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 #include <linux/backing-dev.h>
11
12 #include "exfat_raw.h"
13 #include "exfat_fs.h"
14
15 #if BITS_PER_LONG == 32
16 #define __le_long __le32
17 #define lel_to_cpu(A) le32_to_cpu(A)
18 #define cpu_to_lel(A) cpu_to_le32(A)
19 #elif BITS_PER_LONG == 64
20 #define __le_long __le64
21 #define lel_to_cpu(A) le64_to_cpu(A)
22 #define cpu_to_lel(A) cpu_to_le64(A)
23 #else
24 #error "BITS_PER_LONG not 32 or 64"
25 #endif
26
27 /*
28 * Allocation Bitmap Management Functions
29 */
exfat_test_bitmap_range(struct super_block * sb,unsigned int clu,unsigned int count)30 static bool exfat_test_bitmap_range(struct super_block *sb, unsigned int clu,
31 unsigned int count)
32 {
33 struct exfat_sb_info *sbi = EXFAT_SB(sb);
34 unsigned int start = clu;
35 unsigned int end = clu + count;
36 unsigned int ent_idx, i, b;
37 unsigned int bit_offset, bits_to_check;
38 __le_long *bitmap_le;
39 unsigned long mask, word;
40
41 if (!is_valid_cluster(sbi, start) || !is_valid_cluster(sbi, end - 1))
42 return false;
43
44 while (start < end) {
45 ent_idx = CLUSTER_TO_BITMAP_ENT(start);
46 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
47 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
48
49 bitmap_le = (__le_long *)sbi->vol_amap[i]->b_data;
50
51 /* Calculate how many bits we can check in the current word */
52 bit_offset = b % BITS_PER_LONG;
53 bits_to_check = min(end - start,
54 (unsigned int)(BITS_PER_LONG - bit_offset));
55
56 /* Create a bitmask for the range of bits to check */
57 if (bits_to_check >= BITS_PER_LONG)
58 mask = ~0UL;
59 else
60 mask = ((1UL << bits_to_check) - 1) << bit_offset;
61 word = lel_to_cpu(bitmap_le[b / BITS_PER_LONG]);
62
63 /* Check if all bits in the mask are set */
64 if ((word & mask) != mask)
65 return false;
66
67 start += bits_to_check;
68 }
69
70 return true;
71 }
72
exfat_allocate_bitmap(struct super_block * sb,struct exfat_dentry * ep)73 static int exfat_allocate_bitmap(struct super_block *sb,
74 struct exfat_dentry *ep)
75 {
76 struct exfat_sb_info *sbi = EXFAT_SB(sb);
77 long long map_size;
78 unsigned int i, j, need_map_size;
79 sector_t sector, end, ra;
80 blkcnt_t ra_cnt = 0;
81
82 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
83 map_size = le64_to_cpu(ep->dentry.bitmap.size);
84 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
85 + 1;
86 if (need_map_size != map_size) {
87 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
88 need_map_size, map_size);
89 /*
90 * Only allowed when bogus allocation
91 * bitmap size is large
92 */
93 if (need_map_size > map_size)
94 return -EIO;
95 }
96 sbi->map_sectors = ((need_map_size - 1) >>
97 (sb->s_blocksize_bits)) + 1;
98 sbi->vol_amap = kvmalloc_objs(struct buffer_head *, sbi->map_sectors);
99 if (!sbi->vol_amap)
100 return -ENOMEM;
101
102 sector = ra = exfat_cluster_to_sector(sbi, sbi->map_clu);
103 end = sector + sbi->map_sectors - 1;
104
105 for (i = 0; i < sbi->map_sectors; i++) {
106 /* Trigger the next readahead in advance. */
107 exfat_blk_readahead(sb, sector + i, &ra, &ra_cnt, end);
108
109 sbi->vol_amap[i] = sb_bread(sb, sector + i);
110 if (!sbi->vol_amap[i])
111 goto err_out;
112 }
113
114 if (exfat_test_bitmap_range(sb, sbi->map_clu,
115 EXFAT_B_TO_CLU_ROUND_UP(map_size, sbi)) == false)
116 goto err_out;
117
118 return 0;
119
120 err_out:
121 j = 0;
122 /* release all buffers and free vol_amap */
123 while (j < i)
124 brelse(sbi->vol_amap[j++]);
125
126 kvfree(sbi->vol_amap);
127 sbi->vol_amap = NULL;
128 return -EIO;
129 }
130
exfat_load_bitmap(struct super_block * sb)131 int exfat_load_bitmap(struct super_block *sb)
132 {
133 unsigned int i, type;
134 struct exfat_chain clu;
135 struct exfat_sb_info *sbi = EXFAT_SB(sb);
136
137 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
138 while (clu.dir != EXFAT_EOF_CLUSTER) {
139 for (i = 0; i < sbi->dentries_per_clu; i++) {
140 struct exfat_dentry *ep;
141 struct buffer_head *bh;
142
143 ep = exfat_get_dentry(sb, &clu, i, &bh);
144 if (!ep)
145 return -EIO;
146
147 type = exfat_get_entry_type(ep);
148 if (type == TYPE_BITMAP &&
149 ep->dentry.bitmap.flags == 0x0) {
150 int err;
151
152 err = exfat_allocate_bitmap(sb, ep);
153 brelse(bh);
154 return err;
155 }
156 brelse(bh);
157
158 if (type == TYPE_UNUSED)
159 return -EINVAL;
160 }
161
162 if (exfat_get_next_cluster(sb, &clu.dir))
163 return -EIO;
164 }
165
166 return -EINVAL;
167 }
168
exfat_free_bitmap(struct exfat_sb_info * sbi)169 void exfat_free_bitmap(struct exfat_sb_info *sbi)
170 {
171 int i;
172
173 for (i = 0; i < sbi->map_sectors; i++)
174 __brelse(sbi->vol_amap[i]);
175
176 kvfree(sbi->vol_amap);
177 }
178
exfat_set_bitmap(struct super_block * sb,unsigned int clu,bool sync)179 int exfat_set_bitmap(struct super_block *sb, unsigned int clu, bool sync)
180 {
181 int i, b;
182 unsigned int ent_idx;
183 struct exfat_sb_info *sbi = EXFAT_SB(sb);
184
185 if (!is_valid_cluster(sbi, clu))
186 return -EINVAL;
187
188 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
189 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
190 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
191
192 set_bit_le(b, sbi->vol_amap[i]->b_data);
193 exfat_update_bh(sbi->vol_amap[i], sync);
194 return 0;
195 }
196
exfat_clear_bitmap(struct super_block * sb,unsigned int clu,bool sync)197 int exfat_clear_bitmap(struct super_block *sb, unsigned int clu, bool sync)
198 {
199 int i, b;
200 unsigned int ent_idx;
201 struct exfat_sb_info *sbi = EXFAT_SB(sb);
202
203 if (!is_valid_cluster(sbi, clu))
204 return -EIO;
205
206 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
207 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
208 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
209
210 if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
211 return -EIO;
212
213 clear_bit_le(b, sbi->vol_amap[i]->b_data);
214
215 exfat_update_bh(sbi->vol_amap[i], sync);
216
217 return 0;
218 }
219
exfat_test_bitmap(struct super_block * sb,unsigned int clu)220 bool exfat_test_bitmap(struct super_block *sb, unsigned int clu)
221 {
222 int i, b;
223 unsigned int ent_idx;
224 struct exfat_sb_info *sbi = EXFAT_SB(sb);
225
226 if (!sbi->vol_amap)
227 return true;
228
229 if (!is_valid_cluster(sbi, clu))
230 return false;
231
232 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
233 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
234 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
235
236 if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
237 return false;
238
239 return true;
240 }
241
242 /*
243 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
244 * the cluster heap.
245 */
exfat_find_free_bitmap(struct super_block * sb,unsigned int clu)246 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
247 {
248 unsigned int i, map_i, map_b, ent_idx;
249 unsigned int clu_base, clu_free;
250 unsigned long clu_bits, clu_mask;
251 struct exfat_sb_info *sbi = EXFAT_SB(sb);
252 __le_long bitval;
253
254 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
255 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
256 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
257 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
258
259 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
260 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
261
262 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
263 i += BITS_PER_LONG) {
264 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
265 if (clu_mask > 0) {
266 bitval |= cpu_to_lel(clu_mask);
267 clu_mask = 0;
268 }
269 if (lel_to_cpu(bitval) != ULONG_MAX) {
270 clu_bits = lel_to_cpu(bitval);
271 clu_free = clu_base + ffz(clu_bits);
272 if (clu_free < sbi->num_clusters)
273 return clu_free;
274 }
275 clu_base += BITS_PER_LONG;
276 map_b += sizeof(long);
277
278 if (map_b >= sb->s_blocksize ||
279 clu_base >= sbi->num_clusters) {
280 if (++map_i >= sbi->map_sectors) {
281 clu_base = EXFAT_FIRST_CLUSTER;
282 map_i = 0;
283 }
284 map_b = 0;
285 }
286 }
287
288 return EXFAT_EOF_CLUSTER;
289 }
290
exfat_count_used_clusters(struct super_block * sb,unsigned int * ret_count)291 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
292 {
293 struct exfat_sb_info *sbi = EXFAT_SB(sb);
294 unsigned int count = 0;
295 unsigned int i, map_i = 0, map_b = 0;
296 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
297 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1);
298 unsigned long *bitmap, clu_bits;
299
300 total_clus &= ~last_mask;
301 for (i = 0; i < total_clus; i += BITS_PER_LONG) {
302 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
303 count += hweight_long(*bitmap);
304 map_b += sizeof(long);
305 if (map_b >= (unsigned int)sb->s_blocksize) {
306 map_i++;
307 map_b = 0;
308 }
309 }
310
311 if (last_mask) {
312 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
313 clu_bits = lel_to_cpu(*(__le_long *)bitmap);
314 count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
315 }
316
317 *ret_count = count;
318 return 0;
319 }
320
exfat_trim_fs(struct inode * inode,struct fstrim_range * range)321 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
322 {
323 unsigned int trim_begin, trim_end, count, next_free_clu;
324 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
325 struct super_block *sb = inode->i_sb;
326 struct exfat_sb_info *sbi = EXFAT_SB(sb);
327 int err = 0;
328
329 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
330 EXFAT_FIRST_CLUSTER);
331 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
332 trim_minlen = range->minlen >> sbi->cluster_size_bits;
333
334 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
335 return -EINVAL;
336
337 if (clu_end >= sbi->num_clusters)
338 clu_end = sbi->num_clusters - 1;
339
340 mutex_lock(&sbi->bitmap_lock);
341
342 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
343 if (trim_begin == EXFAT_EOF_CLUSTER)
344 goto unlock;
345
346 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
347 if (next_free_clu == EXFAT_EOF_CLUSTER)
348 goto unlock;
349
350 do {
351 if (next_free_clu == trim_end + 1) {
352 /* extend trim range for continuous free cluster */
353 trim_end++;
354 } else {
355 /* trim current range if it's larger than trim_minlen */
356 count = trim_end - trim_begin + 1;
357 if (count >= trim_minlen) {
358 err = sb_issue_discard(sb,
359 exfat_cluster_to_sector(sbi, trim_begin),
360 count * sbi->sect_per_clus, GFP_NOFS, 0);
361 if (err)
362 goto unlock;
363
364 trimmed_total += count;
365 }
366
367 /* set next start point of the free hole */
368 trim_begin = trim_end = next_free_clu;
369 }
370
371 if (next_free_clu >= clu_end)
372 break;
373
374 if (fatal_signal_pending(current)) {
375 err = -ERESTARTSYS;
376 goto unlock;
377 }
378
379 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
380 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
381 next_free_clu > trim_end);
382
383 /* try to trim remainder */
384 count = trim_end - trim_begin + 1;
385 if (count >= trim_minlen) {
386 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
387 count * sbi->sect_per_clus, GFP_NOFS, 0);
388 if (err)
389 goto unlock;
390
391 trimmed_total += count;
392 }
393
394 unlock:
395 mutex_unlock(&sbi->bitmap_lock);
396 range->len = trimmed_total << sbi->cluster_size_bits;
397
398 return err;
399 }
400