linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Lennart Poettering <mzxreary@0pointer.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Matteo Croce <mcroce@linux.microsoft.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Jens Axboe <axboe@kernel.dk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Luca Boccassi <bluca@debian.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Damien Le Moal <damien.lemoal@wdc.com>, Tejun Heo <tj@kernel.org>,
	Javier Gonz??lez <javier@javigon.com>,
	Niklas Cassel <niklas.cassel@wdc.com>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Matthew Wilcox <willy@infradead.org>,
	JeffleXu <jefflexu@linux.alibaba.com>
Subject: Re: [PATCH v3 1/6] block: add disk sequence number
Date: Wed, 23 Jun 2021 16:12:11 +0200	[thread overview]
Message-ID: <YNNBOyUiztf2wxDu@gardel-login> (raw)
In-Reply-To: <3be63d9f-d8eb-7657-86dc-8d57187e5940@suse.de>

On Mi, 23.06.21 16:01, Hannes Reinecke (hare@suse.de) wrote:

> > Thus: a global instead of local sequence number counter is absolutely
> > *key* for the problem this is supposed to solve
> >
> Well ... except that you'll need to keep track of the numbers (otherwise you
> wouldn't know if the numbers changed, right?).
> And if you keep track of the numbers you probably will have to implement an
> uevent listener to get the events in time.

Hmm? This is backwards. The goal here is to be able to safely match up
uevents to specific uses of a block device, given that block device
names are agressively recycled.

you imply it was easy to know which device use a uevent belongs
to. But that's the problem: it is not possible to do so safely. if i
see a uevent for a block device "loop0" I cannot tell if it was from
my own use of the device or for some previous user of it.

And that's what we'd like to see fixed: i.e. we query the block device
for the seqeno now used and then we can use that to filter the uevents
and ignore the ones that do not carry the same sequence number as we
got assigned for our user.

Lennart

--
Lennart Poettering, Berlin

  parent reply	other threads:[~2021-06-23 14:12 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23 10:58 [PATCH v3 0/6] block: add a sequence number to disks Matteo Croce
2021-06-23 10:58 ` [PATCH v3 1/6] block: add disk sequence number Matteo Croce
2021-06-23 11:48   ` Christoph Hellwig
2021-06-23 13:10     ` Matteo Croce
2021-06-23 13:51       ` Lennart Poettering
2021-06-23 14:01         ` Hannes Reinecke
2021-06-23 14:07           ` Luca Boccassi
2021-06-23 14:21             ` Hannes Reinecke
2021-06-23 14:34               ` Luca Boccassi
2021-06-23 14:55               ` Lennart Poettering
2021-06-23 14:12           ` Lennart Poettering [this message]
2021-06-23 15:02             ` Hannes Reinecke
2021-06-23 15:34               ` Luca Boccassi
2021-06-23 15:48               ` Lennart Poettering
2021-06-23 14:28       ` Christoph Hellwig
2021-06-23 10:58 ` [PATCH v3 2/6] block: add ioctl to read the " Matteo Croce
2021-06-23 10:58 ` [PATCH v3 3/6] block: refactor sysfs code Matteo Croce
2021-06-23 11:52   ` Christoph Hellwig
2021-06-23 19:03     ` Matteo Croce
2021-06-24  6:12       ` Christoph Hellwig
2021-06-23 10:58 ` [PATCH v3 4/6] block: export diskseq in sysfs Matteo Croce
2021-06-23 10:58 ` [PATCH v3 5/6] block: increment sequence number Matteo Croce
2021-06-23 10:58 ` [PATCH v3 6/6] loop: " Matteo Croce
2021-06-23 11:57   ` Christoph Hellwig
2021-06-23 13:13     ` Luca Boccassi
2021-06-23 14:25       ` Christoph Hellwig
2021-06-23 15:29         ` Lennart Poettering
2021-06-24  6:11           ` Christoph Hellwig
2021-06-23 12:03 ` [PATCH v3 0/6] block: add a sequence number to disks Hannes Reinecke
2021-06-23 12:46   ` Luca Boccassi
2021-06-23 14:07   ` Lennart Poettering

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YNNBOyUiztf2wxDu@gardel-login \
    --to=mzxreary@0pointer.de \
    --cc=axboe@kernel.dk \
    --cc=bluca@debian.org \
    --cc=damien.lemoal@wdc.com \
    --cc=hare@suse.de \
    --cc=hch@infradead.org \
    --cc=javier@javigon.com \
    --cc=jefflexu@linux.alibaba.com \
    --cc=johannes.thumshirn@wdc.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mcroce@linux.microsoft.com \
    --cc=niklas.cassel@wdc.com \
    --cc=tj@kernel.org \
    --cc=viro@zeniv.linux.org.uk \
    --cc=willy@infradead.org \
    --subject='Re: [PATCH v3 1/6] block: add disk sequence number' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).