fs/exfat/dir.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 <linux/bio.h>
   8 #include <linux/buffer_head.h>
   9
  10 #include "exfat_raw.h"
  11 #include "exfat_fs.h"
  12
  13 static int exfat_extract_uni_name(struct exfat_dentry *ep,
  14                 unsigned short *uniname)
  15 {
  16         int i, len = 0;
  17
  18         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
  19                 *uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
  20                 if (*uniname == 0x0)
  21                         return len;
  22                 uniname++;
  23                 len++;
  24         }
  25
  26         *uniname = 0x0;
  27         return len;
  28
  29 }
  30
  31 static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
  32                 struct exfat_chain *p_dir, int entry, unsigned short *uniname)
  33 {
  34         int i;
  35         struct exfat_entry_set_cache *es;
  36
  37         es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
  38         if (!es)
  39                 return;
  40
  41         /*
  42          * First entry  : file entry
  43          * Second entry : stream-extension entry
  44          * Third entry  : first file-name entry
  45          * So, the index of first file-name dentry should start from 2.
  46          */
  47         for (i = 2; i < es->num_entries; i++) {
  48                 struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
  49
  50                 /* end of name entry */
  51                 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
  52                         break;
  53
  54                 exfat_extract_uni_name(ep, uniname);
  55                 uniname += EXFAT_FILE_NAME_LEN;
  56         }
  57
  58         exfat_free_dentry_set(es, false);
  59 }
  60
  61 /* read a directory entry from the opened directory */
  62 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  63 {
  64         int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
  65         unsigned int type, clu_offset;
  66         sector_t sector;
  67         struct exfat_chain dir, clu;
  68         struct exfat_uni_name uni_name;
  69         struct exfat_dentry *ep;
  70         struct super_block *sb = inode->i_sb;
  71         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  72         struct exfat_inode_info *ei = EXFAT_I(inode);
  73         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  74         struct buffer_head *bh;
  75
  76         /* check if the given file ID is opened */
  77         if (ei->type != TYPE_DIR)
  78                 return -EPERM;
  79
  80         if (ei->entry == -1)
  81                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  82         else
  83                 exfat_chain_set(&dir, ei->start_clu,
  84                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  85
  86         dentries_per_clu = sbi->dentries_per_clu;
  87         dentries_per_clu_bits = ilog2(dentries_per_clu);
  88
  89         clu_offset = dentry >> dentries_per_clu_bits;
  90         exfat_chain_dup(&clu, &dir);
  91
  92         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  93                 clu.dir += clu_offset;
  94                 clu.size -= clu_offset;
  95         } else {
  96                 /* hint_information */
  97                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
  98                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
  99                         clu_offset -= ei->hint_bmap.off;
 100                         clu.dir = ei->hint_bmap.clu;
 101                 }
 102
 103                 while (clu_offset > 0) {
 104                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 105                                 return -EIO;
 106
 107                         clu_offset--;
 108                 }
 109         }
 110
 111         while (clu.dir != EXFAT_EOF_CLUSTER) {
 112                 i = dentry & (dentries_per_clu - 1);
 113
 114                 for ( ; i < dentries_per_clu; i++, dentry++) {
 115                         ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
 116                         if (!ep)
 117                                 return -EIO;
 118
 119                         type = exfat_get_entry_type(ep);
 120                         if (type == TYPE_UNUSED) {
 121                                 brelse(bh);
 122                                 break;
 123                         }
 124
 125                         if (type != TYPE_FILE && type != TYPE_DIR) {
 126                                 brelse(bh);
 127                                 continue;
 128                         }
 129
 130                         num_ext = ep->dentry.file.num_ext;
 131                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 132                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 133                                         ep->dentry.file.create_tz,
 134                                         ep->dentry.file.create_time,
 135                                         ep->dentry.file.create_date,
 136                                         ep->dentry.file.create_time_cs);
 137                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 138                                         ep->dentry.file.modify_tz,
 139                                         ep->dentry.file.modify_time,
 140                                         ep->dentry.file.modify_date,
 141                                         ep->dentry.file.modify_time_cs);
 142                         exfat_get_entry_time(sbi, &dir_entry->atime,
 143                                         ep->dentry.file.access_tz,
 144                                         ep->dentry.file.access_time,
 145                                         ep->dentry.file.access_date,
 146                                         0);
 147
 148                         *uni_name.name = 0x0;
 149                         exfat_get_uniname_from_ext_entry(sb, &dir, dentry,
 150                                 uni_name.name);
 151                         exfat_utf16_to_nls(sb, &uni_name,
 152                                 dir_entry->namebuf.lfn,
 153                                 dir_entry->namebuf.lfnbuf_len);
 154                         brelse(bh);
 155
 156                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
 157                         if (!ep)
 158                                 return -EIO;
 159                         dir_entry->size =
 160                                 le64_to_cpu(ep->dentry.stream.valid_size);
 161                         dir_entry->entry = dentry;
 162                         brelse(bh);
 163
 164                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
 165                         ei->hint_bmap.clu = clu.dir;
 166
 167                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 168                         return 0;
 169                 }
 170
 171                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 172                         if (--clu.size > 0)
 173                                 clu.dir++;
 174                         else
 175                                 clu.dir = EXFAT_EOF_CLUSTER;
 176                 } else {
 177                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 178                                 return -EIO;
 179                 }
 180         }
 181
 182         dir_entry->namebuf.lfn[0] = '\0';
 183         *cpos = EXFAT_DEN_TO_B(dentry);
 184         return 0;
 185 }
 186
 187 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 188 {
 189         nb->lfn = NULL;
 190         nb->lfnbuf_len = 0;
 191 }
 192
 193 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 194 {
 195         nb->lfn = __getname();
 196         if (!nb->lfn)
 197                 return -ENOMEM;
 198         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 199         return 0;
 200 }
 201
 202 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 203 {
 204         if (!nb->lfn)
 205                 return;
 206
 207         __putname(nb->lfn);
 208         exfat_init_namebuf(nb);
 209 }
 210
 211 /* skip iterating emit_dots when dir is empty */
 212 #define ITER_POS_FILLED_DOTS    (2)
 213 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
 214 {
 215         struct inode *inode = filp->f_path.dentry->d_inode;
 216         struct super_block *sb = inode->i_sb;
 217         struct inode *tmp;
 218         struct exfat_dir_entry de;
 219         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 220         struct exfat_inode_info *ei = EXFAT_I(inode);
 221         unsigned long inum;
 222         loff_t cpos, i_pos;
 223         int err = 0, fake_offset = 0;
 224
 225         exfat_init_namebuf(nb);
 226         mutex_lock(&EXFAT_SB(sb)->s_lock);
 227
 228         cpos = ctx->pos;
 229         if (!dir_emit_dots(filp, ctx))
 230                 goto unlock;
 231
 232         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 233                 cpos = 0;
 234                 fake_offset = 1;
 235         }
 236
 237         if (cpos & (DENTRY_SIZE - 1)) {
 238                 err = -ENOENT;
 239                 goto unlock;
 240         }
 241
 242         /* name buffer should be allocated before use */
 243         err = exfat_alloc_namebuf(nb);
 244         if (err)
 245                 goto unlock;
 246 get_new:
 247         if (cpos >= i_size_read(inode))
 248                 goto end_of_dir;
 249
 250         err = exfat_readdir(inode, &cpos, &de);
 251         if (err) {
 252                 /*
 253                  * At least we tried to read a sector.  Move cpos to next sector
 254                  * position (should be aligned).
 255                  */
 256                 if (err == -EIO) {
 257                         cpos += 1 << (sb->s_blocksize_bits);
 258                         cpos &= ~(sb->s_blocksize - 1);
 259                 }
 260
 261                 err = -EIO;
 262                 goto end_of_dir;
 263         }
 264
 265         if (!nb->lfn[0])
 266                 goto end_of_dir;
 267
 268         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 269         tmp = exfat_iget(sb, i_pos);
 270         if (tmp) {
 271                 inum = tmp->i_ino;
 272                 iput(tmp);
 273         } else {
 274                 inum = iunique(sb, EXFAT_ROOT_INO);
 275         }
 276
 277         /*
 278          * Before calling dir_emit(), sb_lock should be released.
 279          * Because page fault can occur in dir_emit() when the size
 280          * of buffer given from user is larger than one page size.
 281          */
 282         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 283         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 284                         (de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
 285                 goto out_unlocked;
 286         mutex_lock(&EXFAT_SB(sb)->s_lock);
 287         ctx->pos = cpos;
 288         goto get_new;
 289
 290 end_of_dir:
 291         if (!cpos && fake_offset)
 292                 cpos = ITER_POS_FILLED_DOTS;
 293         ctx->pos = cpos;
 294 unlock:
 295         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 296 out_unlocked:
 297         /*
 298          * To improve performance, free namebuf after unlock sb_lock.
 299          * If namebuf is not allocated, this function do nothing
 300          */
 301         exfat_free_namebuf(nb);
 302         return err;
 303 }
 304
 305 const struct file_operations exfat_dir_operations = {
 306         .llseek         = generic_file_llseek,
 307         .read           = generic_read_dir,
 308         .iterate        = exfat_iterate,
 309         .fsync          = exfat_file_fsync,
 310 };
 311
 312 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 313 {
 314         int ret;
 315
 316         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 317
 318         ret = exfat_alloc_cluster(inode, 1, clu);
 319         if (ret)
 320                 return ret;
 321
 322         return exfat_zeroed_cluster(inode, clu->dir);
 323 }
 324
 325 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 326 {
 327         int len;
 328
 329         len = p_uniname->name_len;
 330         if (len == 0)
 331                 return -EINVAL;
 332
 333         /* 1 file entry + 1 stream entry + name entries */
 334         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 335 }
 336
 337 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 338 {
 339         if (ep->type == EXFAT_UNUSED)
 340                 return TYPE_UNUSED;
 341         if (IS_EXFAT_DELETED(ep->type))
 342                 return TYPE_DELETED;
 343         if (ep->type == EXFAT_INVAL)
 344                 return TYPE_INVALID;
 345         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 346                 if (ep->type == EXFAT_BITMAP)
 347                         return TYPE_BITMAP;
 348                 if (ep->type == EXFAT_UPCASE)
 349                         return TYPE_UPCASE;
 350                 if (ep->type == EXFAT_VOLUME)
 351                         return TYPE_VOLUME;
 352                 if (ep->type == EXFAT_FILE) {
 353                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 354                                 return TYPE_DIR;
 355                         return TYPE_FILE;
 356                 }
 357                 return TYPE_CRITICAL_PRI;
 358         }
 359         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 360                 if (ep->type == EXFAT_GUID)
 361                         return TYPE_GUID;
 362                 if (ep->type == EXFAT_PADDING)
 363                         return TYPE_PADDING;
 364                 if (ep->type == EXFAT_ACLTAB)
 365                         return TYPE_ACLTAB;
 366                 return TYPE_BENIGN_PRI;
 367         }
 368         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 369                 if (ep->type == EXFAT_STREAM)
 370                         return TYPE_STREAM;
 371                 if (ep->type == EXFAT_NAME)
 372                         return TYPE_EXTEND;
 373                 if (ep->type == EXFAT_ACL)
 374                         return TYPE_ACL;
 375                 return TYPE_CRITICAL_SEC;
 376         }
 377         return TYPE_BENIGN_SEC;
 378 }
 379
 380 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 381 {
 382         if (type == TYPE_UNUSED) {
 383                 ep->type = EXFAT_UNUSED;
 384         } else if (type == TYPE_DELETED) {
 385                 ep->type &= EXFAT_DELETE;
 386         } else if (type == TYPE_STREAM) {
 387                 ep->type = EXFAT_STREAM;
 388         } else if (type == TYPE_EXTEND) {
 389                 ep->type = EXFAT_NAME;
 390         } else if (type == TYPE_BITMAP) {
 391                 ep->type = EXFAT_BITMAP;
 392         } else if (type == TYPE_UPCASE) {
 393                 ep->type = EXFAT_UPCASE;
 394         } else if (type == TYPE_VOLUME) {
 395                 ep->type = EXFAT_VOLUME;
 396         } else if (type == TYPE_DIR) {
 397                 ep->type = EXFAT_FILE;
 398                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 399         } else if (type == TYPE_FILE) {
 400                 ep->type = EXFAT_FILE;
 401                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 402         }
 403 }
 404
 405 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 406                 unsigned char flags, unsigned int start_clu,
 407                 unsigned long long size)
 408 {
 409         exfat_set_entry_type(ep, TYPE_STREAM);
 410         ep->dentry.stream.flags = flags;
 411         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 412         ep->dentry.stream.valid_size = cpu_to_le64(size);
 413         ep->dentry.stream.size = cpu_to_le64(size);
 414 }
 415
 416 static void exfat_init_name_entry(struct exfat_dentry *ep,
 417                 unsigned short *uniname)
 418 {
 419         int i;
 420
 421         exfat_set_entry_type(ep, TYPE_EXTEND);
 422         ep->dentry.name.flags = 0x0;
 423
 424         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 425                 if (*uniname != 0x0) {
 426                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 427                         uniname++;
 428                 } else {
 429                         ep->dentry.name.unicode_0_14[i] = 0x0;
 430                 }
 431         }
 432 }
 433
 434 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 435                 int entry, unsigned int type, unsigned int start_clu,
 436                 unsigned long long size)
 437 {
 438         struct super_block *sb = inode->i_sb;
 439         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 440         struct timespec64 ts = current_time(inode);
 441         sector_t sector;
 442         struct exfat_dentry *ep;
 443         struct buffer_head *bh;
 444
 445         /*
 446          * We cannot use exfat_get_dentry_set here because file ep is not
 447          * initialized yet.
 448          */
 449         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 450         if (!ep)
 451                 return -EIO;
 452
 453         exfat_set_entry_type(ep, type);
 454         exfat_set_entry_time(sbi, &ts,
 455                         &ep->dentry.file.create_tz,
 456                         &ep->dentry.file.create_time,
 457                         &ep->dentry.file.create_date,
 458                         &ep->dentry.file.create_time_cs);
 459         exfat_set_entry_time(sbi, &ts,
 460                         &ep->dentry.file.modify_tz,
 461                         &ep->dentry.file.modify_time,
 462                         &ep->dentry.file.modify_date,
 463                         &ep->dentry.file.modify_time_cs);
 464         exfat_set_entry_time(sbi, &ts,
 465                         &ep->dentry.file.access_tz,
 466                         &ep->dentry.file.access_time,
 467                         &ep->dentry.file.access_date,
 468                         NULL);
 469
 470         exfat_update_bh(bh, IS_DIRSYNC(inode));
 471         brelse(bh);
 472
 473         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 474         if (!ep)
 475                 return -EIO;
 476
 477         exfat_init_stream_entry(ep,
 478                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 479                 start_clu, size);
 480         exfat_update_bh(bh, IS_DIRSYNC(inode));
 481         brelse(bh);
 482
 483         return 0;
 484 }
 485
 486 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 487                 int entry)
 488 {
 489         struct super_block *sb = inode->i_sb;
 490         int ret = 0;
 491         int i, num_entries;
 492         sector_t sector;
 493         u16 chksum;
 494         struct exfat_dentry *ep, *fep;
 495         struct buffer_head *fbh, *bh;
 496
 497         fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
 498         if (!fep)
 499                 return -EIO;
 500
 501         num_entries = fep->dentry.file.num_ext + 1;
 502         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 503
 504         for (i = 1; i < num_entries; i++) {
 505                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
 506                 if (!ep) {
 507                         ret = -EIO;
 508                         goto release_fbh;
 509                 }
 510                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 511                                 CS_DEFAULT);
 512                 brelse(bh);
 513         }
 514
 515         fep->dentry.file.checksum = cpu_to_le16(chksum);
 516         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 517 release_fbh:
 518         brelse(fbh);
 519         return ret;
 520 }
 521
 522 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 523                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 524 {
 525         struct super_block *sb = inode->i_sb;
 526         int i;
 527         sector_t sector;
 528         unsigned short *uniname = p_uniname->name;
 529         struct exfat_dentry *ep;
 530         struct buffer_head *bh;
 531         int sync = IS_DIRSYNC(inode);
 532
 533         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 534         if (!ep)
 535                 return -EIO;
 536
 537         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 538         exfat_update_bh(bh, sync);
 539         brelse(bh);
 540
 541         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 542         if (!ep)
 543                 return -EIO;
 544
 545         ep->dentry.stream.name_len = p_uniname->name_len;
 546         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 547         exfat_update_bh(bh, sync);
 548         brelse(bh);
 549
 550         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
 551                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 552                 if (!ep)
 553                         return -EIO;
 554
 555                 exfat_init_name_entry(ep, uniname);
 556                 exfat_update_bh(bh, sync);
 557                 brelse(bh);
 558                 uniname += EXFAT_FILE_NAME_LEN;
 559         }
 560
 561         exfat_update_dir_chksum(inode, p_dir, entry);
 562         return 0;
 563 }
 564
 565 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 566                 int entry, int order, int num_entries)
 567 {
 568         struct super_block *sb = inode->i_sb;
 569         int i;
 570         sector_t sector;
 571         struct exfat_dentry *ep;
 572         struct buffer_head *bh;
 573
 574         for (i = order; i < num_entries; i++) {
 575                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 576                 if (!ep)
 577                         return -EIO;
 578
 579                 exfat_set_entry_type(ep, TYPE_DELETED);
 580                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 581                 brelse(bh);
 582         }
 583
 584         return 0;
 585 }
 586
 587 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 588 {
 589         int chksum_type = CS_DIR_ENTRY, i;
 590         unsigned short chksum = 0;
 591         struct exfat_dentry *ep;
 592
 593         for (i = 0; i < es->num_entries; i++) {
 594                 ep = exfat_get_dentry_cached(es, i);
 595                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 596                                              chksum_type);
 597                 chksum_type = CS_DEFAULT;
 598         }
 599         ep = exfat_get_dentry_cached(es, 0);
 600         ep->dentry.file.checksum = cpu_to_le16(chksum);
 601         es->modified = true;
 602 }
 603
 604 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 605 {
 606         int i, err = 0;
 607
 608         if (es->modified)
 609                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 610
 611         for (i = 0; i < es->num_bh; i++)
 612                 if (err)
 613                         bforget(es->bh[i]);
 614                 else
 615                         brelse(es->bh[i]);
 616         kfree(es);
 617         return err;
 618 }
 619
 620 static int exfat_walk_fat_chain(struct super_block *sb,
 621                 struct exfat_chain *p_dir, unsigned int byte_offset,
 622                 unsigned int *clu)
 623 {
 624         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 625         unsigned int clu_offset;
 626         unsigned int cur_clu;
 627
 628         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 629         cur_clu = p_dir->dir;
 630
 631         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 632                 cur_clu += clu_offset;
 633         } else {
 634                 while (clu_offset > 0) {
 635                         if (exfat_get_next_cluster(sb, &cur_clu))
 636                                 return -EIO;
 637                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 638                                 exfat_fs_error(sb,
 639                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 640                                         p_dir->dir,
 641                                         EXFAT_B_TO_DEN(byte_offset));
 642                                 return -EIO;
 643                         }
 644                         clu_offset--;
 645                 }
 646         }
 647
 648         *clu = cur_clu;
 649         return 0;
 650 }
 651
 652 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 653                 int entry, sector_t *sector, int *offset)
 654 {
 655         int ret;
 656         unsigned int off, clu = 0;
 657         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 658
 659         off = EXFAT_DEN_TO_B(entry);
 660
 661         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 662         if (ret)
 663                 return ret;
 664
 665         /* byte offset in cluster */
 666         off = EXFAT_CLU_OFFSET(off, sbi);
 667
 668         /* byte offset in sector    */
 669         *offset = EXFAT_BLK_OFFSET(off, sb);
 670
 671         /* sector offset in cluster */
 672         *sector = EXFAT_B_TO_BLK(off, sb);
 673         *sector += exfat_cluster_to_sector(sbi, clu);
 674         return 0;
 675 }
 676
 677 #define EXFAT_MAX_RA_SIZE     (128*1024)
 678 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 679 {
 680         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 681         struct buffer_head *bh;
 682         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 683         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 684         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 685         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 686
 687         /* Read-ahead is not required */
 688         if (sbi->sect_per_clus == 1)
 689                 return 0;
 690
 691         if (sec < sbi->data_start_sector) {
 692                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 693                           (unsigned long long)sec, sbi->data_start_sector);
 694                 return -EIO;
 695         }
 696
 697         /* Not sector aligned with ra_count, resize ra_count to page size */
 698         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 699                 ra_count = page_ra_count;
 700
 701         bh = sb_find_get_block(sb, sec);
 702         if (!bh || !buffer_uptodate(bh)) {
 703                 unsigned int i;
 704
 705                 for (i = 0; i < ra_count; i++)
 706                         sb_breadahead(sb, (sector_t)(sec + i));
 707         }
 708         brelse(bh);
 709         return 0;
 710 }
 711
 712 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 713                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 714                 sector_t *sector)
 715 {
 716         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 717         int off;
 718         sector_t sec;
 719
 720         if (p_dir->dir == DIR_DELETED) {
 721                 exfat_err(sb, "abnormal access to deleted dentry");
 722                 return NULL;
 723         }
 724
 725         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 726                 return NULL;
 727
 728         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 729                         !(entry & (dentries_per_page - 1)))
 730                 exfat_dir_readahead(sb, sec);
 731
 732         *bh = sb_bread(sb, sec);
 733         if (!*bh)
 734                 return NULL;
 735
 736         if (sector)
 737                 *sector = sec;
 738         return (struct exfat_dentry *)((*bh)->b_data + off);
 739 }
 740
 741 enum exfat_validate_dentry_mode {
 742         ES_MODE_STARTED,
 743         ES_MODE_GET_FILE_ENTRY,
 744         ES_MODE_GET_STRM_ENTRY,
 745         ES_MODE_GET_NAME_ENTRY,
 746         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 747 };
 748
 749 static bool exfat_validate_entry(unsigned int type,
 750                 enum exfat_validate_dentry_mode *mode)
 751 {
 752         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 753                 return false;
 754
 755         switch (*mode) {
 756         case ES_MODE_STARTED:
 757                 if  (type != TYPE_FILE && type != TYPE_DIR)
 758                         return false;
 759                 *mode = ES_MODE_GET_FILE_ENTRY;
 760                 return true;
 761         case ES_MODE_GET_FILE_ENTRY:
 762                 if (type != TYPE_STREAM)
 763                         return false;
 764                 *mode = ES_MODE_GET_STRM_ENTRY;
 765                 return true;
 766         case ES_MODE_GET_STRM_ENTRY:
 767                 if (type != TYPE_EXTEND)
 768                         return false;
 769                 *mode = ES_MODE_GET_NAME_ENTRY;
 770                 return true;
 771         case ES_MODE_GET_NAME_ENTRY:
 772                 if (type == TYPE_STREAM)
 773                         return false;
 774                 if (type != TYPE_EXTEND) {
 775                         if (!(type & TYPE_CRITICAL_SEC))
 776                                 return false;
 777                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 778                 }
 779                 return true;
 780         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 781                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 782                         return false;
 783                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 784                         return false;
 785                 return true;
 786         default:
 787                 WARN_ON_ONCE(1);
 788                 return false;
 789         }
 790 }
 791
 792 struct exfat_dentry *exfat_get_dentry_cached(
 793         struct exfat_entry_set_cache *es, int num)
 794 {
 795         int off = es->start_off + num * DENTRY_SIZE;
 796         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 797         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 798
 799         return (struct exfat_dentry *)p;
 800 }
 801
 802 /*
 803  * Returns a set of dentries for a file or dir.
 804  *
 805  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 806  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 807  * changes made in this entry set to the real device.
 808  *
 809  * in:
 810  *   sb+p_dir+entry: indicates a file/dir
 811  *   type:  specifies how many dentries should be included.
 812  * return:
 813  *   pointer of entry set on success,
 814  *   NULL on failure.
 815  */
 816 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 817                 struct exfat_chain *p_dir, int entry, unsigned int type)
 818 {
 819         int ret, i, num_bh;
 820         unsigned int off, byte_offset, clu = 0;
 821         sector_t sec;
 822         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 823         struct exfat_entry_set_cache *es;
 824         struct exfat_dentry *ep;
 825         int num_entries;
 826         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 827         struct buffer_head *bh;
 828
 829         if (p_dir->dir == DIR_DELETED) {
 830                 exfat_err(sb, "access to deleted dentry");
 831                 return NULL;
 832         }
 833
 834         byte_offset = EXFAT_DEN_TO_B(entry);
 835         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
 836         if (ret)
 837                 return NULL;
 838
 839         es = kzalloc(sizeof(*es), GFP_KERNEL);
 840         if (!es)
 841                 return NULL;
 842         es->sb = sb;
 843         es->modified = false;
 844
 845         /* byte offset in cluster */
 846         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 847
 848         /* byte offset in sector */
 849         off = EXFAT_BLK_OFFSET(byte_offset, sb);
 850         es->start_off = off;
 851
 852         /* sector offset in cluster */
 853         sec = EXFAT_B_TO_BLK(byte_offset, sb);
 854         sec += exfat_cluster_to_sector(sbi, clu);
 855
 856         bh = sb_bread(sb, sec);
 857         if (!bh)
 858                 goto free_es;
 859         es->bh[es->num_bh++] = bh;
 860
 861         ep = exfat_get_dentry_cached(es, 0);
 862         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 863                 goto free_es;
 864
 865         num_entries = type == ES_ALL_ENTRIES ?
 866                 ep->dentry.file.num_ext + 1 : type;
 867         es->num_entries = num_entries;
 868
 869         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 870         for (i = 1; i < num_bh; i++) {
 871                 /* get the next sector */
 872                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 873                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 874                                 clu++;
 875                         else if (exfat_get_next_cluster(sb, &clu))
 876                                 goto free_es;
 877                         sec = exfat_cluster_to_sector(sbi, clu);
 878                 } else {
 879                         sec++;
 880                 }
 881
 882                 bh = sb_bread(sb, sec);
 883                 if (!bh)
 884                         goto free_es;
 885                 es->bh[es->num_bh++] = bh;
 886         }
 887
 888         /* validiate cached dentries */
 889         for (i = 1; i < num_entries; i++) {
 890                 ep = exfat_get_dentry_cached(es, i);
 891                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 892                         goto free_es;
 893         }
 894         return es;
 895
 896 free_es:
 897         exfat_free_dentry_set(es, false);
 898         return NULL;
 899 }
 900
 901 enum {
 902         DIRENT_STEP_FILE,
 903         DIRENT_STEP_STRM,
 904         DIRENT_STEP_NAME,
 905         DIRENT_STEP_SECD,
 906 };
 907
 908 /*
 909  * return values:
 910  *   >= 0       : return dir entiry position with the name in dir
 911  *   -ENOENT    : entry with the name does not exist
 912  *   -EIO       : I/O error
 913  */
 914 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 915                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 916                 int num_entries, unsigned int type)
 917 {
 918         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 919         int order, step, name_len = 0;
 920         int dentries_per_clu, num_empty = 0;
 921         unsigned int entry_type;
 922         unsigned short *uniname = NULL;
 923         struct exfat_chain clu;
 924         struct exfat_hint *hint_stat = &ei->hint_stat;
 925         struct exfat_hint_femp candi_empty;
 926         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 927
 928         dentries_per_clu = sbi->dentries_per_clu;
 929
 930         exfat_chain_dup(&clu, p_dir);
 931
 932         if (hint_stat->eidx) {
 933                 clu.dir = hint_stat->clu;
 934                 dentry = hint_stat->eidx;
 935                 end_eidx = dentry;
 936         }
 937
 938         candi_empty.eidx = EXFAT_HINT_NONE;
 939 rewind:
 940         order = 0;
 941         step = DIRENT_STEP_FILE;
 942         while (clu.dir != EXFAT_EOF_CLUSTER) {
 943                 i = dentry & (dentries_per_clu - 1);
 944                 for (; i < dentries_per_clu; i++, dentry++) {
 945                         struct exfat_dentry *ep;
 946                         struct buffer_head *bh;
 947
 948                         if (rewind && dentry == end_eidx)
 949                                 goto not_found;
 950
 951                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
 952                         if (!ep)
 953                                 return -EIO;
 954
 955                         entry_type = exfat_get_entry_type(ep);
 956
 957                         if (entry_type == TYPE_UNUSED ||
 958                             entry_type == TYPE_DELETED) {
 959                                 step = DIRENT_STEP_FILE;
 960
 961                                 num_empty++;
 962                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 963                                                 num_empty == 1) {
 964                                         exfat_chain_set(&candi_empty.cur,
 965                                                 clu.dir, clu.size, clu.flags);
 966                                 }
 967
 968                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 969                                                 num_empty >= num_entries) {
 970                                         candi_empty.eidx =
 971                                                 dentry - (num_empty - 1);
 972                                         WARN_ON(candi_empty.eidx < 0);
 973                                         candi_empty.count = num_empty;
 974
 975                                         if (ei->hint_femp.eidx ==
 976                                                         EXFAT_HINT_NONE ||
 977                                                 candi_empty.eidx <=
 978                                                          ei->hint_femp.eidx)
 979                                                 ei->hint_femp = candi_empty;
 980                                 }
 981
 982                                 brelse(bh);
 983                                 if (entry_type == TYPE_UNUSED)
 984                                         goto not_found;
 985                                 continue;
 986                         }
 987
 988                         num_empty = 0;
 989                         candi_empty.eidx = EXFAT_HINT_NONE;
 990
 991                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
 992                                 step = DIRENT_STEP_FILE;
 993                                 if (type == TYPE_ALL || type == entry_type) {
 994                                         num_ext = ep->dentry.file.num_ext;
 995                                         step = DIRENT_STEP_STRM;
 996                                 }
 997                                 brelse(bh);
 998                                 continue;
 999                         }
1000
1001                         if (entry_type == TYPE_STREAM) {
1002                                 u16 name_hash;
1003
1004                                 if (step != DIRENT_STEP_STRM) {
1005                                         step = DIRENT_STEP_FILE;
1006                                         brelse(bh);
1007                                         continue;
1008                                 }
1009                                 step = DIRENT_STEP_FILE;
1010                                 name_hash = le16_to_cpu(
1011                                                 ep->dentry.stream.name_hash);
1012                                 if (p_uniname->name_hash == name_hash &&
1013                                     p_uniname->name_len ==
1014                                                 ep->dentry.stream.name_len) {
1015                                         step = DIRENT_STEP_NAME;
1016                                         order = 1;
1017                                         name_len = 0;
1018                                 }
1019                                 brelse(bh);
1020                                 continue;
1021                         }
1022
1023                         brelse(bh);
1024                         if (entry_type == TYPE_EXTEND) {
1025                                 unsigned short entry_uniname[16], unichar;
1026
1027                                 if (step != DIRENT_STEP_NAME) {
1028                                         step = DIRENT_STEP_FILE;
1029                                         continue;
1030                                 }
1031
1032                                 if (++order == 2)
1033                                         uniname = p_uniname->name;
1034                                 else
1035                                         uniname += EXFAT_FILE_NAME_LEN;
1036
1037                                 len = exfat_extract_uni_name(ep, entry_uniname);
1038                                 name_len += len;
1039
1040                                 unichar = *(uniname+len);
1041                                 *(uniname+len) = 0x0;
1042
1043                                 if (exfat_uniname_ncmp(sb, uniname,
1044                                         entry_uniname, len)) {
1045                                         step = DIRENT_STEP_FILE;
1046                                 } else if (p_uniname->name_len == name_len) {
1047                                         if (order == num_ext)
1048                                                 goto found;
1049                                         step = DIRENT_STEP_SECD;
1050                                 }
1051
1052                                 *(uniname+len) = unichar;
1053                                 continue;
1054                         }
1055
1056                         if (entry_type &
1057                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1058                                 if (step == DIRENT_STEP_SECD) {
1059                                         if (++order == num_ext)
1060                                                 goto found;
1061                                         continue;
1062                                 }
1063                         }
1064                         step = DIRENT_STEP_FILE;
1065                 }
1066
1067                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1068                         if (--clu.size > 0)
1069                                 clu.dir++;
1070                         else
1071                                 clu.dir = EXFAT_EOF_CLUSTER;
1072                 } else {
1073                         if (exfat_get_next_cluster(sb, &clu.dir))
1074                                 return -EIO;
1075                 }
1076         }
1077
1078 not_found:
1079         /*
1080          * We started at not 0 index,so we should try to find target
1081          * from 0 index to the index we started at.
1082          */
1083         if (!rewind && end_eidx) {
1084                 rewind = 1;
1085                 dentry = 0;
1086                 clu.dir = p_dir->dir;
1087                 /* reset empty hint */
1088                 num_empty = 0;
1089                 candi_empty.eidx = EXFAT_HINT_NONE;
1090                 goto rewind;
1091         }
1092
1093         /* initialized hint_stat */
1094         hint_stat->clu = p_dir->dir;
1095         hint_stat->eidx = 0;
1096         return -ENOENT;
1097
1098 found:
1099         /* next dentry we'll find is out of this cluster */
1100         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1101                 int ret = 0;
1102
1103                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1104                         if (--clu.size > 0)
1105                                 clu.dir++;
1106                         else
1107                                 clu.dir = EXFAT_EOF_CLUSTER;
1108                 } else {
1109                         ret = exfat_get_next_cluster(sb, &clu.dir);
1110                 }
1111
1112                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1113                         /* just initialized hint_stat */
1114                         hint_stat->clu = p_dir->dir;
1115                         hint_stat->eidx = 0;
1116                         return (dentry - num_ext);
1117                 }
1118         }
1119
1120         hint_stat->clu = clu.dir;
1121         hint_stat->eidx = dentry + 1;
1122         return dentry - num_ext;
1123 }
1124
1125 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1126                 int entry, struct exfat_dentry *ep)
1127 {
1128         int i, count = 0;
1129         unsigned int type;
1130         struct exfat_dentry *ext_ep;
1131         struct buffer_head *bh;
1132
1133         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1134                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
1135                 if (!ext_ep)
1136                         return -EIO;
1137
1138                 type = exfat_get_entry_type(ext_ep);
1139                 brelse(bh);
1140                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1141                         count++;
1142                 else
1143                         break;
1144         }
1145         return count;
1146 }
1147
1148 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1149 {
1150         int i, count = 0;
1151         int dentries_per_clu;
1152         unsigned int entry_type;
1153         struct exfat_chain clu;
1154         struct exfat_dentry *ep;
1155         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1156         struct buffer_head *bh;
1157
1158         dentries_per_clu = sbi->dentries_per_clu;
1159
1160         exfat_chain_dup(&clu, p_dir);
1161
1162         while (clu.dir != EXFAT_EOF_CLUSTER) {
1163                 for (i = 0; i < dentries_per_clu; i++) {
1164                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
1165                         if (!ep)
1166                                 return -EIO;
1167                         entry_type = exfat_get_entry_type(ep);
1168                         brelse(bh);
1169
1170                         if (entry_type == TYPE_UNUSED)
1171                                 return count;
1172                         if (entry_type != TYPE_DIR)
1173                                 continue;
1174                         count++;
1175                 }
1176
1177                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1178                         if (--clu.size > 0)
1179                                 clu.dir++;
1180                         else
1181                                 clu.dir = EXFAT_EOF_CLUSTER;
1182                 } else {
1183                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1184                                 return -EIO;
1185                 }
1186         }
1187
1188         return count;
1189 }