Messages in this thread | | | Date | Sun, 26 Jan 2003 14:02:00 -0200 | From | Christian Reis <> | Subject | Re: NFS client locking hangs for period |
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On Sat, Jan 25, 2003 at 02:54:09PM +1100, Neil Brown wrote: > Hmmm. So you have several clients all mounting the same root > filesystem, and mounting it writable? That doesn't sound like a plan > for success. How do you make sure the clients don't tread over each > other when using /etc files?
The truth is few (broken wrt the FHS) programs actually write to /etc. I have set up everything so nothing is written to in /etc, and it actually works very well (have to use a special init(8) that doesn't write to /etc/ioctl.save). This setup has been running for almost a year now, with the locking problem being the only one left to fix.
> I suspect that what you really want is to mount root read-only, or > mount separate roots for each client, and then in either case to mount > with the "nolock" flag.
Well, mounting root read-only is a good idea but it sacrifices being able to administer the system from any station, and it also puts a lot of burden on me to fix *all* programs to not write to anywhere on it. This shouldn't be too hard, but we're still just working around the bug, which I would really like to identify and fix.
> I suspect that your problem is related to the client trying to do > locking, but no having statd running on the client.
I am 100% positive statd runs on every single client. This problem here only happens spuriously. It goes away when I restart nfsd and mountd (in that order). It really does look like a bug <wink>
> You cannot meaningfully do locking on an NFS mounted root filesystem. > Infact, I think it would be good if the default mount options for nfs > root included nolock... and if I read fs/nfs/nfsroot.c:root_nfs_name > correctly, nolock is the default. Are you overriding that default > be explicitly setting "lock"??
Nope. I've just tested and the default (specifying no lock option upon bootup) really is nolock:
/dev/root on / type nfs (rw,v3,rsize=8192,wsize=8192,hard,udp,nolock,addr=192.168.99.4)
I wonder why you can't do locking on NFS root (if it's a current limitation of if it doesn't make sense).
But I also think this problem shouldn't be happening if no locking was going on. And when I checked using nlm_debug it sure did seem locking was being used. What do you make of it?
Take care, -- Christian Reis, Senior Engineer, Async Open Source, Brazil. http://async.com.br/~kiko/ | [+55 16] 261 2331 | NMFL - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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