NFS: Fabricate fscache server index key correctly

When fabricating a server index key for fscache, we should clear the index key
buffer before starting to fill it in, not in the middle.
Reported-by: James Pearson <james-p@moving-picture.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/fscache-index.c

@@ -74,11 +74,10 @@ static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
 	struct nfs_server_key *key = buffer;
 	uint16_t len = sizeof(struct nfs_server_key);
 
+	memset(key, 0, len);
 	key->nfsversion = clp->rpc_ops->version;
 	key->family = clp->cl_addr.ss_family;
 
-	memset(key, 0, len);
-
 	switch (clp->cl_addr.ss_family) {
 	case AF_INET:
 		key->port = sin->sin_port;