commit ff52bf36a3a6c63b7528fbe64e9ed9976b221e68
author Fam Zheng <famz@redhat.com> Fri Oct 23 11:08:12 2015 +0800
committer Kevin Wolf <kwolf@redhat.com> Fri Oct 23 18:18:24 2015 +0200
tree 76500c72c596a588df89c794a6b3e4d531ace3a9
parent 1fdd4b7be3655d39c3594bc215eb1df5ce225c7d

block: Add "drained begin/end" for transactional blockdev-backup

Similar to the previous patch, make sure that external events are not
dispatched during transaction operations.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev.c

diff --git a/blockdev.c b/blockdev.c
index 0a7848b..52f44b2 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1756,6 +1756,11 @@
         return;
     }
 
+    if (!blk_is_available(blk)) {
+        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);
+        return;
+    }
+
     target = blk_by_name(backup->target);
     if (!target) {
         error_setg(errp, "Device '%s' not found", backup->target);
@@ -1770,6 +1775,8 @@
         return;
     }
     aio_context_acquire(state->aio_context);
+    state->bs = blk_bs(blk);
+    bdrv_drained_begin(state->bs);
 
     qmp_blockdev_backup(backup->device, backup->target,
                         backup->sync,
@@ -1782,7 +1789,6 @@
         return;
     }
 
-    state->bs = blk_bs(blk);
     state->job = state->bs->job;
 }
 
@@ -1802,6 +1808,7 @@
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
 
     if (state->aio_context) {
+        bdrv_drained_end(state->bs);
         aio_context_release(state->aio_context);
     }
 }