fs/exfat/fatent.c

   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(sb, 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 (p_chain->dir < 2 && p_chain->dir >= sbi->num_clusters) {
 173                 exfat_msg(sb, KERN_ERR, "invalid start cluster (%u)",
 174                                 p_chain->dir);
 175                 return -EIO;
 176         }
 177
 178         set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
 179         clu = p_chain->dir;
 180
 181         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 182                 do {
 183                         exfat_clear_bitmap(inode, clu);
 184                         clu++;
 185
 186                         num_clusters++;
 187                 } while (num_clusters < p_chain->size);
 188         } else {
 189                 do {
 190                         exfat_clear_bitmap(inode, clu);
 191
 192                         if (exfat_get_next_cluster(sb, &clu))
 193                                 goto dec_used_clus;
 194
 195                         num_clusters++;
 196                 } while (clu != EXFAT_EOF_CLUSTER);
 197         }
 198
 199 dec_used_clus:
 200         sbi->used_clusters -= num_clusters;
 201         return 0;
 202 }
 203
 204 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
 205                 unsigned int *ret_clu)
 206 {
 207         unsigned int clu, next;
 208         unsigned int count = 0;
 209
 210         next = p_chain->dir;
 211         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 212                 *ret_clu = next + p_chain->size - 1;
 213                 return 0;
 214         }
 215
 216         do {
 217                 count++;
 218                 clu = next;
 219                 if (exfat_ent_get(sb, clu, &next))
 220                         return -EIO;
 221         } while (next != EXFAT_EOF_CLUSTER);
 222
 223         if (p_chain->size != count) {
 224                 exfat_fs_error(sb,
 225                         "bogus directory size (clus : ondisk(%d) != counted(%d))",
 226                         p_chain->size, count);
 227                 return -EIO;
 228         }
 229
 230         *ret_clu = clu;
 231         return 0;
 232 }
 233
 234 static inline int exfat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
 235 {
 236         int i, err = 0;
 237
 238         for (i = 0; i < nr_bhs; i++)
 239                 write_dirty_buffer(bhs[i], 0);
 240
 241         for (i = 0; i < nr_bhs; i++) {
 242                 wait_on_buffer(bhs[i]);
 243                 if (!err && !buffer_uptodate(bhs[i]))
 244                         err = -EIO;
 245         }
 246         return err;
 247 }
 248
 249 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
 250 {
 251         struct super_block *sb = dir->i_sb;
 252         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 253         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
 254         int nr_bhs = MAX_BUF_PER_PAGE;
 255         sector_t blknr, last_blknr;
 256         int err, i, n;
 257
 258         blknr = exfat_cluster_to_sector(sbi, clu);
 259         last_blknr = blknr + sbi->sect_per_clus;
 260
 261         if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
 262                 exfat_fs_error_ratelimit(sb,
 263                         "%s: out of range(sect:%llu len:%u)",
 264                         __func__, (unsigned long long)blknr,
 265                         sbi->sect_per_clus);
 266                 return -EIO;
 267         }
 268
 269         /* Zeroing the unused blocks on this cluster */
 270         n = 0;
 271         while (blknr < last_blknr) {
 272                 bhs[n] = sb_getblk(sb, blknr);
 273                 if (!bhs[n]) {
 274                         err = -ENOMEM;
 275                         goto release_bhs;
 276                 }
 277                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
 278                 exfat_update_bh(sb, bhs[n], 0);
 279
 280                 n++;
 281                 blknr++;
 282
 283                 if (n == nr_bhs) {
 284                         if (IS_DIRSYNC(dir)) {
 285                                 err = exfat_sync_bhs(bhs, n);
 286                                 if (err)
 287                                         goto release_bhs;
 288                         }
 289
 290                         for (i = 0; i < n; i++)
 291                                 brelse(bhs[i]);
 292                         n = 0;
 293                 }
 294         }
 295
 296         if (IS_DIRSYNC(dir)) {
 297                 err = exfat_sync_bhs(bhs, n);
 298                 if (err)
 299                         goto release_bhs;
 300         }
 301
 302         for (i = 0; i < n; i++)
 303                 brelse(bhs[i]);
 304
 305         return 0;
 306
 307 release_bhs:
 308         exfat_msg(sb, KERN_ERR, "failed zeroed sect %llu\n",
 309                 (unsigned long long)blknr);
 310         for (i = 0; i < n; i++)
 311                 bforget(bhs[i]);
 312         return err;
 313 }
 314
 315 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 316                 struct exfat_chain *p_chain)
 317 {
 318         int ret = -ENOSPC;
 319         unsigned int num_clusters = 0, total_cnt;
 320         unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
 321         struct super_block *sb = inode->i_sb;
 322         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 323
 324         total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
 325
 326         if (unlikely(total_cnt < sbi->used_clusters)) {
 327                 exfat_fs_error_ratelimit(sb,
 328                         "%s: invalid used clusters(t:%u,u:%u)\n",
 329                         __func__, total_cnt, sbi->used_clusters);
 330                 return -EIO;
 331         }
 332
 333         if (num_alloc > total_cnt - sbi->used_clusters)
 334                 return -ENOSPC;
 335
 336         hint_clu = p_chain->dir;
 337         /* find new cluster */
 338         if (hint_clu == EXFAT_EOF_CLUSTER) {
 339                 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
 340                         exfat_msg(sb, KERN_ERR,
 341                                 "sbi->clu_srch_ptr is invalid (%u)\n",
 342                                 sbi->clu_srch_ptr);
 343                         sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 344                 }
 345
 346                 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
 347                 if (hint_clu == EXFAT_EOF_CLUSTER)
 348                         return -ENOSPC;
 349         }
 350
 351         /* check cluster validation */
 352         if (hint_clu < EXFAT_FIRST_CLUSTER && hint_clu >= sbi->num_clusters) {
 353                 exfat_msg(sb, KERN_ERR, "hint_cluster is invalid (%u)\n",
 354                         hint_clu);
 355                 hint_clu = EXFAT_FIRST_CLUSTER;
 356                 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 357                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 358                                         num_clusters))
 359                                 return -EIO;
 360                         p_chain->flags = ALLOC_FAT_CHAIN;
 361                 }
 362         }
 363
 364         set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
 365
 366         p_chain->dir = EXFAT_EOF_CLUSTER;
 367
 368         while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
 369                EXFAT_EOF_CLUSTER) {
 370                 if (new_clu != hint_clu &&
 371                     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                 /* update allocation bitmap */
 381                 if (exfat_set_bitmap(inode, new_clu)) {
 382                         ret = -EIO;
 383                         goto free_cluster;
 384                 }
 385
 386                 num_clusters++;
 387
 388                 /* update FAT table */
 389                 if (p_chain->flags == ALLOC_FAT_CHAIN) {
 390                         if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
 391                                 ret = -EIO;
 392                                 goto free_cluster;
 393                         }
 394                 }
 395
 396                 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
 397                         p_chain->dir = new_clu;
 398                 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
 399                         if (exfat_ent_set(sb, last_clu, new_clu)) {
 400                                 ret = -EIO;
 401                                 goto free_cluster;
 402                         }
 403                 }
 404                 last_clu = new_clu;
 405
 406                 if (--num_alloc == 0) {
 407                         sbi->clu_srch_ptr = hint_clu;
 408                         sbi->used_clusters += num_clusters;
 409
 410                         p_chain->size += num_clusters;
 411                         return 0;
 412                 }
 413
 414                 hint_clu = new_clu + 1;
 415                 if (hint_clu >= sbi->num_clusters) {
 416                         hint_clu = EXFAT_FIRST_CLUSTER;
 417
 418                         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 419                                 if (exfat_chain_cont_cluster(sb, p_chain->dir,
 420                                                 num_clusters)) {
 421                                         ret = -EIO;
 422                                         goto free_cluster;
 423                                 }
 424                                 p_chain->flags = ALLOC_FAT_CHAIN;
 425                         }
 426                 }
 427         }
 428 free_cluster:
 429         if (num_clusters)
 430                 exfat_free_cluster(inode, p_chain);
 431         return ret;
 432 }
 433
 434 int exfat_count_num_clusters(struct super_block *sb,
 435                 struct exfat_chain *p_chain, unsigned int *ret_count)
 436 {
 437         unsigned int i, count;
 438         unsigned int clu;
 439         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 440
 441         if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
 442                 *ret_count = 0;
 443                 return 0;
 444         }
 445
 446         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 447                 *ret_count = p_chain->size;
 448                 return 0;
 449         }
 450
 451         clu = p_chain->dir;
 452         count = 0;
 453         for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
 454                 count++;
 455                 if (exfat_ent_get(sb, clu, &clu))
 456                         return -EIO;
 457                 if (clu == EXFAT_EOF_CLUSTER)
 458                         break;
 459         }
 460
 461         *ret_count = count;
 462         return 0;
 463 }