From: Prasanna Kalever <email@example.com>
To: Matteo Croce <firstname.lastname@example.org>
Cc: Ming Lei <email@example.com>,
Prasanna Kumar Kalever <firstname.lastname@example.org>,
email@example.com, Josef Bacik <firstname.lastname@example.org>,
Jens Axboe <email@example.com>, Ilya Dryomov <firstname.lastname@example.org>,
Xiubo Li <email@example.com>,
Lennart Poettering <firstname.lastname@example.org>,
Luca Boccassi <email@example.com>
Subject: Re: [PATCH] nbd: provide a way for userspace processes to identify device backends
Date: Thu, 27 May 2021 10:52:50 +0530 [thread overview]
Message-ID: <CANwsLLEtOws-+X=3CCGzO88poP9NF8uNN8aW9wHOJ+QA=SFH3A@mail.gmail.com> (raw)
On Wed, May 26, 2021 at 7:44 PM Matteo Croce <firstname.lastname@example.org> wrote:
> On Wed, May 19, 2021 at 4:33 PM Matteo Croce <email@example.com> wrote:
> > On Tue, May 18, 2021 at 9:52 AM Prasanna Kalever <firstname.lastname@example.org> wrote:
> > > > BTW, loop has similar issue, and patch of 'block: add a sequence number to disks'
> > > > is added for addressing this issue, what do you think of that generic
> > > > approach wrt. this nbd's issue? such as used the exposed sysfs sequence number
> > > > for addressing this issue?
> > > >
> > > > https://lore.kernel.org/linux-block/YH81n34d2G3C4Re+@gardel-login/#r
> > >
> > > If I understand the changes and the background of the fix correctly, I
> > > think with that fix author is trying to monotonically increase the seq
> > > number and add it to the disk on every single device map/attach and
> > > expose it through the sysfs, which will help the userspace processes
> > > further to correlate events for particular and specific devices that
> > > reuse the same loop device.
> > >
> > Yes, but nothing prevents to use diskseq in nbd, and increase it on reconfigure.
> > That would allow to detect if the device has been reconfigured.
> > Regards,
> > --
> > per aspera ad upstream
> FYI: I just sent a v2 of the diskseq change
Thanks, Matteo, I will take a look.
Just to set the expectation here, I don't have any thoughts on
leverage the diskseq number for nbd as part of this patch. This patch
is trying to solve a different problem which is more severe for us
than helping to identify the reconfigured events.
That all said, once diskseq patches are merged, I will surely open a
new patch with the required changes in nbd, to leverage diskseq
> per aspera ad upstream
next prev parent reply other threads:[~2021-05-27 5:23 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 10:28 [PATCH] nbd: provide a way for userspace processes to identify device backends Prasanna Kumar Kalever
2021-04-30 2:14 ` Xiubo Li
2021-05-17 14:42 ` Prasanna Kalever
2021-05-18 0:29 ` Ming Lei
2021-05-18 7:52 ` Prasanna Kalever
2021-05-18 9:24 ` Ming Lei
2021-05-18 9:49 ` Prasanna Kalever
2021-05-19 7:54 ` Ming Lei
2021-05-19 14:17 ` Prasanna Kalever
2021-05-19 14:33 ` Matteo Croce
2021-05-26 14:13 ` Matteo Croce
2021-05-27 5:22 ` Prasanna Kalever [this message]
2021-06-16 8:42 ` Prasanna Kalever
2021-06-16 12:59 ` Jens Axboe
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