[Qemu-devel] [RFC 6/9] blockdev: make BlockJobTxn available to qmp 'transaction'

[Stefan Hajnoczi <stefanha@redhat.com>]

Provide a BlockJobTxn to actions executed in a qmp 'transaction'
command.  This allows actions to make their block jobs either complete
as a group or fail/cancel together.

The next patch adds the first user.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 blockdev.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index e30e986..2cdc7f3 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1267,6 +1267,7 @@ typedef struct BlkActionOps {
 struct BlkActionState {
     TransactionAction *action;
     const BlkActionOps *ops;
+    BlockJobTxn *block_job_txn;
     QSIMPLEQ_ENTRY(BlkActionState) entry;
 };
 
@@ -1869,12 +1870,15 @@ static const BlkActionOps actions[] = {
 void qmp_transaction(TransactionActionList *dev_list, Error **errp)
 {
     TransactionActionList *dev_entry = dev_list;
+    BlockJobTxn *block_job_txn;
     BlkActionState *state, *next;
     Error *local_err = NULL;
 
     QSIMPLEQ_HEAD(snap_bdrv_states, BlkActionState) snap_bdrv_states;
     QSIMPLEQ_INIT(&snap_bdrv_states);
 
+    block_job_txn = block_job_txn_new();
+
     /* drain all i/o before any operations */
     bdrv_drain_all();
 
@@ -1894,6 +1898,7 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
         state = g_malloc0(ops->instance_size);
         state->ops = ops;
         state->action = dev_info;
+        state->block_job_txn = block_job_txn;
         QSIMPLEQ_INSERT_TAIL(&snap_bdrv_states, state, entry);
 
         state->ops->prepare(state, &local_err);
@@ -1903,6 +1908,8 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
         }
     }
 
+    block_job_txn_begin(block_job_txn);
+
     QSIMPLEQ_FOREACH(state, &snap_bdrv_states, entry) {
         if (state->ops->commit) {
             state->ops->commit(state);
@@ -1913,6 +1920,8 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
     goto exit;
 
 delete_and_fail:
+    block_job_txn_begin(block_job_txn);
+
     /* failure, and it is all-or-none; roll back all operations */
     QSIMPLEQ_FOREACH(state, &snap_bdrv_states, entry) {
         if (state->ops->abort) {
-- 
2.4.2