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         struct exfat_chain dir, clu;
  68         struct exfat_uni_name uni_name;
  69         struct exfat_dentry *ep;
  70         struct super_block *sb = inode->i_sb;
  71         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  72         struct exfat_inode_info *ei = EXFAT_I(inode);
  73         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  74         struct buffer_head *bh;
  75
  76         /* check if the given file ID is opened */
  77         if (ei->type != TYPE_DIR)
  78                 return -EPERM;
  79
  80         if (ei->entry == -1)
  81                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  82         else
  83                 exfat_chain_set(&dir, ei->start_clu,
  84                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  85
  86         dentries_per_clu = sbi->dentries_per_clu;
  87         dentries_per_clu_bits = ilog2(dentries_per_clu);
  88         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  89                                            (u64)sbi->num_clusters << dentries_per_clu_bits);
  90
  91         clu_offset = dentry >> dentries_per_clu_bits;
  92         exfat_chain_dup(&clu, &dir);
  93
  94         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  95                 clu.dir += clu_offset;
  96                 clu.size -= clu_offset;
  97         } else {
  98                 /* hint_information */
  99                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
 100                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 101                         clu_offset -= ei->hint_bmap.off;
 102                         clu.dir = ei->hint_bmap.clu;
 103                 }
 104
 105                 while (clu_offset > 0) {
 106                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 107                                 return -EIO;
 108
 109                         clu_offset--;
 110                 }
 111         }
 112
 113         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
 114                 i = dentry & (dentries_per_clu - 1);
 115
 116                 for ( ; i < dentries_per_clu; i++, dentry++) {
 117                         ep = exfat_get_dentry(sb, &clu, i, &bh);
 118                         if (!ep)
 119                                 return -EIO;
 120
 121                         type = exfat_get_entry_type(ep);
 122                         if (type == TYPE_UNUSED) {
 123                                 brelse(bh);
 124                                 break;
 125                         }
 126
 127                         if (type != TYPE_FILE && type != TYPE_DIR) {
 128                                 brelse(bh);
 129                                 continue;
 130                         }
 131
 132                         num_ext = ep->dentry.file.num_ext;
 133                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 134                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 135                                         ep->dentry.file.create_tz,
 136                                         ep->dentry.file.create_time,
 137                                         ep->dentry.file.create_date,
 138                                         ep->dentry.file.create_time_cs);
 139                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 140                                         ep->dentry.file.modify_tz,
 141                                         ep->dentry.file.modify_time,
 142                                         ep->dentry.file.modify_date,
 143                                         ep->dentry.file.modify_time_cs);
 144                         exfat_get_entry_time(sbi, &dir_entry->atime,
 145                                         ep->dentry.file.access_tz,
 146                                         ep->dentry.file.access_time,
 147                                         ep->dentry.file.access_date,
 148                                         0);
 149
 150                         *uni_name.name = 0x0;
 151                         exfat_get_uniname_from_ext_entry(sb, &clu, i,
 152                                 uni_name.name);
 153                         exfat_utf16_to_nls(sb, &uni_name,
 154                                 dir_entry->namebuf.lfn,
 155                                 dir_entry->namebuf.lfnbuf_len);
 156                         brelse(bh);
 157
 158                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh);
 159                         if (!ep)
 160                                 return -EIO;
 161                         dir_entry->size =
 162                                 le64_to_cpu(ep->dentry.stream.valid_size);
 163                         dir_entry->entry = dentry;
 164                         brelse(bh);
 165
 166                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
 167                         ei->hint_bmap.clu = clu.dir;
 168
 169                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 170                         return 0;
 171                 }
 172
 173                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 174                         if (--clu.size > 0)
 175                                 clu.dir++;
 176                         else
 177                                 clu.dir = EXFAT_EOF_CLUSTER;
 178                 } else {
 179                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 180                                 return -EIO;
 181                 }
 182         }
 183
 184         dir_entry->namebuf.lfn[0] = '\0';
 185         *cpos = EXFAT_DEN_TO_B(dentry);
 186         return 0;
 187 }
 188
 189 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 190 {
 191         nb->lfn = NULL;
 192         nb->lfnbuf_len = 0;
 193 }
 194
 195 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 196 {
 197         nb->lfn = __getname();
 198         if (!nb->lfn)
 199                 return -ENOMEM;
 200         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 201         return 0;
 202 }
 203
 204 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 205 {
 206         if (!nb->lfn)
 207                 return;
 208
 209         __putname(nb->lfn);
 210         exfat_init_namebuf(nb);
 211 }
 212
 213 /* skip iterating emit_dots when dir is empty */
 214 #define ITER_POS_FILLED_DOTS    (2)
 215 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
 216 {
 217         struct inode *inode = filp->f_path.dentry->d_inode;
 218         struct super_block *sb = inode->i_sb;
 219         struct inode *tmp;
 220         struct exfat_dir_entry de;
 221         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 222         struct exfat_inode_info *ei = EXFAT_I(inode);
 223         unsigned long inum;
 224         loff_t cpos, i_pos;
 225         int err = 0, fake_offset = 0;
 226
 227         exfat_init_namebuf(nb);
 228         mutex_lock(&EXFAT_SB(sb)->s_lock);
 229
 230         cpos = ctx->pos;
 231         if (!dir_emit_dots(filp, ctx))
 232                 goto unlock;
 233
 234         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 235                 cpos = 0;
 236                 fake_offset = 1;
 237         }
 238
 239         if (cpos & (DENTRY_SIZE - 1)) {
 240                 err = -ENOENT;
 241                 goto unlock;
 242         }
 243
 244         /* name buffer should be allocated before use */
 245         err = exfat_alloc_namebuf(nb);
 246         if (err)
 247                 goto unlock;
 248 get_new:
 249         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 250                 goto end_of_dir;
 251
 252         err = exfat_readdir(inode, &cpos, &de);
 253         if (err) {
 254                 /*
 255                  * At least we tried to read a sector.  Move cpos to next sector
 256                  * position (should be aligned).
 257                  */
 258                 if (err == -EIO) {
 259                         cpos += 1 << (sb->s_blocksize_bits);
 260                         cpos &= ~(sb->s_blocksize - 1);
 261                 }
 262
 263                 err = -EIO;
 264                 goto end_of_dir;
 265         }
 266
 267         if (!nb->lfn[0])
 268                 goto end_of_dir;
 269
 270         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 271         tmp = exfat_iget(sb, i_pos);
 272         if (tmp) {
 273                 inum = tmp->i_ino;
 274                 iput(tmp);
 275         } else {
 276                 inum = iunique(sb, EXFAT_ROOT_INO);
 277         }
 278
 279         /*
 280          * Before calling dir_emit(), sb_lock should be released.
 281          * Because page fault can occur in dir_emit() when the size
 282          * of buffer given from user is larger than one page size.
 283          */
 284         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 285         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 286                         (de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
 287                 goto out_unlocked;
 288         mutex_lock(&EXFAT_SB(sb)->s_lock);
 289         ctx->pos = cpos;
 290         goto get_new;
 291
 292 end_of_dir:
 293         if (!cpos && fake_offset)
 294                 cpos = ITER_POS_FILLED_DOTS;
 295         ctx->pos = cpos;
 296 unlock:
 297         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 298 out_unlocked:
 299         /*
 300          * To improve performance, free namebuf after unlock sb_lock.
 301          * If namebuf is not allocated, this function do nothing
 302          */
 303         exfat_free_namebuf(nb);
 304         return err;
 305 }
 306
 307 const struct file_operations exfat_dir_operations = {
 308         .llseek         = generic_file_llseek,
 309         .read           = generic_read_dir,
 310         .iterate        = exfat_iterate,
 311         .unlocked_ioctl = exfat_ioctl,
 312 #ifdef CONFIG_COMPAT
 313         .compat_ioctl = exfat_compat_ioctl,
 314 #endif
 315         .fsync          = exfat_file_fsync,
 316 };
 317
 318 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 319 {
 320         int ret;
 321
 322         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 323
 324         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 325         if (ret)
 326                 return ret;
 327
 328         return exfat_zeroed_cluster(inode, clu->dir);
 329 }
 330
 331 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 332 {
 333         int len;
 334
 335         len = p_uniname->name_len;
 336         if (len == 0)
 337                 return -EINVAL;
 338
 339         /* 1 file entry + 1 stream entry + name entries */
 340         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 341 }
 342
 343 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 344 {
 345         if (ep->type == EXFAT_UNUSED)
 346                 return TYPE_UNUSED;
 347         if (IS_EXFAT_DELETED(ep->type))
 348                 return TYPE_DELETED;
 349         if (ep->type == EXFAT_INVAL)
 350                 return TYPE_INVALID;
 351         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 352                 if (ep->type == EXFAT_BITMAP)
 353                         return TYPE_BITMAP;
 354                 if (ep->type == EXFAT_UPCASE)
 355                         return TYPE_UPCASE;
 356                 if (ep->type == EXFAT_VOLUME)
 357                         return TYPE_VOLUME;
 358                 if (ep->type == EXFAT_FILE) {
 359                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 360                                 return TYPE_DIR;
 361                         return TYPE_FILE;
 362                 }
 363                 return TYPE_CRITICAL_PRI;
 364         }
 365         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 366                 if (ep->type == EXFAT_GUID)
 367                         return TYPE_GUID;
 368                 if (ep->type == EXFAT_PADDING)
 369                         return TYPE_PADDING;
 370                 if (ep->type == EXFAT_ACLTAB)
 371                         return TYPE_ACLTAB;
 372                 return TYPE_BENIGN_PRI;
 373         }
 374         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 375                 if (ep->type == EXFAT_STREAM)
 376                         return TYPE_STREAM;
 377                 if (ep->type == EXFAT_NAME)
 378                         return TYPE_EXTEND;
 379                 if (ep->type == EXFAT_ACL)
 380                         return TYPE_ACL;
 381                 return TYPE_CRITICAL_SEC;
 382         }
 383         return TYPE_BENIGN_SEC;
 384 }
 385
 386 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 387 {
 388         if (type == TYPE_UNUSED) {
 389                 ep->type = EXFAT_UNUSED;
 390         } else if (type == TYPE_DELETED) {
 391                 ep->type &= EXFAT_DELETE;
 392         } else if (type == TYPE_STREAM) {
 393                 ep->type = EXFAT_STREAM;
 394         } else if (type == TYPE_EXTEND) {
 395                 ep->type = EXFAT_NAME;
 396         } else if (type == TYPE_BITMAP) {
 397                 ep->type = EXFAT_BITMAP;
 398         } else if (type == TYPE_UPCASE) {
 399                 ep->type = EXFAT_UPCASE;
 400         } else if (type == TYPE_VOLUME) {
 401                 ep->type = EXFAT_VOLUME;
 402         } else if (type == TYPE_DIR) {
 403                 ep->type = EXFAT_FILE;
 404                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 405         } else if (type == TYPE_FILE) {
 406                 ep->type = EXFAT_FILE;
 407                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 408         }
 409 }
 410
 411 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 412                 unsigned char flags, unsigned int start_clu,
 413                 unsigned long long size)
 414 {
 415         exfat_set_entry_type(ep, TYPE_STREAM);
 416         ep->dentry.stream.flags = flags;
 417         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 418         ep->dentry.stream.valid_size = cpu_to_le64(size);
 419         ep->dentry.stream.size = cpu_to_le64(size);
 420 }
 421
 422 static void exfat_init_name_entry(struct exfat_dentry *ep,
 423                 unsigned short *uniname)
 424 {
 425         int i;
 426
 427         exfat_set_entry_type(ep, TYPE_EXTEND);
 428         ep->dentry.name.flags = 0x0;
 429
 430         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 431                 if (*uniname != 0x0) {
 432                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 433                         uniname++;
 434                 } else {
 435                         ep->dentry.name.unicode_0_14[i] = 0x0;
 436                 }
 437         }
 438 }
 439
 440 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 441                 int entry, unsigned int type, unsigned int start_clu,
 442                 unsigned long long size)
 443 {
 444         struct super_block *sb = inode->i_sb;
 445         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 446         struct timespec64 ts = current_time(inode);
 447         struct exfat_dentry *ep;
 448         struct buffer_head *bh;
 449
 450         /*
 451          * We cannot use exfat_get_dentry_set here because file ep is not
 452          * initialized yet.
 453          */
 454         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
 455         if (!ep)
 456                 return -EIO;
 457
 458         exfat_set_entry_type(ep, type);
 459         exfat_set_entry_time(sbi, &ts,
 460                         &ep->dentry.file.create_tz,
 461                         &ep->dentry.file.create_time,
 462                         &ep->dentry.file.create_date,
 463                         &ep->dentry.file.create_time_cs);
 464         exfat_set_entry_time(sbi, &ts,
 465                         &ep->dentry.file.modify_tz,
 466                         &ep->dentry.file.modify_time,
 467                         &ep->dentry.file.modify_date,
 468                         &ep->dentry.file.modify_time_cs);
 469         exfat_set_entry_time(sbi, &ts,
 470                         &ep->dentry.file.access_tz,
 471                         &ep->dentry.file.access_time,
 472                         &ep->dentry.file.access_date,
 473                         NULL);
 474
 475         exfat_update_bh(bh, IS_DIRSYNC(inode));
 476         brelse(bh);
 477
 478         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
 479         if (!ep)
 480                 return -EIO;
 481
 482         exfat_init_stream_entry(ep,
 483                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 484                 start_clu, size);
 485         exfat_update_bh(bh, IS_DIRSYNC(inode));
 486         brelse(bh);
 487
 488         return 0;
 489 }
 490
 491 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 492                 int entry)
 493 {
 494         struct super_block *sb = inode->i_sb;
 495         int ret = 0;
 496         int i, num_entries;
 497         u16 chksum;
 498         struct exfat_dentry *ep, *fep;
 499         struct buffer_head *fbh, *bh;
 500
 501         fep = exfat_get_dentry(sb, p_dir, entry, &fbh);
 502         if (!fep)
 503                 return -EIO;
 504
 505         num_entries = fep->dentry.file.num_ext + 1;
 506         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 507
 508         for (i = 1; i < num_entries; i++) {
 509                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 510                 if (!ep) {
 511                         ret = -EIO;
 512                         goto release_fbh;
 513                 }
 514                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 515                                 CS_DEFAULT);
 516                 brelse(bh);
 517         }
 518
 519         fep->dentry.file.checksum = cpu_to_le16(chksum);
 520         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 521 release_fbh:
 522         brelse(fbh);
 523         return ret;
 524 }
 525
 526 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 527                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 528 {
 529         struct super_block *sb = inode->i_sb;
 530         int i;
 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);
 537         if (!ep)
 538                 return -EIO;
 539
 540         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 541         exfat_update_bh(bh, sync);
 542         brelse(bh);
 543
 544         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
 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(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);
 555                 if (!ep)
 556                         return -EIO;
 557
 558                 exfat_init_name_entry(ep, uniname);
 559                 exfat_update_bh(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         struct exfat_dentry *ep;
 574         struct buffer_head *bh;
 575
 576         for (i = order; i < num_entries; i++) {
 577                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 578                 if (!ep)
 579                         return -EIO;
 580
 581                 exfat_set_entry_type(ep, TYPE_DELETED);
 582                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 583                 brelse(bh);
 584         }
 585
 586         return 0;
 587 }
 588
 589 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 590 {
 591         int chksum_type = CS_DIR_ENTRY, i;
 592         unsigned short chksum = 0;
 593         struct exfat_dentry *ep;
 594
 595         for (i = 0; i < es->num_entries; i++) {
 596                 ep = exfat_get_dentry_cached(es, i);
 597                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 598                                              chksum_type);
 599                 chksum_type = CS_DEFAULT;
 600         }
 601         ep = exfat_get_dentry_cached(es, 0);
 602         ep->dentry.file.checksum = cpu_to_le16(chksum);
 603         es->modified = true;
 604 }
 605
 606 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 607 {
 608         int i, err = 0;
 609
 610         if (es->modified)
 611                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 612
 613         for (i = 0; i < es->num_bh; i++)
 614                 if (err)
 615                         bforget(es->bh[i]);
 616                 else
 617                         brelse(es->bh[i]);
 618         kfree(es);
 619         return err;
 620 }
 621
 622 static int exfat_walk_fat_chain(struct super_block *sb,
 623                 struct exfat_chain *p_dir, unsigned int byte_offset,
 624                 unsigned int *clu)
 625 {
 626         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 627         unsigned int clu_offset;
 628         unsigned int cur_clu;
 629
 630         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 631         cur_clu = p_dir->dir;
 632
 633         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 634                 cur_clu += clu_offset;
 635         } else {
 636                 while (clu_offset > 0) {
 637                         if (exfat_get_next_cluster(sb, &cur_clu))
 638                                 return -EIO;
 639                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 640                                 exfat_fs_error(sb,
 641                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 642                                         p_dir->dir,
 643                                         EXFAT_B_TO_DEN(byte_offset));
 644                                 return -EIO;
 645                         }
 646                         clu_offset--;
 647                 }
 648         }
 649
 650         *clu = cur_clu;
 651         return 0;
 652 }
 653
 654 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 655                                int entry, sector_t *sector, int *offset)
 656 {
 657         int ret;
 658         unsigned int off, clu = 0;
 659         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 660
 661         off = EXFAT_DEN_TO_B(entry);
 662
 663         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 664         if (ret)
 665                 return ret;
 666
 667         /* byte offset in cluster */
 668         off = EXFAT_CLU_OFFSET(off, sbi);
 669
 670         /* byte offset in sector    */
 671         *offset = EXFAT_BLK_OFFSET(off, sb);
 672
 673         /* sector offset in cluster */
 674         *sector = EXFAT_B_TO_BLK(off, sb);
 675         *sector += exfat_cluster_to_sector(sbi, clu);
 676         return 0;
 677 }
 678
 679 #define EXFAT_MAX_RA_SIZE     (128*1024)
 680 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 681 {
 682         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 683         struct buffer_head *bh;
 684         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 685         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 686         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 687         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 688
 689         /* Read-ahead is not required */
 690         if (sbi->sect_per_clus == 1)
 691                 return 0;
 692
 693         if (sec < sbi->data_start_sector) {
 694                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 695                           (unsigned long long)sec, sbi->data_start_sector);
 696                 return -EIO;
 697         }
 698
 699         /* Not sector aligned with ra_count, resize ra_count to page size */
 700         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 701                 ra_count = page_ra_count;
 702
 703         bh = sb_find_get_block(sb, sec);
 704         if (!bh || !buffer_uptodate(bh)) {
 705                 unsigned int i;
 706
 707                 for (i = 0; i < ra_count; i++)
 708                         sb_breadahead(sb, (sector_t)(sec + i));
 709         }
 710         brelse(bh);
 711         return 0;
 712 }
 713
 714 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 715                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
 716 {
 717         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 718         int off;
 719         sector_t sec;
 720
 721         if (p_dir->dir == DIR_DELETED) {
 722                 exfat_err(sb, "abnormal access to deleted dentry");
 723                 return NULL;
 724         }
 725
 726         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 727                 return NULL;
 728
 729         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 730                         !(entry & (dentries_per_page - 1)))
 731                 exfat_dir_readahead(sb, sec);
 732
 733         *bh = sb_bread(sb, sec);
 734         if (!*bh)
 735                 return NULL;
 736
 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         /* validate 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  * @ei:         inode info of parent directory
 909  * @p_dir:      directory structure of parent directory
 910  * @num_entries:entry size of p_uniname
 911  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 912  *              for traversing cluster chain.
 913  * @return:
 914  *   >= 0:      file directory entry position where the name exists
 915  *   -ENOENT:   entry with the name does not exist
 916  *   -EIO:      I/O error
 917  */
 918 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 919                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 920                 int num_entries, unsigned int type, struct exfat_hint *hint_opt)
 921 {
 922         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 923         int order, step, name_len = 0;
 924         int dentries_per_clu, num_empty = 0;
 925         unsigned int entry_type;
 926         unsigned short *uniname = NULL;
 927         struct exfat_chain clu;
 928         struct exfat_hint *hint_stat = &ei->hint_stat;
 929         struct exfat_hint_femp candi_empty;
 930         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 931
 932         dentries_per_clu = sbi->dentries_per_clu;
 933
 934         exfat_chain_dup(&clu, p_dir);
 935
 936         if (hint_stat->eidx) {
 937                 clu.dir = hint_stat->clu;
 938                 dentry = hint_stat->eidx;
 939                 end_eidx = dentry;
 940         }
 941
 942         candi_empty.eidx = EXFAT_HINT_NONE;
 943 rewind:
 944         order = 0;
 945         step = DIRENT_STEP_FILE;
 946         while (clu.dir != EXFAT_EOF_CLUSTER) {
 947                 i = dentry & (dentries_per_clu - 1);
 948                 for (; i < dentries_per_clu; i++, dentry++) {
 949                         struct exfat_dentry *ep;
 950                         struct buffer_head *bh;
 951
 952                         if (rewind && dentry == end_eidx)
 953                                 goto not_found;
 954
 955                         ep = exfat_get_dentry(sb, &clu, i, &bh);
 956                         if (!ep)
 957                                 return -EIO;
 958
 959                         entry_type = exfat_get_entry_type(ep);
 960
 961                         if (entry_type == TYPE_UNUSED ||
 962                             entry_type == TYPE_DELETED) {
 963                                 step = DIRENT_STEP_FILE;
 964
 965                                 num_empty++;
 966                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 967                                                 num_empty == 1) {
 968                                         exfat_chain_set(&candi_empty.cur,
 969                                                 clu.dir, clu.size, clu.flags);
 970                                 }
 971
 972                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 973                                                 num_empty >= num_entries) {
 974                                         candi_empty.eidx =
 975                                                 dentry - (num_empty - 1);
 976                                         WARN_ON(candi_empty.eidx < 0);
 977                                         candi_empty.count = num_empty;
 978
 979                                         if (ei->hint_femp.eidx ==
 980                                                         EXFAT_HINT_NONE ||
 981                                                 candi_empty.eidx <=
 982                                                          ei->hint_femp.eidx)
 983                                                 ei->hint_femp = candi_empty;
 984                                 }
 985
 986                                 brelse(bh);
 987                                 if (entry_type == TYPE_UNUSED)
 988                                         goto not_found;
 989                                 continue;
 990                         }
 991
 992                         num_empty = 0;
 993                         candi_empty.eidx = EXFAT_HINT_NONE;
 994
 995                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
 996                                 step = DIRENT_STEP_FILE;
 997                                 hint_opt->clu = clu.dir;
 998                                 hint_opt->eidx = i;
 999                                 if (type == TYPE_ALL || type == entry_type) {
1000                                         num_ext = ep->dentry.file.num_ext;
1001                                         step = DIRENT_STEP_STRM;
1002                                 }
1003                                 brelse(bh);
1004                                 continue;
1005                         }
1006
1007                         if (entry_type == TYPE_STREAM) {
1008                                 u16 name_hash;
1009
1010                                 if (step != DIRENT_STEP_STRM) {
1011                                         step = DIRENT_STEP_FILE;
1012                                         brelse(bh);
1013                                         continue;
1014                                 }
1015                                 step = DIRENT_STEP_FILE;
1016                                 name_hash = le16_to_cpu(
1017                                                 ep->dentry.stream.name_hash);
1018                                 if (p_uniname->name_hash == name_hash &&
1019                                     p_uniname->name_len ==
1020                                                 ep->dentry.stream.name_len) {
1021                                         step = DIRENT_STEP_NAME;
1022                                         order = 1;
1023                                         name_len = 0;
1024                                 }
1025                                 brelse(bh);
1026                                 continue;
1027                         }
1028
1029                         brelse(bh);
1030                         if (entry_type == TYPE_EXTEND) {
1031                                 unsigned short entry_uniname[16], unichar;
1032
1033                                 if (step != DIRENT_STEP_NAME) {
1034                                         step = DIRENT_STEP_FILE;
1035                                         continue;
1036                                 }
1037
1038                                 if (++order == 2)
1039                                         uniname = p_uniname->name;
1040                                 else
1041                                         uniname += EXFAT_FILE_NAME_LEN;
1042
1043                                 len = exfat_extract_uni_name(ep, entry_uniname);
1044                                 name_len += len;
1045
1046                                 unichar = *(uniname+len);
1047                                 *(uniname+len) = 0x0;
1048
1049                                 if (exfat_uniname_ncmp(sb, uniname,
1050                                         entry_uniname, len)) {
1051                                         step = DIRENT_STEP_FILE;
1052                                 } else if (p_uniname->name_len == name_len) {
1053                                         if (order == num_ext)
1054                                                 goto found;
1055                                         step = DIRENT_STEP_SECD;
1056                                 }
1057
1058                                 *(uniname+len) = unichar;
1059                                 continue;
1060                         }
1061
1062                         if (entry_type &
1063                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1064                                 if (step == DIRENT_STEP_SECD) {
1065                                         if (++order == num_ext)
1066                                                 goto found;
1067                                         continue;
1068                                 }
1069                         }
1070                         step = DIRENT_STEP_FILE;
1071                 }
1072
1073                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1074                         if (--clu.size > 0)
1075                                 clu.dir++;
1076                         else
1077                                 clu.dir = EXFAT_EOF_CLUSTER;
1078                 } else {
1079                         if (exfat_get_next_cluster(sb, &clu.dir))
1080                                 return -EIO;
1081                 }
1082         }
1083
1084 not_found:
1085         /*
1086          * We started at not 0 index,so we should try to find target
1087          * from 0 index to the index we started at.
1088          */
1089         if (!rewind && end_eidx) {
1090                 rewind = 1;
1091                 dentry = 0;
1092                 clu.dir = p_dir->dir;
1093                 /* reset empty hint */
1094                 num_empty = 0;
1095                 candi_empty.eidx = EXFAT_HINT_NONE;
1096                 goto rewind;
1097         }
1098
1099         /* initialized hint_stat */
1100         hint_stat->clu = p_dir->dir;
1101         hint_stat->eidx = 0;
1102         return -ENOENT;
1103
1104 found:
1105         /* next dentry we'll find is out of this cluster */
1106         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1107                 int ret = 0;
1108
1109                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1110                         if (--clu.size > 0)
1111                                 clu.dir++;
1112                         else
1113                                 clu.dir = EXFAT_EOF_CLUSTER;
1114                 } else {
1115                         ret = exfat_get_next_cluster(sb, &clu.dir);
1116                 }
1117
1118                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1119                         /* just initialized hint_stat */
1120                         hint_stat->clu = p_dir->dir;
1121                         hint_stat->eidx = 0;
1122                         return (dentry - num_ext);
1123                 }
1124         }
1125
1126         hint_stat->clu = clu.dir;
1127         hint_stat->eidx = dentry + 1;
1128         return dentry - num_ext;
1129 }
1130
1131 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1132                 int entry, struct exfat_dentry *ep)
1133 {
1134         int i, count = 0;
1135         unsigned int type;
1136         struct exfat_dentry *ext_ep;
1137         struct buffer_head *bh;
1138
1139         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1140                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh);
1141                 if (!ext_ep)
1142                         return -EIO;
1143
1144                 type = exfat_get_entry_type(ext_ep);
1145                 brelse(bh);
1146                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1147                         count++;
1148                 else
1149                         break;
1150         }
1151         return count;
1152 }
1153
1154 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1155 {
1156         int i, count = 0;
1157         int dentries_per_clu;
1158         unsigned int entry_type;
1159         struct exfat_chain clu;
1160         struct exfat_dentry *ep;
1161         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1162         struct buffer_head *bh;
1163
1164         dentries_per_clu = sbi->dentries_per_clu;
1165
1166         exfat_chain_dup(&clu, p_dir);
1167
1168         while (clu.dir != EXFAT_EOF_CLUSTER) {
1169                 for (i = 0; i < dentries_per_clu; i++) {
1170                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1171                         if (!ep)
1172                                 return -EIO;
1173                         entry_type = exfat_get_entry_type(ep);
1174                         brelse(bh);
1175
1176                         if (entry_type == TYPE_UNUSED)
1177                                 return count;
1178                         if (entry_type != TYPE_DIR)
1179                                 continue;
1180                         count++;
1181                 }
1182
1183                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1184                         if (--clu.size > 0)
1185                                 clu.dir++;
1186                         else
1187                                 clu.dir = EXFAT_EOF_CLUSTER;
1188                 } else {
1189                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1190                                 return -EIO;
1191                 }
1192         }
1193
1194         return count;
1195 }