File 0005-mount-don-t-treat-temporary-name-resolution-failure-.patch of Package nfs-utils.3350

From c5de9ba602fd10a236a2ed80c46e896c11eed63f Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.com>
Date: Thu, 14 Jul 2016 11:11:25 +1000
Subject: [PATCH] mount: don't treat temporary name resolution failure as
 permanent.

If getaddrinfo() returns EAI_AGAIN, we shouldn't just give up, but
should continue normal retries as the nameserver may be unavailable
for the same reason as the NFS server.

So move the getaddrinfo() call from nfs_validate_options() into
nfs_try_mounts() which is always called soon after, except in the
'remount' case when we don't want it anyway.

If EAI_AGAIN is returned, set errno to EAGAIN and allow this to be a
temporary failure.  Otherwise report error and set errno to EALREADY
so no further message is given.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 utils/mount/stropts.c |   56 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 20 deletions(-)

--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -84,6 +84,7 @@ struct nfsmount_info {
 				*type;		/* "nfs" or "nfs4" */
 	char			*hostname;	/* server's hostname */
 	struct addrinfo		*address;	/* server's addresses */
+	sa_family_t		family;		/* Address family */
 
 	struct mount_options	*options;	/* parsed mount options */
 	char			**extra_opts;	/* string for /etc/mtab */
@@ -341,36 +342,24 @@ static int nfs_set_version(struct nfsmou
  */
 static int nfs_validate_options(struct nfsmount_info *mi)
 {
-	struct addrinfo hint = {
-		.ai_protocol	= (int)IPPROTO_UDP,
-	};
-	sa_family_t family;
-	int error;
-
 	if (!nfs_parse_devname(mi->spec, &mi->hostname, NULL))
 		return 0;
 
-	if (!nfs_nfs_proto_family(mi->options, &family))
-		return 0;
-
-	hint.ai_family = (int)family;
-	error = getaddrinfo(mi->hostname, NULL, &hint, &mi->address);
-	if (error != 0) {
-		nfs_error(_("%s: Failed to resolve server %s: %s"),
-			progname, mi->hostname, gai_strerror(error));
-		mi->address = NULL;
+	if (!nfs_nfs_proto_family(mi->options, &mi->family))
 		return 0;
-	}
 
 	if (!nfs_set_version(mi))
 		return 0;
 
 	if (!nfs_append_sloppy_option(mi->options))
 		return 0;
-
-	if (!nfs_append_addr_option(mi->address->ai_addr,
-					mi->address->ai_addrlen, mi->options))
-		return 0;
+	/*
+	 * A remount is not going to be able to change the server's address,
+	 * nor should we try to resolve another address for the server as we
+	 * may end up with a different address.
+	 * A non-remount will set 'addr' from ->hostname
+	 */
+	po_remove_all(mi->options, "addr");
 
 	return 1;
 }
@@ -840,6 +829,32 @@ static int nfs_try_mount(struct nfsmount
 {
 	int result = 0;
 
+	if (mi->address == NULL) {
+		struct addrinfo hint = {
+			.ai_protocol	= (int)IPPROTO_UDP,
+		};
+		int error;
+		struct addrinfo *address;
+
+		hint.ai_family = (int)mi->family;
+		error = getaddrinfo(mi->hostname, NULL, &hint, &address);
+		if (error != 0) {
+			if (error == EAI_AGAIN)
+				errno = EAGAIN;
+			else {
+				nfs_error(_("%s: Failed to resolve server %s: %s"),
+					  progname, mi->hostname, gai_strerror(error));
+				errno = EALREADY;
+			}
+			return 0;
+		}
+
+		if (!nfs_append_addr_option(address->ai_addr,
+					    address->ai_addrlen, mi->options))
+			return 0;
+		mi->address = address;
+	}
+
 	switch (mi->version) {
 	case 0:
 		result = nfs_autonegotiate(mi);
@@ -878,6 +893,7 @@ static int nfs_is_permanent_error(int er
 	case ETIMEDOUT:
 	case ECONNREFUSED:
 	case EHOSTUNREACH:
+	case EAGAIN:
 		return 0;	/* temporary */
 	default:
 		return 1;	/* permanent */