Thanks for the response.
If pg_init is intended to be called only once then problem is elsewhere.
During the pg_init, the activate_path is called. The activate_path calls scsi_dh_activate(then rdac_activate) which will set path state to active(h->state = RDAC_STATE_ACTIVE;). My understanding is, h->state is specific to each path. How does d-m sets h->state to RDAC_STATE_ACTIVE for all the paths available in the path group.
This is what happening in my case. On path group failure, d-m switches the path group initiates path group. It then selects the first path (in the path group) starts I/O. After exhausting the repeat_count it then selects the next path in the path group. Then rdac_prep_fn is called. This function finds h->state is still passive and fails the path which becomes unusable.
This function returns BLKPREP_KILL which is leading to fail failure.
static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
{
struct rdac_dh_data *h = get_rdac_data(sdev);
int ret = BLKPREP_OK;
if (h->state != RDAC_STATE_ACTIVE) {
ret = BLKPREP_KILL;
req->cmd_flags |= REQ_QUIET;
}
return ret;
}
This is my understanding so far. Please correct me if there is anything wrong.
-----Original Message-----
From: dm-devel-bounces@xxxxxxxxxx [mailto:dm-devel-bounces@xxxxxxxxxx] On Behalf Of Alasdair G Kergon
Sent: Monday, November 10, 2008 6:59 PM
To: device-mapper development
Cc: andmike@xxxxxxxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx
Subject: Re: DM does not activate the paths if there are more than one path in path group during failover
pg_init is a function intended to be called *once* when there is a switch to a new group of paths. It is not per-path initialisation.
Alasdair
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