GFS2: Fix permissions checking for setflags ioctl()

We should be checking for the ownership of the file for which
flags are being set, rather than just for write access.
Reported-by: NDan Rosenberg <dan.j.rosenberg@gmail.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/file.c

@@ -218,6 +218,11 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
 	if (error)
 		goto out_drop_write;
 
+	error = -EACCES;
+	if (!is_owner_or_cap(inode))
+		goto out;
+
+	error = 0;
 	flags = ip->i_diskflags;
 	new_flags = (flags & ~mask) | (reqflags & mask);
 	if ((new_flags ^ flags) == 0)
@@ -275,8 +280,10 @@ static int gfs2_set_flags(struct file *filp, u32 __user *ptr)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
 	u32 fsflags, gfsflags;
+
 	if (get_user(fsflags, ptr))
 		return -EFAULT;
+
 	gfsflags = fsflags_cvt(fsflags_to_gfs2, fsflags);
 	if (!S_ISDIR(inode->i_mode)) {
 		if (gfsflags & GFS2_DIF_INHERIT_JDATA)