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, max_dentries;
  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         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  89                                            (u64)sbi->num_clusters << dentries_per_clu_bits);
  90
  91         clu_offset = dentry >> dentries_per_clu_bits;
  92         exfat_chain_dup(&clu, &dir);
  93
  94         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  95                 clu.dir += clu_offset;
  96                 clu.size -= clu_offset;
  97         } else {
  98                 /* hint_information */
  99                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
 100                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 101                         clu_offset -= ei->hint_bmap.off;
 102                         clu.dir = ei->hint_bmap.clu;
 103                 }
 104
 105                 while (clu_offset > 0) {
 106                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 107                                 return -EIO;
 108
 109                         clu_offset--;
 110                 }
 111         }
 112
 113         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
 114                 i = dentry & (dentries_per_clu - 1);
 115
 116                 for ( ; i < dentries_per_clu; i++, dentry++) {
 117                         ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
 118                         if (!ep)
 119                                 return -EIO;
 120
 121                         type = exfat_get_entry_type(ep);
 122                         if (type == TYPE_UNUSED) {
 123                                 brelse(bh);
 124                                 break;
 125                         }
 126
 127                         if (type != TYPE_FILE && type != TYPE_DIR) {
 128                                 brelse(bh);
 129                                 continue;
 130                         }
 131
 132                         num_ext = ep->dentry.file.num_ext;
 133                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 134                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 135                                         ep->dentry.file.create_tz,
 136                                         ep->dentry.file.create_time,
 137                                         ep->dentry.file.create_date,
 138                                         ep->dentry.file.create_time_cs);
 139                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 140                                         ep->dentry.file.modify_tz,
 141                                         ep->dentry.file.modify_time,
 142                                         ep->dentry.file.modify_date,
 143                                         ep->dentry.file.modify_time_cs);
 144                         exfat_get_entry_time(sbi, &dir_entry->atime,
 145                                         ep->dentry.file.access_tz,
 146                                         ep->dentry.file.access_time,
 147                                         ep->dentry.file.access_date,
 148                                         0);
 149
 150                         *uni_name.name = 0x0;
 151                         exfat_get_uniname_from_ext_entry(sb, &dir, dentry,
 152                                 uni_name.name);
 153                         exfat_utf16_to_nls(sb, &uni_name,
 154                                 dir_entry->namebuf.lfn,
 155                                 dir_entry->namebuf.lfnbuf_len);
 156                         brelse(bh);
 157
 158                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
 159                         if (!ep)
 160                                 return -EIO;
 161                         dir_entry->size =
 162                                 le64_to_cpu(ep->dentry.stream.valid_size);
 163                         dir_entry->entry = dentry;
 164                         brelse(bh);
 165
 166                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
 167                         ei->hint_bmap.clu = clu.dir;
 168
 169                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 170                         return 0;
 171                 }
 172
 173                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 174                         if (--clu.size > 0)
 175                                 clu.dir++;
 176                         else
 177                                 clu.dir = EXFAT_EOF_CLUSTER;
 178                 } else {
 179                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 180                                 return -EIO;
 181                 }
 182         }
 183
 184         dir_entry->namebuf.lfn[0] = '\0';
 185         *cpos = EXFAT_DEN_TO_B(dentry);
 186         return 0;
 187 }
 188
 189 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 190 {
 191         nb->lfn = NULL;
 192         nb->lfnbuf_len = 0;
 193 }
 194
 195 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 196 {
 197         nb->lfn = __getname();
 198         if (!nb->lfn)
 199                 return -ENOMEM;
 200         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 201         return 0;
 202 }
 203
 204 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 205 {
 206         if (!nb->lfn)
 207                 return;
 208
 209         __putname(nb->lfn);
 210         exfat_init_namebuf(nb);
 211 }
 212
 213 /* skip iterating emit_dots when dir is empty */
 214 #define ITER_POS_FILLED_DOTS    (2)
 215 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
 216 {
 217         struct inode *inode = filp->f_path.dentry->d_inode;
 218         struct super_block *sb = inode->i_sb;
 219         struct inode *tmp;
 220         struct exfat_dir_entry de;
 221         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 222         struct exfat_inode_info *ei = EXFAT_I(inode);
 223         unsigned long inum;
 224         loff_t cpos, i_pos;
 225         int err = 0, fake_offset = 0;
 226
 227         exfat_init_namebuf(nb);
 228         mutex_lock(&EXFAT_SB(sb)->s_lock);
 229
 230         cpos = ctx->pos;
 231         if (!dir_emit_dots(filp, ctx))
 232                 goto unlock;
 233
 234         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 235                 cpos = 0;
 236                 fake_offset = 1;
 237         }
 238
 239         if (cpos & (DENTRY_SIZE - 1)) {
 240                 err = -ENOENT;
 241                 goto unlock;
 242         }
 243
 244         /* name buffer should be allocated before use */
 245         err = exfat_alloc_namebuf(nb);
 246         if (err)
 247                 goto unlock;
 248 get_new:
 249         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 250                 goto end_of_dir;
 251
 252         err = exfat_readdir(inode, &cpos, &de);
 253         if (err) {
 254                 /*
 255                  * At least we tried to read a sector.  Move cpos to next sector
 256                  * position (should be aligned).
 257                  */
 258                 if (err == -EIO) {
 259                         cpos += 1 << (sb->s_blocksize_bits);
 260                         cpos &= ~(sb->s_blocksize - 1);
 261                 }
 262
 263                 err = -EIO;
 264                 goto end_of_dir;
 265         }
 266
 267         if (!nb->lfn[0])
 268                 goto end_of_dir;
 269
 270         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 271         tmp = exfat_iget(sb, i_pos);
 272         if (tmp) {
 273                 inum = tmp->i_ino;
 274                 iput(tmp);
 275         } else {
 276                 inum = iunique(sb, EXFAT_ROOT_INO);
 277         }
 278
 279         /*
 280          * Before calling dir_emit(), sb_lock should be released.
 281          * Because page fault can occur in dir_emit() when the size
 282          * of buffer given from user is larger than one page size.
 283          */
 284         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 285         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 286                         (de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
 287                 goto out_unlocked;
 288         mutex_lock(&EXFAT_SB(sb)->s_lock);
 289         ctx->pos = cpos;
 290         goto get_new;
 291
 292 end_of_dir:
 293         if (!cpos && fake_offset)
 294                 cpos = ITER_POS_FILLED_DOTS;
 295         ctx->pos = cpos;
 296 unlock:
 297         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 298 out_unlocked:
 299         /*
 300          * To improve performance, free namebuf after unlock sb_lock.
 301          * If namebuf is not allocated, this function do nothing
 302          */
 303         exfat_free_namebuf(nb);
 304         return err;
 305 }
 306
 307 const struct file_operations exfat_dir_operations = {
 308         .llseek         = generic_file_llseek,
 309         .read           = generic_read_dir,
 310         .iterate        = exfat_iterate,
 311         .fsync          = exfat_file_fsync,
 312 };
 313
 314 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 315 {
 316         int ret;
 317
 318         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 319
 320         ret = exfat_alloc_cluster(inode, 1, clu);
 321         if (ret)
 322                 return ret;
 323
 324         return exfat_zeroed_cluster(inode, clu->dir);
 325 }
 326
 327 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 328 {
 329         int len;
 330
 331         len = p_uniname->name_len;
 332         if (len == 0)
 333                 return -EINVAL;
 334
 335         /* 1 file entry + 1 stream entry + name entries */
 336         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 337 }
 338
 339 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 340 {
 341         if (ep->type == EXFAT_UNUSED)
 342                 return TYPE_UNUSED;
 343         if (IS_EXFAT_DELETED(ep->type))
 344                 return TYPE_DELETED;
 345         if (ep->type == EXFAT_INVAL)
 346                 return TYPE_INVALID;
 347         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 348                 if (ep->type == EXFAT_BITMAP)
 349                         return TYPE_BITMAP;
 350                 if (ep->type == EXFAT_UPCASE)
 351                         return TYPE_UPCASE;
 352                 if (ep->type == EXFAT_VOLUME)
 353                         return TYPE_VOLUME;
 354                 if (ep->type == EXFAT_FILE) {
 355                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 356                                 return TYPE_DIR;
 357                         return TYPE_FILE;
 358                 }
 359                 return TYPE_CRITICAL_PRI;
 360         }
 361         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 362                 if (ep->type == EXFAT_GUID)
 363                         return TYPE_GUID;
 364                 if (ep->type == EXFAT_PADDING)
 365                         return TYPE_PADDING;
 366                 if (ep->type == EXFAT_ACLTAB)
 367                         return TYPE_ACLTAB;
 368                 return TYPE_BENIGN_PRI;
 369         }
 370         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 371                 if (ep->type == EXFAT_STREAM)
 372                         return TYPE_STREAM;
 373                 if (ep->type == EXFAT_NAME)
 374                         return TYPE_EXTEND;
 375                 if (ep->type == EXFAT_ACL)
 376                         return TYPE_ACL;
 377                 return TYPE_CRITICAL_SEC;
 378         }
 379         return TYPE_BENIGN_SEC;
 380 }
 381
 382 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 383 {
 384         if (type == TYPE_UNUSED) {
 385                 ep->type = EXFAT_UNUSED;
 386         } else if (type == TYPE_DELETED) {
 387                 ep->type &= EXFAT_DELETE;
 388         } else if (type == TYPE_STREAM) {
 389                 ep->type = EXFAT_STREAM;
 390         } else if (type == TYPE_EXTEND) {
 391                 ep->type = EXFAT_NAME;
 392         } else if (type == TYPE_BITMAP) {
 393                 ep->type = EXFAT_BITMAP;
 394         } else if (type == TYPE_UPCASE) {
 395                 ep->type = EXFAT_UPCASE;
 396         } else if (type == TYPE_VOLUME) {
 397                 ep->type = EXFAT_VOLUME;
 398         } else if (type == TYPE_DIR) {
 399                 ep->type = EXFAT_FILE;
 400                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 401         } else if (type == TYPE_FILE) {
 402                 ep->type = EXFAT_FILE;
 403                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 404         }
 405 }
 406
 407 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 408                 unsigned char flags, unsigned int start_clu,
 409                 unsigned long long size)
 410 {
 411         exfat_set_entry_type(ep, TYPE_STREAM);
 412         ep->dentry.stream.flags = flags;
 413         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 414         ep->dentry.stream.valid_size = cpu_to_le64(size);
 415         ep->dentry.stream.size = cpu_to_le64(size);
 416 }
 417
 418 static void exfat_init_name_entry(struct exfat_dentry *ep,
 419                 unsigned short *uniname)
 420 {
 421         int i;
 422
 423         exfat_set_entry_type(ep, TYPE_EXTEND);
 424         ep->dentry.name.flags = 0x0;
 425
 426         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 427                 if (*uniname != 0x0) {
 428                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 429                         uniname++;
 430                 } else {
 431                         ep->dentry.name.unicode_0_14[i] = 0x0;
 432                 }
 433         }
 434 }
 435
 436 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 437                 int entry, unsigned int type, unsigned int start_clu,
 438                 unsigned long long size)
 439 {
 440         struct super_block *sb = inode->i_sb;
 441         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 442         struct timespec64 ts = current_time(inode);
 443         sector_t sector;
 444         struct exfat_dentry *ep;
 445         struct buffer_head *bh;
 446
 447         /*
 448          * We cannot use exfat_get_dentry_set here because file ep is not
 449          * initialized yet.
 450          */
 451         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 452         if (!ep)
 453                 return -EIO;
 454
 455         exfat_set_entry_type(ep, type);
 456         exfat_set_entry_time(sbi, &ts,
 457                         &ep->dentry.file.create_tz,
 458                         &ep->dentry.file.create_time,
 459                         &ep->dentry.file.create_date,
 460                         &ep->dentry.file.create_time_cs);
 461         exfat_set_entry_time(sbi, &ts,
 462                         &ep->dentry.file.modify_tz,
 463                         &ep->dentry.file.modify_time,
 464                         &ep->dentry.file.modify_date,
 465                         &ep->dentry.file.modify_time_cs);
 466         exfat_set_entry_time(sbi, &ts,
 467                         &ep->dentry.file.access_tz,
 468                         &ep->dentry.file.access_time,
 469                         &ep->dentry.file.access_date,
 470                         NULL);
 471
 472         exfat_update_bh(bh, IS_DIRSYNC(inode));
 473         brelse(bh);
 474
 475         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 476         if (!ep)
 477                 return -EIO;
 478
 479         exfat_init_stream_entry(ep,
 480                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 481                 start_clu, size);
 482         exfat_update_bh(bh, IS_DIRSYNC(inode));
 483         brelse(bh);
 484
 485         return 0;
 486 }
 487
 488 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 489                 int entry)
 490 {
 491         struct super_block *sb = inode->i_sb;
 492         int ret = 0;
 493         int i, num_entries;
 494         sector_t sector;
 495         u16 chksum;
 496         struct exfat_dentry *ep, *fep;
 497         struct buffer_head *fbh, *bh;
 498
 499         fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
 500         if (!fep)
 501                 return -EIO;
 502
 503         num_entries = fep->dentry.file.num_ext + 1;
 504         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 505
 506         for (i = 1; i < num_entries; i++) {
 507                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
 508                 if (!ep) {
 509                         ret = -EIO;
 510                         goto release_fbh;
 511                 }
 512                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 513                                 CS_DEFAULT);
 514                 brelse(bh);
 515         }
 516
 517         fep->dentry.file.checksum = cpu_to_le16(chksum);
 518         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 519 release_fbh:
 520         brelse(fbh);
 521         return ret;
 522 }
 523
 524 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 525                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 526 {
 527         struct super_block *sb = inode->i_sb;
 528         int i;
 529         sector_t sector;
 530         unsigned short *uniname = p_uniname->name;
 531         struct exfat_dentry *ep;
 532         struct buffer_head *bh;
 533         int sync = IS_DIRSYNC(inode);
 534
 535         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 536         if (!ep)
 537                 return -EIO;
 538
 539         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 540         exfat_update_bh(bh, sync);
 541         brelse(bh);
 542
 543         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 544         if (!ep)
 545                 return -EIO;
 546
 547         ep->dentry.stream.name_len = p_uniname->name_len;
 548         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 549         exfat_update_bh(bh, sync);
 550         brelse(bh);
 551
 552         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
 553                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 554                 if (!ep)
 555                         return -EIO;
 556
 557                 exfat_init_name_entry(ep, uniname);
 558                 exfat_update_bh(bh, sync);
 559                 brelse(bh);
 560                 uniname += EXFAT_FILE_NAME_LEN;
 561         }
 562
 563         exfat_update_dir_chksum(inode, p_dir, entry);
 564         return 0;
 565 }
 566
 567 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 568                 int entry, int order, int num_entries)
 569 {
 570         struct super_block *sb = inode->i_sb;
 571         int i;
 572         sector_t sector;
 573         struct exfat_dentry *ep;
 574         struct buffer_head *bh;
 575
 576         for (i = order; i < num_entries; i++) {
 577                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 578                 if (!ep)
 579                         return -EIO;
 580
 581                 exfat_set_entry_type(ep, TYPE_DELETED);
 582                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 583                 brelse(bh);
 584         }
 585
 586         return 0;
 587 }
 588
 589 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 590 {
 591         int chksum_type = CS_DIR_ENTRY, i;
 592         unsigned short chksum = 0;
 593         struct exfat_dentry *ep;
 594
 595         for (i = 0; i < es->num_entries; i++) {
 596                 ep = exfat_get_dentry_cached(es, i);
 597                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 598                                              chksum_type);
 599                 chksum_type = CS_DEFAULT;
 600         }
 601         ep = exfat_get_dentry_cached(es, 0);
 602         ep->dentry.file.checksum = cpu_to_le16(chksum);
 603         es->modified = true;
 604 }
 605
 606 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 607 {
 608         int i, err = 0;
 609
 610         if (es->modified)
 611                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 612
 613         for (i = 0; i < es->num_bh; i++)
 614                 if (err)
 615                         bforget(es->bh[i]);
 616                 else
 617                         brelse(es->bh[i]);
 618         kfree(es);
 619         return err;
 620 }
 621
 622 static int exfat_walk_fat_chain(struct super_block *sb,
 623                 struct exfat_chain *p_dir, unsigned int byte_offset,
 624                 unsigned int *clu)
 625 {
 626         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 627         unsigned int clu_offset;
 628         unsigned int cur_clu;
 629
 630         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 631         cur_clu = p_dir->dir;
 632
 633         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 634                 cur_clu += clu_offset;
 635         } else {
 636                 while (clu_offset > 0) {
 637                         if (exfat_get_next_cluster(sb, &cur_clu))
 638                                 return -EIO;
 639                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 640                                 exfat_fs_error(sb,
 641                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 642                                         p_dir->dir,
 643                                         EXFAT_B_TO_DEN(byte_offset));
 644                                 return -EIO;
 645                         }
 646                         clu_offset--;
 647                 }
 648         }
 649
 650         *clu = cur_clu;
 651         return 0;
 652 }
 653
 654 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 655                 int entry, sector_t *sector, int *offset)
 656 {
 657         int ret;
 658         unsigned int off, clu = 0;
 659         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 660
 661         off = EXFAT_DEN_TO_B(entry);
 662
 663         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 664         if (ret)
 665                 return ret;
 666
 667         /* byte offset in cluster */
 668         off = EXFAT_CLU_OFFSET(off, sbi);
 669
 670         /* byte offset in sector    */
 671         *offset = EXFAT_BLK_OFFSET(off, sb);
 672
 673         /* sector offset in cluster */
 674         *sector = EXFAT_B_TO_BLK(off, sb);
 675         *sector += exfat_cluster_to_sector(sbi, clu);
 676         return 0;
 677 }
 678
 679 #define EXFAT_MAX_RA_SIZE     (128*1024)
 680 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 681 {
 682         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 683         struct buffer_head *bh;
 684         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 685         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 686         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 687         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 688
 689         /* Read-ahead is not required */
 690         if (sbi->sect_per_clus == 1)
 691                 return 0;
 692
 693         if (sec < sbi->data_start_sector) {
 694                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 695                           (unsigned long long)sec, sbi->data_start_sector);
 696                 return -EIO;
 697         }
 698
 699         /* Not sector aligned with ra_count, resize ra_count to page size */
 700         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 701                 ra_count = page_ra_count;
 702
 703         bh = sb_find_get_block(sb, sec);
 704         if (!bh || !buffer_uptodate(bh)) {
 705                 unsigned int i;
 706
 707                 for (i = 0; i < ra_count; i++)
 708                         sb_breadahead(sb, (sector_t)(sec + i));
 709         }
 710         brelse(bh);
 711         return 0;
 712 }
 713
 714 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 715                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 716                 sector_t *sector)
 717 {
 718         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 719         int off;
 720         sector_t sec;
 721
 722         if (p_dir->dir == DIR_DELETED) {
 723                 exfat_err(sb, "abnormal access to deleted dentry");
 724                 return NULL;
 725         }
 726
 727         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 728                 return NULL;
 729
 730         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 731                         !(entry & (dentries_per_page - 1)))
 732                 exfat_dir_readahead(sb, sec);
 733
 734         *bh = sb_bread(sb, sec);
 735         if (!*bh)
 736                 return NULL;
 737
 738         if (sector)
 739                 *sector = sec;
 740         return (struct exfat_dentry *)((*bh)->b_data + off);
 741 }
 742
 743 enum exfat_validate_dentry_mode {
 744         ES_MODE_STARTED,
 745         ES_MODE_GET_FILE_ENTRY,
 746         ES_MODE_GET_STRM_ENTRY,
 747         ES_MODE_GET_NAME_ENTRY,
 748         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 749 };
 750
 751 static bool exfat_validate_entry(unsigned int type,
 752                 enum exfat_validate_dentry_mode *mode)
 753 {
 754         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 755                 return false;
 756
 757         switch (*mode) {
 758         case ES_MODE_STARTED:
 759                 if  (type != TYPE_FILE && type != TYPE_DIR)
 760                         return false;
 761                 *mode = ES_MODE_GET_FILE_ENTRY;
 762                 return true;
 763         case ES_MODE_GET_FILE_ENTRY:
 764                 if (type != TYPE_STREAM)
 765                         return false;
 766                 *mode = ES_MODE_GET_STRM_ENTRY;
 767                 return true;
 768         case ES_MODE_GET_STRM_ENTRY:
 769                 if (type != TYPE_EXTEND)
 770                         return false;
 771                 *mode = ES_MODE_GET_NAME_ENTRY;
 772                 return true;
 773         case ES_MODE_GET_NAME_ENTRY:
 774                 if (type == TYPE_STREAM)
 775                         return false;
 776                 if (type != TYPE_EXTEND) {
 777                         if (!(type & TYPE_CRITICAL_SEC))
 778                                 return false;
 779                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 780                 }
 781                 return true;
 782         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 783                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 784                         return false;
 785                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 786                         return false;
 787                 return true;
 788         default:
 789                 WARN_ON_ONCE(1);
 790                 return false;
 791         }
 792 }
 793
 794 struct exfat_dentry *exfat_get_dentry_cached(
 795         struct exfat_entry_set_cache *es, int num)
 796 {
 797         int off = es->start_off + num * DENTRY_SIZE;
 798         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 799         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 800
 801         return (struct exfat_dentry *)p;
 802 }
 803
 804 /*
 805  * Returns a set of dentries for a file or dir.
 806  *
 807  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 808  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 809  * changes made in this entry set to the real device.
 810  *
 811  * in:
 812  *   sb+p_dir+entry: indicates a file/dir
 813  *   type:  specifies how many dentries should be included.
 814  * return:
 815  *   pointer of entry set on success,
 816  *   NULL on failure.
 817  */
 818 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 819                 struct exfat_chain *p_dir, int entry, unsigned int type)
 820 {
 821         int ret, i, num_bh;
 822         unsigned int off, byte_offset, clu = 0;
 823         sector_t sec;
 824         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 825         struct exfat_entry_set_cache *es;
 826         struct exfat_dentry *ep;
 827         int num_entries;
 828         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 829         struct buffer_head *bh;
 830
 831         if (p_dir->dir == DIR_DELETED) {
 832                 exfat_err(sb, "access to deleted dentry");
 833                 return NULL;
 834         }
 835
 836         byte_offset = EXFAT_DEN_TO_B(entry);
 837         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
 838         if (ret)
 839                 return NULL;
 840
 841         es = kzalloc(sizeof(*es), GFP_KERNEL);
 842         if (!es)
 843                 return NULL;
 844         es->sb = sb;
 845         es->modified = false;
 846
 847         /* byte offset in cluster */
 848         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 849
 850         /* byte offset in sector */
 851         off = EXFAT_BLK_OFFSET(byte_offset, sb);
 852         es->start_off = off;
 853
 854         /* sector offset in cluster */
 855         sec = EXFAT_B_TO_BLK(byte_offset, sb);
 856         sec += exfat_cluster_to_sector(sbi, clu);
 857
 858         bh = sb_bread(sb, sec);
 859         if (!bh)
 860                 goto free_es;
 861         es->bh[es->num_bh++] = bh;
 862
 863         ep = exfat_get_dentry_cached(es, 0);
 864         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 865                 goto free_es;
 866
 867         num_entries = type == ES_ALL_ENTRIES ?
 868                 ep->dentry.file.num_ext + 1 : type;
 869         es->num_entries = num_entries;
 870
 871         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 872         for (i = 1; i < num_bh; i++) {
 873                 /* get the next sector */
 874                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 875                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 876                                 clu++;
 877                         else if (exfat_get_next_cluster(sb, &clu))
 878                                 goto free_es;
 879                         sec = exfat_cluster_to_sector(sbi, clu);
 880                 } else {
 881                         sec++;
 882                 }
 883
 884                 bh = sb_bread(sb, sec);
 885                 if (!bh)
 886                         goto free_es;
 887                 es->bh[es->num_bh++] = bh;
 888         }
 889
 890         /* validiate cached dentries */
 891         for (i = 1; i < num_entries; i++) {
 892                 ep = exfat_get_dentry_cached(es, i);
 893                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 894                         goto free_es;
 895         }
 896         return es;
 897
 898 free_es:
 899         exfat_free_dentry_set(es, false);
 900         return NULL;
 901 }
 902
 903 enum {
 904         DIRENT_STEP_FILE,
 905         DIRENT_STEP_STRM,
 906         DIRENT_STEP_NAME,
 907         DIRENT_STEP_SECD,
 908 };
 909
 910 /*
 911  * return values:
 912  *   >= 0       : return dir entiry position with the name in dir
 913  *   -ENOENT    : entry with the name does not exist
 914  *   -EIO       : I/O error
 915  */
 916 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 917                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 918                 int num_entries, unsigned int type)
 919 {
 920         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 921         int order, step, name_len = 0;
 922         int dentries_per_clu, num_empty = 0;
 923         unsigned int entry_type;
 924         unsigned short *uniname = NULL;
 925         struct exfat_chain clu;
 926         struct exfat_hint *hint_stat = &ei->hint_stat;
 927         struct exfat_hint_femp candi_empty;
 928         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 929
 930         dentries_per_clu = sbi->dentries_per_clu;
 931
 932         exfat_chain_dup(&clu, p_dir);
 933
 934         if (hint_stat->eidx) {
 935                 clu.dir = hint_stat->clu;
 936                 dentry = hint_stat->eidx;
 937                 end_eidx = dentry;
 938         }
 939
 940         candi_empty.eidx = EXFAT_HINT_NONE;
 941 rewind:
 942         order = 0;
 943         step = DIRENT_STEP_FILE;
 944         while (clu.dir != EXFAT_EOF_CLUSTER) {
 945                 i = dentry & (dentries_per_clu - 1);
 946                 for (; i < dentries_per_clu; i++, dentry++) {
 947                         struct exfat_dentry *ep;
 948                         struct buffer_head *bh;
 949
 950                         if (rewind && dentry == end_eidx)
 951                                 goto not_found;
 952
 953                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
 954                         if (!ep)
 955                                 return -EIO;
 956
 957                         entry_type = exfat_get_entry_type(ep);
 958
 959                         if (entry_type == TYPE_UNUSED ||
 960                             entry_type == TYPE_DELETED) {
 961                                 step = DIRENT_STEP_FILE;
 962
 963                                 num_empty++;
 964                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 965                                                 num_empty == 1) {
 966                                         exfat_chain_set(&candi_empty.cur,
 967                                                 clu.dir, clu.size, clu.flags);
 968                                 }
 969
 970                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 971                                                 num_empty >= num_entries) {
 972                                         candi_empty.eidx =
 973                                                 dentry - (num_empty - 1);
 974                                         WARN_ON(candi_empty.eidx < 0);
 975                                         candi_empty.count = num_empty;
 976
 977                                         if (ei->hint_femp.eidx ==
 978                                                         EXFAT_HINT_NONE ||
 979                                                 candi_empty.eidx <=
 980                                                          ei->hint_femp.eidx)
 981                                                 ei->hint_femp = candi_empty;
 982                                 }
 983
 984                                 brelse(bh);
 985                                 if (entry_type == TYPE_UNUSED)
 986                                         goto not_found;
 987                                 continue;
 988                         }
 989
 990                         num_empty = 0;
 991                         candi_empty.eidx = EXFAT_HINT_NONE;
 992
 993                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
 994                                 step = DIRENT_STEP_FILE;
 995                                 if (type == TYPE_ALL || type == entry_type) {
 996                                         num_ext = ep->dentry.file.num_ext;
 997                                         step = DIRENT_STEP_STRM;
 998                                 }
 999                                 brelse(bh);
1000                                 continue;
1001                         }
1002
1003                         if (entry_type == TYPE_STREAM) {
1004                                 u16 name_hash;
1005
1006                                 if (step != DIRENT_STEP_STRM) {
1007                                         step = DIRENT_STEP_FILE;
1008                                         brelse(bh);
1009                                         continue;
1010                                 }
1011                                 step = DIRENT_STEP_FILE;
1012                                 name_hash = le16_to_cpu(
1013                                                 ep->dentry.stream.name_hash);
1014                                 if (p_uniname->name_hash == name_hash &&
1015                                     p_uniname->name_len ==
1016                                                 ep->dentry.stream.name_len) {
1017                                         step = DIRENT_STEP_NAME;
1018                                         order = 1;
1019                                         name_len = 0;
1020                                 }
1021                                 brelse(bh);
1022                                 continue;
1023                         }
1024
1025                         brelse(bh);
1026                         if (entry_type == TYPE_EXTEND) {
1027                                 unsigned short entry_uniname[16], unichar;
1028
1029                                 if (step != DIRENT_STEP_NAME) {
1030                                         step = DIRENT_STEP_FILE;
1031                                         continue;
1032                                 }
1033
1034                                 if (++order == 2)
1035                                         uniname = p_uniname->name;
1036                                 else
1037                                         uniname += EXFAT_FILE_NAME_LEN;
1038
1039                                 len = exfat_extract_uni_name(ep, entry_uniname);
1040                                 name_len += len;
1041
1042                                 unichar = *(uniname+len);
1043                                 *(uniname+len) = 0x0;
1044
1045                                 if (exfat_uniname_ncmp(sb, uniname,
1046                                         entry_uniname, len)) {
1047                                         step = DIRENT_STEP_FILE;
1048                                 } else if (p_uniname->name_len == name_len) {
1049                                         if (order == num_ext)
1050                                                 goto found;
1051                                         step = DIRENT_STEP_SECD;
1052                                 }
1053
1054                                 *(uniname+len) = unichar;
1055                                 continue;
1056                         }
1057
1058                         if (entry_type &
1059                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1060                                 if (step == DIRENT_STEP_SECD) {
1061                                         if (++order == num_ext)
1062                                                 goto found;
1063                                         continue;
1064                                 }
1065                         }
1066                         step = DIRENT_STEP_FILE;
1067                 }
1068
1069                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1070                         if (--clu.size > 0)
1071                                 clu.dir++;
1072                         else
1073                                 clu.dir = EXFAT_EOF_CLUSTER;
1074                 } else {
1075                         if (exfat_get_next_cluster(sb, &clu.dir))
1076                                 return -EIO;
1077                 }
1078         }
1079
1080 not_found:
1081         /*
1082          * We started at not 0 index,so we should try to find target
1083          * from 0 index to the index we started at.
1084          */
1085         if (!rewind && end_eidx) {
1086                 rewind = 1;
1087                 dentry = 0;
1088                 clu.dir = p_dir->dir;
1089                 /* reset empty hint */
1090                 num_empty = 0;
1091                 candi_empty.eidx = EXFAT_HINT_NONE;
1092                 goto rewind;
1093         }
1094
1095         /* initialized hint_stat */
1096         hint_stat->clu = p_dir->dir;
1097         hint_stat->eidx = 0;
1098         return -ENOENT;
1099
1100 found:
1101         /* next dentry we'll find is out of this cluster */
1102         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1103                 int ret = 0;
1104
1105                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1106                         if (--clu.size > 0)
1107                                 clu.dir++;
1108                         else
1109                                 clu.dir = EXFAT_EOF_CLUSTER;
1110                 } else {
1111                         ret = exfat_get_next_cluster(sb, &clu.dir);
1112                 }
1113
1114                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1115                         /* just initialized hint_stat */
1116                         hint_stat->clu = p_dir->dir;
1117                         hint_stat->eidx = 0;
1118                         return (dentry - num_ext);
1119                 }
1120         }
1121
1122         hint_stat->clu = clu.dir;
1123         hint_stat->eidx = dentry + 1;
1124         return dentry - num_ext;
1125 }
1126
1127 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1128                 int entry, struct exfat_dentry *ep)
1129 {
1130         int i, count = 0;
1131         unsigned int type;
1132         struct exfat_dentry *ext_ep;
1133         struct buffer_head *bh;
1134
1135         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1136                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
1137                 if (!ext_ep)
1138                         return -EIO;
1139
1140                 type = exfat_get_entry_type(ext_ep);
1141                 brelse(bh);
1142                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1143                         count++;
1144                 else
1145                         break;
1146         }
1147         return count;
1148 }
1149
1150 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1151 {
1152         int i, count = 0;
1153         int dentries_per_clu;
1154         unsigned int entry_type;
1155         struct exfat_chain clu;
1156         struct exfat_dentry *ep;
1157         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1158         struct buffer_head *bh;
1159
1160         dentries_per_clu = sbi->dentries_per_clu;
1161
1162         exfat_chain_dup(&clu, p_dir);
1163
1164         while (clu.dir != EXFAT_EOF_CLUSTER) {
1165                 for (i = 0; i < dentries_per_clu; i++) {
1166                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
1167                         if (!ep)
1168                                 return -EIO;
1169                         entry_type = exfat_get_entry_type(ep);
1170                         brelse(bh);
1171
1172                         if (entry_type == TYPE_UNUSED)
1173                                 return count;
1174                         if (entry_type != TYPE_DIR)
1175                                 continue;
1176                         count++;
1177                 }
1178
1179                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1180                         if (--clu.size > 0)
1181                                 clu.dir++;
1182                         else
1183                                 clu.dir = EXFAT_EOF_CLUSTER;
1184                 } else {
1185                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1186                                 return -EIO;
1187                 }
1188         }
1189
1190         return count;
1191 }