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 13static 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 37static 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 61int 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 84int exfat_ent_get(struct super_block *sb, unsigned int loc, 85 unsigned int *content) 86{ 87 struct exfat_sb_info *sbi = EXFAT_SB(sb); 88 int err; 89 90 if (!is_valid_cluster(sbi, loc)) { 91 exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", 92 loc); 93 return -EIO; 94 } 95 96 err = __exfat_ent_get(sb, loc, content); 97 if (err) { 98 exfat_fs_error(sb, 99 "failed to access to FAT (entry 0x%08x, err:%d)", 100 loc, err); 101 return err; 102 } 103 104 if (*content == EXFAT_FREE_CLUSTER) { 105 exfat_fs_error(sb, 106 "invalid access to FAT free cluster (entry 0x%08x)", 107 loc); 108 return -EIO; 109 } 110 111 if (*content == EXFAT_BAD_CLUSTER) { 112 exfat_fs_error(sb, 113 "invalid access to FAT bad cluster (entry 0x%08x)", 114 loc); 115 return -EIO; 116 } 117 118 if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) { 119 exfat_fs_error(sb, 120 "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)", 121 loc, *content); 122 return -EIO; 123 } 124 125 return 0; 126} 127 128int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain, 129 unsigned int len) 130{ 131 if (!len) 132 return 0; 133 134 while (len > 1) { 135 if (exfat_ent_set(sb, chain, chain + 1)) 136 return -EIO; 137 chain++; 138 len--; 139 } 140 141 if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER)) 142 return -EIO; 143 return 0; 144} 145 146int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) 147{ 148 unsigned int num_clusters = 0; 149 unsigned int clu; 150 struct super_block *sb = inode->i_sb; 151 struct exfat_sb_info *sbi = EXFAT_SB(sb); 152 153 /* invalid cluster number */ 154 if (p_chain->dir == EXFAT_FREE_CLUSTER || 155 p_chain->dir == EXFAT_EOF_CLUSTER || 156 p_chain->dir < EXFAT_FIRST_CLUSTER) 157 return 0; 158 159 /* no cluster to truncate */ 160 if (p_chain->size == 0) 161 return 0; 162 163 /* check cluster validation */ 164 if (!is_valid_cluster(sbi, p_chain->dir)) { 165 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir); 166 return -EIO; 167 } 168 169 clu = p_chain->dir; 170 171 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 172 do { 173 exfat_clear_bitmap(inode, clu); 174 clu++; 175 176 num_clusters++; 177 } while (num_clusters < p_chain->size); 178 } else { 179 do { 180 exfat_clear_bitmap(inode, clu); 181 182 if (exfat_get_next_cluster(sb, &clu)) 183 goto dec_used_clus; 184 185 num_clusters++; 186 } while (clu != EXFAT_EOF_CLUSTER); 187 } 188 189dec_used_clus: 190 sbi->used_clusters -= num_clusters; 191 return 0; 192} 193 194int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, 195 unsigned int *ret_clu) 196{ 197 unsigned int clu, next; 198 unsigned int count = 0; 199 200 next = p_chain->dir; 201 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 202 *ret_clu = next + p_chain->size - 1; 203 return 0; 204 } 205 206 do { 207 count++; 208 clu = next; 209 if (exfat_ent_get(sb, clu, &next)) 210 return -EIO; 211 } while (next != EXFAT_EOF_CLUSTER); 212 213 if (p_chain->size != count) { 214 exfat_fs_error(sb, 215 "bogus directory size (clus : ondisk(%d) != counted(%d))", 216 p_chain->size, count); 217 return -EIO; 218 } 219 220 *ret_clu = clu; 221 return 0; 222} 223 224int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) 225{ 226 struct super_block *sb = dir->i_sb; 227 struct exfat_sb_info *sbi = EXFAT_SB(sb); 228 struct buffer_head *bhs[MAX_BUF_PER_PAGE]; 229 int nr_bhs = MAX_BUF_PER_PAGE; 230 sector_t blknr, last_blknr; 231 int err, i, n; 232 233 blknr = exfat_cluster_to_sector(sbi, clu); 234 last_blknr = blknr + sbi->sect_per_clus; 235 236 if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { 237 exfat_fs_error_ratelimit(sb, 238 "%s: out of range(sect:%llu len:%u)", 239 __func__, (unsigned long long)blknr, 240 sbi->sect_per_clus); 241 return -EIO; 242 } 243 244 /* Zeroing the unused blocks on this cluster */ 245 while (blknr < last_blknr) { 246 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) { 247 bhs[n] = sb_getblk(sb, blknr); 248 if (!bhs[n]) { 249 err = -ENOMEM; 250 goto release_bhs; 251 } 252 memset(bhs[n]->b_data, 0, sb->s_blocksize); 253 } 254 255 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir)); 256 if (err) 257 goto release_bhs; 258 259 for (i = 0; i < n; i++) 260 brelse(bhs[i]); 261 } 262 return 0; 263 264release_bhs: 265 exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr); 266 for (i = 0; i < n; i++) 267 bforget(bhs[i]); 268 return err; 269} 270 271int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, 272 struct exfat_chain *p_chain) 273{ 274 int ret = -ENOSPC; 275 unsigned int num_clusters = 0, total_cnt; 276 unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; 277 struct super_block *sb = inode->i_sb; 278 struct exfat_sb_info *sbi = EXFAT_SB(sb); 279 280 total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); 281 282 if (unlikely(total_cnt < sbi->used_clusters)) { 283 exfat_fs_error_ratelimit(sb, 284 "%s: invalid used clusters(t:%u,u:%u)\n", 285 __func__, total_cnt, sbi->used_clusters); 286 return -EIO; 287 } 288 289 if (num_alloc > total_cnt - sbi->used_clusters) 290 return -ENOSPC; 291 292 hint_clu = p_chain->dir; 293 /* find new cluster */ 294 if (hint_clu == EXFAT_EOF_CLUSTER) { 295 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { 296 exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n", 297 sbi->clu_srch_ptr); 298 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; 299 } 300 301 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); 302 if (hint_clu == EXFAT_EOF_CLUSTER) 303 return -ENOSPC; 304 } 305 306 /* check cluster validation */ 307 if (!is_valid_cluster(sbi, hint_clu)) { 308 exfat_err(sb, "hint_cluster is invalid (%u)", 309 hint_clu); 310 hint_clu = EXFAT_FIRST_CLUSTER; 311 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 312 if (exfat_chain_cont_cluster(sb, p_chain->dir, 313 num_clusters)) 314 return -EIO; 315 p_chain->flags = ALLOC_FAT_CHAIN; 316 } 317 } 318 319 p_chain->dir = EXFAT_EOF_CLUSTER; 320 321 while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != 322 EXFAT_EOF_CLUSTER) { 323 if (new_clu != hint_clu && 324 p_chain->flags == ALLOC_NO_FAT_CHAIN) { 325 if (exfat_chain_cont_cluster(sb, p_chain->dir, 326 num_clusters)) { 327 ret = -EIO; 328 goto free_cluster; 329 } 330 p_chain->flags = ALLOC_FAT_CHAIN; 331 } 332 333 /* update allocation bitmap */ 334 if (exfat_set_bitmap(inode, new_clu)) { 335 ret = -EIO; 336 goto free_cluster; 337 } 338 339 num_clusters++; 340 341 /* update FAT table */ 342 if (p_chain->flags == ALLOC_FAT_CHAIN) { 343 if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { 344 ret = -EIO; 345 goto free_cluster; 346 } 347 } 348 349 if (p_chain->dir == EXFAT_EOF_CLUSTER) { 350 p_chain->dir = new_clu; 351 } else if (p_chain->flags == ALLOC_FAT_CHAIN) { 352 if (exfat_ent_set(sb, last_clu, new_clu)) { 353 ret = -EIO; 354 goto free_cluster; 355 } 356 } 357 last_clu = new_clu; 358 359 if (--num_alloc == 0) { 360 sbi->clu_srch_ptr = hint_clu; 361 sbi->used_clusters += num_clusters; 362 363 p_chain->size += num_clusters; 364 return 0; 365 } 366 367 hint_clu = new_clu + 1; 368 if (hint_clu >= sbi->num_clusters) { 369 hint_clu = EXFAT_FIRST_CLUSTER; 370 371 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 372 if (exfat_chain_cont_cluster(sb, p_chain->dir, 373 num_clusters)) { 374 ret = -EIO; 375 goto free_cluster; 376 } 377 p_chain->flags = ALLOC_FAT_CHAIN; 378 } 379 } 380 } 381free_cluster: 382 if (num_clusters) 383 exfat_free_cluster(inode, p_chain); 384 return ret; 385} 386 387int exfat_count_num_clusters(struct super_block *sb, 388 struct exfat_chain *p_chain, unsigned int *ret_count) 389{ 390 unsigned int i, count; 391 unsigned int clu; 392 struct exfat_sb_info *sbi = EXFAT_SB(sb); 393 394 if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { 395 *ret_count = 0; 396 return 0; 397 } 398 399 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { 400 *ret_count = p_chain->size; 401 return 0; 402 } 403 404 clu = p_chain->dir; 405 count = 0; 406 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { 407 count++; 408 if (exfat_ent_get(sb, clu, &clu)) 409 return -EIO; 410 if (clu == EXFAT_EOF_CLUSTER) 411 break; 412 } 413 414 *ret_count = count; 415 return 0; 416} 417