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From: sagi@grimberg.me (Sagi Grimberg)
Subject: [PATCH rfc 1/2] nvme: don't remove namespace if revalidate failed because of controller reset
Date: Wed, 31 Jul 2019 11:11:51 -0700	[thread overview]
Message-ID: <ef157a14-748b-08a1-b5e5-f5f9676988f7@grimberg.me> (raw)
In-Reply-To: <0e103ae2-b0b5-28e5-bfea-35d8f683809a@suse.de>


>> You are correct, this was why I had the ctrl->state check after
>> revalidate_disk so if it failed because we are in a reset we should
>> not remove the namespace.
>>
>> We need a reliable way to NOT remove the namespace if revalidate_disk
>> failed because the controller is resetting and we don't have a channel
>> to the controller at this very moment...
>>
> A similar thing is true for the 'ns_head' structure; I could easily
> envision a scenario where all paths are dropped (due to revalidate
> failures or whatnot) with all controllers in reset.

Hannes, paths should not be dropped in controller resets, only when
the controller is going away. Its simple as that.

> But as all paths are dropped struct ns_head doesn't have any reference
> to any namespaces (and consequently, to any controller), and will be
> failing all I/O before itself being removed.
> It will be re-created after resetting completes and all namespaces are
> re-attached, for sure, but it still means that we're getting I/O errors
> where we really shouldn't.

Paths should only be removed when the controller is going away, not when
it is temporarily disconnected.

  reply	other threads:[~2019-07-31 18:11 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-29 23:31 [PATCH rfc 0/2] nvme controller reset and namespace scan work race conditions Sagi Grimberg
2019-07-29 23:32 ` [PATCH rfc 1/2] nvme: don't remove namespace if revalidate failed because of controller reset Sagi Grimberg
2019-07-30  0:59   ` Keith Busch
2019-07-30  1:04     ` Sagi Grimberg
2019-07-30  1:04   ` Ming Lei
2019-07-30  1:06     ` Sagi Grimberg
2019-07-30  1:10       ` Ming Lei
2019-07-30  1:19         ` Sagi Grimberg
2019-07-30  1:30           ` Ming Lei
2019-07-30  1:40             ` Sagi Grimberg
2019-07-30  2:09               ` Ming Lei
2019-07-30 17:12                 ` Sagi Grimberg
2019-07-30 17:30                   ` Keith Busch
2019-07-30 18:15                     ` Sagi Grimberg
2019-07-31  7:13                       ` Hannes Reinecke
2019-07-31 18:08                         ` Sagi Grimberg
2019-07-31  7:01                     ` Hannes Reinecke
2019-07-31 14:16                       ` Keith Busch
2019-07-31 18:03                       ` Sagi Grimberg
2019-07-31 19:32                         ` Keith Busch
2019-07-31 20:08                           ` Sagi Grimberg
2019-07-31 20:16                             ` Keith Busch
2019-07-31 20:45                               ` Sagi Grimberg
2019-07-31 20:58                                 ` Keith Busch
2019-07-31 21:14                                   ` Sagi Grimberg
2019-07-31 21:54                                     ` Keith Busch
2019-08-01  1:13                                       ` Sagi Grimberg
2019-08-01 14:33                                         ` Keith Busch
2019-08-01 18:52                                           ` Sagi Grimberg
2019-07-31  6:58                   ` Hannes Reinecke
2019-07-31 18:11                     ` Sagi Grimberg [this message]
2019-07-31 20:02                       ` Hannes Reinecke
2019-07-31 20:16                         ` Sagi Grimberg
2019-07-31 12:18   ` Hannes Reinecke
2019-07-31 18:16     ` Sagi Grimberg
2019-07-31 20:04       ` Hannes Reinecke
2019-07-31 20:37         ` Sagi Grimberg
2019-07-29 23:32 ` [PATCH rfc 2/2] nvme: fix possible use-after-free condition when controller reset is racing namespace scanning Sagi Grimberg
2019-07-31 12:23   ` Hannes Reinecke
2019-07-31 18:21     ` Sagi Grimberg
2019-08-01  7:24       ` Hannes Reinecke
2019-08-01 18:46         ` Sagi Grimberg

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