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 /* This function must be called with bitmap_lock held */
 147 static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
 148 {
 149         struct super_block *sb = inode->i_sb;
 150         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 151         int cur_cmap_i, next_cmap_i;
 152         unsigned int num_clusters = 0;
 153         unsigned int clu;
 154
 155         /* invalid cluster number */
 156         if (p_chain->dir == EXFAT_FREE_CLUSTER ||
 157             p_chain->dir == EXFAT_EOF_CLUSTER ||
 158             p_chain->dir < EXFAT_FIRST_CLUSTER)
 159                 return 0;
 160
 161         /* no cluster to truncate */
 162         if (p_chain->size == 0)
 163                 return 0;
 164
 165         /* check cluster validation */
 166         if (!is_valid_cluster(sbi, p_chain->dir)) {
 167                 exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
 168                 return -EIO;
 169         }
 170
 171         clu = p_chain->dir;
 172
 173         cur_cmap_i = next_cmap_i =
 174                 BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu));
 175
 176         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 177                 unsigned int last_cluster = p_chain->dir + p_chain->size - 1;
 178                 do {
 179                         bool sync = false;
 180
 181                         if (clu < last_cluster)
 182                                 next_cmap_i =
 183                                   BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1));
 184
 185                         /* flush bitmap only if index would be changed or for last cluster */
 186                         if (clu == last_cluster || cur_cmap_i != next_cmap_i) {
 187                                 sync = true;
 188                                 cur_cmap_i = next_cmap_i;
 189                         }
 190
 191                         exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
 192                         clu++;
 193                         num_clusters++;
 194                 } while (num_clusters < p_chain->size);
 195         } else {
 196                 do {
 197                         bool sync = false;
 198                         unsigned int n_clu = clu;
 199                         int err = exfat_get_next_cluster(sb, &n_clu);
 200
 201                         if (err || n_clu == EXFAT_EOF_CLUSTER)
 202                                 sync = true;
 203                         else
 204                                 next_cmap_i =
 205                                   BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu));
 206
 207                         if (cur_cmap_i != next_cmap_i) {
 208                                 sync = true;
 209                                 cur_cmap_i = next_cmap_i;
 210                         }
 211
 212                         exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode)));
 213                         clu = n_clu;
 214                         num_clusters++;
 215
 216                         if (err)
 217                                 goto dec_used_clus;
 218                 } while (clu != EXFAT_EOF_CLUSTER);
 219         }
 220
 221 dec_used_clus:
 222         sbi->used_clusters -= num_clusters;
 223         return 0;
 224 }
 225
 226 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
 227 {
 228         int ret = 0;
 229
 230         mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
 231         ret = __exfat_free_cluster(inode, p_chain);
 232         mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock);
 233
 234         return ret;
 235 }
 236
 237 int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
 238                 unsigned int *ret_clu)
 239 {
 240         unsigned int clu, next;
 241         unsigned int count = 0;
 242
 243         next = p_chain->dir;
 244         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 245                 *ret_clu = next + p_chain->size - 1;
 246                 return 0;
 247         }
 248
 249         do {
 250                 count++;
 251                 clu = next;
 252                 if (exfat_ent_get(sb, clu, &next))
 253                         return -EIO;
 254         } while (next != EXFAT_EOF_CLUSTER);
 255
 256         if (p_chain->size != count) {
 257                 exfat_fs_error(sb,
 258                         "bogus directory size (clus : ondisk(%d) != counted(%d))",
 259                         p_chain->size, count);
 260                 return -EIO;
 261         }
 262
 263         *ret_clu = clu;
 264         return 0;
 265 }
 266
 267 int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
 268 {
 269         struct super_block *sb = dir->i_sb;
 270         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 271         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
 272         int nr_bhs = MAX_BUF_PER_PAGE;
 273         sector_t blknr, last_blknr;
 274         int err, i, n;
 275
 276         blknr = exfat_cluster_to_sector(sbi, clu);
 277         last_blknr = blknr + sbi->sect_per_clus;
 278
 279         if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) {
 280                 exfat_fs_error_ratelimit(sb,
 281                         "%s: out of range(sect:%llu len:%u)",
 282                         __func__, (unsigned long long)blknr,
 283                         sbi->sect_per_clus);
 284                 return -EIO;
 285         }
 286
 287         /* Zeroing the unused blocks on this cluster */
 288         while (blknr < last_blknr) {
 289                 for (n = 0; n < nr_bhs && blknr < last_blknr; n++, blknr++) {
 290                         bhs[n] = sb_getblk(sb, blknr);
 291                         if (!bhs[n]) {
 292                                 err = -ENOMEM;
 293                                 goto release_bhs;
 294                         }
 295                         memset(bhs[n]->b_data, 0, sb->s_blocksize);
 296                 }
 297
 298                 err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
 299                 if (err)
 300                         goto release_bhs;
 301
 302                 for (i = 0; i < n; i++)
 303                         brelse(bhs[i]);
 304         }
 305         return 0;
 306
 307 release_bhs:
 308         exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
 309         for (i = 0; i < n; i++)
 310                 bforget(bhs[i]);
 311         return err;
 312 }
 313
 314 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 315                 struct exfat_chain *p_chain, bool sync_bmap)
 316 {
 317         int ret = -ENOSPC;
 318         unsigned int num_clusters = 0, total_cnt;
 319         unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
 320         struct super_block *sb = inode->i_sb;
 321         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 322
 323         total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi);
 324
 325         if (unlikely(total_cnt < sbi->used_clusters)) {
 326                 exfat_fs_error_ratelimit(sb,
 327                         "%s: invalid used clusters(t:%u,u:%u)\n",
 328                         __func__, total_cnt, sbi->used_clusters);
 329                 return -EIO;
 330         }
 331
 332         if (num_alloc > total_cnt - sbi->used_clusters)
 333                 return -ENOSPC;
 334
 335         mutex_lock(&sbi->bitmap_lock);
 336
 337         hint_clu = p_chain->dir;
 338         /* find new cluster */
 339         if (hint_clu == EXFAT_EOF_CLUSTER) {
 340                 if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
 341                         exfat_err(sb, "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                         ret = -ENOSPC;
 349                         goto unlock;
 350                 }
 351         }
 352
 353         /* check cluster validation */
 354         if (!is_valid_cluster(sbi, hint_clu)) {
 355                 exfat_err(sb, "hint_cluster is invalid (%u)",
 356                         hint_clu);
 357                 hint_clu = EXFAT_FIRST_CLUSTER;
 358                 if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 359                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 360                                         num_clusters)) {
 361                                 ret = -EIO;
 362                                 goto unlock;
 363                         }
 364                         p_chain->flags = ALLOC_FAT_CHAIN;
 365                 }
 366         }
 367
 368         p_chain->dir = EXFAT_EOF_CLUSTER;
 369
 370         while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) !=
 371                EXFAT_EOF_CLUSTER) {
 372                 if (new_clu != hint_clu &&
 373                     p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 374                         if (exfat_chain_cont_cluster(sb, p_chain->dir,
 375                                         num_clusters)) {
 376                                 ret = -EIO;
 377                                 goto free_cluster;
 378                         }
 379                         p_chain->flags = ALLOC_FAT_CHAIN;
 380                 }
 381
 382                 /* update allocation bitmap */
 383                 if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
 384                         ret = -EIO;
 385                         goto free_cluster;
 386                 }
 387
 388                 num_clusters++;
 389
 390                 /* update FAT table */
 391                 if (p_chain->flags == ALLOC_FAT_CHAIN) {
 392                         if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
 393                                 ret = -EIO;
 394                                 goto free_cluster;
 395                         }
 396                 }
 397
 398                 if (p_chain->dir == EXFAT_EOF_CLUSTER) {
 399                         p_chain->dir = new_clu;
 400                 } else if (p_chain->flags == ALLOC_FAT_CHAIN) {
 401                         if (exfat_ent_set(sb, last_clu, new_clu)) {
 402                                 ret = -EIO;
 403                                 goto free_cluster;
 404                         }
 405                 }
 406                 last_clu = new_clu;
 407
 408                 if (--num_alloc == 0) {
 409                         sbi->clu_srch_ptr = hint_clu;
 410                         sbi->used_clusters += num_clusters;
 411
 412                         p_chain->size += num_clusters;
 413                         mutex_unlock(&sbi->bitmap_lock);
 414                         return 0;
 415                 }
 416
 417                 hint_clu = new_clu + 1;
 418                 if (hint_clu >= sbi->num_clusters) {
 419                         hint_clu = EXFAT_FIRST_CLUSTER;
 420
 421                         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 422                                 if (exfat_chain_cont_cluster(sb, p_chain->dir,
 423                                                 num_clusters)) {
 424                                         ret = -EIO;
 425                                         goto free_cluster;
 426                                 }
 427                                 p_chain->flags = ALLOC_FAT_CHAIN;
 428                         }
 429                 }
 430         }
 431 free_cluster:
 432         if (num_clusters)
 433                 __exfat_free_cluster(inode, p_chain);
 434 unlock:
 435         mutex_unlock(&sbi->bitmap_lock);
 436         return ret;
 437 }
 438
 439 int exfat_count_num_clusters(struct super_block *sb,
 440                 struct exfat_chain *p_chain, unsigned int *ret_count)
 441 {
 442         unsigned int i, count;
 443         unsigned int clu;
 444         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 445
 446         if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) {
 447                 *ret_count = 0;
 448                 return 0;
 449         }
 450
 451         if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 452                 *ret_count = p_chain->size;
 453                 return 0;
 454         }
 455
 456         clu = p_chain->dir;
 457         count = 0;
 458         for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) {
 459                 count++;
 460                 if (exfat_ent_get(sb, clu, &clu))
 461                         return -EIO;
 462                 if (clu == EXFAT_EOF_CLUSTER)
 463                         break;
 464         }
 465
 466         *ret_count = count;
 467         return 0;
 468 }