[PATCH] fs/namei.c: Call to file_permission() under a spinlock in do_lookup_path()
We're presently running lock_kernel() under fs_lock via nfs's ->permission
handler. That's a ranking bug and sometimes a sleep-in-spinlock bug. This
problem was introduced in the openat() patchset.
We should not need to hold the current->fs->lock for a codepath that doesn't
use current->fs.