2 * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry.
3 * Copyright (c) 1992, 1993, 1994, 1995
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
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10 * modification, are permitted provided that the following conditions
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13 * notice, this list of conditions and the following disclaimer.
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17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
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34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * @(#)union_vnops.c 8.32 (Berkeley) 6/23/95
38 * $FreeBSD: src/sys/miscfs/union/union_vnops.c,v 1.72 1999/12/15 23:02:14 eivind Exp $
39 * $DragonFly: src/sys/vfs/union/union_vnops.c,v 1.23 2006/03/24 18:35:34 dillon Exp $
42 #include <sys/param.h>
43 #include <sys/systm.h>
45 #include <sys/fcntl.h>
47 #include <sys/kernel.h>
48 #include <sys/vnode.h>
49 #include <sys/mount.h>
50 #include <sys/namei.h>
51 #include <sys/malloc.h>
54 #include <sys/sysctl.h>
58 #include <vm/vnode_pager.h>
60 #include <vm/vm_page.h>
61 #include <vm/vm_object.h>
66 SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RW, &uniondebug, 0, "");
68 SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RD, &uniondebug, 0, "");
71 static int union_access (struct vop_access_args *ap);
72 static int union_advlock (struct vop_advlock_args *ap);
73 static int union_bmap (struct vop_bmap_args *ap);
74 static int union_close (struct vop_close_args *ap);
75 static int union_create (struct vop_old_create_args *ap);
76 static int union_fsync (struct vop_fsync_args *ap);
77 static int union_getattr (struct vop_getattr_args *ap);
78 static int union_inactive (struct vop_inactive_args *ap);
79 static int union_ioctl (struct vop_ioctl_args *ap);
80 static int union_lease (struct vop_lease_args *ap);
81 static int union_link (struct vop_old_link_args *ap);
82 static int union_lock (struct vop_lock_args *ap);
83 static int union_lookup (struct vop_old_lookup_args *ap);
84 static int union_lookup1 (struct vnode *udvp, struct vnode **dvp,
86 struct componentname *cnp);
87 static int union_mkdir (struct vop_old_mkdir_args *ap);
88 static int union_mknod (struct vop_old_mknod_args *ap);
89 static int union_mmap (struct vop_mmap_args *ap);
90 static int union_open (struct vop_open_args *ap);
91 static int union_pathconf (struct vop_pathconf_args *ap);
92 static int union_print (struct vop_print_args *ap);
93 static int union_read (struct vop_read_args *ap);
94 static int union_readdir (struct vop_readdir_args *ap);
95 static int union_readlink (struct vop_readlink_args *ap);
96 static int union_reclaim (struct vop_reclaim_args *ap);
97 static int union_remove (struct vop_old_remove_args *ap);
98 static int union_rename (struct vop_old_rename_args *ap);
99 static int union_revoke (struct vop_revoke_args *ap);
100 static int union_rmdir (struct vop_old_rmdir_args *ap);
101 static int union_poll (struct vop_poll_args *ap);
102 static int union_setattr (struct vop_setattr_args *ap);
103 static int union_strategy (struct vop_strategy_args *ap);
104 static int union_getpages (struct vop_getpages_args *ap);
105 static int union_putpages (struct vop_putpages_args *ap);
106 static int union_symlink (struct vop_old_symlink_args *ap);
107 static int union_unlock (struct vop_unlock_args *ap);
108 static int union_whiteout (struct vop_old_whiteout_args *ap);
109 static int union_write (struct vop_read_args *ap);
113 union_lock_upper(struct union_node *un, struct thread *td)
115 struct vnode *uppervp;
117 if ((uppervp = un->un_uppervp) != NULL) {
119 vn_lock(uppervp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, td);
121 KASSERT((uppervp == NULL || uppervp->v_usecount > 0), ("uppervp usecount is 0"));
127 union_unlock_upper(struct vnode *uppervp, struct thread *td)
134 union_lock_other(struct union_node *un, struct thread *td)
138 if (un->un_uppervp != NULL) {
139 vp = union_lock_upper(un, td);
140 } else if ((vp = un->un_lowervp) != NULL) {
142 vn_lock(vp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, td);
149 union_unlock_other(struct vnode *vp, struct thread *td)
157 * udvp must be exclusively locked on call and will remain
158 * exclusively locked on return. This is the mount point
159 * for out filesystem.
161 * dvp Our base directory, locked and referenced.
162 * The passed dvp will be dereferenced and unlocked on return
163 * and a new dvp will be returned which is locked and
164 * referenced in the same variable.
166 * vpp is filled in with the result if no error occured,
169 * If an error is returned, *vpp is set to NULLVP. If no
170 * error occurs, *vpp is returned with a reference and an
175 union_lookup1(struct vnode *udvp, struct vnode **pdvp, struct vnode **vpp,
176 struct componentname *cnp)
179 struct thread *td = cnp->cn_td;
180 struct vnode *dvp = *pdvp;
185 * If stepping up the directory tree, check for going
186 * back across the mount point, in which case do what
187 * lookup would do by stepping back down the mount
190 if (cnp->cn_flags & CNP_ISDOTDOT) {
191 while ((dvp != udvp) && (dvp->v_flag & VROOT)) {
193 * Don't do the NOCROSSMOUNT check
194 * at this level. By definition,
195 * union fs deals with namespaces, not
199 dvp = dvp->v_mount->mnt_vnodecovered;
202 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
207 * Set return dvp to be the upperdvp 'parent directory.
212 * If the VOP_LOOKUP call generates an error, tdvp is invalid and no
213 * changes will have been made to dvp, so we are set to return.
216 error = VOP_LOOKUP(dvp, &tdvp, cnp);
218 UDEBUG(("dvp %p error %d flags %lx\n", dvp, error, cnp->cn_flags));
224 * The parent directory will have been unlocked, unless lookup
225 * found the last component or if dvp == tdvp (tdvp must be locked).
227 * We want our dvp to remain locked and ref'd. We also want tdvp
228 * to remain locked and ref'd.
230 UDEBUG(("parentdir %p result %p flag %lx\n", dvp, tdvp, cnp->cn_flags));
233 if (dvp != tdvp && (cnp->cn_flags & CNP_XXXISLASTCN) == 0)
234 vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
238 * Lastly check if the current node is a mount point in
239 * which case walk up the mount hierarchy making sure not to
240 * bump into the root of the mount tree (ie. dvp != udvp).
242 * We use dvp as a temporary variable here, it is no longer related
243 * to the dvp above. However, we have to ensure that both *pdvp and
244 * tdvp are locked on return.
250 (dvp->v_type == VDIR) &&
251 (mp = dvp->v_mountedhere)
255 if (vfs_busy(mp, 0, td))
262 error = VFS_ROOT(mp, &dvp);
267 vn_lock(*pdvp, LK_EXCLUSIVE | LK_RETRY, td);
279 * union_lookup(struct vnodeop_desc *a_desc, struct vnode *a_dvp,
280 * struct vnode **a_vpp, struct componentname *a_cnp)
283 union_lookup(struct vop_old_lookup_args *ap)
287 struct vnode *uppervp, *lowervp;
288 struct vnode *upperdvp, *lowerdvp;
289 struct vnode *dvp = ap->a_dvp; /* starting dir */
290 struct union_node *dun = VTOUNION(dvp); /* associated union node */
291 struct componentname *cnp = ap->a_cnp;
292 struct thread *td = cnp->cn_td;
293 int lockparent = cnp->cn_flags & CNP_LOCKPARENT;
294 struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
295 struct ucred *saved_cred = NULL;
302 * Disallow write attemps to the filesystem mounted read-only.
304 if ((dvp->v_mount->mnt_flag & MNT_RDONLY) &&
305 (cnp->cn_nameiop == NAMEI_DELETE || cnp->cn_nameiop == NAMEI_RENAME)) {
310 * For any lookup's we do, always return with the parent locked
312 cnp->cn_flags |= CNP_LOCKPARENT;
314 lowerdvp = dun->un_lowervp;
323 * Get a private lock on uppervp and a reference, effectively
324 * taking it out of the union_node's control.
326 * We must lock upperdvp while holding our lock on dvp
327 * to avoid a deadlock.
329 upperdvp = union_lock_upper(dun, td);
332 * do the lookup in the upper level.
333 * if that level comsumes additional pathnames,
334 * then assume that something special is going
335 * on and just return that vnode.
337 if (upperdvp != NULLVP) {
339 * We do not have to worry about the DOTDOT case, we've
340 * already unlocked dvp.
342 UDEBUG(("A %p\n", upperdvp));
345 * Do the lookup. We must supply a locked and referenced
346 * upperdvp to the function and will get a new locked and
347 * referenced upperdvp back with the old having been
350 * If an error is returned, uppervp will be NULLVP. If no
351 * error occurs, uppervp will be the locked and referenced
352 * return vnode or possibly NULL, depending on what is being
353 * requested. It is possible that the returned uppervp
354 * will be the same as upperdvp.
356 uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp);
358 "uerror %d upperdvp %p %d/%d, uppervp %p ref=%d/lck=%d\n",
361 upperdvp->v_usecount,
362 VOP_ISLOCKED(upperdvp, NULL),
364 (uppervp ? uppervp->v_usecount : -99),
365 (uppervp ? VOP_ISLOCKED(uppervp, NULL) : -99)
369 * Disallow write attemps to the filesystem mounted read-only.
371 if (uerror == EJUSTRETURN &&
372 (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
373 (cnp->cn_nameiop == NAMEI_CREATE || cnp->cn_nameiop == NAMEI_RENAME)) {
379 * Special case. If cn_consume != 0 skip out. The result
380 * of the lookup is transfered to our return variable. If
381 * an error occured we have to throw away the results.
384 if (cnp->cn_consume != 0) {
385 if ((error = uerror) == 0) {
386 *ap->a_vpp = uppervp;
393 * Calculate whiteout, fall through
396 if (uerror == ENOENT || uerror == EJUSTRETURN) {
397 if (cnp->cn_flags & CNP_ISWHITEOUT) {
399 } else if (lowerdvp != NULLVP) {
402 terror = VOP_GETATTR(upperdvp, &va, cnp->cn_td);
403 if (terror == 0 && (va.va_flags & OPAQUE))
410 * in a similar way to the upper layer, do the lookup
411 * in the lower layer. this time, if there is some
412 * component magic going on, then vput whatever we got
413 * back from the upper layer and return the lower vnode
417 if (lowerdvp != NULLVP && !iswhiteout) {
420 UDEBUG(("B %p\n", lowerdvp));
423 * Force only LOOKUPs on the lower node, since
424 * we won't be making changes to it anyway.
426 nameiop = cnp->cn_nameiop;
427 cnp->cn_nameiop = NAMEI_LOOKUP;
428 if (um->um_op == UNMNT_BELOW) {
429 saved_cred = cnp->cn_cred;
430 cnp->cn_cred = um->um_cred;
434 * We shouldn't have to worry about locking interactions
435 * between the lower layer and our union layer (w.r.t.
436 * `..' processing) because we don't futz with lowervp
437 * locks in the union-node instantiation code path.
439 * union_lookup1() requires lowervp to be locked on entry,
440 * and it will be unlocked on return. The ref count will
441 * not change. On return lowervp doesn't represent anything
442 * to us so we NULL it out.
445 vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY, td);
446 lerror = union_lookup1(um->um_lowervp, &lowerdvp, &lowervp, cnp);
447 if (lowerdvp == lowervp)
451 lowerdvp = NULL; /* lowerdvp invalid after vput */
453 if (um->um_op == UNMNT_BELOW)
454 cnp->cn_cred = saved_cred;
455 cnp->cn_nameiop = nameiop;
457 if (cnp->cn_consume != 0 || lerror == EACCES) {
458 if ((error = lerror) == 0) {
459 *ap->a_vpp = lowervp;
465 UDEBUG(("C %p\n", lowerdvp));
466 if ((cnp->cn_flags & CNP_ISDOTDOT) && dun->un_pvp != NULLVP) {
467 if ((lowervp = LOWERVP(dun->un_pvp)) != NULL) {
469 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY, td);
476 * Ok. Now we have uerror, uppervp, upperdvp, lerror, and lowervp.
478 * 1. If both layers returned an error, select the upper layer.
480 * 2. If the upper layer faile and the bottom layer succeeded,
481 * two subcases occur:
483 * a. The bottom vnode is not a directory, in which case
484 * just return a new union vnode referencing an
485 * empty top layer and the existing bottom layer.
487 * b. The button vnode is a directory, in which case
488 * create a new directory in the top layer and
489 * and fall through to case 3.
491 * 3. If the top layer succeeded then return a new union
492 * vnode referencing whatever the new top layer and
493 * whatever the bottom layer returned.
497 if ((uerror != 0) && (lerror != 0)) {
503 if (uerror != 0 /* && (lerror == 0) */ ) {
504 if (lowervp->v_type == VDIR) { /* case 2b. */
505 KASSERT(uppervp == NULL, ("uppervp unexpectedly non-NULL"));
507 * oops, uppervp has a problem, we may have to shadow.
509 uerror = union_mkshadow(um, upperdvp, cnp, &uppervp);
518 * Must call union_allocvp with both the upper and lower vnodes
519 * referenced and the upper vnode locked. ap->a_vpp is returned
520 * referenced and locked. lowervp, uppervp, and upperdvp are
521 * absorbed by union_allocvp() whether it succeeds or fails.
523 * upperdvp is the parent directory of uppervp which may be
524 * different, depending on the path, from dvp->un_uppervp. That's
525 * why it is a separate argument. Note that it must be unlocked.
527 * dvp must be locked on entry to the call and will be locked on
531 if (uppervp && uppervp != upperdvp)
532 VOP_UNLOCK(uppervp, 0, td);
534 VOP_UNLOCK(lowervp, 0, td);
536 VOP_UNLOCK(upperdvp, 0, td);
538 error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
539 uppervp, lowervp, 1);
541 UDEBUG(("Create %p = %p %p refs=%d\n", *ap->a_vpp, uppervp, lowervp, (*ap->a_vpp) ? ((*ap->a_vpp)->v_usecount) : -99));
550 * - put away any extra junk laying around. Note that lowervp
551 * (if not NULL) will never be the same as *ap->a_vp and
552 * neither will uppervp, because when we set that state we
553 * NULL-out lowervp or uppervp. On the otherhand, upperdvp
554 * may match uppervp or *ap->a_vpp.
556 * - relock/unlock dvp if appropriate.
561 if (upperdvp == uppervp || upperdvp == *ap->a_vpp)
574 * Restore LOCKPARENT state
578 cnp->cn_flags &= ~CNP_LOCKPARENT;
580 UDEBUG(("Out %d vpp %p/%d lower %p upper %p\n", error, *ap->a_vpp,
581 ((*ap->a_vpp) ? (*ap->a_vpp)->v_usecount : -99),
585 * dvp lock state, determine whether to relock dvp. dvp is expected
586 * to be locked on return if:
588 * - there was an error (except not EJUSTRETURN), or
589 * - we hit the last component and lockparent is true
591 * dvp_is_locked is the current state of the dvp lock, not counting
592 * the possibility that *ap->a_vpp == dvp (in which case it is locked
593 * anyway). Note that *ap->a_vpp == dvp only if no error occured.
596 if (*ap->a_vpp != dvp) {
597 if ((error == 0 || error == EJUSTRETURN) && !lockparent) {
598 VOP_UNLOCK(dvp, 0, td);
607 if (cnp->cn_namelen == 1 &&
608 cnp->cn_nameptr[0] == '.' &&
610 panic("union_lookup returning . (%p) not same as startdir (%p)", ap->a_vpp, dvp);
620 * a_dvp is locked on entry and remains locked on return. a_vpp is returned
621 * locked if no error occurs, otherwise it is garbage.
623 * union_create(struct vnode *a_dvp, struct vnode **a_vpp,
624 * struct componentname *a_cnp, struct vattr *a_vap)
627 union_create(struct vop_old_create_args *ap)
629 struct union_node *dun = VTOUNION(ap->a_dvp);
630 struct componentname *cnp = ap->a_cnp;
631 struct thread *td = cnp->cn_td;
635 if ((dvp = union_lock_upper(dun, td)) != NULL) {
639 error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap);
641 mp = ap->a_dvp->v_mount;
642 VOP_UNLOCK(vp, 0, td);
643 UDEBUG(("ALLOCVP-1 FROM %p REFS %d\n", vp, vp->v_usecount));
644 error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP,
646 UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount));
648 union_unlock_upper(dvp, td);
654 * union_whiteout(struct vnode *a_dvp, struct componentname *a_cnp,
658 union_whiteout(struct vop_old_whiteout_args *ap)
660 struct union_node *un = VTOUNION(ap->a_dvp);
661 struct componentname *cnp = ap->a_cnp;
662 struct vnode *uppervp;
663 int error = EOPNOTSUPP;
665 if ((uppervp = union_lock_upper(un, cnp->cn_td)) != NULLVP) {
666 error = VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags);
667 union_unlock_upper(uppervp, cnp->cn_td);
675 * a_dvp is locked on entry and should remain locked on return.
676 * a_vpp is garbagre whether an error occurs or not.
678 * union_mknod(struct vnode *a_dvp, struct vnode **a_vpp,
679 * struct componentname *a_cnp, struct vattr *a_vap)
682 union_mknod(struct vop_old_mknod_args *ap)
684 struct union_node *dun = VTOUNION(ap->a_dvp);
685 struct componentname *cnp = ap->a_cnp;
689 if ((dvp = union_lock_upper(dun, cnp->cn_td)) != NULL) {
690 error = VOP_MKNOD(dvp, ap->a_vpp, cnp, ap->a_vap);
691 union_unlock_upper(dvp, cnp->cn_td);
699 * run open VOP. When opening the underlying vnode we have to mimic
700 * vn_open. What we *really* need to do to avoid screwups if the
701 * open semantics change is to call vn_open(). For example, ufs blows
702 * up if you open a file but do not vmio it prior to writing.
704 * union_open(struct vnodeop_desc *a_desc, struct vnode *a_vp, int a_mode,
705 * struct ucred *a_cred, struct thread *a_td)
708 union_open(struct vop_open_args *ap)
710 struct union_node *un = VTOUNION(ap->a_vp);
712 int mode = ap->a_mode;
713 struct ucred *cred = ap->a_cred;
714 struct thread *td = ap->a_td;
719 * If there is an existing upper vp then simply open that.
720 * The upper vp takes precedence over the lower vp. When opening
721 * a lower vp for writing copy it to the uppervp and then open the
724 * At the end of this section tvp will be left locked.
726 if ((tvp = union_lock_upper(un, td)) == NULLVP) {
728 * If the lower vnode is being opened for writing, then
729 * copy the file contents to the upper vnode and open that,
730 * otherwise can simply open the lower vnode.
732 tvp = un->un_lowervp;
733 if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) {
734 int docopy = !(mode & O_TRUNC);
735 error = union_copyup(un, docopy, cred, td);
736 tvp = union_lock_upper(un, td);
740 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, td);
746 * We are holding the correct vnode, open it
750 error = VOP_OPEN(tvp, mode, cred, NULL, td);
753 * Absolutely necessary or UFS will blowup
755 if (error == 0 && vn_canvmio(tvp) == TRUE) {
756 error = vfs_object_create(tvp, td);
760 * Release any locks held
764 union_unlock_upper(tvp, td);
774 * It is unclear whether a_vp is passed locked or unlocked. Whatever
775 * the case we do not change it.
777 * union_close(struct vnode *a_vp, int a_fflag, struct ucred *a_cred,
778 * struct thread *a_td)
781 union_close(struct vop_close_args *ap)
783 struct union_node *un = VTOUNION(ap->a_vp);
786 if ((vp = un->un_uppervp) == NULLVP) {
787 #ifdef UNION_DIAGNOSTIC
788 if (un->un_openl <= 0)
789 panic("union: un_openl cnt");
794 ap->a_head.a_ops = *vp->v_ops;
796 return(vop_close_ap(ap));
800 * Check access permission on the union vnode.
801 * The access check being enforced is to check
802 * against both the underlying vnode, and any
803 * copied vnode. This ensures that no additional
804 * file permissions are given away simply because
805 * the user caused an implicit file copy.
807 * union_access(struct vnodeop_desc *a_desc, struct vnode *a_vp, int a_mode,
808 * struct ucred *a_cred, struct thread *a_td)
811 union_access(struct vop_access_args *ap)
813 struct union_node *un = VTOUNION(ap->a_vp);
814 struct thread *td = ap->a_td;
819 * Disallow write attempts on filesystems mounted read-only.
821 if ((ap->a_mode & VWRITE) &&
822 (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) {
823 switch (ap->a_vp->v_type) {
833 if ((vp = union_lock_upper(un, td)) != NULLVP) {
834 ap->a_head.a_ops = *vp->v_ops;
836 error = vop_access_ap(ap);
837 union_unlock_upper(vp, td);
841 if ((vp = un->un_lowervp) != NULLVP) {
842 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
843 ap->a_head.a_ops = *vp->v_ops;
847 * Remove VWRITE from a_mode if our mount point is RW, because
848 * we want to allow writes and lowervp may be read-only.
850 if ((un->un_vnode->v_mount->mnt_flag & MNT_RDONLY) == 0)
851 ap->a_mode &= ~VWRITE;
853 error = vop_access_ap(ap);
855 struct union_mount *um;
857 um = MOUNTTOUNIONMOUNT(un->un_vnode->v_mount);
859 if (um->um_op == UNMNT_BELOW) {
860 ap->a_cred = um->um_cred;
861 error = vop_access_ap(ap);
864 VOP_UNLOCK(vp, 0, td);
870 * We handle getattr only to change the fsid and
873 * It's not clear whether VOP_GETATTR is to be
874 * called with the vnode locked or not. stat() calls
875 * it with (vp) locked, and fstat calls it with
878 * Because of this we cannot use our normal locking functions
879 * if we do not intend to lock the main a_vp node. At the moment
880 * we are running without any specific locking at all, but beware
881 * to any programmer that care must be taken if locking is added
884 * union_getattr(struct vnode *a_vp, struct vattr *a_vap,
885 * struct ucred *a_cred, struct thread *a_td)
888 union_getattr(struct vop_getattr_args *ap)
891 struct union_node *un = VTOUNION(ap->a_vp);
897 * Some programs walk the filesystem hierarchy by counting
898 * links to directories to avoid stat'ing all the time.
899 * This means the link count on directories needs to be "correct".
900 * The only way to do that is to call getattr on both layers
901 * and fix up the link count. The link count will not necessarily
902 * be accurate but will be large enough to defeat the tree walkers.
907 if ((vp = un->un_uppervp) != NULLVP) {
908 error = VOP_GETATTR(vp, vap, ap->a_td);
911 /* XXX isn't this dangerouso without a lock? */
912 union_newsize(ap->a_vp, vap->va_size, VNOVAL);
917 } else if (vp->v_type == VDIR && un->un_lowervp != NULLVP) {
925 error = VOP_GETATTR(vp, vap, ap->a_td);
928 /* XXX isn't this dangerous without a lock? */
929 union_newsize(ap->a_vp, VNOVAL, vap->va_size);
932 if ((vap != ap->a_vap) && (vap->va_type == VDIR))
933 ap->a_vap->va_nlink += vap->va_nlink;
938 * union_setattr(struct vnode *a_vp, struct vattr *a_vap,
939 * struct ucred *a_cred, struct thread *a_td)
942 union_setattr(struct vop_setattr_args *ap)
944 struct union_node *un = VTOUNION(ap->a_vp);
945 struct thread *td = ap->a_td;
946 struct vattr *vap = ap->a_vap;
947 struct vnode *uppervp;
951 * Disallow write attempts on filesystems mounted read-only.
953 if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) &&
954 (vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
955 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
956 vap->va_mtime.tv_sec != VNOVAL ||
957 vap->va_mode != (mode_t)VNOVAL)) {
962 * Handle case of truncating lower object to zero size,
963 * by creating a zero length upper object. This is to
964 * handle the case of open with O_TRUNC and O_CREAT.
966 if (un->un_uppervp == NULLVP && (un->un_lowervp->v_type == VREG)) {
967 error = union_copyup(un, (ap->a_vap->va_size != 0),
968 ap->a_cred, ap->a_td);
974 * Try to set attributes in upper layer,
975 * otherwise return read-only filesystem error.
978 if ((uppervp = union_lock_upper(un, td)) != NULLVP) {
979 error = VOP_SETATTR(un->un_uppervp, ap->a_vap,
980 ap->a_cred, ap->a_td);
981 if ((error == 0) && (ap->a_vap->va_size != VNOVAL))
982 union_newsize(ap->a_vp, ap->a_vap->va_size, VNOVAL);
983 union_unlock_upper(uppervp, td);
993 union_getpages(struct vop_getpages_args *ap)
997 r = vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
998 ap->a_count, ap->a_reqpage);
1007 union_putpages(struct vop_putpages_args *ap)
1011 r = vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
1012 ap->a_sync, ap->a_rtvals);
1017 * union_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
1018 * struct ucred *a_cred)
1021 union_read(struct vop_read_args *ap)
1023 struct union_node *un = VTOUNION(ap->a_vp);
1024 struct thread *td = ap->a_uio->uio_td;
1028 uvp = union_lock_other(un, td);
1029 KASSERT(uvp != NULL, ("union_read: backing vnode missing!"));
1031 if (ap->a_vp->v_flag & VOBJBUF)
1032 union_vm_coherency(ap->a_vp, ap->a_uio, 0);
1034 error = VOP_READ(uvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
1035 union_unlock_other(uvp, td);
1039 * perhaps the size of the underlying object has changed under
1040 * our feet. take advantage of the offset information present
1041 * in the uio structure.
1044 struct union_node *un = VTOUNION(ap->a_vp);
1045 off_t cur = ap->a_uio->uio_offset;
1047 if (uvp == un->un_uppervp) {
1048 if (cur > un->un_uppersz)
1049 union_newsize(ap->a_vp, cur, VNOVAL);
1051 if (cur > un->un_lowersz)
1052 union_newsize(ap->a_vp, VNOVAL, cur);
1059 * union_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
1060 * struct ucred *a_cred)
1063 union_write(struct vop_read_args *ap)
1065 struct union_node *un = VTOUNION(ap->a_vp);
1066 struct thread *td = ap->a_uio->uio_td;
1067 struct vnode *uppervp;
1070 if ((uppervp = union_lock_upper(un, td)) == NULLVP)
1071 panic("union: missing upper layer in write");
1074 * Since our VM pages are associated with our vnode rather then
1075 * the real vnode, and since we do not run our reads and writes
1076 * through our own VM cache, we have a VM/VFS coherency problem.
1077 * We solve them by invalidating or flushing the associated VM
1078 * pages prior to allowing a normal read or write to occur.
1080 * VM-backed writes (UIO_NOCOPY) have to be converted to normal
1081 * writes because we are not cache-coherent. Normal writes need
1082 * to be made coherent with our VM-backing store, which we do by
1083 * first flushing any dirty VM pages associated with the write
1084 * range, and then destroying any clean VM pages associated with
1088 if (ap->a_uio->uio_segflg == UIO_NOCOPY) {
1089 ap->a_uio->uio_segflg = UIO_SYSSPACE;
1090 } else if (ap->a_vp->v_flag & VOBJBUF) {
1091 union_vm_coherency(ap->a_vp, ap->a_uio, 1);
1094 error = VOP_WRITE(uppervp, ap->a_uio, ap->a_ioflag, ap->a_cred);
1097 * the size of the underlying object may be changed by the
1101 off_t cur = ap->a_uio->uio_offset;
1103 if (cur > un->un_uppersz)
1104 union_newsize(ap->a_vp, cur, VNOVAL);
1106 union_unlock_upper(uppervp, td);
1111 * union_lease(struct vnode *a_vp, struct thread *a_td, struct ucred *a_cred,
1115 union_lease(struct vop_lease_args *ap)
1117 struct vnode *ovp = OTHERVP(ap->a_vp);
1119 ap->a_head.a_ops = *ovp->v_ops;
1121 return (vop_lease_ap(ap));
1125 * union_ioctl(struct vnode *a_vp, int a_command, caddr_t a_data, int a_fflag,
1126 * struct ucred *a_cred, struct thread *a_td)
1129 union_ioctl(struct vop_ioctl_args *ap)
1131 struct vnode *ovp = OTHERVP(ap->a_vp);
1133 ap->a_head.a_ops = *ovp->v_ops;
1135 return(vop_ioctl_ap(ap));
1139 * union_poll(struct vnode *a_vp, int a_events, struct ucred *a_cred,
1140 * struct thread *a_td)
1143 union_poll(struct vop_poll_args *ap)
1145 struct vnode *ovp = OTHERVP(ap->a_vp);
1147 ap->a_head.a_ops = *ovp->v_ops;
1149 return(vop_poll_ap(ap));
1153 * union_revoke(struct vnode *a_vp, int a_flags, struct thread *a_td)
1156 union_revoke(struct vop_revoke_args *ap)
1158 struct vnode *vp = ap->a_vp;
1161 if ((vx = UPPERVP(vp)) != NULL) {
1162 if (vx_get(vx) == 0) {
1163 VOP_REVOKE(vx, ap->a_flags);
1167 if ((vx = LOWERVP(vp)) != NULL) {
1168 if (vx_get(vx) == 0) {
1169 VOP_REVOKE(vx, ap->a_flags);
1178 * union_mmap(struct vnode *a_vp, int a_fflags, struct ucred *a_cred,
1179 * struct thread *a_td)
1182 union_mmap(struct vop_mmap_args *ap)
1184 struct vnode *ovp = OTHERVP(ap->a_vp);
1186 ap->a_head.a_ops = *ovp->v_ops;
1188 return (vop_mmap_ap(ap));
1192 * union_fsync(struct vnode *a_vp, struct ucred *a_cred, int a_waitfor,
1193 * struct thread *a_td)
1196 union_fsync(struct vop_fsync_args *ap)
1199 struct thread *td = ap->a_td;
1200 struct vnode *targetvp;
1201 struct union_node *un = VTOUNION(ap->a_vp);
1203 if ((targetvp = union_lock_other(un, td)) != NULLVP) {
1204 error = VOP_FSYNC(targetvp, ap->a_waitfor, td);
1205 union_unlock_other(targetvp, td);
1214 * Remove the specified cnp. The dvp and vp are passed to us locked
1215 * and must remain locked on return.
1217 * union_remove(struct vnode *a_dvp, struct vnode *a_vp,
1218 * struct componentname *a_cnp)
1221 union_remove(struct vop_old_remove_args *ap)
1223 struct union_node *dun = VTOUNION(ap->a_dvp);
1224 struct union_node *un = VTOUNION(ap->a_vp);
1225 struct componentname *cnp = ap->a_cnp;
1226 struct thread *td = cnp->cn_td;
1227 struct vnode *uppervp;
1228 struct vnode *upperdvp;
1231 if ((upperdvp = union_lock_upper(dun, td)) == NULLVP)
1232 panic("union remove: null upper vnode");
1234 if ((uppervp = union_lock_upper(un, td)) != NULLVP) {
1235 if (union_dowhiteout(un, cnp->cn_cred, td))
1236 cnp->cn_flags |= CNP_DOWHITEOUT;
1237 error = VOP_REMOVE(upperdvp, uppervp, cnp);
1241 union_removed_upper(un);
1243 union_unlock_upper(uppervp, td);
1245 error = union_mkwhiteout(
1246 MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount),
1247 upperdvp, ap->a_cnp, un->un_path);
1249 union_unlock_upper(upperdvp, td);
1256 * tdvp will be locked on entry, vp will not be locked on entry.
1257 * tdvp should remain locked on return and vp should remain unlocked
1260 * union_link(struct vnode *a_tdvp, struct vnode *a_vp,
1261 * struct componentname *a_cnp)
1264 union_link(struct vop_old_link_args *ap)
1266 struct componentname *cnp = ap->a_cnp;
1267 struct thread *td = cnp->cn_td;
1268 struct union_node *dun = VTOUNION(ap->a_tdvp);
1273 if (ap->a_tdvp->v_ops != ap->a_vp->v_ops) {
1276 struct union_node *tun = VTOUNION(ap->a_vp);
1278 if (tun->un_uppervp == NULLVP) {
1279 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td);
1281 if (dun->un_uppervp == tun->un_dirvp) {
1282 if (dun->un_flags & UN_ULOCK) {
1283 dun->un_flags &= ~UN_ULOCK;
1284 VOP_UNLOCK(dun->un_uppervp, 0, td);
1288 error = union_copyup(tun, 1, cnp->cn_cred, td);
1290 if (dun->un_uppervp == tun->un_dirvp) {
1291 vn_lock(dun->un_uppervp,
1292 LK_EXCLUSIVE | LK_RETRY, td);
1293 dun->un_flags |= UN_ULOCK;
1296 VOP_UNLOCK(ap->a_vp, 0, td);
1298 vp = tun->un_uppervp;
1305 * Make sure upper is locked, then unlock the union directory we were
1306 * called with to avoid a deadlock while we are calling VOP_LINK on
1307 * the upper (with tdvp locked and vp not locked). Our ap->a_tdvp
1308 * is expected to be locked on return.
1311 if ((tdvp = union_lock_upper(dun, td)) == NULLVP)
1314 VOP_UNLOCK(ap->a_tdvp, 0, td); /* unlock calling node */
1315 error = VOP_LINK(tdvp, vp, cnp); /* call link on upper */
1318 * We have to unlock tdvp prior to relocking our calling node in
1319 * order to avoid a deadlock.
1321 union_unlock_upper(tdvp, td);
1322 vn_lock(ap->a_tdvp, LK_EXCLUSIVE | LK_RETRY, td);
1327 * union_rename(struct vnode *a_fdvp, struct vnode *a_fvp,
1328 * struct componentname *a_fcnp, struct vnode *a_tdvp,
1329 * struct vnode *a_tvp, struct componentname *a_tcnp)
1332 union_rename(struct vop_old_rename_args *ap)
1335 struct vnode *fdvp = ap->a_fdvp;
1336 struct vnode *fvp = ap->a_fvp;
1337 struct vnode *tdvp = ap->a_tdvp;
1338 struct vnode *tvp = ap->a_tvp;
1341 * Figure out what fdvp to pass to our upper or lower vnode. If we
1342 * replace the fdvp, release the original one and ref the new one.
1345 if (fdvp->v_tag == VT_UNION) { /* always true */
1346 struct union_node *un = VTOUNION(fdvp);
1347 if (un->un_uppervp == NULLVP) {
1349 * this should never happen in normal
1350 * operation but might if there was
1351 * a problem creating the top-level shadow
1357 fdvp = un->un_uppervp;
1363 * Figure out what fvp to pass to our upper or lower vnode. If we
1364 * replace the fvp, release the original one and ref the new one.
1367 if (fvp->v_tag == VT_UNION) { /* always true */
1368 struct union_node *un = VTOUNION(fvp);
1370 struct union_mount *um = MOUNTTOUNIONMOUNT(fvp->v_mount);
1373 if (un->un_uppervp == NULLVP) {
1374 switch(fvp->v_type) {
1376 vn_lock(un->un_vnode, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_td);
1377 error = union_copyup(un, 1, ap->a_fcnp->cn_cred, ap->a_fcnp->cn_td);
1378 VOP_UNLOCK(un->un_vnode, 0, ap->a_fcnp->cn_td);
1386 * There is only one way to rename a directory
1387 * based in the lowervp, and that is to copy
1388 * the entire directory hierarchy. Otherwise
1389 * it would not last across a reboot.
1394 vn_lock(fdvp, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_td);
1395 error = union_mkshadow(um, fdvp,
1396 ap->a_fcnp, &un->un_uppervp);
1397 VOP_UNLOCK(fdvp, 0, ap->a_fcnp->cn_td);
1399 VOP_UNLOCK(un->un_uppervp, 0, ap->a_fcnp->cn_td);
1410 if (un->un_lowervp != NULLVP)
1411 ap->a_fcnp->cn_flags |= CNP_DOWHITEOUT;
1412 fvp = un->un_uppervp;
1418 * Figure out what tdvp (destination directory) to pass to the
1419 * lower level. If we replace it with uppervp, we need to vput the
1420 * old one. The exclusive lock is transfered to what we will pass
1421 * down in the VOP_RENAME and we replace uppervp with a simple
1425 if (tdvp->v_tag == VT_UNION) {
1426 struct union_node *un = VTOUNION(tdvp);
1428 if (un->un_uppervp == NULLVP) {
1430 * this should never happen in normal
1431 * operation but might if there was
1432 * a problem creating the top-level shadow
1440 * new tdvp is a lock and reference on uppervp, put away
1443 tdvp = union_lock_upper(un, ap->a_tcnp->cn_td);
1448 * Figure out what tvp (destination file) to pass to the
1451 * If the uppervp file does not exist put away the (wrong)
1452 * file and change tvp to NULL.
1455 if (tvp != NULLVP && tvp->v_tag == VT_UNION) {
1456 struct union_node *un = VTOUNION(tvp);
1458 tvp = union_lock_upper(un, ap->a_tcnp->cn_td);
1460 /* note: tvp may be NULL */
1464 * VOP_RENAME releases/vputs prior to returning, so we have no
1468 return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp));
1471 * Error. We still have to release / vput the various elements.
1479 if (tvp != NULLVP) {
1489 * union_mkdir(struct vnode *a_dvp, struct vnode **a_vpp,
1490 * struct componentname *a_cnp, struct vattr *a_vap)
1493 union_mkdir(struct vop_old_mkdir_args *ap)
1495 struct union_node *dun = VTOUNION(ap->a_dvp);
1496 struct componentname *cnp = ap->a_cnp;
1497 struct thread *td = cnp->cn_td;
1498 struct vnode *upperdvp;
1501 if ((upperdvp = union_lock_upper(dun, td)) != NULLVP) {
1504 error = VOP_MKDIR(upperdvp, &vp, cnp, ap->a_vap);
1505 union_unlock_upper(upperdvp, td);
1508 VOP_UNLOCK(vp, 0, td);
1509 UDEBUG(("ALLOCVP-2 FROM %p REFS %d\n", vp, vp->v_usecount));
1510 error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount,
1511 ap->a_dvp, NULLVP, cnp, vp, NULLVP, 1);
1512 UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount));
1519 * union_rmdir(struct vnode *a_dvp, struct vnode *a_vp,
1520 * struct componentname *a_cnp)
1523 union_rmdir(struct vop_old_rmdir_args *ap)
1525 struct union_node *dun = VTOUNION(ap->a_dvp);
1526 struct union_node *un = VTOUNION(ap->a_vp);
1527 struct componentname *cnp = ap->a_cnp;
1528 struct thread *td = cnp->cn_td;
1529 struct vnode *upperdvp;
1530 struct vnode *uppervp;
1533 if ((upperdvp = union_lock_upper(dun, td)) == NULLVP)
1534 panic("union rmdir: null upper vnode");
1536 if ((uppervp = union_lock_upper(un, td)) != NULLVP) {
1537 if (union_dowhiteout(un, cnp->cn_cred, td))
1538 cnp->cn_flags |= CNP_DOWHITEOUT;
1539 error = VOP_RMDIR(upperdvp, uppervp, ap->a_cnp);
1540 union_unlock_upper(uppervp, td);
1542 error = union_mkwhiteout(
1543 MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount),
1544 dun->un_uppervp, ap->a_cnp, un->un_path);
1546 union_unlock_upper(upperdvp, td);
1553 * dvp is locked on entry and remains locked on return. a_vpp is garbage
1556 * union_symlink(struct vnode *a_dvp, struct vnode **a_vpp,
1557 * struct componentname *a_cnp, struct vattr *a_vap,
1561 union_symlink(struct vop_old_symlink_args *ap)
1563 struct union_node *dun = VTOUNION(ap->a_dvp);
1564 struct componentname *cnp = ap->a_cnp;
1565 struct thread *td = cnp->cn_td;
1569 if ((dvp = union_lock_upper(dun, td)) != NULLVP) {
1570 error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap,
1572 union_unlock_upper(dvp, td);
1578 * union_readdir works in concert with getdirentries and
1579 * readdir(3) to provide a list of entries in the unioned
1580 * directories. getdirentries is responsible for walking
1581 * down the union stack. readdir(3) is responsible for
1582 * eliminating duplicate names from the returned data stream.
1584 * union_readdir(struct vnode *a_vp, struct uio *a_uio, struct ucred *a_cred,
1585 * int *a_eofflag, u_long *a_cookies, int a_ncookies)
1588 union_readdir(struct vop_readdir_args *ap)
1590 struct union_node *un = VTOUNION(ap->a_vp);
1591 struct thread *td = ap->a_uio->uio_td;
1595 if ((uvp = union_lock_upper(un, td)) != NULLVP) {
1596 ap->a_head.a_ops = *uvp->v_ops;
1598 error = vop_readdir_ap(ap);
1599 union_unlock_upper(uvp, td);
1605 * union_readlink(struct vnode *a_vp, struct uio *a_uio, struct ucred *a_cred)
1608 union_readlink(struct vop_readlink_args *ap)
1611 struct union_node *un = VTOUNION(ap->a_vp);
1612 struct uio *uio = ap->a_uio;
1613 struct thread *td = uio->uio_td;
1616 vp = union_lock_other(un, td);
1617 KASSERT(vp != NULL, ("union_readlink: backing vnode missing!"));
1619 ap->a_head.a_ops = *vp->v_ops;
1621 error = vop_readlink_ap(ap);
1622 union_unlock_other(vp, td);
1630 * Called with the vnode locked. We are expected to unlock the vnode.
1632 * union_inactive(struct vnode *a_vp, struct thread *a_td)
1635 union_inactive(struct vop_inactive_args *ap)
1637 struct vnode *vp = ap->a_vp;
1638 /*struct thread *td = ap->a_td;*/
1639 struct union_node *un = VTOUNION(vp);
1643 * Do nothing (and _don't_ bypass).
1644 * Wait to vrele lowervp until reclaim,
1645 * so that until then our union_node is in the
1646 * cache and reusable.
1648 * NEEDSWORK: Someday, consider inactive'ing
1649 * the lowervp and then trying to reactivate it
1650 * with capabilities (v_id)
1651 * like they do in the name lookup cache code.
1652 * That's too much work for now.
1655 if (un->un_dircache != 0) {
1656 for (vpp = un->un_dircache; *vpp != NULLVP; vpp++)
1658 free (un->un_dircache, M_TEMP);
1659 un->un_dircache = 0;
1663 if ((un->un_flags & UN_ULOCK) && un->un_uppervp) {
1664 un->un_flags &= ~UN_ULOCK;
1665 VOP_UNLOCK(un->un_uppervp, 0, td);
1669 if ((un->un_flags & UN_CACHED) == 0)
1676 * union_reclaim(struct vnode *a_vp)
1679 union_reclaim(struct vop_reclaim_args *ap)
1681 union_freevp(ap->a_vp);
1687 union_lock(struct vop_lock_args *ap)
1690 struct vnode *vp = ap->a_vp;
1691 struct thread *td = ap->a_td;
1692 int flags = ap->a_flags;
1693 struct union_node *un;
1697 error = vop_stdlock(ap);
1703 * Lock the upper if it exists and this is an exclusive lock
1706 if (un->un_uppervp != NULLVP &&
1707 (flags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
1708 if ((un->un_flags & UN_ULOCK) == 0 && vp->v_usecount) {
1709 error = vn_lock(un->un_uppervp, flags, td);
1711 struct vop_unlock_args uap = { 0 };
1712 uap.a_vp = ap->a_vp;
1713 uap.a_flags = ap->a_flags;
1714 uap.a_td = ap->a_td;
1715 vop_stdunlock(&uap);
1718 un->un_flags |= UN_ULOCK;
1729 * Unlock our union node. This also unlocks uppervp.
1731 * union_unlock(struct vnode *a_vp, int a_flags, struct thread *a_td)
1734 union_unlock(struct vop_unlock_args *ap)
1738 struct union_node *un = VTOUNION(ap->a_vp);
1740 KASSERT((un->un_uppervp == NULL || un->un_uppervp->v_usecount > 0), ("uppervp usecount is 0"));
1743 error = vop_stdunlock(ap);
1747 * If no exclusive locks remain and we are holding an uppervp lock,
1748 * remove the uppervp lock.
1751 if ((un->un_flags & UN_ULOCK) &&
1752 lockstatus(&un->un_lock, NULL) != LK_EXCLUSIVE) {
1753 un->un_flags &= ~UN_ULOCK;
1754 VOP_UNLOCK(un->un_uppervp, LK_EXCLUSIVE, td);
1763 * There isn't much we can do. We cannot push through to the real vnode
1764 * to get to the underlying device because this will bypass data
1765 * cached by the real vnode.
1767 * For some reason we cannot return the 'real' vnode either, it seems
1768 * to blow up memory maps.
1770 * union_bmap(struct vnode *a_vp, off_t a_loffset, struct vnode **a_vpp,
1771 * off_t *a_doffsetp, int *a_runp, int *a_runb)
1774 union_bmap(struct vop_bmap_args *ap)
1780 * union_print(struct vnode *a_vp)
1783 union_print(struct vop_print_args *ap)
1785 struct vnode *vp = ap->a_vp;
1787 printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n",
1788 vp, UPPERVP(vp), LOWERVP(vp));
1789 if (UPPERVP(vp) != NULLVP)
1790 vprint("union: upper", UPPERVP(vp));
1791 if (LOWERVP(vp) != NULLVP)
1792 vprint("union: lower", LOWERVP(vp));
1798 * union_pathconf(struct vnode *a_vp, int a_name, int *a_retval)
1801 union_pathconf(struct vop_pathconf_args *ap)
1804 struct thread *td = curthread; /* XXX */
1805 struct union_node *un = VTOUNION(ap->a_vp);
1808 vp = union_lock_other(un, td);
1809 KASSERT(vp != NULL, ("union_pathconf: backing vnode missing!"));
1811 ap->a_head.a_ops = *vp->v_ops;
1813 error = vop_pathconf_ap(ap);
1814 union_unlock_other(vp, td);
1820 * union_advlock(struct vnode *a_vp, caddr_t a_id, int a_op,
1821 * struct flock *a_fl, int a_flags)
1824 union_advlock(struct vop_advlock_args *ap)
1826 struct vnode *ovp = OTHERVP(ap->a_vp);
1828 ap->a_head.a_ops = *ovp->v_ops;
1830 return (vop_advlock_ap(ap));
1835 * XXX - vop_strategy must be hand coded because it has no
1836 * YYY - and it is not coherent with anything
1838 * vnode in its arguments.
1839 * This goes away with a merged VM/buffer cache.
1841 * union_strategy(struct vnode *a_vp, struct bio *a_bio)
1844 union_strategy(struct vop_strategy_args *ap)
1846 struct bio *bio = ap->a_bio;
1847 struct buf *bp = bio->bio_buf;
1848 struct vnode *othervp = OTHERVP(ap->a_vp);
1851 if (othervp == NULLVP)
1852 panic("union_strategy: nil vp");
1853 if (((bp->b_flags & B_READ) == 0) && (othervp == LOWERVP(ap->a_vp)))
1854 panic("union_strategy: writing to lowervp");
1856 return (vn_strategy(othervp, bio));
1860 * Global vfs data structures
1862 struct vnodeopv_entry_desc union_vnodeop_entries[] = {
1863 { &vop_default_desc, vop_defaultop },
1864 { &vop_access_desc, (vnodeopv_entry_t) union_access },
1865 { &vop_advlock_desc, (vnodeopv_entry_t) union_advlock },
1866 { &vop_bmap_desc, (vnodeopv_entry_t) union_bmap },
1867 { &vop_close_desc, (vnodeopv_entry_t) union_close },
1868 { &vop_old_create_desc, (vnodeopv_entry_t) union_create },
1869 { &vop_fsync_desc, (vnodeopv_entry_t) union_fsync },
1870 { &vop_getpages_desc, (vnodeopv_entry_t) union_getpages },
1871 { &vop_putpages_desc, (vnodeopv_entry_t) union_putpages },
1872 { &vop_getattr_desc, (vnodeopv_entry_t) union_getattr },
1873 { &vop_inactive_desc, (vnodeopv_entry_t) union_inactive },
1874 { &vop_ioctl_desc, (vnodeopv_entry_t) union_ioctl },
1875 { &vop_islocked_desc, vop_stdislocked },
1876 { &vop_lease_desc, (vnodeopv_entry_t) union_lease },
1877 { &vop_old_link_desc, (vnodeopv_entry_t) union_link },
1878 { &vop_lock_desc, (vnodeopv_entry_t) union_lock },
1879 { &vop_old_lookup_desc, (vnodeopv_entry_t) union_lookup },
1880 { &vop_old_mkdir_desc, (vnodeopv_entry_t) union_mkdir },
1881 { &vop_old_mknod_desc, (vnodeopv_entry_t) union_mknod },
1882 { &vop_mmap_desc, (vnodeopv_entry_t) union_mmap },
1883 { &vop_open_desc, (vnodeopv_entry_t) union_open },
1884 { &vop_pathconf_desc, (vnodeopv_entry_t) union_pathconf },
1885 { &vop_poll_desc, (vnodeopv_entry_t) union_poll },
1886 { &vop_print_desc, (vnodeopv_entry_t) union_print },
1887 { &vop_read_desc, (vnodeopv_entry_t) union_read },
1888 { &vop_readdir_desc, (vnodeopv_entry_t) union_readdir },
1889 { &vop_readlink_desc, (vnodeopv_entry_t) union_readlink },
1890 { &vop_reclaim_desc, (vnodeopv_entry_t) union_reclaim },
1891 { &vop_old_remove_desc, (vnodeopv_entry_t) union_remove },
1892 { &vop_old_rename_desc, (vnodeopv_entry_t) union_rename },
1893 { &vop_revoke_desc, (vnodeopv_entry_t) union_revoke },
1894 { &vop_old_rmdir_desc, (vnodeopv_entry_t) union_rmdir },
1895 { &vop_setattr_desc, (vnodeopv_entry_t) union_setattr },
1896 { &vop_strategy_desc, (vnodeopv_entry_t) union_strategy },
1897 { &vop_old_symlink_desc, (vnodeopv_entry_t) union_symlink },
1898 { &vop_unlock_desc, (vnodeopv_entry_t) union_unlock },
1899 { &vop_old_whiteout_desc, (vnodeopv_entry_t) union_whiteout },
1900 { &vop_write_desc, (vnodeopv_entry_t) union_write },