From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49235) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zharr-0008EE-JS for qemu-devel@nongnu.org; Thu, 01 Oct 2015 06:13:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zharq-00019H-G3 for qemu-devel@nongnu.org; Thu, 01 Oct 2015 06:13:39 -0400 Sender: Paolo Bonzini References: <0c2c486b3692736e0b7084f1bc2461ab362ac98b.1443673739.git.jcody@redhat.com> From: Paolo Bonzini Message-ID: <560D0749.9080706@redhat.com> Date: Thu, 1 Oct 2015 12:13:29 +0200 MIME-Version: 1.0 In-Reply-To: <0c2c486b3692736e0b7084f1bc2461ab362ac98b.1443673739.git.jcody@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v2] 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: Jeff Cody , qemu-devel@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-block@nongnu.org, mreitz@redhat.com On 01/10/2015 06:31, 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 | 15 ++++++++++----- > 1 file changed, 10 insertions(+), 5 deletions(-) > > diff --git a/block/mirror.c b/block/mirror.c > index a258926..5d7828b 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -61,6 +61,7 @@ typedef struct MirrorBlockJob { > int ret; > bool unmap; > bool waiting_for_io; > + bool mark_all_dirty; > } MirrorBlockJob; > > typedef struct MirrorOp { > @@ -477,7 +478,7 @@ static void coroutine_fn mirror_run(void *opaque) > } > > assert(n > 0); > - if (ret == 1) { > + if (ret == 1 || s->mark_all_dirty) { We can get the information directly in mirror_run, since we have target and we have the sync mode (it is 'full' if s->base == NULL). This avoids adding a zillionth argument to mirror_start_job. :) Paolo > bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); > } > sector_num += n; > @@ -688,7 +689,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, > int64_t buf_size, > BlockdevOnError on_source_error, > BlockdevOnError on_target_error, > - bool unmap, > + bool unmap, bool mark_all_dirty, > BlockCompletionFunc *cb, > void *opaque, Error **errp, > const BlockJobDriver *driver, > @@ -732,6 +733,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, > s->granularity = granularity; > s->buf_size = ROUND_UP(buf_size, granularity); > s->unmap = unmap; > + s->mark_all_dirty = mark_all_dirty; > > s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); > if (!s->dirty_bitmap) { > @@ -757,6 +759,7 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target, > void *opaque, Error **errp) > { > bool is_none_mode; > + bool mark_all_dirty; > BlockDriverState *base; > > if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { > @@ -764,11 +767,13 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target, > return; > } > is_none_mode = mode == MIRROR_SYNC_MODE_NONE; > + mark_all_dirty = mode == MIRROR_SYNC_MODE_FULL && > + !bdrv_has_zero_init(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, mark_all_dirty, > + cb, opaque, errp, &mirror_job_driver, is_none_mode, base); > } > > void commit_active_start(BlockDriverState *bs, BlockDriverState *base, > @@ -815,7 +820,7 @@ void commit_active_start(BlockDriverState *bs, BlockDriverState *base, > > bdrv_ref(base); > mirror_start_job(bs, base, NULL, speed, 0, 0, > - on_error, on_error, false, cb, opaque, &local_err, > + on_error, on_error, false, false, cb, opaque, &local_err, > &commit_active_job_driver, false, base); > if (local_err) { > error_propagate(errp, local_err); >