linux/fs/reiserfs/ioctl.c
Christian Brauner 01beba7957
fs: port inode_owner_or_capable() to 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 09:24:29 +01:00

222 lines
5.0 KiB
C

/*
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include "reiserfs.h"
#include <linux/time.h>
#include <linux/uaccess.h>
#include <linux/pagemap.h>
#include <linux/compat.h>
#include <linux/fileattr.h>
int reiserfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
if (!reiserfs_attrs(inode->i_sb))
return -ENOTTY;
fileattr_fill_flags(fa, REISERFS_I(inode)->i_attrs);
return 0;
}
int reiserfs_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
unsigned int flags = fa->flags;
int err;
reiserfs_write_lock(inode->i_sb);
err = -ENOTTY;
if (!reiserfs_attrs(inode->i_sb))
goto unlock;
err = -EOPNOTSUPP;
if (fileattr_has_fsx(fa))
goto unlock;
/*
* Is it quota file? Do not allow user to mess with it
*/
err = -EPERM;
if (IS_NOQUOTA(inode))
goto unlock;
if ((flags & REISERFS_NOTAIL_FL) && S_ISREG(inode->i_mode)) {
err = reiserfs_unpack(inode);
if (err)
goto unlock;
}
sd_attrs_to_i_attrs(flags, inode);
REISERFS_I(inode)->i_attrs = flags;
inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
err = 0;
unlock:
reiserfs_write_unlock(inode->i_sb);
return err;
}
/*
* reiserfs_ioctl - handler for ioctl for inode
* supported commands:
* 1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
* and prevent packing file (argument arg has t
* be non-zero)
* 2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
* 3) That's all for a while ...
*/
long reiserfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
int err = 0;
reiserfs_write_lock(inode->i_sb);
switch (cmd) {
case REISERFS_IOC_UNPACK:
if (S_ISREG(inode->i_mode)) {
if (arg)
err = reiserfs_unpack(inode);
} else
err = -ENOTTY;
break;
/*
* following two cases are taken from fs/ext2/ioctl.c by Remy
* Card (card@masi.ibp.fr)
*/
case REISERFS_IOC_GETVERSION:
err = put_user(inode->i_generation, (int __user *)arg);
break;
case REISERFS_IOC_SETVERSION:
if (!inode_owner_or_capable(&nop_mnt_idmap, inode)) {
err = -EPERM;
break;
}
err = mnt_want_write_file(filp);
if (err)
break;
if (get_user(inode->i_generation, (int __user *)arg)) {
err = -EFAULT;
goto setversion_out;
}
inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
setversion_out:
mnt_drop_write_file(filp);
break;
default:
err = -ENOTTY;
}
reiserfs_write_unlock(inode->i_sb);
return err;
}
#ifdef CONFIG_COMPAT
long reiserfs_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
/*
* These are just misnamed, they actually
* get/put from/to user an int
*/
switch (cmd) {
case REISERFS_IOC32_UNPACK:
cmd = REISERFS_IOC_UNPACK;
break;
case REISERFS_IOC32_GETVERSION:
cmd = REISERFS_IOC_GETVERSION;
break;
case REISERFS_IOC32_SETVERSION:
cmd = REISERFS_IOC_SETVERSION;
break;
default:
return -ENOIOCTLCMD;
}
return reiserfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
}
#endif
int reiserfs_commit_write(struct file *f, struct page *page,
unsigned from, unsigned to);
/*
* reiserfs_unpack
* Function try to convert tail from direct item into indirect.
* It set up nopack attribute in the REISERFS_I(inode)->nopack
*/
int reiserfs_unpack(struct inode *inode)
{
int retval = 0;
int index;
struct page *page;
struct address_space *mapping;
unsigned long write_from;
unsigned long blocksize = inode->i_sb->s_blocksize;
if (inode->i_size == 0) {
REISERFS_I(inode)->i_flags |= i_nopack_mask;
return 0;
}
/* ioctl already done */
if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
return 0;
}
/* we need to make sure nobody is changing the file size beneath us */
{
int depth = reiserfs_write_unlock_nested(inode->i_sb);
inode_lock(inode);
reiserfs_write_lock_nested(inode->i_sb, depth);
}
reiserfs_write_lock(inode->i_sb);
write_from = inode->i_size & (blocksize - 1);
/* if we are on a block boundary, we are already unpacked. */
if (write_from == 0) {
REISERFS_I(inode)->i_flags |= i_nopack_mask;
goto out;
}
/*
* we unpack by finding the page with the tail, and calling
* __reiserfs_write_begin on that page. This will force a
* reiserfs_get_block to unpack the tail for us.
*/
index = inode->i_size >> PAGE_SHIFT;
mapping = inode->i_mapping;
page = grab_cache_page(mapping, index);
retval = -ENOMEM;
if (!page) {
goto out;
}
retval = __reiserfs_write_begin(page, write_from, 0);
if (retval)
goto out_unlock;
/* conversion can change page contents, must flush */
flush_dcache_page(page);
retval = reiserfs_commit_write(NULL, page, write_from, write_from);
REISERFS_I(inode)->i_flags |= i_nopack_mask;
out_unlock:
unlock_page(page);
put_page(page);
out:
inode_unlock(inode);
reiserfs_write_unlock(inode->i_sb);
return retval;
}