Coda File System

Coda and Linux 2.6 kernels

From: Ivan Popov <pin_at_medic.chalmers.se>
Date: Sun, 25 Sep 2005 15:51:41 +0200
Hello,

is there anybody running the most recent kernels, to be able to check
their behaviour?

I made a test on 2.6.9, compiling Coda module 6.2 for Red Hat Enterprise
Linux 4 (their custom kernel lacks the module) and running a Coda client
(6.0.11).

Unfortunately, the result is the same as last time I used 2.6.8 this summer,
shell pipelines lead to failures at running some parts of the pipe.

It looks like concurrent lookups on a user space ("slow") filesystem are prone
to race conditions in 2.6. I have reasons to believe Jan's analysis which says
that it is the kernel's, not Coda's fault.

-------------------------------------------------------------
~$ uname -a
Linux xxx.yyy.chalmers.se 2.6.9-11.EL #1 Fri May 20 18:17:57 EDT 2005 i686 unknown unknown GNU/Linux
~$ cp /bin/cat /coda/testserver.coda.cs.cmu.edu/playground/c
~$ export PATH=${PATH}:/coda/testserver.coda.cs.cmu.edu/playground
~$ type c
c is /coda/testserver.coda.cs.cmu.edu/playground/c
~$ echo abc | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | wc
      0       0       0                       <<----
~$ echo abc | c | c | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | c | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | wc
      0       0       0                       <<----
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | c | wc
      0       0       0                       <<----
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | c | wc
      0       0       0                       <<----
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | c | wc
      0       0       0                       <<----
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | c | wc
      0       0       0                       <<----
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | c | wc
      1       1       4
~$ echo abc | c | c | c | c | c | c | c | c | c | c | c | c | wc
      0       0       0                       <<----
~$
-------------------------------------------------------------

To give an idea about the machine where I tested:
-------------------------------------------------------------
~$ cat /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Pentium(R) 4 CPU 1.80GHz
stepping        : 4
cpu MHz         : 1816.972
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
bogomips        : 3579.90
-------------------------------------------------------------

Anybody who can check/confirm on the latest kernels?
(be careful if running things from playground! you can be easily troyaned,
better use some private area on Coda)

Regards,
--
Ivan
Received on 2005-09-25 09:55:53