From: Fam Zheng <famz@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
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: Wed, 29 Jun 2016 09:24:15 +0800 [thread overview]
Message-ID: <20160629012414.GA23296@ad.usersys.redhat.com> (raw)
In-Reply-To: <20160628114553.GA18354@infradead.org>
On Tue, 06/28 04:45, Christoph Hellwig wrote:
> 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.
OK, I'll take a look today!
Fam
next prev parent reply other threads:[~2016-06-29 1:24 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
2016-06-29 1:24 ` Fam Zheng [this message]
2016-09-02 22:56 ` Michael S. Tsirkin
2016-09-03 7:08 ` Fam Zheng
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