Commit 60ea6812 authored Oct 17, 2013 by Chuck Lever Committed by Trond Myklebust Oct 28, 2013

NFS: Migration support for RELEASE_LOCKOWNER



Currently the Linux NFS client ignores the operation status code for
the RELEASE_LOCKOWNER operation.  Like NFSv3's UMNT operation,
RELEASE_LOCKOWNER is a courtesy to help servers manage their
resources, and the outcome is not consequential for the client.

During a migration, a server may report NFS4ERR_LEASE_MOVED, in
which case the client really should retry, since typically
LEASE_MOVED has nothing to do with the current operation, but does
prevent it from going forward.

Also, it's important for a client to respond as soon as possible to
a moved lease condition, since the client's lease could expire on
the destination without further action by the client.

NFS4ERR_DELAY is not included in the list of valid status codes for
RELEASE_LOCKOWNER in RFC 3530bis.  However, rfc3530-migration-update
does permit migration-capable servers to return DELAY to clients,
but only in the context of an ongoing migration.  In this case the
server has frozen lock state in preparation for migration, and a
client retry would help the destination server purge unneeded state
once migration recovery is complete.

Interestly, NFS4ERR_MOVED is not valid for RELEASE_LOCKOWNER, even
though lock owners can be migrated with Transparent State Migration.

Note that RFC 3530bis section 9.5 includes RELEASE_LOCKOWNER in the
list of operations that renew a client's lease on the server if they
succeed.  Now that our client pays attention to the operation's
status code, we can note that renewal appropriately.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

parent 8ef2f8d4

fs/nfs/nfs4proc.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -5800,6 +5800,7 @@ struct nfs_release_lockowner_data {
		struct nfs_release_lockowner_args args;
		struct nfs4_sequence_args seq_args;
		struct nfs4_sequence_res seq_res;
		unsigned long timestamp;
		};

		static void nfs4_release_lockowner_prepare(struct rpc_task task, void calldata)
		@@ -5807,12 +5808,27 @@ static void nfs4_release_lockowner_prepare(struct rpc_task task, void calldata
		struct nfs_release_lockowner_data *data = calldata;
		nfs40_setup_sequence(data->server,
		&data->seq_args, &data->seq_res, task);
		data->timestamp = jiffies;
		}

		static void nfs4_release_lockowner_done(struct rpc_task task, void calldata)
		{
		struct nfs_release_lockowner_data *data = calldata;
		struct nfs_server *server = data->server;

		nfs40_sequence_done(task, &data->seq_res);

		switch (task->tk_status) {
		case 0:
		renew_lease(server, data->timestamp);
		break;
		case -NFS4ERR_STALE_CLIENTID:
		case -NFS4ERR_EXPIRED:
		case -NFS4ERR_LEASE_MOVED:
		case -NFS4ERR_DELAY:
		if (nfs4_async_handle_error(task, server, NULL) == -EAGAIN)
		rpc_restart_call_prepare(task);
		}
		}

		static void nfs4_release_lockowner_release(void *calldata)