1 files changed, 1098 insertions, 0 deletions

diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
new file mode 100644
index 000000000000..bf326d4356a3
--- /dev/null
+++ b/fs/fat/namei_vfat.c
@@ -0,0 +1,1098 @@
+/*
+ *  linux/fs/vfat/namei.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *
+ *  Windows95/Windows NT compatible extended MSDOS filesystem
+ *    by Gordon Chaffee Copyright (C) 1995.  Send bug reports for the
+ *    VFAT filesystem to <chaffee@cs.berkeley.edu>.  Specify
+ *    what file operation caused you trouble and if you can duplicate
+ *    the problem, send a script that demonstrates it.
+ *
+ *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
+ *
+ *  Support Multibyte characters and cleanup by
+ *                              OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/buffer_head.h>
+#include <linux/namei.h>
+#include "fat.h"
+
+/*
+ * If new entry was created in the parent, it could create the 8.3
+ * alias (the shortname of logname).  So, the parent may have the
+ * negative-dentry which matches the created 8.3 alias.
+ *
+ * If it happened, the negative dentry isn't actually negative
+ * anymore.  So, drop it.
+ */
+static int vfat_revalidate_shortname(struct dentry *dentry)
+{
+        int ret = 1;
+        spin_lock(&dentry->d_lock);
+        if (dentry->d_time != dentry->d_parent->d_inode->i_version)
+                ret = 0;
+        spin_unlock(&dentry->d_lock);
+        return ret;
+}
+
+static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+        /* This is not negative dentry. Always valid. */
+        if (dentry->d_inode)
+                return 1;
+        return vfat_revalidate_shortname(dentry);
+}
+
+static int vfat_revalidate_ci(struct dentry *dentry, struct nameidata *nd)
+{
+        /*
+         * This is not negative dentry. Always valid.
+         *
+         * Note, rename() to existing directory entry will have ->d_inode,
+         * and will use existing name which isn't specified name by user.
+         *
+         * We may be able to drop this positive dentry here. But dropping
+         * positive dentry isn't good idea. So it's unsupported like
+         * rename("filename", "FILENAME") for now.
+         */
+        if (dentry->d_inode)
+                return 1;
+
+        /*
+         * This may be nfsd (or something), anyway, we can't see the
+         * intent of this. So, since this can be for creation, drop it.
+         */
+        if (!nd)
+                return 0;
+
+        /*
+         * Drop the negative dentry, in order to make sure to use the
+         * case sensitive name which is specified by user if this is
+         * for creation.
+         */
+        if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
+                if (nd->flags & LOOKUP_CREATE)
+                        return 0;
+        }
+
+        return vfat_revalidate_shortname(dentry);
+}
+
+/* returns the length of a struct qstr, ignoring trailing dots */
+static unsigned int vfat_striptail_len(struct qstr *qstr)
+{
+        unsigned int len = qstr->len;
+
+        while (len && qstr->name[len - 1] == '.')
+                len--;
+        return len;
+}
+
+/*
+ * Compute the hash for the vfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The vfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int vfat_hash(struct dentry *dentry, struct qstr *qstr)
+{
+        qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
+        return 0;
+}
+
+/*
+ * Compute the hash for the vfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The vfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int vfat_hashi(struct dentry *dentry, struct qstr *qstr)
+{
+        struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
+        const unsigned char *name;
+        unsigned int len;
+        unsigned long hash;
+
+        name = qstr->name;
+        len = vfat_striptail_len(qstr);
+
+        hash = init_name_hash();
+        while (len--)
+                hash = partial_name_hash(nls_tolower(t, *name++), hash);
+        qstr->hash = end_name_hash(hash);
+
+        return 0;
+}
+
+/*
+ * Case insensitive compare of two vfat names.
+ */
+static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b)
+{
+        struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
+        unsigned int alen, blen;
+
+        /* A filename cannot end in '.' or we treat it like it has none */
+        alen = vfat_striptail_len(a);
+        blen = vfat_striptail_len(b);
+        if (alen == blen) {
+                if (nls_strnicmp(t, a->name, b->name, alen) == 0)
+                        return 0;
+        }
+        return 1;
+}
+
+/*
+ * Case sensitive compare of two vfat names.
+ */
+static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
+{
+        unsigned int alen, blen;
+
+        /* A filename cannot end in '.' or we treat it like it has none */
+        alen = vfat_striptail_len(a);
+        blen = vfat_striptail_len(b);
+        if (alen == blen) {
+                if (strncmp(a->name, b->name, alen) == 0)
+                        return 0;
+        }
+        return 1;
+}
+
+static struct dentry_operations vfat_ci_dentry_ops = {
+        .d_revalidate   = vfat_revalidate_ci,
+        .d_hash         = vfat_hashi,
+        .d_compare      = vfat_cmpi,
+};
+
+static struct dentry_operations vfat_dentry_ops = {
+        .d_revalidate   = vfat_revalidate,
+        .d_hash         = vfat_hash,
+        .d_compare      = vfat_cmp,
+};
+
+/* Characters that are undesirable in an MS-DOS file name */
+
+static inline wchar_t vfat_bad_char(wchar_t w)
+{
+        return (w < 0x0020)
+            || (w == '*') || (w == '?') || (w == '<') || (w == '>')
+            || (w == '|') || (w == '"') || (w == ':') || (w == '/')
+            || (w == '\\');
+}
+
+static inline wchar_t vfat_replace_char(wchar_t w)
+{
+        return (w == '[') || (w == ']') || (w == ';') || (w == ',')
+            || (w == '+') || (w == '=');
+}
+
+static wchar_t vfat_skip_char(wchar_t w)
+{
+        return (w == '.') || (w == ' ');
+}
+
+static inline int vfat_is_used_badchars(const wchar_t *s, int len)
+{
+        int i;
+
+        for (i = 0; i < len; i++)
+                if (vfat_bad_char(s[i]))
+                        return -EINVAL;
+
+        if (s[i - 1] == ' ') /* last character cannot be space */
+                return -EINVAL;
+
+        return 0;
+}
+
+static int vfat_find_form(struct inode *dir, unsigned char *name)
+{
+        struct fat_slot_info sinfo;
+        int err = fat_scan(dir, name, &sinfo);
+        if (err)
+                return -ENOENT;
+        brelse(sinfo.bh);
+        return 0;
+}
+
+/*
+ * 1) Valid characters for the 8.3 format alias are any combination of
+ * letters, uppercase alphabets, digits, any of the
+ * following special characters:
+ *     $ % ' ` - @ { } ~ ! # ( ) & _ ^
+ * In this case Longfilename is not stored in disk.
+ *
+ * WinNT's Extension:
+ * File name and extension name is contain uppercase/lowercase
+ * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
+ *
+ * 2) File name is 8.3 format, but it contain the uppercase and
+ * lowercase char, muliti bytes char, etc. In this case numtail is not
+ * added, but Longfilename is stored.
+ *
+ * 3) When the one except for the above, or the following special
+ * character are contained:
+ *        .   [ ] ; , + =
+ * numtail is added, and Longfilename must be stored in disk .
+ */
+struct shortname_info {
+        unsigned char lower:1,
+                      upper:1,
+                      valid:1;
+};
+#define INIT_SHORTNAME_INFO(x)  do {            \
+        (x)->lower = 1;                         \
+        (x)->upper = 1;                         \
+        (x)->valid = 1;                         \
+} while (0)
+
+static inline int to_shortname_char(struct nls_table *nls,
+                                    unsigned char *buf, int buf_size,
+                                    wchar_t *src, struct shortname_info *info)
+{
+        int len;
+
+        if (vfat_skip_char(*src)) {
+                info->valid = 0;
+                return 0;
+        }
+        if (vfat_replace_char(*src)) {
+                info->valid = 0;
+                buf[0] = '_';
+                return 1;
+        }
+
+        len = nls->uni2char(*src, buf, buf_size);
+        if (len <= 0) {
+                info->valid = 0;
+                buf[0] = '_';
+                len = 1;
+        } else if (len == 1) {
+                unsigned char prev = buf[0];
+
+                if (buf[0] >= 0x7F) {
+                        info->lower = 0;
+                        info->upper = 0;
+                }
+
+                buf[0] = nls_toupper(nls, buf[0]);
+                if (isalpha(buf[0])) {
+                        if (buf[0] == prev)
+                                info->lower = 0;
+                        else
+                                info->upper = 0;
+                }
+        } else {
+                info->lower = 0;
+                info->upper = 0;
+        }
+
+        return len;
+}
+
+/*
+ * Given a valid longname, create a unique shortname.  Make sure the
+ * shortname does not exist
+ * Returns negative number on error, 0 for a normal
+ * return, and 1 for valid shortname
+ */
+static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
+                                 wchar_t *uname, int ulen,
+                                 unsigned char *name_res, unsigned char *lcase)
+{
+        struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
+        wchar_t *ip, *ext_start, *end, *name_start;
+        unsigned char base[9], ext[4], buf[8], *p;
+        unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
+        int chl, chi;
+        int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
+        int is_shortname;
+        struct shortname_info base_info, ext_info;
+
+        is_shortname = 1;
+        INIT_SHORTNAME_INFO(&base_info);
+        INIT_SHORTNAME_INFO(&ext_info);
+
+        /* Now, we need to create a shortname from the long name */
+        ext_start = end = &uname[ulen];
+        while (--ext_start >= uname) {
+                if (*ext_start == 0x002E) {     /* is `.' */
+                        if (ext_start == end - 1) {
+                                sz = ulen;
+                                ext_start = NULL;
+                        }
+                        break;
+                }
+        }
+
+        if (ext_start == uname - 1) {
+                sz = ulen;
+                ext_start = NULL;
+        } else if (ext_start) {
+                /*
+                 * Names which start with a dot could be just
+                 * an extension eg. "...test".  In this case Win95
+                 * uses the extension as the name and sets no extension.
+                 */
+                name_start = &uname[0];
+                while (name_start < ext_start) {
+                        if (!vfat_skip_char(*name_start))
+                                break;
+                        name_start++;
+                }
+                if (name_start != ext_start) {
+                        sz = ext_start - uname;
+                        ext_start++;
+                } else {
+                        sz = ulen;
+                        ext_start = NULL;
+                }
+        }
+
+        numtail_baselen = 6;
+        numtail2_baselen = 2;
+        for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
+                chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
+                                        ip, &base_info);
+                if (chl == 0)
+                        continue;
+
+                if (baselen < 2 && (baselen + chl) > 2)
+                        numtail2_baselen = baselen;
+                if (baselen < 6 && (baselen + chl) > 6)
+                        numtail_baselen = baselen;
+                for (chi = 0; chi < chl; chi++) {
+                        *p++ = charbuf[chi];
+                        baselen++;
+                        if (baselen >= 8)
+                                break;
+                }
+                if (baselen >= 8) {
+                        if ((chi < chl - 1) || (ip + 1) - uname < sz)
+                                is_shortname = 0;
+                        break;
+                }
+        }
+        if (baselen == 0) {
+                return -EINVAL;
+        }
+
+        extlen = 0;
+        if (ext_start) {
+                for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
+                        chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
+                                                ip, &ext_info);
+                        if (chl == 0)
+                                continue;
+
+                        if ((extlen + chl) > 3) {
+                                is_shortname = 0;
+                                break;
+                        }
+                        for (chi = 0; chi < chl; chi++) {
+                                *p++ = charbuf[chi];
+                                extlen++;
+                        }
+                        if (extlen >= 3) {
+                                if (ip + 1 != end)
+                                        is_shortname = 0;
+                                break;
+                        }
+                }
+        }
+        ext[extlen] = '\0';
+        base[baselen] = '\0';
+
+        /* Yes, it can happen. ".\xe5" would do it. */
+        if (base[0] == DELETED_FLAG)
+                base[0] = 0x05;
+
+        /* OK, at this point we know that base is not longer than 8 symbols,
+         * ext is not longer than 3, base is nonempty, both don't contain
+         * any bad symbols (lowercase transformed to uppercase).
+         */
+
+        memset(name_res, ' ', MSDOS_NAME);
+        memcpy(name_res, base, baselen);
+        memcpy(name_res + 8, ext, extlen);
+        *lcase = 0;
+        if (is_shortname && base_info.valid && ext_info.valid) {
+                if (vfat_find_form(dir, name_res) == 0)
+                        return -EEXIST;
+
+                if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
+                        return (base_info.upper && ext_info.upper);
+                } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
+                        if ((base_info.upper || base_info.lower) &&
+                            (ext_info.upper || ext_info.lower)) {
+                                if (!base_info.upper && base_info.lower)
+                                        *lcase |= CASE_LOWER_BASE;
+                                if (!ext_info.upper && ext_info.lower)
+                                        *lcase |= CASE_LOWER_EXT;
+                                return 1;
+                        }
+                        return 0;
+                } else {
+                        BUG();
+                }
+        }
+
+        if (opts->numtail == 0)
+                if (vfat_find_form(dir, name_res) < 0)
+                        return 0;
+
+        /*
+         * Try to find a unique extension.  This used to
+         * iterate through all possibilities sequentially,
+         * but that gave extremely bad performance.  Windows
+         * only tries a few cases before using random
+         * values for part of the base.
+         */
+
+        if (baselen > 6) {
+                baselen = numtail_baselen;
+                name_res[7] = ' ';
+        }
+        name_res[baselen] = '~';
+        for (i = 1; i < 10; i++) {
+                name_res[baselen + 1] = i + '0';
+                if (vfat_find_form(dir, name_res) < 0)
+                        return 0;
+        }
+
+        i = jiffies & 0xffff;
+        sz = (jiffies >> 16) & 0x7;
+        if (baselen > 2) {
+                baselen = numtail2_baselen;
+                name_res[7] = ' ';
+        }
+        name_res[baselen + 4] = '~';
+        name_res[baselen + 5] = '1' + sz;
+        while (1) {
+                sprintf(buf, "%04X", i);
+                memcpy(&name_res[baselen], buf, 4);
+                if (vfat_find_form(dir, name_res) < 0)
+                        break;
+                i -= 11;
+        }
+        return 0;
+}
+
+/* Translate a string, including coded sequences into Unicode */
+static int
+xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
+             int *longlen, int *outlen, int escape, int utf8,
+             struct nls_table *nls)
+{
+        const unsigned char *ip;
+        unsigned char nc;
+        unsigned char *op;
+        unsigned int ec;
+        int i, k, fill;
+        int charlen;
+
+        if (utf8) {
+                int name_len = strlen(name);
+
+                *outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX);
+
+                /*
+                 * We stripped '.'s before and set len appropriately,
+                 * but utf8_mbstowcs doesn't care about len
+                 */
+                *outlen -= (name_len - len);
+
+                if (*outlen > 255)
+                        return -ENAMETOOLONG;
+
+                op = &outname[*outlen * sizeof(wchar_t)];
+        } else {
+                if (nls) {
+                        for (i = 0, ip = name, op = outname, *outlen = 0;
+                             i < len && *outlen <= 255;
+                             *outlen += 1)
+                        {
+                                if (escape && (*ip == ':')) {
+                                        if (i > len - 5)
+                                                return -EINVAL;
+                                        ec = 0;
+                                        for (k = 1; k < 5; k++) {
+                                                nc = ip[k];
+                                                ec <<= 4;
+                                                if (nc >= '0' && nc <= '9') {
+                                                        ec |= nc - '0';
+                                                        continue;
+                                                }
+                                                if (nc >= 'a' && nc <= 'f') {
+                                                        ec |= nc - ('a' - 10);
+                                                        continue;
+                                                }
+                                                if (nc >= 'A' && nc <= 'F') {
+                                                        ec |= nc - ('A' - 10);
+                                                        continue;
+                                                }
+                                                return -EINVAL;
+                                        }
+                                        *op++ = ec & 0xFF;
+                                        *op++ = ec >> 8;
+                                        ip += 5;
+                                        i += 5;
+                                } else {
+                                        if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0)
+                                                return -EINVAL;
+                                        ip += charlen;
+                                        i += charlen;
+                                        op += 2;
+                                }
+                        }
+                        if (i < len)
+                                return -ENAMETOOLONG;
+                } else {
+                        for (i = 0, ip = name, op = outname, *outlen = 0;
+                             i < len && *outlen <= 255;
+                             i++, *outlen += 1)
+                        {
+                                *op++ = *ip++;
+                                *op++ = 0;
+                        }
+                        if (i < len)
+                                return -ENAMETOOLONG;
+                }
+        }
+
+        *longlen = *outlen;
+        if (*outlen % 13) {
+                *op++ = 0;
+                *op++ = 0;
+                *outlen += 1;
+                if (*outlen % 13) {
+                        fill = 13 - (*outlen % 13);
+                        for (i = 0; i < fill; i++) {
+                                *op++ = 0xff;
+                                *op++ = 0xff;
+                        }
+                        *outlen += fill;
+                }
+        }
+
+        return 0;
+}
+
+static int vfat_build_slots(struct inode *dir, const unsigned char *name,
+                            int len, int is_dir, int cluster,
+                            struct timespec *ts,
+                            struct msdos_dir_slot *slots, int *nr_slots)
+{
+        struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+        struct fat_mount_options *opts = &sbi->options;
+        struct msdos_dir_slot *ps;
+        struct msdos_dir_entry *de;
+        unsigned char cksum, lcase;
+        unsigned char msdos_name[MSDOS_NAME];
+        wchar_t *uname;
+        __le16 time, date;
+        u8 time_cs;
+        int err, ulen, usize, i;
+        loff_t offset;
+
+        *nr_slots = 0;
+
+        uname = __getname();
+        if (!uname)
+                return -ENOMEM;
+
+        err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
+                           opts->unicode_xlate, opts->utf8, sbi->nls_io);
+        if (err)
+                goto out_free;
+
+        err = vfat_is_used_badchars(uname, ulen);
+        if (err)
+                goto out_free;
+
+        err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
+                                    msdos_name, &lcase);
+        if (err < 0)
+                goto out_free;
+        else if (err == 1) {
+                de = (struct msdos_dir_entry *)slots;
+                err = 0;
+                goto shortname;
+        }
+
+        /* build the entry of long file name */
+        cksum = fat_checksum(msdos_name);
+
+        *nr_slots = usize / 13;
+        for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
+                ps->id = i;
+                ps->attr = ATTR_EXT;
+                ps->reserved = 0;
+                ps->alias_checksum = cksum;
+                ps->start = 0;
+                offset = (i - 1) * 13;
+                fatwchar_to16(ps->name0_4, uname + offset, 5);
+                fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
+                fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
+        }
+        slots[0].id |= 0x40;
+        de = (struct msdos_dir_entry *)ps;
+
+shortname:
+        /* build the entry of 8.3 alias name */
+        (*nr_slots)++;
+        memcpy(de->name, msdos_name, MSDOS_NAME);
+        de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
+        de->lcase = lcase;
+        fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
+        de->time = de->ctime = time;
+        de->date = de->cdate = de->adate = date;
+        de->ctime_cs = time_cs;
+        de->start = cpu_to_le16(cluster);
+        de->starthi = cpu_to_le16(cluster >> 16);
+        de->size = 0;
+out_free:
+        __putname(uname);
+        return err;
+}
+
+static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir,
+                          int cluster, struct timespec *ts,
+                          struct fat_slot_info *sinfo)
+{
+        struct msdos_dir_slot *slots;
+        unsigned int len;
+        int err, nr_slots;
+
+        len = vfat_striptail_len(qname);
+        if (len == 0)
+                return -ENOENT;
+
+        slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS);
+        if (slots == NULL)
+                return -ENOMEM;
+
+        err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
+                               slots, &nr_slots);
+        if (err)
+                goto cleanup;
+
+        err = fat_add_entries(dir, slots, nr_slots, sinfo);
+        if (err)
+                goto cleanup;
+
+        /* update timestamp */
+        dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
+        if (IS_DIRSYNC(dir))
+                (void)fat_sync_inode(dir);
+        else
+                mark_inode_dirty(dir);
+cleanup:
+        kfree(slots);
+        return err;
+}
+
+static int vfat_find(struct inode *dir, struct qstr *qname,
+                     struct fat_slot_info *sinfo)
+{
+        unsigned int len = vfat_striptail_len(qname);
+        if (len == 0)
+                return -ENOENT;
+        return fat_search_long(dir, qname->name, len, sinfo);
+}
+
+static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
+                                  struct nameidata *nd)
+{
+        struct super_block *sb = dir->i_sb;
+        struct fat_slot_info sinfo;
+        struct inode *inode;
+        struct dentry *alias;
+        int err;
+
+        lock_super(sb);
+
+        err = vfat_find(dir, &dentry->d_name, &sinfo);
+        if (err) {
+                if (err == -ENOENT) {
+                        inode = NULL;
+                        goto out;
+                }
+                goto error;
+        }
+
+        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+        brelse(sinfo.bh);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                goto error;
+        }
+
+        alias = d_find_alias(inode);
+        if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
+                /*
+                 * This inode has non DCACHE_DISCONNECTED dentry. This
+                 * means, the user did ->lookup() by an another name
+                 * (longname vs 8.3 alias of it) in past.
+                 *
+                 * Switch to new one for reason of locality if possible.
+                 */
+                BUG_ON(d_unhashed(alias));
+                if (!S_ISDIR(inode->i_mode))
+                        d_move(alias, dentry);
+                iput(inode);
+                unlock_super(sb);
+                return alias;
+        }
+out:
+        unlock_super(sb);
+        dentry->d_op = sb->s_root->d_op;
+        dentry->d_time = dentry->d_parent->d_inode->i_version;
+        dentry = d_splice_alias(inode, dentry);
+        if (dentry) {
+                dentry->d_op = sb->s_root->d_op;
+                dentry->d_time = dentry->d_parent->d_inode->i_version;
+        }
+        return dentry;
+
+error:
+        unlock_super(sb);
+        return ERR_PTR(err);
+}
+
+static int vfat_create(struct inode *dir, struct dentry *dentry, int mode,
+                       struct nameidata *nd)
+{
+        struct super_block *sb = dir->i_sb;
+        struct inode *inode;
+        struct fat_slot_info sinfo;
+        struct timespec ts;
+        int err;
+
+        lock_super(sb);
+
+        ts = CURRENT_TIME_SEC;
+        err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
+        if (err)
+                goto out;
+        dir->i_version++;
+
+        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+        brelse(sinfo.bh);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                goto out;
+        }
+        inode->i_version++;
+        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+        dentry->d_time = dentry->d_parent->d_inode->i_version;
+        d_instantiate(dentry, inode);
+out:
+        unlock_super(sb);
+        return err;
+}
+
+static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
+{
+        struct inode *inode = dentry->d_inode;
+        struct super_block *sb = dir->i_sb;
+        struct fat_slot_info sinfo;
+        int err;
+
+        lock_super(sb);
+
+        err = fat_dir_empty(inode);
+        if (err)
+                goto out;
+        err = vfat_find(dir, &dentry->d_name, &sinfo);
+        if (err)
+                goto out;
+
+        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
+        if (err)
+                goto out;
+        drop_nlink(dir);
+
+        clear_nlink(inode);
+        inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
+        fat_detach(inode);
+out:
+        unlock_super(sb);
+
+        return err;
+}
+
+static int vfat_unlink(struct inode *dir, struct dentry *dentry)
+{
+        struct inode *inode = dentry->d_inode;
+        struct super_block *sb = dir->i_sb;
+        struct fat_slot_info sinfo;
+        int err;
+
+        lock_super(sb);
+
+        err = vfat_find(dir, &dentry->d_name, &sinfo);
+        if (err)
+                goto out;
+
+        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
+        if (err)
+                goto out;
+        clear_nlink(inode);
+        inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
+        fat_detach(inode);
+out:
+        unlock_super(sb);
+
+        return err;
+}
+
+static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+        struct super_block *sb = dir->i_sb;
+        struct inode *inode;
+        struct fat_slot_info sinfo;
+        struct timespec ts;
+        int err, cluster;
+
+        lock_super(sb);
+
+        ts = CURRENT_TIME_SEC;
+        cluster = fat_alloc_new_dir(dir, &ts);
+        if (cluster < 0) {
+                err = cluster;
+                goto out;
+        }
+        err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
+        if (err)
+                goto out_free;
+        dir->i_version++;
+        inc_nlink(dir);
+
+        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+        brelse(sinfo.bh);
+        if (IS_ERR(inode)) {
+                err = PTR_ERR(inode);
+                /* the directory was completed, just return a error */
+                goto out;
+        }
+        inode->i_version++;
+        inode->i_nlink = 2;
+        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+        dentry->d_time = dentry->d_parent->d_inode->i_version;
+        d_instantiate(dentry, inode);
+
+        unlock_super(sb);
+        return 0;
+
+out_free:
+        fat_free_clusters(dir, cluster);
+out:
+        unlock_super(sb);
+        return err;
+}
+
+static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
+                       struct inode *new_dir, struct dentry *new_dentry)
+{
+        struct buffer_head *dotdot_bh;
+        struct msdos_dir_entry *dotdot_de;
+        struct inode *old_inode, *new_inode;
+        struct fat_slot_info old_sinfo, sinfo;
+        struct timespec ts;
+        loff_t dotdot_i_pos, new_i_pos;
+        int err, is_dir, update_dotdot, corrupt = 0;
+        struct super_block *sb = old_dir->i_sb;
+
+        old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
+        old_inode = old_dentry->d_inode;
+        new_inode = new_dentry->d_inode;
+        lock_super(sb);
+        err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
+        if (err)
+                goto out;
+
+        is_dir = S_ISDIR(old_inode->i_mode);
+        update_dotdot = (is_dir && old_dir != new_dir);
+        if (update_dotdot) {
+                if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
+                                         &dotdot_i_pos) < 0) {
+                        err = -EIO;
+                        goto out;
+                }
+        }
+
+        ts = CURRENT_TIME_SEC;
+        if (new_inode) {
+                if (is_dir) {
+                        err = fat_dir_empty(new_inode);
+                        if (err)
+                                goto out;
+                }
+                new_i_pos = MSDOS_I(new_inode)->i_pos;
+                fat_detach(new_inode);
+        } else {
+                err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
+                                     &ts, &sinfo);
+                if (err)
+                        goto out;
+                new_i_pos = sinfo.i_pos;
+        }
+        new_dir->i_version++;
+
+        fat_detach(old_inode);
+        fat_attach(old_inode, new_i_pos);
+        if (IS_DIRSYNC(new_dir)) {
+                err = fat_sync_inode(old_inode);
+                if (err)
+                        goto error_inode;
+        } else
+                mark_inode_dirty(old_inode);
+
+        if (update_dotdot) {
+                int start = MSDOS_I(new_dir)->i_logstart;
+                dotdot_de->start = cpu_to_le16(start);
+                dotdot_de->starthi = cpu_to_le16(start >> 16);
+                mark_buffer_dirty(dotdot_bh);
+                if (IS_DIRSYNC(new_dir)) {
+                        err = sync_dirty_buffer(dotdot_bh);
+                        if (err)
+                                goto error_dotdot;
+                }
+                drop_nlink(old_dir);
+                if (!new_inode)
+                        inc_nlink(new_dir);
+        }
+
+        err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
+        old_sinfo.bh = NULL;
+        if (err)
+                goto error_dotdot;
+        old_dir->i_version++;
+        old_dir->i_ctime = old_dir->i_mtime = ts;
+        if (IS_DIRSYNC(old_dir))
+                (void)fat_sync_inode(old_dir);
+        else
+                mark_inode_dirty(old_dir);
+
+        if (new_inode) {
+                drop_nlink(new_inode);
+                if (is_dir)
+                        drop_nlink(new_inode);
+                new_inode->i_ctime = ts;
+        }
+out:
+        brelse(sinfo.bh);
+        brelse(dotdot_bh);
+        brelse(old_sinfo.bh);
+        unlock_super(sb);
+
+        return err;
+
+error_dotdot:
+        /* data cluster is shared, serious corruption */
+        corrupt = 1;
+
+        if (update_dotdot) {
+                int start = MSDOS_I(old_dir)->i_logstart;
+                dotdot_de->start = cpu_to_le16(start);
+                dotdot_de->starthi = cpu_to_le16(start >> 16);
+                mark_buffer_dirty(dotdot_bh);
+                corrupt |= sync_dirty_buffer(dotdot_bh);
+        }
+error_inode:
+        fat_detach(old_inode);
+        fat_attach(old_inode, old_sinfo.i_pos);
+        if (new_inode) {
+                fat_attach(new_inode, new_i_pos);
+                if (corrupt)
+                        corrupt |= fat_sync_inode(new_inode);
+        } else {
+                /*
+                 * If new entry was not sharing the data cluster, it
+                 * shouldn't be serious corruption.
+                 */
+                int err2 = fat_remove_entries(new_dir, &sinfo);
+                if (corrupt)
+                        corrupt |= err2;
+                sinfo.bh = NULL;
+        }
+        if (corrupt < 0) {
+                fat_fs_panic(new_dir->i_sb,
+                             "%s: Filesystem corrupted (i_pos %lld)",
+                             __func__, sinfo.i_pos);
+        }
+        goto out;
+}
+
+static const struct inode_operations vfat_dir_inode_operations = {
+        .create         = vfat_create,
+        .lookup         = vfat_lookup,
+        .unlink         = vfat_unlink,
+        .mkdir          = vfat_mkdir,
+        .rmdir          = vfat_rmdir,
+        .rename         = vfat_rename,
+        .setattr        = fat_setattr,
+        .getattr        = fat_getattr,
+};
+
+static int vfat_fill_super(struct super_block *sb, void *data, int silent)
+{
+        int res;
+
+        res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
+        if (res)
+                return res;
+
+        if (MSDOS_SB(sb)->options.name_check != 's')
+                sb->s_root->d_op = &vfat_ci_dentry_ops;
+        else
+                sb->s_root->d_op = &vfat_dentry_ops;
+
+        return 0;
+}
+
+static int vfat_get_sb(struct file_system_type *fs_type,
+                       int flags, const char *dev_name,
+                       void *data, struct vfsmount *mnt)
+{
+        return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super,
+                           mnt);
+}
+
+static struct file_system_type vfat_fs_type = {
+        .owner          = THIS_MODULE,
+        .name           = "vfat",
+        .get_sb         = vfat_get_sb,
+        .kill_sb        = kill_block_super,
+        .fs_flags       = FS_REQUIRES_DEV,
+};
+
+static int __init init_vfat_fs(void)
+{
+        return register_filesystem(&vfat_fs_type);
+}
+
+static void __exit exit_vfat_fs(void)
+{
+        unregister_filesystem(&vfat_fs_type);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("VFAT filesystem support");
+MODULE_AUTHOR("Gordon Chaffee");
+
+module_init(init_vfat_fs)
+module_exit(exit_vfat_fs)