Various FreeBSD Coda fixes

[Robert Watson]

On Sat, 19 Jan 2008, Robert Watson wrote:

> I'm not sure if these can be MFC'd before 7.0, but will ask re@ if we can 
> fit them in.  Certainly, it's better than panicking, which is a relatively 
> likely scenario with what's currently in RELENG_7.

I've merged these, and a couple more since then, to RLEENG_7, and will request 
an MFC to RELENG_7_0 to include them in the forthcoming FreeBSD 7.0.  It would 
be very helpful, if you have a 7.x box, if you could update to the head of 
RELENG_7 to pick up these fixes, and test with Coda with them.

I'm aware of four outstanding problems:

- Rune has reported a hang with X11 and Coda, but we haven't yet been able to
   track it down much yet -- might not be related to Coda.

- Linux binaries have problems listing directories in Coda under Linux
   emulation.  Won't be fixed for 7.0.

- ".." and "." sometimes appear to have problems in the root directory of the
   root volume of a realm (i.e., /coda/testserver.coda.cs.cmu.edu).  I'm not
   sure if this is a Coda client bug or a kernel bug, quite possibly the
   latter.  This most likely won't be fixed for 7.0 unless it jumps out at me
   tomorrow.

- getpwd() appears to have problems, possibly related to the previous bug if
   it's unable to recurse to the root.  Because Coda doesn't use the global
   VFS namecache, the __getcwd() system call which is often able to resolve the
   current directly doesn't work with Coda; the userspace implementation walks
   to the root looking for the child directory in each parent, which can have
   problems if stat() and inode numbers are inconsistent, or if there's a
   broken ".." step.  Ditto on this most likely not being fixed for 7.0.

Any other problems, especially panics with the backport of the other fixes to 
RELENG_7, are very much fair game, but having the reports by the end of 
Tuesday would be extremely helpful.

Robert N M Watson
Computer Laboratory
University of Cambridge