From: Christoph Hellwig <hch@infradead.org>
To: Fam Zheng <famz@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH] virtio-blk: Generate uevent after attribute available
Date: Tue, 28 Jun 2016 04:45:53 -0700 [thread overview]
Message-ID: <20160628114553.GA18354@infradead.org> (raw)
In-Reply-To: <20160628023915.6012-1-famz@redhat.com>
On Tue, Jun 28, 2016 at 10:39:15AM +0800, Fam Zheng wrote:
> Userspace listens to the KOBJ_ADD uevent generated in add_disk. At that
> point we haven't created the serial attribute file, therefore depending
> on how fast udev reacts, the /dev/disk/by-id/ entry doesn't always get
> created.
>
> This race condition can be easily reproduced by hot plugging a number of
> virtio-blk disks.
>
> Also in systemd, there used to be a related workaround in udev rules
> called 'WAIT_FOR="serial"', but it is removed in later versions.
>
> Now let's generate a KOBJ_CHANGE event after the attributes are ready.
The same race is present in other drivers as well, e.g. nvme. Please
find a way to make this work properly without needing to hack every
driver to send events manually.
next prev parent reply other threads:[~2016-06-28 11:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 2:39 [PATCH] virtio-blk: Generate uevent after attribute available Fam Zheng
2016-06-28 11:45 ` Christoph Hellwig [this message]
2016-06-29 1:24 ` Fam Zheng
2016-09-02 22:56 ` Michael S. Tsirkin
2016-09-03 7:08 ` Fam Zheng
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=20160628114553.GA18354@infradead.org \
--to=hch@infradead.org \
--cc=famz@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=virtualization@lists.linux-foundation.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).