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(sb, 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 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 155 { 156 unsigned int num_clusters = 0; 157 unsigned int clu; 158 struct super_block *sb = inode->i_sb; 159 struct exfat_sb_info *sbi = EXFAT_SB(sb); 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 set_bit(EXFAT_SB_DIRTY, &sbi->s_state); 178 clu = p_chain->dir; 179 180 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 181 do { 182 exfat_clear_bitmap(inode, clu); 183 clu++; 184 185 num_clusters++; 186 } while (num_clusters < p_chain->size); 187 } else { 188 do { 189 exfat_clear_bitmap(inode, clu); 190 191 if (exfat_get_next_cluster(sb, &clu)) 192 goto dec_used_clus; 193 194 num_clusters++; 195 } while (clu != EXFAT_EOF_CLUSTER); 196 } 197 198 dec_used_clus: 199 sbi->used_clusters -= num_clusters; 200 return 0; 201 } 202 203 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, 204 unsigned int *ret_clu) 205 { 206 unsigned int clu, next; 207 unsigned int count = 0; 208 209 next = p_chain->dir; 210 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 211 *ret_clu = next + p_chain->size - 1; 212 return 0; 213 } 214 215 do { 216 count++; 217 clu = next; 218 if (exfat_ent_get(sb, clu, &next)) 219 return -EIO; 220 } while (next != EXFAT_EOF_CLUSTER); 221 222 if (p_chain->size != count) { 223 exfat_fs_error(sb, 224 "bogus directory size (clus : ondisk(%d) != counted(%d))", 225 p_chain->size, count); 226 return -EIO; 227 } 228 229 *ret_clu = clu; 230 return 0; 231 } 232 233 static inline int exfat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 234 { 235 int i, err = 0; 236 237 for (i = 0; i < nr_bhs; i++) 238 write_dirty_buffer(bhs[i], 0); 239 240 for (i = 0; i < nr_bhs; i++) { 241 wait_on_buffer(bhs[i]); 242 if (!err && !buffer_uptodate(bhs[i])) 243 err = -EIO; 244 } 245 return err; 246 } 247 248 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) 249 { 250 struct super_block *sb = dir->i_sb; 251 struct exfat_sb_info *sbi = EXFAT_SB(sb); 252 struct buffer_head *bhs[MAX_BUF_PER_PAGE]; 253 int nr_bhs = MAX_BUF_PER_PAGE; 254 sector_t blknr, last_blknr; 255 int err, i, n; 256 257 blknr = exfat_cluster_to_sector(sbi, clu); 258 last_blknr = blknr + sbi->sect_per_clus; 259 260 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { 261 exfat_fs_error_ratelimit(sb, 262 "%s: out of range(sect:%llu len:%u)", 263 __func__, (unsigned long long)blknr, 264 sbi->sect_per_clus); 265 return -EIO; 266 } 267 268 /* Zeroing the unused blocks on this cluster */ 269 n = 0; 270 while (blknr < last_blknr) { 271 bhs[n] = sb_getblk(sb, blknr); 272 if (!bhs[n]) { 273 err = -ENOMEM; 274 goto release_bhs; 275 } 276 memset(bhs[n]->b_data, 0, sb->s_blocksize); 277 exfat_update_bh(sb, bhs[n], 0); 278 279 n++; 280 blknr++; 281 282 if (n == nr_bhs) { 283 if (IS_DIRSYNC(dir)) { 284 err = exfat_sync_bhs(bhs, n); 285 if (err) 286 goto release_bhs; 287 } 288 289 for (i = 0; i < n; i++) 290 brelse(bhs[i]); 291 n = 0; 292 } 293 } 294 295 if (IS_DIRSYNC(dir)) { 296 err = exfat_sync_bhs(bhs, n); 297 if (err) 298 goto release_bhs; 299 } 300 301 for (i = 0; i < n; i++) 302 brelse(bhs[i]); 303 304 return 0; 305 306 release_bhs: 307 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr); 308 for (i = 0; i < n; i++) 309 bforget(bhs[i]); 310 return err; 311 } 312 313 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, 314 struct exfat_chain *p_chain) 315 { 316 int ret = -ENOSPC; 317 unsigned int num_clusters = 0, total_cnt; 318 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; 319 struct super_block *sb = inode->i_sb; 320 struct exfat_sb_info *sbi = EXFAT_SB(sb); 321 322 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); 323 324 if (unlikely(total_cnt < sbi->used_clusters)) { 325 exfat_fs_error_ratelimit(sb, 326 "%s: invalid used clusters(t:%u,u:%u)\n", 327 __func__, total_cnt, sbi->used_clusters); 328 return -EIO; 329 } 330 331 if (num_alloc > total_cnt - sbi->used_clusters) 332 return -ENOSPC; 333 334 hint_clu = p_chain->dir; 335 /* find new cluster */ 336 if (hint_clu == EXFAT_EOF_CLUSTER) { 337 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { 338 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n", 339 sbi->clu_srch_ptr); 340 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; 341 } 342 343 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); 344 if (hint_clu == EXFAT_EOF_CLUSTER) 345 return -ENOSPC; 346 } 347 348 /* check cluster validation */ 349 if (!is_valid_cluster(sbi, hint_clu)) { 350 exfat_err(sb, "hint_cluster is invalid (%u)", 351 hint_clu); 352 hint_clu = EXFAT_FIRST_CLUSTER; 353 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 354 if (exfat_chain_cont_cluster(sb, p_chain->dir, 355 num_clusters)) 356 return -EIO; 357 p_chain->flags = ALLOC_FAT_CHAIN; 358 } 359 } 360 361 set_bit(EXFAT_SB_DIRTY, &sbi->s_state); 362 363 p_chain->dir = EXFAT_EOF_CLUSTER; 364 365 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != 366 EXFAT_EOF_CLUSTER) { 367 if (new_clu != hint_clu && 368 p_chain->flags == ALLOC_NO_FAT_CHAIN) { 369 if (exfat_chain_cont_cluster(sb, p_chain->dir, 370 num_clusters)) { 371 ret = -EIO; 372 goto free_cluster; 373 } 374 p_chain->flags = ALLOC_FAT_CHAIN; 375 } 376 377 /* update allocation bitmap */ 378 if (exfat_set_bitmap(inode, new_clu)) { 379 ret = -EIO; 380 goto free_cluster; 381 } 382 383 num_clusters++; 384 385 /* update FAT table */ 386 if (p_chain->flags == ALLOC_FAT_CHAIN) { 387 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { 388 ret = -EIO; 389 goto free_cluster; 390 } 391 } 392 393 if (p_chain->dir == EXFAT_EOF_CLUSTER) { 394 p_chain->dir = new_clu; 395 } else if (p_chain->flags == ALLOC_FAT_CHAIN) { 396 if (exfat_ent_set(sb, last_clu, new_clu)) { 397 ret = -EIO; 398 goto free_cluster; 399 } 400 } 401 last_clu = new_clu; 402 403 if (--num_alloc == 0) { 404 sbi->clu_srch_ptr = hint_clu; 405 sbi->used_clusters += num_clusters; 406 407 p_chain->size += num_clusters; 408 return 0; 409 } 410 411 hint_clu = new_clu + 1; 412 if (hint_clu >= sbi->num_clusters) { 413 hint_clu = EXFAT_FIRST_CLUSTER; 414 415 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 416 if (exfat_chain_cont_cluster(sb, p_chain->dir, 417 num_clusters)) { 418 ret = -EIO; 419 goto free_cluster; 420 } 421 p_chain->flags = ALLOC_FAT_CHAIN; 422 } 423 } 424 } 425 free_cluster: 426 if (num_clusters) 427 exfat_free_cluster(inode, p_chain); 428 return ret; 429 } 430 431 int exfat_count_num_clusters(struct super_block *sb, 432 struct exfat_chain *p_chain, unsigned int *ret_count) 433 { 434 unsigned int i, count; 435 unsigned int clu; 436 struct exfat_sb_info *sbi = EXFAT_SB(sb); 437 438 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { 439 *ret_count = 0; 440 return 0; 441 } 442 443 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 444 *ret_count = p_chain->size; 445 return 0; 446 } 447 448 clu = p_chain->dir; 449 count = 0; 450 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { 451 count++; 452 if (exfat_ent_get(sb, clu, &clu)) 453 return -EIO; 454 if (clu == EXFAT_EOF_CLUSTER) 455 break; 456 } 457 458 *ret_count = count; 459 return 0; 460 } 461