Merge ../linux-2.6
[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(hfsplus_btree_key *k1, hfsplus_btree_key *k2)
20 {
21         __be32 k1id, k2id;
22         __be32 k1s, k2s;
23
24         k1id = k1->ext.cnid;
25         k2id = k2->ext.cnid;
26         if (k1id != k2id)
27                 return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
28
29         if (k1->ext.fork_type != k2->ext.fork_type)
30                 return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
31
32         k1s = k1->ext.start_block;
33         k2s = k2->ext.start_block;
34         if (k1s == k2s)
35                 return 0;
36         return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
37 }
38
39 static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
40                                   u32 block, u8 type)
41 {
42         key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
43         key->ext.cnid = cpu_to_be32(cnid);
44         key->ext.start_block = cpu_to_be32(block);
45         key->ext.fork_type = type;
46         key->ext.pad = 0;
47 }
48
49 static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
50 {
51         int i;
52         u32 count;
53
54         for (i = 0; i < 8; ext++, i++) {
55                 count = be32_to_cpu(ext->block_count);
56                 if (off < count)
57                         return be32_to_cpu(ext->start_block) + off;
58                 off -= count;
59         }
60         /* panic? */
61         return 0;
62 }
63
64 static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
65 {
66         int i;
67         u32 count = 0;
68
69         for (i = 0; i < 8; ext++, i++)
70                 count += be32_to_cpu(ext->block_count);
71         return count;
72 }
73
74 static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
75 {
76         int i;
77
78         ext += 7;
79         for (i = 0; i < 7; ext--, i++)
80                 if (ext->block_count)
81                         break;
82         return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
83 }
84
85 static void __hfsplus_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
86 {
87         int res;
88
89         hfsplus_ext_build_key(fd->search_key, inode->i_ino, HFSPLUS_I(inode).cached_start,
90                               HFSPLUS_IS_RSRC(inode) ?  HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
91         res = hfs_brec_find(fd);
92         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_NEW) {
93                 if (res != -ENOENT)
94                         return;
95                 hfs_brec_insert(fd, HFSPLUS_I(inode).cached_extents, sizeof(hfsplus_extent_rec));
96                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
97         } else {
98                 if (res)
99                         return;
100                 hfs_bnode_write(fd->bnode, HFSPLUS_I(inode).cached_extents, fd->entryoffset, fd->entrylength);
101                 HFSPLUS_I(inode).flags &= ~HFSPLUS_FLG_EXT_DIRTY;
102         }
103 }
104
105 void hfsplus_ext_write_extent(struct inode *inode)
106 {
107         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY) {
108                 struct hfs_find_data fd;
109
110                 hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
111                 __hfsplus_ext_write_extent(inode, &fd);
112                 hfs_find_exit(&fd);
113         }
114 }
115
116 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
117                                             struct hfsplus_extent *extent,
118                                             u32 cnid, u32 block, u8 type)
119 {
120         int res;
121
122         hfsplus_ext_build_key(fd->search_key, cnid, block, type);
123         fd->key->ext.cnid = 0;
124         res = hfs_brec_find(fd);
125         if (res && res != -ENOENT)
126                 return res;
127         if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
128             fd->key->ext.fork_type != fd->search_key->ext.fork_type)
129                 return -ENOENT;
130         if (fd->entrylength != sizeof(hfsplus_extent_rec))
131                 return -EIO;
132         hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfsplus_extent_rec));
133         return 0;
134 }
135
136 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
137 {
138         int res;
139
140         if (HFSPLUS_I(inode).flags & HFSPLUS_FLG_EXT_DIRTY)
141                 __hfsplus_ext_write_extent(inode, fd);
142
143         res = __hfsplus_ext_read_extent(fd, HFSPLUS_I(inode).cached_extents, inode->i_ino,
144                                         block, HFSPLUS_IS_RSRC(inode) ? HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
145         if (!res) {
146                 HFSPLUS_I(inode).cached_start = be32_to_cpu(fd->key->ext.start_block);
147                 HFSPLUS_I(inode).cached_blocks = hfsplus_ext_block_count(HFSPLUS_I(inode).cached_extents);
148         } else {
149                 HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
150                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
151         }
152         return res;
153 }
154
155 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
156 {
157         struct hfs_find_data fd;
158         int res;
159
160         if (block >= HFSPLUS_I(inode).cached_start &&
161             block < HFSPLUS_I(inode).cached_start + HFSPLUS_I(inode).cached_blocks)
162                 return 0;
163
164         hfs_find_init(HFSPLUS_SB(inode->i_sb).ext_tree, &fd);
165         res = __hfsplus_ext_cache_extent(&fd, inode, block);
166         hfs_find_exit(&fd);
167         return res;
168 }
169
170 /* Get a block at iblock for inode, possibly allocating if create */
171 int hfsplus_get_block(struct inode *inode, sector_t iblock,
172                       struct buffer_head *bh_result, int create)
173 {
174         struct super_block *sb;
175         int res = -EIO;
176         u32 ablock, dblock, mask;
177         int shift;
178
179         sb = inode->i_sb;
180
181         /* Convert inode block to disk allocation block */
182         shift = HFSPLUS_SB(sb).alloc_blksz_shift - sb->s_blocksize_bits;
183         ablock = iblock >> HFSPLUS_SB(sb).fs_shift;
184
185         if (iblock >= HFSPLUS_I(inode).fs_blocks) {
186                 if (iblock > HFSPLUS_I(inode).fs_blocks || !create)
187                         return -EIO;
188                 if (ablock >= HFSPLUS_I(inode).alloc_blocks) {
189                         res = hfsplus_file_extend(inode);
190                         if (res)
191                                 return res;
192                 }
193         } else
194                 create = 0;
195
196         if (ablock < HFSPLUS_I(inode).first_blocks) {
197                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).first_extents, ablock);
198                 goto done;
199         }
200
201         down(&HFSPLUS_I(inode).extents_lock);
202         res = hfsplus_ext_read_extent(inode, ablock);
203         if (!res) {
204                 dblock = hfsplus_ext_find_block(HFSPLUS_I(inode).cached_extents, ablock -
205                                              HFSPLUS_I(inode).cached_start);
206         } else {
207                 up(&HFSPLUS_I(inode).extents_lock);
208                 return -EIO;
209         }
210         up(&HFSPLUS_I(inode).extents_lock);
211
212 done:
213         dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n", inode->i_ino, (long long)iblock, dblock);
214         mask = (1 << HFSPLUS_SB(sb).fs_shift) - 1;
215         map_bh(bh_result, sb, (dblock << HFSPLUS_SB(sb).fs_shift) + HFSPLUS_SB(sb).blockoffset + (iblock & mask));
216         if (create) {
217                 set_buffer_new(bh_result);
218                 HFSPLUS_I(inode).phys_size += sb->s_blocksize;
219                 HFSPLUS_I(inode).fs_blocks++;
220                 inode_add_bytes(inode, sb->s_blocksize);
221                 mark_inode_dirty(inode);
222         }
223         return 0;
224 }
225
226 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
227 {
228         int i;
229
230         dprint(DBG_EXTENT, "   ");
231         for (i = 0; i < 8; i++)
232                 dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
233                                  be32_to_cpu(extent[i].block_count));
234         dprint(DBG_EXTENT, "\n");
235 }
236
237 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
238                               u32 alloc_block, u32 block_count)
239 {
240         u32 count, start;
241         int i;
242
243         hfsplus_dump_extent(extent);
244         for (i = 0; i < 8; extent++, i++) {
245                 count = be32_to_cpu(extent->block_count);
246                 if (offset == count) {
247                         start = be32_to_cpu(extent->start_block);
248                         if (alloc_block != start + count) {
249                                 if (++i >= 8)
250                                         return -ENOSPC;
251                                 extent++;
252                                 extent->start_block = cpu_to_be32(alloc_block);
253                         } else
254                                 block_count += count;
255                         extent->block_count = cpu_to_be32(block_count);
256                         return 0;
257                 } else if (offset < count)
258                         break;
259                 offset -= count;
260         }
261         /* panic? */
262         return -EIO;
263 }
264
265 static int hfsplus_free_extents(struct super_block *sb,
266                                 struct hfsplus_extent *extent,
267                                 u32 offset, u32 block_nr)
268 {
269         u32 count, start;
270         int i;
271
272         hfsplus_dump_extent(extent);
273         for (i = 0; i < 8; extent++, i++) {
274                 count = be32_to_cpu(extent->block_count);
275                 if (offset == count)
276                         goto found;
277                 else if (offset < count)
278                         break;
279                 offset -= count;
280         }
281         /* panic? */
282         return -EIO;
283 found:
284         for (;;) {
285                 start = be32_to_cpu(extent->start_block);
286                 if (count <= block_nr) {
287                         hfsplus_block_free(sb, start, count);
288                         extent->block_count = 0;
289                         extent->start_block = 0;
290                         block_nr -= count;
291                 } else {
292                         count -= block_nr;
293                         hfsplus_block_free(sb, start + count, block_nr);
294                         extent->block_count = cpu_to_be32(count);
295                         block_nr = 0;
296                 }
297                 if (!block_nr || !i)
298                         return 0;
299                 i--;
300                 extent--;
301                 count = be32_to_cpu(extent->block_count);
302         }
303 }
304
305 int hfsplus_free_fork(struct super_block *sb, u32 cnid, struct hfsplus_fork_raw *fork, int type)
306 {
307         struct hfs_find_data fd;
308         hfsplus_extent_rec ext_entry;
309         u32 total_blocks, blocks, start;
310         int res, i;
311
312         total_blocks = be32_to_cpu(fork->total_blocks);
313         if (!total_blocks)
314                 return 0;
315
316         blocks = 0;
317         for (i = 0; i < 8; i++)
318                 blocks += be32_to_cpu(fork->extents[i].block_count);
319
320         res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
321         if (res)
322                 return res;
323         if (total_blocks == blocks)
324                 return 0;
325
326         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
327         do {
328                 res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
329                                                 total_blocks, type);
330                 if (res)
331                         break;
332                 start = be32_to_cpu(fd.key->ext.start_block);
333                 hfsplus_free_extents(sb, ext_entry,
334                                      total_blocks - start,
335                                      total_blocks);
336                 hfs_brec_remove(&fd);
337                 total_blocks = start;
338         } while (total_blocks > blocks);
339         hfs_find_exit(&fd);
340
341         return res;
342 }
343
344 int hfsplus_file_extend(struct inode *inode)
345 {
346         struct super_block *sb = inode->i_sb;
347         u32 start, len, goal;
348         int res;
349
350         if (HFSPLUS_SB(sb).alloc_file->i_size * 8 < HFSPLUS_SB(sb).total_blocks - HFSPLUS_SB(sb).free_blocks + 8) {
351                 // extend alloc file
352                 printk("extend alloc file! (%Lu,%u,%u)\n", HFSPLUS_SB(sb).alloc_file->i_size * 8,
353                         HFSPLUS_SB(sb).total_blocks, HFSPLUS_SB(sb).free_blocks);
354                 return -ENOSPC;
355                 //BUG();
356         }
357
358         down(&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         up(&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                 u32 size = inode->i_size - 1;
447                 int res;
448
449                 page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
450                 if (!page)
451                         return;
452                 size &= PAGE_CACHE_SIZE - 1;
453                 size++;
454                 res = mapping->a_ops->prepare_write(NULL, page, size, size);
455                 if (!res)
456                         res = mapping->a_ops->commit_write(NULL, page, size, size);
457                 if (res)
458                         inode->i_size = HFSPLUS_I(inode).phys_size;
459                 unlock_page(page);
460                 page_cache_release(page);
461                 mark_inode_dirty(inode);
462                 return;
463         } else if (inode->i_size == HFSPLUS_I(inode).phys_size)
464                 return;
465
466         blk_cnt = (inode->i_size + HFSPLUS_SB(sb).alloc_blksz - 1) >> HFSPLUS_SB(sb).alloc_blksz_shift;
467         alloc_cnt = HFSPLUS_I(inode).alloc_blocks;
468         if (blk_cnt == alloc_cnt)
469                 goto out;
470
471         down(&HFSPLUS_I(inode).extents_lock);
472         hfs_find_init(HFSPLUS_SB(sb).ext_tree, &fd);
473         while (1) {
474                 if (alloc_cnt == HFSPLUS_I(inode).first_blocks) {
475                         hfsplus_free_extents(sb, HFSPLUS_I(inode).first_extents,
476                                              alloc_cnt, alloc_cnt - blk_cnt);
477                         hfsplus_dump_extent(HFSPLUS_I(inode).first_extents);
478                         HFSPLUS_I(inode).first_blocks = blk_cnt;
479                         break;
480                 }
481                 res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
482                 if (res)
483                         break;
484                 start = HFSPLUS_I(inode).cached_start;
485                 hfsplus_free_extents(sb, HFSPLUS_I(inode).cached_extents,
486                                      alloc_cnt - start, alloc_cnt - blk_cnt);
487                 hfsplus_dump_extent(HFSPLUS_I(inode).cached_extents);
488                 if (blk_cnt > start) {
489                         HFSPLUS_I(inode).flags |= HFSPLUS_FLG_EXT_DIRTY;
490                         break;
491                 }
492                 alloc_cnt = start;
493                 HFSPLUS_I(inode).cached_start = HFSPLUS_I(inode).cached_blocks = 0;
494                 HFSPLUS_I(inode).flags &= ~(HFSPLUS_FLG_EXT_DIRTY | HFSPLUS_FLG_EXT_NEW);
495                 hfs_brec_remove(&fd);
496         }
497         hfs_find_exit(&fd);
498         up(&HFSPLUS_I(inode).extents_lock);
499
500         HFSPLUS_I(inode).alloc_blocks = blk_cnt;
501 out:
502         HFSPLUS_I(inode).phys_size = inode->i_size;
503         HFSPLUS_I(inode).fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
504         inode_set_bytes(inode, HFSPLUS_I(inode).fs_blocks << sb->s_blocksize_bits);
505         mark_inode_dirty(inode);
506 }