Re: [PULL 0/8] 9p queue 2021-10-27

[Christian Schoenebeck]

On Mittwoch, 27. Oktober 2021 18:48:10 CEST Philippe Mathieu-Daudé wrote:
> On 10/27/21 18:21, Christian Schoenebeck wrote:
> > On Mittwoch, 27. Oktober 2021 17:36:03 CEST Philippe Mathieu-Daudé wrote:
> >> Hi Christian,
> >> 
> >> On 10/27/21 16:05, Christian Schoenebeck wrote:
> >>> On Mittwoch, 27. Oktober 2021 15:18:33 CEST Christian Schoenebeck wrote:
> >>>> The following changes since commit
> > 
> > 931ce30859176f0f7daac6bac255dae5eb21284e:
> >>>>   Merge remote-tracking branch
> >>>>   'remotes/dagrh/tags/pull-virtiofs-20211026'
> >>>> 
> >>>> into staging (2021-10-26 07:38:41 -0700)
> >>>> 
> >>>> are available in the Git repository at:
> >>>>   https://github.com/cschoenebeck/qemu.git tags/pull-9p-20211027
> >>>> 
> >>>> for you to fetch changes up to 
7e985780aaab93d2c5be9b62d8d386568dfb071e:
> >>>>   9pfs: use P9Array in v9fs_walk() (2021-10-27 14:45:22 +0200)
> >>>> 
> >>>> ----------------------------------------------------------------
> >>>> 9pfs: performance fix and cleanup
> >>>> 
> >>>> * First patch fixes suboptimal I/O performance on guest due to
> >>>> previously
> >>>> 
> >>>>   incorrect block size being transmitted to 9p client.
> >>>> 
> >>>> * Subsequent patches are cleanup ones intended to reduce code
> >>>> complexity.
> >>>> 
> >>>> ----------------------------------------------------------------
> >>>> 
> >>>> Christian Schoenebeck (8):
> >>>>       9pfs: fix wrong I/O block size in Rgetattr
> >>>>       9pfs: deduplicate iounit code
> >>>>       9pfs: simplify blksize_to_iounit()
> >>>>       9pfs: introduce P9Array
> >>>>       fsdev/p9array.h: check scalar type in P9ARRAY_NEW()
> >>>>       9pfs: make V9fsString usable via P9Array API
> >>>>       9pfs: make V9fsPath usable via P9Array API
> >>>>       9pfs: use P9Array in v9fs_walk()
> >>>>  
> >>>>  fsdev/9p-marshal.c |   2 +
> >>>>  fsdev/9p-marshal.h |   3 +
> >>>>  fsdev/file-op-9p.h |   2 +
> >>>>  fsdev/p9array.h    | 160
> >>>> 
> >>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++ hw/9pfs/9p.c
> >>>> 
> >>>> 70 +++++++++++++----------
> >>>> 
> >>>>  5 files changed, 208 insertions(+), 29 deletions(-)
> >>>>  create mode 100644 fsdev/p9array.h
> >>> 
> >>> Regarding last 5 patches: Daniel raised a concern that not using
> >>> g_autoptr
> >>> would deviate from current QEMU coding patterns:
> >>> https://lists.gnu.org/archive/html/qemu-devel/2021-10/msg00081.html
> >>> 
> >>> Unfortunately I saw no way to address his concern without adding
> >>> unnecessary code complexity, so I decided to make this a 9p local type
> >>> (QArray -> P9Array) for now, which can easily be replaced in future
> >>> (e.g.
> >>> when there will be something appropriate on glib side).
> >> 
> >> Hmm various patches aren't reviewed yet... In particular
> >> patch #5 has a Suggested-by tag without Reviewed-by, this
> >> looks odd.
> >> 
> >> See https://wiki.qemu.org/Contribute/SubmitAPullRequest:
> >>   Don't send pull requests for code that hasn't passed review.
> >>   A pull request says these patches are ready to go into QEMU now,
> >>   so they must have passed the standard code review processes. In
> >>   particular if you've corrected issues in one round of code review,
> >>   you need to send your fixed patch series as normal to the list;
> >>   you can't put it in a pull request until it's gone through.
> >>   (Extremely trivial fixes may be OK to just fix in passing, but
> >>   if in doubt err on the side of not.)
> > 
> > There are in general exactly two persons adding their RBs to 9p patches,
> > which is either Greg or me, and Greg made it already clear that he barely
> > has time for anything above trivial set.
> > 
> > So what do you suggest? You want to participate and review 9p patches?
> 
> Well I am a bit surprised...
> 
> $ git log --oneline \
>     --grep='Reviewed-by: Philippe Mathieu-Daudé' -- hw/9pfs/ | wc -l
> 18
> 
> I also reviewed patch #3 if this pull request...
> 
> 
> Now I see you posted this 4 times in 2 months, so indeed eventual
> reviewers had plenty of time to look at your patches.
> 
> Note I haven't said I'd NAck your pull request, I noticed your own
> concern wrt Daniel comment, so I looked at the patch and realized
> it was not reviewed, and simply said this is this is odd.
> 
> Regards,
> 
> Phil.

Philippe, of course I understand why this looks odd to you, and yes you 
reviewed that particular patch. But the situation on the 9p front is like this 
for >2 years now: people quickly come by to nack patches, but even after 
having addressed their concerns they barely add their RBs afterwards. That 
means I am currently forced to send out PRs without RBs once in a while.

The mentioned 5 patches look like overkill on first sight, but they are just 
intended as preparatory ones. I actually should fix a protocol implementation 
deficit in "Twalk" request handling, and that in turn means I will have to add 
complexity to function v9fs_walk(). But before even daring to do so, I should 
get rid of as much of complexity as possible. Because we already had a bunch 
of issues in that function before. I believe these are trivial 5 patches. But 
I can also accompany them with test cases if somebody is worried.

Greg, I could also drop them now, but the general issue will retain: Reality 
is that I am the only person working on 9p right now and a fact that I cannot 
change. The rest is for other people to decide.

Best regards,
Christian Schoenebeck