On Wed, Nov 21, 2018 at 05:55:40PM +0100, u-x417_at_aetey.se wrote:
> 
> (Don't most file systems need their specific kernel modules? Good or not
> but isn't this the status quo?)
> 

A lot of them are tradition... I am pretty sure that NFS on Linux is all
userland.

> > NetBSD has just discussed whether to
> > remove coda kernel support, as it has almost no users.  For now, it is
> > staying.
> 
> Oh! I depend on Coda being available on NetBSD. Hope it continues to.
> 

Well, there is at least one developer that uses it....So lossage get
noticed at some point, depending on how much hack time they have.

> This is imho what really should be fixed, FUSE or not.
> 
> With all due and enormous respect to the early developers, this
> communication channel is flaky, both in design (ioctl is a really bad
> tool, given that we handle a pure IPC/RPC between user processes and
> venus; the only role of the kernel is to help process authentication,
> not having to be aware of the data to be passed) and as a result also
> flaky in the implementation.
> 

No, the kernel module does a lot more than that, at least on NetBSD,
the kernel module hooks into the UFS code to perform directory
processing and a few other things.  In fact this hooking resulted in a
very long standing bug in the NetBSD venus process where coda and ufs
disagreed on the size of a directory block size - this caused directory
entries to "disappear".

> 
> Frankly I doubt whether FUSE would make a big difference. We have already
> kernel support for Coda in Linux, NetBSD, FreeBSD. Which platform would
> you look forward to, which has a usable FUSE but a different kernel than
> one of the above?
> 

>From wikipedia - OpenBSD, OpenSolaris, Minix 3, Android, MacOS.

If FUSE support was built into venus then, potentially, coda would be
able to run on these operating systems too... I don't know how useful it
would be but Coda on a phone would be pretty cool ;)

-- 
Brett Lymn
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