-/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. The rights granted to you under the License
- * may not be used to create, or enable the creation or redistribution of,
- * unlawful or unlicensed copies of an Apple operating system, or to
- * circumvent, violate, or enable the circumvention or violation of, any
- * terms of an Apple operating system software license agreement.
- *
- * Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
- */
-/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
-/*
- * Copyright (c) 1992, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * This code is derived from software donated to Berkeley by
- * Jan-Simon Pendry.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * @(#)null_subr.c 8.7 (Berkeley) 5/14/95
- *
- * null_subr.c 8.4 (Berkeley) 1/21/94
- */
-
-#include <sys/param.h>
-#include <sys/systm.h>
-#include <sys/proc.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <sys/vnode.h>
-#include <sys/mount_internal.h>
-#include <sys/namei.h>
-#include <sys/malloc.h>
-#include <sys/ubc.h>
-#include <miscfs/nullfs/null.h>
-
-#define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
-#define NNULLNODECACHE 16
-
-/*
- * Null layer cache:
- * Each cache entry holds a reference to the lower vnode
- * along with a pointer to the alias vnode. When an
- * entry is added the lower vnode is vnode_get'd. When the
- * alias is removed the lower vnode is vnode_put'd.
- */
-
-#define NULL_NHASH(vp) \
- (&null_node_hashtbl[(((uintptr_t)vp)>>LOG2_SIZEVNODE) & null_node_hash])
-LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
-u_long null_node_hash;
-
-/*
- * Initialise cache headers
- */
-nullfs_init()
-{
-
-#ifdef NULLFS_DIAGNOSTIC
- printf("nullfs_init\n"); /* printed during system boot */
-#endif
- null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
-}
-
-/*
- * Return a vnode_get'ed alias for lower vnode if already exists, else 0.
- */
-static struct vnode *
-null_node_find(mp, lowervp)
- struct mount *mp;
- struct vnode *lowervp;
-{
- struct proc *p = curproc; /* XXX */
- struct null_node_hashhead *hd;
- struct null_node *a;
- struct vnode *vp;
-
- /*
- * Find hash base, and then search the (two-way) linked
- * list looking for a null_node structure which is referencing
- * the lower vnode. If found, the increment the null_node
- * reference count (but NOT the lower vnode's vnode_get counter).
- */
- hd = NULL_NHASH(lowervp);
-loop:
- for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
- if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
- vp = NULLTOV(a);
-
- if (vnode_get(vp)) {
- printf ("null_node_find: vget failed.\n");
- goto loop;
- };
- return (vp);
- }
- }
-
- return NULL;
-}
-
-
-/*
- * Make a new null_node node.
- * Vp is the alias vnode, lofsvp is the lower vnode.
- * Maintain a reference to (lowervp).
- */
-static int
-null_node_alloc(mp, lowervp, vpp)
- struct mount *mp;
- struct vnode *lowervp;
- struct vnode **vpp;
-{
- struct null_node_hashhead *hd;
- struct null_node *xp;
- struct vnode *othervp, *vp;
- int error;
-
- MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
- if (error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp)) {
- FREE(xp, M_TEMP);
- return (error);
- }
- vp = *vpp;
-
- vp->v_type = lowervp->v_type;
- xp->null_vnode = vp;
- vp->v_data = xp;
- xp->null_lowervp = lowervp;
- /*
- * Before we insert our new node onto the hash chains,
- * check to see if someone else has beaten us to it.
- */
- if (othervp = null_node_find(lowervp)) {
- FREE(xp, M_TEMP);
- vp->v_type = VBAD; /* node is discarded */
- vp->v_usecount = 0; /* XXX */
- vp->v_data = 0; /* prevent access to freed data */
- *vpp = othervp;
- return 0;
- };
- if (vp->v_type == VREG)
- ubc_info_init(vp);
- vnode_get(lowervp); /* Extra vnode_get will be vnode_put'd in null_node_create */
- hd = NULL_NHASH(lowervp);
- LIST_INSERT_HEAD(hd, xp, null_hash);
- return 0;
-}
-
-
-/*
- * Try to find an existing null_node vnode refering
- * to it, otherwise make a new null_node vnode which
- * contains a reference to the lower vnode.
- */
-int
-null_node_create(mp, lowervp, newvpp)
- struct mount *mp;
- struct vnode *lowervp;
- struct vnode **newvpp;
-{
- struct vnode *aliasvp;
-
- if (aliasvp = null_node_find(mp, lowervp)) {
- /*
- * null_node_find has taken another reference
- * to the alias vnode.
- */
-#ifdef NULLFS_DIAGNOSTIC
- vprint("null_node_create: exists", NULLTOV(ap));
-#endif
- /* vnode_get(aliasvp); --- done in null_node_find */
- } else {
- int error;
-
- /*
- * Get new vnode.
- */
-#ifdef NULLFS_DIAGNOSTIC
- printf("null_node_create: create new alias vnode\n");
-#endif
-
- /*
- * Make new vnode reference the null_node.
- */
- if (error = null_node_alloc(mp, lowervp, &aliasvp))
- return error;
-
- /*
- * aliasvp is already vnode_get'd by getnewvnode()
- */
- }
-
- vnode_put(lowervp);
-
-#if DIAGNOSTIC
- if (lowervp->v_usecount < 1) {
- /* Should never happen... */
- vprint ("null_node_create: alias ", aliasvp);
- vprint ("null_node_create: lower ", lowervp);
- panic ("null_node_create: lower has 0 usecount.");
- };
-#endif
-
-#ifdef NULLFS_DIAGNOSTIC
- vprint("null_node_create: alias", aliasvp);
- vprint("null_node_create: lower", lowervp);
-#endif
-
- *newvpp = aliasvp;
- return (0);
-}
-#ifdef NULLFS_DIAGNOSTIC
-struct vnode *
-null_checkvp(vp, fil, lno)
- struct vnode *vp;
- char *fil;
- int lno;
-{
- struct null_node *a = VTONULL(vp);
-#ifdef notyet
- /*
- * Can't do this check because vnop_reclaim runs
- * with a funny vop vector.
- */
- if (vp->v_op != null_vnodeop_p) {
- printf ("null_checkvp: on non-null-node\n");
- while (null_checkvp_barrier) /*WAIT*/ ;
- panic("null_checkvp");
- };
-#endif
- if (a->null_lowervp == NULL) {
- /* Should never happen */
- int i; uint32_t *p;
- printf("vp = %x, ZERO ptr\n", vp);
- for (p = (uint32_t *) a, i = 0; i < 8; i++)
- printf(" %x", p[i]);
- printf("\n");
- /* wait for debugger */
- while (null_checkvp_barrier) /*WAIT*/ ;
- panic("null_checkvp");
- }
- if (a->null_lowervp->v_usecount < 1) {
- int i; uint32_t *p;
- printf("vp = %x, unref'ed lowervp\n", vp);
- for (p = (uint32_t *) a, i = 0; i < 8; i++)
- printf(" %x", p[i]);
- printf("\n");
- /* wait for debugger */
- while (null_checkvp_barrier) /*WAIT*/ ;
- panic ("null with unref'ed lowervp");
- };
-#ifdef notyet
- printf("null %x/%d -> %x/%d [%s, %d]\n",
- NULLTOV(a), NULLTOV(a)->v_usecount,
- a->null_lowervp, a->null_lowervp->v_usecount,
- fil, lno);
-#endif
- return a->null_lowervp;
-}
-#endif
projects / apple / xnu.git / blobdiff