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