NFS client bug

[Alan Cox]

During some discussion with Al Viro about the right way to do supermount he
complained that it probably wanted doing in userspace. Anyway I was actually
annoyed enough with the magicdev program to try and do this.

I have it working for a subset of working (only one device, hardcoded path)
except for what seems to be an NFS client bug.

For obvious reasons I mount with very little caching in the client. 
[mount -oport=497,mountprog=200005,noac,nolock,soft
	127.0.0.1:/var/cache/volumagic/cdrom /mnt/cdrom]

Everything is fine until I do 

	cd /mnt/cdrom/somedir

[remove CD, insert different CD]

	ls

	[stale NFS file handle - correct so far]

[remove CD, insert original CD]

	ls

	[stale NFS file handle - cached on client - wrong]

It then gets more bizarre

	cd /mnt/cdrom/somedir

	[Looks ok a new filehandle, works ok]
	ls
	[Immediate stale NFS file handle from client - no traffic]

It seems this 'dead' handle remains stuck in the system until umount.

Alan