Re: [9fans] FS for sharing between Linux and Plan 9

[David du Colombier <0intro@gmail.com>]

> From this, I understand that you've concocted an alpha (beta?)
> version of fossil for plan9port.

Actually, it was an easy job. I did it in few hours and, as
you can see, the modifications were trivial, thank to the
very good environment offered by plan9port.

It's unfinished just because I haven't spent much time on the
remaining issues.

> I'm wondering: Is the on-disk format of this "modified Fossil"
> compatible with P9 fossil?

Yes of course. The file system format is identical.
Actually, the modifications are only internal and there
are no user-visible changes.

Keep in mind I did these changes primarily for Plan 9. My goal
was firstly to get rid of the liboventi and secondly to benefit
from the libthread to replace locks with channels.

The version currently available is the first part. It doesn't
address any of the known Fossil issues, like the well-known
deadlock on flushwait, since I still haven't figured how to
properly fix this problem using the current locking mechanisms.

I am currently working on the second part and I already fixed
these problems by replacing some locks with channels, but it
is currently too experimental to be distributed.

It just happened I ported my modified Fossil to plan9port and
not the original one.

> If so, it might work as the Plan9-Linux-universal file system the
> OP's looking for after all (less any bugs he might encounter in such
> young code).

Yes, it allows some Unix to read and write to a Plan 9 file system.

> For the OP's purposes (sharing an fs between Plan 9 and Linux), this
> might actually be tenable.  The fossil console is typically used for
> administrative tasks, not generally during routine use (i.e., just
> storing and reading back files).  If the OP's needs for fossilcons can
> wait until he's at a P9 box, it might be a practical setup... at least
> until the console is ported.

The lack of console is more problematic than you think.

It's not a problem when you start Fossil, because you can use options
-f and -c to execute commands from a file or command-line.
However, you will not be able, for example, to execute "sync" or "halt"
on a running file system, which is somewhat embarrassing.

That's why I want to fix this problem.

--
David du Colombier