linux-stable/fs/affs/namei.c
Christian Brauner 6c960e68aa
fs: port ->create() to pass mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:25 +01:00

584 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* 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"
#include <linux/exportfs.h>
typedef int (*toupper_t)(int);
/* 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(const struct dentry *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(dentry);
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(dentry, qstr, affs_toupper,
affs_nofilenametruncate(dentry));
}
static int
affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(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 *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
return __affs_compare_dentry(len, str, name, affs_toupper,
affs_nofilenametruncate(dentry));
}
static int
affs_intl_compare_dentry(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(dentry));
}
/*
* 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;
struct dentry *res;
pr_debug("%s(\"%pd\")\n", __func__, dentry);
affs_lock_dir(dir);
bh = affs_find_entry(dir, dentry);
if (IS_ERR(bh)) {
affs_unlock_dir(dir);
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);
}
res = d_splice_alias(inode, dentry);
if (!IS_ERR_OR_NULL(res))
res->d_fsdata = dentry->d_fsdata;
affs_unlock_dir(dir);
return res;
}
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 mnt_idmap *idmap, 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;
affs_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 user_namespace *mnt_userns, 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;
affs_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 user_namespace *mnt_userns, 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_nohighmem(inode);
inode->i_data.a_ops = &affs_symlink_aops;
inode->i_mode = S_IFLNK | 0777;
affs_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;
inode->i_size = i + 1;
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);
}
static 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;
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;
}
static int
affs_xrename(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_old = NULL;
struct buffer_head *bh_new = NULL;
int retval;
bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
if (!bh_old)
return -EIO;
bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
if (!bh_new) {
affs_brelse(bh_old);
return -EIO;
}
/* Remove old header from its parent directory. */
affs_lock_dir(old_dir);
retval = affs_remove_hash(old_dir, bh_old);
affs_unlock_dir(old_dir);
if (retval)
goto done;
/* Remove new header from its parent directory. */
affs_lock_dir(new_dir);
retval = affs_remove_hash(new_dir, bh_new);
affs_unlock_dir(new_dir);
if (retval)
goto done;
/* Insert old into the new directory with the new name. */
affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
affs_fix_checksum(sb, bh_old);
affs_lock_dir(new_dir);
retval = affs_insert_hash(new_dir, bh_old);
affs_unlock_dir(new_dir);
/* Insert new into the old directory with the old name. */
affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
affs_fix_checksum(sb, bh_new);
affs_lock_dir(old_dir);
retval = affs_insert_hash(old_dir, bh_new);
affs_unlock_dir(old_dir);
done:
mark_buffer_dirty_inode(bh_old, new_dir);
mark_buffer_dirty_inode(bh_new, old_dir);
affs_brelse(bh_old);
affs_brelse(bh_new);
return retval;
}
int affs_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
struct dentry *old_dentry, struct inode *new_dir,
struct dentry *new_dentry, unsigned int flags)
{
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
if (flags & RENAME_EXCHANGE)
return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
}
static struct dentry *affs_get_parent(struct dentry *child)
{
struct inode *parent;
struct buffer_head *bh;
bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
if (!bh)
return ERR_PTR(-EIO);
parent = affs_iget(child->d_sb,
be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
brelse(bh);
if (IS_ERR(parent))
return ERR_CAST(parent);
return d_obtain_alias(parent);
}
static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
u32 generation)
{
struct inode *inode;
if (!affs_validblock(sb, ino))
return ERR_PTR(-ESTALE);
inode = affs_iget(sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
return inode;
}
static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
affs_nfs_get_inode);
}
static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
affs_nfs_get_inode);
}
const struct export_operations affs_export_ops = {
.fh_to_dentry = affs_fh_to_dentry,
.fh_to_parent = affs_fh_to_parent,
.get_parent = affs_get_parent,
};
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,
};