From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36624) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VHFM0-0001kG-SB for qemu-devel@nongnu.org; Wed, 04 Sep 2013 11:50:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VHFLs-0000Xd-DG for qemu-devel@nongnu.org; Wed, 04 Sep 2013 11:50:48 -0400 Received: from mail-ee0-x22e.google.com ([2a00:1450:4013:c00::22e]:58138) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VHFLs-0000XV-0y for qemu-devel@nongnu.org; Wed, 04 Sep 2013 11:50:40 -0400 Received: by mail-ee0-f46.google.com with SMTP id c13so278927eek.19 for ; Wed, 04 Sep 2013 08:50:39 -0700 (PDT) Date: Wed, 4 Sep 2013 17:50:36 +0200 From: Stefan Hajnoczi Message-ID: <20130904155036.GF12733@stefanha-thinkpad.redhat.com> References: <1377784821-29561-1-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1377784821-29561-1-git-send-email-pbonzini@redhat.com> Subject: Re: [Qemu-devel] [PATCH v4 00/21] Add qemu-img subcommand to dump file metadata List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com On Thu, Aug 29, 2013 at 04:00:00PM +0200, Paolo Bonzini wrote: > This series adds a subcommand to "qemu-img" that can dump file metadata. > Metadata that is dumped includes: > > - whether blocks are allocated in bs->file and, if so, where > > - whether blocks are zero > > - whether data is read from bs or bs->backing_hd > > Metadata is dumped for an entire chain of images. One example usage is > (for non-compressed, non-encrypted images) to transform the metadata > into a Linux device-mapper setup, and make a qcow2 image available (for > read only) as a block device. Another possible usage is to determine > the used areas of a file, and convert it in place to another format. > Alternatively, the richer data can be used by block jobs to quickly > determine if a block is zero without reading it. > > The patches implement a new operation, bdrv_co_get_block_status, that > supersedes bdrv_co_is_allocated. The bdrv_is_allocated API is still > available of course, and implemented on top of the new operation. > > Patches 1-3 touch cow, which uses bdrv_co_is_allocated during its reads > and writes. I optimized it a bit because it was unbearably slow during > testing. With these patches (also tested with blkverify), booting of > a cow guest image is not particularly slow. > > Patch 4 fixes the bs->total_sectors file size cache, which is used in > bdrv_co_get_block_status to clamp invalid input. > > Patches 5 to 8 clean up the bdrv_is_allocated and bdrv_is_allocated_above > implementation, eliminating some code duplication. > > Patches 9 and 10 tweak bdrv_has_zero_init and its usage in qemu-img in > a way that helps when implementing the new API. > > Patches 11 to 15 implement bdrv_get_block_status and change the formats > to report all the available information. > > Patch 16 and 17 adds the "map" subcommand to qemu-img, and the relevant > documentation. > > Finally, patches 18 to 21 tweak the implementation to extract more > information from protocols, and combine this information with format > metadata whenever possible. Please rebase on qemu.git/master (includes raw BSD and other potential conflicts). Stefan