monotonic time for mount.cifs timeouts

Commit Message

Björn Jacke Aug. 24, 2010, 4:16 p.m. UTC

None

Patch

From 4e8d243b9b0a5eb7bf4619c4cddbd9d3a8f4eb2d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Jacke?= <[e-mail]>
Date: Tue, 24 Aug 2010 09:41:01 +0200
Subject: [PATCH 2/2] mount.cifs: use monotonic time for timeouts

this is especially important during the boot process, where the clock is often
being set initially and clock jumps are more common.
---
 mtab.c |   23 ++++++++++++++++++++---
 1 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/mtab.c b/mtab.c
index de1aabd..64e7250 100644
--- a/mtab.c
+++ b/mtab.c
@@ -39,6 +39,7 @@ 
 #include <stdlib.h>
 #include <signal.h>
 #include "mount.h"
+#include "config.h"
 
 
 /* Updating mtab ----------------------------------------------*/
@@ -60,6 +61,22 @@  setlkw_timeout (int sig __attribute__((unused))) {
      /* nothing, fcntl will fail anyway */
 }
 
+/* use monotonic time for timeouts */
+struct timeval
+mono_time(void) {
+	struct timeval ret;
+#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
+	struct timespec ts;
+	if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
+		ret.tv_sec = ts.tv_sec;
+		ret.tv_usec = ts.tv_nsec/1000;
+		return ret;
+	}
+#endif
+	gettimeofday(&ret,NULL);
+	return ret;
+}
+
 /* Remove lock file.  */
 void
 unlock_mtab (void) {
@@ -150,7 +167,7 @@  lock_mtab (void) {
 	}
 	close(i);
 
-	gettimeofday(&maxtime, NULL);
+	maxtime = mono_time();
 	maxtime.tv_sec += MOUNTLOCK_MAXTIME;
 
 	waittime.tv_sec = 0;
@@ -177,7 +194,7 @@  lock_mtab (void) {
 
 		if (lockfile_fd < 0) {
 			/* Strange... Maybe the file was just deleted? */
-			gettimeofday(&now, NULL);
+			now = mono_time();
 			if (errno == ENOENT && now.tv_sec < maxtime.tv_sec) {
 				we_created_lockfile = 0;
 				continue;
@@ -199,7 +216,7 @@  lock_mtab (void) {
 			(void) unlink(linktargetfile);
 		} else {
 			/* Someone else made the link. Wait. */
-			gettimeofday(&now, NULL);
+			now = mono_time();
 			if (now.tv_sec < maxtime.tv_sec) {
 				alarm(maxtime.tv_sec - now.tv_sec);
 				if (fcntl (lockfile_fd, F_SETLKW, &flock) == -1) {
-- 
1.7.1