Re: [PATCH 00/30] virtiofs daemon (base)

[Dr. David Alan Gilbert]

* Daniel P. Berrangé (address@hidden) wrote:
> On Thu, Oct 24, 2019 at 06:59:33AM -0400, Michael S. Tsirkin wrote:
> > On Mon, Oct 21, 2019 at 03:33:57PM +0100, Dr. David Alan Gilbert wrote:
> > > * address@hidden (address@hidden) wrote:
> > > > Patchew URL: https://patchew.org/QEMU/address@hidden/
> > > > 
> > > > 
> > > > 
> > > > Hi,
> > > > 
> > > > This series seems to have some coding style problems. See output below 
> > > > for
> > > > more information:
> > > > 
> > > > Subject: [PATCH 00/30] virtiofs daemon (base)
> > > > Type: series
> > > > Message-id: address@hidden
> > > > 
> > > > === TEST SCRIPT BEGIN ===
> > > > #!/bin/bash
> > > > git rev-parse base > /dev/null || exit 0
> > > > git config --local diff.renamelimit 0
> > > > git config --local diff.renames True
> > > > git config --local diff.algorithm histogram
> > > > ./scripts/checkpatch.pl --mailback base..
> > > 
> > > Expecting checkpatch to be broken here; most of the files
> > > follow FUSE's formatting.
> > > 
> > > Dave
> > 
> > I wonder what do others think about this.
> > One problem with such inconsistencies is that people tend to copy code
> > around, which tends to result in a mess.
> 
> IIUC, most of this code is simpy copied as-is from the fuse or linux
> git repos. I'm wondering what the intention is for it long term ?
> 
> For header files, I would have expected us to be able to compile against
> the -devel package provided by the kernel or fuse packages. I can
> understand if we want to import the headers if the VSOCK additions to
> them are not yet widely available in distros though. If this is the case
> we should put a time limit on how long we'd keep these copied headers
> around for before dropping them. It would be fine to violate QEMU coding
> style in this case as its not code QEMU would "maintain" long term - just
> a read-only import.

The headers are really two types;  one are external definitions, the
other are internal parts of libfuse.  I'd expect to keep the internal
parts long term; teh external parts hmm; where would we pull them in
externally from?

> The source files though, we appear to then be modifying locally, which
> suggests they'll live in our repo forever. In this case I'd expect to
> have compliance with QEMU coding standards.

OK.

> I'm surprised we need to copy so much in from fuse though. Is there a
> case to be made for fuse to provide a library of APIs for people who
> are building fuse daemons to link against, instead of copy & fork ?

libfuse *is* such a library; but it preserves ABI compliance; it's
intention is to be used to build filesystem implementations on top of -
and that's got a fairly good separation;  however changing the fuse
transport, and security models is much more invasive than it was
designed for.

Dave

> Regards,
> Daniel
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--
Dr. David Alan Gilbert / address@hidden / Manchester, UK