1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. 4 */ 5 6 #include <linux/slab.h> 7 #include <linux/unaligned.h> 8 #include <linux/buffer_head.h> 9 #include <linux/blkdev.h> 10 11 #include "exfat_raw.h" 12 #include "exfat_fs.h" 13 14 static int exfat_mirror_bh(struct super_block *sb, sector_t sec, 15 struct buffer_head *bh) 16 { 17 struct buffer_head *c_bh; 18 struct exfat_sb_info *sbi = EXFAT_SB(sb); 19 sector_t sec2; 20 int err = 0; 21 22 if (sbi->FAT2_start_sector != sbi->FAT1_start_sector) { 23 sec2 = sec - sbi->FAT1_start_sector + sbi->FAT2_start_sector; 24 c_bh = sb_getblk(sb, sec2); 25 if (!c_bh) 26 return -ENOMEM; 27 memcpy(c_bh->b_data, bh->b_data, sb->s_blocksize); 28 set_buffer_uptodate(c_bh); 29 mark_buffer_dirty(c_bh); 30 if (sb->s_flags & SB_SYNCHRONOUS) 31 err = sync_dirty_buffer(c_bh); 32 brelse(c_bh); 33 } 34 35 return err; 36 } 37 38 static int __exfat_ent_get(struct super_block *sb, unsigned int loc, 39 unsigned int *content) 40 { 41 unsigned int off; 42 sector_t sec; 43 struct buffer_head *bh; 44 45 sec = FAT_ENT_OFFSET_SECTOR(sb, loc); 46 off = FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc); 47 48 bh = sb_bread(sb, sec); 49 if (!bh) 50 return -EIO; 51 52 *content = le32_to_cpu(*(__le32 *)(&bh->b_data[off])); 53 54 /* remap reserved clusters to simplify code */ 55 if (*content > EXFAT_BAD_CLUSTER) 56 *content = EXFAT_EOF_CLUSTER; 57 58 brelse(bh); 59 return 0; 60 } 61 62 int exfat_ent_set(struct super_block *sb, unsigned int loc, 63 unsigned int content) 64 { 65 unsigned int off; 66 sector_t sec; 67 __le32 *fat_entry; 68 struct buffer_head *bh; 69 70 sec = FAT_ENT_OFFSET_SECTOR(sb, loc); 71 off = FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc); 72 73 bh = sb_bread(sb, sec); 74 if (!bh) 75 return -EIO; 76 77 fat_entry = (__le32 *)&(bh->b_data[off]); 78 *fat_entry = cpu_to_le32(content); 79 exfat_update_bh(bh, sb->s_flags & SB_SYNCHRONOUS); 80 exfat_mirror_bh(sb, sec, bh); 81 brelse(bh); 82 return 0; 83 } 84 85 int exfat_ent_get(struct super_block *sb, unsigned int loc, 86 unsigned int *content) 87 { 88 struct exfat_sb_info *sbi = EXFAT_SB(sb); 89 int err; 90 91 if (!is_valid_cluster(sbi, loc)) { 92 exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", 93 loc); 94 return -EIO; 95 } 96 97 err = __exfat_ent_get(sb, loc, content); 98 if (err) { 99 exfat_fs_error(sb, 100 "failed to access to FAT (entry 0x%08x, err:%d)", 101 loc, err); 102 return err; 103 } 104 105 if (*content == EXFAT_FREE_CLUSTER) { 106 exfat_fs_error(sb, 107 "invalid access to FAT free cluster (entry 0x%08x)", 108 loc); 109 return -EIO; 110 } 111 112 if (*content == EXFAT_BAD_CLUSTER) { 113 exfat_fs_error(sb, 114 "invalid access to FAT bad cluster (entry 0x%08x)", 115 loc); 116 return -EIO; 117 } 118 119 if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) { 120 exfat_fs_error(sb, 121 "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)", 122 loc, *content); 123 return -EIO; 124 } 125 126 return 0; 127 } 128 129 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain, 130 unsigned int len) 131 { 132 if (!len) 133 return 0; 134 135 while (len > 1) { 136 if (exfat_ent_set(sb, chain, chain + 1)) 137 return -EIO; 138 chain++; 139 len--; 140 } 141 142 if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER)) 143 return -EIO; 144 return 0; 145 } 146 147 static inline void exfat_discard_cluster(struct super_block *sb, 148 unsigned int clu, unsigned int num_clusters) 149 { 150 int ret; 151 struct exfat_sb_info *sbi = EXFAT_SB(sb); 152 153 ret = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, clu), 154 sbi->sect_per_clus * num_clusters, GFP_NOFS, 0); 155 if (ret == -EOPNOTSUPP) { 156 exfat_err(sb, "discard not supported by device, disabling"); 157 sbi->options.discard = 0; 158 } 159 } 160 161 /* This function must be called with bitmap_lock held */ 162 static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 163 { 164 struct super_block *sb = inode->i_sb; 165 struct exfat_sb_info *sbi = EXFAT_SB(sb); 166 int cur_cmap_i, next_cmap_i; 167 unsigned int num_clusters = 0; 168 unsigned int clu; 169 170 /* invalid cluster number */ 171 if (p_chain->dir == EXFAT_FREE_CLUSTER || 172 p_chain->dir == EXFAT_EOF_CLUSTER || 173 p_chain->dir < EXFAT_FIRST_CLUSTER) 174 return 0; 175 176 /* no cluster to truncate */ 177 if (p_chain->size == 0) 178 return 0; 179 180 /* check cluster validation */ 181 if (!is_valid_cluster(sbi, p_chain->dir)) { 182 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir); 183 return -EIO; 184 } 185 186 clu = p_chain->dir; 187 188 cur_cmap_i = next_cmap_i = 189 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu)); 190 191 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 192 int err; 193 unsigned int last_cluster = p_chain->dir + p_chain->size - 1; 194 do { 195 bool sync = false; 196 197 if (clu < last_cluster) 198 next_cmap_i = 199 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1)); 200 201 /* flush bitmap only if index would be changed or for last cluster */ 202 if (clu == last_cluster || cur_cmap_i != next_cmap_i) { 203 sync = true; 204 cur_cmap_i = next_cmap_i; 205 } 206 207 err = exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))); 208 if (err) 209 break; 210 clu++; 211 num_clusters++; 212 } while (num_clusters < p_chain->size); 213 214 if (sbi->options.discard) 215 exfat_discard_cluster(sb, p_chain->dir, p_chain->size); 216 } else { 217 unsigned int nr_clu = 1; 218 219 do { 220 bool sync = false; 221 unsigned int n_clu = clu; 222 int err = exfat_get_next_cluster(sb, &n_clu); 223 224 if (err || n_clu == EXFAT_EOF_CLUSTER) 225 sync = true; 226 else 227 next_cmap_i = 228 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu)); 229 230 if (cur_cmap_i != next_cmap_i) { 231 sync = true; 232 cur_cmap_i = next_cmap_i; 233 } 234 235 if (exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)))) 236 break; 237 238 if (sbi->options.discard) { 239 if (n_clu == clu + 1) 240 nr_clu++; 241 else { 242 exfat_discard_cluster(sb, clu - nr_clu + 1, nr_clu); 243 nr_clu = 1; 244 } 245 } 246 247 clu = n_clu; 248 num_clusters++; 249 250 if (err) 251 break; 252 253 if (num_clusters >= sbi->num_clusters - EXFAT_FIRST_CLUSTER) { 254 /* 255 * The cluster chain includes a loop, scan the 256 * bitmap to get the number of used clusters. 257 */ 258 exfat_count_used_clusters(sb, &sbi->used_clusters); 259 260 return 0; 261 } 262 } while (clu != EXFAT_EOF_CLUSTER); 263 } 264 265 sbi->used_clusters -= num_clusters; 266 return 0; 267 } 268 269 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 270 { 271 int ret = 0; 272 273 mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock); 274 ret = __exfat_free_cluster(inode, p_chain); 275 mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock); 276 277 return ret; 278 } 279 280 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, 281 unsigned int *ret_clu) 282 { 283 unsigned int clu, next; 284 unsigned int count = 0; 285 286 next = p_chain->dir; 287 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 288 *ret_clu = next + p_chain->size - 1; 289 return 0; 290 } 291 292 do { 293 count++; 294 clu = next; 295 if (exfat_ent_get(sb, clu, &next)) 296 return -EIO; 297 } while (next != EXFAT_EOF_CLUSTER && count <= p_chain->size); 298 299 if (p_chain->size != count) { 300 exfat_fs_error(sb, 301 "bogus directory size (clus : ondisk(%d) != counted(%d))", 302 p_chain->size, count); 303 return -EIO; 304 } 305 306 *ret_clu = clu; 307 return 0; 308 } 309 310 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) 311 { 312 struct super_block *sb = dir->i_sb; 313 struct exfat_sb_info *sbi = EXFAT_SB(sb); 314 struct buffer_head *bh; 315 sector_t blknr, last_blknr, i; 316 317 blknr = exfat_cluster_to_sector(sbi, clu); 318 last_blknr = blknr + sbi->sect_per_clus; 319 320 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { 321 exfat_fs_error_ratelimit(sb, 322 "%s: out of range(sect:%llu len:%u)", 323 __func__, (unsigned long long)blknr, 324 sbi->sect_per_clus); 325 return -EIO; 326 } 327 328 /* Zeroing the unused blocks on this cluster */ 329 for (i = blknr; i < last_blknr; i++) { 330 bh = sb_getblk(sb, i); 331 if (!bh) 332 return -ENOMEM; 333 334 memset(bh->b_data, 0, sb->s_blocksize); 335 set_buffer_uptodate(bh); 336 mark_buffer_dirty(bh); 337 brelse(bh); 338 } 339 340 if (IS_DIRSYNC(dir)) 341 return sync_blockdev_range(sb->s_bdev, 342 EXFAT_BLK_TO_B(blknr, sb), 343 EXFAT_BLK_TO_B(last_blknr, sb) - 1); 344 345 return 0; 346 } 347 348 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, 349 struct exfat_chain *p_chain, bool sync_bmap) 350 { 351 int ret = -ENOSPC; 352 unsigned int total_cnt; 353 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; 354 struct super_block *sb = inode->i_sb; 355 struct exfat_sb_info *sbi = EXFAT_SB(sb); 356 357 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); 358 359 if (unlikely(total_cnt < sbi->used_clusters)) { 360 exfat_fs_error_ratelimit(sb, 361 "%s: invalid used clusters(t:%u,u:%u)\n", 362 __func__, total_cnt, sbi->used_clusters); 363 return -EIO; 364 } 365 366 if (num_alloc > total_cnt - sbi->used_clusters) 367 return -ENOSPC; 368 369 mutex_lock(&sbi->bitmap_lock); 370 371 hint_clu = p_chain->dir; 372 /* find new cluster */ 373 if (hint_clu == EXFAT_EOF_CLUSTER) { 374 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { 375 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)", 376 sbi->clu_srch_ptr); 377 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; 378 } 379 380 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); 381 if (hint_clu == EXFAT_EOF_CLUSTER) { 382 ret = -ENOSPC; 383 goto unlock; 384 } 385 } 386 387 /* check cluster validation */ 388 if (!is_valid_cluster(sbi, hint_clu)) { 389 if (hint_clu != sbi->num_clusters) 390 exfat_err(sb, "hint_cluster is invalid (%u), rewind to the first cluster", 391 hint_clu); 392 hint_clu = EXFAT_FIRST_CLUSTER; 393 p_chain->flags = ALLOC_FAT_CHAIN; 394 } 395 396 p_chain->dir = EXFAT_EOF_CLUSTER; 397 398 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != 399 EXFAT_EOF_CLUSTER) { 400 if (new_clu != hint_clu && 401 p_chain->flags == ALLOC_NO_FAT_CHAIN) { 402 if (exfat_chain_cont_cluster(sb, p_chain->dir, 403 p_chain->size)) { 404 ret = -EIO; 405 goto free_cluster; 406 } 407 p_chain->flags = ALLOC_FAT_CHAIN; 408 } 409 410 /* update allocation bitmap */ 411 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) { 412 ret = -EIO; 413 goto free_cluster; 414 } 415 416 /* update FAT table */ 417 if (p_chain->flags == ALLOC_FAT_CHAIN) { 418 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { 419 ret = -EIO; 420 goto free_cluster; 421 } 422 } 423 424 if (p_chain->dir == EXFAT_EOF_CLUSTER) { 425 p_chain->dir = new_clu; 426 } else if (p_chain->flags == ALLOC_FAT_CHAIN) { 427 if (exfat_ent_set(sb, last_clu, new_clu)) { 428 ret = -EIO; 429 goto free_cluster; 430 } 431 } 432 p_chain->size++; 433 434 last_clu = new_clu; 435 436 if (p_chain->size == num_alloc) { 437 sbi->clu_srch_ptr = hint_clu; 438 sbi->used_clusters += num_alloc; 439 440 mutex_unlock(&sbi->bitmap_lock); 441 return 0; 442 } 443 444 hint_clu = new_clu + 1; 445 if (hint_clu >= sbi->num_clusters) { 446 hint_clu = EXFAT_FIRST_CLUSTER; 447 448 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 449 if (exfat_chain_cont_cluster(sb, p_chain->dir, 450 p_chain->size)) { 451 ret = -EIO; 452 goto free_cluster; 453 } 454 p_chain->flags = ALLOC_FAT_CHAIN; 455 } 456 } 457 } 458 free_cluster: 459 __exfat_free_cluster(inode, p_chain); 460 unlock: 461 mutex_unlock(&sbi->bitmap_lock); 462 return ret; 463 } 464 465 int exfat_count_num_clusters(struct super_block *sb, 466 struct exfat_chain *p_chain, unsigned int *ret_count) 467 { 468 unsigned int i, count; 469 unsigned int clu; 470 struct exfat_sb_info *sbi = EXFAT_SB(sb); 471 472 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { 473 *ret_count = 0; 474 return 0; 475 } 476 477 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 478 *ret_count = p_chain->size; 479 return 0; 480 } 481 482 clu = p_chain->dir; 483 count = 0; 484 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { 485 count++; 486 if (exfat_ent_get(sb, clu, &clu)) 487 return -EIO; 488 if (clu == EXFAT_EOF_CLUSTER) 489 break; 490 } 491 492 *ret_count = count; 493 return 0; 494 } 495