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 */
exfat_allocate_bitmap(struct super_block * sb,struct exfat_dentry * ep)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
exfat_load_bitmap(struct super_block * sb)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_BITMAP &&
95 ep->dentry.bitmap.flags == 0x0) {
96 int err;
97
98 err = exfat_allocate_bitmap(sb, ep);
99 brelse(bh);
100 return err;
101 }
102 brelse(bh);
103
104 if (type == TYPE_UNUSED)
105 return -EINVAL;
106 }
107
108 if (exfat_get_next_cluster(sb, &clu.dir))
109 return -EIO;
110 }
111
112 return -EINVAL;
113 }
114
exfat_free_bitmap(struct exfat_sb_info * sbi)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
exfat_set_bitmap(struct inode * inode,unsigned int clu,bool sync)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
exfat_clear_bitmap(struct inode * inode,unsigned int clu,bool sync)144 int 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 -EIO;
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 if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
160 return -EIO;
161
162 clear_bit_le(b, sbi->vol_amap[i]->b_data);
163
164 exfat_update_bh(sbi->vol_amap[i], sync);
165
166 if (opts->discard) {
167 int ret_discard;
168
169 ret_discard = sb_issue_discard(sb,
170 exfat_cluster_to_sector(sbi, clu),
171 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
172
173 if (ret_discard == -EOPNOTSUPP) {
174 exfat_err(sb, "discard not supported by device, disabling");
175 opts->discard = 0;
176 }
177 }
178
179 return 0;
180 }
181
182 /*
183 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
184 * the cluster heap.
185 */
exfat_find_free_bitmap(struct super_block * sb,unsigned int clu)186 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
187 {
188 unsigned int i, map_i, map_b, ent_idx;
189 unsigned int clu_base, clu_free;
190 unsigned long clu_bits, clu_mask;
191 struct exfat_sb_info *sbi = EXFAT_SB(sb);
192 __le_long bitval;
193
194 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
195 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
196 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
197 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
198
199 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
200 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
201
202 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
203 i += BITS_PER_LONG) {
204 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
205 if (clu_mask > 0) {
206 bitval |= cpu_to_lel(clu_mask);
207 clu_mask = 0;
208 }
209 if (lel_to_cpu(bitval) != ULONG_MAX) {
210 clu_bits = lel_to_cpu(bitval);
211 clu_free = clu_base + ffz(clu_bits);
212 if (clu_free < sbi->num_clusters)
213 return clu_free;
214 }
215 clu_base += BITS_PER_LONG;
216 map_b += sizeof(long);
217
218 if (map_b >= sb->s_blocksize ||
219 clu_base >= sbi->num_clusters) {
220 if (++map_i >= sbi->map_sectors) {
221 clu_base = EXFAT_FIRST_CLUSTER;
222 map_i = 0;
223 }
224 map_b = 0;
225 }
226 }
227
228 return EXFAT_EOF_CLUSTER;
229 }
230
exfat_count_used_clusters(struct super_block * sb,unsigned int * ret_count)231 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
232 {
233 struct exfat_sb_info *sbi = EXFAT_SB(sb);
234 unsigned int count = 0;
235 unsigned int i, map_i = 0, map_b = 0;
236 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
237 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1);
238 unsigned long *bitmap, clu_bits;
239
240 total_clus &= ~last_mask;
241 for (i = 0; i < total_clus; i += BITS_PER_LONG) {
242 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
243 count += hweight_long(*bitmap);
244 map_b += sizeof(long);
245 if (map_b >= (unsigned int)sb->s_blocksize) {
246 map_i++;
247 map_b = 0;
248 }
249 }
250
251 if (last_mask) {
252 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
253 clu_bits = lel_to_cpu(*(__le_long *)bitmap);
254 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
255 }
256
257 *ret_count = count;
258 return 0;
259 }
260
exfat_trim_fs(struct inode * inode,struct fstrim_range * range)261 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
262 {
263 unsigned int trim_begin, trim_end, count, next_free_clu;
264 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
265 struct super_block *sb = inode->i_sb;
266 struct exfat_sb_info *sbi = EXFAT_SB(sb);
267 int err = 0;
268
269 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
270 EXFAT_FIRST_CLUSTER);
271 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
272 trim_minlen = range->minlen >> sbi->cluster_size_bits;
273
274 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
275 return -EINVAL;
276
277 if (clu_end >= sbi->num_clusters)
278 clu_end = sbi->num_clusters - 1;
279
280 mutex_lock(&sbi->bitmap_lock);
281
282 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
283 if (trim_begin == EXFAT_EOF_CLUSTER)
284 goto unlock;
285
286 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
287 if (next_free_clu == EXFAT_EOF_CLUSTER)
288 goto unlock;
289
290 do {
291 if (next_free_clu == trim_end + 1) {
292 /* extend trim range for continuous free cluster */
293 trim_end++;
294 } else {
295 /* trim current range if it's larger than trim_minlen */
296 count = trim_end - trim_begin + 1;
297 if (count >= trim_minlen) {
298 err = sb_issue_discard(sb,
299 exfat_cluster_to_sector(sbi, trim_begin),
300 count * sbi->sect_per_clus, GFP_NOFS, 0);
301 if (err)
302 goto unlock;
303
304 trimmed_total += count;
305 }
306
307 /* set next start point of the free hole */
308 trim_begin = trim_end = next_free_clu;
309 }
310
311 if (next_free_clu >= clu_end)
312 break;
313
314 if (fatal_signal_pending(current)) {
315 err = -ERESTARTSYS;
316 goto unlock;
317 }
318
319 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
320 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
321 next_free_clu > trim_end);
322
323 /* try to trim remainder */
324 count = trim_end - trim_begin + 1;
325 if (count >= trim_minlen) {
326 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
327 count * sbi->sect_per_clus, GFP_NOFS, 0);
328 if (err)
329 goto unlock;
330
331 trimmed_total += count;
332 }
333
334 unlock:
335 mutex_unlock(&sbi->bitmap_lock);
336 range->len = trimmed_total << sbi->cluster_size_bits;
337
338 return err;
339 }
340