Commit 1fdd4b7b authored by Fam Zheng's avatar Fam Zheng Committed by Kevin Wolf
Browse files

block: Add "drained begin/end" for transactional backup 



This ensures the atomicity of the transaction by avoiding processing of
external requests such as those from ioeventfd.

Move the assignment to state->bs up right after bdrv_drained_begin, so
that we can use it in the clean callback. The abort callback will still
check bs->job and state->job, so it's OK.

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent da763e83

blockdev.c

+8 −1
Original line number Diff line number Diff line
@@ -1684,9 +1684,16 @@ static void drive_backup_prepare(BlkTransactionState *common, Error **errp) 
        return;

    }



    if (!blk_is_available(blk)) {

        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);

        return;

    }



    /* AioContext is released in .clean() */

    state->aio_context = blk_get_aio_context(blk);

    aio_context_acquire(state->aio_context);

    bdrv_drained_begin(blk_bs(blk));

    state->bs = blk_bs(blk);



    qmp_drive_backup(backup->device, backup->target,

                     backup->has_format, backup->format,
@@ -1702,7 +1709,6 @@ static void drive_backup_prepare(BlkTransactionState *common, Error **errp) 
        return;

    }



    state->bs = blk_bs(blk);

    state->job = state->bs->job;

}
@@ -1722,6 +1728,7 @@ static void drive_backup_clean(BlkTransactionState *common) 
    DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);



    if (state->aio_context) {

        bdrv_drained_end(state->bs);

        aio_context_release(state->aio_context);

    }

}