Am 21.10.2015 um 04:06 hat Fam Zheng geschrieben:
> This ensures the atomicity of the transaction by avoiding processing of
> external requests such as those from ioeventfd.
>
> state->bs is assigned right after bdrv_drained_begin. Because it was
> used as the flag for deletion or not in abort, now we need a separate
> flag - InternalSnapshotState.created.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> blockdev.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 52f44b2..92c2d0d 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1370,6 +1370,7 @@ typedef struct InternalSnapshotState {
> BlockDriverState *bs;
> AioContext *aio_context;
> QEMUSnapshotInfo sn;
> + bool created;
> } InternalSnapshotState;
>
> static void internal_snapshot_prepare(BlkTransactionState *common,
> @@ -1407,6 +1408,8 @@ static void
> internal_snapshot_prepare(BlkTransactionState *common,
> /* AioContext is released in .clean() */
> state->aio_context = blk_get_aio_context(blk);
> aio_context_acquire(state->aio_context);
> + state->bs = blk_bs(blk);
> + bdrv_drained_begin(state->bs);
>
> if (!blk_is_available(blk)) {
> error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
The blk_is_available() check must come first, otherwise we can call
bdrv_drained_begin(NULL) and bdrv_drained_begin() doesn't accept that.
Kevin
