From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: linux-scsi@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH] scsi_error: do not allow IO errors with certain ILLEGAL_REQUEST sense to be retryable
Date: Fri, 02 Dec 2011 15:04:51 -0600 [thread overview]
Message-ID: <1322859891.6920.111.camel@dabdike> (raw)
In-Reply-To: <1322857889-2623-1-git-send-email-snitzer@redhat.com>
On Fri, 2011-12-02 at 15:31 -0500, Mike Snitzer wrote:
> Thin provisioned LUNs from multiple array vendors have failed WRITE SAME
> (16) w/ UNMAP bit set with ILLEGAL_REQUEST sense. With additional sense
> 0x24 and 0x26 respectively.
>
> In both instances the target would always fail the CDB no matter how
> many retries were performed (permanent target failure rather than
> transient path failure). This resulted in mkfs.ext4's discard of a
> multipath device looping indefinitely while failing paths.
I don't quite understand this analysis. ILLEGAL_REQUEST currently
always returns SUCCESS from scsi_check_sense(). That return is
propagated up to scsi_decide_disposition() which causes I/O completion.
We do have another gate for ILLEGAL_REQUEST in scsi_io_completion()
which can retry, but only if it's downshifting the command from _10 to
_6 ... so I don't get where you think the looping is coming from ... the
net effect of your patch is to change the error passed on to the block
layer in blk_end_request() from -EIO to -EREMOTEIO. So it sounds like
if there is a retry problem it's above SCSI?
James
next prev parent reply other threads:[~2011-12-02 21:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-02 20:31 [PATCH] scsi_error: do not allow IO errors with certain ILLEGAL_REQUEST sense to be retryable Mike Snitzer
2011-12-02 21:04 ` James Bottomley [this message]
2011-12-02 22:04 ` Mike Snitzer
2011-12-06 21:07 ` [PATCH] " Martin K. Petersen
2011-12-06 21:27 ` Mike Snitzer
2011-12-06 22:03 ` Martin K. Petersen
2011-12-06 22:42 ` Mike Snitzer
2012-02-13 16:29 ` Mike Snitzer
2012-02-13 17:53 ` Martin K. Petersen
2012-02-13 18:13 ` Mike Snitzer
2012-02-13 18:59 ` Mike Snitzer
2012-02-13 19:16 ` Martin K. Petersen
2012-02-13 19:36 ` Mike Snitzer
2012-02-13 19:38 ` James Bottomley
2012-02-13 23:35 ` [PATCH v2] [SCSI] scsi_error: classify some ILLEGAL_REQUEST sense as a permanent TARGET_ERROR Mike Snitzer
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