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TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 762EA30833A6; Wed, 10 Jul 2019 18:32:55 +0000 (UTC) Received: from [10.18.17.130] (dhcp-17-130.bos.redhat.com [10.18.17.130]) by smtp.corp.redhat.com (Postfix) with ESMTP id B4C5198BA; Wed, 10 Jul 2019 18:32:54 +0000 (UTC) To: Max Reitz , qemu-block@nongnu.org, qemu-devel@nongnu.org References: <20190710010556.32365-1-jsnow@redhat.com> <20190710010556.32365-8-jsnow@redhat.com> <01ddc5da-c4e1-864e-ee0d-e39036d6d4dd@redhat.com> From: John Snow Openpgp: preference=signencrypt Autocrypt: addr=jsnow@redhat.com; prefer-encrypt=mutual; keydata= mQINBFTKefwBEAChvwqYC6saTzawbih87LqBYq0d5A8jXYXaiFMV/EvMSDqqY4EY6whXliNO IYzhgrPEe7ZmPxbCSe4iMykjhwMh5byIHDoPGDU+FsQty2KXuoxto+ZdrP9gymAgmyqdk3aV vzzmCa3cOppcqKvA0Kqr10UeX/z4OMVV390V+DVWUvzXpda45/Sxup57pk+hyY52wxxjIqef rj8u5BN93s5uCVTus0oiVA6W+iXYzTvVDStMFVqnTxSxlpZoH5RGKvmoWV3uutByQyBPHW2U 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qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/10/19 12:48 PM, Max Reitz wrote: > 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 back= up >> 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=3DNONE is more questionable. It can't use on-success because th= is >> 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=3Dnone, >> 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 >> --- >> block/backup.c | 8 +------- >> blockdev.c | 22 ++++++++++++++++++++++ >> qapi/block-core.json | 6 ++++-- >> 3 files changed, 27 insertions(+), 9 deletions(-) >=20 > [...] >=20 >> diff --git a/blockdev.c b/blockdev.c >> index f0b7da53b0..bc152f8e0d 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >=20 > [...] >=20 >> + if (!backup->has_bitmap && backup->has_bitmap_mode) { >> + error_setg(errp, "Cannot specify Bitmap sync mode without a b= itmap"); >=20 > Any reason for capitalizing the first =E2=80=9CBitmap=E2=80=9D? >=20 > With a reason or it fixed: >=20 > Reviewed-by: Max Reitz >=20 Hanging around Germans too much? Actually, I can explain why: because a "bitmap" is a generic term, but whenever I capitalize it as "Bitmap" I am referring to a Block Dirty Bitmap which is a specific sort of thing. I do this unconsciously. But in that case, I should actually be consistent in the interface (and docstrings and docs and error strings) and always call it that specific thing, which I don't. "bitmap" is probably more correct for now, but I ought to go through all the interface and make it consistent in some way or another. (Actually: I'd like to see if I can't rename the "BdrvDirtyBitmap" object to something more generic and shorter so I can rename many of the functions we have something shorter. Because the structure is "BdrvDirtyBitmap", there's some confusion when we name functions like bdrv_dirty_bitmap_{verb} because it's not clear if this is a bdrv function that does something with dirty bitmaps, or if it's a "BdrvDirtyBitmap" function that does something with that object. I guess that seems like a subtle point, but it's why the naming conventions in dirty-bitmap.c are all over the place. I think at one point, the idea was that: bdrv_{verb}_dirty_bitmap was an action applied to a BDS that happened to do something with dirty bitmaps. bdrv_dirty_bitmap_{verb} was an action that applied to a "BdrvDirtyBitmap". Crystal clear and not confusing at all, right? It'd be nice to have functions that operate on a node be named bdrv_dbitmap_foo() and functions that operate on the bitmap structure itself named just dbitmap_bar(). Would it be okay if I named them such a thing, I wonder? we have "bitmap" and "hbitmap" already, I could do something like "dbitmap" for "dirty bitmap" or some such. Kind of an arbitrary change I admit, but I'm itching to do a big spring cleaning in dirty-bitmap.c right after this series is done.)