2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * John Heidemann of the UCLA Ficus project.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
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17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95
39 * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92
40 * $FreeBSD: src/sys/miscfs/nullfs/null_vnops.c,v 1.38.2.6 2002/07/31 00:32:28 semenu Exp $
41 * $DragonFly: src/sys/vfs/nullfs/null_vnops.c,v 1.13 2004/08/17 18:57:34 dillon Exp $
43 * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
45 * $FreeBSD: src/sys/miscfs/nullfs/null_vnops.c,v 1.38.2.6 2002/07/31 00:32:28 semenu Exp $
51 * (See mount_null(8) for more information.)
53 * The null layer duplicates a portion of the file system
54 * name space under a new name. In this respect, it is
55 * similar to the loopback file system. It differs from
56 * the loopback fs in two respects: it is implemented using
57 * a stackable layers techniques, and its "null-node"s stack above
58 * all lower-layer vnodes, not just over directory vnodes.
60 * The null layer has two purposes. First, it serves as a demonstration
61 * of layering by proving a layer which does nothing. (It actually
62 * does everything the loopback file system does, which is slightly
63 * more than nothing.) Second, the null layer can serve as a prototype
64 * layer. Since it provides all necessary layer framework,
65 * new file system layers can be created very easily be starting
68 * The remainder of this man page examines the null layer as a basis
69 * for constructing new layers.
72 * INSTANTIATING NEW NULL LAYERS
74 * New null layers are created with mount_null(8).
75 * Mount_null(8) takes two arguments, the pathname
76 * of the lower vfs (target-pn) and the pathname where the null
77 * layer will appear in the namespace (alias-pn). After
78 * the null layer is put into place, the contents
79 * of target-pn subtree will be aliased under alias-pn.
82 * OPERATION OF A NULL LAYER
84 * The null layer is the minimum file system layer,
85 * simply bypassing all possible operations to the lower layer
86 * for processing there. The majority of its activity centers
87 * on the bypass routine, through which nearly all vnode operations
90 * The bypass routine accepts arbitrary vnode operations for
91 * handling by the lower layer. It begins by examing vnode
92 * operation arguments and replacing any null-nodes by their
93 * lower-layer equivlants. It then invokes the operation
94 * on the lower layer. Finally, it replaces the null-nodes
95 * in the arguments and, if a vnode is return by the operation,
96 * stacks a null-node on top of the returned vnode.
98 * Although bypass handles most operations, vop_getattr, vop_lock,
99 * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not
100 * bypassed. Vop_getattr must change the fsid being returned.
101 * Vop_lock and vop_unlock must handle any locking for the
102 * current vnode as well as pass the lock request down.
103 * Vop_inactive and vop_reclaim are not bypassed so that
104 * they can handle freeing null-layer specific data. Vop_print
105 * is not bypassed to avoid excessive debugging information.
106 * Also, certain vnode operations change the locking state within
107 * the operation (create, mknod, remove, link, rename, mkdir, rmdir,
108 * and symlink). Ideally these operations should not change the
109 * lock state, but should be changed to let the caller of the
110 * function unlock them. Otherwise all intermediate vnode layers
111 * (such as union, umapfs, etc) must catch these functions to do
112 * the necessary locking at their layer.
115 * INSTANTIATING VNODE STACKS
117 * Mounting associates the null layer with a lower layer,
118 * effect stacking two VFSes. Vnode stacks are instead
119 * created on demand as files are accessed.
121 * The initial mount creates a single vnode stack for the
122 * root of the new null layer. All other vnode stacks
123 * are created as a result of vnode operations on
124 * this or other null vnode stacks.
126 * New vnode stacks come into existance as a result of
127 * an operation which returns a vnode.
128 * The bypass routine stacks a null-node above the new
129 * vnode before returning it to the caller.
131 * For example, imagine mounting a null layer with
132 * "mount_null /usr/include /dev/layer/null".
133 * Changing directory to /dev/layer/null will assign
134 * the root null-node (which was created when the null layer was mounted).
135 * Now consider opening "sys". A vop_lookup would be
136 * done on the root null-node. This operation would bypass through
137 * to the lower layer which would return a vnode representing
138 * the UFS "sys". Null_bypass then builds a null-node
139 * aliasing the UFS "sys" and returns this to the caller.
140 * Later operations on the null-node "sys" will repeat this
141 * process when constructing other vnode stacks.
144 * CREATING OTHER FILE SYSTEM LAYERS
146 * One of the easiest ways to construct new file system layers is to make
147 * a copy of the null layer, rename all files and variables, and
148 * then begin modifing the copy. Sed can be used to easily rename
151 * The umap layer is an example of a layer descended from the
155 * INVOKING OPERATIONS ON LOWER LAYERS
157 * There are two techniques to invoke operations on a lower layer
158 * when the operation cannot be completely bypassed. Each method
159 * is appropriate in different situations. In both cases,
160 * it is the responsibility of the aliasing layer to make
161 * the operation arguments "correct" for the lower layer
162 * by mapping an vnode arguments to the lower layer.
164 * The first approach is to call the aliasing layer's bypass routine.
165 * This method is most suitable when you wish to invoke the operation
166 * currently being handled on the lower layer. It has the advantage
167 * that the bypass routine already must do argument mapping.
168 * An example of this is null_getattrs in the null layer.
170 * A second approach is to directly invoke vnode operations on
171 * the lower layer with the VOP_OPERATIONNAME interface.
172 * The advantage of this method is that it is easy to invoke
173 * arbitrary operations on the lower layer. The disadvantage
174 * is that vnode arguments must be manualy mapped.
178 #include <sys/param.h>
179 #include <sys/systm.h>
180 #include <sys/kernel.h>
181 #include <sys/sysctl.h>
182 #include <sys/vnode.h>
183 #include <sys/mount.h>
184 #include <sys/proc.h>
185 #include <sys/namei.h>
186 #include <sys/malloc.h>
190 static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */
191 SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW,
192 &null_bug_bypass, 0, "");
194 static int null_access(struct vop_access_args *ap);
195 static int null_createvobject(struct vop_createvobject_args *ap);
196 static int null_destroyvobject(struct vop_destroyvobject_args *ap);
197 static int null_getattr(struct vop_getattr_args *ap);
198 static int null_getvobject(struct vop_getvobject_args *ap);
199 static int null_inactive(struct vop_inactive_args *ap);
200 static int null_islocked(struct vop_islocked_args *ap);
201 static int null_lock(struct vop_lock_args *ap);
202 static int null_lookup(struct vop_lookup_args *ap);
203 static int null_open(struct vop_open_args *ap);
204 static int null_print(struct vop_print_args *ap);
205 static int null_reclaim(struct vop_reclaim_args *ap);
206 static int null_rename(struct vop_rename_args *ap);
207 static int null_setattr(struct vop_setattr_args *ap);
208 static int null_unlock(struct vop_unlock_args *ap);
211 * This is the 10-Apr-92 bypass routine.
212 * This version has been optimized for speed, throwing away some
213 * safety checks. It should still always work, but it's not as
214 * robust to programmer errors.
216 * In general, we map all vnodes going down and unmap them on the way back.
217 * As an exception to this, vnodes can be marked "unmapped" by setting
218 * the Nth bit in operation's vdesc_flags.
220 * Also, some BSD vnode operations have the side effect of vrele'ing
221 * their arguments. With stacking, the reference counts are held
222 * by the upper node, not the lower one, so we must handle these
223 * side-effects here. This is not of concern in Sun-derived systems
224 * since there are no such side-effects.
226 * This makes the following assumptions:
227 * - only one returned vpp
228 * - no INOUT vpp's (Sun's vop_open has one of these)
229 * - the vnode operation vector of the first vnode should be used
230 * to determine what implementation of the op should be invoked
231 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
232 * problems on rmdir'ing mount points and renaming?)
234 * null_bypass(struct vnodeop_desc *a_desc, ...)
237 null_bypass(struct vop_generic_args *ap)
239 register struct vnode **this_vp_p;
241 struct vnode *old_vps[VDESC_MAX_VPS];
242 struct vnode **vps_p[VDESC_MAX_VPS];
243 struct vnode ***vppp;
244 struct vnodeop_desc *descp = ap->a_desc;
248 printf ("null_bypass: %s\n", descp->vdesc_name);
252 * We require at least one vp.
254 if (descp->vdesc_vp_offsets == NULL ||
255 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
256 panic ("null_bypass: no vp's in map");
260 * Map the vnodes going in.
261 * Later, we'll invoke the operation based on
262 * the first mapped vnode's operation vector.
264 reles = descp->vdesc_flags;
265 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
266 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
267 break; /* bail out at end of list */
268 vps_p[i] = this_vp_p =
269 VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
271 * We're not guaranteed that any but the first vnode
272 * are of our type. Check for and don't map any
273 * that aren't. (We must always map first vp or vclean fails.)
275 if (i && (*this_vp_p == NULLVP ||
276 (*this_vp_p)->v_tag != VT_NULL)) {
279 old_vps[i] = *this_vp_p;
280 *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p);
282 * XXX - Several operations have the side effect
283 * of vrele'ing their vp's. We must account for
284 * that. (This should go away in the future.)
286 if (reles & VDESC_VP0_WILLRELE)
293 * Call the operation on the lower layer with the modified
294 * argument structure. We have to adjust a_fm to point to the
295 * lower vp's vop_ops structure.
297 if (vps_p[0] && *vps_p[0]) {
298 ap->a_ops = (*(vps_p[0]))->v_ops;
299 error = vop_vnoperate_ap(ap);
301 printf("null_bypass: no map for %s\n", descp->vdesc_name);
306 * Maintain the illusion of call-by-value
307 * by restoring vnodes in the argument structure
308 * to their original value.
310 reles = descp->vdesc_flags;
311 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
312 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
313 break; /* bail out at end of list */
315 *(vps_p[i]) = old_vps[i];
317 if (reles & VDESC_VP0_WILLUNLOCK)
318 VOP_UNLOCK(*(vps_p[i]), NULL, LK_THISLAYER, curproc);
320 if (reles & VDESC_VP0_WILLRELE)
326 * Map the possible out-going vpp
327 * (Assumes that the lower layer always returns
328 * a vref'ed vpp unless it gets an error.)
330 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
331 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
334 * XXX - even though some ops have vpp returned vp's,
335 * several ops actually vrele this before returning.
336 * We must avoid these ops.
337 * (This should go away when these ops are regularized.)
339 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
341 vppp = VOPARG_OFFSETTO(struct vnode***,
342 descp->vdesc_vpp_offset,ap);
344 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
352 * We have to carry on the locking protocol on the null layer vnodes
353 * as we progress through the tree. We also have to enforce read-only
354 * if this layer is mounted read-only.
356 * null_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
357 * struct componentname *a_cnp)
360 null_lookup(struct vop_lookup_args *ap)
362 struct componentname *cnp = ap->a_cnp;
363 struct vnode *dvp = ap->a_dvp;
364 struct thread *td = cnp->cn_td;
365 int flags = cnp->cn_flags;
366 struct vnode *vp, *ldvp, *lvp;
369 if ((flags & CNP_ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
370 (cnp->cn_nameiop == NAMEI_DELETE || cnp->cn_nameiop == NAMEI_RENAME))
373 * Although it is possible to call null_bypass(), we'll do
374 * a direct call to reduce overhead
376 ldvp = NULLVPTOLOWERVP(dvp);
378 error = VOP_LOOKUP(ldvp, NCPNULL, &lvp, NCPPNULL, cnp);
379 if (error == EJUSTRETURN && (flags & CNP_ISLASTCN) &&
380 (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
381 (cnp->cn_nameiop == NAMEI_CREATE || cnp->cn_nameiop == NAMEI_RENAME))
385 * Rely only on the PDIRUNLOCK flag which should be carefully
386 * tracked by underlying filesystem.
388 if (cnp->cn_flags & CNP_PDIRUNLOCK)
389 VOP_UNLOCK(dvp, NULL, LK_THISLAYER, td);
390 if ((error == 0 || error == EJUSTRETURN) && lvp != NULL) {
396 error = null_node_create(dvp->v_mount, lvp, &vp);
405 * Setattr call. Disallow write attempts if the layer is mounted read-only.
407 * null_setattr(struct vnodeop_desc *a_desc, struct vnode *a_vp,
408 * struct vattr *a_vap, struct ucred *a_cred,
409 * struct thread *a_td)
412 null_setattr(struct vop_setattr_args *ap)
414 struct vnode *vp = ap->a_vp;
415 struct vattr *vap = ap->a_vap;
417 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
418 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
419 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
420 (vp->v_mount->mnt_flag & MNT_RDONLY))
422 if (vap->va_size != VNOVAL) {
423 switch (vp->v_type) {
430 if (vap->va_flags != VNOVAL)
437 * Disallow write attempts if the filesystem is
440 if (vp->v_mount->mnt_flag & MNT_RDONLY)
445 return (null_bypass(&ap->a_head));
449 * We handle getattr only to change the fsid.
451 * null_getattr(struct vnode *a_vp, struct vattr *a_vap, struct ucred *a_cred,
452 * struct thread *a_td)
455 null_getattr(struct vop_getattr_args *ap)
459 if ((error = null_bypass(&ap->a_head)) != 0)
462 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
467 * Handle to disallow write access if mounted read-only.
469 * null_access(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
470 * struct thread *a_td)
473 null_access(struct vop_access_args *ap)
475 struct vnode *vp = ap->a_vp;
476 mode_t mode = ap->a_mode;
479 * Disallow write attempts on read-only layers;
480 * unless the file is a socket, fifo, or a block or
481 * character device resident on the file system.
484 switch (vp->v_type) {
488 if (vp->v_mount->mnt_flag & MNT_RDONLY)
495 return (null_bypass(&ap->a_head));
499 * We must handle open to be able to catch MNT_NODEV and friends.
501 * null_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
502 * struct thread *a_td)
505 null_open(struct vop_open_args *ap)
507 struct vnode *vp = ap->a_vp;
508 struct vnode *lvp = NULLVPTOLOWERVP(ap->a_vp);
510 if ((vp->v_mount->mnt_flag & MNT_NODEV) &&
511 (lvp->v_type == VBLK || lvp->v_type == VCHR))
514 return (null_bypass(&ap->a_head));
518 * We handle this to eliminate null FS to lower FS
519 * file moving. Don't know why we don't allow this,
520 * possibly we should.
522 * null_rename(struct vnode *a_fdvp, struct vnode *a_fvp,
523 * struct componentname *a_fcnp, struct vnode *a_tdvp,
524 * struct vnode *a_tvp, struct componentname *a_tcnp)
527 null_rename(struct vop_rename_args *ap)
529 struct vnode *tdvp = ap->a_tdvp;
530 struct vnode *fvp = ap->a_fvp;
531 struct vnode *fdvp = ap->a_fdvp;
532 struct vnode *tvp = ap->a_tvp;
534 /* Check for cross-device rename. */
535 if ((fvp->v_mount != tdvp->v_mount) ||
536 (tvp && (fvp->v_mount != tvp->v_mount))) {
548 return (null_bypass(&ap->a_head));
552 * We need to process our own vnode lock and then clear the
553 * interlock flag as it applies only to our vnode, not the
554 * vnodes below us on the stack.
556 * null_lock(struct vnode *a_vp, lwkt_tokref_t a_vlock, int a_flags,
557 * struct thread *a_td)
560 null_lock(struct vop_lock_args *ap)
562 struct vnode *vp = ap->a_vp;
563 int flags = ap->a_flags;
564 struct null_node *np = VTONULL(vp);
568 if (flags & LK_THISLAYER) {
569 if (vp->v_vnlock != NULL) {
570 /* lock is shared across layers */
571 if (flags & LK_INTERLOCK)
572 lwkt_reltoken(ap->a_vlock);
575 error = lockmgr(&np->null_lock, flags & ~LK_THISLAYER,
576 ap->a_vlock, ap->a_td);
580 if (vp->v_vnlock != NULL) {
582 * The lower level has exported a struct lock to us. Use
583 * it so that all vnodes in the stack lock and unlock
584 * simultaneously. Note: we don't DRAIN the lock as DRAIN
585 * decommissions the lock - just because our vnode is
586 * going away doesn't mean the struct lock below us is.
587 * LK_EXCLUSIVE is fine.
589 if ((flags & LK_TYPE_MASK) == LK_DRAIN) {
590 NULLFSDEBUG("null_lock: avoiding LK_DRAIN\n");
591 return(lockmgr(vp->v_vnlock,
592 (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE,
593 ap->a_vlock, ap->a_td));
595 return(lockmgr(vp->v_vnlock, flags, ap->a_vlock, ap->a_td));
598 * To prevent race conditions involving doing a lookup
599 * on "..", we have to lock the lower node, then lock our
600 * node. Most of the time it won't matter that we lock our
601 * node (as any locking would need the lower one locked
602 * first). But we can LK_DRAIN the upper lock as a step
603 * towards decomissioning it.
605 lvp = NULLVPTOLOWERVP(vp);
607 return (lockmgr(&np->null_lock, flags, ap->a_vlock, ap->a_td));
608 if (flags & LK_INTERLOCK) {
609 VI_UNLOCK(ap->a_vlock, vp);
610 flags &= ~LK_INTERLOCK;
612 if ((flags & LK_TYPE_MASK) == LK_DRAIN) {
613 error = VOP_LOCK(lvp, ap->a_vlock,
614 (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE, ap->a_td);
616 error = VOP_LOCK(lvp, ap->a_vlock, flags, ap->a_td);
619 error = lockmgr(&np->null_lock, flags, ap->a_vlock, ap->a_td);
621 VOP_UNLOCK(lvp, NULL, 0, ap->a_td);
626 * We need to process our own vnode unlock and then clear the
627 * interlock flag as it applies only to our vnode, not the
628 * vnodes below us on the stack.
630 * null_unlock(struct vnode *a_vp, lwkt_tokref_t a_vlock, int a_flags,
631 * struct thread *a_td)
634 null_unlock(struct vop_unlock_args *ap)
636 struct vnode *vp = ap->a_vp;
637 int flags = ap->a_flags;
638 struct null_node *np = VTONULL(vp);
641 if (vp->v_vnlock != NULL) {
642 if (flags & LK_THISLAYER)
643 return 0; /* the lock is shared across layers */
644 flags &= ~LK_THISLAYER;
645 return (lockmgr(vp->v_vnlock, flags | LK_RELEASE,
646 ap->a_vlock, ap->a_td));
648 lvp = NULLVPTOLOWERVP(vp);
650 return (lockmgr(&np->null_lock, flags | LK_RELEASE, ap->a_vlock, ap->a_td));
651 if ((flags & LK_THISLAYER) == 0) {
652 if (flags & LK_INTERLOCK) {
653 VI_UNLOCK(ap->a_vlock, vp);
654 flags &= ~LK_INTERLOCK;
656 VOP_UNLOCK(lvp, ap->a_vlock, flags, ap->a_td);
658 flags &= ~LK_THISLAYER;
661 return (lockmgr(&np->null_lock, flags | LK_RELEASE, ap->a_vlock, ap->a_td));
665 * null_islocked(struct vnode *a_vp, struct thread *a_td)
668 null_islocked(struct vop_islocked_args *ap)
670 struct vnode *vp = ap->a_vp;
672 if (vp->v_vnlock != NULL)
673 return (lockstatus(vp->v_vnlock, ap->a_td));
674 return (lockstatus(&VTONULL(vp)->null_lock, ap->a_td));
679 * There is no way to tell that someone issued remove/rmdir operation
680 * on the underlying filesystem. For now we just have to release lowevrp
681 * as soon as possible.
683 * null_inactive(struct vnode *a_vp, struct thread *a_td)
686 null_inactive(struct vop_inactive_args *ap)
688 struct vnode *vp = ap->a_vp;
689 struct null_node *xp = VTONULL(vp);
690 struct vnode *lowervp = xp->null_lowervp;
692 lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, ap->a_td);
693 LIST_REMOVE(xp, null_hash);
694 lockmgr(&null_hashlock, LK_RELEASE, NULL, ap->a_td);
696 xp->null_lowervp = NULLVP;
697 if (vp->v_vnlock != NULL) {
698 vp->v_vnlock = &xp->null_lock; /* we no longer share the lock */
700 VOP_UNLOCK(vp, NULL, LK_THISLAYER, ap->a_td);
705 * Now it is safe to drop references to the lower vnode.
706 * VOP_INACTIVE() will be called by vrele() if necessary.
714 * We can free memory in null_inactive, but we do this
715 * here. (Possible to guard vp->v_data to point somewhere)
717 * null_reclaim(struct vnode *a_vp, struct thread *a_td)
720 null_reclaim(struct vop_reclaim_args *ap)
722 struct vnode *vp = ap->a_vp;
723 void *vdata = vp->v_data;
726 FREE(vdata, M_NULLFSNODE);
732 * null_print(struct vnode *a_vp)
735 null_print(struct vop_print_args *ap)
737 struct vnode *vp = ap->a_vp;
739 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp));
740 if (vp->v_vnlock != NULL) {
741 printf("\tvnlock: ");
742 lockmgr_printinfo(vp->v_vnlock);
744 printf("\tnull_lock: ");
745 lockmgr_printinfo(&VTONULL(vp)->null_lock);
752 * Let an underlying filesystem do the work
754 * null_createvobject(struct vnode *vp, struct ucred *cred, struct proc *p)
757 null_createvobject(struct vop_createvobject_args *ap)
759 struct vnode *vp = ap->a_vp;
760 struct vnode *lowervp = VTONULL(vp) ? NULLVPTOLOWERVP(vp) : NULL;
763 if (vp->v_type == VNON || lowervp == NULL)
765 error = VOP_CREATEVOBJECT(lowervp, ap->a_td);
768 vp->v_flag |= VOBJBUF;
773 * We have nothing to destroy and this operation shouldn't be bypassed.
775 * null_destroyvobject(struct vnode *vp)
778 null_destroyvobject(struct vop_destroyvobject_args *ap)
780 struct vnode *vp = ap->a_vp;
782 vp->v_flag &= ~VOBJBUF;
787 * null_getvobject(struct vnode *vp, struct vm_object **objpp)
790 null_getvobject(struct vop_getvobject_args *ap)
792 struct vnode *lvp = NULLVPTOLOWERVP(ap->a_vp);
796 return (VOP_GETVOBJECT(lvp, ap->a_objpp));
800 * Global vfs data structures
802 struct vnodeopv_entry_desc null_vnodeop_entries[] = {
803 { &vop_default_desc, (void *) null_bypass },
804 { &vop_access_desc, (void *) null_access },
805 { &vop_createvobject_desc, (void *) null_createvobject },
806 { &vop_destroyvobject_desc, (void *) null_destroyvobject },
807 { &vop_getattr_desc, (void *) null_getattr },
808 { &vop_getvobject_desc, (void *) null_getvobject },
809 { &vop_inactive_desc, (void *) null_inactive },
810 { &vop_islocked_desc, (void *) null_islocked },
811 { &vop_lock_desc, (void *) null_lock },
812 { &vop_lookup_desc, (void *) null_lookup },
813 { &vop_open_desc, (void *) null_open },
814 { &vop_print_desc, (void *) null_print },
815 { &vop_reclaim_desc, (void *) null_reclaim },
816 { &vop_rename_desc, (void *) null_rename },
817 { &vop_setattr_desc, (void *) null_setattr },
818 { &vop_unlock_desc, (void *) null_unlock },