[dm-devel] [BUG] dm-mpath and scsi persistent reservation

[Christophe Varoqui <christophe varoqui free fr>]

Hi,

the dm-mpath multipathing driver enqueues write ios returned by
the scsi layer with a "reservation conflict" error (on assymetric
storage controllers, like Clariion, where queue_if_no_path is enabled).

This is wrong, and a potent data-corrupter : wio sent to a reserved
scsi device should never be retried on this same device.

Can someone advise on a viable solution for this problem ? I
understand the Device Mapper being a block remapper, it is not expected
to receive scsi errors directly ... but maybe some kind of translation
might be acceptable. Or is there hope in the request-based remapper ?

Jens, James, Alasdair, ... as maintainers of the involved subsystems,
would you care to give some advise on the issue.

Regards,
cvaroqui