multipath: don't set queue_if_no_path without multipathd

If multipathd is not running, when all paths to a device have failed, there's no way for them to automatically get restored. If the device is set to queue, whatever is accessing it will hang forever. This can lead to problems if it happens at boot-up. This patch unsets queue_if_no_path for all devices created when multipathd is not running. When multipathd starts, it will automatically get reset queue_if_no_path to the proper value. This new behaviour can be overridden using the new "-q" option to multipath.

This version of the patch contacts multipathd's client socket to tell if it's running.

Signed-off-by Benjamin Marzinski <[email protected]>

---
 libmultipath/config.h    |    1 +
 libmultipath/configure.c |   40 +++++++++++++++++++++++++++++++++++++++-
 multipath/main.c         |    8 ++++++--
 3 files changed, 46 insertions(+), 3 deletions(-)

Index: multipath-tools-110916/libmultipath/config.h
===================================================================

libmultipath/config.h +1 -0

@@ -92,6 +92,7 @@ struct config {
 	int attribute_flags;
 	int fast_io_fail;
 	unsigned int dev_loss;
+	int allow_queueing;
 	uid_t uid;
 	gid_t gid;
 	mode_t mode;

Index: multipath-tools-110916/libmultipath/configure.c
===================================================================

libmultipath/configure.c +39 -1

@@ -35,6 +35,7 @@
 #include "alias.h"
 #include "prio.h"
 #include "util.h"
+#include "uxsock.h"
 
 extern int
 setup_map (struct multipath * mpp, char * params, int params_size)

@@ -448,6 +449,34 @@ deadmap (struct multipath * mpp)
 	return 1; /* dead */
 }
 
+int check_daemon(void)
+{
+	int fd;
+	char *reply;
+	size_t len;
+	int ret = 0;
+
+	fd = ux_socket_connect(DEFAULT_SOCKET);
+	if (fd == -1)
+		return 0;
+
+	if (send_packet(fd, "show daemon", 12) != 0)
+		goto out;
+	if (recv_packet(fd, &reply, &len) != 0)
+		goto out;
+
+	if (strstr(reply, "shutdown"))
+		goto out_free;
+
+	ret = 1;
+
+out_free:
+	FREE(reply);
+out:
+	close(fd);
+	return ret;
+}
+
 extern int
 coalesce_paths (struct vectors * vecs, vector newmp, char * refwwid, int force_reload)
 {

@@ -555,7 +584,16 @@ coalesce_paths (struct vectors * vecs, v
 		if (r == DOMAP_DRY)
 			continue;
 
-		if (mpp->no_path_retry != NO_PATH_RETRY_UNDEF) {
+		if (!conf->daemon && !conf->allow_queueing && !check_daemon()) {
+			if (mpp->no_path_retry != NO_PATH_RETRY_UNDEF &&
+			    mpp->no_path_retry != NO_PATH_RETRY_FAIL)
+				condlog(3, "%s: multipathd not running, unset "
+					"queue_if_no_path feature", mpp->alias);
+			if (!dm_queue_if_no_path(mpp->alias, 0))
+				remove_feature(&mpp->features,
+					       "queue_if_no_path");
+		}
+		else if (mpp->no_path_retry != NO_PATH_RETRY_UNDEF) {
 			if (mpp->no_path_retry == NO_PATH_RETRY_FAIL) {
 				condlog(3, "%s: unset queue_if_no_path feature",
 					mpp->alias);

Index: multipath-tools-110916/multipath/main.c
===================================================================

multipath/main.c +6 -2

@@ -79,7 +79,7 @@ usage (char * progname)
 {
 	fprintf (stderr, VERSION_STRING);
 	fprintf (stderr, "Usage:\n");
-	fprintf (stderr, "  %s [-d] [-r] [-v lvl] [-p pol] [-b fil] [dev]\n", progname);
+	fprintf (stderr, "  %s [-d] [-r] [-v lvl] [-p pol] [-b fil] [-q] [dev]\n", progname);
 	fprintf (stderr, "  %s -l|-ll|-f [-v lvl] [-b fil] [dev]\n", progname);
 	fprintf (stderr, "  %s -F [-v lvl]\n", progname);
 	fprintf (stderr, "  %s -t\n", progname);

@@ -92,6 +92,7 @@ usage (char * progname)
 		"  -ll     show multipath topology (maximum info)\n" \
 		"  -f      flush a multipath device map\n" \
 		"  -F      flush all multipath device maps\n" \
+		"  -q      allow queue_if_no_path when multipathd is not running\n"\
 		"  -d      dry run, do not create or update devmaps\n" \
 		"  -t      dump internal hardware table\n" \
 		"  -r      force devmap reload\n" \

@@ -397,7 +398,7 @@ main (int argc, char *argv[])
 		condlog(0, "multipath tools need sysfs mounted");
 		exit(1);
 	}
-	while ((arg = getopt(argc, argv, ":dhl::FfM:v:p:b:Brt")) != EOF ) {
+	while ((arg = getopt(argc, argv, ":dhl::FfM:v:p:b:Brtq")) != EOF ) {
 		switch(arg) {
 		case 1: printf("optarg : %s\n",optarg);
 			break;

@@ -414,6 +415,9 @@ main (int argc, char *argv[])
 		case 'B':
 			conf->bindings_read_only = 1;
 			break;
+		case 'q':
+			conf->allow_queueing = 1;
+			break;
 		case 'd':
 			conf->dry_run = 1;
 			break;