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From: subbarao@phoenix.Princeton.EDU (Kartik Subbarao)
Newsgroups: comp.unix.shell
Subject: Re: NFS File identity resolution?
Message-ID: <7169@idunno.Princeton.EDU>
Date: 14 Mar 91 16:22:41 GMT
References: <21078@shlump.nac.dec.com>
Sender: news@idunno.Princeton.EDU
Lines: 29

In article <21078@shlump.nac.dec.com> prakash@aiag.enet.dec.com writes:
>--
>
>Given a set of NFS servers and clients on the same network, and two
>processes A and B on possibly different nodes, which can communicate
>using sockets. How can the two processes determine if a file referred to
>as "/a/b/c/file" by process A is really the file referred to as "/A/B/file"
>by the process B? In other words, on the node of the process A, "/a/c/b"
>could be mounted on X:/server/dir, and on the node of process B, "/A/B"
>could be mounted on X:/server/dir. It is therefore not enough to compare
>the directory parts alone. One must be able to determine which server
>the file is coming from. [Essentially what the define command does, but
>I want to do it from C].

You can stat() both files, and compare the inodes and see if they're the
same. This would only be a problem, I would guess, if the two files had the
exact same inode number but in fact came from two different disks. Of
course, you could do a simple popen() to df, chop out the right field, and 
make sure that they're the same. This would confirm that they were mounted
on the same place.

			-Kartik
		

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