linux/fs/fat/namei_vfat.c
<<
>>
Prefs
   1/*
   2 *  linux/fs/vfat/namei.c
   3 *
   4 *  Written 1992,1993 by Werner Almesberger
   5 *
   6 *  Windows95/Windows NT compatible extended MSDOS filesystem
   7 *    by Gordon Chaffee Copyright (C) 1995.  Send bug reports for the
   8 *    VFAT filesystem to <chaffee@cs.berkeley.edu>.  Specify
   9 *    what file operation caused you trouble and if you can duplicate
  10 *    the problem, send a script that demonstrates it.
  11 *
  12 *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
  13 *
  14 *  Support Multibyte characters and cleanup by
  15 *                              OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
  16 */
  17
  18#include <linux/module.h>
  19#include <linux/jiffies.h>
  20#include <linux/ctype.h>
  21#include <linux/slab.h>
  22#include <linux/buffer_head.h>
  23#include <linux/namei.h>
  24#include "fat.h"
  25
  26/*
  27 * If new entry was created in the parent, it could create the 8.3
  28 * alias (the shortname of logname).  So, the parent may have the
  29 * negative-dentry which matches the created 8.3 alias.
  30 *
  31 * If it happened, the negative dentry isn't actually negative
  32 * anymore.  So, drop it.
  33 */
  34static int vfat_revalidate_shortname(struct dentry *dentry)
  35{
  36        int ret = 1;
  37        spin_lock(&dentry->d_lock);
  38        if (dentry->d_time != dentry->d_parent->d_inode->i_version)
  39                ret = 0;
  40        spin_unlock(&dentry->d_lock);
  41        return ret;
  42}
  43
  44static int vfat_revalidate(struct dentry *dentry, unsigned int flags)
  45{
  46        if (flags & LOOKUP_RCU)
  47                return -ECHILD;
  48
  49        /* This is not negative dentry. Always valid. */
  50        if (dentry->d_inode)
  51                return 1;
  52        return vfat_revalidate_shortname(dentry);
  53}
  54
  55static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags)
  56{
  57        if (flags & LOOKUP_RCU)
  58                return -ECHILD;
  59
  60        /*
  61         * This is not negative dentry. Always valid.
  62         *
  63         * Note, rename() to existing directory entry will have ->d_inode,
  64         * and will use existing name which isn't specified name by user.
  65         *
  66         * We may be able to drop this positive dentry here. But dropping
  67         * positive dentry isn't good idea. So it's unsupported like
  68         * rename("filename", "FILENAME") for now.
  69         */
  70        if (dentry->d_inode)
  71                return 1;
  72
  73        /*
  74         * This may be nfsd (or something), anyway, we can't see the
  75         * intent of this. So, since this can be for creation, drop it.
  76         */
  77        if (!flags)
  78                return 0;
  79
  80        /*
  81         * Drop the negative dentry, in order to make sure to use the
  82         * case sensitive name which is specified by user if this is
  83         * for creation.
  84         */
  85        if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
  86                return 0;
  87
  88        return vfat_revalidate_shortname(dentry);
  89}
  90
  91/* returns the length of a struct qstr, ignoring trailing dots */
  92static unsigned int __vfat_striptail_len(unsigned int len, const char *name)
  93{
  94        while (len && name[len - 1] == '.')
  95                len--;
  96        return len;
  97}
  98
  99static unsigned int vfat_striptail_len(const struct qstr *qstr)
 100{
 101        return __vfat_striptail_len(qstr->len, qstr->name);
 102}
 103
 104/*
 105 * Compute the hash for the vfat name corresponding to the dentry.
 106 * Note: if the name is invalid, we leave the hash code unchanged so
 107 * that the existing dentry can be used. The vfat fs routines will
 108 * return ENOENT or EINVAL as appropriate.
 109 */
 110static int vfat_hash(const struct dentry *dentry, const struct inode *inode,
 111                struct qstr *qstr)
 112{
 113        qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
 114        return 0;
 115}
 116
 117/*
 118 * Compute the hash for the vfat name corresponding to the dentry.
 119 * Note: if the name is invalid, we leave the hash code unchanged so
 120 * that the existing dentry can be used. The vfat fs routines will
 121 * return ENOENT or EINVAL as appropriate.
 122 */
 123static int vfat_hashi(const struct dentry *dentry, const struct inode *inode,
 124                struct qstr *qstr)
 125{
 126        struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io;
 127        const unsigned char *name;
 128        unsigned int len;
 129        unsigned long hash;
 130
 131        name = qstr->name;
 132        len = vfat_striptail_len(qstr);
 133
 134        hash = init_name_hash();
 135        while (len--)
 136                hash = partial_name_hash(nls_tolower(t, *name++), hash);
 137        qstr->hash = end_name_hash(hash);
 138
 139        return 0;
 140}
 141
 142/*
 143 * Case insensitive compare of two vfat names.
 144 */
 145static int vfat_cmpi(const struct dentry *parent, const struct inode *pinode,
 146                const struct dentry *dentry, const struct inode *inode,
 147                unsigned int len, const char *str, const struct qstr *name)
 148{
 149        struct nls_table *t = MSDOS_SB(parent->d_sb)->nls_io;
 150        unsigned int alen, blen;
 151
 152        /* A filename cannot end in '.' or we treat it like it has none */
 153        alen = vfat_striptail_len(name);
 154        blen = __vfat_striptail_len(len, str);
 155        if (alen == blen) {
 156                if (nls_strnicmp(t, name->name, str, alen) == 0)
 157                        return 0;
 158        }
 159        return 1;
 160}
 161
 162/*
 163 * Case sensitive compare of two vfat names.
 164 */
 165static int vfat_cmp(const struct dentry *parent, const struct inode *pinode,
 166                const struct dentry *dentry, const struct inode *inode,
 167                unsigned int len, const char *str, const struct qstr *name)
 168{
 169        unsigned int alen, blen;
 170
 171        /* A filename cannot end in '.' or we treat it like it has none */
 172        alen = vfat_striptail_len(name);
 173        blen = __vfat_striptail_len(len, str);
 174        if (alen == blen) {
 175                if (strncmp(name->name, str, alen) == 0)
 176                        return 0;
 177        }
 178        return 1;
 179}
 180
 181static const struct dentry_operations vfat_ci_dentry_ops = {
 182        .d_revalidate   = vfat_revalidate_ci,
 183        .d_hash         = vfat_hashi,
 184        .d_compare      = vfat_cmpi,
 185};
 186
 187static const struct dentry_operations vfat_dentry_ops = {
 188        .d_revalidate   = vfat_revalidate,
 189        .d_hash         = vfat_hash,
 190        .d_compare      = vfat_cmp,
 191};
 192
 193/* Characters that are undesirable in an MS-DOS file name */
 194
 195static inline wchar_t vfat_bad_char(wchar_t w)
 196{
 197        return (w < 0x0020)
 198            || (w == '*') || (w == '?') || (w == '<') || (w == '>')
 199            || (w == '|') || (w == '"') || (w == ':') || (w == '/')
 200            || (w == '\\');
 201}
 202
 203static inline wchar_t vfat_replace_char(wchar_t w)
 204{
 205        return (w == '[') || (w == ']') || (w == ';') || (w == ',')
 206            || (w == '+') || (w == '=');
 207}
 208
 209static wchar_t vfat_skip_char(wchar_t w)
 210{
 211        return (w == '.') || (w == ' ');
 212}
 213
 214static inline int vfat_is_used_badchars(const wchar_t *s, int len)
 215{
 216        int i;
 217
 218        for (i = 0; i < len; i++)
 219                if (vfat_bad_char(s[i]))
 220                        return -EINVAL;
 221
 222        if (s[i - 1] == ' ') /* last character cannot be space */
 223                return -EINVAL;
 224
 225        return 0;
 226}
 227
 228static int vfat_find_form(struct inode *dir, unsigned char *name)
 229{
 230        struct fat_slot_info sinfo;
 231        int err = fat_scan(dir, name, &sinfo);
 232        if (err)
 233                return -ENOENT;
 234        brelse(sinfo.bh);
 235        return 0;
 236}
 237
 238/*
 239 * 1) Valid characters for the 8.3 format alias are any combination of
 240 * letters, uppercase alphabets, digits, any of the
 241 * following special characters:
 242 *     $ % ' ` - @ { } ~ ! # ( ) & _ ^
 243 * In this case Longfilename is not stored in disk.
 244 *
 245 * WinNT's Extension:
 246 * File name and extension name is contain uppercase/lowercase
 247 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
 248 *
 249 * 2) File name is 8.3 format, but it contain the uppercase and
 250 * lowercase char, muliti bytes char, etc. In this case numtail is not
 251 * added, but Longfilename is stored.
 252 *
 253 * 3) When the one except for the above, or the following special
 254 * character are contained:
 255 *        .   [ ] ; , + =
 256 * numtail is added, and Longfilename must be stored in disk .
 257 */
 258struct shortname_info {
 259        unsigned char lower:1,
 260                      upper:1,
 261                      valid:1;
 262};
 263#define INIT_SHORTNAME_INFO(x)  do {            \
 264        (x)->lower = 1;                         \
 265        (x)->upper = 1;                         \
 266        (x)->valid = 1;                         \
 267} while (0)
 268
 269static inline int to_shortname_char(struct nls_table *nls,
 270                                    unsigned char *buf, int buf_size,
 271                                    wchar_t *src, struct shortname_info *info)
 272{
 273        int len;
 274
 275        if (vfat_skip_char(*src)) {
 276                info->valid = 0;
 277                return 0;
 278        }
 279        if (vfat_replace_char(*src)) {
 280                info->valid = 0;
 281                buf[0] = '_';
 282                return 1;
 283        }
 284
 285        len = nls->uni2char(*src, buf, buf_size);
 286        if (len <= 0) {
 287                info->valid = 0;
 288                buf[0] = '_';
 289                len = 1;
 290        } else if (len == 1) {
 291                unsigned char prev = buf[0];
 292
 293                if (buf[0] >= 0x7F) {
 294                        info->lower = 0;
 295                        info->upper = 0;
 296                }
 297
 298                buf[0] = nls_toupper(nls, buf[0]);
 299                if (isalpha(buf[0])) {
 300                        if (buf[0] == prev)
 301                                info->lower = 0;
 302                        else
 303                                info->upper = 0;
 304                }
 305        } else {
 306                info->lower = 0;
 307                info->upper = 0;
 308        }
 309
 310        return len;
 311}
 312
 313/*
 314 * Given a valid longname, create a unique shortname.  Make sure the
 315 * shortname does not exist
 316 * Returns negative number on error, 0 for a normal
 317 * return, and 1 for valid shortname
 318 */
 319static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
 320                                 wchar_t *uname, int ulen,
 321                                 unsigned char *name_res, unsigned char *lcase)
 322{
 323        struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
 324        wchar_t *ip, *ext_start, *end, *name_start;
 325        unsigned char base[9], ext[4], buf[5], *p;
 326        unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
 327        int chl, chi;
 328        int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
 329        int is_shortname;
 330        struct shortname_info base_info, ext_info;
 331
 332        is_shortname = 1;
 333        INIT_SHORTNAME_INFO(&base_info);
 334        INIT_SHORTNAME_INFO(&ext_info);
 335
 336        /* Now, we need to create a shortname from the long name */
 337        ext_start = end = &uname[ulen];
 338        while (--ext_start >= uname) {
 339                if (*ext_start == 0x002E) {     /* is `.' */
 340                        if (ext_start == end - 1) {
 341                                sz = ulen;
 342                                ext_start = NULL;
 343                        }
 344                        break;
 345                }
 346        }
 347
 348        if (ext_start == uname - 1) {
 349                sz = ulen;
 350                ext_start = NULL;
 351        } else if (ext_start) {
 352                /*
 353                 * Names which start with a dot could be just
 354                 * an extension eg. "...test".  In this case Win95
 355                 * uses the extension as the name and sets no extension.
 356                 */
 357                name_start = &uname[0];
 358                while (name_start < ext_start) {
 359                        if (!vfat_skip_char(*name_start))
 360                                break;
 361                        name_start++;
 362                }
 363                if (name_start != ext_start) {
 364                        sz = ext_start - uname;
 365                        ext_start++;
 366                } else {
 367                        sz = ulen;
 368                        ext_start = NULL;
 369                }
 370        }
 371
 372        numtail_baselen = 6;
 373        numtail2_baselen = 2;
 374        for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
 375                chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
 376                                        ip, &base_info);
 377                if (chl == 0)
 378                        continue;
 379
 380                if (baselen < 2 && (baselen + chl) > 2)
 381                        numtail2_baselen = baselen;
 382                if (baselen < 6 && (baselen + chl) > 6)
 383                        numtail_baselen = baselen;
 384                for (chi = 0; chi < chl; chi++) {
 385                        *p++ = charbuf[chi];
 386                        baselen++;
 387                        if (baselen >= 8)
 388                                break;
 389                }
 390                if (baselen >= 8) {
 391                        if ((chi < chl - 1) || (ip + 1) - uname < sz)
 392                                is_shortname = 0;
 393                        break;
 394                }
 395        }
 396        if (baselen == 0) {
 397                return -EINVAL;
 398        }
 399
 400        extlen = 0;
 401        if (ext_start) {
 402                for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
 403                        chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
 404                                                ip, &ext_info);
 405                        if (chl == 0)
 406                                continue;
 407
 408                        if ((extlen + chl) > 3) {
 409                                is_shortname = 0;
 410                                break;
 411                        }
 412                        for (chi = 0; chi < chl; chi++) {
 413                                *p++ = charbuf[chi];
 414                                extlen++;
 415                        }
 416                        if (extlen >= 3) {
 417                                if (ip + 1 != end)
 418                                        is_shortname = 0;
 419                                break;
 420                        }
 421                }
 422        }
 423        ext[extlen] = '\0';
 424        base[baselen] = '\0';
 425
 426        /* Yes, it can happen. ".\xe5" would do it. */
 427        if (base[0] == DELETED_FLAG)
 428                base[0] = 0x05;
 429
 430        /* OK, at this point we know that base is not longer than 8 symbols,
 431         * ext is not longer than 3, base is nonempty, both don't contain
 432         * any bad symbols (lowercase transformed to uppercase).
 433         */
 434
 435        memset(name_res, ' ', MSDOS_NAME);
 436        memcpy(name_res, base, baselen);
 437        memcpy(name_res + 8, ext, extlen);
 438        *lcase = 0;
 439        if (is_shortname && base_info.valid && ext_info.valid) {
 440                if (vfat_find_form(dir, name_res) == 0)
 441                        return -EEXIST;
 442
 443                if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
 444                        return (base_info.upper && ext_info.upper);
 445                } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
 446                        if ((base_info.upper || base_info.lower) &&
 447                            (ext_info.upper || ext_info.lower)) {
 448                                if (!base_info.upper && base_info.lower)
 449                                        *lcase |= CASE_LOWER_BASE;
 450                                if (!ext_info.upper && ext_info.lower)
 451                                        *lcase |= CASE_LOWER_EXT;
 452                                return 1;
 453                        }
 454                        return 0;
 455                } else {
 456                        BUG();
 457                }
 458        }
 459
 460        if (opts->numtail == 0)
 461                if (vfat_find_form(dir, name_res) < 0)
 462                        return 0;
 463
 464        /*
 465         * Try to find a unique extension.  This used to
 466         * iterate through all possibilities sequentially,
 467         * but that gave extremely bad performance.  Windows
 468         * only tries a few cases before using random
 469         * values for part of the base.
 470         */
 471
 472        if (baselen > 6) {
 473                baselen = numtail_baselen;
 474                name_res[7] = ' ';
 475        }
 476        name_res[baselen] = '~';
 477        for (i = 1; i < 10; i++) {
 478                name_res[baselen + 1] = i + '0';
 479                if (vfat_find_form(dir, name_res) < 0)
 480                        return 0;
 481        }
 482
 483        i = jiffies;
 484        sz = (jiffies >> 16) & 0x7;
 485        if (baselen > 2) {
 486                baselen = numtail2_baselen;
 487                name_res[7] = ' ';
 488        }
 489        name_res[baselen + 4] = '~';
 490        name_res[baselen + 5] = '1' + sz;
 491        while (1) {
 492                snprintf(buf, sizeof(buf), "%04X", i & 0xffff);
 493                memcpy(&name_res[baselen], buf, 4);
 494                if (vfat_find_form(dir, name_res) < 0)
 495                        break;
 496                i -= 11;
 497        }
 498        return 0;
 499}
 500
 501/* Translate a string, including coded sequences into Unicode */
 502static int
 503xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
 504             int *longlen, int *outlen, int escape, int utf8,
 505             struct nls_table *nls)
 506{
 507        const unsigned char *ip;
 508        unsigned char nc;
 509        unsigned char *op;
 510        unsigned int ec;
 511        int i, k, fill;
 512        int charlen;
 513
 514        if (utf8) {
 515                *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN,
 516                                (wchar_t *) outname, FAT_LFN_LEN + 2);
 517                if (*outlen < 0)
 518                        return *outlen;
 519                else if (*outlen > FAT_LFN_LEN)
 520                        return -ENAMETOOLONG;
 521
 522                op = &outname[*outlen * sizeof(wchar_t)];
 523        } else {
 524                for (i = 0, ip = name, op = outname, *outlen = 0;
 525                         i < len && *outlen < FAT_LFN_LEN;
 526                         *outlen += 1) {
 527                        if (escape && (*ip == ':')) {
 528                                if (i > len - 5)
 529                                        return -EINVAL;
 530                                ec = 0;
 531                                for (k = 1; k < 5; k++) {
 532                                        nc = ip[k];
 533                                        ec <<= 4;
 534                                        if (nc >= '0' && nc <= '9') {
 535                                                ec |= nc - '0';
 536                                                continue;
 537                                        }
 538                                        if (nc >= 'a' && nc <= 'f') {
 539                                                ec |= nc - ('a' - 10);
 540                                                continue;
 541                                        }
 542                                        if (nc >= 'A' && nc <= 'F') {
 543                                                ec |= nc - ('A' - 10);
 544                                                continue;
 545                                        }
 546                                        return -EINVAL;
 547                                }
 548                                *op++ = ec & 0xFF;
 549                                *op++ = ec >> 8;
 550                                ip += 5;
 551                                i += 5;
 552                        } else {
 553                                charlen = nls->char2uni(ip, len - i,
 554                                                                        (wchar_t *)op);
 555                                if (charlen < 0)
 556                                        return -EINVAL;
 557                                ip += charlen;
 558                                i += charlen;
 559                                op += 2;
 560                        }
 561                }
 562                if (i < len)
 563                        return -ENAMETOOLONG;
 564        }
 565
 566        *longlen = *outlen;
 567        if (*outlen % 13) {
 568                *op++ = 0;
 569                *op++ = 0;
 570                *outlen += 1;
 571                if (*outlen % 13) {
 572                        fill = 13 - (*outlen % 13);
 573                        for (i = 0; i < fill; i++) {
 574                                *op++ = 0xff;
 575                                *op++ = 0xff;
 576                        }
 577                        *outlen += fill;
 578                }
 579        }
 580
 581        return 0;
 582}
 583
 584static int vfat_build_slots(struct inode *dir, const unsigned char *name,
 585                            int len, int is_dir, int cluster,
 586                            struct timespec *ts,
 587                            struct msdos_dir_slot *slots, int *nr_slots)
 588{
 589        struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 590        struct fat_mount_options *opts = &sbi->options;
 591        struct msdos_dir_slot *ps;
 592        struct msdos_dir_entry *de;
 593        unsigned char cksum, lcase;
 594        unsigned char msdos_name[MSDOS_NAME];
 595        wchar_t *uname;
 596        __le16 time, date;
 597        u8 time_cs;
 598        int err, ulen, usize, i;
 599        loff_t offset;
 600
 601        *nr_slots = 0;
 602
 603        uname = __getname();
 604        if (!uname)
 605                return -ENOMEM;
 606
 607        err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
 608                           opts->unicode_xlate, opts->utf8, sbi->nls_io);
 609        if (err)
 610                goto out_free;
 611
 612        err = vfat_is_used_badchars(uname, ulen);
 613        if (err)
 614                goto out_free;
 615
 616        err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
 617                                    msdos_name, &lcase);
 618        if (err < 0)
 619                goto out_free;
 620        else if (err == 1) {
 621                de = (struct msdos_dir_entry *)slots;
 622                err = 0;
 623                goto shortname;
 624        }
 625
 626        /* build the entry of long file name */
 627        cksum = fat_checksum(msdos_name);
 628
 629        *nr_slots = usize / 13;
 630        for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
 631                ps->id = i;
 632                ps->attr = ATTR_EXT;
 633                ps->reserved = 0;
 634                ps->alias_checksum = cksum;
 635                ps->start = 0;
 636                offset = (i - 1) * 13;
 637                fatwchar_to16(ps->name0_4, uname + offset, 5);
 638                fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
 639                fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
 640        }
 641        slots[0].id |= 0x40;
 642        de = (struct msdos_dir_entry *)ps;
 643
 644shortname:
 645        /* build the entry of 8.3 alias name */
 646        (*nr_slots)++;
 647        memcpy(de->name, msdos_name, MSDOS_NAME);
 648        de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 649        de->lcase = lcase;
 650        fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
 651        de->time = de->ctime = time;
 652        de->date = de->cdate = de->adate = date;
 653        de->ctime_cs = time_cs;
 654        fat_set_start(de, cluster);
 655        de->size = 0;
 656out_free:
 657        __putname(uname);
 658        return err;
 659}
 660
 661static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir,
 662                          int cluster, struct timespec *ts,
 663                          struct fat_slot_info *sinfo)
 664{
 665        struct msdos_dir_slot *slots;
 666        unsigned int len;
 667        int err, nr_slots;
 668
 669        len = vfat_striptail_len(qname);
 670        if (len == 0)
 671                return -ENOENT;
 672
 673        slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS);
 674        if (slots == NULL)
 675                return -ENOMEM;
 676
 677        err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
 678                               slots, &nr_slots);
 679        if (err)
 680                goto cleanup;
 681
 682        err = fat_add_entries(dir, slots, nr_slots, sinfo);
 683        if (err)
 684                goto cleanup;
 685
 686        /* update timestamp */
 687        dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
 688        if (IS_DIRSYNC(dir))
 689                (void)fat_sync_inode(dir);
 690        else
 691                mark_inode_dirty(dir);
 692cleanup:
 693        kfree(slots);
 694        return err;
 695}
 696
 697static int vfat_find(struct inode *dir, struct qstr *qname,
 698                     struct fat_slot_info *sinfo)
 699{
 700        unsigned int len = vfat_striptail_len(qname);
 701        if (len == 0)
 702                return -ENOENT;
 703        return fat_search_long(dir, qname->name, len, sinfo);
 704}
 705
 706/*
 707 * (nfsd's) anonymous disconnected dentry?
 708 * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job).
 709 */
 710static int vfat_d_anon_disconn(struct dentry *dentry)
 711{
 712        return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED);
 713}
 714
 715static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
 716                                  unsigned int flags)
 717{
 718        struct super_block *sb = dir->i_sb;
 719        struct fat_slot_info sinfo;
 720        struct inode *inode;
 721        struct dentry *alias;
 722        int err;
 723
 724        lock_super(sb);
 725
 726        err = vfat_find(dir, &dentry->d_name, &sinfo);
 727        if (err) {
 728                if (err == -ENOENT) {
 729                        inode = NULL;
 730                        goto out;
 731                }
 732                goto error;
 733        }
 734
 735        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 736        brelse(sinfo.bh);
 737        if (IS_ERR(inode)) {
 738                err = PTR_ERR(inode);
 739                goto error;
 740        }
 741
 742        alias = d_find_alias(inode);
 743        if (alias && !vfat_d_anon_disconn(alias)) {
 744                /*
 745                 * This inode has non anonymous-DCACHE_DISCONNECTED
 746                 * dentry. This means, the user did ->lookup() by an
 747                 * another name (longname vs 8.3 alias of it) in past.
 748                 *
 749                 * Switch to new one for reason of locality if possible.
 750                 */
 751                BUG_ON(d_unhashed(alias));
 752                if (!S_ISDIR(inode->i_mode))
 753                        d_move(alias, dentry);
 754                iput(inode);
 755                unlock_super(sb);
 756                return alias;
 757        } else
 758                dput(alias);
 759
 760out:
 761        unlock_super(sb);
 762        dentry->d_time = dentry->d_parent->d_inode->i_version;
 763        dentry = d_splice_alias(inode, dentry);
 764        if (dentry)
 765                dentry->d_time = dentry->d_parent->d_inode->i_version;
 766        return dentry;
 767
 768error:
 769        unlock_super(sb);
 770        return ERR_PTR(err);
 771}
 772
 773static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 774                       bool excl)
 775{
 776        struct super_block *sb = dir->i_sb;
 777        struct inode *inode;
 778        struct fat_slot_info sinfo;
 779        struct timespec ts;
 780        int err;
 781
 782        lock_super(sb);
 783
 784        ts = CURRENT_TIME_SEC;
 785        err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
 786        if (err)
 787                goto out;
 788        dir->i_version++;
 789
 790        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 791        brelse(sinfo.bh);
 792        if (IS_ERR(inode)) {
 793                err = PTR_ERR(inode);
 794                goto out;
 795        }
 796        inode->i_version++;
 797        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 798        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 799
 800        dentry->d_time = dentry->d_parent->d_inode->i_version;
 801        d_instantiate(dentry, inode);
 802out:
 803        unlock_super(sb);
 804        return err;
 805}
 806
 807static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
 808{
 809        struct inode *inode = dentry->d_inode;
 810        struct super_block *sb = dir->i_sb;
 811        struct fat_slot_info sinfo;
 812        int err;
 813
 814        lock_super(sb);
 815
 816        err = fat_dir_empty(inode);
 817        if (err)
 818                goto out;
 819        err = vfat_find(dir, &dentry->d_name, &sinfo);
 820        if (err)
 821                goto out;
 822
 823        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 824        if (err)
 825                goto out;
 826        drop_nlink(dir);
 827
 828        clear_nlink(inode);
 829        inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
 830        fat_detach(inode);
 831out:
 832        unlock_super(sb);
 833
 834        return err;
 835}
 836
 837static int vfat_unlink(struct inode *dir, struct dentry *dentry)
 838{
 839        struct inode *inode = dentry->d_inode;
 840        struct super_block *sb = dir->i_sb;
 841        struct fat_slot_info sinfo;
 842        int err;
 843
 844        lock_super(sb);
 845
 846        err = vfat_find(dir, &dentry->d_name, &sinfo);
 847        if (err)
 848                goto out;
 849
 850        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 851        if (err)
 852                goto out;
 853        clear_nlink(inode);
 854        inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
 855        fat_detach(inode);
 856out:
 857        unlock_super(sb);
 858
 859        return err;
 860}
 861
 862static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 863{
 864        struct super_block *sb = dir->i_sb;
 865        struct inode *inode;
 866        struct fat_slot_info sinfo;
 867        struct timespec ts;
 868        int err, cluster;
 869
 870        lock_super(sb);
 871
 872        ts = CURRENT_TIME_SEC;
 873        cluster = fat_alloc_new_dir(dir, &ts);
 874        if (cluster < 0) {
 875                err = cluster;
 876                goto out;
 877        }
 878        err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
 879        if (err)
 880                goto out_free;
 881        dir->i_version++;
 882        inc_nlink(dir);
 883
 884        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 885        brelse(sinfo.bh);
 886        if (IS_ERR(inode)) {
 887                err = PTR_ERR(inode);
 888                /* the directory was completed, just return a error */
 889                goto out;
 890        }
 891        inode->i_version++;
 892        set_nlink(inode, 2);
 893        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 894        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 895
 896        dentry->d_time = dentry->d_parent->d_inode->i_version;
 897        d_instantiate(dentry, inode);
 898
 899        unlock_super(sb);
 900        return 0;
 901
 902out_free:
 903        fat_free_clusters(dir, cluster);
 904out:
 905        unlock_super(sb);
 906        return err;
 907}
 908
 909static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 910                       struct inode *new_dir, struct dentry *new_dentry)
 911{
 912        struct buffer_head *dotdot_bh;
 913        struct msdos_dir_entry *dotdot_de;
 914        struct inode *old_inode, *new_inode;
 915        struct fat_slot_info old_sinfo, sinfo;
 916        struct timespec ts;
 917        loff_t dotdot_i_pos, new_i_pos;
 918        int err, is_dir, update_dotdot, corrupt = 0;
 919        struct super_block *sb = old_dir->i_sb;
 920
 921        old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 922        old_inode = old_dentry->d_inode;
 923        new_inode = new_dentry->d_inode;
 924        lock_super(sb);
 925        err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
 926        if (err)
 927                goto out;
 928
 929        is_dir = S_ISDIR(old_inode->i_mode);
 930        update_dotdot = (is_dir && old_dir != new_dir);
 931        if (update_dotdot) {
 932                if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
 933                                         &dotdot_i_pos) < 0) {
 934                        err = -EIO;
 935                        goto out;
 936                }
 937        }
 938
 939        ts = CURRENT_TIME_SEC;
 940        if (new_inode) {
 941                if (is_dir) {
 942                        err = fat_dir_empty(new_inode);
 943                        if (err)
 944                                goto out;
 945                }
 946                new_i_pos = MSDOS_I(new_inode)->i_pos;
 947                fat_detach(new_inode);
 948        } else {
 949                err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
 950                                     &ts, &sinfo);
 951                if (err)
 952                        goto out;
 953                new_i_pos = sinfo.i_pos;
 954        }
 955        new_dir->i_version++;
 956
 957        fat_detach(old_inode);
 958        fat_attach(old_inode, new_i_pos);
 959        if (IS_DIRSYNC(new_dir)) {
 960                err = fat_sync_inode(old_inode);
 961                if (err)
 962                        goto error_inode;
 963        } else
 964                mark_inode_dirty(old_inode);
 965
 966        if (update_dotdot) {
 967                fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
 968                mark_buffer_dirty_inode(dotdot_bh, old_inode);
 969                if (IS_DIRSYNC(new_dir)) {
 970                        err = sync_dirty_buffer(dotdot_bh);
 971                        if (err)
 972                                goto error_dotdot;
 973                }
 974                drop_nlink(old_dir);
 975                if (!new_inode)
 976                        inc_nlink(new_dir);
 977        }
 978
 979        err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
 980        old_sinfo.bh = NULL;
 981        if (err)
 982                goto error_dotdot;
 983        old_dir->i_version++;
 984        old_dir->i_ctime = old_dir->i_mtime = ts;
 985        if (IS_DIRSYNC(old_dir))
 986                (void)fat_sync_inode(old_dir);
 987        else
 988                mark_inode_dirty(old_dir);
 989
 990        if (new_inode) {
 991                drop_nlink(new_inode);
 992                if (is_dir)
 993                        drop_nlink(new_inode);
 994                new_inode->i_ctime = ts;
 995        }
 996out:
 997        brelse(sinfo.bh);
 998        brelse(dotdot_bh);
 999        brelse(old_sinfo.bh);
1000        unlock_super(sb);
1001
1002        return err;
1003
1004error_dotdot:
1005        /* data cluster is shared, serious corruption */
1006        corrupt = 1;
1007
1008        if (update_dotdot) {
1009                fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
1010                mark_buffer_dirty_inode(dotdot_bh, old_inode);
1011                corrupt |= sync_dirty_buffer(dotdot_bh);
1012        }
1013error_inode:
1014        fat_detach(old_inode);
1015        fat_attach(old_inode, old_sinfo.i_pos);
1016        if (new_inode) {
1017                fat_attach(new_inode, new_i_pos);
1018                if (corrupt)
1019                        corrupt |= fat_sync_inode(new_inode);
1020        } else {
1021                /*
1022                 * If new entry was not sharing the data cluster, it
1023                 * shouldn't be serious corruption.
1024                 */
1025                int err2 = fat_remove_entries(new_dir, &sinfo);
1026                if (corrupt)
1027                        corrupt |= err2;
1028                sinfo.bh = NULL;
1029        }
1030        if (corrupt < 0) {
1031                fat_fs_error(new_dir->i_sb,
1032                             "%s: Filesystem corrupted (i_pos %lld)",
1033                             __func__, sinfo.i_pos);
1034        }
1035        goto out;
1036}
1037
1038static const struct inode_operations vfat_dir_inode_operations = {
1039        .create         = vfat_create,
1040        .lookup         = vfat_lookup,
1041        .unlink         = vfat_unlink,
1042        .mkdir          = vfat_mkdir,
1043        .rmdir          = vfat_rmdir,
1044        .rename         = vfat_rename,
1045        .setattr        = fat_setattr,
1046        .getattr        = fat_getattr,
1047};
1048
1049static void setup(struct super_block *sb)
1050{
1051        MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations;
1052        if (MSDOS_SB(sb)->options.name_check != 's')
1053                sb->s_d_op = &vfat_ci_dentry_ops;
1054        else
1055                sb->s_d_op = &vfat_dentry_ops;
1056}
1057
1058static int vfat_fill_super(struct super_block *sb, void *data, int silent)
1059{
1060        return fat_fill_super(sb, data, silent, 1, setup);
1061}
1062
1063static struct dentry *vfat_mount(struct file_system_type *fs_type,
1064                       int flags, const char *dev_name,
1065                       void *data)
1066{
1067        return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super);
1068}
1069
1070static struct file_system_type vfat_fs_type = {
1071        .owner          = THIS_MODULE,
1072        .name           = "vfat",
1073        .mount          = vfat_mount,
1074        .kill_sb        = kill_block_super,
1075        .fs_flags       = FS_REQUIRES_DEV,
1076};
1077
1078static int __init init_vfat_fs(void)
1079{
1080        return register_filesystem(&vfat_fs_type);
1081}
1082
1083static void __exit exit_vfat_fs(void)
1084{
1085        unregister_filesystem(&vfat_fs_type);
1086}
1087
1088MODULE_LICENSE("GPL");
1089MODULE_DESCRIPTION("VFAT filesystem support");
1090MODULE_AUTHOR("Gordon Chaffee");
1091
1092module_init(init_vfat_fs)
1093module_exit(exit_vfat_fs)
1094
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.