From: Hannes Reinecke <hare@suse.de>
To: michaelc@cs.wisc.edu
Cc: linux-scsi@vger.kernel.org
Subject: Re: [PATCH 0/4] notify userspace of offline->running transitions (v2)
Date: Mon, 21 May 2012 13:50:15 +0200 [thread overview]
Message-ID: <4FBA2BF7.7070500@suse.de> (raw)
In-Reply-To: <1337317019-12001-1-git-send-email-michaelc@cs.wisc.edu>
On 05/18/2012 06:56 AM, michaelc@cs.wisc.edu wrote:
> The following patches were made over the misc branch of the scsi tree.
>
> The patches fix a issue where if the device is offlined or IO is
> failed due to fast_io_fail (fc) /recovery_tmo (iscsi) then comes
> back, apps do not have a way a nice way to figure out the state
> has transitioned to running. Apps have to either poll the sysfs state
> file or send a SG IO to figure it out. With the patch apps can listen
> for the KOBJ CHANGE event like some of them (at least udev does) do
> already.
>
> v2:
> - Rebased to misc.
>
In principle, yes.
However, when doing this, we're now sending 'CHANGE' uevents from
SCSI devices. With the potential of putting _quite_ some strain on udev.
Kay explicitely debarred me from using uevents for my SCSI sense
code handling stuff, on the grounds that the SCSI subsystem might
flood the netlink socket and thereby starving udev from handling
really important messages.
(Keeping in mind that Kay doesn't believe in multipathing. But even
so, he has a point. Even more so with him being the udev maintainer :-)
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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next prev parent reply other threads:[~2012-05-21 11:50 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-18 4:56 [PATCH 0/4] notify userspace of offline->running transitions (v2) michaelc
2012-05-18 4:56 ` [PATCH 1/4] SCSI: add new SDEV_TRANSPORT_OFFLINE state michaelc
2012-05-21 11:50 ` Hannes Reinecke
2012-05-18 4:56 ` [PATCH 2/4] SCSI, classes, mpt2sas: have scsi_internal_device_unblock take new state (v2) michaelc
2012-05-18 4:56 ` [PATCH 3/4] SCSI: remove old comment from block/unblock functions (v2) michaelc
2012-05-18 4:56 ` [PATCH 4/4] SCSI: send KOBJ_CHANGE when device is set to running v2 michaelc
2012-05-21 11:45 ` Hannes Reinecke
2012-05-21 15:32 ` Mike Christie
2012-05-21 15:46 ` Mike Christie
2012-05-21 11:50 ` Hannes Reinecke [this message]
2012-05-21 15:35 ` [PATCH 0/4] notify userspace of offline->running transitions (v2) Mike Christie
2012-05-21 16:49 ` Kay Sievers
2012-05-21 17:04 ` Mike Christie
2012-05-21 19:15 ` Kay Sievers
2012-05-22 13:33 ` Hannes Reinecke
2012-06-06 21:18 ` Mike Christie
2012-06-26 21:48 ` Mike Snitzer
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