From: Neil Brown <neilb@suse.de>
Date: Mon, 21 Jul 2008 01:11:20 +0000 (+1000)
Subject: sm-notify: perform DNS lookup in the background.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=25b8aab2899c953ff6156db28af062881d49d0fe;p=nfs-utils.git

sm-notify: perform DNS lookup in the background.

If an NFS server has no network connectivity when it reboots,
it will block in sm-notify waiting for DNS lookup for a potentially
large number of hosts.  This is not helpful and just annoys the
sysadmin.

So do the DNS lookup in the backgrounded phase of sm-notify,
before sending off the NOTIFY requests.  If hostname lookup fails,
just drop that host.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
index bb67c37..407c578 100644
--- a/utils/statd/sm-notify.c
+++ b/utils/statd/sm-notify.c
@@ -76,7 +76,7 @@ static int		log_syslog = 0;
 
 static unsigned int	nsm_get_state(int);
 static void		notify(void);
-static void		notify_host(int, struct nsm_host *);
+static int		notify_host(int, struct nsm_host *);
 static void		recv_reply(int);
 static void		backup_hosts(const char *, const char *);
 static void		get_hosts(const char *);
@@ -286,7 +286,13 @@ notify(void)
 			hp = hosts;
 			hosts = hp->next;
 
-			notify_host(sock, hp);
+			if (notify_host(sock, hp) < 0) {
+				unlink(hp->path);
+				free(hp->name);
+				free(hp->path);
+				free(hp);
+				continue;
+			}
 
 			/* Set the timeout for this call, using an
 			   exponential timeout strategy */
@@ -316,9 +322,10 @@ notify(void)
 }
 
 /*
- * Send notification to a single host
+ * Send notification to a single host.
+ * Return negative if we should give up on this host.
  */
-void
+int
 notify_host(int sock, struct nsm_host *host)
 {
 	static unsigned int	xid = 0;
@@ -331,6 +338,17 @@ notify_host(int sock, struct nsm_host *host)
 	if (!host->xid)
 		host->xid = xid++;
 
+	if (host->ai == NULL) {
+		host->ai = host_lookup(AF_UNSPEC, host->name);
+		if (host->ai == NULL) {
+			nsm_log(LOG_WARNING,
+				"%s doesn't seem to be a valid address,"
+				" skipped",
+				host->name);
+			return -1;
+		}
+	}
+
 	memset(msgbuf, 0, sizeof(msgbuf));
 	p = msgbuf;
 	*p++ = htonl(host->xid);
@@ -395,6 +413,8 @@ notify_host(int sock, struct nsm_host *host)
 	len = (p - msgbuf) << 2;
 
 	sendto(sock, msgbuf, len, 0, (struct sockaddr *) &dest, sizeof(dest));
+
+	return 0;
 }
 
 /*
@@ -504,7 +524,7 @@ backup_hosts(const char *dirname, const char *bakname)
 }
 
 /*
- * Get all entries from sm.bak and convert them to host names
+ * Get all entries from sm.bak and convert them to host entries
  */
 static void
 get_hosts(const char *dirname)
@@ -532,15 +552,6 @@ get_hosts(const char *dirname)
 		if (stat(path, &stb) < 0)
 			continue;
 
-		host->ai = host_lookup(AF_UNSPEC, de->d_name);
-		if (! host->ai) {
-			nsm_log(LOG_WARNING,
-				"%s doesn't seem to be a valid address, skipped",
-				de->d_name);
-			unlink(path);
-			continue;
-		}
-
 		host->last_used = stb.st_mtime;
 		host->timeout = NSM_TIMEOUT;
 		host->path = strdup(path);