xref: /freebsd-10.0-release/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/taskq.h>
#include <sys/vnode.h>

/* Extensible attribute (xva) routines. */

/*
 * Zero out the structure, set the size of the requested/returned bitmaps,
 * set AT_XVATTR in the embedded vattr_t's va_mask, and set up the pointer
 * to the returned attributes array.
 */
void
xva_init(xvattr_t *xvap)
{
	bzero(xvap, sizeof (xvattr_t));
	xvap->xva_mapsize = XVA_MAPSIZE;
	xvap->xva_magic = XVA_MAGIC;
	xvap->xva_vattr.va_mask = AT_XVATTR;
	xvap->xva_rtnattrmapp = &(xvap->xva_rtnattrmap)[0];
}

/*
 * If AT_XVATTR is set, returns a pointer to the embedded xoptattr_t
 * structure.  Otherwise, returns NULL.
 */
xoptattr_t *
xva_getxoptattr(xvattr_t *xvap)
{
	xoptattr_t *xoap = NULL;
	if (xvap->xva_vattr.va_mask & AT_XVATTR)
		xoap = &xvap->xva_xoptattrs;
	return (xoap);
}

static void
vn_rele_inactive(vnode_t *vp)
{
	vrele(vp);
}

/*
 * Like vn_rele() except if we are going to call VOP_INACTIVE() then do it
 * asynchronously using a taskq. This can avoid deadlocks caused by re-entering
 * the file system as a result of releasing the vnode. Note, file systems
 * already have to handle the race where the vnode is incremented before the
 * inactive routine is called and does its locking.
 *
 * Warning: Excessive use of this routine can lead to performance problems.
 * This is because taskqs throttle back allocation if too many are created.
 */
void
vn_rele_async(vnode_t *vp, taskq_t *taskq)
{
	VERIFY(vp->v_count > 0);
	VI_LOCK(vp);
	if (vp->v_count == 1 && !(vp->v_iflag & VI_DOINGINACT)) {
		VI_UNLOCK(vp);
		VERIFY(taskq_dispatch((taskq_t *)taskq,
		    (task_func_t *)vn_rele_inactive, vp, TQ_SLEEP) != 0);
		return;
	}
	vp->v_usecount--;
	vdropl(vp);
}