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 int 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
 128 int 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
 146 int 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
 189 dec_used_clus:
 190         sbi->used_clusters -= num_clusters;
 191         return 0;
 192 }
 193
 194 int 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
 224 int 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
 264 release_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
 271 int 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         }
 381 free_cluster:
 382         if (num_clusters)
 383                 exfat_free_cluster(inode, p_chain);
 384         return ret;
 385 }
 386
 387 int 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 }