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hfsplus: rework processing errors in hfsplus_free_extents()
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1 /*
2  *  linux/fs/hfsplus/extents.c
3  *
4  * Copyright (C) 2001
5  * Brad Boyer (flar@allandria.com)
6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
7  *
8  * Handling of Extents both in catalog and extents overflow trees
9  */
10
11 #include <linux/errno.h>
12 #include <linux/fs.h>
13 #include <linux/pagemap.h>
14
15 #include "hfsplus_fs.h"
16 #include "hfsplus_raw.h"
17
18 /* Compare two extents keys, returns 0 on same, pos/neg for difference */
19 int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
20                         const hfsplus_btree_key *k2)
21 {
22         __be32 k1id, k2id;
23         __be32 k1s, k2s;
24
25         k1id = k1->ext.cnid;
26         k2id = k2->ext.cnid;
27         if (k1id != k2id)
28                 return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
29
30         if (k1->ext.fork_type != k2->ext.fork_type)
31                 return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
32
33         k1s = k1->ext.start_block;
34         k2s = k2->ext.start_block;
35         if (k1s == k2s)
36                 return 0;
37         return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
38 }
39
40 static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
41                                   u32 block, u8 type)
42 {
43         key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
44         key->ext.cnid = cpu_to_be32(cnid);
45         key->ext.start_block = cpu_to_be32(block);
46         key->ext.fork_type = type;
47         key->ext.pad = 0;
48 }
49
50 static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
51 {
52         int i;
53         u32 count;
54
55         for (i = 0; i < 8; ext++, i++) {
56                 count = be32_to_cpu(ext->block_count);
57                 if (off < count)
58                         return be32_to_cpu(ext->start_block) + off;
59                 off -= count;
60         }
61         /* panic? */
62         return 0;
63 }
64
65 static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
66 {
67         int i;
68         u32 count = 0;
69
70         for (i = 0; i < 8; ext++, i++)
71                 count += be32_to_cpu(ext->block_count);
72         return count;
73 }
74
75 static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
76 {
77         int i;
78
79         ext += 7;
80         for (i = 0; i < 7; ext--, i++)
81                 if (ext->block_count)
82                         break;
83         return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
84 }
85
86 static void __hfsplus_ext_write_extent(struct inode *inode,
87                 struct hfs_find_data *fd)
88 {
89         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
90         int res;
91
92         WARN_ON(!mutex_is_locked(&hip->extents_lock));
93
94         hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
95                               HFSPLUS_IS_RSRC(inode) ?
96                                 HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
97
98         res = hfs_brec_find(fd);
99         if (hip->extent_state & HFSPLUS_EXT_NEW) {
100                 if (res != -ENOENT)
101                         return;
102                 hfs_brec_insert(fd, hip->cached_extents,
103                                 sizeof(hfsplus_extent_rec));
104                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
105         } else {
106                 if (res)
107                         return;
108                 hfs_bnode_write(fd->bnode, hip->cached_extents,
109                                 fd->entryoffset, fd->entrylength);
110                 hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
111         }
112
113         /*
114          * We can't just use hfsplus_mark_inode_dirty here, because we
115          * also get called from hfsplus_write_inode, which should not
116          * redirty the inode.  Instead the callers have to be careful
117          * to explicily mark the inode dirty, too.
118          */
119         set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
120 }
121
122 static int hfsplus_ext_write_extent_locked(struct inode *inode)
123 {
124         int res;
125
126         if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
127                 struct hfs_find_data fd;
128
129                 res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
130                 if (res)
131                         return res;
132                 __hfsplus_ext_write_extent(inode, &fd);
133                 hfs_find_exit(&fd);
134         }
135         return 0;
136 }
137
138 int hfsplus_ext_write_extent(struct inode *inode)
139 {
140         int res;
141
142         mutex_lock(&HFSPLUS_I(inode)->extents_lock);
143         res = hfsplus_ext_write_extent_locked(inode);
144         mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
145
146         return res;
147 }
148
149 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
150                                             struct hfsplus_extent *extent,
151                                             u32 cnid, u32 block, u8 type)
152 {
153         int res;
154
155         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
156         fd->key->ext.cnid = 0;
157         res = hfs_brec_find(fd);
158         if (res && res != -ENOENT)
159                 return res;
160         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
161             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
162                 return -ENOENT;
163         if (fd->entrylength != sizeof(hfsplus_extent_rec))
164                 return -EIO;
165         hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
166                 sizeof(hfsplus_extent_rec));
167         return 0;
168 }
169
170 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
171                 struct inode *inode, u32 block)
172 {
173         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
174         int res;
175
176         WARN_ON(!mutex_is_locked(&hip->extents_lock));
177
178         if (hip->extent_state & HFSPLUS_EXT_DIRTY)
179                 __hfsplus_ext_write_extent(inode, fd);
180
181         res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
182                                         block, HFSPLUS_IS_RSRC(inode) ?
183                                                 HFSPLUS_TYPE_RSRC :
184                                                 HFSPLUS_TYPE_DATA);
185         if (!res) {
186                 hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
187                 hip->cached_blocks =
188                         hfsplus_ext_block_count(hip->cached_extents);
189         } else {
190                 hip->cached_start = hip->cached_blocks = 0;
191                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
192         }
193         return res;
194 }
195
196 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
197 {
198         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
199         struct hfs_find_data fd;
200         int res;
201
202         if (block >= hip->cached_start &&
203             block < hip->cached_start + hip->cached_blocks)
204                 return 0;
205
206         res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
207         if (!res) {
208                 res = __hfsplus_ext_cache_extent(&fd, inode, block);
209                 hfs_find_exit(&fd);
210         }
211         return res;
212 }
213
214 /* Get a block at iblock for inode, possibly allocating if create */
215 int hfsplus_get_block(struct inode *inode, sector_t iblock,
216                       struct buffer_head *bh_result, int create)
217 {
218         struct super_block *sb = inode->i_sb;
219         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
220         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
221         int res = -EIO;
222         u32 ablock, dblock, mask;
223         sector_t sector;
224         int was_dirty = 0;
225         int shift;
226
227         /* Convert inode block to disk allocation block */
228         shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
229         ablock = iblock >> sbi->fs_shift;
230
231         if (iblock >= hip->fs_blocks) {
232                 if (iblock > hip->fs_blocks || !create)
233                         return -EIO;
234                 if (ablock >= hip->alloc_blocks) {
235                         res = hfsplus_file_extend(inode);
236                         if (res)
237                                 return res;
238                 }
239         } else
240                 create = 0;
241
242         if (ablock < hip->first_blocks) {
243                 dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
244                 goto done;
245         }
246
247         if (inode->i_ino == HFSPLUS_EXT_CNID)
248                 return -EIO;
249
250         mutex_lock(&hip->extents_lock);
251
252         /*
253          * hfsplus_ext_read_extent will write out a cached extent into
254          * the extents btree.  In that case we may have to mark the inode
255          * dirty even for a pure read of an extent here.
256          */
257         was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
258         res = hfsplus_ext_read_extent(inode, ablock);
259         if (res) {
260                 mutex_unlock(&hip->extents_lock);
261                 return -EIO;
262         }
263         dblock = hfsplus_ext_find_block(hip->cached_extents,
264                                         ablock - hip->cached_start);
265         mutex_unlock(&hip->extents_lock);
266
267 done:
268         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n",
269                 inode->i_ino, (long long)iblock, dblock);
270
271         mask = (1 << sbi->fs_shift) - 1;
272         sector = ((sector_t)dblock << sbi->fs_shift) +
273                   sbi->blockoffset + (iblock & mask);
274         map_bh(bh_result, sb, sector);
275
276         if (create) {
277                 set_buffer_new(bh_result);
278                 hip->phys_size += sb->s_blocksize;
279                 hip->fs_blocks++;
280                 inode_add_bytes(inode, sb->s_blocksize);
281         }
282         if (create || was_dirty)
283                 mark_inode_dirty(inode);
284         return 0;
285 }
286
287 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
288 {
289         int i;
290
291         dprint(DBG_EXTENT, "   ");
292         for (i = 0; i < 8; i++)
293                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
294                                  be32_to_cpu(extent[i].block_count));
295         dprint(DBG_EXTENT, "\n");
296 }
297
298 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
299                               u32 alloc_block, u32 block_count)
300 {
301         u32 count, start;
302         int i;
303
304         hfsplus_dump_extent(extent);
305         for (i = 0; i < 8; extent++, i++) {
306                 count = be32_to_cpu(extent->block_count);
307                 if (offset == count) {
308                         start = be32_to_cpu(extent->start_block);
309                         if (alloc_block != start + count) {
310                                 if (++i >= 8)
311                                         return -ENOSPC;
312                                 extent++;
313                                 extent->start_block = cpu_to_be32(alloc_block);
314                         } else
315                                 block_count += count;
316                         extent->block_count = cpu_to_be32(block_count);
317                         return 0;
318                 } else if (offset < count)
319                         break;
320                 offset -= count;
321         }
322         /* panic? */
323         return -EIO;
324 }
325
326 static int hfsplus_free_extents(struct super_block *sb,
327                                 struct hfsplus_extent *extent,
328                                 u32 offset, u32 block_nr)
329 {
330         u32 count, start;
331         int i;
332         int err = 0;
333
334         hfsplus_dump_extent(extent);
335         for (i = 0; i < 8; extent++, i++) {
336                 count = be32_to_cpu(extent->block_count);
337                 if (offset == count)
338                         goto found;
339                 else if (offset < count)
340                         break;
341                 offset -= count;
342         }
343         /* panic? */
344         return -EIO;
345 found:
346         for (;;) {
347                 start = be32_to_cpu(extent->start_block);
348                 if (count <= block_nr) {
349                         err = hfsplus_block_free(sb, start, count);
350                         if (err) {
351                                 printk(KERN_ERR "hfs: can't free extent\n");
352                                 dprint(DBG_EXTENT, " start: %u count: %u\n",
353                                         start, count);
354                         }
355                         extent->block_count = 0;
356                         extent->start_block = 0;
357                         block_nr -= count;
358                 } else {
359                         count -= block_nr;
360                         err = hfsplus_block_free(sb, start + count, block_nr);
361                         if (err) {
362                                 printk(KERN_ERR "hfs: can't free extent\n");
363                                 dprint(DBG_EXTENT, " start: %u count: %u\n",
364                                         start, count);
365                         }
366                         extent->block_count = cpu_to_be32(count);
367                         block_nr = 0;
368                 }
369                 if (!block_nr || !i) {
370                         /*
371                          * Try to free all extents and
372                          * return only last error
373                          */
374                         return err;
375                 }
376                 i--;
377                 extent--;
378                 count = be32_to_cpu(extent->block_count);
379         }
380 }
381
382 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
383                 struct hfsplus_fork_raw *fork, int type)
384 {
385         struct hfs_find_data fd;
386         hfsplus_extent_rec ext_entry;
387         u32 total_blocks, blocks, start;
388         int res, i;
389
390         total_blocks = be32_to_cpu(fork->total_blocks);
391         if (!total_blocks)
392                 return 0;
393
394         blocks = 0;
395         for (i = 0; i < 8; i++)
396                 blocks += be32_to_cpu(fork->extents[i].block_count);
397
398         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
399         if (res)
400                 return res;
401         if (total_blocks == blocks)
402                 return 0;
403
404         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
405         if (res)
406                 return res;
407         do {
408                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
409                                                 total_blocks, type);
410                 if (res)
411                         break;
412                 start = be32_to_cpu(fd.key->ext.start_block);
413                 hfsplus_free_extents(sb, ext_entry,
414                                      total_blocks - start,
415                                      total_blocks);
416                 hfs_brec_remove(&fd);
417                 total_blocks = start;
418         } while (total_blocks > blocks);
419         hfs_find_exit(&fd);
420
421         return res;
422 }
423
424 int hfsplus_file_extend(struct inode *inode)
425 {
426         struct super_block *sb = inode->i_sb;
427         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
428         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
429         u32 start, len, goal;
430         int res;
431
432         if (sbi->alloc_file->i_size * 8 <
433             sbi->total_blocks - sbi->free_blocks + 8) {
434                 /* extend alloc file */
435                 printk(KERN_ERR "hfs: extend alloc file! "
436                                 "(%llu,%u,%u)\n",
437                         sbi->alloc_file->i_size * 8,
438                         sbi->total_blocks, sbi->free_blocks);
439                 return -ENOSPC;
440         }
441
442         mutex_lock(&hip->extents_lock);
443         if (hip->alloc_blocks == hip->first_blocks)
444                 goal = hfsplus_ext_lastblock(hip->first_extents);
445         else {
446                 res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
447                 if (res)
448                         goto out;
449                 goal = hfsplus_ext_lastblock(hip->cached_extents);
450         }
451
452         len = hip->clump_blocks;
453         start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
454         if (start >= sbi->total_blocks) {
455                 start = hfsplus_block_allocate(sb, goal, 0, &len);
456                 if (start >= goal) {
457                         res = -ENOSPC;
458                         goto out;
459                 }
460         }
461
462         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
463
464         if (hip->alloc_blocks <= hip->first_blocks) {
465                 if (!hip->first_blocks) {
466                         dprint(DBG_EXTENT, "first extents\n");
467                         /* no extents yet */
468                         hip->first_extents[0].start_block = cpu_to_be32(start);
469                         hip->first_extents[0].block_count = cpu_to_be32(len);
470                         res = 0;
471                 } else {
472                         /* try to append to extents in inode */
473                         res = hfsplus_add_extent(hip->first_extents,
474                                                  hip->alloc_blocks,
475                                                  start, len);
476                         if (res == -ENOSPC)
477                                 goto insert_extent;
478                 }
479                 if (!res) {
480                         hfsplus_dump_extent(hip->first_extents);
481                         hip->first_blocks += len;
482                 }
483         } else {
484                 res = hfsplus_add_extent(hip->cached_extents,
485                                          hip->alloc_blocks - hip->cached_start,
486                                          start, len);
487                 if (!res) {
488                         hfsplus_dump_extent(hip->cached_extents);
489                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
490                         hip->cached_blocks += len;
491                 } else if (res == -ENOSPC)
492                         goto insert_extent;
493         }
494 out:
495         mutex_unlock(&hip->extents_lock);
496         if (!res) {
497                 hip->alloc_blocks += len;
498                 hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
499         }
500         return res;
501
502 insert_extent:
503         dprint(DBG_EXTENT, "insert new extent\n");
504         res = hfsplus_ext_write_extent_locked(inode);
505         if (res)
506                 goto out;
507
508         memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
509         hip->cached_extents[0].start_block = cpu_to_be32(start);
510         hip->cached_extents[0].block_count = cpu_to_be32(len);
511         hfsplus_dump_extent(hip->cached_extents);
512         hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
513         hip->cached_start = hip->alloc_blocks;
514         hip->cached_blocks = len;
515
516         res = 0;
517         goto out;
518 }
519
520 void hfsplus_file_truncate(struct inode *inode)
521 {
522         struct super_block *sb = inode->i_sb;
523         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
524         struct hfs_find_data fd;
525         u32 alloc_cnt, blk_cnt, start;
526         int res;
527
528         dprint(DBG_INODE, "truncate: %lu, %llu -> %llu\n",
529                 inode->i_ino, (long long)hip->phys_size,
530                 inode->i_size);
531
532         if (inode->i_size > hip->phys_size) {
533                 struct address_space *mapping = inode->i_mapping;
534                 struct page *page;
535                 void *fsdata;
536                 u32 size = inode->i_size;
537
538                 res = pagecache_write_begin(NULL, mapping, size, 0,
539                                                 AOP_FLAG_UNINTERRUPTIBLE,
540                                                 &page, &fsdata);
541                 if (res)
542                         return;
543                 res = pagecache_write_end(NULL, mapping, size,
544                         0, 0, page, fsdata);
545                 if (res < 0)
546                         return;
547                 mark_inode_dirty(inode);
548                 return;
549         } else if (inode->i_size == hip->phys_size)
550                 return;
551
552         blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
553                         HFSPLUS_SB(sb)->alloc_blksz_shift;
554         alloc_cnt = hip->alloc_blocks;
555         if (blk_cnt == alloc_cnt)
556                 goto out;
557
558         mutex_lock(&hip->extents_lock);
559         res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
560         if (res) {
561                 mutex_unlock(&hip->extents_lock);
562                 /* XXX: We lack error handling of hfsplus_file_truncate() */
563                 return;
564         }
565         while (1) {
566                 if (alloc_cnt == hip->first_blocks) {
567                         hfsplus_free_extents(sb, hip->first_extents,
568                                              alloc_cnt, alloc_cnt - blk_cnt);
569                         hfsplus_dump_extent(hip->first_extents);
570                         hip->first_blocks = blk_cnt;
571                         break;
572                 }
573                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
574                 if (res)
575                         break;
576                 start = hip->cached_start;
577                 hfsplus_free_extents(sb, hip->cached_extents,
578                                      alloc_cnt - start, alloc_cnt - blk_cnt);
579                 hfsplus_dump_extent(hip->cached_extents);
580                 if (blk_cnt > start) {
581                         hip->extent_state |= HFSPLUS_EXT_DIRTY;
582                         break;
583                 }
584                 alloc_cnt = start;
585                 hip->cached_start = hip->cached_blocks = 0;
586                 hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
587                 hfs_brec_remove(&fd);
588         }
589         hfs_find_exit(&fd);
590         mutex_unlock(&hip->extents_lock);
591
592         hip->alloc_blocks = blk_cnt;
593 out:
594         hip->phys_size = inode->i_size;
595         hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
596                 sb->s_blocksize_bits;
597         inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
598         hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
599 }