Re: [PATCH nfs-utils] Allow mountd to not listen for RPC calls when v2/v3 disabled

[Chuck Lever <chuck.lever@oracle.com>]

Hi Neil-

On 05/06/2010 03:11 AM, Neil Brown wrote:
>
> Mountd listens on 2 different versions for NFSv2 (MOUNTv1 and MOUNTv2)
> and one for NFSv3 (MOUNTv3)
>
> When --no-nfs-version requests an NFS version to be disabled, the
> code actually disabled the MOUNT version. This works is several cases,
> but requires --no-nfs-version 1 to completely disable NFSv2, which
> is wrong.
>
> So if we do disable 1, 2, and 3. mountd complain and won't run, it
> is not possible to run just v4 - i.e. not listening for MOUNT requests
> at all (as v4 doesn't need them).
>
> So change the handling of "--no-nfs-version 2" it disable MOUNTv1 as well as
> MOUNTv2, and allow mountd to continue running as long as one of
> NFSv2 NFSv3 NFSv4 is enabled.
>
> Signed-off-by: NeilBrown<neilb@suse.de>
>
> diff --git a/utils/mountd/mountd.c b/utils/mountd/mountd.c
> index a0a1f2d..5373d81 100644
> --- a/utils/mountd/mountd.c
> +++ b/utils/mountd/mountd.c
> @@ -80,10 +80,10 @@ static int nfs_version = -1;
>   static void
>   unregister_services (void)
>   {
> -	if (nfs_version&  0x1)
> +	if (nfs_version&  (0x1<<  1)) {
>   		pmap_unset (MOUNTPROG, MOUNTVERS);
> -	if (nfs_version&  (0x1<<  1))
>   		pmap_unset (MOUNTPROG, MOUNTVERS_POSIX);
> +	}
>   	if (nfs_version&  (0x1<<  2))
>   		pmap_unset (MOUNTPROG, MOUNTVERS_NFSV3);
>   }
> @@ -712,8 +712,10 @@ main(int argc, char **argv)
>   			usage(argv [0], 1);
>   		}
>
> -	/* No more arguments allowed. */
> -	if (optind != argc || !(nfs_version&  0x7))
> +	/* No more arguments allowed.
> +	 * Require at least one valid version (2, 3, or 4)
> +	 */
> +	if (optind != argc || !(nfs_version&  0xE))

IMO macros would be a little more explanatory than constant expressions 
like "0xE" and "0x1 << 2".

>   		usage(argv [0], 1);
>
>   	if (chdir(state_dir)) {
> @@ -761,12 +763,12 @@ main(int argc, char **argv)
>   	if (new_cache)
>   		cache_open();
>
> -	if (nfs_version&  0x1)
> +	if (nfs_version&  (0x1<<  1)) {

Jeff and I talked recently about disabling mountd's RPC listeners if 
only NFSv4 was desired.  I can't remember the details, but this is 
roughly what we thought was appropriate.  Jeff, was there another issue 
I'm not remembering?

>   		rpc_init("mountd", MOUNTPROG, MOUNTVERS,
>   			 mount_dispatch, port);
> -	if (nfs_version&  (0x1<<  1))
>   		rpc_init("mountd", MOUNTPROG, MOUNTVERS_POSIX,
>   			 mount_dispatch, port);
> +	}
>   	if (nfs_version&  (0x1<<  2))
>   		rpc_init("mountd", MOUNTPROG, MOUNTVERS_NFSV3,
>   			 mount_dispatch, port);

-- 
chuck[dot]lever[at]oracle[dot]com