Hi Hannes,
hare@xxxxxxx (Hannes Reinecke) writes:
> This adds a new SPC-3 ALUA hardware handler for multipathing.
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
<snip>
> +#define TPGS_STATE_OPTIMIZED 0x0
> +#define TPGS_STATE_NONOPTIMIZED 0x1
> +#define TPGS_STATE_STANDBY 0x2
> +#define TPGS_STATE_UNAVAILABLE 0x3
> +#define TPGS_STATE_OFFLINE 0xe
SPC-3 (at least the draft, rev 23 I'm looking at) doesn't know an
'Offline' state - I think it's a SPC-4 feature. So maybe 'Unavailable'
should be interpreted as path failure as well / instead?
<snip>
> +/*
> + * SET TARGET GROUP STATES endio handler
> + *
> + * We only have to test here if we should resubmit the command;
> + * any other error is assumed as a failure.
> + * Maybe we should analyze the sensebuffer here, too.
> + */
> +static void stpg_endio(struct request *req, int error)
> +{
> + struct hw_handler *hwh = req->end_io_data;
> + struct alua_handler *h = hwh->context;
> +
> + switch(host_byte(error)) {
> + case DID_BUS_BUSY:
> + if (!h->retry)
> + break;
> + h->retry--;
> + case DID_REQUEUE:
> + case DID_IMM_RETRY:
> + dm_enqueue_hw_workq(hwh);
> + goto done;
> + }
> +
> + if (had_failures(req, error)) {
> + if (h->tpgs & TPGS_MODE_IMPLICIT) {
> + /* Ignore errors; the array will figure it out */
> + DMWARN("%s: stpg failed %x, disabling explicit mode",
> + h->path->dev->name, error);
> + h->tpgs &= ~TPGS_MODE_EXPLICIT;
> + dm_enqueue_hw_workq(hwh);
> + } else {
> + DMWARN("%s: stpg failed %x, disable path",
> + h->path->dev->name, error);
> + dm_pg_init_complete(h->path, MP_FAIL_PATH);
> + }
> + } else {
> + DMWARN("%s: port group %02x new state %c",
> + h->path->dev->name, h->group_id,
> + print_alua_state(h->state) );
> + dm_pg_init_complete(h->path, 0);
Hmmm, maybe I'm just missing something so CMIIW, but I think the PG
state should be retrieved once more before finally calling
dm_pg_init_complete(), because the target might return the STPG command
before the transition has completed (SPC-3, 6.31). This could confuse
application clients?
Arne
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