- 根目录:
- fs
- affs
- namei.c
/*
* linux/fs/affs/namei.c
*
* (c) 1996 Hans-Joachim Widmaier - Rewritten
*
* (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
*
* (C) 1991 Linus Torvalds - minix filesystem
*/
#include "affs.h"
typedef int (*toupper_t)(int);
static int affs_toupper(int ch);
static int affs_hash_dentry(const struct dentry *, struct qstr *);
static int affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name);
static int affs_intl_toupper(int ch);
static int affs_intl_hash_dentry(const struct dentry *, struct qstr *);
static int affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name);
const struct dentry_operations affs_dentry_operations = {
.d_hash = affs_hash_dentry,
.d_compare = affs_compare_dentry,
};
const struct dentry_operations affs_intl_dentry_operations = {
.d_hash = affs_intl_hash_dentry,
.d_compare = affs_intl_compare_dentry,
};
/* Simple toupper() for DOS\1 */
static int
affs_toupper(int ch)
{
return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
}
/* International toupper() for DOS\3 ("international") */
static int
affs_intl_toupper(int ch)
{
return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
&& ch <= 0xFE && ch != 0xF7) ?
ch - ('a' - 'A') : ch;
}
static inline toupper_t
affs_get_toupper(struct super_block *sb)
{
return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
affs_intl_toupper : affs_toupper;
}
/*
* Note: the dentry argument is the parent dentry.
*/
static inline int
__affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
{
const u8 *name = qstr->name;
unsigned long hash;
int retval;
u32 len;
retval = affs_check_name(qstr->name, qstr->len, notruncate);
if (retval)
return retval;
hash = init_name_hash();
len = min(qstr->len, AFFSNAMEMAX);
for (; len > 0; name++, len--)
hash = partial_name_hash(toupper(*name), hash);
qstr->hash = end_name_hash(hash);
return 0;
}
static int
affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(qstr, affs_toupper,
affs_nofilenametruncate(dentry));
}
static int
affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(qstr, affs_intl_toupper,
affs_nofilenametruncate(dentry));
}
static inline int __affs_compare_dentry(unsigned int len,
const char *str, const struct qstr *name, toupper_t toupper,
bool notruncate)
{
const u8 *aname = str;
const u8 *bname = name->name;
/*
* 'str' is the name of an already existing dentry, so the name
* must be valid. 'name' must be validated first.
*/
if (affs_check_name(name->name, name->len, notruncate))
return 1;
/*
* If the names are longer than the allowed 30 chars,
* the excess is ignored, so their length may differ.
*/
if (len >= AFFSNAMEMAX) {
if (name->len < AFFSNAMEMAX)
return 1;
len = AFFSNAMEMAX;
} else if (len != name->len)
return 1;
for (; len > 0; len--)
if (toupper(*aname++) != toupper(*bname++))
return 1;
return 0;
}
static int
affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
return __affs_compare_dentry(len, str, name, affs_toupper,
affs_nofilenametruncate(parent));
}
static int
affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
return __affs_compare_dentry(len, str, name, affs_intl_toupper,
affs_nofilenametruncate(parent));
}
/*
* NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
*/
static inline int
affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
{
const u8 *name = dentry->d_name.name;
int len = dentry->d_name.len;
if (len >= AFFSNAMEMAX) {
if (*name2 < AFFSNAMEMAX)
return 0;
len = AFFSNAMEMAX;
} else if (len != *name2)
return 0;
for (name2++; len > 0; len--)
if (toupper(*name++) != toupper(*name2++))
return 0;
return 1;
}
int
affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
{
toupper_t toupper = affs_get_toupper(sb);
u32 hash;
hash = len = min(len, AFFSNAMEMAX);
for (; len > 0; len--)
hash = (hash * 13 + toupper(*name++)) & 0x7ff;
return hash % AFFS_SB(sb)->s_hashsize;
}
static struct buffer_head *
affs_find_entry(struct inode *dir, struct dentry *dentry)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *bh;
toupper_t toupper = affs_get_toupper(sb);
u32 key;
pr_debug("%s(\"%pd\")\n", __func__, dentry);
bh = affs_bread(sb, dir->i_ino);
if (!bh)
return ERR_PTR(-EIO);
key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
for (;;) {
affs_brelse(bh);
if (key == 0)
return NULL;
bh = affs_bread(sb, key);
if (!bh)
return ERR_PTR(-EIO);
if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
return bh;
key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
}
}
struct dentry *
affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *bh;
struct inode *inode = NULL;
pr_debug("%s(\"%pd\")\n", __func__, dentry);
affs_lock_dir(dir);
bh = affs_find_entry(dir, dentry);
affs_unlock_dir(dir);
if (IS_ERR(bh))
return ERR_CAST(bh);
if (bh) {
u32 ino = bh->b_blocknr;
/* store the real header ino in d_fsdata for faster lookups */
dentry->d_fsdata = (void *)(long)ino;
switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
//link to dirs disabled
//case ST_LINKDIR:
case ST_LINKFILE:
ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
}
affs_brelse(bh);
inode = affs_iget(sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
}
d_add(dentry, inode);
return NULL;
}
int
affs_unlink(struct inode *dir, struct dentry *dentry)
{
pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
d_inode(dentry)->i_ino, dentry);
return affs_remove_header(dentry);
}
int
affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
{
struct super_block *sb = dir->i_sb;
struct inode *inode;
int error;
pr_debug("%s(%lu,\"%pd\",0%ho)\n",
__func__, dir->i_ino, dentry, mode);
inode = affs_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_mode = mode;
mode_to_prot(inode);
mark_inode_dirty(inode);
inode->i_op = &affs_file_inode_operations;
inode->i_fop = &affs_file_operations;
inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
&affs_aops_ofs : &affs_aops;
error = affs_add_entry(dir, inode, dentry, ST_FILE);
if (error) {
clear_nlink(inode);
iput(inode);
return error;
}
return 0;
}
int
affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
struct inode *inode;
int error;
pr_debug("%s(%lu,\"%pd\",0%ho)\n",
__func__, dir->i_ino, dentry, mode);
inode = affs_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_mode = S_IFDIR | mode;
mode_to_prot(inode);
inode->i_op = &affs_dir_inode_operations;
inode->i_fop = &affs_dir_operations;
error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
if (error) {
clear_nlink(inode);
mark_inode_dirty(inode);
iput(inode);
return error;
}
return 0;
}
int
affs_rmdir(struct inode *dir, struct dentry *dentry)
{
pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
d_inode(dentry)->i_ino, dentry);
return affs_remove_header(dentry);
}
int
affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *bh;
struct inode *inode;
char *p;
int i, maxlen, error;
char c, lc;
pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
__func__, dir->i_ino, dentry, symname);
maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
inode = affs_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_op = &affs_symlink_inode_operations;
inode->i_data.a_ops = &affs_symlink_aops;
inode->i_mode = S_IFLNK | 0777;
mode_to_prot(inode);
error = -EIO;
bh = affs_bread(sb, inode->i_ino);
if (!bh)
goto err;
i = 0;
p = (char *)AFFS_HEAD(bh)->table;
lc = '/';
if (*symname == '/') {
struct affs_sb_info *sbi = AFFS_SB(sb);
while (*symname == '/')
symname++;
spin_lock(&sbi->symlink_lock);
while (sbi->s_volume[i]) /* Cannot overflow */
*p++ = sbi->s_volume[i++];
spin_unlock(&sbi->symlink_lock);
}
while (i < maxlen && (c = *symname++)) {
if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
*p++ = '/';
i++;
symname += 2;
lc = '/';
} else if (c == '.' && lc == '/' && *symname == '/') {
symname++;
lc = '/';
} else {
*p++ = c;
lc = c;
i++;
}
if (lc == '/')
while (*symname == '/')
symname++;
}
*p = 0;
mark_buffer_dirty_inode(bh, inode);
affs_brelse(bh);
mark_inode_dirty(inode);
error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
if (error)
goto err;
return 0;
err:
clear_nlink(inode);
mark_inode_dirty(inode);
iput(inode);
return error;
}
int
affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(old_dentry);
pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
dentry);
return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
}
int
affs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
struct super_block *sb = old_dir->i_sb;
struct buffer_head *bh = NULL;
int retval;
pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
retval = affs_check_name(new_dentry->d_name.name,
new_dentry->d_name.len,
affs_nofilenametruncate(old_dentry));
if (retval)
return retval;
/* Unlink destination if it already exists */
if (d_really_is_positive(new_dentry)) {
retval = affs_remove_header(new_dentry);
if (retval)
return retval;
}
bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
if (!bh)
return -EIO;
/* Remove header from its parent directory. */
affs_lock_dir(old_dir);
retval = affs_remove_hash(old_dir, bh);
affs_unlock_dir(old_dir);
if (retval)
goto done;
/* And insert it into the new directory with the new name. */
affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
affs_fix_checksum(sb, bh);
affs_lock_dir(new_dir);
retval = affs_insert_hash(new_dir, bh);
affs_unlock_dir(new_dir);
/* TODO: move it back to old_dir, if error? */
done:
mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
affs_brelse(bh);
return retval;
}