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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2004, OGAWA Hirofumi | |
3 | * Released under GPL v2. | |
4 | */ | |
5 | ||
8c540a96 | 6 | #include <linux/blkdev.h> |
9e975dae | 7 | #include "fat.h" |
1da177e4 LT |
8 | |
9 | struct fatent_operations { | |
10 | void (*ent_blocknr)(struct super_block *, int, int *, sector_t *); | |
11 | void (*ent_set_ptr)(struct fat_entry *, int); | |
12 | int (*ent_bread)(struct super_block *, struct fat_entry *, | |
13 | int, sector_t); | |
14 | int (*ent_get)(struct fat_entry *); | |
15 | void (*ent_put)(struct fat_entry *, int); | |
16 | int (*ent_next)(struct fat_entry *); | |
17 | }; | |
18 | ||
98283bb4 OH |
19 | static DEFINE_SPINLOCK(fat12_entry_lock); |
20 | ||
1da177e4 LT |
21 | static void fat12_ent_blocknr(struct super_block *sb, int entry, |
22 | int *offset, sector_t *blocknr) | |
23 | { | |
24 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
25 | int bytes = entry + (entry >> 1); | |
ceee0d18 | 26 | WARN_ON(!fat_valid_entry(sbi, entry)); |
1da177e4 LT |
27 | *offset = bytes & (sb->s_blocksize - 1); |
28 | *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); | |
29 | } | |
30 | ||
31 | static void fat_ent_blocknr(struct super_block *sb, int entry, | |
32 | int *offset, sector_t *blocknr) | |
33 | { | |
34 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
35 | int bytes = (entry << sbi->fatent_shift); | |
ceee0d18 | 36 | WARN_ON(!fat_valid_entry(sbi, entry)); |
1da177e4 LT |
37 | *offset = bytes & (sb->s_blocksize - 1); |
38 | *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); | |
39 | } | |
40 | ||
41 | static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset) | |
42 | { | |
43 | struct buffer_head **bhs = fatent->bhs; | |
44 | if (fatent->nr_bhs == 1) { | |
45 | WARN_ON(offset >= (bhs[0]->b_size - 1)); | |
46 | fatent->u.ent12_p[0] = bhs[0]->b_data + offset; | |
47 | fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1); | |
48 | } else { | |
49 | WARN_ON(offset != (bhs[0]->b_size - 1)); | |
50 | fatent->u.ent12_p[0] = bhs[0]->b_data + offset; | |
51 | fatent->u.ent12_p[1] = bhs[1]->b_data; | |
52 | } | |
53 | } | |
54 | ||
55 | static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset) | |
56 | { | |
57 | WARN_ON(offset & (2 - 1)); | |
58 | fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset); | |
59 | } | |
60 | ||
61 | static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset) | |
62 | { | |
63 | WARN_ON(offset & (4 - 1)); | |
64 | fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset); | |
65 | } | |
66 | ||
67 | static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent, | |
68 | int offset, sector_t blocknr) | |
69 | { | |
70 | struct buffer_head **bhs = fatent->bhs; | |
71 | ||
72 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
b522412a AV |
73 | fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
74 | ||
1da177e4 LT |
75 | bhs[0] = sb_bread(sb, blocknr); |
76 | if (!bhs[0]) | |
77 | goto err; | |
78 | ||
79 | if ((offset + 1) < sb->s_blocksize) | |
80 | fatent->nr_bhs = 1; | |
81 | else { | |
82 | /* This entry is block boundary, it needs the next block */ | |
83 | blocknr++; | |
84 | bhs[1] = sb_bread(sb, blocknr); | |
85 | if (!bhs[1]) | |
86 | goto err_brelse; | |
87 | fatent->nr_bhs = 2; | |
88 | } | |
89 | fat12_ent_set_ptr(fatent, offset); | |
90 | return 0; | |
91 | ||
92 | err_brelse: | |
93 | brelse(bhs[0]); | |
94 | err: | |
869f58c0 | 95 | fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)", (llu)blocknr); |
1da177e4 LT |
96 | return -EIO; |
97 | } | |
98 | ||
99 | static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent, | |
100 | int offset, sector_t blocknr) | |
101 | { | |
8992de4c | 102 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
1da177e4 LT |
103 | |
104 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
b522412a | 105 | fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
1da177e4 LT |
106 | fatent->bhs[0] = sb_bread(sb, blocknr); |
107 | if (!fatent->bhs[0]) { | |
869f58c0 | 108 | fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)", |
c3302931 | 109 | (llu)blocknr); |
1da177e4 LT |
110 | return -EIO; |
111 | } | |
112 | fatent->nr_bhs = 1; | |
113 | ops->ent_set_ptr(fatent, offset); | |
114 | return 0; | |
115 | } | |
116 | ||
117 | static int fat12_ent_get(struct fat_entry *fatent) | |
118 | { | |
119 | u8 **ent12_p = fatent->u.ent12_p; | |
120 | int next; | |
121 | ||
98283bb4 | 122 | spin_lock(&fat12_entry_lock); |
1da177e4 LT |
123 | if (fatent->entry & 1) |
124 | next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4); | |
125 | else | |
126 | next = (*ent12_p[1] << 8) | *ent12_p[0]; | |
98283bb4 OH |
127 | spin_unlock(&fat12_entry_lock); |
128 | ||
1da177e4 LT |
129 | next &= 0x0fff; |
130 | if (next >= BAD_FAT12) | |
131 | next = FAT_ENT_EOF; | |
132 | return next; | |
133 | } | |
134 | ||
135 | static int fat16_ent_get(struct fat_entry *fatent) | |
136 | { | |
137 | int next = le16_to_cpu(*fatent->u.ent16_p); | |
138 | WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1)); | |
139 | if (next >= BAD_FAT16) | |
140 | next = FAT_ENT_EOF; | |
141 | return next; | |
142 | } | |
143 | ||
144 | static int fat32_ent_get(struct fat_entry *fatent) | |
145 | { | |
146 | int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff; | |
147 | WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1)); | |
148 | if (next >= BAD_FAT32) | |
149 | next = FAT_ENT_EOF; | |
150 | return next; | |
151 | } | |
152 | ||
153 | static void fat12_ent_put(struct fat_entry *fatent, int new) | |
154 | { | |
155 | u8 **ent12_p = fatent->u.ent12_p; | |
156 | ||
157 | if (new == FAT_ENT_EOF) | |
158 | new = EOF_FAT12; | |
159 | ||
98283bb4 | 160 | spin_lock(&fat12_entry_lock); |
1da177e4 LT |
161 | if (fatent->entry & 1) { |
162 | *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f); | |
163 | *ent12_p[1] = new >> 4; | |
164 | } else { | |
165 | *ent12_p[0] = new & 0xff; | |
166 | *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8); | |
167 | } | |
98283bb4 | 168 | spin_unlock(&fat12_entry_lock); |
1da177e4 | 169 | |
b522412a | 170 | mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
1da177e4 | 171 | if (fatent->nr_bhs == 2) |
b522412a | 172 | mark_buffer_dirty_inode(fatent->bhs[1], fatent->fat_inode); |
1da177e4 LT |
173 | } |
174 | ||
175 | static void fat16_ent_put(struct fat_entry *fatent, int new) | |
176 | { | |
177 | if (new == FAT_ENT_EOF) | |
178 | new = EOF_FAT16; | |
179 | ||
180 | *fatent->u.ent16_p = cpu_to_le16(new); | |
b522412a | 181 | mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
1da177e4 LT |
182 | } |
183 | ||
184 | static void fat32_ent_put(struct fat_entry *fatent, int new) | |
185 | { | |
1da177e4 LT |
186 | WARN_ON(new & 0xf0000000); |
187 | new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; | |
188 | *fatent->u.ent32_p = cpu_to_le32(new); | |
b522412a | 189 | mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
1da177e4 LT |
190 | } |
191 | ||
192 | static int fat12_ent_next(struct fat_entry *fatent) | |
193 | { | |
194 | u8 **ent12_p = fatent->u.ent12_p; | |
195 | struct buffer_head **bhs = fatent->bhs; | |
196 | u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1); | |
197 | ||
198 | fatent->entry++; | |
199 | if (fatent->nr_bhs == 1) { | |
441dff34 CJB |
200 | WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + |
201 | (bhs[0]->b_size - 2))); | |
202 | WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + | |
203 | (bhs[0]->b_size - 1))); | |
1da177e4 LT |
204 | if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) { |
205 | ent12_p[0] = nextp - 1; | |
206 | ent12_p[1] = nextp; | |
207 | return 1; | |
208 | } | |
209 | } else { | |
441dff34 CJB |
210 | WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + |
211 | (bhs[0]->b_size - 1))); | |
1da177e4 LT |
212 | WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data); |
213 | ent12_p[0] = nextp - 1; | |
214 | ent12_p[1] = nextp; | |
215 | brelse(bhs[0]); | |
216 | bhs[0] = bhs[1]; | |
217 | fatent->nr_bhs = 1; | |
218 | return 1; | |
219 | } | |
220 | ent12_p[0] = NULL; | |
221 | ent12_p[1] = NULL; | |
222 | return 0; | |
223 | } | |
224 | ||
225 | static int fat16_ent_next(struct fat_entry *fatent) | |
226 | { | |
227 | const struct buffer_head *bh = fatent->bhs[0]; | |
228 | fatent->entry++; | |
229 | if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) { | |
230 | fatent->u.ent16_p++; | |
231 | return 1; | |
232 | } | |
233 | fatent->u.ent16_p = NULL; | |
234 | return 0; | |
235 | } | |
236 | ||
237 | static int fat32_ent_next(struct fat_entry *fatent) | |
238 | { | |
239 | const struct buffer_head *bh = fatent->bhs[0]; | |
240 | fatent->entry++; | |
241 | if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) { | |
242 | fatent->u.ent32_p++; | |
243 | return 1; | |
244 | } | |
245 | fatent->u.ent32_p = NULL; | |
246 | return 0; | |
247 | } | |
248 | ||
8992de4c | 249 | static const struct fatent_operations fat12_ops = { |
1da177e4 LT |
250 | .ent_blocknr = fat12_ent_blocknr, |
251 | .ent_set_ptr = fat12_ent_set_ptr, | |
252 | .ent_bread = fat12_ent_bread, | |
253 | .ent_get = fat12_ent_get, | |
254 | .ent_put = fat12_ent_put, | |
255 | .ent_next = fat12_ent_next, | |
256 | }; | |
257 | ||
8992de4c | 258 | static const struct fatent_operations fat16_ops = { |
1da177e4 LT |
259 | .ent_blocknr = fat_ent_blocknr, |
260 | .ent_set_ptr = fat16_ent_set_ptr, | |
261 | .ent_bread = fat_ent_bread, | |
262 | .ent_get = fat16_ent_get, | |
263 | .ent_put = fat16_ent_put, | |
264 | .ent_next = fat16_ent_next, | |
265 | }; | |
266 | ||
8992de4c | 267 | static const struct fatent_operations fat32_ops = { |
1da177e4 LT |
268 | .ent_blocknr = fat_ent_blocknr, |
269 | .ent_set_ptr = fat32_ent_set_ptr, | |
270 | .ent_bread = fat_ent_bread, | |
271 | .ent_get = fat32_ent_get, | |
272 | .ent_put = fat32_ent_put, | |
273 | .ent_next = fat32_ent_next, | |
274 | }; | |
275 | ||
276 | static inline void lock_fat(struct msdos_sb_info *sbi) | |
277 | { | |
6b9438e1 | 278 | mutex_lock(&sbi->fat_lock); |
1da177e4 LT |
279 | } |
280 | ||
281 | static inline void unlock_fat(struct msdos_sb_info *sbi) | |
282 | { | |
6b9438e1 | 283 | mutex_unlock(&sbi->fat_lock); |
1da177e4 LT |
284 | } |
285 | ||
286 | void fat_ent_access_init(struct super_block *sb) | |
287 | { | |
288 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
289 | ||
6b9438e1 | 290 | mutex_init(&sbi->fat_lock); |
1da177e4 LT |
291 | |
292 | switch (sbi->fat_bits) { | |
293 | case 32: | |
294 | sbi->fatent_shift = 2; | |
295 | sbi->fatent_ops = &fat32_ops; | |
296 | break; | |
297 | case 16: | |
298 | sbi->fatent_shift = 1; | |
299 | sbi->fatent_ops = &fat16_ops; | |
300 | break; | |
301 | case 12: | |
302 | sbi->fatent_shift = -1; | |
303 | sbi->fatent_ops = &fat12_ops; | |
304 | break; | |
305 | } | |
306 | } | |
307 | ||
90b43665 AB |
308 | static void mark_fsinfo_dirty(struct super_block *sb) |
309 | { | |
78491189 AB |
310 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
311 | ||
bc98a42c | 312 | if (sb_rdonly(sb) || sbi->fat_bits != 32) |
78491189 AB |
313 | return; |
314 | ||
315 | __mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC); | |
90b43665 AB |
316 | } |
317 | ||
1da177e4 LT |
318 | static inline int fat_ent_update_ptr(struct super_block *sb, |
319 | struct fat_entry *fatent, | |
320 | int offset, sector_t blocknr) | |
321 | { | |
322 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 323 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
324 | struct buffer_head **bhs = fatent->bhs; |
325 | ||
326 | /* Is this fatent's blocks including this entry? */ | |
327 | if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr) | |
328 | return 0; | |
5e35dd46 OH |
329 | if (sbi->fat_bits == 12) { |
330 | if ((offset + 1) < sb->s_blocksize) { | |
331 | /* This entry is on bhs[0]. */ | |
332 | if (fatent->nr_bhs == 2) { | |
333 | brelse(bhs[1]); | |
334 | fatent->nr_bhs = 1; | |
335 | } | |
336 | } else { | |
337 | /* This entry needs the next block. */ | |
338 | if (fatent->nr_bhs != 2) | |
339 | return 0; | |
340 | if (bhs[1]->b_blocknr != (blocknr + 1)) | |
341 | return 0; | |
342 | } | |
1da177e4 LT |
343 | } |
344 | ops->ent_set_ptr(fatent, offset); | |
345 | return 1; | |
346 | } | |
347 | ||
348 | int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry) | |
349 | { | |
350 | struct super_block *sb = inode->i_sb; | |
351 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); | |
8992de4c | 352 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
353 | int err, offset; |
354 | sector_t blocknr; | |
355 | ||
ceee0d18 | 356 | if (!fat_valid_entry(sbi, entry)) { |
1da177e4 | 357 | fatent_brelse(fatent); |
85c78591 | 358 | fat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", entry); |
1da177e4 LT |
359 | return -EIO; |
360 | } | |
361 | ||
362 | fatent_set_entry(fatent, entry); | |
363 | ops->ent_blocknr(sb, entry, &offset, &blocknr); | |
364 | ||
365 | if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) { | |
366 | fatent_brelse(fatent); | |
367 | err = ops->ent_bread(sb, fatent, offset, blocknr); | |
368 | if (err) | |
369 | return err; | |
370 | } | |
371 | return ops->ent_get(fatent); | |
372 | } | |
373 | ||
374 | /* FIXME: We can write the blocks as more big chunk. */ | |
375 | static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, | |
376 | int nr_bhs) | |
377 | { | |
378 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
379 | struct buffer_head *c_bh; | |
380 | int err, n, copy; | |
381 | ||
382 | err = 0; | |
383 | for (copy = 1; copy < sbi->fats; copy++) { | |
384 | sector_t backup_fat = sbi->fat_length * copy; | |
385 | ||
386 | for (n = 0; n < nr_bhs; n++) { | |
387 | c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr); | |
388 | if (!c_bh) { | |
389 | err = -ENOMEM; | |
390 | goto error; | |
391 | } | |
64abc7fb OH |
392 | /* Avoid race with userspace read via bdev */ |
393 | lock_buffer(c_bh); | |
1da177e4 LT |
394 | memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); |
395 | set_buffer_uptodate(c_bh); | |
64abc7fb | 396 | unlock_buffer(c_bh); |
b522412a | 397 | mark_buffer_dirty_inode(c_bh, sbi->fat_inode); |
1751e8a6 | 398 | if (sb->s_flags & SB_SYNCHRONOUS) |
1da177e4 LT |
399 | err = sync_dirty_buffer(c_bh); |
400 | brelse(c_bh); | |
401 | if (err) | |
402 | goto error; | |
403 | } | |
404 | } | |
405 | error: | |
406 | return err; | |
407 | } | |
408 | ||
409 | int fat_ent_write(struct inode *inode, struct fat_entry *fatent, | |
410 | int new, int wait) | |
411 | { | |
412 | struct super_block *sb = inode->i_sb; | |
8992de4c | 413 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
1da177e4 LT |
414 | int err; |
415 | ||
416 | ops->ent_put(fatent, new); | |
417 | if (wait) { | |
418 | err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs); | |
419 | if (err) | |
420 | return err; | |
421 | } | |
422 | return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs); | |
423 | } | |
424 | ||
425 | static inline int fat_ent_next(struct msdos_sb_info *sbi, | |
426 | struct fat_entry *fatent) | |
427 | { | |
428 | if (sbi->fatent_ops->ent_next(fatent)) { | |
429 | if (fatent->entry < sbi->max_cluster) | |
430 | return 1; | |
431 | } | |
432 | return 0; | |
433 | } | |
434 | ||
435 | static inline int fat_ent_read_block(struct super_block *sb, | |
436 | struct fat_entry *fatent) | |
437 | { | |
8992de4c | 438 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
1da177e4 LT |
439 | sector_t blocknr; |
440 | int offset; | |
441 | ||
442 | fatent_brelse(fatent); | |
443 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
444 | return ops->ent_bread(sb, fatent, offset, blocknr); | |
445 | } | |
446 | ||
447 | static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs, | |
448 | struct fat_entry *fatent) | |
449 | { | |
450 | int n, i; | |
451 | ||
452 | for (n = 0; n < fatent->nr_bhs; n++) { | |
453 | for (i = 0; i < *nr_bhs; i++) { | |
454 | if (fatent->bhs[n] == bhs[i]) | |
455 | break; | |
456 | } | |
457 | if (i == *nr_bhs) { | |
458 | get_bh(fatent->bhs[n]); | |
459 | bhs[i] = fatent->bhs[n]; | |
460 | (*nr_bhs)++; | |
461 | } | |
462 | } | |
463 | } | |
464 | ||
465 | int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster) | |
466 | { | |
467 | struct super_block *sb = inode->i_sb; | |
468 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 469 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
470 | struct fat_entry fatent, prev_ent; |
471 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
472 | int i, count, err, nr_bhs, idx_clus; | |
473 | ||
474 | BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */ | |
475 | ||
476 | lock_fat(sbi); | |
606e423e OH |
477 | if (sbi->free_clusters != -1 && sbi->free_clus_valid && |
478 | sbi->free_clusters < nr_cluster) { | |
1da177e4 LT |
479 | unlock_fat(sbi); |
480 | return -ENOSPC; | |
481 | } | |
482 | ||
483 | err = nr_bhs = idx_clus = 0; | |
484 | count = FAT_START_ENT; | |
485 | fatent_init(&prev_ent); | |
486 | fatent_init(&fatent); | |
487 | fatent_set_entry(&fatent, sbi->prev_free + 1); | |
488 | while (count < sbi->max_cluster) { | |
489 | if (fatent.entry >= sbi->max_cluster) | |
490 | fatent.entry = FAT_START_ENT; | |
491 | fatent_set_entry(&fatent, fatent.entry); | |
492 | err = fat_ent_read_block(sb, &fatent); | |
493 | if (err) | |
494 | goto out; | |
495 | ||
496 | /* Find the free entries in a block */ | |
497 | do { | |
498 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) { | |
499 | int entry = fatent.entry; | |
500 | ||
501 | /* make the cluster chain */ | |
502 | ops->ent_put(&fatent, FAT_ENT_EOF); | |
503 | if (prev_ent.nr_bhs) | |
504 | ops->ent_put(&prev_ent, entry); | |
505 | ||
506 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
507 | ||
508 | sbi->prev_free = entry; | |
509 | if (sbi->free_clusters != -1) | |
510 | sbi->free_clusters--; | |
511 | ||
512 | cluster[idx_clus] = entry; | |
513 | idx_clus++; | |
514 | if (idx_clus == nr_cluster) | |
515 | goto out; | |
516 | ||
517 | /* | |
518 | * fat_collect_bhs() gets ref-count of bhs, | |
519 | * so we can still use the prev_ent. | |
520 | */ | |
521 | prev_ent = fatent; | |
522 | } | |
523 | count++; | |
524 | if (count == sbi->max_cluster) | |
525 | break; | |
526 | } while (fat_ent_next(sbi, &fatent)); | |
527 | } | |
528 | ||
529 | /* Couldn't allocate the free entries */ | |
530 | sbi->free_clusters = 0; | |
606e423e | 531 | sbi->free_clus_valid = 1; |
1da177e4 LT |
532 | err = -ENOSPC; |
533 | ||
534 | out: | |
535 | unlock_fat(sbi); | |
330fe3c4 | 536 | mark_fsinfo_dirty(sb); |
1da177e4 LT |
537 | fatent_brelse(&fatent); |
538 | if (!err) { | |
539 | if (inode_needs_sync(inode)) | |
540 | err = fat_sync_bhs(bhs, nr_bhs); | |
541 | if (!err) | |
542 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
543 | } | |
544 | for (i = 0; i < nr_bhs; i++) | |
545 | brelse(bhs[i]); | |
1da177e4 LT |
546 | |
547 | if (err && idx_clus) | |
548 | fat_free_clusters(inode, cluster[0]); | |
549 | ||
550 | return err; | |
551 | } | |
552 | ||
553 | int fat_free_clusters(struct inode *inode, int cluster) | |
554 | { | |
555 | struct super_block *sb = inode->i_sb; | |
556 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 557 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
558 | struct fat_entry fatent; |
559 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
560 | int i, err, nr_bhs; | |
330fe3c4 | 561 | int first_cl = cluster, dirty_fsinfo = 0; |
1da177e4 LT |
562 | |
563 | nr_bhs = 0; | |
564 | fatent_init(&fatent); | |
565 | lock_fat(sbi); | |
566 | do { | |
567 | cluster = fat_ent_read(inode, &fatent, cluster); | |
568 | if (cluster < 0) { | |
569 | err = cluster; | |
570 | goto error; | |
571 | } else if (cluster == FAT_ENT_FREE) { | |
85c78591 | 572 | fat_fs_error(sb, "%s: deleting FAT entry beyond EOF", |
8e24eea7 | 573 | __func__); |
1da177e4 LT |
574 | err = -EIO; |
575 | goto error; | |
576 | } | |
577 | ||
681142f9 CH |
578 | if (sbi->options.discard) { |
579 | /* | |
580 | * Issue discard for the sectors we no longer | |
581 | * care about, batching contiguous clusters | |
582 | * into one request | |
583 | */ | |
584 | if (cluster != fatent.entry + 1) { | |
585 | int nr_clus = fatent.entry - first_cl + 1; | |
586 | ||
587 | sb_issue_discard(sb, | |
588 | fat_clus_to_blknr(sbi, first_cl), | |
2cf6d26a | 589 | nr_clus * sbi->sec_per_clus, |
dd3932ed | 590 | GFP_NOFS, 0); |
681142f9 CH |
591 | |
592 | first_cl = cluster; | |
593 | } | |
8c540a96 DW |
594 | } |
595 | ||
1da177e4 | 596 | ops->ent_put(&fatent, FAT_ENT_FREE); |
a6bf6b21 | 597 | if (sbi->free_clusters != -1) { |
1da177e4 | 598 | sbi->free_clusters++; |
330fe3c4 | 599 | dirty_fsinfo = 1; |
a6bf6b21 | 600 | } |
1da177e4 LT |
601 | |
602 | if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) { | |
1751e8a6 | 603 | if (sb->s_flags & SB_SYNCHRONOUS) { |
1da177e4 LT |
604 | err = fat_sync_bhs(bhs, nr_bhs); |
605 | if (err) | |
606 | goto error; | |
607 | } | |
608 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
609 | if (err) | |
610 | goto error; | |
611 | for (i = 0; i < nr_bhs; i++) | |
612 | brelse(bhs[i]); | |
613 | nr_bhs = 0; | |
614 | } | |
615 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
616 | } while (cluster != FAT_ENT_EOF); | |
617 | ||
1751e8a6 | 618 | if (sb->s_flags & SB_SYNCHRONOUS) { |
1da177e4 LT |
619 | err = fat_sync_bhs(bhs, nr_bhs); |
620 | if (err) | |
621 | goto error; | |
622 | } | |
623 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
624 | error: | |
625 | fatent_brelse(&fatent); | |
626 | for (i = 0; i < nr_bhs; i++) | |
627 | brelse(bhs[i]); | |
628 | unlock_fat(sbi); | |
330fe3c4 AB |
629 | if (dirty_fsinfo) |
630 | mark_fsinfo_dirty(sb); | |
1da177e4 | 631 | |
1da177e4 LT |
632 | return err; |
633 | } | |
7c709d00 | 634 | EXPORT_SYMBOL_GPL(fat_free_clusters); |
1da177e4 | 635 | |
9f966be8 OH |
636 | /* 128kb is the whole sectors for FAT12 and FAT16 */ |
637 | #define FAT_READA_SIZE (128 * 1024) | |
638 | ||
639 | static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent, | |
640 | unsigned long reada_blocks) | |
641 | { | |
8992de4c | 642 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
9f966be8 OH |
643 | sector_t blocknr; |
644 | int i, offset; | |
645 | ||
646 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
647 | ||
648 | for (i = 0; i < reada_blocks; i++) | |
649 | sb_breadahead(sb, blocknr + i); | |
650 | } | |
651 | ||
1da177e4 LT |
652 | int fat_count_free_clusters(struct super_block *sb) |
653 | { | |
654 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 655 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 | 656 | struct fat_entry fatent; |
9f966be8 | 657 | unsigned long reada_blocks, reada_mask, cur_block; |
1da177e4 LT |
658 | int err = 0, free; |
659 | ||
660 | lock_fat(sbi); | |
606e423e | 661 | if (sbi->free_clusters != -1 && sbi->free_clus_valid) |
1da177e4 LT |
662 | goto out; |
663 | ||
9f966be8 OH |
664 | reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits; |
665 | reada_mask = reada_blocks - 1; | |
666 | cur_block = 0; | |
667 | ||
1da177e4 LT |
668 | free = 0; |
669 | fatent_init(&fatent); | |
670 | fatent_set_entry(&fatent, FAT_START_ENT); | |
671 | while (fatent.entry < sbi->max_cluster) { | |
9f966be8 OH |
672 | /* readahead of fat blocks */ |
673 | if ((cur_block & reada_mask) == 0) { | |
674 | unsigned long rest = sbi->fat_length - cur_block; | |
675 | fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); | |
676 | } | |
677 | cur_block++; | |
678 | ||
1da177e4 LT |
679 | err = fat_ent_read_block(sb, &fatent); |
680 | if (err) | |
681 | goto out; | |
682 | ||
683 | do { | |
684 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) | |
685 | free++; | |
686 | } while (fat_ent_next(sbi, &fatent)); | |
fd7c669f | 687 | cond_resched(); |
1da177e4 LT |
688 | } |
689 | sbi->free_clusters = free; | |
606e423e | 690 | sbi->free_clus_valid = 1; |
90b43665 | 691 | mark_fsinfo_dirty(sb); |
1da177e4 LT |
692 | fatent_brelse(&fatent); |
693 | out: | |
694 | unlock_fat(sbi); | |
695 | return err; | |
696 | } |