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, max_dentries;
  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         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  90                                            (u64)sbi->num_clusters << dentries_per_clu_bits);
  91
  92         clu_offset = dentry >> dentries_per_clu_bits;
  93         exfat_chain_dup(&clu, &dir);
  94
  95         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  96                 clu.dir += clu_offset;
  97                 clu.size -= clu_offset;
  98         } else {
  99                 /* hint_information */
 100                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
 101                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 102                         clu_offset -= ei->hint_bmap.off;
 103                         clu.dir = ei->hint_bmap.clu;
 104                 }
 105
 106                 while (clu_offset > 0) {
 107                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 108                                 return -EIO;
 109
 110                         clu_offset--;
 111                 }
 112         }
 113
 114         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
 115                 i = dentry & (dentries_per_clu - 1);
 116
 117                 for ( ; i < dentries_per_clu; i++, dentry++) {
 118                         ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
 119                         if (!ep)
 120                                 return -EIO;
 121
 122                         type = exfat_get_entry_type(ep);
 123                         if (type == TYPE_UNUSED) {
 124                                 brelse(bh);
 125                                 break;
 126                         }
 127
 128                         if (type != TYPE_FILE && type != TYPE_DIR) {
 129                                 brelse(bh);
 130                                 continue;
 131                         }
 132
 133                         num_ext = ep->dentry.file.num_ext;
 134                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 135                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 136                                         ep->dentry.file.create_tz,
 137                                         ep->dentry.file.create_time,
 138                                         ep->dentry.file.create_date,
 139                                         ep->dentry.file.create_time_cs);
 140                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 141                                         ep->dentry.file.modify_tz,
 142                                         ep->dentry.file.modify_time,
 143                                         ep->dentry.file.modify_date,
 144                                         ep->dentry.file.modify_time_cs);
 145                         exfat_get_entry_time(sbi, &dir_entry->atime,
 146                                         ep->dentry.file.access_tz,
 147                                         ep->dentry.file.access_time,
 148                                         ep->dentry.file.access_date,
 149                                         0);
 150
 151                         *uni_name.name = 0x0;
 152                         exfat_get_uniname_from_ext_entry(sb, &clu, i,
 153                                 uni_name.name);
 154                         exfat_utf16_to_nls(sb, &uni_name,
 155                                 dir_entry->namebuf.lfn,
 156                                 dir_entry->namebuf.lfnbuf_len);
 157                         brelse(bh);
 158
 159                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
 160                         if (!ep)
 161                                 return -EIO;
 162                         dir_entry->size =
 163                                 le64_to_cpu(ep->dentry.stream.valid_size);
 164                         dir_entry->entry = dentry;
 165                         brelse(bh);
 166
 167                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
 168                         ei->hint_bmap.clu = clu.dir;
 169
 170                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 171                         return 0;
 172                 }
 173
 174                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 175                         if (--clu.size > 0)
 176                                 clu.dir++;
 177                         else
 178                                 clu.dir = EXFAT_EOF_CLUSTER;
 179                 } else {
 180                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 181                                 return -EIO;
 182                 }
 183         }
 184
 185         dir_entry->namebuf.lfn[0] = '\0';
 186         *cpos = EXFAT_DEN_TO_B(dentry);
 187         return 0;
 188 }
 189
 190 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 191 {
 192         nb->lfn = NULL;
 193         nb->lfnbuf_len = 0;
 194 }
 195
 196 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 197 {
 198         nb->lfn = __getname();
 199         if (!nb->lfn)
 200                 return -ENOMEM;
 201         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 202         return 0;
 203 }
 204
 205 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 206 {
 207         if (!nb->lfn)
 208                 return;
 209
 210         __putname(nb->lfn);
 211         exfat_init_namebuf(nb);
 212 }
 213
 214 /* skip iterating emit_dots when dir is empty */
 215 #define ITER_POS_FILLED_DOTS    (2)
 216 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
 217 {
 218         struct inode *inode = filp->f_path.dentry->d_inode;
 219         struct super_block *sb = inode->i_sb;
 220         struct inode *tmp;
 221         struct exfat_dir_entry de;
 222         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 223         struct exfat_inode_info *ei = EXFAT_I(inode);
 224         unsigned long inum;
 225         loff_t cpos, i_pos;
 226         int err = 0, fake_offset = 0;
 227
 228         exfat_init_namebuf(nb);
 229         mutex_lock(&EXFAT_SB(sb)->s_lock);
 230
 231         cpos = ctx->pos;
 232         if (!dir_emit_dots(filp, ctx))
 233                 goto unlock;
 234
 235         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 236                 cpos = 0;
 237                 fake_offset = 1;
 238         }
 239
 240         if (cpos & (DENTRY_SIZE - 1)) {
 241                 err = -ENOENT;
 242                 goto unlock;
 243         }
 244
 245         /* name buffer should be allocated before use */
 246         err = exfat_alloc_namebuf(nb);
 247         if (err)
 248                 goto unlock;
 249 get_new:
 250         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 251                 goto end_of_dir;
 252
 253         err = exfat_readdir(inode, &cpos, &de);
 254         if (err) {
 255                 /*
 256                  * At least we tried to read a sector.  Move cpos to next sector
 257                  * position (should be aligned).
 258                  */
 259                 if (err == -EIO) {
 260                         cpos += 1 << (sb->s_blocksize_bits);
 261                         cpos &= ~(sb->s_blocksize - 1);
 262                 }
 263
 264                 err = -EIO;
 265                 goto end_of_dir;
 266         }
 267
 268         if (!nb->lfn[0])
 269                 goto end_of_dir;
 270
 271         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 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         .unlocked_ioctl = exfat_ioctl,
 313 #ifdef CONFIG_COMPAT
 314         .compat_ioctl = exfat_compat_ioctl,
 315 #endif
 316         .fsync          = exfat_file_fsync,
 317 };
 318
 319 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 320 {
 321         int ret;
 322
 323         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 324
 325         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 326         if (ret)
 327                 return ret;
 328
 329         return exfat_zeroed_cluster(inode, clu->dir);
 330 }
 331
 332 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 333 {
 334         int len;
 335
 336         len = p_uniname->name_len;
 337         if (len == 0)
 338                 return -EINVAL;
 339
 340         /* 1 file entry + 1 stream entry + name entries */
 341         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 342 }
 343
 344 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 345 {
 346         if (ep->type == EXFAT_UNUSED)
 347                 return TYPE_UNUSED;
 348         if (IS_EXFAT_DELETED(ep->type))
 349                 return TYPE_DELETED;
 350         if (ep->type == EXFAT_INVAL)
 351                 return TYPE_INVALID;
 352         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 353                 if (ep->type == EXFAT_BITMAP)
 354                         return TYPE_BITMAP;
 355                 if (ep->type == EXFAT_UPCASE)
 356                         return TYPE_UPCASE;
 357                 if (ep->type == EXFAT_VOLUME)
 358                         return TYPE_VOLUME;
 359                 if (ep->type == EXFAT_FILE) {
 360                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 361                                 return TYPE_DIR;
 362                         return TYPE_FILE;
 363                 }
 364                 return TYPE_CRITICAL_PRI;
 365         }
 366         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 367                 if (ep->type == EXFAT_GUID)
 368                         return TYPE_GUID;
 369                 if (ep->type == EXFAT_PADDING)
 370                         return TYPE_PADDING;
 371                 if (ep->type == EXFAT_ACLTAB)
 372                         return TYPE_ACLTAB;
 373                 return TYPE_BENIGN_PRI;
 374         }
 375         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 376                 if (ep->type == EXFAT_STREAM)
 377                         return TYPE_STREAM;
 378                 if (ep->type == EXFAT_NAME)
 379                         return TYPE_EXTEND;
 380                 if (ep->type == EXFAT_ACL)
 381                         return TYPE_ACL;
 382                 return TYPE_CRITICAL_SEC;
 383         }
 384         return TYPE_BENIGN_SEC;
 385 }
 386
 387 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 388 {
 389         if (type == TYPE_UNUSED) {
 390                 ep->type = EXFAT_UNUSED;
 391         } else if (type == TYPE_DELETED) {
 392                 ep->type &= EXFAT_DELETE;
 393         } else if (type == TYPE_STREAM) {
 394                 ep->type = EXFAT_STREAM;
 395         } else if (type == TYPE_EXTEND) {
 396                 ep->type = EXFAT_NAME;
 397         } else if (type == TYPE_BITMAP) {
 398                 ep->type = EXFAT_BITMAP;
 399         } else if (type == TYPE_UPCASE) {
 400                 ep->type = EXFAT_UPCASE;
 401         } else if (type == TYPE_VOLUME) {
 402                 ep->type = EXFAT_VOLUME;
 403         } else if (type == TYPE_DIR) {
 404                 ep->type = EXFAT_FILE;
 405                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 406         } else if (type == TYPE_FILE) {
 407                 ep->type = EXFAT_FILE;
 408                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 409         }
 410 }
 411
 412 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 413                 unsigned char flags, unsigned int start_clu,
 414                 unsigned long long size)
 415 {
 416         exfat_set_entry_type(ep, TYPE_STREAM);
 417         ep->dentry.stream.flags = flags;
 418         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 419         ep->dentry.stream.valid_size = cpu_to_le64(size);
 420         ep->dentry.stream.size = cpu_to_le64(size);
 421 }
 422
 423 static void exfat_init_name_entry(struct exfat_dentry *ep,
 424                 unsigned short *uniname)
 425 {
 426         int i;
 427
 428         exfat_set_entry_type(ep, TYPE_EXTEND);
 429         ep->dentry.name.flags = 0x0;
 430
 431         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 432                 if (*uniname != 0x0) {
 433                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 434                         uniname++;
 435                 } else {
 436                         ep->dentry.name.unicode_0_14[i] = 0x0;
 437                 }
 438         }
 439 }
 440
 441 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 442                 int entry, unsigned int type, unsigned int start_clu,
 443                 unsigned long long size)
 444 {
 445         struct super_block *sb = inode->i_sb;
 446         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 447         struct timespec64 ts = current_time(inode);
 448         sector_t sector;
 449         struct exfat_dentry *ep;
 450         struct buffer_head *bh;
 451
 452         /*
 453          * We cannot use exfat_get_dentry_set here because file ep is not
 454          * initialized yet.
 455          */
 456         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 457         if (!ep)
 458                 return -EIO;
 459
 460         exfat_set_entry_type(ep, type);
 461         exfat_set_entry_time(sbi, &ts,
 462                         &ep->dentry.file.create_tz,
 463                         &ep->dentry.file.create_time,
 464                         &ep->dentry.file.create_date,
 465                         &ep->dentry.file.create_time_cs);
 466         exfat_set_entry_time(sbi, &ts,
 467                         &ep->dentry.file.modify_tz,
 468                         &ep->dentry.file.modify_time,
 469                         &ep->dentry.file.modify_date,
 470                         &ep->dentry.file.modify_time_cs);
 471         exfat_set_entry_time(sbi, &ts,
 472                         &ep->dentry.file.access_tz,
 473                         &ep->dentry.file.access_time,
 474                         &ep->dentry.file.access_date,
 475                         NULL);
 476
 477         exfat_update_bh(bh, IS_DIRSYNC(inode));
 478         brelse(bh);
 479
 480         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 481         if (!ep)
 482                 return -EIO;
 483
 484         exfat_init_stream_entry(ep,
 485                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 486                 start_clu, size);
 487         exfat_update_bh(bh, IS_DIRSYNC(inode));
 488         brelse(bh);
 489
 490         return 0;
 491 }
 492
 493 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 494                 int entry)
 495 {
 496         struct super_block *sb = inode->i_sb;
 497         int ret = 0;
 498         int i, num_entries;
 499         sector_t sector;
 500         u16 chksum;
 501         struct exfat_dentry *ep, *fep;
 502         struct buffer_head *fbh, *bh;
 503
 504         fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
 505         if (!fep)
 506                 return -EIO;
 507
 508         num_entries = fep->dentry.file.num_ext + 1;
 509         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 510
 511         for (i = 1; i < num_entries; i++) {
 512                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
 513                 if (!ep) {
 514                         ret = -EIO;
 515                         goto release_fbh;
 516                 }
 517                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 518                                 CS_DEFAULT);
 519                 brelse(bh);
 520         }
 521
 522         fep->dentry.file.checksum = cpu_to_le16(chksum);
 523         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 524 release_fbh:
 525         brelse(fbh);
 526         return ret;
 527 }
 528
 529 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 530                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 531 {
 532         struct super_block *sb = inode->i_sb;
 533         int i;
 534         sector_t sector;
 535         unsigned short *uniname = p_uniname->name;
 536         struct exfat_dentry *ep;
 537         struct buffer_head *bh;
 538         int sync = IS_DIRSYNC(inode);
 539
 540         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 541         if (!ep)
 542                 return -EIO;
 543
 544         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 545         exfat_update_bh(bh, sync);
 546         brelse(bh);
 547
 548         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 549         if (!ep)
 550                 return -EIO;
 551
 552         ep->dentry.stream.name_len = p_uniname->name_len;
 553         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 554         exfat_update_bh(bh, sync);
 555         brelse(bh);
 556
 557         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
 558                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 559                 if (!ep)
 560                         return -EIO;
 561
 562                 exfat_init_name_entry(ep, uniname);
 563                 exfat_update_bh(bh, sync);
 564                 brelse(bh);
 565                 uniname += EXFAT_FILE_NAME_LEN;
 566         }
 567
 568         exfat_update_dir_chksum(inode, p_dir, entry);
 569         return 0;
 570 }
 571
 572 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 573                 int entry, int order, int num_entries)
 574 {
 575         struct super_block *sb = inode->i_sb;
 576         int i;
 577         sector_t sector;
 578         struct exfat_dentry *ep;
 579         struct buffer_head *bh;
 580
 581         for (i = order; i < num_entries; i++) {
 582                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 583                 if (!ep)
 584                         return -EIO;
 585
 586                 exfat_set_entry_type(ep, TYPE_DELETED);
 587                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 588                 brelse(bh);
 589         }
 590
 591         return 0;
 592 }
 593
 594 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 595 {
 596         int chksum_type = CS_DIR_ENTRY, i;
 597         unsigned short chksum = 0;
 598         struct exfat_dentry *ep;
 599
 600         for (i = 0; i < es->num_entries; i++) {
 601                 ep = exfat_get_dentry_cached(es, i);
 602                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 603                                              chksum_type);
 604                 chksum_type = CS_DEFAULT;
 605         }
 606         ep = exfat_get_dentry_cached(es, 0);
 607         ep->dentry.file.checksum = cpu_to_le16(chksum);
 608         es->modified = true;
 609 }
 610
 611 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 612 {
 613         int i, err = 0;
 614
 615         if (es->modified)
 616                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 617
 618         for (i = 0; i < es->num_bh; i++)
 619                 if (err)
 620                         bforget(es->bh[i]);
 621                 else
 622                         brelse(es->bh[i]);
 623         kfree(es);
 624         return err;
 625 }
 626
 627 static int exfat_walk_fat_chain(struct super_block *sb,
 628                 struct exfat_chain *p_dir, unsigned int byte_offset,
 629                 unsigned int *clu)
 630 {
 631         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 632         unsigned int clu_offset;
 633         unsigned int cur_clu;
 634
 635         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 636         cur_clu = p_dir->dir;
 637
 638         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 639                 cur_clu += clu_offset;
 640         } else {
 641                 while (clu_offset > 0) {
 642                         if (exfat_get_next_cluster(sb, &cur_clu))
 643                                 return -EIO;
 644                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 645                                 exfat_fs_error(sb,
 646                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 647                                         p_dir->dir,
 648                                         EXFAT_B_TO_DEN(byte_offset));
 649                                 return -EIO;
 650                         }
 651                         clu_offset--;
 652                 }
 653         }
 654
 655         *clu = cur_clu;
 656         return 0;
 657 }
 658
 659 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 660                 int entry, sector_t *sector, int *offset)
 661 {
 662         int ret;
 663         unsigned int off, clu = 0;
 664         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 665
 666         off = EXFAT_DEN_TO_B(entry);
 667
 668         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 669         if (ret)
 670                 return ret;
 671
 672         /* byte offset in cluster */
 673         off = EXFAT_CLU_OFFSET(off, sbi);
 674
 675         /* byte offset in sector    */
 676         *offset = EXFAT_BLK_OFFSET(off, sb);
 677
 678         /* sector offset in cluster */
 679         *sector = EXFAT_B_TO_BLK(off, sb);
 680         *sector += exfat_cluster_to_sector(sbi, clu);
 681         return 0;
 682 }
 683
 684 #define EXFAT_MAX_RA_SIZE     (128*1024)
 685 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 686 {
 687         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 688         struct buffer_head *bh;
 689         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 690         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 691         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 692         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 693
 694         /* Read-ahead is not required */
 695         if (sbi->sect_per_clus == 1)
 696                 return 0;
 697
 698         if (sec < sbi->data_start_sector) {
 699                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 700                           (unsigned long long)sec, sbi->data_start_sector);
 701                 return -EIO;
 702         }
 703
 704         /* Not sector aligned with ra_count, resize ra_count to page size */
 705         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 706                 ra_count = page_ra_count;
 707
 708         bh = sb_find_get_block(sb, sec);
 709         if (!bh || !buffer_uptodate(bh)) {
 710                 unsigned int i;
 711
 712                 for (i = 0; i < ra_count; i++)
 713                         sb_breadahead(sb, (sector_t)(sec + i));
 714         }
 715         brelse(bh);
 716         return 0;
 717 }
 718
 719 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 720                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 721                 sector_t *sector)
 722 {
 723         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 724         int off;
 725         sector_t sec;
 726
 727         if (p_dir->dir == DIR_DELETED) {
 728                 exfat_err(sb, "abnormal access to deleted dentry");
 729                 return NULL;
 730         }
 731
 732         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 733                 return NULL;
 734
 735         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 736                         !(entry & (dentries_per_page - 1)))
 737                 exfat_dir_readahead(sb, sec);
 738
 739         *bh = sb_bread(sb, sec);
 740         if (!*bh)
 741                 return NULL;
 742
 743         if (sector)
 744                 *sector = sec;
 745         return (struct exfat_dentry *)((*bh)->b_data + off);
 746 }
 747
 748 enum exfat_validate_dentry_mode {
 749         ES_MODE_STARTED,
 750         ES_MODE_GET_FILE_ENTRY,
 751         ES_MODE_GET_STRM_ENTRY,
 752         ES_MODE_GET_NAME_ENTRY,
 753         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 754 };
 755
 756 static bool exfat_validate_entry(unsigned int type,
 757                 enum exfat_validate_dentry_mode *mode)
 758 {
 759         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 760                 return false;
 761
 762         switch (*mode) {
 763         case ES_MODE_STARTED:
 764                 if  (type != TYPE_FILE && type != TYPE_DIR)
 765                         return false;
 766                 *mode = ES_MODE_GET_FILE_ENTRY;
 767                 return true;
 768         case ES_MODE_GET_FILE_ENTRY:
 769                 if (type != TYPE_STREAM)
 770                         return false;
 771                 *mode = ES_MODE_GET_STRM_ENTRY;
 772                 return true;
 773         case ES_MODE_GET_STRM_ENTRY:
 774                 if (type != TYPE_EXTEND)
 775                         return false;
 776                 *mode = ES_MODE_GET_NAME_ENTRY;
 777                 return true;
 778         case ES_MODE_GET_NAME_ENTRY:
 779                 if (type == TYPE_STREAM)
 780                         return false;
 781                 if (type != TYPE_EXTEND) {
 782                         if (!(type & TYPE_CRITICAL_SEC))
 783                                 return false;
 784                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 785                 }
 786                 return true;
 787         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 788                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 789                         return false;
 790                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 791                         return false;
 792                 return true;
 793         default:
 794                 WARN_ON_ONCE(1);
 795                 return false;
 796         }
 797 }
 798
 799 struct exfat_dentry *exfat_get_dentry_cached(
 800         struct exfat_entry_set_cache *es, int num)
 801 {
 802         int off = es->start_off + num * DENTRY_SIZE;
 803         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 804         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 805
 806         return (struct exfat_dentry *)p;
 807 }
 808
 809 /*
 810  * Returns a set of dentries for a file or dir.
 811  *
 812  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 813  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 814  * changes made in this entry set to the real device.
 815  *
 816  * in:
 817  *   sb+p_dir+entry: indicates a file/dir
 818  *   type:  specifies how many dentries should be included.
 819  * return:
 820  *   pointer of entry set on success,
 821  *   NULL on failure.
 822  */
 823 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 824                 struct exfat_chain *p_dir, int entry, unsigned int type)
 825 {
 826         int ret, i, num_bh;
 827         unsigned int off, byte_offset, clu = 0;
 828         sector_t sec;
 829         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 830         struct exfat_entry_set_cache *es;
 831         struct exfat_dentry *ep;
 832         int num_entries;
 833         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 834         struct buffer_head *bh;
 835
 836         if (p_dir->dir == DIR_DELETED) {
 837                 exfat_err(sb, "access to deleted dentry");
 838                 return NULL;
 839         }
 840
 841         byte_offset = EXFAT_DEN_TO_B(entry);
 842         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
 843         if (ret)
 844                 return NULL;
 845
 846         es = kzalloc(sizeof(*es), GFP_KERNEL);
 847         if (!es)
 848                 return NULL;
 849         es->sb = sb;
 850         es->modified = false;
 851
 852         /* byte offset in cluster */
 853         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 854
 855         /* byte offset in sector */
 856         off = EXFAT_BLK_OFFSET(byte_offset, sb);
 857         es->start_off = off;
 858
 859         /* sector offset in cluster */
 860         sec = EXFAT_B_TO_BLK(byte_offset, sb);
 861         sec += exfat_cluster_to_sector(sbi, clu);
 862
 863         bh = sb_bread(sb, sec);
 864         if (!bh)
 865                 goto free_es;
 866         es->bh[es->num_bh++] = bh;
 867
 868         ep = exfat_get_dentry_cached(es, 0);
 869         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 870                 goto free_es;
 871
 872         num_entries = type == ES_ALL_ENTRIES ?
 873                 ep->dentry.file.num_ext + 1 : type;
 874         es->num_entries = num_entries;
 875
 876         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 877         for (i = 1; i < num_bh; i++) {
 878                 /* get the next sector */
 879                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 880                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 881                                 clu++;
 882                         else if (exfat_get_next_cluster(sb, &clu))
 883                                 goto free_es;
 884                         sec = exfat_cluster_to_sector(sbi, clu);
 885                 } else {
 886                         sec++;
 887                 }
 888
 889                 bh = sb_bread(sb, sec);
 890                 if (!bh)
 891                         goto free_es;
 892                 es->bh[es->num_bh++] = bh;
 893         }
 894
 895         /* validiate cached dentries */
 896         for (i = 1; i < num_entries; i++) {
 897                 ep = exfat_get_dentry_cached(es, i);
 898                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 899                         goto free_es;
 900         }
 901         return es;
 902
 903 free_es:
 904         exfat_free_dentry_set(es, false);
 905         return NULL;
 906 }
 907
 908 enum {
 909         DIRENT_STEP_FILE,
 910         DIRENT_STEP_STRM,
 911         DIRENT_STEP_NAME,
 912         DIRENT_STEP_SECD,
 913 };
 914
 915 /*
 916  * @ei:         inode info of parent directory
 917  * @p_dir:      directory structure of parent directory
 918  * @num_entries:entry size of p_uniname
 919  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 920  *              for traversing cluster chain.
 921  * @return:
 922  *   >= 0:      file directory entry position where the name exists
 923  *   -ENOENT:   entry with the name does not exist
 924  *   -EIO:      I/O error
 925  */
 926 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 927                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 928                 int num_entries, unsigned int type, struct exfat_hint *hint_opt)
 929 {
 930         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 931         int order, step, name_len = 0;
 932         int dentries_per_clu, num_empty = 0;
 933         unsigned int entry_type;
 934         unsigned short *uniname = NULL;
 935         struct exfat_chain clu;
 936         struct exfat_hint *hint_stat = &ei->hint_stat;
 937         struct exfat_hint_femp candi_empty;
 938         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 939
 940         dentries_per_clu = sbi->dentries_per_clu;
 941
 942         exfat_chain_dup(&clu, p_dir);
 943
 944         if (hint_stat->eidx) {
 945                 clu.dir = hint_stat->clu;
 946                 dentry = hint_stat->eidx;
 947                 end_eidx = dentry;
 948         }
 949
 950         candi_empty.eidx = EXFAT_HINT_NONE;
 951 rewind:
 952         order = 0;
 953         step = DIRENT_STEP_FILE;
 954         while (clu.dir != EXFAT_EOF_CLUSTER) {
 955                 i = dentry & (dentries_per_clu - 1);
 956                 for (; i < dentries_per_clu; i++, dentry++) {
 957                         struct exfat_dentry *ep;
 958                         struct buffer_head *bh;
 959
 960                         if (rewind && dentry == end_eidx)
 961                                 goto not_found;
 962
 963                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
 964                         if (!ep)
 965                                 return -EIO;
 966
 967                         entry_type = exfat_get_entry_type(ep);
 968
 969                         if (entry_type == TYPE_UNUSED ||
 970                             entry_type == TYPE_DELETED) {
 971                                 step = DIRENT_STEP_FILE;
 972
 973                                 num_empty++;
 974                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 975                                                 num_empty == 1) {
 976                                         exfat_chain_set(&candi_empty.cur,
 977                                                 clu.dir, clu.size, clu.flags);
 978                                 }
 979
 980                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 981                                                 num_empty >= num_entries) {
 982                                         candi_empty.eidx =
 983                                                 dentry - (num_empty - 1);
 984                                         WARN_ON(candi_empty.eidx < 0);
 985                                         candi_empty.count = num_empty;
 986
 987                                         if (ei->hint_femp.eidx ==
 988                                                         EXFAT_HINT_NONE ||
 989                                                 candi_empty.eidx <=
 990                                                          ei->hint_femp.eidx)
 991                                                 ei->hint_femp = candi_empty;
 992                                 }
 993
 994                                 brelse(bh);
 995                                 if (entry_type == TYPE_UNUSED)
 996                                         goto not_found;
 997                                 continue;
 998                         }
 999
1000                         num_empty = 0;
1001                         candi_empty.eidx = EXFAT_HINT_NONE;
1002
1003                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1004                                 step = DIRENT_STEP_FILE;
1005                                 hint_opt->clu = clu.dir;
1006                                 hint_opt->eidx = i;
1007                                 if (type == TYPE_ALL || type == entry_type) {
1008                                         num_ext = ep->dentry.file.num_ext;
1009                                         step = DIRENT_STEP_STRM;
1010                                 }
1011                                 brelse(bh);
1012                                 continue;
1013                         }
1014
1015                         if (entry_type == TYPE_STREAM) {
1016                                 u16 name_hash;
1017
1018                                 if (step != DIRENT_STEP_STRM) {
1019                                         step = DIRENT_STEP_FILE;
1020                                         brelse(bh);
1021                                         continue;
1022                                 }
1023                                 step = DIRENT_STEP_FILE;
1024                                 name_hash = le16_to_cpu(
1025                                                 ep->dentry.stream.name_hash);
1026                                 if (p_uniname->name_hash == name_hash &&
1027                                     p_uniname->name_len ==
1028                                                 ep->dentry.stream.name_len) {
1029                                         step = DIRENT_STEP_NAME;
1030                                         order = 1;
1031                                         name_len = 0;
1032                                 }
1033                                 brelse(bh);
1034                                 continue;
1035                         }
1036
1037                         brelse(bh);
1038                         if (entry_type == TYPE_EXTEND) {
1039                                 unsigned short entry_uniname[16], unichar;
1040
1041                                 if (step != DIRENT_STEP_NAME) {
1042                                         step = DIRENT_STEP_FILE;
1043                                         continue;
1044                                 }
1045
1046                                 if (++order == 2)
1047                                         uniname = p_uniname->name;
1048                                 else
1049                                         uniname += EXFAT_FILE_NAME_LEN;
1050
1051                                 len = exfat_extract_uni_name(ep, entry_uniname);
1052                                 name_len += len;
1053
1054                                 unichar = *(uniname+len);
1055                                 *(uniname+len) = 0x0;
1056
1057                                 if (exfat_uniname_ncmp(sb, uniname,
1058                                         entry_uniname, len)) {
1059                                         step = DIRENT_STEP_FILE;
1060                                 } else if (p_uniname->name_len == name_len) {
1061                                         if (order == num_ext)
1062                                                 goto found;
1063                                         step = DIRENT_STEP_SECD;
1064                                 }
1065
1066                                 *(uniname+len) = unichar;
1067                                 continue;
1068                         }
1069
1070                         if (entry_type &
1071                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1072                                 if (step == DIRENT_STEP_SECD) {
1073                                         if (++order == num_ext)
1074                                                 goto found;
1075                                         continue;
1076                                 }
1077                         }
1078                         step = DIRENT_STEP_FILE;
1079                 }
1080
1081                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1082                         if (--clu.size > 0)
1083                                 clu.dir++;
1084                         else
1085                                 clu.dir = EXFAT_EOF_CLUSTER;
1086                 } else {
1087                         if (exfat_get_next_cluster(sb, &clu.dir))
1088                                 return -EIO;
1089                 }
1090         }
1091
1092 not_found:
1093         /*
1094          * We started at not 0 index,so we should try to find target
1095          * from 0 index to the index we started at.
1096          */
1097         if (!rewind && end_eidx) {
1098                 rewind = 1;
1099                 dentry = 0;
1100                 clu.dir = p_dir->dir;
1101                 /* reset empty hint */
1102                 num_empty = 0;
1103                 candi_empty.eidx = EXFAT_HINT_NONE;
1104                 goto rewind;
1105         }
1106
1107         /* initialized hint_stat */
1108         hint_stat->clu = p_dir->dir;
1109         hint_stat->eidx = 0;
1110         return -ENOENT;
1111
1112 found:
1113         /* next dentry we'll find is out of this cluster */
1114         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1115                 int ret = 0;
1116
1117                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1118                         if (--clu.size > 0)
1119                                 clu.dir++;
1120                         else
1121                                 clu.dir = EXFAT_EOF_CLUSTER;
1122                 } else {
1123                         ret = exfat_get_next_cluster(sb, &clu.dir);
1124                 }
1125
1126                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1127                         /* just initialized hint_stat */
1128                         hint_stat->clu = p_dir->dir;
1129                         hint_stat->eidx = 0;
1130                         return (dentry - num_ext);
1131                 }
1132         }
1133
1134         hint_stat->clu = clu.dir;
1135         hint_stat->eidx = dentry + 1;
1136         return dentry - num_ext;
1137 }
1138
1139 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1140                 int entry, struct exfat_dentry *ep)
1141 {
1142         int i, count = 0;
1143         unsigned int type;
1144         struct exfat_dentry *ext_ep;
1145         struct buffer_head *bh;
1146
1147         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1148                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
1149                 if (!ext_ep)
1150                         return -EIO;
1151
1152                 type = exfat_get_entry_type(ext_ep);
1153                 brelse(bh);
1154                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1155                         count++;
1156                 else
1157                         break;
1158         }
1159         return count;
1160 }
1161
1162 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1163 {
1164         int i, count = 0;
1165         int dentries_per_clu;
1166         unsigned int entry_type;
1167         struct exfat_chain clu;
1168         struct exfat_dentry *ep;
1169         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1170         struct buffer_head *bh;
1171
1172         dentries_per_clu = sbi->dentries_per_clu;
1173
1174         exfat_chain_dup(&clu, p_dir);
1175
1176         while (clu.dir != EXFAT_EOF_CLUSTER) {
1177                 for (i = 0; i < dentries_per_clu; i++) {
1178                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
1179                         if (!ep)
1180                                 return -EIO;
1181                         entry_type = exfat_get_entry_type(ep);
1182                         brelse(bh);
1183
1184                         if (entry_type == TYPE_UNUSED)
1185                                 return count;
1186                         if (entry_type != TYPE_DIR)
1187                                 continue;
1188                         count++;
1189                 }
1190
1191                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1192                         if (--clu.size > 0)
1193                                 clu.dir++;
1194                         else
1195                                 clu.dir = EXFAT_EOF_CLUSTER;
1196                 } else {
1197                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1198                                 return -EIO;
1199                 }
1200         }
1201
1202         return count;
1203 }