1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26/*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27/*	  All Rights Reserved  	*/
28
29/*
30 * University Copyright- Copyright (c) 1982, 1986, 1988
31 * The Regents of the University of California
32 * All Rights Reserved
33 *
34 * University Acknowledgment- Portions of this document are derived from
35 * software developed by the University of California, Berkeley, and its
36 * contributors.
37 */
38
39#include <sys/types.h>
40#include <sys/param.h>
41#include <sys/proc.h>
42#include <sys/taskq.h>
43#include <sys/vnode.h>
44
45/* Extensible attribute (xva) routines. */
46
47/*
48 * Zero out the structure, set the size of the requested/returned bitmaps,
49 * set AT_XVATTR in the embedded vattr_t's va_mask, and set up the pointer
50 * to the returned attributes array.
51 */
52void
53xva_init(xvattr_t *xvap)
54{
55	bzero(xvap, sizeof (xvattr_t));
56	xvap->xva_mapsize = XVA_MAPSIZE;
57	xvap->xva_magic = XVA_MAGIC;
58	xvap->xva_vattr.va_mask = AT_XVATTR;
59	xvap->xva_rtnattrmapp = &(xvap->xva_rtnattrmap)[0];
60}
61
62/*
63 * If AT_XVATTR is set, returns a pointer to the embedded xoptattr_t
64 * structure.  Otherwise, returns NULL.
65 */
66xoptattr_t *
67xva_getxoptattr(xvattr_t *xvap)
68{
69	xoptattr_t *xoap = NULL;
70	if (xvap->xva_vattr.va_mask & AT_XVATTR)
71		xoap = &xvap->xva_xoptattrs;
72	return (xoap);
73}
74
75/*
76 * Like vn_rele() except if we are going to call VOP_INACTIVE() then do it
77 * asynchronously using a taskq. This can avoid deadlocks caused by re-entering
78 * the file system as a result of releasing the vnode. Note, file systems
79 * already have to handle the race where the vnode is incremented before the
80 * inactive routine is called and does its locking.
81 *
82 * Warning: Excessive use of this routine can lead to performance problems.
83 * This is because taskqs throttle back allocation if too many are created.
84 */
85void
86vn_rele_async(vnode_t *vp, taskq_t *taskq)
87{
88	VERIFY(vp->v_count > 0);
89	if (refcount_release_if_not_last(&vp->v_usecount)) {
90		vdrop(vp);
91		return;
92	}
93	VERIFY(taskq_dispatch((taskq_t *)taskq,
94	    (task_func_t *)vrele, vp, TQ_SLEEP) != 0);
95}
96