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
exfat_ent_get(struct super_block * sb,unsigned int loc,unsigned int * content)84 int exfat_ent_get(struct super_block *sb, unsigned int loc,
85 unsigned int *content)
86 {
87 struct exfat_sb_info *sbi = EXFAT_SB(sb);
88 int err;
89
90 if (!is_valid_cluster(sbi, loc)) {
91 exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)",
92 loc);
93 return -EIO;
94 }
95
96 err = __exfat_ent_get(sb, loc, content);
97 if (err) {
98 exfat_fs_error(sb,
99 "failed to access to FAT (entry 0x%08x, err:%d)",
100 loc, err);
101 return err;
102 }
103
104 if (*content == EXFAT_FREE_CLUSTER) {
105 exfat_fs_error(sb,
106 "invalid access to FAT free cluster (entry 0x%08x)",
107 loc);
108 return -EIO;
109 }
110
111 if (*content == EXFAT_BAD_CLUSTER) {
112 exfat_fs_error(sb,
113 "invalid access to FAT bad cluster (entry 0x%08x)",
114 loc);
115 return -EIO;
116 }
117
118 if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) {
119 exfat_fs_error(sb,
120 "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)",
121 loc, *content);
122 return -EIO;
123 }
124
125 return 0;
126 }
127
exfat_chain_cont_cluster(struct super_block * sb,unsigned int chain,unsigned int len)128 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
129 unsigned int len)
130 {
131 if (!len)
132 return 0;
133
134 while (len > 1) {
135 if (exfat_ent_set(sb, chain, chain + 1))
136 return -EIO;
137 chain++;
138 len--;
139 }
140
141 if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER))
142 return -EIO;
143 return 0;
144 }
145
exfat_free_cluster(struct inode * inode,struct exfat_chain * p_chain)146 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
147 {
148 unsigned int num_clusters = 0;
149 unsigned int clu;
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
154 /* invalid cluster number */
155 if (p_chain->dir == EXFAT_FREE_CLUSTER ||
156 p_chain->dir == EXFAT_EOF_CLUSTER ||
157 p_chain->dir < EXFAT_FIRST_CLUSTER)
158 return 0;
159
160 /* no cluster to truncate */
161 if (p_chain->size == 0)
162 return 0;
163
164 /* check cluster validation */
165 if (!is_valid_cluster(sbi, p_chain->dir)) {
166 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
167 return -EIO;
168 }
169
170 clu = p_chain->dir;
171
172 cur_cmap_i = next_cmap_i =
173 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu));
174
175 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
176 unsigned int last_cluster = p_chain->dir + p_chain->size - 1;
177
178 do {
179 bool sync = false;
180
181 if (clu < last_cluster)
182 next_cmap_i =
183 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1));
184
185 /* flush bitmap only if index would be changed or for last cluster */
186 if (clu == last_cluster || cur_cmap_i != next_cmap_i) {
187 sync = true;
188 cur_cmap_i = next_cmap_i;
189 }
190
191 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
192 clu++;
193 num_clusters++;
194 } while (num_clusters < p_chain->size);
195 } else {
196 do {
197 bool sync = false;
198 unsigned int n_clu = clu;
199 int err = exfat_get_next_cluster(sb, &n_clu);
200
201 if (err || n_clu == EXFAT_EOF_CLUSTER)
202 sync = true;
203 else
204 next_cmap_i =
205 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu));
206
207 if (cur_cmap_i != next_cmap_i) {
208 sync = true;
209 cur_cmap_i = next_cmap_i;
210 }
211
212 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
213 clu = n_clu;
214
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
exfat_find_last_cluster(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_clu)227 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
228 unsigned int *ret_clu)
229 {
230 unsigned int clu, next;
231 unsigned int count = 0;
232
233 next = p_chain->dir;
234 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
235 *ret_clu = next + p_chain->size - 1;
236 return 0;
237 }
238
239 do {
240 count++;
241 clu = next;
242 if (exfat_ent_get(sb, clu, &next))
243 return -EIO;
244 } while (next != EXFAT_EOF_CLUSTER);
245
246 if (p_chain->size != count) {
247 exfat_fs_error(sb,
248 "bogus directory size (clus : ondisk(%d) != counted(%d))",
249 p_chain->size, count);
250 return -EIO;
251 }
252
253 *ret_clu = clu;
254 return 0;
255 }
256
exfat_zeroed_cluster(struct inode * dir,unsigned int clu)257 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
258 {
259 struct super_block *sb = dir->i_sb;
260 struct exfat_sb_info *sbi = EXFAT_SB(sb);
261 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
262 int nr_bhs = MAX_BUF_PER_PAGE;
263 sector_t blknr, last_blknr;
264 int err, i, n;
265
266 blknr = exfat_cluster_to_sector(sbi, clu);
267 last_blknr = blknr + sbi->sect_per_clus;
268
269 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
270 exfat_fs_error_ratelimit(sb,
271 "%s: out of range(sect:%llu len:%u)",
272 __func__, (unsigned long long)blknr,
273 sbi->sect_per_clus);
274 return -EIO;
275 }
276
277 /* Zeroing the unused blocks on this cluster */
278 while (blknr < last_blknr) {
279 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) {
280 bhs[n] = sb_getblk(sb, blknr);
281 if (!bhs[n]) {
282 err = -ENOMEM;
283 goto release_bhs;
284 }
285 memset(bhs[n]->b_data, 0, sb->s_blocksize);
286 }
287
288 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
289 if (err)
290 goto release_bhs;
291
292 for (i = 0; i < n; i++)
293 brelse(bhs[i]);
294 }
295 return 0;
296
297 release_bhs:
298 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
299 for (i = 0; i < n; i++)
300 bforget(bhs[i]);
301 return err;
302 }
303
exfat_alloc_cluster(struct inode * inode,unsigned int num_alloc,struct exfat_chain * p_chain,bool sync_bmap)304 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
305 struct exfat_chain *p_chain, bool sync_bmap)
306 {
307 int ret = -ENOSPC;
308 unsigned int num_clusters = 0, total_cnt;
309 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
310 struct super_block *sb = inode->i_sb;
311 struct exfat_sb_info *sbi = EXFAT_SB(sb);
312
313 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
314
315 if (unlikely(total_cnt < sbi->used_clusters)) {
316 exfat_fs_error_ratelimit(sb,
317 "%s: invalid used clusters(t:%u,u:%u)\n",
318 __func__, total_cnt, sbi->used_clusters);
319 return -EIO;
320 }
321
322 if (num_alloc > total_cnt - sbi->used_clusters)
323 return -ENOSPC;
324
325 hint_clu = p_chain->dir;
326 /* find new cluster */
327 if (hint_clu == EXFAT_EOF_CLUSTER) {
328 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
329 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
330 sbi->clu_srch_ptr);
331 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
332 }
333
334 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
335 if (hint_clu == EXFAT_EOF_CLUSTER)
336 return -ENOSPC;
337 }
338
339 /* check cluster validation */
340 if (!is_valid_cluster(sbi, hint_clu)) {
341 exfat_err(sb, "hint_cluster is invalid (%u)",
342 hint_clu);
343 hint_clu = EXFAT_FIRST_CLUSTER;
344 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
345 if (exfat_chain_cont_cluster(sb, p_chain->dir,
346 num_clusters))
347 return -EIO;
348 p_chain->flags = ALLOC_FAT_CHAIN;
349 }
350 }
351
352 p_chain->dir = EXFAT_EOF_CLUSTER;
353
354 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
355 EXFAT_EOF_CLUSTER) {
356 if (new_clu != hint_clu &&
357 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
358 if (exfat_chain_cont_cluster(sb, p_chain->dir,
359 num_clusters)) {
360 ret = -EIO;
361 goto free_cluster;
362 }
363 p_chain->flags = ALLOC_FAT_CHAIN;
364 }
365
366 /* update allocation bitmap */
367 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
368 ret = -EIO;
369 goto free_cluster;
370 }
371
372 num_clusters++;
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 last_clu = new_clu;
391
392 if (--num_alloc == 0) {
393 sbi->clu_srch_ptr = hint_clu;
394 sbi->used_clusters += num_clusters;
395
396 p_chain->size += num_clusters;
397 return 0;
398 }
399
400 hint_clu = new_clu + 1;
401 if (hint_clu >= sbi->num_clusters) {
402 hint_clu = EXFAT_FIRST_CLUSTER;
403
404 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
405 if (exfat_chain_cont_cluster(sb, p_chain->dir,
406 num_clusters)) {
407 ret = -EIO;
408 goto free_cluster;
409 }
410 p_chain->flags = ALLOC_FAT_CHAIN;
411 }
412 }
413 }
414 free_cluster:
415 if (num_clusters)
416 exfat_free_cluster(inode, p_chain);
417 return ret;
418 }
419
exfat_count_num_clusters(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_count)420 int exfat_count_num_clusters(struct super_block *sb,
421 struct exfat_chain *p_chain, unsigned int *ret_count)
422 {
423 unsigned int i, count;
424 unsigned int clu;
425 struct exfat_sb_info *sbi = EXFAT_SB(sb);
426
427 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
428 *ret_count = 0;
429 return 0;
430 }
431
432 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
433 *ret_count = p_chain->size;
434 return 0;
435 }
436
437 clu = p_chain->dir;
438 count = 0;
439 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
440 count++;
441 if (exfat_ent_get(sb, clu, &clu))
442 return -EIO;
443 if (clu == EXFAT_EOF_CLUSTER)
444 break;
445 }
446
447 *ret_count = count;
448 return 0;
449 }
450