Merge branch 'for-linus' of git://neil.brown.name/md
[linux-2.6] / fs / hfsplus / extents.c
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, struct hfs_find_data *fd)
87 {
88         int res;
89
90         hfsplus_ext_build_key(fd->search_key, inode->i_ino, HFSPLUS_I(inode).cached_start,
91                               HFSPLUS_IS_RSRC(inode) ?  HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
92         res = hfs_brec_find(fd);
93         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_NEW) {
94                 if (res != -ENOENT)
95                         return;
96                 hfs_brec_insert(fd, HFSPLUS_I(inode).cached_extents, sizeof(hfsplus_extent_rec));
97                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
98         } else {
99                 if (res)
100                         return;
101                 hfs_bnode_write(fd->bnode, HFSPLUS_I(inode).cached_extents, fd->entryoffset, fd->entrylength);
102                 HFSPLUS_I(inode).flags &= ~HFSPLUS_FLG_EXT_DIRTY;
103         }
104 }
105
106 void hfsplus_ext_write_extent(struct inode *inode)
107 {
108         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY) {
109                 struct hfs_find_data fd;
110
111                 hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
112                 __hfsplus_ext_write_extent(inode, &fd);
113                 hfs_find_exit(&fd);
114         }
115 }
116
117 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
118                                             struct hfsplus_extent *extent,
119                                             u32 cnid, u32 block, u8 type)
120 {
121         int res;
122
123         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
124         fd->key->ext.cnid = 0;
125         res = hfs_brec_find(fd);
126         if (res && res != -ENOENT)
127                 return res;
128         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
129             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
130                 return -ENOENT;
131         if (fd->entrylength != sizeof(hfsplus_extent_rec))
132                 return -EIO;
133         hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfsplus_extent_rec));
134         return 0;
135 }
136
137 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
138 {
139         int res;
140
141         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY)
142                 __hfsplus_ext_write_extent(inode, fd);
143
144         res = __hfsplus_ext_read_extent(fd, HFSPLUS_I(inode).cached_extents, inode->i_ino,
145                                         block, HFSPLUS_IS_RSRC(inode) ? HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
146         if (!res) {
147                 HFSPLUS_I(inode).cached_start = be32_to_cpu(fd->key->ext.start_block);
148                 HFSPLUS_I(inode).cached_blocks = hfsplus_ext_block_count(HFSPLUS_I(inode).cached_extents);
149         } else {
150                 HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
151                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
152         }
153         return res;
154 }
155
156 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
157 {
158         struct hfs_find_data fd;
159         int res;
160
161         if (block >= HFSPLUS_I(inode).cached_start &&
162             block < HFSPLUS_I(inode).cached_start + HFSPLUS_I(inode).cached_blocks)
163                 return 0;
164
165         hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
166         res = __hfsplus_ext_cache_extent(&fd, inode, block);
167         hfs_find_exit(&fd);
168         return res;
169 }
170
171 /* Get a block at iblock for inode, possibly allocating if create */
172 int hfsplus_get_block(struct inode *inode, sector_t iblock,
173                       struct buffer_head *bh_result, int create)
174 {
175         struct super_block *sb;
176         int res = -EIO;
177         u32 ablock, dblock, mask;
178         int shift;
179
180         sb = inode->i_sb;
181
182         /* Convert inode block to disk allocation block */
183         shift = HFSPLUS_SB(sb).alloc_blksz_shift - sb->s_blocksize_bits;
184         ablock = iblock >> HFSPLUS_SB(sb).fs_shift;
185
186         if (iblock >= HFSPLUS_I(inode).fs_blocks) {
187                 if (iblock > HFSPLUS_I(inode).fs_blocks || !create)
188                         return -EIO;
189                 if (ablock >= HFSPLUS_I(inode).alloc_blocks) {
190                         res = hfsplus_file_extend(inode);
191                         if (res)
192                                 return res;
193                 }
194         } else
195                 create = 0;
196
197         if (ablock < HFSPLUS_I(inode).first_blocks) {
198                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).first_extents, ablock);
199                 goto done;
200         }
201
202         mutex_lock(&HFSPLUS_I(inode).extents_lock);
203         res = hfsplus_ext_read_extent(inode, ablock);
204         if (!res) {
205                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).cached_extents, ablock -
206                                              HFSPLUS_I(inode).cached_start);
207         } else {
208                 mutex_unlock(&HFSPLUS_I(inode).extents_lock);
209                 return -EIO;
210         }
211         mutex_unlock(&HFSPLUS_I(inode).extents_lock);
212
213 done:
214         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
215         mask = (1 << HFSPLUS_SB(sb).fs_shift) - 1;
216         map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));
217         if (create) {
218                 set_buffer_new(bh_result);
219                 HFSPLUS_I(inode).phys_size += sb->s_blocksize;
220                 HFSPLUS_I(inode).fs_blocks++;
221                 inode_add_bytes(inode, sb->s_blocksize);
222                 mark_inode_dirty(inode);
223         }
224         return 0;
225 }
226
227 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
228 {
229         int i;
230
231         dprint(DBG_EXTENT, "   ");
232         for (i = 0; i < 8; i++)
233                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
234                                  be32_to_cpu(extent[i].block_count));
235         dprint(DBG_EXTENT, "\n");
236 }
237
238 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
239                               u32 alloc_block, u32 block_count)
240 {
241         u32 count, start;
242         int i;
243
244         hfsplus_dump_extent(extent);
245         for (i = 0; i < 8; extent++, i++) {
246                 count = be32_to_cpu(extent->block_count);
247                 if (offset == count) {
248                         start = be32_to_cpu(extent->start_block);
249                         if (alloc_block != start + count) {
250                                 if (++i >= 8)
251                                         return -ENOSPC;
252                                 extent++;
253                                 extent->start_block = cpu_to_be32(alloc_block);
254                         } else
255                                 block_count += count;
256                         extent->block_count = cpu_to_be32(block_count);
257                         return 0;
258                 } else if (offset < count)
259                         break;
260                 offset -= count;
261         }
262         /* panic? */
263         return -EIO;
264 }
265
266 static int hfsplus_free_extents(struct super_block *sb,
267                                 struct hfsplus_extent *extent,
268                                 u32 offset, u32 block_nr)
269 {
270         u32 count, start;
271         int i;
272
273         hfsplus_dump_extent(extent);
274         for (i = 0; i < 8; extent++, i++) {
275                 count = be32_to_cpu(extent->block_count);
276                 if (offset == count)
277                         goto found;
278                 else if (offset < count)
279                         break;
280                 offset -= count;
281         }
282         /* panic? */
283         return -EIO;
284 found:
285         for (;;) {
286                 start = be32_to_cpu(extent->start_block);
287                 if (count <= block_nr) {
288                         hfsplus_block_free(sb, start, count);
289                         extent->block_count = 0;
290                         extent->start_block = 0;
291                         block_nr -= count;
292                 } else {
293                         count -= block_nr;
294                         hfsplus_block_free(sb, start + count, block_nr);
295                         extent->block_count = cpu_to_be32(count);
296                         block_nr = 0;
297                 }
298                 if (!block_nr || !i)
299                         return 0;
300                 i--;
301                 extent--;
302                 count = be32_to_cpu(extent->block_count);
303         }
304 }
305
306 int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
307 {
308         struct hfs_find_data fd;
309         hfsplus_extent_rec ext_entry;
310         u32 total_blocks, blocks, start;
311         int res, i;
312
313         total_blocks = be32_to_cpu(fork->total_blocks);
314         if (!total_blocks)
315                 return 0;
316
317         blocks = 0;
318         for (i = 0; i < 8; i++)
319                 blocks += be32_to_cpu(fork->extents[i].block_count);
320
321         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
322         if (res)
323                 return res;
324         if (total_blocks == blocks)
325                 return 0;
326
327         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
328         do {
329                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
330                                                 total_blocks, type);
331                 if (res)
332                         break;
333                 start = be32_to_cpu(fd.key->ext.start_block);
334                 hfsplus_free_extents(sb, ext_entry,
335                                      total_blocks - start,
336                                      total_blocks);
337                 hfs_brec_remove(&fd);
338                 total_blocks = start;
339         } while (total_blocks > blocks);
340         hfs_find_exit(&fd);
341
342         return res;
343 }
344
345 int hfsplus_file_extend(struct inode *inode)
346 {
347         struct super_block *sb = inode->i_sb;
348         u32 start, len, goal;
349         int res;
350
351         if (HFSPLUS_SB(sb).alloc_file->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
352                 // extend alloc file
353                 printk(KERN_ERR "hfs: extend alloc file! (%Lu,%u,%u)\n", HFSPLUS_SB(sb).alloc_file->i_size * 8,
354                         HFSPLUS_SB(sb).total_blocks, HFSPLUS_SB(sb).free_blocks);
355                 return -ENOSPC;
356         }
357
358         mutex_lock(&HFSPLUS_I(inode).extents_lock);
359         if (HFSPLUS_I(inode).alloc_blocks == HFSPLUS_I(inode).first_blocks)
360                 goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).first_extents);
361         else {
362                 res = hfsplus_ext_read_extent(inode, HFSPLUS_I(inode).alloc_blocks);
363                 if (res)
364                         goto out;
365                 goal = hfsplus_ext_lastblock(HFSPLUS_I(inode).cached_extents);
366         }
367
368         len = HFSPLUS_I(inode).clump_blocks;
369         start = hfsplus_block_allocate(sb, HFSPLUS_SB(sb).total_blocks, goal, &len);
370         if (start >= HFSPLUS_SB(sb).total_blocks) {
371                 start = hfsplus_block_allocate(sb, goal, 0, &len);
372                 if (start >= goal) {
373                         res = -ENOSPC;
374                         goto out;
375                 }
376         }
377
378         dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
379         if (HFSPLUS_I(inode).alloc_blocks <= HFSPLUS_I(inode).first_blocks) {
380                 if (!HFSPLUS_I(inode).first_blocks) {
381                         dprint(DBG_EXTENT, "first extents\n");
382                         /* no extents yet */
383                         HFSPLUS_I(inode).first_extents[0].start_block = cpu_to_be32(start);
384                         HFSPLUS_I(inode).first_extents[0].block_count = cpu_to_be32(len);
385                         res = 0;
386                 } else {
387                         /* try to append to extents in inode */
388                         res = hfsplus_add_extent(HFSPLUS_I(inode).first_extents,
389                                                  HFSPLUS_I(inode).alloc_blocks,
390                                                  start, len);
391                         if (res == -ENOSPC)
392                                 goto insert_extent;
393                 }
394                 if (!res) {
395                         hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
396                         HFSPLUS_I(inode).first_blocks += len;
397                 }
398         } else {
399                 res = hfsplus_add_extent(HFSPLUS_I(inode).cached_extents,
400                                          HFSPLUS_I(inode).alloc_blocks -
401                                          HFSPLUS_I(inode).cached_start,
402                                          start, len);
403                 if (!res) {
404                         hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
405                         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
406                         HFSPLUS_I(inode).cached_blocks += len;
407                 } else if (res == -ENOSPC)
408                         goto insert_extent;
409         }
410 out:
411         mutex_unlock(&HFSPLUS_I(inode).extents_lock);
412         if (!res) {
413                 HFSPLUS_I(inode).alloc_blocks += len;
414                 mark_inode_dirty(inode);
415         }
416         return res;
417
418 insert_extent:
419         dprint(DBG_EXTENT, "insert new extent\n");
420         hfsplus_ext_write_extent(inode);
421
422         memset(HFSPLUS_I(inode).cached_extents, 0, sizeof(hfsplus_extent_rec));
423         HFSPLUS_I(inode).cached_extents[0].start_block = cpu_to_be32(start);
424         HFSPLUS_I(inode).cached_extents[0].block_count = cpu_to_be32(len);
425         hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
426         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW;
427         HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).alloc_blocks;
428         HFSPLUS_I(inode).cached_blocks = len;
429
430         res = 0;
431         goto out;
432 }
433
434 void hfsplus_file_truncate(struct inode *inode)
435 {
436         struct super_block *sb = inode->i_sb;
437         struct hfs_find_data fd;
438         u32 alloc_cnt, blk_cnt, start;
439         int res;
440
441         dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
442                (long long)HFSPLUS_I(inode).phys_size, inode->i_size);
443         if (inode->i_size > HFSPLUS_I(inode).phys_size) {
444                 struct address_space *mapping = inode->i_mapping;
445                 struct page *page;
446                 void *fsdata;
447                 u32 size = inode->i_size;
448                 int res;
449
450                 res = pagecache_write_begin(NULL, mapping, size, 0,
451                                                 AOP_FLAG_UNINTERRUPTIBLE,
452                                                 &page, &fsdata);
453                 if (res)
454                         return;
455                 res = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata);
456                 if (res < 0)
457                         return;
458                 mark_inode_dirty(inode);
459                 return;
460         } else if (inode->i_size == HFSPLUS_I(inode).phys_size)
461                 return;
462
463         blk_cnt = (inode->i_size + HFSPLUS_SB(sb).alloc_blksz - 1) >> HFSPLUS_SB(sb).alloc_blksz_shift;
464         alloc_cnt = HFSPLUS_I(inode).alloc_blocks;
465         if (blk_cnt == alloc_cnt)
466                 goto out;
467
468         mutex_lock(&HFSPLUS_I(inode).extents_lock);
469         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
470         while (1) {
471                 if (alloc_cnt == HFSPLUS_I(inode).first_blocks) {
472                         hfsplus_free_extents(sb, HFSPLUS_I(inode).first_extents,
473                                              alloc_cnt, alloc_cnt - blk_cnt);
474                         hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
475                         HFSPLUS_I(inode).first_blocks = blk_cnt;
476                         break;
477                 }
478                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
479                 if (res)
480                         break;
481                 start = HFSPLUS_I(inode).cached_start;
482                 hfsplus_free_extents(sb, HFSPLUS_I(inode).cached_extents,
483                                      alloc_cnt - start, alloc_cnt - blk_cnt);
484                 hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
485                 if (blk_cnt > start) {
486                         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
487                         break;
488                 }
489                 alloc_cnt = start;
490                 HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
491                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
492                 hfs_brec_remove(&fd);
493         }
494         hfs_find_exit(&fd);
495         mutex_unlock(&HFSPLUS_I(inode).extents_lock);
496
497         HFSPLUS_I(inode).alloc_blocks = blk_cnt;
498 out:
499         HFSPLUS_I(inode).phys_size = inode->i_size;
500         HFSPLUS_I(inode).fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
501         inode_set_bytes(inode, HFSPLUS_I(inode).fs_blocks << sb->s_blocksize_bits);
502         mark_inode_dirty(inode);
503 }