/* * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry. * Copyright (c) 1992, 1993, 1994, 1995 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)union_vnops.c 8.32 (Berkeley) 6/23/95 * $FreeBSD$ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include int uniondebug = 0; #if UDEBUG_ENABLED SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RW, &uniondebug, 0, ""); #else SYSCTL_INT(_vfs, OID_AUTO, uniondebug, CTLFLAG_RD, &uniondebug, 0, ""); #endif static int union_abortop __P((struct vop_abortop_args *ap)); static int union_access __P((struct vop_access_args *ap)); static int union_advlock __P((struct vop_advlock_args *ap)); static int union_bmap __P((struct vop_bmap_args *ap)); static int union_close __P((struct vop_close_args *ap)); static int union_create __P((struct vop_create_args *ap)); static int union_fsync __P((struct vop_fsync_args *ap)); static int union_getattr __P((struct vop_getattr_args *ap)); static int union_inactive __P((struct vop_inactive_args *ap)); static int union_ioctl __P((struct vop_ioctl_args *ap)); static int union_lease __P((struct vop_lease_args *ap)); static int union_link __P((struct vop_link_args *ap)); static int union_lock __P((struct vop_lock_args *ap)); static int union_lookup __P((struct vop_lookup_args *ap)); static int union_lookup1 __P((struct vnode *udvp, struct vnode **dvp, struct vnode **vpp, struct componentname *cnp)); static int union_mkdir __P((struct vop_mkdir_args *ap)); static int union_mknod __P((struct vop_mknod_args *ap)); static int union_mmap __P((struct vop_mmap_args *ap)); static int union_open __P((struct vop_open_args *ap)); static int union_pathconf __P((struct vop_pathconf_args *ap)); static int union_print __P((struct vop_print_args *ap)); static int union_read __P((struct vop_read_args *ap)); static int union_readdir __P((struct vop_readdir_args *ap)); static int union_readlink __P((struct vop_readlink_args *ap)); static int union_reclaim __P((struct vop_reclaim_args *ap)); static int union_remove __P((struct vop_remove_args *ap)); static int union_rename __P((struct vop_rename_args *ap)); static int union_revoke __P((struct vop_revoke_args *ap)); static int union_rmdir __P((struct vop_rmdir_args *ap)); static int union_poll __P((struct vop_poll_args *ap)); static int union_setattr __P((struct vop_setattr_args *ap)); static int union_strategy __P((struct vop_strategy_args *ap)); static int union_getpages __P((struct vop_getpages_args *ap)); static int union_putpages __P((struct vop_putpages_args *ap)); static int union_symlink __P((struct vop_symlink_args *ap)); static int union_unlock __P((struct vop_unlock_args *ap)); static int union_whiteout __P((struct vop_whiteout_args *ap)); static int union_write __P((struct vop_read_args *ap)); static __inline struct vnode * union_lock_upper(struct union_node *un, struct proc *p) { struct vnode *uppervp; if ((uppervp = un->un_uppervp) != NULL) { VREF(uppervp); vn_lock(uppervp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, p); } KASSERT((uppervp == NULL || uppervp->v_usecount > 0), ("uppervp usecount is 0")); return(uppervp); } static __inline void union_unlock_upper(struct vnode *uppervp, struct proc *p) { vput(uppervp); } static __inline struct vnode * union_lock_other(struct union_node *un, struct proc *p) { struct vnode *vp; if (un->un_uppervp != NULL) { vp = union_lock_upper(un, p); } else if ((vp = un->un_lowervp) != NULL) { VREF(vp); vn_lock(vp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY, p); } return(vp); } static __inline void union_unlock_other(struct vnode *vp, struct proc *p) { vput(vp); } /* * union_lookup: * * udvp must be exclusively locked on call and will remain * exclusively locked on return. This is the mount point * for out filesystem. * * dvp Our base directory, locked and referenced. * The passed dvp will be dereferenced and unlocked on return * and a new dvp will be returned which is locked and * referenced in the same variable. * * vpp is filled in with the result if no error occured, * locked and ref'd. * * If an error is returned, *vpp is set to NULLVP. If no * error occurs, *vpp is returned with a reference and an * exclusive lock. */ static int union_lookup1(udvp, pdvp, vpp, cnp) struct vnode *udvp; struct vnode **pdvp; struct vnode **vpp; struct componentname *cnp; { int error; struct proc *p = cnp->cn_proc; struct vnode *dvp = *pdvp; struct vnode *tdvp; struct mount *mp; /* * If stepping up the directory tree, check for going * back across the mount point, in which case do what * lookup would do by stepping back down the mount * hierarchy. */ if (cnp->cn_flags & ISDOTDOT) { while ((dvp != udvp) && (dvp->v_flag & VROOT)) { /* * Don't do the NOCROSSMOUNT check * at this level. By definition, * union fs deals with namespaces, not * filesystems. */ tdvp = dvp; dvp = dvp->v_mount->mnt_vnodecovered; VREF(dvp); vput(tdvp); vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); } } /* * Set return dvp to be the upperdvp 'parent directory. */ *pdvp = dvp; /* * If the VOP_LOOKUP call generates an error, tdvp is invalid and no * changes will have been made to dvp, so we are set to return. */ error = VOP_LOOKUP(dvp, &tdvp, cnp); if (error) { UDEBUG(("dvp %p error %d flags %lx\n", dvp, error, cnp->cn_flags)); *vpp = NULL; return (error); } /* * The parent directory will have been unlocked, unless lookup * found the last component or if dvp == tdvp (tdvp must be locked). * * We want our dvp to remain locked and ref'd. We also want tdvp * to remain locked and ref'd. */ UDEBUG(("parentdir %p result %p flag %lx\n", dvp, tdvp, cnp->cn_flags)); if (dvp != tdvp && (cnp->cn_flags & ISLASTCN) == 0) vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p); /* * Lastly check if the current node is a mount point in * which case walk up the mount hierarchy making sure not to * bump into the root of the mount tree (ie. dvp != udvp). * * We use dvp as a temporary variable here, it is no longer related * to the dvp above. However, we have to ensure that both *pdvp and * tdvp are locked on return. */ dvp = tdvp; while ( dvp != udvp && (dvp->v_type == VDIR) && (mp = dvp->v_mountedhere) ) { int relock_pdvp = 0; if (vfs_busy(mp, 0, 0, p)) continue; if (dvp == *pdvp) relock_pdvp = 1; vput(dvp); dvp = NULL; error = VFS_ROOT(mp, &dvp); vfs_unbusy(mp, p); if (relock_pdvp) vn_lock(*pdvp, LK_EXCLUSIVE | LK_RETRY, p); if (error) { *vpp = NULL; return (error); } } *vpp = dvp; return (0); } static int union_lookup(ap) struct vop_lookup_args /* { struct vnodeop_desc *a_desc; struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; } */ *ap; { int error; int uerror, lerror; struct vnode *uppervp, *lowervp; struct vnode *upperdvp, *lowerdvp; struct vnode *dvp = ap->a_dvp; /* starting dir */ struct union_node *dun = VTOUNION(dvp); /* associated union node */ struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; int lockparent = cnp->cn_flags & LOCKPARENT; struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); struct ucred *saved_cred = NULL; int iswhiteout; struct vattr va; *ap->a_vpp = NULLVP; /* * Disallow write attemps to the filesystem mounted read-only. */ if ((cnp->cn_flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { return (EROFS); } /* * For any lookup's we do, always return with the parent locked */ cnp->cn_flags |= LOCKPARENT; lowerdvp = dun->un_lowervp; uppervp = NULLVP; lowervp = NULLVP; iswhiteout = 0; uerror = ENOENT; lerror = ENOENT; /* * Get a private lock on uppervp and a reference, effectively * taking it out of the union_node's control. * * We must lock upperdvp while holding our lock on dvp * to avoid a deadlock. */ upperdvp = union_lock_upper(dun, p); /* * do the lookup in the upper level. * if that level comsumes additional pathnames, * then assume that something special is going * on and just return that vnode. */ if (upperdvp != NULLVP) { /* * We do not have to worry about the DOTDOT case, we've * already unlocked dvp. */ UDEBUG(("A %p\n", upperdvp)); /* * Do the lookup. We must supply a locked and referenced * upperdvp to the function and will get a new locked and * referenced upperdvp back with the old having been * dereferenced. * * If an error is returned, uppervp will be NULLVP. If no * error occurs, uppervp will be the locked and referenced * return vnode or possibly NULL, depending on what is being * requested. It is possible that the returned uppervp * will be the same as upperdvp. */ uerror = union_lookup1(um->um_uppervp, &upperdvp, &uppervp, cnp); UDEBUG(( "uerror %d upperdvp %p %d/%d, uppervp %p ref=%d/lck=%d\n", uerror, upperdvp, upperdvp->v_usecount, VOP_ISLOCKED(upperdvp), uppervp, (uppervp ? uppervp->v_usecount : -99), (uppervp ? VOP_ISLOCKED(uppervp) : -99) )); /* * Disallow write attemps to the filesystem mounted read-only. */ if (uerror == EJUSTRETURN && (cnp->cn_flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) { error = EROFS; goto out; } /* * Special case. If cn_consume != 0 skip out. The result * of the lookup is transfered to our return variable. If * an error occured we have to throw away the results. */ if (cnp->cn_consume != 0) { if ((error = uerror) == 0) { *ap->a_vpp = uppervp; uppervp = NULL; } goto out; } /* * Calculate whiteout, fall through */ if (uerror == ENOENT || uerror == EJUSTRETURN) { if (cnp->cn_flags & ISWHITEOUT) { iswhiteout = 1; } else if (lowerdvp != NULLVP) { int terror; terror = VOP_GETATTR(upperdvp, &va, cnp->cn_cred, cnp->cn_proc); if (terror == 0 && (va.va_flags & OPAQUE)) iswhiteout = 1; } } } /* * in a similar way to the upper layer, do the lookup * in the lower layer. this time, if there is some * component magic going on, then vput whatever we got * back from the upper layer and return the lower vnode * instead. */ if (lowerdvp != NULLVP && !iswhiteout) { int nameiop; UDEBUG(("B %p\n", lowerdvp)); /* * Force only LOOKUPs on the lower node, since * we won't be making changes to it anyway. */ nameiop = cnp->cn_nameiop; cnp->cn_nameiop = LOOKUP; if (um->um_op == UNMNT_BELOW) { saved_cred = cnp->cn_cred; cnp->cn_cred = um->um_cred; } /* * We shouldn't have to worry about locking interactions * between the lower layer and our union layer (w.r.t. * `..' processing) because we don't futz with lowervp * locks in the union-node instantiation code path. * * union_lookup1() requires lowervp to be locked on entry, * and it will be unlocked on return. The ref count will * not change. On return lowervp doesn't represent anything * to us so we NULL it out. */ VREF(lowerdvp); vn_lock(lowerdvp, LK_EXCLUSIVE | LK_RETRY, p); lerror = union_lookup1(um->um_lowervp, &lowerdvp, &lowervp, cnp); if (lowerdvp == lowervp) vrele(lowerdvp); else vput(lowerdvp); lowerdvp = NULL; /* lowerdvp invalid after vput */ if (um->um_op == UNMNT_BELOW) cnp->cn_cred = saved_cred; cnp->cn_nameiop = nameiop; if (cnp->cn_consume != 0 || lerror == EACCES) { if ((error = lerror) == 0) { *ap->a_vpp = lowervp; lowervp = NULL; } goto out; } } else { UDEBUG(("C %p\n", lowerdvp)); if ((cnp->cn_flags & ISDOTDOT) && dun->un_pvp != NULLVP) { if ((lowervp = LOWERVP(dun->un_pvp)) != NULL) { VREF(lowervp); vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY, p); lerror = 0; } } } /* * Ok. Now we have uerror, uppervp, upperdvp, lerror, and lowervp. * * 1. If both layers returned an error, select the upper layer. * * 2. If the upper layer faile and the bottom layer succeeded, * two subcases occur: * * a. The bottom vnode is not a directory, in which case * just return a new union vnode referencing an * empty top layer and the existing bottom layer. * * b. The button vnode is a directory, in which case * create a new directory in the top layer and * and fall through to case 3. * * 3. If the top layer succeeded then return a new union * vnode referencing whatever the new top layer and * whatever the bottom layer returned. */ /* case 1. */ if ((uerror != 0) && (lerror != 0)) { error = uerror; goto out; } /* case 2. */ if (uerror != 0 /* && (lerror == 0) */ ) { if (lowervp->v_type == VDIR) { /* case 2b. */ KASSERT(uppervp == NULL, ("uppervp unexpectedly non-NULL")); /* * oops, uppervp has a problem, we may have to shadow. */ uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); if (uerror) { error = uerror; goto out; } } } /* * Must call union_allocvp with both the upper and lower vnodes * referenced and the upper vnode locked. ap->a_vpp is returned * referenced and locked. lowervp, uppervp, and upperdvp are * absorbed by union_allocvp() whether it succeeds or fails. * * upperdvp is the parent directory of uppervp which may be * different, depending on the path, from dvp->un_uppervp. That's * why it is a separate argument. Note that it must be unlocked. * * dvp must be locked on entry to the call and will be locked on * return. */ if (uppervp && uppervp != upperdvp) VOP_UNLOCK(uppervp, 0, p); if (lowervp) VOP_UNLOCK(lowervp, 0, p); if (upperdvp) VOP_UNLOCK(upperdvp, 0, p); error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, uppervp, lowervp, 1); UDEBUG(("Create %p = %p %p refs=%d\n", *ap->a_vpp, uppervp, lowervp, (*ap->a_vpp) ? ((*ap->a_vpp)->v_usecount) : -99)); uppervp = NULL; upperdvp = NULL; lowervp = NULL; /* * Termination Code * * - put away any extra junk laying around. Note that lowervp * (if not NULL) will never be the same as *ap->a_vp and * neither will uppervp, because when we set that state we * NULL-out lowervp or uppervp. On the otherhand, upperdvp * may match uppervp or *ap->a_vpp. * * - relock/unlock dvp if appropriate. */ out: if (upperdvp) { if (upperdvp == uppervp || upperdvp == *ap->a_vpp) vrele(upperdvp); else vput(upperdvp); } if (uppervp) vput(uppervp); if (lowervp) vput(lowervp); /* * Restore LOCKPARENT state */ if (!lockparent) cnp->cn_flags &= ~LOCKPARENT; UDEBUG(("Out %d vpp %p/%d lower %p upper %p\n", error, *ap->a_vpp, ((*ap->a_vpp) ? (*ap->a_vpp)->v_usecount : -99), lowervp, uppervp)); /* * dvp lock state, determine whether to relock dvp. dvp is expected * to be locked on return if: * * - there was an error (except not EJUSTRETURN), or * - we hit the last component and lockparent is true * * dvp_is_locked is the current state of the dvp lock, not counting * the possibility that *ap->a_vpp == dvp (in which case it is locked * anyway). Note that *ap->a_vpp == dvp only if no error occured. */ if (*ap->a_vpp != dvp) { if ((error == 0 || error == EJUSTRETURN) && (!lockparent || (cnp->cn_flags & ISLASTCN) == 0)) { VOP_UNLOCK(dvp, 0, p); } } /* * Diagnostics */ #ifdef DIAGNOSTIC if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.' && *ap->a_vpp != dvp) { panic("union_lookup returning . (%p) not same as startdir (%p)", ap->a_vpp, dvp); } #endif return (error); } /* * union_create: * * a_dvp is locked on entry and remains locked on return. a_vpp is returned * locked if no error occurs, otherwise it is garbage. */ static int union_create(ap) struct vop_create_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap; { struct union_node *dun = VTOUNION(ap->a_dvp); struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct vnode *dvp; int error = EROFS; if ((dvp = union_lock_upper(dun, p)) != NULL) { struct vnode *vp; struct mount *mp; error = VOP_CREATE(dvp, &vp, cnp, ap->a_vap); if (error == 0) { mp = ap->a_dvp->v_mount; VOP_UNLOCK(vp, 0, p); UDEBUG(("ALLOCVP-1 FROM %p REFS %d\n", vp, vp->v_usecount)); error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp, NULLVP, 1); UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount)); } union_unlock_upper(dvp, p); } return (error); } static int union_whiteout(ap) struct vop_whiteout_args /* { struct vnode *a_dvp; struct componentname *a_cnp; int a_flags; } */ *ap; { struct union_node *un = VTOUNION(ap->a_dvp); struct componentname *cnp = ap->a_cnp; struct vnode *uppervp; int error = EOPNOTSUPP; if ((uppervp = union_lock_upper(un, cnp->cn_proc)) != NULLVP) { error = VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags); union_unlock_upper(uppervp, cnp->cn_proc); } return(error); } /* * union_mknod: * * a_dvp is locked on entry and should remain locked on return. * a_vpp is garbagre whether an error occurs or not. */ static int union_mknod(ap) struct vop_mknod_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap; { struct union_node *dun = VTOUNION(ap->a_dvp); struct componentname *cnp = ap->a_cnp; struct vnode *dvp; int error = EROFS; if ((dvp = union_lock_upper(dun, cnp->cn_proc)) != NULL) { error = VOP_MKNOD(dvp, ap->a_vpp, cnp, ap->a_vap); union_unlock_upper(dvp, cnp->cn_proc); } return (error); } /* * union_open: * * run open VOP. When opening the underlying vnode we have to mimic * vn_open. What we *really* need to do to avoid screwups if the * open semantics change is to call vn_open(). For example, ufs blows * up if you open a file but do not vmio it prior to writing. */ static int union_open(ap) struct vop_open_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; int a_mode; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct vnode *tvp; int mode = ap->a_mode; struct ucred *cred = ap->a_cred; struct proc *p = ap->a_p; int error = 0; int tvpisupper = 1; /* * If there is an existing upper vp then simply open that. * The upper vp takes precedence over the lower vp. When opening * a lower vp for writing copy it to the uppervp and then open the * uppervp. * * At the end of this section tvp will be left locked. */ if ((tvp = union_lock_upper(un, p)) == NULLVP) { /* * If the lower vnode is being opened for writing, then * copy the file contents to the upper vnode and open that, * otherwise can simply open the lower vnode. */ tvp = un->un_lowervp; if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { int docopy = !(mode & O_TRUNC); error = union_copyup(un, docopy, cred, p); tvp = union_lock_upper(un, p); } else { un->un_openl++; VREF(tvp); vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, p); tvpisupper = 0; } } /* * We are holding the correct vnode, open it */ if (error == 0) error = VOP_OPEN(tvp, mode, cred, p); /* * Absolutely necessary or UFS will blowup */ if (error == 0 && vn_canvmio(tvp) == TRUE) { error = vfs_object_create(tvp, p, cred); } /* * Release any locks held */ if (tvpisupper) { if (tvp) union_unlock_upper(tvp, p); } else { vput(tvp); } return (error); } /* * union_close: * * It is unclear whether a_vp is passed locked or unlocked. Whatever * the case we do not change it. */ static int union_close(ap) struct vop_close_args /* { struct vnode *a_vp; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; if ((vp = un->un_uppervp) == NULLVP) { #ifdef UNION_DIAGNOSTIC if (un->un_openl <= 0) panic("union: un_openl cnt"); #endif --un->un_openl; vp = un->un_lowervp; } ap->a_vp = vp; return (VCALL(vp, VOFFSET(vop_close), ap)); } /* * Check access permission on the union vnode. * The access check being enforced is to check * against both the underlying vnode, and any * copied vnode. This ensures that no additional * file permissions are given away simply because * the user caused an implicit file copy. */ static int union_access(ap) struct vop_access_args /* { struct vnodeop_desc *a_desc; struct vnode *a_vp; int a_mode; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_p; int error = EACCES; struct vnode *vp; /* * Disallow write attempts on filesystems mounted read-only. */ if ((ap->a_mode & VWRITE) && (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) { switch (ap->a_vp->v_type) { case VREG: case VDIR: case VLNK: return (EROFS); default: break; } } if ((vp = union_lock_upper(un, p)) != NULLVP) { ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_access), ap); union_unlock_upper(vp, p); return(error); } if ((vp = un->un_lowervp) != NULLVP) { vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); ap->a_vp = vp; /* * Remove VWRITE from a_mode if our mount point is RW, because * we want to allow writes and lowervp may be read-only. */ if ((un->un_vnode->v_mount->mnt_flag & MNT_RDONLY) == 0) ap->a_mode &= ~VWRITE; error = VCALL(vp, VOFFSET(vop_access), ap); if (error == 0) { struct union_mount *um; um = MOUNTTOUNIONMOUNT(un->un_vnode->v_mount); if (um->um_op == UNMNT_BELOW) { ap->a_cred = um->um_cred; error = VCALL(vp, VOFFSET(vop_access), ap); } } VOP_UNLOCK(vp, 0, p); } return(error); } /* * We handle getattr only to change the fsid and * track object sizes * * It's not clear whether VOP_GETATTR is to be * called with the vnode locked or not. stat() calls * it with (vp) locked, and fstat calls it with * (vp) unlocked. * * Because of this we cannot use our normal locking functions * if we do not intend to lock the main a_vp node. At the moment * we are running without any specific locking at all, but beware * to any programmer that care must be taken if locking is added * to this function. */ static int union_getattr(ap) struct vop_getattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap; { int error; struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; struct vattr *vap; struct vattr va; /* * Some programs walk the filesystem hierarchy by counting * links to directories to avoid stat'ing all the time. * This means the link count on directories needs to be "correct". * The only way to do that is to call getattr on both layers * and fix up the link count. The link count will not necessarily * be accurate but will be large enough to defeat the tree walkers. */ vap = ap->a_vap; if ((vp = un->un_uppervp) != NULLVP) { error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); if (error) return (error); /* XXX isn't this dangerouso without a lock? */ union_newsize(ap->a_vp, vap->va_size, VNOVAL); } if (vp == NULLVP) { vp = un->un_lowervp; } else if (vp->v_type == VDIR && un->un_lowervp != NULLVP) { vp = un->un_lowervp; vap = &va; } else { vp = NULLVP; } if (vp != NULLVP) { error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); if (error) return (error); /* XXX isn't this dangerous without a lock? */ union_newsize(ap->a_vp, VNOVAL, vap->va_size); } if ((vap != ap->a_vap) && (vap->va_type == VDIR)) ap->a_vap->va_nlink += vap->va_nlink; return (0); } static int union_setattr(ap) struct vop_setattr_args /* { struct vnode *a_vp; struct vattr *a_vap; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_p; struct vattr *vap = ap->a_vap; struct vnode *uppervp; int error; /* * Disallow write attempts on filesystems mounted read-only. */ if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) && (vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL)) { return (EROFS); } /* * Handle case of truncating lower object to zero size, * by creating a zero length upper object. This is to * handle the case of open with O_TRUNC and O_CREAT. */ if (un->un_uppervp == NULLVP && (un->un_lowervp->v_type == VREG)) { error = union_copyup(un, (ap->a_vap->va_size != 0), ap->a_cred, ap->a_p); if (error) return (error); } /* * Try to set attributes in upper layer, * otherwise return read-only filesystem error. */ error = EROFS; if ((uppervp = union_lock_upper(un, p)) != NULLVP) { error = VOP_SETATTR(un->un_uppervp, ap->a_vap, ap->a_cred, ap->a_p); if ((error == 0) && (ap->a_vap->va_size != VNOVAL)) union_newsize(ap->a_vp, ap->a_vap->va_size, VNOVAL); union_unlock_upper(uppervp, p); } return (error); } /* * union_getpages: */ static int union_getpages(struct vop_getpages_args *ap) { int r; r = vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, ap->a_reqpage); return(r); } /* * union_putpages: */ static int union_putpages(struct vop_putpages_args *ap) { int r; r = vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count, ap->a_sync, ap->a_rtvals); return(r); } static int union_read(ap) struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_uio->uio_procp; struct vnode *uvp; int error; uvp = union_lock_other(un, p); KASSERT(uvp != NULL, ("union_read: backing vnode missing!")); if (ap->a_vp->v_flag & VOBJBUF) union_vm_coherency(ap->a_vp, ap->a_uio, 0); error = VOP_READ(uvp, ap->a_uio, ap->a_ioflag, ap->a_cred); union_unlock_other(uvp, p); /* * XXX * perhaps the size of the underlying object has changed under * our feet. take advantage of the offset information present * in the uio structure. */ if (error == 0) { struct union_node *un = VTOUNION(ap->a_vp); off_t cur = ap->a_uio->uio_offset; if (uvp == un->un_uppervp) { if (cur > un->un_uppersz) union_newsize(ap->a_vp, cur, VNOVAL); } else { if (cur > un->un_lowersz) union_newsize(ap->a_vp, VNOVAL, cur); } } return (error); } static int union_write(ap) struct vop_read_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_uio->uio_procp; struct vnode *uppervp; int error; if ((uppervp = union_lock_upper(un, p)) == NULLVP) panic("union: missing upper layer in write"); /* * Since our VM pages are associated with our vnode rather then * the real vnode, and since we do not run our reads and writes * through our own VM cache, we have a VM/VFS coherency problem. * We solve them by invalidating or flushing the associated VM * pages prior to allowing a normal read or write to occur. * * VM-backed writes (UIO_NOCOPY) have to be converted to normal * writes because we are not cache-coherent. Normal writes need * to be made coherent with our VM-backing store, which we do by * first flushing any dirty VM pages associated with the write * range, and then destroying any clean VM pages associated with * the write range. */ if (ap->a_uio->uio_segflg == UIO_NOCOPY) { ap->a_uio->uio_segflg = UIO_SYSSPACE; } else if (ap->a_vp->v_flag & VOBJBUF) { union_vm_coherency(ap->a_vp, ap->a_uio, 1); } error = VOP_WRITE(uppervp, ap->a_uio, ap->a_ioflag, ap->a_cred); /* * the size of the underlying object may be changed by the * write. */ if (error == 0) { off_t cur = ap->a_uio->uio_offset; if (cur > un->un_uppersz) union_newsize(ap->a_vp, cur, VNOVAL); } union_unlock_upper(uppervp, p); return (error); } static int union_lease(ap) struct vop_lease_args /* { struct vnode *a_vp; struct proc *a_p; struct ucred *a_cred; int a_flag; } */ *ap; { struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_lease), ap)); } static int union_ioctl(ap) struct vop_ioctl_args /* { struct vnode *a_vp; int a_command; caddr_t a_data; int a_fflag; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_ioctl), ap)); } static int union_poll(ap) struct vop_poll_args /* { struct vnode *a_vp; int a_events; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_poll), ap)); } static int union_revoke(ap) struct vop_revoke_args /* { struct vnode *a_vp; int a_flags; struct proc *a_p; } */ *ap; { struct vnode *vp = ap->a_vp; if (UPPERVP(vp)) VOP_REVOKE(UPPERVP(vp), ap->a_flags); if (LOWERVP(vp)) VOP_REVOKE(LOWERVP(vp), ap->a_flags); vgone(vp); return (0); } static int union_mmap(ap) struct vop_mmap_args /* { struct vnode *a_vp; int a_fflags; struct ucred *a_cred; struct proc *a_p; } */ *ap; { struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_mmap), ap)); } static int union_fsync(ap) struct vop_fsync_args /* { struct vnode *a_vp; struct ucred *a_cred; int a_waitfor; struct proc *a_p; } */ *ap; { int error = 0; struct proc *p = ap->a_p; struct vnode *targetvp; struct union_node *un = VTOUNION(ap->a_vp); if ((targetvp = union_lock_other(un, p)) != NULLVP) { error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, p); union_unlock_other(targetvp, p); } return (error); } /* * union_remove: * * Remove the specified cnp. The dvp and vp are passed to us locked * and must remain locked on return. */ static int union_remove(ap) struct vop_remove_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap; { struct union_node *dun = VTOUNION(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_vp); struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct vnode *uppervp; struct vnode *upperdvp; int error; if ((upperdvp = union_lock_upper(dun, p)) == NULLVP) panic("union remove: null upper vnode"); if ((uppervp = union_lock_upper(un, p)) != NULLVP) { if (union_dowhiteout(un, cnp->cn_cred, p)) cnp->cn_flags |= DOWHITEOUT; error = VOP_REMOVE(upperdvp, uppervp, cnp); #if 0 /* XXX */ if (!error) union_removed_upper(un); #endif union_unlock_upper(uppervp, p); } else { error = union_mkwhiteout( MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount), upperdvp, ap->a_cnp, un->un_path); } union_unlock_upper(upperdvp, p); return (error); } /* * union_link: * * tdvp will be locked on entry, vp will not be locked on entry. * tdvp should remain locked on return and vp should remain unlocked * on return. */ static int union_link(ap) struct vop_link_args /* { struct vnode *a_tdvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap; { struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct union_node *dun = VTOUNION(ap->a_tdvp); struct vnode *vp; struct vnode *tdvp; int error = 0; if (ap->a_tdvp->v_op != ap->a_vp->v_op) { vp = ap->a_vp; } else { struct union_node *tun = VTOUNION(ap->a_vp); if (tun->un_uppervp == NULLVP) { vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p); #if 0 if (dun->un_uppervp == tun->un_dirvp) { if (dun->un_flags & UN_ULOCK) { dun->un_flags &= ~UN_ULOCK; VOP_UNLOCK(dun->un_uppervp, 0, p); } } #endif error = union_copyup(tun, 1, cnp->cn_cred, p); #if 0 if (dun->un_uppervp == tun->un_dirvp) { vn_lock(dun->un_uppervp, LK_EXCLUSIVE | LK_RETRY, p); dun->un_flags |= UN_ULOCK; } #endif VOP_UNLOCK(ap->a_vp, 0, p); } vp = tun->un_uppervp; } if (error) return (error); /* * Make sure upper is locked, then unlock the union directory we were * called with to avoid a deadlock while we are calling VOP_LINK on * the upper (with tdvp locked and vp not locked). Our ap->a_tdvp * is expected to be locked on return. */ if ((tdvp = union_lock_upper(dun, p)) == NULLVP) return (EROFS); VOP_UNLOCK(ap->a_tdvp, 0, p); /* unlock calling node */ error = VOP_LINK(tdvp, vp, cnp); /* call link on upper */ /* * We have to unlock tdvp prior to relocking our calling node in * order to avoid a deadlock. */ union_unlock_upper(tdvp, p); vn_lock(ap->a_tdvp, LK_EXCLUSIVE | LK_RETRY, p); return (error); } static int union_rename(ap) struct vop_rename_args /* { struct vnode *a_fdvp; struct vnode *a_fvp; struct componentname *a_fcnp; struct vnode *a_tdvp; struct vnode *a_tvp; struct componentname *a_tcnp; } */ *ap; { int error; struct vnode *fdvp = ap->a_fdvp; struct vnode *fvp = ap->a_fvp; struct vnode *tdvp = ap->a_tdvp; struct vnode *tvp = ap->a_tvp; /* * Figure out what fdvp to pass to our upper or lower vnode. If we * replace the fdvp, release the original one and ref the new one. */ if (fdvp->v_op == union_vnodeop_p) { /* always true */ struct union_node *un = VTOUNION(fdvp); if (un->un_uppervp == NULLVP) { /* * this should never happen in normal * operation but might if there was * a problem creating the top-level shadow * directory. */ error = EXDEV; goto bad; } fdvp = un->un_uppervp; VREF(fdvp); vrele(ap->a_fdvp); } /* * Figure out what fvp to pass to our upper or lower vnode. If we * replace the fvp, release the original one and ref the new one. */ if (fvp->v_op == union_vnodeop_p) { /* always true */ struct union_node *un = VTOUNION(fvp); #if 0 struct union_mount *um = MOUNTTOUNIONMOUNT(fvp->v_mount); #endif if (un->un_uppervp == NULLVP) { switch(fvp->v_type) { case VREG: vn_lock(un->un_vnode, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_proc); error = union_copyup(un, 1, ap->a_fcnp->cn_cred, ap->a_fcnp->cn_proc); VOP_UNLOCK(un->un_vnode, 0, ap->a_fcnp->cn_proc); if (error) goto bad; break; case VDIR: /* * XXX not yet. * * There is only one way to rename a directory * based in the lowervp, and that is to copy * the entire directory hierarchy. Otherwise * it would not last across a reboot. */ #if 0 vrele(fvp); fvp = NULL; vn_lock(fdvp, LK_EXCLUSIVE | LK_RETRY, ap->a_fcnp->cn_proc); error = union_mkshadow(um, fdvp, ap->a_fcnp, &un->un_uppervp); VOP_UNLOCK(fdvp, 0, ap->a_fcnp->cn_proc); if (un->un_uppervp) VOP_UNLOCK(un->un_uppervp, 0, ap->a_fcnp->cn_proc); if (error) goto bad; break; #endif default: error = EXDEV; goto bad; } } if (un->un_lowervp != NULLVP) ap->a_fcnp->cn_flags |= DOWHITEOUT; fvp = un->un_uppervp; VREF(fvp); vrele(ap->a_fvp); } /* * Figure out what tdvp (destination directory) to pass to the * lower level. If we replace it with uppervp, we need to vput the * old one. The exclusive lock is transfered to what we will pass * down in the VOP_RENAME and we replace uppervp with a simple * reference. */ if (tdvp->v_op == union_vnodeop_p) { struct union_node *un = VTOUNION(tdvp); if (un->un_uppervp == NULLVP) { /* * this should never happen in normal * operation but might if there was * a problem creating the top-level shadow * directory. */ error = EXDEV; goto bad; } /* * new tdvp is a lock and reference on uppervp, put away * the old tdvp. */ tdvp = union_lock_upper(un, ap->a_tcnp->cn_proc); vput(ap->a_tdvp); } /* * Figure out what tvp (destination file) to pass to the * lower level. * * If the uppervp file does not exist put away the (wrong) * file and change tvp to NULL. */ if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) { struct union_node *un = VTOUNION(tvp); tvp = union_lock_upper(un, ap->a_tcnp->cn_proc); vput(ap->a_tvp); /* note: tvp may be NULL */ } /* * VOP_RENAME releases/vputs prior to returning, so we have no * cleanup to do. */ return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp)); /* * Error. We still have to release / vput the various elements. */ bad: vrele(fdvp); if (fvp) vrele(fvp); vput(tdvp); if (tvp != NULLVP) { if (tvp != tdvp) vput(tvp); else vrele(tvp); } return (error); } static int union_mkdir(ap) struct vop_mkdir_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; } */ *ap; { struct union_node *dun = VTOUNION(ap->a_dvp); struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct vnode *upperdvp; int error = EROFS; if ((upperdvp = union_lock_upper(dun, p)) != NULLVP) { struct vnode *vp; error = VOP_MKDIR(upperdvp, &vp, cnp, ap->a_vap); union_unlock_upper(upperdvp, p); if (error == 0) { VOP_UNLOCK(vp, 0, p); UDEBUG(("ALLOCVP-2 FROM %p REFS %d\n", vp, vp->v_usecount)); error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp, NULLVP, cnp, vp, NULLVP, 1); UDEBUG(("ALLOCVP-2B FROM %p REFS %d\n", *ap->a_vpp, vp->v_usecount)); } } return (error); } static int union_rmdir(ap) struct vop_rmdir_args /* { struct vnode *a_dvp; struct vnode *a_vp; struct componentname *a_cnp; } */ *ap; { struct union_node *dun = VTOUNION(ap->a_dvp); struct union_node *un = VTOUNION(ap->a_vp); struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct vnode *upperdvp; struct vnode *uppervp; int error; if ((upperdvp = union_lock_upper(dun, p)) == NULLVP) panic("union rmdir: null upper vnode"); if ((uppervp = union_lock_upper(un, p)) != NULLVP) { if (union_dowhiteout(un, cnp->cn_cred, p)) cnp->cn_flags |= DOWHITEOUT; error = VOP_RMDIR(upperdvp, uppervp, ap->a_cnp); union_unlock_upper(uppervp, p); } else { error = union_mkwhiteout( MOUNTTOUNIONMOUNT(ap->a_dvp->v_mount), dun->un_uppervp, ap->a_cnp, un->un_path); } union_unlock_upper(upperdvp, p); return (error); } /* * union_symlink: * * dvp is locked on entry and remains locked on return. a_vpp is garbage * (unused). */ static int union_symlink(ap) struct vop_symlink_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; struct vattr *a_vap; char *a_target; } */ *ap; { struct union_node *dun = VTOUNION(ap->a_dvp); struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct vnode *dvp; int error = EROFS; if ((dvp = union_lock_upper(dun, p)) != NULLVP) { error = VOP_SYMLINK(dvp, ap->a_vpp, cnp, ap->a_vap, ap->a_target); union_unlock_upper(dvp, p); } return (error); } /* * union_readdir works in concert with getdirentries and * readdir(3) to provide a list of entries in the unioned * directories. getdirentries is responsible for walking * down the union stack. readdir(3) is responsible for * eliminating duplicate names from the returned data stream. */ static int union_readdir(ap) struct vop_readdir_args /* { struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; int *a_eofflag; u_long *a_cookies; int a_ncookies; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); struct proc *p = ap->a_uio->uio_procp; struct vnode *uvp; int error = 0; if ((uvp = union_lock_upper(un, p)) != NULLVP) { ap->a_vp = uvp; error = VCALL(uvp, VOFFSET(vop_readdir), ap); union_unlock_upper(uvp, p); } return(error); } static int union_readlink(ap) struct vop_readlink_args /* { struct vnode *a_vp; struct uio *a_uio; struct ucred *a_cred; } */ *ap; { int error; struct union_node *un = VTOUNION(ap->a_vp); struct uio *uio = ap->a_uio; struct proc *p = uio->uio_procp; struct vnode *vp; vp = union_lock_other(un, p); KASSERT(vp != NULL, ("union_readlink: backing vnode missing!")); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_readlink), ap); union_unlock_other(vp, p); return (error); } /* * union_abortop: * * dvp is locked on entry and left locked on return * */ static int union_abortop(ap) struct vop_abortop_args /* { struct vnode *a_dvp; struct componentname *a_cnp; } */ *ap; { struct componentname *cnp = ap->a_cnp; struct proc *p = cnp->cn_proc; struct union_node *un = VTOUNION(ap->a_dvp); int islocked = VOP_ISLOCKED(ap->a_dvp); struct vnode *vp; int error; if (islocked) { vp = union_lock_other(un, p); } else { vp = OTHERVP(ap->a_dvp); } KASSERT(vp != NULL, ("union_abortop: backing vnode missing!")); ap->a_dvp = vp; error = VCALL(vp, VOFFSET(vop_abortop), ap); if (islocked) union_unlock_other(vp, p); return (error); } /* * union_inactive: * * Called with the vnode locked. We are expected to unlock the vnode. */ static int union_inactive(ap) struct vop_inactive_args /* { struct vnode *a_vp; struct proc *a_p; } */ *ap; { struct vnode *vp = ap->a_vp; struct proc *p = ap->a_p; struct union_node *un = VTOUNION(vp); struct vnode **vpp; /* * Do nothing (and _don't_ bypass). * Wait to vrele lowervp until reclaim, * so that until then our union_node is in the * cache and reusable. * * NEEDSWORK: Someday, consider inactive'ing * the lowervp and then trying to reactivate it * with capabilities (v_id) * like they do in the name lookup cache code. * That's too much work for now. */ if (un->un_dircache != 0) { for (vpp = un->un_dircache; *vpp != NULLVP; vpp++) vrele(*vpp); free (un->un_dircache, M_TEMP); un->un_dircache = 0; } #if 0 if ((un->un_flags & UN_ULOCK) && un->un_uppervp) { un->un_flags &= ~UN_ULOCK; VOP_UNLOCK(un->un_uppervp, 0, p); } #endif VOP_UNLOCK(vp, 0, p); if ((un->un_flags & UN_CACHED) == 0) vgone(vp); return (0); } static int union_reclaim(ap) struct vop_reclaim_args /* { struct vnode *a_vp; } */ *ap; { union_freevp(ap->a_vp); return (0); } static int union_lock(ap) struct vop_lock_args *ap; { #if 0 struct vnode *vp = ap->a_vp; struct proc *p = ap->a_p; int flags = ap->a_flags; struct union_node *un; #endif int error; error = vop_stdlock(ap); #if 0 un = VTOUNION(vp); if (error == 0) { /* * Lock the upper if it exists and this is an exclusive lock * request. */ if (un->un_uppervp != NULLVP && (flags & LK_TYPE_MASK) == LK_EXCLUSIVE) { if ((un->un_flags & UN_ULOCK) == 0 && vp->v_usecount) { error = vn_lock(un->un_uppervp, flags, p); if (error) { struct vop_unlock_args uap = { 0 }; uap.a_vp = ap->a_vp; uap.a_flags = ap->a_flags; uap.a_p = ap->a_p; vop_stdunlock(&uap); return (error); } un->un_flags |= UN_ULOCK; } } } #endif return (error); } /* * union_unlock: * * Unlock our union node. This also unlocks uppervp. */ static int union_unlock(ap) struct vop_unlock_args /* { struct vnode *a_vp; int a_flags; struct proc *a_p; } */ *ap; { struct union_node *un = VTOUNION(ap->a_vp); int error; KASSERT((un->un_uppervp == NULL || un->un_uppervp->v_usecount > 0), ("uppervp usecount is 0")); error = vop_stdunlock(ap); #if 0 /* * If no exclusive locks remain and we are holding an uppervp lock, * remove the uppervp lock. */ if ((un->un_flags & UN_ULOCK) && lockstatus(&un->un_lock) != LK_EXCLUSIVE) { un->un_flags &= ~UN_ULOCK; VOP_UNLOCK(un->un_uppervp, LK_EXCLUSIVE, p); } #endif return(error); } /* * union_bmap: * * There isn't much we can do. We cannot push through to the real vnode * to get to the underlying device because this will bypass data * cached by the real vnode. * * For some reason we cannot return the 'real' vnode either, it seems * to blow up memory maps. */ static int union_bmap(ap) struct vop_bmap_args /* { struct vnode *a_vp; daddr_t a_bn; struct vnode **a_vpp; daddr_t *a_bnp; int *a_runp; int *a_runb; } */ *ap; { return(EOPNOTSUPP); } static int union_print(ap) struct vop_print_args /* { struct vnode *a_vp; } */ *ap; { struct vnode *vp = ap->a_vp; printf("\ttag VT_UNION, vp=%p, uppervp=%p, lowervp=%p\n", vp, UPPERVP(vp), LOWERVP(vp)); if (UPPERVP(vp) != NULLVP) vprint("union: upper", UPPERVP(vp)); if (LOWERVP(vp) != NULLVP) vprint("union: lower", LOWERVP(vp)); return (0); } static int union_pathconf(ap) struct vop_pathconf_args /* { struct vnode *a_vp; int a_name; int *a_retval; } */ *ap; { int error; struct proc *p = curproc; /* XXX */ struct union_node *un = VTOUNION(ap->a_vp); struct vnode *vp; vp = union_lock_other(un, p); KASSERT(vp != NULL, ("union_pathconf: backing vnode missing!")); ap->a_vp = vp; error = VCALL(vp, VOFFSET(vop_pathconf), ap); union_unlock_other(vp, p); return (error); } static int union_advlock(ap) struct vop_advlock_args /* { struct vnode *a_vp; caddr_t a_id; int a_op; struct flock *a_fl; int a_flags; } */ *ap; { register struct vnode *ovp = OTHERVP(ap->a_vp); ap->a_vp = ovp; return (VCALL(ovp, VOFFSET(vop_advlock), ap)); } /* * XXX - vop_strategy must be hand coded because it has no * YYY - and it is not coherent with anything * * vnode in its arguments. * This goes away with a merged VM/buffer cache. */ static int union_strategy(ap) struct vop_strategy_args /* { struct vnode *a_vp; struct buf *a_bp; } */ *ap; { struct buf *bp = ap->a_bp; struct vnode *othervp = OTHERVP(bp->b_vp); #ifdef DIAGNOSTIC if (othervp == NULLVP) panic("union_strategy: nil vp"); if (((bp->b_flags & B_READ) == 0) && (othervp == LOWERVP(bp->b_vp))) panic("union_strategy: writing to lowervp"); #endif return (VOP_STRATEGY(othervp, bp)); } /* * Global vfs data structures */ vop_t **union_vnodeop_p; static struct vnodeopv_entry_desc union_vnodeop_entries[] = { { &vop_default_desc, (vop_t *) vop_defaultop }, { &vop_abortop_desc, (vop_t *) union_abortop }, { &vop_access_desc, (vop_t *) union_access }, { &vop_advlock_desc, (vop_t *) union_advlock }, { &vop_bmap_desc, (vop_t *) union_bmap }, { &vop_close_desc, (vop_t *) union_close }, { &vop_create_desc, (vop_t *) union_create }, { &vop_fsync_desc, (vop_t *) union_fsync }, { &vop_getpages_desc, (vop_t *) union_getpages }, { &vop_putpages_desc, (vop_t *) union_putpages }, { &vop_getattr_desc, (vop_t *) union_getattr }, { &vop_inactive_desc, (vop_t *) union_inactive }, { &vop_ioctl_desc, (vop_t *) union_ioctl }, { &vop_islocked_desc, (vop_t *) vop_stdislocked }, { &vop_lease_desc, (vop_t *) union_lease }, { &vop_link_desc, (vop_t *) union_link }, { &vop_lock_desc, (vop_t *) union_lock }, { &vop_lookup_desc, (vop_t *) union_lookup }, { &vop_mkdir_desc, (vop_t *) union_mkdir }, { &vop_mknod_desc, (vop_t *) union_mknod }, { &vop_mmap_desc, (vop_t *) union_mmap }, { &vop_open_desc, (vop_t *) union_open }, { &vop_pathconf_desc, (vop_t *) union_pathconf }, { &vop_poll_desc, (vop_t *) union_poll }, { &vop_print_desc, (vop_t *) union_print }, { &vop_read_desc, (vop_t *) union_read }, { &vop_readdir_desc, (vop_t *) union_readdir }, { &vop_readlink_desc, (vop_t *) union_readlink }, { &vop_reclaim_desc, (vop_t *) union_reclaim }, { &vop_remove_desc, (vop_t *) union_remove }, { &vop_rename_desc, (vop_t *) union_rename }, { &vop_revoke_desc, (vop_t *) union_revoke }, { &vop_rmdir_desc, (vop_t *) union_rmdir }, { &vop_setattr_desc, (vop_t *) union_setattr }, { &vop_strategy_desc, (vop_t *) union_strategy }, { &vop_symlink_desc, (vop_t *) union_symlink }, { &vop_unlock_desc, (vop_t *) union_unlock }, { &vop_whiteout_desc, (vop_t *) union_whiteout }, { &vop_write_desc, (vop_t *) union_write }, { NULL, NULL } }; static struct vnodeopv_desc union_vnodeop_opv_desc = { &union_vnodeop_p, union_vnodeop_entries }; VNODEOP_SET(union_vnodeop_opv_desc);