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         unsigned int uni_len = 0, len;
  38
  39         es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
  40         if (!es)
  41                 return;
  42
  43         /*
  44          * First entry  : file entry
  45          * Second entry : stream-extension entry
  46          * Third entry  : first file-name entry
  47          * So, the index of first file-name dentry should start from 2.
  48          */
  49         for (i = 2; i < es->num_entries; i++) {
  50                 struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
  51
  52                 /* end of name entry */
  53                 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
  54                         break;
  55
  56                 len = exfat_extract_uni_name(ep, uniname);
  57                 uni_len += len;
  58                 if (len != EXFAT_FILE_NAME_LEN || uni_len >= MAX_NAME_LENGTH)
  59                         break;
  60                 uniname += EXFAT_FILE_NAME_LEN;
  61         }
  62
  63         exfat_free_dentry_set(es, false);
  64 }
  65
  66 /* read a directory entry from the opened directory */
  67 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  68 {
  69         int i, dentries_per_clu, dentries_per_clu_bits = 0, num_ext;
  70         unsigned int type, clu_offset, max_dentries;
  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);
 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);
 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 *file, struct dir_context *ctx)
 223 {
 224         struct inode *inode = file_inode(file);
 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(file, 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         .unlocked_ioctl = exfat_ioctl,
 310 #ifdef CONFIG_COMPAT
 311         .compat_ioctl = exfat_compat_ioctl,
 312 #endif
 313         .fsync          = exfat_file_fsync,
 314 };
 315
 316 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 317 {
 318         int ret;
 319
 320         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 321
 322         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 323         if (ret)
 324                 return ret;
 325
 326         return exfat_zeroed_cluster(inode, clu->dir);
 327 }
 328
 329 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 330 {
 331         int len;
 332
 333         len = p_uniname->name_len;
 334         if (len == 0)
 335                 return -EINVAL;
 336
 337         /* 1 file entry + 1 stream entry + name entries */
 338         return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
 339 }
 340
 341 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 342 {
 343         if (ep->type == EXFAT_UNUSED)
 344                 return TYPE_UNUSED;
 345         if (IS_EXFAT_DELETED(ep->type))
 346                 return TYPE_DELETED;
 347         if (ep->type == EXFAT_INVAL)
 348                 return TYPE_INVALID;
 349         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 350                 if (ep->type == EXFAT_BITMAP)
 351                         return TYPE_BITMAP;
 352                 if (ep->type == EXFAT_UPCASE)
 353                         return TYPE_UPCASE;
 354                 if (ep->type == EXFAT_VOLUME)
 355                         return TYPE_VOLUME;
 356                 if (ep->type == EXFAT_FILE) {
 357                         if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
 358                                 return TYPE_DIR;
 359                         return TYPE_FILE;
 360                 }
 361                 return TYPE_CRITICAL_PRI;
 362         }
 363         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 364                 if (ep->type == EXFAT_GUID)
 365                         return TYPE_GUID;
 366                 if (ep->type == EXFAT_PADDING)
 367                         return TYPE_PADDING;
 368                 if (ep->type == EXFAT_ACLTAB)
 369                         return TYPE_ACLTAB;
 370                 return TYPE_BENIGN_PRI;
 371         }
 372         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 373                 if (ep->type == EXFAT_STREAM)
 374                         return TYPE_STREAM;
 375                 if (ep->type == EXFAT_NAME)
 376                         return TYPE_EXTEND;
 377                 if (ep->type == EXFAT_ACL)
 378                         return TYPE_ACL;
 379                 return TYPE_CRITICAL_SEC;
 380         }
 381         return TYPE_BENIGN_SEC;
 382 }
 383
 384 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 385 {
 386         if (type == TYPE_UNUSED) {
 387                 ep->type = EXFAT_UNUSED;
 388         } else if (type == TYPE_DELETED) {
 389                 ep->type &= EXFAT_DELETE;
 390         } else if (type == TYPE_STREAM) {
 391                 ep->type = EXFAT_STREAM;
 392         } else if (type == TYPE_EXTEND) {
 393                 ep->type = EXFAT_NAME;
 394         } else if (type == TYPE_BITMAP) {
 395                 ep->type = EXFAT_BITMAP;
 396         } else if (type == TYPE_UPCASE) {
 397                 ep->type = EXFAT_UPCASE;
 398         } else if (type == TYPE_VOLUME) {
 399                 ep->type = EXFAT_VOLUME;
 400         } else if (type == TYPE_DIR) {
 401                 ep->type = EXFAT_FILE;
 402                 ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
 403         } else if (type == TYPE_FILE) {
 404                 ep->type = EXFAT_FILE;
 405                 ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
 406         }
 407 }
 408
 409 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 410                 unsigned char flags, unsigned int start_clu,
 411                 unsigned long long size)
 412 {
 413         exfat_set_entry_type(ep, TYPE_STREAM);
 414         ep->dentry.stream.flags = flags;
 415         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 416         ep->dentry.stream.valid_size = cpu_to_le64(size);
 417         ep->dentry.stream.size = cpu_to_le64(size);
 418 }
 419
 420 static void exfat_init_name_entry(struct exfat_dentry *ep,
 421                 unsigned short *uniname)
 422 {
 423         int i;
 424
 425         exfat_set_entry_type(ep, TYPE_EXTEND);
 426         ep->dentry.name.flags = 0x0;
 427
 428         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 429                 if (*uniname != 0x0) {
 430                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 431                         uniname++;
 432                 } else {
 433                         ep->dentry.name.unicode_0_14[i] = 0x0;
 434                 }
 435         }
 436 }
 437
 438 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 439                 int entry, unsigned int type, unsigned int start_clu,
 440                 unsigned long long size)
 441 {
 442         struct super_block *sb = inode->i_sb;
 443         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 444         struct timespec64 ts = current_time(inode);
 445         struct exfat_dentry *ep;
 446         struct buffer_head *bh;
 447
 448         /*
 449          * We cannot use exfat_get_dentry_set here because file ep is not
 450          * initialized yet.
 451          */
 452         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
 453         if (!ep)
 454                 return -EIO;
 455
 456         exfat_set_entry_type(ep, type);
 457         exfat_set_entry_time(sbi, &ts,
 458                         &ep->dentry.file.create_tz,
 459                         &ep->dentry.file.create_time,
 460                         &ep->dentry.file.create_date,
 461                         &ep->dentry.file.create_time_cs);
 462         exfat_set_entry_time(sbi, &ts,
 463                         &ep->dentry.file.modify_tz,
 464                         &ep->dentry.file.modify_time,
 465                         &ep->dentry.file.modify_date,
 466                         &ep->dentry.file.modify_time_cs);
 467         exfat_set_entry_time(sbi, &ts,
 468                         &ep->dentry.file.access_tz,
 469                         &ep->dentry.file.access_time,
 470                         &ep->dentry.file.access_date,
 471                         NULL);
 472
 473         exfat_update_bh(bh, IS_DIRSYNC(inode));
 474         brelse(bh);
 475
 476         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
 477         if (!ep)
 478                 return -EIO;
 479
 480         exfat_init_stream_entry(ep,
 481                 (type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
 482                 start_clu, size);
 483         exfat_update_bh(bh, IS_DIRSYNC(inode));
 484         brelse(bh);
 485
 486         return 0;
 487 }
 488
 489 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 490                 int entry)
 491 {
 492         struct super_block *sb = inode->i_sb;
 493         int ret = 0;
 494         int i, num_entries;
 495         u16 chksum;
 496         struct exfat_dentry *ep, *fep;
 497         struct buffer_head *fbh, *bh;
 498
 499         fep = exfat_get_dentry(sb, p_dir, entry, &fbh);
 500         if (!fep)
 501                 return -EIO;
 502
 503         num_entries = fep->dentry.file.num_ext + 1;
 504         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 505
 506         for (i = 1; i < num_entries; i++) {
 507                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 508                 if (!ep) {
 509                         ret = -EIO;
 510                         goto release_fbh;
 511                 }
 512                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 513                                 CS_DEFAULT);
 514                 brelse(bh);
 515         }
 516
 517         fep->dentry.file.checksum = cpu_to_le16(chksum);
 518         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 519 release_fbh:
 520         brelse(fbh);
 521         return ret;
 522 }
 523
 524 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 525                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 526 {
 527         struct super_block *sb = inode->i_sb;
 528         int i;
 529         unsigned short *uniname = p_uniname->name;
 530         struct exfat_dentry *ep;
 531         struct buffer_head *bh;
 532         int sync = IS_DIRSYNC(inode);
 533
 534         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
 535         if (!ep)
 536                 return -EIO;
 537
 538         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 539         exfat_update_bh(bh, sync);
 540         brelse(bh);
 541
 542         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
 543         if (!ep)
 544                 return -EIO;
 545
 546         ep->dentry.stream.name_len = p_uniname->name_len;
 547         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 548         exfat_update_bh(bh, sync);
 549         brelse(bh);
 550
 551         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
 552                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 553                 if (!ep)
 554                         return -EIO;
 555
 556                 exfat_init_name_entry(ep, uniname);
 557                 exfat_update_bh(bh, sync);
 558                 brelse(bh);
 559                 uniname += EXFAT_FILE_NAME_LEN;
 560         }
 561
 562         exfat_update_dir_chksum(inode, p_dir, entry);
 563         return 0;
 564 }
 565
 566 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 567                 int entry, int order, int num_entries)
 568 {
 569         struct super_block *sb = inode->i_sb;
 570         int i;
 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);
 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         kfree(es);
 617         return err;
 618 }
 619
 620 static int exfat_walk_fat_chain(struct super_block *sb,
 621                 struct exfat_chain *p_dir, unsigned int byte_offset,
 622                 unsigned int *clu)
 623 {
 624         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 625         unsigned int clu_offset;
 626         unsigned int cur_clu;
 627
 628         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 629         cur_clu = p_dir->dir;
 630
 631         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 632                 cur_clu += clu_offset;
 633         } else {
 634                 while (clu_offset > 0) {
 635                         if (exfat_get_next_cluster(sb, &cur_clu))
 636                                 return -EIO;
 637                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 638                                 exfat_fs_error(sb,
 639                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 640                                         p_dir->dir,
 641                                         EXFAT_B_TO_DEN(byte_offset));
 642                                 return -EIO;
 643                         }
 644                         clu_offset--;
 645                 }
 646         }
 647
 648         *clu = cur_clu;
 649         return 0;
 650 }
 651
 652 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 653                                int entry, sector_t *sector, int *offset)
 654 {
 655         int ret;
 656         unsigned int off, clu = 0;
 657         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 658
 659         off = EXFAT_DEN_TO_B(entry);
 660
 661         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 662         if (ret)
 663                 return ret;
 664
 665         /* byte offset in cluster */
 666         off = EXFAT_CLU_OFFSET(off, sbi);
 667
 668         /* byte offset in sector    */
 669         *offset = EXFAT_BLK_OFFSET(off, sb);
 670
 671         /* sector offset in cluster */
 672         *sector = EXFAT_B_TO_BLK(off, sb);
 673         *sector += exfat_cluster_to_sector(sbi, clu);
 674         return 0;
 675 }
 676
 677 #define EXFAT_MAX_RA_SIZE     (128*1024)
 678 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 679 {
 680         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 681         struct buffer_head *bh;
 682         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 683         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 684         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 685         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 686
 687         /* Read-ahead is not required */
 688         if (sbi->sect_per_clus == 1)
 689                 return 0;
 690
 691         if (sec < sbi->data_start_sector) {
 692                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 693                           (unsigned long long)sec, sbi->data_start_sector);
 694                 return -EIO;
 695         }
 696
 697         /* Not sector aligned with ra_count, resize ra_count to page size */
 698         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 699                 ra_count = page_ra_count;
 700
 701         bh = sb_find_get_block(sb, sec);
 702         if (!bh || !buffer_uptodate(bh)) {
 703                 unsigned int i;
 704
 705                 for (i = 0; i < ra_count; i++)
 706                         sb_breadahead(sb, (sector_t)(sec + i));
 707         }
 708         brelse(bh);
 709         return 0;
 710 }
 711
 712 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 713                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
 714 {
 715         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 716         int off;
 717         sector_t sec;
 718
 719         if (p_dir->dir == DIR_DELETED) {
 720                 exfat_err(sb, "abnormal access to deleted dentry");
 721                 return NULL;
 722         }
 723
 724         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 725                 return NULL;
 726
 727         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 728                         !(entry & (dentries_per_page - 1)))
 729                 exfat_dir_readahead(sb, sec);
 730
 731         *bh = sb_bread(sb, sec);
 732         if (!*bh)
 733                 return NULL;
 734
 735         return (struct exfat_dentry *)((*bh)->b_data + off);
 736 }
 737
 738 enum exfat_validate_dentry_mode {
 739         ES_MODE_STARTED,
 740         ES_MODE_GET_FILE_ENTRY,
 741         ES_MODE_GET_STRM_ENTRY,
 742         ES_MODE_GET_NAME_ENTRY,
 743         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 744 };
 745
 746 static bool exfat_validate_entry(unsigned int type,
 747                 enum exfat_validate_dentry_mode *mode)
 748 {
 749         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 750                 return false;
 751
 752         switch (*mode) {
 753         case ES_MODE_STARTED:
 754                 if  (type != TYPE_FILE && type != TYPE_DIR)
 755                         return false;
 756                 *mode = ES_MODE_GET_FILE_ENTRY;
 757                 return true;
 758         case ES_MODE_GET_FILE_ENTRY:
 759                 if (type != TYPE_STREAM)
 760                         return false;
 761                 *mode = ES_MODE_GET_STRM_ENTRY;
 762                 return true;
 763         case ES_MODE_GET_STRM_ENTRY:
 764                 if (type != TYPE_EXTEND)
 765                         return false;
 766                 *mode = ES_MODE_GET_NAME_ENTRY;
 767                 return true;
 768         case ES_MODE_GET_NAME_ENTRY:
 769                 if (type == TYPE_STREAM)
 770                         return false;
 771                 if (type != TYPE_EXTEND) {
 772                         if (!(type & TYPE_CRITICAL_SEC))
 773                                 return false;
 774                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 775                 }
 776                 return true;
 777         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 778                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 779                         return false;
 780                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 781                         return false;
 782                 return true;
 783         default:
 784                 WARN_ON_ONCE(1);
 785                 return false;
 786         }
 787 }
 788
 789 struct exfat_dentry *exfat_get_dentry_cached(
 790         struct exfat_entry_set_cache *es, int num)
 791 {
 792         int off = es->start_off + num * DENTRY_SIZE;
 793         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 794         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 795
 796         return (struct exfat_dentry *)p;
 797 }
 798
 799 /*
 800  * Returns a set of dentries for a file or dir.
 801  *
 802  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 803  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 804  * changes made in this entry set to the real device.
 805  *
 806  * in:
 807  *   sb+p_dir+entry: indicates a file/dir
 808  *   type:  specifies how many dentries should be included.
 809  * return:
 810  *   pointer of entry set on success,
 811  *   NULL on failure.
 812  */
 813 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 814                 struct exfat_chain *p_dir, int entry, unsigned int type)
 815 {
 816         int ret, i, num_bh;
 817         unsigned int off, byte_offset, clu = 0;
 818         sector_t sec;
 819         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 820         struct exfat_entry_set_cache *es;
 821         struct exfat_dentry *ep;
 822         int num_entries;
 823         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 824         struct buffer_head *bh;
 825
 826         if (p_dir->dir == DIR_DELETED) {
 827                 exfat_err(sb, "access to deleted dentry");
 828                 return NULL;
 829         }
 830
 831         byte_offset = EXFAT_DEN_TO_B(entry);
 832         ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
 833         if (ret)
 834                 return NULL;
 835
 836         es = kzalloc(sizeof(*es), GFP_KERNEL);
 837         if (!es)
 838                 return NULL;
 839         es->sb = sb;
 840         es->modified = false;
 841
 842         /* byte offset in cluster */
 843         byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 844
 845         /* byte offset in sector */
 846         off = EXFAT_BLK_OFFSET(byte_offset, sb);
 847         es->start_off = off;
 848
 849         /* sector offset in cluster */
 850         sec = EXFAT_B_TO_BLK(byte_offset, sb);
 851         sec += exfat_cluster_to_sector(sbi, clu);
 852
 853         bh = sb_bread(sb, sec);
 854         if (!bh)
 855                 goto free_es;
 856         es->bh[es->num_bh++] = bh;
 857
 858         ep = exfat_get_dentry_cached(es, 0);
 859         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 860                 goto free_es;
 861
 862         num_entries = type == ES_ALL_ENTRIES ?
 863                 ep->dentry.file.num_ext + 1 : type;
 864         es->num_entries = num_entries;
 865
 866         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 867         for (i = 1; i < num_bh; i++) {
 868                 /* get the next sector */
 869                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 870                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 871                                 clu++;
 872                         else if (exfat_get_next_cluster(sb, &clu))
 873                                 goto free_es;
 874                         sec = exfat_cluster_to_sector(sbi, clu);
 875                 } else {
 876                         sec++;
 877                 }
 878
 879                 bh = sb_bread(sb, sec);
 880                 if (!bh)
 881                         goto free_es;
 882                 es->bh[es->num_bh++] = bh;
 883         }
 884
 885         /* validate cached dentries */
 886         for (i = 1; i < num_entries; i++) {
 887                 ep = exfat_get_dentry_cached(es, i);
 888                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 889                         goto free_es;
 890         }
 891         return es;
 892
 893 free_es:
 894         exfat_free_dentry_set(es, false);
 895         return NULL;
 896 }
 897
 898 enum {
 899         DIRENT_STEP_FILE,
 900         DIRENT_STEP_STRM,
 901         DIRENT_STEP_NAME,
 902         DIRENT_STEP_SECD,
 903 };
 904
 905 /*
 906  * @ei:         inode info of parent directory
 907  * @p_dir:      directory structure of parent directory
 908  * @num_entries:entry size of p_uniname
 909  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 910  *              for traversing cluster chain.
 911  * @return:
 912  *   >= 0:      file directory entry position where the name exists
 913  *   -ENOENT:   entry with the name does not exist
 914  *   -EIO:      I/O error
 915  */
 916 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 917                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 918                 int num_entries, unsigned int type, struct exfat_hint *hint_opt)
 919 {
 920         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 921         int order, step, name_len = 0;
 922         int dentries_per_clu, num_empty = 0;
 923         unsigned int entry_type;
 924         unsigned short *uniname = NULL;
 925         struct exfat_chain clu;
 926         struct exfat_hint *hint_stat = &ei->hint_stat;
 927         struct exfat_hint_femp candi_empty;
 928         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 929
 930         dentries_per_clu = sbi->dentries_per_clu;
 931
 932         exfat_chain_dup(&clu, p_dir);
 933
 934         if (hint_stat->eidx) {
 935                 clu.dir = hint_stat->clu;
 936                 dentry = hint_stat->eidx;
 937                 end_eidx = dentry;
 938         }
 939
 940         candi_empty.eidx = EXFAT_HINT_NONE;
 941 rewind:
 942         order = 0;
 943         step = DIRENT_STEP_FILE;
 944         while (clu.dir != EXFAT_EOF_CLUSTER) {
 945                 i = dentry & (dentries_per_clu - 1);
 946                 for (; i < dentries_per_clu; i++, dentry++) {
 947                         struct exfat_dentry *ep;
 948                         struct buffer_head *bh;
 949
 950                         if (rewind && dentry == end_eidx)
 951                                 goto not_found;
 952
 953                         ep = exfat_get_dentry(sb, &clu, i, &bh);
 954                         if (!ep)
 955                                 return -EIO;
 956
 957                         entry_type = exfat_get_entry_type(ep);
 958
 959                         if (entry_type == TYPE_UNUSED ||
 960                             entry_type == TYPE_DELETED) {
 961                                 step = DIRENT_STEP_FILE;
 962
 963                                 num_empty++;
 964                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 965                                                 num_empty == 1) {
 966                                         exfat_chain_set(&candi_empty.cur,
 967                                                 clu.dir, clu.size, clu.flags);
 968                                 }
 969
 970                                 if (candi_empty.eidx == EXFAT_HINT_NONE &&
 971                                                 num_empty >= num_entries) {
 972                                         candi_empty.eidx =
 973                                                 dentry - (num_empty - 1);
 974                                         WARN_ON(candi_empty.eidx < 0);
 975                                         candi_empty.count = num_empty;
 976
 977                                         if (ei->hint_femp.eidx ==
 978                                                         EXFAT_HINT_NONE ||
 979                                                 candi_empty.eidx <=
 980                                                          ei->hint_femp.eidx)
 981                                                 ei->hint_femp = candi_empty;
 982                                 }
 983
 984                                 brelse(bh);
 985                                 if (entry_type == TYPE_UNUSED)
 986                                         goto not_found;
 987                                 continue;
 988                         }
 989
 990                         num_empty = 0;
 991                         candi_empty.eidx = EXFAT_HINT_NONE;
 992
 993                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
 994                                 step = DIRENT_STEP_FILE;
 995                                 hint_opt->clu = clu.dir;
 996                                 hint_opt->eidx = i;
 997                                 if (type == TYPE_ALL || type == entry_type) {
 998                                         num_ext = ep->dentry.file.num_ext;
 999                                         step = DIRENT_STEP_STRM;
1000                                 }
1001                                 brelse(bh);
1002                                 continue;
1003                         }
1004
1005                         if (entry_type == TYPE_STREAM) {
1006                                 u16 name_hash;
1007
1008                                 if (step != DIRENT_STEP_STRM) {
1009                                         step = DIRENT_STEP_FILE;
1010                                         brelse(bh);
1011                                         continue;
1012                                 }
1013                                 step = DIRENT_STEP_FILE;
1014                                 name_hash = le16_to_cpu(
1015                                                 ep->dentry.stream.name_hash);
1016                                 if (p_uniname->name_hash == name_hash &&
1017                                     p_uniname->name_len ==
1018                                                 ep->dentry.stream.name_len) {
1019                                         step = DIRENT_STEP_NAME;
1020                                         order = 1;
1021                                         name_len = 0;
1022                                 }
1023                                 brelse(bh);
1024                                 continue;
1025                         }
1026
1027                         brelse(bh);
1028                         if (entry_type == TYPE_EXTEND) {
1029                                 unsigned short entry_uniname[16], unichar;
1030
1031                                 if (step != DIRENT_STEP_NAME ||
1032                                     name_len >= MAX_NAME_LENGTH) {
1033                                         step = DIRENT_STEP_FILE;
1034                                         continue;
1035                                 }
1036
1037                                 if (++order == 2)
1038                                         uniname = p_uniname->name;
1039                                 else
1040                                         uniname += EXFAT_FILE_NAME_LEN;
1041
1042                                 len = exfat_extract_uni_name(ep, entry_uniname);
1043                                 name_len += len;
1044
1045                                 unichar = *(uniname+len);
1046                                 *(uniname+len) = 0x0;
1047
1048                                 if (exfat_uniname_ncmp(sb, uniname,
1049                                         entry_uniname, len)) {
1050                                         step = DIRENT_STEP_FILE;
1051                                 } else if (p_uniname->name_len == name_len) {
1052                                         if (order == num_ext)
1053                                                 goto found;
1054                                         step = DIRENT_STEP_SECD;
1055                                 }
1056
1057                                 *(uniname+len) = unichar;
1058                                 continue;
1059                         }
1060
1061                         if (entry_type &
1062                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1063                                 if (step == DIRENT_STEP_SECD) {
1064                                         if (++order == num_ext)
1065                                                 goto found;
1066                                         continue;
1067                                 }
1068                         }
1069                         step = DIRENT_STEP_FILE;
1070                 }
1071
1072                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1073                         if (--clu.size > 0)
1074                                 clu.dir++;
1075                         else
1076                                 clu.dir = EXFAT_EOF_CLUSTER;
1077                 } else {
1078                         if (exfat_get_next_cluster(sb, &clu.dir))
1079                                 return -EIO;
1080                 }
1081         }
1082
1083 not_found:
1084         /*
1085          * We started at not 0 index,so we should try to find target
1086          * from 0 index to the index we started at.
1087          */
1088         if (!rewind && end_eidx) {
1089                 rewind = 1;
1090                 dentry = 0;
1091                 clu.dir = p_dir->dir;
1092                 /* reset empty hint */
1093                 num_empty = 0;
1094                 candi_empty.eidx = EXFAT_HINT_NONE;
1095                 goto rewind;
1096         }
1097
1098         /* initialized hint_stat */
1099         hint_stat->clu = p_dir->dir;
1100         hint_stat->eidx = 0;
1101         return -ENOENT;
1102
1103 found:
1104         /* next dentry we'll find is out of this cluster */
1105         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1106                 int ret = 0;
1107
1108                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1109                         if (--clu.size > 0)
1110                                 clu.dir++;
1111                         else
1112                                 clu.dir = EXFAT_EOF_CLUSTER;
1113                 } else {
1114                         ret = exfat_get_next_cluster(sb, &clu.dir);
1115                 }
1116
1117                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1118                         /* just initialized hint_stat */
1119                         hint_stat->clu = p_dir->dir;
1120                         hint_stat->eidx = 0;
1121                         return (dentry - num_ext);
1122                 }
1123         }
1124
1125         hint_stat->clu = clu.dir;
1126         hint_stat->eidx = dentry + 1;
1127         return dentry - num_ext;
1128 }
1129
1130 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1131                 int entry, struct exfat_dentry *ep)
1132 {
1133         int i, count = 0;
1134         unsigned int type;
1135         struct exfat_dentry *ext_ep;
1136         struct buffer_head *bh;
1137
1138         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1139                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh);
1140                 if (!ext_ep)
1141                         return -EIO;
1142
1143                 type = exfat_get_entry_type(ext_ep);
1144                 brelse(bh);
1145                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1146                         count++;
1147                 else
1148                         break;
1149         }
1150         return count;
1151 }
1152
1153 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1154 {
1155         int i, count = 0;
1156         int dentries_per_clu;
1157         unsigned int entry_type;
1158         struct exfat_chain clu;
1159         struct exfat_dentry *ep;
1160         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1161         struct buffer_head *bh;
1162
1163         dentries_per_clu = sbi->dentries_per_clu;
1164
1165         exfat_chain_dup(&clu, p_dir);
1166
1167         while (clu.dir != EXFAT_EOF_CLUSTER) {
1168                 for (i = 0; i < dentries_per_clu; i++) {
1169                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1170                         if (!ep)
1171                                 return -EIO;
1172                         entry_type = exfat_get_entry_type(ep);
1173                         brelse(bh);
1174
1175                         if (entry_type == TYPE_UNUSED)
1176                                 return count;
1177                         if (entry_type != TYPE_DIR)
1178                                 continue;
1179                         count++;
1180                 }
1181
1182                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1183                         if (--clu.size > 0)
1184                                 clu.dir++;
1185                         else
1186                                 clu.dir = EXFAT_EOF_CLUSTER;
1187                 } else {
1188                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1189                                 return -EIO;
1190                 }
1191         }
1192
1193         return count;
1194 }