WSL2-Linux-Kernel/fs/vfat/namei.c

1056 строки
24 KiB
C
Исходник Обычный вид История

/*
* 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);
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;
}
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:02:57 +04:00
static int vfat_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct vfsmount *mnt)
{
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 13:02:57 +04:00
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)