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