Re: [PATCH v15 13/13] block: apply COR-filter to block-stream jobs

[Max Reitz <mreitz@redhat.com>]

On 16.12.20 07:17, Vladimir Sementsov-Ogievskiy wrote:
> From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> 
> This patch completes the series with the COR-filter applied to
> block-stream operations.
> 
> Adding the filter makes it possible in future implement discarding
> copied regions in backing files during the block-stream job, to reduce
> the disk overuse (we need control on permissions).
> 
> Also, the filter now is smart enough to do copy-on-read with specified
> base, so we have benefit on guest reads even when doing block-stream of
> the part of the backing chain.
> 
> Several iotests are slightly modified due to filter insertion.
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   block/stream.c             | 105 ++++++++++++++++++++++---------------
>   tests/qemu-iotests/030     |   8 +--
>   tests/qemu-iotests/141.out |   2 +-
>   tests/qemu-iotests/245     |  20 ++++---
>   4 files changed, 80 insertions(+), 55 deletions(-)

[...]

> diff --git a/tests/qemu-iotests/141.out b/tests/qemu-iotests/141.out
> index 08e0aecd65..028a16f365 100644
> --- a/tests/qemu-iotests/141.out
> +++ b/tests/qemu-iotests/141.out
> @@ -99,7 +99,7 @@ wrote 1048576/1048576 bytes at offset 0
>   {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "job0"}}
>   {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "job0"}}
>   {'execute': 'blockdev-del', 'arguments': {'node-name': 'drv0'}}
> -{"error": {"class": "GenericError", "desc": "Node drv0 is in use"}}
> +{"error": {"class": "GenericError", "desc": "Node 'drv0' is busy: block device is in use by block job: stream"}}
>   {'execute': 'block-job-cancel', 'arguments': {'device': 'job0'}}
>   {"return": {}}
>   {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "aborting", "id": "job0"}}

Amusing side note: This context matches two places in 141.out.  With 
0e720781282 (which requires two contextual whitespace tweaks), the file 
gets longer, so the line number doesn’t match anymore.  git then tries 
to apply the context to the first match (which is closer to line 99), 
which is wrong.

First time I had something like that happen, actually.

Max