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 <jc...@redhat.com>
---
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) {
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);
--
1.9.3
