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> | |
8c540a96 | 9 | #include <linux/blkdev.h> |
1da177e4 LT |
10 | |
11 | struct fatent_operations { | |
12 | void (*ent_blocknr)(struct super_block *, int, int *, sector_t *); | |
13 | void (*ent_set_ptr)(struct fat_entry *, int); | |
14 | int (*ent_bread)(struct super_block *, struct fat_entry *, | |
15 | int, sector_t); | |
16 | int (*ent_get)(struct fat_entry *); | |
17 | void (*ent_put)(struct fat_entry *, int); | |
18 | int (*ent_next)(struct fat_entry *); | |
19 | }; | |
20 | ||
98283bb4 OH |
21 | static DEFINE_SPINLOCK(fat12_entry_lock); |
22 | ||
1da177e4 LT |
23 | static void fat12_ent_blocknr(struct super_block *sb, int entry, |
24 | int *offset, sector_t *blocknr) | |
25 | { | |
26 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
27 | int bytes = entry + (entry >> 1); | |
28 | WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry); | |
29 | *offset = bytes & (sb->s_blocksize - 1); | |
30 | *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); | |
31 | } | |
32 | ||
33 | static void fat_ent_blocknr(struct super_block *sb, int entry, | |
34 | int *offset, sector_t *blocknr) | |
35 | { | |
36 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
37 | int bytes = (entry << sbi->fatent_shift); | |
38 | WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry); | |
39 | *offset = bytes & (sb->s_blocksize - 1); | |
40 | *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); | |
41 | } | |
42 | ||
43 | static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset) | |
44 | { | |
45 | struct buffer_head **bhs = fatent->bhs; | |
46 | if (fatent->nr_bhs == 1) { | |
47 | WARN_ON(offset >= (bhs[0]->b_size - 1)); | |
48 | fatent->u.ent12_p[0] = bhs[0]->b_data + offset; | |
49 | fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1); | |
50 | } else { | |
51 | WARN_ON(offset != (bhs[0]->b_size - 1)); | |
52 | fatent->u.ent12_p[0] = bhs[0]->b_data + offset; | |
53 | fatent->u.ent12_p[1] = bhs[1]->b_data; | |
54 | } | |
55 | } | |
56 | ||
57 | static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset) | |
58 | { | |
59 | WARN_ON(offset & (2 - 1)); | |
60 | fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset); | |
61 | } | |
62 | ||
63 | static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset) | |
64 | { | |
65 | WARN_ON(offset & (4 - 1)); | |
66 | fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset); | |
67 | } | |
68 | ||
69 | static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent, | |
70 | int offset, sector_t blocknr) | |
71 | { | |
72 | struct buffer_head **bhs = fatent->bhs; | |
73 | ||
74 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
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: | |
95 | printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n", | |
96 | (unsigned long long)blocknr); | |
97 | return -EIO; | |
98 | } | |
99 | ||
100 | static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent, | |
101 | int offset, sector_t blocknr) | |
102 | { | |
103 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
104 | ||
105 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
106 | fatent->bhs[0] = sb_bread(sb, blocknr); | |
107 | if (!fatent->bhs[0]) { | |
108 | printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n", | |
109 | (unsigned long long)blocknr); | |
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 LT |
169 | |
170 | mark_buffer_dirty(fatent->bhs[0]); | |
171 | if (fatent->nr_bhs == 2) | |
172 | mark_buffer_dirty(fatent->bhs[1]); | |
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); | |
181 | mark_buffer_dirty(fatent->bhs[0]); | |
182 | } | |
183 | ||
184 | static void fat32_ent_put(struct fat_entry *fatent, int new) | |
185 | { | |
186 | if (new == FAT_ENT_EOF) | |
187 | new = EOF_FAT32; | |
188 | ||
189 | WARN_ON(new & 0xf0000000); | |
190 | new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; | |
191 | *fatent->u.ent32_p = cpu_to_le32(new); | |
192 | mark_buffer_dirty(fatent->bhs[0]); | |
193 | } | |
194 | ||
195 | static int fat12_ent_next(struct fat_entry *fatent) | |
196 | { | |
197 | u8 **ent12_p = fatent->u.ent12_p; | |
198 | struct buffer_head **bhs = fatent->bhs; | |
199 | u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1); | |
200 | ||
201 | fatent->entry++; | |
202 | if (fatent->nr_bhs == 1) { | |
203 | WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 2))); | |
204 | WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))); | |
205 | if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) { | |
206 | ent12_p[0] = nextp - 1; | |
207 | ent12_p[1] = nextp; | |
208 | return 1; | |
209 | } | |
210 | } else { | |
211 | WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))); | |
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 | ||
249 | static struct fatent_operations fat12_ops = { | |
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 | ||
258 | static struct fatent_operations fat16_ops = { | |
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 | ||
267 | static struct fatent_operations fat32_ops = { | |
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 | ||
308 | static inline int fat_ent_update_ptr(struct super_block *sb, | |
309 | struct fat_entry *fatent, | |
310 | int offset, sector_t blocknr) | |
311 | { | |
312 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
313 | struct fatent_operations *ops = sbi->fatent_ops; | |
314 | struct buffer_head **bhs = fatent->bhs; | |
315 | ||
316 | /* Is this fatent's blocks including this entry? */ | |
317 | if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr) | |
318 | return 0; | |
319 | /* Does this entry need the next block? */ | |
320 | if (sbi->fat_bits == 12 && (offset + 1) >= sb->s_blocksize) { | |
321 | if (fatent->nr_bhs != 2 || bhs[1]->b_blocknr != (blocknr + 1)) | |
322 | return 0; | |
323 | } | |
324 | ops->ent_set_ptr(fatent, offset); | |
325 | return 1; | |
326 | } | |
327 | ||
328 | int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry) | |
329 | { | |
330 | struct super_block *sb = inode->i_sb; | |
331 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); | |
332 | struct fatent_operations *ops = sbi->fatent_ops; | |
333 | int err, offset; | |
334 | sector_t blocknr; | |
335 | ||
336 | if (entry < FAT_START_ENT || sbi->max_cluster <= entry) { | |
337 | fatent_brelse(fatent); | |
338 | fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", entry); | |
339 | return -EIO; | |
340 | } | |
341 | ||
342 | fatent_set_entry(fatent, entry); | |
343 | ops->ent_blocknr(sb, entry, &offset, &blocknr); | |
344 | ||
345 | if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) { | |
346 | fatent_brelse(fatent); | |
347 | err = ops->ent_bread(sb, fatent, offset, blocknr); | |
348 | if (err) | |
349 | return err; | |
350 | } | |
351 | return ops->ent_get(fatent); | |
352 | } | |
353 | ||
354 | /* FIXME: We can write the blocks as more big chunk. */ | |
355 | static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, | |
356 | int nr_bhs) | |
357 | { | |
358 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
359 | struct buffer_head *c_bh; | |
360 | int err, n, copy; | |
361 | ||
362 | err = 0; | |
363 | for (copy = 1; copy < sbi->fats; copy++) { | |
364 | sector_t backup_fat = sbi->fat_length * copy; | |
365 | ||
366 | for (n = 0; n < nr_bhs; n++) { | |
367 | c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr); | |
368 | if (!c_bh) { | |
369 | err = -ENOMEM; | |
370 | goto error; | |
371 | } | |
372 | memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); | |
373 | set_buffer_uptodate(c_bh); | |
374 | mark_buffer_dirty(c_bh); | |
375 | if (sb->s_flags & MS_SYNCHRONOUS) | |
376 | err = sync_dirty_buffer(c_bh); | |
377 | brelse(c_bh); | |
378 | if (err) | |
379 | goto error; | |
380 | } | |
381 | } | |
382 | error: | |
383 | return err; | |
384 | } | |
385 | ||
386 | int fat_ent_write(struct inode *inode, struct fat_entry *fatent, | |
387 | int new, int wait) | |
388 | { | |
389 | struct super_block *sb = inode->i_sb; | |
390 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
391 | int err; | |
392 | ||
393 | ops->ent_put(fatent, new); | |
394 | if (wait) { | |
395 | err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs); | |
396 | if (err) | |
397 | return err; | |
398 | } | |
399 | return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs); | |
400 | } | |
401 | ||
402 | static inline int fat_ent_next(struct msdos_sb_info *sbi, | |
403 | struct fat_entry *fatent) | |
404 | { | |
405 | if (sbi->fatent_ops->ent_next(fatent)) { | |
406 | if (fatent->entry < sbi->max_cluster) | |
407 | return 1; | |
408 | } | |
409 | return 0; | |
410 | } | |
411 | ||
412 | static inline int fat_ent_read_block(struct super_block *sb, | |
413 | struct fat_entry *fatent) | |
414 | { | |
415 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
416 | sector_t blocknr; | |
417 | int offset; | |
418 | ||
419 | fatent_brelse(fatent); | |
420 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
421 | return ops->ent_bread(sb, fatent, offset, blocknr); | |
422 | } | |
423 | ||
424 | static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs, | |
425 | struct fat_entry *fatent) | |
426 | { | |
427 | int n, i; | |
428 | ||
429 | for (n = 0; n < fatent->nr_bhs; n++) { | |
430 | for (i = 0; i < *nr_bhs; i++) { | |
431 | if (fatent->bhs[n] == bhs[i]) | |
432 | break; | |
433 | } | |
434 | if (i == *nr_bhs) { | |
435 | get_bh(fatent->bhs[n]); | |
436 | bhs[i] = fatent->bhs[n]; | |
437 | (*nr_bhs)++; | |
438 | } | |
439 | } | |
440 | } | |
441 | ||
442 | int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster) | |
443 | { | |
444 | struct super_block *sb = inode->i_sb; | |
445 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
446 | struct fatent_operations *ops = sbi->fatent_ops; | |
447 | struct fat_entry fatent, prev_ent; | |
448 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
449 | int i, count, err, nr_bhs, idx_clus; | |
450 | ||
451 | BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */ | |
452 | ||
453 | lock_fat(sbi); | |
606e423e OH |
454 | if (sbi->free_clusters != -1 && sbi->free_clus_valid && |
455 | sbi->free_clusters < nr_cluster) { | |
1da177e4 LT |
456 | unlock_fat(sbi); |
457 | return -ENOSPC; | |
458 | } | |
459 | ||
460 | err = nr_bhs = idx_clus = 0; | |
461 | count = FAT_START_ENT; | |
462 | fatent_init(&prev_ent); | |
463 | fatent_init(&fatent); | |
464 | fatent_set_entry(&fatent, sbi->prev_free + 1); | |
465 | while (count < sbi->max_cluster) { | |
466 | if (fatent.entry >= sbi->max_cluster) | |
467 | fatent.entry = FAT_START_ENT; | |
468 | fatent_set_entry(&fatent, fatent.entry); | |
469 | err = fat_ent_read_block(sb, &fatent); | |
470 | if (err) | |
471 | goto out; | |
472 | ||
473 | /* Find the free entries in a block */ | |
474 | do { | |
475 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) { | |
476 | int entry = fatent.entry; | |
477 | ||
478 | /* make the cluster chain */ | |
479 | ops->ent_put(&fatent, FAT_ENT_EOF); | |
480 | if (prev_ent.nr_bhs) | |
481 | ops->ent_put(&prev_ent, entry); | |
482 | ||
483 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
484 | ||
485 | sbi->prev_free = entry; | |
486 | if (sbi->free_clusters != -1) | |
487 | sbi->free_clusters--; | |
a6bf6b21 | 488 | sb->s_dirt = 1; |
1da177e4 LT |
489 | |
490 | cluster[idx_clus] = entry; | |
491 | idx_clus++; | |
492 | if (idx_clus == nr_cluster) | |
493 | goto out; | |
494 | ||
495 | /* | |
496 | * fat_collect_bhs() gets ref-count of bhs, | |
497 | * so we can still use the prev_ent. | |
498 | */ | |
499 | prev_ent = fatent; | |
500 | } | |
501 | count++; | |
502 | if (count == sbi->max_cluster) | |
503 | break; | |
504 | } while (fat_ent_next(sbi, &fatent)); | |
505 | } | |
506 | ||
507 | /* Couldn't allocate the free entries */ | |
508 | sbi->free_clusters = 0; | |
606e423e | 509 | sbi->free_clus_valid = 1; |
a6bf6b21 | 510 | sb->s_dirt = 1; |
1da177e4 LT |
511 | err = -ENOSPC; |
512 | ||
513 | out: | |
514 | unlock_fat(sbi); | |
515 | fatent_brelse(&fatent); | |
516 | if (!err) { | |
517 | if (inode_needs_sync(inode)) | |
518 | err = fat_sync_bhs(bhs, nr_bhs); | |
519 | if (!err) | |
520 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
521 | } | |
522 | for (i = 0; i < nr_bhs; i++) | |
523 | brelse(bhs[i]); | |
1da177e4 LT |
524 | |
525 | if (err && idx_clus) | |
526 | fat_free_clusters(inode, cluster[0]); | |
527 | ||
528 | return err; | |
529 | } | |
530 | ||
531 | int fat_free_clusters(struct inode *inode, int cluster) | |
532 | { | |
533 | struct super_block *sb = inode->i_sb; | |
534 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
535 | struct fatent_operations *ops = sbi->fatent_ops; | |
536 | struct fat_entry fatent; | |
537 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
538 | int i, err, nr_bhs; | |
8c540a96 | 539 | int first_cl = cluster; |
1da177e4 LT |
540 | |
541 | nr_bhs = 0; | |
542 | fatent_init(&fatent); | |
543 | lock_fat(sbi); | |
544 | do { | |
545 | cluster = fat_ent_read(inode, &fatent, cluster); | |
546 | if (cluster < 0) { | |
547 | err = cluster; | |
548 | goto error; | |
549 | } else if (cluster == FAT_ENT_FREE) { | |
550 | fat_fs_panic(sb, "%s: deleting FAT entry beyond EOF", | |
8e24eea7 | 551 | __func__); |
1da177e4 LT |
552 | err = -EIO; |
553 | goto error; | |
554 | } | |
555 | ||
8c540a96 DW |
556 | /* |
557 | * Issue discard for the sectors we no longer care about, | |
558 | * batching contiguous clusters into one request | |
559 | */ | |
560 | if (cluster != fatent.entry + 1) { | |
561 | int nr_clus = fatent.entry - first_cl + 1; | |
562 | ||
563 | sb_issue_discard(sb, fat_clus_to_blknr(sbi, first_cl), | |
564 | nr_clus * sbi->sec_per_clus); | |
565 | first_cl = cluster; | |
566 | } | |
567 | ||
1da177e4 | 568 | ops->ent_put(&fatent, FAT_ENT_FREE); |
a6bf6b21 | 569 | if (sbi->free_clusters != -1) { |
1da177e4 | 570 | sbi->free_clusters++; |
a6bf6b21 OH |
571 | sb->s_dirt = 1; |
572 | } | |
1da177e4 LT |
573 | |
574 | if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) { | |
575 | if (sb->s_flags & MS_SYNCHRONOUS) { | |
576 | err = fat_sync_bhs(bhs, nr_bhs); | |
577 | if (err) | |
578 | goto error; | |
579 | } | |
580 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
581 | if (err) | |
582 | goto error; | |
583 | for (i = 0; i < nr_bhs; i++) | |
584 | brelse(bhs[i]); | |
585 | nr_bhs = 0; | |
586 | } | |
587 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
588 | } while (cluster != FAT_ENT_EOF); | |
589 | ||
590 | if (sb->s_flags & MS_SYNCHRONOUS) { | |
591 | err = fat_sync_bhs(bhs, nr_bhs); | |
592 | if (err) | |
593 | goto error; | |
594 | } | |
595 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
596 | error: | |
597 | fatent_brelse(&fatent); | |
598 | for (i = 0; i < nr_bhs; i++) | |
599 | brelse(bhs[i]); | |
600 | unlock_fat(sbi); | |
601 | ||
1da177e4 LT |
602 | return err; |
603 | } | |
604 | ||
7c709d00 | 605 | EXPORT_SYMBOL_GPL(fat_free_clusters); |
1da177e4 | 606 | |
9f966be8 OH |
607 | /* 128kb is the whole sectors for FAT12 and FAT16 */ |
608 | #define FAT_READA_SIZE (128 * 1024) | |
609 | ||
610 | static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent, | |
611 | unsigned long reada_blocks) | |
612 | { | |
613 | struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; | |
614 | sector_t blocknr; | |
615 | int i, offset; | |
616 | ||
617 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
618 | ||
619 | for (i = 0; i < reada_blocks; i++) | |
620 | sb_breadahead(sb, blocknr + i); | |
621 | } | |
622 | ||
1da177e4 LT |
623 | int fat_count_free_clusters(struct super_block *sb) |
624 | { | |
625 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
626 | struct fatent_operations *ops = sbi->fatent_ops; | |
627 | struct fat_entry fatent; | |
9f966be8 | 628 | unsigned long reada_blocks, reada_mask, cur_block; |
1da177e4 LT |
629 | int err = 0, free; |
630 | ||
631 | lock_fat(sbi); | |
606e423e | 632 | if (sbi->free_clusters != -1 && sbi->free_clus_valid) |
1da177e4 LT |
633 | goto out; |
634 | ||
9f966be8 OH |
635 | reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits; |
636 | reada_mask = reada_blocks - 1; | |
637 | cur_block = 0; | |
638 | ||
1da177e4 LT |
639 | free = 0; |
640 | fatent_init(&fatent); | |
641 | fatent_set_entry(&fatent, FAT_START_ENT); | |
642 | while (fatent.entry < sbi->max_cluster) { | |
9f966be8 OH |
643 | /* readahead of fat blocks */ |
644 | if ((cur_block & reada_mask) == 0) { | |
645 | unsigned long rest = sbi->fat_length - cur_block; | |
646 | fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); | |
647 | } | |
648 | cur_block++; | |
649 | ||
1da177e4 LT |
650 | err = fat_ent_read_block(sb, &fatent); |
651 | if (err) | |
652 | goto out; | |
653 | ||
654 | do { | |
655 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) | |
656 | free++; | |
657 | } while (fat_ent_next(sbi, &fatent)); | |
658 | } | |
659 | sbi->free_clusters = free; | |
606e423e | 660 | sbi->free_clus_valid = 1; |
a6bf6b21 | 661 | sb->s_dirt = 1; |
1da177e4 LT |
662 | fatent_brelse(&fatent); |
663 | out: | |
664 | unlock_fat(sbi); | |
665 | return err; | |
666 | } |