From: Christoph Hellwig <hch@infradead.org>
To: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>,
Christoph Hellwig <hch@infradead.org>,
Ming Lei <ming.lei@redhat.com>,
John Meneghini <jmeneghi@redhat.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: nvme/pcie hot plug results in /dev name change
Date: Tue, 14 Feb 2023 22:18:16 -0800 [thread overview]
Message-ID: <Y+x5KLpMrurxcnc5@infradead.org> (raw)
In-Reply-To: <Y+pmI52Ahfn/hF6m@kbusch-mbp>
On Mon, Feb 13, 2023 at 09:32:35AM -0700, Keith Busch wrote:
> > Isn't this equivalent to dm-mpath queue_if_no_path or no_path_timeout ?
>
> Similiar, but generic to non-multipath devices.
Exactly!
> > We can keep the mpath device around, but if not, what is the desired
> > behavior from the upper layers?
>
> I don't think we're looking for any behavioral changes in the upper layers.
There's really two different things, which would both a problem:
- make the device not go away if we expect it to come back by using
the multipath code
- tell the upper layer that a devie went away when it actually did
Right now if user has a block device open, it will keep a reference to
it forever. If we send a notification to the upper layer not only can
it release that refrence, but it also knows the device went away.
This really helps to e.g. rebalance data in a RAID or RAID-like setup.
next prev parent reply other threads:[~2023-02-15 6:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 19:50 nvme/pcie hot plug results in /dev name change John Meneghini
2023-01-20 21:42 ` Keith Busch
2023-01-21 7:01 ` Christoph Hellwig
2023-01-29 10:28 ` Ming Lei
2023-01-31 16:38 ` Keith Busch
2023-02-01 2:33 ` Ming Lei
2023-02-01 6:27 ` Christoph Hellwig
2023-02-01 16:31 ` Keith Busch
2023-02-13 14:01 ` Sagi Grimberg
2023-02-13 16:32 ` Keith Busch
2023-02-14 0:04 ` Ming Lei
2023-02-14 9:18 ` Sagi Grimberg
2023-02-15 1:04 ` Ming Lei
2023-02-14 16:17 ` Keith Busch
2023-02-15 1:11 ` Ming Lei
2023-02-14 9:04 ` Sagi Grimberg
2023-02-15 6:18 ` Christoph Hellwig [this message]
2023-02-15 8:56 ` Sagi Grimberg
2023-02-15 22:18 ` Keith Busch
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