fs/exfat/dir.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/compat.h>
   8 #include <linux/bio.h>
   9 #include <linux/buffer_head.h>
  10
  11 #include "exfat_raw.h"
  12 #include "exfat_fs.h"
  13
  14 static int exfat_extract_uni_name(struct exfat_dentry *ep,
  15                 unsigned short *uniname)
  16 {
  17         int i, len = 0;
  18
  19         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
  20                 *uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
  21                 if (*uniname == 0x0)
  22                         return len;
  23                 uniname++;
  24                 len++;
  25         }
  26
  27         *uniname = 0x0;
  28         return len;
  29
  30 }
  31
  32 static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
  33                 struct exfat_chain *p_dir, int entry, unsigned short *uniname)
  34 {
  35         int i;
  36         struct exfat_entry_set_cache es;
  37
  38         if (exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES))
  39                 return;
  40
  41         /*
  42          * First entry  : file entry
  43          * Second entry : stream-extension entry
  44          * Third entry  : first file-name entry
  45          * So, the index of first file-name dentry should start from 2.
  46          */
  47         for (i = ES_IDX_FIRST_FILENAME; i < es.num_entries; i++) {
  48                 struct exfat_dentry *ep = exfat_get_dentry_cached(&es, i);
  49
  50                 /* end of name entry */
  51                 if (exfat_get_entry_type(ep) != TYPE_EXTEND)
  52                         break;
  53
  54                 exfat_extract_uni_name(ep, uniname);
  55                 uniname += EXFAT_FILE_NAME_LEN;
  56         }
  57
  58         exfat_put_dentry_set(&es, false);
  59 }
  60
  61 /* read a directory entry from the opened directory */
  62 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  63 {
  64         int i, dentries_per_clu, num_ext;
  65         unsigned int type, clu_offset, max_dentries;
  66         struct exfat_chain dir, clu;
  67         struct exfat_uni_name uni_name;
  68         struct exfat_dentry *ep;
  69         struct super_block *sb = inode->i_sb;
  70         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  71         struct exfat_inode_info *ei = EXFAT_I(inode);
  72         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  73         struct buffer_head *bh;
  74
  75         /* check if the given file ID is opened */
  76         if (ei->type != TYPE_DIR)
  77                 return -EPERM;
  78
  79         if (ei->entry == -1)
  80                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  81         else
  82                 exfat_chain_set(&dir, ei->start_clu,
  83                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  84
  85         dentries_per_clu = sbi->dentries_per_clu;
  86         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  87                                 (u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));
  88
  89         clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
  90         exfat_chain_dup(&clu, &dir);
  91
  92         if (clu.flags == ALLOC_NO_FAT_CHAIN) {
  93                 clu.dir += clu_offset;
  94                 clu.size -= clu_offset;
  95         } else {
  96                 /* hint_information */
  97                 if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
  98                     ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
  99                         clu_offset -= ei->hint_bmap.off;
 100                         clu.dir = ei->hint_bmap.clu;
 101                 }
 102
 103                 while (clu_offset > 0) {
 104                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 105                                 return -EIO;
 106
 107                         clu_offset--;
 108                 }
 109         }
 110
 111         while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
 112                 i = dentry & (dentries_per_clu - 1);
 113
 114                 for ( ; i < dentries_per_clu; i++, dentry++) {
 115                         ep = exfat_get_dentry(sb, &clu, i, &bh);
 116                         if (!ep)
 117                                 return -EIO;
 118
 119                         type = exfat_get_entry_type(ep);
 120                         if (type == TYPE_UNUSED) {
 121                                 brelse(bh);
 122                                 break;
 123                         }
 124
 125                         if (type != TYPE_FILE && type != TYPE_DIR) {
 126                                 brelse(bh);
 127                                 continue;
 128                         }
 129
 130                         num_ext = ep->dentry.file.num_ext;
 131                         dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
 132                         exfat_get_entry_time(sbi, &dir_entry->crtime,
 133                                         ep->dentry.file.create_tz,
 134                                         ep->dentry.file.create_time,
 135                                         ep->dentry.file.create_date,
 136                                         ep->dentry.file.create_time_cs);
 137                         exfat_get_entry_time(sbi, &dir_entry->mtime,
 138                                         ep->dentry.file.modify_tz,
 139                                         ep->dentry.file.modify_time,
 140                                         ep->dentry.file.modify_date,
 141                                         ep->dentry.file.modify_time_cs);
 142                         exfat_get_entry_time(sbi, &dir_entry->atime,
 143                                         ep->dentry.file.access_tz,
 144                                         ep->dentry.file.access_time,
 145                                         ep->dentry.file.access_date,
 146                                         0);
 147
 148                         *uni_name.name = 0x0;
 149                         exfat_get_uniname_from_ext_entry(sb, &clu, i,
 150                                 uni_name.name);
 151                         exfat_utf16_to_nls(sb, &uni_name,
 152                                 dir_entry->namebuf.lfn,
 153                                 dir_entry->namebuf.lfnbuf_len);
 154                         brelse(bh);
 155
 156                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh);
 157                         if (!ep)
 158                                 return -EIO;
 159                         dir_entry->size =
 160                                 le64_to_cpu(ep->dentry.stream.valid_size);
 161                         dir_entry->entry = dentry;
 162                         brelse(bh);
 163
 164                         ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
 165                         ei->hint_bmap.clu = clu.dir;
 166
 167                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 168                         return 0;
 169                 }
 170
 171                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 172                         if (--clu.size > 0)
 173                                 clu.dir++;
 174                         else
 175                                 clu.dir = EXFAT_EOF_CLUSTER;
 176                 } else {
 177                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 178                                 return -EIO;
 179                 }
 180         }
 181
 182         dir_entry->namebuf.lfn[0] = '\0';
 183         *cpos = EXFAT_DEN_TO_B(dentry);
 184         return 0;
 185 }
 186
 187 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 188 {
 189         nb->lfn = NULL;
 190         nb->lfnbuf_len = 0;
 191 }
 192
 193 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 194 {
 195         nb->lfn = __getname();
 196         if (!nb->lfn)
 197                 return -ENOMEM;
 198         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 199         return 0;
 200 }
 201
 202 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 203 {
 204         if (!nb->lfn)
 205                 return;
 206
 207         __putname(nb->lfn);
 208         exfat_init_namebuf(nb);
 209 }
 210
 211 /* skip iterating emit_dots when dir is empty */
 212 #define ITER_POS_FILLED_DOTS    (2)
 213 static int exfat_iterate(struct file *file, struct dir_context *ctx)
 214 {
 215         struct inode *inode = file_inode(file);
 216         struct super_block *sb = inode->i_sb;
 217         struct inode *tmp;
 218         struct exfat_dir_entry de;
 219         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 220         struct exfat_inode_info *ei = EXFAT_I(inode);
 221         unsigned long inum;
 222         loff_t cpos, i_pos;
 223         int err = 0, fake_offset = 0;
 224
 225         exfat_init_namebuf(nb);
 226         mutex_lock(&EXFAT_SB(sb)->s_lock);
 227
 228         cpos = ctx->pos;
 229         if (!dir_emit_dots(file, ctx))
 230                 goto unlock;
 231
 232         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 233                 cpos = 0;
 234                 fake_offset = 1;
 235         }
 236
 237         if (cpos & (DENTRY_SIZE - 1)) {
 238                 err = -ENOENT;
 239                 goto unlock;
 240         }
 241
 242         /* name buffer should be allocated before use */
 243         err = exfat_alloc_namebuf(nb);
 244         if (err)
 245                 goto unlock;
 246 get_new:
 247         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 248                 goto end_of_dir;
 249
 250         err = exfat_readdir(inode, &cpos, &de);
 251         if (err) {
 252                 /*
 253                  * At least we tried to read a sector.  Move cpos to next sector
 254                  * position (should be aligned).
 255                  */
 256                 if (err == -EIO) {
 257                         cpos += 1 << (sb->s_blocksize_bits);
 258                         cpos &= ~(sb->s_blocksize - 1);
 259                 }
 260
 261                 err = -EIO;
 262                 goto end_of_dir;
 263         }
 264
 265         if (!nb->lfn[0])
 266                 goto end_of_dir;
 267
 268         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 269         tmp = exfat_iget(sb, i_pos);
 270         if (tmp) {
 271                 inum = tmp->i_ino;
 272                 iput(tmp);
 273         } else {
 274                 inum = iunique(sb, EXFAT_ROOT_INO);
 275         }
 276
 277         /*
 278          * Before calling dir_emit(), sb_lock should be released.
 279          * Because page fault can occur in dir_emit() when the size
 280          * of buffer given from user is larger than one page size.
 281          */
 282         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 283         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 284                         (de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
 285                 goto out_unlocked;
 286         mutex_lock(&EXFAT_SB(sb)->s_lock);
 287         ctx->pos = cpos;
 288         goto get_new;
 289
 290 end_of_dir:
 291         if (!cpos && fake_offset)
 292                 cpos = ITER_POS_FILLED_DOTS;
 293         ctx->pos = cpos;
 294 unlock:
 295         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 296 out_unlocked:
 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 ES_ENTRY_NUM(len);
 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 = ES_IDX_FILE; 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, ES_IDX_FILE);
 600         ep->dentry.file.checksum = cpu_to_le16(chksum);
 601         es->modified = true;
 602 }
 603
 604 int exfat_put_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         return err;
 621 }
 622
 623 static int exfat_walk_fat_chain(struct super_block *sb,
 624                 struct exfat_chain *p_dir, unsigned int byte_offset,
 625                 unsigned int *clu)
 626 {
 627         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 628         unsigned int clu_offset;
 629         unsigned int cur_clu;
 630
 631         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 632         cur_clu = p_dir->dir;
 633
 634         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 635                 cur_clu += clu_offset;
 636         } else {
 637                 while (clu_offset > 0) {
 638                         if (exfat_get_next_cluster(sb, &cur_clu))
 639                                 return -EIO;
 640                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 641                                 exfat_fs_error(sb,
 642                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 643                                         p_dir->dir,
 644                                         EXFAT_B_TO_DEN(byte_offset));
 645                                 return -EIO;
 646                         }
 647                         clu_offset--;
 648                 }
 649         }
 650
 651         *clu = cur_clu;
 652         return 0;
 653 }
 654
 655 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 656                                int entry, sector_t *sector, int *offset)
 657 {
 658         int ret;
 659         unsigned int off, clu = 0;
 660         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 661
 662         off = EXFAT_DEN_TO_B(entry);
 663
 664         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 665         if (ret)
 666                 return ret;
 667
 668         /* byte offset in cluster */
 669         off = EXFAT_CLU_OFFSET(off, sbi);
 670
 671         /* byte offset in sector    */
 672         *offset = EXFAT_BLK_OFFSET(off, sb);
 673
 674         /* sector offset in cluster */
 675         *sector = EXFAT_B_TO_BLK(off, sb);
 676         *sector += exfat_cluster_to_sector(sbi, clu);
 677         return 0;
 678 }
 679
 680 #define EXFAT_MAX_RA_SIZE     (128*1024)
 681 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 682 {
 683         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 684         struct buffer_head *bh;
 685         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 686         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 687         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 688         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 689
 690         /* Read-ahead is not required */
 691         if (sbi->sect_per_clus == 1)
 692                 return 0;
 693
 694         if (sec < sbi->data_start_sector) {
 695                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 696                           (unsigned long long)sec, sbi->data_start_sector);
 697                 return -EIO;
 698         }
 699
 700         /* Not sector aligned with ra_count, resize ra_count to page size */
 701         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 702                 ra_count = page_ra_count;
 703
 704         bh = sb_find_get_block(sb, sec);
 705         if (!bh || !buffer_uptodate(bh)) {
 706                 unsigned int i;
 707
 708                 for (i = 0; i < ra_count; i++)
 709                         sb_breadahead(sb, (sector_t)(sec + i));
 710         }
 711         brelse(bh);
 712         return 0;
 713 }
 714
 715 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 716                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
 717 {
 718         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 719         int off;
 720         sector_t sec;
 721
 722         if (p_dir->dir == DIR_DELETED) {
 723                 exfat_err(sb, "abnormal access to deleted dentry");
 724                 return NULL;
 725         }
 726
 727         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 728                 return NULL;
 729
 730         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 731                         !(entry & (dentries_per_page - 1)))
 732                 exfat_dir_readahead(sb, sec);
 733
 734         *bh = sb_bread(sb, sec);
 735         if (!*bh)
 736                 return NULL;
 737
 738         return (struct exfat_dentry *)((*bh)->b_data + off);
 739 }
 740
 741 enum exfat_validate_dentry_mode {
 742         ES_MODE_STARTED,
 743         ES_MODE_GET_FILE_ENTRY,
 744         ES_MODE_GET_STRM_ENTRY,
 745         ES_MODE_GET_NAME_ENTRY,
 746         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 747 };
 748
 749 static bool exfat_validate_entry(unsigned int type,
 750                 enum exfat_validate_dentry_mode *mode)
 751 {
 752         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 753                 return false;
 754
 755         switch (*mode) {
 756         case ES_MODE_STARTED:
 757                 if  (type != TYPE_FILE && type != TYPE_DIR)
 758                         return false;
 759                 *mode = ES_MODE_GET_FILE_ENTRY;
 760                 return true;
 761         case ES_MODE_GET_FILE_ENTRY:
 762                 if (type != TYPE_STREAM)
 763                         return false;
 764                 *mode = ES_MODE_GET_STRM_ENTRY;
 765                 return true;
 766         case ES_MODE_GET_STRM_ENTRY:
 767                 if (type != TYPE_EXTEND)
 768                         return false;
 769                 *mode = ES_MODE_GET_NAME_ENTRY;
 770                 return true;
 771         case ES_MODE_GET_NAME_ENTRY:
 772                 if (type == TYPE_STREAM)
 773                         return false;
 774                 if (type != TYPE_EXTEND) {
 775                         if (!(type & TYPE_CRITICAL_SEC))
 776                                 return false;
 777                         *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
 778                 }
 779                 return true;
 780         case ES_MODE_GET_CRITICAL_SEC_ENTRY:
 781                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
 782                         return false;
 783                 if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
 784                         return false;
 785                 return true;
 786         default:
 787                 WARN_ON_ONCE(1);
 788                 return false;
 789         }
 790 }
 791
 792 struct exfat_dentry *exfat_get_dentry_cached(
 793         struct exfat_entry_set_cache *es, int num)
 794 {
 795         int off = es->start_off + num * DENTRY_SIZE;
 796         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 797         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 798
 799         return (struct exfat_dentry *)p;
 800 }
 801
 802 /*
 803  * Returns a set of dentries for a file or dir.
 804  *
 805  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 806  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 807  * changes made in this entry set to the real device.
 808  *
 809  * in:
 810  *   sb+p_dir+entry: indicates a file/dir
 811  *   type:  specifies how many dentries should be included.
 812  * return:
 813  *   pointer of entry set on success,
 814  *   NULL on failure.
 815  */
 816 int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
 817                 struct super_block *sb, struct exfat_chain *p_dir, int entry,
 818                 unsigned int type)
 819 {
 820         int ret, i, num_bh;
 821         unsigned int off;
 822         sector_t sec;
 823         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 824         struct exfat_dentry *ep;
 825         int num_entries;
 826         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 827         struct buffer_head *bh;
 828
 829         if (p_dir->dir == DIR_DELETED) {
 830                 exfat_err(sb, "access to deleted dentry");
 831                 return -EIO;
 832         }
 833
 834         ret = exfat_find_location(sb, p_dir, entry, &sec, &off);
 835         if (ret)
 836                 return ret;
 837
 838         memset(es, 0, sizeof(*es));
 839         es->sb = sb;
 840         es->modified = false;
 841         es->start_off = off;
 842         es->bh = es->__bh;
 843
 844         bh = sb_bread(sb, sec);
 845         if (!bh)
 846                 return -EIO;
 847         es->bh[es->num_bh++] = bh;
 848
 849         ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 850         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 851                 goto put_es;
 852
 853         num_entries = type == ES_ALL_ENTRIES ?
 854                 ep->dentry.file.num_ext + 1 : type;
 855         es->num_entries = num_entries;
 856
 857         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 858         if (num_bh > ARRAY_SIZE(es->__bh)) {
 859                 es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_KERNEL);
 860                 if (!es->bh) {
 861                         brelse(bh);
 862                         return -ENOMEM;
 863                 }
 864                 es->bh[0] = bh;
 865         }
 866
 867         for (i = 1; i < num_bh; i++) {
 868                 /* get the next sector */
 869                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 870                         unsigned int clu = exfat_sector_to_cluster(sbi, sec);
 871
 872                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 873                                 clu++;
 874                         else if (exfat_get_next_cluster(sb, &clu))
 875                                 goto put_es;
 876                         sec = exfat_cluster_to_sector(sbi, clu);
 877                 } else {
 878                         sec++;
 879                 }
 880
 881                 bh = sb_bread(sb, sec);
 882                 if (!bh)
 883                         goto put_es;
 884                 es->bh[es->num_bh++] = bh;
 885         }
 886
 887         /* validate cached dentries */
 888         for (i = ES_IDX_STREAM; i < num_entries; i++) {
 889                 ep = exfat_get_dentry_cached(es, i);
 890                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 891                         goto put_es;
 892         }
 893         return 0;
 894
 895 put_es:
 896         exfat_put_dentry_set(es, false);
 897         return -EIO;
 898 }
 899
 900 static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp)
 901 {
 902         hint_femp->eidx = EXFAT_HINT_NONE;
 903         hint_femp->count = 0;
 904 }
 905
 906 static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
 907                 struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
 908                 int dentry, int num_entries, int entry_type)
 909 {
 910         if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
 911             ei->hint_femp.eidx > dentry) {
 912                 int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode));
 913
 914                 if (candi_empty->count == 0) {
 915                         candi_empty->cur = *clu;
 916                         candi_empty->eidx = dentry;
 917                 }
 918
 919                 if (entry_type == TYPE_UNUSED)
 920                         candi_empty->count += total_entries - dentry;
 921                 else
 922                         candi_empty->count++;
 923
 924                 if (candi_empty->count == num_entries ||
 925                     candi_empty->count + candi_empty->eidx == total_entries)
 926                         ei->hint_femp = *candi_empty;
 927         }
 928 }
 929
 930 enum {
 931         DIRENT_STEP_FILE,
 932         DIRENT_STEP_STRM,
 933         DIRENT_STEP_NAME,
 934         DIRENT_STEP_SECD,
 935 };
 936
 937 /*
 938  * @ei:         inode info of parent directory
 939  * @p_dir:      directory structure of parent directory
 940  * @num_entries:entry size of p_uniname
 941  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 942  *              for traversing cluster chain.
 943  * @return:
 944  *   >= 0:      file directory entry position where the name exists
 945  *   -ENOENT:   entry with the name does not exist
 946  *   -EIO:      I/O error
 947  */
 948 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 949                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 950                 struct exfat_hint *hint_opt)
 951 {
 952         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 953         int order, step, name_len = 0;
 954         int dentries_per_clu;
 955         unsigned int entry_type;
 956         unsigned short *uniname = NULL;
 957         struct exfat_chain clu;
 958         struct exfat_hint *hint_stat = &ei->hint_stat;
 959         struct exfat_hint_femp candi_empty;
 960         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 961         int num_entries = exfat_calc_num_entries(p_uniname);
 962
 963         if (num_entries < 0)
 964                 return num_entries;
 965
 966         dentries_per_clu = sbi->dentries_per_clu;
 967
 968         exfat_chain_dup(&clu, p_dir);
 969
 970         if (hint_stat->eidx) {
 971                 clu.dir = hint_stat->clu;
 972                 dentry = hint_stat->eidx;
 973                 end_eidx = dentry;
 974         }
 975
 976         exfat_reset_empty_hint(&ei->hint_femp);
 977
 978 rewind:
 979         order = 0;
 980         step = DIRENT_STEP_FILE;
 981         exfat_reset_empty_hint(&candi_empty);
 982
 983         while (clu.dir != EXFAT_EOF_CLUSTER) {
 984                 i = dentry & (dentries_per_clu - 1);
 985                 for (; i < dentries_per_clu; i++, dentry++) {
 986                         struct exfat_dentry *ep;
 987                         struct buffer_head *bh;
 988
 989                         if (rewind && dentry == end_eidx)
 990                                 goto not_found;
 991
 992                         ep = exfat_get_dentry(sb, &clu, i, &bh);
 993                         if (!ep)
 994                                 return -EIO;
 995
 996                         entry_type = exfat_get_entry_type(ep);
 997
 998                         if (entry_type == TYPE_UNUSED ||
 999                             entry_type == TYPE_DELETED) {
1000                                 step = DIRENT_STEP_FILE;
1001
1002                                 exfat_set_empty_hint(ei, &candi_empty, &clu,
1003                                                 dentry, num_entries,
1004                                                 entry_type);
1005
1006                                 brelse(bh);
1007                                 if (entry_type == TYPE_UNUSED)
1008                                         goto not_found;
1009                                 continue;
1010                         }
1011
1012                         exfat_reset_empty_hint(&candi_empty);
1013
1014                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1015                                 step = DIRENT_STEP_FILE;
1016                                 hint_opt->clu = clu.dir;
1017                                 hint_opt->eidx = i;
1018                                 num_ext = ep->dentry.file.num_ext;
1019                                 step = DIRENT_STEP_STRM;
1020                                 brelse(bh);
1021                                 continue;
1022                         }
1023
1024                         if (entry_type == TYPE_STREAM) {
1025                                 u16 name_hash;
1026
1027                                 if (step != DIRENT_STEP_STRM) {
1028                                         step = DIRENT_STEP_FILE;
1029                                         brelse(bh);
1030                                         continue;
1031                                 }
1032                                 step = DIRENT_STEP_FILE;
1033                                 name_hash = le16_to_cpu(
1034                                                 ep->dentry.stream.name_hash);
1035                                 if (p_uniname->name_hash == name_hash &&
1036                                     p_uniname->name_len ==
1037                                                 ep->dentry.stream.name_len) {
1038                                         step = DIRENT_STEP_NAME;
1039                                         order = 1;
1040                                         name_len = 0;
1041                                 }
1042                                 brelse(bh);
1043                                 continue;
1044                         }
1045
1046                         brelse(bh);
1047                         if (entry_type == TYPE_EXTEND) {
1048                                 unsigned short entry_uniname[16], unichar;
1049
1050                                 if (step != DIRENT_STEP_NAME) {
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                 goto rewind;
1111         }
1112
1113         /*
1114          * set the EXFAT_EOF_CLUSTER flag to avoid search
1115          * from the beginning again when allocated a new cluster
1116          */
1117         if (ei->hint_femp.eidx == EXFAT_HINT_NONE) {
1118                 ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
1119                 ei->hint_femp.eidx = p_dir->size * dentries_per_clu;
1120                 ei->hint_femp.count = 0;
1121         }
1122
1123         /* initialized hint_stat */
1124         hint_stat->clu = p_dir->dir;
1125         hint_stat->eidx = 0;
1126         return -ENOENT;
1127
1128 found:
1129         /* next dentry we'll find is out of this cluster */
1130         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1131                 int ret = 0;
1132
1133                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1134                         if (--clu.size > 0)
1135                                 clu.dir++;
1136                         else
1137                                 clu.dir = EXFAT_EOF_CLUSTER;
1138                 } else {
1139                         ret = exfat_get_next_cluster(sb, &clu.dir);
1140                 }
1141
1142                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1143                         /* just initialized hint_stat */
1144                         hint_stat->clu = p_dir->dir;
1145                         hint_stat->eidx = 0;
1146                         return (dentry - num_ext);
1147                 }
1148         }
1149
1150         hint_stat->clu = clu.dir;
1151         hint_stat->eidx = dentry + 1;
1152         return dentry - num_ext;
1153 }
1154
1155 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1156                 int entry, struct exfat_dentry *ep)
1157 {
1158         int i, count = 0;
1159         unsigned int type;
1160         struct exfat_dentry *ext_ep;
1161         struct buffer_head *bh;
1162
1163         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1164                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh);
1165                 if (!ext_ep)
1166                         return -EIO;
1167
1168                 type = exfat_get_entry_type(ext_ep);
1169                 brelse(bh);
1170                 if (type == TYPE_EXTEND || type == TYPE_STREAM)
1171                         count++;
1172                 else
1173                         break;
1174         }
1175         return count;
1176 }
1177
1178 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1179 {
1180         int i, count = 0;
1181         int dentries_per_clu;
1182         unsigned int entry_type;
1183         struct exfat_chain clu;
1184         struct exfat_dentry *ep;
1185         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1186         struct buffer_head *bh;
1187
1188         dentries_per_clu = sbi->dentries_per_clu;
1189
1190         exfat_chain_dup(&clu, p_dir);
1191
1192         while (clu.dir != EXFAT_EOF_CLUSTER) {
1193                 for (i = 0; i < dentries_per_clu; i++) {
1194                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1195                         if (!ep)
1196                                 return -EIO;
1197                         entry_type = exfat_get_entry_type(ep);
1198                         brelse(bh);
1199
1200                         if (entry_type == TYPE_UNUSED)
1201                                 return count;
1202                         if (entry_type != TYPE_DIR)
1203                                 continue;
1204                         count++;
1205                 }
1206
1207                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1208                         if (--clu.size > 0)
1209                                 clu.dir++;
1210                         else
1211                                 clu.dir = EXFAT_EOF_CLUSTER;
1212                 } else {
1213                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1214                                 return -EIO;
1215                 }
1216         }
1217
1218         return count;
1219 }