vfs: push dentry_unhash on rmdir into file systems

Only a few file systems need this.  Start by pushing it down into each
fs rmdir method (except gfs2 and xfs) so it can be dealt with on a per-fs
basis.

This does not change behavior for any in-tree file systems.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 7f6c677..ecd7717 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -814,6 +814,7 @@
 
 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 {
+	dentry_unhash(d);
 	return v9fs_remove(i, d, 1);
 }