[PATCH 1/2] mount.nfs: trust the exit status of "start_statd".

[NeilBrown <neilb@suse.com>]

If DNS service is particularly slow, nfs_probe_statd() can fail even
though rpc.statd is actually running.  This happens because rpc.statd
is single threaded and could be waiting longer for DNS than
nfs_probe_statd() will wait for it.

This causes problems when mount.nfs uses nfs_probe_statd() to see if
statd is running, as is needed for NFSv3.

Currently in these circumstances there are two possible outcomes.
1/ if systemd is in use, it will be told to start rpc-statd, which
   is already running so no change.
   mount.nfs will try pinging rpc.statd a few more times and could
   eventually give up and fail the mount.
   While slow DNS may well result in slow service, it shouldn't cause
   a mount attempt to fail.

2/ if systemd is not in use, a new rpc.statd will be started.  This
   can (and has) lead to a large number of rpc.statd processes running
   on the one machine.

This patch addresses the first scenario.  If START_STATD is run and
exits with a success status, mount.nfs assumes statd is running and
allows the mount to succeed.  A separate patch will address the other
scenario.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 utils/mount/network.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/utils/mount/network.c b/utils/mount/network.c
index 8a9bf1476d51..7240ca7bcdc4 100644
--- a/utils/mount/network.c
+++ b/utils/mount/network.c
@@ -794,6 +794,7 @@ int start_statd(void)
 	if (stat(START_STATD, &stb) == 0) {
 		if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
 			int cnt = STATD_TIMEOUT * 10;
+			int status = 0;
 			const struct timespec ts = {
 				.tv_sec = 0,
 				.tv_nsec = 100000000,
@@ -808,7 +809,10 @@ int start_statd(void)
 						progname, strerror(errno));
 				break;
 			default: /* parent */
-				waitpid(pid, NULL,0);
+				if (waitpid(pid, &status,0) == pid &&
+				    status == 0)
+					/* assume it worked */
+					return 1;
 				break;
 			}
 			while (1) {