Re: [Libguestfs] [PATCH nbdkit v2 2/7] tls-fallback: Fix filter for new .block_size callback
On 02/17/22 17:56, Eric Blake wrote:
On Thu, Feb 17, 2022 at 04:41:31PM +0000, Richard W.M. Jones wrote:
> On Thu, Feb 17, 2022 at 10:30:13AM -0600, Eric Blake wrote:
>> On Thu, Feb 17, 2022 at 02:36:43PM +0000, Richard W.M. Jones wrote:
>>> This filter doesn't call the next_open function in the non-TLS case,
>>> and therefore it never opens the plugin. This leaves the internal
>>> state of nbdkit a bit strange. There is no plugin context allocated,
>>> and the last filter in the chain has a context c_next pointer of NULL.
>>>
>>> This works, provided we intercept every possible callback, check the
>>> non-TLS case, and prevent it from calling the next function (because
>>> it would dereference the NULL c_next).
>>>
>>> To avoid a crash in backend_block_size we must therefore provide a
>>> .block_size callback in this filter.
>>> ---
>>> filters/tls-fallback/tls-fallback.c | 15 +++++++++++++++
>>> 1 file changed, 15 insertions(+)
>>
>> ACK.
>>
>> Would you like to squash this in, and/or have me commit this separately?
>
> I was actually thinking about squashing my patches 1-4 together.
> They're all really the same change, but I kept them separate for ease
> of review. What do you think?
I think patch#2 should be squashed into patch#1 (and the commit messages
should be merged). However, I'd suggest keeping each of patches #3 and
#4 separate.
Patch#2 fixes a bug exposed by patch#1, so patch#1 in itself doesn't
just start introducing a feature, but also introduces (effectively) a
bug (a crash), temporarily. That should be avoided. However, erecting a
feature in multiple stages (patches #3 and #4) is what all feature
series should do. It's natural that a feature doesn't (fully) work until
the end of the series.
Also, "ease of review" is not necessarily a one-time benefit; if we need
to look at these patches in some years, I think we'll appreciate a fine
granularity in the git history.
Thanks,
Laszlo
Seems reasonable (I'll confirm it again when I get through reviewing 4).
>
> But I think this patch:
>
>> commit 8c00ca2fe418aeecf0818feed227a72e76d87f18
>> Author: Eric Blake <eblake(a)redhat.com>
>> Date: Thu Feb 17 10:24:50 2022 -0600
>>
>> tls-fallback: Enhance comments about required callbacks
> ... would stay separate, and you can push it before or after.
Before - it is now commit 8c00ca2f ;)