From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1H4Jio-0000ed-I1 for qemu-devel@nongnu.org; Tue, 09 Jan 2007 11:21:10 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1H4Jin-0000eA-Nx for qemu-devel@nongnu.org; Tue, 09 Jan 2007 11:21:09 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1H4Jin-0000e7-Ex for qemu-devel@nongnu.org; Tue, 09 Jan 2007 11:21:09 -0500 Received: from [128.83.139.10] (helo=mail.cs.utexas.edu) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA:32) (Exim 4.52) id 1H4Jim-00053v-WD for qemu-devel@nongnu.org; Tue, 09 Jan 2007 11:21:09 -0500 Received: from [192.168.1.104] (cpe-70-112-17-156.austin.res.rr.com [70.112.17.156]) (authenticated bits=0) by mail.cs.utexas.edu (8.13.8/8.13.8) with ESMTP id l09GL5Ss015393 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 9 Jan 2007 10:21:07 -0600 (CST) Message-ID: <45A3C0EA.7030607@cs.utexas.edu> Date: Tue, 09 Jan 2007 10:20:58 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] Create the VMDK snapshot from the QEMUmonitor. References: <64F9B87B6B770947A9F8391472E0321609E93740@ehost011-8.exch011.intermedia.net> In-Reply-To: <64F9B87B6B770947A9F8391472E0321609E93740@ehost011-8.exch011.intermedia.net> Content-Type: text/plain; charset=UTF-8; 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 Igor Lvovsky wrote: > Hi Anthony, > > I wrote the patch before Fabrice introduced his solution and I didn't look at it before I sent my patch (my mistake). > But you are right; the new snapshot infrastructure can be useful. > I'll modify my code for new approach and I hope Fabrice will accept it. > Excellent. > As for CID, I think that snapshot tag it's something else. > The CID in VMDK is value updated on the first write every time the virtual disk is opened. > I see. > By the way, I have a question: > I want to use the standard pread()/pwrite() functions instead of > pair: > lseek() > read() / write() > Why do you want to use p{read,write}()? If you are concerned about performance, you can simply cache the current file offset and only call lseek() conditionally. > I know that this may do some problem for Windows implementation, > but I can use some kind of define for Windows case. > A question is if it's acceptable. > Normally, guards for Windows specific stuff is okay but if there isn't a compelling reason to write non-portable code than I'd at least always be in favor of writing the portable version :-) Regards, Anthony Liguori > Regards, > Igor Lvovsky > > > > > -----Original Message----- > From: qemu-devel-bounces+igor.lvovsky=qumranet.com@nongnu.org [mailto:qemu-devel-bounces+igor.lvovsky=qumranet.com@nongnu.org] On Behalf Of Anthony Liguori > Sent: Tuesday, December 26, 2006 7:25 PM > To: qemu-devel@nongnu.org > Subject: Re: [Qemu-devel] [PATCH] Create the VMDK snapshot from the QEMUmonitor. > > Hi Igor, > > Out of curiousity, why didn't you use the new snapshot infrastructure > that Fabrice introduced in CVS? Shouldn't the CID just map directly to > a snapshot tag? > > Regards, > > Anthony Liguori > > Igor Lvovsky wrote: > >> Hi, >> >> This patch completes the previous one and allows the snapshot (VMDK >> style) creation from the QEMU monitor (Ctrl+Alt+2). >> >> >> >> To clarify, the previous patch implements the snapshot capabilities >> according to the "Virtual Disk Format 1.0" document. >> >> http://lists.gnu.org/archive/html/qemu-devel/2006-12/msg00311.html >> >> >> >> Implemented features: >> >> 1. Create snapshot. >> 2. CID concept to prevent snapshots chain inconsistency. >> 3. Snapshots read/write capabilities. >> >> >> >> The whole chain (base image and snapshots) created by QEMU can be >> loaded from the VMware workstation and vice versa. >> >> >> >> Igor Lvovsky. >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Qemu-devel mailing list >> Qemu-devel@nongnu.org >> http://lists.nongnu.org/mailman/listinfo/qemu-devel >> >> > > > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel > > ------------------------------------------------------------------------ > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel >