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.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/md/dm-mpath.c | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 922a338..6d3f2a8 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -56,6 +56,8 @@ struct priority_group {
struct list_head pgpaths;
};

+#define FEATURE_NO_PARTITIONS 1
+
/* Multipath context */
struct multipath {
struct list_head list;
@@ -87,6 +89,7 @@ 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;
@@ -758,7 +761,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
const char *arg_name;

static struct dm_arg _args[] = {
- {0, 5, "invalid number of feature args"},
+ {0, 6, "invalid number of feature args"},
{1, 50, "pg_init_retries must be between 1 and 50"},
{0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
};
@@ -779,6 +782,11 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
continue;
}

+ if (!strcasecmp(arg_name, "no_partitions")) {
+ m->features |= FEATURE_NO_PARTITIONS;
+ continue;
+ }
+
if (!strcasecmp(arg_name, "pg_init_retries") &&
(argc >= 1)) {
r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
@@ -1362,13 +1370,16 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
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->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
+ if (m->features & FEATURE_NO_PARTITIONS)
+ DMEMIT("no_partitions ");
}

if (!m->hw_handler_name || type == STATUSTYPE_INFO)
--
1.6.0.2

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel