[Qemu-block] [RFC PATCH 05/12] blockdev: Lock BDS during drive-backup transaction

[Fam Zheng]

To save the bs pointer for drive_backup_clean, pull the assignment to
state->bs up. It will not be a problem for drive_backup_abort because
state->job will still be NULL.

Signed-off-by: Fam Zheng <address@hidden>
---
 blockdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index 1c3946a..517def4 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1588,6 +1588,8 @@ static void drive_backup_prepare(BlkTransactionState 
*common, Error **errp)
     /* AioContext is released in .clean() */
     state->aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(state->aio_context);
+    bdrv_lock(bs);
+    state->bs = bs;
 
     qmp_drive_backup(backup->device, backup->target,
                      backup->has_format, backup->format,
@@ -1603,7 +1605,6 @@ static void drive_backup_prepare(BlkTransactionState 
*common, Error **errp)
         return;
     }
 
-    state->bs = bs;
     state->job = state->bs->job;
 }
 
@@ -1623,6 +1624,7 @@ static void drive_backup_clean(BlkTransactionState 
*common)
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
 
     if (state->aio_context) {
+        bdrv_unlock(state->bs);
         aio_context_release(state->aio_context);
     }
 }
-- 
2.4.2