linux/fs/vfat/namei.c
Joe Peterson b271e067c8 fatfs: add UTC timestamp option
Provide a new mount option ("tz=UTC") for DOS (vfat/msdos) filesystems,
allowing timestamps to be in coordinated universal time (UTC) rather than
local time in applications where doing this is advantageous.

In particular, portable devices that use fat/vfat (such as digital
cameras) can benefit from using UTC in their internal clocks, thus
avoiding daylight saving time errors and general time ambiguity issues.
The user of the device does not have to worry about changing the time when
moving from place or when daylight saving changes.

The new mount option, when set, disables the counter-adjustment that Linux
currently makes to FAT timestamp info in anticipation of the normal
userspace time zone correction.  When used in this new mode, all daylight
saving time and time zone handling is done in userspace as is normal for
many other filesystems (like ext3).  The default mode, which remains
unchanged, is still appropriate when mounting volumes written in Windows
(because of its use of local time).

I originally based this patch on one submitted last year by Paul Collins,
but I updated it to work with current source and changed variable/option
naming.  Ogawa Hirofumi (who maintains these filesystems) and I discussed
this patch at length on lkml, and he suggested using the option name in
the attached version of the patch.  Barry Bouwsma pointed out a good
addition to the patch as well.

Signed-off-by: Joe Peterson <joe@skyrush.com>
Signed-off-by: Paul Collins <paul@ondioline.org>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Barry Bouwsma <free_beer_for_all@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:34 -07:00

1055 lines
24 KiB
C

/*
* 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/msdos_fs.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/namei.h>
static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd)
{
int ret = 1;
if (!dentry->d_inode &&
nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_CREATE))
/*
* negative dentry is dropped, in order to make sure
* to use the name which a user desires if this is
* create path.
*/
ret = 0;
else {
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;
}
/* 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_dentry_ops[4] = {
{
.d_hash = vfat_hashi,
.d_compare = vfat_cmpi,
},
{
.d_revalidate = vfat_revalidate,
.d_hash = vfat_hashi,
.d_compare = vfat_cmpi,
},
{
.d_hash = vfat_hash,
.d_compare = vfat_cmp,
},
{
.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;
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_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.tz_utc);
de->time = de->ctime = time;
de->date = de->cdate = de->adate = date;
de->ctime_cs = 0;
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 = NULL;
struct dentry *alias;
int err, table;
lock_super(sb);
table = (MSDOS_SB(sb)->options.name_check == 's') ? 2 : 0;
dentry->d_op = &vfat_dentry_ops[table];
err = vfat_find(dir, &dentry->d_name, &sinfo);
if (err) {
table++;
goto error;
}
inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
brelse(sinfo.bh);
if (IS_ERR(inode)) {
unlock_super(sb);
return ERR_CAST(inode);
}
alias = d_find_alias(inode);
if (alias) {
if (d_invalidate(alias) == 0)
dput(alias);
else {
iput(inode);
unlock_super(sb);
return alias;
}
}
error:
unlock_super(sb);
dentry->d_op = &vfat_dentry_ops[table];
dentry->d_time = dentry->d_parent->d_inode->i_version;
dentry = d_splice_alias(inode, dentry);
if (dentry) {
dentry->d_op = &vfat_dentry_ops[table];
dentry->d_time = dentry->d_parent->d_inode->i_version;
}
return dentry;
}
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_dentry_ops[0];
else
sb->s_root->d_op = &vfat_dentry_ops[2];
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)