From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47464) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fNgGX-0004iv-HE for qemu-devel@nongnu.org; Tue, 29 May 2018 11:10:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fNgGW-0002fh-IH for qemu-devel@nongnu.org; Tue, 29 May 2018 11:10:25 -0400 Date: Tue, 29 May 2018 17:10:16 +0200 From: Kevin Wolf Message-ID: <20180529151016.GF4756@localhost.localdomain> References: <20180425183223.580566-1-eblake@redhat.com> <20180425183223.580566-3-eblake@redhat.com> <20180528105232.GD4580@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH 2/8] qcow: Switch get_cluster_offset to be byte-based List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: qemu-devel@nongnu.org, "open list:qcow" , Max Reitz Am 29.05.2018 um 17:03 hat Eric Blake geschrieben: > On 05/28/2018 05:52 AM, Kevin Wolf wrote: > > Am 25.04.2018 um 20:32 hat Eric Blake geschrieben: > > > We are gradually moving away from sector-based interfaces, towards > > > byte-based. Make the change for the internal helper function > > > get_cluster_offset(), by changing n_start and n_end to by byte > > > offsets rather than sector indices within the cluster being > > > allocated. > > > > > > A later patch will then switch the qcow driver as a whole over > > > to byte-based operation. > > > > > > Signed-off-by: Eric Blake > > > --- > > > block/qcow.c | 28 ++++++++++++++-------------- > > > 1 file changed, 14 insertions(+), 14 deletions(-) > > > > > > > + for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { > > > if (i < n_start || i >= n_end) { > > > - memset(s->cluster_data, 0x00, 512); > > > + memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); > > > if (qcrypto_block_encrypt(s->crypto, > > > - (start_sect + i) * > > > - BDRV_SECTOR_SIZE, > > > + start_offset + i, > > > s->cluster_data, > > > BDRV_SECTOR_SIZE, > > > NULL) < 0) { > > > > This code is still working in blocks of BDRV_SECTOR_SIZE here - which > > you do need to keep at least partially because that's the block size > > that qcrypto_block_encrypt() works with. qcrypto_block_qcow_encrypt() > > even asserts it. > > > > However, this means that even though n_start and n_end are byte-based > > now, the code only works correctly with encrypted images if they are > > multiples of BDRV_SECTOR_SIZE. This is currently true and we could > > assert it, but it would kind of defeat the purpose of the patch. > > But in patch 5, I intentionally kept bs->bl.request_alignment at 512, so I'd > rather just assert that n_start and n_end are properly aligned than to worry > about rounding issues. Yes, I hadn't read the whole series yet. So, sure, adding an assertion works for me. Kevin