This patch actually implements the transactional callback system for the drive_backup transaction.
(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> --- block/backup.c | 9 ++++++++ blockdev.c | 52 ++++++++++++++++++++++++++++++++++++++++++++--- include/block/block_int.h | 8 ++++++++ 3 files changed, 66 insertions(+), 3 deletions(-) diff --git a/block/backup.c b/block/backup.c index 1fefca7..f526141 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 16b2cf7..f529ac2 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2749,7 +2749,6 @@ 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, @@ -2777,7 +2776,6 @@ 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: */ @@ -3123,6 +3121,9 @@ 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; @@ -3134,6 +3135,19 @@ 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); @@ -3146,7 +3160,7 @@ 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); @@ -3155,6 +3169,12 @@ 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) @@ -3166,6 +3186,10 @@ static void drive_backup_abort(BlkActionState *common) if (bs && bs->job && bs->job == state->job) { block_job_cancel_sync(bs->job); } + + /* Undo any callback actions we may have done. Putting down references + * obtained during prepare() is handled by cb(). */ + cancel_action_cb_wrapper(common); } static void drive_backup_clean(BlkActionState *common) @@ -3177,6 +3201,27 @@ static void drive_backup_clean(BlkActionState *common) } } +static void drive_backup_cb(BlkActionState *common) +{ + BlkActionCallbackData *cb_data = common->cb_data; + BlockDriverState *bs = cb_data->opaque; + DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common); + + assert(state->bs == bs); + if (bs->job) { + assert(state->job == bs->job); + } + + state->aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(state->aio_context); + + /* Note: We also have the individual job's return code in cb_data->ret */ + backup_transaction_complete(state->job, common->transaction->status); + block_job_decref(state->job); + + aio_context_release(state->aio_context); +} + typedef struct BlockdevBackupState { BlkActionState common; BlockDriverState *bs; @@ -3364,6 +3409,7 @@ static const BlkActionOps actions[] = { .prepare = drive_backup_prepare, .abort = drive_backup_abort, .clean = drive_backup_clean, + .cb = drive_backup_cb, }, [TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP] = { .instance_size = sizeof(BlockdevBackupState), diff --git a/include/block/block_int.h b/include/block/block_int.h index e0d5561..0d26713 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -619,6 +619,14 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target, BlockCompletionFunc *cb, void *opaque, Error **errp); +/* + * backup_transaction_complete: + * @job: The BackupBlockJob that was associated with a transaction. + * @ret: The collective return code for the entire transaction. + * Expects zero for success, non-zero for an error otherwise. + */ +void backup_transaction_complete(BlockJob *job, int ret); + void blk_dev_change_media_cb(BlockBackend *blk, bool load); bool blk_dev_has_removable_media(BlockBackend *blk); void blk_dev_eject_request(BlockBackend *blk, bool force); -- 2.1.0