linux/fs/ufs/namei.c
Christian Brauner e18275ae55
fs: port ->rename() 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 09:24:26 +01:00

341 lines
7.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ufs/namei.c
*
* Migration to usage of "page cache" on May 2006 by
* Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
*
* Copyright (C) 1998
* Daniel Pirkl <daniel.pirkl@email.cz>
* Charles University, Faculty of Mathematics and Physics
*
* from
*
* linux/fs/ext2/namei.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/namei.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
#include <linux/time.h>
#include <linux/fs.h>
#include "ufs_fs.h"
#include "ufs.h"
#include "util.h"
static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = ufs_add_link(dentry, inode);
if (!err) {
d_instantiate_new(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
discard_new_inode(inode);
return err;
}
static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
{
struct inode * inode = NULL;
ino_t ino;
if (dentry->d_name.len > UFS_MAXNAMLEN)
return ERR_PTR(-ENAMETOOLONG);
ino = ufs_inode_by_name(dir, &dentry->d_name);
if (ino)
inode = ufs_iget(dir->i_sb, ino);
return d_splice_alias(inode, dentry);
}
/*
* By the time this is called, we already have created
* the directory cache entry for the new file, but it
* is so far negative - it has no inode.
*
* If the create succeeds, we fill in the inode information
* with d_instantiate().
*/
static int ufs_create (struct mnt_idmap * idmap,
struct inode * dir, struct dentry * dentry, umode_t mode,
bool excl)
{
struct inode *inode;
inode = ufs_new_inode(dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);
inode->i_op = &ufs_file_inode_operations;
inode->i_fop = &ufs_file_operations;
inode->i_mapping->a_ops = &ufs_aops;
mark_inode_dirty(inode);
return ufs_add_nondir(dentry, inode);
}
static int ufs_mknod(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t rdev)
{
struct inode *inode;
int err;
if (!old_valid_dev(rdev))
return -EINVAL;
inode = ufs_new_inode(dir, mode);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, mode, rdev);
ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
mark_inode_dirty(inode);
err = ufs_add_nondir(dentry, inode);
}
return err;
}
static int ufs_symlink (struct mnt_idmap * idmap, struct inode * dir,
struct dentry * dentry, const char * symname)
{
struct super_block * sb = dir->i_sb;
int err;
unsigned l = strlen(symname)+1;
struct inode * inode;
if (l > sb->s_blocksize)
return -ENAMETOOLONG;
inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
return err;
if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
/* slow symlink */
inode->i_op = &page_symlink_inode_operations;
inode_nohighmem(inode);
inode->i_mapping->a_ops = &ufs_aops;
err = page_symlink(inode, symname, l);
if (err)
goto out_fail;
} else {
/* fast symlink */
inode->i_op = &simple_symlink_inode_operations;
inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
memcpy(inode->i_link, symname, l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
return ufs_add_nondir(dentry, inode);
out_fail:
inode_dec_link_count(inode);
discard_new_inode(inode);
return err;
}
static int ufs_link (struct dentry * old_dentry, struct inode * dir,
struct dentry *dentry)
{
struct inode *inode = d_inode(old_dentry);
int error;
inode->i_ctime = current_time(inode);
inode_inc_link_count(inode);
ihold(inode);
error = ufs_add_link(dentry, inode);
if (error) {
inode_dec_link_count(inode);
iput(inode);
} else
d_instantiate(dentry, inode);
return error;
}
static int ufs_mkdir(struct mnt_idmap * idmap, struct inode * dir,
struct dentry * dentry, umode_t mode)
{
struct inode * inode;
int err;
inode_inc_link_count(dir);
inode = ufs_new_inode(dir, S_IFDIR|mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_dir;
inode->i_op = &ufs_dir_inode_operations;
inode->i_fop = &ufs_dir_operations;
inode->i_mapping->a_ops = &ufs_aops;
inode_inc_link_count(inode);
err = ufs_make_empty(inode, dir);
if (err)
goto out_fail;
err = ufs_add_link(dentry, inode);
if (err)
goto out_fail;
d_instantiate_new(dentry, inode);
return 0;
out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
discard_new_inode(inode);
out_dir:
inode_dec_link_count(dir);
return err;
}
static int ufs_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode * inode = d_inode(dentry);
struct ufs_dir_entry *de;
struct page *page;
int err = -ENOENT;
de = ufs_find_entry(dir, &dentry->d_name, &page);
if (!de)
goto out;
err = ufs_delete_entry(dir, de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
inode_dec_link_count(inode);
err = 0;
out:
return err;
}
static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
{
struct inode * inode = d_inode(dentry);
int err= -ENOTEMPTY;
if (ufs_empty_dir (inode)) {
err = ufs_unlink(dir, dentry);
if (!err) {
inode->i_size = 0;
inode_dec_link_count(inode);
inode_dec_link_count(dir);
}
}
return err;
}
static int ufs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
struct dentry *old_dentry, struct inode *new_dir,
struct dentry *new_dentry, unsigned int flags)
{
struct inode *old_inode = d_inode(old_dentry);
struct inode *new_inode = d_inode(new_dentry);
struct page *dir_page = NULL;
struct ufs_dir_entry * dir_de = NULL;
struct page *old_page;
struct ufs_dir_entry *old_de;
int err = -ENOENT;
if (flags & ~RENAME_NOREPLACE)
return -EINVAL;
old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ufs_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ufs_dir_entry *new_de;
err = -ENOTEMPTY;
if (dir_de && !ufs_empty_dir(new_inode))
goto out_dir;
err = -ENOENT;
new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
if (!new_de)
goto out_dir;
ufs_set_link(new_dir, new_de, new_page, old_inode, 1);
new_inode->i_ctime = current_time(new_inode);
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
err = ufs_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (dir_de)
inode_inc_link_count(new_dir);
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
old_inode->i_ctime = current_time(old_inode);
ufs_delete_entry(old_dir, old_de, old_page);
mark_inode_dirty(old_inode);
if (dir_de) {
if (old_dir != new_dir)
ufs_set_link(old_inode, dir_de, dir_page, new_dir, 0);
else {
kunmap(dir_page);
put_page(dir_page);
}
inode_dec_link_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
put_page(dir_page);
}
out_old:
kunmap(old_page);
put_page(old_page);
out:
return err;
}
const struct inode_operations ufs_dir_inode_operations = {
.create = ufs_create,
.lookup = ufs_lookup,
.link = ufs_link,
.unlink = ufs_unlink,
.symlink = ufs_symlink,
.mkdir = ufs_mkdir,
.rmdir = ufs_rmdir,
.mknod = ufs_mknod,
.rename = ufs_rename,
};