NFS: Avoid changing nlink when file removes and attribute updates race

NFS: Avoid changing nlink when file removes and attribute updates race

[ Upstream commit bd4928ec799b31c492eb63f9f4a0c1e0bb4bb3f7 ]

If a file removal races with another operation that updates its
attributes, then skip the change to nlink, and just mark the attributes
as being stale.

Reported-by: Aiden Lambert <alambert48@gatech.edu>
Fixes: 59a707b0d42e ("NFS: Ensure we revalidate the inode correctly after remove or rename")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>