From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1DzEVJ-0006TV-Ko for qemu-devel@nongnu.org; Sun, 31 Jul 2005 10:09:27 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1DzEVG-0006SK-Vi for qemu-devel@nongnu.org; Sun, 31 Jul 2005 10:09:23 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1DzEVG-0006RH-SY for qemu-devel@nongnu.org; Sun, 31 Jul 2005 10:09:22 -0400 Received: from [80.91.229.2] (helo=ciao.gmane.org) by monty-python.gnu.org with esmtp (TLS-1.0:RSA_AES_128_CBC_SHA:16) (Exim 4.34) id 1DzEal-00071X-KB for qemu-devel@nongnu.org; Sun, 31 Jul 2005 10:15:03 -0400 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1DzEOn-0005bN-TG for qemu-devel@nongnu.org; Sun, 31 Jul 2005 16:02:41 +0200 Received: from dsl093-191-107.nyc2.dsl.speakeasy.net ([66.93.191.107]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 31 Jul 2005 16:02:41 +0200 Received: from esj by dsl093-191-107.nyc2.dsl.speakeasy.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 31 Jul 2005 16:02:41 +0200 From: "Eric S. Johansson" Date: Sun, 31 Jul 2005 10:01:29 -0400 Message-ID: References: <200507310258.13169.mark.williamson@cl.cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit In-Reply-To: <200507310258.13169.mark.williamson@cl.cam.ac.uk> Sender: news Subject: [Qemu-devel] Re: file system sharing 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 Mark Williamson wrote: > If only one machine (host or guest) has mounted the device then it should > always be safe to do this. You may get away with read only mounting in one > and writing in the other but it's not a reliable solution. Never allow more > than one writer to the filesystem - this does bad things to your filesystem! I am well aware of these issues having worked on filesystems in the 1980s and having designed and built one of the first RPC based networked filesystems in the late 80s for a CAD/CAM company. To this day the nova architecture gives me the willies. I suspect based on a comment that someone else made about caching that I would need some sort of event to trigger a flush either by an explicit flush call or a close. Would unmounting the disk image create such an event? > > If you're using a file-based disk and it's partitioned you'll need to use > lomount http://www.dad-answers.com/qemu/utilities/QEMU-HD-Mounter/lomount/ to > mount the right partition in the host. so what I can do is create the partition image on the host, start up qemu with that multi-partition disk image, do what I need to in qemu, shut down qemu and then I have a modified disk image. if I need to modify it from the host, then I can use lomount to make it accessible as the local filesystem. Very cool. one more question on this theme. How do I know when the guest OS has finished booting? The reason I ask is I am planning on using ssh to perform various operations on the guest OS once it's up. >>ideally, I would like to "import" my flash memory device into the guest >>OS side (USB based) but if I can create a "virtual" flash disk and when >>I'm done modifying it, physically copy the file based image to the >>physical flash, I would be happy. > > > I imagine just giving the guest access to the device file would work. I'm not entirely sure how to do that. would I just do something like: -hdc /dev/sda1 as part of the command line? > > HTH, > Mark