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
153 /* invalid cluster number */
154 if (p_chain->dir == EXFAT_FREE_CLUSTER ||
155 p_chain->dir == EXFAT_EOF_CLUSTER ||
156 p_chain->dir < EXFAT_FIRST_CLUSTER)
157 return 0;
158
159 /* no cluster to truncate */
160 if (p_chain->size == 0)
161 return 0;
162
163 /* check cluster validation */
164 if (!is_valid_cluster(sbi, p_chain->dir)) {
165 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
166 return -EIO;
167 }
168
169 clu = p_chain->dir;
170
171 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
172 do {
173 exfat_clear_bitmap(inode, clu);
174 clu++;
175
176 num_clusters++;
177 } while (num_clusters < p_chain->size);
178 } else {
179 do {
180 exfat_clear_bitmap(inode, clu);
181
182 if (exfat_get_next_cluster(sb, &clu))
183 goto dec_used_clus;
184
185 num_clusters++;
186 } while (clu != EXFAT_EOF_CLUSTER);
187 }
188
189 dec_used_clus:
190 sbi->used_clusters -= num_clusters;
191 return 0;
192 }
193
exfat_find_last_cluster(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_clu)194 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
195 unsigned int *ret_clu)
196 {
197 unsigned int clu, next;
198 unsigned int count = 0;
199
200 next = p_chain->dir;
201 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
202 *ret_clu = next + p_chain->size - 1;
203 return 0;
204 }
205
206 do {
207 count++;
208 clu = next;
209 if (exfat_ent_get(sb, clu, &next))
210 return -EIO;
211 } while (next != EXFAT_EOF_CLUSTER);
212
213 if (p_chain->size != count) {
214 exfat_fs_error(sb,
215 "bogus directory size (clus : ondisk(%d) != counted(%d))",
216 p_chain->size, count);
217 return -EIO;
218 }
219
220 *ret_clu = clu;
221 return 0;
222 }
223
exfat_zeroed_cluster(struct inode * dir,unsigned int clu)224 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
225 {
226 struct super_block *sb = dir->i_sb;
227 struct exfat_sb_info *sbi = EXFAT_SB(sb);
228 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
229 int nr_bhs = MAX_BUF_PER_PAGE;
230 sector_t blknr, last_blknr;
231 int err, i, n;
232
233 blknr = exfat_cluster_to_sector(sbi, clu);
234 last_blknr = blknr + sbi->sect_per_clus;
235
236 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
237 exfat_fs_error_ratelimit(sb,
238 "%s: out of range(sect:%llu len:%u)",
239 __func__, (unsigned long long)blknr,
240 sbi->sect_per_clus);
241 return -EIO;
242 }
243
244 /* Zeroing the unused blocks on this cluster */
245 while (blknr < last_blknr) {
246 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) {
247 bhs[n] = sb_getblk(sb, blknr);
248 if (!bhs[n]) {
249 err = -ENOMEM;
250 goto release_bhs;
251 }
252 memset(bhs[n]->b_data, 0, sb->s_blocksize);
253 }
254
255 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
256 if (err)
257 goto release_bhs;
258
259 for (i = 0; i < n; i++)
260 brelse(bhs[i]);
261 }
262 return 0;
263
264 release_bhs:
265 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
266 for (i = 0; i < n; i++)
267 bforget(bhs[i]);
268 return err;
269 }
270
exfat_alloc_cluster(struct inode * inode,unsigned int num_alloc,struct exfat_chain * p_chain)271 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
272 struct exfat_chain *p_chain)
273 {
274 int ret = -ENOSPC;
275 unsigned int num_clusters = 0, total_cnt;
276 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
277 struct super_block *sb = inode->i_sb;
278 struct exfat_sb_info *sbi = EXFAT_SB(sb);
279
280 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
281
282 if (unlikely(total_cnt < sbi->used_clusters)) {
283 exfat_fs_error_ratelimit(sb,
284 "%s: invalid used clusters(t:%u,u:%u)\n",
285 __func__, total_cnt, sbi->used_clusters);
286 return -EIO;
287 }
288
289 if (num_alloc > total_cnt - sbi->used_clusters)
290 return -ENOSPC;
291
292 hint_clu = p_chain->dir;
293 /* find new cluster */
294 if (hint_clu == EXFAT_EOF_CLUSTER) {
295 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
296 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
297 sbi->clu_srch_ptr);
298 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
299 }
300
301 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
302 if (hint_clu == EXFAT_EOF_CLUSTER)
303 return -ENOSPC;
304 }
305
306 /* check cluster validation */
307 if (!is_valid_cluster(sbi, hint_clu)) {
308 exfat_err(sb, "hint_cluster is invalid (%u)",
309 hint_clu);
310 hint_clu = EXFAT_FIRST_CLUSTER;
311 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
312 if (exfat_chain_cont_cluster(sb, p_chain->dir,
313 num_clusters))
314 return -EIO;
315 p_chain->flags = ALLOC_FAT_CHAIN;
316 }
317 }
318
319 p_chain->dir = EXFAT_EOF_CLUSTER;
320
321 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
322 EXFAT_EOF_CLUSTER) {
323 if (new_clu != hint_clu &&
324 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
325 if (exfat_chain_cont_cluster(sb, p_chain->dir,
326 num_clusters)) {
327 ret = -EIO;
328 goto free_cluster;
329 }
330 p_chain->flags = ALLOC_FAT_CHAIN;
331 }
332
333 /* update allocation bitmap */
334 if (exfat_set_bitmap(inode, new_clu)) {
335 ret = -EIO;
336 goto free_cluster;
337 }
338
339 num_clusters++;
340
341 /* update FAT table */
342 if (p_chain->flags == ALLOC_FAT_CHAIN) {
343 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
344 ret = -EIO;
345 goto free_cluster;
346 }
347 }
348
349 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
350 p_chain->dir = new_clu;
351 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
352 if (exfat_ent_set(sb, last_clu, new_clu)) {
353 ret = -EIO;
354 goto free_cluster;
355 }
356 }
357 last_clu = new_clu;
358
359 if (--num_alloc == 0) {
360 sbi->clu_srch_ptr = hint_clu;
361 sbi->used_clusters += num_clusters;
362
363 p_chain->size += num_clusters;
364 return 0;
365 }
366
367 hint_clu = new_clu + 1;
368 if (hint_clu >= sbi->num_clusters) {
369 hint_clu = EXFAT_FIRST_CLUSTER;
370
371 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
372 if (exfat_chain_cont_cluster(sb, p_chain->dir,
373 num_clusters)) {
374 ret = -EIO;
375 goto free_cluster;
376 }
377 p_chain->flags = ALLOC_FAT_CHAIN;
378 }
379 }
380 }
381 free_cluster:
382 if (num_clusters)
383 exfat_free_cluster(inode, p_chain);
384 return ret;
385 }
386
exfat_count_num_clusters(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_count)387 int exfat_count_num_clusters(struct super_block *sb,
388 struct exfat_chain *p_chain, unsigned int *ret_count)
389 {
390 unsigned int i, count;
391 unsigned int clu;
392 struct exfat_sb_info *sbi = EXFAT_SB(sb);
393
394 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
395 *ret_count = 0;
396 return 0;
397 }
398
399 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
400 *ret_count = p_chain->size;
401 return 0;
402 }
403
404 clu = p_chain->dir;
405 count = 0;
406 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
407 count++;
408 if (exfat_ent_get(sb, clu, &clu))
409 return -EIO;
410 if (clu == EXFAT_EOF_CLUSTER)
411 break;
412 }
413
414 *ret_count = count;
415 return 0;
416 }
417