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.
16 * 3. All advertising materials mentioning features or use of this software
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
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 1.22 2005/02/15 08:32:18 joerg 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_nresolve(struct vop_nresolve_args *ap);
195 static int null_ncreate(struct vop_ncreate_args *ap);
196 static int null_nmkdir(struct vop_nmkdir_args *ap);
197 static int null_nremove(struct vop_nremove_args *ap);
198 static int null_nrmdir(struct vop_nrmdir_args *ap);
199 static int null_nrename(struct vop_nrename_args *ap);
201 static int null_revoke(struct vop_revoke_args *ap);
202 static int null_access(struct vop_access_args *ap);
203 static int null_createvobject(struct vop_createvobject_args *ap);
204 static int null_destroyvobject(struct vop_destroyvobject_args *ap);
205 static int null_getattr(struct vop_getattr_args *ap);
206 static int null_getvobject(struct vop_getvobject_args *ap);
207 static int null_inactive(struct vop_inactive_args *ap);
208 static int null_islocked(struct vop_islocked_args *ap);
209 static int null_lock(struct vop_lock_args *ap);
210 static int null_lookup(struct vop_lookup_args *ap);
211 static int null_open(struct vop_open_args *ap);
212 static int null_print(struct vop_print_args *ap);
213 static int null_reclaim(struct vop_reclaim_args *ap);
214 static int null_rename(struct vop_rename_args *ap);
215 static int null_setattr(struct vop_setattr_args *ap);
216 static int null_unlock(struct vop_unlock_args *ap);
219 * This is the 10-Apr-92 bypass routine.
220 * This version has been optimized for speed, throwing away some
221 * safety checks. It should still always work, but it's not as
222 * robust to programmer errors.
224 * In general, we map all vnodes going down and unmap them on the way back.
225 * As an exception to this, vnodes can be marked "unmapped" by setting
226 * the Nth bit in operation's vdesc_flags.
228 * Also, some BSD vnode operations have the side effect of vrele'ing
229 * their arguments. With stacking, the reference counts are held
230 * by the upper node, not the lower one, so we must handle these
231 * side-effects here. This is not of concern in Sun-derived systems
232 * since there are no such side-effects.
234 * This makes the following assumptions:
235 * - only one returned vpp
236 * - no INOUT vpp's (Sun's vop_open has one of these)
237 * - the vnode operation vector of the first vnode should be used
238 * to determine what implementation of the op should be invoked
239 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
240 * problems on rmdir'ing mount points and renaming?)
242 * null_bypass(struct vnodeop_desc *a_desc, ...)
245 null_bypass(struct vop_generic_args *ap)
247 struct vnode **this_vp_p;
249 struct vnode *old_vps[VDESC_MAX_VPS];
250 struct vnode **vps_p[VDESC_MAX_VPS];
251 struct vnode ***vppp;
252 struct vnodeop_desc *descp = ap->a_desc;
256 printf ("null_bypass: %s\n", descp->vdesc_name);
260 * We require at least one vp.
262 if (descp->vdesc_vp_offsets == NULL ||
263 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
264 panic ("null_bypass: no vp's in map");
268 * Map the vnodes going in.
270 reles = descp->vdesc_flags;
271 for (i = 0; i < VDESC_MAX_VPS; ++i) {
272 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
273 break; /* bail out at end of list */
274 vps_p[i] = this_vp_p =
275 VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
277 * We're not guaranteed that any but the first vnode
278 * are of our type. Check for and don't map any
279 * that aren't. (We must always map first vp or vclean fails.)
281 if (i && (*this_vp_p == NULLVP ||
282 (*this_vp_p)->v_tag != VT_NULL)) {
285 old_vps[i] = *this_vp_p;
286 *this_vp_p = NULLVPTOLOWERVP(*this_vp_p);
288 * Several operations have the side effect of vrele'ing
289 * their vp's. We must account for that in the lower
292 if (reles & (VDESC_VP0_WILLRELE << i))
299 * Call the operation on the lower layer with the modified
300 * argument structure. We have to adjust a_fm to point to the
301 * lower vp's vop_ops structure.
303 if (vps_p[0] && *vps_p[0]) {
304 ap->a_ops = *(*(vps_p[0]))->v_ops;
305 error = vop_vnoperate_ap(ap);
307 printf("null_bypass: no map for %s\n", descp->vdesc_name);
312 * Maintain the illusion of call-by-value by restoring vnodes in the
313 * argument structure to their original value.
315 reles = descp->vdesc_flags;
316 for (i = 0; i < VDESC_MAX_VPS; ++i) {
317 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
318 break; /* bail out at end of list */
320 *(vps_p[i]) = old_vps[i];
323 * Since we operated on the lowervp's instead of the
324 * null node vp's, we have to adjust the null node
325 * vp's based on what the VOP did to the lower vp.
327 * Note: the unlock case only occurs with rename.
328 * tdvp and tvp are both locked on call and must be
329 * unlocked on return.
331 * Unlock semantics indicate that if two locked vp's
332 * are passed and they are the same vp, they are only
333 * actually locked once.
335 if (reles & (VDESC_VP0_WILLUNLOCK << i)) {
336 VOP_UNLOCK(old_vps[i], LK_THISLAYER, curthread);
337 for (j = i + 1; j < VDESC_MAX_VPS; ++j) {
338 if (descp->vdesc_vp_offsets[j] == VDESC_NO_OFFSET)
340 if (old_vps[i] == old_vps[j]) {
341 reles &= ~(1 << (VDESC_VP0_WILLUNLOCK << j));
346 if (reles & (VDESC_VP0_WILLRELE << i))
352 * Map the possible out-going vpp
353 * (Assumes that the lower layer always returns
354 * a vref'ed vpp unless it gets an error.)
356 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
357 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
360 * XXX - even though some ops have vpp returned vp's,
361 * several ops actually vrele this before returning.
362 * We must avoid these ops.
363 * (This should go away when these ops are regularized.)
365 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
367 vppp = VOPARG_OFFSETTO(struct vnode***,
368 descp->vdesc_vpp_offset,ap);
370 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
378 * We have to carry on the locking protocol on the null layer vnodes
379 * as we progress through the tree. We also have to enforce read-only
380 * if this layer is mounted read-only.
382 * null_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
383 * struct componentname *a_cnp)
386 null_lookup(struct vop_lookup_args *ap)
388 struct componentname *cnp = ap->a_cnp;
389 struct vnode *dvp = ap->a_dvp;
390 struct thread *td = cnp->cn_td;
391 int flags = cnp->cn_flags;
392 struct vnode *vp, *ldvp, *lvp;
395 if ((dvp->v_mount->mnt_flag & MNT_RDONLY) &&
396 (cnp->cn_nameiop == NAMEI_DELETE ||
397 cnp->cn_nameiop == NAMEI_RENAME)) {
400 ldvp = NULLVPTOLOWERVP(dvp);
403 * If we are doing a ".." lookup we must release the lock on dvp
404 * now, before we run a lookup in the underlying fs, or we may
405 * deadlock. If we do this we must protect ldvp by ref'ing it.
407 if (flags & CNP_ISDOTDOT) {
409 VOP_UNLOCK(dvp, LK_THISLAYER, td);
413 * Due to the non-deterministic nature of the handling of the
414 * parent directory lock by lookup, we cannot call null_bypass()
415 * here. We must make a direct call. It's faster to do a direct
419 error = VOP_LOOKUP(ldvp, &lvp, cnp);
420 if (error == EJUSTRETURN &&
421 (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
422 (cnp->cn_nameiop == NAMEI_CREATE ||
423 cnp->cn_nameiop == NAMEI_RENAME)) {
427 if ((error == 0 || error == EJUSTRETURN) && lvp != NULL) {
433 error = null_node_create(dvp->v_mount, lvp, &vp);
440 * The underlying fs will set PDIRUNLOCK if it unlocked the parent
441 * directory, which means we have to follow suit in the nullfs layer.
442 * Note that the parent directory may have already been unlocked due
443 * to the ".." case. Note that use of cnp->cn_flags instead of flags.
445 if (flags & CNP_ISDOTDOT) {
446 if ((cnp->cn_flags & CNP_PDIRUNLOCK) == 0)
447 VOP_LOCK(dvp, LK_THISLAYER | LK_EXCLUSIVE, td);
449 } else if (cnp->cn_flags & CNP_PDIRUNLOCK) {
450 VOP_UNLOCK(dvp, LK_THISLAYER, td);
456 * Setattr call. Disallow write attempts if the layer is mounted read-only.
458 * null_setattr(struct vnodeop_desc *a_desc, struct vnode *a_vp,
459 * struct vattr *a_vap, struct ucred *a_cred,
460 * struct thread *a_td)
463 null_setattr(struct vop_setattr_args *ap)
465 struct vnode *vp = ap->a_vp;
466 struct vattr *vap = ap->a_vap;
468 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
469 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
470 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
471 (vp->v_mount->mnt_flag & MNT_RDONLY))
473 if (vap->va_size != VNOVAL) {
474 switch (vp->v_type) {
481 if (vap->va_flags != VNOVAL)
488 * Disallow write attempts if the filesystem is
491 if (vp->v_mount->mnt_flag & MNT_RDONLY)
496 return (null_bypass(&ap->a_head));
500 * We handle getattr only to change the fsid.
502 * null_getattr(struct vnode *a_vp, struct vattr *a_vap, struct ucred *a_cred,
503 * struct thread *a_td)
506 null_getattr(struct vop_getattr_args *ap)
510 if ((error = null_bypass(&ap->a_head)) != 0)
513 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
518 * Resolve a locked ncp at the nullfs layer.
521 null_nresolve(struct vop_nresolve_args *ap)
523 return(vop_compat_nresolve(ap));
530 null_ncreate(struct vop_ncreate_args *ap)
532 return(vop_compat_ncreate(ap));
536 null_nmkdir(struct vop_nmkdir_args *ap)
538 return(vop_compat_nmkdir(ap));
542 null_nremove(struct vop_nremove_args *ap)
544 return(vop_compat_nremove(ap));
548 null_nrmdir(struct vop_nrmdir_args *ap)
550 return(vop_compat_nrmdir(ap));
554 null_nrename(struct vop_nrename_args *ap)
556 return(vop_compat_nrename(ap));
560 * revoke is VX locked, we can't go through null_bypass
563 null_revoke(struct vop_revoke_args *ap)
565 struct null_node *np;
568 np = VTONULL(ap->a_vp);
570 if ((lvp = np->null_lowervp) != NULL) {
572 VOP_REVOKE(lvp, ap->a_flags);
581 * Handle to disallow write access if mounted read-only.
583 * null_access(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
584 * struct thread *a_td)
587 null_access(struct vop_access_args *ap)
589 struct vnode *vp = ap->a_vp;
590 mode_t mode = ap->a_mode;
593 * Disallow write attempts on read-only layers;
594 * unless the file is a socket, fifo, or a block or
595 * character device resident on the file system.
598 switch (vp->v_type) {
602 if (vp->v_mount->mnt_flag & MNT_RDONLY)
609 return (null_bypass(&ap->a_head));
613 * We must handle open to be able to catch MNT_NODEV and friends.
615 * null_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
616 * struct thread *a_td)
619 null_open(struct vop_open_args *ap)
621 struct vnode *vp = ap->a_vp;
622 struct vnode *lvp = NULLVPTOLOWERVP(ap->a_vp);
624 if ((vp->v_mount->mnt_flag & MNT_NODEV) &&
625 (lvp->v_type == VBLK || lvp->v_type == VCHR))
628 return (null_bypass(&ap->a_head));
632 * We handle this to eliminate null FS to lower FS
633 * file moving. Don't know why we don't allow this,
634 * possibly we should.
636 * null_rename(struct vnode *a_fdvp, struct vnode *a_fvp,
637 * struct componentname *a_fcnp, struct vnode *a_tdvp,
638 * struct vnode *a_tvp, struct componentname *a_tcnp)
641 null_rename(struct vop_rename_args *ap)
643 struct vnode *tdvp = ap->a_tdvp;
644 struct vnode *fvp = ap->a_fvp;
645 struct vnode *fdvp = ap->a_fdvp;
646 struct vnode *tvp = ap->a_tvp;
648 /* Check for cross-device rename. */
649 if ((fvp->v_mount != tdvp->v_mount) ||
650 (tvp && (fvp->v_mount != tvp->v_mount))) {
662 return (null_bypass(&ap->a_head));
666 * A special flag, LK_THISLAYER, causes the locking function to operate
667 * ONLY on the nullfs layer. Otherwise we are responsible for locking not
668 * only our layer, but the lower layer as well.
670 * null_lock(struct vnode *a_vp, int a_flags, struct thread *a_td)
673 null_lock(struct vop_lock_args *ap)
675 struct vnode *vp = ap->a_vp;
676 int flags = ap->a_flags;
677 struct null_node *np = VTONULL(vp);
682 * Lock the nullfs layer first, disposing of the interlock in the
685 KKASSERT((flags & LK_INTERLOCK) == 0);
686 error = lockmgr(&vp->v_lock, flags & ~LK_THISLAYER,
690 * If locking only the nullfs layer, or if there is no lower layer,
691 * or if an error occured while attempting to lock the nullfs layer,
694 * np can be NULL is the vnode is being recycled from a previous
697 if ((flags & LK_THISLAYER) || np == NULL ||
698 np->null_lowervp == NULL || error) {
703 * Lock the underlying vnode. If we are draining we should not drain
704 * the underlying vnode, since it is not being destroyed, but we do
705 * lock it exclusively in that case. Note that any interlocks have
706 * already been disposed of above.
708 lvp = np->null_lowervp;
709 if ((flags & LK_TYPE_MASK) == LK_DRAIN) {
710 NULLFSDEBUG("null_lock: avoiding LK_DRAIN\n");
711 error = vn_lock(lvp, (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE,
714 error = vn_lock(lvp, flags, ap->a_td);
718 * If an error occured we have to undo our nullfs lock, then return
719 * the original error.
722 lockmgr(&vp->v_lock, LK_RELEASE, NULL, ap->a_td);
727 * A special flag, LK_THISLAYER, causes the unlocking function to operate
728 * ONLY on the nullfs layer. Otherwise we are responsible for unlocking not
729 * only our layer, but the lower layer as well.
731 * null_unlock(struct vnode *a_vp, int a_flags, struct thread *a_td)
734 null_unlock(struct vop_unlock_args *ap)
736 struct vnode *vp = ap->a_vp;
737 int flags = ap->a_flags;
738 struct null_node *np = VTONULL(vp);
742 KKASSERT((flags & LK_INTERLOCK) == 0);
746 if (flags & LK_THISLAYER) {
747 error = lockmgr(&vp->v_lock,
748 (flags & ~LK_THISLAYER) | LK_RELEASE,
754 * If there is no underlying vnode the lock operation occurs at
755 * the nullfs layer. np can be NULL is the vnode is being recycled
756 * from a previous hash collision.
758 if (np == NULL || (lvp = np->null_lowervp) == NULL) {
759 error = lockmgr(&vp->v_lock, flags | LK_RELEASE,
765 * Unlock the lower layer first, then our nullfs layer.
767 VOP_UNLOCK(lvp, flags, ap->a_td);
768 error = lockmgr(&vp->v_lock, flags | LK_RELEASE, NULL, ap->a_td);
773 * null_islocked(struct vnode *a_vp, struct thread *a_td)
775 * If a lower layer exists return the lock status of the lower layer,
776 * otherwise return the lock status of our nullfs layer.
779 null_islocked(struct vop_islocked_args *ap)
781 struct vnode *vp = ap->a_vp;
783 struct null_node *np = VTONULL(vp);
786 lvp = np->null_lowervp;
788 error = lockstatus(&vp->v_lock, ap->a_td);
790 error = VOP_ISLOCKED(lvp, ap->a_td);
796 * The vnode is no longer active. However, the new VFS API may retain
797 * the node in the vfs cache. There is no way to tell that someone issued
798 * a remove/rmdir operation on the underlying filesystem (yet), but we can't
799 * remove the lowervp reference here.
801 * null_inactive(struct vnode *a_vp, struct thread *a_td)
804 null_inactive(struct vop_inactive_args *ap)
806 /*struct vnode *vp = ap->a_vp;*/
807 /*struct null_node *np = VTONULL(vp);*/
810 * At the moment don't do anything here. All the rest of the code
811 * assumes that lowervp will remain inact, and the inactive nullvp
812 * may be reactivated at any time. XXX I'm not sure why the 4.x code
817 * Now it is safe to release our nullfs layer vnode.
823 * We can free memory in null_inactive, but we do this
824 * here. (Possible to guard vp->v_data to point somewhere)
826 * null_reclaim(struct vnode *a_vp, struct thread *a_td)
829 null_reclaim(struct vop_reclaim_args *ap)
831 struct vnode *vp = ap->a_vp;
832 struct vnode *lowervp;
833 struct null_node *np;
838 * null_lowervp reference to lowervp. The lower vnode's
839 * inactive routine may or may not be called when we do the
844 lowervp = np->null_lowervp;
845 np->null_lowervp = NULLVP;
848 free(np, M_NULLFSNODE);
854 * null_print(struct vnode *a_vp)
857 null_print(struct vop_print_args *ap)
859 struct vnode *vp = ap->a_vp;
860 struct null_node *np = VTONULL(vp);
863 printf ("\ttag VT_NULLFS, vp=%p, NULL v_data!\n", vp);
866 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, np->null_lowervp);
867 if (np->null_lowervp != NULL) {
868 printf("\tlowervp_lock: ");
869 lockmgr_printinfo(&np->null_lowervp->v_lock);
871 printf("\tnull_lock: ");
872 lockmgr_printinfo(&vp->v_lock);
879 * Let an underlying filesystem do the work
881 * null_createvobject(struct vnode *vp, struct ucred *cred, struct proc *p)
884 null_createvobject(struct vop_createvobject_args *ap)
886 struct vnode *vp = ap->a_vp;
887 struct vnode *lowervp = VTONULL(vp) ? NULLVPTOLOWERVP(vp) : NULL;
890 if (vp->v_type == VNON || lowervp == NULL)
892 error = VOP_CREATEVOBJECT(lowervp, ap->a_td);
895 vp->v_flag |= VOBJBUF;
900 * We have nothing to destroy and this operation shouldn't be bypassed.
902 * null_destroyvobject(struct vnode *vp)
905 null_destroyvobject(struct vop_destroyvobject_args *ap)
907 struct vnode *vp = ap->a_vp;
909 vp->v_flag &= ~VOBJBUF;
914 * null_getvobject(struct vnode *vp, struct vm_object **objpp)
916 * Note that this can be called when a vnode is being recycled, and
917 * v_data may be NULL in that case if nullfs had to recycle a vnode
918 * due to a null_node collision.
921 null_getvobject(struct vop_getvobject_args *ap)
925 if (ap->a_vp->v_data == NULL)
928 lvp = NULLVPTOLOWERVP(ap->a_vp);
931 return (VOP_GETVOBJECT(lvp, ap->a_objpp));
935 * Global vfs data structures
937 struct vnodeopv_entry_desc null_vnodeop_entries[] = {
938 { &vop_default_desc, (vnodeopv_entry_t) null_bypass },
939 { &vop_access_desc, (vnodeopv_entry_t) null_access },
940 { &vop_createvobject_desc, (vnodeopv_entry_t) null_createvobject },
941 { &vop_destroyvobject_desc, (vnodeopv_entry_t) null_destroyvobject },
942 { &vop_getattr_desc, (vnodeopv_entry_t) null_getattr },
943 { &vop_getvobject_desc, (vnodeopv_entry_t) null_getvobject },
944 { &vop_inactive_desc, (vnodeopv_entry_t) null_inactive },
945 { &vop_islocked_desc, (vnodeopv_entry_t) null_islocked },
946 { &vop_lock_desc, (vnodeopv_entry_t) null_lock },
947 { &vop_lookup_desc, (vnodeopv_entry_t) null_lookup },
948 { &vop_open_desc, (vnodeopv_entry_t) null_open },
949 { &vop_print_desc, (vnodeopv_entry_t) null_print },
950 { &vop_reclaim_desc, (vnodeopv_entry_t) null_reclaim },
951 { &vop_rename_desc, (vnodeopv_entry_t) null_rename },
952 { &vop_setattr_desc, (vnodeopv_entry_t) null_setattr },
953 { &vop_unlock_desc, (vnodeopv_entry_t) null_unlock },
954 { &vop_revoke_desc, (vnodeopv_entry_t) null_revoke },
956 { &vop_nresolve_desc, (vnodeopv_entry_t) null_nresolve },
957 { &vop_ncreate_desc, (vnodeopv_entry_t) null_ncreate },
958 { &vop_nmkdir_desc, (vnodeopv_entry_t) null_nmkdir },
959 { &vop_nremove_desc, (vnodeopv_entry_t) null_nremove },
960 { &vop_nrmdir_desc, (vnodeopv_entry_t) null_nrmdir },
961 { &vop_nrename_desc, (vnodeopv_entry_t) null_nrename },