1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4 */
5
6 #include <linux/blkdev.h>
7 #include <linux/slab.h>
8 #include <linux/buffer_head.h>
9
10 #include "exfat_raw.h"
11 #include "exfat_fs.h"
12
13 static const unsigned char free_bit[] = {
14 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/* 0 ~ 19*/
15 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~ 39*/
16 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~ 59*/
17 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~ 79*/
18 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~ 99*/
19 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/
20 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/
21 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/
22 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/
23 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/
24 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/
25 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/
26 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 /*240 ~ 254*/
27 };
28
29 static const unsigned char used_bit[] = {
30 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/* 0 ~ 19*/
31 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~ 39*/
32 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~ 59*/
33 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~ 79*/
34 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~ 99*/
35 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/
36 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/
37 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/
38 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/
39 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/
40 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/
41 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/
42 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 /*240 ~ 255*/
43 };
44
45 /*
46 * Allocation Bitmap Management Functions
47 */
exfat_allocate_bitmap(struct super_block * sb,struct exfat_dentry * ep)48 static int exfat_allocate_bitmap(struct super_block *sb,
49 struct exfat_dentry *ep)
50 {
51 struct exfat_sb_info *sbi = EXFAT_SB(sb);
52 long long map_size;
53 unsigned int i, need_map_size;
54 sector_t sector;
55
56 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
57 map_size = le64_to_cpu(ep->dentry.bitmap.size);
58 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
59 + 1;
60 if (need_map_size != map_size) {
61 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
62 need_map_size, map_size);
63 /*
64 * Only allowed when bogus allocation
65 * bitmap size is large
66 */
67 if (need_map_size > map_size)
68 return -EIO;
69 }
70 sbi->map_sectors = ((need_map_size - 1) >>
71 (sb->s_blocksize_bits)) + 1;
72 sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
73 sizeof(struct buffer_head *), GFP_KERNEL);
74 if (!sbi->vol_amap)
75 return -ENOMEM;
76
77 sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
78 for (i = 0; i < sbi->map_sectors; i++) {
79 sbi->vol_amap[i] = sb_bread(sb, sector + i);
80 if (!sbi->vol_amap[i]) {
81 /* release all buffers and free vol_amap */
82 int j = 0;
83
84 while (j < i)
85 brelse(sbi->vol_amap[j++]);
86
87 kvfree(sbi->vol_amap);
88 sbi->vol_amap = NULL;
89 return -EIO;
90 }
91 }
92
93 return 0;
94 }
95
exfat_load_bitmap(struct super_block * sb)96 int exfat_load_bitmap(struct super_block *sb)
97 {
98 unsigned int i, type;
99 struct exfat_chain clu;
100 struct exfat_sb_info *sbi = EXFAT_SB(sb);
101
102 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
103 while (clu.dir != EXFAT_EOF_CLUSTER) {
104 for (i = 0; i < sbi->dentries_per_clu; i++) {
105 struct exfat_dentry *ep;
106 struct buffer_head *bh;
107
108 ep = exfat_get_dentry(sb, &clu, i, &bh);
109 if (!ep)
110 return -EIO;
111
112 type = exfat_get_entry_type(ep);
113 if (type == TYPE_UNUSED)
114 break;
115 if (type != TYPE_BITMAP)
116 continue;
117 if (ep->dentry.bitmap.flags == 0x0) {
118 int err;
119
120 err = exfat_allocate_bitmap(sb, ep);
121 brelse(bh);
122 return err;
123 }
124 brelse(bh);
125 }
126
127 if (exfat_get_next_cluster(sb, &clu.dir))
128 return -EIO;
129 }
130
131 return -EINVAL;
132 }
133
exfat_free_bitmap(struct exfat_sb_info * sbi)134 void exfat_free_bitmap(struct exfat_sb_info *sbi)
135 {
136 int i;
137
138 for (i = 0; i < sbi->map_sectors; i++)
139 __brelse(sbi->vol_amap[i]);
140
141 kvfree(sbi->vol_amap);
142 }
143
exfat_set_bitmap(struct inode * inode,unsigned int clu,bool sync)144 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)
145 {
146 int i, b;
147 unsigned int ent_idx;
148 struct super_block *sb = inode->i_sb;
149 struct exfat_sb_info *sbi = EXFAT_SB(sb);
150
151 if (!is_valid_cluster(sbi, clu))
152 return -EINVAL;
153
154 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
155 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
156 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
157
158 set_bit_le(b, sbi->vol_amap[i]->b_data);
159 exfat_update_bh(sbi->vol_amap[i], sync);
160 return 0;
161 }
162
exfat_clear_bitmap(struct inode * inode,unsigned int clu,bool sync)163 void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
164 {
165 int i, b;
166 unsigned int ent_idx;
167 struct super_block *sb = inode->i_sb;
168 struct exfat_sb_info *sbi = EXFAT_SB(sb);
169 struct exfat_mount_options *opts = &sbi->options;
170
171 if (!is_valid_cluster(sbi, clu))
172 return;
173
174 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
175 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
176 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
177
178 clear_bit_le(b, sbi->vol_amap[i]->b_data);
179 exfat_update_bh(sbi->vol_amap[i], sync);
180
181 if (opts->discard) {
182 int ret_discard;
183
184 ret_discard = sb_issue_discard(sb,
185 exfat_cluster_to_sector(sbi, clu),
186 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
187
188 if (ret_discard == -EOPNOTSUPP) {
189 exfat_err(sb, "discard not supported by device, disabling");
190 opts->discard = 0;
191 }
192 }
193 }
194
195 /*
196 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
197 * the cluster heap.
198 */
exfat_find_free_bitmap(struct super_block * sb,unsigned int clu)199 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
200 {
201 unsigned int i, map_i, map_b, ent_idx;
202 unsigned int clu_base, clu_free;
203 unsigned char k, clu_mask;
204 struct exfat_sb_info *sbi = EXFAT_SB(sb);
205
206 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
207 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
208 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK));
209 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
210
211 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
212 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
213
214 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
215 i += BITS_PER_BYTE) {
216 k = *(sbi->vol_amap[map_i]->b_data + map_b);
217 if (clu_mask > 0) {
218 k |= clu_mask;
219 clu_mask = 0;
220 }
221 if (k < 0xFF) {
222 clu_free = clu_base + free_bit[k];
223 if (clu_free < sbi->num_clusters)
224 return clu_free;
225 }
226 clu_base += BITS_PER_BYTE;
227
228 if (++map_b >= sb->s_blocksize ||
229 clu_base >= sbi->num_clusters) {
230 if (++map_i >= sbi->map_sectors) {
231 clu_base = EXFAT_FIRST_CLUSTER;
232 map_i = 0;
233 }
234 map_b = 0;
235 }
236 }
237
238 return EXFAT_EOF_CLUSTER;
239 }
240
exfat_count_used_clusters(struct super_block * sb,unsigned int * ret_count)241 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
242 {
243 struct exfat_sb_info *sbi = EXFAT_SB(sb);
244 unsigned int count = 0;
245 unsigned int i, map_i = 0, map_b = 0;
246 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
247 unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK;
248 unsigned char clu_bits;
249 const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,
250 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};
251
252 total_clus &= ~last_mask;
253 for (i = 0; i < total_clus; i += BITS_PER_BYTE) {
254 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
255 count += used_bit[clu_bits];
256 if (++map_b >= (unsigned int)sb->s_blocksize) {
257 map_i++;
258 map_b = 0;
259 }
260 }
261
262 if (last_mask) {
263 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
264 clu_bits &= last_bit_mask[last_mask];
265 count += used_bit[clu_bits];
266 }
267
268 *ret_count = count;
269 return 0;
270 }
271
exfat_trim_fs(struct inode * inode,struct fstrim_range * range)272 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
273 {
274 unsigned int trim_begin, trim_end, count, next_free_clu;
275 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
276 struct super_block *sb = inode->i_sb;
277 struct exfat_sb_info *sbi = EXFAT_SB(sb);
278 int err = 0;
279
280 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
281 EXFAT_FIRST_CLUSTER);
282 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
283 trim_minlen = range->minlen >> sbi->cluster_size_bits;
284
285 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
286 return -EINVAL;
287
288 if (clu_end >= sbi->num_clusters)
289 clu_end = sbi->num_clusters - 1;
290
291 mutex_lock(&sbi->bitmap_lock);
292
293 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
294 if (trim_begin == EXFAT_EOF_CLUSTER)
295 goto unlock;
296
297 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
298 if (next_free_clu == EXFAT_EOF_CLUSTER)
299 goto unlock;
300
301 do {
302 if (next_free_clu == trim_end + 1) {
303 /* extend trim range for continuous free cluster */
304 trim_end++;
305 } else {
306 /* trim current range if it's larger than trim_minlen */
307 count = trim_end - trim_begin + 1;
308 if (count >= trim_minlen) {
309 err = sb_issue_discard(sb,
310 exfat_cluster_to_sector(sbi, trim_begin),
311 count * sbi->sect_per_clus, GFP_NOFS, 0);
312 if (err)
313 goto unlock;
314
315 trimmed_total += count;
316 }
317
318 /* set next start point of the free hole */
319 trim_begin = trim_end = next_free_clu;
320 }
321
322 if (next_free_clu >= clu_end)
323 break;
324
325 if (fatal_signal_pending(current)) {
326 err = -ERESTARTSYS;
327 goto unlock;
328 }
329
330 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
331 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
332 next_free_clu > trim_end);
333
334 /* try to trim remainder */
335 count = trim_end - trim_begin + 1;
336 if (count >= trim_minlen) {
337 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
338 count * sbi->sect_per_clus, GFP_NOFS, 0);
339 if (err)
340 goto unlock;
341
342 trimmed_total += count;
343 }
344
345 unlock:
346 mutex_unlock(&sbi->bitmap_lock);
347 range->len = trimmed_total << sbi->cluster_size_bits;
348
349 return err;
350 }
351