From: David Vrabel <david.vrabel@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH 2/6] xen-blkfront: handle backend CLOSED without CLOSING
Date: Thu, 4 Oct 2012 11:31:35 +0100 [thread overview]
Message-ID: <506D6587.7010100@citrix.com> (raw)
In-Reply-To: <506D7D9A020000780009F9C8@nat28.tlf.novell.com>
On 04/10/12 11:14, Jan Beulich wrote:
>>>> On 25.09.12 at 19:53, David Vrabel <david.vrabel@citrix.com> wrote:
>> @@ -1167,7 +1168,8 @@ blkfront_closing(struct blkfront_info *info)
>>
>> mutex_lock(&bdev->bd_mutex);
>>
>> - if (bdev->bd_openers) {
>> + /* If the backend is already CLOSED, close now. */
>> + if (bdev->bd_openers && backend_state != XenbusStateClosed) {
>> xenbus_dev_error(xbdev, -EBUSY,
>> "Device in use; refusing to close");
>> xenbus_switch_state(xbdev, XenbusStateClosing);
>
> This looks wrong to me on a second glance: As long as there
> are users of the device, I don't think we want to go into Closed
> ourselves, irrespective of the backend state.
Any users of the frontend device are screwed either way, as the backend
is gone. It seems sensible to handle this case the same as (e.g.,) a
physical unplug of a USB storage device. Removing the device and
forcing all outstanding I/O to fail immediately rather than lingering in
the rings, going nowhere.
David
next prev parent reply other threads:[~2012-10-04 10:31 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 16:04 [PATCH 0/6] xen: frontend devices should handle missed backend CLOSING David Vrabel
2012-09-21 16:04 ` [PATCH 1/6] xen-netfront: handle backend CLOSED without CLOSING David Vrabel
2012-09-21 16:04 ` [PATCH 2/6] xen-blkfront: " David Vrabel
2012-09-25 17:53 ` David Vrabel
2012-10-01 17:19 ` David Vrabel
2012-10-02 20:02 ` Konrad Rzeszutek Wilk
2012-10-05 11:42 ` David Vrabel
2012-10-05 11:55 ` Jan Beulich
2012-10-05 15:57 ` David Vrabel
2012-10-09 16:30 ` Konrad Rzeszutek Wilk
2012-10-04 10:14 ` [Xen-devel] " Jan Beulich
2012-10-04 10:31 ` David Vrabel [this message]
2012-09-21 16:04 ` [PATCH 3/6] xen-pcifront: " David Vrabel
2012-09-21 16:04 ` [PATCH 4/6] xen-fbfront: " David Vrabel
2012-09-21 16:04 ` [PATCH 5/6] xen-kbdfront: " David Vrabel
2012-09-21 16:04 ` [PATCH 6/6] xen/hvc: " David Vrabel
2012-09-21 17:10 ` [PATCH 0/6] xen: frontend devices should handle missed backend CLOSING Konrad Rzeszutek Wilk
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