[dm-devel] [PATCH 5/7] multipath-tools: avoid access to /etc/localtime

[mwilck at suse.com]

From: Martin Wilck <mwilck at suse.com>

If the root file system is multipathed, and IO is queued because all paths
are failed, multipathd may block trying to access the root FS, and thus be
unable to reinstate paths. One file that is frequently accessed is
/etc/localtime. Avoid that by printing monotonic timestamps instead.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 libmultipath/debug.c     | 14 ++++++++------
 libmultipath/devmapper.c | 12 ++++++------
 libmultipath/log.c       |  1 -
 multipathd/main.c        |  3 ---
 4 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/libmultipath/debug.c b/libmultipath/debug.c
index 429f269..510e15e 100644
--- a/libmultipath/debug.c
+++ b/libmultipath/debug.c
@@ -14,6 +14,8 @@
 #include "config.h"
 #include "defaults.h"
 #include "debug.h"
+#include "time-util.h"
+#include "util.h"
 
 int logsink;
 int libmp_verbosity = DEFAULT_VERBOSITY;
@@ -25,13 +27,13 @@ void dlog(int prio, const char * fmt, ...)
 	va_start(ap, fmt);
 	if (logsink != LOGSINK_SYSLOG) {
 		if (logsink == LOGSINK_STDERR_WITH_TIME) {
-			time_t t = time(NULL);
-			struct tm *tb = localtime(&t);
-			char buff[16];
+			struct timespec ts;
+			char buff[32];
 
-			strftime(buff, sizeof(buff),
-				 "%b %d %H:%M:%S", tb);
-			buff[sizeof(buff)-1] = '\0';
+			get_monotonic_time(&ts);
+			safe_sprintf(buff, "%ld.%06ld",
+				     (long)ts.tv_sec,
+				     ts.tv_nsec/1000);
 			fprintf(stderr, "%s | ", buff);
 		}
 		vfprintf(stderr, fmt, ap);
diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 4977b31..095cbc0 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -27,6 +27,7 @@
 #include "config.h"
 #include "wwids.h"
 #include "version.h"
+#include "time-util.h"
 
 #include "log_pthread.h"
 #include <sys/types.h>
@@ -106,13 +107,12 @@ dm_write_log (int level, const char *file, int line, const char *f, ...)
 	va_start(ap, f);
 	if (logsink != LOGSINK_SYSLOG) {
 		if (logsink == LOGSINK_STDERR_WITH_TIME) {
-			time_t t = time(NULL);
-			struct tm *tb = localtime(&t);
-			char buff[16];
-
-			strftime(buff, sizeof(buff), "%b %d %H:%M:%S", tb);
-			buff[sizeof(buff)-1] = '\0';
+			struct timespec ts;
+			char buff[32];
 
+			get_monotonic_time(&ts);
+			safe_sprintf(buff, "%ld.%06ld",
+				     (long)ts.tv_sec, ts.tv_nsec/1000);
 			fprintf(stderr, "%s | ", buff);
 		}
 		fprintf(stderr, "libdevmapper: %s(%i): ", file, line);
diff --git a/libmultipath/log.c b/libmultipath/log.c
index 95c8f01..6498c88 100644
--- a/libmultipath/log.c
+++ b/libmultipath/log.c
@@ -120,7 +120,6 @@ void log_reset (char *program_name)
 	pthread_cleanup_push(cleanup_mutex, &logq_lock);
 
 	closelog();
-	tzset();
 	openlog(program_name, 0, LOG_DAEMON);
 
 	pthread_cleanup_pop(1);
diff --git a/multipathd/main.c b/multipathd/main.c
index b6a5f5b..28c147b 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -2710,9 +2710,6 @@ reconfigure (struct vectors * vecs)
 	delete_all_foreign();
 
 	reset_checker_classes();
-	/* Re-read any timezone changes */
-	tzset();
-
 	if (bindings_read_only)
 		conf->bindings_read_only = bindings_read_only;
 	check_alias_settings(conf);
-- 
2.29.0