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_ratelimit(sb, 93 "invalid access to FAT (entry 0x%08x)", 94 loc); 95 return -EIO; 96 } 97 98 err = __exfat_ent_get(sb, loc, content); 99 if (err) { 100 exfat_fs_error_ratelimit(sb, 101 "failed to access to FAT (entry 0x%08x, err:%d)", 102 loc, err); 103 return err; 104 } 105 106 if (*content == EXFAT_FREE_CLUSTER) { 107 exfat_fs_error_ratelimit(sb, 108 "invalid access to FAT free cluster (entry 0x%08x)", 109 loc); 110 return -EIO; 111 } 112 113 if (*content == EXFAT_BAD_CLUSTER) { 114 exfat_fs_error_ratelimit(sb, 115 "invalid access to FAT bad cluster (entry 0x%08x)", 116 loc); 117 return -EIO; 118 } 119 120 if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) { 121 exfat_fs_error_ratelimit(sb, 122 "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)", 123 loc, *content); 124 return -EIO; 125 } 126 127 return 0; 128 } 129 130 int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain, 131 unsigned int len) 132 { 133 if (!len) 134 return 0; 135 136 while (len > 1) { 137 if (exfat_ent_set(sb, chain, chain + 1)) 138 return -EIO; 139 chain++; 140 len--; 141 } 142 143 if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER)) 144 return -EIO; 145 return 0; 146 } 147 148 static inline void exfat_discard_cluster(struct super_block *sb, 149 unsigned int clu, unsigned int num_clusters) 150 { 151 int ret; 152 struct exfat_sb_info *sbi = EXFAT_SB(sb); 153 154 ret = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, clu), 155 sbi->sect_per_clus * num_clusters, GFP_NOFS, 0); 156 if (ret == -EOPNOTSUPP) { 157 exfat_err(sb, "discard not supported by device, disabling"); 158 sbi->options.discard = 0; 159 } 160 } 161 162 /* This function must be called with bitmap_lock held */ 163 static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 164 { 165 struct super_block *sb = inode->i_sb; 166 struct exfat_sb_info *sbi = EXFAT_SB(sb); 167 int cur_cmap_i, next_cmap_i; 168 unsigned int num_clusters = 0; 169 unsigned int clu; 170 171 /* invalid cluster number */ 172 if (p_chain->dir == EXFAT_FREE_CLUSTER || 173 p_chain->dir == EXFAT_EOF_CLUSTER || 174 p_chain->dir < EXFAT_FIRST_CLUSTER) 175 return 0; 176 177 /* no cluster to truncate */ 178 if (p_chain->size == 0) 179 return 0; 180 181 /* check cluster validation */ 182 if (!is_valid_cluster(sbi, p_chain->dir)) { 183 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir); 184 return -EIO; 185 } 186 187 clu = p_chain->dir; 188 189 cur_cmap_i = next_cmap_i = 190 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu)); 191 192 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 193 int err; 194 unsigned int last_cluster = p_chain->dir + p_chain->size - 1; 195 do { 196 bool sync = false; 197 198 if (clu < last_cluster) 199 next_cmap_i = 200 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1)); 201 202 /* flush bitmap only if index would be changed or for last cluster */ 203 if (clu == last_cluster || cur_cmap_i != next_cmap_i) { 204 sync = true; 205 cur_cmap_i = next_cmap_i; 206 } 207 208 err = exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))); 209 if (err) 210 break; 211 clu++; 212 num_clusters++; 213 } while (num_clusters < p_chain->size); 214 215 if (sbi->options.discard) 216 exfat_discard_cluster(sb, p_chain->dir, p_chain->size); 217 } else { 218 unsigned int nr_clu = 1; 219 220 do { 221 bool sync = false; 222 unsigned int n_clu = clu; 223 int err = exfat_get_next_cluster(sb, &n_clu); 224 225 if (err || n_clu == EXFAT_EOF_CLUSTER) 226 sync = true; 227 else 228 next_cmap_i = 229 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu)); 230 231 if (cur_cmap_i != next_cmap_i) { 232 sync = true; 233 cur_cmap_i = next_cmap_i; 234 } 235 236 if (exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)))) 237 break; 238 239 if (sbi->options.discard) { 240 if (n_clu == clu + 1) 241 nr_clu++; 242 else { 243 exfat_discard_cluster(sb, clu - nr_clu + 1, nr_clu); 244 nr_clu = 1; 245 } 246 } 247 248 clu = n_clu; 249 num_clusters++; 250 251 if (err) 252 break; 253 254 if (num_clusters >= sbi->num_clusters - EXFAT_FIRST_CLUSTER) { 255 /* 256 * The cluster chain includes a loop, scan the 257 * bitmap to get the number of used clusters. 258 */ 259 exfat_count_used_clusters(sb, &sbi->used_clusters); 260 261 return 0; 262 } 263 } while (clu != EXFAT_EOF_CLUSTER); 264 } 265 266 sbi->used_clusters -= num_clusters; 267 return 0; 268 } 269 270 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 271 { 272 int ret = 0; 273 274 mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock); 275 ret = __exfat_free_cluster(inode, p_chain); 276 mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock); 277 278 return ret; 279 } 280 281 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, 282 unsigned int *ret_clu) 283 { 284 unsigned int clu, next; 285 unsigned int count = 0; 286 287 next = p_chain->dir; 288 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 289 *ret_clu = next + p_chain->size - 1; 290 return 0; 291 } 292 293 do { 294 count++; 295 clu = next; 296 if (exfat_ent_get(sb, clu, &next)) 297 return -EIO; 298 } while (next != EXFAT_EOF_CLUSTER && count <= p_chain->size); 299 300 if (p_chain->size != count) { 301 exfat_fs_error(sb, 302 "bogus directory size (clus : ondisk(%d) != counted(%d))", 303 p_chain->size, count); 304 return -EIO; 305 } 306 307 *ret_clu = clu; 308 return 0; 309 } 310 311 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) 312 { 313 struct super_block *sb = dir->i_sb; 314 struct exfat_sb_info *sbi = EXFAT_SB(sb); 315 struct buffer_head *bh; 316 sector_t blknr, last_blknr, i; 317 318 blknr = exfat_cluster_to_sector(sbi, clu); 319 last_blknr = blknr + sbi->sect_per_clus; 320 321 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { 322 exfat_fs_error_ratelimit(sb, 323 "%s: out of range(sect:%llu len:%u)", 324 __func__, (unsigned long long)blknr, 325 sbi->sect_per_clus); 326 return -EIO; 327 } 328 329 /* Zeroing the unused blocks on this cluster */ 330 for (i = blknr; i < last_blknr; i++) { 331 bh = sb_getblk(sb, i); 332 if (!bh) 333 return -ENOMEM; 334 335 memset(bh->b_data, 0, sb->s_blocksize); 336 set_buffer_uptodate(bh); 337 mark_buffer_dirty(bh); 338 brelse(bh); 339 } 340 341 if (IS_DIRSYNC(dir)) 342 return sync_blockdev_range(sb->s_bdev, 343 EXFAT_BLK_TO_B(blknr, sb), 344 EXFAT_BLK_TO_B(last_blknr, sb) - 1); 345 346 return 0; 347 } 348 349 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, 350 struct exfat_chain *p_chain, bool sync_bmap) 351 { 352 int ret = -ENOSPC; 353 unsigned int total_cnt; 354 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; 355 struct super_block *sb = inode->i_sb; 356 struct exfat_sb_info *sbi = EXFAT_SB(sb); 357 358 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); 359 360 if (unlikely(total_cnt < sbi->used_clusters)) { 361 exfat_fs_error_ratelimit(sb, 362 "%s: invalid used clusters(t:%u,u:%u)\n", 363 __func__, total_cnt, sbi->used_clusters); 364 return -EIO; 365 } 366 367 if (num_alloc > total_cnt - sbi->used_clusters) 368 return -ENOSPC; 369 370 mutex_lock(&sbi->bitmap_lock); 371 372 hint_clu = p_chain->dir; 373 /* find new cluster */ 374 if (hint_clu == EXFAT_EOF_CLUSTER) { 375 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { 376 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)", 377 sbi->clu_srch_ptr); 378 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; 379 } 380 381 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); 382 if (hint_clu == EXFAT_EOF_CLUSTER) { 383 ret = -ENOSPC; 384 goto unlock; 385 } 386 } 387 388 /* check cluster validation */ 389 if (!is_valid_cluster(sbi, hint_clu)) { 390 if (hint_clu != sbi->num_clusters) 391 exfat_err(sb, "hint_cluster is invalid (%u), rewind to the first cluster", 392 hint_clu); 393 hint_clu = EXFAT_FIRST_CLUSTER; 394 p_chain->flags = ALLOC_FAT_CHAIN; 395 } 396 397 p_chain->dir = EXFAT_EOF_CLUSTER; 398 399 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != 400 EXFAT_EOF_CLUSTER) { 401 if (new_clu != hint_clu && 402 p_chain->flags == ALLOC_NO_FAT_CHAIN) { 403 if (exfat_chain_cont_cluster(sb, p_chain->dir, 404 p_chain->size)) { 405 ret = -EIO; 406 goto free_cluster; 407 } 408 p_chain->flags = ALLOC_FAT_CHAIN; 409 } 410 411 /* update allocation bitmap */ 412 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) { 413 ret = -EIO; 414 goto free_cluster; 415 } 416 417 /* update FAT table */ 418 if (p_chain->flags == ALLOC_FAT_CHAIN) { 419 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { 420 ret = -EIO; 421 goto free_cluster; 422 } 423 } 424 425 if (p_chain->dir == EXFAT_EOF_CLUSTER) { 426 p_chain->dir = new_clu; 427 } else if (p_chain->flags == ALLOC_FAT_CHAIN) { 428 if (exfat_ent_set(sb, last_clu, new_clu)) { 429 ret = -EIO; 430 goto free_cluster; 431 } 432 } 433 p_chain->size++; 434 435 last_clu = new_clu; 436 437 if (p_chain->size == num_alloc) { 438 sbi->clu_srch_ptr = hint_clu; 439 sbi->used_clusters += num_alloc; 440 441 mutex_unlock(&sbi->bitmap_lock); 442 return 0; 443 } 444 445 hint_clu = new_clu + 1; 446 if (hint_clu >= sbi->num_clusters) { 447 hint_clu = EXFAT_FIRST_CLUSTER; 448 449 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 450 if (exfat_chain_cont_cluster(sb, p_chain->dir, 451 p_chain->size)) { 452 ret = -EIO; 453 goto free_cluster; 454 } 455 p_chain->flags = ALLOC_FAT_CHAIN; 456 } 457 } 458 } 459 free_cluster: 460 __exfat_free_cluster(inode, p_chain); 461 unlock: 462 mutex_unlock(&sbi->bitmap_lock); 463 return ret; 464 } 465 466 int exfat_count_num_clusters(struct super_block *sb, 467 struct exfat_chain *p_chain, unsigned int *ret_count) 468 { 469 unsigned int i, count; 470 unsigned int clu; 471 struct exfat_sb_info *sbi = EXFAT_SB(sb); 472 473 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { 474 *ret_count = 0; 475 return 0; 476 } 477 478 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 479 *ret_count = p_chain->size; 480 return 0; 481 } 482 483 clu = p_chain->dir; 484 count = 0; 485 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { 486 count++; 487 if (exfat_ent_get(sb, clu, &clu)) 488 return -EIO; 489 if (clu == EXFAT_EOF_CLUSTER) 490 break; 491 } 492 493 *ret_count = count; 494 495 /* 496 * since exfat_count_used_clusters() is not called, sbi->used_clusters 497 * cannot be used here. 498 */ 499 if (unlikely(i == sbi->num_clusters && clu != EXFAT_EOF_CLUSTER)) { 500 exfat_fs_error(sb, "The cluster chain has a loop"); 501 return -EIO; 502 } 503 504 return 0; 505 } 506