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 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 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 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 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 } 128 129 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 */ 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 unsigned int last_cluster = p_chain->dir + p_chain->size - 1; 179 do { 180 bool sync = false; 181 182 if (clu < last_cluster) 183 next_cmap_i = 184 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1)); 185 186 /* flush bitmap only if index would be changed or for last cluster */ 187 if (clu == last_cluster || cur_cmap_i != next_cmap_i) { 188 sync = true; 189 cur_cmap_i = next_cmap_i; 190 } 191 192 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))); 193 clu++; 194 num_clusters++; 195 } while (num_clusters < p_chain->size); 196 } else { 197 do { 198 bool sync = false; 199 unsigned int n_clu = clu; 200 int err = exfat_get_next_cluster(sb, &n_clu); 201 202 if (err || n_clu == EXFAT_EOF_CLUSTER) 203 sync = true; 204 else 205 next_cmap_i = 206 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu)); 207 208 if (cur_cmap_i != next_cmap_i) { 209 sync = true; 210 cur_cmap_i = next_cmap_i; 211 } 212 213 exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))); 214 clu = n_clu; 215 num_clusters++; 216 217 if (err) 218 goto dec_used_clus; 219 } while (clu != EXFAT_EOF_CLUSTER); 220 } 221 222 dec_used_clus: 223 sbi->used_clusters -= num_clusters; 224 return 0; 225 } 226 227 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 228 { 229 int ret = 0; 230 231 mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock); 232 ret = __exfat_free_cluster(inode, p_chain); 233 mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock); 234 235 return ret; 236 } 237 238 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, 239 unsigned int *ret_clu) 240 { 241 unsigned int clu, next; 242 unsigned int count = 0; 243 244 next = p_chain->dir; 245 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 246 *ret_clu = next + p_chain->size - 1; 247 return 0; 248 } 249 250 do { 251 count++; 252 clu = next; 253 if (exfat_ent_get(sb, clu, &next)) 254 return -EIO; 255 } while (next != EXFAT_EOF_CLUSTER); 256 257 if (p_chain->size != count) { 258 exfat_fs_error(sb, 259 "bogus directory size (clus : ondisk(%d) != counted(%d))", 260 p_chain->size, count); 261 return -EIO; 262 } 263 264 *ret_clu = clu; 265 return 0; 266 } 267 268 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) 269 { 270 struct super_block *sb = dir->i_sb; 271 struct exfat_sb_info *sbi = EXFAT_SB(sb); 272 struct buffer_head *bh; 273 sector_t blknr, last_blknr, i; 274 275 blknr = exfat_cluster_to_sector(sbi, clu); 276 last_blknr = blknr + sbi->sect_per_clus; 277 278 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { 279 exfat_fs_error_ratelimit(sb, 280 "%s: out of range(sect:%llu len:%u)", 281 __func__, (unsigned long long)blknr, 282 sbi->sect_per_clus); 283 return -EIO; 284 } 285 286 /* Zeroing the unused blocks on this cluster */ 287 for (i = blknr; i < last_blknr; i++) { 288 bh = sb_getblk(sb, i); 289 if (!bh) 290 return -ENOMEM; 291 292 memset(bh->b_data, 0, sb->s_blocksize); 293 set_buffer_uptodate(bh); 294 mark_buffer_dirty(bh); 295 brelse(bh); 296 } 297 298 if (IS_DIRSYNC(dir)) 299 return sync_blockdev_range(sb->s_bdev, 300 EXFAT_BLK_TO_B(blknr, sb), 301 EXFAT_BLK_TO_B(last_blknr, sb) - 1); 302 303 return 0; 304 } 305 306 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, 307 struct exfat_chain *p_chain, bool sync_bmap) 308 { 309 int ret = -ENOSPC; 310 unsigned int total_cnt; 311 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; 312 struct super_block *sb = inode->i_sb; 313 struct exfat_sb_info *sbi = EXFAT_SB(sb); 314 315 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); 316 317 if (unlikely(total_cnt < sbi->used_clusters)) { 318 exfat_fs_error_ratelimit(sb, 319 "%s: invalid used clusters(t:%u,u:%u)\n", 320 __func__, total_cnt, sbi->used_clusters); 321 return -EIO; 322 } 323 324 if (num_alloc > total_cnt - sbi->used_clusters) 325 return -ENOSPC; 326 327 mutex_lock(&sbi->bitmap_lock); 328 329 hint_clu = p_chain->dir; 330 /* find new cluster */ 331 if (hint_clu == EXFAT_EOF_CLUSTER) { 332 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { 333 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)", 334 sbi->clu_srch_ptr); 335 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; 336 } 337 338 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); 339 if (hint_clu == EXFAT_EOF_CLUSTER) { 340 ret = -ENOSPC; 341 goto unlock; 342 } 343 } 344 345 /* check cluster validation */ 346 if (!is_valid_cluster(sbi, hint_clu)) { 347 if (hint_clu != sbi->num_clusters) 348 exfat_err(sb, "hint_cluster is invalid (%u), rewind to the first cluster", 349 hint_clu); 350 hint_clu = EXFAT_FIRST_CLUSTER; 351 p_chain->flags = ALLOC_FAT_CHAIN; 352 } 353 354 p_chain->dir = EXFAT_EOF_CLUSTER; 355 356 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != 357 EXFAT_EOF_CLUSTER) { 358 if (new_clu != hint_clu && 359 p_chain->flags == ALLOC_NO_FAT_CHAIN) { 360 if (exfat_chain_cont_cluster(sb, p_chain->dir, 361 p_chain->size)) { 362 ret = -EIO; 363 goto free_cluster; 364 } 365 p_chain->flags = ALLOC_FAT_CHAIN; 366 } 367 368 /* update allocation bitmap */ 369 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) { 370 ret = -EIO; 371 goto free_cluster; 372 } 373 374 /* update FAT table */ 375 if (p_chain->flags == ALLOC_FAT_CHAIN) { 376 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { 377 ret = -EIO; 378 goto free_cluster; 379 } 380 } 381 382 if (p_chain->dir == EXFAT_EOF_CLUSTER) { 383 p_chain->dir = new_clu; 384 } else if (p_chain->flags == ALLOC_FAT_CHAIN) { 385 if (exfat_ent_set(sb, last_clu, new_clu)) { 386 ret = -EIO; 387 goto free_cluster; 388 } 389 } 390 p_chain->size++; 391 392 last_clu = new_clu; 393 394 if (p_chain->size == num_alloc) { 395 sbi->clu_srch_ptr = hint_clu; 396 sbi->used_clusters += num_alloc; 397 398 mutex_unlock(&sbi->bitmap_lock); 399 return 0; 400 } 401 402 hint_clu = new_clu + 1; 403 if (hint_clu >= sbi->num_clusters) { 404 hint_clu = EXFAT_FIRST_CLUSTER; 405 406 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 407 if (exfat_chain_cont_cluster(sb, p_chain->dir, 408 p_chain->size)) { 409 ret = -EIO; 410 goto free_cluster; 411 } 412 p_chain->flags = ALLOC_FAT_CHAIN; 413 } 414 } 415 } 416 free_cluster: 417 __exfat_free_cluster(inode, p_chain); 418 unlock: 419 mutex_unlock(&sbi->bitmap_lock); 420 return ret; 421 } 422 423 int exfat_count_num_clusters(struct super_block *sb, 424 struct exfat_chain *p_chain, unsigned int *ret_count) 425 { 426 unsigned int i, count; 427 unsigned int clu; 428 struct exfat_sb_info *sbi = EXFAT_SB(sb); 429 430 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { 431 *ret_count = 0; 432 return 0; 433 } 434 435 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 436 *ret_count = p_chain->size; 437 return 0; 438 } 439 440 clu = p_chain->dir; 441 count = 0; 442 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { 443 count++; 444 if (exfat_ent_get(sb, clu, &clu)) 445 return -EIO; 446 if (clu == EXFAT_EOF_CLUSTER) 447 break; 448 } 449 450 *ret_count = count; 451 return 0; 452 } 453