1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4 */
5
6 #include <linux/slab.h>
7 #include <asm/unaligned.h>
8 #include <linux/buffer_head.h>
9
10 #include "exfat_raw.h"
11 #include "exfat_fs.h"
12
exfat_mirror_bh(struct super_block * sb,sector_t sec,struct buffer_head * bh)13 static int exfat_mirror_bh(struct super_block *sb, sector_t sec,
14 struct buffer_head *bh)
15 {
16 struct buffer_head *c_bh;
17 struct exfat_sb_info *sbi = EXFAT_SB(sb);
18 sector_t sec2;
19 int err = 0;
20
21 if (sbi->FAT2_start_sector != sbi->FAT1_start_sector) {
22 sec2 = sec - sbi->FAT1_start_sector + sbi->FAT2_start_sector;
23 c_bh = sb_getblk(sb, sec2);
24 if (!c_bh)
25 return -ENOMEM;
26 memcpy(c_bh->b_data, bh->b_data, sb->s_blocksize);
27 set_buffer_uptodate(c_bh);
28 mark_buffer_dirty(c_bh);
29 if (sb->s_flags & SB_SYNCHRONOUS)
30 err = sync_dirty_buffer(c_bh);
31 brelse(c_bh);
32 }
33
34 return err;
35 }
36
__exfat_ent_get(struct super_block * sb,unsigned int loc,unsigned int * content)37 static int __exfat_ent_get(struct super_block *sb, unsigned int loc,
38 unsigned int *content)
39 {
40 unsigned int off;
41 sector_t sec;
42 struct buffer_head *bh;
43
44 sec = FAT_ENT_OFFSET_SECTOR(sb, loc);
45 off = FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc);
46
47 bh = sb_bread(sb, sec);
48 if (!bh)
49 return -EIO;
50
51 *content = le32_to_cpu(*(__le32 *)(&bh->b_data[off]));
52
53 /* remap reserved clusters to simplify code */
54 if (*content > EXFAT_BAD_CLUSTER)
55 *content = EXFAT_EOF_CLUSTER;
56
57 brelse(bh);
58 return 0;
59 }
60
exfat_ent_set(struct super_block * sb,unsigned int loc,unsigned int content)61 int exfat_ent_set(struct super_block *sb, unsigned int loc,
62 unsigned int content)
63 {
64 unsigned int off;
65 sector_t sec;
66 __le32 *fat_entry;
67 struct buffer_head *bh;
68
69 sec = FAT_ENT_OFFSET_SECTOR(sb, loc);
70 off = FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc);
71
72 bh = sb_bread(sb, sec);
73 if (!bh)
74 return -EIO;
75
76 fat_entry = (__le32 *)&(bh->b_data[off]);
77 *fat_entry = cpu_to_le32(content);
78 exfat_update_bh(bh, sb->s_flags & SB_SYNCHRONOUS);
79 exfat_mirror_bh(sb, sec, bh);
80 brelse(bh);
81 return 0;
82 }
83
is_valid_cluster(struct exfat_sb_info * sbi,unsigned int clus)84 static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
85 unsigned int clus)
86 {
87 if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus)
88 return false;
89 return true;
90 }
91
exfat_ent_get(struct super_block * sb,unsigned int loc,unsigned int * content)92 int exfat_ent_get(struct super_block *sb, unsigned int loc,
93 unsigned int *content)
94 {
95 struct exfat_sb_info *sbi = EXFAT_SB(sb);
96 int err;
97
98 if (!is_valid_cluster(sbi, loc)) {
99 exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)",
100 loc);
101 return -EIO;
102 }
103
104 err = __exfat_ent_get(sb, loc, content);
105 if (err) {
106 exfat_fs_error(sb,
107 "failed to access to FAT (entry 0x%08x, err:%d)",
108 loc, err);
109 return err;
110 }
111
112 if (*content == EXFAT_FREE_CLUSTER) {
113 exfat_fs_error(sb,
114 "invalid access to FAT free cluster (entry 0x%08x)",
115 loc);
116 return -EIO;
117 }
118
119 if (*content == EXFAT_BAD_CLUSTER) {
120 exfat_fs_error(sb,
121 "invalid access to FAT bad cluster (entry 0x%08x)",
122 loc);
123 return -EIO;
124 }
125
126 if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) {
127 exfat_fs_error(sb,
128 "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)",
129 loc, *content);
130 return -EIO;
131 }
132
133 return 0;
134 }
135
exfat_chain_cont_cluster(struct super_block * sb,unsigned int chain,unsigned int len)136 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
137 unsigned int len)
138 {
139 if (!len)
140 return 0;
141
142 while (len > 1) {
143 if (exfat_ent_set(sb, chain, chain + 1))
144 return -EIO;
145 chain++;
146 len--;
147 }
148
149 if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER))
150 return -EIO;
151 return 0;
152 }
153
154 /* This function must be called with bitmap_lock held */
__exfat_free_cluster(struct inode * inode,struct exfat_chain * p_chain)155 static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
156 {
157 struct super_block *sb = inode->i_sb;
158 struct exfat_sb_info *sbi = EXFAT_SB(sb);
159 int cur_cmap_i, next_cmap_i;
160 unsigned int num_clusters = 0;
161 unsigned int clu;
162
163 /* invalid cluster number */
164 if (p_chain->dir == EXFAT_FREE_CLUSTER ||
165 p_chain->dir == EXFAT_EOF_CLUSTER ||
166 p_chain->dir < EXFAT_FIRST_CLUSTER)
167 return 0;
168
169 /* no cluster to truncate */
170 if (p_chain->size == 0)
171 return 0;
172
173 /* check cluster validation */
174 if (!is_valid_cluster(sbi, p_chain->dir)) {
175 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
176 return -EIO;
177 }
178
179 clu = p_chain->dir;
180
181 cur_cmap_i = next_cmap_i =
182 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu));
183
184 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
185 unsigned int last_cluster = p_chain->dir + p_chain->size - 1;
186 do {
187 bool sync = false;
188
189 if (clu < last_cluster)
190 next_cmap_i =
191 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1));
192
193 /* flush bitmap only if index would be changed or for last cluster */
194 if (clu == last_cluster || cur_cmap_i != next_cmap_i) {
195 sync = true;
196 cur_cmap_i = next_cmap_i;
197 }
198
199 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
200 clu++;
201 num_clusters++;
202 } while (num_clusters < p_chain->size);
203 } else {
204 do {
205 bool sync = false;
206 unsigned int n_clu = clu;
207 int err = exfat_get_next_cluster(sb, &n_clu);
208
209 if (err || n_clu == EXFAT_EOF_CLUSTER)
210 sync = true;
211 else
212 next_cmap_i =
213 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu));
214
215 if (cur_cmap_i != next_cmap_i) {
216 sync = true;
217 cur_cmap_i = next_cmap_i;
218 }
219
220 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
221 clu = n_clu;
222 num_clusters++;
223
224 if (err)
225 goto dec_used_clus;
226 } while (clu != EXFAT_EOF_CLUSTER);
227 }
228
229 dec_used_clus:
230 sbi->used_clusters -= num_clusters;
231 return 0;
232 }
233
exfat_free_cluster(struct inode * inode,struct exfat_chain * p_chain)234 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
235 {
236 int ret = 0;
237
238 mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
239 ret = __exfat_free_cluster(inode, p_chain);
240 mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
241
242 return ret;
243 }
244
exfat_find_last_cluster(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_clu)245 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
246 unsigned int *ret_clu)
247 {
248 unsigned int clu, next;
249 unsigned int count = 0;
250
251 next = p_chain->dir;
252 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
253 *ret_clu = next + p_chain->size - 1;
254 return 0;
255 }
256
257 do {
258 count++;
259 clu = next;
260 if (exfat_ent_get(sb, clu, &next))
261 return -EIO;
262 } while (next != EXFAT_EOF_CLUSTER);
263
264 if (p_chain->size != count) {
265 exfat_fs_error(sb,
266 "bogus directory size (clus : ondisk(%d) != counted(%d))",
267 p_chain->size, count);
268 return -EIO;
269 }
270
271 *ret_clu = clu;
272 return 0;
273 }
274
exfat_zeroed_cluster(struct inode * dir,unsigned int clu)275 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
276 {
277 struct super_block *sb = dir->i_sb;
278 struct exfat_sb_info *sbi = EXFAT_SB(sb);
279 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
280 int nr_bhs = MAX_BUF_PER_PAGE;
281 sector_t blknr, last_blknr;
282 int err, i, n;
283
284 blknr = exfat_cluster_to_sector(sbi, clu);
285 last_blknr = blknr + sbi->sect_per_clus;
286
287 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
288 exfat_fs_error_ratelimit(sb,
289 "%s: out of range(sect:%llu len:%u)",
290 __func__, (unsigned long long)blknr,
291 sbi->sect_per_clus);
292 return -EIO;
293 }
294
295 /* Zeroing the unused blocks on this cluster */
296 while (blknr < last_blknr) {
297 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) {
298 bhs[n] = sb_getblk(sb, blknr);
299 if (!bhs[n]) {
300 err = -ENOMEM;
301 goto release_bhs;
302 }
303 memset(bhs[n]->b_data, 0, sb->s_blocksize);
304 }
305
306 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
307 if (err)
308 goto release_bhs;
309
310 for (i = 0; i < n; i++)
311 brelse(bhs[i]);
312 }
313 return 0;
314
315 release_bhs:
316 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
317 for (i = 0; i < n; i++)
318 bforget(bhs[i]);
319 return err;
320 }
321
exfat_alloc_cluster(struct inode * inode,unsigned int num_alloc,struct exfat_chain * p_chain,bool sync_bmap)322 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
323 struct exfat_chain *p_chain, bool sync_bmap)
324 {
325 int ret = -ENOSPC;
326 unsigned int num_clusters = 0, total_cnt;
327 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
328 struct super_block *sb = inode->i_sb;
329 struct exfat_sb_info *sbi = EXFAT_SB(sb);
330
331 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
332
333 if (unlikely(total_cnt < sbi->used_clusters)) {
334 exfat_fs_error_ratelimit(sb,
335 "%s: invalid used clusters(t:%u,u:%u)\n",
336 __func__, total_cnt, sbi->used_clusters);
337 return -EIO;
338 }
339
340 if (num_alloc > total_cnt - sbi->used_clusters)
341 return -ENOSPC;
342
343 mutex_lock(&sbi->bitmap_lock);
344
345 hint_clu = p_chain->dir;
346 /* find new cluster */
347 if (hint_clu == EXFAT_EOF_CLUSTER) {
348 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
349 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
350 sbi->clu_srch_ptr);
351 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
352 }
353
354 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
355 if (hint_clu == EXFAT_EOF_CLUSTER) {
356 ret = -ENOSPC;
357 goto unlock;
358 }
359 }
360
361 /* check cluster validation */
362 if (!is_valid_cluster(sbi, hint_clu)) {
363 exfat_err(sb, "hint_cluster is invalid (%u)",
364 hint_clu);
365 hint_clu = EXFAT_FIRST_CLUSTER;
366 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
367 if (exfat_chain_cont_cluster(sb, p_chain->dir,
368 num_clusters)) {
369 ret = -EIO;
370 goto unlock;
371 }
372 p_chain->flags = ALLOC_FAT_CHAIN;
373 }
374 }
375
376 p_chain->dir = EXFAT_EOF_CLUSTER;
377
378 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
379 EXFAT_EOF_CLUSTER) {
380 if (new_clu != hint_clu &&
381 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
382 if (exfat_chain_cont_cluster(sb, p_chain->dir,
383 num_clusters)) {
384 ret = -EIO;
385 goto free_cluster;
386 }
387 p_chain->flags = ALLOC_FAT_CHAIN;
388 }
389
390 /* update allocation bitmap */
391 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
392 ret = -EIO;
393 goto free_cluster;
394 }
395
396 num_clusters++;
397
398 /* update FAT table */
399 if (p_chain->flags == ALLOC_FAT_CHAIN) {
400 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
401 ret = -EIO;
402 goto free_cluster;
403 }
404 }
405
406 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
407 p_chain->dir = new_clu;
408 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
409 if (exfat_ent_set(sb, last_clu, new_clu)) {
410 ret = -EIO;
411 goto free_cluster;
412 }
413 }
414 last_clu = new_clu;
415
416 if (--num_alloc == 0) {
417 sbi->clu_srch_ptr = hint_clu;
418 sbi->used_clusters += num_clusters;
419
420 p_chain->size += num_clusters;
421 mutex_unlock(&sbi->bitmap_lock);
422 return 0;
423 }
424
425 hint_clu = new_clu + 1;
426 if (hint_clu >= sbi->num_clusters) {
427 hint_clu = EXFAT_FIRST_CLUSTER;
428
429 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
430 if (exfat_chain_cont_cluster(sb, p_chain->dir,
431 num_clusters)) {
432 ret = -EIO;
433 goto free_cluster;
434 }
435 p_chain->flags = ALLOC_FAT_CHAIN;
436 }
437 }
438 }
439 free_cluster:
440 if (num_clusters)
441 __exfat_free_cluster(inode, p_chain);
442 unlock:
443 mutex_unlock(&sbi->bitmap_lock);
444 return ret;
445 }
446
exfat_count_num_clusters(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_count)447 int exfat_count_num_clusters(struct super_block *sb,
448 struct exfat_chain *p_chain, unsigned int *ret_count)
449 {
450 unsigned int i, count;
451 unsigned int clu;
452 struct exfat_sb_info *sbi = EXFAT_SB(sb);
453
454 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
455 *ret_count = 0;
456 return 0;
457 }
458
459 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
460 *ret_count = p_chain->size;
461 return 0;
462 }
463
464 clu = p_chain->dir;
465 count = 0;
466 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
467 count++;
468 if (exfat_ent_get(sb, clu, &clu))
469 return -EIO;
470 if (clu == EXFAT_EOF_CLUSTER)
471 break;
472 }
473
474 *ret_count = count;
475 return 0;
476 }
477