2916                 goto out2;
2917
2918         /*
2919          * See if request is beyond maximum number of blocks we can have in
2920          * a single extent. For an initialized extent this limit is
2921          * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
2922          * EXT_UNINIT_MAX_LEN.
2923          */
2924         if (max_blocks > EXT_INIT_MAX_LEN &&
2925             !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
2926                 max_blocks = EXT_INIT_MAX_LEN;
2927         else if (max_blocks > EXT_UNINIT_MAX_LEN &&
2928                  (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
2929                 max_blocks = EXT_UNINIT_MAX_LEN;
2930
2931         /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
2932         newex.ee_block = cpu_to_le32(iblock);
2933         newex.ee_len = cpu_to_le16(max_blocks);
2934         err = ext4_ext_check_overlap(inode, &newex, path);
2935         if (err)
2936                 allocated = ext4_ext_get_actual_len(&newex);
2937         else
2938                 allocated = max_blocks;
2939
2940         /* allocate new block */
2941         ar.inode = inode;
2942         ar.goal = ext4_ext_find_goal(inode, path, iblock);
2943         ar.logical = iblock;
2944         ar.len = allocated;
2945         if (S_ISREG(inode->i_mode))
2946                 ar.flags = EXT4_MB_HINT_DATA;
2947         else
2948                 /* disable in-core preallocation for non-regular files */
2949                 ar.flags = 0;
2950         newblock = ext4_mb_new_blocks(handle, &ar, &err);
2951         if (!newblock)
2952                 goto out2;
2953         ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
2954                   ar.goal, newblock, allocated);
2955
2956         /* try to insert new extent into found leaf and return */
2957         ext4_ext_store_pblock(&newex, newblock);
2958         newex.ee_len = cpu_to_le16(ar.len);
2959         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)  /* Mark uninitialized */
2960                 ext4_ext_mark_uninitialized(&newex);
2961         err = ext4_ext_insert_extent(handle, inode, path, &newex);
2962         if (err) {
2963                 /* free data blocks we just allocated */
2964                 /* not a good idea to call discard here directly,
2965                  * but otherwise we'd need to call it every free() */
2966                 ext4_discard_preallocations(inode);
2967                 ext4_free_blocks(handle, inode, ext_pblock(&newex),
2968                                         ext4_ext_get_actual_len(&newex), 0);
2969                 goto out2;
2970         }
2971
2972         /* previous routine could use block we allocated */
2973         newblock = ext_pblock(&newex);
2974         allocated = ext4_ext_get_actual_len(&newex);
2975 outnew:
2976         set_buffer_new(bh_result);
2977
2978         /* Cache only when it is _not_ an uninitialized extent */
2979         if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)
2980                 ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
2981                                                 EXT4_EXT_CACHE_EXTENT);
2982 out:
2983         if (allocated > max_blocks)
2984                 allocated = max_blocks;
2985         ext4_ext_show_leaf(inode, path);
2986         set_buffer_mapped(bh_result);
2987         bh_result->b_bdev = inode->i_sb->s_bdev;
2988         bh_result->b_blocknr = newblock;
2989 out2:
2990         if (path) {
2991                 ext4_ext_drop_refs(path);
2992                 kfree(path);
2993         }
2994         return err ? err : allocated;
2995 }
2996
2997 void ext4_ext_truncate(struct inode *inode)
2998 {
2999         struct address_space *mapping = inode->i_mapping;
3000         struct super_block *sb = inode->i_sb;
3001         ext4_lblk_t last_block;
3002         handle_t *handle;
3003         int err = 0;
3004
3005         /*
3006          * probably first extent we're gonna free will be last in block
3007          */
3008         err = ext4_writepage_trans_blocks(inode);
3009         handle = ext4_journal_start(inode, err);
3010         if (IS_ERR(handle))
3011                 return;
3012
3013         if (inode->i_size & (sb->s_blocksize - 1))
3014                 ext4_block_truncate_page(handle, mapping, inode->i_size);
3015
3016         if (ext4_orphan_add(handle, inode))
3017                 goto out_stop;
3018
3019         down_write(&EXT4_I(inode)->i_data_sem);
3020         ext4_ext_invalidate_cache(inode);
3021
3022         ext4_discard_preallocations(inode);
3023
3024         /*
3025          * TODO: optimization is possible here.
3026          * Probably we need not scan at all,
3027          * because page truncation is enough.
3028          */
3029
3030         /* we have to know where to truncate from in crash case */
3031         EXT4_I(inode)->i_disksize = inode->i_size;
3032         ext4_mark_inode_dirty(handle, inode);
3033
3034         last_block = (inode->i_size + sb->s_blocksize - 1)
3035                         >> EXT4_BLOCK_SIZE_BITS(sb);
3036         err = ext4_ext_remove_space(inode, last_block);
3037
3038         /* In a multi-transaction truncate, we only make the final
3039          * transaction synchronous.
3040          */
3041         if (IS_SYNC(inode))
3042                 ext4_handle_sync(handle);
3043
3044 out_stop:
3045         up_write(&EXT4_I(inode)->i_data_sem);
3046         /*
3047          * If this was a simple ftruncate() and the file will remain alive,
3048          * then we need to clear up the orphan record which we created above.
3049          * However, if this was a real unlink then we were called by
3050          * ext4_delete_inode(), and we allow that function to clean up the
3051          * orphan info for us.
3052          */
3053         if (inode->i_nlink)
3054                 ext4_orphan_del(handle, inode);
3055
3056         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3057         ext4_mark_inode_dirty(handle, inode);
3058         ext4_journal_stop(handle);
3059 }
3060
3061 static void ext4_falloc_update_inode(struct inode *inode,
3062                                 int mode, loff_t new_size, int update_ctime)
3063 {
3064         struct timespec now;
3065
3066         if (update_ctime) {
3067                 now = current_fs_time(inode->i_sb);
3068                 if (!timespec_equal(&inode->i_ctime, &now))
3069                         inode->i_ctime = now;
3070         }
3071         /*
3072          * Update only when preallocation was requested beyond
3073          * the file size.
3074          */
3075         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3076                 if (new_size > i_size_read(inode))
3077                         i_size_write(inode, new_size);
3078                 if (new_size > EXT4_I(inode)->i_disksize)
3079                         ext4_update_i_disksize(inode, new_size);
3080         }
3081
3082 }
3083
3084 /*
3085  * preallocate space for a file. This implements ext4's fallocate inode
3086  * operation, which gets called from sys_fallocate system call.
3087  * For block-mapped files, posix_fallocate should fall back to the method
3088  * of writing zeroes to the required new blocks (the same behavior which is
3089  * expected for file systems which do not support fallocate() system call).
3090  */
3091 long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
3092 {
3093         handle_t *handle;
3094         ext4_lblk_t block;
3095         loff_t new_size;
3096         unsigned int max_blocks;
3097         int ret = 0;
3098         int ret2 = 0;
3099         int retries = 0;
3100         struct buffer_head map_bh;
3101         unsigned int credits, blkbits = inode->i_blkbits;
3102
3103         /*
3104          * currently supporting (pre)allocate mode for extent-based
3105          * files _only_
3106          */
3107         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
3108                 return -EOPNOTSUPP;
3109
3110         /* preallocation to directories is currently not supported */
3111         if (S_ISDIR(inode->i_mode))
3112                 return -ENODEV;
3113
3114         block = offset >> blkbits;
3115         /*
3116          * We can't just convert len to max_blocks because
3117          * If blocksize = 4096 offset = 3072 and len = 2048
3118          */
3119         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3120                                                         - block;
3121         /*
3122          * credits to insert 1 extent into extent tree
3123          */
3124         credits = ext4_chunk_trans_blocks(inode, max_blocks);
3125         mutex_lock(&inode->i_mutex);
3126 retry:
3127         while (ret >= 0 && ret < max_blocks) {
3128                 block = block + ret;
3129                 max_blocks = max_blocks - ret;
3130                 handle = ext4_journal_start(inode, credits);
3131                 if (IS_ERR(handle)) {
3132                         ret = PTR_ERR(handle);
3133                         break;
3134                 }
3135                 map_bh.b_state = 0;
3136                 ret = ext4_get_blocks(handle, inode, block,
3137                                       max_blocks, &map_bh,
3138                                       EXT4_GET_BLOCKS_CREATE_UNINIT_EXT);
3139                 if (ret <= 0) {
3140 #ifdef EXT4FS_DEBUG
3141                         WARN_ON(ret <= 0);
3142                         printk(KERN_ERR "%s: ext4_ext_get_blocks "
3143                                     "returned error inode#%lu, block=%u, "
3144                                     "max_blocks=%u", __func__,
3145                                     inode->i_ino, block, max_blocks);
3146 #endif
3147                         ext4_mark_inode_dirty(handle, inode);
3148                         ret2 = ext4_journal_stop(handle);
3149                         break;
3150                 }
3151                 if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
3152                                                 blkbits) >> blkbits))
3153                         new_size = offset + len;
3154                 else
3155                         new_size = (block + ret) << blkbits;
3156
3157                 ext4_falloc_update_inode(inode, mode, new_size,
3158                                                 buffer_new(&map_bh));
3159                 ext4_mark_inode_dirty(handle, inode);
3160                 ret2 = ext4_journal_stop(handle);
3161                 if (ret2)
3162                         break;
3163         }
3164         if (ret == -ENOSPC &&
3165                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
3166                 ret = 0;
3167                 goto retry;
3168         }
3169         mutex_unlock(&inode->i_mutex);
3170         return ret > 0 ? ret2 : ret;
3171 }
3172
3173 /*
3174  * Callback function called for each extent to gather FIEMAP information.
3175  */
3176 static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path,
3177                        struct ext4_ext_cache *newex, struct ext4_extent *ex,
3178                        void *data)
3179 {
3180         struct fiemap_extent_info *fieinfo = data;
3181         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
3182         __u64   logical;
3183         __u64   physical;
3184         __u64   length;
3185         __u32   flags = 0;
3186         int     error;
3187
3188         logical =  (__u64)newex->ec_block << blksize_bits;
3189
3190         if (newex->ec_type == EXT4_EXT_CACHE_GAP) {
3191                 pgoff_t offset;
3192                 struct page *page;
3193                 struct buffer_head *bh = NULL;
3194
3195                 offset = logical >> PAGE_SHIFT;
3196                 page = find_get_page(inode->i_mapping, offset);
3197                 if (!page || !page_has_buffers(page))
3198                         return EXT_CONTINUE;
3199
3200                 bh = page_buffers(page);
3201
3202                 if (!bh)
3203                         return EXT_CONTINUE;
3204
3205                 if (buffer_delay(bh)) {
3206                         flags |= FIEMAP_EXTENT_DELALLOC;
3207                         page_cache_release(page);
3208                 } else {
3209                         page_cache_release(page);
3210                         return EXT_CONTINUE;
3211                 }
3212         }
3213
3214         physical = (__u64)newex->ec_start << blksize_bits;
3215         length =   (__u64)newex->ec_len << blksize_bits;
3216
3217         if (ex && ext4_ext_is_uninitialized(ex))
3218                 flags |= FIEMAP_EXTENT_UNWRITTEN;
3219
3220         /*
3221          * If this extent reaches EXT_MAX_BLOCK, it must be last.
3222          *
3223          * Or if ext4_ext_next_allocated_block is EXT_MAX_BLOCK,
3224          * this also indicates no more allocated blocks.
3225          *
3226          * XXX this might miss a single-block extent at EXT_MAX_BLOCK
3227          */
3228         if (ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK ||
3229             newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK) {
3230                 loff_t size = i_size_read(inode);
3231                 loff_t bs = EXT4_BLOCK_SIZE(inode->i_sb);
3232
3233                 flags |= FIEMAP_EXTENT_LAST;
3234                 if ((flags & FIEMAP_EXTENT_DELALLOC) &&
3235                     logical+length > size)
3236                         length = (size - logical + bs - 1) & ~(bs-1);
3237         }
3238
3239         error = fiemap_fill_next_extent(fieinfo, logical, physical,
3240                                         length, flags);
3241         if (error < 0)
3242                 return error;
3243         if (error == 1)
3244                 return EXT_BREAK;
3245
3246         return EXT_CONTINUE;
3247 }
3248
3249 /* fiemap flags we can handle specified here */
3250 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
3251
3252 static int ext4_xattr_fiemap(struct inode *inode,
3253                                 struct fiemap_extent_info *fieinfo)
3254 {
3255         __u64 physical = 0;
3256         __u64 length;
3257         __u32 flags = FIEMAP_EXTENT_LAST;
3258         int blockbits = inode->i_sb->s_blocksize_bits;
3259         int error = 0;
3260
3261         /* in-inode? */
3262         if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
3263                 struct ext4_iloc iloc;
3264                 int offset;     /* offset of xattr in inode */
3265
3266                 error = ext4_get_inode_loc(inode, &iloc);
3267                 if (error)
3268                         return error;
3269                 physical = iloc.bh->b_blocknr << blockbits;
3270                 offset = EXT4_GOOD_OLD_INODE_SIZE +
3271                                 EXT4_I(inode)->i_extra_isize;
3272                 physical += offset;
3273                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
3274                 flags |= FIEMAP_EXTENT_DATA_INLINE;
3275         } else { /* external block */
3276                 physical = EXT4_I(inode)->i_file_acl << blockbits;
3277                 length = inode->i_sb->s_blocksize;
3278         }
3279
3280         if (physical)
3281                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
3282                                                 length, flags);
3283         return (error < 0 ? error : 0);
3284 }
3285
3286 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
3287                 __u64 start, __u64 len)
3288 {
3289         ext4_lblk_t start_blk;
3290         ext4_lblk_t len_blks;
3291         int error = 0;
3292
3293         /* fallback to generic here if not in extents fmt */
3294         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
3295                 return generic_block_fiemap(inode, fieinfo, start, len,
3296                         ext4_get_block);
3297
3298         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
3299                 return -EBADR;
3300
3301         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
3302                 error = ext4_xattr_fiemap(inode, fieinfo);
3303         } else {
3304                 start_blk = start >> inode->i_sb->s_blocksize_bits;
3305                 len_blks = len >> inode->i_sb->s_blocksize_bits;
3306
3307                 /*
3308                  * Walk the extent tree gathering extent information.
3309                  * ext4_ext_fiemap_cb will push extents back to user.
3310                  */
3311                 down_read(&EXT4_I(inode)->i_data_sem);
3312                 error = ext4_ext_walk_space(inode, start_blk, len_blks,
3313                                           ext4_ext_fiemap_cb, fieinfo);
3314                 up_read(&EXT4_I(inode)->i_data_sem);
3315         }
3316
3317         return error;
3318 }
3319