[PATCH] ext4: if expression format
[firefly-linux-kernel-4.4.55.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/ext4_jbd2.h>
36 #include <linux/jbd.h>
37 #include <linux/smp_lock.h>
38 #include <linux/highuid.h>
39 #include <linux/pagemap.h>
40 #include <linux/quotaops.h>
41 #include <linux/string.h>
42 #include <linux/slab.h>
43 #include <linux/ext4_fs_extents.h>
44 #include <asm/uaccess.h>
45
46
47 /*
48  * ext_pblock:
49  * combine low and high parts of physical block number into ext4_fsblk_t
50  */
51 static inline ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
52 {
53         ext4_fsblk_t block;
54
55         block = le32_to_cpu(ex->ee_start);
56         block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
57         return block;
58 }
59
60 /*
61  * idx_pblock:
62  * combine low and high parts of a leaf physical block number into ext4_fsblk_t
63  */
64 static inline ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
65 {
66         ext4_fsblk_t block;
67
68         block = le32_to_cpu(ix->ei_leaf);
69         block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
70         return block;
71 }
72
73 /*
74  * ext4_ext_store_pblock:
75  * stores a large physical block number into an extent struct,
76  * breaking it into parts
77  */
78 static inline void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
79 {
80         ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff));
81         ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
82 }
83
84 /*
85  * ext4_idx_store_pblock:
86  * stores a large physical block number into an index struct,
87  * breaking it into parts
88  */
89 static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
90 {
91         ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff));
92         ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
93 }
94
95 static int ext4_ext_check_header(const char *function, struct inode *inode,
96                                 struct ext4_extent_header *eh)
97 {
98         const char *error_msg = NULL;
99
100         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
101                 error_msg = "invalid magic";
102                 goto corrupted;
103         }
104         if (unlikely(eh->eh_max == 0)) {
105                 error_msg = "invalid eh_max";
106                 goto corrupted;
107         }
108         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
109                 error_msg = "invalid eh_entries";
110                 goto corrupted;
111         }
112         return 0;
113
114 corrupted:
115         ext4_error(inode->i_sb, function,
116                         "bad header in inode #%lu: %s - magic %x, "
117                         "entries %u, max %u, depth %u",
118                         inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
119                         le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
120                         le16_to_cpu(eh->eh_depth));
121
122         return -EIO;
123 }
124
125 static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
126 {
127         int err;
128
129         if (handle->h_buffer_credits > needed)
130                 return handle;
131         if (!ext4_journal_extend(handle, needed))
132                 return handle;
133         err = ext4_journal_restart(handle, needed);
134
135         return handle;
136 }
137
138 /*
139  * could return:
140  *  - EROFS
141  *  - ENOMEM
142  */
143 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
144                                 struct ext4_ext_path *path)
145 {
146         if (path->p_bh) {
147                 /* path points to block */
148                 return ext4_journal_get_write_access(handle, path->p_bh);
149         }
150         /* path points to leaf/index in inode body */
151         /* we use in-core data, no need to protect them */
152         return 0;
153 }
154
155 /*
156  * could return:
157  *  - EROFS
158  *  - ENOMEM
159  *  - EIO
160  */
161 static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
162                                 struct ext4_ext_path *path)
163 {
164         int err;
165         if (path->p_bh) {
166                 /* path points to block */
167                 err = ext4_journal_dirty_metadata(handle, path->p_bh);
168         } else {
169                 /* path points to leaf/index in inode body */
170                 err = ext4_mark_inode_dirty(handle, inode);
171         }
172         return err;
173 }
174
175 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
176                               struct ext4_ext_path *path,
177                               ext4_fsblk_t block)
178 {
179         struct ext4_inode_info *ei = EXT4_I(inode);
180         ext4_fsblk_t bg_start;
181         ext4_grpblk_t colour;
182         int depth;
183
184         if (path) {
185                 struct ext4_extent *ex;
186                 depth = path->p_depth;
187
188                 /* try to predict block placement */
189                 ex = path[depth].p_ext;
190                 if (ex)
191                         return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
192
193                 /* it looks like index is empty;
194                  * try to find starting block from index itself */
195                 if (path[depth].p_bh)
196                         return path[depth].p_bh->b_blocknr;
197         }
198
199         /* OK. use inode's group */
200         bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
201                 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
202         colour = (current->pid % 16) *
203                         (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
204         return bg_start + colour + block;
205 }
206
207 static ext4_fsblk_t
208 ext4_ext_new_block(handle_t *handle, struct inode *inode,
209                         struct ext4_ext_path *path,
210                         struct ext4_extent *ex, int *err)
211 {
212         ext4_fsblk_t goal, newblock;
213
214         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
215         newblock = ext4_new_block(handle, inode, goal, err);
216         return newblock;
217 }
218
219 static inline int ext4_ext_space_block(struct inode *inode)
220 {
221         int size;
222
223         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
224                         / sizeof(struct ext4_extent);
225 #ifdef AGRESSIVE_TEST
226         if (size > 6)
227                 size = 6;
228 #endif
229         return size;
230 }
231
232 static inline int ext4_ext_space_block_idx(struct inode *inode)
233 {
234         int size;
235
236         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
237                         / sizeof(struct ext4_extent_idx);
238 #ifdef AGRESSIVE_TEST
239         if (size > 5)
240                 size = 5;
241 #endif
242         return size;
243 }
244
245 static inline int ext4_ext_space_root(struct inode *inode)
246 {
247         int size;
248
249         size = sizeof(EXT4_I(inode)->i_data);
250         size -= sizeof(struct ext4_extent_header);
251         size /= sizeof(struct ext4_extent);
252 #ifdef AGRESSIVE_TEST
253         if (size > 3)
254                 size = 3;
255 #endif
256         return size;
257 }
258
259 static inline int ext4_ext_space_root_idx(struct inode *inode)
260 {
261         int size;
262
263         size = sizeof(EXT4_I(inode)->i_data);
264         size -= sizeof(struct ext4_extent_header);
265         size /= sizeof(struct ext4_extent_idx);
266 #ifdef AGRESSIVE_TEST
267         if (size > 4)
268                 size = 4;
269 #endif
270         return size;
271 }
272
273 #ifdef EXT_DEBUG
274 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
275 {
276         int k, l = path->p_depth;
277
278         ext_debug("path:");
279         for (k = 0; k <= l; k++, path++) {
280                 if (path->p_idx) {
281                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
282                             idx_pblock(path->p_idx));
283                 } else if (path->p_ext) {
284                         ext_debug("  %d:%d:%llu ",
285                                   le32_to_cpu(path->p_ext->ee_block),
286                                   le16_to_cpu(path->p_ext->ee_len),
287                                   ext_pblock(path->p_ext));
288                 } else
289                         ext_debug("  []");
290         }
291         ext_debug("\n");
292 }
293
294 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
295 {
296         int depth = ext_depth(inode);
297         struct ext4_extent_header *eh;
298         struct ext4_extent *ex;
299         int i;
300
301         if (!path)
302                 return;
303
304         eh = path[depth].p_hdr;
305         ex = EXT_FIRST_EXTENT(eh);
306
307         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
308                 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
309                           le16_to_cpu(ex->ee_len), ext_pblock(ex));
310         }
311         ext_debug("\n");
312 }
313 #else
314 #define ext4_ext_show_path(inode,path)
315 #define ext4_ext_show_leaf(inode,path)
316 #endif
317
318 static void ext4_ext_drop_refs(struct ext4_ext_path *path)
319 {
320         int depth = path->p_depth;
321         int i;
322
323         for (i = 0; i <= depth; i++, path++)
324                 if (path->p_bh) {
325                         brelse(path->p_bh);
326                         path->p_bh = NULL;
327                 }
328 }
329
330 /*
331  * ext4_ext_binsearch_idx:
332  * binary search for the closest index of the given block
333  */
334 static void
335 ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
336 {
337         struct ext4_extent_header *eh = path->p_hdr;
338         struct ext4_extent_idx *r, *l, *m;
339
340         BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
341         BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
342         BUG_ON(le16_to_cpu(eh->eh_entries) <= 0);
343
344         ext_debug("binsearch for %d(idx):  ", block);
345
346         l = EXT_FIRST_INDEX(eh) + 1;
347         r = EXT_FIRST_INDEX(eh) + le16_to_cpu(eh->eh_entries) - 1;
348         while (l <= r) {
349                 m = l + (r - l) / 2;
350                 if (block < le32_to_cpu(m->ei_block))
351                         r = m - 1;
352                 else
353                         l = m + 1;
354                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ei_block,
355                                 m, m->ei_block, r, r->ei_block);
356         }
357
358         path->p_idx = l - 1;
359         ext_debug("  -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
360                   idx_block(path->p_idx));
361
362 #ifdef CHECK_BINSEARCH
363         {
364                 struct ext4_extent_idx *chix, *ix;
365                 int k;
366
367                 chix = ix = EXT_FIRST_INDEX(eh);
368                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
369                   if (k != 0 &&
370                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
371                                 printk("k=%d, ix=0x%p, first=0x%p\n", k,
372                                         ix, EXT_FIRST_INDEX(eh));
373                                 printk("%u <= %u\n",
374                                        le32_to_cpu(ix->ei_block),
375                                        le32_to_cpu(ix[-1].ei_block));
376                         }
377                         BUG_ON(k && le32_to_cpu(ix->ei_block)
378                                            <= le32_to_cpu(ix[-1].ei_block));
379                         if (block < le32_to_cpu(ix->ei_block))
380                                 break;
381                         chix = ix;
382                 }
383                 BUG_ON(chix != path->p_idx);
384         }
385 #endif
386
387 }
388
389 /*
390  * ext4_ext_binsearch:
391  * binary search for closest extent of the given block
392  */
393 static void
394 ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
395 {
396         struct ext4_extent_header *eh = path->p_hdr;
397         struct ext4_extent *r, *l, *m;
398
399         BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
400         BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
401
402         if (eh->eh_entries == 0) {
403                 /*
404                  * this leaf is empty:
405                  * we get such a leaf in split/add case
406                  */
407                 return;
408         }
409
410         ext_debug("binsearch for %d:  ", block);
411
412         l = EXT_FIRST_EXTENT(eh) + 1;
413         r = EXT_FIRST_EXTENT(eh) + le16_to_cpu(eh->eh_entries) - 1;
414
415         while (l <= r) {
416                 m = l + (r - l) / 2;
417                 if (block < le32_to_cpu(m->ee_block))
418                         r = m - 1;
419                 else
420                         l = m + 1;
421                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ee_block,
422                                 m, m->ee_block, r, r->ee_block);
423         }
424
425         path->p_ext = l - 1;
426         ext_debug("  -> %d:%llu:%d ",
427                         le32_to_cpu(path->p_ext->ee_block),
428                         ext_pblock(path->p_ext),
429                         le16_to_cpu(path->p_ext->ee_len));
430
431 #ifdef CHECK_BINSEARCH
432         {
433                 struct ext4_extent *chex, *ex;
434                 int k;
435
436                 chex = ex = EXT_FIRST_EXTENT(eh);
437                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
438                         BUG_ON(k && le32_to_cpu(ex->ee_block)
439                                           <= le32_to_cpu(ex[-1].ee_block));
440                         if (block < le32_to_cpu(ex->ee_block))
441                                 break;
442                         chex = ex;
443                 }
444                 BUG_ON(chex != path->p_ext);
445         }
446 #endif
447
448 }
449
450 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
451 {
452         struct ext4_extent_header *eh;
453
454         eh = ext_inode_hdr(inode);
455         eh->eh_depth = 0;
456         eh->eh_entries = 0;
457         eh->eh_magic = EXT4_EXT_MAGIC;
458         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
459         ext4_mark_inode_dirty(handle, inode);
460         ext4_ext_invalidate_cache(inode);
461         return 0;
462 }
463
464 struct ext4_ext_path *
465 ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
466 {
467         struct ext4_extent_header *eh;
468         struct buffer_head *bh;
469         short int depth, i, ppos = 0, alloc = 0;
470
471         eh = ext_inode_hdr(inode);
472         BUG_ON(eh == NULL);
473         if (ext4_ext_check_header(__FUNCTION__, inode, eh))
474                 return ERR_PTR(-EIO);
475
476         i = depth = ext_depth(inode);
477
478         /* account possible depth increase */
479         if (!path) {
480                 path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 2),
481                                 GFP_NOFS);
482                 if (!path)
483                         return ERR_PTR(-ENOMEM);
484                 alloc = 1;
485         }
486         memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
487         path[0].p_hdr = eh;
488
489         /* walk through the tree */
490         while (i) {
491                 ext_debug("depth %d: num %d, max %d\n",
492                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
493                 ext4_ext_binsearch_idx(inode, path + ppos, block);
494                 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
495                 path[ppos].p_depth = i;
496                 path[ppos].p_ext = NULL;
497
498                 bh = sb_bread(inode->i_sb, path[ppos].p_block);
499                 if (!bh)
500                         goto err;
501
502                 eh = ext_block_hdr(bh);
503                 ppos++;
504                 BUG_ON(ppos > depth);
505                 path[ppos].p_bh = bh;
506                 path[ppos].p_hdr = eh;
507                 i--;
508
509                 if (ext4_ext_check_header(__FUNCTION__, inode, eh))
510                         goto err;
511         }
512
513         path[ppos].p_depth = i;
514         path[ppos].p_hdr = eh;
515         path[ppos].p_ext = NULL;
516         path[ppos].p_idx = NULL;
517
518         if (ext4_ext_check_header(__FUNCTION__, inode, eh))
519                 goto err;
520
521         /* find extent */
522         ext4_ext_binsearch(inode, path + ppos, block);
523
524         ext4_ext_show_path(inode, path);
525
526         return path;
527
528 err:
529         ext4_ext_drop_refs(path);
530         if (alloc)
531                 kfree(path);
532         return ERR_PTR(-EIO);
533 }
534
535 /*
536  * ext4_ext_insert_index:
537  * insert new index [@logical;@ptr] into the block at @curp;
538  * check where to insert: before @curp or after @curp
539  */
540 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
541                                 struct ext4_ext_path *curp,
542                                 int logical, ext4_fsblk_t ptr)
543 {
544         struct ext4_extent_idx *ix;
545         int len, err;
546
547         err = ext4_ext_get_access(handle, inode, curp);
548         if (err)
549                 return err;
550
551         BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
552         len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
553         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
554                 /* insert after */
555                 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
556                         len = (len - 1) * sizeof(struct ext4_extent_idx);
557                         len = len < 0 ? 0 : len;
558                         ext_debug("insert new index %d after: %d. "
559                                         "move %d from 0x%p to 0x%p\n",
560                                         logical, ptr, len,
561                                         (curp->p_idx + 1), (curp->p_idx + 2));
562                         memmove(curp->p_idx + 2, curp->p_idx + 1, len);
563                 }
564                 ix = curp->p_idx + 1;
565         } else {
566                 /* insert before */
567                 len = len * sizeof(struct ext4_extent_idx);
568                 len = len < 0 ? 0 : len;
569                 ext_debug("insert new index %d before: %d. "
570                                 "move %d from 0x%p to 0x%p\n",
571                                 logical, ptr, len,
572                                 curp->p_idx, (curp->p_idx + 1));
573                 memmove(curp->p_idx + 1, curp->p_idx, len);
574                 ix = curp->p_idx;
575         }
576
577         ix->ei_block = cpu_to_le32(logical);
578         ext4_idx_store_pblock(ix, ptr);
579         curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
580
581         BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
582                              > le16_to_cpu(curp->p_hdr->eh_max));
583         BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
584
585         err = ext4_ext_dirty(handle, inode, curp);
586         ext4_std_error(inode->i_sb, err);
587
588         return err;
589 }
590
591 /*
592  * ext4_ext_split:
593  * inserts new subtree into the path, using free index entry
594  * at depth @at:
595  * - allocates all needed blocks (new leaf and all intermediate index blocks)
596  * - makes decision where to split
597  * - moves remaining extents and index entries (right to the split point)
598  *   into the newly allocated blocks
599  * - initializes subtree
600  */
601 static int ext4_ext_split(handle_t *handle, struct inode *inode,
602                                 struct ext4_ext_path *path,
603                                 struct ext4_extent *newext, int at)
604 {
605         struct buffer_head *bh = NULL;
606         int depth = ext_depth(inode);
607         struct ext4_extent_header *neh;
608         struct ext4_extent_idx *fidx;
609         struct ext4_extent *ex;
610         int i = at, k, m, a;
611         ext4_fsblk_t newblock, oldblock;
612         __le32 border;
613         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
614         int err = 0;
615
616         /* make decision: where to split? */
617         /* FIXME: now decision is simplest: at current extent */
618
619         /* if current leaf will be split, then we should use
620          * border from split point */
621         BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
622         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
623                 border = path[depth].p_ext[1].ee_block;
624                 ext_debug("leaf will be split."
625                                 " next leaf starts at %d\n",
626                                   le32_to_cpu(border));
627         } else {
628                 border = newext->ee_block;
629                 ext_debug("leaf will be added."
630                                 " next leaf starts at %d\n",
631                                 le32_to_cpu(border));
632         }
633
634         /*
635          * If error occurs, then we break processing
636          * and mark filesystem read-only. index won't
637          * be inserted and tree will be in consistent
638          * state. Next mount will repair buffers too.
639          */
640
641         /*
642          * Get array to track all allocated blocks.
643          * We need this to handle errors and free blocks
644          * upon them.
645          */
646         ablocks = kmalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
647         if (!ablocks)
648                 return -ENOMEM;
649         memset(ablocks, 0, sizeof(ext4_fsblk_t) * depth);
650
651         /* allocate all needed blocks */
652         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
653         for (a = 0; a < depth - at; a++) {
654                 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
655                 if (newblock == 0)
656                         goto cleanup;
657                 ablocks[a] = newblock;
658         }
659
660         /* initialize new leaf */
661         newblock = ablocks[--a];
662         BUG_ON(newblock == 0);
663         bh = sb_getblk(inode->i_sb, newblock);
664         if (!bh) {
665                 err = -EIO;
666                 goto cleanup;
667         }
668         lock_buffer(bh);
669
670         err = ext4_journal_get_create_access(handle, bh);
671         if (err)
672                 goto cleanup;
673
674         neh = ext_block_hdr(bh);
675         neh->eh_entries = 0;
676         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
677         neh->eh_magic = EXT4_EXT_MAGIC;
678         neh->eh_depth = 0;
679         ex = EXT_FIRST_EXTENT(neh);
680
681         /* move remainder of path[depth] to the new leaf */
682         BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
683         /* start copy from next extent */
684         /* TODO: we could do it by single memmove */
685         m = 0;
686         path[depth].p_ext++;
687         while (path[depth].p_ext <=
688                         EXT_MAX_EXTENT(path[depth].p_hdr)) {
689                 ext_debug("move %d:%llu:%d in new leaf %llu\n",
690                                 le32_to_cpu(path[depth].p_ext->ee_block),
691                                 ext_pblock(path[depth].p_ext),
692                                 le16_to_cpu(path[depth].p_ext->ee_len),
693                                 newblock);
694                 /*memmove(ex++, path[depth].p_ext++,
695                                 sizeof(struct ext4_extent));
696                 neh->eh_entries++;*/
697                 path[depth].p_ext++;
698                 m++;
699         }
700         if (m) {
701                 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
702                 neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
703         }
704
705         set_buffer_uptodate(bh);
706         unlock_buffer(bh);
707
708         err = ext4_journal_dirty_metadata(handle, bh);
709         if (err)
710                 goto cleanup;
711         brelse(bh);
712         bh = NULL;
713
714         /* correct old leaf */
715         if (m) {
716                 err = ext4_ext_get_access(handle, inode, path + depth);
717                 if (err)
718                         goto cleanup;
719                 path[depth].p_hdr->eh_entries =
720                      cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
721                 err = ext4_ext_dirty(handle, inode, path + depth);
722                 if (err)
723                         goto cleanup;
724
725         }
726
727         /* create intermediate indexes */
728         k = depth - at - 1;
729         BUG_ON(k < 0);
730         if (k)
731                 ext_debug("create %d intermediate indices\n", k);
732         /* insert new index into current index block */
733         /* current depth stored in i var */
734         i = depth - 1;
735         while (k--) {
736                 oldblock = newblock;
737                 newblock = ablocks[--a];
738                 bh = sb_getblk(inode->i_sb, (ext4_fsblk_t)newblock);
739                 if (!bh) {
740                         err = -EIO;
741                         goto cleanup;
742                 }
743                 lock_buffer(bh);
744
745                 err = ext4_journal_get_create_access(handle, bh);
746                 if (err)
747                         goto cleanup;
748
749                 neh = ext_block_hdr(bh);
750                 neh->eh_entries = cpu_to_le16(1);
751                 neh->eh_magic = EXT4_EXT_MAGIC;
752                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
753                 neh->eh_depth = cpu_to_le16(depth - i);
754                 fidx = EXT_FIRST_INDEX(neh);
755                 fidx->ei_block = border;
756                 ext4_idx_store_pblock(fidx, oldblock);
757
758                 ext_debug("int.index at %d (block %llu): %lu -> %llu\n", i,
759                                 newblock, (unsigned long) le32_to_cpu(border),
760                                 oldblock);
761                 /* copy indexes */
762                 m = 0;
763                 path[i].p_idx++;
764
765                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
766                                 EXT_MAX_INDEX(path[i].p_hdr));
767                 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
768                                 EXT_LAST_INDEX(path[i].p_hdr));
769                 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
770                         ext_debug("%d: move %d:%d in new index %llu\n", i,
771                                         le32_to_cpu(path[i].p_idx->ei_block),
772                                         idx_pblock(path[i].p_idx),
773                                         newblock);
774                         /*memmove(++fidx, path[i].p_idx++,
775                                         sizeof(struct ext4_extent_idx));
776                         neh->eh_entries++;
777                         BUG_ON(neh->eh_entries > neh->eh_max);*/
778                         path[i].p_idx++;
779                         m++;
780                 }
781                 if (m) {
782                         memmove(++fidx, path[i].p_idx - m,
783                                 sizeof(struct ext4_extent_idx) * m);
784                         neh->eh_entries =
785                                 cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
786                 }
787                 set_buffer_uptodate(bh);
788                 unlock_buffer(bh);
789
790                 err = ext4_journal_dirty_metadata(handle, bh);
791                 if (err)
792                         goto cleanup;
793                 brelse(bh);
794                 bh = NULL;
795
796                 /* correct old index */
797                 if (m) {
798                         err = ext4_ext_get_access(handle, inode, path + i);
799                         if (err)
800                                 goto cleanup;
801                         path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
802                         err = ext4_ext_dirty(handle, inode, path + i);
803                         if (err)
804                                 goto cleanup;
805                 }
806
807                 i--;
808         }
809
810         /* insert new index */
811         err = ext4_ext_insert_index(handle, inode, path + at,
812                                     le32_to_cpu(border), newblock);
813
814 cleanup:
815         if (bh) {
816                 if (buffer_locked(bh))
817                         unlock_buffer(bh);
818                 brelse(bh);
819         }
820
821         if (err) {
822                 /* free all allocated blocks in error case */
823                 for (i = 0; i < depth; i++) {
824                         if (!ablocks[i])
825                                 continue;
826                         ext4_free_blocks(handle, inode, ablocks[i], 1);
827                 }
828         }
829         kfree(ablocks);
830
831         return err;
832 }
833
834 /*
835  * ext4_ext_grow_indepth:
836  * implements tree growing procedure:
837  * - allocates new block
838  * - moves top-level data (index block or leaf) into the new block
839  * - initializes new top-level, creating index that points to the
840  *   just created block
841  */
842 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
843                                         struct ext4_ext_path *path,
844                                         struct ext4_extent *newext)
845 {
846         struct ext4_ext_path *curp = path;
847         struct ext4_extent_header *neh;
848         struct ext4_extent_idx *fidx;
849         struct buffer_head *bh;
850         ext4_fsblk_t newblock;
851         int err = 0;
852
853         newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
854         if (newblock == 0)
855                 return err;
856
857         bh = sb_getblk(inode->i_sb, newblock);
858         if (!bh) {
859                 err = -EIO;
860                 ext4_std_error(inode->i_sb, err);
861                 return err;
862         }
863         lock_buffer(bh);
864
865         err = ext4_journal_get_create_access(handle, bh);
866         if (err) {
867                 unlock_buffer(bh);
868                 goto out;
869         }
870
871         /* move top-level index/leaf into new block */
872         memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
873
874         /* set size of new block */
875         neh = ext_block_hdr(bh);
876         /* old root could have indexes or leaves
877          * so calculate e_max right way */
878         if (ext_depth(inode))
879           neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
880         else
881           neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
882         neh->eh_magic = EXT4_EXT_MAGIC;
883         set_buffer_uptodate(bh);
884         unlock_buffer(bh);
885
886         err = ext4_journal_dirty_metadata(handle, bh);
887         if (err)
888                 goto out;
889
890         /* create index in new top-level index: num,max,pointer */
891         err = ext4_ext_get_access(handle, inode, curp);
892         if (err)
893                 goto out;
894
895         curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
896         curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
897         curp->p_hdr->eh_entries = cpu_to_le16(1);
898         curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
899         /* FIXME: it works, but actually path[0] can be index */
900         curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
901         ext4_idx_store_pblock(curp->p_idx, newblock);
902
903         neh = ext_inode_hdr(inode);
904         fidx = EXT_FIRST_INDEX(neh);
905         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
906                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
907                   le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
908
909         neh->eh_depth = cpu_to_le16(path->p_depth + 1);
910         err = ext4_ext_dirty(handle, inode, curp);
911 out:
912         brelse(bh);
913
914         return err;
915 }
916
917 /*
918  * ext4_ext_create_new_leaf:
919  * finds empty index and adds new leaf.
920  * if no free index is found, then it requests in-depth growing.
921  */
922 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
923                                         struct ext4_ext_path *path,
924                                         struct ext4_extent *newext)
925 {
926         struct ext4_ext_path *curp;
927         int depth, i, err = 0;
928
929 repeat:
930         i = depth = ext_depth(inode);
931
932         /* walk up to the tree and look for free index entry */
933         curp = path + depth;
934         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
935                 i--;
936                 curp--;
937         }
938
939         /* we use already allocated block for index block,
940          * so subsequent data blocks should be contiguous */
941         if (EXT_HAS_FREE_INDEX(curp)) {
942                 /* if we found index with free entry, then use that
943                  * entry: create all needed subtree and add new leaf */
944                 err = ext4_ext_split(handle, inode, path, newext, i);
945
946                 /* refill path */
947                 ext4_ext_drop_refs(path);
948                 path = ext4_ext_find_extent(inode,
949                                             le32_to_cpu(newext->ee_block),
950                                             path);
951                 if (IS_ERR(path))
952                         err = PTR_ERR(path);
953         } else {
954                 /* tree is full, time to grow in depth */
955                 err = ext4_ext_grow_indepth(handle, inode, path, newext);
956                 if (err)
957                         goto out;
958
959                 /* refill path */
960                 ext4_ext_drop_refs(path);
961                 path = ext4_ext_find_extent(inode,
962                                             le32_to_cpu(newext->ee_block),
963                                             path);
964                 if (IS_ERR(path)) {
965                         err = PTR_ERR(path);
966                         goto out;
967                 }
968
969                 /*
970                  * only first (depth 0 -> 1) produces free space;
971                  * in all other cases we have to split the grown tree
972                  */
973                 depth = ext_depth(inode);
974                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
975                         /* now we need to split */
976                         goto repeat;
977                 }
978         }
979
980 out:
981         return err;
982 }
983
984 /*
985  * ext4_ext_next_allocated_block:
986  * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
987  * NOTE: it considers block number from index entry as
988  * allocated block. Thus, index entries have to be consistent
989  * with leaves.
990  */
991 static unsigned long
992 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
993 {
994         int depth;
995
996         BUG_ON(path == NULL);
997         depth = path->p_depth;
998
999         if (depth == 0 && path->p_ext == NULL)
1000                 return EXT_MAX_BLOCK;
1001
1002         while (depth >= 0) {
1003                 if (depth == path->p_depth) {
1004                         /* leaf */
1005                         if (path[depth].p_ext !=
1006                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1007                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1008                 } else {
1009                         /* index */
1010                         if (path[depth].p_idx !=
1011                                         EXT_LAST_INDEX(path[depth].p_hdr))
1012                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1013                 }
1014                 depth--;
1015         }
1016
1017         return EXT_MAX_BLOCK;
1018 }
1019
1020 /*
1021  * ext4_ext_next_leaf_block:
1022  * returns first allocated block from next leaf or EXT_MAX_BLOCK
1023  */
1024 static unsigned ext4_ext_next_leaf_block(struct inode *inode,
1025                                         struct ext4_ext_path *path)
1026 {
1027         int depth;
1028
1029         BUG_ON(path == NULL);
1030         depth = path->p_depth;
1031
1032         /* zero-tree has no leaf blocks at all */
1033         if (depth == 0)
1034                 return EXT_MAX_BLOCK;
1035
1036         /* go to index block */
1037         depth--;
1038
1039         while (depth >= 0) {
1040                 if (path[depth].p_idx !=
1041                                 EXT_LAST_INDEX(path[depth].p_hdr))
1042                   return le32_to_cpu(path[depth].p_idx[1].ei_block);
1043                 depth--;
1044         }
1045
1046         return EXT_MAX_BLOCK;
1047 }
1048
1049 /*
1050  * ext4_ext_correct_indexes:
1051  * if leaf gets modified and modified extent is first in the leaf,
1052  * then we have to correct all indexes above.
1053  * TODO: do we need to correct tree in all cases?
1054  */
1055 int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1056                                 struct ext4_ext_path *path)
1057 {
1058         struct ext4_extent_header *eh;
1059         int depth = ext_depth(inode);
1060         struct ext4_extent *ex;
1061         __le32 border;
1062         int k, err = 0;
1063
1064         eh = path[depth].p_hdr;
1065         ex = path[depth].p_ext;
1066         BUG_ON(ex == NULL);
1067         BUG_ON(eh == NULL);
1068
1069         if (depth == 0) {
1070                 /* there is no tree at all */
1071                 return 0;
1072         }
1073
1074         if (ex != EXT_FIRST_EXTENT(eh)) {
1075                 /* we correct tree if first leaf got modified only */
1076                 return 0;
1077         }
1078
1079         /*
1080          * TODO: we need correction if border is smaller than current one
1081          */
1082         k = depth - 1;
1083         border = path[depth].p_ext->ee_block;
1084         err = ext4_ext_get_access(handle, inode, path + k);
1085         if (err)
1086                 return err;
1087         path[k].p_idx->ei_block = border;
1088         err = ext4_ext_dirty(handle, inode, path + k);
1089         if (err)
1090                 return err;
1091
1092         while (k--) {
1093                 /* change all left-side indexes */
1094                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1095                         break;
1096                 err = ext4_ext_get_access(handle, inode, path + k);
1097                 if (err)
1098                         break;
1099                 path[k].p_idx->ei_block = border;
1100                 err = ext4_ext_dirty(handle, inode, path + k);
1101                 if (err)
1102                         break;
1103         }
1104
1105         return err;
1106 }
1107
1108 static int inline
1109 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1110                                 struct ext4_extent *ex2)
1111 {
1112         if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) !=
1113                         le32_to_cpu(ex2->ee_block))
1114                 return 0;
1115
1116         /*
1117          * To allow future support for preallocated extents to be added
1118          * as an RO_COMPAT feature, refuse to merge to extents if
1119          * this can result in the top bit of ee_len being set.
1120          */
1121         if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
1122                 return 0;
1123 #ifdef AGRESSIVE_TEST
1124         if (le16_to_cpu(ex1->ee_len) >= 4)
1125                 return 0;
1126 #endif
1127
1128         if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
1129                 return 1;
1130         return 0;
1131 }
1132
1133 /*
1134  * ext4_ext_insert_extent:
1135  * tries to merge requsted extent into the existing extent or
1136  * inserts requested extent as new one into the tree,
1137  * creating new leaf in the no-space case.
1138  */
1139 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1140                                 struct ext4_ext_path *path,
1141                                 struct ext4_extent *newext)
1142 {
1143         struct ext4_extent_header * eh;
1144         struct ext4_extent *ex, *fex;
1145         struct ext4_extent *nearex; /* nearest extent */
1146         struct ext4_ext_path *npath = NULL;
1147         int depth, len, err, next;
1148
1149         BUG_ON(newext->ee_len == 0);
1150         depth = ext_depth(inode);
1151         ex = path[depth].p_ext;
1152         BUG_ON(path[depth].p_hdr == NULL);
1153
1154         /* try to insert block into found extent and return */
1155         if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
1156                 ext_debug("append %d block to %d:%d (from %llu)\n",
1157                                 le16_to_cpu(newext->ee_len),
1158                                 le32_to_cpu(ex->ee_block),
1159                                 le16_to_cpu(ex->ee_len), ext_pblock(ex));
1160                 err = ext4_ext_get_access(handle, inode, path + depth);
1161                 if (err)
1162                         return err;
1163                 ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
1164                                          + le16_to_cpu(newext->ee_len));
1165                 eh = path[depth].p_hdr;
1166                 nearex = ex;
1167                 goto merge;
1168         }
1169
1170 repeat:
1171         depth = ext_depth(inode);
1172         eh = path[depth].p_hdr;
1173         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1174                 goto has_space;
1175
1176         /* probably next leaf has space for us? */
1177         fex = EXT_LAST_EXTENT(eh);
1178         next = ext4_ext_next_leaf_block(inode, path);
1179         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1180             && next != EXT_MAX_BLOCK) {
1181                 ext_debug("next leaf block - %d\n", next);
1182                 BUG_ON(npath != NULL);
1183                 npath = ext4_ext_find_extent(inode, next, NULL);
1184                 if (IS_ERR(npath))
1185                         return PTR_ERR(npath);
1186                 BUG_ON(npath->p_depth != path->p_depth);
1187                 eh = npath[depth].p_hdr;
1188                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1189                         ext_debug("next leaf isnt full(%d)\n",
1190                                   le16_to_cpu(eh->eh_entries));
1191                         path = npath;
1192                         goto repeat;
1193                 }
1194                 ext_debug("next leaf has no free space(%d,%d)\n",
1195                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1196         }
1197
1198         /*
1199          * There is no free space in the found leaf.
1200          * We're gonna add a new leaf in the tree.
1201          */
1202         err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1203         if (err)
1204                 goto cleanup;
1205         depth = ext_depth(inode);
1206         eh = path[depth].p_hdr;
1207
1208 has_space:
1209         nearex = path[depth].p_ext;
1210
1211         err = ext4_ext_get_access(handle, inode, path + depth);
1212         if (err)
1213                 goto cleanup;
1214
1215         if (!nearex) {
1216                 /* there is no extent in this leaf, create first one */
1217                 ext_debug("first extent in the leaf: %d:%llu:%d\n",
1218                                 le32_to_cpu(newext->ee_block),
1219                                 ext_pblock(newext),
1220                                 le16_to_cpu(newext->ee_len));
1221                 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1222         } else if (le32_to_cpu(newext->ee_block)
1223                            > le32_to_cpu(nearex->ee_block)) {
1224 /*              BUG_ON(newext->ee_block == nearex->ee_block); */
1225                 if (nearex != EXT_LAST_EXTENT(eh)) {
1226                         len = EXT_MAX_EXTENT(eh) - nearex;
1227                         len = (len - 1) * sizeof(struct ext4_extent);
1228                         len = len < 0 ? 0 : len;
1229                         ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
1230                                         "move %d from 0x%p to 0x%p\n",
1231                                         le32_to_cpu(newext->ee_block),
1232                                         ext_pblock(newext),
1233                                         le16_to_cpu(newext->ee_len),
1234                                         nearex, len, nearex + 1, nearex + 2);
1235                         memmove(nearex + 2, nearex + 1, len);
1236                 }
1237                 path[depth].p_ext = nearex + 1;
1238         } else {
1239                 BUG_ON(newext->ee_block == nearex->ee_block);
1240                 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1241                 len = len < 0 ? 0 : len;
1242                 ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
1243                                 "move %d from 0x%p to 0x%p\n",
1244                                 le32_to_cpu(newext->ee_block),
1245                                 ext_pblock(newext),
1246                                 le16_to_cpu(newext->ee_len),
1247                                 nearex, len, nearex + 1, nearex + 2);
1248                 memmove(nearex + 1, nearex, len);
1249                 path[depth].p_ext = nearex;
1250         }
1251
1252         eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
1253         nearex = path[depth].p_ext;
1254         nearex->ee_block = newext->ee_block;
1255         nearex->ee_start = newext->ee_start;
1256         nearex->ee_start_hi = newext->ee_start_hi;
1257         nearex->ee_len = newext->ee_len;
1258
1259 merge:
1260         /* try to merge extents to the right */
1261         while (nearex < EXT_LAST_EXTENT(eh)) {
1262                 if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
1263                         break;
1264                 /* merge with next extent! */
1265                 nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
1266                                              + le16_to_cpu(nearex[1].ee_len));
1267                 if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
1268                         len = (EXT_LAST_EXTENT(eh) - nearex - 1)
1269                                         * sizeof(struct ext4_extent);
1270                         memmove(nearex + 1, nearex + 2, len);
1271                 }
1272                 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1273                 BUG_ON(eh->eh_entries == 0);
1274         }
1275
1276         /* try to merge extents to the left */
1277
1278         /* time to correct all indexes above */
1279         err = ext4_ext_correct_indexes(handle, inode, path);
1280         if (err)
1281                 goto cleanup;
1282
1283         err = ext4_ext_dirty(handle, inode, path + depth);
1284
1285 cleanup:
1286         if (npath) {
1287                 ext4_ext_drop_refs(npath);
1288                 kfree(npath);
1289         }
1290         ext4_ext_tree_changed(inode);
1291         ext4_ext_invalidate_cache(inode);
1292         return err;
1293 }
1294
1295 int ext4_ext_walk_space(struct inode *inode, unsigned long block,
1296                         unsigned long num, ext_prepare_callback func,
1297                         void *cbdata)
1298 {
1299         struct ext4_ext_path *path = NULL;
1300         struct ext4_ext_cache cbex;
1301         struct ext4_extent *ex;
1302         unsigned long next, start = 0, end = 0;
1303         unsigned long last = block + num;
1304         int depth, exists, err = 0;
1305
1306         BUG_ON(func == NULL);
1307         BUG_ON(inode == NULL);
1308
1309         while (block < last && block != EXT_MAX_BLOCK) {
1310                 num = last - block;
1311                 /* find extent for this block */
1312                 path = ext4_ext_find_extent(inode, block, path);
1313                 if (IS_ERR(path)) {
1314                         err = PTR_ERR(path);
1315                         path = NULL;
1316                         break;
1317                 }
1318
1319                 depth = ext_depth(inode);
1320                 BUG_ON(path[depth].p_hdr == NULL);
1321                 ex = path[depth].p_ext;
1322                 next = ext4_ext_next_allocated_block(path);
1323
1324                 exists = 0;
1325                 if (!ex) {
1326                         /* there is no extent yet, so try to allocate
1327                          * all requested space */
1328                         start = block;
1329                         end = block + num;
1330                 } else if (le32_to_cpu(ex->ee_block) > block) {
1331                         /* need to allocate space before found extent */
1332                         start = block;
1333                         end = le32_to_cpu(ex->ee_block);
1334                         if (block + num < end)
1335                                 end = block + num;
1336                 } else if (block >=
1337                              le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) {
1338                         /* need to allocate space after found extent */
1339                         start = block;
1340                         end = block + num;
1341                         if (end >= next)
1342                                 end = next;
1343                 } else if (block >= le32_to_cpu(ex->ee_block)) {
1344                         /*
1345                          * some part of requested space is covered
1346                          * by found extent
1347                          */
1348                         start = block;
1349                         end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len);
1350                         if (block + num < end)
1351                                 end = block + num;
1352                         exists = 1;
1353                 } else {
1354                         BUG();
1355                 }
1356                 BUG_ON(end <= start);
1357
1358                 if (!exists) {
1359                         cbex.ec_block = start;
1360                         cbex.ec_len = end - start;
1361                         cbex.ec_start = 0;
1362                         cbex.ec_type = EXT4_EXT_CACHE_GAP;
1363                 } else {
1364                         cbex.ec_block = le32_to_cpu(ex->ee_block);
1365                         cbex.ec_len = le16_to_cpu(ex->ee_len);
1366                         cbex.ec_start = ext_pblock(ex);
1367                         cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
1368                 }
1369
1370                 BUG_ON(cbex.ec_len == 0);
1371                 err = func(inode, path, &cbex, cbdata);
1372                 ext4_ext_drop_refs(path);
1373
1374                 if (err < 0)
1375                         break;
1376                 if (err == EXT_REPEAT)
1377                         continue;
1378                 else if (err == EXT_BREAK) {
1379                         err = 0;
1380                         break;
1381                 }
1382
1383                 if (ext_depth(inode) != depth) {
1384                         /* depth was changed. we have to realloc path */
1385                         kfree(path);
1386                         path = NULL;
1387                 }
1388
1389                 block = cbex.ec_block + cbex.ec_len;
1390         }
1391
1392         if (path) {
1393                 ext4_ext_drop_refs(path);
1394                 kfree(path);
1395         }
1396
1397         return err;
1398 }
1399
1400 static inline void
1401 ext4_ext_put_in_cache(struct inode *inode, __u32 block,
1402                         __u32 len, __u32 start, int type)
1403 {
1404         struct ext4_ext_cache *cex;
1405         BUG_ON(len == 0);
1406         cex = &EXT4_I(inode)->i_cached_extent;
1407         cex->ec_type = type;
1408         cex->ec_block = block;
1409         cex->ec_len = len;
1410         cex->ec_start = start;
1411 }
1412
1413 /*
1414  * ext4_ext_put_gap_in_cache:
1415  * calculate boundaries of the gap that the requested block fits into
1416  * and cache this gap
1417  */
1418 static inline void
1419 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1420                                 unsigned long block)
1421 {
1422         int depth = ext_depth(inode);
1423         unsigned long lblock, len;
1424         struct ext4_extent *ex;
1425
1426         ex = path[depth].p_ext;
1427         if (ex == NULL) {
1428                 /* there is no extent yet, so gap is [0;-] */
1429                 lblock = 0;
1430                 len = EXT_MAX_BLOCK;
1431                 ext_debug("cache gap(whole file):");
1432         } else if (block < le32_to_cpu(ex->ee_block)) {
1433                 lblock = block;
1434                 len = le32_to_cpu(ex->ee_block) - block;
1435                 ext_debug("cache gap(before): %lu [%lu:%lu]",
1436                                 (unsigned long) block,
1437                                 (unsigned long) le32_to_cpu(ex->ee_block),
1438                                 (unsigned long) le16_to_cpu(ex->ee_len));
1439         } else if (block >= le32_to_cpu(ex->ee_block)
1440                             + le16_to_cpu(ex->ee_len)) {
1441                 lblock = le32_to_cpu(ex->ee_block)
1442                          + le16_to_cpu(ex->ee_len);
1443                 len = ext4_ext_next_allocated_block(path);
1444                 ext_debug("cache gap(after): [%lu:%lu] %lu",
1445                                 (unsigned long) le32_to_cpu(ex->ee_block),
1446                                 (unsigned long) le16_to_cpu(ex->ee_len),
1447                                 (unsigned long) block);
1448                 BUG_ON(len == lblock);
1449                 len = len - lblock;
1450         } else {
1451                 lblock = len = 0;
1452                 BUG();
1453         }
1454
1455         ext_debug(" -> %lu:%lu\n", (unsigned long) lblock, len);
1456         ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1457 }
1458
1459 static inline int
1460 ext4_ext_in_cache(struct inode *inode, unsigned long block,
1461                         struct ext4_extent *ex)
1462 {
1463         struct ext4_ext_cache *cex;
1464
1465         cex = &EXT4_I(inode)->i_cached_extent;
1466
1467         /* has cache valid data? */
1468         if (cex->ec_type == EXT4_EXT_CACHE_NO)
1469                 return EXT4_EXT_CACHE_NO;
1470
1471         BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1472                         cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1473         if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
1474                 ex->ee_block = cpu_to_le32(cex->ec_block);
1475                 ext4_ext_store_pblock(ex, cex->ec_start);
1476                 ex->ee_len = cpu_to_le16(cex->ec_len);
1477                 ext_debug("%lu cached by %lu:%lu:%llu\n",
1478                                 (unsigned long) block,
1479                                 (unsigned long) cex->ec_block,
1480                                 (unsigned long) cex->ec_len,
1481                                 cex->ec_start);
1482                 return cex->ec_type;
1483         }
1484
1485         /* not in cache */
1486         return EXT4_EXT_CACHE_NO;
1487 }
1488
1489 /*
1490  * ext4_ext_rm_idx:
1491  * removes index from the index block.
1492  * It's used in truncate case only, thus all requests are for
1493  * last index in the block only.
1494  */
1495 int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1496                         struct ext4_ext_path *path)
1497 {
1498         struct buffer_head *bh;
1499         int err;
1500         ext4_fsblk_t leaf;
1501
1502         /* free index block */
1503         path--;
1504         leaf = idx_pblock(path->p_idx);
1505         BUG_ON(path->p_hdr->eh_entries == 0);
1506         err = ext4_ext_get_access(handle, inode, path);
1507         if (err)
1508                 return err;
1509         path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
1510         err = ext4_ext_dirty(handle, inode, path);
1511         if (err)
1512                 return err;
1513         ext_debug("index is empty, remove it, free block %llu\n", leaf);
1514         bh = sb_find_get_block(inode->i_sb, leaf);
1515         ext4_forget(handle, 1, inode, bh, leaf);
1516         ext4_free_blocks(handle, inode, leaf, 1);
1517         return err;
1518 }
1519
1520 /*
1521  * ext4_ext_calc_credits_for_insert:
1522  * This routine returns max. credits that the extent tree can consume.
1523  * It should be OK for low-performance paths like ->writepage()
1524  * To allow many writing processes to fit into a single transaction,
1525  * the caller should calculate credits under truncate_mutex and
1526  * pass the actual path.
1527  */
1528 int inline ext4_ext_calc_credits_for_insert(struct inode *inode,
1529                                                 struct ext4_ext_path *path)
1530 {
1531         int depth, needed;
1532
1533         if (path) {
1534                 /* probably there is space in leaf? */
1535                 depth = ext_depth(inode);
1536                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1537                                 < le16_to_cpu(path[depth].p_hdr->eh_max))
1538                         return 1;
1539         }
1540
1541         /*
1542          * given 32-bit logical block (4294967296 blocks), max. tree
1543          * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
1544          * Let's also add one more level for imbalance.
1545          */
1546         depth = 5;
1547
1548         /* allocation of new data block(s) */
1549         needed = 2;
1550
1551         /*
1552          * tree can be full, so it would need to grow in depth:
1553          * we need one credit to modify old root, credits for
1554          * new root will be added in split accounting
1555          */
1556         needed += 1;
1557
1558         /*
1559          * Index split can happen, we would need:
1560          *    allocate intermediate indexes (bitmap + group)
1561          *  + change two blocks at each level, but root (already included)
1562          */
1563         needed += (depth * 2) + (depth * 2);
1564
1565         /* any allocation modifies superblock */
1566         needed += 1;
1567
1568         return needed;
1569 }
1570
1571 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
1572                                 struct ext4_extent *ex,
1573                                 unsigned long from, unsigned long to)
1574 {
1575         struct buffer_head *bh;
1576         int i;
1577
1578 #ifdef EXTENTS_STATS
1579         {
1580                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1581                 unsigned short ee_len =  le16_to_cpu(ex->ee_len);
1582                 spin_lock(&sbi->s_ext_stats_lock);
1583                 sbi->s_ext_blocks += ee_len;
1584                 sbi->s_ext_extents++;
1585                 if (ee_len < sbi->s_ext_min)
1586                         sbi->s_ext_min = ee_len;
1587                 if (ee_len > sbi->s_ext_max)
1588                         sbi->s_ext_max = ee_len;
1589                 if (ext_depth(inode) > sbi->s_depth_max)
1590                         sbi->s_depth_max = ext_depth(inode);
1591                 spin_unlock(&sbi->s_ext_stats_lock);
1592         }
1593 #endif
1594         if (from >= le32_to_cpu(ex->ee_block)
1595             && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
1596                 /* tail removal */
1597                 unsigned long num;
1598                 ext4_fsblk_t start;
1599                 num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
1600                 start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
1601                 ext_debug("free last %lu blocks starting %llu\n", num, start);
1602                 for (i = 0; i < num; i++) {
1603                         bh = sb_find_get_block(inode->i_sb, start + i);
1604                         ext4_forget(handle, 0, inode, bh, start + i);
1605                 }
1606                 ext4_free_blocks(handle, inode, start, num);
1607         } else if (from == le32_to_cpu(ex->ee_block)
1608                    && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
1609                 printk("strange request: removal %lu-%lu from %u:%u\n",
1610                        from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
1611         } else {
1612                 printk("strange request: removal(2) %lu-%lu from %u:%u\n",
1613                        from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
1614         }
1615         return 0;
1616 }
1617
1618 static int
1619 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
1620                 struct ext4_ext_path *path, unsigned long start)
1621 {
1622         int err = 0, correct_index = 0;
1623         int depth = ext_depth(inode), credits;
1624         struct ext4_extent_header *eh;
1625         unsigned a, b, block, num;
1626         unsigned long ex_ee_block;
1627         unsigned short ex_ee_len;
1628         struct ext4_extent *ex;
1629
1630         ext_debug("truncate since %lu in leaf\n", start);
1631         if (!path[depth].p_hdr)
1632                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
1633         eh = path[depth].p_hdr;
1634         BUG_ON(eh == NULL);
1635         BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
1636         BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
1637
1638         /* find where to start removing */
1639         ex = EXT_LAST_EXTENT(eh);
1640
1641         ex_ee_block = le32_to_cpu(ex->ee_block);
1642         ex_ee_len = le16_to_cpu(ex->ee_len);
1643
1644         while (ex >= EXT_FIRST_EXTENT(eh) &&
1645                         ex_ee_block + ex_ee_len > start) {
1646                 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
1647                 path[depth].p_ext = ex;
1648
1649                 a = ex_ee_block > start ? ex_ee_block : start;
1650                 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
1651                         ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
1652
1653                 ext_debug("  border %u:%u\n", a, b);
1654
1655                 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
1656                         block = 0;
1657                         num = 0;
1658                         BUG();
1659                 } else if (a != ex_ee_block) {
1660                         /* remove tail of the extent */
1661                         block = ex_ee_block;
1662                         num = a - block;
1663                 } else if (b != ex_ee_block + ex_ee_len - 1) {
1664                         /* remove head of the extent */
1665                         block = a;
1666                         num = b - a;
1667                         /* there is no "make a hole" API yet */
1668                         BUG();
1669                 } else {
1670                         /* remove whole extent: excellent! */
1671                         block = ex_ee_block;
1672                         num = 0;
1673                         BUG_ON(a != ex_ee_block);
1674                         BUG_ON(b != ex_ee_block + ex_ee_len - 1);
1675                 }
1676
1677                 /* at present, extent can't cross block group: */
1678                 /* leaf + bitmap + group desc + sb + inode */
1679                 credits = 5;
1680                 if (ex == EXT_FIRST_EXTENT(eh)) {
1681                         correct_index = 1;
1682                         credits += (ext_depth(inode)) + 1;
1683                 }
1684 #ifdef CONFIG_QUOTA
1685                 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
1686 #endif
1687
1688                 handle = ext4_ext_journal_restart(handle, credits);
1689                 if (IS_ERR(handle)) {
1690                         err = PTR_ERR(handle);
1691                         goto out;
1692                 }
1693
1694                 err = ext4_ext_get_access(handle, inode, path + depth);
1695                 if (err)
1696                         goto out;
1697
1698                 err = ext4_remove_blocks(handle, inode, ex, a, b);
1699                 if (err)
1700                         goto out;
1701
1702                 if (num == 0) {
1703                         /* this extent is removed; mark slot entirely unused */
1704                         ext4_ext_store_pblock(ex, 0);
1705                         eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1706                 }
1707
1708                 ex->ee_block = cpu_to_le32(block);
1709                 ex->ee_len = cpu_to_le16(num);
1710
1711                 err = ext4_ext_dirty(handle, inode, path + depth);
1712                 if (err)
1713                         goto out;
1714
1715                 ext_debug("new extent: %u:%u:%llu\n", block, num,
1716                                 ext_pblock(ex));
1717                 ex--;
1718                 ex_ee_block = le32_to_cpu(ex->ee_block);
1719                 ex_ee_len = le16_to_cpu(ex->ee_len);
1720         }
1721
1722         if (correct_index && eh->eh_entries)
1723                 err = ext4_ext_correct_indexes(handle, inode, path);
1724
1725         /* if this leaf is free, then we should
1726          * remove it from index block above */
1727         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
1728                 err = ext4_ext_rm_idx(handle, inode, path + depth);
1729
1730 out:
1731         return err;
1732 }
1733
1734 /*
1735  * ext4_ext_more_to_rm:
1736  * returns 1 if current index has to be freed (even partial)
1737  */
1738 static int inline
1739 ext4_ext_more_to_rm(struct ext4_ext_path *path)
1740 {
1741         BUG_ON(path->p_idx == NULL);
1742
1743         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
1744                 return 0;
1745
1746         /*
1747          * if truncate on deeper level happened, it wasn't partial,
1748          * so we have to consider current index for truncation
1749          */
1750         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
1751                 return 0;
1752         return 1;
1753 }
1754
1755 int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1756 {
1757         struct super_block *sb = inode->i_sb;
1758         int depth = ext_depth(inode);
1759         struct ext4_ext_path *path;
1760         handle_t *handle;
1761         int i = 0, err = 0;
1762
1763         ext_debug("truncate since %lu\n", start);
1764
1765         /* probably first extent we're gonna free will be last in block */
1766         handle = ext4_journal_start(inode, depth + 1);
1767         if (IS_ERR(handle))
1768                 return PTR_ERR(handle);
1769
1770         ext4_ext_invalidate_cache(inode);
1771
1772         /*
1773          * We start scanning from right side, freeing all the blocks
1774          * after i_size and walking into the tree depth-wise.
1775          */
1776         path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
1777         if (path == NULL) {
1778                 ext4_journal_stop(handle);
1779                 return -ENOMEM;
1780         }
1781         memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
1782         path[0].p_hdr = ext_inode_hdr(inode);
1783         if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) {
1784                 err = -EIO;
1785                 goto out;
1786         }
1787         path[0].p_depth = depth;
1788
1789         while (i >= 0 && err == 0) {
1790                 if (i == depth) {
1791                         /* this is leaf block */
1792                         err = ext4_ext_rm_leaf(handle, inode, path, start);
1793                         /* root level has p_bh == NULL, brelse() eats this */
1794                         brelse(path[i].p_bh);
1795                         path[i].p_bh = NULL;
1796                         i--;
1797                         continue;
1798                 }
1799
1800                 /* this is index block */
1801                 if (!path[i].p_hdr) {
1802                         ext_debug("initialize header\n");
1803                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
1804                         if (ext4_ext_check_header(__FUNCTION__, inode,
1805                                                         path[i].p_hdr)) {
1806                                 err = -EIO;
1807                                 goto out;
1808                         }
1809                 }
1810
1811                 BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries)
1812                            > le16_to_cpu(path[i].p_hdr->eh_max));
1813                 BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
1814
1815                 if (!path[i].p_idx) {
1816                         /* this level hasn't been touched yet */
1817                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
1818                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
1819                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
1820                                   path[i].p_hdr,
1821                                   le16_to_cpu(path[i].p_hdr->eh_entries));
1822                 } else {
1823                         /* we were already here, see at next index */
1824                         path[i].p_idx--;
1825                 }
1826
1827                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
1828                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
1829                                 path[i].p_idx);
1830                 if (ext4_ext_more_to_rm(path + i)) {
1831                         /* go to the next level */
1832                         ext_debug("move to level %d (block %llu)\n",
1833                                   i + 1, idx_pblock(path[i].p_idx));
1834                         memset(path + i + 1, 0, sizeof(*path));
1835                         path[i+1].p_bh =
1836                                 sb_bread(sb, idx_pblock(path[i].p_idx));
1837                         if (!path[i+1].p_bh) {
1838                                 /* should we reset i_size? */
1839                                 err = -EIO;
1840                                 break;
1841                         }
1842
1843                         /* save actual number of indexes since this
1844                          * number is changed at the next iteration */
1845                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
1846                         i++;
1847                 } else {
1848                         /* we finished processing this index, go up */
1849                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
1850                                 /* index is empty, remove it;
1851                                  * handle must be already prepared by the
1852                                  * truncatei_leaf() */
1853                                 err = ext4_ext_rm_idx(handle, inode, path + i);
1854                         }
1855                         /* root level has p_bh == NULL, brelse() eats this */
1856                         brelse(path[i].p_bh);
1857                         path[i].p_bh = NULL;
1858                         i--;
1859                         ext_debug("return to level %d\n", i);
1860                 }
1861         }
1862
1863         /* TODO: flexible tree reduction should be here */
1864         if (path->p_hdr->eh_entries == 0) {
1865                 /*
1866                  * truncate to zero freed all the tree,
1867                  * so we need to correct eh_depth
1868                  */
1869                 err = ext4_ext_get_access(handle, inode, path);
1870                 if (err == 0) {
1871                         ext_inode_hdr(inode)->eh_depth = 0;
1872                         ext_inode_hdr(inode)->eh_max =
1873                                 cpu_to_le16(ext4_ext_space_root(inode));
1874                         err = ext4_ext_dirty(handle, inode, path);
1875                 }
1876         }
1877 out:
1878         ext4_ext_tree_changed(inode);
1879         ext4_ext_drop_refs(path);
1880         kfree(path);
1881         ext4_journal_stop(handle);
1882
1883         return err;
1884 }
1885
1886 /*
1887  * called at mount time
1888  */
1889 void ext4_ext_init(struct super_block *sb)
1890 {
1891         /*
1892          * possible initialization would be here
1893          */
1894
1895         if (test_opt(sb, EXTENTS)) {
1896                 printk("EXT4-fs: file extents enabled");
1897 #ifdef AGRESSIVE_TEST
1898                 printk(", agressive tests");
1899 #endif
1900 #ifdef CHECK_BINSEARCH
1901                 printk(", check binsearch");
1902 #endif
1903 #ifdef EXTENTS_STATS
1904                 printk(", stats");
1905 #endif
1906                 printk("\n");
1907 #ifdef EXTENTS_STATS
1908                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
1909                 EXT4_SB(sb)->s_ext_min = 1 << 30;
1910                 EXT4_SB(sb)->s_ext_max = 0;
1911 #endif
1912         }
1913 }
1914
1915 /*
1916  * called at umount time
1917  */
1918 void ext4_ext_release(struct super_block *sb)
1919 {
1920         if (!test_opt(sb, EXTENTS))
1921                 return;
1922
1923 #ifdef EXTENTS_STATS
1924         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
1925                 struct ext4_sb_info *sbi = EXT4_SB(sb);
1926                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
1927                         sbi->s_ext_blocks, sbi->s_ext_extents,
1928                         sbi->s_ext_blocks / sbi->s_ext_extents);
1929                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
1930                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
1931         }
1932 #endif
1933 }
1934
1935 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
1936                         ext4_fsblk_t iblock,
1937                         unsigned long max_blocks, struct buffer_head *bh_result,
1938                         int create, int extend_disksize)
1939 {
1940         struct ext4_ext_path *path = NULL;
1941         struct ext4_extent newex, *ex;
1942         ext4_fsblk_t goal, newblock;
1943         int err = 0, depth;
1944         unsigned long allocated = 0;
1945
1946         __clear_bit(BH_New, &bh_result->b_state);
1947         ext_debug("blocks %d/%lu requested for inode %u\n", (int) iblock,
1948                         max_blocks, (unsigned) inode->i_ino);
1949         mutex_lock(&EXT4_I(inode)->truncate_mutex);
1950
1951         /* check in cache */
1952         goal = ext4_ext_in_cache(inode, iblock, &newex);
1953         if (goal) {
1954                 if (goal == EXT4_EXT_CACHE_GAP) {
1955                         if (!create) {
1956                                 /* block isn't allocated yet and
1957                                  * user doesn't want to allocate it */
1958                                 goto out2;
1959                         }
1960                         /* we should allocate requested block */
1961                 } else if (goal == EXT4_EXT_CACHE_EXTENT) {
1962                         /* block is already allocated */
1963                         newblock = iblock
1964                                    - le32_to_cpu(newex.ee_block)
1965                                    + ext_pblock(&newex);
1966                         /* number of remaining blocks in the extent */
1967                         allocated = le16_to_cpu(newex.ee_len) -
1968                                         (iblock - le32_to_cpu(newex.ee_block));
1969                         goto out;
1970                 } else {
1971                         BUG();
1972                 }
1973         }
1974
1975         /* find extent for this block */
1976         path = ext4_ext_find_extent(inode, iblock, NULL);
1977         if (IS_ERR(path)) {
1978                 err = PTR_ERR(path);
1979                 path = NULL;
1980                 goto out2;
1981         }
1982
1983         depth = ext_depth(inode);
1984
1985         /*
1986          * consistent leaf must not be empty;
1987          * this situation is possible, though, _during_ tree modification;
1988          * this is why assert can't be put in ext4_ext_find_extent()
1989          */
1990         BUG_ON(path[depth].p_ext == NULL && depth != 0);
1991
1992         ex = path[depth].p_ext;
1993         if (ex) {
1994                 unsigned long ee_block = le32_to_cpu(ex->ee_block);
1995                 ext4_fsblk_t ee_start = ext_pblock(ex);
1996                 unsigned short ee_len  = le16_to_cpu(ex->ee_len);
1997
1998                 /*
1999                  * Allow future support for preallocated extents to be added
2000                  * as an RO_COMPAT feature:
2001                  * Uninitialized extents are treated as holes, except that
2002                  * we avoid (fail) allocating new blocks during a write.
2003                  */
2004                 if (ee_len > EXT_MAX_LEN)
2005                         goto out2;
2006                 /* if found extent covers block, simply return it */
2007                 if (iblock >= ee_block && iblock < ee_block + ee_len) {
2008                         newblock = iblock - ee_block + ee_start;
2009                         /* number of remaining blocks in the extent */
2010                         allocated = ee_len - (iblock - ee_block);
2011                         ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock,
2012                                         ee_block, ee_len, newblock);
2013                         ext4_ext_put_in_cache(inode, ee_block, ee_len,
2014                                                 ee_start, EXT4_EXT_CACHE_EXTENT);
2015                         goto out;
2016                 }
2017         }
2018
2019         /*
2020          * requested block isn't allocated yet;
2021          * we couldn't try to create block if create flag is zero
2022          */
2023         if (!create) {
2024                 /* put just found gap into cache to speed up
2025                  * subsequent requests */
2026                 ext4_ext_put_gap_in_cache(inode, path, iblock);
2027                 goto out2;
2028         }
2029         /*
2030          * Okay, we need to do block allocation.  Lazily initialize the block
2031          * allocation info here if necessary.
2032          */
2033         if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
2034                 ext4_init_block_alloc_info(inode);
2035
2036         /* allocate new block */
2037         goal = ext4_ext_find_goal(inode, path, iblock);
2038         allocated = max_blocks;
2039         newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
2040         if (!newblock)
2041                 goto out2;
2042         ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
2043                         goal, newblock, allocated);
2044
2045         /* try to insert new extent into found leaf and return */
2046         newex.ee_block = cpu_to_le32(iblock);
2047         ext4_ext_store_pblock(&newex, newblock);
2048         newex.ee_len = cpu_to_le16(allocated);
2049         err = ext4_ext_insert_extent(handle, inode, path, &newex);
2050         if (err)
2051                 goto out2;
2052
2053         if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
2054                 EXT4_I(inode)->i_disksize = inode->i_size;
2055
2056         /* previous routine could use block we allocated */
2057         newblock = ext_pblock(&newex);
2058         __set_bit(BH_New, &bh_result->b_state);
2059
2060         ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
2061                                 EXT4_EXT_CACHE_EXTENT);
2062 out:
2063         if (allocated > max_blocks)
2064                 allocated = max_blocks;
2065         ext4_ext_show_leaf(inode, path);
2066         __set_bit(BH_Mapped, &bh_result->b_state);
2067         bh_result->b_bdev = inode->i_sb->s_bdev;
2068         bh_result->b_blocknr = newblock;
2069 out2:
2070         if (path) {
2071                 ext4_ext_drop_refs(path);
2072                 kfree(path);
2073         }
2074         mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2075
2076         return err ? err : allocated;
2077 }
2078
2079 void ext4_ext_truncate(struct inode * inode, struct page *page)
2080 {
2081         struct address_space *mapping = inode->i_mapping;
2082         struct super_block *sb = inode->i_sb;
2083         unsigned long last_block;
2084         handle_t *handle;
2085         int err = 0;
2086
2087         /*
2088          * probably first extent we're gonna free will be last in block
2089          */
2090         err = ext4_writepage_trans_blocks(inode) + 3;
2091         handle = ext4_journal_start(inode, err);
2092         if (IS_ERR(handle)) {
2093                 if (page) {
2094                         clear_highpage(page);
2095                         flush_dcache_page(page);
2096                         unlock_page(page);
2097                         page_cache_release(page);
2098                 }
2099                 return;
2100         }
2101
2102         if (page)
2103                 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2104
2105         mutex_lock(&EXT4_I(inode)->truncate_mutex);
2106         ext4_ext_invalidate_cache(inode);
2107
2108         /*
2109          * TODO: optimization is possible here.
2110          * Probably we need not scan at all,
2111          * because page truncation is enough.
2112          */
2113         if (ext4_orphan_add(handle, inode))
2114                 goto out_stop;
2115
2116         /* we have to know where to truncate from in crash case */
2117         EXT4_I(inode)->i_disksize = inode->i_size;
2118         ext4_mark_inode_dirty(handle, inode);
2119
2120         last_block = (inode->i_size + sb->s_blocksize - 1)
2121                         >> EXT4_BLOCK_SIZE_BITS(sb);
2122         err = ext4_ext_remove_space(inode, last_block);
2123
2124         /* In a multi-transaction truncate, we only make the final
2125          * transaction synchronous. */
2126         if (IS_SYNC(inode))
2127                 handle->h_sync = 1;
2128
2129 out_stop:
2130         /*
2131          * If this was a simple ftruncate() and the file will remain alive,
2132          * then we need to clear up the orphan record which we created above.
2133          * However, if this was a real unlink then we were called by
2134          * ext4_delete_inode(), and we allow that function to clean up the
2135          * orphan info for us.
2136          */
2137         if (inode->i_nlink)
2138                 ext4_orphan_del(handle, inode);
2139
2140         mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2141         ext4_journal_stop(handle);
2142 }
2143
2144 /*
2145  * ext4_ext_writepage_trans_blocks:
2146  * calculate max number of blocks we could modify
2147  * in order to allocate new block for an inode
2148  */
2149 int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
2150 {
2151         int needed;
2152
2153         needed = ext4_ext_calc_credits_for_insert(inode, NULL);
2154
2155         /* caller wants to allocate num blocks, but note it includes sb */
2156         needed = needed * num - (num - 1);
2157
2158 #ifdef CONFIG_QUOTA
2159         needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
2160 #endif
2161
2162         return needed;
2163 }
2164
2165 EXPORT_SYMBOL(ext4_mark_inode_dirty);
2166 EXPORT_SYMBOL(ext4_ext_invalidate_cache);
2167 EXPORT_SYMBOL(ext4_ext_insert_extent);
2168 EXPORT_SYMBOL(ext4_ext_walk_space);
2169 EXPORT_SYMBOL(ext4_ext_find_goal);
2170 EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert);
2171