suse man page for __d_drop

__D_DROP(9)							   The Linux VFS						       __D_DROP(9)

NAME
       __d_drop - drop a dentry

SYNOPSIS
       void __d_drop(struct dentry * dentry);

ARGUMENTS
       dentry
	   dentry to drop

DESCRIPTION
       d_drop unhashes the entry from the parent dentry hashes, so that it won't be found through a VFS lookup any more. Note that this is
       different from deleting the dentry - d_delete will try to mark the dentry negative if possible, giving a successful _negative_ lookup,
       while d_drop will just make the cache lookup fail.

       d_drop is used mainly for stuff that wants to invalidate a dentry for some reason (NFS timeouts or autofs deletes).

       __d_drop requires dentry->d_lock.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010							       __D_DROP(9)