Re: [Qemu-devel] [PATCH v2 2/2] iotests: New test 223 for exporting dirty bitmap over NBD

[Vladimir Sementsov-Ogievskiy]

02.07.2018 22:14, Eric Blake wrote:
> Although this test is NOT a full test of image fleecing (as it
> intentionally uses just a single block device directly exported
> over NBD, rather than trying to set up a blockdev-backup job with
> multiple BDS involved), it DOES prove that qemu as a server is
> able to properly expose a dirty bitmap over NBD.
>
> When coupled with image fleecing, it is then possible for a
> third-party client to do an incremental backup by using
> qemu-img map with the x-dirty-bitmap option to learn which parts
> of the file are dirty (perhaps confusingly, they are the portions
> mapped as "data":false - which is part of the reason this is
> still in the x- experimental namespace), along with another
> normal client (perhaps 'qemu-nbd -c' to expose the server over
> /dev/nbd0 and then just use normal I/O on that block device) to
> read the dirty sections.
>
> Signed-off-by: Eric Blake <address@hidden>
> ---
>   tests/qemu-iotests/223     | 138 +++++++++++++++++++++++++++++++++++++++++++++
>   tests/qemu-iotests/223.out |  49 ++++++++++++++++
>   tests/qemu-iotests/group   |   1 +
>   3 files changed, 188 insertions(+)
>   create mode 100755 tests/qemu-iotests/223
>   create mode 100644 tests/qemu-iotests/223.out
>
> diff --git a/tests/qemu-iotests/223 b/tests/qemu-iotests/223
> new file mode 100755
> index 00000000000..b63b7a4f9e1
> --- /dev/null
> +++ b/tests/qemu-iotests/223
> @@ -0,0 +1,138 @@
> +#!/bin/bash

[...]

> +
> +echo
> +echo "=== End NBD server ==="
> +echo
> +
> +_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-remove",
> +  "arguments":{"name":"n"}}' "return"
> +_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "return"

blockdev-del is not necessary?

with or without:

Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>


--
Best regards,
Vladimir