From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH] sd: always retry READ CAPACITY for ALUA state transition Date: Tue, 28 Apr 2015 14:18:45 -0700 Message-ID: <1430255925.2181.16.camel@HansenPartnership.com> References: <1430127309-90412-1-git-send-email-hare@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from bedivere.hansenpartnership.com ([66.63.167.143]:34244 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965977AbbD1VSr (ORCPT ); Tue, 28 Apr 2015 17:18:47 -0400 In-Reply-To: <1430127309-90412-1-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: Christoph Hellwig , linux-scsi@vger.kernel.org On Mon, 2015-04-27 at 11:35 +0200, Hannes Reinecke wrote: > During ALUA state transitions the device might return > a sense code 02/04/0a (Logical unit not accessible, asymmetric > access state transition). As this is a transient error > we should just retry the READ CAPACITY call until > the state transition finishes and the correct > capacity can be returned. > > Signed-off-by: Hannes Reinecke > --- > drivers/scsi/sd.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 79beebf..7178b05 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -1987,6 +1987,11 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, > * give it one more chance */ > if (--reset_retries > 0) > continue; > + if (sense_valid && > + sshdr.sense_key == NOT_READY && > + sshdr.asc == 0x04 && sshdr.ascq == 0x0A) > + /* ALUA state transition; always retry */ > + continue; > } > retries--; > > @@ -2069,6 +2074,11 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp, > * give it one more chance */ > if (--reset_retries > 0) > continue; > + if (sense_valid && > + sshdr.sense_key == NOT_READY && > + sshdr.asc == 0x04 && sshdr.ascq == 0x0A) > + /* ALUA state transition; always retry */ > + continue; > } > retries--; > Got to say I really don't like this infinite retry possibility. How long does the ALUA transition take? Would increasing retries work (or even hijacking reset_retries)? James