From 4c46f8b0f6fd8efba5e4d0b738b4f01ffcb92d33 Mon Sep 17 00:00:00 2001 From: John Snow Date: Tue, 9 Jul 2019 21:12:30 -0400 Subject: [PATCH qemu 35/39] drive-mirror: add support for conditional and always bitmap sync modes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Teach mirror two new tricks for using bitmaps: Always: no matter what, we synchronize the copy_bitmap back to the sync_bitmap. In effect, this allows us resume a failed mirror at a later date. Conditional: On success only, we sync the bitmap. This is akin to incremental backup modes; we can use this bitmap to later refresh a successfully created mirror. Signed-off-by: Fabian Grünbichler --- block/mirror.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index fd7f574365..40d174a625 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -645,8 +645,6 @@ static int mirror_exit_common(Job *job) bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs); } - bdrv_release_dirty_bitmap(s->dirty_bitmap); - /* Make sure that the source BDS doesn't go away during bdrv_replace_node, * before we can call bdrv_drained_end */ bdrv_ref(src); @@ -731,6 +729,18 @@ static int mirror_exit_common(Job *job) blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort); blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort); + if (s->sync_bitmap) { + if (s->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS || + (s->bitmap_mode == BITMAP_SYNC_MODE_ON_SUCCESS && + job->ret == 0 && ret == 0)) { + /* Success; synchronize copy back to sync. */ + bdrv_clear_dirty_bitmap(s->sync_bitmap, NULL); + bdrv_merge_dirty_bitmap(s->sync_bitmap, s->dirty_bitmap, + NULL, &error_abort); + } + } + bdrv_release_dirty_bitmap(s->dirty_bitmap); + bs_opaque->job = NULL; bdrv_drained_end(src); @@ -1562,10 +1572,6 @@ static BlockJob *mirror_start_job( " sync mode", MirrorSyncMode_str(sync_mode)); return NULL; - } else if (bitmap_mode != BITMAP_SYNC_MODE_NEVER) { - error_setg(errp, - "Bitmap Sync Mode '%s' is not supported by Mirror", - BitmapSyncMode_str(bitmap_mode)); } } else if (bitmap) { error_setg(errp, @@ -1582,6 +1588,12 @@ static BlockJob *mirror_start_job( return NULL; } granularity = bdrv_dirty_bitmap_granularity(bitmap); + + if (bitmap_mode != BITMAP_SYNC_MODE_NEVER) { + if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, errp)) { + return NULL; + } + } } else if (granularity == 0) { granularity = bdrv_get_default_bitmap_granularity(target); } -- 2.20.1