Commit | Line | Data |
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59bd9ded | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * Copyright (C) 2004, OGAWA Hirofumi | |
1da177e4 LT |
4 | */ |
5 | ||
8c540a96 | 6 | #include <linux/blkdev.h> |
f663b5b3 | 7 | #include <linux/sched/signal.h> |
edb0872f | 8 | #include <linux/backing-dev-defs.h> |
9e975dae | 9 | #include "fat.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); | |
0afa9626 | 28 | WARN_ON(!fat_valid_entry(sbi, entry)); |
1da177e4 LT |
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); | |
0afa9626 | 38 | WARN_ON(!fat_valid_entry(sbi, entry)); |
1da177e4 LT |
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); | |
b522412a AV |
75 | fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
76 | ||
1da177e4 LT |
77 | bhs[0] = sb_bread(sb, blocknr); |
78 | if (!bhs[0]) | |
79 | goto err; | |
80 | ||
81 | if ((offset + 1) < sb->s_blocksize) | |
82 | fatent->nr_bhs = 1; | |
83 | else { | |
84 | /* This entry is block boundary, it needs the next block */ | |
85 | blocknr++; | |
86 | bhs[1] = sb_bread(sb, blocknr); | |
87 | if (!bhs[1]) | |
88 | goto err_brelse; | |
89 | fatent->nr_bhs = 2; | |
90 | } | |
91 | fat12_ent_set_ptr(fatent, offset); | |
92 | return 0; | |
93 | ||
94 | err_brelse: | |
95 | brelse(bhs[0]); | |
96 | err: | |
183c3237 OH |
97 | fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)", |
98 | (llu)blocknr); | |
1da177e4 LT |
99 | return -EIO; |
100 | } | |
101 | ||
102 | static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent, | |
103 | int offset, sector_t blocknr) | |
104 | { | |
8992de4c | 105 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
1da177e4 LT |
106 | |
107 | WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); | |
b522412a | 108 | fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
1da177e4 LT |
109 | fatent->bhs[0] = sb_bread(sb, blocknr); |
110 | if (!fatent->bhs[0]) { | |
183c3237 OH |
111 | fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)", |
112 | (llu)blocknr); | |
1da177e4 LT |
113 | return -EIO; |
114 | } | |
115 | fatent->nr_bhs = 1; | |
116 | ops->ent_set_ptr(fatent, offset); | |
117 | return 0; | |
118 | } | |
119 | ||
120 | static int fat12_ent_get(struct fat_entry *fatent) | |
121 | { | |
122 | u8 **ent12_p = fatent->u.ent12_p; | |
123 | int next; | |
124 | ||
98283bb4 | 125 | spin_lock(&fat12_entry_lock); |
1da177e4 LT |
126 | if (fatent->entry & 1) |
127 | next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4); | |
128 | else | |
129 | next = (*ent12_p[1] << 8) | *ent12_p[0]; | |
98283bb4 OH |
130 | spin_unlock(&fat12_entry_lock); |
131 | ||
1da177e4 LT |
132 | next &= 0x0fff; |
133 | if (next >= BAD_FAT12) | |
134 | next = FAT_ENT_EOF; | |
135 | return next; | |
136 | } | |
137 | ||
138 | static int fat16_ent_get(struct fat_entry *fatent) | |
139 | { | |
140 | int next = le16_to_cpu(*fatent->u.ent16_p); | |
141 | WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1)); | |
142 | if (next >= BAD_FAT16) | |
143 | next = FAT_ENT_EOF; | |
144 | return next; | |
145 | } | |
146 | ||
147 | static int fat32_ent_get(struct fat_entry *fatent) | |
148 | { | |
149 | int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff; | |
150 | WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1)); | |
151 | if (next >= BAD_FAT32) | |
152 | next = FAT_ENT_EOF; | |
153 | return next; | |
154 | } | |
155 | ||
156 | static void fat12_ent_put(struct fat_entry *fatent, int new) | |
157 | { | |
158 | u8 **ent12_p = fatent->u.ent12_p; | |
159 | ||
160 | if (new == FAT_ENT_EOF) | |
161 | new = EOF_FAT12; | |
162 | ||
98283bb4 | 163 | spin_lock(&fat12_entry_lock); |
1da177e4 LT |
164 | if (fatent->entry & 1) { |
165 | *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f); | |
166 | *ent12_p[1] = new >> 4; | |
167 | } else { | |
168 | *ent12_p[0] = new & 0xff; | |
169 | *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8); | |
170 | } | |
98283bb4 | 171 | spin_unlock(&fat12_entry_lock); |
1da177e4 | 172 | |
b522412a | 173 | mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
1da177e4 | 174 | if (fatent->nr_bhs == 2) |
b522412a | 175 | mark_buffer_dirty_inode(fatent->bhs[1], fatent->fat_inode); |
1da177e4 LT |
176 | } |
177 | ||
178 | static void fat16_ent_put(struct fat_entry *fatent, int new) | |
179 | { | |
180 | if (new == FAT_ENT_EOF) | |
181 | new = EOF_FAT16; | |
182 | ||
183 | *fatent->u.ent16_p = cpu_to_le16(new); | |
b522412a | 184 | mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
1da177e4 LT |
185 | } |
186 | ||
187 | static void fat32_ent_put(struct fat_entry *fatent, int new) | |
188 | { | |
1da177e4 LT |
189 | WARN_ON(new & 0xf0000000); |
190 | new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; | |
191 | *fatent->u.ent32_p = cpu_to_le32(new); | |
b522412a | 192 | mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
1da177e4 LT |
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) { | |
441dff34 CJB |
203 | WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + |
204 | (bhs[0]->b_size - 2))); | |
205 | WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + | |
206 | (bhs[0]->b_size - 1))); | |
1da177e4 LT |
207 | if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) { |
208 | ent12_p[0] = nextp - 1; | |
209 | ent12_p[1] = nextp; | |
210 | return 1; | |
211 | } | |
212 | } else { | |
441dff34 CJB |
213 | WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + |
214 | (bhs[0]->b_size - 1))); | |
1da177e4 LT |
215 | WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data); |
216 | ent12_p[0] = nextp - 1; | |
217 | ent12_p[1] = nextp; | |
218 | brelse(bhs[0]); | |
219 | bhs[0] = bhs[1]; | |
220 | fatent->nr_bhs = 1; | |
221 | return 1; | |
222 | } | |
223 | ent12_p[0] = NULL; | |
224 | ent12_p[1] = NULL; | |
225 | return 0; | |
226 | } | |
227 | ||
228 | static int fat16_ent_next(struct fat_entry *fatent) | |
229 | { | |
230 | const struct buffer_head *bh = fatent->bhs[0]; | |
231 | fatent->entry++; | |
232 | if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) { | |
233 | fatent->u.ent16_p++; | |
234 | return 1; | |
235 | } | |
236 | fatent->u.ent16_p = NULL; | |
237 | return 0; | |
238 | } | |
239 | ||
240 | static int fat32_ent_next(struct fat_entry *fatent) | |
241 | { | |
242 | const struct buffer_head *bh = fatent->bhs[0]; | |
243 | fatent->entry++; | |
244 | if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) { | |
245 | fatent->u.ent32_p++; | |
246 | return 1; | |
247 | } | |
248 | fatent->u.ent32_p = NULL; | |
249 | return 0; | |
250 | } | |
251 | ||
8992de4c | 252 | static const struct fatent_operations fat12_ops = { |
1da177e4 LT |
253 | .ent_blocknr = fat12_ent_blocknr, |
254 | .ent_set_ptr = fat12_ent_set_ptr, | |
255 | .ent_bread = fat12_ent_bread, | |
256 | .ent_get = fat12_ent_get, | |
257 | .ent_put = fat12_ent_put, | |
258 | .ent_next = fat12_ent_next, | |
259 | }; | |
260 | ||
8992de4c | 261 | static const struct fatent_operations fat16_ops = { |
1da177e4 LT |
262 | .ent_blocknr = fat_ent_blocknr, |
263 | .ent_set_ptr = fat16_ent_set_ptr, | |
264 | .ent_bread = fat_ent_bread, | |
265 | .ent_get = fat16_ent_get, | |
266 | .ent_put = fat16_ent_put, | |
267 | .ent_next = fat16_ent_next, | |
268 | }; | |
269 | ||
8992de4c | 270 | static const struct fatent_operations fat32_ops = { |
1da177e4 LT |
271 | .ent_blocknr = fat_ent_blocknr, |
272 | .ent_set_ptr = fat32_ent_set_ptr, | |
273 | .ent_bread = fat_ent_bread, | |
274 | .ent_get = fat32_ent_get, | |
275 | .ent_put = fat32_ent_put, | |
276 | .ent_next = fat32_ent_next, | |
277 | }; | |
278 | ||
279 | static inline void lock_fat(struct msdos_sb_info *sbi) | |
280 | { | |
6b9438e1 | 281 | mutex_lock(&sbi->fat_lock); |
1da177e4 LT |
282 | } |
283 | ||
284 | static inline void unlock_fat(struct msdos_sb_info *sbi) | |
285 | { | |
6b9438e1 | 286 | mutex_unlock(&sbi->fat_lock); |
1da177e4 LT |
287 | } |
288 | ||
289 | void fat_ent_access_init(struct super_block *sb) | |
290 | { | |
291 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
292 | ||
6b9438e1 | 293 | mutex_init(&sbi->fat_lock); |
1da177e4 | 294 | |
306790f7 | 295 | if (is_fat32(sbi)) { |
1da177e4 LT |
296 | sbi->fatent_shift = 2; |
297 | sbi->fatent_ops = &fat32_ops; | |
306790f7 | 298 | } else if (is_fat16(sbi)) { |
1da177e4 LT |
299 | sbi->fatent_shift = 1; |
300 | sbi->fatent_ops = &fat16_ops; | |
306790f7 | 301 | } else if (is_fat12(sbi)) { |
1da177e4 LT |
302 | sbi->fatent_shift = -1; |
303 | sbi->fatent_ops = &fat12_ops; | |
306790f7 CT |
304 | } else { |
305 | fat_fs_error(sb, "invalid FAT variant, %u bits", sbi->fat_bits); | |
1da177e4 LT |
306 | } |
307 | } | |
308 | ||
90b43665 AB |
309 | static void mark_fsinfo_dirty(struct super_block *sb) |
310 | { | |
78491189 AB |
311 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
312 | ||
306790f7 | 313 | if (sb_rdonly(sb) || !is_fat32(sbi)) |
78491189 AB |
314 | return; |
315 | ||
316 | __mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC); | |
90b43665 AB |
317 | } |
318 | ||
1da177e4 LT |
319 | static inline int fat_ent_update_ptr(struct super_block *sb, |
320 | struct fat_entry *fatent, | |
321 | int offset, sector_t blocknr) | |
322 | { | |
323 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 324 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
325 | struct buffer_head **bhs = fatent->bhs; |
326 | ||
327 | /* Is this fatent's blocks including this entry? */ | |
328 | if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr) | |
329 | return 0; | |
306790f7 | 330 | if (is_fat12(sbi)) { |
5e35dd46 OH |
331 | if ((offset + 1) < sb->s_blocksize) { |
332 | /* This entry is on bhs[0]. */ | |
333 | if (fatent->nr_bhs == 2) { | |
334 | brelse(bhs[1]); | |
335 | fatent->nr_bhs = 1; | |
336 | } | |
337 | } else { | |
338 | /* This entry needs the next block. */ | |
339 | if (fatent->nr_bhs != 2) | |
340 | return 0; | |
341 | if (bhs[1]->b_blocknr != (blocknr + 1)) | |
342 | return 0; | |
343 | } | |
1da177e4 LT |
344 | } |
345 | ops->ent_set_ptr(fatent, offset); | |
346 | return 1; | |
347 | } | |
348 | ||
349 | int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry) | |
350 | { | |
351 | struct super_block *sb = inode->i_sb; | |
352 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); | |
8992de4c | 353 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
354 | int err, offset; |
355 | sector_t blocknr; | |
356 | ||
0afa9626 | 357 | if (!fat_valid_entry(sbi, entry)) { |
1da177e4 | 358 | fatent_brelse(fatent); |
85c78591 | 359 | fat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", entry); |
1da177e4 LT |
360 | return -EIO; |
361 | } | |
362 | ||
363 | fatent_set_entry(fatent, entry); | |
364 | ops->ent_blocknr(sb, entry, &offset, &blocknr); | |
365 | ||
366 | if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) { | |
367 | fatent_brelse(fatent); | |
368 | err = ops->ent_bread(sb, fatent, offset, blocknr); | |
369 | if (err) | |
370 | return err; | |
371 | } | |
372 | return ops->ent_get(fatent); | |
373 | } | |
374 | ||
375 | /* FIXME: We can write the blocks as more big chunk. */ | |
376 | static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, | |
377 | int nr_bhs) | |
378 | { | |
379 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
380 | struct buffer_head *c_bh; | |
381 | int err, n, copy; | |
382 | ||
383 | err = 0; | |
384 | for (copy = 1; copy < sbi->fats; copy++) { | |
385 | sector_t backup_fat = sbi->fat_length * copy; | |
386 | ||
387 | for (n = 0; n < nr_bhs; n++) { | |
388 | c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr); | |
389 | if (!c_bh) { | |
390 | err = -ENOMEM; | |
391 | goto error; | |
392 | } | |
07bfa441 OH |
393 | /* Avoid race with userspace read via bdev */ |
394 | lock_buffer(c_bh); | |
1da177e4 LT |
395 | memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); |
396 | set_buffer_uptodate(c_bh); | |
07bfa441 | 397 | unlock_buffer(c_bh); |
b522412a | 398 | mark_buffer_dirty_inode(c_bh, sbi->fat_inode); |
1751e8a6 | 399 | if (sb->s_flags & SB_SYNCHRONOUS) |
1da177e4 LT |
400 | err = sync_dirty_buffer(c_bh); |
401 | brelse(c_bh); | |
402 | if (err) | |
403 | goto error; | |
404 | } | |
405 | } | |
406 | error: | |
407 | return err; | |
408 | } | |
409 | ||
410 | int fat_ent_write(struct inode *inode, struct fat_entry *fatent, | |
411 | int new, int wait) | |
412 | { | |
413 | struct super_block *sb = inode->i_sb; | |
8992de4c | 414 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
1da177e4 LT |
415 | int err; |
416 | ||
417 | ops->ent_put(fatent, new); | |
418 | if (wait) { | |
419 | err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs); | |
420 | if (err) | |
421 | return err; | |
422 | } | |
423 | return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs); | |
424 | } | |
425 | ||
426 | static inline int fat_ent_next(struct msdos_sb_info *sbi, | |
427 | struct fat_entry *fatent) | |
428 | { | |
429 | if (sbi->fatent_ops->ent_next(fatent)) { | |
430 | if (fatent->entry < sbi->max_cluster) | |
431 | return 1; | |
432 | } | |
433 | return 0; | |
434 | } | |
435 | ||
436 | static inline int fat_ent_read_block(struct super_block *sb, | |
437 | struct fat_entry *fatent) | |
438 | { | |
8992de4c | 439 | const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
1da177e4 LT |
440 | sector_t blocknr; |
441 | int offset; | |
442 | ||
443 | fatent_brelse(fatent); | |
444 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
445 | return ops->ent_bread(sb, fatent, offset, blocknr); | |
446 | } | |
447 | ||
448 | static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs, | |
449 | struct fat_entry *fatent) | |
450 | { | |
451 | int n, i; | |
452 | ||
453 | for (n = 0; n < fatent->nr_bhs; n++) { | |
454 | for (i = 0; i < *nr_bhs; i++) { | |
455 | if (fatent->bhs[n] == bhs[i]) | |
456 | break; | |
457 | } | |
458 | if (i == *nr_bhs) { | |
459 | get_bh(fatent->bhs[n]); | |
460 | bhs[i] = fatent->bhs[n]; | |
461 | (*nr_bhs)++; | |
462 | } | |
463 | } | |
464 | } | |
465 | ||
466 | int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster) | |
467 | { | |
468 | struct super_block *sb = inode->i_sb; | |
469 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 470 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
471 | struct fat_entry fatent, prev_ent; |
472 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
473 | int i, count, err, nr_bhs, idx_clus; | |
474 | ||
475 | BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */ | |
476 | ||
477 | lock_fat(sbi); | |
606e423e OH |
478 | if (sbi->free_clusters != -1 && sbi->free_clus_valid && |
479 | sbi->free_clusters < nr_cluster) { | |
1da177e4 LT |
480 | unlock_fat(sbi); |
481 | return -ENOSPC; | |
482 | } | |
483 | ||
484 | err = nr_bhs = idx_clus = 0; | |
485 | count = FAT_START_ENT; | |
486 | fatent_init(&prev_ent); | |
487 | fatent_init(&fatent); | |
488 | fatent_set_entry(&fatent, sbi->prev_free + 1); | |
489 | while (count < sbi->max_cluster) { | |
490 | if (fatent.entry >= sbi->max_cluster) | |
491 | fatent.entry = FAT_START_ENT; | |
492 | fatent_set_entry(&fatent, fatent.entry); | |
493 | err = fat_ent_read_block(sb, &fatent); | |
494 | if (err) | |
495 | goto out; | |
496 | ||
497 | /* Find the free entries in a block */ | |
498 | do { | |
499 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) { | |
500 | int entry = fatent.entry; | |
501 | ||
502 | /* make the cluster chain */ | |
503 | ops->ent_put(&fatent, FAT_ENT_EOF); | |
504 | if (prev_ent.nr_bhs) | |
505 | ops->ent_put(&prev_ent, entry); | |
506 | ||
507 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
508 | ||
509 | sbi->prev_free = entry; | |
510 | if (sbi->free_clusters != -1) | |
511 | sbi->free_clusters--; | |
512 | ||
513 | cluster[idx_clus] = entry; | |
514 | idx_clus++; | |
515 | if (idx_clus == nr_cluster) | |
516 | goto out; | |
517 | ||
518 | /* | |
519 | * fat_collect_bhs() gets ref-count of bhs, | |
520 | * so we can still use the prev_ent. | |
521 | */ | |
522 | prev_ent = fatent; | |
523 | } | |
524 | count++; | |
525 | if (count == sbi->max_cluster) | |
526 | break; | |
527 | } while (fat_ent_next(sbi, &fatent)); | |
528 | } | |
529 | ||
530 | /* Couldn't allocate the free entries */ | |
531 | sbi->free_clusters = 0; | |
606e423e | 532 | sbi->free_clus_valid = 1; |
1da177e4 LT |
533 | err = -ENOSPC; |
534 | ||
535 | out: | |
536 | unlock_fat(sbi); | |
330fe3c4 | 537 | mark_fsinfo_dirty(sb); |
1da177e4 LT |
538 | fatent_brelse(&fatent); |
539 | if (!err) { | |
540 | if (inode_needs_sync(inode)) | |
541 | err = fat_sync_bhs(bhs, nr_bhs); | |
542 | if (!err) | |
543 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
544 | } | |
545 | for (i = 0; i < nr_bhs; i++) | |
546 | brelse(bhs[i]); | |
1da177e4 LT |
547 | |
548 | if (err && idx_clus) | |
549 | fat_free_clusters(inode, cluster[0]); | |
550 | ||
551 | return err; | |
552 | } | |
553 | ||
554 | int fat_free_clusters(struct inode *inode, int cluster) | |
555 | { | |
556 | struct super_block *sb = inode->i_sb; | |
557 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 558 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 LT |
559 | struct fat_entry fatent; |
560 | struct buffer_head *bhs[MAX_BUF_PER_PAGE]; | |
561 | int i, err, nr_bhs; | |
330fe3c4 | 562 | int first_cl = cluster, dirty_fsinfo = 0; |
1da177e4 LT |
563 | |
564 | nr_bhs = 0; | |
565 | fatent_init(&fatent); | |
566 | lock_fat(sbi); | |
567 | do { | |
568 | cluster = fat_ent_read(inode, &fatent, cluster); | |
569 | if (cluster < 0) { | |
570 | err = cluster; | |
571 | goto error; | |
572 | } else if (cluster == FAT_ENT_FREE) { | |
85c78591 | 573 | fat_fs_error(sb, "%s: deleting FAT entry beyond EOF", |
8e24eea7 | 574 | __func__); |
1da177e4 LT |
575 | err = -EIO; |
576 | goto error; | |
577 | } | |
578 | ||
681142f9 CH |
579 | if (sbi->options.discard) { |
580 | /* | |
581 | * Issue discard for the sectors we no longer | |
582 | * care about, batching contiguous clusters | |
583 | * into one request | |
584 | */ | |
585 | if (cluster != fatent.entry + 1) { | |
586 | int nr_clus = fatent.entry - first_cl + 1; | |
587 | ||
588 | sb_issue_discard(sb, | |
589 | fat_clus_to_blknr(sbi, first_cl), | |
2cf6d26a | 590 | nr_clus * sbi->sec_per_clus, |
dd3932ed | 591 | GFP_NOFS, 0); |
681142f9 CH |
592 | |
593 | first_cl = cluster; | |
594 | } | |
8c540a96 DW |
595 | } |
596 | ||
1da177e4 | 597 | ops->ent_put(&fatent, FAT_ENT_FREE); |
a6bf6b21 | 598 | if (sbi->free_clusters != -1) { |
1da177e4 | 599 | sbi->free_clusters++; |
330fe3c4 | 600 | dirty_fsinfo = 1; |
a6bf6b21 | 601 | } |
1da177e4 LT |
602 | |
603 | if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) { | |
1751e8a6 | 604 | if (sb->s_flags & SB_SYNCHRONOUS) { |
1da177e4 LT |
605 | err = fat_sync_bhs(bhs, nr_bhs); |
606 | if (err) | |
607 | goto error; | |
608 | } | |
609 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
610 | if (err) | |
611 | goto error; | |
612 | for (i = 0; i < nr_bhs; i++) | |
613 | brelse(bhs[i]); | |
614 | nr_bhs = 0; | |
615 | } | |
616 | fat_collect_bhs(bhs, &nr_bhs, &fatent); | |
617 | } while (cluster != FAT_ENT_EOF); | |
618 | ||
1751e8a6 | 619 | if (sb->s_flags & SB_SYNCHRONOUS) { |
1da177e4 LT |
620 | err = fat_sync_bhs(bhs, nr_bhs); |
621 | if (err) | |
622 | goto error; | |
623 | } | |
624 | err = fat_mirror_bhs(sb, bhs, nr_bhs); | |
625 | error: | |
626 | fatent_brelse(&fatent); | |
627 | for (i = 0; i < nr_bhs; i++) | |
628 | brelse(bhs[i]); | |
629 | unlock_fat(sbi); | |
330fe3c4 AB |
630 | if (dirty_fsinfo) |
631 | mark_fsinfo_dirty(sb); | |
1da177e4 | 632 | |
1da177e4 LT |
633 | return err; |
634 | } | |
7c709d00 | 635 | EXPORT_SYMBOL_GPL(fat_free_clusters); |
1da177e4 | 636 | |
89831003 OH |
637 | struct fatent_ra { |
638 | sector_t cur; | |
639 | sector_t limit; | |
640 | ||
641 | unsigned int ra_blocks; | |
642 | sector_t ra_advance; | |
643 | sector_t ra_next; | |
644 | sector_t ra_limit; | |
645 | }; | |
9f966be8 | 646 | |
89831003 OH |
647 | static void fat_ra_init(struct super_block *sb, struct fatent_ra *ra, |
648 | struct fat_entry *fatent, int ent_limit) | |
9f966be8 | 649 | { |
89831003 OH |
650 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
651 | const struct fatent_operations *ops = sbi->fatent_ops; | |
652 | sector_t blocknr, block_end; | |
653 | int offset; | |
654 | /* | |
655 | * This is the sequential read, so ra_pages * 2 (but try to | |
656 | * align the optimal hardware IO size). | |
657 | * [BTW, 128kb covers the whole sectors for FAT12 and FAT16] | |
658 | */ | |
659 | unsigned long ra_pages = sb->s_bdi->ra_pages; | |
660 | unsigned int reada_blocks; | |
9f966be8 | 661 | |
a090a5a7 OH |
662 | if (fatent->entry >= ent_limit) |
663 | return; | |
664 | ||
89831003 OH |
665 | if (ra_pages > sb->s_bdi->io_pages) |
666 | ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages); | |
667 | reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1); | |
668 | ||
669 | /* Initialize the range for sequential read */ | |
9f966be8 | 670 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); |
89831003 OH |
671 | ops->ent_blocknr(sb, ent_limit - 1, &offset, &block_end); |
672 | ra->cur = 0; | |
673 | ra->limit = (block_end + 1) - blocknr; | |
9f966be8 | 674 | |
89831003 OH |
675 | /* Advancing the window at half size */ |
676 | ra->ra_blocks = reada_blocks >> 1; | |
677 | ra->ra_advance = ra->cur; | |
678 | ra->ra_next = ra->cur; | |
679 | ra->ra_limit = ra->cur + min_t(sector_t, reada_blocks, ra->limit); | |
680 | } | |
681 | ||
682 | /* Assuming to be called before reading a new block (increments ->cur). */ | |
683 | static void fat_ent_reada(struct super_block *sb, struct fatent_ra *ra, | |
684 | struct fat_entry *fatent) | |
685 | { | |
686 | if (ra->ra_next >= ra->ra_limit) | |
687 | return; | |
688 | ||
689 | if (ra->cur >= ra->ra_advance) { | |
690 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
691 | const struct fatent_operations *ops = sbi->fatent_ops; | |
692 | struct blk_plug plug; | |
693 | sector_t blocknr, diff; | |
694 | int offset; | |
695 | ||
696 | ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); | |
697 | ||
698 | diff = blocknr - ra->cur; | |
699 | blk_start_plug(&plug); | |
700 | /* | |
701 | * FIXME: we would want to directly use the bio with | |
702 | * pages to reduce the number of segments. | |
703 | */ | |
704 | for (; ra->ra_next < ra->ra_limit; ra->ra_next++) | |
705 | sb_breadahead(sb, ra->ra_next + diff); | |
706 | blk_finish_plug(&plug); | |
707 | ||
708 | /* Advance the readahead window */ | |
709 | ra->ra_advance += ra->ra_blocks; | |
710 | ra->ra_limit += min_t(sector_t, | |
711 | ra->ra_blocks, ra->limit - ra->ra_limit); | |
712 | } | |
713 | ra->cur++; | |
9f966be8 OH |
714 | } |
715 | ||
1da177e4 LT |
716 | int fat_count_free_clusters(struct super_block *sb) |
717 | { | |
718 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
8992de4c | 719 | const struct fatent_operations *ops = sbi->fatent_ops; |
1da177e4 | 720 | struct fat_entry fatent; |
89831003 | 721 | struct fatent_ra fatent_ra; |
1da177e4 LT |
722 | int err = 0, free; |
723 | ||
724 | lock_fat(sbi); | |
606e423e | 725 | if (sbi->free_clusters != -1 && sbi->free_clus_valid) |
1da177e4 LT |
726 | goto out; |
727 | ||
728 | free = 0; | |
729 | fatent_init(&fatent); | |
730 | fatent_set_entry(&fatent, FAT_START_ENT); | |
89831003 | 731 | fat_ra_init(sb, &fatent_ra, &fatent, sbi->max_cluster); |
1da177e4 | 732 | while (fatent.entry < sbi->max_cluster) { |
9f966be8 | 733 | /* readahead of fat blocks */ |
89831003 | 734 | fat_ent_reada(sb, &fatent_ra, &fatent); |
9f966be8 | 735 | |
1da177e4 LT |
736 | err = fat_ent_read_block(sb, &fatent); |
737 | if (err) | |
738 | goto out; | |
739 | ||
740 | do { | |
741 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) | |
742 | free++; | |
743 | } while (fat_ent_next(sbi, &fatent)); | |
ac081c3b | 744 | cond_resched(); |
1da177e4 LT |
745 | } |
746 | sbi->free_clusters = free; | |
606e423e | 747 | sbi->free_clus_valid = 1; |
90b43665 | 748 | mark_fsinfo_dirty(sb); |
1da177e4 LT |
749 | fatent_brelse(&fatent); |
750 | out: | |
751 | unlock_fat(sbi); | |
752 | return err; | |
753 | } | |
f663b5b3 WW |
754 | |
755 | static int fat_trim_clusters(struct super_block *sb, u32 clus, u32 nr_clus) | |
756 | { | |
757 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
758 | return sb_issue_discard(sb, fat_clus_to_blknr(sbi, clus), | |
759 | nr_clus * sbi->sec_per_clus, GFP_NOFS, 0); | |
760 | } | |
761 | ||
762 | int fat_trim_fs(struct inode *inode, struct fstrim_range *range) | |
763 | { | |
764 | struct super_block *sb = inode->i_sb; | |
765 | struct msdos_sb_info *sbi = MSDOS_SB(sb); | |
766 | const struct fatent_operations *ops = sbi->fatent_ops; | |
767 | struct fat_entry fatent; | |
89831003 | 768 | struct fatent_ra fatent_ra; |
f663b5b3 WW |
769 | u64 ent_start, ent_end, minlen, trimmed = 0; |
770 | u32 free = 0; | |
f663b5b3 WW |
771 | int err = 0; |
772 | ||
773 | /* | |
774 | * FAT data is organized as clusters, trim at the granulary of cluster. | |
775 | * | |
a109ae2a | 776 | * fstrim_range is in byte, convert values to cluster index. |
f663b5b3 WW |
777 | * Treat sectors before data region as all used, not to trim them. |
778 | */ | |
779 | ent_start = max_t(u64, range->start>>sbi->cluster_bits, FAT_START_ENT); | |
780 | ent_end = ent_start + (range->len >> sbi->cluster_bits) - 1; | |
781 | minlen = range->minlen >> sbi->cluster_bits; | |
782 | ||
783 | if (ent_start >= sbi->max_cluster || range->len < sbi->cluster_size) | |
784 | return -EINVAL; | |
785 | if (ent_end >= sbi->max_cluster) | |
786 | ent_end = sbi->max_cluster - 1; | |
787 | ||
f663b5b3 WW |
788 | fatent_init(&fatent); |
789 | lock_fat(sbi); | |
790 | fatent_set_entry(&fatent, ent_start); | |
89831003 | 791 | fat_ra_init(sb, &fatent_ra, &fatent, ent_end + 1); |
f663b5b3 WW |
792 | while (fatent.entry <= ent_end) { |
793 | /* readahead of fat blocks */ | |
89831003 | 794 | fat_ent_reada(sb, &fatent_ra, &fatent); |
f663b5b3 WW |
795 | |
796 | err = fat_ent_read_block(sb, &fatent); | |
797 | if (err) | |
798 | goto error; | |
799 | do { | |
800 | if (ops->ent_get(&fatent) == FAT_ENT_FREE) { | |
801 | free++; | |
802 | } else if (free) { | |
803 | if (free >= minlen) { | |
804 | u32 clus = fatent.entry - free; | |
805 | ||
806 | err = fat_trim_clusters(sb, clus, free); | |
807 | if (err && err != -EOPNOTSUPP) | |
808 | goto error; | |
809 | if (!err) | |
810 | trimmed += free; | |
811 | err = 0; | |
812 | } | |
813 | free = 0; | |
814 | } | |
815 | } while (fat_ent_next(sbi, &fatent) && fatent.entry <= ent_end); | |
816 | ||
817 | if (fatal_signal_pending(current)) { | |
818 | err = -ERESTARTSYS; | |
819 | goto error; | |
820 | } | |
821 | ||
822 | if (need_resched()) { | |
823 | fatent_brelse(&fatent); | |
824 | unlock_fat(sbi); | |
825 | cond_resched(); | |
826 | lock_fat(sbi); | |
827 | } | |
828 | } | |
829 | /* handle scenario when tail entries are all free */ | |
830 | if (free && free >= minlen) { | |
831 | u32 clus = fatent.entry - free; | |
832 | ||
833 | err = fat_trim_clusters(sb, clus, free); | |
834 | if (err && err != -EOPNOTSUPP) | |
835 | goto error; | |
836 | if (!err) | |
837 | trimmed += free; | |
838 | err = 0; | |
839 | } | |
840 | ||
841 | error: | |
842 | fatent_brelse(&fatent); | |
843 | unlock_fat(sbi); | |
844 | ||
845 | range->len = trimmed << sbi->cluster_bits; | |
846 | ||
847 | return err; | |
848 | } |