Arla 0.7.2 returns stale cached metadata on Linux 2.0

[Aaron M. Ucko]

At least on Linux 2.0.34, Arla 0.7.2 doesn't appear to notice changes
made to vnodes on other machines, though it does notice changes to the
actual data:

[create foo as an empty file on another machine]

#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; ls -l foo
-rw-r--r--   1 amu      mit             0 Jul 19 13:55 foo
#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; cat foo
#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; date
Sun Jul 19 13:56:00 EDT 1998

[run date >> foo on the second machine]

#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; ls -l foo
-rw-r--r--   1 amu      mit             0 Jul 19 13:55 foo
#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; cat foo
Sun Jul 19 13:56:07 EDT 1998
#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; date
Sun Jul 19 13:57:58 EDT 1998
#amu at dorm-s-007-m:/afs/athena.mit.edu/user/a/m/amu/Private
; ls -l foo
-rw-r--r--   1 amu      mit             0 Jul 19 13:55 foo

-- 
Aaron M. Ucko, KB1CJC <amu at mit.edu> (finger amu at monk.mit.edu)