NFSD: Fix nfsdcld warning

Since CONFIG_NFSD_LEGACY_CLIENT_TRACKING is a new config option, its
initial default setting should have been Y (if we are to follow the
common practice of "default Y, wait, default N, wait, remove code").

Paul also suggested adding a clearer remedy action to the warning
message.

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Message-Id: <d2ab4ee7-ba0f-44ac-b921-90c8fa5a04d2@molgen.mpg.de>
Fixes: 74fd487 ("nfsd: new Kconfig option for legacy client tracking")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: chucklever

fs/nfsd/Kconfig

@@ -162,7 +162,7 @@ config NFSD_V4_SECURITY_LABEL
 config NFSD_LEGACY_CLIENT_TRACKING
 	bool "Support legacy NFSv4 client tracking methods (DEPRECATED)"
 	depends on NFSD_V4
-	default n
+	default y
 	help
 	  The NFSv4 server needs to store a small amount of information on
 	  stable storage in order to handle state recovery after reboot. Most

fs/nfsd/nfs4recover.c

@@ -2086,8 +2086,8 @@ nfsd4_client_tracking_init(struct net *net)
 	status = nn->client_tracking_ops->init(net);
 out:
 	if (status) {
-		printk(KERN_WARNING "NFSD: Unable to initialize client "
-				    "recovery tracking! (%d)\n", status);
+		pr_warn("NFSD: Unable to initialize client recovery tracking! (%d)\n", status);
+		pr_warn("NFSD: Is nfsdcld running? If not, enable CONFIG_NFSD_LEGACY_CLIENT_TRACKING.\n");
 		nn->client_tracking_ops = NULL;
 	}
 	return status;