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/compat.h>
   8 #include <linux/bio.h>
   9 #include <linux/buffer_head.h>
  10
  11 #include "exfat_raw.h"
  12 #include "exfat_fs.h"
  13
  14 static int exfat_extract_uni_name(struct exfat_dentry *ep,
  15                 unsigned short *uniname)
  16 {
  17         int i, len = 0;
  18
  19         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
  20                 *uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
  21                 if (*uniname == 0x0)
  22                         return len;
  23                 uniname++;
  24                 len++;
  25         }
  26
  27         *uniname = 0x0;
  28         return len;
  29
  30 }
  31
  32 static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
  33                 struct exfat_chain *p_dir, int entry, unsigned short *uniname)
  34 {
  35         int i;
  36         struct exfat_entry_set_cache *es;
  37
  38         es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
  39         if (!es)
  40                 return;
  41
  42         /*
  43          * First entry  : file entry
  44          * Second entry : stream-extension entry
  45          * Third entry  : first file-name entry
  46          * So, the index of first file-name dentry should start from 2.
  47          */
  48         for (i = 2; i < es->num_entries; i++) {
  49                 struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
  50
  51                 /* end of name entry */
  52                 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
  53                         break;
  54
  55                 exfat_extract_uni_name(ep, uniname);
  56                 uniname += EXFAT_FILE_NAME_LEN;
  57         }
  58
  59         exfat_free_dentry_set(es, false);
  60 }
  61
  62 /* read a directory entry from the opened directory */
  63 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  64 {
  65         int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
  66         unsigned int type, clu_offset;
  67         sector_t sector;
  68         struct exfat_chain dir, clu;
  69         struct exfat_uni_name uni_name;
  70         struct exfat_dentry *ep;
  71         struct super_block *sb = inode->i_sb;
  72         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  73         struct exfat_inode_info *ei = EXFAT_I(inode);
  74         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  75         struct buffer_head *bh;
  76
  77         /* check if the given file ID is opened */
  78         if (ei->type != TYPE_DIR)
  79                 return -EPERM;
  80
  81         if (ei->entry == -1)
  82                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  83         else
  84                 exfat_chain_set(&dir, ei->start_clu,
  85                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  86
  87         dentries_per_clu = sbi->dentries_per_clu;
  88         dentries_per_clu_bits = ilog2(dentries_per_clu);
  89
  90         clu_offset = dentry >> dentries_per_clu_bits;
  91         exfat_chain_dup(&clu, &dir);
  92
  93         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  94                 clu.dir += clu_offset;
  95                 clu.size -= clu_offset;
  96         } else {
  97                 /* hint_information */
  98                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
  99                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 100                         clu_offset -= ei->hint_bmap.off;
 101                         clu.dir = ei->hint_bmap.clu;
 102                 }
 103
 104                 while (clu_offset > 0) {
 105                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 106                                 return -EIO;
 107
 108                         clu_offset--;
 109                 }
 110         }
 111
 112         while (clu.dir != EXFAT_EOF_CLUSTER) {
 113                 i = dentry & (dentries_per_clu - 1);
 114
 115                 for ( ; i < dentries_per_clu; i++, dentry++) {
 116                         ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
 117                         if (!ep)
 118                                 return -EIO;
 119
 120                         type = exfat_get_entry_type(ep);
 121                         if (type == TYPE_UNUSED) {
 122                                 brelse(bh);
 123                                 break;
 124                         }
 125
 126                         if (type != TYPE_FILE && type != TYPE_DIR) {
 127                                 brelse(bh);
 128                                 continue;
 129                         }
 130
 131                         num_ext = ep->dentry.file.num_ext;
 132                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 133                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 134                                         ep->dentry.file.create_tz,
 135                                         ep->dentry.file.create_time,
 136                                         ep->dentry.file.create_date,
 137                                         ep->dentry.file.create_time_cs);
 138                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 139                                         ep->dentry.file.modify_tz,
 140                                         ep->dentry.file.modify_time,
 141                                         ep->dentry.file.modify_date,
 142                                         ep->dentry.file.modify_time_cs);
 143                         exfat_get_entry_time(sbi, &dir_entry->atime,
 144                                         ep->dentry.file.access_tz,
 145                                         ep->dentry.file.access_time,
 146                                         ep->dentry.file.access_date,
 147                                         0);
 148
 149                         *uni_name.name = 0x0;
 150                         exfat_get_uniname_from_ext_entry(sb, &clu, i,
 151                                 uni_name.name);
 152                         exfat_utf16_to_nls(sb, &uni_name,
 153                                 dir_entry->namebuf.lfn,
 154                                 dir_entry->namebuf.lfnbuf_len);
 155                         brelse(bh);
 156
 157                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
 158                         if (!ep)
 159                                 return -EIO;
 160                         dir_entry->size =
 161                                 le64_to_cpu(ep->dentry.stream.valid_size);
 162                         dir_entry->entry = dentry;
 163                         brelse(bh);
 164
 165                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
 166                         ei->hint_bmap.clu = clu.dir;
 167
 168                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 169                         return 0;
 170                 }
 171
 172                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 173                         if (--clu.size > 0)
 174                                 clu.dir++;
 175                         else
 176                                 clu.dir = EXFAT_EOF_CLUSTER;
 177                 } else {
 178                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 179                                 return -EIO;
 180                 }
 181         }
 182
 183         dir_entry->namebuf.lfn[0] = '\0';
 184         *cpos = EXFAT_DEN_TO_B(dentry);
 185         return 0;
 186 }
 187
 188 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 189 {
 190         nb->lfn = NULL;
 191         nb->lfnbuf_len = 0;
 192 }
 193
 194 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 195 {
 196         nb->lfn = __getname();
 197         if (!nb->lfn)
 198                 return -ENOMEM;
 199         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 200         return 0;
 201 }
 202
 203 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 204 {
 205         if (!nb->lfn)
 206                 return;
 207
 208         __putname(nb->lfn);
 209         exfat_init_namebuf(nb);
 210 }
 211
 212 /* skip iterating emit_dots when dir is empty */
 213 #define ITER_POS_FILLED_DOTS    (2)
 214 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
 215 {
 216         struct inode *inode = filp->f_path.dentry->d_inode;
 217         struct super_block *sb = inode->i_sb;
 218         struct inode *tmp;
 219         struct exfat_dir_entry de;
 220         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 221         struct exfat_inode_info *ei = EXFAT_I(inode);
 222         unsigned long inum;
 223         loff_t cpos, i_pos;
 224         int err = 0, fake_offset = 0;
 225
 226         exfat_init_namebuf(nb);
 227         mutex_lock(&EXFAT_SB(sb)->s_lock);
 228
 229         cpos = ctx->pos;
 230         if (!dir_emit_dots(filp, ctx))
 231                 goto unlock;
 232
 233         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 234                 cpos = 0;
 235                 fake_offset = 1;
 236         }
 237
 238         if (cpos & (DENTRY_SIZE - 1)) {
 239                 err = -ENOENT;
 240                 goto unlock;
 241         }
 242
 243         /* name buffer should be allocated before use */
 244         err = exfat_alloc_namebuf(nb);
 245         if (err)
 246                 goto unlock;
 247 get_new:
 248         if (cpos >= i_size_read(inode))
 249                 goto end_of_dir;
 250
 251         err = exfat_readdir(inode, &cpos, &de);
 252         if (err) {
 253                 /*
 254                  * At least we tried to read a sector.  Move cpos to next sector
 255                  * position (should be aligned).
 256                  */
 257                 if (err == -EIO) {
 258                         cpos += 1 << (sb->s_blocksize_bits);
 259                         cpos &= ~(sb->s_blocksize - 1);
 260                 }
 261
 262                 err = -EIO;
 263                 goto end_of_dir;
 264         }
 265
 266         if (!nb->lfn[0])
 267                 goto end_of_dir;
 268
 269         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 270         tmp = exfat_iget(sb, i_pos);
 271         if (tmp) {
 272                 inum = tmp->i_ino;
 273                 iput(tmp);
 274         } else {
 275                 inum = iunique(sb, EXFAT_ROOT_INO);
 276         }
 277
 278         /*
 279          * Before calling dir_emit(), sb_lock should be released.
 280          * Because page fault can occur in dir_emit() when the size
 281          * of buffer given from user is larger than one page size.
 282          */
 283         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 284         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 285                         (de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
 286                 goto out_unlocked;
 287         mutex_lock(&EXFAT_SB(sb)->s_lock);
 288         ctx->pos = cpos;
 289         goto get_new;
 290
 291 end_of_dir:
 292         if (!cpos && fake_offset)
 293                 cpos = ITER_POS_FILLED_DOTS;
 294         ctx->pos = cpos;
 295 unlock:
 296         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 297 out_unlocked:
 298         /*
 299          * To improve performance, free namebuf after unlock sb_lock.
 300          * If namebuf is not allocated, this function do nothing
 301          */
 302         exfat_free_namebuf(nb);
 303         return err;
 304 }
 305
 306 const struct file_operations exfat_dir_operations = {
 307         .llseek         = generic_file_llseek,
 308         .read           = generic_read_dir,
 309         .iterate        = exfat_iterate,
 310         .unlocked_ioctl = exfat_ioctl,
 311 #ifdef CONFIG_COMPAT
 312         .compat_ioctl = exfat_compat_ioctl,
 313 #endif
 314         .fsync          = exfat_file_fsync,
 315 };
 316
 317 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 318 {
 319         int ret;
 320
 321         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 322
 323         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 324         if (ret)
 325                 return ret;
 326
 327         return exfat_zeroed_cluster(inode, clu->dir);
 328 }
 329
 330 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 331 {
 332         int len;
 333
 334         len = p_uniname->name_len;
 335         if (len == 0)
 336                 return -EINVAL;
 337
 338         /* 1 file entry + 1 stream entry + name entries */
 339         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 340 }
 341
 342 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 343 {
 344         if (ep->type == EXFAT_UNUSED)
 345                 return TYPE_UNUSED;
 346         if (IS_EXFAT_DELETED(ep->type))
 347                 return TYPE_DELETED;
 348         if (ep->type == EXFAT_INVAL)
 349                 return TYPE_INVALID;
 350         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 351                 if (ep->type == EXFAT_BITMAP)
 352                         return TYPE_BITMAP;
 353                 if (ep->type == EXFAT_UPCASE)
 354                         return TYPE_UPCASE;
 355                 if (ep->type == EXFAT_VOLUME)
 356                         return TYPE_VOLUME;
 357                 if (ep->type == EXFAT_FILE) {
 358                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 359                                 return TYPE_DIR;
 360                         return TYPE_FILE;
 361                 }
 362                 return TYPE_CRITICAL_PRI;
 363         }
 364         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 365                 if (ep->type == EXFAT_GUID)
 366                         return TYPE_GUID;
 367                 if (ep->type == EXFAT_PADDING)
 368                         return TYPE_PADDING;
 369                 if (ep->type == EXFAT_ACLTAB)
 370                         return TYPE_ACLTAB;
 371                 return TYPE_BENIGN_PRI;
 372         }
 373         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 374                 if (ep->type == EXFAT_STREAM)
 375                         return TYPE_STREAM;
 376                 if (ep->type == EXFAT_NAME)
 377                         return TYPE_EXTEND;
 378                 if (ep->type == EXFAT_ACL)
 379                         return TYPE_ACL;
 380                 return TYPE_CRITICAL_SEC;
 381         }
 382         return TYPE_BENIGN_SEC;
 383 }
 384
 385 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 386 {
 387         if (type == TYPE_UNUSED) {
 388                 ep->type = EXFAT_UNUSED;
 389         } else if (type == TYPE_DELETED) {
 390                 ep->type &= EXFAT_DELETE;
 391         } else if (type == TYPE_STREAM) {
 392                 ep->type = EXFAT_STREAM;
 393         } else if (type == TYPE_EXTEND) {
 394                 ep->type = EXFAT_NAME;
 395         } else if (type == TYPE_BITMAP) {
 396                 ep->type = EXFAT_BITMAP;
 397         } else if (type == TYPE_UPCASE) {
 398                 ep->type = EXFAT_UPCASE;
 399         } else if (type == TYPE_VOLUME) {
 400                 ep->type = EXFAT_VOLUME;
 401         } else if (type == TYPE_DIR) {
 402                 ep->type = EXFAT_FILE;
 403                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 404         } else if (type == TYPE_FILE) {
 405                 ep->type = EXFAT_FILE;
 406                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 407         }
 408 }
 409
 410 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 411                 unsigned char flags, unsigned int start_clu,
 412                 unsigned long long size)
 413 {
 414         exfat_set_entry_type(ep, TYPE_STREAM);
 415         ep->dentry.stream.flags = flags;
 416         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 417         ep->dentry.stream.valid_size = cpu_to_le64(size);
 418         ep->dentry.stream.size = cpu_to_le64(size);
 419 }
 420
 421 static void exfat_init_name_entry(struct exfat_dentry *ep,
 422                 unsigned short *uniname)
 423 {
 424         int i;
 425
 426         exfat_set_entry_type(ep, TYPE_EXTEND);
 427         ep->dentry.name.flags = 0x0;
 428
 429         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 430                 if (*uniname != 0x0) {
 431                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 432                         uniname++;
 433                 } else {
 434                         ep->dentry.name.unicode_0_14[i] = 0x0;
 435                 }
 436         }
 437 }
 438
 439 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 440                 int entry, unsigned int type, unsigned int start_clu,
 441                 unsigned long long size)
 442 {
 443         struct super_block *sb = inode->i_sb;
 444         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 445         struct timespec64 ts = current_time(inode);
 446         sector_t sector;
 447         struct exfat_dentry *ep;
 448         struct buffer_head *bh;
 449
 450         /*
 451          * We cannot use exfat_get_dentry_set here because file ep is not
 452          * initialized yet.
 453          */
 454         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 455         if (!ep)
 456                 return -EIO;
 457
 458         exfat_set_entry_type(ep, type);
 459         exfat_set_entry_time(sbi, &ts,
 460                         &ep->dentry.file.create_tz,
 461                         &ep->dentry.file.create_time,
 462                         &ep->dentry.file.create_date,
 463                         &ep->dentry.file.create_time_cs);
 464         exfat_set_entry_time(sbi, &ts,
 465                         &ep->dentry.file.modify_tz,
 466                         &ep->dentry.file.modify_time,
 467                         &ep->dentry.file.modify_date,
 468                         &ep->dentry.file.modify_time_cs);
 469         exfat_set_entry_time(sbi, &ts,
 470                         &ep->dentry.file.access_tz,
 471                         &ep->dentry.file.access_time,
 472                         &ep->dentry.file.access_date,
 473                         NULL);
 474
 475         exfat_update_bh(bh, IS_DIRSYNC(inode));
 476         brelse(bh);
 477
 478         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 479         if (!ep)
 480                 return -EIO;
 481
 482         exfat_init_stream_entry(ep,
 483                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 484                 start_clu, size);
 485         exfat_update_bh(bh, IS_DIRSYNC(inode));
 486         brelse(bh);
 487
 488         return 0;
 489 }
 490
 491 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 492                 int entry)
 493 {
 494         struct super_block *sb = inode->i_sb;
 495         int ret = 0;
 496         int i, num_entries;
 497         sector_t sector;
 498         u16 chksum;
 499         struct exfat_dentry *ep, *fep;
 500         struct buffer_head *fbh, *bh;
 501
 502         fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
 503         if (!fep)
 504                 return -EIO;
 505
 506         num_entries = fep->dentry.file.num_ext + 1;
 507         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 508
 509         for (i = 1; i < num_entries; i++) {
 510                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
 511                 if (!ep) {
 512                         ret = -EIO;
 513                         goto release_fbh;
 514                 }
 515                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 516                                 CS_DEFAULT);
 517                 brelse(bh);
 518         }
 519
 520         fep->dentry.file.checksum = cpu_to_le16(chksum);
 521         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 522 release_fbh:
 523         brelse(fbh);
 524         return ret;
 525 }
 526
 527 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 528                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 529 {
 530         struct super_block *sb = inode->i_sb;
 531         int i;
 532         sector_t sector;
 533         unsigned short *uniname = p_uniname->name;
 534         struct exfat_dentry *ep;
 535         struct buffer_head *bh;
 536         int sync = IS_DIRSYNC(inode);
 537
 538         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 539         if (!ep)
 540                 return -EIO;
 541
 542         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 543         exfat_update_bh(bh, sync);
 544         brelse(bh);
 545
 546         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 547         if (!ep)
 548                 return -EIO;
 549
 550         ep->dentry.stream.name_len = p_uniname->name_len;
 551         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 552         exfat_update_bh(bh, sync);
 553         brelse(bh);
 554
 555         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
 556                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 557                 if (!ep)
 558                         return -EIO;
 559
 560                 exfat_init_name_entry(ep, uniname);
 561                 exfat_update_bh(bh, sync);
 562                 brelse(bh);
 563                 uniname += EXFAT_FILE_NAME_LEN;
 564         }
 565
 566         exfat_update_dir_chksum(inode, p_dir, entry);
 567         return 0;
 568 }
 569
 570 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 571                 int entry, int order, int num_entries)
 572 {
 573         struct super_block *sb = inode->i_sb;
 574         int i;
 575         sector_t sector;
 576         struct exfat_dentry *ep;
 577         struct buffer_head *bh;
 578
 579         for (i = order; i < num_entries; i++) {
 580                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 581                 if (!ep)
 582                         return -EIO;
 583
 584                 exfat_set_entry_type(ep, TYPE_DELETED);
 585                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 586                 brelse(bh);
 587         }
 588
 589         return 0;
 590 }
 591
 592 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 593 {
 594         int chksum_type = CS_DIR_ENTRY, i;
 595         unsigned short chksum = 0;
 596         struct exfat_dentry *ep;
 597
 598         for (i = 0; i < es->num_entries; i++) {
 599                 ep = exfat_get_dentry_cached(es, i);
 600                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 601                                              chksum_type);
 602                 chksum_type = CS_DEFAULT;
 603         }
 604         ep = exfat_get_dentry_cached(es, 0);
 605         ep->dentry.file.checksum = cpu_to_le16(chksum);
 606         es->modified = true;
 607 }
 608
 609 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 610 {
 611         int i, err = 0;
 612
 613         if (es->modified)
 614                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 615
 616         for (i = 0; i < es->num_bh; i++)
 617                 if (err)
 618                         bforget(es->bh[i]);
 619                 else
 620                         brelse(es->bh[i]);
 621         kfree(es);
 622         return err;
 623 }
 624
 625 static int exfat_walk_fat_chain(struct super_block *sb,
 626                 struct exfat_chain *p_dir, unsigned int byte_offset,
 627                 unsigned int *clu)
 628 {
 629         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 630         unsigned int clu_offset;
 631         unsigned int cur_clu;
 632
 633         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 634         cur_clu = p_dir->dir;
 635
 636         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 637                 cur_clu += clu_offset;
 638         } else {
 639                 while (clu_offset > 0) {
 640                         if (exfat_get_next_cluster(sb, &cur_clu))
 641                                 return -EIO;
 642                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 643                                 exfat_fs_error(sb,
 644                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 645                                         p_dir->dir,
 646                                         EXFAT_B_TO_DEN(byte_offset));
 647                                 return -EIO;
 648                         }
 649                         clu_offset--;
 650                 }
 651         }
 652
 653         *clu = cur_clu;
 654         return 0;
 655 }
 656
 657 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 658                 int entry, sector_t *sector, int *offset)
 659 {
 660         int ret;
 661         unsigned int off, clu = 0;
 662         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 663
 664         off = EXFAT_DEN_TO_B(entry);
 665
 666         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 667         if (ret)
 668                 return ret;
 669
 670         /* byte offset in cluster */
 671         off = EXFAT_CLU_OFFSET(off, sbi);
 672
 673         /* byte offset in sector    */
 674         *offset = EXFAT_BLK_OFFSET(off, sb);
 675
 676         /* sector offset in cluster */
 677         *sector = EXFAT_B_TO_BLK(off, sb);
 678         *sector += exfat_cluster_to_sector(sbi, clu);
 679         return 0;
 680 }
 681
 682 #define EXFAT_MAX_RA_SIZE     (128*1024)
 683 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 684 {
 685         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 686         struct buffer_head *bh;
 687         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 688         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 689         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 690         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 691
 692         /* Read-ahead is not required */
 693         if (sbi->sect_per_clus == 1)
 694                 return 0;
 695
 696         if (sec < sbi->data_start_sector) {
 697                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 698                           (unsigned long long)sec, sbi->data_start_sector);
 699                 return -EIO;
 700         }
 701
 702         /* Not sector aligned with ra_count, resize ra_count to page size */
 703         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 704                 ra_count = page_ra_count;
 705
 706         bh = sb_find_get_block(sb, sec);
 707         if (!bh || !buffer_uptodate(bh)) {
 708                 unsigned int i;
 709
 710                 for (i = 0; i < ra_count; i++)
 711                         sb_breadahead(sb, (sector_t)(sec + i));
 712         }
 713         brelse(bh);
 714         return 0;
 715 }
 716
 717 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 718                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 719                 sector_t *sector)
 720 {
 721         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 722         int off;
 723         sector_t sec;
 724
 725         if (p_dir->dir == DIR_DELETED) {
 726                 exfat_err(sb, "abnormal access to deleted dentry");
 727                 return NULL;
 728         }
 729
 730         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 731                 return NULL;
 732
 733         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 734                         !(entry & (dentries_per_page - 1)))
 735                 exfat_dir_readahead(sb, sec);
 736
 737         *bh = sb_bread(sb, sec);
 738         if (!*bh)
 739                 return NULL;
 740
 741         if (sector)
 742                 *sector = sec;
 743         return (struct exfat_dentry *)((*bh)->b_data + off);
 744 }
 745
 746 enum exfat_validate_dentry_mode {
 747         ES_MODE_STARTED,
 748         ES_MODE_GET_FILE_ENTRY,
 749         ES_MODE_GET_STRM_ENTRY,
 750         ES_MODE_GET_NAME_ENTRY,
 751         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 752 };
 753
 754 static bool exfat_validate_entry(unsigned int type,
 755                 enum exfat_validate_dentry_mode *mode)
 756 {
 757         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 758                 return false;
 759
 760         switch (*mode) {
 761         case ES_MODE_STARTED:
 762                 if  (type != TYPE_FILE && type != TYPE_DIR)
 763                         return false;
 764                 *mode = ES_MODE_GET_FILE_ENTRY;
 765                 return true;
 766         case ES_MODE_GET_FILE_ENTRY:
 767                 if (type != TYPE_STREAM)
 768                         return false;
 769                 *mode = ES_MODE_GET_STRM_ENTRY;
 770                 return true;
 771         case ES_MODE_GET_STRM_ENTRY:
 772                 if (type != TYPE_EXTEND)
 773                         return false;
 774                 *mode = ES_MODE_GET_NAME_ENTRY;
 775                 return true;
 776         case ES_MODE_GET_NAME_ENTRY:
 777                 if (type == TYPE_STREAM)
 778                         return false;
 779                 if (type != TYPE_EXTEND) {
 780                         if (!(type & TYPE_CRITICAL_SEC))
 781                                 return false;
 782                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 783                 }
 784                 return true;
 785         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 786                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 787                         return false;
 788                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 789                         return false;
 790                 return true;
 791         default:
 792                 WARN_ON_ONCE(1);
 793                 return false;
 794         }
 795 }
 796
 797 struct exfat_dentry *exfat_get_dentry_cached(
 798         struct exfat_entry_set_cache *es, int num)
 799 {
 800         int off = es->start_off + num * DENTRY_SIZE;
 801         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 802         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 803
 804         return (struct exfat_dentry *)p;
 805 }
 806
 807 /*
 808  * Returns a set of dentries for a file or dir.
 809  *
 810  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 811  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 812  * changes made in this entry set to the real device.
 813  *
 814  * in:
 815  *   sb+p_dir+entry: indicates a file/dir
 816  *   type:  specifies how many dentries should be included.
 817  * return:
 818  *   pointer of entry set on success,
 819  *   NULL on failure.
 820  */
 821 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 822                 struct exfat_chain *p_dir, int entry, unsigned int type)
 823 {
 824         int ret, i, num_bh;
 825         unsigned int off, byte_offset, clu = 0;
 826         sector_t sec;
 827         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 828         struct exfat_entry_set_cache *es;
 829         struct exfat_dentry *ep;
 830         int num_entries;
 831         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 832         struct buffer_head *bh;
 833
 834         if (p_dir->dir == DIR_DELETED) {
 835                 exfat_err(sb, "access to deleted dentry");
 836                 return NULL;
 837         }
 838
 839         byte_offset = EXFAT_DEN_TO_B(entry);
 840         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
 841         if (ret)
 842                 return NULL;
 843
 844         es = kzalloc(sizeof(*es), GFP_KERNEL);
 845         if (!es)
 846                 return NULL;
 847         es->sb = sb;
 848         es->modified = false;
 849
 850         /* byte offset in cluster */
 851         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 852
 853         /* byte offset in sector */
 854         off = EXFAT_BLK_OFFSET(byte_offset, sb);
 855         es->start_off = off;
 856
 857         /* sector offset in cluster */
 858         sec = EXFAT_B_TO_BLK(byte_offset, sb);
 859         sec += exfat_cluster_to_sector(sbi, clu);
 860
 861         bh = sb_bread(sb, sec);
 862         if (!bh)
 863                 goto free_es;
 864         es->bh[es->num_bh++] = bh;
 865
 866         ep = exfat_get_dentry_cached(es, 0);
 867         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 868                 goto free_es;
 869
 870         num_entries = type == ES_ALL_ENTRIES ?
 871                 ep->dentry.file.num_ext + 1 : type;
 872         es->num_entries = num_entries;
 873
 874         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 875         for (i = 1; i < num_bh; i++) {
 876                 /* get the next sector */
 877                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 878                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 879                                 clu++;
 880                         else if (exfat_get_next_cluster(sb, &clu))
 881                                 goto free_es;
 882                         sec = exfat_cluster_to_sector(sbi, clu);
 883                 } else {
 884                         sec++;
 885                 }
 886
 887                 bh = sb_bread(sb, sec);
 888                 if (!bh)
 889                         goto free_es;
 890                 es->bh[es->num_bh++] = bh;
 891         }
 892
 893         /* validiate cached dentries */
 894         for (i = 1; i < num_entries; i++) {
 895                 ep = exfat_get_dentry_cached(es, i);
 896                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 897                         goto free_es;
 898         }
 899         return es;
 900
 901 free_es:
 902         exfat_free_dentry_set(es, false);
 903         return NULL;
 904 }
 905
 906 enum {
 907         DIRENT_STEP_FILE,
 908         DIRENT_STEP_STRM,
 909         DIRENT_STEP_NAME,
 910         DIRENT_STEP_SECD,
 911 };
 912
 913 /*
 914  * @ei:         inode info of parent directory
 915  * @p_dir:      directory structure of parent directory
 916  * @num_entries:entry size of p_uniname
 917  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 918  *              for traversing cluster chain.
 919  * @return:
 920  *   >= 0:      file directory entry position where the name exists
 921  *   -ENOENT:   entry with the name does not exist
 922  *   -EIO:      I/O error
 923  */
 924 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 925                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 926                 int num_entries, unsigned int type, struct exfat_hint *hint_opt)
 927 {
 928         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 929         int order, step, name_len = 0;
 930         int dentries_per_clu, num_empty = 0;
 931         unsigned int entry_type;
 932         unsigned short *uniname = NULL;
 933         struct exfat_chain clu;
 934         struct exfat_hint *hint_stat = &ei->hint_stat;
 935         struct exfat_hint_femp candi_empty;
 936         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 937
 938         dentries_per_clu = sbi->dentries_per_clu;
 939
 940         exfat_chain_dup(&clu, p_dir);
 941
 942         if (hint_stat->eidx) {
 943                 clu.dir = hint_stat->clu;
 944                 dentry = hint_stat->eidx;
 945                 end_eidx = dentry;
 946         }
 947
 948         candi_empty.eidx = EXFAT_HINT_NONE;
 949 rewind:
 950         order = 0;
 951         step = DIRENT_STEP_FILE;
 952         while (clu.dir != EXFAT_EOF_CLUSTER) {
 953                 i = dentry & (dentries_per_clu - 1);
 954                 for (; i < dentries_per_clu; i++, dentry++) {
 955                         struct exfat_dentry *ep;
 956                         struct buffer_head *bh;
 957
 958                         if (rewind && dentry == end_eidx)
 959                                 goto not_found;
 960
 961                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
 962                         if (!ep)
 963                                 return -EIO;
 964
 965                         entry_type = exfat_get_entry_type(ep);
 966
 967                         if (entry_type == TYPE_UNUSED ||
 968                             entry_type == TYPE_DELETED) {
 969                                 step = DIRENT_STEP_FILE;
 970
 971                                 num_empty++;
 972                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 973                                                 num_empty == 1) {
 974                                         exfat_chain_set(&candi_empty.cur,
 975                                                 clu.dir, clu.size, clu.flags);
 976                                 }
 977
 978                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 979                                                 num_empty >= num_entries) {
 980                                         candi_empty.eidx =
 981                                                 dentry - (num_empty - 1);
 982                                         WARN_ON(candi_empty.eidx < 0);
 983                                         candi_empty.count = num_empty;
 984
 985                                         if (ei->hint_femp.eidx ==
 986                                                         EXFAT_HINT_NONE ||
 987                                                 candi_empty.eidx <=
 988                                                          ei->hint_femp.eidx)
 989                                                 ei->hint_femp = candi_empty;
 990                                 }
 991
 992                                 brelse(bh);
 993                                 if (entry_type == TYPE_UNUSED)
 994                                         goto not_found;
 995                                 continue;
 996                         }
 997
 998                         num_empty = 0;
 999                         candi_empty.eidx = EXFAT_HINT_NONE;
1000
1001                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1002                                 step = DIRENT_STEP_FILE;
1003                                 hint_opt->clu = clu.dir;
1004                                 hint_opt->eidx = i;
1005                                 if (type == TYPE_ALL || type == entry_type) {
1006                                         num_ext = ep->dentry.file.num_ext;
1007                                         step = DIRENT_STEP_STRM;
1008                                 }
1009                                 brelse(bh);
1010                                 continue;
1011                         }
1012
1013                         if (entry_type == TYPE_STREAM) {
1014                                 u16 name_hash;
1015
1016                                 if (step != DIRENT_STEP_STRM) {
1017                                         step = DIRENT_STEP_FILE;
1018                                         brelse(bh);
1019                                         continue;
1020                                 }
1021                                 step = DIRENT_STEP_FILE;
1022                                 name_hash = le16_to_cpu(
1023                                                 ep->dentry.stream.name_hash);
1024                                 if (p_uniname->name_hash == name_hash &&
1025                                     p_uniname->name_len ==
1026                                                 ep->dentry.stream.name_len) {
1027                                         step = DIRENT_STEP_NAME;
1028                                         order = 1;
1029                                         name_len = 0;
1030                                 }
1031                                 brelse(bh);
1032                                 continue;
1033                         }
1034
1035                         brelse(bh);
1036                         if (entry_type == TYPE_EXTEND) {
1037                                 unsigned short entry_uniname[16], unichar;
1038
1039                                 if (step != DIRENT_STEP_NAME) {
1040                                         step = DIRENT_STEP_FILE;
1041                                         continue;
1042                                 }
1043
1044                                 if (++order == 2)
1045                                         uniname = p_uniname->name;
1046                                 else
1047                                         uniname += EXFAT_FILE_NAME_LEN;
1048
1049                                 len = exfat_extract_uni_name(ep, entry_uniname);
1050                                 name_len += len;
1051
1052                                 unichar = *(uniname+len);
1053                                 *(uniname+len) = 0x0;
1054
1055                                 if (exfat_uniname_ncmp(sb, uniname,
1056                                         entry_uniname, len)) {
1057                                         step = DIRENT_STEP_FILE;
1058                                 } else if (p_uniname->name_len == name_len) {
1059                                         if (order == num_ext)
1060                                                 goto found;
1061                                         step = DIRENT_STEP_SECD;
1062                                 }
1063
1064                                 *(uniname+len) = unichar;
1065                                 continue;
1066                         }
1067
1068                         if (entry_type &
1069                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1070                                 if (step == DIRENT_STEP_SECD) {
1071                                         if (++order == num_ext)
1072                                                 goto found;
1073                                         continue;
1074                                 }
1075                         }
1076                         step = DIRENT_STEP_FILE;
1077                 }
1078
1079                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1080                         if (--clu.size > 0)
1081                                 clu.dir++;
1082                         else
1083                                 clu.dir = EXFAT_EOF_CLUSTER;
1084                 } else {
1085                         if (exfat_get_next_cluster(sb, &clu.dir))
1086                                 return -EIO;
1087                 }
1088         }
1089
1090 not_found:
1091         /*
1092          * We started at not 0 index,so we should try to find target
1093          * from 0 index to the index we started at.
1094          */
1095         if (!rewind && end_eidx) {
1096                 rewind = 1;
1097                 dentry = 0;
1098                 clu.dir = p_dir->dir;
1099                 /* reset empty hint */
1100                 num_empty = 0;
1101                 candi_empty.eidx = EXFAT_HINT_NONE;
1102                 goto rewind;
1103         }
1104
1105         /* initialized hint_stat */
1106         hint_stat->clu = p_dir->dir;
1107         hint_stat->eidx = 0;
1108         return -ENOENT;
1109
1110 found:
1111         /* next dentry we'll find is out of this cluster */
1112         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1113                 int ret = 0;
1114
1115                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1116                         if (--clu.size > 0)
1117                                 clu.dir++;
1118                         else
1119                                 clu.dir = EXFAT_EOF_CLUSTER;
1120                 } else {
1121                         ret = exfat_get_next_cluster(sb, &clu.dir);
1122                 }
1123
1124                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1125                         /* just initialized hint_stat */
1126                         hint_stat->clu = p_dir->dir;
1127                         hint_stat->eidx = 0;
1128                         return (dentry - num_ext);
1129                 }
1130         }
1131
1132         hint_stat->clu = clu.dir;
1133         hint_stat->eidx = dentry + 1;
1134         return dentry - num_ext;
1135 }
1136
1137 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1138                 int entry, struct exfat_dentry *ep)
1139 {
1140         int i, count = 0;
1141         unsigned int type;
1142         struct exfat_dentry *ext_ep;
1143         struct buffer_head *bh;
1144
1145         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1146                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
1147                 if (!ext_ep)
1148                         return -EIO;
1149
1150                 type = exfat_get_entry_type(ext_ep);
1151                 brelse(bh);
1152                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1153                         count++;
1154                 else
1155                         break;
1156         }
1157         return count;
1158 }
1159
1160 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1161 {
1162         int i, count = 0;
1163         int dentries_per_clu;
1164         unsigned int entry_type;
1165         struct exfat_chain clu;
1166         struct exfat_dentry *ep;
1167         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1168         struct buffer_head *bh;
1169
1170         dentries_per_clu = sbi->dentries_per_clu;
1171
1172         exfat_chain_dup(&clu, p_dir);
1173
1174         while (clu.dir != EXFAT_EOF_CLUSTER) {
1175                 for (i = 0; i < dentries_per_clu; i++) {
1176                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
1177                         if (!ep)
1178                                 return -EIO;
1179                         entry_type = exfat_get_entry_type(ep);
1180                         brelse(bh);
1181
1182                         if (entry_type == TYPE_UNUSED)
1183                                 return count;
1184                         if (entry_type != TYPE_DIR)
1185                                 continue;
1186                         count++;
1187                 }
1188
1189                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1190                         if (--clu.size > 0)
1191                                 clu.dir++;
1192                         else
1193                                 clu.dir = EXFAT_EOF_CLUSTER;
1194                 } else {
1195                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1196                                 return -EIO;
1197                 }
1198         }
1199
1200         return count;
1201 }