/* $NetBSD: layer_subr.c,v 1.39 2022/04/10 09:50:46 andvar Exp $ */ /* * Copyright (c) 1999 National Aeronautics & Space Administration * All rights reserved. * * This software was written by William Studenmund of the * Numerical Aerospace Simulation Facility, NASA Ames Research Center. * * 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. Neither the name of the National Aeronautics & Space Administration * 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 NATIONAL AERONAUTICS & SPACE ADMINISTRATION * ``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 ADMINISTRATION OR CONTRIB- * UTORS 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. */ /* * 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. 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. * * from: Id: lofs_subr.c,v 1.11 1992/05/30 10:05:43 jsp Exp * @(#)null_subr.c 8.7 (Berkeley) 5/14/95 */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: layer_subr.c,v 1.39 2022/04/10 09:50:46 andvar Exp $"); #include <sys/param.h> #include <sys/systm.h> #include <sys/proc.h> #include <sys/time.h> #include <sys/vnode.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/kmem.h> #include <miscfs/genfs/layer.h> #include <miscfs/genfs/layer_extern.h> #ifdef LAYERFS_DIAGNOSTIC int layerfs_debug = 1; #endif /* * 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 VREF'd. When the * alias is removed the lower vnode is vrele'd. */ void layerfs_init(void) { /* Nothing. */ } void layerfs_done(void) { /* Nothing. */ } /* * layer_node_create: try to find an existing layerfs vnode referring to it, * otherwise make a new vnode which contains a reference to the lower vnode. */ int layer_node_create(struct mount *mp, struct vnode *lowervp, struct vnode **nvpp) { int error; struct vnode *aliasvp; error = vcache_get(mp, &lowervp, sizeof(lowervp), &aliasvp); if (error) return error; /* * Now that we acquired a reference on the upper vnode, release one * on the lower node. The existence of the layer_node retains one * reference to the lower node. */ vrele(lowervp); KASSERT(vrefcnt(lowervp) > 0); #ifdef LAYERFS_DIAGNOSTIC if (layerfs_debug) vprint("layer_node_create: alias", aliasvp); #endif *nvpp = aliasvp; return 0; } #ifdef LAYERFS_DIAGNOSTIC struct vnode * layer_checkvp(struct vnode *vp, const char *fil, int lno) { struct layer_node *a = VTOLAYER(vp); #ifdef notyet /* * Can't do this check because vop_reclaim runs * with a funny vop vector. * * WRS - no it doesnt... */ if (vp->v_op != layer_vnodeop_p) { printf ("layer_checkvp: on non-layer-node\n"); #ifdef notyet while (layer_checkvp_barrier) /*WAIT*/ ; #endif panic("layer_checkvp"); }; #endif if (a->layer_lowervp == NULL) { /* Should never happen */ int i; u_long *p; printf("vp = %p, ZERO ptr\n", vp); for (p = (u_long *) a, i = 0; i < 8; i++) printf(" %lx", p[i]); printf("\n"); /* wait for debugger */ panic("layer_checkvp"); } if (vrefcnt(a->layer_lowervp) < 1) { int i; u_long *p; printf("vp = %p, unref'ed lowervp\n", vp); for (p = (u_long *) a, i = 0; i < 8; i++) printf(" %lx", p[i]); printf("\n"); /* wait for debugger */ panic ("layer with unref'ed lowervp"); }; #ifdef notnow printf("layer %p/%d -> %p/%d [%s, %d]\n", LAYERTOV(a), vrefcnt(LAYERTOV(a)), a->layer_lowervp, vrefcnt(a->layer_lowervp), fil, lno); #endif return a->layer_lowervp; } #endif
