3d8c5f50ba33c1c911b70a4250721692b1b13891
[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 #include <trace/events/ext4.h>
48
49 static int ext4_split_extent(handle_t *handle,
50                                 struct inode *inode,
51                                 struct ext4_ext_path *path,
52                                 struct ext4_map_blocks *map,
53                                 int split_flag,
54                                 int flags);
55
56 static int ext4_ext_truncate_extend_restart(handle_t *handle,
57                                             struct inode *inode,
58                                             int needed)
59 {
60         int err;
61
62         if (!ext4_handle_valid(handle))
63                 return 0;
64         if (handle->h_buffer_credits > needed)
65                 return 0;
66         err = ext4_journal_extend(handle, needed);
67         if (err <= 0)
68                 return err;
69         err = ext4_truncate_restart_trans(handle, inode, needed);
70         if (err == 0)
71                 err = -EAGAIN;
72
73         return err;
74 }
75
76 /*
77  * could return:
78  *  - EROFS
79  *  - ENOMEM
80  */
81 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
82                                 struct ext4_ext_path *path)
83 {
84         if (path->p_bh) {
85                 /* path points to block */
86                 return ext4_journal_get_write_access(handle, path->p_bh);
87         }
88         /* path points to leaf/index in inode body */
89         /* we use in-core data, no need to protect them */
90         return 0;
91 }
92
93 /*
94  * could return:
95  *  - EROFS
96  *  - ENOMEM
97  *  - EIO
98  */
99 static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
100                                 struct ext4_ext_path *path)
101 {
102         int err;
103         if (path->p_bh) {
104                 /* path points to block */
105                 err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
106         } else {
107                 /* path points to leaf/index in inode body */
108                 err = ext4_mark_inode_dirty(handle, inode);
109         }
110         return err;
111 }
112
113 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
114                               struct ext4_ext_path *path,
115                               ext4_lblk_t block)
116 {
117         int depth;
118
119         if (path) {
120                 struct ext4_extent *ex;
121                 depth = path->p_depth;
122
123                 /*
124                  * Try to predict block placement assuming that we are
125                  * filling in a file which will eventually be
126                  * non-sparse --- i.e., in the case of libbfd writing
127                  * an ELF object sections out-of-order but in a way
128                  * the eventually results in a contiguous object or
129                  * executable file, or some database extending a table
130                  * space file.  However, this is actually somewhat
131                  * non-ideal if we are writing a sparse file such as
132                  * qemu or KVM writing a raw image file that is going
133                  * to stay fairly sparse, since it will end up
134                  * fragmenting the file system's free space.  Maybe we
135                  * should have some hueristics or some way to allow
136                  * userspace to pass a hint to file system,
137                  * especially if the latter case turns out to be
138                  * common.
139                  */
140                 ex = path[depth].p_ext;
141                 if (ex) {
142                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
143                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
144
145                         if (block > ext_block)
146                                 return ext_pblk + (block - ext_block);
147                         else
148                                 return ext_pblk - (ext_block - block);
149                 }
150
151                 /* it looks like index is empty;
152                  * try to find starting block from index itself */
153                 if (path[depth].p_bh)
154                         return path[depth].p_bh->b_blocknr;
155         }
156
157         /* OK. use inode's group */
158         return ext4_inode_to_goal_block(inode);
159 }
160
161 /*
162  * Allocation for a meta data block
163  */
164 static ext4_fsblk_t
165 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
166                         struct ext4_ext_path *path,
167                         struct ext4_extent *ex, int *err, unsigned int flags)
168 {
169         ext4_fsblk_t goal, newblock;
170
171         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
172         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
173                                         NULL, err);
174         return newblock;
175 }
176
177 static inline int ext4_ext_space_block(struct inode *inode, int check)
178 {
179         int size;
180
181         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
182                         / sizeof(struct ext4_extent);
183         if (!check) {
184 #ifdef AGGRESSIVE_TEST
185                 if (size > 6)
186                         size = 6;
187 #endif
188         }
189         return size;
190 }
191
192 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
193 {
194         int size;
195
196         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
197                         / sizeof(struct ext4_extent_idx);
198         if (!check) {
199 #ifdef AGGRESSIVE_TEST
200                 if (size > 5)
201                         size = 5;
202 #endif
203         }
204         return size;
205 }
206
207 static inline int ext4_ext_space_root(struct inode *inode, int check)
208 {
209         int size;
210
211         size = sizeof(EXT4_I(inode)->i_data);
212         size -= sizeof(struct ext4_extent_header);
213         size /= sizeof(struct ext4_extent);
214         if (!check) {
215 #ifdef AGGRESSIVE_TEST
216                 if (size > 3)
217                         size = 3;
218 #endif
219         }
220         return size;
221 }
222
223 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
224 {
225         int size;
226
227         size = sizeof(EXT4_I(inode)->i_data);
228         size -= sizeof(struct ext4_extent_header);
229         size /= sizeof(struct ext4_extent_idx);
230         if (!check) {
231 #ifdef AGGRESSIVE_TEST
232                 if (size > 4)
233                         size = 4;
234 #endif
235         }
236         return size;
237 }
238
239 /*
240  * Calculate the number of metadata blocks needed
241  * to allocate @blocks
242  * Worse case is one block per extent
243  */
244 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
245 {
246         struct ext4_inode_info *ei = EXT4_I(inode);
247         int idxs, num = 0;
248
249         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
250                 / sizeof(struct ext4_extent_idx));
251
252         /*
253          * If the new delayed allocation block is contiguous with the
254          * previous da block, it can share index blocks with the
255          * previous block, so we only need to allocate a new index
256          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
257          * an additional index block, and at ldxs**3 blocks, yet
258          * another index blocks.
259          */
260         if (ei->i_da_metadata_calc_len &&
261             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
262                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
263                         num++;
264                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
265                         num++;
266                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
267                         num++;
268                         ei->i_da_metadata_calc_len = 0;
269                 } else
270                         ei->i_da_metadata_calc_len++;
271                 ei->i_da_metadata_calc_last_lblock++;
272                 return num;
273         }
274
275         /*
276          * In the worst case we need a new set of index blocks at
277          * every level of the inode's extent tree.
278          */
279         ei->i_da_metadata_calc_len = 1;
280         ei->i_da_metadata_calc_last_lblock = lblock;
281         return ext_depth(inode) + 1;
282 }
283
284 static int
285 ext4_ext_max_entries(struct inode *inode, int depth)
286 {
287         int max;
288
289         if (depth == ext_depth(inode)) {
290                 if (depth == 0)
291                         max = ext4_ext_space_root(inode, 1);
292                 else
293                         max = ext4_ext_space_root_idx(inode, 1);
294         } else {
295                 if (depth == 0)
296                         max = ext4_ext_space_block(inode, 1);
297                 else
298                         max = ext4_ext_space_block_idx(inode, 1);
299         }
300
301         return max;
302 }
303
304 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
305 {
306         ext4_fsblk_t block = ext4_ext_pblock(ext);
307         int len = ext4_ext_get_actual_len(ext);
308
309         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
310 }
311
312 static int ext4_valid_extent_idx(struct inode *inode,
313                                 struct ext4_extent_idx *ext_idx)
314 {
315         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
316
317         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
318 }
319
320 static int ext4_valid_extent_entries(struct inode *inode,
321                                 struct ext4_extent_header *eh,
322                                 int depth)
323 {
324         struct ext4_extent *ext;
325         struct ext4_extent_idx *ext_idx;
326         unsigned short entries;
327         if (eh->eh_entries == 0)
328                 return 1;
329
330         entries = le16_to_cpu(eh->eh_entries);
331
332         if (depth == 0) {
333                 /* leaf entries */
334                 ext = EXT_FIRST_EXTENT(eh);
335                 while (entries) {
336                         if (!ext4_valid_extent(inode, ext))
337                                 return 0;
338                         ext++;
339                         entries--;
340                 }
341         } else {
342                 ext_idx = EXT_FIRST_INDEX(eh);
343                 while (entries) {
344                         if (!ext4_valid_extent_idx(inode, ext_idx))
345                                 return 0;
346                         ext_idx++;
347                         entries--;
348                 }
349         }
350         return 1;
351 }
352
353 static int __ext4_ext_check(const char *function, unsigned int line,
354                             struct inode *inode, struct ext4_extent_header *eh,
355                             int depth)
356 {
357         const char *error_msg;
358         int max = 0;
359
360         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
361                 error_msg = "invalid magic";
362                 goto corrupted;
363         }
364         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
365                 error_msg = "unexpected eh_depth";
366                 goto corrupted;
367         }
368         if (unlikely(eh->eh_max == 0)) {
369                 error_msg = "invalid eh_max";
370                 goto corrupted;
371         }
372         max = ext4_ext_max_entries(inode, depth);
373         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
374                 error_msg = "too large eh_max";
375                 goto corrupted;
376         }
377         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
378                 error_msg = "invalid eh_entries";
379                 goto corrupted;
380         }
381         if (!ext4_valid_extent_entries(inode, eh, depth)) {
382                 error_msg = "invalid extent entries";
383                 goto corrupted;
384         }
385         return 0;
386
387 corrupted:
388         ext4_error_inode(inode, function, line, 0,
389                         "bad header/extent: %s - magic %x, "
390                         "entries %u, max %u(%u), depth %u(%u)",
391                         error_msg, le16_to_cpu(eh->eh_magic),
392                         le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
393                         max, le16_to_cpu(eh->eh_depth), depth);
394
395         return -EIO;
396 }
397
398 #define ext4_ext_check(inode, eh, depth)        \
399         __ext4_ext_check(__func__, __LINE__, inode, eh, depth)
400
401 int ext4_ext_check_inode(struct inode *inode)
402 {
403         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
404 }
405
406 #ifdef EXT_DEBUG
407 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
408 {
409         int k, l = path->p_depth;
410
411         ext_debug("path:");
412         for (k = 0; k <= l; k++, path++) {
413                 if (path->p_idx) {
414                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
415                             ext4_idx_pblock(path->p_idx));
416                 } else if (path->p_ext) {
417                         ext_debug("  %d:[%d]%d:%llu ",
418                                   le32_to_cpu(path->p_ext->ee_block),
419                                   ext4_ext_is_uninitialized(path->p_ext),
420                                   ext4_ext_get_actual_len(path->p_ext),
421                                   ext4_ext_pblock(path->p_ext));
422                 } else
423                         ext_debug("  []");
424         }
425         ext_debug("\n");
426 }
427
428 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
429 {
430         int depth = ext_depth(inode);
431         struct ext4_extent_header *eh;
432         struct ext4_extent *ex;
433         int i;
434
435         if (!path)
436                 return;
437
438         eh = path[depth].p_hdr;
439         ex = EXT_FIRST_EXTENT(eh);
440
441         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
442
443         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
444                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
445                           ext4_ext_is_uninitialized(ex),
446                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
447         }
448         ext_debug("\n");
449 }
450
451 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
452                         ext4_fsblk_t newblock, int level)
453 {
454         int depth = ext_depth(inode);
455         struct ext4_extent *ex;
456
457         if (depth != level) {
458                 struct ext4_extent_idx *idx;
459                 idx = path[level].p_idx;
460                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
461                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
462                                         le32_to_cpu(idx->ei_block),
463                                         ext4_idx_pblock(idx),
464                                         newblock);
465                         idx++;
466                 }
467
468                 return;
469         }
470
471         ex = path[depth].p_ext;
472         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
473                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
474                                 le32_to_cpu(ex->ee_block),
475                                 ext4_ext_pblock(ex),
476                                 ext4_ext_is_uninitialized(ex),
477                                 ext4_ext_get_actual_len(ex),
478                                 newblock);
479                 ex++;
480         }
481 }
482
483 #else
484 #define ext4_ext_show_path(inode, path)
485 #define ext4_ext_show_leaf(inode, path)
486 #define ext4_ext_show_move(inode, path, newblock, level)
487 #endif
488
489 void ext4_ext_drop_refs(struct ext4_ext_path *path)
490 {
491         int depth = path->p_depth;
492         int i;
493
494         for (i = 0; i <= depth; i++, path++)
495                 if (path->p_bh) {
496                         brelse(path->p_bh);
497                         path->p_bh = NULL;
498                 }
499 }
500
501 /*
502  * ext4_ext_binsearch_idx:
503  * binary search for the closest index of the given block
504  * the header must be checked before calling this
505  */
506 static void
507 ext4_ext_binsearch_idx(struct inode *inode,
508                         struct ext4_ext_path *path, ext4_lblk_t block)
509 {
510         struct ext4_extent_header *eh = path->p_hdr;
511         struct ext4_extent_idx *r, *l, *m;
512
513
514         ext_debug("binsearch for %u(idx):  ", block);
515
516         l = EXT_FIRST_INDEX(eh) + 1;
517         r = EXT_LAST_INDEX(eh);
518         while (l <= r) {
519                 m = l + (r - l) / 2;
520                 if (block < le32_to_cpu(m->ei_block))
521                         r = m - 1;
522                 else
523                         l = m + 1;
524                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
525                                 m, le32_to_cpu(m->ei_block),
526                                 r, le32_to_cpu(r->ei_block));
527         }
528
529         path->p_idx = l - 1;
530         ext_debug("  -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
531                   ext4_idx_pblock(path->p_idx));
532
533 #ifdef CHECK_BINSEARCH
534         {
535                 struct ext4_extent_idx *chix, *ix;
536                 int k;
537
538                 chix = ix = EXT_FIRST_INDEX(eh);
539                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
540                   if (k != 0 &&
541                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
542                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
543                                        "first=0x%p\n", k,
544                                        ix, EXT_FIRST_INDEX(eh));
545                                 printk(KERN_DEBUG "%u <= %u\n",
546                                        le32_to_cpu(ix->ei_block),
547                                        le32_to_cpu(ix[-1].ei_block));
548                         }
549                         BUG_ON(k && le32_to_cpu(ix->ei_block)
550                                            <= le32_to_cpu(ix[-1].ei_block));
551                         if (block < le32_to_cpu(ix->ei_block))
552                                 break;
553                         chix = ix;
554                 }
555                 BUG_ON(chix != path->p_idx);
556         }
557 #endif
558
559 }
560
561 /*
562  * ext4_ext_binsearch:
563  * binary search for closest extent of the given block
564  * the header must be checked before calling this
565  */
566 static void
567 ext4_ext_binsearch(struct inode *inode,
568                 struct ext4_ext_path *path, ext4_lblk_t block)
569 {
570         struct ext4_extent_header *eh = path->p_hdr;
571         struct ext4_extent *r, *l, *m;
572
573         if (eh->eh_entries == 0) {
574                 /*
575                  * this leaf is empty:
576                  * we get such a leaf in split/add case
577                  */
578                 return;
579         }
580
581         ext_debug("binsearch for %u:  ", block);
582
583         l = EXT_FIRST_EXTENT(eh) + 1;
584         r = EXT_LAST_EXTENT(eh);
585
586         while (l <= r) {
587                 m = l + (r - l) / 2;
588                 if (block < le32_to_cpu(m->ee_block))
589                         r = m - 1;
590                 else
591                         l = m + 1;
592                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
593                                 m, le32_to_cpu(m->ee_block),
594                                 r, le32_to_cpu(r->ee_block));
595         }
596
597         path->p_ext = l - 1;
598         ext_debug("  -> %d:%llu:[%d]%d ",
599                         le32_to_cpu(path->p_ext->ee_block),
600                         ext4_ext_pblock(path->p_ext),
601                         ext4_ext_is_uninitialized(path->p_ext),
602                         ext4_ext_get_actual_len(path->p_ext));
603
604 #ifdef CHECK_BINSEARCH
605         {
606                 struct ext4_extent *chex, *ex;
607                 int k;
608
609                 chex = ex = EXT_FIRST_EXTENT(eh);
610                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
611                         BUG_ON(k && le32_to_cpu(ex->ee_block)
612                                           <= le32_to_cpu(ex[-1].ee_block));
613                         if (block < le32_to_cpu(ex->ee_block))
614                                 break;
615                         chex = ex;
616                 }
617                 BUG_ON(chex != path->p_ext);
618         }
619 #endif
620
621 }
622
623 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
624 {
625         struct ext4_extent_header *eh;
626
627         eh = ext_inode_hdr(inode);
628         eh->eh_depth = 0;
629         eh->eh_entries = 0;
630         eh->eh_magic = EXT4_EXT_MAGIC;
631         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
632         ext4_mark_inode_dirty(handle, inode);
633         ext4_ext_invalidate_cache(inode);
634         return 0;
635 }
636
637 struct ext4_ext_path *
638 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
639                                         struct ext4_ext_path *path)
640 {
641         struct ext4_extent_header *eh;
642         struct buffer_head *bh;
643         short int depth, i, ppos = 0, alloc = 0;
644
645         eh = ext_inode_hdr(inode);
646         depth = ext_depth(inode);
647
648         /* account possible depth increase */
649         if (!path) {
650                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
651                                 GFP_NOFS);
652                 if (!path)
653                         return ERR_PTR(-ENOMEM);
654                 alloc = 1;
655         }
656         path[0].p_hdr = eh;
657         path[0].p_bh = NULL;
658
659         i = depth;
660         /* walk through the tree */
661         while (i) {
662                 int need_to_validate = 0;
663
664                 ext_debug("depth %d: num %d, max %d\n",
665                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
666
667                 ext4_ext_binsearch_idx(inode, path + ppos, block);
668                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
669                 path[ppos].p_depth = i;
670                 path[ppos].p_ext = NULL;
671
672                 bh = sb_getblk(inode->i_sb, path[ppos].p_block);
673                 if (unlikely(!bh))
674                         goto err;
675                 if (!bh_uptodate_or_lock(bh)) {
676                         trace_ext4_ext_load_extent(inode, block,
677                                                 path[ppos].p_block);
678                         if (bh_submit_read(bh) < 0) {
679                                 put_bh(bh);
680                                 goto err;
681                         }
682                         /* validate the extent entries */
683                         need_to_validate = 1;
684                 }
685                 eh = ext_block_hdr(bh);
686                 ppos++;
687                 if (unlikely(ppos > depth)) {
688                         put_bh(bh);
689                         EXT4_ERROR_INODE(inode,
690                                          "ppos %d > depth %d", ppos, depth);
691                         goto err;
692                 }
693                 path[ppos].p_bh = bh;
694                 path[ppos].p_hdr = eh;
695                 i--;
696
697                 if (need_to_validate && ext4_ext_check(inode, eh, i))
698                         goto err;
699         }
700
701         path[ppos].p_depth = i;
702         path[ppos].p_ext = NULL;
703         path[ppos].p_idx = NULL;
704
705         /* find extent */
706         ext4_ext_binsearch(inode, path + ppos, block);
707         /* if not an empty leaf */
708         if (path[ppos].p_ext)
709                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
710
711         ext4_ext_show_path(inode, path);
712
713         return path;
714
715 err:
716         ext4_ext_drop_refs(path);
717         if (alloc)
718                 kfree(path);
719         return ERR_PTR(-EIO);
720 }
721
722 /*
723  * ext4_ext_insert_index:
724  * insert new index [@logical;@ptr] into the block at @curp;
725  * check where to insert: before @curp or after @curp
726  */
727 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
728                                  struct ext4_ext_path *curp,
729                                  int logical, ext4_fsblk_t ptr)
730 {
731         struct ext4_extent_idx *ix;
732         int len, err;
733
734         err = ext4_ext_get_access(handle, inode, curp);
735         if (err)
736                 return err;
737
738         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
739                 EXT4_ERROR_INODE(inode,
740                                  "logical %d == ei_block %d!",
741                                  logical, le32_to_cpu(curp->p_idx->ei_block));
742                 return -EIO;
743         }
744         len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
745         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
746                 /* insert after */
747                 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
748                         len = (len - 1) * sizeof(struct ext4_extent_idx);
749                         len = len < 0 ? 0 : len;
750                         ext_debug("insert new index %d after: %llu. "
751                                         "move %d from 0x%p to 0x%p\n",
752                                         logical, ptr, len,
753                                         (curp->p_idx + 1), (curp->p_idx + 2));
754                         memmove(curp->p_idx + 2, curp->p_idx + 1, len);
755                 }
756                 ix = curp->p_idx + 1;
757         } else {
758                 /* insert before */
759                 len = len * sizeof(struct ext4_extent_idx);
760                 len = len < 0 ? 0 : len;
761                 ext_debug("insert new index %d before: %llu. "
762                                 "move %d from 0x%p to 0x%p\n",
763                                 logical, ptr, len,
764                                 curp->p_idx, (curp->p_idx + 1));
765                 memmove(curp->p_idx + 1, curp->p_idx, len);
766                 ix = curp->p_idx;
767         }
768
769         ix->ei_block = cpu_to_le32(logical);
770         ext4_idx_store_pblock(ix, ptr);
771         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
772
773         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
774                              > le16_to_cpu(curp->p_hdr->eh_max))) {
775                 EXT4_ERROR_INODE(inode,
776                                  "eh_entries %d > eh_max %d!",
777                                  le16_to_cpu(curp->p_hdr->eh_entries),
778                                  le16_to_cpu(curp->p_hdr->eh_max));
779                 return -EIO;
780         }
781         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
782                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
783                 return -EIO;
784         }
785
786         err = ext4_ext_dirty(handle, inode, curp);
787         ext4_std_error(inode->i_sb, err);
788
789         return err;
790 }
791
792 /*
793  * ext4_ext_split:
794  * inserts new subtree into the path, using free index entry
795  * at depth @at:
796  * - allocates all needed blocks (new leaf and all intermediate index blocks)
797  * - makes decision where to split
798  * - moves remaining extents and index entries (right to the split point)
799  *   into the newly allocated blocks
800  * - initializes subtree
801  */
802 static int ext4_ext_split(handle_t *handle, struct inode *inode,
803                           unsigned int flags,
804                           struct ext4_ext_path *path,
805                           struct ext4_extent *newext, int at)
806 {
807         struct buffer_head *bh = NULL;
808         int depth = ext_depth(inode);
809         struct ext4_extent_header *neh;
810         struct ext4_extent_idx *fidx;
811         int i = at, k, m, a;
812         ext4_fsblk_t newblock, oldblock;
813         __le32 border;
814         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
815         int err = 0;
816
817         /* make decision: where to split? */
818         /* FIXME: now decision is simplest: at current extent */
819
820         /* if current leaf will be split, then we should use
821          * border from split point */
822         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
823                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
824                 return -EIO;
825         }
826         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
827                 border = path[depth].p_ext[1].ee_block;
828                 ext_debug("leaf will be split."
829                                 " next leaf starts at %d\n",
830                                   le32_to_cpu(border));
831         } else {
832                 border = newext->ee_block;
833                 ext_debug("leaf will be added."
834                                 " next leaf starts at %d\n",
835                                 le32_to_cpu(border));
836         }
837
838         /*
839          * If error occurs, then we break processing
840          * and mark filesystem read-only. index won't
841          * be inserted and tree will be in consistent
842          * state. Next mount will repair buffers too.
843          */
844
845         /*
846          * Get array to track all allocated blocks.
847          * We need this to handle errors and free blocks
848          * upon them.
849          */
850         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
851         if (!ablocks)
852                 return -ENOMEM;
853
854         /* allocate all needed blocks */
855         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
856         for (a = 0; a < depth - at; a++) {
857                 newblock = ext4_ext_new_meta_block(handle, inode, path,
858                                                    newext, &err, flags);
859                 if (newblock == 0)
860                         goto cleanup;
861                 ablocks[a] = newblock;
862         }
863
864         /* initialize new leaf */
865         newblock = ablocks[--a];
866         if (unlikely(newblock == 0)) {
867                 EXT4_ERROR_INODE(inode, "newblock == 0!");
868                 err = -EIO;
869                 goto cleanup;
870         }
871         bh = sb_getblk(inode->i_sb, newblock);
872         if (!bh) {
873                 err = -EIO;
874                 goto cleanup;
875         }
876         lock_buffer(bh);
877
878         err = ext4_journal_get_create_access(handle, bh);
879         if (err)
880                 goto cleanup;
881
882         neh = ext_block_hdr(bh);
883         neh->eh_entries = 0;
884         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
885         neh->eh_magic = EXT4_EXT_MAGIC;
886         neh->eh_depth = 0;
887
888         /* move remainder of path[depth] to the new leaf */
889         if (unlikely(path[depth].p_hdr->eh_entries !=
890                      path[depth].p_hdr->eh_max)) {
891                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
892                                  path[depth].p_hdr->eh_entries,
893                                  path[depth].p_hdr->eh_max);
894                 err = -EIO;
895                 goto cleanup;
896         }
897         /* start copy from next extent */
898         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
899         ext4_ext_show_move(inode, path, newblock, depth);
900         if (m) {
901                 struct ext4_extent *ex;
902                 ex = EXT_FIRST_EXTENT(neh);
903                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
904                 le16_add_cpu(&neh->eh_entries, m);
905         }
906
907         set_buffer_uptodate(bh);
908         unlock_buffer(bh);
909
910         err = ext4_handle_dirty_metadata(handle, inode, bh);
911         if (err)
912                 goto cleanup;
913         brelse(bh);
914         bh = NULL;
915
916         /* correct old leaf */
917         if (m) {
918                 err = ext4_ext_get_access(handle, inode, path + depth);
919                 if (err)
920                         goto cleanup;
921                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
922                 err = ext4_ext_dirty(handle, inode, path + depth);
923                 if (err)
924                         goto cleanup;
925
926         }
927
928         /* create intermediate indexes */
929         k = depth - at - 1;
930         if (unlikely(k < 0)) {
931                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
932                 err = -EIO;
933                 goto cleanup;
934         }
935         if (k)
936                 ext_debug("create %d intermediate indices\n", k);
937         /* insert new index into current index block */
938         /* current depth stored in i var */
939         i = depth - 1;
940         while (k--) {
941                 oldblock = newblock;
942                 newblock = ablocks[--a];
943                 bh = sb_getblk(inode->i_sb, newblock);
944                 if (!bh) {
945                         err = -EIO;
946                         goto cleanup;
947                 }
948                 lock_buffer(bh);
949
950                 err = ext4_journal_get_create_access(handle, bh);
951                 if (err)
952                         goto cleanup;
953
954                 neh = ext_block_hdr(bh);
955                 neh->eh_entries = cpu_to_le16(1);
956                 neh->eh_magic = EXT4_EXT_MAGIC;
957                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
958                 neh->eh_depth = cpu_to_le16(depth - i);
959                 fidx = EXT_FIRST_INDEX(neh);
960                 fidx->ei_block = border;
961                 ext4_idx_store_pblock(fidx, oldblock);
962
963                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
964                                 i, newblock, le32_to_cpu(border), oldblock);
965
966                 /* move remainder of path[i] to the new index block */
967                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
968                                         EXT_LAST_INDEX(path[i].p_hdr))) {
969                         EXT4_ERROR_INODE(inode,
970                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
971                                          le32_to_cpu(path[i].p_ext->ee_block));
972                         err = -EIO;
973                         goto cleanup;
974                 }
975                 /* start copy indexes */
976                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
977                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
978                                 EXT_MAX_INDEX(path[i].p_hdr));
979                 ext4_ext_show_move(inode, path, newblock, i);
980                 if (m) {
981                         memmove(++fidx, path[i].p_idx,
982                                 sizeof(struct ext4_extent_idx) * m);
983                         le16_add_cpu(&neh->eh_entries, m);
984                 }
985                 set_buffer_uptodate(bh);
986                 unlock_buffer(bh);
987
988                 err = ext4_handle_dirty_metadata(handle, inode, bh);
989                 if (err)
990                         goto cleanup;
991                 brelse(bh);
992                 bh = NULL;
993
994                 /* correct old index */
995                 if (m) {
996                         err = ext4_ext_get_access(handle, inode, path + i);
997                         if (err)
998                                 goto cleanup;
999                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1000                         err = ext4_ext_dirty(handle, inode, path + i);
1001                         if (err)
1002                                 goto cleanup;
1003                 }
1004
1005                 i--;
1006         }
1007
1008         /* insert new index */
1009         err = ext4_ext_insert_index(handle, inode, path + at,
1010                                     le32_to_cpu(border), newblock);
1011
1012 cleanup:
1013         if (bh) {
1014                 if (buffer_locked(bh))
1015                         unlock_buffer(bh);
1016                 brelse(bh);
1017         }
1018
1019         if (err) {
1020                 /* free all allocated blocks in error case */
1021                 for (i = 0; i < depth; i++) {
1022                         if (!ablocks[i])
1023                                 continue;
1024                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1025                                          EXT4_FREE_BLOCKS_METADATA);
1026                 }
1027         }
1028         kfree(ablocks);
1029
1030         return err;
1031 }
1032
1033 /*
1034  * ext4_ext_grow_indepth:
1035  * implements tree growing procedure:
1036  * - allocates new block
1037  * - moves top-level data (index block or leaf) into the new block
1038  * - initializes new top-level, creating index that points to the
1039  *   just created block
1040  */
1041 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1042                                  unsigned int flags,
1043                                  struct ext4_ext_path *path,
1044                                  struct ext4_extent *newext)
1045 {
1046         struct ext4_ext_path *curp = path;
1047         struct ext4_extent_header *neh;
1048         struct buffer_head *bh;
1049         ext4_fsblk_t newblock;
1050         int err = 0;
1051
1052         newblock = ext4_ext_new_meta_block(handle, inode, path,
1053                 newext, &err, flags);
1054         if (newblock == 0)
1055                 return err;
1056
1057         bh = sb_getblk(inode->i_sb, newblock);
1058         if (!bh) {
1059                 err = -EIO;
1060                 ext4_std_error(inode->i_sb, err);
1061                 return err;
1062         }
1063         lock_buffer(bh);
1064
1065         err = ext4_journal_get_create_access(handle, bh);
1066         if (err) {
1067                 unlock_buffer(bh);
1068                 goto out;
1069         }
1070
1071         /* move top-level index/leaf into new block */
1072         memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
1073
1074         /* set size of new block */
1075         neh = ext_block_hdr(bh);
1076         /* old root could have indexes or leaves
1077          * so calculate e_max right way */
1078         if (ext_depth(inode))
1079                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1080         else
1081                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1082         neh->eh_magic = EXT4_EXT_MAGIC;
1083         set_buffer_uptodate(bh);
1084         unlock_buffer(bh);
1085
1086         err = ext4_handle_dirty_metadata(handle, inode, bh);
1087         if (err)
1088                 goto out;
1089
1090         /* create index in new top-level index: num,max,pointer */
1091         err = ext4_ext_get_access(handle, inode, curp);
1092         if (err)
1093                 goto out;
1094
1095         curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
1096         curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1097         curp->p_hdr->eh_entries = cpu_to_le16(1);
1098         curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
1099
1100         if (path[0].p_hdr->eh_depth)
1101                 curp->p_idx->ei_block =
1102                         EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
1103         else
1104                 curp->p_idx->ei_block =
1105                         EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
1106         ext4_idx_store_pblock(curp->p_idx, newblock);
1107
1108         neh = ext_inode_hdr(inode);
1109         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1110                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1111                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1112                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1113
1114         neh->eh_depth = cpu_to_le16(path->p_depth + 1);
1115         err = ext4_ext_dirty(handle, inode, curp);
1116 out:
1117         brelse(bh);
1118
1119         return err;
1120 }
1121
1122 /*
1123  * ext4_ext_create_new_leaf:
1124  * finds empty index and adds new leaf.
1125  * if no free index is found, then it requests in-depth growing.
1126  */
1127 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1128                                     unsigned int flags,
1129                                     struct ext4_ext_path *path,
1130                                     struct ext4_extent *newext)
1131 {
1132         struct ext4_ext_path *curp;
1133         int depth, i, err = 0;
1134
1135 repeat:
1136         i = depth = ext_depth(inode);
1137
1138         /* walk up to the tree and look for free index entry */
1139         curp = path + depth;
1140         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1141                 i--;
1142                 curp--;
1143         }
1144
1145         /* we use already allocated block for index block,
1146          * so subsequent data blocks should be contiguous */
1147         if (EXT_HAS_FREE_INDEX(curp)) {
1148                 /* if we found index with free entry, then use that
1149                  * entry: create all needed subtree and add new leaf */
1150                 err = ext4_ext_split(handle, inode, flags, path, newext, i);
1151                 if (err)
1152                         goto out;
1153
1154                 /* refill path */
1155                 ext4_ext_drop_refs(path);
1156                 path = ext4_ext_find_extent(inode,
1157                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1158                                     path);
1159                 if (IS_ERR(path))
1160                         err = PTR_ERR(path);
1161         } else {
1162                 /* tree is full, time to grow in depth */
1163                 err = ext4_ext_grow_indepth(handle, inode, flags,
1164                                             path, newext);
1165                 if (err)
1166                         goto out;
1167
1168                 /* refill path */
1169                 ext4_ext_drop_refs(path);
1170                 path = ext4_ext_find_extent(inode,
1171                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1172                                     path);
1173                 if (IS_ERR(path)) {
1174                         err = PTR_ERR(path);
1175                         goto out;
1176                 }
1177
1178                 /*
1179                  * only first (depth 0 -> 1) produces free space;
1180                  * in all other cases we have to split the grown tree
1181                  */
1182                 depth = ext_depth(inode);
1183                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1184                         /* now we need to split */
1185                         goto repeat;
1186                 }
1187         }
1188
1189 out:
1190         return err;
1191 }
1192
1193 /*
1194  * search the closest allocated block to the left for *logical
1195  * and returns it at @logical + it's physical address at @phys
1196  * if *logical is the smallest allocated block, the function
1197  * returns 0 at @phys
1198  * return value contains 0 (success) or error code
1199  */
1200 static int ext4_ext_search_left(struct inode *inode,
1201                                 struct ext4_ext_path *path,
1202                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1203 {
1204         struct ext4_extent_idx *ix;
1205         struct ext4_extent *ex;
1206         int depth, ee_len;
1207
1208         if (unlikely(path == NULL)) {
1209                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1210                 return -EIO;
1211         }
1212         depth = path->p_depth;
1213         *phys = 0;
1214
1215         if (depth == 0 && path->p_ext == NULL)
1216                 return 0;
1217
1218         /* usually extent in the path covers blocks smaller
1219          * then *logical, but it can be that extent is the
1220          * first one in the file */
1221
1222         ex = path[depth].p_ext;
1223         ee_len = ext4_ext_get_actual_len(ex);
1224         if (*logical < le32_to_cpu(ex->ee_block)) {
1225                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1226                         EXT4_ERROR_INODE(inode,
1227                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1228                                          *logical, le32_to_cpu(ex->ee_block));
1229                         return -EIO;
1230                 }
1231                 while (--depth >= 0) {
1232                         ix = path[depth].p_idx;
1233                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1234                                 EXT4_ERROR_INODE(inode,
1235                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1236                                   ix != NULL ? ix->ei_block : 0,
1237                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1238                                     EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0,
1239                                   depth);
1240                                 return -EIO;
1241                         }
1242                 }
1243                 return 0;
1244         }
1245
1246         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1247                 EXT4_ERROR_INODE(inode,
1248                                  "logical %d < ee_block %d + ee_len %d!",
1249                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1250                 return -EIO;
1251         }
1252
1253         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1254         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1255         return 0;
1256 }
1257
1258 /*
1259  * search the closest allocated block to the right for *logical
1260  * and returns it at @logical + it's physical address at @phys
1261  * if *logical is the smallest allocated block, the function
1262  * returns 0 at @phys
1263  * return value contains 0 (success) or error code
1264  */
1265 static int ext4_ext_search_right(struct inode *inode,
1266                                  struct ext4_ext_path *path,
1267                                  ext4_lblk_t *logical, ext4_fsblk_t *phys)
1268 {
1269         struct buffer_head *bh = NULL;
1270         struct ext4_extent_header *eh;
1271         struct ext4_extent_idx *ix;
1272         struct ext4_extent *ex;
1273         ext4_fsblk_t block;
1274         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1275         int ee_len;
1276
1277         if (unlikely(path == NULL)) {
1278                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1279                 return -EIO;
1280         }
1281         depth = path->p_depth;
1282         *phys = 0;
1283
1284         if (depth == 0 && path->p_ext == NULL)
1285                 return 0;
1286
1287         /* usually extent in the path covers blocks smaller
1288          * then *logical, but it can be that extent is the
1289          * first one in the file */
1290
1291         ex = path[depth].p_ext;
1292         ee_len = ext4_ext_get_actual_len(ex);
1293         if (*logical < le32_to_cpu(ex->ee_block)) {
1294                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1295                         EXT4_ERROR_INODE(inode,
1296                                          "first_extent(path[%d].p_hdr) != ex",
1297                                          depth);
1298                         return -EIO;
1299                 }
1300                 while (--depth >= 0) {
1301                         ix = path[depth].p_idx;
1302                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1303                                 EXT4_ERROR_INODE(inode,
1304                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1305                                                  *logical);
1306                                 return -EIO;
1307                         }
1308                 }
1309                 *logical = le32_to_cpu(ex->ee_block);
1310                 *phys = ext4_ext_pblock(ex);
1311                 return 0;
1312         }
1313
1314         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1315                 EXT4_ERROR_INODE(inode,
1316                                  "logical %d < ee_block %d + ee_len %d!",
1317                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1318                 return -EIO;
1319         }
1320
1321         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1322                 /* next allocated block in this leaf */
1323                 ex++;
1324                 *logical = le32_to_cpu(ex->ee_block);
1325                 *phys = ext4_ext_pblock(ex);
1326                 return 0;
1327         }
1328
1329         /* go up and search for index to the right */
1330         while (--depth >= 0) {
1331                 ix = path[depth].p_idx;
1332                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1333                         goto got_index;
1334         }
1335
1336         /* we've gone up to the root and found no index to the right */
1337         return 0;
1338
1339 got_index:
1340         /* we've found index to the right, let's
1341          * follow it and find the closest allocated
1342          * block to the right */
1343         ix++;
1344         block = ext4_idx_pblock(ix);
1345         while (++depth < path->p_depth) {
1346                 bh = sb_bread(inode->i_sb, block);
1347                 if (bh == NULL)
1348                         return -EIO;
1349                 eh = ext_block_hdr(bh);
1350                 /* subtract from p_depth to get proper eh_depth */
1351                 if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1352                         put_bh(bh);
1353                         return -EIO;
1354                 }
1355                 ix = EXT_FIRST_INDEX(eh);
1356                 block = ext4_idx_pblock(ix);
1357                 put_bh(bh);
1358         }
1359
1360         bh = sb_bread(inode->i_sb, block);
1361         if (bh == NULL)
1362                 return -EIO;
1363         eh = ext_block_hdr(bh);
1364         if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
1365                 put_bh(bh);
1366                 return -EIO;
1367         }
1368         ex = EXT_FIRST_EXTENT(eh);
1369         *logical = le32_to_cpu(ex->ee_block);
1370         *phys = ext4_ext_pblock(ex);
1371         put_bh(bh);
1372         return 0;
1373 }
1374
1375 /*
1376  * ext4_ext_next_allocated_block:
1377  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1378  * NOTE: it considers block number from index entry as
1379  * allocated block. Thus, index entries have to be consistent
1380  * with leaves.
1381  */
1382 static ext4_lblk_t
1383 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1384 {
1385         int depth;
1386
1387         BUG_ON(path == NULL);
1388         depth = path->p_depth;
1389
1390         if (depth == 0 && path->p_ext == NULL)
1391                 return EXT_MAX_BLOCKS;
1392
1393         while (depth >= 0) {
1394                 if (depth == path->p_depth) {
1395                         /* leaf */
1396                         if (path[depth].p_ext !=
1397                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1398                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1399                 } else {
1400                         /* index */
1401                         if (path[depth].p_idx !=
1402                                         EXT_LAST_INDEX(path[depth].p_hdr))
1403                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1404                 }
1405                 depth--;
1406         }
1407
1408         return EXT_MAX_BLOCKS;
1409 }
1410
1411 /*
1412  * ext4_ext_next_leaf_block:
1413  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1414  */
1415 static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
1416                                         struct ext4_ext_path *path)
1417 {
1418         int depth;
1419
1420         BUG_ON(path == NULL);
1421         depth = path->p_depth;
1422
1423         /* zero-tree has no leaf blocks at all */
1424         if (depth == 0)
1425                 return EXT_MAX_BLOCKS;
1426
1427         /* go to index block */
1428         depth--;
1429
1430         while (depth >= 0) {
1431                 if (path[depth].p_idx !=
1432                                 EXT_LAST_INDEX(path[depth].p_hdr))
1433                         return (ext4_lblk_t)
1434                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1435                 depth--;
1436         }
1437
1438         return EXT_MAX_BLOCKS;
1439 }
1440
1441 /*
1442  * ext4_ext_correct_indexes:
1443  * if leaf gets modified and modified extent is first in the leaf,
1444  * then we have to correct all indexes above.
1445  * TODO: do we need to correct tree in all cases?
1446  */
1447 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1448                                 struct ext4_ext_path *path)
1449 {
1450         struct ext4_extent_header *eh;
1451         int depth = ext_depth(inode);
1452         struct ext4_extent *ex;
1453         __le32 border;
1454         int k, err = 0;
1455
1456         eh = path[depth].p_hdr;
1457         ex = path[depth].p_ext;
1458
1459         if (unlikely(ex == NULL || eh == NULL)) {
1460                 EXT4_ERROR_INODE(inode,
1461                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1462                 return -EIO;
1463         }
1464
1465         if (depth == 0) {
1466                 /* there is no tree at all */
1467                 return 0;
1468         }
1469
1470         if (ex != EXT_FIRST_EXTENT(eh)) {
1471                 /* we correct tree if first leaf got modified only */
1472                 return 0;
1473         }
1474
1475         /*
1476          * TODO: we need correction if border is smaller than current one
1477          */
1478         k = depth - 1;
1479         border = path[depth].p_ext->ee_block;
1480         err = ext4_ext_get_access(handle, inode, path + k);
1481         if (err)
1482                 return err;
1483         path[k].p_idx->ei_block = border;
1484         err = ext4_ext_dirty(handle, inode, path + k);
1485         if (err)
1486                 return err;
1487
1488         while (k--) {
1489                 /* change all left-side indexes */
1490                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1491                         break;
1492                 err = ext4_ext_get_access(handle, inode, path + k);
1493                 if (err)
1494                         break;
1495                 path[k].p_idx->ei_block = border;
1496                 err = ext4_ext_dirty(handle, inode, path + k);
1497                 if (err)
1498                         break;
1499         }
1500
1501         return err;
1502 }
1503
1504 int
1505 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1506                                 struct ext4_extent *ex2)
1507 {
1508         unsigned short ext1_ee_len, ext2_ee_len, max_len;
1509
1510         /*
1511          * Make sure that either both extents are uninitialized, or
1512          * both are _not_.
1513          */
1514         if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1515                 return 0;
1516
1517         if (ext4_ext_is_uninitialized(ex1))
1518                 max_len = EXT_UNINIT_MAX_LEN;
1519         else
1520                 max_len = EXT_INIT_MAX_LEN;
1521
1522         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1523         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1524
1525         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1526                         le32_to_cpu(ex2->ee_block))
1527                 return 0;
1528
1529         /*
1530          * To allow future support for preallocated extents to be added
1531          * as an RO_COMPAT feature, refuse to merge to extents if
1532          * this can result in the top bit of ee_len being set.
1533          */
1534         if (ext1_ee_len + ext2_ee_len > max_len)
1535                 return 0;
1536 #ifdef AGGRESSIVE_TEST
1537         if (ext1_ee_len >= 4)
1538                 return 0;
1539 #endif
1540
1541         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1542                 return 1;
1543         return 0;
1544 }
1545
1546 /*
1547  * This function tries to merge the "ex" extent to the next extent in the tree.
1548  * It always tries to merge towards right. If you want to merge towards
1549  * left, pass "ex - 1" as argument instead of "ex".
1550  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1551  * 1 if they got merged.
1552  */
1553 static int ext4_ext_try_to_merge_right(struct inode *inode,
1554                                  struct ext4_ext_path *path,
1555                                  struct ext4_extent *ex)
1556 {
1557         struct ext4_extent_header *eh;
1558         unsigned int depth, len;
1559         int merge_done = 0;
1560         int uninitialized = 0;
1561
1562         depth = ext_depth(inode);
1563         BUG_ON(path[depth].p_hdr == NULL);
1564         eh = path[depth].p_hdr;
1565
1566         while (ex < EXT_LAST_EXTENT(eh)) {
1567                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1568                         break;
1569                 /* merge with next extent! */
1570                 if (ext4_ext_is_uninitialized(ex))
1571                         uninitialized = 1;
1572                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1573                                 + ext4_ext_get_actual_len(ex + 1));
1574                 if (uninitialized)
1575                         ext4_ext_mark_uninitialized(ex);
1576
1577                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1578                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1579                                 * sizeof(struct ext4_extent);
1580                         memmove(ex + 1, ex + 2, len);
1581                 }
1582                 le16_add_cpu(&eh->eh_entries, -1);
1583                 merge_done = 1;
1584                 WARN_ON(eh->eh_entries == 0);
1585                 if (!eh->eh_entries)
1586                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1587         }
1588
1589         return merge_done;
1590 }
1591
1592 /*
1593  * This function tries to merge the @ex extent to neighbours in the tree.
1594  * return 1 if merge left else 0.
1595  */
1596 static int ext4_ext_try_to_merge(struct inode *inode,
1597                                   struct ext4_ext_path *path,
1598                                   struct ext4_extent *ex) {
1599         struct ext4_extent_header *eh;
1600         unsigned int depth;
1601         int merge_done = 0;
1602         int ret = 0;
1603
1604         depth = ext_depth(inode);
1605         BUG_ON(path[depth].p_hdr == NULL);
1606         eh = path[depth].p_hdr;
1607
1608         if (ex > EXT_FIRST_EXTENT(eh))
1609                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1610
1611         if (!merge_done)
1612                 ret = ext4_ext_try_to_merge_right(inode, path, ex);
1613
1614         return ret;
1615 }
1616
1617 /*
1618  * check if a portion of the "newext" extent overlaps with an
1619  * existing extent.
1620  *
1621  * If there is an overlap discovered, it updates the length of the newext
1622  * such that there will be no overlap, and then returns 1.
1623  * If there is no overlap found, it returns 0.
1624  */
1625 static unsigned int ext4_ext_check_overlap(struct inode *inode,
1626                                            struct ext4_extent *newext,
1627                                            struct ext4_ext_path *path)
1628 {
1629         ext4_lblk_t b1, b2;
1630         unsigned int depth, len1;
1631         unsigned int ret = 0;
1632
1633         b1 = le32_to_cpu(newext->ee_block);
1634         len1 = ext4_ext_get_actual_len(newext);
1635         depth = ext_depth(inode);
1636         if (!path[depth].p_ext)
1637                 goto out;
1638         b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1639
1640         /*
1641          * get the next allocated block if the extent in the path
1642          * is before the requested block(s)
1643          */
1644         if (b2 < b1) {
1645                 b2 = ext4_ext_next_allocated_block(path);
1646                 if (b2 == EXT_MAX_BLOCKS)
1647                         goto out;
1648         }
1649
1650         /* check for wrap through zero on extent logical start block*/
1651         if (b1 + len1 < b1) {
1652                 len1 = EXT_MAX_BLOCKS - b1;
1653                 newext->ee_len = cpu_to_le16(len1);
1654                 ret = 1;
1655         }
1656
1657         /* check for overlap */
1658         if (b1 + len1 > b2) {
1659                 newext->ee_len = cpu_to_le16(b2 - b1);
1660                 ret = 1;
1661         }
1662 out:
1663         return ret;
1664 }
1665
1666 /*
1667  * ext4_ext_insert_extent:
1668  * tries to merge requsted extent into the existing extent or
1669  * inserts requested extent as new one into the tree,
1670  * creating new leaf in the no-space case.
1671  */
1672 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1673                                 struct ext4_ext_path *path,
1674                                 struct ext4_extent *newext, int flag)
1675 {
1676         struct ext4_extent_header *eh;
1677         struct ext4_extent *ex, *fex;
1678         struct ext4_extent *nearex; /* nearest extent */
1679         struct ext4_ext_path *npath = NULL;
1680         int depth, len, err;
1681         ext4_lblk_t next;
1682         unsigned uninitialized = 0;
1683         int flags = 0;
1684
1685         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1686                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1687                 return -EIO;
1688         }
1689         depth = ext_depth(inode);
1690         ex = path[depth].p_ext;
1691         if (unlikely(path[depth].p_hdr == NULL)) {
1692                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1693                 return -EIO;
1694         }
1695
1696         /* try to insert block into found extent and return */
1697         if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
1698                 && ext4_can_extents_be_merged(inode, ex, newext)) {
1699                 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
1700                           ext4_ext_is_uninitialized(newext),
1701                           ext4_ext_get_actual_len(newext),
1702                           le32_to_cpu(ex->ee_block),
1703                           ext4_ext_is_uninitialized(ex),
1704                           ext4_ext_get_actual_len(ex),
1705                           ext4_ext_pblock(ex));
1706                 err = ext4_ext_get_access(handle, inode, path + depth);
1707                 if (err)
1708                         return err;
1709
1710                 /*
1711                  * ext4_can_extents_be_merged should have checked that either
1712                  * both extents are uninitialized, or both aren't. Thus we
1713                  * need to check only one of them here.
1714                  */
1715                 if (ext4_ext_is_uninitialized(ex))
1716                         uninitialized = 1;
1717                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1718                                         + ext4_ext_get_actual_len(newext));
1719                 if (uninitialized)
1720                         ext4_ext_mark_uninitialized(ex);
1721                 eh = path[depth].p_hdr;
1722                 nearex = ex;
1723                 goto merge;
1724         }
1725
1726         depth = ext_depth(inode);
1727         eh = path[depth].p_hdr;
1728         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1729                 goto has_space;
1730
1731         /* probably next leaf has space for us? */
1732         fex = EXT_LAST_EXTENT(eh);
1733         next = EXT_MAX_BLOCKS;
1734         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
1735                 next = ext4_ext_next_leaf_block(inode, path);
1736         if (next != EXT_MAX_BLOCKS) {
1737                 ext_debug("next leaf block - %d\n", next);
1738                 BUG_ON(npath != NULL);
1739                 npath = ext4_ext_find_extent(inode, next, NULL);
1740                 if (IS_ERR(npath))
1741                         return PTR_ERR(npath);
1742                 BUG_ON(npath->p_depth != path->p_depth);
1743                 eh = npath[depth].p_hdr;
1744                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1745                         ext_debug("next leaf isn't full(%d)\n",
1746                                   le16_to_cpu(eh->eh_entries));
1747                         path = npath;
1748                         goto has_space;
1749                 }
1750                 ext_debug("next leaf has no free space(%d,%d)\n",
1751                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1752         }
1753
1754         /*
1755          * There is no free space in the found leaf.
1756          * We're gonna add a new leaf in the tree.
1757          */
1758         if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
1759                 flags = EXT4_MB_USE_ROOT_BLOCKS;
1760         err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
1761         if (err)
1762                 goto cleanup;
1763         depth = ext_depth(inode);
1764         eh = path[depth].p_hdr;
1765
1766 has_space:
1767         nearex = path[depth].p_ext;
1768
1769         err = ext4_ext_get_access(handle, inode, path + depth);
1770         if (err)
1771                 goto cleanup;
1772
1773         if (!nearex) {
1774                 /* there is no extent in this leaf, create first one */
1775                 ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n",
1776                                 le32_to_cpu(newext->ee_block),
1777                                 ext4_ext_pblock(newext),
1778                                 ext4_ext_is_uninitialized(newext),
1779                                 ext4_ext_get_actual_len(newext));
1780                 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1781         } else if (le32_to_cpu(newext->ee_block)
1782                            > le32_to_cpu(nearex->ee_block)) {
1783 /*              BUG_ON(newext->ee_block == nearex->ee_block); */
1784                 if (nearex != EXT_LAST_EXTENT(eh)) {
1785                         len = EXT_MAX_EXTENT(eh) - nearex;
1786                         len = (len - 1) * sizeof(struct ext4_extent);
1787                         len = len < 0 ? 0 : len;
1788                         ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, "
1789                                         "move %d from 0x%p to 0x%p\n",
1790                                         le32_to_cpu(newext->ee_block),
1791                                         ext4_ext_pblock(newext),
1792                                         ext4_ext_is_uninitialized(newext),
1793                                         ext4_ext_get_actual_len(newext),
1794                                         nearex, len, nearex + 1, nearex + 2);
1795                         memmove(nearex + 2, nearex + 1, len);
1796                 }
1797                 path[depth].p_ext = nearex + 1;
1798         } else {
1799                 BUG_ON(newext->ee_block == nearex->ee_block);
1800                 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1801                 len = len < 0 ? 0 : len;
1802                 ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, "
1803                                 "move %d from 0x%p to 0x%p\n",
1804                                 le32_to_cpu(newext->ee_block),
1805                                 ext4_ext_pblock(newext),
1806                                 ext4_ext_is_uninitialized(newext),
1807                                 ext4_ext_get_actual_len(newext),
1808                                 nearex, len, nearex + 1, nearex + 2);
1809                 memmove(nearex + 1, nearex, len);
1810                 path[depth].p_ext = nearex;
1811         }
1812
1813         le16_add_cpu(&eh->eh_entries, 1);
1814         nearex = path[depth].p_ext;
1815         nearex->ee_block = newext->ee_block;
1816         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
1817         nearex->ee_len = newext->ee_len;
1818
1819 merge:
1820         /* try to merge extents to the right */
1821         if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
1822                 ext4_ext_try_to_merge(inode, path, nearex);
1823
1824         /* try to merge extents to the left */
1825
1826         /* time to correct all indexes above */
1827         err = ext4_ext_correct_indexes(handle, inode, path);
1828         if (err)
1829                 goto cleanup;
1830
1831         err = ext4_ext_dirty(handle, inode, path + depth);
1832
1833 cleanup:
1834         if (npath) {
1835                 ext4_ext_drop_refs(npath);
1836                 kfree(npath);
1837         }
1838         ext4_ext_invalidate_cache(inode);
1839         return err;
1840 }
1841
1842 static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
1843                                ext4_lblk_t num, ext_prepare_callback func,
1844                                void *cbdata)
1845 {
1846         struct ext4_ext_path *path = NULL;
1847         struct ext4_ext_cache cbex;
1848         struct ext4_extent *ex;
1849         ext4_lblk_t next, start = 0, end = 0;
1850         ext4_lblk_t last = block + num;
1851         int depth, exists, err = 0;
1852
1853         BUG_ON(func == NULL);
1854         BUG_ON(inode == NULL);
1855
1856         while (block < last && block != EXT_MAX_BLOCKS) {
1857                 num = last - block;
1858                 /* find extent for this block */
1859                 down_read(&EXT4_I(inode)->i_data_sem);
1860                 path = ext4_ext_find_extent(inode, block, path);
1861                 up_read(&EXT4_I(inode)->i_data_sem);
1862                 if (IS_ERR(path)) {
1863                         err = PTR_ERR(path);
1864                         path = NULL;
1865                         break;
1866                 }
1867
1868                 depth = ext_depth(inode);
1869                 if (unlikely(path[depth].p_hdr == NULL)) {
1870                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1871                         err = -EIO;
1872                         break;
1873                 }
1874                 ex = path[depth].p_ext;
1875                 next = ext4_ext_next_allocated_block(path);
1876
1877                 exists = 0;
1878                 if (!ex) {
1879                         /* there is no extent yet, so try to allocate
1880                          * all requested space */
1881                         start = block;
1882                         end = block + num;
1883                 } else if (le32_to_cpu(ex->ee_block) > block) {
1884                         /* need to allocate space before found extent */
1885                         start = block;
1886                         end = le32_to_cpu(ex->ee_block);
1887                         if (block + num < end)
1888                                 end = block + num;
1889                 } else if (block >= le32_to_cpu(ex->ee_block)
1890                                         + ext4_ext_get_actual_len(ex)) {
1891                         /* need to allocate space after found extent */
1892                         start = block;
1893                         end = block + num;
1894                         if (end >= next)
1895                                 end = next;
1896                 } else if (block >= le32_to_cpu(ex->ee_block)) {
1897                         /*
1898                          * some part of requested space is covered
1899                          * by found extent
1900                          */
1901                         start = block;
1902                         end = le32_to_cpu(ex->ee_block)
1903                                 + ext4_ext_get_actual_len(ex);
1904                         if (block + num < end)
1905                                 end = block + num;
1906                         exists = 1;
1907                 } else {
1908                         BUG();
1909                 }
1910                 BUG_ON(end <= start);
1911
1912                 if (!exists) {
1913                         cbex.ec_block = start;
1914                         cbex.ec_len = end - start;
1915                         cbex.ec_start = 0;
1916                 } else {
1917                         cbex.ec_block = le32_to_cpu(ex->ee_block);
1918                         cbex.ec_len = ext4_ext_get_actual_len(ex);
1919                         cbex.ec_start = ext4_ext_pblock(ex);
1920                 }
1921
1922                 if (unlikely(cbex.ec_len == 0)) {
1923                         EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
1924                         err = -EIO;
1925                         break;
1926                 }
1927                 err = func(inode, next, &cbex, ex, cbdata);
1928                 ext4_ext_drop_refs(path);
1929
1930                 if (err < 0)
1931                         break;
1932
1933                 if (err == EXT_REPEAT)
1934                         continue;
1935                 else if (err == EXT_BREAK) {
1936                         err = 0;
1937                         break;
1938                 }
1939
1940                 if (ext_depth(inode) != depth) {
1941                         /* depth was changed. we have to realloc path */
1942                         kfree(path);
1943                         path = NULL;
1944                 }
1945
1946                 block = cbex.ec_block + cbex.ec_len;
1947         }
1948
1949         if (path) {
1950                 ext4_ext_drop_refs(path);
1951                 kfree(path);
1952         }
1953
1954         return err;
1955 }
1956
1957 static void
1958 ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
1959                         __u32 len, ext4_fsblk_t start)
1960 {
1961         struct ext4_ext_cache *cex;
1962         BUG_ON(len == 0);
1963         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1964         cex = &EXT4_I(inode)->i_cached_extent;
1965         cex->ec_block = block;
1966         cex->ec_len = len;
1967         cex->ec_start = start;
1968         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1969 }
1970
1971 /*
1972  * ext4_ext_put_gap_in_cache:
1973  * calculate boundaries of the gap that the requested block fits into
1974  * and cache this gap
1975  */
1976 static void
1977 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1978                                 ext4_lblk_t block)
1979 {
1980         int depth = ext_depth(inode);
1981         unsigned long len;
1982         ext4_lblk_t lblock;
1983         struct ext4_extent *ex;
1984
1985         ex = path[depth].p_ext;
1986         if (ex == NULL) {
1987                 /* there is no extent yet, so gap is [0;-] */
1988                 lblock = 0;
1989                 len = EXT_MAX_BLOCKS;
1990                 ext_debug("cache gap(whole file):");
1991         } else if (block < le32_to_cpu(ex->ee_block)) {
1992                 lblock = block;
1993                 len = le32_to_cpu(ex->ee_block) - block;
1994                 ext_debug("cache gap(before): %u [%u:%u]",
1995                                 block,
1996                                 le32_to_cpu(ex->ee_block),
1997                                  ext4_ext_get_actual_len(ex));
1998         } else if (block >= le32_to_cpu(ex->ee_block)
1999                         + ext4_ext_get_actual_len(ex)) {
2000                 ext4_lblk_t next;
2001                 lblock = le32_to_cpu(ex->ee_block)
2002                         + ext4_ext_get_actual_len(ex);
2003
2004                 next = ext4_ext_next_allocated_block(path);
2005                 ext_debug("cache gap(after): [%u:%u] %u",
2006                                 le32_to_cpu(ex->ee_block),
2007                                 ext4_ext_get_actual_len(ex),
2008                                 block);
2009                 BUG_ON(next == lblock);
2010                 len = next - lblock;
2011         } else {
2012                 lblock = len = 0;
2013                 BUG();
2014         }
2015
2016         ext_debug(" -> %u:%lu\n", lblock, len);
2017         ext4_ext_put_in_cache(inode, lblock, len, 0);
2018 }
2019
2020 /*
2021  * ext4_ext_in_cache()
2022  * Checks to see if the given block is in the cache.
2023  * If it is, the cached extent is stored in the given
2024  * cache extent pointer.  If the cached extent is a hole,
2025  * this routine should be used instead of
2026  * ext4_ext_in_cache if the calling function needs to
2027  * know the size of the hole.
2028  *
2029  * @inode: The files inode
2030  * @block: The block to look for in the cache
2031  * @ex:    Pointer where the cached extent will be stored
2032  *         if it contains block
2033  *
2034  * Return 0 if cache is invalid; 1 if the cache is valid
2035  */
2036 static int ext4_ext_check_cache(struct inode *inode, ext4_lblk_t block,
2037         struct ext4_ext_cache *ex){
2038         struct ext4_ext_cache *cex;
2039         struct ext4_sb_info *sbi;
2040         int ret = 0;
2041
2042         /*
2043          * We borrow i_block_reservation_lock to protect i_cached_extent
2044          */
2045         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
2046         cex = &EXT4_I(inode)->i_cached_extent;
2047         sbi = EXT4_SB(inode->i_sb);
2048
2049         /* has cache valid data? */
2050         if (cex->ec_len == 0)
2051                 goto errout;
2052
2053         if (in_range(block, cex->ec_block, cex->ec_len)) {
2054                 memcpy(ex, cex, sizeof(struct ext4_ext_cache));
2055                 ext_debug("%u cached by %u:%u:%llu\n",
2056                                 block,
2057                                 cex->ec_block, cex->ec_len, cex->ec_start);
2058                 ret = 1;
2059         }
2060 errout:
2061         if (!ret)
2062                 sbi->extent_cache_misses++;
2063         else
2064                 sbi->extent_cache_hits++;
2065         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
2066         return ret;
2067 }
2068
2069 /*
2070  * ext4_ext_in_cache()
2071  * Checks to see if the given block is in the cache.
2072  * If it is, the cached extent is stored in the given
2073  * extent pointer.
2074  *
2075  * @inode: The files inode
2076  * @block: The block to look for in the cache
2077  * @ex:    Pointer where the cached extent will be stored
2078  *         if it contains block
2079  *
2080  * Return 0 if cache is invalid; 1 if the cache is valid
2081  */
2082 static int
2083 ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
2084                         struct ext4_extent *ex)
2085 {
2086         struct ext4_ext_cache cex;
2087         int ret = 0;
2088
2089         if (ext4_ext_check_cache(inode, block, &cex)) {
2090                 ex->ee_block = cpu_to_le32(cex.ec_block);
2091                 ext4_ext_store_pblock(ex, cex.ec_start);
2092                 ex->ee_len = cpu_to_le16(cex.ec_len);
2093                 ret = 1;
2094         }
2095
2096         return ret;
2097 }
2098
2099
2100 /*
2101  * ext4_ext_rm_idx:
2102  * removes index from the index block.
2103  * It's used in truncate case only, thus all requests are for
2104  * last index in the block only.
2105  */
2106 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2107                         struct ext4_ext_path *path)
2108 {
2109         int err;
2110         ext4_fsblk_t leaf;
2111
2112         /* free index block */
2113         path--;
2114         leaf = ext4_idx_pblock(path->p_idx);
2115         if (unlikely(path->p_hdr->eh_entries == 0)) {
2116                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2117                 return -EIO;
2118         }
2119         err = ext4_ext_get_access(handle, inode, path);
2120         if (err)
2121                 return err;
2122         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2123         err = ext4_ext_dirty(handle, inode, path);
2124         if (err)
2125                 return err;
2126         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2127         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2128                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2129         return err;
2130 }
2131
2132 /*
2133  * ext4_ext_calc_credits_for_single_extent:
2134  * This routine returns max. credits that needed to insert an extent
2135  * to the extent tree.
2136  * When pass the actual path, the caller should calculate credits
2137  * under i_data_sem.
2138  */
2139 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2140                                                 struct ext4_ext_path *path)
2141 {
2142         if (path) {
2143                 int depth = ext_depth(inode);
2144                 int ret = 0;
2145
2146                 /* probably there is space in leaf? */
2147                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2148                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2149
2150                         /*
2151                          *  There are some space in the leaf tree, no
2152                          *  need to account for leaf block credit
2153                          *
2154                          *  bitmaps and block group descriptor blocks
2155                          *  and other metadat blocks still need to be
2156                          *  accounted.
2157                          */
2158                         /* 1 bitmap, 1 block group descriptor */
2159                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2160                         return ret;
2161                 }
2162         }
2163
2164         return ext4_chunk_trans_blocks(inode, nrblocks);
2165 }
2166
2167 /*
2168  * How many index/leaf blocks need to change/allocate to modify nrblocks?
2169  *
2170  * if nrblocks are fit in a single extent (chunk flag is 1), then
2171  * in the worse case, each tree level index/leaf need to be changed
2172  * if the tree split due to insert a new extent, then the old tree
2173  * index/leaf need to be updated too
2174  *
2175  * If the nrblocks are discontiguous, they could cause
2176  * the whole tree split more than once, but this is really rare.
2177  */
2178 int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
2179 {
2180         int index;
2181         int depth = ext_depth(inode);
2182
2183         if (chunk)
2184                 index = depth * 2;
2185         else
2186                 index = depth * 3;
2187
2188         return index;
2189 }
2190
2191 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2192                                 struct ext4_extent *ex,
2193                                 ext4_lblk_t from, ext4_lblk_t to)
2194 {
2195         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2196         int flags = EXT4_FREE_BLOCKS_FORGET;
2197
2198         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2199                 flags |= EXT4_FREE_BLOCKS_METADATA;
2200 #ifdef EXTENTS_STATS
2201         {
2202                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2203                 spin_lock(&sbi->s_ext_stats_lock);
2204                 sbi->s_ext_blocks += ee_len;
2205                 sbi->s_ext_extents++;
2206                 if (ee_len < sbi->s_ext_min)
2207                         sbi->s_ext_min = ee_len;
2208                 if (ee_len > sbi->s_ext_max)
2209                         sbi->s_ext_max = ee_len;
2210                 if (ext_depth(inode) > sbi->s_depth_max)
2211                         sbi->s_depth_max = ext_depth(inode);
2212                 spin_unlock(&sbi->s_ext_stats_lock);
2213         }
2214 #endif
2215         if (from >= le32_to_cpu(ex->ee_block)
2216             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2217                 /* tail removal */
2218                 ext4_lblk_t num;
2219                 ext4_fsblk_t start;
2220
2221                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2222                 start = ext4_ext_pblock(ex) + ee_len - num;
2223                 ext_debug("free last %u blocks starting %llu\n", num, start);
2224                 ext4_free_blocks(handle, inode, NULL, start, num, flags);
2225         } else if (from == le32_to_cpu(ex->ee_block)
2226                    && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
2227                 /* head removal */
2228                 ext4_lblk_t num;
2229                 ext4_fsblk_t start;
2230
2231                 num = to - from;
2232                 start = ext4_ext_pblock(ex);
2233
2234                 ext_debug("free first %u blocks starting %llu\n", num, start);
2235                 ext4_free_blocks(handle, inode, 0, start, num, flags);
2236
2237         } else {
2238                 printk(KERN_INFO "strange request: removal(2) "
2239                                 "%u-%u from %u:%u\n",
2240                                 from, to, le32_to_cpu(ex->ee_block), ee_len);
2241         }
2242         return 0;
2243 }
2244
2245
2246 /*
2247  * ext4_ext_rm_leaf() Removes the extents associated with the
2248  * blocks appearing between "start" and "end", and splits the extents
2249  * if "start" and "end" appear in the same extent
2250  *
2251  * @handle: The journal handle
2252  * @inode:  The files inode
2253  * @path:   The path to the leaf
2254  * @start:  The first block to remove
2255  * @end:   The last block to remove
2256  */
2257 static int
2258 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2259                 struct ext4_ext_path *path, ext4_lblk_t start,
2260                 ext4_lblk_t end)
2261 {
2262         int err = 0, correct_index = 0;
2263         int depth = ext_depth(inode), credits;
2264         struct ext4_extent_header *eh;
2265         ext4_lblk_t a, b, block;
2266         unsigned num;
2267         ext4_lblk_t ex_ee_block;
2268         unsigned short ex_ee_len;
2269         unsigned uninitialized = 0;
2270         struct ext4_extent *ex;
2271         struct ext4_map_blocks map;
2272
2273         /* the header must be checked already in ext4_ext_remove_space() */
2274         ext_debug("truncate since %u in leaf\n", start);
2275         if (!path[depth].p_hdr)
2276                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2277         eh = path[depth].p_hdr;
2278         if (unlikely(path[depth].p_hdr == NULL)) {
2279                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2280                 return -EIO;
2281         }
2282         /* find where to start removing */
2283         ex = EXT_LAST_EXTENT(eh);
2284
2285         ex_ee_block = le32_to_cpu(ex->ee_block);
2286         ex_ee_len = ext4_ext_get_actual_len(ex);
2287
2288         while (ex >= EXT_FIRST_EXTENT(eh) &&
2289                         ex_ee_block + ex_ee_len > start) {
2290
2291                 if (ext4_ext_is_uninitialized(ex))
2292                         uninitialized = 1;
2293                 else
2294                         uninitialized = 0;
2295
2296                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2297                          uninitialized, ex_ee_len);
2298                 path[depth].p_ext = ex;
2299
2300                 a = ex_ee_block > start ? ex_ee_block : start;
2301                 b = ex_ee_block+ex_ee_len - 1 < end ?
2302                         ex_ee_block+ex_ee_len - 1 : end;
2303
2304                 ext_debug("  border %u:%u\n", a, b);
2305
2306                 /* If this extent is beyond the end of the hole, skip it */
2307                 if (end <= ex_ee_block) {
2308                         ex--;
2309                         ex_ee_block = le32_to_cpu(ex->ee_block);
2310                         ex_ee_len = ext4_ext_get_actual_len(ex);
2311                         continue;
2312                 } else if (a != ex_ee_block &&
2313                         b != ex_ee_block + ex_ee_len - 1) {
2314                         /*
2315                          * If this is a truncate, then this condition should
2316                          * never happen because at least one of the end points
2317                          * needs to be on the edge of the extent.
2318                          */
2319                         if (end == EXT_MAX_BLOCKS - 1) {
2320                                 ext_debug("  bad truncate %u:%u\n",
2321                                                 start, end);
2322                                 block = 0;
2323                                 num = 0;
2324                                 err = -EIO;
2325                                 goto out;
2326                         }
2327                         /*
2328                          * else this is a hole punch, so the extent needs to
2329                          * be split since neither edge of the hole is on the
2330                          * extent edge
2331                          */
2332                         else{
2333                                 map.m_pblk = ext4_ext_pblock(ex);
2334                                 map.m_lblk = ex_ee_block;
2335                                 map.m_len = b - ex_ee_block;
2336
2337                                 err = ext4_split_extent(handle,
2338                                         inode, path, &map, 0,
2339                                         EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
2340                                         EXT4_GET_BLOCKS_PRE_IO);
2341
2342                                 if (err < 0)
2343                                         goto out;
2344
2345                                 ex_ee_len = ext4_ext_get_actual_len(ex);
2346
2347                                 b = ex_ee_block+ex_ee_len - 1 < end ?
2348                                         ex_ee_block+ex_ee_len - 1 : end;
2349
2350                                 /* Then remove tail of this extent */
2351                                 block = ex_ee_block;
2352                                 num = a - block;
2353                         }
2354                 } else if (a != ex_ee_block) {
2355                         /* remove tail of the extent */
2356                         block = ex_ee_block;
2357                         num = a - block;
2358                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2359                         /* remove head of the extent */
2360                         block = b;
2361                         num =  ex_ee_block + ex_ee_len - b;
2362
2363                         /*
2364                          * If this is a truncate, this condition
2365                          * should never happen
2366                          */
2367                         if (end == EXT_MAX_BLOCKS - 1) {
2368                                 ext_debug("  bad truncate %u:%u\n",
2369                                         start, end);
2370                                 err = -EIO;
2371                                 goto out;
2372                         }
2373                 } else {
2374                         /* remove whole extent: excellent! */
2375                         block = ex_ee_block;
2376                         num = 0;
2377                         if (a != ex_ee_block) {
2378                                 ext_debug("  bad truncate %u:%u\n",
2379                                         start, end);
2380                                 err = -EIO;
2381                                 goto out;
2382                         }
2383
2384                         if (b != ex_ee_block + ex_ee_len - 1) {
2385                                 ext_debug("  bad truncate %u:%u\n",
2386                                         start, end);
2387                                 err = -EIO;
2388                                 goto out;
2389                         }
2390                 }
2391
2392                 /*
2393                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2394                  * descriptor) for each block group; assume two block
2395                  * groups plus ex_ee_len/blocks_per_block_group for
2396                  * the worst case
2397                  */
2398                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2399                 if (ex == EXT_FIRST_EXTENT(eh)) {
2400                         correct_index = 1;
2401                         credits += (ext_depth(inode)) + 1;
2402                 }
2403                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2404
2405                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2406                 if (err)
2407                         goto out;
2408
2409                 err = ext4_ext_get_access(handle, inode, path + depth);
2410                 if (err)
2411                         goto out;
2412
2413                 err = ext4_remove_blocks(handle, inode, ex, a, b);
2414                 if (err)
2415                         goto out;
2416
2417                 if (num == 0) {
2418                         /* this extent is removed; mark slot entirely unused */
2419                         ext4_ext_store_pblock(ex, 0);
2420                 } else if (block != ex_ee_block) {
2421                         /*
2422                          * If this was a head removal, then we need to update
2423                          * the physical block since it is now at a different
2424                          * location
2425                          */
2426                         ext4_ext_store_pblock(ex, ext4_ext_pblock(ex) + (b-a));
2427                 }
2428
2429                 ex->ee_block = cpu_to_le32(block);
2430                 ex->ee_len = cpu_to_le16(num);
2431                 /*
2432                  * Do not mark uninitialized if all the blocks in the
2433                  * extent have been removed.
2434                  */
2435                 if (uninitialized && num)
2436                         ext4_ext_mark_uninitialized(ex);
2437
2438                 err = ext4_ext_dirty(handle, inode, path + depth);
2439                 if (err)
2440                         goto out;
2441
2442                 /*
2443                  * If the extent was completely released,
2444                  * we need to remove it from the leaf
2445                  */
2446                 if (num == 0) {
2447                         if (end != EXT_MAX_BLOCKS - 1) {
2448                                 /*
2449                                  * For hole punching, we need to scoot all the
2450                                  * extents up when an extent is removed so that
2451                                  * we dont have blank extents in the middle
2452                                  */
2453                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2454                                         sizeof(struct ext4_extent));
2455
2456                                 /* Now get rid of the one at the end */
2457                                 memset(EXT_LAST_EXTENT(eh), 0,
2458                                         sizeof(struct ext4_extent));
2459                         }
2460                         le16_add_cpu(&eh->eh_entries, -1);
2461                 }
2462
2463                 ext_debug("new extent: %u:%u:%llu\n", block, num,
2464                                 ext4_ext_pblock(ex));
2465                 ex--;
2466                 ex_ee_block = le32_to_cpu(ex->ee_block);
2467                 ex_ee_len = ext4_ext_get_actual_len(ex);
2468         }
2469
2470         if (correct_index && eh->eh_entries)
2471                 err = ext4_ext_correct_indexes(handle, inode, path);
2472
2473         /* if this leaf is free, then we should
2474          * remove it from index block above */
2475         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2476                 err = ext4_ext_rm_idx(handle, inode, path + depth);
2477
2478 out:
2479         return err;
2480 }
2481
2482 /*
2483  * ext4_ext_more_to_rm:
2484  * returns 1 if current index has to be freed (even partial)
2485  */
2486 static int
2487 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2488 {
2489         BUG_ON(path->p_idx == NULL);
2490
2491         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2492                 return 0;
2493
2494         /*
2495          * if truncate on deeper level happened, it wasn't partial,
2496          * so we have to consider current index for truncation
2497          */
2498         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2499                 return 0;
2500         return 1;
2501 }
2502
2503 static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
2504 {
2505         struct super_block *sb = inode->i_sb;
2506         int depth = ext_depth(inode);
2507         struct ext4_ext_path *path;
2508         handle_t *handle;
2509         int i, err;
2510
2511         ext_debug("truncate since %u\n", start);
2512
2513         /* probably first extent we're gonna free will be last in block */
2514         handle = ext4_journal_start(inode, depth + 1);
2515         if (IS_ERR(handle))
2516                 return PTR_ERR(handle);
2517
2518 again:
2519         ext4_ext_invalidate_cache(inode);
2520
2521         /*
2522          * We start scanning from right side, freeing all the blocks
2523          * after i_size and walking into the tree depth-wise.
2524          */
2525         depth = ext_depth(inode);
2526         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
2527         if (path == NULL) {
2528                 ext4_journal_stop(handle);
2529                 return -ENOMEM;
2530         }
2531         path[0].p_depth = depth;
2532         path[0].p_hdr = ext_inode_hdr(inode);
2533         if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
2534                 err = -EIO;
2535                 goto out;
2536         }
2537         i = err = 0;
2538
2539         while (i >= 0 && err == 0) {
2540                 if (i == depth) {
2541                         /* this is leaf block */
2542                         err = ext4_ext_rm_leaf(handle, inode, path,
2543                                         start, EXT_MAX_BLOCKS - 1);
2544                         /* root level has p_bh == NULL, brelse() eats this */
2545                         brelse(path[i].p_bh);
2546                         path[i].p_bh = NULL;
2547                         i--;
2548                         continue;
2549                 }
2550
2551                 /* this is index block */
2552                 if (!path[i].p_hdr) {
2553                         ext_debug("initialize header\n");
2554                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2555                 }
2556
2557                 if (!path[i].p_idx) {
2558                         /* this level hasn't been touched yet */
2559                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2560                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2561                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2562                                   path[i].p_hdr,
2563                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2564                 } else {
2565                         /* we were already here, see at next index */
2566                         path[i].p_idx--;
2567                 }
2568
2569                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2570                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2571                                 path[i].p_idx);
2572                 if (ext4_ext_more_to_rm(path + i)) {
2573                         struct buffer_head *bh;
2574                         /* go to the next level */
2575                         ext_debug("move to level %d (block %llu)\n",
2576                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2577                         memset(path + i + 1, 0, sizeof(*path));
2578                         bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
2579                         if (!bh) {
2580                                 /* should we reset i_size? */
2581                                 err = -EIO;
2582                                 break;
2583                         }
2584                         if (WARN_ON(i + 1 > depth)) {
2585                                 err = -EIO;
2586                                 break;
2587                         }
2588                         if (ext4_ext_check(inode, ext_block_hdr(bh),
2589                                                         depth - i - 1)) {
2590                                 err = -EIO;
2591                                 break;
2592                         }
2593                         path[i + 1].p_bh = bh;
2594
2595                         /* save actual number of indexes since this
2596                          * number is changed at the next iteration */
2597                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2598                         i++;
2599                 } else {
2600                         /* we finished processing this index, go up */
2601                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2602                                 /* index is empty, remove it;
2603                                  * handle must be already prepared by the
2604                                  * truncatei_leaf() */
2605                                 err = ext4_ext_rm_idx(handle, inode, path + i);
2606                         }
2607                         /* root level has p_bh == NULL, brelse() eats this */
2608                         brelse(path[i].p_bh);
2609                         path[i].p_bh = NULL;
2610                         i--;
2611                         ext_debug("return to level %d\n", i);
2612                 }
2613         }
2614
2615         /* TODO: flexible tree reduction should be here */
2616         if (path->p_hdr->eh_entries == 0) {
2617                 /*
2618                  * truncate to zero freed all the tree,
2619                  * so we need to correct eh_depth
2620                  */
2621                 err = ext4_ext_get_access(handle, inode, path);
2622                 if (err == 0) {
2623                         ext_inode_hdr(inode)->eh_depth = 0;
2624                         ext_inode_hdr(inode)->eh_max =
2625                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
2626                         err = ext4_ext_dirty(handle, inode, path);
2627                 }
2628         }
2629 out:
2630         ext4_ext_drop_refs(path);
2631         kfree(path);
2632         if (err == -EAGAIN)
2633                 goto again;
2634         ext4_journal_stop(handle);
2635
2636         return err;
2637 }
2638
2639 /*
2640  * called at mount time
2641  */
2642 void ext4_ext_init(struct super_block *sb)
2643 {
2644         /*
2645          * possible initialization would be here
2646          */
2647
2648         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
2649 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
2650                 printk(KERN_INFO "EXT4-fs: file extents enabled");
2651 #ifdef AGGRESSIVE_TEST
2652                 printk(", aggressive tests");
2653 #endif
2654 #ifdef CHECK_BINSEARCH
2655                 printk(", check binsearch");
2656 #endif
2657 #ifdef EXTENTS_STATS
2658                 printk(", stats");
2659 #endif
2660                 printk("\n");
2661 #endif
2662 #ifdef EXTENTS_STATS
2663                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2664                 EXT4_SB(sb)->s_ext_min = 1 << 30;
2665                 EXT4_SB(sb)->s_ext_max = 0;
2666 #endif
2667         }
2668 }
2669
2670 /*
2671  * called at umount time
2672  */
2673 void ext4_ext_release(struct super_block *sb)
2674 {
2675         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
2676                 return;
2677
2678 #ifdef EXTENTS_STATS
2679         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2680                 struct ext4_sb_info *sbi = EXT4_SB(sb);
2681                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2682                         sbi->s_ext_blocks, sbi->s_ext_extents,
2683                         sbi->s_ext_blocks / sbi->s_ext_extents);
2684                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2685                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2686         }
2687 #endif
2688 }
2689
2690 /* FIXME!! we need to try to merge to left or right after zero-out  */
2691 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
2692 {
2693         ext4_fsblk_t ee_pblock;
2694         unsigned int ee_len;
2695         int ret;
2696
2697         ee_len    = ext4_ext_get_actual_len(ex);
2698         ee_pblock = ext4_ext_pblock(ex);
2699
2700         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
2701         if (ret > 0)
2702                 ret = 0;
2703
2704         return ret;
2705 }
2706
2707 /*
2708  * used by extent splitting.
2709  */
2710 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
2711                                         due to ENOSPC */
2712 #define EXT4_EXT_MARK_UNINIT1   0x2  /* mark first half uninitialized */
2713 #define EXT4_EXT_MARK_UNINIT2   0x4  /* mark second half uninitialized */
2714
2715 /*
2716  * ext4_split_extent_at() splits an extent at given block.
2717  *
2718  * @handle: the journal handle
2719  * @inode: the file inode
2720  * @path: the path to the extent
2721  * @split: the logical block where the extent is splitted.
2722  * @split_flags: indicates if the extent could be zeroout if split fails, and
2723  *               the states(init or uninit) of new extents.
2724  * @flags: flags used to insert new extent to extent tree.
2725  *
2726  *
2727  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
2728  * of which are deterimined by split_flag.
2729  *
2730  * There are two cases:
2731  *  a> the extent are splitted into two extent.
2732  *  b> split is not needed, and just mark the extent.
2733  *
2734  * return 0 on success.
2735  */
2736 static int ext4_split_extent_at(handle_t *handle,
2737                              struct inode *inode,
2738                              struct ext4_ext_path *path,
2739                              ext4_lblk_t split,
2740                              int split_flag,
2741                              int flags)
2742 {
2743         ext4_fsblk_t newblock;
2744         ext4_lblk_t ee_block;
2745         struct ext4_extent *ex, newex, orig_ex;
2746         struct ext4_extent *ex2 = NULL;
2747         unsigned int ee_len, depth;
2748         int err = 0;
2749
2750         ext_debug("ext4_split_extents_at: inode %lu, logical"
2751                 "block %llu\n", inode->i_ino, (unsigned long long)split);
2752
2753         ext4_ext_show_leaf(inode, path);
2754
2755         depth = ext_depth(inode);
2756         ex = path[depth].p_ext;
2757         ee_block = le32_to_cpu(ex->ee_block);
2758         ee_len = ext4_ext_get_actual_len(ex);
2759         newblock = split - ee_block + ext4_ext_pblock(ex);
2760
2761         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
2762
2763         err = ext4_ext_get_access(handle, inode, path + depth);
2764         if (err)
2765                 goto out;
2766
2767         if (split == ee_block) {
2768                 /*
2769                  * case b: block @split is the block that the extent begins with
2770                  * then we just change the state of the extent, and splitting
2771                  * is not needed.
2772                  */
2773                 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2774                         ext4_ext_mark_uninitialized(ex);
2775                 else
2776                         ext4_ext_mark_initialized(ex);
2777
2778                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
2779                         ext4_ext_try_to_merge(inode, path, ex);
2780
2781                 err = ext4_ext_dirty(handle, inode, path + depth);
2782                 goto out;
2783         }
2784
2785         /* case a */
2786         memcpy(&orig_ex, ex, sizeof(orig_ex));
2787         ex->ee_len = cpu_to_le16(split - ee_block);
2788         if (split_flag & EXT4_EXT_MARK_UNINIT1)
2789                 ext4_ext_mark_uninitialized(ex);
2790
2791         /*
2792          * path may lead to new leaf, not to original leaf any more
2793          * after ext4_ext_insert_extent() returns,
2794          */
2795         err = ext4_ext_dirty(handle, inode, path + depth);
2796         if (err)
2797                 goto fix_extent_len;
2798
2799         ex2 = &newex;
2800         ex2->ee_block = cpu_to_le32(split);
2801         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
2802         ext4_ext_store_pblock(ex2, newblock);
2803         if (split_flag & EXT4_EXT_MARK_UNINIT2)
2804                 ext4_ext_mark_uninitialized(ex2);
2805
2806         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
2807         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2808                 err = ext4_ext_zeroout(inode, &orig_ex);
2809                 if (err)
2810                         goto fix_extent_len;
2811                 /* update the extent length and mark as initialized */
2812                 ex->ee_len = cpu_to_le32(ee_len);
2813                 ext4_ext_try_to_merge(inode, path, ex);
2814                 err = ext4_ext_dirty(handle, inode, path + depth);
2815                 goto out;
2816         } else if (err)
2817                 goto fix_extent_len;
2818
2819 out:
2820         ext4_ext_show_leaf(inode, path);
2821         return err;
2822
2823 fix_extent_len:
2824         ex->ee_len = orig_ex.ee_len;
2825         ext4_ext_dirty(handle, inode, path + depth);
2826         return err;
2827 }
2828
2829 /*
2830  * ext4_split_extents() splits an extent and mark extent which is covered
2831  * by @map as split_flags indicates
2832  *
2833  * It may result in splitting the extent into multiple extents (upto three)
2834  * There are three possibilities:
2835  *   a> There is no split required
2836  *   b> Splits in two extents: Split is happening at either end of the extent
2837  *   c> Splits in three extents: Somone is splitting in middle of the extent
2838  *
2839  */
2840 static int ext4_split_extent(handle_t *handle,
2841                               struct inode *inode,
2842                               struct ext4_ext_path *path,
2843                               struct ext4_map_blocks *map,
2844                               int split_flag,
2845                               int flags)
2846 {
2847         ext4_lblk_t ee_block;
2848         struct ext4_extent *ex;
2849         unsigned int ee_len, depth;
2850         int err = 0;
2851         int uninitialized;
2852         int split_flag1, flags1;
2853
2854         depth = ext_depth(inode);
2855         ex = path[depth].p_ext;
2856         ee_block = le32_to_cpu(ex->ee_block);
2857         ee_len = ext4_ext_get_actual_len(ex);
2858         uninitialized = ext4_ext_is_uninitialized(ex);
2859
2860         if (map->m_lblk + map->m_len < ee_block + ee_len) {
2861                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2862                               EXT4_EXT_MAY_ZEROOUT : 0;
2863                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
2864                 if (uninitialized)
2865                         split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
2866                                        EXT4_EXT_MARK_UNINIT2;
2867                 err = ext4_split_extent_at(handle, inode, path,
2868                                 map->m_lblk + map->m_len, split_flag1, flags1);
2869                 if (err)
2870                         goto out;
2871         }
2872
2873         ext4_ext_drop_refs(path);
2874         path = ext4_ext_find_extent(inode, map->m_lblk, path);
2875         if (IS_ERR(path))
2876                 return PTR_ERR(path);
2877
2878         if (map->m_lblk >= ee_block) {
2879                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
2880                               EXT4_EXT_MAY_ZEROOUT : 0;
2881                 if (uninitialized)
2882                         split_flag1 |= EXT4_EXT_MARK_UNINIT1;
2883                 if (split_flag & EXT4_EXT_MARK_UNINIT2)
2884                         split_flag1 |= EXT4_EXT_MARK_UNINIT2;
2885                 err = ext4_split_extent_at(handle, inode, path,
2886                                 map->m_lblk, split_flag1, flags);
2887                 if (err)
2888                         goto out;
2889         }
2890
2891         ext4_ext_show_leaf(inode, path);
2892 out:
2893         return err ? err : map->m_len;
2894 }
2895
2896 #define EXT4_EXT_ZERO_LEN 7
2897 /*
2898  * This function is called by ext4_ext_map_blocks() if someone tries to write
2899  * to an uninitialized extent. It may result in splitting the uninitialized
2900  * extent into multiple extents (up to three - one initialized and two
2901  * uninitialized).
2902  * There are three possibilities:
2903  *   a> There is no split required: Entire extent should be initialized
2904  *   b> Splits in two extents: Write is happening at either end of the extent
2905  *   c> Splits in three extents: Somone is writing in middle of the extent
2906  */
2907 static int ext4_ext_convert_to_initialized(handle_t *handle,
2908                                            struct inode *inode,
2909                                            struct ext4_map_blocks *map,
2910                                            struct ext4_ext_path *path)
2911 {
2912         struct ext4_map_blocks split_map;
2913         struct ext4_extent zero_ex;
2914         struct ext4_extent *ex;
2915         ext4_lblk_t ee_block, eof_block;
2916         unsigned int allocated, ee_len, depth;
2917         int err = 0;
2918         int split_flag = 0;
2919
2920         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
2921                 "block %llu, max_blocks %u\n", inode->i_ino,
2922                 (unsigned long long)map->m_lblk, map->m_len);
2923
2924         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
2925                 inode->i_sb->s_blocksize_bits;
2926         if (eof_block < map->m_lblk + map->m_len)
2927                 eof_block = map->m_lblk + map->m_len;
2928
2929         depth = ext_depth(inode);
2930         ex = path[depth].p_ext;
2931         ee_block = le32_to_cpu(ex->ee_block);
2932         ee_len = ext4_ext_get_actual_len(ex);
2933         allocated = ee_len - (map->m_lblk - ee_block);
2934
2935         WARN_ON(map->m_lblk < ee_block);
2936         /*
2937          * It is safe to convert extent to initialized via explicit
2938          * zeroout only if extent is fully insde i_size or new_size.
2939          */
2940         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
2941
2942         /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
2943         if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
2944             (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2945                 err = ext4_ext_zeroout(inode, ex);
2946                 if (err)
2947                         goto out;
2948
2949                 err = ext4_ext_get_access(handle, inode, path + depth);
2950                 if (err)
2951                         goto out;
2952                 ext4_ext_mark_initialized(ex);
2953                 ext4_ext_try_to_merge(inode, path, ex);
2954                 err = ext4_ext_dirty(handle, inode, path + depth);
2955                 goto out;
2956         }
2957
2958         /*
2959          * four cases:
2960          * 1. split the extent into three extents.
2961          * 2. split the extent into two extents, zeroout the first half.
2962          * 3. split the extent into two extents, zeroout the second half.
2963          * 4. split the extent into two extents with out zeroout.
2964          */
2965         split_map.m_lblk = map->m_lblk;
2966         split_map.m_len = map->m_len;
2967
2968         if (allocated > map->m_len) {
2969                 if (allocated <= EXT4_EXT_ZERO_LEN &&
2970                     (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2971                         /* case 3 */
2972                         zero_ex.ee_block =
2973                                          cpu_to_le32(map->m_lblk);
2974                         zero_ex.ee_len = cpu_to_le16(allocated);
2975                         ext4_ext_store_pblock(&zero_ex,
2976                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
2977                         err = ext4_ext_zeroout(inode, &zero_ex);
2978                         if (err)
2979                                 goto out;
2980                         split_map.m_lblk = map->m_lblk;
2981                         split_map.m_len = allocated;
2982                 } else if ((map->m_lblk - ee_block + map->m_len <
2983                            EXT4_EXT_ZERO_LEN) &&
2984                            (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
2985                         /* case 2 */
2986                         if (map->m_lblk != ee_block) {
2987                                 zero_ex.ee_block = ex->ee_block;
2988                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
2989                                                         ee_block);
2990                                 ext4_ext_store_pblock(&zero_ex,
2991                                                       ext4_ext_pblock(ex));
2992                                 err = ext4_ext_zeroout(inode, &zero_ex);
2993                                 if (err)
2994                                         goto out;
2995                         }
2996
2997                         split_map.m_lblk = ee_block;
2998                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
2999                         allocated = map->m_len;
3000                 }
3001         }
3002
3003         allocated = ext4_split_extent(handle, inode, path,
3004                                        &split_map, split_flag, 0);
3005         if (allocated < 0)
3006                 err = allocated;
3007
3008 out:
3009         return err ? err : allocated;
3010 }
3011
3012 /*
3013  * This function is called by ext4_ext_map_blocks() from
3014  * ext4_get_blocks_dio_write() when DIO to write
3015  * to an uninitialized extent.
3016  *
3017  * Writing to an uninitialized extent may result in splitting the uninitialized
3018  * extent into multiple /initialized uninitialized extents (up to three)
3019  * There are three possibilities:
3020  *   a> There is no split required: Entire extent should be uninitialized
3021  *   b> Splits in two extents: Write is happening at either end of the extent
3022  *   c> Splits in three extents: Somone is writing in middle of the extent
3023  *
3024  * One of more index blocks maybe needed if the extent tree grow after
3025  * the uninitialized extent split. To prevent ENOSPC occur at the IO
3026  * complete, we need to split the uninitialized extent before DIO submit
3027  * the IO. The uninitialized extent called at this time will be split
3028  * into three uninitialized extent(at most). After IO complete, the part
3029  * being filled will be convert to initialized by the end_io callback function
3030  * via ext4_convert_unwritten_extents().
3031  *
3032  * Returns the size of uninitialized extent to be written on success.
3033  */
3034 static int ext4_split_unwritten_extents(handle_t *handle,
3035                                         struct inode *inode,
3036                                         struct ext4_map_blocks *map,
3037                                         struct ext4_ext_path *path,
3038                                         int flags)
3039 {
3040         ext4_lblk_t eof_block;
3041         ext4_lblk_t ee_block;
3042         struct ext4_extent *ex;
3043         unsigned int ee_len;
3044         int split_flag = 0, depth;
3045
3046         ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3047                 "block %llu, max_blocks %u\n", inode->i_ino,
3048                 (unsigned long long)map->m_lblk, map->m_len);
3049
3050         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3051                 inode->i_sb->s_blocksize_bits;
3052         if (eof_block < map->m_lblk + map->m_len)
3053                 eof_block = map->m_lblk + map->m_len;
3054         /*
3055          * It is safe to convert extent to initialized via explicit
3056          * zeroout only if extent is fully insde i_size or new_size.
3057          */
3058         depth = ext_depth(inode);
3059         ex = path[depth].p_ext;
3060         ee_block = le32_to_cpu(ex->ee_block);
3061         ee_len = ext4_ext_get_actual_len(ex);
3062
3063         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3064         split_flag |= EXT4_EXT_MARK_UNINIT2;
3065
3066         flags |= EXT4_GET_BLOCKS_PRE_IO;
3067         return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3068 }
3069
3070 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3071                                               struct inode *inode,
3072                                               struct ext4_ext_path *path)
3073 {
3074         struct ext4_extent *ex;
3075         int depth;
3076         int err = 0;
3077
3078         depth = ext_depth(inode);
3079         ex = path[depth].p_ext;
3080
3081         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3082                 "block %llu, max_blocks %u\n", inode->i_ino,
3083                 (unsigned long long)le32_to_cpu(ex->ee_block),
3084                 ext4_ext_get_actual_len(ex));
3085
3086         err = ext4_ext_get_access(handle, inode, path + depth);
3087         if (err)
3088                 goto out;
3089         /* first mark the extent as initialized */
3090         ext4_ext_mark_initialized(ex);
3091
3092         /* note: ext4_ext_correct_indexes() isn't needed here because
3093          * borders are not changed
3094          */
3095         ext4_ext_try_to_merge(inode, path, ex);
3096
3097         /* Mark modified extent as dirty */
3098         err = ext4_ext_dirty(handle, inode, path + depth);
3099 out:
3100         ext4_ext_show_leaf(inode, path);
3101         return err;
3102 }
3103
3104 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3105                         sector_t block, int count)
3106 {
3107         int i;
3108         for (i = 0; i < count; i++)
3109                 unmap_underlying_metadata(bdev, block + i);
3110 }
3111
3112 /*
3113  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3114  */
3115 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3116                               ext4_lblk_t lblk,
3117                               struct ext4_ext_path *path,
3118                               unsigned int len)
3119 {
3120         int i, depth;
3121         struct ext4_extent_header *eh;
3122         struct ext4_extent *last_ex;
3123
3124         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3125                 return 0;
3126
3127         depth = ext_depth(inode);
3128         eh = path[depth].p_hdr;
3129
3130         if (unlikely(!eh->eh_entries)) {
3131                 EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
3132                                  "EOFBLOCKS_FL set");
3133                 return -EIO;
3134         }
3135         last_ex = EXT_LAST_EXTENT(eh);
3136         /*
3137          * We should clear the EOFBLOCKS_FL flag if we are writing the
3138          * last block in the last extent in the file.  We test this by
3139          * first checking to see if the caller to
3140          * ext4_ext_get_blocks() was interested in the last block (or
3141          * a block beyond the last block) in the current extent.  If
3142          * this turns out to be false, we can bail out from this
3143          * function immediately.
3144          */
3145         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3146             ext4_ext_get_actual_len(last_ex))
3147                 return 0;
3148         /*
3149          * If the caller does appear to be planning to write at or
3150          * beyond the end of the current extent, we then test to see
3151          * if the current extent is the last extent in the file, by
3152          * checking to make sure it was reached via the rightmost node
3153          * at each level of the tree.
3154          */
3155         for (i = depth-1; i >= 0; i--)
3156                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3157                         return 0;
3158         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3159         return ext4_mark_inode_dirty(handle, inode);
3160 }
3161
3162 static int
3163 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3164                         struct ext4_map_blocks *map,
3165                         struct ext4_ext_path *path, int flags,
3166                         unsigned int allocated, ext4_fsblk_t newblock)
3167 {
3168         int ret = 0;
3169         int err = 0;
3170         ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3171
3172         ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
3173                   "block %llu, max_blocks %u, flags %d, allocated %u",
3174                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3175                   flags, allocated);
3176         ext4_ext_show_leaf(inode, path);
3177
3178         /* get_block() before submit the IO, split the extent */
3179         if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3180                 ret = ext4_split_unwritten_extents(handle, inode, map,
3181                                                    path, flags);
3182                 /*
3183                  * Flag the inode(non aio case) or end_io struct (aio case)
3184                  * that this IO needs to conversion to written when IO is
3185                  * completed
3186                  */
3187                 if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3188                         io->flag = EXT4_IO_END_UNWRITTEN;
3189                         atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3190                 } else
3191                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3192                 if (ext4_should_dioread_nolock(inode))
3193                         map->m_flags |= EXT4_MAP_UNINIT;
3194                 goto out;
3195         }
3196         /* IO end_io complete, convert the filled extent to written */
3197         if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3198                 ret = ext4_convert_unwritten_extents_endio(handle, inode,
3199                                                         path);
3200                 if (ret >= 0) {
3201                         ext4_update_inode_fsync_trans(handle, inode, 1);
3202                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
3203                                                  path, map->m_len);
3204                 } else
3205                         err = ret;
3206                 goto out2;
3207         }
3208         /* buffered IO case */
3209         /*
3210          * repeat fallocate creation request
3211          * we already have an unwritten extent
3212          */
3213         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
3214                 goto map_out;
3215
3216         /* buffered READ or buffered write_begin() lookup */
3217         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3218                 /*
3219                  * We have blocks reserved already.  We
3220                  * return allocated blocks so that delalloc
3221                  * won't do block reservation for us.  But
3222                  * the buffer head will be unmapped so that
3223                  * a read from the block returns 0s.
3224                  */
3225                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3226                 goto out1;
3227         }
3228
3229         /* buffered write, writepage time, convert*/
3230         ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
3231         if (ret >= 0) {
3232                 ext4_update_inode_fsync_trans(handle, inode, 1);
3233                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3234                                          map->m_len);
3235                 if (err < 0)
3236                         goto out2;
3237         }
3238
3239 out:
3240         if (ret <= 0) {
3241                 err = ret;
3242                 goto out2;
3243         } else
3244                 allocated = ret;
3245         map->m_flags |= EXT4_MAP_NEW;
3246         /*
3247          * if we allocated more blocks than requested
3248          * we need to make sure we unmap the extra block
3249          * allocated. The actual needed block will get
3250          * unmapped later when we find the buffer_head marked
3251          * new.
3252          */
3253         if (allocated > map->m_len) {
3254                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3255                                         newblock + map->m_len,
3256                                         allocated - map->m_len);
3257                 allocated = map->m_len;
3258         }
3259
3260         /*
3261          * If we have done fallocate with the offset that is already
3262          * delayed allocated, we would have block reservation
3263          * and quota reservation done in the delayed write path.
3264          * But fallocate would have already updated quota and block
3265          * count for this offset. So cancel these reservation
3266          */
3267         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3268                 ext4_da_update_reserve_space(inode, allocated, 0);
3269
3270 map_out:
3271         map->m_flags |= EXT4_MAP_MAPPED;
3272 out1:
3273         if (allocated > map->m_len)
3274                 allocated = map->m_len;
3275         ext4_ext_show_leaf(inode, path);
3276         map->m_pblk = newblock;
3277         map->m_len = allocated;
3278 out2:
3279         if (path) {
3280                 ext4_ext_drop_refs(path);
3281                 kfree(path);
3282         }
3283         return err ? err : allocated;
3284 }
3285
3286 /*
3287  * Block allocation/map/preallocation routine for extents based files
3288  *
3289  *
3290  * Need to be called with
3291  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
3292  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
3293  *
3294  * return > 0, number of of blocks already mapped/allocated
3295  *          if create == 0 and these are pre-allocated blocks
3296  *              buffer head is unmapped
3297  *          otherwise blocks are mapped
3298  *
3299  * return = 0, if plain look up failed (blocks have not been allocated)
3300  *          buffer head is unmapped
3301  *
3302  * return < 0, error case.
3303  */
3304 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
3305                         struct ext4_map_blocks *map, int flags)
3306 {
3307         struct ext4_ext_path *path = NULL;
3308         struct ext4_extent newex, *ex;
3309         ext4_fsblk_t newblock = 0;
3310         int err = 0, depth, ret;
3311         unsigned int allocated = 0;
3312         unsigned int punched_out = 0;
3313         unsigned int result = 0;
3314         struct ext4_allocation_request ar;
3315         ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
3316         struct ext4_map_blocks punch_map;
3317
3318         ext_debug("blocks %u/%u requested for inode %lu\n",
3319                   map->m_lblk, map->m_len, inode->i_ino);
3320         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
3321
3322         /* check in cache */
3323         if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
3324                 ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
3325                 if (!newex.ee_start_lo && !newex.ee_start_hi) {
3326                         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3327                                 /*
3328                                  * block isn't allocated yet and
3329                                  * user doesn't want to allocate it
3330                                  */
3331                                 goto out2;
3332                         }
3333                         /* we should allocate requested block */
3334                 } else {
3335                         /* block is already allocated */
3336                         newblock = map->m_lblk
3337                                    - le32_to_cpu(newex.ee_block)
3338                                    + ext4_ext_pblock(&newex);
3339                         /* number of remaining blocks in the extent */
3340                         allocated = ext4_ext_get_actual_len(&newex) -
3341                                 (map->m_lblk - le32_to_cpu(newex.ee_block));
3342                         goto out;
3343                 }
3344         }
3345
3346         /* find extent for this block */
3347         path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
3348         if (IS_ERR(path)) {
3349                 err = PTR_ERR(path);
3350                 path = NULL;
3351                 goto out2;
3352         }
3353
3354         depth = ext_depth(inode);
3355
3356         /*
3357          * consistent leaf must not be empty;
3358          * this situation is possible, though, _during_ tree modification;
3359          * this is why assert can't be put in ext4_ext_find_extent()
3360          */
3361         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
3362                 EXT4_ERROR_INODE(inode, "bad extent address "
3363                                  "lblock: %lu, depth: %d pblock %lld",
3364                                  (unsigned long) map->m_lblk, depth,
3365                                  path[depth].p_block);
3366                 err = -EIO;
3367                 goto out2;
3368         }
3369
3370         ex = path[depth].p_ext;
3371         if (ex) {
3372                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
3373                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
3374                 unsigned short ee_len;
3375
3376                 /*
3377                  * Uninitialized extents are treated as holes, except that
3378                  * we split out initialized portions during a write.
3379                  */
3380                 ee_len = ext4_ext_get_actual_len(ex);
3381                 /* if found extent covers block, simply return it */
3382                 if (in_range(map->m_lblk, ee_block, ee_len)) {
3383                         newblock = map->m_lblk - ee_block + ee_start;
3384                         /* number of remaining blocks in the extent */
3385                         allocated = ee_len - (map->m_lblk - ee_block);
3386                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
3387                                   ee_block, ee_len, newblock);
3388
3389                         if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
3390                                 /*
3391                                  * Do not put uninitialized extent
3392                                  * in the cache
3393                                  */
3394                                 if (!ext4_ext_is_uninitialized(ex)) {
3395                                         ext4_ext_put_in_cache(inode, ee_block,
3396                                                 ee_len, ee_start);
3397                                         goto out;
3398                                 }
3399                                 ret = ext4_ext_handle_uninitialized_extents(
3400                                         handle, inode, map, path, flags,
3401                                         allocated, newblock);
3402                                 return ret;
3403                         }
3404
3405                         /*
3406                          * Punch out the map length, but only to the
3407                          * end of the extent
3408                          */
3409                         punched_out = allocated < map->m_len ?
3410                                 allocated : map->m_len;
3411
3412                         /*
3413                          * Sense extents need to be converted to
3414                          * uninitialized, they must fit in an
3415                          * uninitialized extent
3416                          */
3417                         if (punched_out > EXT_UNINIT_MAX_LEN)
3418                                 punched_out = EXT_UNINIT_MAX_LEN;
3419
3420                         punch_map.m_lblk = map->m_lblk;
3421                         punch_map.m_pblk = newblock;
3422                         punch_map.m_len = punched_out;
3423                         punch_map.m_flags = 0;
3424
3425                         /* Check to see if the extent needs to be split */
3426                         if (punch_map.m_len != ee_len ||
3427                                 punch_map.m_lblk != ee_block) {
3428
3429                                 ret = ext4_split_extent(handle, inode,
3430                                 path, &punch_map, 0,
3431                                 EXT4_GET_BLOCKS_PUNCH_OUT_EXT |
3432                                 EXT4_GET_BLOCKS_PRE_IO);
3433
3434                                 if (ret < 0) {
3435                                         err = ret;
3436                                         goto out2;
3437                                 }
3438                                 /*
3439                                  * find extent for the block at
3440                                  * the start of the hole
3441                                  */
3442                                 ext4_ext_drop_refs(path);
3443                                 kfree(path);
3444
3445                                 path = ext4_ext_find_extent(inode,
3446                                 map->m_lblk, NULL);
3447                                 if (IS_ERR(path)) {
3448                                         err = PTR_ERR(path);
3449                                         path = NULL;
3450                                         goto out2;
3451                                 }
3452
3453                                 depth = ext_depth(inode);
3454                                 ex = path[depth].p_ext;
3455                                 ee_len = ext4_ext_get_actual_len(ex);
3456                                 ee_block = le32_to_cpu(ex->ee_block);
3457                                 ee_start = ext4_ext_pblock(ex);
3458
3459                         }
3460
3461                         ext4_ext_mark_uninitialized(ex);
3462
3463                         ext4_ext_invalidate_cache(inode);
3464
3465                         err = ext4_ext_rm_leaf(handle, inode, path,
3466                                 map->m_lblk, map->m_lblk + punched_out);
3467
3468                         if (!err && path->p_hdr->eh_entries == 0) {
3469                                 /*
3470                                  * Punch hole freed all of this sub tree,
3471                                  * so we need to correct eh_depth
3472                                  */
3473                                 err = ext4_ext_get_access(handle, inode, path);
3474                                 if (err == 0) {
3475                                         ext_inode_hdr(inode)->eh_depth = 0;
3476                                         ext_inode_hdr(inode)->eh_max =
3477                                         cpu_to_le16(ext4_ext_space_root(
3478                                                 inode, 0));
3479
3480                                         err = ext4_ext_dirty(
3481                                                 handle, inode, path);
3482                                 }
3483                         }
3484
3485                         goto out2;
3486                 }
3487         }
3488
3489         /*
3490          * requested block isn't allocated yet;
3491          * we couldn't try to create block if create flag is zero
3492          */
3493         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3494                 /*
3495                  * put just found gap into cache to speed up
3496                  * subsequent requests
3497                  */
3498                 ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
3499                 goto out2;
3500         }
3501         /*
3502          * Okay, we need to do block allocation.
3503          */
3504
3505         /* find neighbour allocated blocks */
3506         ar.lleft = map->m_lblk;
3507         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
3508         if (err)
3509                 goto out2;
3510         ar.lright = map->m_lblk;
3511         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
3512         if (err)
3513                 goto out2;
3514
3515         /*
3516          * See if request is beyond maximum number of blocks we can have in
3517          * a single extent. For an initialized extent this limit is
3518          * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
3519          * EXT_UNINIT_MAX_LEN.
3520          */
3521         if (map->m_len > EXT_INIT_MAX_LEN &&
3522             !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3523                 map->m_len = EXT_INIT_MAX_LEN;
3524         else if (map->m_len > EXT_UNINIT_MAX_LEN &&
3525                  (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
3526                 map->m_len = EXT_UNINIT_MAX_LEN;
3527
3528         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
3529         newex.ee_block = cpu_to_le32(map->m_lblk);
3530         newex.ee_len = cpu_to_le16(map->m_len);
3531         err = ext4_ext_check_overlap(inode, &newex, path);
3532         if (err)
3533                 allocated = ext4_ext_get_actual_len(&newex);
3534         else
3535                 allocated = map->m_len;
3536
3537         /* allocate new block */
3538         ar.inode = inode;
3539         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
3540         ar.logical = map->m_lblk;
3541         ar.len = allocated;
3542         if (S_ISREG(inode->i_mode))
3543                 ar.flags = EXT4_MB_HINT_DATA;
3544         else
3545                 /* disable in-core preallocation for non-regular files */
3546                 ar.flags = 0;
3547         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
3548                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
3549         newblock = ext4_mb_new_blocks(handle, &ar, &err);
3550         if (!newblock)
3551                 goto out2;
3552         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
3553                   ar.goal, newblock, allocated);
3554
3555         /* try to insert new extent into found leaf and return */
3556         ext4_ext_store_pblock(&newex, newblock);
3557         newex.ee_len = cpu_to_le16(ar.len);
3558         /* Mark uninitialized */
3559         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
3560                 ext4_ext_mark_uninitialized(&newex);
3561                 /*
3562                  * io_end structure was created for every IO write to an
3563                  * uninitialized extent. To avoid unnecessary conversion,
3564                  * here we flag the IO that really needs the conversion.
3565                  * For non asycn direct IO case, flag the inode state
3566                  * that we need to perform conversion when IO is done.
3567                  */
3568                 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3569                         if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
3570                                 io->flag = EXT4_IO_END_UNWRITTEN;
3571                                 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
3572                         } else
3573                                 ext4_set_inode_state(inode,
3574                                                      EXT4_STATE_DIO_UNWRITTEN);
3575                 }
3576                 if (ext4_should_dioread_nolock(inode))
3577                         map->m_flags |= EXT4_MAP_UNINIT;
3578         }
3579
3580         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
3581         if (!err)
3582                 err = ext4_ext_insert_extent(handle, inode, path,
3583                                              &newex, flags);
3584         if (err) {
3585                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
3586                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
3587                 /* free data blocks we just allocated */
3588                 /* not a good idea to call discard here directly,
3589                  * but otherwise we'd need to call it every free() */
3590                 ext4_discard_preallocations(inode);
3591                 ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
3592                                  ext4_ext_get_actual_len(&newex), fb_flags);
3593                 goto out2;
3594         }
3595
3596         /* previous routine could use block we allocated */
3597         newblock = ext4_ext_pblock(&newex);
3598         allocated = ext4_ext_get_actual_len(&newex);
3599         if (allocated > map->m_len)
3600                 allocated = map->m_len;
3601         map->m_flags |= EXT4_MAP_NEW;
3602
3603         /*
3604          * Update reserved blocks/metadata blocks after successful
3605          * block allocation which had been deferred till now.
3606          */
3607         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
3608                 ext4_da_update_reserve_space(inode, allocated, 1);
3609
3610         /*
3611          * Cache the extent and update transaction to commit on fdatasync only
3612          * when it is _not_ an uninitialized extent.
3613          */
3614         if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
3615                 ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
3616                 ext4_update_inode_fsync_trans(handle, inode, 1);
3617         } else
3618                 ext4_update_inode_fsync_trans(handle, inode, 0);
3619 out:
3620         if (allocated > map->m_len)
3621                 allocated = map->m_len;
3622         ext4_ext_show_leaf(inode, path);
3623         map->m_flags |= EXT4_MAP_MAPPED;
3624         map->m_pblk = newblock;
3625         map->m_len = allocated;
3626 out2:
3627         if (path) {
3628                 ext4_ext_drop_refs(path);
3629                 kfree(path);
3630         }
3631         trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
3632                 newblock, map->m_len, err ? err : allocated);
3633
3634         result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
3635                         punched_out : allocated;
3636
3637         return err ? err : result;
3638 }
3639
3640 void ext4_ext_truncate(struct inode *inode)
3641 {
3642         struct address_space *mapping = inode->i_mapping;
3643         struct super_block *sb = inode->i_sb;
3644         ext4_lblk_t last_block;
3645         handle_t *handle;
3646         int err = 0;
3647
3648         /*
3649          * finish any pending end_io work so we won't run the risk of
3650          * converting any truncated blocks to initialized later
3651          */
3652         ext4_flush_completed_IO(inode);
3653
3654         /*
3655          * probably first extent we're gonna free will be last in block
3656          */
3657         err = ext4_writepage_trans_blocks(inode);
3658         handle = ext4_journal_start(inode, err);
3659         if (IS_ERR(handle))
3660                 return;
3661
3662         if (inode->i_size & (sb->s_blocksize - 1))
3663                 ext4_block_truncate_page(handle, mapping, inode->i_size);
3664
3665         if (ext4_orphan_add(handle, inode))
3666                 goto out_stop;
3667
3668         down_write(&EXT4_I(inode)->i_data_sem);
3669         ext4_ext_invalidate_cache(inode);
3670
3671         ext4_discard_preallocations(inode);
3672
3673         /*
3674          * TODO: optimization is possible here.
3675          * Probably we need not scan at all,
3676          * because page truncation is enough.
3677          */
3678
3679         /* we have to know where to truncate from in crash case */
3680         EXT4_I(inode)->i_disksize = inode->i_size;
3681         ext4_mark_inode_dirty(handle, inode);
3682
3683         last_block = (inode->i_size + sb->s_blocksize - 1)
3684                         >> EXT4_BLOCK_SIZE_BITS(sb);
3685         err = ext4_ext_remove_space(inode, last_block);
3686
3687         /* In a multi-transaction truncate, we only make the final
3688          * transaction synchronous.
3689          */
3690         if (IS_SYNC(inode))
3691                 ext4_handle_sync(handle);
3692
3693         up_write(&EXT4_I(inode)->i_data_sem);
3694
3695 out_stop:
3696         /*
3697          * If this was a simple ftruncate() and the file will remain alive,
3698          * then we need to clear up the orphan record which we created above.
3699          * However, if this was a real unlink then we were called by
3700          * ext4_delete_inode(), and we allow that function to clean up the
3701          * orphan info for us.
3702          */
3703         if (inode->i_nlink)
3704                 ext4_orphan_del(handle, inode);
3705
3706         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3707         ext4_mark_inode_dirty(handle, inode);
3708         ext4_journal_stop(handle);
3709 }
3710
3711 static void ext4_falloc_update_inode(struct inode *inode,
3712                                 int mode, loff_t new_size, int update_ctime)
3713 {
3714         struct timespec now;
3715
3716         if (update_ctime) {
3717                 now = current_fs_time(inode->i_sb);
3718                 if (!timespec_equal(&inode->i_ctime, &now))
3719                         inode->i_ctime = now;
3720         }
3721         /*
3722          * Update only when preallocation was requested beyond
3723          * the file size.
3724          */
3725         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3726                 if (new_size > i_size_read(inode))
3727                         i_size_write(inode, new_size);
3728                 if (new_size > EXT4_I(inode)->i_disksize)
3729                         ext4_update_i_disksize(inode, new_size);
3730         } else {
3731                 /*
3732                  * Mark that we allocate beyond EOF so the subsequent truncate
3733                  * can proceed even if the new size is the same as i_size.
3734                  */
3735                 if (new_size > i_size_read(inode))
3736                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3737         }
3738
3739 }
3740
3741 /*
3742  * preallocate space for a file. This implements ext4's fallocate file
3743  * operation, which gets called from sys_fallocate system call.
3744  * For block-mapped files, posix_fallocate should fall back to the method
3745  * of writing zeroes to the required new blocks (the same behavior which is
3746  * expected for file systems which do not support fallocate() system call).
3747  */
3748 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
3749 {
3750         struct inode *inode = file->f_path.dentry->d_inode;
3751         handle_t *handle;
3752         loff_t new_size;
3753         unsigned int max_blocks;
3754         int ret = 0;
3755         int ret2 = 0;
3756         int retries = 0;
3757         struct ext4_map_blocks map;
3758         unsigned int credits, blkbits = inode->i_blkbits;
3759
3760         /*
3761          * currently supporting (pre)allocate mode for extent-based
3762          * files _only_
3763          */
3764         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
3765                 return -EOPNOTSUPP;
3766
3767         /* Return error if mode is not supported */
3768         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
3769                 return -EOPNOTSUPP;
3770
3771         if (mode & FALLOC_FL_PUNCH_HOLE)
3772                 return ext4_punch_hole(file, offset, len);
3773
3774         trace_ext4_fallocate_enter(inode, offset, len, mode);
3775         map.m_lblk = offset >> blkbits;
3776         /*
3777          * We can't just convert len to max_blocks because
3778          * If blocksize = 4096 offset = 3072 and len = 2048
3779          */
3780         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
3781                 - map.m_lblk;
3782         /*
3783          * credits to insert 1 extent into extent tree
3784          */
3785         credits = ext4_chunk_trans_blocks(inode, max_blocks);
3786         mutex_lock(&inode->i_mutex);
3787         ret = inode_newsize_ok(inode, (len + offset));
3788         if (ret) {
3789                 mutex_unlock(&inode->i_mutex);
3790                 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
3791                 return ret;
3792         }
3793 retry:
3794         while (ret >= 0 && ret < max_blocks) {
3795                 map.m_lblk = map.m_lblk + ret;
3796                 map.m_len = max_blocks = max_blocks - ret;
3797                 handle = ext4_journal_start(inode, credits);
3798                 if (IS_ERR(handle)) {
3799                         ret = PTR_ERR(handle);
3800                         break;
3801                 }
3802                 ret = ext4_map_blocks(handle, inode, &map,
3803                                       EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
3804                                       EXT4_GET_BLOCKS_NO_NORMALIZE);
3805                 if (ret <= 0) {
3806 #ifdef EXT4FS_DEBUG
3807                         WARN_ON(ret <= 0);
3808                         printk(KERN_ERR "%s: ext4_ext_map_blocks "
3809                                     "returned error inode#%lu, block=%u, "
3810                                     "max_blocks=%u", __func__,
3811                                     inode->i_ino, map.m_lblk, max_blocks);
3812 #endif
3813                         ext4_mark_inode_dirty(handle, inode);
3814                         ret2 = ext4_journal_stop(handle);
3815                         break;
3816                 }
3817                 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
3818                                                 blkbits) >> blkbits))
3819                         new_size = offset + len;
3820                 else
3821                         new_size = (map.m_lblk + ret) << blkbits;
3822
3823                 ext4_falloc_update_inode(inode, mode, new_size,
3824                                          (map.m_flags & EXT4_MAP_NEW));
3825                 ext4_mark_inode_dirty(handle, inode);
3826                 ret2 = ext4_journal_stop(handle);
3827                 if (ret2)
3828                         break;
3829         }
3830         if (ret == -ENOSPC &&
3831                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
3832                 ret = 0;
3833                 goto retry;
3834         }
3835         mutex_unlock(&inode->i_mutex);
3836         trace_ext4_fallocate_exit(inode, offset, max_blocks,
3837                                 ret > 0 ? ret2 : ret);
3838         return ret > 0 ? ret2 : ret;
3839 }
3840
3841 /*
3842  * This function convert a range of blocks to written extents
3843  * The caller of this function will pass the start offset and the size.
3844  * all unwritten extents within this range will be converted to
3845  * written extents.
3846  *
3847  * This function is called from the direct IO end io call back
3848  * function, to convert the fallocated extents after IO is completed.
3849  * Returns 0 on success.
3850  */
3851 int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
3852                                     ssize_t len)
3853 {
3854         handle_t *handle;
3855         unsigned int max_blocks;
3856         int ret = 0;
3857         int ret2 = 0;
3858         struct ext4_map_blocks map;
3859         unsigned int credits, blkbits = inode->i_blkbits;
3860
3861         map.m_lblk = offset >> blkbits;
3862         /*
3863          * We can't just convert len to max_blocks because
3864          * If blocksize = 4096 offset = 3072 and len = 2048
3865          */
3866         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
3867                       map.m_lblk);
3868         /*
3869          * credits to insert 1 extent into extent tree
3870          */
3871         credits = ext4_chunk_trans_blocks(inode, max_blocks);
3872         while (ret >= 0 && ret < max_blocks) {
3873                 map.m_lblk += ret;
3874                 map.m_len = (max_blocks -= ret);
3875                 handle = ext4_journal_start(inode, credits);
3876                 if (IS_ERR(handle)) {
3877                         ret = PTR_ERR(handle);
3878                         break;
3879                 }
3880                 ret = ext4_map_blocks(handle, inode, &map,
3881                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
3882                 if (ret <= 0) {
3883                         WARN_ON(ret <= 0);
3884                         printk(KERN_ERR "%s: ext4_ext_map_blocks "
3885                                     "returned error inode#%lu, block=%u, "
3886                                     "max_blocks=%u", __func__,
3887                                     inode->i_ino, map.m_lblk, map.m_len);
3888                 }
3889                 ext4_mark_inode_dirty(handle, inode);
3890                 ret2 = ext4_journal_stop(handle);
3891                 if (ret <= 0 || ret2 )
3892                         break;
3893         }
3894         return ret > 0 ? ret2 : ret;
3895 }
3896
3897 /*
3898  * Callback function called for each extent to gather FIEMAP information.
3899  */
3900 static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next,
3901                        struct ext4_ext_cache *newex, struct ext4_extent *ex,
3902                        void *data)
3903 {
3904         __u64   logical;
3905         __u64   physical;
3906         __u64   length;
3907         __u32   flags = 0;
3908         int             ret = 0;
3909         struct fiemap_extent_info *fieinfo = data;
3910         unsigned char blksize_bits;
3911
3912         blksize_bits = inode->i_sb->s_blocksize_bits;
3913         logical = (__u64)newex->ec_block << blksize_bits;
3914
3915         if (newex->ec_start == 0) {
3916                 /*
3917                  * No extent in extent-tree contains block @newex->ec_start,
3918                  * then the block may stay in 1)a hole or 2)delayed-extent.
3919                  *
3920                  * Holes or delayed-extents are processed as follows.
3921                  * 1. lookup dirty pages with specified range in pagecache.
3922                  *    If no page is got, then there is no delayed-extent and
3923                  *    return with EXT_CONTINUE.
3924                  * 2. find the 1st mapped buffer,
3925                  * 3. check if the mapped buffer is both in the request range
3926                  *    and a delayed buffer. If not, there is no delayed-extent,
3927                  *    then return.
3928                  * 4. a delayed-extent is found, the extent will be collected.
3929                  */
3930                 ext4_lblk_t     end = 0;
3931                 pgoff_t         last_offset;
3932                 pgoff_t         offset;
3933                 pgoff_t         index;
3934                 pgoff_t         start_index = 0;
3935                 struct page     **pages = NULL;
3936                 struct buffer_head *bh = NULL;
3937                 struct buffer_head *head = NULL;
3938                 unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
3939
3940                 pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
3941                 if (pages == NULL)
3942                         return -ENOMEM;
3943
3944                 offset = logical >> PAGE_SHIFT;
3945 repeat:
3946                 last_offset = offset;
3947                 head = NULL;
3948                 ret = find_get_pages_tag(inode->i_mapping, &offset,
3949                                         PAGECACHE_TAG_DIRTY, nr_pages, pages);
3950
3951                 if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
3952                         /* First time, try to find a mapped buffer. */
3953                         if (ret == 0) {
3954 out:
3955                                 for (index = 0; index < ret; index++)
3956                                         page_cache_release(pages[index]);
3957                                 /* just a hole. */
3958                                 kfree(pages);
3959                                 return EXT_CONTINUE;
3960                         }
3961                         index = 0;
3962
3963 next_page:
3964                         /* Try to find the 1st mapped buffer. */
3965                         end = ((__u64)pages[index]->index << PAGE_SHIFT) >>
3966                                   blksize_bits;
3967                         if (!page_has_buffers(pages[index]))
3968                                 goto out;
3969                         head = page_buffers(pages[index]);
3970                         if (!head)
3971                                 goto out;
3972
3973                         index++;
3974                         bh = head;
3975                         do {
3976                                 if (end >= newex->ec_block +
3977                                         newex->ec_len)
3978                                         /* The buffer is out of
3979                                          * the request range.
3980                                          */
3981                                         goto out;
3982
3983                                 if (buffer_mapped(bh) &&
3984                                     end >= newex->ec_block) {
3985                                         start_index = index - 1;
3986                                         /* get the 1st mapped buffer. */
3987                                         goto found_mapped_buffer;
3988                                 }
3989
3990                                 bh = bh->b_this_page;
3991                                 end++;
3992                         } while (bh != head);
3993
3994                         /* No mapped buffer in the range found in this page,
3995                          * We need to look up next page.
3996                          */
3997                         if (index >= ret) {
3998                                 /* There is no page left, but we need to limit
3999                                  * newex->ec_len.
4000                                  */
4001                                 newex->ec_len = end - newex->ec_block;
4002                                 goto out;
4003                         }
4004                         goto next_page;
4005                 } else {
4006                         /*Find contiguous delayed buffers. */
4007                         if (ret > 0 && pages[0]->index == last_offset)
4008                                 head = page_buffers(pages[0]);
4009                         bh = head;
4010                         index = 1;
4011                         start_index = 0;
4012                 }
4013
4014 found_mapped_buffer:
4015                 if (bh != NULL && buffer_delay(bh)) {
4016                         /* 1st or contiguous delayed buffer found. */
4017                         if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
4018                                 /*
4019                                  * 1st delayed buffer found, record
4020                                  * the start of extent.
4021                                  */
4022                                 flags |= FIEMAP_EXTENT_DELALLOC;
4023                                 newex->ec_block = end;
4024                                 logical = (__u64)end << blksize_bits;
4025                         }
4026                         /* Find contiguous delayed buffers. */
4027                         do {
4028                                 if (!buffer_delay(bh))
4029                                         goto found_delayed_extent;
4030                                 bh = bh->b_this_page;
4031                                 end++;
4032                         } while (bh != head);
4033
4034                         for (; index < ret; index++) {
4035                                 if (!page_has_buffers(pages[index])) {
4036                                         bh = NULL;
4037                                         break;
4038                                 }
4039                                 head = page_buffers(pages[index]);
4040                                 if (!head) {
4041                                         bh = NULL;
4042                                         break;
4043                                 }
4044
4045                                 if (pages[index]->index !=
4046                                     pages[start_index]->index + index
4047                                     - start_index) {
4048                                         /* Blocks are not contiguous. */
4049                                         bh = NULL;
4050                                         break;
4051                                 }
4052                                 bh = head;
4053                                 do {
4054                                         if (!buffer_delay(bh))
4055                                                 /* Delayed-extent ends. */
4056                                                 goto found_delayed_extent;
4057                                         bh = bh->b_this_page;
4058                                         end++;
4059                                 } while (bh != head);
4060                         }
4061                 } else if (!(flags & FIEMAP_EXTENT_DELALLOC))
4062                         /* a hole found. */
4063                         goto out;
4064
4065 found_delayed_extent:
4066                 newex->ec_len = min(end - newex->ec_block,
4067                                                 (ext4_lblk_t)EXT_INIT_MAX_LEN);
4068                 if (ret == nr_pages && bh != NULL &&
4069                         newex->ec_len < EXT_INIT_MAX_LEN &&
4070                         buffer_delay(bh)) {
4071                         /* Have not collected an extent and continue. */
4072                         for (index = 0; index < ret; index++)
4073                                 page_cache_release(pages[index]);
4074                         goto repeat;
4075                 }
4076
4077                 for (index = 0; index < ret; index++)
4078                         page_cache_release(pages[index]);
4079                 kfree(pages);
4080         }
4081
4082         physical = (__u64)newex->ec_start << blksize_bits;
4083         length =   (__u64)newex->ec_len << blksize_bits;
4084
4085         if (ex && ext4_ext_is_uninitialized(ex))
4086                 flags |= FIEMAP_EXTENT_UNWRITTEN;
4087
4088         if (next == EXT_MAX_BLOCKS)
4089                 flags |= FIEMAP_EXTENT_LAST;
4090
4091         ret = fiemap_fill_next_extent(fieinfo, logical, physical,
4092                                         length, flags);
4093         if (ret < 0)
4094                 return ret;
4095         if (ret == 1)
4096                 return EXT_BREAK;
4097         return EXT_CONTINUE;
4098 }
4099
4100 /* fiemap flags we can handle specified here */
4101 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4102
4103 static int ext4_xattr_fiemap(struct inode *inode,
4104                                 struct fiemap_extent_info *fieinfo)
4105 {
4106         __u64 physical = 0;
4107         __u64 length;
4108         __u32 flags = FIEMAP_EXTENT_LAST;
4109         int blockbits = inode->i_sb->s_blocksize_bits;
4110         int error = 0;
4111
4112         /* in-inode? */
4113         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4114                 struct ext4_iloc iloc;
4115                 int offset;     /* offset of xattr in inode */
4116
4117                 error = ext4_get_inode_loc(inode, &iloc);
4118                 if (error)
4119                         return error;
4120                 physical = iloc.bh->b_blocknr << blockbits;
4121                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4122                                 EXT4_I(inode)->i_extra_isize;
4123                 physical += offset;
4124                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4125                 flags |= FIEMAP_EXTENT_DATA_INLINE;
4126                 brelse(iloc.bh);
4127         } else { /* external block */
4128                 physical = EXT4_I(inode)->i_file_acl << blockbits;
4129                 length = inode->i_sb->s_blocksize;
4130         }
4131
4132         if (physical)
4133                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4134                                                 length, flags);
4135         return (error < 0 ? error : 0);
4136 }
4137
4138 /*
4139  * ext4_ext_punch_hole
4140  *
4141  * Punches a hole of "length" bytes in a file starting
4142  * at byte "offset"
4143  *
4144  * @inode:  The inode of the file to punch a hole in
4145  * @offset: The starting byte offset of the hole
4146  * @length: The length of the hole
4147  *
4148  * Returns the number of blocks removed or negative on err
4149  */
4150 int ext4_ext_punch_hole(struct file *file, loff_t offset, loff_t length)
4151 {
4152         struct inode *inode = file->f_path.dentry->d_inode;
4153         struct super_block *sb = inode->i_sb;
4154         struct ext4_ext_cache cache_ex;
4155         ext4_lblk_t first_block, last_block, num_blocks, iblock, max_blocks;
4156         struct address_space *mapping = inode->i_mapping;
4157         struct ext4_map_blocks map;
4158         handle_t *handle;
4159         loff_t first_block_offset, last_block_offset, block_len;
4160         loff_t first_page, last_page, first_page_offset, last_page_offset;
4161         int ret, credits, blocks_released, err = 0;
4162
4163         first_block = (offset + sb->s_blocksize - 1) >>
4164                 EXT4_BLOCK_SIZE_BITS(sb);
4165         last_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4166
4167         first_block_offset = first_block << EXT4_BLOCK_SIZE_BITS(sb);
4168         last_block_offset = last_block << EXT4_BLOCK_SIZE_BITS(sb);
4169
4170         first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
4171         last_page = (offset + length) >> PAGE_CACHE_SHIFT;
4172
4173         first_page_offset = first_page << PAGE_CACHE_SHIFT;
4174         last_page_offset = last_page << PAGE_CACHE_SHIFT;
4175
4176         /*
4177          * Write out all dirty pages to avoid race conditions
4178          * Then release them.
4179          */
4180         if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4181                 err = filemap_write_and_wait_range(mapping,
4182                         first_page_offset == 0 ? 0 : first_page_offset-1,
4183                         last_page_offset);
4184
4185                         if (err)
4186                                 return err;
4187         }
4188
4189         /* Now release the pages */
4190         if (last_page_offset > first_page_offset) {
4191                 truncate_inode_pages_range(mapping, first_page_offset,
4192                                            last_page_offset-1);
4193         }
4194
4195         /* finish any pending end_io work */
4196         ext4_flush_completed_IO(inode);
4197
4198         credits = ext4_writepage_trans_blocks(inode);
4199         handle = ext4_journal_start(inode, credits);
4200         if (IS_ERR(handle))
4201                 return PTR_ERR(handle);
4202
4203         err = ext4_orphan_add(handle, inode);
4204         if (err)
4205                 goto out;
4206
4207         /*
4208          * Now we need to zero out the un block aligned data.
4209          * If the file is smaller than a block, just
4210          * zero out the middle
4211          */
4212         if (first_block > last_block)
4213                 ext4_block_zero_page_range(handle, mapping, offset, length);
4214         else {
4215                 /* zero out the head of the hole before the first block */
4216                 block_len  = first_block_offset - offset;
4217                 if (block_len > 0)
4218                         ext4_block_zero_page_range(handle, mapping,
4219                                                    offset, block_len);
4220
4221                 /* zero out the tail of the hole after the last block */
4222                 block_len = offset + length - last_block_offset;
4223                 if (block_len > 0) {
4224                         ext4_block_zero_page_range(handle, mapping,
4225                                         last_block_offset, block_len);
4226                 }
4227         }
4228
4229         /* If there are no blocks to remove, return now */
4230         if (first_block >= last_block)
4231                 goto out;
4232
4233         down_write(&EXT4_I(inode)->i_data_sem);
4234         ext4_ext_invalidate_cache(inode);
4235         ext4_discard_preallocations(inode);
4236
4237         /*
4238          * Loop over all the blocks and identify blocks
4239          * that need to be punched out
4240          */
4241         iblock = first_block;
4242         blocks_released = 0;
4243         while (iblock < last_block) {
4244                 max_blocks = last_block - iblock;
4245                 num_blocks = 1;
4246                 memset(&map, 0, sizeof(map));
4247                 map.m_lblk = iblock;
4248                 map.m_len = max_blocks;
4249                 ret = ext4_ext_map_blocks(handle, inode, &map,
4250                         EXT4_GET_BLOCKS_PUNCH_OUT_EXT);
4251
4252                 if (ret > 0) {
4253                         blocks_released += ret;
4254                         num_blocks = ret;
4255                 } else if (ret == 0) {
4256                         /*
4257                          * If map blocks could not find the block,
4258                          * then it is in a hole.  If the hole was
4259                          * not already cached, then map blocks should
4260                          * put it in the cache.  So we can get the hole
4261                          * out of the cache
4262                          */
4263                         memset(&cache_ex, 0, sizeof(cache_ex));
4264                         if ((ext4_ext_check_cache(inode, iblock, &cache_ex)) &&
4265                                 !cache_ex.ec_start) {
4266
4267                                 /* The hole is cached */
4268                                 num_blocks = cache_ex.ec_block +
4269                                 cache_ex.ec_len - iblock;
4270
4271                         } else {
4272                                 /* The block could not be identified */
4273                                 err = -EIO;
4274                                 break;
4275                         }
4276                 } else {
4277                         /* Map blocks error */
4278                         err = ret;
4279                         break;
4280                 }
4281
4282                 if (num_blocks == 0) {
4283                         /* This condition should never happen */
4284                         ext_debug("Block lookup failed");
4285                         err = -EIO;
4286                         break;
4287                 }
4288
4289                 iblock += num_blocks;
4290         }
4291
4292         if (blocks_released > 0) {
4293                 ext4_ext_invalidate_cache(inode);
4294                 ext4_discard_preallocations(inode);
4295         }
4296
4297         if (IS_SYNC(inode))
4298                 ext4_handle_sync(handle);
4299
4300         up_write(&EXT4_I(inode)->i_data_sem);
4301
4302 out:
4303         ext4_orphan_del(handle, inode);
4304         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4305         ext4_mark_inode_dirty(handle, inode);
4306         ext4_journal_stop(handle);
4307         return err;
4308 }
4309 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4310                 __u64 start, __u64 len)
4311 {
4312         ext4_lblk_t start_blk;
4313         int error = 0;
4314
4315         /* fallback to generic here if not in extents fmt */
4316         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4317                 return generic_block_fiemap(inode, fieinfo, start, len,
4318                         ext4_get_block);
4319
4320         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4321                 return -EBADR;
4322
4323         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4324                 error = ext4_xattr_fiemap(inode, fieinfo);
4325         } else {
4326                 ext4_lblk_t len_blks;
4327                 __u64 last_blk;
4328
4329                 start_blk = start >> inode->i_sb->s_blocksize_bits;
4330                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4331                 if (last_blk >= EXT_MAX_BLOCKS)
4332                         last_blk = EXT_MAX_BLOCKS-1;
4333                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4334
4335                 /*
4336                  * Walk the extent tree gathering extent information.
4337                  * ext4_ext_fiemap_cb will push extents back to user.
4338                  */
4339                 error = ext4_ext_walk_space(inode, start_blk, len_blks,
4340                                           ext4_ext_fiemap_cb, fieinfo);
4341         }
4342
4343         return error;
4344 }