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From: sjoerd@cwi.nl (Sjoerd Mullender)
Newsgroups: comp.sys.alliant
Subject: Re: problems porting amd to Concentrix 5.5.02
Message-ID: <1944@charon.cwi.nl>
Date: 9 Aug 90 14:57:46 GMT
References: <1926@charon.cwi.nl>
Sender: news@cwi.nl
Lines: 30

sjoerd@cwi.nl (Sjoerd Mullender) (that's me) writes:

>I am trying to port amd (Jan-Simon Pendry's automount daemon) to the
>Alliant.  When we were running Concentrix 5.0.0, I had no problems doing
>that, but since we are running 5.5.02, the automount daemon stopped
>working.
>By using adb I found that both amd and /etc/mount do a mount system call
>with the exact same arguments.  The difference is that /etc/mount succeeds
>in mounting the remote directory and amd fails.  Mount returns with an
>errno of EDEADLK "Deadlock situation detected/avoided".  This error is
>not documented in the manual.

I have seen two followups on this message.  In one, Peter Lamb suggested
the `program' mount type.  I have tried that, but I got the same error.
Ric Werme poked around a bit and found that EDEADLK involves interlocking
file system accesses.
What I think is happeing is the following.  Amd mounts a directory, using
the NFS mount options and acts as the nfs server for that directory.  In my
case, the directory is called /hosts.  Now when I access a directory inside
/hosts, the kernel sends a message to the nfs server of /hosts (that is: amd).
Amd then tries to mount the file system you want to access.  After the
mount succeeds, amd sends a message back to the kernel.  My theory is that
while the kernel is waiting for the reply of the nfs server (that is, amd)
you cannot mount any NFS file systems.  If this is indeed the case, it is
impossible to get an automounter to work on Concentrix 5.5.02.

Any thoughts on this from anyone?  Alliant?
--
Sjoerd Mullender		Center for Mathematics and Computer Science
sjoerd@cwi.nl			Amsterdam, Netherlands