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From: Max Reitz <mreitz@redhat.com>
To: John Snow <jsnow@redhat.com>,
	qemu-block@nongnu.org, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, Markus Armbruster <armbru@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 7/8] block/backup: support bitmap sync modes for non-bitmap backups
Date: Wed, 10 Jul 2019 18:48:47 +0200	[thread overview]
Message-ID: <01ddc5da-c4e1-864e-ee0d-e39036d6d4dd@redhat.com> (raw)
In-Reply-To: <20190710010556.32365-8-jsnow@redhat.com>


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On 10.07.19 03:05, John Snow wrote:
> Accept bitmaps and sync policies for the other backup modes.
> This allows us to do things like create a bitmap synced to a full backup
> without a transaction, or start a resumable backup process.
> 
> Some combinations don't make sense, though:
> 
> - NEVER policy combined with any non-BITMAP mode doesn't do anything,
>   because the bitmap isn't used for input or output.
>   It's harmless, but is almost certainly never what the user wanted.
> 
> - sync=NONE is more questionable. It can't use on-success because this
>   job never completes with success anyway, and the resulting artifact
>   of 'always' is suspect: because we start with a full bitmap and only
>   copy out segments that get written to, the final output bitmap will
>   always be ... a fully set bitmap.
> 
>   Maybe there's contexts in which bitmaps make sense for sync=none,
>   but not without more severe changes to the current job, and omitting
>   it here doesn't prevent us from adding it later.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  block/backup.c       |  8 +-------
>  blockdev.c           | 22 ++++++++++++++++++++++
>  qapi/block-core.json |  6 ++++--
>  3 files changed, 27 insertions(+), 9 deletions(-)

[...]

> diff --git a/blockdev.c b/blockdev.c
> index f0b7da53b0..bc152f8e0d 100644
> --- a/blockdev.c
> +++ b/blockdev.c

[...]

> +    if (!backup->has_bitmap && backup->has_bitmap_mode) {
> +        error_setg(errp, "Cannot specify Bitmap sync mode without a bitmap");

Any reason for capitalizing the first “Bitmap”?

With a reason or it fixed:

Reviewed-by: Max Reitz <mreitz@redhat.com>


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  reply	other threads:[~2019-07-10 16:50 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-10  1:05 [Qemu-devel] [PATCH 0/8] bitmaps: allow bitmaps to be used with full and top John Snow
2019-07-10  1:05 ` [Qemu-devel] [PATCH 1/8] iotests/257: add Pattern class John Snow
2019-07-10 15:10   ` Max Reitz
2019-07-10 16:26   ` Max Reitz
2019-07-10 17:34     ` John Snow
2019-07-10  1:05 ` [Qemu-devel] [PATCH 2/8] iotests/257: add EmulatedBitmap class John Snow
2019-07-10 15:47   ` Max Reitz
2019-07-10 17:36     ` John Snow
2019-07-10  1:05 ` [Qemu-devel] [PATCH 3/8] iotests/257: Refactor backup helpers John Snow
2019-07-10 16:04   ` Max Reitz
2019-07-10 17:52     ` John Snow
2019-07-10 20:17       ` Max Reitz
2019-07-10  1:05 ` [Qemu-devel] [PATCH 4/8] block/backup: hoist bitmap check into QMP interface John Snow
2019-07-10 16:11   ` Max Reitz
2019-07-10 17:57     ` John Snow
2019-07-10 20:19       ` Max Reitz
2019-07-10  1:05 ` [Qemu-devel] [PATCH 5/8] iotests/257: test API failures John Snow
2019-07-10 16:22   ` Max Reitz
2019-07-10 18:00     ` John Snow
2019-07-10  1:05 ` [Qemu-devel] [PATCH 6/8] block/backup: issue progress updates for skipped regions John Snow
2019-07-10 16:36   ` Max Reitz
2019-07-10 18:20     ` John Snow
2019-07-10 20:30       ` Max Reitz
2019-07-10 20:47         ` John Snow
2019-07-10 20:53           ` Max Reitz
2019-07-10  1:05 ` [Qemu-devel] [PATCH 7/8] block/backup: support bitmap sync modes for non-bitmap backups John Snow
2019-07-10 16:48   ` Max Reitz [this message]
2019-07-10 18:32     ` John Snow
2019-07-10 20:39       ` Max Reitz
2019-07-10  1:05 ` [Qemu-devel] [PATCH 8/8] iotests/257: test traditional sync modes John Snow
2019-07-10 17:14   ` Max Reitz
2019-07-10 19:00     ` John Snow
2019-07-10 20:46       ` Max Reitz
     [not found]         ` <2f221513-f173-8d9f-a3b2-d790ef6f6f51@redhat.com>
2019-07-11 12:37           ` Max Reitz
2019-07-11 17:58             ` John Snow

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