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 #include <linux/blkdev.h>
10
11 #include "exfat_raw.h"
12 #include "exfat_fs.h"
13
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
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
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
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
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 */
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 } while (clu != EXFAT_EOF_CLUSTER);
220 }
221
222 dec_used_clus:
223 sbi->used_clusters -= num_clusters;
224 return 0;
225 }
226
227 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
228 {
229 int ret = 0;
230
231 mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
232 ret = __exfat_free_cluster(inode, p_chain);
233 mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
234
235 return ret;
236 }
237
238 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
239 unsigned int *ret_clu)
240 {
241 unsigned int clu, next;
242 unsigned int count = 0;
243
244 next = p_chain->dir;
245 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
246 *ret_clu = next + p_chain->size - 1;
247 return 0;
248 }
249
250 do {
251 count++;
252 clu = next;
253 if (exfat_ent_get(sb, clu, &next))
254 return -EIO;
255 } while (next != EXFAT_EOF_CLUSTER);
256
257 if (p_chain->size != count) {
258 exfat_fs_error(sb,
259 "bogus directory size (clus : ondisk(%d) != counted(%d))",
260 p_chain->size, count);
261 return -EIO;
262 }
263
264 *ret_clu = clu;
265 return 0;
266 }
267
268 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
269 {
270 struct super_block *sb = dir->i_sb;
271 struct exfat_sb_info *sbi = EXFAT_SB(sb);
272 struct buffer_head *bh;
273 sector_t blknr, last_blknr, i;
274
275 blknr = exfat_cluster_to_sector(sbi, clu);
276 last_blknr = blknr + sbi->sect_per_clus;
277
278 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
279 exfat_fs_error_ratelimit(sb,
280 "%s: out of range(sect:%llu len:%u)",
281 __func__, (unsigned long long)blknr,
282 sbi->sect_per_clus);
283 return -EIO;
284 }
285
286 /* Zeroing the unused blocks on this cluster */
287 for (i = blknr; i < last_blknr; i++) {
288 bh = sb_getblk(sb, i);
289 if (!bh)
290 return -ENOMEM;
291
292 memset(bh->b_data, 0, sb->s_blocksize);
293 set_buffer_uptodate(bh);
294 mark_buffer_dirty(bh);
295 brelse(bh);
296 }
297
298 if (IS_DIRSYNC(dir))
299 return sync_blockdev_range(sb->s_bdev,
300 EXFAT_BLK_TO_B(blknr, sb),
301 EXFAT_BLK_TO_B(last_blknr, sb) - 1);
302
303 return 0;
304 }
305
306 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
307 struct exfat_chain *p_chain, bool sync_bmap)
308 {
309 int ret = -ENOSPC;
310 unsigned int total_cnt;
311 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
312 struct super_block *sb = inode->i_sb;
313 struct exfat_sb_info *sbi = EXFAT_SB(sb);
314
315 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
316
317 if (unlikely(total_cnt < sbi->used_clusters)) {
318 exfat_fs_error_ratelimit(sb,
319 "%s: invalid used clusters(t:%u,u:%u)\n",
320 __func__, total_cnt, sbi->used_clusters);
321 return -EIO;
322 }
323
324 if (num_alloc > total_cnt - sbi->used_clusters)
325 return -ENOSPC;
326
327 mutex_lock(&sbi->bitmap_lock);
328
329 hint_clu = p_chain->dir;
330 /* find new cluster */
331 if (hint_clu == EXFAT_EOF_CLUSTER) {
332 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
333 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)",
334 sbi->clu_srch_ptr);
335 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
336 }
337
338 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
339 if (hint_clu == EXFAT_EOF_CLUSTER) {
340 ret = -ENOSPC;
341 goto unlock;
342 }
343 }
344
345 /* check cluster validation */
346 if (!is_valid_cluster(sbi, hint_clu)) {
347 if (hint_clu != sbi->num_clusters)
348 exfat_err(sb, "hint_cluster is invalid (%u), rewind to the first cluster",
349 hint_clu);
350 hint_clu = EXFAT_FIRST_CLUSTER;
351 p_chain->flags = ALLOC_FAT_CHAIN;
352 }
353
354 p_chain->dir = EXFAT_EOF_CLUSTER;
355
356 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
357 EXFAT_EOF_CLUSTER) {
358 if (new_clu != hint_clu &&
359 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
360 if (exfat_chain_cont_cluster(sb, p_chain->dir,
361 p_chain->size)) {
362 ret = -EIO;
363 goto free_cluster;
364 }
365 p_chain->flags = ALLOC_FAT_CHAIN;
366 }
367
368 /* update allocation bitmap */
369 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
370 ret = -EIO;
371 goto free_cluster;
372 }
373
374 /* update FAT table */
375 if (p_chain->flags == ALLOC_FAT_CHAIN) {
376 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
377 ret = -EIO;
378 goto free_cluster;
379 }
380 }
381
382 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
383 p_chain->dir = new_clu;
384 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
385 if (exfat_ent_set(sb, last_clu, new_clu)) {
386 ret = -EIO;
387 goto free_cluster;
388 }
389 }
390 p_chain->size++;
391
392 last_clu = new_clu;
393
394 if (p_chain->size == num_alloc) {
395 sbi->clu_srch_ptr = hint_clu;
396 sbi->used_clusters += num_alloc;
397
398 mutex_unlock(&sbi->bitmap_lock);
399 return 0;
400 }
401
402 hint_clu = new_clu + 1;
403 if (hint_clu >= sbi->num_clusters) {
404 hint_clu = EXFAT_FIRST_CLUSTER;
405
406 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
407 if (exfat_chain_cont_cluster(sb, p_chain->dir,
408 p_chain->size)) {
409 ret = -EIO;
410 goto free_cluster;
411 }
412 p_chain->flags = ALLOC_FAT_CHAIN;
413 }
414 }
415 }
416 free_cluster:
417 __exfat_free_cluster(inode, p_chain);
418 unlock:
419 mutex_unlock(&sbi->bitmap_lock);
420 return ret;
421 }
422
423 int exfat_count_num_clusters(struct super_block *sb,
424 struct exfat_chain *p_chain, unsigned int *ret_count)
425 {
426 unsigned int i, count;
427 unsigned int clu;
428 struct exfat_sb_info *sbi = EXFAT_SB(sb);
429
430 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
431 *ret_count = 0;
432 return 0;
433 }
434
435 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
436 *ret_count = p_chain->size;
437 return 0;
438 }
439
440 clu = p_chain->dir;
441 count = 0;
442 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
443 count++;
444 if (exfat_ent_get(sb, clu, &clu))
445 return -EIO;
446 if (clu == EXFAT_EOF_CLUSTER)
447 break;
448 }
449
450 *ret_count = count;
451 return 0;
452 }
453
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