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/bitmap.h>
9 #include <linux/buffer_head.h>
10
11 #include "exfat_raw.h"
12 #include "exfat_fs.h"
13
14 #if BITS_PER_LONG == 32
15 #define __le_long __le32
16 #define lel_to_cpu(A) le32_to_cpu(A)
17 #define cpu_to_lel(A) cpu_to_le32(A)
18 #elif BITS_PER_LONG == 64
19 #define __le_long __le64
20 #define lel_to_cpu(A) le64_to_cpu(A)
21 #define cpu_to_lel(A) cpu_to_le64(A)
22 #else
23 #error "BITS_PER_LONG not 32 or 64"
24 #endif
25
26 /*
27 * Allocation Bitmap Management Functions
28 */
29 static int exfat_allocate_bitmap(struct super_block *sb,
30 struct exfat_dentry *ep)
31 {
32 struct exfat_sb_info *sbi = EXFAT_SB(sb);
33 long long map_size;
34 unsigned int i, need_map_size;
35 sector_t sector;
36
37 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
38 map_size = le64_to_cpu(ep->dentry.bitmap.size);
39 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
40 + 1;
41 if (need_map_size != map_size) {
42 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
43 need_map_size, map_size);
44 /*
45 * Only allowed when bogus allocation
46 * bitmap size is large
47 */
48 if (need_map_size > map_size)
49 return -EIO;
50 }
51 sbi->map_sectors = ((need_map_size - 1) >>
52 (sb->s_blocksize_bits)) + 1;
53 sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
54 sizeof(struct buffer_head *), GFP_KERNEL);
55 if (!sbi->vol_amap)
56 return -ENOMEM;
57
58 sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
59 for (i = 0; i < sbi->map_sectors; i++) {
60 sbi->vol_amap[i] = sb_bread(sb, sector + i);
61 if (!sbi->vol_amap[i]) {
62 /* release all buffers and free vol_amap */
63 int j = 0;
64
65 while (j < i)
66 brelse(sbi->vol_amap[j++]);
67
68 kvfree(sbi->vol_amap);
69 sbi->vol_amap = NULL;
70 return -EIO;
71 }
72 }
73
74 return 0;
75 }
76
77 int exfat_load_bitmap(struct super_block *sb)
78 {
79 unsigned int i, type;
80 struct exfat_chain clu;
81 struct exfat_sb_info *sbi = EXFAT_SB(sb);
82
83 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
84 while (clu.dir != EXFAT_EOF_CLUSTER) {
85 for (i = 0; i < sbi->dentries_per_clu; i++) {
86 struct exfat_dentry *ep;
87 struct buffer_head *bh;
88
89 ep = exfat_get_dentry(sb, &clu, i, &bh);
90 if (!ep)
91 return -EIO;
92
93 type = exfat_get_entry_type(ep);
94 if (type == TYPE_UNUSED)
95 break;
96 if (type != TYPE_BITMAP)
97 continue;
98 if (ep->dentry.bitmap.flags == 0x0) {
99 int err;
100
101 err = exfat_allocate_bitmap(sb, ep);
102 brelse(bh);
103 return err;
104 }
105 brelse(bh);
106 }
107
108 if (exfat_get_next_cluster(sb, &clu.dir))
109 return -EIO;
110 }
111
112 return -EINVAL;
113 }
114
115 void exfat_free_bitmap(struct exfat_sb_info *sbi)
116 {
117 int i;
118
119 for (i = 0; i < sbi->map_sectors; i++)
120 __brelse(sbi->vol_amap[i]);
121
122 kvfree(sbi->vol_amap);
123 }
124
125 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)
126 {
127 int i, b;
128 unsigned int ent_idx;
129 struct super_block *sb = inode->i_sb;
130 struct exfat_sb_info *sbi = EXFAT_SB(sb);
131
132 if (!is_valid_cluster(sbi, clu))
133 return -EINVAL;
134
135 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
136 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
137 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
138
139 set_bit_le(b, sbi->vol_amap[i]->b_data);
140 exfat_update_bh(sbi->vol_amap[i], sync);
141 return 0;
142 }
143
144 void exfat_clear_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 struct exfat_mount_options *opts = &sbi->options;
151
152 if (!is_valid_cluster(sbi, clu))
153 return;
154
155 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
156 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
157 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
158
159 clear_bit_le(b, sbi->vol_amap[i]->b_data);
160 exfat_update_bh(sbi->vol_amap[i], sync);
161
162 if (opts->discard) {
163 int ret_discard;
164
165 ret_discard = sb_issue_discard(sb,
166 exfat_cluster_to_sector(sbi, clu),
167 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
168
169 if (ret_discard == -EOPNOTSUPP) {
170 exfat_err(sb, "discard not supported by device, disabling");
171 opts->discard = 0;
172 }
173 }
174 }
175
176 /*
177 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
178 * the cluster heap.
179 */
180 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
181 {
182 unsigned int i, map_i, map_b, ent_idx;
183 unsigned int clu_base, clu_free;
184 unsigned long clu_bits, clu_mask;
185 struct exfat_sb_info *sbi = EXFAT_SB(sb);
186 __le_long bitval;
187
188 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
189 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
190 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
191 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
192
193 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
194 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
195
196 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
197 i += BITS_PER_LONG) {
198 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
199 if (clu_mask > 0) {
200 bitval |= cpu_to_lel(clu_mask);
201 clu_mask = 0;
202 }
203 if (lel_to_cpu(bitval) != ULONG_MAX) {
204 clu_bits = lel_to_cpu(bitval);
205 clu_free = clu_base + ffz(clu_bits);
206 if (clu_free < sbi->num_clusters)
207 return clu_free;
208 }
209 clu_base += BITS_PER_LONG;
210 map_b += sizeof(long);
211
212 if (map_b >= sb->s_blocksize ||
213 clu_base >= sbi->num_clusters) {
214 if (++map_i >= sbi->map_sectors) {
215 clu_base = EXFAT_FIRST_CLUSTER;
216 map_i = 0;
217 }
218 map_b = 0;
219 }
220 }
221
222 return EXFAT_EOF_CLUSTER;
223 }
224
225 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
226 {
227 struct exfat_sb_info *sbi = EXFAT_SB(sb);
228 unsigned int count = 0;
229 unsigned int i, map_i = 0, map_b = 0;
230 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
231 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1);
232 unsigned long *bitmap, clu_bits;
233
234 total_clus &= ~last_mask;
235 for (i = 0; i < total_clus; i += BITS_PER_LONG) {
236 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
237 count += hweight_long(*bitmap);
238 map_b += sizeof(long);
239 if (map_b >= (unsigned int)sb->s_blocksize) {
240 map_i++;
241 map_b = 0;
242 }
243 }
244
245 if (last_mask) {
246 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
247 clu_bits = lel_to_cpu(*(__le_long *)bitmap);
248 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
249 }
250
251 *ret_count = count;
252 return 0;
253 }
254
255 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
256 {
257 unsigned int trim_begin, trim_end, count, next_free_clu;
258 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
259 struct super_block *sb = inode->i_sb;
260 struct exfat_sb_info *sbi = EXFAT_SB(sb);
261 int err = 0;
262
263 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
264 EXFAT_FIRST_CLUSTER);
265 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
266 trim_minlen = range->minlen >> sbi->cluster_size_bits;
267
268 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
269 return -EINVAL;
270
271 if (clu_end >= sbi->num_clusters)
272 clu_end = sbi->num_clusters - 1;
273
274 mutex_lock(&sbi->bitmap_lock);
275
276 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
277 if (trim_begin == EXFAT_EOF_CLUSTER)
278 goto unlock;
279
280 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
281 if (next_free_clu == EXFAT_EOF_CLUSTER)
282 goto unlock;
283
284 do {
285 if (next_free_clu == trim_end + 1) {
286 /* extend trim range for continuous free cluster */
287 trim_end++;
288 } else {
289 /* trim current range if it's larger than trim_minlen */
290 count = trim_end - trim_begin + 1;
291 if (count >= trim_minlen) {
292 err = sb_issue_discard(sb,
293 exfat_cluster_to_sector(sbi, trim_begin),
294 count * sbi->sect_per_clus, GFP_NOFS, 0);
295 if (err)
296 goto unlock;
297
298 trimmed_total += count;
299 }
300
301 /* set next start point of the free hole */
302 trim_begin = trim_end = next_free_clu;
303 }
304
305 if (next_free_clu >= clu_end)
306 break;
307
308 if (fatal_signal_pending(current)) {
309 err = -ERESTARTSYS;
310 goto unlock;
311 }
312
313 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
314 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
315 next_free_clu > trim_end);
316
317 /* try to trim remainder */
318 count = trim_end - trim_begin + 1;
319 if (count >= trim_minlen) {
320 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
321 count * sbi->sect_per_clus, GFP_NOFS, 0);
322 if (err)
323 goto unlock;
324
325 trimmed_total += count;
326 }
327
328 unlock:
329 mutex_unlock(&sbi->bitmap_lock);
330 range->len = trimmed_total << sbi->cluster_size_bits;
331
332 return err;
333 }
334
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.