Patchwork [v6,08/12] blockdev: allow BdrvActionOps->commit() to be NULL

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Submitter Stefan Hajnoczi
Date June 24, 2013, 3:13 p.m.
Message ID <1372086800-4720-9-git-send-email-stefanha@redhat.com>
Download mbox | patch
Permalink /patch/253866/
State New
Headers show

Comments

Stefan Hajnoczi - June 24, 2013, 3:13 p.m.
Some QMP 'transaction' types don't need to do anything on .commit().
Make .commit() optional just like .abort().

The "drive-backup" action will take advantage of this, it only needs to
cancel the block job on .abort().  Other block job actions will probably
follow the same pattern, so allow .commit() to be NULL.

Suggested-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 blockdev.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/blockdev.c b/blockdev.c
index a39cea4..8dc6f2e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -789,7 +789,7 @@  typedef struct BdrvActionOps {
     size_t instance_size;
     /* Prepare the work, must NOT be NULL. */
     void (*prepare)(BlkTransactionState *common, Error **errp);
-    /* Commit the changes, must NOT be NULL. */
+    /* Commit the changes, can be NULL. */
     void (*commit)(BlkTransactionState *common);
     /* Abort the changes on fail, can be NULL. */
     void (*abort)(BlkTransactionState *common);
@@ -969,7 +969,9 @@  void qmp_transaction(TransactionActionList *dev_list, Error **errp)
     }
 
     QSIMPLEQ_FOREACH(state, &snap_bdrv_states, entry) {
-        state->ops->commit(state);
+        if (state->ops->commit) {
+            state->ops->commit(state);
+        }
     }
 
     /* success */