This patch introduces a 'default_hw_handler' feature for
dm-mpath. When specifying the feature 'default_hw_handler'
dm-multipath will be using the currently attached hardware
handler instead of trying to re-attach with the one
specified during table creation.
If no hardware handler is attached the specified hardware
handler will be used.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/md/dm-mpath.c | 25 ++++++++++++++++++++++---
1 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 6d3f2a8..c1ef41d 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -57,6 +57,7 @@ struct priority_group {
};
#define FEATURE_NO_PARTITIONS 1
+#define FEATURE_DEFAULT_HW_HANDLER 2
/* Multipath context */
struct multipath {
@@ -589,14 +590,24 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
if (m->hw_handler_name) {
struct request_queue *q = bdev_get_queue(p->path.dev->bdev);
+ const char *hw_handler_name = m->hw_handler_name;
- r = scsi_dh_attach(q, m->hw_handler_name);
+ if (m->features & FEATURE_DEFAULT_HW_HANDLER)
+ hw_handler_name = NULL;
+
+ r = scsi_dh_attach(q, hw_handler_name);
if (r == -EBUSY) {
/*
* Already attached to different hw_handler,
* try to reattach with correct one.
*/
scsi_dh_detach(q);
+ r = scsi_dh_attach(q, hw_handler_name);
+ } else if (r == -EINVAL) {
+ /*
+ * No hardware handler attached, use
+ * the specified one.
+ */
r = scsi_dh_attach(q, m->hw_handler_name);
}
@@ -761,7 +772,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
const char *arg_name;
static struct dm_arg _args[] = {
- {0, 6, "invalid number of feature args"},
+ {0, 7, "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"},
};
@@ -787,6 +798,11 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
continue;
}
+ if (!strcasecmp(arg_name, "default_hw_handler")) {
+ m->features |= FEATURE_DEFAULT_HW_HANDLER;
+ continue;
+ }
+
if (!strcasecmp(arg_name, "pg_init_retries") &&
(argc >= 1)) {
r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
@@ -1371,7 +1387,8 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
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->features & FEATURE_NO_PARTITIONS));
+ (m->features & FEATURE_NO_PARTITIONS) +
+ (m->features & FEATURE_DEFAULT_HW_HANDLER));
if (m->queue_if_no_path)
DMEMIT("queue_if_no_path ");
if (m->pg_init_retries)
@@ -1380,6 +1397,8 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
if (m->features & FEATURE_NO_PARTITIONS)
DMEMIT("no_partitions ");
+ if (m->features & FEATURE_DEFAULT_HW_HANDLER)
+ DMEMIT("default_hw_handler ");
}
if (!m->hw_handler_name || type == STATUSTYPE_INFO)
--
1.6.0.2
--
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