From: Herbert Poetzl (herbert_at_13thfloor.at)
Date: Thu 06 Nov 2003 - 03:24:40 GMT
On Wed, Nov 05, 2003 at 11:02:56AM +0100, Jan Zuchhold wrote:
> > > There seems to be a problem with using nfs shares in a vserver with
> > > vs1.00. It appears that it is related to file locking.
> > >
> > > The share is mounted like this in the vserver startup script:
> > >
> > > /usr/sbin/chbind --ip 192.168.1.145 --bcast 192.168.1.255 mount
> > > -t nfs fileserver:/home /var/lib/vservers/$2/home
> > >
> > > After mounting the share it seems to work correctly (cd/ls/touch showing
> > > no problems).
> > >
> > > When I start a process (in my case it's eclipse in jvm 1.4.1) which tries
> > > to lock a file on that nfs share, it goes to state D ('uninterruptible
> > > sleep') and cannot be killed. Any other process which tries to access the
> > > share goes to state D as well.
> >
> > hmm, could you try to reproduce this without eclipse/jvm?
> > (some small C programm or perl script will do)
>
> I could track down the problem to the fcntl64 syscall.
> Strace output:
> 10:36:19 fcntl64(3, F_SETLKW64, {type=F_WRLCK, whence=SEEK_SET, start=0,
> len=0}
>
> I attached a small perl script to reproduce this.
okay, will look into it today ...
> After that syscall the process goes to state D and if the lock would be
> granted by the nfs server (if it is not locked already), there is no further
> access possible to that nfs share, even umount -f does not work.
> As far as I can tell, if the file is already locked by another process, it
> just waits, as I would expect.
>
>
> > > This problem does not appear in ctx-17c (the last version I tried
> > > before), although the first three syslog messages appear as well.
> >
> > maybe the patch isn't the only variable in this game,
> > maybe you patched another (newer?) kernel with v1.00?
>
> (sorry I forgot to include the versions):
> Both 2.4.22, same .config, just the vserver patch is different.
> Host is debian stable/woody, vserver is debian unstable/sid.
good, thanks for for narrowing it down ..
> Thank you,
> Jan
>
> --
> #!/usr/bin/perl
>
> use Fcntl;
>
> open FH, ">locktest.lock" or die "Cannot open $fn: $!";
> flock FH, 2;
> print "flock works...\n";
>
> print "Testing fcntl...\n";
> @list = (F_WRLCK,0,0,0,0); # exclusive write lock, entire file
> $struct = pack("SSLLL",@list);
> fcntl(FH,&F_SETLKW,$struct) or die("cannot lock because: $!\n");
>
> # With vs1.00 I don't get here
>
> print FH "blabla";
>
> close FH;
>
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