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 int 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, err;
  36         struct exfat_entry_set_cache es;
  37         unsigned int uni_len = 0, len;
  38
  39         err = exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES);
  40         if (err)
  41                 return err;
  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 = ES_IDX_FIRST_FILENAME; 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_put_dentry_set(&es, false);
  64         return 0;
  65 }
  66
  67 /* read a directory entry from the opened directory */
  68 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
  69 {
  70         int i, dentries_per_clu, num_ext, err;
  71         unsigned int type, clu_offset, max_dentries;
  72         struct exfat_chain dir, clu;
  73         struct exfat_uni_name uni_name;
  74         struct exfat_dentry *ep;
  75         struct super_block *sb = inode->i_sb;
  76         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  77         struct exfat_inode_info *ei = EXFAT_I(inode);
  78         unsigned int dentry = EXFAT_B_TO_DEN(*cpos) & 0xFFFFFFFF;
  79         struct buffer_head *bh;
  80
  81         /* check if the given file ID is opened */
  82         if (ei->type != TYPE_DIR)
  83                 return -EPERM;
  84
  85         if (ei->entry == -1)
  86                 exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
  87         else
  88                 exfat_chain_set(&dir, ei->start_clu,
  89                         EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
  90
  91         dentries_per_clu = sbi->dentries_per_clu;
  92         max_dentries = (unsigned int)min_t(u64, MAX_EXFAT_DENTRIES,
  93                                 (u64)EXFAT_CLU_TO_DEN(sbi->num_clusters, sbi));
  94
  95         clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
  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                         err = exfat_get_uniname_from_ext_entry(sb, &clu, i,
 156                                 uni_name.name);
 157                         if (err) {
 158                                 brelse(bh);
 159                                 continue;
 160                         }
 161                         exfat_utf16_to_nls(sb, &uni_name,
 162                                 dir_entry->namebuf.lfn,
 163                                 dir_entry->namebuf.lfnbuf_len);
 164                         brelse(bh);
 165
 166                         ep = exfat_get_dentry(sb, &clu, i + 1, &bh);
 167                         if (!ep)
 168                                 return -EIO;
 169                         dir_entry->size =
 170                                 le64_to_cpu(ep->dentry.stream.valid_size);
 171                         dir_entry->entry = dentry;
 172                         brelse(bh);
 173
 174                         ei->hint_bmap.off = EXFAT_DEN_TO_CLU(dentry, sbi);
 175                         ei->hint_bmap.clu = clu.dir;
 176
 177                         *cpos = EXFAT_DEN_TO_B(dentry + 1 + num_ext);
 178                         return 0;
 179                 }
 180
 181                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 182                         if (--clu.size > 0)
 183                                 clu.dir++;
 184                         else
 185                                 clu.dir = EXFAT_EOF_CLUSTER;
 186                 } else {
 187                         if (exfat_get_next_cluster(sb, &(clu.dir)))
 188                                 return -EIO;
 189                 }
 190         }
 191
 192         dir_entry->namebuf.lfn[0] = '\0';
 193         *cpos = EXFAT_DEN_TO_B(dentry);
 194         return 0;
 195 }
 196
 197 static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
 198 {
 199         nb->lfn = NULL;
 200         nb->lfnbuf_len = 0;
 201 }
 202
 203 static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
 204 {
 205         nb->lfn = __getname();
 206         if (!nb->lfn)
 207                 return -ENOMEM;
 208         nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
 209         return 0;
 210 }
 211
 212 static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 213 {
 214         if (!nb->lfn)
 215                 return;
 216
 217         __putname(nb->lfn);
 218         exfat_init_namebuf(nb);
 219 }
 220
 221 /*
 222  * Before calling dir_emit*(), sbi->s_lock should be released
 223  * because page fault can occur in dir_emit*().
 224  */
 225 #define ITER_POS_FILLED_DOTS    (2)
 226 static int exfat_iterate(struct file *file, struct dir_context *ctx)
 227 {
 228         struct inode *inode = file_inode(file);
 229         struct super_block *sb = inode->i_sb;
 230         struct inode *tmp;
 231         struct exfat_dir_entry de;
 232         struct exfat_dentry_namebuf *nb = &(de.namebuf);
 233         struct exfat_inode_info *ei = EXFAT_I(inode);
 234         unsigned long inum;
 235         loff_t cpos, i_pos;
 236         int err = 0, fake_offset = 0;
 237
 238         exfat_init_namebuf(nb);
 239
 240         cpos = ctx->pos;
 241         if (!dir_emit_dots(file, ctx))
 242                 goto out;
 243
 244         if (ctx->pos == ITER_POS_FILLED_DOTS) {
 245                 cpos = 0;
 246                 fake_offset = 1;
 247         }
 248
 249         cpos = round_up(cpos, DENTRY_SIZE);
 250
 251         /* name buffer should be allocated before use */
 252         err = exfat_alloc_namebuf(nb);
 253         if (err)
 254                 goto out;
 255 get_new:
 256         mutex_lock(&EXFAT_SB(sb)->s_lock);
 257
 258         if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 259                 goto end_of_dir;
 260
 261         err = exfat_readdir(inode, &cpos, &de);
 262         if (err) {
 263                 /*
 264                  * At least we tried to read a sector.
 265                  * Move cpos to next sector position (should be aligned).
 266                  */
 267                 if (err == -EIO) {
 268                         cpos += 1 << (sb->s_blocksize_bits);
 269                         cpos &= ~(sb->s_blocksize - 1);
 270                 }
 271
 272                 err = -EIO;
 273                 goto end_of_dir;
 274         }
 275
 276         if (!nb->lfn[0])
 277                 goto end_of_dir;
 278
 279         i_pos = ((loff_t)ei->start_clu << 32) | (de.entry & 0xffffffff);
 280         tmp = exfat_iget(sb, i_pos);
 281         if (tmp) {
 282                 inum = tmp->i_ino;
 283                 iput(tmp);
 284         } else {
 285                 inum = iunique(sb, EXFAT_ROOT_INO);
 286         }
 287
 288         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 289         if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 290                         (de.attr & EXFAT_ATTR_SUBDIR) ? DT_DIR : DT_REG))
 291                 goto out;
 292         ctx->pos = cpos;
 293         goto get_new;
 294
 295 end_of_dir:
 296         if (!cpos && fake_offset)
 297                 cpos = ITER_POS_FILLED_DOTS;
 298         ctx->pos = cpos;
 299         mutex_unlock(&EXFAT_SB(sb)->s_lock);
 300 out:
 301         /*
 302          * To improve performance, free namebuf after unlock sb_lock.
 303          * If namebuf is not allocated, this function do nothing
 304          */
 305         exfat_free_namebuf(nb);
 306         return err;
 307 }
 308
 309 WRAP_DIR_ITER(exfat_iterate) // FIXME!
 310 const struct file_operations exfat_dir_operations = {
 311         .llseek         = generic_file_llseek,
 312         .read           = generic_read_dir,
 313         .iterate_shared = shared_exfat_iterate,
 314         .unlocked_ioctl = exfat_ioctl,
 315 #ifdef CONFIG_COMPAT
 316         .compat_ioctl = exfat_compat_ioctl,
 317 #endif
 318         .fsync          = exfat_file_fsync,
 319 };
 320
 321 int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 322 {
 323         int ret;
 324
 325         exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 326
 327         ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 328         if (ret)
 329                 return ret;
 330
 331         return exfat_zeroed_cluster(inode, clu->dir);
 332 }
 333
 334 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
 335 {
 336         int len;
 337
 338         len = p_uniname->name_len;
 339         if (len == 0)
 340                 return -EINVAL;
 341
 342         /* 1 file entry + 1 stream entry + name entries */
 343         return ES_ENTRY_NUM(len);
 344 }
 345
 346 unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 347 {
 348         if (ep->type == EXFAT_UNUSED)
 349                 return TYPE_UNUSED;
 350         if (IS_EXFAT_DELETED(ep->type))
 351                 return TYPE_DELETED;
 352         if (ep->type == EXFAT_INVAL)
 353                 return TYPE_INVALID;
 354         if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
 355                 if (ep->type == EXFAT_BITMAP)
 356                         return TYPE_BITMAP;
 357                 if (ep->type == EXFAT_UPCASE)
 358                         return TYPE_UPCASE;
 359                 if (ep->type == EXFAT_VOLUME)
 360                         return TYPE_VOLUME;
 361                 if (ep->type == EXFAT_FILE) {
 362                         if (le16_to_cpu(ep->dentry.file.attr) & EXFAT_ATTR_SUBDIR)
 363                                 return TYPE_DIR;
 364                         return TYPE_FILE;
 365                 }
 366                 return TYPE_CRITICAL_PRI;
 367         }
 368         if (IS_EXFAT_BENIGN_PRI(ep->type)) {
 369                 if (ep->type == EXFAT_GUID)
 370                         return TYPE_GUID;
 371                 if (ep->type == EXFAT_PADDING)
 372                         return TYPE_PADDING;
 373                 if (ep->type == EXFAT_ACLTAB)
 374                         return TYPE_ACLTAB;
 375                 return TYPE_BENIGN_PRI;
 376         }
 377         if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
 378                 if (ep->type == EXFAT_STREAM)
 379                         return TYPE_STREAM;
 380                 if (ep->type == EXFAT_NAME)
 381                         return TYPE_EXTEND;
 382                 if (ep->type == EXFAT_ACL)
 383                         return TYPE_ACL;
 384                 return TYPE_CRITICAL_SEC;
 385         }
 386
 387         if (ep->type == EXFAT_VENDOR_EXT)
 388                 return TYPE_VENDOR_EXT;
 389         if (ep->type == EXFAT_VENDOR_ALLOC)
 390                 return TYPE_VENDOR_ALLOC;
 391
 392         return TYPE_BENIGN_SEC;
 393 }
 394
 395 static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
 396 {
 397         if (type == TYPE_UNUSED) {
 398                 ep->type = EXFAT_UNUSED;
 399         } else if (type == TYPE_DELETED) {
 400                 ep->type &= EXFAT_DELETE;
 401         } else if (type == TYPE_STREAM) {
 402                 ep->type = EXFAT_STREAM;
 403         } else if (type == TYPE_EXTEND) {
 404                 ep->type = EXFAT_NAME;
 405         } else if (type == TYPE_BITMAP) {
 406                 ep->type = EXFAT_BITMAP;
 407         } else if (type == TYPE_UPCASE) {
 408                 ep->type = EXFAT_UPCASE;
 409         } else if (type == TYPE_VOLUME) {
 410                 ep->type = EXFAT_VOLUME;
 411         } else if (type == TYPE_DIR) {
 412                 ep->type = EXFAT_FILE;
 413                 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_SUBDIR);
 414         } else if (type == TYPE_FILE) {
 415                 ep->type = EXFAT_FILE;
 416                 ep->dentry.file.attr = cpu_to_le16(EXFAT_ATTR_ARCHIVE);
 417         }
 418 }
 419
 420 static void exfat_init_stream_entry(struct exfat_dentry *ep,
 421                 unsigned int start_clu, unsigned long long size)
 422 {
 423         exfat_set_entry_type(ep, TYPE_STREAM);
 424         if (size == 0)
 425                 ep->dentry.stream.flags = ALLOC_FAT_CHAIN;
 426         else
 427                 ep->dentry.stream.flags = ALLOC_NO_FAT_CHAIN;
 428         ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
 429         ep->dentry.stream.valid_size = cpu_to_le64(size);
 430         ep->dentry.stream.size = cpu_to_le64(size);
 431 }
 432
 433 static void exfat_init_name_entry(struct exfat_dentry *ep,
 434                 unsigned short *uniname)
 435 {
 436         int i;
 437
 438         exfat_set_entry_type(ep, TYPE_EXTEND);
 439         ep->dentry.name.flags = 0x0;
 440
 441         for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
 442                 if (*uniname != 0x0) {
 443                         ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
 444                         uniname++;
 445                 } else {
 446                         ep->dentry.name.unicode_0_14[i] = 0x0;
 447                 }
 448         }
 449 }
 450
 451 int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 452                 int entry, unsigned int type, unsigned int start_clu,
 453                 unsigned long long size)
 454 {
 455         struct super_block *sb = inode->i_sb;
 456         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 457         struct timespec64 ts = current_time(inode);
 458         struct exfat_dentry *ep;
 459         struct buffer_head *bh;
 460
 461         /*
 462          * We cannot use exfat_get_dentry_set here because file ep is not
 463          * initialized yet.
 464          */
 465         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
 466         if (!ep)
 467                 return -EIO;
 468
 469         exfat_set_entry_type(ep, type);
 470         exfat_set_entry_time(sbi, &ts,
 471                         &ep->dentry.file.create_tz,
 472                         &ep->dentry.file.create_time,
 473                         &ep->dentry.file.create_date,
 474                         &ep->dentry.file.create_time_cs);
 475         exfat_set_entry_time(sbi, &ts,
 476                         &ep->dentry.file.modify_tz,
 477                         &ep->dentry.file.modify_time,
 478                         &ep->dentry.file.modify_date,
 479                         &ep->dentry.file.modify_time_cs);
 480         exfat_set_entry_time(sbi, &ts,
 481                         &ep->dentry.file.access_tz,
 482                         &ep->dentry.file.access_time,
 483                         &ep->dentry.file.access_date,
 484                         NULL);
 485
 486         exfat_update_bh(bh, IS_DIRSYNC(inode));
 487         brelse(bh);
 488
 489         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
 490         if (!ep)
 491                 return -EIO;
 492
 493         exfat_init_stream_entry(ep, start_clu, size);
 494         exfat_update_bh(bh, IS_DIRSYNC(inode));
 495         brelse(bh);
 496
 497         return 0;
 498 }
 499
 500 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 501                 int entry)
 502 {
 503         struct super_block *sb = inode->i_sb;
 504         int ret = 0;
 505         int i, num_entries;
 506         u16 chksum;
 507         struct exfat_dentry *ep, *fep;
 508         struct buffer_head *fbh, *bh;
 509
 510         fep = exfat_get_dentry(sb, p_dir, entry, &fbh);
 511         if (!fep)
 512                 return -EIO;
 513
 514         num_entries = fep->dentry.file.num_ext + 1;
 515         chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 516
 517         for (i = 1; i < num_entries; i++) {
 518                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 519                 if (!ep) {
 520                         ret = -EIO;
 521                         goto release_fbh;
 522                 }
 523                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 524                                 CS_DEFAULT);
 525                 brelse(bh);
 526         }
 527
 528         fep->dentry.file.checksum = cpu_to_le16(chksum);
 529         exfat_update_bh(fbh, IS_DIRSYNC(inode));
 530 release_fbh:
 531         brelse(fbh);
 532         return ret;
 533 }
 534
 535 static void exfat_free_benign_secondary_clusters(struct inode *inode,
 536                 struct exfat_dentry *ep)
 537 {
 538         struct super_block *sb = inode->i_sb;
 539         struct exfat_chain dir;
 540         unsigned int start_clu =
 541                 le32_to_cpu(ep->dentry.generic_secondary.start_clu);
 542         u64 size = le64_to_cpu(ep->dentry.generic_secondary.size);
 543         unsigned char flags = ep->dentry.generic_secondary.flags;
 544
 545         if (!(flags & ALLOC_POSSIBLE) || !start_clu || !size)
 546                 return;
 547
 548         exfat_chain_set(&dir, start_clu,
 549                         EXFAT_B_TO_CLU_ROUND_UP(size, EXFAT_SB(sb)),
 550                         flags);
 551         exfat_free_cluster(inode, &dir);
 552 }
 553
 554 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 555                 int entry, int num_entries, struct exfat_uni_name *p_uniname)
 556 {
 557         struct super_block *sb = inode->i_sb;
 558         int i;
 559         unsigned short *uniname = p_uniname->name;
 560         struct exfat_dentry *ep;
 561         struct buffer_head *bh;
 562         int sync = IS_DIRSYNC(inode);
 563
 564         ep = exfat_get_dentry(sb, p_dir, entry, &bh);
 565         if (!ep)
 566                 return -EIO;
 567
 568         ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
 569         exfat_update_bh(bh, sync);
 570         brelse(bh);
 571
 572         ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh);
 573         if (!ep)
 574                 return -EIO;
 575
 576         ep->dentry.stream.name_len = p_uniname->name_len;
 577         ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
 578         exfat_update_bh(bh, sync);
 579         brelse(bh);
 580
 581         for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
 582                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 583                 if (!ep)
 584                         return -EIO;
 585
 586                 if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
 587                         exfat_free_benign_secondary_clusters(inode, ep);
 588
 589                 exfat_init_name_entry(ep, uniname);
 590                 exfat_update_bh(bh, sync);
 591                 brelse(bh);
 592                 uniname += EXFAT_FILE_NAME_LEN;
 593         }
 594
 595         exfat_update_dir_chksum(inode, p_dir, entry);
 596         return 0;
 597 }
 598
 599 int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 600                 int entry, int order, int num_entries)
 601 {
 602         struct super_block *sb = inode->i_sb;
 603         int i;
 604         struct exfat_dentry *ep;
 605         struct buffer_head *bh;
 606
 607         for (i = order; i < num_entries; i++) {
 608                 ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 609                 if (!ep)
 610                         return -EIO;
 611
 612                 if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
 613                         exfat_free_benign_secondary_clusters(inode, ep);
 614
 615                 exfat_set_entry_type(ep, TYPE_DELETED);
 616                 exfat_update_bh(bh, IS_DIRSYNC(inode));
 617                 brelse(bh);
 618         }
 619
 620         return 0;
 621 }
 622
 623 void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 624 {
 625         int chksum_type = CS_DIR_ENTRY, i;
 626         unsigned short chksum = 0;
 627         struct exfat_dentry *ep;
 628
 629         for (i = ES_IDX_FILE; i < es->num_entries; i++) {
 630                 ep = exfat_get_dentry_cached(es, i);
 631                 chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 632                                              chksum_type);
 633                 chksum_type = CS_DEFAULT;
 634         }
 635         ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 636         ep->dentry.file.checksum = cpu_to_le16(chksum);
 637         es->modified = true;
 638 }
 639
 640 int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync)
 641 {
 642         int i, err = 0;
 643
 644         if (es->modified)
 645                 err = exfat_update_bhs(es->bh, es->num_bh, sync);
 646
 647         for (i = 0; i < es->num_bh; i++)
 648                 if (err)
 649                         bforget(es->bh[i]);
 650                 else
 651                         brelse(es->bh[i]);
 652
 653         if (IS_DYNAMIC_ES(es))
 654                 kfree(es->bh);
 655
 656         return err;
 657 }
 658
 659 static int exfat_walk_fat_chain(struct super_block *sb,
 660                 struct exfat_chain *p_dir, unsigned int byte_offset,
 661                 unsigned int *clu)
 662 {
 663         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 664         unsigned int clu_offset;
 665         unsigned int cur_clu;
 666
 667         clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
 668         cur_clu = p_dir->dir;
 669
 670         if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
 671                 cur_clu += clu_offset;
 672         } else {
 673                 while (clu_offset > 0) {
 674                         if (exfat_get_next_cluster(sb, &cur_clu))
 675                                 return -EIO;
 676                         if (cur_clu == EXFAT_EOF_CLUSTER) {
 677                                 exfat_fs_error(sb,
 678                                         "invalid dentry access beyond EOF (clu : %u, eidx : %d)",
 679                                         p_dir->dir,
 680                                         EXFAT_B_TO_DEN(byte_offset));
 681                                 return -EIO;
 682                         }
 683                         clu_offset--;
 684                 }
 685         }
 686
 687         *clu = cur_clu;
 688         return 0;
 689 }
 690
 691 static int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 692                                int entry, sector_t *sector, int *offset)
 693 {
 694         int ret;
 695         unsigned int off, clu = 0;
 696         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 697
 698         off = EXFAT_DEN_TO_B(entry);
 699
 700         ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
 701         if (ret)
 702                 return ret;
 703
 704         /* byte offset in cluster */
 705         off = EXFAT_CLU_OFFSET(off, sbi);
 706
 707         /* byte offset in sector    */
 708         *offset = EXFAT_BLK_OFFSET(off, sb);
 709
 710         /* sector offset in cluster */
 711         *sector = EXFAT_B_TO_BLK(off, sb);
 712         *sector += exfat_cluster_to_sector(sbi, clu);
 713         return 0;
 714 }
 715
 716 #define EXFAT_MAX_RA_SIZE     (128*1024)
 717 static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 718 {
 719         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 720         struct buffer_head *bh;
 721         unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
 722         unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
 723         unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
 724         unsigned int ra_count = min(adj_ra_count, max_ra_count);
 725
 726         /* Read-ahead is not required */
 727         if (sbi->sect_per_clus == 1)
 728                 return 0;
 729
 730         if (sec < sbi->data_start_sector) {
 731                 exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
 732                           (unsigned long long)sec, sbi->data_start_sector);
 733                 return -EIO;
 734         }
 735
 736         /* Not sector aligned with ra_count, resize ra_count to page size */
 737         if ((sec - sbi->data_start_sector) & (ra_count - 1))
 738                 ra_count = page_ra_count;
 739
 740         bh = sb_find_get_block(sb, sec);
 741         if (!bh || !buffer_uptodate(bh)) {
 742                 unsigned int i;
 743
 744                 for (i = 0; i < ra_count; i++)
 745                         sb_breadahead(sb, (sector_t)(sec + i));
 746         }
 747         brelse(bh);
 748         return 0;
 749 }
 750
 751 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 752                 struct exfat_chain *p_dir, int entry, struct buffer_head **bh)
 753 {
 754         unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
 755         int off;
 756         sector_t sec;
 757
 758         if (p_dir->dir == DIR_DELETED) {
 759                 exfat_err(sb, "abnormal access to deleted dentry");
 760                 return NULL;
 761         }
 762
 763         if (exfat_find_location(sb, p_dir, entry, &sec, &off))
 764                 return NULL;
 765
 766         if (p_dir->dir != EXFAT_FREE_CLUSTER &&
 767                         !(entry & (dentries_per_page - 1)))
 768                 exfat_dir_readahead(sb, sec);
 769
 770         *bh = sb_bread(sb, sec);
 771         if (!*bh)
 772                 return NULL;
 773
 774         return (struct exfat_dentry *)((*bh)->b_data + off);
 775 }
 776
 777 enum exfat_validate_dentry_mode {
 778         ES_MODE_STARTED,
 779         ES_MODE_GET_FILE_ENTRY,
 780         ES_MODE_GET_STRM_ENTRY,
 781         ES_MODE_GET_NAME_ENTRY,
 782         ES_MODE_GET_CRITICAL_SEC_ENTRY,
 783         ES_MODE_GET_BENIGN_SEC_ENTRY,
 784 };
 785
 786 static bool exfat_validate_entry(unsigned int type,
 787                 enum exfat_validate_dentry_mode *mode)
 788 {
 789         if (type == TYPE_UNUSED || type == TYPE_DELETED)
 790                 return false;
 791
 792         switch (*mode) {
 793         case ES_MODE_STARTED:
 794                 if  (type != TYPE_FILE && type != TYPE_DIR)
 795                         return false;
 796                 *mode = ES_MODE_GET_FILE_ENTRY;
 797                 break;
 798         case ES_MODE_GET_FILE_ENTRY:
 799                 if (type != TYPE_STREAM)
 800                         return false;
 801                 *mode = ES_MODE_GET_STRM_ENTRY;
 802                 break;
 803         case ES_MODE_GET_STRM_ENTRY:
 804                 if (type != TYPE_EXTEND)
 805                         return false;
 806                 *mode = ES_MODE_GET_NAME_ENTRY;
 807                 break;
 808         case ES_MODE_GET_NAME_ENTRY:
 809                 if (type & TYPE_BENIGN_SEC)
 810                         *mode = ES_MODE_GET_BENIGN_SEC_ENTRY;
 811                 else if (type != TYPE_EXTEND)
 812                         return false;
 813                 break;
 814         case ES_MODE_GET_BENIGN_SEC_ENTRY:
 815                 /* Assume unreconized benign secondary entry */
 816                 if (!(type & TYPE_BENIGN_SEC))
 817                         return false;
 818                 break;
 819         default:
 820                 return false;
 821         }
 822
 823         return true;
 824 }
 825
 826 struct exfat_dentry *exfat_get_dentry_cached(
 827         struct exfat_entry_set_cache *es, int num)
 828 {
 829         int off = es->start_off + num * DENTRY_SIZE;
 830         struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
 831         char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
 832
 833         return (struct exfat_dentry *)p;
 834 }
 835
 836 /*
 837  * Returns a set of dentries for a file or dir.
 838  *
 839  * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
 840  * User should call exfat_get_dentry_set() after setting 'modified' to apply
 841  * changes made in this entry set to the real device.
 842  *
 843  * in:
 844  *   sb+p_dir+entry: indicates a file/dir
 845  *   type:  specifies how many dentries should be included.
 846  * return:
 847  *   pointer of entry set on success,
 848  *   NULL on failure.
 849  */
 850 int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
 851                 struct super_block *sb, struct exfat_chain *p_dir, int entry,
 852                 unsigned int type)
 853 {
 854         int ret, i, num_bh;
 855         unsigned int off;
 856         sector_t sec;
 857         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 858         struct exfat_dentry *ep;
 859         int num_entries;
 860         enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 861         struct buffer_head *bh;
 862
 863         if (p_dir->dir == DIR_DELETED) {
 864                 exfat_err(sb, "access to deleted dentry");
 865                 return -EIO;
 866         }
 867
 868         ret = exfat_find_location(sb, p_dir, entry, &sec, &off);
 869         if (ret)
 870                 return ret;
 871
 872         memset(es, 0, sizeof(*es));
 873         es->sb = sb;
 874         es->modified = false;
 875         es->start_off = off;
 876         es->bh = es->__bh;
 877
 878         bh = sb_bread(sb, sec);
 879         if (!bh)
 880                 return -EIO;
 881         es->bh[es->num_bh++] = bh;
 882
 883         ep = exfat_get_dentry_cached(es, ES_IDX_FILE);
 884         if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 885                 goto put_es;
 886
 887         num_entries = type == ES_ALL_ENTRIES ?
 888                 ep->dentry.file.num_ext + 1 : type;
 889         es->num_entries = num_entries;
 890
 891         num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
 892         if (num_bh > ARRAY_SIZE(es->__bh)) {
 893                 es->bh = kmalloc_array(num_bh, sizeof(*es->bh), GFP_KERNEL);
 894                 if (!es->bh) {
 895                         brelse(bh);
 896                         return -ENOMEM;
 897                 }
 898                 es->bh[0] = bh;
 899         }
 900
 901         for (i = 1; i < num_bh; i++) {
 902                 /* get the next sector */
 903                 if (exfat_is_last_sector_in_cluster(sbi, sec)) {
 904                         unsigned int clu = exfat_sector_to_cluster(sbi, sec);
 905
 906                         if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
 907                                 clu++;
 908                         else if (exfat_get_next_cluster(sb, &clu))
 909                                 goto put_es;
 910                         sec = exfat_cluster_to_sector(sbi, clu);
 911                 } else {
 912                         sec++;
 913                 }
 914
 915                 bh = sb_bread(sb, sec);
 916                 if (!bh)
 917                         goto put_es;
 918                 es->bh[es->num_bh++] = bh;
 919         }
 920
 921         /* validate cached dentries */
 922         for (i = ES_IDX_STREAM; i < num_entries; i++) {
 923                 ep = exfat_get_dentry_cached(es, i);
 924                 if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
 925                         goto put_es;
 926         }
 927         return 0;
 928
 929 put_es:
 930         exfat_put_dentry_set(es, false);
 931         return -EIO;
 932 }
 933
 934 static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp)
 935 {
 936         hint_femp->eidx = EXFAT_HINT_NONE;
 937         hint_femp->count = 0;
 938 }
 939
 940 static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
 941                 struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
 942                 int dentry, int num_entries, int entry_type)
 943 {
 944         if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
 945             ei->hint_femp.eidx > dentry) {
 946                 int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode));
 947
 948                 if (candi_empty->count == 0) {
 949                         candi_empty->cur = *clu;
 950                         candi_empty->eidx = dentry;
 951                 }
 952
 953                 if (entry_type == TYPE_UNUSED)
 954                         candi_empty->count += total_entries - dentry;
 955                 else
 956                         candi_empty->count++;
 957
 958                 if (candi_empty->count == num_entries ||
 959                     candi_empty->count + candi_empty->eidx == total_entries)
 960                         ei->hint_femp = *candi_empty;
 961         }
 962 }
 963
 964 enum {
 965         DIRENT_STEP_FILE,
 966         DIRENT_STEP_STRM,
 967         DIRENT_STEP_NAME,
 968         DIRENT_STEP_SECD,
 969 };
 970
 971 /*
 972  * @ei:         inode info of parent directory
 973  * @p_dir:      directory structure of parent directory
 974  * @num_entries:entry size of p_uniname
 975  * @hint_opt:   If p_uniname is found, filled with optimized dir/entry
 976  *              for traversing cluster chain.
 977  * @return:
 978  *   >= 0:      file directory entry position where the name exists
 979  *   -ENOENT:   entry with the name does not exist
 980  *   -EIO:      I/O error
 981  */
 982 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 983                 struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
 984                 struct exfat_hint *hint_opt)
 985 {
 986         int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
 987         int order, step, name_len = 0;
 988         int dentries_per_clu;
 989         unsigned int entry_type;
 990         unsigned short *uniname = NULL;
 991         struct exfat_chain clu;
 992         struct exfat_hint *hint_stat = &ei->hint_stat;
 993         struct exfat_hint_femp candi_empty;
 994         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 995         int num_entries = exfat_calc_num_entries(p_uniname);
 996
 997         if (num_entries < 0)
 998                 return num_entries;
 999
1000         dentries_per_clu = sbi->dentries_per_clu;
1001
1002         exfat_chain_dup(&clu, p_dir);
1003
1004         if (hint_stat->eidx) {
1005                 clu.dir = hint_stat->clu;
1006                 dentry = hint_stat->eidx;
1007                 end_eidx = dentry;
1008         }
1009
1010         exfat_reset_empty_hint(&ei->hint_femp);
1011
1012 rewind:
1013         order = 0;
1014         step = DIRENT_STEP_FILE;
1015         exfat_reset_empty_hint(&candi_empty);
1016
1017         while (clu.dir != EXFAT_EOF_CLUSTER) {
1018                 i = dentry & (dentries_per_clu - 1);
1019                 for (; i < dentries_per_clu; i++, dentry++) {
1020                         struct exfat_dentry *ep;
1021                         struct buffer_head *bh;
1022
1023                         if (rewind && dentry == end_eidx)
1024                                 goto not_found;
1025
1026                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1027                         if (!ep)
1028                                 return -EIO;
1029
1030                         entry_type = exfat_get_entry_type(ep);
1031
1032                         if (entry_type == TYPE_UNUSED ||
1033                             entry_type == TYPE_DELETED) {
1034                                 step = DIRENT_STEP_FILE;
1035
1036                                 exfat_set_empty_hint(ei, &candi_empty, &clu,
1037                                                 dentry, num_entries,
1038                                                 entry_type);
1039
1040                                 brelse(bh);
1041                                 if (entry_type == TYPE_UNUSED)
1042                                         goto not_found;
1043                                 continue;
1044                         }
1045
1046                         exfat_reset_empty_hint(&candi_empty);
1047
1048                         if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
1049                                 step = DIRENT_STEP_FILE;
1050                                 hint_opt->clu = clu.dir;
1051                                 hint_opt->eidx = i;
1052                                 num_ext = ep->dentry.file.num_ext;
1053                                 step = DIRENT_STEP_STRM;
1054                                 brelse(bh);
1055                                 continue;
1056                         }
1057
1058                         if (entry_type == TYPE_STREAM) {
1059                                 u16 name_hash;
1060
1061                                 if (step != DIRENT_STEP_STRM) {
1062                                         step = DIRENT_STEP_FILE;
1063                                         brelse(bh);
1064                                         continue;
1065                                 }
1066                                 step = DIRENT_STEP_FILE;
1067                                 name_hash = le16_to_cpu(
1068                                                 ep->dentry.stream.name_hash);
1069                                 if (p_uniname->name_hash == name_hash &&
1070                                     p_uniname->name_len ==
1071                                                 ep->dentry.stream.name_len) {
1072                                         step = DIRENT_STEP_NAME;
1073                                         order = 1;
1074                                         name_len = 0;
1075                                 }
1076                                 brelse(bh);
1077                                 continue;
1078                         }
1079
1080                         brelse(bh);
1081                         if (entry_type == TYPE_EXTEND) {
1082                                 unsigned short entry_uniname[16], unichar;
1083
1084                                 if (step != DIRENT_STEP_NAME ||
1085                                     name_len >= MAX_NAME_LENGTH) {
1086                                         step = DIRENT_STEP_FILE;
1087                                         continue;
1088                                 }
1089
1090                                 if (++order == 2)
1091                                         uniname = p_uniname->name;
1092                                 else
1093                                         uniname += EXFAT_FILE_NAME_LEN;
1094
1095                                 len = exfat_extract_uni_name(ep, entry_uniname);
1096                                 name_len += len;
1097
1098                                 unichar = *(uniname+len);
1099                                 *(uniname+len) = 0x0;
1100
1101                                 if (exfat_uniname_ncmp(sb, uniname,
1102                                         entry_uniname, len)) {
1103                                         step = DIRENT_STEP_FILE;
1104                                 } else if (p_uniname->name_len == name_len) {
1105                                         if (order == num_ext)
1106                                                 goto found;
1107                                         step = DIRENT_STEP_SECD;
1108                                 }
1109
1110                                 *(uniname+len) = unichar;
1111                                 continue;
1112                         }
1113
1114                         if (entry_type &
1115                                         (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
1116                                 if (step == DIRENT_STEP_SECD) {
1117                                         if (++order == num_ext)
1118                                                 goto found;
1119                                         continue;
1120                                 }
1121                         }
1122                         step = DIRENT_STEP_FILE;
1123                 }
1124
1125                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1126                         if (--clu.size > 0)
1127                                 clu.dir++;
1128                         else
1129                                 clu.dir = EXFAT_EOF_CLUSTER;
1130                 } else {
1131                         if (exfat_get_next_cluster(sb, &clu.dir))
1132                                 return -EIO;
1133                 }
1134         }
1135
1136 not_found:
1137         /*
1138          * We started at not 0 index,so we should try to find target
1139          * from 0 index to the index we started at.
1140          */
1141         if (!rewind && end_eidx) {
1142                 rewind = 1;
1143                 dentry = 0;
1144                 clu.dir = p_dir->dir;
1145                 goto rewind;
1146         }
1147
1148         /*
1149          * set the EXFAT_EOF_CLUSTER flag to avoid search
1150          * from the beginning again when allocated a new cluster
1151          */
1152         if (ei->hint_femp.eidx == EXFAT_HINT_NONE) {
1153                 ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER;
1154                 ei->hint_femp.eidx = p_dir->size * dentries_per_clu;
1155                 ei->hint_femp.count = 0;
1156         }
1157
1158         /* initialized hint_stat */
1159         hint_stat->clu = p_dir->dir;
1160         hint_stat->eidx = 0;
1161         return -ENOENT;
1162
1163 found:
1164         /* next dentry we'll find is out of this cluster */
1165         if (!((dentry + 1) & (dentries_per_clu - 1))) {
1166                 int ret = 0;
1167
1168                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1169                         if (--clu.size > 0)
1170                                 clu.dir++;
1171                         else
1172                                 clu.dir = EXFAT_EOF_CLUSTER;
1173                 } else {
1174                         ret = exfat_get_next_cluster(sb, &clu.dir);
1175                 }
1176
1177                 if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
1178                         /* just initialized hint_stat */
1179                         hint_stat->clu = p_dir->dir;
1180                         hint_stat->eidx = 0;
1181                         return (dentry - num_ext);
1182                 }
1183         }
1184
1185         hint_stat->clu = clu.dir;
1186         hint_stat->eidx = dentry + 1;
1187         return dentry - num_ext;
1188 }
1189
1190 int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
1191                 int entry, struct exfat_dentry *ep)
1192 {
1193         int i, count = 0;
1194         unsigned int type;
1195         struct exfat_dentry *ext_ep;
1196         struct buffer_head *bh;
1197
1198         for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
1199                 ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh);
1200                 if (!ext_ep)
1201                         return -EIO;
1202
1203                 type = exfat_get_entry_type(ext_ep);
1204                 brelse(bh);
1205                 if (type & TYPE_CRITICAL_SEC || type & TYPE_BENIGN_SEC)
1206                         count++;
1207         }
1208         return count;
1209 }
1210
1211 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
1212 {
1213         int i, count = 0;
1214         int dentries_per_clu;
1215         unsigned int entry_type;
1216         struct exfat_chain clu;
1217         struct exfat_dentry *ep;
1218         struct exfat_sb_info *sbi = EXFAT_SB(sb);
1219         struct buffer_head *bh;
1220
1221         dentries_per_clu = sbi->dentries_per_clu;
1222
1223         exfat_chain_dup(&clu, p_dir);
1224
1225         while (clu.dir != EXFAT_EOF_CLUSTER) {
1226                 for (i = 0; i < dentries_per_clu; i++) {
1227                         ep = exfat_get_dentry(sb, &clu, i, &bh);
1228                         if (!ep)
1229                                 return -EIO;
1230                         entry_type = exfat_get_entry_type(ep);
1231                         brelse(bh);
1232
1233                         if (entry_type == TYPE_UNUSED)
1234                                 return count;
1235                         if (entry_type != TYPE_DIR)
1236                                 continue;
1237                         count++;
1238                 }
1239
1240                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
1241                         if (--clu.size > 0)
1242                                 clu.dir++;
1243                         else
1244                                 clu.dir = EXFAT_EOF_CLUSTER;
1245                 } else {
1246                         if (exfat_get_next_cluster(sb, &(clu.dir)))
1247                                 return -EIO;
1248                 }
1249         }
1250
1251         return count;
1252 }