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(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         int cur_cmap_i, next_cmap_i;
 161
 162         /* invalid cluster number */
 163         if (p_chain->dir == EXFAT_FREE_CLUSTER ||
 164             p_chain->dir == EXFAT_EOF_CLUSTER ||
 165             p_chain->dir < EXFAT_FIRST_CLUSTER)
 166                 return 0;
 167
 168         /* no cluster to truncate */
 169         if (p_chain->size == 0)
 170                 return 0;
 171
 172         /* check cluster validation */
 173         if (!is_valid_cluster(sbi, p_chain->dir)) {
 174                 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
 175                 return -EIO;
 176         }
 177
 178         clu = p_chain->dir;
 179
 180         cur_cmap_i = next_cmap_i =
 181                 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu));
 182
 183         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 184                 unsigned int last_cluster = p_chain->dir + p_chain->size - 1;
 185                 do {
 186                         bool sync = false;
 187
 188                         if (clu < last_cluster)
 189                                 next_cmap_i =
 190                                   BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1));
 191
 192                         /* flush bitmap only if index would be changed or for last cluster */
 193                         if (clu == last_cluster || cur_cmap_i != next_cmap_i) {
 194                                 sync = true;
 195                                 cur_cmap_i = next_cmap_i;
 196                         }
 197
 198                         exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
 199                         clu++;
 200                         num_clusters++;
 201                 } while (num_clusters < p_chain->size);
 202         } else {
 203                 do {
 204                         bool sync = false;
 205                         unsigned int n_clu = clu;
 206                         int err = exfat_get_next_cluster(sb, &n_clu);
 207
 208                         if (err || n_clu == EXFAT_EOF_CLUSTER)
 209                                 sync = true;
 210                         else
 211                                 next_cmap_i =
 212                                   BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu));
 213
 214                         if (cur_cmap_i != next_cmap_i) {
 215                                 sync = true;
 216                                 cur_cmap_i = next_cmap_i;
 217                         }
 218
 219                         exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
 220                         clu = n_clu;
 221                         num_clusters++;
 222
 223                         if (err)
 224                                 goto dec_used_clus;
 225                 } while (clu != EXFAT_EOF_CLUSTER);
 226         }
 227
 228 dec_used_clus:
 229         sbi->used_clusters -= num_clusters;
 230         return 0;
 231 }
 232
 233 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
 234                 unsigned int *ret_clu)
 235 {
 236         unsigned int clu, next;
 237         unsigned int count = 0;
 238
 239         next = p_chain->dir;
 240         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 241                 *ret_clu = next + p_chain->size - 1;
 242                 return 0;
 243         }
 244
 245         do {
 246                 count++;
 247                 clu = next;
 248                 if (exfat_ent_get(sb, clu, &next))
 249                         return -EIO;
 250         } while (next != EXFAT_EOF_CLUSTER);
 251
 252         if (p_chain->size != count) {
 253                 exfat_fs_error(sb,
 254                         "bogus directory size (clus : ondisk(%d) != counted(%d))",
 255                         p_chain->size, count);
 256                 return -EIO;
 257         }
 258
 259         *ret_clu = clu;
 260         return 0;
 261 }
 262
 263 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
 264 {
 265         struct super_block *sb = dir->i_sb;
 266         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 267         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
 268         int nr_bhs = MAX_BUF_PER_PAGE;
 269         sector_t blknr, last_blknr;
 270         int err, i, n;
 271
 272         blknr = exfat_cluster_to_sector(sbi, clu);
 273         last_blknr = blknr + sbi->sect_per_clus;
 274
 275         if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
 276                 exfat_fs_error_ratelimit(sb,
 277                         "%s: out of range(sect:%llu len:%u)",
 278                         __func__, (unsigned long long)blknr,
 279                         sbi->sect_per_clus);
 280                 return -EIO;
 281         }
 282
 283         /* Zeroing the unused blocks on this cluster */
 284         while (blknr < last_blknr) {
 285                 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) {
 286                         bhs[n] = sb_getblk(sb, blknr);
 287                         if (!bhs[n]) {
 288                                 err = -ENOMEM;
 289                                 goto release_bhs;
 290                         }
 291                         memset(bhs[n]->b_data, 0, sb->s_blocksize);
 292                 }
 293
 294                 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
 295                 if (err)
 296                         goto release_bhs;
 297
 298                 for (i = 0; i < n; i++)
 299                         brelse(bhs[i]);
 300         }
 301         return 0;
 302
 303 release_bhs:
 304         exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
 305         for (i = 0; i < n; i++)
 306                 bforget(bhs[i]);
 307         return err;
 308 }
 309
 310 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 311                 struct exfat_chain *p_chain)
 312 {
 313         int ret = -ENOSPC;
 314         unsigned int num_clusters = 0, total_cnt;
 315         unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
 316         struct super_block *sb = inode->i_sb;
 317         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 318
 319         total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
 320
 321         if (unlikely(total_cnt < sbi->used_clusters)) {
 322                 exfat_fs_error_ratelimit(sb,
 323                         "%s: invalid used clusters(t:%u,u:%u)\n",
 324                         __func__, total_cnt, sbi->used_clusters);
 325                 return -EIO;
 326         }
 327
 328         if (num_alloc > total_cnt - sbi->used_clusters)
 329                 return -ENOSPC;
 330
 331         hint_clu = p_chain->dir;
 332         /* find new cluster */
 333         if (hint_clu == EXFAT_EOF_CLUSTER) {
 334                 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
 335                         exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
 336                                   sbi->clu_srch_ptr);
 337                         sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 338                 }
 339
 340                 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
 341                 if (hint_clu == EXFAT_EOF_CLUSTER)
 342                         return -ENOSPC;
 343         }
 344
 345         /* check cluster validation */
 346         if (!is_valid_cluster(sbi, hint_clu)) {
 347                 exfat_err(sb, "hint_cluster is invalid (%u)",
 348                         hint_clu);
 349                 hint_clu = EXFAT_FIRST_CLUSTER;
 350                 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 351                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 352                                         num_clusters))
 353                                 return -EIO;
 354                         p_chain->flags = ALLOC_FAT_CHAIN;
 355                 }
 356         }
 357
 358         p_chain->dir = EXFAT_EOF_CLUSTER;
 359
 360         while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
 361                EXFAT_EOF_CLUSTER) {
 362                 if (new_clu != hint_clu &&
 363                     p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 364                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 365                                         num_clusters)) {
 366                                 ret = -EIO;
 367                                 goto free_cluster;
 368                         }
 369                         p_chain->flags = ALLOC_FAT_CHAIN;
 370                 }
 371
 372                 /* update allocation bitmap */
 373                 if (exfat_set_bitmap(inode, new_clu)) {
 374                         ret = -EIO;
 375                         goto free_cluster;
 376                 }
 377
 378                 num_clusters++;
 379
 380                 /* update FAT table */
 381                 if (p_chain->flags == ALLOC_FAT_CHAIN) {
 382                         if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
 383                                 ret = -EIO;
 384                                 goto free_cluster;
 385                         }
 386                 }
 387
 388                 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
 389                         p_chain->dir = new_clu;
 390                 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
 391                         if (exfat_ent_set(sb, last_clu, new_clu)) {
 392                                 ret = -EIO;
 393                                 goto free_cluster;
 394                         }
 395                 }
 396                 last_clu = new_clu;
 397
 398                 if (--num_alloc == 0) {
 399                         sbi->clu_srch_ptr = hint_clu;
 400                         sbi->used_clusters += num_clusters;
 401
 402                         p_chain->size += num_clusters;
 403                         return 0;
 404                 }
 405
 406                 hint_clu = new_clu + 1;
 407                 if (hint_clu >= sbi->num_clusters) {
 408                         hint_clu = EXFAT_FIRST_CLUSTER;
 409
 410                         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 411                                 if (exfat_chain_cont_cluster(sb, p_chain->dir,
 412                                                 num_clusters)) {
 413                                         ret = -EIO;
 414                                         goto free_cluster;
 415                                 }
 416                                 p_chain->flags = ALLOC_FAT_CHAIN;
 417                         }
 418                 }
 419         }
 420 free_cluster:
 421         if (num_clusters)
 422                 exfat_free_cluster(inode, p_chain);
 423         return ret;
 424 }
 425
 426 int exfat_count_num_clusters(struct super_block *sb,
 427                 struct exfat_chain *p_chain, unsigned int *ret_count)
 428 {
 429         unsigned int i, count;
 430         unsigned int clu;
 431         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 432
 433         if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
 434                 *ret_count = 0;
 435                 return 0;
 436         }
 437
 438         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 439                 *ret_count = p_chain->size;
 440                 return 0;
 441         }
 442
 443         clu = p_chain->dir;
 444         count = 0;
 445         for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
 446                 count++;
 447                 if (exfat_ent_get(sb, clu, &clu))
 448                         return -EIO;
 449                 if (clu == EXFAT_EOF_CLUSTER)
 450                         break;
 451         }
 452
 453         *ret_count = count;
 454         return 0;
 455 }