From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KYNti-0004oM-NI for qemu-devel@nongnu.org; Wed, 27 Aug 2008 12:29:30 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KYNtg-0004nL-TJ for qemu-devel@nongnu.org; Wed, 27 Aug 2008 12:29:30 -0400 Received: from [199.232.76.173] (port=39785 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KYNtg-0004n8-FK for qemu-devel@nongnu.org; Wed, 27 Aug 2008 12:29:28 -0400 Received: from ag-out-0708.google.com ([72.14.246.247]:11754) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1KYNtf-00053x-BG for qemu-devel@nongnu.org; Wed, 27 Aug 2008 12:29:28 -0400 Received: by ag-out-0708.google.com with SMTP id 31so7006673agc.5 for ; Wed, 27 Aug 2008 09:29:26 -0700 (PDT) Message-ID: <48B580B5.8030804@codemonkey.ws> Date: Wed, 27 Aug 2008 11:28:37 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel][PATCH] qemu-fuse References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Shahar Frank wrote: > Hi All, > > The attached is a small utility to mount qemu images as pseudo > partition files. It can be very useful to access (rw) images from the > host. > I would not use it for production, but it seems to be stable. > Heh, quite similar to: http://hg.codemonkey.ws/qemu-img-mount/file/9f11265882b3/qemu-img-mount.diff So this was my first approach to solving this problem that I ended up abandoning in favor of qemu-nbd (which is now in the tree). The main limitation I found with fuse is that by default (and it takes a lot to change this), fuse filesystems are unreadable by root. This means that you cannot easily mount -oloop something in a fuse filesystem. What I really wanted, was the ability to say something like: qemu-img mount -p1 foo.img /mnt and it would Just Work. The only two options I found that could make this work is: 1) disable the root readable limitation in fuse, this has to be done globally and I suspect is unlikely to be done by distros. 2) add support to qemu-img-mount to use filesystems libraries like libe2fs to read and present the filesystem contents. This has the advantage of working entirely as the user who issues the command but has the disadvantage of requiring a lot of effort without being able to support all filesystems that Linux supports. So that's why I settled on qemu-nbd. Regards, Anthony Liguori