From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] dm-mpath: always return reservation conflict Date: Wed, 15 Jul 2015 13:56:09 +0200 Message-ID: <20150715115609.GA22391@lst.de> References: <1436959404-14035-1-git-send-email-hare@suse.de> <1436960108.31121.41.camel@HansenPartnership.com> <55A64980.3070304@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from verein.lst.de ([213.95.11.211]:47059 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751857AbbGOL4L (ORCPT ); Wed, 15 Jul 2015 07:56:11 -0400 Content-Disposition: inline In-Reply-To: <55A64980.3070304@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: James Bottomley , Mike Snitzer , dm-devel@redhat.com, linux-scsi@vger.kernel.org An array can't issue a reservation, the initiator needs to register it. Right now the only way to do it is through SG_IO passthrough, which is a best luck effort it I/O isn't also using SG_IO and can't be properly supported because of that. However I will submit an in-kernel reservation API soon which will allow us to have that sort of control. My current prototyp only allows for all-path reservations as I couldn't come up with a use case for per-path reservations, but if such a need should arise we can add it and take that into account in the multipathing code.