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); 160 161 /* 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 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 180 do { 181 exfat_clear_bitmap(inode, clu); 182 clu++; 183 184 num_clusters++; 185 } while (num_clusters < p_chain->size); 186 } else { 187 do { 188 exfat_clear_bitmap(inode, clu); 189 190 if (exfat_get_next_cluster(sb, &clu)) 191 goto dec_used_clus; 192 193 num_clusters++; 194 } while (clu != EXFAT_EOF_CLUSTER); 195 } 196 197 dec_used_clus: 198 sbi->used_clusters -= num_clusters; 199 return 0; 200 } 201 202 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, 203 unsigned int *ret_clu) 204 { 205 unsigned int clu, next; 206 unsigned int count = 0; 207 208 next = p_chain->dir; 209 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 210 *ret_clu = next + p_chain->size - 1; 211 return 0; 212 } 213 214 do { 215 count++; 216 clu = next; 217 if (exfat_ent_get(sb, clu, &next)) 218 return -EIO; 219 } while (next != EXFAT_EOF_CLUSTER); 220 221 if (p_chain->size != count) { 222 exfat_fs_error(sb, 223 "bogus directory size (clus : ondisk(%d) != counted(%d))", 224 p_chain->size, count); 225 return -EIO; 226 } 227 228 *ret_clu = clu; 229 return 0; 230 } 231 232 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) 233 { 234 struct super_block *sb = dir->i_sb; 235 struct exfat_sb_info *sbi = EXFAT_SB(sb); 236 struct buffer_head *bhs[MAX_BUF_PER_PAGE]; 237 int nr_bhs = MAX_BUF_PER_PAGE; 238 sector_t blknr, last_blknr; 239 int err, i, n; 240 241 blknr = exfat_cluster_to_sector(sbi, clu); 242 last_blknr = blknr + sbi->sect_per_clus; 243 244 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { 245 exfat_fs_error_ratelimit(sb, 246 "%s: out of range(sect:%llu len:%u)", 247 __func__, (unsigned long long)blknr, 248 sbi->sect_per_clus); 249 return -EIO; 250 } 251 252 /* Zeroing the unused blocks on this cluster */ 253 while (blknr < last_blknr) { 254 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) { 255 bhs[n] = sb_getblk(sb, blknr); 256 if (!bhs[n]) { 257 err = -ENOMEM; 258 goto release_bhs; 259 } 260 memset(bhs[n]->b_data, 0, sb->s_blocksize); 261 } 262 263 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir)); 264 if (err) 265 goto release_bhs; 266 267 for (i = 0; i < n; i++) 268 brelse(bhs[i]); 269 } 270 return 0; 271 272 release_bhs: 273 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr); 274 for (i = 0; i < n; i++) 275 bforget(bhs[i]); 276 return err; 277 } 278 279 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, 280 struct exfat_chain *p_chain) 281 { 282 int ret = -ENOSPC; 283 unsigned int num_clusters = 0, total_cnt; 284 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; 285 struct super_block *sb = inode->i_sb; 286 struct exfat_sb_info *sbi = EXFAT_SB(sb); 287 288 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); 289 290 if (unlikely(total_cnt < sbi->used_clusters)) { 291 exfat_fs_error_ratelimit(sb, 292 "%s: invalid used clusters(t:%u,u:%u)\n", 293 __func__, total_cnt, sbi->used_clusters); 294 return -EIO; 295 } 296 297 if (num_alloc > total_cnt - sbi->used_clusters) 298 return -ENOSPC; 299 300 hint_clu = p_chain->dir; 301 /* find new cluster */ 302 if (hint_clu == EXFAT_EOF_CLUSTER) { 303 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { 304 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n", 305 sbi->clu_srch_ptr); 306 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; 307 } 308 309 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); 310 if (hint_clu == EXFAT_EOF_CLUSTER) 311 return -ENOSPC; 312 } 313 314 /* check cluster validation */ 315 if (!is_valid_cluster(sbi, hint_clu)) { 316 exfat_err(sb, "hint_cluster is invalid (%u)", 317 hint_clu); 318 hint_clu = EXFAT_FIRST_CLUSTER; 319 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 320 if (exfat_chain_cont_cluster(sb, p_chain->dir, 321 num_clusters)) 322 return -EIO; 323 p_chain->flags = ALLOC_FAT_CHAIN; 324 } 325 } 326 327 p_chain->dir = EXFAT_EOF_CLUSTER; 328 329 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != 330 EXFAT_EOF_CLUSTER) { 331 if (new_clu != hint_clu && 332 p_chain->flags == ALLOC_NO_FAT_CHAIN) { 333 if (exfat_chain_cont_cluster(sb, p_chain->dir, 334 num_clusters)) { 335 ret = -EIO; 336 goto free_cluster; 337 } 338 p_chain->flags = ALLOC_FAT_CHAIN; 339 } 340 341 /* update allocation bitmap */ 342 if (exfat_set_bitmap(inode, new_clu)) { 343 ret = -EIO; 344 goto free_cluster; 345 } 346 347 num_clusters++; 348 349 /* update FAT table */ 350 if (p_chain->flags == ALLOC_FAT_CHAIN) { 351 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { 352 ret = -EIO; 353 goto free_cluster; 354 } 355 } 356 357 if (p_chain->dir == EXFAT_EOF_CLUSTER) { 358 p_chain->dir = new_clu; 359 } else if (p_chain->flags == ALLOC_FAT_CHAIN) { 360 if (exfat_ent_set(sb, last_clu, new_clu)) { 361 ret = -EIO; 362 goto free_cluster; 363 } 364 } 365 last_clu = new_clu; 366 367 if (--num_alloc == 0) { 368 sbi->clu_srch_ptr = hint_clu; 369 sbi->used_clusters += num_clusters; 370 371 p_chain->size += num_clusters; 372 return 0; 373 } 374 375 hint_clu = new_clu + 1; 376 if (hint_clu >= sbi->num_clusters) { 377 hint_clu = EXFAT_FIRST_CLUSTER; 378 379 if (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 } 389 free_cluster: 390 if (num_clusters) 391 exfat_free_cluster(inode, p_chain); 392 return ret; 393 } 394 395 int exfat_count_num_clusters(struct super_block *sb, 396 struct exfat_chain *p_chain, unsigned int *ret_count) 397 { 398 unsigned int i, count; 399 unsigned int clu; 400 struct exfat_sb_info *sbi = EXFAT_SB(sb); 401 402 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { 403 *ret_count = 0; 404 return 0; 405 } 406 407 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 408 *ret_count = p_chain->size; 409 return 0; 410 } 411 412 clu = p_chain->dir; 413 count = 0; 414 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { 415 count++; 416 if (exfat_ent_get(sb, clu, &clu)) 417 return -EIO; 418 if (clu == EXFAT_EOF_CLUSTER) 419 break; 420 } 421 422 *ret_count = count; 423 return 0; 424 } 425