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
151 if (!is_valid_cluster(sbi, clu))
152 return -EIO;
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 if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
159 return -EIO;
160
161 clear_bit_le(b, sbi->vol_amap[i]->b_data);
162
163 exfat_update_bh(sbi->vol_amap[i], sync);
164
165 return 0;
166 }
167
168 /*
169 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
170 * the cluster heap.
171 */
exfat_find_free_bitmap(struct super_block * sb,unsigned int clu)172 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
173 {
174 unsigned int i, map_i, map_b, ent_idx;
175 unsigned int clu_base, clu_free;
176 unsigned long clu_bits, clu_mask;
177 struct exfat_sb_info *sbi = EXFAT_SB(sb);
178 __le_long bitval;
179
180 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
181 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
182 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
183 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
184
185 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
186 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
187
188 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
189 i += BITS_PER_LONG) {
190 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
191 if (clu_mask > 0) {
192 bitval |= cpu_to_lel(clu_mask);
193 clu_mask = 0;
194 }
195 if (lel_to_cpu(bitval) != ULONG_MAX) {
196 clu_bits = lel_to_cpu(bitval);
197 clu_free = clu_base + ffz(clu_bits);
198 if (clu_free < sbi->num_clusters)
199 return clu_free;
200 }
201 clu_base += BITS_PER_LONG;
202 map_b += sizeof(long);
203
204 if (map_b >= sb->s_blocksize ||
205 clu_base >= sbi->num_clusters) {
206 if (++map_i >= sbi->map_sectors) {
207 clu_base = EXFAT_FIRST_CLUSTER;
208 map_i = 0;
209 }
210 map_b = 0;
211 }
212 }
213
214 return EXFAT_EOF_CLUSTER;
215 }
216
exfat_count_used_clusters(struct super_block * sb,unsigned int * ret_count)217 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
218 {
219 struct exfat_sb_info *sbi = EXFAT_SB(sb);
220 unsigned int count = 0;
221 unsigned int i, map_i = 0, map_b = 0;
222 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
223 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1);
224 unsigned long *bitmap, clu_bits;
225
226 total_clus &= ~last_mask;
227 for (i = 0; i < total_clus; i += BITS_PER_LONG) {
228 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
229 count += hweight_long(*bitmap);
230 map_b += sizeof(long);
231 if (map_b >= (unsigned int)sb->s_blocksize) {
232 map_i++;
233 map_b = 0;
234 }
235 }
236
237 if (last_mask) {
238 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
239 clu_bits = lel_to_cpu(*(__le_long *)bitmap);
240 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
241 }
242
243 *ret_count = count;
244 return 0;
245 }
246
exfat_trim_fs(struct inode * inode,struct fstrim_range * range)247 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
248 {
249 unsigned int trim_begin, trim_end, count, next_free_clu;
250 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
251 struct super_block *sb = inode->i_sb;
252 struct exfat_sb_info *sbi = EXFAT_SB(sb);
253 int err = 0;
254
255 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
256 EXFAT_FIRST_CLUSTER);
257 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
258 trim_minlen = range->minlen >> sbi->cluster_size_bits;
259
260 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
261 return -EINVAL;
262
263 if (clu_end >= sbi->num_clusters)
264 clu_end = sbi->num_clusters - 1;
265
266 mutex_lock(&sbi->bitmap_lock);
267
268 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
269 if (trim_begin == EXFAT_EOF_CLUSTER)
270 goto unlock;
271
272 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
273 if (next_free_clu == EXFAT_EOF_CLUSTER)
274 goto unlock;
275
276 do {
277 if (next_free_clu == trim_end + 1) {
278 /* extend trim range for continuous free cluster */
279 trim_end++;
280 } else {
281 /* trim current range if it's larger than trim_minlen */
282 count = trim_end - trim_begin + 1;
283 if (count >= trim_minlen) {
284 err = sb_issue_discard(sb,
285 exfat_cluster_to_sector(sbi, trim_begin),
286 count * sbi->sect_per_clus, GFP_NOFS, 0);
287 if (err)
288 goto unlock;
289
290 trimmed_total += count;
291 }
292
293 /* set next start point of the free hole */
294 trim_begin = trim_end = next_free_clu;
295 }
296
297 if (next_free_clu >= clu_end)
298 break;
299
300 if (fatal_signal_pending(current)) {
301 err = -ERESTARTSYS;
302 goto unlock;
303 }
304
305 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
306 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
307 next_free_clu > trim_end);
308
309 /* try to trim remainder */
310 count = trim_end - trim_begin + 1;
311 if (count >= trim_minlen) {
312 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
313 count * sbi->sect_per_clus, GFP_NOFS, 0);
314 if (err)
315 goto unlock;
316
317 trimmed_total += count;
318 }
319
320 unlock:
321 mutex_unlock(&sbi->bitmap_lock);
322 range->len = trimmed_total << sbi->cluster_size_bits;
323
324 return err;
325 }
326