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