@@ -268,18 +268,29 @@ static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
{
BdrvDirtyBitmap *bm;
BlockDriverState *bs = blk_bs(job->common.blk);
+ bool sync = (((ret == 0) || (job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS)) \
+ && (job->bitmap_mode != BITMAP_SYNC_MODE_NEVER));
- if (ret < 0 || job->bitmap_mode == BITMAP_SYNC_MODE_NEVER) {
+ if (sync) {
/*
- * Failure, or we don't want to synchronize the bitmap.
- * Merge the successor back into the parent, delete nothing.
+ * We succeeded, or we always intended to sync the bitmap.
+ * Delete this bitmap and install the child.
*/
- bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL);
- assert(bm);
- } else {
- /* Everything is fine, delete this bitmap and install the backup. */
bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL);
- assert(bm);
+ } else {
+ /*
+ * We failed, or we never intended to sync the bitmap anyway.
+ * Merge the successor back into the parent, keeping all data.
+ */
+ bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL);
+ }
+
+ assert(bm);
+
+ if (ret < 0 && job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS) {
+ /* If we failed and synced, merge in the bits we didn't copy: */
+ bdrv_dirty_bitmap_merge_internal(bm, job->copy_bitmap,
+ NULL, true);
}
}
@@ -1149,10 +1149,13 @@
# @never: The bitmap is never synchronized with the operation, and is
# treated solely as a read-only manifest of blocks to copy.
#
+# @always: The bitmap is always synchronized with the operation,
+# regardless of whether or not the operation was successful.
+#
# Since: 4.2
##
{ 'enum': 'BitmapSyncMode',
- 'data': ['on-success', 'never'] }
+ 'data': ['on-success', 'never', 'always'] }
##
# @MirrorCopyMode:
This adds an "always" policy for bitmap synchronization. Regardless of if the job succeeds or fails, the bitmap is *always* synchronized. This means that for backups that fail part-way through, the bitmap retains a record of which sectors need to be copied out to accomplish a new backup using the old, partial result. In effect, this allows us to "resume" a failed backup; however the new backup will be from the new point in time, so it isn't a "resume" as much as it is an "incremental retry." This can be useful in the case of extremely large backups that fail considerably through the operation and we'd like to not waste the work that was already performed. Signed-off-by: John Snow <jsnow@redhat.com> --- block/backup.c | 27 +++++++++++++++++++-------- qapi/block-core.json | 5 ++++- 2 files changed, 23 insertions(+), 9 deletions(-)