This bug has been copied from bug #582321 and has been proposed to be backported to 5.5 z-stream (EUS).
in 2.6.18-194.6.1.el5
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: When an NFS server exported a file system with an explicit "fsid=[file_system_ID]", an NFS client mounted that file system on one mount point and a subdirectory of that file system on a separate mount point, then if the server re-exported that file system after un-exporting and unmounting it, it was possible for the NFS client to unmount those mount points and receive the following error message: "VFS: Busy inodes after unmount..." Additionally, it was possible to crash the NFS client's kernel in this situation.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2010-0504.html