diff options
Diffstat (limited to 'sys/miscfs/nullfs/null_subr.c')
| -rw-r--r-- | sys/miscfs/nullfs/null_subr.c | 345 |
1 files changed, 0 insertions, 345 deletions
diff --git a/sys/miscfs/nullfs/null_subr.c b/sys/miscfs/nullfs/null_subr.c deleted file mode 100644 index 88f1584..0000000 --- a/sys/miscfs/nullfs/null_subr.c +++ /dev/null @@ -1,345 +0,0 @@ -/* - * 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 - * - * $FreeBSD$ - */ - -#include <sys/param.h> -#include <sys/systm.h> -#include <sys/kernel.h> -#include <sys/lock.h> -#include <sys/malloc.h> -#include <sys/mount.h> -#include <sys/proc.h> -#include <sys/vnode.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 VREF'd. When the - * alias is removed the lower vnode is vrele'd. - */ - -#define NULL_NHASH(vp) \ - (&null_node_hashtbl[(((uintptr_t)vp)>>LOG2_SIZEVNODE) & null_node_hash]) - -static LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl; -static u_long null_node_hash; -struct lock null_hashlock; - -static MALLOC_DEFINE(M_NULLFSHASH, "NULLFS hash", "NULLFS hash table"); -MALLOC_DEFINE(M_NULLFSNODE, "NULLFS node", "NULLFS vnode private part"); - -static int null_node_alloc(struct mount *mp, struct vnode *lowervp, - struct vnode **vpp); -static struct vnode * - null_node_find(struct mount *mp, struct vnode *lowervp); - -/* - * Initialise cache headers - */ -int -nullfs_init(vfsp) - struct vfsconf *vfsp; -{ - - NULLFSDEBUG("nullfs_init\n"); /* printed during system boot */ - null_node_hashtbl = hashinit(NNULLNODECACHE, M_NULLFSHASH, &null_node_hash); - lockinit(&null_hashlock, PVFS, "nullhs", 0, 0); - return (0); -} - -int -nullfs_uninit(vfsp) - struct vfsconf *vfsp; -{ - - if (null_node_hashtbl) { - lockdestroy(&null_hashlock); - free(null_node_hashtbl, M_NULLFSHASH); - } - return (0); -} - -/* - * Return a VREF'ed alias for lower vnode if already exists, else 0. - * Lower vnode should be locked on entry and will be left locked on exit. - */ -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 VREF counter). - */ - hd = NULL_NHASH(lowervp); -loop: - lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, p); - LIST_FOREACH(a, hd, null_hash) { - if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) { - vp = NULLTOV(a); - lockmgr(&null_hashlock, LK_RELEASE, NULL, p); - /* - * We need vget for the VXLOCK - * stuff, but we don't want to lock - * the lower node. - */ - if (vget(vp, LK_EXCLUSIVE | LK_CANRECURSE, p)) { - printf ("null_node_find: vget failed.\n"); - goto loop; - }; - /* - * Now we got both vnodes locked, so release the - * lower one. - */ - VOP_UNLOCK(lowervp, 0, p); - return (vp); - } - } - lockmgr(&null_hashlock, LK_RELEASE, NULL, p); - - return NULLVP; -} - - -/* - * 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 proc *p = curproc; /* XXX */ - struct null_node_hashhead *hd; - struct null_node *xp; - struct vnode *othervp, *vp; - int error; - - /* - * Do the MALLOC before the getnewvnode since doing so afterward - * might cause a bogus v_data pointer to get dereferenced - * elsewhere if MALLOC should block. - */ - MALLOC(xp, struct null_node *, sizeof(struct null_node), - M_NULLFSNODE, M_WAITOK); - - error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp); - if (error) { - FREE(xp, M_NULLFSNODE); - 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. - * (We could have slept in MALLOC.) - */ - othervp = null_node_find(mp, lowervp); - if (othervp) { - vp->v_data = NULL; - FREE(xp, M_NULLFSNODE); - vp->v_type = VBAD; /* node is discarded */ - vrele(vp); - *vpp = othervp; - return 0; - }; - - /* - * From NetBSD: - * Now lock the new node. We rely on the fact that we were passed - * a locked vnode. If the lower node is exporting a struct lock - * (v_vnlock != NULL) then we just set the upper v_vnlock to the - * lower one, and both are now locked. If the lower node is exporting - * NULL, then we copy that up and manually lock the new vnode. - */ - - lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, p); - vp->v_vnlock = lowervp->v_vnlock; - error = VOP_LOCK(vp, LK_EXCLUSIVE | LK_THISLAYER, p); - if (error) - panic("null_node_alloc: can't lock new vnode\n"); - - VREF(lowervp); - hd = NULL_NHASH(lowervp); - LIST_INSERT_HEAD(hd, xp, null_hash); - lockmgr(&null_hashlock, LK_RELEASE, NULL, p); - return 0; -} - - -/* - * Try to find an existing null_node vnode refering to the given underlying - * vnode (which should be locked). If no vnode found, create 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; - - aliasvp = null_node_find(mp, lowervp); - if (aliasvp) { - /* - * null_node_find has taken another reference - * to the alias vnode. - */ - vrele(lowervp); -#ifdef NULLFS_DEBUG - vprint("null_node_create: exists", aliasvp); -#endif - } else { - int error; - - /* - * Get new vnode. - */ - NULLFSDEBUG("null_node_create: create new alias vnode\n"); - - /* - * Make new vnode reference the null_node. - */ - error = null_node_alloc(mp, lowervp, &aliasvp); - if (error) - return error; - - /* - * aliasvp is already VREF'd by getnewvnode() - */ - } - -#ifdef 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_DEBUG - vprint("null_node_create: alias", aliasvp); - vprint("null_node_create: lower", lowervp); -#endif - - *newvpp = aliasvp; - return (0); -} - -#ifdef DIAGNOSTIC -#include "opt_ddb.h" - -#ifdef DDB -#define null_checkvp_barrier 1 -#else -#define null_checkvp_barrier 0 -#endif - -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 vop_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 == NULLVP) { - /* Should never happen */ - int i; u_long *p; - printf("vp = %p, ZERO ptr\n", (void *)vp); - for (p = (u_long *) a, i = 0; i < 8; i++) - printf(" %lx", p[i]); - printf("\n"); - /* wait for debugger */ - while (null_checkvp_barrier) /*WAIT*/ ; - panic("null_checkvp"); - } - if (a->null_lowervp->v_usecount < 1) { - int i; u_long *p; - printf("vp = %p, unref'ed lowervp\n", (void *)vp); - for (p = (u_long *) a, i = 0; i < 8; i++) - printf(" %lx", 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 |
