backup: Extract dirty bitmap handling as a separate function

This will be reused by the coming new transactional completion code.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1446765200-3054-5-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/backup.c

diff --git a/block/backup.c b/block/backup.c
index ec01db8..f7fcb99 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -221,6 +221,22 @@
     }
 }
 
+static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
+{
+    BdrvDirtyBitmap *bm;
+    BlockDriverState *bs = job->common.bs;
+
+    if (ret < 0 || block_job_is_cancelled(&job->common)) {
+        /* Merge the successor back into the parent, delete nothing. */
+        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);
+    }
+}
+
 static const BlockJobDriver backup_job_driver = {
     .instance_size  = sizeof(BackupBlockJob),
     .job_type       = BLOCK_JOB_TYPE_BACKUP,
@@ -443,16 +459,7 @@
     qemu_co_rwlock_unlock(&job->flush_rwlock);
 
     if (job->sync_bitmap) {
-        BdrvDirtyBitmap *bm;
-        if (ret < 0 || block_job_is_cancelled(&job->common)) {
-            /* Merge the successor back into the parent, delete nothing. */
-            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);
-        }
+        backup_cleanup_sync_bitmap(job, ret);
     }
     hbitmap_free(job->bitmap);