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 unsigned int last_cluster = p_chain->dir + p_chain->size - 1;
179 do {
180 bool sync = false;
181
182 if (clu < last_cluster)
183 next_cmap_i =
184 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1));
185
186 /* flush bitmap only if index would be changed or for last cluster */
187 if (clu == last_cluster || cur_cmap_i != next_cmap_i) {
188 sync = true;
189 cur_cmap_i = next_cmap_i;
190 }
191
192 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
193 clu++;
194 num_clusters++;
195 } while (num_clusters < p_chain->size);
196 } else {
197 do {
198 bool sync = false;
199 unsigned int n_clu = clu;
200 int err = exfat_get_next_cluster(sb, &n_clu);
201
202 if (err || n_clu == EXFAT_EOF_CLUSTER)
203 sync = true;
204 else
205 next_cmap_i =
206 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu));
207
208 if (cur_cmap_i != next_cmap_i) {
209 sync = true;
210 cur_cmap_i = next_cmap_i;
211 }
212
213 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
214 clu = n_clu;
215 num_clusters++;
216
217 if (err)
218 goto dec_used_clus;
219
220 if (num_clusters >= sbi->num_clusters - EXFAT_FIRST_CLUSTER) {
221 /*
222 * The cluster chain includes a loop, scan the
223 * bitmap to get the number of used clusters.
224 */
225 exfat_count_used_clusters(sb, &sbi->used_clusters);
226
227 return 0;
228 }
229 } while (clu != EXFAT_EOF_CLUSTER);
230 }
231
232 dec_used_clus:
233 sbi->used_clusters -= num_clusters;
234 return 0;
235 }
236
exfat_free_cluster(struct inode * inode,struct exfat_chain * p_chain)237 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
238 {
239 int ret = 0;
240
241 mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
242 ret = __exfat_free_cluster(inode, p_chain);
243 mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
244
245 return ret;
246 }
247
exfat_find_last_cluster(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_clu)248 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
249 unsigned int *ret_clu)
250 {
251 unsigned int clu, next;
252 unsigned int count = 0;
253
254 next = p_chain->dir;
255 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
256 *ret_clu = next + p_chain->size - 1;
257 return 0;
258 }
259
260 do {
261 count++;
262 clu = next;
263 if (exfat_ent_get(sb, clu, &next))
264 return -EIO;
265 } while (next != EXFAT_EOF_CLUSTER);
266
267 if (p_chain->size != count) {
268 exfat_fs_error(sb,
269 "bogus directory size (clus : ondisk(%d) != counted(%d))",
270 p_chain->size, count);
271 return -EIO;
272 }
273
274 *ret_clu = clu;
275 return 0;
276 }
277
exfat_zeroed_cluster(struct inode * dir,unsigned int clu)278 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
279 {
280 struct super_block *sb = dir->i_sb;
281 struct exfat_sb_info *sbi = EXFAT_SB(sb);
282 struct buffer_head *bh;
283 sector_t blknr, last_blknr, i;
284
285 blknr = exfat_cluster_to_sector(sbi, clu);
286 last_blknr = blknr + sbi->sect_per_clus;
287
288 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
289 exfat_fs_error_ratelimit(sb,
290 "%s: out of range(sect:%llu len:%u)",
291 __func__, (unsigned long long)blknr,
292 sbi->sect_per_clus);
293 return -EIO;
294 }
295
296 /* Zeroing the unused blocks on this cluster */
297 for (i = blknr; i < last_blknr; i++) {
298 bh = sb_getblk(sb, i);
299 if (!bh)
300 return -ENOMEM;
301
302 memset(bh->b_data, 0, sb->s_blocksize);
303 set_buffer_uptodate(bh);
304 mark_buffer_dirty(bh);
305 brelse(bh);
306 }
307
308 if (IS_DIRSYNC(dir))
309 return sync_blockdev_range(sb->s_bdev,
310 EXFAT_BLK_TO_B(blknr, sb),
311 EXFAT_BLK_TO_B(last_blknr, sb) - 1);
312
313 return 0;
314 }
315
exfat_alloc_cluster(struct inode * inode,unsigned int num_alloc,struct exfat_chain * p_chain,bool sync_bmap)316 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
317 struct exfat_chain *p_chain, bool sync_bmap)
318 {
319 int ret = -ENOSPC;
320 unsigned int total_cnt;
321 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
322 struct super_block *sb = inode->i_sb;
323 struct exfat_sb_info *sbi = EXFAT_SB(sb);
324
325 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
326
327 if (unlikely(total_cnt < sbi->used_clusters)) {
328 exfat_fs_error_ratelimit(sb,
329 "%s: invalid used clusters(t:%u,u:%u)\n",
330 __func__, total_cnt, sbi->used_clusters);
331 return -EIO;
332 }
333
334 if (num_alloc > total_cnt - sbi->used_clusters)
335 return -ENOSPC;
336
337 mutex_lock(&sbi->bitmap_lock);
338
339 hint_clu = p_chain->dir;
340 /* find new cluster */
341 if (hint_clu == EXFAT_EOF_CLUSTER) {
342 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
343 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)",
344 sbi->clu_srch_ptr);
345 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
346 }
347
348 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
349 if (hint_clu == EXFAT_EOF_CLUSTER) {
350 ret = -ENOSPC;
351 goto unlock;
352 }
353 }
354
355 /* check cluster validation */
356 if (!is_valid_cluster(sbi, hint_clu)) {
357 if (hint_clu != sbi->num_clusters)
358 exfat_err(sb, "hint_cluster is invalid (%u), rewind to the first cluster",
359 hint_clu);
360 hint_clu = EXFAT_FIRST_CLUSTER;
361 p_chain->flags = ALLOC_FAT_CHAIN;
362 }
363
364 p_chain->dir = EXFAT_EOF_CLUSTER;
365
366 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
367 EXFAT_EOF_CLUSTER) {
368 if (new_clu != hint_clu &&
369 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
370 if (exfat_chain_cont_cluster(sb, p_chain->dir,
371 p_chain->size)) {
372 ret = -EIO;
373 goto free_cluster;
374 }
375 p_chain->flags = ALLOC_FAT_CHAIN;
376 }
377
378 /* update allocation bitmap */
379 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
380 ret = -EIO;
381 goto free_cluster;
382 }
383
384 /* update FAT table */
385 if (p_chain->flags == ALLOC_FAT_CHAIN) {
386 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
387 ret = -EIO;
388 goto free_cluster;
389 }
390 }
391
392 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
393 p_chain->dir = new_clu;
394 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
395 if (exfat_ent_set(sb, last_clu, new_clu)) {
396 ret = -EIO;
397 goto free_cluster;
398 }
399 }
400 p_chain->size++;
401
402 last_clu = new_clu;
403
404 if (p_chain->size == num_alloc) {
405 sbi->clu_srch_ptr = hint_clu;
406 sbi->used_clusters += num_alloc;
407
408 mutex_unlock(&sbi->bitmap_lock);
409 return 0;
410 }
411
412 hint_clu = new_clu + 1;
413 if (hint_clu >= sbi->num_clusters) {
414 hint_clu = EXFAT_FIRST_CLUSTER;
415
416 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
417 if (exfat_chain_cont_cluster(sb, p_chain->dir,
418 p_chain->size)) {
419 ret = -EIO;
420 goto free_cluster;
421 }
422 p_chain->flags = ALLOC_FAT_CHAIN;
423 }
424 }
425 }
426 free_cluster:
427 __exfat_free_cluster(inode, p_chain);
428 unlock:
429 mutex_unlock(&sbi->bitmap_lock);
430 return ret;
431 }
432
exfat_count_num_clusters(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_count)433 int exfat_count_num_clusters(struct super_block *sb,
434 struct exfat_chain *p_chain, unsigned int *ret_count)
435 {
436 unsigned int i, count;
437 unsigned int clu;
438 struct exfat_sb_info *sbi = EXFAT_SB(sb);
439
440 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
441 *ret_count = 0;
442 return 0;
443 }
444
445 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
446 *ret_count = p_chain->size;
447 return 0;
448 }
449
450 clu = p_chain->dir;
451 count = 0;
452 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
453 count++;
454 if (exfat_ent_get(sb, clu, &clu))
455 return -EIO;
456 if (clu == EXFAT_EOF_CLUSTER)
457 break;
458 }
459
460 *ret_count = count;
461 return 0;
462 }
463