bdrv_has_zero_init() only has meaning for newly created images or image areas. If the mirror job itself did not create the image, it cannot rely on bdrv_has_zero_init()'s result to carry any meaning.
This is the case for drive-mirror with mode=existing and always for blockdev-mirror. Note that we only have to zero-initialize the target with sync=full, because other modes actually do not promise that the target will contain the same data as the source after the job -- sync=top only promises to copy anything allocated in the top layer, and sync=none will only copy new I/O. (Which is how mirror has always handled it.) Signed-off-by: Max Reitz <mre...@redhat.com> --- include/block/block_int.h | 2 ++ block/mirror.c | 11 ++++++++--- blockdev.c | 16 +++++++++++++--- tests/test-block-iothread.c | 2 +- 4 files changed, 24 insertions(+), 7 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 3aa1e832a8..6a0b1b5008 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -1116,6 +1116,7 @@ BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs, * @buf_size: The amount of data that can be in flight at one time. * @mode: Whether to collapse all images in the chain to the target. * @backing_mode: How to establish the target's backing chain after completion. + * @zero_target: Whether the target should be explicitly zero-initialized * @on_source_error: The action to take upon error reading from the source. * @on_target_error: The action to take upon error writing to the target. * @unmap: Whether to unmap target where source sectors only contain zeroes. @@ -1135,6 +1136,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs, int creation_flags, int64_t speed, uint32_t granularity, int64_t buf_size, MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, + bool zero_target, BlockdevOnError on_source_error, BlockdevOnError on_target_error, bool unmap, const char *filter_node_name, diff --git a/block/mirror.c b/block/mirror.c index 8cb75fb409..50188ce6e9 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -51,6 +51,8 @@ typedef struct MirrorBlockJob { Error *replace_blocker; bool is_none_mode; BlockMirrorBackingMode backing_mode; + /* Whether the target image requires explicit zero-initialization */ + bool zero_target; MirrorCopyMode copy_mode; BlockdevOnError on_source_error, on_target_error; bool synced; @@ -763,7 +765,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) int ret; int64_t count; - if (base == NULL && !bdrv_has_zero_init(target_bs)) { + if (s->zero_target) { if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length); return 0; @@ -1501,6 +1503,7 @@ static BlockJob *mirror_start_job( const char *replaces, int64_t speed, uint32_t granularity, int64_t buf_size, BlockMirrorBackingMode backing_mode, + bool zero_target, BlockdevOnError on_source_error, BlockdevOnError on_target_error, bool unmap, @@ -1628,6 +1631,7 @@ static BlockJob *mirror_start_job( s->on_target_error = on_target_error; s->is_none_mode = is_none_mode; s->backing_mode = backing_mode; + s->zero_target = zero_target; s->copy_mode = copy_mode; s->base = base; s->granularity = granularity; @@ -1713,6 +1717,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs, int creation_flags, int64_t speed, uint32_t granularity, int64_t buf_size, MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, + bool zero_target, BlockdevOnError on_source_error, BlockdevOnError on_target_error, bool unmap, const char *filter_node_name, @@ -1728,7 +1733,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs, is_none_mode = mode == MIRROR_SYNC_MODE_NONE; base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; mirror_start_job(job_id, bs, creation_flags, target, replaces, - speed, granularity, buf_size, backing_mode, + speed, granularity, buf_size, backing_mode, zero_target, on_source_error, on_target_error, unmap, NULL, NULL, &mirror_job_driver, is_none_mode, base, false, filter_node_name, true, copy_mode, errp); @@ -1755,7 +1760,7 @@ BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs, ret = mirror_start_job( job_id, bs, creation_flags, base, NULL, speed, 0, 0, - MIRROR_LEAVE_BACKING_CHAIN, + MIRROR_LEAVE_BACKING_CHAIN, false, on_error, on_error, true, cb, opaque, &commit_active_job_driver, false, base, auto_complete, filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND, diff --git a/blockdev.c b/blockdev.c index 4d141e9a1f..0323f77850 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3705,6 +3705,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs, bool has_replaces, const char *replaces, enum MirrorSyncMode sync, BlockMirrorBackingMode backing_mode, + bool zero_target, bool has_speed, int64_t speed, bool has_granularity, uint32_t granularity, bool has_buf_size, int64_t buf_size, @@ -3813,7 +3814,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs, */ mirror_start(job_id, bs, target, has_replaces ? replaces : NULL, job_flags, - speed, granularity, buf_size, sync, backing_mode, + speed, granularity, buf_size, sync, backing_mode, zero_target, on_source_error, on_target_error, unmap, filter_node_name, copy_mode, errp); } @@ -3829,6 +3830,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) int flags; int64_t size; const char *format = arg->format; + bool zero_target; int ret; bs = qmp_get_root_bs(arg->device, errp); @@ -3930,6 +3932,10 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) goto out; } + zero_target = (arg->sync == MIRROR_SYNC_MODE_FULL && + (arg->mode == NEW_IMAGE_MODE_EXISTING || + !bdrv_has_zero_init(target_bs))); + ret = bdrv_try_set_aio_context(target_bs, aio_context, errp); if (ret < 0) { bdrv_unref(target_bs); @@ -3938,7 +3944,8 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) blockdev_mirror_common(arg->has_job_id ? arg->job_id : NULL, bs, target_bs, arg->has_replaces, arg->replaces, arg->sync, - backing_mode, arg->has_speed, arg->speed, + backing_mode, zero_target, + arg->has_speed, arg->speed, arg->has_granularity, arg->granularity, arg->has_buf_size, arg->buf_size, arg->has_on_source_error, arg->on_source_error, @@ -3978,6 +3985,7 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id, AioContext *aio_context; BlockMirrorBackingMode backing_mode = MIRROR_LEAVE_BACKING_CHAIN; Error *local_err = NULL; + bool zero_target; int ret; bs = qmp_get_root_bs(device, errp); @@ -3990,6 +3998,8 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id, return; } + zero_target = (sync == MIRROR_SYNC_MODE_FULL); + aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); @@ -4000,7 +4010,7 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id, blockdev_mirror_common(has_job_id ? job_id : NULL, bs, target_bs, has_replaces, replaces, sync, backing_mode, - has_speed, speed, + zero_target, has_speed, speed, has_granularity, granularity, has_buf_size, buf_size, has_on_source_error, on_source_error, diff --git a/tests/test-block-iothread.c b/tests/test-block-iothread.c index 1949d5e61a..debfb69bfb 100644 --- a/tests/test-block-iothread.c +++ b/tests/test-block-iothread.c @@ -611,7 +611,7 @@ static void test_propagate_mirror(void) /* Start a mirror job */ mirror_start("job0", src, target, NULL, JOB_DEFAULT, 0, 0, 0, - MIRROR_SYNC_MODE_NONE, MIRROR_OPEN_BACKING_CHAIN, + MIRROR_SYNC_MODE_NONE, MIRROR_OPEN_BACKING_CHAIN, false, BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT, false, "filter_node", MIRROR_COPY_MODE_BACKGROUND, &error_abort); -- 2.21.0