path: root/fs/afs/vnode.c

/* AFS vnode management
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include "internal.h"

#if 0
static noinline bool dump_tree_aux(struct rb_node *node, struct rb_node *parent,
				   int depth, char lr)
{
	struct afs_vnode *vnode;
	bool bad = false;

	if (!node)
		return false;

	if (node->rb_left)
		bad = dump_tree_aux(node->rb_left, node, depth + 2, '/');

	vnode = rb_entry(node, struct afs_vnode, cb_promise);
	_debug("%c %*.*s%c%p {%d}",
	       rb_is_red(node) ? 'R' : 'B',
	       depth, depth, "", lr,
	       vnode, vnode->cb_expires_at);
	if (rb_parent(node) != parent) {
		printk("BAD: %p != %p\n", rb_parent(node), parent);
		bad = true;
	}

	if (node->rb_right)
		bad |= dump_tree_aux(node->rb_right, node, depth + 2, '\\');

	return bad;
}

static noinline void dump_tree(const char *name, struct afs_server *server)
{
	_enter("%s", name);
	if (dump_tree_aux(server->cb_promises.rb_node, NULL, 0, '-'))
		BUG();
}
#endif

/*
 * insert a vnode into the backing server's vnode tree
 */
static void afs_install_vnode(struct afs_vnode *vnode,
			      struct afs_server *server)
{
	struct afs_server *old_server = vnode->server;
	struct afs_vnode *xvnode;
	struct rb_node *parent, **p;

	_enter("%p,%p", vnode, server);

	if (old_server) {
		spin_lock(&old_server->fs_lock);
		rb_erase(&vnode->server_rb, &old_server->fs_vnodes);
		spin_unlock(&old_server->fs_lock);
	}

	afs_get_server(server);
	vnode->server = server;
	afs_put_server(old_server);

	/* insert into the server's vnode tree in FID order */
	spin_lock(&server->fs_lock);

	parent = NULL;
	p = &server->fs_vnodes.rb_node;
	while (*p) {
		parent = *p;
		xvnode = rb_entry(parent, struct afs_vnode, server_rb);
		if (vnode->fid.vid < xvnode->fid.vid)
			p = &(*p)->rb_left;
		else if (vnode->fid.vid > xvnode->fid.vid)
			p = &(*p)->rb_right;
		else if (vnode->fid.vnode < xvnode->fid.vnode)
			p = &(*p)->rb_left;
		else if (vnode->fid.vnode > xvnode->fid.vnode)
			p = &(*p)->rb_right;
		else if (vnode->fid.unique < xvnode->fid.unique)
			p = &(*p)->rb_left;
		else if (vnode->fid.unique > xvnode->fid.unique)
			p = &(*p)->rb_right;
		else
			BUG(); /* can't happen unless afs_iget() malfunctions */
	}

	rb_link_node(&vnode->server_rb, parent, p);
	rb_insert_color(&vnode->server_rb, &server->fs_vnodes);

	spin_unlock(&server->fs_lock);
	_leave("");
}

/*
 * insert a vnode into the promising server's update/expiration tree
 * - caller must hold vnode->lock
 */
static void afs_vnode_note_promise(struct afs_vnode *vnode,
				   struct afs_server *server)
{
	struct afs_server *old_server;
	struct afs_vnode *xvnode;
	struct rb_node *parent, **p;

	_enter("%p,%p", vnode, server);

	ASSERT(server != NULL);

	old_server = vnode->server;
	if (vnode->cb_promised) {
		if (server == old_server &&
		    vnode->cb_expires == vnode->cb_expires_at) {
			_leave(" [no change]");
			return;
		}

		spin_lock(&old_server->cb_lock);
		if (vnode->cb_promised) {
			_debug("delete");
			rb_erase(&vnode->cb_promise, &old_server->cb_promises);
			vnode->cb_promised = false;
		}
		spin_unlock(&old_server->cb_lock);
	}

	if (vnode->server != server)
		afs_install_vnode(vnode, server);

	vnode->cb_expires_at = vnode->cb_expires;
	_debug("PROMISE on %p {%lu}",
	       vnode, (unsigned long) vnode->cb_expires_at);

	/* abuse an RB-tree to hold the expiration order (we may have multiple
	 * items with the same expiration time) */
	spin_lock(&server->cb_lock);

	parent = NULL;
	p = &server->cb_promises.rb_node;
	while (*p) {
		parent