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/blk_types.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
exfat_free_cluster(struct inode * inode,struct exfat_chain * p_chain)147 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
148 {
149 unsigned int num_clusters = 0;
150 unsigned int clu;
151 struct super_block *sb = inode->i_sb;
152 struct exfat_sb_info *sbi = EXFAT_SB(sb);
153 int cur_cmap_i, next_cmap_i;
154
155 /* invalid cluster number */
156 if (p_chain->dir == EXFAT_FREE_CLUSTER ||
157 p_chain->dir == EXFAT_EOF_CLUSTER ||
158 p_chain->dir < EXFAT_FIRST_CLUSTER)
159 return 0;
160
161 /* no cluster to truncate */
162 if (p_chain->size == 0)
163 return 0;
164
165 /* check cluster validation */
166 if (!is_valid_cluster(sbi, p_chain->dir)) {
167 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
168 return -EIO;
169 }
170
171 clu = p_chain->dir;
172
173 cur_cmap_i = next_cmap_i =
174 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu));
175
176 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
177 unsigned int last_cluster = p_chain->dir + p_chain->size - 1;
178
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
216 num_clusters++;
217
218 if (err)
219 goto dec_used_clus;
220 } while (clu != EXFAT_EOF_CLUSTER);
221 }
222
223 dec_used_clus:
224 sbi->used_clusters -= num_clusters;
225 return 0;
226 }
227
exfat_find_last_cluster(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_clu)228 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
229 unsigned int *ret_clu)
230 {
231 unsigned int clu, next;
232 unsigned int count = 0;
233
234 next = p_chain->dir;
235 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
236 *ret_clu = next + p_chain->size - 1;
237 return 0;
238 }
239
240 do {
241 count++;
242 clu = next;
243 if (exfat_ent_get(sb, clu, &next))
244 return -EIO;
245 } while (next != EXFAT_EOF_CLUSTER);
246
247 if (p_chain->size != count) {
248 exfat_fs_error(sb,
249 "bogus directory size (clus : ondisk(%d) != counted(%d))",
250 p_chain->size, count);
251 return -EIO;
252 }
253
254 *ret_clu = clu;
255 return 0;
256 }
257
exfat_zeroed_cluster(struct inode * dir,unsigned int clu)258 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
259 {
260 struct super_block *sb = dir->i_sb;
261 struct exfat_sb_info *sbi = EXFAT_SB(sb);
262 struct buffer_head *bh;
263 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
264 sector_t blknr, last_blknr;
265 int i;
266
267 blknr = exfat_cluster_to_sector(sbi, clu);
268 last_blknr = blknr + sbi->sect_per_clus;
269
270 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
271 exfat_fs_error_ratelimit(sb,
272 "%s: out of range(sect:%llu len:%u)",
273 __func__, (unsigned long long)blknr,
274 sbi->sect_per_clus);
275 return -EIO;
276 }
277
278 /* Zeroing the unused blocks on this cluster */
279 for (i = blknr; i < last_blknr; i++) {
280 bh = sb_getblk(sb, i);
281 if (!bh)
282 return -ENOMEM;
283
284 memset(bh->b_data, 0, sb->s_blocksize);
285 set_buffer_uptodate(bh);
286 mark_buffer_dirty(bh);
287 brelse(bh);
288 }
289 if (IS_DIRSYNC(dir))
290 return filemap_write_and_wait_range(mapping,
291 EXFAT_BLK_TO_B(blknr, sb),
292 EXFAT_BLK_TO_B(last_blknr, sb) - 1);
293
294 return 0;
295 }
296
exfat_alloc_cluster(struct inode * inode,unsigned int num_alloc,struct exfat_chain * p_chain,bool sync_bmap)297 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
298 struct exfat_chain *p_chain, bool sync_bmap)
299 {
300 int ret = -ENOSPC;
301 unsigned int num_clusters = 0, total_cnt;
302 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
303 struct super_block *sb = inode->i_sb;
304 struct exfat_sb_info *sbi = EXFAT_SB(sb);
305
306 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
307
308 if (unlikely(total_cnt < sbi->used_clusters)) {
309 exfat_fs_error_ratelimit(sb,
310 "%s: invalid used clusters(t:%u,u:%u)\n",
311 __func__, total_cnt, sbi->used_clusters);
312 return -EIO;
313 }
314
315 if (num_alloc > total_cnt - sbi->used_clusters)
316 return -ENOSPC;
317
318 hint_clu = p_chain->dir;
319 /* find new cluster */
320 if (hint_clu == EXFAT_EOF_CLUSTER) {
321 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
322 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
323 sbi->clu_srch_ptr);
324 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
325 }
326
327 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
328 if (hint_clu == EXFAT_EOF_CLUSTER)
329 return -ENOSPC;
330 }
331
332 /* check cluster validation */
333 if (!is_valid_cluster(sbi, hint_clu)) {
334 exfat_err(sb, "hint_cluster is invalid (%u)",
335 hint_clu);
336 hint_clu = EXFAT_FIRST_CLUSTER;
337 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
338 if (exfat_chain_cont_cluster(sb, p_chain->dir,
339 num_clusters))
340 return -EIO;
341 p_chain->flags = ALLOC_FAT_CHAIN;
342 }
343 }
344
345 p_chain->dir = EXFAT_EOF_CLUSTER;
346
347 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
348 EXFAT_EOF_CLUSTER) {
349 if (new_clu != hint_clu &&
350 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
351 if (exfat_chain_cont_cluster(sb, p_chain->dir,
352 num_clusters)) {
353 ret = -EIO;
354 goto free_cluster;
355 }
356 p_chain->flags = ALLOC_FAT_CHAIN;
357 }
358
359 /* update allocation bitmap */
360 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
361 ret = -EIO;
362 goto free_cluster;
363 }
364
365 num_clusters++;
366
367 /* update FAT table */
368 if (p_chain->flags == ALLOC_FAT_CHAIN) {
369 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
370 ret = -EIO;
371 goto free_cluster;
372 }
373 }
374
375 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
376 p_chain->dir = new_clu;
377 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
378 if (exfat_ent_set(sb, last_clu, new_clu)) {
379 ret = -EIO;
380 goto free_cluster;
381 }
382 }
383 last_clu = new_clu;
384
385 if (--num_alloc == 0) {
386 sbi->clu_srch_ptr = hint_clu;
387 sbi->used_clusters += num_clusters;
388
389 p_chain->size += num_clusters;
390 return 0;
391 }
392
393 hint_clu = new_clu + 1;
394 if (hint_clu >= sbi->num_clusters) {
395 hint_clu = EXFAT_FIRST_CLUSTER;
396
397 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
398 if (exfat_chain_cont_cluster(sb, p_chain->dir,
399 num_clusters)) {
400 ret = -EIO;
401 goto free_cluster;
402 }
403 p_chain->flags = ALLOC_FAT_CHAIN;
404 }
405 }
406 }
407 free_cluster:
408 if (num_clusters)
409 exfat_free_cluster(inode, p_chain);
410 return ret;
411 }
412
exfat_count_num_clusters(struct super_block * sb,struct exfat_chain * p_chain,unsigned int * ret_count)413 int exfat_count_num_clusters(struct super_block *sb,
414 struct exfat_chain *p_chain, unsigned int *ret_count)
415 {
416 unsigned int i, count;
417 unsigned int clu;
418 struct exfat_sb_info *sbi = EXFAT_SB(sb);
419
420 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
421 *ret_count = 0;
422 return 0;
423 }
424
425 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
426 *ret_count = p_chain->size;
427 return 0;
428 }
429
430 clu = p_chain->dir;
431 count = 0;
432 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
433 count++;
434 if (exfat_ent_get(sb, clu, &clu))
435 return -EIO;
436 if (clu == EXFAT_EOF_CLUSTER)
437 break;
438 }
439
440 *ret_count = count;
441 return 0;
442 }
443