From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46992) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZheXP-0001LP-In for qemu-devel@nongnu.org; Thu, 01 Oct 2015 10:08:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZheXL-0007el-32 for qemu-devel@nongnu.org; Thu, 01 Oct 2015 10:08:47 -0400 Date: Thu, 1 Oct 2015 10:08:32 -0400 From: Jeff Cody Message-ID: <20151001140832.GE11943@localhost.localdomain> References: <91ed4bc5bda7e2b09eb508b07c83f4071fe0b3c9.1443705220.git.jcody@redhat.com> <560D3693.7090108@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <560D3693.7090108@redhat.com> Subject: Re: [Qemu-devel] [PATCH v3] block: mirror - fix full sync mode when target does not support zero init List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: kwolf@redhat.com, qemu-block@nongnu.org, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com On Thu, Oct 01, 2015 at 03:35:15PM +0200, Paolo Bonzini wrote: > > > On 01/10/2015 15:14, Jeff Cody wrote: > > During mirror, if the target device does not support zero init, a > > mirror may result in a corrupted image for sync="full" mode. > > > > This is due to how the initial dirty bitmap is set up prior to copying > > data - we did not mark sectors as dirty that are unallocated. This > > means those unallocated sectors are skipped over on the target, and for > > a device without zero init, invalid data may reside in those holes. > > > > If both of the following conditions are true, then we will explicitly > > mark all sectors as dirty: > > > > 1.) sync = "full" > > 2.) bdrv_has_zero_init(target) == false > > > > If the target does support zero init, but a target image is passed in > > with data already present (i.e. an "existing" image), it is assumed the > > data present in the existing image is valid data for those sectors. > > > > Signed-off-by: Jeff Cody > > --- > > block/mirror.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/block/mirror.c b/block/mirror.c > > index a258926..ce367e0 100644 > > --- a/block/mirror.c > > +++ b/block/mirror.c > > @@ -455,6 +455,8 @@ static void coroutine_fn mirror_run(void *opaque) > > if (!s->is_none_mode) { > > /* First part, loop on the sectors and initialize the dirty bitmap. */ > > BlockDriverState *base = s->base; > > + bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target); > > + > > for (sector_num = 0; sector_num < end; ) { > > /* Just to make sure we are not exceeding int limit. */ > > int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, > > @@ -477,7 +479,7 @@ static void coroutine_fn mirror_run(void *opaque) > > } > > > > assert(n > 0); > > - if (ret == 1) { > > + if (ret == 1 || mark_all_dirty) { > > bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); > > } > > sector_num += n; > > @@ -767,8 +769,8 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target, > > base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL; > > mirror_start_job(bs, target, replaces, > > speed, granularity, buf_size, > > - on_source_error, on_target_error, unmap, cb, opaque, errp, > > - &mirror_job_driver, is_none_mode, base); > > + on_source_error, on_target_error, unmap, > > + cb, opaque, errp, &mirror_job_driver, is_none_mode, base); > > } > > > > void commit_active_start(BlockDriverState *bs, BlockDriverState *base, > > > > Unnecessary last hunk, but the patch is good anyway. > > Reviewed-by: Paolo Bonzini Thanks, I'll go ahead and drop the last hunk when applying. Jeff