Date: Thu, 18 Nov 2010 19:11:49 -0800
From: Malahal Naineni <malahal@us.ibm.com>
To: Hannes Reinecke <hare@suse.de>
Cc: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>,
        Kiyoshi Ueda <k-ueda@ct.jp.nec.com>, michaelc@cs.wisc.edu,
        tytso@mit.edu, linux-scsi@vger.kernel.org,
        Mike Snitzer <snitzer@redhat.com>, jaxboe@fusionio.com, vst@vlnb.net,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
        linux-raid@vger.kernel.org, linux-ide@vger.kernel.org,
        device-mapper development <dm-devel@redhat.com>,
        James.Bottomley@suse.de, Sergei Shtylyov <sshtylyov@mvista.com>,
        konishi.ryusuke@lab.ntt.co.jp, linux-fsdevel@vger.kernel.org,
        jack@suse.cz, rwheeler@redhat.com, swhiteho@redhat.com,
        chris.mason@oracle.com, Tejun Heo <tj@kernel.org>
Subject: Re: [dm-devel] [RFC] training mpath to discern between SCSI errors
Message-ID: <20101119031149.GA28455@us.ibm.com>
Mail-Followup-To: Hannes Reinecke <hare@suse.de>,
	Jun'ichi Nomura <j-nomura@ce.jp.nec.com>,
	Kiyoshi Ueda <k-ueda@ct.jp.nec.com>, michaelc@cs.wisc.edu,
	tytso@mit.edu, linux-scsi@vger.kernel.org,
	Mike Snitzer <snitzer@redhat.com>, jaxboe@fusionio.com,
	vst@vlnb.net, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>, linux-raid@vger.kernel.org,
	linux-ide@vger.kernel.org,
	device-mapper development <dm-devel@redhat.com>,
	James.Bottomley@suse.de, Sergei Shtylyov <sshtylyov@mvista.com>,
	konishi.ryusuke@lab.ntt.co.jp, linux-fsdevel@vger.kernel.org,
	jack@suse.cz, rwheeler@redhat.com, swhiteho@redhat.com,
	chris.mason@oracle.com, Tejun Heo <tj@kernel.org>
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 <4C7B9F14.9080900@mvista.com>
 <4C7BA670.2060303@suse.de>
 <4C7BC5B4.3010707@suse.de>
 <4CBC00B3.7090603@ce.jp.nec.com>
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Hannes Reinecke [hare@suse.de] wrote:
> > Also (although this might be a bit off topic from your patch),
> > can we expand such a distinction to what should be logged?
> > Currently, it's difficult to distinguish important SCSI/block errors
> > and less important ones in kernel log.
> > For example, when I get a link failure on sda, kernel prints something
> > like below, regardless of whether the I/O is recovered by multipathing or not:
> >   end_request: I/O error, dev sda, sector XXXXX
> > 
> Indeed, when using the above we could be modifying the above
> message, eg by
> 
> end_request: transport error, dev sda, sector XXXXX
> 
> or
> 
> end_request: target error, dev sda, sector XXXXX
> 
> which would improve the output noticeable.
> 
> > Setting REQ_QUIET in dm-multipath could mask the message
> > but also other important ones in SCSI.
> > 
> Hmm. Not sure about that, but I think the above modifications will
> be useful already.
> 
> I'll be sending an updated patch.

Hannes, is there an updated version of this patch? It applied fine with
Linus git tree with a minor reject! I would like to test an updated
version if you have one (the update seems to refer to better logging
only, right?).

Thanks, Malahal.
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