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Diffstat (limited to 'sys/miscfs/nullfs/null_vnops.c')
-rw-r--r-- | sys/miscfs/nullfs/null_vnops.c | 852 |
1 files changed, 0 insertions, 852 deletions
diff --git a/sys/miscfs/nullfs/null_vnops.c b/sys/miscfs/nullfs/null_vnops.c deleted file mode 100644 index d37ef73..0000000 --- a/sys/miscfs/nullfs/null_vnops.c +++ /dev/null @@ -1,852 +0,0 @@ -/* - * Copyright (c) 1992, 1993 - * The Regents of the University of California. All rights reserved. - * - * This code is derived from software contributed to Berkeley by - * John Heidemann of the UCLA Ficus project. - * - * 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_vnops.c 8.6 (Berkeley) 5/27/95 - * - * Ancestors: - * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92 - * ...and... - * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project - * - * $FreeBSD$ - */ - -/* - * Null Layer - * - * (See mount_null(8) for more information.) - * - * The null layer duplicates a portion of the file system - * name space under a new name. In this respect, it is - * similar to the loopback file system. It differs from - * the loopback fs in two respects: it is implemented using - * a stackable layers techniques, and its "null-node"s stack above - * all lower-layer vnodes, not just over directory vnodes. - * - * The null layer has two purposes. First, it serves as a demonstration - * of layering by proving a layer which does nothing. (It actually - * does everything the loopback file system does, which is slightly - * more than nothing.) Second, the null layer can serve as a prototype - * layer. Since it provides all necessary layer framework, - * new file system layers can be created very easily be starting - * with a null layer. - * - * The remainder of this man page examines the null layer as a basis - * for constructing new layers. - * - * - * INSTANTIATING NEW NULL LAYERS - * - * New null layers are created with mount_null(8). - * Mount_null(8) takes two arguments, the pathname - * of the lower vfs (target-pn) and the pathname where the null - * layer will appear in the namespace (alias-pn). After - * the null layer is put into place, the contents - * of target-pn subtree will be aliased under alias-pn. - * - * - * OPERATION OF A NULL LAYER - * - * The null layer is the minimum file system layer, - * simply bypassing all possible operations to the lower layer - * for processing there. The majority of its activity centers - * on the bypass routine, through which nearly all vnode operations - * pass. - * - * The bypass routine accepts arbitrary vnode operations for - * handling by the lower layer. It begins by examing vnode - * operation arguments and replacing any null-nodes by their - * lower-layer equivlants. It then invokes the operation - * on the lower layer. Finally, it replaces the null-nodes - * in the arguments and, if a vnode is return by the operation, - * stacks a null-node on top of the returned vnode. - * - * Although bypass handles most operations, vop_getattr, vop_lock, - * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not - * bypassed. Vop_getattr must change the fsid being returned. - * Vop_lock and vop_unlock must handle any locking for the - * current vnode as well as pass the lock request down. - * Vop_inactive and vop_reclaim are not bypassed so that - * they can handle freeing null-layer specific data. Vop_print - * is not bypassed to avoid excessive debugging information. - * Also, certain vnode operations change the locking state within - * the operation (create, mknod, remove, link, rename, mkdir, rmdir, - * and symlink). Ideally these operations should not change the - * lock state, but should be changed to let the caller of the - * function unlock them. Otherwise all intermediate vnode layers - * (such as union, umapfs, etc) must catch these functions to do - * the necessary locking at their layer. - * - * - * INSTANTIATING VNODE STACKS - * - * Mounting associates the null layer with a lower layer, - * effect stacking two VFSes. Vnode stacks are instead - * created on demand as files are accessed. - * - * The initial mount creates a single vnode stack for the - * root of the new null layer. All other vnode stacks - * are created as a result of vnode operations on - * this or other null vnode stacks. - * - * New vnode stacks come into existance as a result of - * an operation which returns a vnode. - * The bypass routine stacks a null-node above the new - * vnode before returning it to the caller. - * - * For example, imagine mounting a null layer with - * "mount_null /usr/include /dev/layer/null". - * Changing directory to /dev/layer/null will assign - * the root null-node (which was created when the null layer was mounted). - * Now consider opening "sys". A vop_lookup would be - * done on the root null-node. This operation would bypass through - * to the lower layer which would return a vnode representing - * the UFS "sys". Null_bypass then builds a null-node - * aliasing the UFS "sys" and returns this to the caller. - * Later operations on the null-node "sys" will repeat this - * process when constructing other vnode stacks. - * - * - * CREATING OTHER FILE SYSTEM LAYERS - * - * One of the easiest ways to construct new file system layers is to make - * a copy of the null layer, rename all files and variables, and - * then begin modifing the copy. Sed can be used to easily rename - * all variables. - * - * The umap layer is an example of a layer descended from the - * null layer. - * - * - * INVOKING OPERATIONS ON LOWER LAYERS - * - * There are two techniques to invoke operations on a lower layer - * when the operation cannot be completely bypassed. Each method - * is appropriate in different situations. In both cases, - * it is the responsibility of the aliasing layer to make - * the operation arguments "correct" for the lower layer - * by mapping an vnode arguments to the lower layer. - * - * The first approach is to call the aliasing layer's bypass routine. - * This method is most suitable when you wish to invoke the operation - * currently being handled on the lower layer. It has the advantage - * that the bypass routine already must do argument mapping. - * An example of this is null_getattrs in the null layer. - * - * A second approach is to directly invoke vnode operations on - * the lower layer with the VOP_OPERATIONNAME interface. - * The advantage of this method is that it is easy to invoke - * arbitrary operations on the lower layer. The disadvantage - * is that vnode arguments must be manualy mapped. - * - */ - -#include <sys/param.h> -#include <sys/systm.h> -#include <sys/conf.h> -#include <sys/kernel.h> -#include <sys/lock.h> -#include <sys/malloc.h> -#include <sys/mount.h> -#include <sys/mutex.h> -#include <sys/namei.h> -#include <sys/sysctl.h> -#include <sys/vnode.h> - -#include <miscfs/nullfs/null.h> - -#include <vm/vm.h> -#include <vm/vm_extern.h> -#include <vm/vm_object.h> -#include <vm/vnode_pager.h> - -static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */ -SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW, - &null_bug_bypass, 0, ""); - -static int null_access(struct vop_access_args *ap); -static int null_createvobject(struct vop_createvobject_args *ap); -static int null_destroyvobject(struct vop_destroyvobject_args *ap); -static int null_getattr(struct vop_getattr_args *ap); -static int null_getvobject(struct vop_getvobject_args *ap); -static int null_inactive(struct vop_inactive_args *ap); -static int null_islocked(struct vop_islocked_args *ap); -static int null_lock(struct vop_lock_args *ap); -static int null_lookup(struct vop_lookup_args *ap); -static int null_open(struct vop_open_args *ap); -static int null_print(struct vop_print_args *ap); -static int null_reclaim(struct vop_reclaim_args *ap); -static int null_rename(struct vop_rename_args *ap); -static int null_setattr(struct vop_setattr_args *ap); -static int null_unlock(struct vop_unlock_args *ap); - -/* - * This is the 10-Apr-92 bypass routine. - * This version has been optimized for speed, throwing away some - * safety checks. It should still always work, but it's not as - * robust to programmer errors. - * - * In general, we map all vnodes going down and unmap them on the way back. - * As an exception to this, vnodes can be marked "unmapped" by setting - * the Nth bit in operation's vdesc_flags. - * - * Also, some BSD vnode operations have the side effect of vrele'ing - * their arguments. With stacking, the reference counts are held - * by the upper node, not the lower one, so we must handle these - * side-effects here. This is not of concern in Sun-derived systems - * since there are no such side-effects. - * - * This makes the following assumptions: - * - only one returned vpp - * - no INOUT vpp's (Sun's vop_open has one of these) - * - the vnode operation vector of the first vnode should be used - * to determine what implementation of the op should be invoked - * - all mapped vnodes are of our vnode-type (NEEDSWORK: - * problems on rmdir'ing mount points and renaming?) - */ -int -null_bypass(ap) - struct vop_generic_args /* { - struct vnodeop_desc *a_desc; - <other random data follows, presumably> - } */ *ap; -{ - register struct vnode **this_vp_p; - int error; - struct vnode *old_vps[VDESC_MAX_VPS]; - struct vnode **vps_p[VDESC_MAX_VPS]; - struct vnode ***vppp; - struct vnodeop_desc *descp = ap->a_desc; - int reles, i; - - if (null_bug_bypass) - printf ("null_bypass: %s\n", descp->vdesc_name); - -#ifdef DIAGNOSTIC - /* - * We require at least one vp. - */ - if (descp->vdesc_vp_offsets == NULL || - descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET) - panic ("null_bypass: no vp's in map"); -#endif - - /* - * Map the vnodes going in. - * Later, we'll invoke the operation based on - * the first mapped vnode's operation vector. - */ - reles = descp->vdesc_flags; - for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { - if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) - break; /* bail out at end of list */ - vps_p[i] = this_vp_p = - VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap); - /* - * We're not guaranteed that any but the first vnode - * are of our type. Check for and don't map any - * that aren't. (We must always map first vp or vclean fails.) - */ - if (i && (*this_vp_p == NULLVP || - (*this_vp_p)->v_op != null_vnodeop_p)) { - old_vps[i] = NULLVP; - } else { - old_vps[i] = *this_vp_p; - *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p); - /* - * XXX - Several operations have the side effect - * of vrele'ing their vp's. We must account for - * that. (This should go away in the future.) - */ - if (reles & VDESC_VP0_WILLRELE) - VREF(*this_vp_p); - } - - } - - /* - * Call the operation on the lower layer - * with the modified argument structure. - */ - if (vps_p[0] && *vps_p[0]) - error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap); - else { - printf("null_bypass: no map for %s\n", descp->vdesc_name); - error = EINVAL; - } - - /* - * Maintain the illusion of call-by-value - * by restoring vnodes in the argument structure - * to their original value. - */ - reles = descp->vdesc_flags; - for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { - if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) - break; /* bail out at end of list */ - if (old_vps[i]) { - *(vps_p[i]) = old_vps[i]; -#if 0 - if (reles & VDESC_VP0_WILLUNLOCK) - VOP_UNLOCK(*(vps_p[i]), LK_THISLAYER, curproc); -#endif - if (reles & VDESC_VP0_WILLRELE) - vrele(*(vps_p[i])); - } - } - - /* - * Map the possible out-going vpp - * (Assumes that the lower layer always returns - * a VREF'ed vpp unless it gets an error.) - */ - if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET && - !(descp->vdesc_flags & VDESC_NOMAP_VPP) && - !error) { - /* - * XXX - even though some ops have vpp returned vp's, - * several ops actually vrele this before returning. - * We must avoid these ops. - * (This should go away when these ops are regularized.) - */ - if (descp->vdesc_flags & VDESC_VPP_WILLRELE) - goto out; - vppp = VOPARG_OFFSETTO(struct vnode***, - descp->vdesc_vpp_offset,ap); - if (*vppp) - error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp); - } - - out: - return (error); -} - -/* - * We have to carry on the locking protocol on the null layer vnodes - * as we progress through the tree. We also have to enforce read-only - * if this layer is mounted read-only. - */ -static int -null_lookup(ap) - struct vop_lookup_args /* { - struct vnode * a_dvp; - struct vnode ** a_vpp; - struct componentname * a_cnp; - } */ *ap; -{ - struct componentname *cnp = ap->a_cnp; - struct vnode *dvp = ap->a_dvp; - struct proc *p = cnp->cn_proc; - int flags = cnp->cn_flags; - struct vnode *vp, *ldvp, *lvp; - int error; - - if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && - (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) - return (EROFS); - /* - * Although it is possible to call null_bypass(), we'll do - * a direct call to reduce overhead - */ - ldvp = NULLVPTOLOWERVP(dvp); - vp = lvp = NULL; - error = VOP_LOOKUP(ldvp, &lvp, cnp); - if (error == EJUSTRETURN && (flags & ISLASTCN) && - (dvp->v_mount->mnt_flag & MNT_RDONLY) && - (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) - error = EROFS; - - /* - * Rely only on the PDIRUNLOCK flag which should be carefully - * tracked by underlying filesystem. - */ - if (cnp->cn_flags & PDIRUNLOCK) - VOP_UNLOCK(dvp, LK_THISLAYER, p); - if ((error == 0 || error == EJUSTRETURN) && lvp != NULL) { - if (ldvp == lvp) { - *ap->a_vpp = dvp; - VREF(dvp); - vrele(lvp); - } else { - error = null_node_create(dvp->v_mount, lvp, &vp); - if (error == 0) - *ap->a_vpp = vp; - } - } - return (error); -} - -/* - * Setattr call. Disallow write attempts if the layer is mounted read-only. - */ -int -null_setattr(ap) - struct vop_setattr_args /* { - struct vnodeop_desc *a_desc; - struct vnode *a_vp; - struct vattr *a_vap; - struct ucred *a_cred; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - struct vattr *vap = ap->a_vap; - - if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || - vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || - vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && - (vp->v_mount->mnt_flag & MNT_RDONLY)) - return (EROFS); - if (vap->va_size != VNOVAL) { - switch (vp->v_type) { - case VDIR: - return (EISDIR); - case VCHR: - case VBLK: - case VSOCK: - case VFIFO: - if (vap->va_flags != VNOVAL) - return (EOPNOTSUPP); - return (0); - case VREG: - case VLNK: - default: - /* - * Disallow write attempts if the filesystem is - * mounted read-only. - */ - if (vp->v_mount->mnt_flag & MNT_RDONLY) - return (EROFS); - } - } - - return (null_bypass((struct vop_generic_args *)ap)); -} - -/* - * We handle getattr only to change the fsid. - */ -static int -null_getattr(ap) - struct vop_getattr_args /* { - struct vnode *a_vp; - struct vattr *a_vap; - struct ucred *a_cred; - struct proc *a_p; - } */ *ap; -{ - int error; - - if ((error = null_bypass((struct vop_generic_args *)ap)) != 0) - return (error); - - ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; - return (0); -} - -/* - * Handle to disallow write access if mounted read-only. - */ -static int -null_access(ap) - struct vop_access_args /* { - struct vnode *a_vp; - int a_mode; - struct ucred *a_cred; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - mode_t mode = ap->a_mode; - - /* - * Disallow write attempts on read-only layers; - * unless the file is a socket, fifo, or a block or - * character device resident on the file system. - */ - if (mode & VWRITE) { - switch (vp->v_type) { - case VDIR: - case VLNK: - case VREG: - if (vp->v_mount->mnt_flag & MNT_RDONLY) - return (EROFS); - break; - default: - break; - } - } - return (null_bypass((struct vop_generic_args *)ap)); -} - -/* - * We must handle open to be able to catch MNT_NODEV and friends. - */ -static int -null_open(ap) - struct vop_open_args /* { - struct vnode *a_vp; - int a_mode; - struct ucred *a_cred; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - struct vnode *lvp = NULLVPTOLOWERVP(ap->a_vp); - - if ((vp->v_mount->mnt_flag & MNT_NODEV) && - (lvp->v_type == VBLK || lvp->v_type == VCHR)) - return ENXIO; - - return (null_bypass((struct vop_generic_args *)ap)); -} - -/* - * We handle this to eliminate null FS to lower FS - * file moving. Don't know why we don't allow this, - * possibly we should. - */ -static int -null_rename(ap) - struct vop_rename_args /* { - struct vnode *a_fdvp; - struct vnode *a_fvp; - struct componentname *a_fcnp; - struct vnode *a_tdvp; - struct vnode *a_tvp; - struct componentname *a_tcnp; - } */ *ap; -{ - struct vnode *tdvp = ap->a_tdvp; - struct vnode *fvp = ap->a_fvp; - struct vnode *fdvp = ap->a_fdvp; - struct vnode *tvp = ap->a_tvp; - - /* Check for cross-device rename. */ - if ((fvp->v_mount != tdvp->v_mount) || - (tvp && (fvp->v_mount != tvp->v_mount))) { - if (tdvp == tvp) - vrele(tdvp); - else - vput(tdvp); - if (tvp) - vput(tvp); - vrele(fdvp); - vrele(fvp); - return (EXDEV); - } - - return (null_bypass((struct vop_generic_args *)ap)); -} - -/* - * We need to process our own vnode lock and then clear the - * interlock flag as it applies only to our vnode, not the - * vnodes below us on the stack. - */ -static int -null_lock(ap) - struct vop_lock_args /* { - struct vnode *a_vp; - int a_flags; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - int flags = ap->a_flags; - struct proc *p = ap->a_p; - struct vnode *lvp; - int error; - - if (flags & LK_THISLAYER) { - if (vp->v_vnlock != NULL) - return 0; /* lock is shared across layers */ - error = lockmgr(&vp->v_lock, flags & ~LK_THISLAYER, - &vp->v_interlock, p); - return (error); - } - - if (vp->v_vnlock != NULL) { - /* - * The lower level has exported a struct lock to us. Use - * it so that all vnodes in the stack lock and unlock - * simultaneously. Note: we don't DRAIN the lock as DRAIN - * decommissions the lock - just because our vnode is - * going away doesn't mean the struct lock below us is. - * LK_EXCLUSIVE is fine. - */ - if ((flags & LK_TYPE_MASK) == LK_DRAIN) { - NULLFSDEBUG("null_lock: avoiding LK_DRAIN\n"); - return(lockmgr(vp->v_vnlock, - (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE, - &vp->v_interlock, p)); - } - return(lockmgr(vp->v_vnlock, flags, &vp->v_interlock, p)); - } else { - /* - * To prevent race conditions involving doing a lookup - * on "..", we have to lock the lower node, then lock our - * node. Most of the time it won't matter that we lock our - * node (as any locking would need the lower one locked - * first). But we can LK_DRAIN the upper lock as a step - * towards decomissioning it. - */ - lvp = NULLVPTOLOWERVP(vp); - if (lvp == NULL) - return (lockmgr(&vp->v_lock, flags, &vp->v_interlock, p)); - if (flags & LK_INTERLOCK) { - mtx_unlock(&vp->v_interlock); - flags &= ~LK_INTERLOCK; - } - if ((flags & LK_TYPE_MASK) == LK_DRAIN) { - error = VOP_LOCK(lvp, - (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE, p); - } else - error = VOP_LOCK(lvp, flags, p); - if (error) - return (error); - error = lockmgr(&vp->v_lock, flags, &vp->v_interlock, p); - if (error) - VOP_UNLOCK(lvp, 0, p); - return (error); - } -} - -/* - * We need to process our own vnode unlock and then clear the - * interlock flag as it applies only to our vnode, not the - * vnodes below us on the stack. - */ -static int -null_unlock(ap) - struct vop_unlock_args /* { - struct vnode *a_vp; - int a_flags; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - int flags = ap->a_flags; - struct proc *p = ap->a_p; - struct vnode *lvp; - - if (vp->v_vnlock != NULL) { - if (flags & LK_THISLAYER) - return 0; /* the lock is shared across layers */ - flags &= ~LK_THISLAYER; - return (lockmgr(vp->v_vnlock, flags | LK_RELEASE, - &vp->v_interlock, p)); - } - lvp = NULLVPTOLOWERVP(vp); - if (lvp == NULL) - return (lockmgr(&vp->v_lock, flags | LK_RELEASE, &vp->v_interlock, p)); - if ((flags & LK_THISLAYER) == 0) { - if (flags & LK_INTERLOCK) { - mtx_unlock(&vp->v_interlock); - flags &= ~LK_INTERLOCK; - } - VOP_UNLOCK(lvp, flags & ~LK_INTERLOCK, p); - } else - flags &= ~LK_THISLAYER; - return (lockmgr(&vp->v_lock, flags | LK_RELEASE, &vp->v_interlock, p)); -} - -static int -null_islocked(ap) - struct vop_islocked_args /* { - struct vnode *a_vp; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - struct proc *p = ap->a_p; - - if (vp->v_vnlock != NULL) - return (lockstatus(vp->v_vnlock, p)); - return (lockstatus(&vp->v_lock, p)); -} - -/* - * There is no way to tell that someone issued remove/rmdir operation - * on the underlying filesystem. For now we just have to release lowevrp - * as soon as possible. - */ -static int -null_inactive(ap) - struct vop_inactive_args /* { - struct vnode *a_vp; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - struct proc *p = ap->a_p; - struct null_node *xp = VTONULL(vp); - struct vnode *lowervp = xp->null_lowervp; - - lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, p); - LIST_REMOVE(xp, null_hash); - lockmgr(&null_hashlock, LK_RELEASE, NULL, p); - - xp->null_lowervp = NULLVP; - if (vp->v_vnlock != NULL) { - vp->v_vnlock = &vp->v_lock; /* we no longer share the lock */ - } else - VOP_UNLOCK(vp, LK_THISLAYER, p); - - vput(lowervp); - /* - * Now it is safe to drop references to the lower vnode. - * VOP_INACTIVE() will be called by vrele() if necessary. - */ - vrele (lowervp); - - return (0); -} - -/* - * We can free memory in null_inactive, but we do this - * here. (Possible to guard vp->v_data to point somewhere) - */ -static int -null_reclaim(ap) - struct vop_reclaim_args /* { - struct vnode *a_vp; - struct proc *a_p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - void *vdata = vp->v_data; - - vp->v_data = NULL; - FREE(vdata, M_NULLFSNODE); - - return (0); -} - -static int -null_print(ap) - struct vop_print_args /* { - struct vnode *a_vp; - } */ *ap; -{ - register struct vnode *vp = ap->a_vp; - printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp)); - return (0); -} - -/* - * Let an underlying filesystem do the work - */ -static int -null_createvobject(ap) - struct vop_createvobject_args /* { - struct vnode *vp; - struct ucred *cred; - struct proc *p; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - struct vnode *lowervp = VTONULL(vp) ? NULLVPTOLOWERVP(vp) : NULL; - int error; - - if (vp->v_type == VNON || lowervp == NULL) - return 0; - error = VOP_CREATEVOBJECT(lowervp, ap->a_cred, ap->a_p); - if (error) - return (error); - vp->v_flag |= VOBJBUF; - return (0); -} - -/* - * We have nothing to destroy and this operation shouldn't be bypassed. - */ -static int -null_destroyvobject(ap) - struct vop_destroyvobject_args /* { - struct vnode *vp; - } */ *ap; -{ - struct vnode *vp = ap->a_vp; - - vp->v_flag &= ~VOBJBUF; - return (0); -} - -static int -null_getvobject(ap) - struct vop_getvobject_args /* { - struct vnode *vp; - struct vm_object **objpp; - } */ *ap; -{ - struct vnode *lvp = NULLVPTOLOWERVP(ap->a_vp); - - if (lvp == NULL) - return EINVAL; - return (VOP_GETVOBJECT(lvp, ap->a_objpp)); -} - -/* - * Global vfs data structures - */ -vop_t **null_vnodeop_p; -static struct vnodeopv_entry_desc null_vnodeop_entries[] = { - { &vop_default_desc, (vop_t *) null_bypass }, - - { &vop_access_desc, (vop_t *) null_access }, - { &vop_bmap_desc, (vop_t *) vop_eopnotsupp }, - { &vop_createvobject_desc, (vop_t *) null_createvobject }, - { &vop_destroyvobject_desc, (vop_t *) null_destroyvobject }, - { &vop_getattr_desc, (vop_t *) null_getattr }, - { &vop_getvobject_desc, (vop_t *) null_getvobject }, - { &vop_getwritemount_desc, (vop_t *) vop_stdgetwritemount}, - { &vop_inactive_desc, (vop_t *) null_inactive }, - { &vop_islocked_desc, (vop_t *) null_islocked }, - { &vop_lock_desc, (vop_t *) null_lock }, - { &vop_lookup_desc, (vop_t *) null_lookup }, - { &vop_open_desc, (vop_t *) null_open }, - { &vop_print_desc, (vop_t *) null_print }, - { &vop_reclaim_desc, (vop_t *) null_reclaim }, - { &vop_rename_desc, (vop_t *) null_rename }, - { &vop_setattr_desc, (vop_t *) null_setattr }, - { &vop_strategy_desc, (vop_t *) vop_eopnotsupp }, - { &vop_unlock_desc, (vop_t *) null_unlock }, - { NULL, NULL } -}; -static struct vnodeopv_desc null_vnodeop_opv_desc = - { &null_vnodeop_p, null_vnodeop_entries }; - -VNODEOP_SET(null_vnodeop_opv_desc); |