From: Christoph Hellwig <firstname.lastname@example.org> To: Hannes Reinecke <email@example.com> Cc: Keith Busch <firstname.lastname@example.org>, Christoph Hellwig <email@example.com>, firstname.lastname@example.org, Sagi Grimberg <email@example.com> Subject: Re: [PATCH] nvme: always treat DNR status as no-retryable Date: Tue, 26 Nov 2019 17:39:22 +0100 [thread overview] Message-ID: <20191126163922.GA7946@lst.de> (raw) In-Reply-To: <firstname.lastname@example.org> On Tue, Nov 26, 2019 at 05:34:21PM +0100, Hannes Reinecke wrote: > On 11/26/19 5:15 PM, Keith Busch wrote: >> On Tue, Nov 26, 2019 at 02:37:49PM +0100, Hannes Reinecke wrote: >>> If the DNR bit is set in the command status we should not retry >>> the command, irrespective of what the actual status is. >>> So map it directly to BLK_STS_TARGET to inform upper layers to >>> not retry the command, not even on another path. >> >> Why can't a DNR error be path specific, like if I detach a namespace >> from one of the controllers? >> > I've discussed the very same question with Fred Knight, and according to > him the 'DNR' bit is _command_ specific, ie _this particular command_ > should not be retried. > Any eventual alternative path should not be considered. To quote from the spec: "Do Not Retry (DNR): If set to ‘1’, indicates that if the same command is re-submitted to any controller in the NVM subsystem, then that re-submitted command is expected to fail. If cleared to ‘0’, indicates that the same command may succeed if retried." So yes, we should generally not submit it on another path, which is in fact what we already do if you look at nvme_complete_rq and nvme_req_needs_retry. Besides not not needing the BLK_STS_TARGET remap that remap also is a horrible bad idea given that is loses way too much information. _______________________________________________ linux-nvme mailing list email@example.com http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2019-11-26 16:39 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-26 13:37 Hannes Reinecke 2019-11-26 16:15 ` Keith Busch 2019-11-26 16:34 ` Hannes Reinecke 2019-11-26 16:39 ` Christoph Hellwig [this message] 2019-11-26 16:22 ` Christoph Hellwig 2019-11-26 16:28 ` Hannes Reinecke
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