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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
13static 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
37static 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
61int 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
84static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
85 unsigned int clus)
86{
87 if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus)
88 return false;
89 return true;
90}
91
92int exfat_ent_get(struct super_block *sb, unsigned int loc,
93 unsigned int *content)
94{
95 struct exfat_sb_info *sbi = EXFAT_SB(sb);
96 int err;
97
98 if (!is_valid_cluster(sbi, loc)) {
99 exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)",
100 loc);
101 return -EIO;
102 }
103
104 err = __exfat_ent_get(sb, loc, content);
105 if (err) {
106 exfat_fs_error(sb,
107 "failed to access to FAT (entry 0x%08x, err:%d)",
108 loc, err);
109 return err;
110 }
111
112 if (*content == EXFAT_FREE_CLUSTER) {
113 exfat_fs_error(sb,
114 "invalid access to FAT free cluster (entry 0x%08x)",
115 loc);
116 return -EIO;
117 }
118
119 if (*content == EXFAT_BAD_CLUSTER) {
120 exfat_fs_error(sb,
121 "invalid access to FAT bad cluster (entry 0x%08x)",
122 loc);
123 return -EIO;
124 }
125
126 if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) {
127 exfat_fs_error(sb,
128 "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)",
129 loc, *content);
130 return -EIO;
131 }
132
133 return 0;
134}
135
136int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
137 unsigned int len)
138{
139 if (!len)
140 return 0;
141
142 while (len > 1) {
143 if (exfat_ent_set(sb, chain, chain + 1))
144 return -EIO;
145 chain++;
146 len--;
147 }
148
149 if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER))
150 return -EIO;
151 return 0;
152}
153
154int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
155{
156 unsigned int num_clusters = 0;
157 unsigned int clu;
158 struct super_block *sb = inode->i_sb;
159 struct exfat_sb_info *sbi = EXFAT_SB(sb);
160
161 /* invalid cluster number */
162 if (p_chain->dir == EXFAT_FREE_CLUSTER ||
163 p_chain->dir == EXFAT_EOF_CLUSTER ||
164 p_chain->dir < EXFAT_FIRST_CLUSTER)
165 return 0;
166
167 /* no cluster to truncate */
168 if (p_chain->size == 0)
169 return 0;
170
171 /* check cluster validation */
172 if (!is_valid_cluster(sbi, p_chain->dir)) {
173 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
174 return -EIO;
175 }
176
177 clu = p_chain->dir;
178
179 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
180 do {
181 exfat_clear_bitmap(inode, clu);
182 clu++;
183
184 num_clusters++;
185 } while (num_clusters < p_chain->size);
186 } else {
187 do {
188 exfat_clear_bitmap(inode, clu);
189
190 if (exfat_get_next_cluster(sb, &clu))
191 goto dec_used_clus;
192
193 num_clusters++;
194 } while (clu != EXFAT_EOF_CLUSTER);
195 }
196
197dec_used_clus:
198 sbi->used_clusters -= num_clusters;
199 return 0;
200}
201
202int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
203 unsigned int *ret_clu)
204{
205 unsigned int clu, next;
206 unsigned int count = 0;
207
208 next = p_chain->dir;
209 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
210 *ret_clu = next + p_chain->size - 1;
211 return 0;
212 }
213
214 do {
215 count++;
216 clu = next;
217 if (exfat_ent_get(sb, clu, &next))
218 return -EIO;
219 } while (next != EXFAT_EOF_CLUSTER);
220
221 if (p_chain->size != count) {
222 exfat_fs_error(sb,
223 "bogus directory size (clus : ondisk(%d) != counted(%d))",
224 p_chain->size, count);
225 return -EIO;
226 }
227
228 *ret_clu = clu;
229 return 0;
230}
231
232int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
233{
234 struct super_block *sb = dir->i_sb;
235 struct exfat_sb_info *sbi = EXFAT_SB(sb);
236 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
237 int nr_bhs = MAX_BUF_PER_PAGE;
238 sector_t blknr, last_blknr;
239 int err, i, n;
240
241 blknr = exfat_cluster_to_sector(sbi, clu);
242 last_blknr = blknr + sbi->sect_per_clus;
243
244 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
245 exfat_fs_error_ratelimit(sb,
246 "%s: out of range(sect:%llu len:%u)",
247 __func__, (unsigned long long)blknr,
248 sbi->sect_per_clus);
249 return -EIO;
250 }
251
252 /* Zeroing the unused blocks on this cluster */
253 while (blknr < last_blknr) {
254 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) {
255 bhs[n] = sb_getblk(sb, blknr);
256 if (!bhs[n]) {
257 err = -ENOMEM;
258 goto release_bhs;
259 }
260 memset(bhs[n]->b_data, 0, sb->s_blocksize);
261 }
262
263 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
264 if (err)
265 goto release_bhs;
266
267 for (i = 0; i < n; i++)
268 brelse(bhs[i]);
269 }
270 return 0;
271
272release_bhs:
273 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
274 for (i = 0; i < n; i++)
275 bforget(bhs[i]);
276 return err;
277}
278
279int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
280 struct exfat_chain *p_chain)
281{
282 int ret = -ENOSPC;
283 unsigned int num_clusters = 0, total_cnt;
284 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
285 struct super_block *sb = inode->i_sb;
286 struct exfat_sb_info *sbi = EXFAT_SB(sb);
287
288 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
289
290 if (unlikely(total_cnt < sbi->used_clusters)) {
291 exfat_fs_error_ratelimit(sb,
292 "%s: invalid used clusters(t:%u,u:%u)\n",
293 __func__, total_cnt, sbi->used_clusters);
294 return -EIO;
295 }
296
297 if (num_alloc > total_cnt - sbi->used_clusters)
298 return -ENOSPC;
299
300 hint_clu = p_chain->dir;
301 /* find new cluster */
302 if (hint_clu == EXFAT_EOF_CLUSTER) {
303 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
304 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
305 sbi->clu_srch_ptr);
306 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
307 }
308
309 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
310 if (hint_clu == EXFAT_EOF_CLUSTER)
311 return -ENOSPC;
312 }
313
314 /* check cluster validation */
315 if (!is_valid_cluster(sbi, hint_clu)) {
316 exfat_err(sb, "hint_cluster is invalid (%u)",
317 hint_clu);
318 hint_clu = EXFAT_FIRST_CLUSTER;
319 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
320 if (exfat_chain_cont_cluster(sb, p_chain->dir,
321 num_clusters))
322 return -EIO;
323 p_chain->flags = ALLOC_FAT_CHAIN;
324 }
325 }
326
327 p_chain->dir = EXFAT_EOF_CLUSTER;
328
329 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
330 EXFAT_EOF_CLUSTER) {
331 if (new_clu != hint_clu &&
332 p_chain->flags == ALLOC_NO_FAT_CHAIN) {
333 if (exfat_chain_cont_cluster(sb, p_chain->dir,
334 num_clusters)) {
335 ret = -EIO;
336 goto free_cluster;
337 }
338 p_chain->flags = ALLOC_FAT_CHAIN;
339 }
340
341 /* update allocation bitmap */
342 if (exfat_set_bitmap(inode, new_clu)) {
343 ret = -EIO;
344 goto free_cluster;
345 }
346
347 num_clusters++;
348
349 /* update FAT table */
350 if (p_chain->flags == ALLOC_FAT_CHAIN) {
351 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
352 ret = -EIO;
353 goto free_cluster;
354 }
355 }
356
357 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
358 p_chain->dir = new_clu;
359 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
360 if (exfat_ent_set(sb, last_clu, new_clu)) {
361 ret = -EIO;
362 goto free_cluster;
363 }
364 }
365 last_clu = new_clu;
366
367 if (--num_alloc == 0) {
368 sbi->clu_srch_ptr = hint_clu;
369 sbi->used_clusters += num_clusters;
370
371 p_chain->size += num_clusters;
372 return 0;
373 }
374
375 hint_clu = new_clu + 1;
376 if (hint_clu >= sbi->num_clusters) {
377 hint_clu = EXFAT_FIRST_CLUSTER;
378
379 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
380 if (exfat_chain_cont_cluster(sb, p_chain->dir,
381 num_clusters)) {
382 ret = -EIO;
383 goto free_cluster;
384 }
385 p_chain->flags = ALLOC_FAT_CHAIN;
386 }
387 }
388 }
389free_cluster:
390 if (num_clusters)
391 exfat_free_cluster(inode, p_chain);
392 return ret;
393}
394
395int exfat_count_num_clusters(struct super_block *sb,
396 struct exfat_chain *p_chain, unsigned int *ret_count)
397{
398 unsigned int i, count;
399 unsigned int clu;
400 struct exfat_sb_info *sbi = EXFAT_SB(sb);
401
402 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
403 *ret_count = 0;
404 return 0;
405 }
406
407 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
408 *ret_count = p_chain->size;
409 return 0;
410 }
411
412 clu = p_chain->dir;
413 count = 0;
414 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
415 count++;
416 if (exfat_ent_get(sb, clu, &clu))
417 return -EIO;
418 if (clu == EXFAT_EOF_CLUSTER)
419 break;
420 }
421
422 *ret_count = count;
423 return 0;
424}