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