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