xfs: use mnt_want_write in compat_attrmulti ioctl

The compat version of the attrmulti ioctl needs to ask for and then
later release write access to the mount just like the native version,
otherwise we could potentially write to read-only mounts.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig 2009-01-19 02:03:03 +01:00 committed by Lachlan McIlroy
parent ab596ad897
commit 62e194ecda

View File

@ -17,6 +17,7 @@
*/
#include <linux/compat.h>
#include <linux/ioctl.h>
#include <linux/mount.h>
#include <asm/uaccess.h>
#include "xfs.h"
#include "xfs_fs.h"
@ -458,15 +459,23 @@ xfs_compat_attrmulti_by_handle(
&ops[i].am_length, ops[i].am_flags);
break;
case ATTR_OP_SET:
ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
if (ops[i].am_error)
break;
ops[i].am_error = xfs_attrmulti_attr_set(
dentry->d_inode, attr_name,
compat_ptr(ops[i].am_attrvalue),
ops[i].am_length, ops[i].am_flags);
mnt_drop_write(parfilp->f_path.mnt);
break;
case ATTR_OP_REMOVE:
ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
if (ops[i].am_error)
break;
ops[i].am_error = xfs_attrmulti_attr_remove(
dentry->d_inode, attr_name,
ops[i].am_flags);
mnt_drop_write(parfilp->f_path.mnt);
break;
default:
ops[i].am_error = EINVAL;