qubes-linux-kernel/patches.suse/dm-mpath-no-partitions-feature

From: Hannes Reinecke <hare@suse.de>
Subject: Disable partitions scan for multipathed devices
References: bnc#402922,bnc#514767
Patch-mainline: not yet

When multipath devices are being used as disks for VM Guests
any partition scanning / setup should be done within the VM Guest,
not from host. So we need to switch off partitions scanning via
kpartx there.
For this I've implemented a new feature 'no_partitions' which
just serves as a notifier to kpartx to _not_ create partitions
on these devices.

Patch ported to SLES11.

Signed-off-by: Hannes Reinecke <hare@suse.de>

---
 drivers/md/dm-mpath.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -57,6 +57,8 @@ struct priority_group {
 	struct list_head pgpaths;
 };
 
+#define FEATURE_NO_PARTITIONS 1
+
 /* Multipath context */
 struct multipath {
 	struct list_head list;
@@ -83,6 +85,7 @@ struct multipath {
 	unsigned pg_init_retries;	/* Number of times to retry pg_init */
 	unsigned pg_init_count;		/* Number of times pg_init called */
	unsigned pg_init_delay_msecs;	/* Number of msecs before pg_init retry */
+	unsigned features;		/* Additional selected features */
 
 	struct work_struct process_queued_ios;
 	struct list_head queued_ios;
@@ -852,6 +855,10 @@ static int parse_features(struct arg_set
 			continue;
 		}
 
+		if (!strnicmp(param_name, MESG_STR("no_partitions"))) {
+			m->features |= FEATURE_NO_PARTITIONS;
+			continue;
+		}
 		if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
 		    (argc >= 1)) {
 			r = read_param(_params + 1, shift(as),
@@ -1486,11 +1493,14 @@ static int multipath_status(struct dm_ta
 	else {
 		DMEMIT("%u ", m->queue_if_no_path +
 			      (m->pg_init_retries > 0) * 2 +
-			      (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2);
+			      (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 +
+			      (m->features & FEATURE_NO_PARTITIONS));
 		if (m->queue_if_no_path)
 			DMEMIT("queue_if_no_path ");
 		if (m->pg_init_retries)
 			DMEMIT("pg_init_retries %u ", m->pg_init_retries);
+		if (m->features & FEATURE_NO_PARTITIONS)
+			DMEMIT("no_partitions ");
		if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
			DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
 	}