This patch actually implements the transactional callback system
for the drive_backup action.
(1) We manually pick up a reference to the bitmap if present to allow
its cleanup to be delayed until after all drive_backup jobs launched
by the transaction have fully completed.
(2) We create a functional closure that envelops the original drive_backup
callback, to be able to intercept the completion status and return code
for the job.
(3) We add the drive_backup_cb method for the drive_backup action, which
unpacks the completion information and invokes the final cleanup.
(4) backup_transaction_complete will perform the final cleanup on the
backup job.
(5) In the case of transaction cancellation, drive_backup_cb is still
responsible for cleaning up the mess we may have already made.
Signed-off-by: John Snow js...@redhat.com
Reviewed-by: Max Reitz mre...@redhat.com
---
block/backup.c| 9
blockdev.c| 53 ---
include/block/block_int.h | 8 +++
3 files changed, 67 insertions(+), 3 deletions(-)
diff --git a/block/backup.c b/block/backup.c
index 4ac0be8..1634c88 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -233,6 +233,15 @@ typedef struct {
int ret;
} BackupCompleteData;
+void backup_transaction_complete(BlockJob *job, int ret)
+{
+BackupBlockJob *s = container_of(job, BackupBlockJob, common);
+
+if (s-sync_bitmap) {
+bdrv_frozen_bitmap_decref(job-bs, s-sync_bitmap, ret);
+}
+}
+
static void backup_complete(BlockJob *job, void *opaque)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common);
diff --git a/blockdev.c b/blockdev.c
index f391e18..c438949 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1426,7 +1426,6 @@ static void transaction_action_callback(void *opaque, int
ret)
*
* @return The callback to be used instead of @callback.
*/
-__attribute__((__unused__))
static CallbackFn *new_action_cb_wrapper(BlkActionState *common,
void *opaque,
CallbackFn *callback,
@@ -1454,7 +1453,6 @@ static CallbackFn *new_action_cb_wrapper(BlkActionState
*common,
/**
* Undo any actions performed by the above call.
*/
-__attribute__((__unused__))
static void cancel_action_cb_wrapper(BlkActionState *common)
{
/* Stage 0: Wrapper was never created: */
@@ -1806,6 +1804,7 @@ static void do_drive_backup(const char *device, const
char *target,
BlockdevOnError on_target_error,
BlockCompletionFunc *cb, void *opaque,
Error **errp);
+static void block_job_cb(void *opaque, int ret);
static void drive_backup_prepare(BlkActionState *common, Error **errp)
{
@@ -1814,6 +1813,9 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
BlockBackend *blk;
DriveBackup *backup;
Error *local_err = NULL;
+CallbackFn *cb;
+void *opaque;
+BdrvDirtyBitmap *bmap = NULL;
assert(common-action-kind == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
backup = common-action-drive_backup;
@@ -1825,6 +1827,19 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
}
bs = blk_bs(blk);
+/* BackupBlockJob is opaque to us, so look up the bitmap ourselves */
+if (backup-has_bitmap) {
+bmap = bdrv_find_dirty_bitmap(bs, backup-bitmap);
+if (!bmap) {
+error_setg(errp, Bitmap '%s' could not be found, backup-bitmap);
+return;
+}
+}
+
+/* Create our transactional callback wrapper,
+ and register that we'd like to call .cb() later. */
+cb = new_action_cb_wrapper(common, bs, block_job_cb, opaque);
+
/* AioContext is released in .clean() */
state-aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(state-aio_context);
@@ -1837,7 +1852,7 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
backup-has_bitmap, backup-bitmap,
backup-has_on_source_error, backup-on_source_error,
backup-has_on_target_error, backup-on_target_error,
-NULL, NULL,
+cb, opaque,
local_err);
if (local_err) {
error_propagate(errp, local_err);
@@ -1846,6 +1861,12 @@ static void drive_backup_prepare(BlkActionState *common,
Error **errp)
state-bs = bs;
state-job = state-bs-job;
+/* Keep the job alive until .cb(), too:
+ * References are only incremented after the job launches successfully. */
+block_job_incref(state-job);
+if (bmap) {
+bdrv_dirty_bitmap_incref(bmap);
+}
}
static void drive_backup_abort(BlkActionState *common)
@@ -1857,6 +1878,10 @@ static void drive_backup_abort(BlkActionState *common)
if (bs bs-job bs-job == state-job) {
