xfs: XFS_DIFLAG_DAX is only for regular files or directories

Only file data can use DAX, so we should onyl be able to set this
flag on regular files. However, the flag also serves as an "inherit"
flag at file create time when set on directories, so limit the
FS_IOC_FSSETXATTR ioctl to only set this flag on regular files and
directories.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 478d04e07f9500d6ceed20231deb6b474161c708..ee8f66616cbb36e4fb2270fcaf3912375b704532 100644 (file)
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1051,6 +1051,14 @@ xfs_ioctl_setattr_xflags(
            !capable(CAP_LINUX_IMMUTABLE))
                return -EPERM;
 
+       /*
+        * It is only valid to set the DAX flag on regular files and
+        * directories. On directories it serves as an inherit hint.
+        */
+       if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
+           !(S_ISREG(VFS_I(ip)->i_mode) || S_ISDIR(VFS_I(ip)->i_mode)))
+               return -EINVAL;
+
        xfs_set_diflags(ip, fa->fsx_xflags);
        xfs_diflags_to_linux(ip);
        xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);