diff mbox series

[v3,06/18] block/backup: add 'never' policy to bitmap sync mode

Message ID 20190705201631.26266-7-jsnow@redhat.com
State New
Headers show
Series bitmaps: introduce 'bitmap' sync mode | expand

Commit Message

John Snow July 5, 2019, 8:16 p.m. UTC 
This adds a "never" policy for bitmap synchronization. Regardless of if
the job succeeds or fails, we never update the bitmap. This can be used
to perform differential backups, or simply to avoid the job modifying a
bitmap.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 block/backup.c       | 7 +++++--
 qapi/block-core.json | 5 ++++-
 2 files changed, 9 insertions(+), 3 deletions(-)

Comments

Max Reitz July 9, 2019, 6:38 p.m. UTC | #1 
On 05.07.19 22:16, John Snow wrote:
> This adds a "never" policy for bitmap synchronization. Regardless of if
> the job succeeds or fails, we never update the bitmap. This can be used
> to perform differential backups, or simply to avoid the job modifying a
> bitmap.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  block/backup.c       | 7 +++++--
>  qapi/block-core.json | 5 ++++-
>  2 files changed, 9 insertions(+), 3 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>
diff mbox series

Patch

diff --git a/block/backup.c b/block/backup.c
index 996941fa61..efd0dcd2e7 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -265,8 +265,11 @@  static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
     BdrvDirtyBitmap *bm;
     BlockDriverState *bs = blk_bs(job->common.blk);
 
-    if (ret < 0) {
-        /* Merge the successor back into the parent, delete nothing. */
+    if (ret < 0 || job->bitmap_mode == BITMAP_SYNC_MODE_NEVER) {
+        /*
+         * Failure, or we don't want to synchronize the bitmap.
+         * Merge the successor back into the parent, delete nothing.
+         */
         bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL);
         assert(bm);
     } else {
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 99dcd5f099..b1aaaaa98e 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1146,10 +1146,13 @@ 
 # @on-success: The bitmap is only synced when the operation is successful.
 #              This is the behavior always used for 'INCREMENTAL' backups.
 #
+# @never: The bitmap is never synchronized with the operation, and is
+#         treated solely as a read-only manifest of blocks to copy.
+#
 # Since: 4.2
 ##
 { 'enum': 'BitmapSyncMode',
-  'data': ['on-success'] }
+  'data': ['on-success', 'never'] }
 
 ##
 # @MirrorCopyMode: