fs/fat/dir.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
fat_tolower
fat_make_i_pos
fat_dir_readahead
fat__get_entry
fat_get_entry
uni16_to_x8
fat_uni_to_x8
fat_short2uni
fat_short2lower_uni
fat_shortname2uni
fat_name_match
fat_parse_long
fat_parse_short
fat_search_long
__fat_readdir
fat_readdir
FAT_IOCTL_FILLDIR_FUNC
fat_dir_ioctl
fat_compat_dir_ioctl
fat_get_short_entry
fat_get_dotdot_entry
fat_dir_empty
fat_subdirs
fat_scan
fat_scan_logstart
__fat_remove_entries
fat_remove_entries
fat_zeroed_cluster
fat_alloc_new_dir
fat_add_new_entries
fat_add_entries
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/fat/dir.c
   4  *
   5  *  directory handling functions for fat-based filesystems
   6  *
   7  *  Written 1992,1993 by Werner Almesberger
   8  *
   9  *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
  10  *
  11  *  VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
  12  *  Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
  13  *  Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
  14  *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
  15  */
  16 
  17 #include <linux/slab.h>
  18 #include <linux/compat.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/iversion.h>
  21 #include "fat.h"
  22 
  23 /*
  24  * Maximum buffer size of short name.
  25  * [(MSDOS_NAME + '.') * max one char + nul]
  26  * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
  27  */
  28 #define FAT_MAX_SHORT_SIZE      ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
  29 /*
  30  * Maximum buffer size of unicode chars from slots.
  31  * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
  32  */
  33 #define FAT_MAX_UNI_CHARS       ((MSDOS_SLOTS - 1) * 13 + 1)
  34 #define FAT_MAX_UNI_SIZE        (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
  35 
  36 static inline unsigned char fat_tolower(unsigned char c)
  37 {
  38         return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
  39 }
  40 
  41 static inline loff_t fat_make_i_pos(struct super_block *sb,
  42                                     struct buffer_head *bh,
  43                                     struct msdos_dir_entry *de)
  44 {
  45         return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
  46                 | (de - (struct msdos_dir_entry *)bh->b_data);
  47 }
  48 
  49 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
  50                                      sector_t phys)
  51 {
  52         struct super_block *sb = dir->i_sb;
  53         struct msdos_sb_info *sbi = MSDOS_SB(sb);
  54         struct buffer_head *bh;
  55         int sec;
  56 
  57         /* This is not a first sector of cluster, or sec_per_clus == 1 */
  58         if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
  59                 return;
  60         /* root dir of FAT12/FAT16 */
  61         if (!is_fat32(sbi) && (dir->i_ino == MSDOS_ROOT_INO))
  62                 return;
  63 
  64         bh = sb_find_get_block(sb, phys);
  65         if (bh == NULL || !buffer_uptodate(bh)) {
  66                 for (sec = 0; sec < sbi->sec_per_clus; sec++)
  67                         sb_breadahead(sb, phys + sec);
  68         }
  69         brelse(bh);
  70 }
  71 
  72 /* Returns the inode number of the directory entry at offset pos. If bh is
  73    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
  74    returned in bh.
  75    AV. Most often we do it item-by-item. Makes sense to optimize.
  76    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
  77    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
  78    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
  79    AV. Additionally, when we return -1 (i.e. reached the end of directory)
  80    AV. we make bh NULL.
  81  */
  82 static int fat__get_entry(struct inode *dir, loff_t *pos,
  83                           struct buffer_head **bh, struct msdos_dir_entry **de)
  84 {
  85         struct super_block *sb = dir->i_sb;
  86         sector_t phys, iblock;
  87         unsigned long mapped_blocks;
  88         int err, offset;
  89 
  90 next:
  91         brelse(*bh);
  92         *bh = NULL;
  93         iblock = *pos >> sb->s_blocksize_bits;
  94         err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
  95         if (err || !phys)
  96                 return -1;      /* beyond EOF or error */
  97 
  98         fat_dir_readahead(dir, iblock, phys);
  99 
 100         *bh = sb_bread(sb, phys);
 101         if (*bh == NULL) {
 102                 fat_msg_ratelimit(sb, KERN_ERR,
 103                         "Directory bread(block %llu) failed", (llu)phys);
 104                 /* skip this block */
 105                 *pos = (iblock + 1) << sb->s_blocksize_bits;
 106                 goto next;
 107         }
 108 
 109         offset = *pos & (sb->s_blocksize - 1);
 110         *pos += sizeof(struct msdos_dir_entry);
 111         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
 112 
 113         return 0;
 114 }
 115 
 116 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
 117                                 struct buffer_head **bh,
 118                                 struct msdos_dir_entry **de)
 119 {
 120         /* Fast stuff first */
 121         if (*bh && *de &&
 122            (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
 123                                 MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
 124                 *pos += sizeof(struct msdos_dir_entry);
 125                 (*de)++;
 126                 return 0;
 127         }
 128         return fat__get_entry(dir, pos, bh, de);
 129 }
 130 
 131 /*
 132  * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
 133  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
 134  * colon as an escape character since it is normally invalid on the vfat
 135  * filesystem. The following four characters are the hexadecimal digits
 136  * of Unicode value. This lets us do a full dump and restore of Unicode
 137  * filenames. We could get into some trouble with long Unicode names,
 138  * but ignore that right now.
 139  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
 140  */
 141 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
 142                        const wchar_t *uni, int len, struct nls_table *nls)
 143 {
 144         int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
 145         const wchar_t *ip;
 146         wchar_t ec;
 147         unsigned char *op;
 148         int charlen;
 149 
 150         ip = uni;
 151         op = ascii;
 152 
 153         while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
 154                 ec = *ip++;
 155                 charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
 156                 if (charlen > 0) {
 157                         op += charlen;
 158                         len -= charlen;
 159                 } else {
 160                         if (uni_xlate == 1) {
 161                                 *op++ = ':';
 162                                 op = hex_byte_pack(op, ec >> 8);
 163                                 op = hex_byte_pack(op, ec);
 164                                 len -= 5;
 165                         } else {
 166                                 *op++ = '?';
 167                                 len--;
 168                         }
 169                 }
 170         }
 171 
 172         if (unlikely(*ip)) {
 173                 fat_msg(sb, KERN_WARNING,
 174                         "filename was truncated while converting.");
 175         }
 176 
 177         *op = 0;
 178         return op - ascii;
 179 }
 180 
 181 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
 182                                 unsigned char *buf, int size)
 183 {
 184         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 185         if (sbi->options.utf8)
 186                 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
 187                                 UTF16_HOST_ENDIAN, buf, size);
 188         else
 189                 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
 190 }
 191 
 192 static inline int
 193 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 194 {
 195         int charlen;
 196 
 197         charlen = t->char2uni(c, clen, uni);
 198         if (charlen < 0) {
 199                 *uni = 0x003f;  /* a question mark */
 200                 charlen = 1;
 201         }
 202         return charlen;
 203 }
 204 
 205 static inline int
 206 fat_short2lower_uni(struct nls_table *t, unsigned char *c,
 207                     int clen, wchar_t *uni)
 208 {
 209         int charlen;
 210         wchar_t wc;
 211 
 212         charlen = t->char2uni(c, clen, &wc);
 213         if (charlen < 0) {
 214                 *uni = 0x003f;  /* a question mark */
 215                 charlen = 1;
 216         } else if (charlen <= 1) {
 217                 unsigned char nc = t->charset2lower[*c];
 218 
 219                 if (!nc)
 220                         nc = *c;
 221 
 222                 charlen = t->char2uni(&nc, 1, uni);
 223                 if (charlen < 0) {
 224                         *uni = 0x003f;  /* a question mark */
 225                         charlen = 1;
 226                 }
 227         } else
 228                 *uni = wc;
 229 
 230         return charlen;
 231 }
 232 
 233 static inline int
 234 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
 235                   wchar_t *uni_buf, unsigned short opt, int lower)
 236 {
 237         int len = 0;
 238 
 239         if (opt & VFAT_SFN_DISPLAY_LOWER)
 240                 len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 241         else if (opt & VFAT_SFN_DISPLAY_WIN95)
 242                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
 243         else if (opt & VFAT_SFN_DISPLAY_WINNT) {
 244                 if (lower)
 245                         len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 246                 else
 247                         len = fat_short2uni(nls, buf, buf_size, uni_buf);
 248         } else
 249                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
 250 
 251         return len;
 252 }
 253 
 254 static inline int fat_name_match(struct msdos_sb_info *sbi,
 255                                  const unsigned char *a, int a_len,
 256                                  const unsigned char *b, int b_len)
 257 {
 258         if (a_len != b_len)
 259                 return 0;
 260 
 261         if (sbi->options.name_check != 's')
 262                 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
 263         else
 264                 return !memcmp(a, b, a_len);
 265 }
 266 
 267 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
 268 
 269 /**
 270  * fat_parse_long - Parse extended directory entry.
 271  *
 272  * This function returns zero on success, negative value on error, or one of
 273  * the following:
 274  *
 275  * %PARSE_INVALID - Directory entry is invalid.
 276  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
 277  * %PARSE_EOF - Directory has no more entries.
 278  */
 279 static int fat_parse_long(struct inode *dir, loff_t *pos,
 280                           struct buffer_head **bh, struct msdos_dir_entry **de,
 281                           wchar_t **unicode, unsigned char *nr_slots)
 282 {
 283         struct msdos_dir_slot *ds;
 284         unsigned char id, slot, slots, alias_checksum;
 285 
 286         if (!*unicode) {
 287                 *unicode = __getname();
 288                 if (!*unicode) {
 289                         brelse(*bh);
 290                         return -ENOMEM;
 291                 }
 292         }
 293 parse_long:
 294         ds = (struct msdos_dir_slot *)*de;
 295         id = ds->id;
 296         if (!(id & 0x40))
 297                 return PARSE_INVALID;
 298         slots = id & ~0x40;
 299         if (slots > 20 || !slots)       /* ceil(256 * 2 / 26) */
 300                 return PARSE_INVALID;
 301         *nr_slots = slots;
 302         alias_checksum = ds->alias_checksum;
 303 
 304         slot = slots;
 305         while (1) {
 306                 int offset;
 307 
 308                 slot--;
 309                 offset = slot * 13;
 310                 fat16_towchar(*unicode + offset, ds->name0_4, 5);
 311                 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
 312                 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
 313 
 314                 if (ds->id & 0x40)
 315                         (*unicode)[offset + 13] = 0;
 316                 if (fat_get_entry(dir, pos, bh, de) < 0)
 317                         return PARSE_EOF;
 318                 if (slot == 0)
 319                         break;
 320                 ds = (struct msdos_dir_slot *)*de;
 321                 if (ds->attr != ATTR_EXT)
 322                         return PARSE_NOT_LONGNAME;
 323                 if ((ds->id & ~0x40) != slot)
 324                         goto parse_long;
 325                 if (ds->alias_checksum != alias_checksum)
 326                         goto parse_long;
 327         }
 328         if ((*de)->name[0] == DELETED_FLAG)
 329                 return PARSE_INVALID;
 330         if ((*de)->attr == ATTR_EXT)
 331                 goto parse_long;
 332         if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
 333                 return PARSE_INVALID;
 334         if (fat_checksum((*de)->name) != alias_checksum)
 335                 *nr_slots = 0;
 336 
 337         return 0;
 338 }
 339 
 340 /**
 341  * fat_parse_short - Parse MS-DOS (short) directory entry.
 342  * @sb:         superblock
 343  * @de:         directory entry to parse
 344  * @name:       FAT_MAX_SHORT_SIZE array in which to place extracted name
 345  * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN
 346  *
 347  * Returns the number of characters extracted into 'name'.
 348  */
 349 static int fat_parse_short(struct super_block *sb,
 350                            const struct msdos_dir_entry *de,
 351                            unsigned char *name, int dot_hidden)
 352 {
 353         const struct msdos_sb_info *sbi = MSDOS_SB(sb);
 354         int isvfat = sbi->options.isvfat;
 355         int nocase = sbi->options.nocase;
 356         unsigned short opt_shortname = sbi->options.shortname;
 357         struct nls_table *nls_disk = sbi->nls_disk;
 358         wchar_t uni_name[14];
 359         unsigned char c, work[MSDOS_NAME];
 360         unsigned char *ptname = name;
 361         int chi, chl, i, j, k;
 362         int dotoffset = 0;
 363         int name_len = 0, uni_len = 0;
 364 
 365         if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
 366                 *ptname++ = '.';
 367                 dotoffset = 1;
 368         }
 369 
 370         memcpy(work, de->name, sizeof(work));
 371         /* For an explanation of the special treatment of 0x05 in
 372          * filenames, see msdos_format_name in namei_msdos.c
 373          */
 374         if (work[0] == 0x05)
 375                 work[0] = 0xE5;
 376 
 377         /* Filename */
 378         for (i = 0, j = 0; i < 8;) {
 379                 c = work[i];
 380                 if (!c)
 381                         break;
 382                 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 383                                         &uni_name[j++], opt_shortname,
 384                                         de->lcase & CASE_LOWER_BASE);
 385                 if (chl <= 1) {
 386                         if (!isvfat)
 387                                 ptname[i] = nocase ? c : fat_tolower(c);
 388                         i++;
 389                         if (c != ' ') {
 390                                 name_len = i;
 391                                 uni_len  = j;
 392                         }
 393                 } else {
 394                         uni_len = j;
 395                         if (isvfat)
 396                                 i += min(chl, 8-i);
 397                         else {
 398                                 for (chi = 0; chi < chl && i < 8; chi++, i++)
 399                                         ptname[i] = work[i];
 400                         }
 401                         if (chl)
 402                                 name_len = i;
 403                 }
 404         }
 405 
 406         i = name_len;
 407         j = uni_len;
 408         fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
 409         if (!isvfat)
 410                 ptname[i] = '.';
 411         i++;
 412 
 413         /* Extension */
 414         for (k = 8; k < MSDOS_NAME;) {
 415                 c = work[k];
 416                 if (!c)
 417                         break;
 418                 chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
 419                                         &uni_name[j++], opt_shortname,
 420                                         de->lcase & CASE_LOWER_EXT);
 421                 if (chl <= 1) {
 422                         k++;
 423                         if (!isvfat)
 424                                 ptname[i] = nocase ? c : fat_tolower(c);
 425                         i++;
 426                         if (c != ' ') {
 427                                 name_len = i;
 428                                 uni_len  = j;
 429                         }
 430                 } else {
 431                         uni_len = j;
 432                         if (isvfat) {
 433                                 int offset = min(chl, MSDOS_NAME-k);
 434                                 k += offset;
 435                                 i += offset;
 436                         } else {
 437                                 for (chi = 0; chi < chl && k < MSDOS_NAME;
 438                                      chi++, i++, k++) {
 439                                                 ptname[i] = work[k];
 440                                 }
 441                         }
 442                         if (chl)
 443                                 name_len = i;
 444                 }
 445         }
 446 
 447         if (name_len > 0) {
 448                 name_len += dotoffset;
 449 
 450                 if (sbi->options.isvfat) {
 451                         uni_name[uni_len] = 0x0000;
 452                         name_len = fat_uni_to_x8(sb, uni_name, name,
 453                                                  FAT_MAX_SHORT_SIZE);
 454                 }
 455         }
 456 
 457         return name_len;
 458 }
 459 
 460 /*
 461  * Return values: negative -> error/not found, 0 -> found.
 462  */
 463 int fat_search_long(struct inode *inode, const unsigned char *name,
 464                     int name_len, struct fat_slot_info *sinfo)
 465 {
 466         struct super_block *sb = inode->i_sb;
 467         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 468         struct buffer_head *bh = NULL;
 469         struct msdos_dir_entry *de;
 470         unsigned char nr_slots;
 471         wchar_t *unicode = NULL;
 472         unsigned char bufname[FAT_MAX_SHORT_SIZE];
 473         loff_t cpos = 0;
 474         int err, len;
 475 
 476         err = -ENOENT;
 477         while (1) {
 478                 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 479                         goto end_of_dir;
 480 parse_record:
 481                 nr_slots = 0;
 482                 if (de->name[0] == DELETED_FLAG)
 483                         continue;
 484                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 485                         continue;
 486                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
 487                         continue;
 488                 if (de->attr == ATTR_EXT) {
 489                         int status = fat_parse_long(inode, &cpos, &bh, &de,
 490                                                     &unicode, &nr_slots);
 491                         if (status < 0) {
 492                                 err = status;
 493                                 goto end_of_dir;
 494                         } else if (status == PARSE_INVALID)
 495                                 continue;
 496                         else if (status == PARSE_NOT_LONGNAME)
 497                                 goto parse_record;
 498                         else if (status == PARSE_EOF)
 499                                 goto end_of_dir;
 500                 }
 501 
 502                 /* Never prepend '.' to hidden files here.
 503                  * That is done only for msdos mounts (and only when
 504                  * 'dotsOK=yes'); if we are executing here, it is in the
 505                  * context of a vfat mount.
 506                  */
 507                 len = fat_parse_short(sb, de, bufname, 0);
 508                 if (len == 0)
 509                         continue;
 510 
 511                 /* Compare shortname */
 512                 if (fat_name_match(sbi, name, name_len, bufname, len))
 513                         goto found;
 514 
 515                 if (nr_slots) {
 516                         void *longname = unicode + FAT_MAX_UNI_CHARS;
 517                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 518 
 519                         /* Compare longname */
 520                         len = fat_uni_to_x8(sb, unicode, longname, size);
 521                         if (fat_name_match(sbi, name, name_len, longname, len))
 522                                 goto found;
 523                 }
 524         }
 525 
 526 found:
 527         nr_slots++;     /* include the de */
 528         sinfo->slot_off = cpos - nr_slots * sizeof(*de);
 529         sinfo->nr_slots = nr_slots;
 530         sinfo->de = de;
 531         sinfo->bh = bh;
 532         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 533         err = 0;
 534 end_of_dir:
 535         if (unicode)
 536                 __putname(unicode);
 537 
 538         return err;
 539 }
 540 EXPORT_SYMBOL_GPL(fat_search_long);
 541 
 542 struct fat_ioctl_filldir_callback {
 543         struct dir_context ctx;
 544         void __user *dirent;
 545         int result;
 546         /* for dir ioctl */
 547         const char *longname;
 548         int long_len;
 549         const char *shortname;
 550         int short_len;
 551 };
 552 
 553 static int __fat_readdir(struct inode *inode, struct file *file,
 554                          struct dir_context *ctx, int short_only,
 555                          struct fat_ioctl_filldir_callback *both)
 556 {
 557         struct super_block *sb = inode->i_sb;
 558         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 559         struct buffer_head *bh;
 560         struct msdos_dir_entry *de;
 561         unsigned char nr_slots;
 562         wchar_t *unicode = NULL;
 563         unsigned char bufname[FAT_MAX_SHORT_SIZE];
 564         int isvfat = sbi->options.isvfat;
 565         const char *fill_name = NULL;
 566         int fake_offset = 0;
 567         loff_t cpos;
 568         int short_len = 0, fill_len = 0;
 569         int ret = 0;
 570 
 571         mutex_lock(&sbi->s_lock);
 572 
 573         cpos = ctx->pos;
 574         /* Fake . and .. for the root directory. */
 575         if (inode->i_ino == MSDOS_ROOT_INO) {
 576                 if (!dir_emit_dots(file, ctx))
 577                         goto out;
 578                 if (ctx->pos == 2) {
 579                         fake_offset = 1;
 580                         cpos = 0;
 581                 }
 582         }
 583         if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
 584                 ret = -ENOENT;
 585                 goto out;
 586         }
 587 
 588         bh = NULL;
 589 get_new:
 590         if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 591                 goto end_of_dir;
 592 parse_record:
 593         nr_slots = 0;
 594         /*
 595          * Check for long filename entry, but if short_only, we don't
 596          * need to parse long filename.
 597          */
 598         if (isvfat && !short_only) {
 599                 if (de->name[0] == DELETED_FLAG)
 600                         goto record_end;
 601                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 602                         goto record_end;
 603                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
 604                         goto record_end;
 605         } else {
 606                 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
 607                         goto record_end;
 608         }
 609 
 610         if (isvfat && de->attr == ATTR_EXT) {
 611                 int status = fat_parse_long(inode, &cpos, &bh, &de,
 612                                             &unicode, &nr_slots);
 613                 if (status < 0) {
 614                         bh = NULL;
 615                         ret = status;
 616                         goto end_of_dir;
 617                 } else if (status == PARSE_INVALID)
 618                         goto record_end;
 619                 else if (status == PARSE_NOT_LONGNAME)
 620                         goto parse_record;
 621                 else if (status == PARSE_EOF)
 622                         goto end_of_dir;
 623 
 624                 if (nr_slots) {
 625                         void *longname = unicode + FAT_MAX_UNI_CHARS;
 626                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 627                         int len = fat_uni_to_x8(sb, unicode, longname, size);
 628 
 629                         fill_name = longname;
 630                         fill_len = len;
 631                         /* !both && !short_only, so we don't need shortname. */
 632                         if (!both)
 633                                 goto start_filldir;
 634 
 635                         short_len = fat_parse_short(sb, de, bufname,
 636                                                     sbi->options.dotsOK);
 637                         if (short_len == 0)
 638                                 goto record_end;
 639                         /* hack for fat_ioctl_filldir() */
 640                         both->longname = fill_name;
 641                         both->long_len = fill_len;
 642                         both->shortname = bufname;
 643                         both->short_len = short_len;
 644                         fill_name = NULL;
 645                         fill_len = 0;
 646                         goto start_filldir;
 647                 }
 648         }
 649 
 650         short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
 651         if (short_len == 0)
 652                 goto record_end;
 653 
 654         fill_name = bufname;
 655         fill_len = short_len;
 656 
 657 start_filldir:
 658         ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
 659         if (fake_offset && ctx->pos < 2)
 660                 ctx->pos = 2;
 661 
 662         if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
 663                 if (!dir_emit_dot(file, ctx))
 664                         goto fill_failed;
 665         } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 666                 if (!dir_emit_dotdot(file, ctx))
 667                         goto fill_failed;
 668         } else {
 669                 unsigned long inum;
 670                 loff_t i_pos = fat_make_i_pos(sb, bh, de);
 671                 struct inode *tmp = fat_iget(sb, i_pos);
 672                 if (tmp) {
 673                         inum = tmp->i_ino;
 674                         iput(tmp);
 675                 } else
 676                         inum = iunique(sb, MSDOS_ROOT_INO);
 677                 if (!dir_emit(ctx, fill_name, fill_len, inum,
 678                             (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
 679                         goto fill_failed;
 680         }
 681 
 682 record_end:
 683         fake_offset = 0;
 684         ctx->pos = cpos;
 685         goto get_new;
 686 
 687 end_of_dir:
 688         if (fake_offset && cpos < 2)
 689                 ctx->pos = 2;
 690         else
 691                 ctx->pos = cpos;
 692 fill_failed:
 693         brelse(bh);
 694         if (unicode)
 695                 __putname(unicode);
 696 out:
 697         mutex_unlock(&sbi->s_lock);
 698 
 699         return ret;
 700 }
 701 
 702 static int fat_readdir(struct file *file, struct dir_context *ctx)
 703 {
 704         return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
 705 }
 706 
 707 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)                          \
 708 static int func(struct dir_context *ctx, const char *name, int name_len,   \
 709                              loff_t offset, u64 ino, unsigned int d_type)  \
 710 {                                                                          \
 711         struct fat_ioctl_filldir_callback *buf =                           \
 712                 container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
 713         struct dirent_type __user *d1 = buf->dirent;                       \
 714         struct dirent_type __user *d2 = d1 + 1;                            \
 715                                                                            \
 716         if (buf->result)                                                   \
 717                 return -EINVAL;                                            \
 718         buf->result++;                                                     \
 719                                                                            \
 720         if (name != NULL) {                                                \
 721                 /* dirent has only short name */                           \
 722                 if (name_len >= sizeof(d1->d_name))                        \
 723                         name_len = sizeof(d1->d_name) - 1;                 \
 724                                                                            \
 725                 if (put_user(0, d2->d_name)                     ||         \
 726                     put_user(0, &d2->d_reclen)                  ||         \
 727                     copy_to_user(d1->d_name, name, name_len)    ||         \
 728                     put_user(0, d1->d_name + name_len)          ||         \
 729                     put_user(name_len, &d1->d_reclen))                     \
 730                         goto efault;                                       \
 731         } else {                                                           \
 732                 /* dirent has short and long name */                       \
 733                 const char *longname = buf->longname;                      \
 734                 int long_len = buf->long_len;                              \
 735                 const char *shortname = buf->shortname;                    \
 736                 int short_len = buf->short_len;                            \
 737                                                                            \
 738                 if (long_len >= sizeof(d1->d_name))                        \
 739                         long_len = sizeof(d1->d_name) - 1;                 \
 740                 if (short_len >= sizeof(d1->d_name))                       \
 741                         short_len = sizeof(d1->d_name) - 1;                \
 742                                                                            \
 743                 if (copy_to_user(d2->d_name, longname, long_len)        || \
 744                     put_user(0, d2->d_name + long_len)                  || \
 745                     put_user(long_len, &d2->d_reclen)                   || \
 746                     put_user(ino, &d2->d_ino)                           || \
 747                     put_user(offset, &d2->d_off)                        || \
 748                     copy_to_user(d1->d_name, shortname, short_len)      || \
 749                     put_user(0, d1->d_name + short_len)                 || \
 750                     put_user(short_len, &d1->d_reclen))                    \
 751                         goto efault;                                       \
 752         }                                                                  \
 753         return 0;                                                          \
 754 efault:                                                                    \
 755         buf->result = -EFAULT;                                             \
 756         return -EFAULT;                                                    \
 757 }
 758 
 759 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
 760 
 761 static int fat_ioctl_readdir(struct inode *inode, struct file *file,
 762                              void __user *dirent, filldir_t filldir,
 763                              int short_only, int both)
 764 {
 765         struct fat_ioctl_filldir_callback buf = {
 766                 .ctx.actor = filldir,
 767                 .dirent = dirent
 768         };
 769         int ret;
 770 
 771         buf.dirent = dirent;
 772         buf.result = 0;
 773         inode_lock_shared(inode);
 774         buf.ctx.pos = file->f_pos;
 775         ret = -ENOENT;
 776         if (!IS_DEADDIR(inode)) {
 777                 ret = __fat_readdir(inode, file, &buf.ctx,
 778                                     short_only, both ? &buf : NULL);
 779                 file->f_pos = buf.ctx.pos;
 780         }
 781         inode_unlock_shared(inode);
 782         if (ret >= 0)
 783                 ret = buf.result;
 784         return ret;
 785 }
 786 
 787 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
 788                           unsigned long arg)
 789 {
 790         struct inode *inode = file_inode(filp);
 791         struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
 792         int short_only, both;
 793 
 794         switch (cmd) {
 795         case VFAT_IOCTL_READDIR_SHORT:
 796                 short_only = 1;
 797                 both = 0;
 798                 break;
 799         case VFAT_IOCTL_READDIR_BOTH:
 800                 short_only = 0;
 801                 both = 1;
 802                 break;
 803         default:
 804                 return fat_generic_ioctl(filp, cmd, arg);
 805         }
 806 
 807         if (!access_ok(d1, sizeof(struct __fat_dirent[2])))
 808                 return -EFAULT;
 809         /*
 810          * Yes, we don't need this put_user() absolutely. However old
 811          * code didn't return the right value. So, app use this value,
 812          * in order to check whether it is EOF.
 813          */
 814         if (put_user(0, &d1->d_reclen))
 815                 return -EFAULT;
 816 
 817         return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
 818                                  short_only, both);
 819 }
 820 
 821 #ifdef CONFIG_COMPAT
 822 #define VFAT_IOCTL_READDIR_BOTH32       _IOR('r', 1, struct compat_dirent[2])
 823 #define VFAT_IOCTL_READDIR_SHORT32      _IOR('r', 2, struct compat_dirent[2])
 824 
 825 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
 826 
 827 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
 828                                  unsigned long arg)
 829 {
 830         struct inode *inode = file_inode(filp);
 831         struct compat_dirent __user *d1 = compat_ptr(arg);
 832         int short_only, both;
 833 
 834         switch (cmd) {
 835         case VFAT_IOCTL_READDIR_SHORT32:
 836                 short_only = 1;
 837                 both = 0;
 838                 break;
 839         case VFAT_IOCTL_READDIR_BOTH32:
 840                 short_only = 0;
 841                 both = 1;
 842                 break;
 843         default:
 844                 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
 845         }
 846 
 847         if (!access_ok(d1, sizeof(struct compat_dirent[2])))
 848                 return -EFAULT;
 849         /*
 850          * Yes, we don't need this put_user() absolutely. However old
 851          * code didn't return the right value. So, app use this value,
 852          * in order to check whether it is EOF.
 853          */
 854         if (put_user(0, &d1->d_reclen))
 855                 return -EFAULT;
 856 
 857         return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
 858                                  short_only, both);
 859 }
 860 #endif /* CONFIG_COMPAT */
 861 
 862 const struct file_operations fat_dir_operations = {
 863         .llseek         = generic_file_llseek,
 864         .read           = generic_read_dir,
 865         .iterate_shared = fat_readdir,
 866         .unlocked_ioctl = fat_dir_ioctl,
 867 #ifdef CONFIG_COMPAT
 868         .compat_ioctl   = fat_compat_dir_ioctl,
 869 #endif
 870         .fsync          = fat_file_fsync,
 871 };
 872 
 873 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 874                                struct buffer_head **bh,
 875                                struct msdos_dir_entry **de)
 876 {
 877         while (fat_get_entry(dir, pos, bh, de) >= 0) {
 878                 /* free entry or long name entry or volume label */
 879                 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
 880                         return 0;
 881         }
 882         return -ENOENT;
 883 }
 884 
 885 /*
 886  * The ".." entry can not provide the "struct fat_slot_info" information
 887  * for inode, nor a usable i_pos. So, this function provides some information
 888  * only.
 889  *
 890  * Since this function walks through the on-disk inodes within a directory,
 891  * callers are responsible for taking any locks necessary to prevent the
 892  * directory from changing.
 893  */
 894 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 895                          struct msdos_dir_entry **de)
 896 {
 897         loff_t offset = 0;
 898 
 899         *de = NULL;
 900         while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
 901                 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
 902                         return 0;
 903         }
 904         return -ENOENT;
 905 }
 906 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 907 
 908 /* See if directory is empty */
 909 int fat_dir_empty(struct inode *dir)
 910 {
 911         struct buffer_head *bh;
 912         struct msdos_dir_entry *de;
 913         loff_t cpos;
 914         int result = 0;
 915 
 916         bh = NULL;
 917         cpos = 0;
 918         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 919                 if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
 920                     strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 921                         result = -ENOTEMPTY;
 922                         break;
 923                 }
 924         }
 925         brelse(bh);
 926         return result;
 927 }
 928 EXPORT_SYMBOL_GPL(fat_dir_empty);
 929 
 930 /*
 931  * fat_subdirs counts the number of sub-directories of dir. It can be run
 932  * on directories being created.
 933  */
 934 int fat_subdirs(struct inode *dir)
 935 {
 936         struct buffer_head *bh;
 937         struct msdos_dir_entry *de;
 938         loff_t cpos;
 939         int count = 0;
 940 
 941         bh = NULL;
 942         cpos = 0;
 943         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 944                 if (de->attr & ATTR_DIR)
 945                         count++;
 946         }
 947         brelse(bh);
 948         return count;
 949 }
 950 
 951 /*
 952  * Scans a directory for a given file (name points to its formatted name).
 953  * Returns an error code or zero.
 954  */
 955 int fat_scan(struct inode *dir, const unsigned char *name,
 956              struct fat_slot_info *sinfo)
 957 {
 958         struct super_block *sb = dir->i_sb;
 959 
 960         sinfo->slot_off = 0;
 961         sinfo->bh = NULL;
 962         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 963                                    &sinfo->de) >= 0) {
 964                 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
 965                         sinfo->slot_off -= sizeof(*sinfo->de);
 966                         sinfo->nr_slots = 1;
 967                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 968                         return 0;
 969                 }
 970         }
 971         return -ENOENT;
 972 }
 973 EXPORT_SYMBOL_GPL(fat_scan);
 974 
 975 /*
 976  * Scans a directory for a given logstart.
 977  * Returns an error code or zero.
 978  */
 979 int fat_scan_logstart(struct inode *dir, int i_logstart,
 980                       struct fat_slot_info *sinfo)
 981 {
 982         struct super_block *sb = dir->i_sb;
 983 
 984         sinfo->slot_off = 0;
 985         sinfo->bh = NULL;
 986         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 987                                    &sinfo->de) >= 0) {
 988                 if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
 989                         sinfo->slot_off -= sizeof(*sinfo->de);
 990                         sinfo->nr_slots = 1;
 991                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 992                         return 0;
 993                 }
 994         }
 995         return -ENOENT;
 996 }
 997 
 998 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
 999 {
1000         struct super_block *sb = dir->i_sb;
1001         struct buffer_head *bh;
1002         struct msdos_dir_entry *de, *endp;
1003         int err = 0, orig_slots;
1004 
1005         while (nr_slots) {
1006                 bh = NULL;
1007                 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
1008                         err = -EIO;
1009                         break;
1010                 }
1011 
1012                 orig_slots = nr_slots;
1013                 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
1014                 while (nr_slots && de < endp) {
1015                         de->name[0] = DELETED_FLAG;
1016                         de++;
1017                         nr_slots--;
1018                 }
1019                 mark_buffer_dirty_inode(bh, dir);
1020                 if (IS_DIRSYNC(dir))
1021                         err = sync_dirty_buffer(bh);
1022                 brelse(bh);
1023                 if (err)
1024                         break;
1025 
1026                 /* pos is *next* de's position, so this does `- sizeof(de)' */
1027                 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
1028         }
1029 
1030         return err;
1031 }
1032 
1033 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1034 {
1035         struct super_block *sb = dir->i_sb;
1036         struct msdos_dir_entry *de;
1037         struct buffer_head *bh;
1038         int err = 0, nr_slots;
1039 
1040         /*
1041          * First stage: Remove the shortname. By this, the directory
1042          * entry is removed.
1043          */
1044         nr_slots = sinfo->nr_slots;
1045         de = sinfo->de;
1046         sinfo->de = NULL;
1047         bh = sinfo->bh;
1048         sinfo->bh = NULL;
1049         while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1050                 de->name[0] = DELETED_FLAG;
1051                 de--;
1052                 nr_slots--;
1053         }
1054         mark_buffer_dirty_inode(bh, dir);
1055         if (IS_DIRSYNC(dir))
1056                 err = sync_dirty_buffer(bh);
1057         brelse(bh);
1058         if (err)
1059                 return err;
1060         inode_inc_iversion(dir);
1061 
1062         if (nr_slots) {
1063                 /*
1064                  * Second stage: remove the remaining longname slots.
1065                  * (This directory entry is already removed, and so return
1066                  * the success)
1067                  */
1068                 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1069                 if (err) {
1070                         fat_msg(sb, KERN_WARNING,
1071                                "Couldn't remove the long name slots");
1072                 }
1073         }
1074 
1075         fat_truncate_time(dir, NULL, S_ATIME|S_MTIME);
1076         if (IS_DIRSYNC(dir))
1077                 (void)fat_sync_inode(dir);
1078         else
1079                 mark_inode_dirty(dir);
1080 
1081         return 0;
1082 }
1083 EXPORT_SYMBOL_GPL(fat_remove_entries);
1084 
1085 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1086                               struct buffer_head **bhs, int nr_bhs)
1087 {
1088         struct super_block *sb = dir->i_sb;
1089         sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1090         int err, i, n;
1091 
1092         /* Zeroing the unused blocks on this cluster */
1093         blknr += nr_used;
1094         n = nr_used;
1095         while (blknr < last_blknr) {
1096                 bhs[n] = sb_getblk(sb, blknr);
1097                 if (!bhs[n]) {
1098                         err = -ENOMEM;
1099                         goto error;
1100                 }
1101                 /* Avoid race with userspace read via bdev */
1102                 lock_buffer(bhs[n]);
1103                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1104                 set_buffer_uptodate(bhs[n]);
1105                 unlock_buffer(bhs[n]);
1106                 mark_buffer_dirty_inode(bhs[n], dir);
1107 
1108                 n++;
1109                 blknr++;
1110                 if (n == nr_bhs) {
1111                         if (IS_DIRSYNC(dir)) {
1112                                 err = fat_sync_bhs(bhs, n);
1113                                 if (err)
1114                                         goto error;
1115                         }
1116                         for (i = 0; i < n; i++)
1117                                 brelse(bhs[i]);
1118                         n = 0;
1119                 }
1120         }
1121         if (IS_DIRSYNC(dir)) {
1122                 err = fat_sync_bhs(bhs, n);
1123                 if (err)
1124                         goto error;
1125         }
1126         for (i = 0; i < n; i++)
1127                 brelse(bhs[i]);
1128 
1129         return 0;
1130 
1131 error:
1132         for (i = 0; i < n; i++)
1133                 bforget(bhs[i]);
1134         return err;
1135 }
1136 
1137 int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
1138 {
1139         struct super_block *sb = dir->i_sb;
1140         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1141         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1142         struct msdos_dir_entry *de;
1143         sector_t blknr;
1144         __le16 date, time;
1145         u8 time_cs;
1146         int err, cluster;
1147 
1148         err = fat_alloc_clusters(dir, &cluster, 1);
1149         if (err)
1150                 goto error;
1151 
1152         blknr = fat_clus_to_blknr(sbi, cluster);
1153         bhs[0] = sb_getblk(sb, blknr);
1154         if (!bhs[0]) {
1155                 err = -ENOMEM;
1156                 goto error_free;
1157         }
1158 
1159         fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1160 
1161         de = (struct msdos_dir_entry *)bhs[0]->b_data;
1162         /* Avoid race with userspace read via bdev */
1163         lock_buffer(bhs[0]);
1164         /* filling the new directory slots ("." and ".." entries) */
1165         memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1166         memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1167         de->attr = de[1].attr = ATTR_DIR;
1168         de[0].lcase = de[1].lcase = 0;
1169         de[0].time = de[1].time = time;
1170         de[0].date = de[1].date = date;
1171         if (sbi->options.isvfat) {
1172                 /* extra timestamps */
1173                 de[0].ctime = de[1].ctime = time;
1174                 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1175                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1176         } else {
1177                 de[0].ctime = de[1].ctime = 0;
1178                 de[0].ctime_cs = de[1].ctime_cs = 0;
1179                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1180         }
1181         fat_set_start(&de[0], cluster);
1182         fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1183         de[0].size = de[1].size = 0;
1184         memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1185         set_buffer_uptodate(bhs[0]);
1186         unlock_buffer(bhs[0]);
1187         mark_buffer_dirty_inode(bhs[0], dir);
1188 
1189         err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1190         if (err)
1191                 goto error_free;
1192 
1193         return cluster;
1194 
1195 error_free:
1196         fat_free_clusters(dir, cluster);
1197 error:
1198         return err;
1199 }
1200 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1201 
1202 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1203                                int *nr_cluster, struct msdos_dir_entry **de,
1204                                struct buffer_head **bh, loff_t *i_pos)
1205 {
1206         struct super_block *sb = dir->i_sb;
1207         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1208         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1209         sector_t blknr, start_blknr, last_blknr;
1210         unsigned long size, copy;
1211         int err, i, n, offset, cluster[2];
1212 
1213         /*
1214          * The minimum cluster size is 512bytes, and maximum entry
1215          * size is 32*slots (672bytes).  So, iff the cluster size is
1216          * 512bytes, we may need two clusters.
1217          */
1218         size = nr_slots * sizeof(struct msdos_dir_entry);
1219         *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1220         BUG_ON(*nr_cluster > 2);
1221 
1222         err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1223         if (err)
1224                 goto error;
1225 
1226         /*
1227          * First stage: Fill the directory entry.  NOTE: This cluster
1228          * is not referenced from any inode yet, so updates order is
1229          * not important.
1230          */
1231         i = n = copy = 0;
1232         do {
1233                 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1234                 last_blknr = start_blknr + sbi->sec_per_clus;
1235                 while (blknr < last_blknr) {
1236                         bhs[n] = sb_getblk(sb, blknr);
1237                         if (!bhs[n]) {
1238                                 err = -ENOMEM;
1239                                 goto error_nomem;
1240                         }
1241 
1242                         /* fill the directory entry */
1243                         copy = min(size, sb->s_blocksize);
1244                         /* Avoid race with userspace read via bdev */
1245                         lock_buffer(bhs[n]);
1246                         memcpy(bhs[n]->b_data, slots, copy);
1247                         set_buffer_uptodate(bhs[n]);
1248                         unlock_buffer(bhs[n]);
1249                         mark_buffer_dirty_inode(bhs[n], dir);
1250                         slots += copy;
1251                         size -= copy;
1252                         if (!size)
1253                                 break;
1254                         n++;
1255                         blknr++;
1256                 }
1257         } while (++i < *nr_cluster);
1258 
1259         memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1260         offset = copy - sizeof(struct msdos_dir_entry);
1261         get_bh(bhs[n]);
1262         *bh = bhs[n];
1263         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1264         *i_pos = fat_make_i_pos(sb, *bh, *de);
1265 
1266         /* Second stage: clear the rest of cluster, and write outs */
1267         err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1268         if (err)
1269                 goto error_free;
1270 
1271         return cluster[0];
1272 
1273 error_free:
1274         brelse(*bh);
1275         *bh = NULL;
1276         n = 0;
1277 error_nomem:
1278         for (i = 0; i < n; i++)
1279                 bforget(bhs[i]);
1280         fat_free_clusters(dir, cluster[0]);
1281 error:
1282         return err;
1283 }
1284 
1285 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1286                     struct fat_slot_info *sinfo)
1287 {
1288         struct super_block *sb = dir->i_sb;
1289         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1290         struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1291         struct msdos_dir_entry *uninitialized_var(de);
1292         int err, free_slots, i, nr_bhs;
1293         loff_t pos, i_pos;
1294 
1295         sinfo->nr_slots = nr_slots;
1296 
1297         /* First stage: search free directory entries */
1298         free_slots = nr_bhs = 0;
1299         bh = prev = NULL;
1300         pos = 0;
1301         err = -ENOSPC;
1302         while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1303                 /* check the maximum size of directory */
1304                 if (pos >= FAT_MAX_DIR_SIZE)
1305                         goto error;
1306 
1307                 if (IS_FREE(de->name)) {
1308                         if (prev != bh) {
1309                                 get_bh(bh);
1310                                 bhs[nr_bhs] = prev = bh;
1311                                 nr_bhs++;
1312                         }
1313                         free_slots++;
1314                         if (free_slots == nr_slots)
1315                                 goto found;
1316                 } else {
1317                         for (i = 0; i < nr_bhs; i++)
1318                                 brelse(bhs[i]);
1319                         prev = NULL;
1320                         free_slots = nr_bhs = 0;
1321                 }
1322         }
1323         if (dir->i_ino == MSDOS_ROOT_INO) {
1324                 if (!is_fat32(sbi))
1325                         goto error;
1326         } else if (MSDOS_I(dir)->i_start == 0) {
1327                 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1328                        MSDOS_I(dir)->i_pos);
1329                 err = -EIO;
1330                 goto error;
1331         }
1332 
1333 found:
1334         err = 0;
1335         pos -= free_slots * sizeof(*de);
1336         nr_slots -= free_slots;
1337         if (free_slots) {
1338                 /*
1339                  * Second stage: filling the free entries with new entries.
1340                  * NOTE: If this slots has shortname, first, we write
1341                  * the long name slots, then write the short name.
1342                  */
1343                 int size = free_slots * sizeof(*de);
1344                 int offset = pos & (sb->s_blocksize - 1);
1345                 int long_bhs = nr_bhs - (nr_slots == 0);
1346 
1347                 /* Fill the long name slots. */
1348                 for (i = 0; i < long_bhs; i++) {
1349                         int copy = min_t(int, sb->s_blocksize - offset, size);
1350                         memcpy(bhs[i]->b_data + offset, slots, copy);
1351                         mark_buffer_dirty_inode(bhs[i], dir);
1352                         offset = 0;
1353                         slots += copy;
1354                         size -= copy;
1355                 }
1356                 if (long_bhs && IS_DIRSYNC(dir))
1357                         err = fat_sync_bhs(bhs, long_bhs);
1358                 if (!err && i < nr_bhs) {
1359                         /* Fill the short name slot. */
1360                         int copy = min_t(int, sb->s_blocksize - offset, size);
1361                         memcpy(bhs[i]->b_data + offset, slots, copy);
1362                         mark_buffer_dirty_inode(bhs[i], dir);
1363                         if (IS_DIRSYNC(dir))
1364                                 err = sync_dirty_buffer(bhs[i]);
1365                 }
1366                 for (i = 0; i < nr_bhs; i++)
1367                         brelse(bhs[i]);
1368                 if (err)
1369                         goto error_remove;
1370         }
1371 
1372         if (nr_slots) {
1373                 int cluster, nr_cluster;
1374 
1375                 /*
1376                  * Third stage: allocate the cluster for new entries.
1377                  * And initialize the cluster with new entries, then
1378                  * add the cluster to dir.
1379                  */
1380                 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1381                                               &de, &bh, &i_pos);
1382                 if (cluster < 0) {
1383                         err = cluster;
1384                         goto error_remove;
1385                 }
1386                 err = fat_chain_add(dir, cluster, nr_cluster);
1387                 if (err) {
1388                         fat_free_clusters(dir, cluster);
1389                         goto error_remove;
1390                 }
1391                 if (dir->i_size & (sbi->cluster_size - 1)) {
1392                         fat_fs_error(sb, "Odd directory size");
1393                         dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1394                                 & ~((loff_t)sbi->cluster_size - 1);
1395                 }
1396                 dir->i_size += nr_cluster << sbi->cluster_bits;
1397                 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1398         }
1399         sinfo->slot_off = pos;
1400         sinfo->de = de;
1401         sinfo->bh = bh;
1402         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1403 
1404         return 0;
1405 
1406 error:
1407         brelse(bh);
1408         for (i = 0; i < nr_bhs; i++)
1409                 brelse(bhs[i]);
1410         return err;
1411 
1412 error_remove:
1413         brelse(bh);
1414         if (free_slots)
1415                 __fat_remove_entries(dir, pos, free_slots);
1416         return err;
1417 }
1418 EXPORT_SYMBOL_GPL(fat_add_entries);
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root/fs/fat/dir.c

DEFINITIONS
