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author | Jeff Cody <jcody@redhat.com> | 2015-10-01 00:06:37 -0400 |
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committer | Jeff Cody <jcody@redhat.com> | 2015-10-01 15:02:21 -0400 |
commit | 5279efebcf8f8fbf2ed2feed63cdb9d375c7cd07 (patch) | |
tree | d2118bda8416c830f444fc21ca671c73e2c2a11e | |
parent | fa500928ad9da6dd570918e3dfca13c029af07a8 (diff) | |
download | hqemu-5279efebcf8f8fbf2ed2feed63cdb9d375c7cd07.zip hqemu-5279efebcf8f8fbf2ed2feed63cdb9d375c7cd07.tar.gz |
block: mirror - fix full sync mode when target does not support zero init
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.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 91ed4bc5bda7e2b09eb508b07c83f4071fe0b3c9.1443705220.git.jcody@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
-rw-r--r-- | block/mirror.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/block/mirror.c b/block/mirror.c index a258926..87928ab 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; |