We should not copy non-dirty clusters in write notifiers. So, initialize copy_bitmap from sync_bitmap.
Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]> --- block/backup.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/block/backup.c b/block/backup.c index 08efec639f..07f4ae846b 100644 --- a/block/backup.c +++ b/block/backup.c @@ -422,6 +422,43 @@ out: return ret; } +/* init copy_bitmap from sync_bitmap */ +static void backup_incremental_init_copy_bitmap(BackupBlockJob *job) +{ + BdrvDirtyBitmapIter *dbi; + int64_t offset; + int64_t end = DIV_ROUND_UP(bdrv_dirty_bitmap_size(job->sync_bitmap), + job->cluster_size); + + dbi = bdrv_dirty_iter_new(job->sync_bitmap); + while ((offset = bdrv_dirty_iter_next(dbi)) != -1) { + int64_t cluster = offset / job->cluster_size; + int64_t next_cluster; + + offset += bdrv_dirty_bitmap_granularity(job->sync_bitmap); + if (offset >= bdrv_dirty_bitmap_size(job->sync_bitmap)) { + hbitmap_set(job->copy_bitmap, cluster, end - cluster); + break; + } + + offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset); + if (offset == -1) { + hbitmap_set(job->copy_bitmap, cluster, end - cluster); + break; + } + + next_cluster = DIV_ROUND_UP(offset, job->cluster_size); + hbitmap_set(job->copy_bitmap, cluster, next_cluster - cluster); + if (next_cluster >= end) { + break; + } + + bdrv_set_dirty_iter(dbi, next_cluster * job->cluster_size); + } + + bdrv_dirty_iter_free(dbi); +} + static void coroutine_fn backup_run(void *opaque) { BackupBlockJob *job = opaque; @@ -435,20 +472,26 @@ static void coroutine_fn backup_run(void *opaque) nb_clusters = DIV_ROUND_UP(job->common.len, job->cluster_size); job->copy_bitmap = hbitmap_alloc(nb_clusters, 0); - hbitmap_set(job->copy_bitmap, 0, nb_clusters); job->before_write.notify = backup_before_write_notify; bdrv_add_before_write_notifier(bs, &job->before_write); if (job->sync_mode == MIRROR_SYNC_MODE_NONE) { + /* Here we set all bits in job->copy_bitmap to allow copying clusters + * which are going to be changed (none-mode semantics). It doesn't mean + * that we want to copy _all_ clusters. + */ + hbitmap_set(job->copy_bitmap, 0, nb_clusters); while (!block_job_is_cancelled(&job->common)) { /* Yield until the job is cancelled. We just let our before_write * notify callback service CoW requests. */ block_job_yield(&job->common); } } else if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) { + backup_incremental_init_copy_bitmap(job); ret = backup_run_incremental(job); } else { + hbitmap_set(job->copy_bitmap, 0, nb_clusters); /* Both FULL and TOP SYNC_MODE's require copying.. */ for (offset = 0; offset < job->common.len; offset += job->cluster_size) { -- 2.11.1
