fs/exfat/dir.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/bio.h>
   8 #include <linux/buffer_head.h>
   9
  10 #include "exfat_raw.h"
  11 #include "exfat_fs.h"
  12
  13 static int exfat_extract_uni_name(struct exfat_dentry *ep,
  14                 unsigned short *uniname)
  15 {
  16         int i, len = 0;
  17
  18         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
  19                 *uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
  20                 if (*uniname == 0x0)
  21                         return len;
  22                 uniname++;
  23                 len++;
  24         }
  25
  26         *uniname = 0x0;
  27         return len;
  28
  29 }
  30
  31 static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
  32                 struct exfat_chain *p_dir, int entry, unsigned short *uniname)
  33 {
  34         int i;
  35         struct exfat_entry_set_cache *es;
  36         unsigned int uni_len = 0, len;
  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                 len = exfat_extract_uni_name(ep, uniname);
  56                 uni_len += len;
  57                 if (len != EXFAT_FILE_NAME_LEN || uni_len >= MAX_NAME_LENGTH)
  58                         break;
  59                 uniname += EXFAT_FILE_NAME_LEN;
  60         }
  61
  62         exfat_free_dentry_set(es, false);
  63 }
  64
  65 /* read a directory entry from the opened directory */
  66 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  67 {
  68         int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
  69         unsigned int type, clu_offset, max_dentries;
  70         sector_t sector;
  71         struct exfat_chain dir, clu;
  72         struct exfat_uni_name uni_name;
  73         struct exfat_dentry *ep;
  74         struct super_block *sb = inode->i_sb;
  75         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  76         struct exfat_inode_info *ei = EXFAT_I(inode);
  77         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  78         struct buffer_head *bh;
  79
  80         /* check if the given file ID is opened */
  81         if (ei->type != TYPE_DIR)
  82                 return -EPERM;
  83
  84         if (ei->entry == -1)
  85                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  86         else
  87                 exfat_chain_set(&dir, ei->start_clu,
  88                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  89
  90         dentries_per_clu = sbi->dentries_per_clu;
  91         dentries_per_clu_bits = ilog2(dentries_per_clu);
  92         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  93                                            (u64)sbi->num_clusters << dentries_per_clu_bits);
  94
  95         clu_offset = dentry >> dentries_per_clu_bits;
  96         exfat_chain_dup(&clu, &dir);
  97
  98         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  99                 clu.dir += clu_offset;
 100                 clu.size -= clu_offset;
 101         } else {
 102                 /* hint_information */
 103                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
 104                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
 105                         clu_offset -= ei->hint_bmap.off;
 106                         clu.dir = ei->hint_bmap.clu;
 107                 }
 108
 109                 while (clu_offset > 0 && clu.dir != EXFAT_EOF_CLUSTER) {
 110                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 111                                 return -EIO;
 112
 113                         clu_offset--;
 114                 }
 115         }
 116
 117         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
 118                 i = dentry & (dentries_per_clu - 1);
 119
 120                 for ( ; i < dentries_per_clu; i++, dentry++) {
 121                         ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
 122                         if (!ep)
 123                                 return -EIO;
 124
 125                         type = exfat_get_entry_type(ep);
 126                         if (type == TYPE_UNUSED) {
 127                                 brelse(bh);
 128                                 break;
 129                         }
 130
 131                         if (type != TYPE_FILE && type != TYPE_DIR) {
 132                                 brelse(bh);
 133                                 continue;
 134                         }
 135
 136                         num_ext = ep->dentry.file.num_ext;
 137                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 138                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 139                                         ep->dentry.file.create_tz,
 140                                         ep->dentry.file.create_time,
 141                                         ep->dentry.file.create_date,
 142                                         ep->dentry.file.create_time_cs);
 143                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 144                                         ep->dentry.file.modify_tz,
 145                                         ep->dentry.file.modify_time,
 146                                         ep->dentry.file.modify_date,
 147                                         ep->dentry.file.modify_time_cs);
 148                         exfat_get_entry_time(sbi, &dir_entry->atime,
 149                                         ep->dentry.file.access_tz,
 150                                         ep->dentry.file.access_time,
 151                                         ep->dentry.file.access_date,
 152                                         0);
 153
 154                         *uni_name.name = 0x0;
 155                         exfat_get_uniname_from_ext_entry(sb, &clu, i,
 156                                 uni_name.name);
 157                         exfat_utf16_to_nls(sb, &uni_name,
 158                                 dir_entry->namebuf.lfn,
 159                                 dir_entry->namebuf.lfnbuf_len);
 160                         brelse(bh);
 161
 162                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
 163                         if (!ep)
 164                                 return -EIO;
 165                         dir_entry->size =
 166                                 le64_to_cpu(ep->dentry.stream.valid_size);
 167                         dir_entry->entry = dentry;
 168                         brelse(bh);
 169
 170                         ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
 171                         ei->hint_bmap.clu = clu.dir;
 172
 173                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 174                         return 0;
 175                 }
 176
 177                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 178                         if (--clu.size > 0)
 179                                 clu.dir++;
 180                         else
 181                                 clu.dir = EXFAT_EOF_CLUSTER;
 182                 } else {
 183                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 184                                 return -EIO;
 185                 }
 186         }
 187
 188         dir_entry->namebuf.lfn[0] = '\0';
 189         *cpos = EXFAT_DEN_TO_B(dentry);
 190         return 0;
 191 }
 192
 193 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 194 {
 195         nb->lfn = NULL;
 196         nb->lfnbuf_len = 0;
 197 }
 198
 199 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 200 {
 201         nb->lfn = __getname();
 202         if (!nb->lfn)
 203                 return -ENOMEM;
 204         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 205         return 0;
 206 }
 207
 208 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 209 {
 210         if (!nb->lfn)
 211                 return;
 212
 213         __putname(nb->lfn);
 214         exfat_init_namebuf(nb);
 215 }
 216
 217 /*
 218  * Before calling dir_emit*(), sbi->s_lock should be released
 219  * because page fault can occur in dir_emit*().
 220  */
 221 #define ITER_POS_FILLED_DOTS    (2)
 222 static int exfat_iterate(struct file *filp, struct dir_context *ctx)
 223 {
 224         struct inode *inode = filp->f_path.dentry->d_inode;
 225         struct super_block *sb = inode->i_sb;
 226         struct inode *tmp;
 227         struct exfat_dir_entry de;
 228         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 229         struct exfat_inode_info *ei = EXFAT_I(inode);
 230         unsigned long inum;
 231         loff_t cpos, i_pos;
 232         int err = 0, fake_offset = 0;
 233
 234         exfat_init_namebuf(nb);
 235
 236         cpos = ctx->pos;
 237         if (!dir_emit_dots(filp, ctx))
 238                 goto out;
 239
 240         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 241                 cpos = 0;
 242                 fake_offset = 1;
 243         }
 244
 245         cpos = round_up(cpos, DENTRY_SIZE);
 246
 247         /* name buffer should be allocated before use */
 248         err = exfat_alloc_namebuf(nb);
 249         if (err)
 250                 goto out;
 251 get_new:
 252         mutex_lock(&EXFAT_SB(sb)->s_lock);
 253
 254         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 255                 goto end_of_dir;
 256
 257         err = exfat_readdir(inode, &cpos, &de);
 258         if (err) {
 259                 /*
 260                  * At least we tried to read a sector.
 261                  * Move cpos to next sector position (should be aligned).
 262                  */
 263                 if (err == -EIO) {
 264                         cpos += 1 << (sb->s_blocksize_bits);
 265                         cpos &= ~(sb->s_blocksize - 1);
 266                 }
 267
 268                 err = -EIO;
 269                 goto end_of_dir;
 270         }
 271
 272         if (!nb->lfn[0])
 273                 goto end_of_dir;
 274
 275         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 276         tmp = exfat_iget(sb, i_pos);
 277         if (tmp) {
 278                 inum = tmp->i_ino;
 279                 iput(tmp);
 280         } else {
 281                 inum = iunique(sb, EXFAT_ROOT_INO);
 282         }
 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;
 288         ctx->pos = cpos;
 289         goto get_new;
 290
 291 end_of_dir:
 292         if (!cpos && fake_offset)
 293                 cpos = ITER_POS_FILLED_DOTS;
 294         ctx->pos = cpos;
 295         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 296 out:
 297         /*
 298          * To improve performance, free namebuf after unlock sb_lock.
 299          * If namebuf is not allocated, this function do nothing
 300          */
 301         exfat_free_namebuf(nb);
 302         return err;
 303 }
 304
 305 const struct file_operations exfat_dir_operations = {
 306         .llseek         = generic_file_llseek,
 307         .read           = generic_read_dir,
 308         .iterate        = exfat_iterate,
 309         .fsync          = exfat_file_fsync,
 310 };
 311
 312 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 313 {
 314         int ret;
 315
 316         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 317
 318         ret = exfat_alloc_cluster(inode, 1, clu);
 319         if (ret)
 320                 return ret;
 321
 322         return exfat_zeroed_cluster(inode, clu->dir);
 323 }
 324
 325 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 326 {
 327         int len;
 328
 329         len = p_uniname->name_len;
 330         if (len == 0)
 331                 return -EINVAL;
 332
 333         /* 1 file entry + 1 stream entry + name entries */
 334         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 335 }
 336
 337 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 338 {
 339         if (ep->type == EXFAT_UNUSED)
 340                 return TYPE_UNUSED;
 341         if (IS_EXFAT_DELETED(ep->type))
 342                 return TYPE_DELETED;
 343         if (ep->type == EXFAT_INVAL)
 344                 return TYPE_INVALID;
 345         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 346                 if (ep->type == EXFAT_BITMAP)
 347                         return TYPE_BITMAP;
 348                 if (ep->type == EXFAT_UPCASE)
 349                         return TYPE_UPCASE;
 350                 if (ep->type == EXFAT_VOLUME)
 351                         return TYPE_VOLUME;
 352                 if (ep->type == EXFAT_FILE) {
 353                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 354                                 return TYPE_DIR;
 355                         return TYPE_FILE;
 356                 }
 357                 return TYPE_CRITICAL_PRI;
 358         }
 359         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 360                 if (ep->type == EXFAT_GUID)
 361                         return TYPE_GUID;
 362                 if (ep->type == EXFAT_PADDING)
 363                         return TYPE_PADDING;
 364                 if (ep->type == EXFAT_ACLTAB)
 365                         return TYPE_ACLTAB;
 366                 return TYPE_BENIGN_PRI;
 367         }
 368         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 369                 if (ep->type == EXFAT_STREAM)
 370                         return TYPE_STREAM;
 371                 if (ep->type == EXFAT_NAME)
 372                         return TYPE_EXTEND;
 373                 if (ep->type == EXFAT_ACL)
 374                         return TYPE_ACL;
 375                 return TYPE_CRITICAL_SEC;
 376         }
 377         return TYPE_BENIGN_SEC;
 378 }
 379
 380 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 381 {
 382         if (type == TYPE_UNUSED) {
 383                 ep->type = EXFAT_UNUSED;
 384         } else if (type == TYPE_DELETED) {
 385                 ep->type &= EXFAT_DELETE;
 386         } else if (type == TYPE_STREAM) {
 387                 ep->type = EXFAT_STREAM;
 388         } else if (type == TYPE_EXTEND) {
 389                 ep->type = EXFAT_NAME;
 390         } else if (type == TYPE_BITMAP) {
 391                 ep->type = EXFAT_BITMAP;
 392         } else if (type == TYPE_UPCASE) {
 393                 ep->type = EXFAT_UPCASE;
 394         } else if (type == TYPE_VOLUME) {
 395                 ep->type = EXFAT_VOLUME;
 396         } else if (type == TYPE_DIR) {
 397                 ep->type = EXFAT_FILE;
 398                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 399         } else if (type == TYPE_FILE) {
 400                 ep->type = EXFAT_FILE;
 401                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 402         }
 403 }
 404
 405 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 406                 unsigned char flags, unsigned int start_clu,
 407                 unsigned long long size)
 408 {
 409         exfat_set_entry_type(ep, TYPE_STREAM);
 410         ep->dentry.stream.flags = flags;
 411         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 412         ep->dentry.stream.valid_size = cpu_to_le64(size);
 413         ep->dentry.stream.size = cpu_to_le64(size);
 414 }
 415
 416 static void exfat_init_name_entry(struct exfat_dentry *ep,
 417                 unsigned short *uniname)
 418 {
 419         int i;
 420
 421         exfat_set_entry_type(ep, TYPE_EXTEND);
 422         ep->dentry.name.flags = 0x0;
 423
 424         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 425                 if (*uniname != 0x0) {
 426                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 427                         uniname++;
 428                 } else {
 429                         ep->dentry.name.unicode_0_14[i] = 0x0;
 430                 }
 431         }
 432 }
 433
 434 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 435                 int entry, unsigned int type, unsigned int start_clu,
 436                 unsigned long long size)
 437 {
 438         struct super_block *sb = inode->i_sb;
 439         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 440         struct timespec64 ts = current_time(inode);
 441         sector_t sector;
 442         struct exfat_dentry *ep;
 443         struct buffer_head *bh;
 444
 445         /*
 446          * We cannot use exfat_get_dentry_set here because file ep is not
 447          * initialized yet.
 448          */
 449         ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
 450         if (!ep)
 451                 return -EIO;
 452
 453         exfat_set_entry_type(ep, type);
 454         exfat_set_entry_time(sbi, &ts,
 455                         &ep->dentry.file.create_tz,
 456                         &ep->dentry.file.create_time,
 457                         &ep->dentry.file.create_date,
 458                         &ep->dentry.file.create_time_cs);
 459         exfat_set_entry_time(sbi, &ts,
 460                         &ep->dentry.file.modify_tz,
 461                         &ep->dentry.file.modify_time,
 462                         &ep->dentry.file.modify_date,
 463                         &ep->dentry.file.modify_time_cs);
 464         exfat_set_entry_time(sbi, &ts,
 465                         &ep->dentry.file.access_tz,
 466                         &ep->dentry.file.access_time,
 467                         &ep->dentry.file.access_date,
 468                         NULL);
 469
 470         exfat_update_bh(bh, IS_DIRSYNC(inode));
 471         brelse(bh);
 472
 473         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
 474         if (!ep)
 475                 return -EIO;
 476
 477         exfat_init_stream_entry(ep,
 478                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 479                 start_clu, size);
 480         exfat_update_bh(bh, IS_DIRSYNC(inode));
 481         brelse(bh);
 482
 483         return 0;
 484 }
 485
 486 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 487                 int entry)
 488 {
 489         struct super_block *sb = inode->i_sb;
 490         int ret = 0;
 491         int i, num_entries;
 492         sector_t sector;
 493         u16 chksum;
 494         struct exfat_dentry *ep, *fep;
 495         struct buffer_head *fbh, *bh;
 496
 497         fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
 498         if (!fep)
 499                 return -EIO;
 500
 501         num_entries = fep->dentry.file.num_ext + 1;
 502         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 503
 504         for (i = 1; i < num_entries; i++) {
 505                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
 506                 if (!ep) {
 507                         ret = -EIO;
 508                         goto release_fbh;
 509                 }
 510                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 511                                 CS_DEFAULT);
 512                 brelse(bh);
 513         }
 514
 515         fep->dentry.file.checksum = cpu_to_le16(chksum);
 516         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 517 release_fbh:
 518         brelse(fbh);
 519         return ret;
 520 }
 521
 522 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 523                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 524 {
 525         struct super_block *sb = inode->i_sb;
 526         int i;
 527         sector_t sector;
 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, &sector);
 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, &sector);
 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, &sector);
 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         sector_t sector;
 571         struct exfat_dentry *ep;
 572         struct buffer_head *bh;
 573
 574         for (i = order; i < num_entries; i++) {
 575                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
 576                 if (!ep)
 577                         return -EIO;
 578
 579                 exfat_set_entry_type(ep, TYPE_DELETED);
 580                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 581                 brelse(bh);
 582         }
 583
 584         return 0;
 585 }
 586
 587 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 588 {
 589         int chksum_type = CS_DIR_ENTRY, i;
 590         unsigned short chksum = 0;
 591         struct exfat_dentry *ep;
 592
 593         for (i = 0; i < es->num_entries; i++) {
 594                 ep = exfat_get_dentry_cached(es, i);
 595                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 596                                              chksum_type);
 597                 chksum_type = CS_DEFAULT;
 598         }
 599         ep = exfat_get_dentry_cached(es, 0);
 600         ep->dentry.file.checksum = cpu_to_le16(chksum);
 601         es->modified = true;
 602 }
 603
 604 int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
 605 {
 606         int i, err = 0;
 607
 608         if (es->modified)
 609                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 610
 611         for (i = 0; i < es->num_bh; i++)
 612                 if (err)
 613                         bforget(es->bh[i]);
 614                 else
 615                         brelse(es->bh[i]);
 616
 617         if (IS_DYNAMIC_ES(es))
 618                 kfree(es->bh);
 619
 620         kfree(es);
 621         return err;
 622 }
 623
 624 static int exfat_walk_fat_chain(struct super_block *sb,
 625                 struct exfat_chain *p_dir, unsigned int byte_offset,
 626                 unsigned int *clu)
 627 {
 628         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 629         unsigned int clu_offset;
 630         unsigned int cur_clu;
 631
 632         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 633         cur_clu = p_dir->dir;
 634
 635         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 636                 cur_clu += clu_offset;
 637         } else {
 638                 while (clu_offset > 0) {
 639                         if (exfat_get_next_cluster(sb, &cur_clu))
 640                                 return -EIO;
 641                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 642                                 exfat_fs_error(sb,
 643                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 644                                         p_dir->dir,
 645                                         EXFAT_B_TO_DEN(byte_offset));
 646                                 return -EIO;
 647                         }
 648                         clu_offset--;
 649                 }
 650         }
 651
 652         *clu = cur_clu;
 653         return 0;
 654 }
 655
 656 int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 657                 int entry, sector_t *sector, int *offset)
 658 {
 659         int ret;
 660         unsigned int off, clu = 0;
 661         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 662
 663         off = EXFAT_DEN_TO_B(entry);
 664
 665         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 666         if (ret)
 667                 return ret;
 668
 669         /* byte offset in cluster */
 670         off = EXFAT_CLU_OFFSET(off, sbi);
 671
 672         /* byte offset in sector    */
 673         *offset = EXFAT_BLK_OFFSET(off, sb);
 674
 675         /* sector offset in cluster */
 676         *sector = EXFAT_B_TO_BLK(off, sb);
 677         *sector += exfat_cluster_to_sector(sbi, clu);
 678         return 0;
 679 }
 680
 681 #define EXFAT_MAX_RA_SIZE     (128*1024)
 682 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 683 {
 684         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 685         struct buffer_head *bh;
 686         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 687         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 688         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 689         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 690
 691         /* Read-ahead is not required */
 692         if (sbi->sect_per_clus == 1)
 693                 return 0;
 694
 695         if (sec < sbi->data_start_sector) {
 696                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 697                           (unsigned long long)sec, sbi->data_start_sector);
 698                 return -EIO;
 699         }
 700
 701         /* Not sector aligned with ra_count, resize ra_count to page size */
 702         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 703                 ra_count = page_ra_count;
 704
 705         bh = sb_find_get_block(sb, sec);
 706         if (!bh || !buffer_uptodate(bh)) {
 707                 unsigned int i;
 708
 709                 for (i = 0; i < ra_count; i++)
 710                         sb_breadahead(sb, (sector_t)(sec + i));
 711         }
 712         brelse(bh);
 713         return 0;
 714 }
 715
 716 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 717                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 718                 sector_t *sector)
 719 {
 720         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 721         int off;
 722         sector_t sec;
 723
 724         if (p_dir->dir == DIR_DELETED) {
 725                 exfat_err(sb, "abnormal access to deleted dentry");
 726                 return NULL;
 727         }
 728
 729         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 730                 return NULL;
 731
 732         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 733                         !(entry & (dentries_per_page - 1)))
 734                 exfat_dir_readahead(sb, sec);
 735
 736         *bh = sb_bread(sb, sec);
 737         if (!*bh)
 738                 return NULL;
 739
 740         if (sector)
 741                 *sector = sec;
 742         return (struct exfat_dentry *)((*bh)->b_data + off);
 743 }
 744
 745 enum exfat_validate_dentry_mode {
 746         ES_MODE_STARTED,
 747         ES_MODE_GET_FILE_ENTRY,
 748         ES_MODE_GET_STRM_ENTRY,
 749         ES_MODE_GET_NAME_ENTRY,
 750         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 751 };
 752
 753 static bool exfat_validate_entry(unsigned int type,
 754                 enum exfat_validate_dentry_mode *mode)
 755 {
 756         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 757                 return false;
 758
 759         switch (*mode) {
 760         case ES_MODE_STARTED:
 761                 if  (type != TYPE_FILE && type != TYPE_DIR)
 762                         return false;
 763                 *mode = ES_MODE_GET_FILE_ENTRY;
 764                 return true;
 765         case ES_MODE_GET_FILE_ENTRY:
 766                 if (type != TYPE_STREAM)
 767                         return false;
 768                 *mode = ES_MODE_GET_STRM_ENTRY;
 769                 return true;
 770         case ES_MODE_GET_STRM_ENTRY:
 771                 if (type != TYPE_EXTEND)
 772                         return false;
 773                 *mode = ES_MODE_GET_NAME_ENTRY;
 774                 return true;
 775         case ES_MODE_GET_NAME_ENTRY:
 776                 if (type == TYPE_STREAM)
 777                         return false;
 778                 if (type != TYPE_EXTEND) {
 779                         if (!(type & TYPE_CRITICAL_SEC))
 780                                 return false;
 781                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 782                 }
 783                 return true;
 784         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 785                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 786                         return false;
 787                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 788                         return false;
 789                 return true;
 790         default:
 791                 WARN_ON_ONCE(1);
 792                 return false;
 793         }
 794 }
 795
 796 struct exfat_dentry *exfat_get_dentry_cached(
 797         struct exfat_entry_set_cache *es, int num)
 798 {
 799         int off = es->start_off + num * DENTRY_SIZE;
 800         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 801         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 802
 803         return (struct exfat_dentry *)p;
 804 }
 805
 806 /*
 807  * Returns a set of dentries for a file or dir.
 808  *
 809  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 810  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 811  * changes made in this entry set to the real device.
 812  *
 813  * in:
 814  *   sb+p_dir+entry: indicates a file/dir
 815  *   type:  specifies how many dentries should be included.
 816  * return:
 817  *   pointer of entry set on success,
 818  *   NULL on failure.
 819  */
 820 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 821                 struct exfat_chain *p_dir, int entry, unsigned int type)
 822 {
 823         int ret, i, num_bh;
 824         unsigned int off, byte_offset, clu = 0;
 825         sector_t sec;
 826         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 827         struct exfat_entry_set_cache *es;
 828         struct exfat_dentry *ep;
 829         int num_entries;
 830         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 831         struct buffer_head *bh;
 832
 833         if (p_dir->dir == DIR_DELETED) {
 834                 exfat_err(sb, "access to deleted dentry");
 835                 return NULL;
 836         }
 837
 838         byte_offset = EXFAT_DEN_TO_B(entry);
 839         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
 840         if (ret)
 841                 return NULL;
 842
 843         es = kzalloc(sizeof(*es), GFP_KERNEL);
 844         if (!es)
 845                 return NULL;
 846         es->sb = sb;
 847         es->modified = false;
 848
 849         /* byte offset in cluster */
 850         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 851
 852         /* byte offset in sector */
 853         off = EXFAT_BLK_OFFSET(byte_offset, sb);
 854         es->start_off = off;
 855         es->bh = es->__bh;
 856
 857         /* sector offset in cluster */
 858         sec = EXFAT_B_TO_BLK(byte_offset, sb);
 859         sec += exfat_cluster_to_sector(sbi, clu);
 860
 861         bh = sb_bread(sb, sec);
 862         if (!bh)
 863                 goto free_es;
 864         es->bh[es->num_bh++] = bh;
 865
 866         ep = exfat_get_dentry_cached(es, 0);
 867         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 868                 goto free_es;
 869
 870         num_entries = type == ES_ALL_ENTRIES ?
 871                 ep->dentry.file.num_ext + 1 : type;
 872         es->num_entries = num_entries;
 873
 874         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 875         if (num_bh > ARRAY_SIZE(es->__bh)) {
 876                 es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_KERNEL);
 877                 if (!es->bh) {
 878                         brelse(bh);
 879                         kfree(es);
 880                         return NULL;
 881                 }
 882                 es->bh[0] = bh;
 883         }
 884
 885         for (i = 1; i < num_bh; i++) {
 886                 /* get the next sector */
 887                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 888                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 889                                 clu++;
 890                         else if (exfat_get_next_cluster(sb, &clu))
 891                                 goto free_es;
 892                         sec = exfat_cluster_to_sector(sbi, clu);
 893                 } else {
 894                         sec++;
 895                 }
 896
 897                 bh = sb_bread(sb, sec);
 898                 if (!bh)
 899                         goto free_es;
 900                 es->bh[es->num_bh++] = bh;
 901         }
 902
 903         /* validiate cached dentries */
 904         for (i = 1; i < num_entries; i++) {
 905                 ep = exfat_get_dentry_cached(es, i);
 906                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 907                         goto free_es;
 908         }
 909         return es;
 910
 911 free_es:
 912         exfat_free_dentry_set(es, false);
 913         return NULL;
 914 }
 915
 916 enum {
 917         DIRENT_STEP_FILE,
 918         DIRENT_STEP_STRM,
 919         DIRENT_STEP_NAME,
 920         DIRENT_STEP_SECD,
 921 };
 922
 923 /*
 924  * @ei:         inode info of parent directory
 925  * @p_dir:      directory structure of parent directory
 926  * @num_entries:entry size of p_uniname
 927  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 928  *              for traversing cluster chain.
 929  * @return:
 930  *   >= 0:      file directory entry position where the name exists
 931  *   -ENOENT:   entry with the name does not exist
 932  *   -EIO:      I/O error
 933  */
 934 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 935                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 936                 int num_entries, unsigned int type, struct exfat_hint *hint_opt)
 937 {
 938         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 939         int order, step, name_len = 0;
 940         int dentries_per_clu, num_empty = 0;
 941         unsigned int entry_type;
 942         unsigned short *uniname = NULL;
 943         struct exfat_chain clu;
 944         struct exfat_hint *hint_stat = &ei->hint_stat;
 945         struct exfat_hint_femp candi_empty;
 946         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 947
 948         dentries_per_clu = sbi->dentries_per_clu;
 949
 950         exfat_chain_dup(&clu, p_dir);
 951
 952         if (hint_stat->eidx) {
 953                 clu.dir = hint_stat->clu;
 954                 dentry = hint_stat->eidx;
 955                 end_eidx = dentry;
 956         }
 957
 958         candi_empty.eidx = EXFAT_HINT_NONE;
 959 rewind:
 960         order = 0;
 961         step = DIRENT_STEP_FILE;
 962         while (clu.dir != EXFAT_EOF_CLUSTER) {
 963                 i = dentry & (dentries_per_clu - 1);
 964                 for (; i < dentries_per_clu; i++, dentry++) {
 965                         struct exfat_dentry *ep;
 966                         struct buffer_head *bh;
 967
 968                         if (rewind && dentry == end_eidx)
 969                                 goto not_found;
 970
 971                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
 972                         if (!ep)
 973                                 return -EIO;
 974
 975                         entry_type = exfat_get_entry_type(ep);
 976
 977                         if (entry_type == TYPE_UNUSED ||
 978                             entry_type == TYPE_DELETED) {
 979                                 step = DIRENT_STEP_FILE;
 980
 981                                 num_empty++;
 982                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 983                                                 num_empty == 1) {
 984                                         exfat_chain_set(&candi_empty.cur,
 985                                                 clu.dir, clu.size, clu.flags);
 986                                 }
 987
 988                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 989                                                 num_empty >= num_entries) {
 990                                         candi_empty.eidx =
 991                                                 dentry - (num_empty - 1);
 992                                         WARN_ON(candi_empty.eidx < 0);
 993                                         candi_empty.count = num_empty;
 994
 995                                         if (ei->hint_femp.eidx ==
 996                                                         EXFAT_HINT_NONE ||
 997                                                 candi_empty.eidx <=
 998                                                          ei->hint_femp.eidx)
 999                                                 ei->hint_femp = candi_empty;
1000                                 }
1001
1002                                 brelse(bh);
1003                                 if (entry_type == TYPE_UNUSED)
1004                                         goto not_found;
1005                                 continue;
1006                         }
1007
1008                         num_empty = 0;
1009                         candi_empty.eidx = EXFAT_HINT_NONE;
1010
1011                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1012                                 step = DIRENT_STEP_FILE;
1013                                 hint_opt->clu = clu.dir;
1014                                 hint_opt->eidx = i;
1015                                 if (type == TYPE_ALL || type == entry_type) {
1016                                         num_ext = ep->dentry.file.num_ext;
1017                                         step = DIRENT_STEP_STRM;
1018                                 }
1019                                 brelse(bh);
1020                                 continue;
1021                         }
1022
1023                         if (entry_type == TYPE_STREAM) {
1024                                 u16 name_hash;
1025
1026                                 if (step != DIRENT_STEP_STRM) {
1027                                         step = DIRENT_STEP_FILE;
1028                                         brelse(bh);
1029                                         continue;
1030                                 }
1031                                 step = DIRENT_STEP_FILE;
1032                                 name_hash = le16_to_cpu(
1033                                                 ep->dentry.stream.name_hash);
1034                                 if (p_uniname->name_hash == name_hash &&
1035                                     p_uniname->name_len ==
1036                                                 ep->dentry.stream.name_len) {
1037                                         step = DIRENT_STEP_NAME;
1038                                         order = 1;
1039                                         name_len = 0;
1040                                 }
1041                                 brelse(bh);
1042                                 continue;
1043                         }
1044
1045                         brelse(bh);
1046                         if (entry_type == TYPE_EXTEND) {
1047                                 unsigned short entry_uniname[16], unichar;
1048
1049                                 if (step != DIRENT_STEP_NAME ||
1050                                     name_len >= MAX_NAME_LENGTH) {
1051                                         step = DIRENT_STEP_FILE;
1052                                         continue;
1053                                 }
1054
1055                                 if (++order == 2)
1056                                         uniname = p_uniname->name;
1057                                 else
1058                                         uniname += EXFAT_FILE_NAME_LEN;
1059
1060                                 len = exfat_extract_uni_name(ep, entry_uniname);
1061                                 name_len += len;
1062
1063                                 unichar = *(uniname+len);
1064                                 *(uniname+len) = 0x0;
1065
1066                                 if (exfat_uniname_ncmp(sb, uniname,
1067                                         entry_uniname, len)) {
1068                                         step = DIRENT_STEP_FILE;
1069                                 } else if (p_uniname->name_len == name_len) {
1070                                         if (order == num_ext)
1071                                                 goto found;
1072                                         step = DIRENT_STEP_SECD;
1073                                 }
1074
1075                                 *(uniname+len) = unichar;
1076                                 continue;
1077                         }
1078
1079                         if (entry_type &
1080                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1081                                 if (step == DIRENT_STEP_SECD) {
1082                                         if (++order == num_ext)
1083                                                 goto found;
1084                                         continue;
1085                                 }
1086                         }
1087                         step = DIRENT_STEP_FILE;
1088                 }
1089
1090                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1091                         if (--clu.size > 0)
1092                                 clu.dir++;
1093                         else
1094                                 clu.dir = EXFAT_EOF_CLUSTER;
1095                 } else {
1096                         if (exfat_get_next_cluster(sb, &clu.dir))
1097                                 return -EIO;
1098                 }
1099         }
1100
1101 not_found:
1102         /*
1103          * We started at not 0 index,so we should try to find target
1104          * from 0 index to the index we started at.
1105          */
1106         if (!rewind && end_eidx) {
1107                 rewind = 1;
1108                 dentry = 0;
1109                 clu.dir = p_dir->dir;
1110                 /* reset empty hint */
1111                 num_empty = 0;
1112                 candi_empty.eidx = EXFAT_HINT_NONE;
1113                 goto rewind;
1114         }
1115
1116         /* initialized hint_stat */
1117         hint_stat->clu = p_dir->dir;
1118         hint_stat->eidx = 0;
1119         return -ENOENT;
1120
1121 found:
1122         /* next dentry we'll find is out of this cluster */
1123         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1124                 int ret = 0;
1125
1126                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1127                         if (--clu.size > 0)
1128                                 clu.dir++;
1129                         else
1130                                 clu.dir = EXFAT_EOF_CLUSTER;
1131                 } else {
1132                         ret = exfat_get_next_cluster(sb, &clu.dir);
1133                 }
1134
1135                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1136                         /* just initialized hint_stat */
1137                         hint_stat->clu = p_dir->dir;
1138                         hint_stat->eidx = 0;
1139                         return (dentry - num_ext);
1140                 }
1141         }
1142
1143         hint_stat->clu = clu.dir;
1144         hint_stat->eidx = dentry + 1;
1145         return dentry - num_ext;
1146 }
1147
1148 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1149                 int entry, struct exfat_dentry *ep)
1150 {
1151         int i, count = 0;
1152         unsigned int type;
1153         struct exfat_dentry *ext_ep;
1154         struct buffer_head *bh;
1155
1156         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1157                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
1158                 if (!ext_ep)
1159                         return -EIO;
1160
1161                 type = exfat_get_entry_type(ext_ep);
1162                 brelse(bh);
1163                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1164                         count++;
1165                 else
1166                         break;
1167         }
1168         return count;
1169 }
1170
1171 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1172 {
1173         int i, count = 0;
1174         int dentries_per_clu;
1175         unsigned int entry_type;
1176         struct exfat_chain clu;
1177         struct exfat_dentry *ep;
1178         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1179         struct buffer_head *bh;
1180
1181         dentries_per_clu = sbi->dentries_per_clu;
1182
1183         exfat_chain_dup(&clu, p_dir);
1184
1185         while (clu.dir != EXFAT_EOF_CLUSTER) {
1186                 for (i = 0; i < dentries_per_clu; i++) {
1187                         ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
1188                         if (!ep)
1189                                 return -EIO;
1190                         entry_type = exfat_get_entry_type(ep);
1191                         brelse(bh);
1192
1193                         if (entry_type == TYPE_UNUSED)
1194                                 return count;
1195                         if (entry_type != TYPE_DIR)
1196                                 continue;
1197                         count++;
1198                 }
1199
1200                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1201                         if (--clu.size > 0)
1202                                 clu.dir++;
1203                         else
1204                                 clu.dir = EXFAT_EOF_CLUSTER;
1205                 } else {
1206                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1207                                 return -EIO;
1208                 }
1209         }
1210
1211         return count;
1212 }