From: Christoph Hellwig <hch@infradead.org>
To: Eric Blake <eblake@redhat.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Alex Bligh <alex@alex.org.uk>,
"nbd-general@lists.sourceforge.net"
<nbd-general@lists.sourceforge.net>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Josef Bacik <jbacik@fb.com>,
Jens Axboe <axboe@fb.com>, Kernel Team <Kernel-team@fb.com>,
Alex Gartrell <agartrell@fb.com>
Subject: Re: [Nbd] [PATCH 4/4] nbd: add a nbd-control interface
Date: Thu, 26 Jan 2017 00:40:47 -0800 [thread overview]
Message-ID: <20170126084047.GA9242@infradead.org> (raw)
In-Reply-To: <68e14c2e-e96e-ff8d-bd8a-0754fb970e77@redhat.com>
On Wed, Jan 25, 2017 at 03:36:20PM -0600, Eric Blake wrote:
> How do you get an fd to existing nbd block device? Your intent is to
> use an ioctl to request creating/opening a new nbd device that no one
> else is using; opening an existing device in order to send that ioctl
> may have negative ramifications to the actual user of that existing
> device, if not permissions issues that prevent the open from even
> happening. Having a separate control fd makes it obvious that you are
> asking for a new nbd device, and don't want to stomp on any existing
> devices.
Yes, - this whole concept of needing a device first to then associate
it with a backing store is something we had a in a lot of drivers,
and it's always been a major problem. Thus we've been slowly moving
all the drivers off it.
next prev parent reply other threads:[~2017-01-26 8:40 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-20 21:56 [PATCH 1/4] nbd: use our own workqueue for recv threads Josef Bacik
2017-01-20 21:56 ` [PATCH 2/4] miscdevice: add a minor number for nbd-control Josef Bacik
2017-01-21 9:03 ` Greg KH
2017-01-21 13:25 ` Josef Bacik
2017-01-22 11:09 ` Greg KH
2017-01-20 21:56 ` [PATCH 3/4] nbd: use an idr to keep track of nbd devices Josef Bacik
2017-01-20 21:56 ` [PATCH 4/4] nbd: add a nbd-control interface Josef Bacik
2017-01-21 9:05 ` Greg KH
2017-01-23 14:42 ` Josef Bacik
2017-01-23 14:52 ` Greg KH
2017-01-23 14:57 ` Josef Bacik
2017-01-23 15:03 ` Greg KH
2017-01-23 15:52 ` Josef Bacik
2017-01-24 7:11 ` Greg KH
2017-01-25 8:55 ` [Nbd] " Wouter Verhelst
2017-01-25 13:47 ` Josef Bacik
2017-01-25 14:23 ` Arnd Bergmann
2017-01-25 16:48 ` Alex Gartrell
2017-01-25 18:21 ` [Nbd] " Wouter Verhelst
2017-01-25 18:25 ` Alex Bligh
2017-01-25 21:30 ` Greg KH
2017-01-25 21:36 ` Eric Blake
2017-01-26 8:40 ` Christoph Hellwig [this message]
2017-01-26 9:17 ` Greg KH
2017-01-26 13:17 ` Christoph Hellwig
2017-01-25 18:24 ` Paul Clements
2017-01-21 12:11 ` Wouter Verhelst
2017-01-21 13:44 ` Josef Bacik
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