move the call of __d_drop(anon) into __d_materialise_unique(dentry, anon)

commit 6f18493e upstream.

and lock the right list there
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>

fs/dcache.c

@@ -2405,6 +2405,12 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
 	dentry->d_parent = dentry;
 	list_del_init(&dentry->d_child);
 	anon->d_parent = dparent;
+	if (likely(!d_unhashed(anon))) {
+		hlist_bl_lock(&anon->d_sb->s_anon);
+		__hlist_bl_del(&anon->d_hash);
+		anon->d_hash.pprev = NULL;
+		hlist_bl_unlock(&anon->d_sb->s_anon);
+	}
 	list_move(&anon->d_child, &dparent->d_subdirs);
 
 	write_seqcount_end(&dentry->d_seq);
@@ -2459,7 +2465,6 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 				 * could splice into our tree? */
 				__d_materialise_dentry(dentry, alias);
 				write_sequnlock(&rename_lock);
-				__d_drop(alias);
 				goto found;
 			} else {
 				/* Nope, but we must(!) avoid directory