Urgent help needed on an NFS question, please help!!!

From: Xin Zhao
Date: Thu Aug 10 2006 - 01:02:04 EST

I just ran into a problem about NFS. It might be a fundmental problem
of my current work. So please help!

I am wondering how NFS guarantees a client didn't get wrong file
attributes. Consider the following scenario:

Suppose we have an NFS server S and two clients C1 and C2.

Now C1 needs to access the file attributes of file X, it first does
lookup() to get the file handle of file X.

After C1 gets X's file handle and before C1 issues the getattr()
request, C2 cuts in. Now C2 deletes file X and creates a new file X1,
which has different name but the same inode number and device ID as
the nonexistent file X.

When C1 issues getattr() with the old file handle, it may get file
attribute on wrong file X1. Is this true?

If not, how NFS avoid this problem? Please direct me to the code that
verifies this.

Many many thanks!

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