NFS: Treat ENETUNREACH errors as fatal in containers

Propagate the NFS_MOUNT_NETUNREACH_FATAL flag to work with the generic
NFS client. If the flag is set, the client will receive ENETDOWN and
ENETUNREACH errors from the RPC layer, and is expected to treat them as
being fatal.

Signed-off-by: Trond Myklebust <[e-mail]>
Reviewed-by: Jeff Layton <[e-mail]>
Tested-by: Jeff Layton <[e-mail]>
Acked-by: Chuck Lever <[e-mail]>

fs/nfs/client.c

···
 		args.flags |= RPC_CLNT_CREATE_NOPING;
 	if (test_bit(NFS_CS_REUSEPORT, &clp->cl_flags))
 		args.flags |= RPC_CLNT_CREATE_REUSEPORT;
+	if (test_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags))
+		args.flags |= RPC_CLNT_CREATE_NETUNREACH_FATAL;
 
 	if (!IS_ERR(clp->cl_rpcclient))
 		return 0;
···
 				ctx->timeo, ctx->retrans);
 	if (ctx->flags & NFS_MOUNT_NORESVPORT)
 		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
+
+	if (ctx->flags & NFS_MOUNT_NETUNREACH_FATAL)
+		__set_bit(NFS_CS_NETUNREACH_FATAL, &cl_init.init_flags);
 
 	/* Allocate or find a client reference we can use */
 	clp = nfs_get_client(&cl_init);

fs/nfs/nfs4client.c

···
 	__set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
 	if (test_bit(NFS_CS_PNFS, &cl_init->init_flags))
 		__set_bit(NFS_CS_PNFS, &clp->cl_flags);
+	if (test_bit(NFS_CS_NETUNREACH_FATAL, &cl_init->init_flags))
+		__set_bit(NFS_CS_NETUNREACH_FATAL, &clp->cl_flags);
 	/*
 	 * Set up the connection to the server before we add add to the
 	 * global list.

fs/nfs/nfs4proc.c

···
 		return -EBUSY;
 	case -NFS4ERR_NOT_SAME:
 		return -ENOTSYNC;
+	case -ENETDOWN:
+	case -ENETUNREACH:
+		break;
 	default:
 		dprintk("%s could not handle NFSv4 error %d\n",
 				__func__, -err);

include/linux/nfs_fs_sb.h

···
 #define NFS_CS_DS		7		/* - Server is a DS */
 #define NFS_CS_REUSEPORT	8		/* - reuse src port on reconnect */
 #define NFS_CS_PNFS		9		/* - Server used for pnfs */
+#define NFS_CS_NETUNREACH_FATAL	10		/* - ENETUNREACH errors are fatal */
 	struct sockaddr_storage	cl_addr;	/* server identifier */
 	size_t			cl_addrlen;
 	char *			cl_hostname;	/* hostname of server */

include/linux/sunrpc/clnt.h

···
 				cl_noretranstimeo: 1,/* No retransmit timeouts */
 				cl_autobind : 1,/* use getport() */
 				cl_chatty   : 1,/* be verbose */
-				cl_shutdown : 1;/* rpc immediate -EIO */
+				cl_shutdown : 1,/* rpc immediate -EIO */
+				cl_netunreach_fatal : 1;
+						/* Treat ENETUNREACH errors as fatal */
 	struct xprtsec_parms	cl_xprtsec;	/* transport security policy */
 
 	struct rpc_rtt *	cl_rtt;		/* RTO estimator data */
···
 #define RPC_CLNT_CREATE_SOFTERR		(1UL << 10)
 #define RPC_CLNT_CREATE_REUSEPORT	(1UL << 11)
 #define RPC_CLNT_CREATE_CONNECTED	(1UL << 12)
+#define RPC_CLNT_CREATE_NETUNREACH_FATAL	(1UL << 13)
 
 struct rpc_clnt *rpc_create(struct rpc_create_args *args);
 struct rpc_clnt	*rpc_bind_new_program(struct rpc_clnt *,

include/linux/sunrpc/sched.h

···
 #define RPC_TASK_MOVEABLE	0x0004		/* nfs4.1+ rpc tasks */
 #define RPC_TASK_NULLCREDS	0x0010		/* Use AUTH_NULL credential */
 #define RPC_CALL_MAJORSEEN	0x0020		/* major timeout seen */
+#define RPC_TASK_NETUNREACH_FATAL 0x0040	/* ENETUNREACH is fatal */
 #define RPC_TASK_DYNAMIC	0x0080		/* task was kmalloc'ed */
 #define	RPC_TASK_NO_ROUND_ROBIN	0x0100		/* send requests on "main" xprt */
 #define RPC_TASK_SOFT		0x0200		/* Use soft timeouts */

include/trace/events/sunrpc.h

···
 		{ RPC_TASK_MOVEABLE, "MOVEABLE" },			\
 		{ RPC_TASK_NULLCREDS, "NULLCREDS" },			\
 		{ RPC_CALL_MAJORSEEN, "MAJORSEEN" },			\
+		{ RPC_TASK_NETUNREACH_FATAL, "NETUNREACH_FATAL"},	\
 		{ RPC_TASK_DYNAMIC, "DYNAMIC" },			\
 		{ RPC_TASK_NO_ROUND_ROBIN, "NO_ROUND_ROBIN" },		\
 		{ RPC_TASK_SOFT, "SOFT" },				\

net/sunrpc/clnt.c

···
 		clnt->cl_discrtry = 1;
 	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 		clnt->cl_chatty = 1;
+	if (args->flags & RPC_CLNT_CREATE_NETUNREACH_FATAL)
+		clnt->cl_netunreach_fatal = 1;
 
 	return clnt;
 }
···
 	new->cl_noretranstimeo = clnt->cl_noretranstimeo;
 	new->cl_discrtry = clnt->cl_discrtry;
 	new->cl_chatty = clnt->cl_chatty;
+	new->cl_netunreach_fatal = clnt->cl_netunreach_fatal;
 	new->cl_principal = clnt->cl_principal;
 	new->cl_max_connect = clnt->cl_max_connect;
 	return new;
···
 		task->tk_flags |= RPC_TASK_TIMEOUT;
 	if (clnt->cl_noretranstimeo)
 		task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
+	if (clnt->cl_netunreach_fatal)
+		task->tk_flags |= RPC_TASK_NETUNREACH_FATAL;
 	atomic_inc(&clnt->cl_task_count);
 }
 
···
 	case -EPROTONOSUPPORT:
 		trace_rpcb_bind_version_err(task);
 		goto retry_timeout;
+	case -ENETDOWN:
+	case -ENETUNREACH:
+		if (task->tk_flags & RPC_TASK_NETUNREACH_FATAL)
+			break;
+		fallthrough;
 	case -ECONNREFUSED:		/* connection problems */
 	case -ECONNRESET:
 	case -ECONNABORTED:
 	case -ENOTCONN:
 	case -EHOSTDOWN:
-	case -ENETDOWN:
 	case -EHOSTUNREACH:
-	case -ENETUNREACH:
 	case -EPIPE:
 		trace_rpcb_unreachable_err(task);
 		if (!RPC_IS_SOFTCONN(task)) {
···
 
 	task->tk_status = 0;
 	switch (status) {
+	case -ENETDOWN:
+	case -ENETUNREACH:
+		if (task->tk_flags & RPC_TASK_NETUNREACH_FATAL)
+			break;
+		fallthrough;
 	case -ECONNREFUSED:
 	case -ECONNRESET:
 		/* A positive refusal suggests a rebind is needed. */
-		if (RPC_IS_SOFTCONN(task))
-			break;
 		if (clnt->cl_autobind) {
 			rpc_force_rebind(clnt);
+			if (RPC_IS_SOFTCONN(task))
+				break;
 			goto out_retry;
 		}
 		fallthrough;
 	case -ECONNABORTED:
-	case -ENETDOWN:
-	case -ENETUNREACH:
 	case -EHOSTUNREACH:
 	case -EPIPE:
 	case -EPROTO:
···
 	trace_rpc_call_status(task);
 	task->tk_status = 0;
 	switch(status) {
-	case -EHOSTDOWN:
 	case -ENETDOWN:
-	case -EHOSTUNREACH:
 	case -ENETUNREACH:
+		if (task->tk_flags & RPC_TASK_NETUNREACH_FATAL)
+			goto out_exit;
+		fallthrough;
+	case -EHOSTDOWN:
+	case -EHOSTUNREACH:
 	case -EPERM:
 		if (RPC_IS_SOFTCONN(task))
 			goto out_exit;