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 */ 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 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 } 130 131 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 } 168 169 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 } 178 179 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 } 196 197 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 } 219 220 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 */ 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 } 290 291 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 } 320 321 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