The server is failing to apply the umask when creating new objects on
filesystems without ACL support.

To reproduce this, you need to use NFSv4.2 and a client and server
recent enough to support umask, and you need to export a filesystem that
lacks ACL support (for example, ext4 with the "noacl" mount option).

Filesystems with ACL support are expected to take care of the umask
themselves (usually by calling posix_acl_create).

For filesystems without ACL support, this is up to the caller of
vfs_create(), vfs_mknod(), or vfs_mkdir().
Reported-by: Elliott Mitchell <ehem+debian@m5p.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Fixes: 47057abd ("nfsd: add support for the umask attribute")
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>