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 (!is_valid_cluster(sbi, p_chain->dir)) {
 173                 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
 174                 return -EIO;
 175         }
 176
 177         set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
 178         clu = p_chain->dir;
 179
 180         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 181                 do {
 182                         exfat_clear_bitmap(inode, clu);
 183                         clu++;
 184
 185                         num_clusters++;
 186                 } while (num_clusters < p_chain->size);
 187         } else {
 188                 do {
 189                         exfat_clear_bitmap(inode, clu);
 190
 191                         if (exfat_get_next_cluster(sb, &clu))
 192                                 goto dec_used_clus;
 193
 194                         num_clusters++;
 195                 } while (clu != EXFAT_EOF_CLUSTER);
 196         }
 197
 198 dec_used_clus:
 199         sbi->used_clusters -= num_clusters;
 200         return 0;
 201 }
 202
 203 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
 204                 unsigned int *ret_clu)
 205 {
 206         unsigned int clu, next;
 207         unsigned int count = 0;
 208
 209         next = p_chain->dir;
 210         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 211                 *ret_clu = next + p_chain->size - 1;
 212                 return 0;
 213         }
 214
 215         do {
 216                 count++;
 217                 clu = next;
 218                 if (exfat_ent_get(sb, clu, &next))
 219                         return -EIO;
 220         } while (next != EXFAT_EOF_CLUSTER);
 221
 222         if (p_chain->size != count) {
 223                 exfat_fs_error(sb,
 224                         "bogus directory size (clus : ondisk(%d) != counted(%d))",
 225                         p_chain->size, count);
 226                 return -EIO;
 227         }
 228
 229         *ret_clu = clu;
 230         return 0;
 231 }
 232
 233 static inline int exfat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
 234 {
 235         int i, err = 0;
 236
 237         for (i = 0; i < nr_bhs; i++)
 238                 write_dirty_buffer(bhs[i], 0);
 239
 240         for (i = 0; i < nr_bhs; i++) {
 241                 wait_on_buffer(bhs[i]);
 242                 if (!err && !buffer_uptodate(bhs[i]))
 243                         err = -EIO;
 244         }
 245         return err;
 246 }
 247
 248 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
 249 {
 250         struct super_block *sb = dir->i_sb;
 251         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 252         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
 253         int nr_bhs = MAX_BUF_PER_PAGE;
 254         sector_t blknr, last_blknr;
 255         int err, i, n;
 256
 257         blknr = exfat_cluster_to_sector(sbi, clu);
 258         last_blknr = blknr + sbi->sect_per_clus;
 259
 260         if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
 261                 exfat_fs_error_ratelimit(sb,
 262                         "%s: out of range(sect:%llu len:%u)",
 263                         __func__, (unsigned long long)blknr,
 264                         sbi->sect_per_clus);
 265                 return -EIO;
 266         }
 267
 268         /* Zeroing the unused blocks on this cluster */
 269         n = 0;
 270         while (blknr < last_blknr) {
 271                 bhs[n] = sb_getblk(sb, blknr);
 272                 if (!bhs[n]) {
 273                         err = -ENOMEM;
 274                         goto release_bhs;
 275                 }
 276                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
 277                 exfat_update_bh(sb, bhs[n], 0);
 278
 279                 n++;
 280                 blknr++;
 281
 282                 if (n == nr_bhs) {
 283                         if (IS_DIRSYNC(dir)) {
 284                                 err = exfat_sync_bhs(bhs, n);
 285                                 if (err)
 286                                         goto release_bhs;
 287                         }
 288
 289                         for (i = 0; i < n; i++)
 290                                 brelse(bhs[i]);
 291                         n = 0;
 292                 }
 293         }
 294
 295         if (IS_DIRSYNC(dir)) {
 296                 err = exfat_sync_bhs(bhs, n);
 297                 if (err)
 298                         goto release_bhs;
 299         }
 300
 301         for (i = 0; i < n; i++)
 302                 brelse(bhs[i]);
 303
 304         return 0;
 305
 306 release_bhs:
 307         exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
 308         for (i = 0; i < n; i++)
 309                 bforget(bhs[i]);
 310         return err;
 311 }
 312
 313 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 314                 struct exfat_chain *p_chain)
 315 {
 316         int ret = -ENOSPC;
 317         unsigned int num_clusters = 0, total_cnt;
 318         unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
 319         struct super_block *sb = inode->i_sb;
 320         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 321
 322         total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
 323
 324         if (unlikely(total_cnt < sbi->used_clusters)) {
 325                 exfat_fs_error_ratelimit(sb,
 326                         "%s: invalid used clusters(t:%u,u:%u)\n",
 327                         __func__, total_cnt, sbi->used_clusters);
 328                 return -EIO;
 329         }
 330
 331         if (num_alloc > total_cnt - sbi->used_clusters)
 332                 return -ENOSPC;
 333
 334         hint_clu = p_chain->dir;
 335         /* find new cluster */
 336         if (hint_clu == EXFAT_EOF_CLUSTER) {
 337                 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
 338                         exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
 339                                   sbi->clu_srch_ptr);
 340                         sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 341                 }
 342
 343                 hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr);
 344                 if (hint_clu == EXFAT_EOF_CLUSTER)
 345                         return -ENOSPC;
 346         }
 347
 348         /* check cluster validation */
 349         if (!is_valid_cluster(sbi, hint_clu)) {
 350                 exfat_err(sb, "hint_cluster is invalid (%u)",
 351                         hint_clu);
 352                 hint_clu = EXFAT_FIRST_CLUSTER;
 353                 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 354                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 355                                         num_clusters))
 356                                 return -EIO;
 357                         p_chain->flags = ALLOC_FAT_CHAIN;
 358                 }
 359         }
 360
 361         set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
 362
 363         p_chain->dir = EXFAT_EOF_CLUSTER;
 364
 365         while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
 366                EXFAT_EOF_CLUSTER) {
 367                 if (new_clu != hint_clu &&
 368                     p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 369                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 370                                         num_clusters)) {
 371                                 ret = -EIO;
 372                                 goto free_cluster;
 373                         }
 374                         p_chain->flags = ALLOC_FAT_CHAIN;
 375                 }
 376
 377                 /* update allocation bitmap */
 378                 if (exfat_set_bitmap(inode, new_clu)) {
 379                         ret = -EIO;
 380                         goto free_cluster;
 381                 }
 382
 383                 num_clusters++;
 384
 385                 /* update FAT table */
 386                 if (p_chain->flags == ALLOC_FAT_CHAIN) {
 387                         if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
 388                                 ret = -EIO;
 389                                 goto free_cluster;
 390                         }
 391                 }
 392
 393                 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
 394                         p_chain->dir = new_clu;
 395                 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
 396                         if (exfat_ent_set(sb, last_clu, new_clu)) {
 397                                 ret = -EIO;
 398                                 goto free_cluster;
 399                         }
 400                 }
 401                 last_clu = new_clu;
 402
 403                 if (--num_alloc == 0) {
 404                         sbi->clu_srch_ptr = hint_clu;
 405                         sbi->used_clusters += num_clusters;
 406
 407                         p_chain->size += num_clusters;
 408                         return 0;
 409                 }
 410
 411                 hint_clu = new_clu + 1;
 412                 if (hint_clu >= sbi->num_clusters) {
 413                         hint_clu = EXFAT_FIRST_CLUSTER;
 414
 415                         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 416                                 if (exfat_chain_cont_cluster(sb, p_chain->dir,
 417                                                 num_clusters)) {
 418                                         ret = -EIO;
 419                                         goto free_cluster;
 420                                 }
 421                                 p_chain->flags = ALLOC_FAT_CHAIN;
 422                         }
 423                 }
 424         }
 425 free_cluster:
 426         if (num_clusters)
 427                 exfat_free_cluster(inode, p_chain);
 428         return ret;
 429 }
 430
 431 int exfat_count_num_clusters(struct super_block *sb,
 432                 struct exfat_chain *p_chain, unsigned int *ret_count)
 433 {
 434         unsigned int i, count;
 435         unsigned int clu;
 436         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 437
 438         if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
 439                 *ret_count = 0;
 440                 return 0;
 441         }
 442
 443         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 444                 *ret_count = p_chain->size;
 445                 return 0;
 446         }
 447
 448         clu = p_chain->dir;
 449         count = 0;
 450         for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
 451                 count++;
 452                 if (exfat_ent_get(sb, clu, &clu))
 453                         return -EIO;
 454                 if (clu == EXFAT_EOF_CLUSTER)
 455                         break;
 456         }
 457
 458         *ret_count = count;
 459         return 0;
 460 }