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 */
30static 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, clus: start) || !is_valid_cluster(sbi, clus: 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
73static int exfat_allocate_bitmap(struct super_block *sb,
74 struct exfat_dentry *ep)
75{
76 struct exfat_sb_info *sbi = EXFAT_SB(sb);
77 struct blk_plug plug;
78 long long map_size;
79 unsigned int i, j, need_map_size;
80 sector_t sector;
81 unsigned int max_ra_count;
82
83 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
84 map_size = le64_to_cpu(ep->dentry.bitmap.size);
85 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
86 + 1;
87 if (need_map_size != map_size) {
88 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
89 need_map_size, map_size);
90 /*
91 * Only allowed when bogus allocation
92 * bitmap size is large
93 */
94 if (need_map_size > map_size)
95 return -EIO;
96 }
97 sbi->map_sectors = ((need_map_size - 1) >>
98 (sb->s_blocksize_bits)) + 1;
99 sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
100 sizeof(struct buffer_head *), GFP_KERNEL);
101 if (!sbi->vol_amap)
102 return -ENOMEM;
103
104 sector = exfat_cluster_to_sector(sbi, clus: sbi->map_clu);
105 max_ra_count = min(sb->s_bdi->ra_pages, sb->s_bdi->io_pages) <<
106 (PAGE_SHIFT - sb->s_blocksize_bits);
107 for (i = 0; i < sbi->map_sectors; i++) {
108 /* Trigger the next readahead in advance. */
109 if (max_ra_count && 0 == (i % max_ra_count)) {
110 blk_start_plug(&plug);
111 for (j = i; j < min(max_ra_count, sbi->map_sectors - i) + i; j++)
112 sb_breadahead(sb, block: sector + j);
113 blk_finish_plug(&plug);
114 }
115
116 sbi->vol_amap[i] = sb_bread(sb, block: sector + i);
117 if (!sbi->vol_amap[i])
118 goto err_out;
119 }
120
121 if (exfat_test_bitmap_range(sb, clu: sbi->map_clu,
122 EXFAT_B_TO_CLU_ROUND_UP(map_size, sbi)) == false)
123 goto err_out;
124
125 return 0;
126
127err_out:
128 j = 0;
129 /* release all buffers and free vol_amap */
130 while (j < i)
131 brelse(bh: sbi->vol_amap[j++]);
132
133 kvfree(addr: sbi->vol_amap);
134 sbi->vol_amap = NULL;
135 return -EIO;
136}
137
138int exfat_load_bitmap(struct super_block *sb)
139{
140 unsigned int i, type;
141 struct exfat_chain clu;
142 struct exfat_sb_info *sbi = EXFAT_SB(sb);
143
144 exfat_chain_set(ec: &clu, dir: sbi->root_dir, size: 0, ALLOC_FAT_CHAIN);
145 while (clu.dir != EXFAT_EOF_CLUSTER) {
146 for (i = 0; i < sbi->dentries_per_clu; i++) {
147 struct exfat_dentry *ep;
148 struct buffer_head *bh;
149
150 ep = exfat_get_dentry(sb, p_dir: &clu, entry: i, bh: &bh);
151 if (!ep)
152 return -EIO;
153
154 type = exfat_get_entry_type(p_entry: ep);
155 if (type == TYPE_BITMAP &&
156 ep->dentry.bitmap.flags == 0x0) {
157 int err;
158
159 err = exfat_allocate_bitmap(sb, ep);
160 brelse(bh);
161 return err;
162 }
163 brelse(bh);
164
165 if (type == TYPE_UNUSED)
166 return -EINVAL;
167 }
168
169 if (exfat_get_next_cluster(sb, &clu.dir))
170 return -EIO;
171 }
172
173 return -EINVAL;
174}
175
176void exfat_free_bitmap(struct exfat_sb_info *sbi)
177{
178 int i;
179
180 for (i = 0; i < sbi->map_sectors; i++)
181 __brelse(sbi->vol_amap[i]);
182
183 kvfree(addr: sbi->vol_amap);
184}
185
186int exfat_set_bitmap(struct super_block *sb, unsigned int clu, bool sync)
187{
188 int i, b;
189 unsigned int ent_idx;
190 struct exfat_sb_info *sbi = EXFAT_SB(sb);
191
192 if (!is_valid_cluster(sbi, clus: clu))
193 return -EINVAL;
194
195 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
196 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
197 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
198
199 set_bit_le(nr: b, addr: sbi->vol_amap[i]->b_data);
200 exfat_update_bh(bh: sbi->vol_amap[i], sync);
201 return 0;
202}
203
204int exfat_clear_bitmap(struct super_block *sb, unsigned int clu, bool sync)
205{
206 int i, b;
207 unsigned int ent_idx;
208 struct exfat_sb_info *sbi = EXFAT_SB(sb);
209
210 if (!is_valid_cluster(sbi, clus: clu))
211 return -EIO;
212
213 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
214 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
215 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
216
217 if (!test_bit_le(nr: b, addr: sbi->vol_amap[i]->b_data))
218 return -EIO;
219
220 clear_bit_le(nr: b, addr: sbi->vol_amap[i]->b_data);
221
222 exfat_update_bh(bh: sbi->vol_amap[i], sync);
223
224 return 0;
225}
226
227bool exfat_test_bitmap(struct super_block *sb, unsigned int clu)
228{
229 int i, b;
230 unsigned int ent_idx;
231 struct exfat_sb_info *sbi = EXFAT_SB(sb);
232
233 if (!sbi->vol_amap)
234 return true;
235
236 if (!is_valid_cluster(sbi, clus: clu))
237 return false;
238
239 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
240 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
241 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
242
243 if (!test_bit_le(nr: b, addr: sbi->vol_amap[i]->b_data))
244 return false;
245
246 return true;
247}
248
249/*
250 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
251 * the cluster heap.
252 */
253unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
254{
255 unsigned int i, map_i, map_b, ent_idx;
256 unsigned int clu_base, clu_free;
257 unsigned long clu_bits, clu_mask;
258 struct exfat_sb_info *sbi = EXFAT_SB(sb);
259 __le_long bitval;
260
261 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
262 ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
263 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
264 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
265
266 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
267 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
268
269 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
270 i += BITS_PER_LONG) {
271 bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
272 if (clu_mask > 0) {
273 bitval |= cpu_to_lel(clu_mask);
274 clu_mask = 0;
275 }
276 if (lel_to_cpu(bitval) != ULONG_MAX) {
277 clu_bits = lel_to_cpu(bitval);
278 clu_free = clu_base + ffz(clu_bits);
279 if (clu_free < sbi->num_clusters)
280 return clu_free;
281 }
282 clu_base += BITS_PER_LONG;
283 map_b += sizeof(long);
284
285 if (map_b >= sb->s_blocksize ||
286 clu_base >= sbi->num_clusters) {
287 if (++map_i >= sbi->map_sectors) {
288 clu_base = EXFAT_FIRST_CLUSTER;
289 map_i = 0;
290 }
291 map_b = 0;
292 }
293 }
294
295 return EXFAT_EOF_CLUSTER;
296}
297
298int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
299{
300 struct exfat_sb_info *sbi = EXFAT_SB(sb);
301 unsigned int count = 0;
302 unsigned int i, map_i = 0, map_b = 0;
303 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
304 unsigned int last_mask = total_clus & (BITS_PER_LONG - 1);
305 unsigned long *bitmap, clu_bits;
306
307 total_clus &= ~last_mask;
308 for (i = 0; i < total_clus; i += BITS_PER_LONG) {
309 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
310 count += hweight_long(w: *bitmap);
311 map_b += sizeof(long);
312 if (map_b >= (unsigned int)sb->s_blocksize) {
313 map_i++;
314 map_b = 0;
315 }
316 }
317
318 if (last_mask) {
319 bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
320 clu_bits = lel_to_cpu(*(__le_long *)bitmap);
321 count += hweight_long(w: clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
322 }
323
324 *ret_count = count;
325 return 0;
326}
327
328int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
329{
330 unsigned int trim_begin, trim_end, count, next_free_clu;
331 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
332 struct super_block *sb = inode->i_sb;
333 struct exfat_sb_info *sbi = EXFAT_SB(sb);
334 int err = 0;
335
336 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
337 EXFAT_FIRST_CLUSTER);
338 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
339 trim_minlen = range->minlen >> sbi->cluster_size_bits;
340
341 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
342 return -EINVAL;
343
344 if (clu_end >= sbi->num_clusters)
345 clu_end = sbi->num_clusters - 1;
346
347 mutex_lock(&sbi->bitmap_lock);
348
349 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu: clu_start);
350 if (trim_begin == EXFAT_EOF_CLUSTER)
351 goto unlock;
352
353 next_free_clu = exfat_find_free_bitmap(sb, clu: trim_end + 1);
354 if (next_free_clu == EXFAT_EOF_CLUSTER)
355 goto unlock;
356
357 do {
358 if (next_free_clu == trim_end + 1) {
359 /* extend trim range for continuous free cluster */
360 trim_end++;
361 } else {
362 /* trim current range if it's larger than trim_minlen */
363 count = trim_end - trim_begin + 1;
364 if (count >= trim_minlen) {
365 err = sb_issue_discard(sb,
366 block: exfat_cluster_to_sector(sbi, clus: trim_begin),
367 nr_blocks: count * sbi->sect_per_clus, GFP_NOFS, flags: 0);
368 if (err)
369 goto unlock;
370
371 trimmed_total += count;
372 }
373
374 /* set next start point of the free hole */
375 trim_begin = trim_end = next_free_clu;
376 }
377
378 if (next_free_clu >= clu_end)
379 break;
380
381 if (fatal_signal_pending(current)) {
382 err = -ERESTARTSYS;
383 goto unlock;
384 }
385
386 next_free_clu = exfat_find_free_bitmap(sb, clu: next_free_clu + 1);
387 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
388 next_free_clu > trim_end);
389
390 /* try to trim remainder */
391 count = trim_end - trim_begin + 1;
392 if (count >= trim_minlen) {
393 err = sb_issue_discard(sb, block: exfat_cluster_to_sector(sbi, clus: trim_begin),
394 nr_blocks: count * sbi->sect_per_clus, GFP_NOFS, flags: 0);
395 if (err)
396 goto unlock;
397
398 trimmed_total += count;
399 }
400
401unlock:
402 mutex_unlock(lock: &sbi->bitmap_lock);
403 range->len = trimmed_total << sbi->cluster_size_bits;
404
405 return err;
406}
407

source code of linux/fs/exfat/balloc.c