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
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12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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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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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 1.18 2004/10/12 19:21:04 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_resolve(struct vop_resolve_args *ap);
195 static int null_revoke(struct vop_revoke_args *ap);
196 static int null_access(struct vop_access_args *ap);
197 static int null_createvobject(struct vop_createvobject_args *ap);
198 static int null_destroyvobject(struct vop_destroyvobject_args *ap);
199 static int null_getattr(struct vop_getattr_args *ap);
200 static int null_getvobject(struct vop_getvobject_args *ap);
201 static int null_inactive(struct vop_inactive_args *ap);
202 static int null_islocked(struct vop_islocked_args *ap);
203 static int null_lock(struct vop_lock_args *ap);
204 static int null_lookup(struct vop_lookup_args *ap);
205 static int null_open(struct vop_open_args *ap);
206 static int null_print(struct vop_print_args *ap);
207 static int null_reclaim(struct vop_reclaim_args *ap);
208 static int null_rename(struct vop_rename_args *ap);
209 static int null_setattr(struct vop_setattr_args *ap);
210 static int null_unlock(struct vop_unlock_args *ap);
213 * This is the 10-Apr-92 bypass routine.
214 * This version has been optimized for speed, throwing away some
215 * safety checks. It should still always work, but it's not as
216 * robust to programmer errors.
218 * In general, we map all vnodes going down and unmap them on the way back.
219 * As an exception to this, vnodes can be marked "unmapped" by setting
220 * the Nth bit in operation's vdesc_flags.
222 * Also, some BSD vnode operations have the side effect of vrele'ing
223 * their arguments. With stacking, the reference counts are held
224 * by the upper node, not the lower one, so we must handle these
225 * side-effects here. This is not of concern in Sun-derived systems
226 * since there are no such side-effects.
228 * This makes the following assumptions:
229 * - only one returned vpp
230 * - no INOUT vpp's (Sun's vop_open has one of these)
231 * - the vnode operation vector of the first vnode should be used
232 * to determine what implementation of the op should be invoked
233 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
234 * problems on rmdir'ing mount points and renaming?)
236 * null_bypass(struct vnodeop_desc *a_desc, ...)
239 null_bypass(struct vop_generic_args *ap)
241 struct vnode **this_vp_p;
243 struct vnode *old_vps[VDESC_MAX_VPS];
244 struct vnode **vps_p[VDESC_MAX_VPS];
245 struct vnode ***vppp;
246 struct vnodeop_desc *descp = ap->a_desc;
250 printf ("null_bypass: %s\n", descp->vdesc_name);
254 * We require at least one vp.
256 if (descp->vdesc_vp_offsets == NULL ||
257 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
258 panic ("null_bypass: no vp's in map");
262 * Map the vnodes going in.
264 reles = descp->vdesc_flags;
265 for (i = 0; i < VDESC_MAX_VPS; ++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 *this_vp_p = NULLVPTOLOWERVP(*this_vp_p);
282 * Several operations have the side effect of vrele'ing
283 * their vp's. We must account for that in the lower
286 if (reles & (VDESC_VP0_WILLRELE << i))
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 by restoring vnodes in the
307 * argument structure to their original value.
309 reles = descp->vdesc_flags;
310 for (i = 0; i < VDESC_MAX_VPS; ++i) {
311 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
312 break; /* bail out at end of list */
314 *(vps_p[i]) = old_vps[i];
317 * Since we operated on the lowervp's instead of the
318 * null node vp's, we have to adjust the null node
319 * vp's based on what the VOP did to the lower vp.
321 * Note: the unlock case only occurs with rename.
322 * tdvp and tvp are both locked on call and must be
323 * unlocked on return.
325 * Unlock semantics indicate that if two locked vp's
326 * are passed and they are the same vp, they are only
327 * actually locked once.
329 if (reles & (VDESC_VP0_WILLUNLOCK << i)) {
330 VOP_UNLOCK(old_vps[i], LK_THISLAYER, curthread);
331 for (j = i + 1; j < VDESC_MAX_VPS; ++j) {
332 if (descp->vdesc_vp_offsets[j] == VDESC_NO_OFFSET)
334 if (old_vps[i] == old_vps[j]) {
335 reles &= ~(1 << (VDESC_VP0_WILLUNLOCK << j));
340 if (reles & (VDESC_VP0_WILLRELE << i))
346 * Map the possible out-going vpp
347 * (Assumes that the lower layer always returns
348 * a vref'ed vpp unless it gets an error.)
350 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
351 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
354 * XXX - even though some ops have vpp returned vp's,
355 * several ops actually vrele this before returning.
356 * We must avoid these ops.
357 * (This should go away when these ops are regularized.)
359 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
361 vppp = VOPARG_OFFSETTO(struct vnode***,
362 descp->vdesc_vpp_offset,ap);
364 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
372 * We have to carry on the locking protocol on the null layer vnodes
373 * as we progress through the tree. We also have to enforce read-only
374 * if this layer is mounted read-only.
376 * null_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
377 * struct componentname *a_cnp)
380 null_lookup(struct vop_lookup_args *ap)
382 struct componentname *cnp = ap->a_cnp;
383 struct vnode *dvp = ap->a_dvp;
384 struct thread *td = cnp->cn_td;
385 int flags = cnp->cn_flags;
386 struct vnode *vp, *ldvp, *lvp;
389 if ((flags & CNP_ISLASTCN) &&
390 (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
391 (cnp->cn_nameiop == NAMEI_DELETE ||
392 cnp->cn_nameiop == NAMEI_RENAME)) {
395 ldvp = NULLVPTOLOWERVP(dvp);
398 * If we are doing a ".." lookup we must release the lock on dvp
399 * now, before we run a lookup in the underlying fs, or we may
400 * deadlock. If we do this we must protect ldvp by ref'ing it.
402 if (flags & CNP_ISDOTDOT) {
404 VOP_UNLOCK(dvp, LK_THISLAYER, td);
408 * Due to the non-deterministic nature of the handling of the
409 * parent directory lock by lookup, we cannot call null_bypass()
410 * here. We must make a direct call. It's faster to do a direct
414 error = VOP_LOOKUP(ldvp, &lvp, cnp);
415 if (error == EJUSTRETURN && (flags & CNP_ISLASTCN) &&
416 (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
417 (cnp->cn_nameiop == NAMEI_CREATE ||
418 cnp->cn_nameiop == NAMEI_RENAME)) {
422 if ((error == 0 || error == EJUSTRETURN) && lvp != NULL) {
428 error = null_node_create(dvp->v_mount, lvp, &vp);
435 * The underlying fs will set PDIRUNLOCK if it unlocked the parent
436 * directory, which means we have to follow suit in the nullfs layer.
437 * Note that the parent directory may have already been unlocked due
438 * to the ".." case. Note that use of cnp->cn_flags instead of flags.
440 if (flags & CNP_ISDOTDOT) {
441 if ((cnp->cn_flags & CNP_PDIRUNLOCK) == 0)
442 VOP_LOCK(dvp, LK_THISLAYER | LK_EXCLUSIVE, td);
444 } else if (cnp->cn_flags & CNP_PDIRUNLOCK) {
445 VOP_UNLOCK(dvp, LK_THISLAYER, td);
451 * Setattr call. Disallow write attempts if the layer is mounted read-only.
453 * null_setattr(struct vnodeop_desc *a_desc, struct vnode *a_vp,
454 * struct vattr *a_vap, struct ucred *a_cred,
455 * struct thread *a_td)
458 null_setattr(struct vop_setattr_args *ap)
460 struct vnode *vp = ap->a_vp;
461 struct vattr *vap = ap->a_vap;
463 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
464 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
465 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
466 (vp->v_mount->mnt_flag & MNT_RDONLY))
468 if (vap->va_size != VNOVAL) {
469 switch (vp->v_type) {
476 if (vap->va_flags != VNOVAL)
483 * Disallow write attempts if the filesystem is
486 if (vp->v_mount->mnt_flag & MNT_RDONLY)
491 return (null_bypass(&ap->a_head));
495 * We handle getattr only to change the fsid.
497 * null_getattr(struct vnode *a_vp, struct vattr *a_vap, struct ucred *a_cred,
498 * struct thread *a_td)
501 null_getattr(struct vop_getattr_args *ap)
505 if ((error = null_bypass(&ap->a_head)) != 0)
508 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
513 * Resolve a locked ncp at the nullfs layer.
516 null_resolve(struct vop_resolve_args *ap)
518 return(vop_noresolve(ap));
522 * revoke is VX locked, we can't go through null_bypass
525 null_revoke(struct vop_revoke_args *ap)
527 struct null_node *np;
530 np = VTONULL(ap->a_vp);
532 if ((lvp = np->null_lowervp) != NULL) {
534 VOP_REVOKE(lvp, ap->a_flags);
542 * Handle to disallow write access if mounted read-only.
544 * null_access(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
545 * struct thread *a_td)
548 null_access(struct vop_access_args *ap)
550 struct vnode *vp = ap->a_vp;
551 mode_t mode = ap->a_mode;
554 * Disallow write attempts on read-only layers;
555 * unless the file is a socket, fifo, or a block or
556 * character device resident on the file system.
559 switch (vp->v_type) {
563 if (vp->v_mount->mnt_flag & MNT_RDONLY)
570 return (null_bypass(&ap->a_head));
574 * We must handle open to be able to catch MNT_NODEV and friends.
576 * null_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
577 * struct thread *a_td)
580 null_open(struct vop_open_args *ap)
582 struct vnode *vp = ap->a_vp;
583 struct vnode *lvp = NULLVPTOLOWERVP(ap->a_vp);
585 if ((vp->v_mount->mnt_flag & MNT_NODEV) &&
586 (lvp->v_type == VBLK || lvp->v_type == VCHR))
589 return (null_bypass(&ap->a_head));
593 * We handle this to eliminate null FS to lower FS
594 * file moving. Don't know why we don't allow this,
595 * possibly we should.
597 * null_rename(struct vnode *a_fdvp, struct vnode *a_fvp,
598 * struct componentname *a_fcnp, struct vnode *a_tdvp,
599 * struct vnode *a_tvp, struct componentname *a_tcnp)
602 null_rename(struct vop_rename_args *ap)
604 struct vnode *tdvp = ap->a_tdvp;
605 struct vnode *fvp = ap->a_fvp;
606 struct vnode *fdvp = ap->a_fdvp;
607 struct vnode *tvp = ap->a_tvp;
609 /* Check for cross-device rename. */
610 if ((fvp->v_mount != tdvp->v_mount) ||
611 (tvp && (fvp->v_mount != tvp->v_mount))) {
623 return (null_bypass(&ap->a_head));
627 * A special flag, LK_THISLAYER, causes the locking function to operate
628 * ONLY on the nullfs layer. Otherwise we are responsible for locking not
629 * only our layer, but the lower layer as well.
631 * null_lock(struct vnode *a_vp, int a_flags, struct thread *a_td)
634 null_lock(struct vop_lock_args *ap)
636 struct vnode *vp = ap->a_vp;
637 int flags = ap->a_flags;
638 struct null_node *np = VTONULL(vp);
643 * Lock the nullfs layer first, disposing of the interlock in the
646 KKASSERT((flags & LK_INTERLOCK) == 0);
647 error = lockmgr(&vp->v_lock, flags & ~LK_THISLAYER,
651 * If locking only the nullfs layer, or if there is no lower layer,
652 * or if an error occured while attempting to lock the nullfs layer,
655 * np can be NULL is the vnode is being recycled from a previous
658 if ((flags & LK_THISLAYER) || np == NULL ||
659 np->null_lowervp == NULL || error) {
664 * Lock the underlying vnode. If we are draining we should not drain
665 * the underlying vnode, since it is not being destroyed, but we do
666 * lock it exclusively in that case. Note that any interlocks have
667 * already been disposed of above.
669 lvp = np->null_lowervp;
670 if ((flags & LK_TYPE_MASK) == LK_DRAIN) {
671 NULLFSDEBUG("null_lock: avoiding LK_DRAIN\n");
672 error = vn_lock(lvp, (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE,
675 error = vn_lock(lvp, flags, ap->a_td);
679 * If an error occured we have to undo our nullfs lock, then return
680 * the original error.
683 lockmgr(&vp->v_lock, LK_RELEASE, NULL, ap->a_td);
688 * A special flag, LK_THISLAYER, causes the unlocking function to operate
689 * ONLY on the nullfs layer. Otherwise we are responsible for unlocking not
690 * only our layer, but the lower layer as well.
692 * null_unlock(struct vnode *a_vp, int a_flags, struct thread *a_td)
695 null_unlock(struct vop_unlock_args *ap)
697 struct vnode *vp = ap->a_vp;
698 int flags = ap->a_flags;
699 struct null_node *np = VTONULL(vp);
703 KKASSERT((flags & LK_INTERLOCK) == 0);
707 if (flags & LK_THISLAYER) {
708 error = lockmgr(&vp->v_lock,
709 (flags & ~LK_THISLAYER) | LK_RELEASE,
715 * If there is no underlying vnode the lock operation occurs at
716 * the nullfs layer. np can be NULL is the vnode is being recycled
717 * from a previous hash collision.
719 if (np == NULL || (lvp = np->null_lowervp) == NULL) {
720 error = lockmgr(&vp->v_lock, flags | LK_RELEASE,
726 * Unlock the lower layer first, then our nullfs layer.
728 VOP_UNLOCK(lvp, flags, ap->a_td);
729 error = lockmgr(&vp->v_lock, flags | LK_RELEASE, NULL, ap->a_td);
734 * null_islocked(struct vnode *a_vp, struct thread *a_td)
736 * If a lower layer exists return the lock status of the lower layer,
737 * otherwise return the lock status of our nullfs layer.
740 null_islocked(struct vop_islocked_args *ap)
742 struct vnode *vp = ap->a_vp;
744 struct null_node *np = VTONULL(vp);
747 lvp = np->null_lowervp;
749 error = lockstatus(&vp->v_lock, ap->a_td);
751 error = VOP_ISLOCKED(lvp, ap->a_td);
757 * The vnode is no longer active. However, the new VFS API may retain
758 * the node in the vfs cache. There is no way to tell that someone issued
759 * a remove/rmdir operation on the underlying filesystem (yet), but we can't
760 * remove the lowervp reference here.
762 * null_inactive(struct vnode *a_vp, struct thread *a_td)
765 null_inactive(struct vop_inactive_args *ap)
767 /*struct vnode *vp = ap->a_vp;*/
768 /*struct null_node *np = VTONULL(vp);*/
771 * At the moment don't do anything here. All the rest of the code
772 * assumes that lowervp will remain inact, and the inactive nullvp
773 * may be reactivated at any time. XXX I'm not sure why the 4.x code
778 * Now it is safe to release our nullfs layer vnode.
784 * We can free memory in null_inactive, but we do this
785 * here. (Possible to guard vp->v_data to point somewhere)
787 * null_reclaim(struct vnode *a_vp, struct thread *a_td)
790 null_reclaim(struct vop_reclaim_args *ap)
792 struct vnode *vp = ap->a_vp;
793 struct vnode *lowervp;
794 struct null_node *np;
799 * null_lowervp reference to lowervp. The lower vnode's
800 * inactive routine may or may not be called when we do the
805 lowervp = np->null_lowervp;
806 np->null_lowervp = NULLVP;
809 free(np, M_NULLFSNODE);
815 * null_print(struct vnode *a_vp)
818 null_print(struct vop_print_args *ap)
820 struct vnode *vp = ap->a_vp;
821 struct null_node *np = VTONULL(vp);
824 printf ("\ttag VT_NULLFS, vp=%p, NULL v_data!\n", vp);
827 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, np->null_lowervp);
828 if (np->null_lowervp != NULL) {
829 printf("\tlowervp_lock: ");
830 lockmgr_printinfo(&np->null_lowervp->v_lock);
832 printf("\tnull_lock: ");
833 lockmgr_printinfo(&vp->v_lock);
840 * Let an underlying filesystem do the work
842 * null_createvobject(struct vnode *vp, struct ucred *cred, struct proc *p)
845 null_createvobject(struct vop_createvobject_args *ap)
847 struct vnode *vp = ap->a_vp;
848 struct vnode *lowervp = VTONULL(vp) ? NULLVPTOLOWERVP(vp) : NULL;
851 if (vp->v_type == VNON || lowervp == NULL)
853 error = VOP_CREATEVOBJECT(lowervp, ap->a_td);
856 vp->v_flag |= VOBJBUF;
861 * We have nothing to destroy and this operation shouldn't be bypassed.
863 * null_destroyvobject(struct vnode *vp)
866 null_destroyvobject(struct vop_destroyvobject_args *ap)
868 struct vnode *vp = ap->a_vp;
870 vp->v_flag &= ~VOBJBUF;
875 * null_getvobject(struct vnode *vp, struct vm_object **objpp)
877 * Note that this can be called when a vnode is being recycled, and
878 * v_data may be NULL in that case if nullfs had to recycle a vnode
879 * due to a null_node collision.
882 null_getvobject(struct vop_getvobject_args *ap)
886 if (ap->a_vp->v_data == NULL)
889 lvp = NULLVPTOLOWERVP(ap->a_vp);
892 return (VOP_GETVOBJECT(lvp, ap->a_objpp));
896 * Global vfs data structures
898 struct vnodeopv_entry_desc null_vnodeop_entries[] = {
899 { &vop_default_desc, (void *) null_bypass },
900 { &vop_resolve_desc, (void *) null_resolve },
901 { &vop_access_desc, (void *) null_access },
902 { &vop_createvobject_desc, (void *) null_createvobject },
903 { &vop_destroyvobject_desc, (void *) null_destroyvobject },
904 { &vop_getattr_desc, (void *) null_getattr },
905 { &vop_getvobject_desc, (void *) null_getvobject },
906 { &vop_inactive_desc, (void *) null_inactive },
907 { &vop_islocked_desc, (void *) null_islocked },
908 { &vop_lock_desc, (void *) null_lock },
909 { &vop_lookup_desc, (void *) null_lookup },
910 { &vop_open_desc, (void *) null_open },
911 { &vop_print_desc, (void *) null_print },
912 { &vop_reclaim_desc, (void *) null_reclaim },
913 { &vop_rename_desc, (void *) null_rename },
914 { &vop_setattr_desc, (void *) null_setattr },
915 { &vop_unlock_desc, (void *) null_unlock },
916 { &vop_revoke_desc, (void *) null_revoke },