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