Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2004, OGAWA Hirofumi | |
3 | * Released under GPL v2. | |
4 | */ | |
5 | ||
6 | #include <linux/module.h> | |
7 | #include <linux/fs.h> | |
8 | #include <linux/msdos_fs.h> | |
9 | ||
10 | struct fatent_operations { | |
11 | void (*ent_blocknr)(struct super_block *, int, int *, sector_t *); | |
12 | void (*ent_set_ptr)(struct fat_entry *, int); | |
13 | int (*ent_bread)(struct super_block *, struct fat_entry *, | |
14 | int, sector_t); | |
15 | int (*ent_get)(struct fat_entry *); | |
16 | void (*ent_put)(struct fat_entry *, int); | |
17 | int (*ent_next)(struct fat_entry *); | |
18 | }; | |
19 | ||
98283bb4 OH |
20 | static DEFINE_SPINLOCK(fat12_entry_lock); |
21 | ||
1da177e4 LT |
22 | static void fat12_ent_blocknr(struct super_block *sb, int entry, |
23 | int *offset, sector_t *blocknr) | |
24 | { | |
25 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
26 | int bytes = entry + (entry >> 1); | |
27 | WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry); | |
28 | *offset = bytes & (sb->s_blocksize - 1); | |
29 | *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); | |
30 | } | |
31 | ||
32 | static void fat_ent_blocknr(struct super_block *sb, int entry, | |
33 | int *offset, sector_t *blocknr) | |
34 | { | |
35 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
36 | int bytes = (entry << sbi->fatent_shift); | |
37 | WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry); | |
38 | *offset = bytes & (sb->s_blocksize - 1); | |
39 | *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); | |
40 | } | |
41 | ||
42 | static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset) | |
43 | { | |
44 | struct buffer_head **bhs = fatent->bhs; | |
45 | if (fatent->nr_bhs == 1) { | |
46 | WARN_ON(offset >= (bhs[0]->b_size - 1)); | |
47 | fatent->u.ent12_p[0] = bhs[0]->b_data + offset; | |
48 | fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1); | |
49 | } else { | |
50 | WARN_ON(offset != (bhs[0]->b_size - 1)); | |
51 | fatent->u.ent12_p[0] = bhs[0]->b_data + offset; | |
52 | fatent->u.ent12_p[1] = bhs[1]->b_data; | |
53 | } | |
54 | } | |
55 | ||
56 | static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset) | |
57 | { | |
58 | WARN_ON(offset & (2 - 1)); | |
59 | fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset); | |
60 | } | |
61 | ||
62 | static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset) | |
63 | { | |
64 | WARN_ON(offset & (4 - 1)); | |
65 | fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset); | |
66 | } | |
67 | ||
68 | static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent, | |
69 | int offset, sector_t blocknr) | |
70 | { | |
71 | struct buffer_head **bhs = fatent->bhs; | |
72 | ||
73 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
74 | bhs[0] = sb_bread(sb, blocknr); | |
75 | if (!bhs[0]) | |
76 | goto err; | |
77 | ||
78 | if ((offset + 1) < sb->s_blocksize) | |
79 | fatent->nr_bhs = 1; | |
80 | else { | |
81 | /* This entry is block boundary, it needs the next block */ | |
82 | blocknr++; | |
83 | bhs[1] = sb_bread(sb, blocknr); | |
84 | if (!bhs[1]) | |
85 | goto err_brelse; | |
86 | fatent->nr_bhs = 2; | |
87 | } | |
88 | fat12_ent_set_ptr(fatent, offset); | |
89 | return 0; | |
90 | ||
91 | err_brelse: | |
92 | brelse(bhs[0]); | |
93 | err: | |
94 | printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n", | |
95 | (unsigned long long)blocknr); | |
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 | { | |
102 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
103 | ||
104 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
105 | fatent->bhs[0] = sb_bread(sb, blocknr); | |
106 | if (!fatent->bhs[0]) { | |
107 | printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n", | |
108 | (unsigned long long)blocknr); | |
109 | return -EIO; | |
110 | } | |
111 | fatent->nr_bhs = 1; | |
112 | ops->ent_set_ptr(fatent, offset); | |
113 | return 0; | |
114 | } | |
115 | ||
116 | static int fat12_ent_get(struct fat_entry *fatent) | |
117 | { | |
118 | u8 **ent12_p = fatent->u.ent12_p; | |
119 | int next; | |
120 | ||
98283bb4 | 121 | spin_lock(&fat12_entry_lock); |
1da177e4 LT |
122 | if (fatent->entry & 1) |
123 | next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4); | |
124 | else | |
125 | next = (*ent12_p[1] << 8) | *ent12_p[0]; | |
98283bb4 OH |
126 | spin_unlock(&fat12_entry_lock); |
127 | ||
1da177e4 LT |
128 | next &= 0x0fff; |
129 | if (next >= BAD_FAT12) | |
130 | next = FAT_ENT_EOF; | |
131 | return next; | |
132 | } | |
133 | ||
134 | static int fat16_ent_get(struct fat_entry *fatent) | |
135 | { | |
136 | int next = le16_to_cpu(*fatent->u.ent16_p); | |
137 | WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1)); | |
138 | if (next >= BAD_FAT16) | |
139 | next = FAT_ENT_EOF; | |
140 | return next; | |
141 | } | |
142 | ||
143 | static int fat32_ent_get(struct fat_entry *fatent) | |
144 | { | |
145 | int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff; | |
146 | WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1)); | |
147 | if (next >= BAD_FAT32) | |
148 | next = FAT_ENT_EOF; | |
149 | return next; | |
150 | } | |
151 | ||
152 | static void fat12_ent_put(struct fat_entry *fatent, int new) | |
153 | { | |
154 | u8 **ent12_p = fatent->u.ent12_p; | |
155 | ||
156 | if (new == FAT_ENT_EOF) | |
157 | new = EOF_FAT12; | |
158 | ||
98283bb4 | 159 | spin_lock(&fat12_entry_lock); |
1da177e4 LT |
160 | if (fatent->entry & 1) { |
161 | *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f); | |
162 | *ent12_p[1] = new >> 4; | |
163 | } else { | |
164 | *ent12_p[0] = new & 0xff; | |
165 | *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8); | |
166 | } | |
98283bb4 | 167 | spin_unlock(&fat12_entry_lock); |
1da177e4 LT |
168 | |
169 | mark_buffer_dirty(fatent->bhs[0]); | |
170 | if (fatent->nr_bhs == 2) | |
171 | mark_buffer_dirty(fatent->bhs[1]); | |
172 | } | |
173 | ||
174 | static void fat16_ent_put(struct fat_entry *fatent, int new) | |
175 | { | |
176 | if (new == FAT_ENT_EOF) | |
177 | new = EOF_FAT16; | |
178 | ||
179 | *fatent->u.ent16_p = cpu_to_le16(new); | |
180 | mark_buffer_dirty(fatent->bhs[0]); | |
181 | } | |
182 | ||
183 | static void fat32_ent_put(struct fat_entry *fatent, int new) | |
184 | { | |
185 | if (new == FAT_ENT_EOF) | |
186 | new = EOF_FAT32; | |
187 | ||
188 | WARN_ON(new & 0xf0000000); | |
189 | new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; | |
190 | *fatent->u.ent32_p = cpu_to_le32(new); | |
191 | mark_buffer_dirty(fatent->bhs[0]); | |
192 | } | |
193 | ||
194 | static int fat12_ent_next(struct fat_entry *fatent) | |
195 | { | |
196 | u8 **ent12_p = fatent->u.ent12_p; | |
197 | struct buffer_head **bhs = fatent->bhs; | |
198 | u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1); | |
199 | ||
200 | fatent->entry++; | |
201 | if (fatent->nr_bhs == 1) { | |
202 | WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 2))); | |
203 | WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))); | |
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 { | |
210 | WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))); | |
211 | WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data); | |
212 | ent12_p[0] = nextp - 1; | |
213 | ent12_p[1] = nextp; | |
214 | brelse(bhs[0]); | |
215 | bhs[0] = bhs[1]; | |
216 | fatent->nr_bhs = 1; | |
217 | return 1; | |
218 | } | |
219 | ent12_p[0] = NULL; | |
220 | ent12_p[1] = NULL; | |
221 | return 0; | |
222 | } | |
223 | ||
224 | static int fat16_ent_next(struct fat_entry *fatent) | |
225 | { | |
226 | const struct buffer_head *bh = fatent->bhs[0]; | |
227 | fatent->entry++; | |
228 | if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) { | |
229 | fatent->u.ent16_p++; | |
230 | return 1; | |
231 | } | |
232 | fatent->u.ent16_p = NULL; | |
233 | return 0; | |
234 | } | |
235 | ||
236 | static int fat32_ent_next(struct fat_entry *fatent) | |
237 | { | |
238 | const struct buffer_head *bh = fatent->bhs[0]; | |
239 | fatent->entry++; | |
240 | if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) { | |
241 | fatent->u.ent32_p++; | |
242 | return 1; | |
243 | } | |
244 | fatent->u.ent32_p = NULL; | |
245 | return 0; | |
246 | } | |
247 | ||
248 | static struct fatent_operations fat12_ops = { | |
249 | .ent_blocknr = fat12_ent_blocknr, | |
250 | .ent_set_ptr = fat12_ent_set_ptr, | |
251 | .ent_bread = fat12_ent_bread, | |
252 | .ent_get = fat12_ent_get, | |
253 | .ent_put = fat12_ent_put, | |
254 | .ent_next = fat12_ent_next, | |
255 | }; | |
256 | ||
257 | static struct fatent_operations fat16_ops = { | |
258 | .ent_blocknr = fat_ent_blocknr, | |
259 | .ent_set_ptr = fat16_ent_set_ptr, | |
260 | .ent_bread = fat_ent_bread, | |
261 | .ent_get = fat16_ent_get, | |
262 | .ent_put = fat16_ent_put, | |
263 | .ent_next = fat16_ent_next, | |
264 | }; | |
265 | ||
266 | static struct fatent_operations fat32_ops = { | |
267 | .ent_blocknr = fat_ent_blocknr, | |
268 | .ent_set_ptr = fat32_ent_set_ptr, | |
269 | .ent_bread = fat_ent_bread, | |
270 | .ent_get = fat32_ent_get, | |
271 | .ent_put = fat32_ent_put, | |
272 | .ent_next = fat32_ent_next, | |
273 | }; | |
274 | ||
275 | static inline void lock_fat(struct msdos_sb_info *sbi) | |
276 | { | |
6b9438e1 | 277 | mutex_lock(&sbi->fat_lock); |
1da177e4 LT |
278 | } |
279 | ||
280 | static inline void unlock_fat(struct msdos_sb_info *sbi) | |
281 | { | |
6b9438e1 | 282 | mutex_unlock(&sbi->fat_lock); |
1da177e4 LT |
283 | } |
284 | ||
285 | void fat_ent_access_init(struct super_block *sb) | |
286 | { | |
287 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
288 | ||
6b9438e1 | 289 | mutex_init(&sbi->fat_lock); |
1da177e4 LT |
290 | |
291 | switch (sbi->fat_bits) { | |
292 | case 32: | |
293 | sbi->fatent_shift = 2; | |
294 | sbi->fatent_ops = &fat32_ops; | |
295 | break; | |
296 | case 16: | |
297 | sbi->fatent_shift = 1; | |
298 | sbi->fatent_ops = &fat16_ops; | |
299 | break; | |
300 | case 12: | |
301 | sbi->fatent_shift = -1; | |
302 | sbi->fatent_ops = &fat12_ops; | |
303 | break; | |
304 | } | |
305 | } | |
306 | ||
307 | static inline int fat_ent_update_ptr(struct super_block *sb, | |
308 | struct fat_entry *fatent, | |
309 | int offset, sector_t blocknr) | |
310 | { | |
311 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
312 | struct fatent_operations *ops = sbi->fatent_ops; | |
313 | struct buffer_head **bhs = fatent->bhs; | |
314 | ||
315 | /* Is this fatent's blocks including this entry? */ | |
316 | if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr) | |
317 | return 0; | |
318 | /* Does this entry need the next block? */ | |
319 | if (sbi->fat_bits == 12 && (offset + 1) >= sb->s_blocksize) { | |
320 | if (fatent->nr_bhs != 2 || bhs[1]->b_blocknr != (blocknr + 1)) | |
321 | return 0; | |
322 | } | |
323 | ops->ent_set_ptr(fatent, offset); | |
324 | return 1; | |
325 | } | |
326 | ||
327 | int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry) | |
328 | { | |
329 | struct super_block *sb = inode->i_sb; | |
330 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); | |
331 | struct fatent_operations *ops = sbi->fatent_ops; | |
332 | int err, offset; | |
333 | sector_t blocknr; | |
334 | ||
335 | if (entry < FAT_START_ENT || sbi->max_cluster <= entry) { | |
336 | fatent_brelse(fatent); | |
337 | fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", entry); | |
338 | return -EIO; | |
339 | } | |
340 | ||
341 | fatent_set_entry(fatent, entry); | |
342 | ops->ent_blocknr(sb, entry, &offset, &blocknr); | |
343 | ||
344 | if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) { | |
345 | fatent_brelse(fatent); | |
346 | err = ops->ent_bread(sb, fatent, offset, blocknr); | |
347 | if (err) | |
348 | return err; | |
349 | } | |
350 | return ops->ent_get(fatent); | |
351 | } | |
352 | ||
353 | /* FIXME: We can write the blocks as more big chunk. */ | |
354 | static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, | |
355 | int nr_bhs) | |
356 | { | |
357 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
358 | struct buffer_head *c_bh; | |
359 | int err, n, copy; | |
360 | ||
361 | err = 0; | |
362 | for (copy = 1; copy < sbi->fats; copy++) { | |
363 | sector_t backup_fat = sbi->fat_length * copy; | |
364 | ||
365 | for (n = 0; n < nr_bhs; n++) { | |
366 | c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr); | |
367 | if (!c_bh) { | |
368 | err = -ENOMEM; | |
369 | goto error; | |
370 | } | |
371 | memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); | |
372 | set_buffer_uptodate(c_bh); | |
373 | mark_buffer_dirty(c_bh); | |
374 | if (sb->s_flags & MS_SYNCHRONOUS) | |
375 | err = sync_dirty_buffer(c_bh); | |
376 | brelse(c_bh); | |
377 | if (err) | |
378 | goto error; | |
379 | } | |
380 | } | |
381 | error: | |
382 | return err; | |
383 | } | |
384 | ||
385 | int fat_ent_write(struct inode *inode, struct fat_entry *fatent, | |
386 | int new, int wait) | |
387 | { | |
388 | struct super_block *sb = inode->i_sb; | |
389 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
390 | int err; | |
391 | ||
392 | ops->ent_put(fatent, new); | |
393 | if (wait) { | |
394 | err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs); | |
395 | if (err) | |
396 | return err; | |
397 | } | |
398 | return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs); | |
399 | } | |
400 | ||
401 | static inline int fat_ent_next(struct msdos_sb_info *sbi, | |
402 | struct fat_entry *fatent) | |
403 | { | |
404 | if (sbi->fatent_ops->ent_next(fatent)) { | |
405 | if (fatent->entry < sbi->max_cluster) | |
406 | return 1; | |
407 | } | |
408 | return 0; | |
409 | } | |
410 | ||
411 | static inline int fat_ent_read_block(struct super_block *sb, | |
412 | struct fat_entry *fatent) | |
413 | { | |
414 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
415 | sector_t blocknr; | |
416 | int offset; | |
417 | ||
418 | fatent_brelse(fatent); | |
419 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
420 | return ops->ent_bread(sb, fatent, offset, blocknr); | |
421 | } | |
422 | ||
423 | static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs, | |
424 | struct fat_entry *fatent) | |
425 | { | |
426 | int n, i; | |
427 | ||
428 | for (n = 0; n < fatent->nr_bhs; n++) { | |
429 | for (i = 0; i < *nr_bhs; i++) { | |
430 | if (fatent->bhs[n] == bhs[i]) | |
431 | break; | |
432 | } | |
433 | if (i == *nr_bhs) { | |
434 | get_bh(fatent->bhs[n]); | |
435 | bhs[i] = fatent->bhs[n]; | |
436 | (*nr_bhs)++; | |
437 | } | |
438 | } | |
439 | } | |
440 | ||
441 | int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster) | |
442 | { | |
443 | struct super_block *sb = inode->i_sb; | |
444 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
445 | struct fatent_operations *ops = sbi->fatent_ops; | |
446 | struct fat_entry fatent, prev_ent; | |
447 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
448 | int i, count, err, nr_bhs, idx_clus; | |
449 | ||
450 | BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */ | |
451 | ||
452 | lock_fat(sbi); | |
606e423e OH |
453 | if (sbi->free_clusters != -1 && sbi->free_clus_valid && |
454 | sbi->free_clusters < nr_cluster) { | |
1da177e4 LT |
455 | unlock_fat(sbi); |
456 | return -ENOSPC; | |
457 | } | |
458 | ||
459 | err = nr_bhs = idx_clus = 0; | |
460 | count = FAT_START_ENT; | |
461 | fatent_init(&prev_ent); | |
462 | fatent_init(&fatent); | |
463 | fatent_set_entry(&fatent, sbi->prev_free + 1); | |
464 | while (count < sbi->max_cluster) { | |
465 | if (fatent.entry >= sbi->max_cluster) | |
466 | fatent.entry = FAT_START_ENT; | |
467 | fatent_set_entry(&fatent, fatent.entry); | |
468 | err = fat_ent_read_block(sb, &fatent); | |
469 | if (err) | |
470 | goto out; | |
471 | ||
472 | /* Find the free entries in a block */ | |
473 | do { | |
474 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) { | |
475 | int entry = fatent.entry; | |
476 | ||
477 | /* make the cluster chain */ | |
478 | ops->ent_put(&fatent, FAT_ENT_EOF); | |
479 | if (prev_ent.nr_bhs) | |
480 | ops->ent_put(&prev_ent, entry); | |
481 | ||
482 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
483 | ||
484 | sbi->prev_free = entry; | |
485 | if (sbi->free_clusters != -1) | |
486 | sbi->free_clusters--; | |
a6bf6b21 | 487 | sb->s_dirt = 1; |
1da177e4 LT |
488 | |
489 | cluster[idx_clus] = entry; | |
490 | idx_clus++; | |
491 | if (idx_clus == nr_cluster) | |
492 | goto out; | |
493 | ||
494 | /* | |
495 | * fat_collect_bhs() gets ref-count of bhs, | |
496 | * so we can still use the prev_ent. | |
497 | */ | |
498 | prev_ent = fatent; | |
499 | } | |
500 | count++; | |
501 | if (count == sbi->max_cluster) | |
502 | break; | |
503 | } while (fat_ent_next(sbi, &fatent)); | |
504 | } | |
505 | ||
506 | /* Couldn't allocate the free entries */ | |
507 | sbi->free_clusters = 0; | |
606e423e | 508 | sbi->free_clus_valid = 1; |
a6bf6b21 | 509 | sb->s_dirt = 1; |
1da177e4 LT |
510 | err = -ENOSPC; |
511 | ||
512 | out: | |
513 | unlock_fat(sbi); | |
514 | fatent_brelse(&fatent); | |
515 | if (!err) { | |
516 | if (inode_needs_sync(inode)) | |
517 | err = fat_sync_bhs(bhs, nr_bhs); | |
518 | if (!err) | |
519 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
520 | } | |
521 | for (i = 0; i < nr_bhs; i++) | |
522 | brelse(bhs[i]); | |
1da177e4 LT |
523 | |
524 | if (err && idx_clus) | |
525 | fat_free_clusters(inode, cluster[0]); | |
526 | ||
527 | return err; | |
528 | } | |
529 | ||
530 | int fat_free_clusters(struct inode *inode, int cluster) | |
531 | { | |
532 | struct super_block *sb = inode->i_sb; | |
533 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
534 | struct fatent_operations *ops = sbi->fatent_ops; | |
535 | struct fat_entry fatent; | |
536 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
537 | int i, err, nr_bhs; | |
538 | ||
539 | nr_bhs = 0; | |
540 | fatent_init(&fatent); | |
541 | lock_fat(sbi); | |
542 | do { | |
543 | cluster = fat_ent_read(inode, &fatent, cluster); | |
544 | if (cluster < 0) { | |
545 | err = cluster; | |
546 | goto error; | |
547 | } else if (cluster == FAT_ENT_FREE) { | |
548 | fat_fs_panic(sb, "%s: deleting FAT entry beyond EOF", | |
8e24eea7 | 549 | __func__); |
1da177e4 LT |
550 | err = -EIO; |
551 | goto error; | |
552 | } | |
553 | ||
554 | ops->ent_put(&fatent, FAT_ENT_FREE); | |
a6bf6b21 | 555 | if (sbi->free_clusters != -1) { |
1da177e4 | 556 | sbi->free_clusters++; |
a6bf6b21 OH |
557 | sb->s_dirt = 1; |
558 | } | |
1da177e4 LT |
559 | |
560 | if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) { | |
561 | if (sb->s_flags & MS_SYNCHRONOUS) { | |
562 | err = fat_sync_bhs(bhs, nr_bhs); | |
563 | if (err) | |
564 | goto error; | |
565 | } | |
566 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
567 | if (err) | |
568 | goto error; | |
569 | for (i = 0; i < nr_bhs; i++) | |
570 | brelse(bhs[i]); | |
571 | nr_bhs = 0; | |
572 | } | |
573 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
574 | } while (cluster != FAT_ENT_EOF); | |
575 | ||
576 | if (sb->s_flags & MS_SYNCHRONOUS) { | |
577 | err = fat_sync_bhs(bhs, nr_bhs); | |
578 | if (err) | |
579 | goto error; | |
580 | } | |
581 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
582 | error: | |
583 | fatent_brelse(&fatent); | |
584 | for (i = 0; i < nr_bhs; i++) | |
585 | brelse(bhs[i]); | |
586 | unlock_fat(sbi); | |
587 | ||
1da177e4 LT |
588 | return err; |
589 | } | |
590 | ||
7c709d00 | 591 | EXPORT_SYMBOL_GPL(fat_free_clusters); |
1da177e4 | 592 | |
9f966be8 OH |
593 | /* 128kb is the whole sectors for FAT12 and FAT16 */ |
594 | #define FAT_READA_SIZE (128 * 1024) | |
595 | ||
596 | static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent, | |
597 | unsigned long reada_blocks) | |
598 | { | |
599 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
600 | sector_t blocknr; | |
601 | int i, offset; | |
602 | ||
603 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
604 | ||
605 | for (i = 0; i < reada_blocks; i++) | |
606 | sb_breadahead(sb, blocknr + i); | |
607 | } | |
608 | ||
1da177e4 LT |
609 | int fat_count_free_clusters(struct super_block *sb) |
610 | { | |
611 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
612 | struct fatent_operations *ops = sbi->fatent_ops; | |
613 | struct fat_entry fatent; | |
9f966be8 | 614 | unsigned long reada_blocks, reada_mask, cur_block; |
1da177e4 LT |
615 | int err = 0, free; |
616 | ||
617 | lock_fat(sbi); | |
606e423e | 618 | if (sbi->free_clusters != -1 && sbi->free_clus_valid) |
1da177e4 LT |
619 | goto out; |
620 | ||
9f966be8 OH |
621 | reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits; |
622 | reada_mask = reada_blocks - 1; | |
623 | cur_block = 0; | |
624 | ||
1da177e4 LT |
625 | free = 0; |
626 | fatent_init(&fatent); | |
627 | fatent_set_entry(&fatent, FAT_START_ENT); | |
628 | while (fatent.entry < sbi->max_cluster) { | |
9f966be8 OH |
629 | /* readahead of fat blocks */ |
630 | if ((cur_block & reada_mask) == 0) { | |
631 | unsigned long rest = sbi->fat_length - cur_block; | |
632 | fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); | |
633 | } | |
634 | cur_block++; | |
635 | ||
1da177e4 LT |
636 | err = fat_ent_read_block(sb, &fatent); |
637 | if (err) | |
638 | goto out; | |
639 | ||
640 | do { | |
641 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) | |
642 | free++; | |
643 | } while (fat_ent_next(sbi, &fatent)); | |
644 | } | |
645 | sbi->free_clusters = free; | |
606e423e | 646 | sbi->free_clus_valid = 1; |
a6bf6b21 | 647 | sb->s_dirt = 1; |
1da177e4 LT |
648 | fatent_brelse(&fatent); |
649 | out: | |
650 | unlock_fat(sbi); | |
651 | return err; | |
652 | } |