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