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 = kmalloc_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 kfree(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, NULL);
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 kfree(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 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
152 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
153 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
154 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
155
156 set_bit_le(b, sbi->vol_amap[i]->b_data);
157 exfat_update_bh(sbi->vol_amap[i], sync);
158 return 0;
159 }
160
exfat_clear_bitmap(struct inode * inode,unsigned int clu,bool sync)161 void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
162 {
163 int i, b;
164 unsigned int ent_idx;
165 struct super_block *sb = inode->i_sb;
166 struct exfat_sb_info *sbi = EXFAT_SB(sb);
167 struct exfat_mount_options *opts = &sbi->options;
168
169 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
170 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
171 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
172 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
173
174 clear_bit_le(b, sbi->vol_amap[i]->b_data);
175 exfat_update_bh(sbi->vol_amap[i], sync);
176
177 if (opts->discard) {
178 int ret_discard;
179
180 ret_discard = sb_issue_discard(sb,
181 exfat_cluster_to_sector(sbi, clu),
182 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
183
184 if (ret_discard == -EOPNOTSUPP) {
185 exfat_err(sb, "discard not supported by device, disabling");
186 opts->discard = 0;
187 }
188 }
189 }
190
191 /*
192 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
193 * the cluster heap.
194 */
exfat_find_free_bitmap(struct super_block * sb,unsigned int clu)195 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
196 {
197 unsigned int i, map_i, map_b, ent_idx;
198 unsigned int clu_base, clu_free;
199 unsigned char k, clu_mask;
200 struct exfat_sb_info *sbi = EXFAT_SB(sb);
201
202 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
203 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
204 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK));
205 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
206
207 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
208 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
209
210 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
211 i += BITS_PER_BYTE) {
212 k = *(sbi->vol_amap[map_i]->b_data + map_b);
213 if (clu_mask > 0) {
214 k |= clu_mask;
215 clu_mask = 0;
216 }
217 if (k < 0xFF) {
218 clu_free = clu_base + free_bit[k];
219 if (clu_free < sbi->num_clusters)
220 return clu_free;
221 }
222 clu_base += BITS_PER_BYTE;
223
224 if (++map_b >= sb->s_blocksize ||
225 clu_base >= sbi->num_clusters) {
226 if (++map_i >= sbi->map_sectors) {
227 clu_base = EXFAT_FIRST_CLUSTER;
228 map_i = 0;
229 }
230 map_b = 0;
231 }
232 }
233
234 return EXFAT_EOF_CLUSTER;
235 }
236
exfat_count_used_clusters(struct super_block * sb,unsigned int * ret_count)237 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
238 {
239 struct exfat_sb_info *sbi = EXFAT_SB(sb);
240 unsigned int count = 0;
241 unsigned int i, map_i = 0, map_b = 0;
242 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
243 unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK;
244 unsigned char clu_bits;
245 const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,
246 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};
247
248 total_clus &= ~last_mask;
249 for (i = 0; i < total_clus; i += BITS_PER_BYTE) {
250 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
251 count += used_bit[clu_bits];
252 if (++map_b >= (unsigned int)sb->s_blocksize) {
253 map_i++;
254 map_b = 0;
255 }
256 }
257
258 if (last_mask) {
259 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
260 clu_bits &= last_bit_mask[last_mask];
261 count += used_bit[clu_bits];
262 }
263
264 *ret_count = count;
265 return 0;
266 }
267
exfat_trim_fs(struct inode * inode,struct fstrim_range * range)268 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
269 {
270 unsigned int trim_begin, trim_end, count, next_free_clu;
271 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
272 struct super_block *sb = inode->i_sb;
273 struct exfat_sb_info *sbi = EXFAT_SB(sb);
274 int err = 0;
275
276 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
277 EXFAT_FIRST_CLUSTER);
278 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
279 trim_minlen = range->minlen >> sbi->cluster_size_bits;
280
281 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
282 return -EINVAL;
283
284 if (clu_end >= sbi->num_clusters)
285 clu_end = sbi->num_clusters - 1;
286
287 mutex_lock(&sbi->bitmap_lock);
288
289 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
290 if (trim_begin == EXFAT_EOF_CLUSTER)
291 goto unlock;
292
293 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
294 if (next_free_clu == EXFAT_EOF_CLUSTER)
295 goto unlock;
296
297 do {
298 if (next_free_clu == trim_end + 1) {
299 /* extend trim range for continuous free cluster */
300 trim_end++;
301 } else {
302 /* trim current range if it's larger than trim_minlen */
303 count = trim_end - trim_begin + 1;
304 if (count >= trim_minlen) {
305 err = sb_issue_discard(sb,
306 exfat_cluster_to_sector(sbi, trim_begin),
307 count * sbi->sect_per_clus, GFP_NOFS, 0);
308 if (err)
309 goto unlock;
310
311 trimmed_total += count;
312 }
313
314 /* set next start point of the free hole */
315 trim_begin = trim_end = next_free_clu;
316 }
317
318 if (next_free_clu >= clu_end)
319 break;
320
321 if (fatal_signal_pending(current)) {
322 err = -ERESTARTSYS;
323 goto unlock;
324 }
325
326 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
327 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
328 next_free_clu > trim_end);
329
330 /* try to trim remainder */
331 count = trim_end - trim_begin + 1;
332 if (count >= trim_minlen) {
333 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
334 count * sbi->sect_per_clus, GFP_NOFS, 0);
335 if (err)
336 goto unlock;
337
338 trimmed_total += count;
339 }
340
341 unlock:
342 mutex_unlock(&sbi->bitmap_lock);
343 range->len = trimmed_total << sbi->cluster_size_bits;
344
345 return err;
346 }
347
