add union_revoke operator

[unix-history] / usr / src / sys / miscfs / union / union_vnops.c

diff --git a/usr/src/sys/miscfs/union/union_vnops.c b/usr/src/sys/miscfs/union/union_vnops.c
index 6c257f9..2de83d4 100644 (file)
--- a/usr/src/sys/miscfs/union/union_vnops.c
+++ b/usr/src/sys/miscfs/union/union_vnops.c
@@ -1,14 +1,14 @@
 /*
 /*

- * Copyright (c) 1992, 1993, 1994 The Regents of the University of California.
- * Copyright (c) 1992, 1993, 1994 Jan-Simon Pendry.
- * All rights reserved.
+ * 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.
  *
  * %sccs.include.redist.c%
  *
  *
  * This code is derived from software contributed to Berkeley by
  * Jan-Simon Pendry.
  *
  * %sccs.include.redist.c%
  *

- *     @(#)union_vnops.c       8.17 (Berkeley) %G%
+ *     @(#)union_vnops.c       8.26 (Berkeley) %G%

  */
 
 #include <sys/param.h>
  */
 
 #include <sys/param.h>


@@ -16,6 +16,7 @@
 #include <sys/proc.h>
 #include <sys/file.h>
 #include <sys/time.h>
 #include <sys/proc.h>
 #include <sys/file.h>
 #include <sys/time.h>

+#include <sys/stat.h>

 #include <sys/types.h>
 #include <sys/vnode.h>
 #include <sys/mount.h>
 #include <sys/types.h>
 #include <sys/vnode.h>
 #include <sys/mount.h>


@@ -137,6 +138,24 @@ union_lookup(ap)
        int rdonly = cnp->cn_flags & RDONLY;
        struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
        struct ucred *saved_cred;
        int rdonly = cnp->cn_flags & RDONLY;
        struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
        struct ucred *saved_cred;

+       int iswhiteout;
+       struct vattr va;
+
+#ifdef notyet
+       if (cnp->cn_namelen == 3 &&
+                       cnp->cn_nameptr[2] == '.' &&
+                       cnp->cn_nameptr[1] == '.' &&
+                       cnp->cn_nameptr[0] == '.') {
+               dvp = *ap->a_vpp = LOWERVP(ap->a_dvp);
+               if (dvp == NULLVP)
+                       return (ENOENT);
+               VREF(dvp);
+               VOP_LOCK(dvp);
+               if (!lockparent || !(cnp->cn_flags & ISLASTCN))
+                       VOP_UNLOCK(ap->a_dvp);
+               return (0);
+       }
+#endif

 
        cnp->cn_flags |= LOCKPARENT;
 
 
        cnp->cn_flags |= LOCKPARENT;
 


@@ -144,6 +163,7 @@ union_lookup(ap)
        lowerdvp = dun->un_lowervp;
        uppervp = NULLVP;
        lowervp = NULLVP;
        lowerdvp = dun->un_lowervp;
        uppervp = NULLVP;
        lowervp = NULLVP;

+       iswhiteout = 0;

 
        /*
         * do the lookup in the upper level.
 
        /*
         * do the lookup in the upper level.


@@ -164,6 +184,16 @@ union_lookup(ap)
                                cnp->cn_flags &= ~LOCKPARENT;
                        return (uerror);
                }
                                cnp->cn_flags &= ~LOCKPARENT;
                        return (uerror);
                }

+               if (uerror == ENOENT || uerror == EJUSTRETURN) {
+                       if (cnp->cn_flags & ISWHITEOUT) {
+                               iswhiteout = 1;
+                       } else if (lowerdvp != NULLVP) {
+                               lerror = VOP_GETATTR(upperdvp, &va,
+                                       cnp->cn_cred, cnp->cn_proc);
+                               if (lerror == 0 && (va.va_flags & OPAQUE))
+                                       iswhiteout = 1;
+                       }
+               }

        } else {
                uerror = ENOENT;
        }
        } else {
                uerror = ENOENT;
        }


@@ -175,7 +205,7 @@ union_lookup(ap)
         * back from the upper layer and return the lower vnode
         * instead.
         */
         * back from the upper layer and return the lower vnode
         * instead.
         */

-       if (lowerdvp != NULLVP) {
+       if (lowerdvp != NULLVP && !iswhiteout) {

                int nameiop;
 
                VOP_LOCK(lowerdvp);
                int nameiop;
 
                VOP_LOCK(lowerdvp);


@@ -281,7 +311,7 @@ union_lookup(ap)
                VOP_UNLOCK(lowervp);
 
        error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
                VOP_UNLOCK(lowervp);
 
        error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,

-                             uppervp, lowervp);
+                             uppervp, lowervp, 1);

 
        if (error) {
                if (uppervp != NULLVP)
 
        if (error) {
                if (uppervp != NULLVP)


@@ -312,11 +342,13 @@ union_create(ap)
        if (dvp != NULLVP) {
                int error;
                struct vnode *vp;
        if (dvp != NULLVP) {
                int error;
                struct vnode *vp;

+               struct mount *mp;

 
                FIXUP(un);
 
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
 
                FIXUP(un);
 
                VREF(dvp);
                un->un_flags |= UN_KLOCK;

+               mp = ap->a_dvp->v_mount;

                vput(ap->a_dvp);
                error = VOP_CREATE(dvp, &vp, ap->a_cnp, ap->a_vap);
                if (error)
                vput(ap->a_dvp);
                error = VOP_CREATE(dvp, &vp, ap->a_cnp, ap->a_vap);
                if (error)


@@ -324,12 +356,13 @@ union_create(ap)
 
                error = union_allocvp(
                                ap->a_vpp,
 
                error = union_allocvp(
                                ap->a_vpp,

-                               ap->a_dvp->v_mount,
-                               ap->a_dvp,
+                               mp,
+                               NULLVP,

                                NULLVP,
                                ap->a_cnp,
                                vp,
                                NULLVP,
                                ap->a_cnp,
                                vp,

-                               NULLVP);
+                               NULLVP,
+                               1);

                if (error)
                        vput(vp);
                return (error);
                if (error)
                        vput(vp);
                return (error);


@@ -339,6 +372,23 @@ union_create(ap)
        return (EROFS);
 }
 
        return (EROFS);
 }
 

+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);
+
+       if (un->un_uppervp == NULLVP)
+               return (EOPNOTSUPP);
+
+       FIXUP(un);
+       return (VOP_WHITEOUT(un->un_uppervp, ap->a_cnp, ap->a_flags));
+}
+

 int
 union_mknod(ap)
        struct vop_mknod_args /* {
 int
 union_mknod(ap)
        struct vop_mknod_args /* {


@@ -354,11 +404,13 @@ union_mknod(ap)
        if (dvp != NULLVP) {
                int error;
                struct vnode *vp;
        if (dvp != NULLVP) {
                int error;
                struct vnode *vp;

+               struct mount *mp;

 
                FIXUP(un);
 
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
 
                FIXUP(un);
 
                VREF(dvp);
                un->un_flags |= UN_KLOCK;

+               mp = ap->a_dvp->v_mount;

                vput(ap->a_dvp);
                error = VOP_MKNOD(dvp, &vp, ap->a_cnp, ap->a_vap);
                if (error)
                vput(ap->a_dvp);
                error = VOP_MKNOD(dvp, &vp, ap->a_cnp, ap->a_vap);
                if (error)


@@ -367,12 +419,13 @@ union_mknod(ap)
                if (vp != NULLVP) {
                        error = union_allocvp(
                                        ap->a_vpp,
                if (vp != NULLVP) {
                        error = union_allocvp(
                                        ap->a_vpp,

-                                       ap->a_dvp->v_mount,
-                                       ap->a_dvp,
+                                       mp,
+                                       NULLVP,

                                        NULLVP,
                                        ap->a_cnp,
                                        vp,
                                        NULLVP,
                                        ap->a_cnp,
                                        vp,

-                                       NULLVP);
+                                       NULLVP,
+                                       1);

                        if (error)
                                vput(vp);
                }
                        if (error)
                                vput(vp);
                }


@@ -567,9 +620,7 @@ union_getattr(ap)
        }
 
        if (vp != NULLVP) {
        }
 
        if (vp != NULLVP) {

-               VOP_LOCK(vp);

                error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
                error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);

-               VOP_UNLOCK(vp);

                if (error)
                        return (error);
                union_newsize(ap->a_vp, VNOVAL, vap->va_size);
                if (error)
                        return (error);
                union_newsize(ap->a_vp, VNOVAL, vap->va_size);


@@ -601,21 +652,11 @@ union_setattr(ap)
         */
        if ((un->un_uppervp == NULLVP) &&
            /* assert(un->un_lowervp != NULLVP) */
         */
        if ((un->un_uppervp == NULLVP) &&
            /* assert(un->un_lowervp != NULLVP) */

-           (un->un_lowervp->v_type == VREG) &&
-           (ap->a_vap->va_size == 0)) {
-               struct vnode *vp;
-
-               error = union_vn_create(&vp, un, ap->a_p);
+           (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);
                if (error)
                        return (error);

-
-               /* at this point, uppervp is locked */
-               union_newupper(un, vp);
-
-               VOP_UNLOCK(vp);
-               union_vn_close(un->un_uppervp, FWRITE, ap->a_cred, ap->a_p);
-               VOP_LOCK(vp);
-               un->un_flags |= UN_ULOCK;

        }
 
        /*
        }
 
        /*


@@ -688,37 +729,42 @@ union_write(ap)
        } */ *ap;
 {
        int error;
        } */ *ap;
 {
        int error;

-       struct vnode *vp = OTHERVP(ap->a_vp);
-       int dolock = (vp == LOWERVP(ap->a_vp));
+       struct vnode *vp;
+       struct union_node *un = VTOUNION(ap->a_vp);

 
 

-       if (dolock)
-               VOP_LOCK(vp);
-       else
-               FIXUP(VTOUNION(ap->a_vp));
+       vp = UPPERVP(ap->a_vp);
+       if (vp == NULLVP)
+               panic("union: missing upper layer in write");
+
+       FIXUP(un);

        error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
        error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);

-       if (dolock)
-               VOP_UNLOCK(vp);

 
        /*
         * the size of the underlying object may be changed by the
         * write.
         */
        if (error == 0) {
 
        /*
         * the size of the underlying object may be changed by the
         * write.
         */
        if (error == 0) {

-               struct union_node *un = VTOUNION(ap->a_vp);

                off_t cur = ap->a_uio->uio_offset;
 
                off_t cur = ap->a_uio->uio_offset;
 

-               if (vp == 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);
-               }
+               if (cur > un->un_uppersz)
+                       union_newsize(ap->a_vp, cur, VNOVAL);

        }
 
        return (error);
 }
 
        }
 
        return (error);
 }
 

+union_lease(ap)
+       struct vop_lease_args /* {
+               struct vnode *a_vp;
+               struct proc *a_p;
+               struct ucred *a_cred;
+               int a_flag;
+       } */ *ap;
+{
+
+       return (VOP_LEASE(OTHERVP(ap->a_vp), ap->a_p, ap->a_cred, ap->a_flag));
+}
+

 int
 union_ioctl(ap)
        struct vop_ioctl_args /* {
 int
 union_ioctl(ap)
        struct vop_ioctl_args /* {


@@ -750,6 +796,22 @@ union_select(ap)
                                ap->a_cred, ap->a_p));
 }
 
                                ap->a_cred, ap->a_p));
 }
 

+int
+union_revoke(ap)
+       struct vop_revoke_args /* {
+               struct vnode *a_vp;
+               int a_flags;
+       } */ *ap;
+{
+       struct vnode *vp = ap->a_vp;
+
+       if (UPPERVP(vp))
+               VOP_REVOKE(UPPERVP(vp), ap->a_flags);
+       if (LOWERVP(vp))
+               VOP_REVOKE(UPPERVP(vp), ap->a_flags);
+       vgone(vp);
+}
+

 int
 union_mmap(ap)
        struct vop_mmap_args /* {
 int
 union_mmap(ap)
        struct vop_mmap_args /* {


@@ -817,9 +879,13 @@ union_remove(ap)
        struct union_node *dun = VTOUNION(ap->a_dvp);
        struct union_node *un = VTOUNION(ap->a_vp);
 
        struct union_node *dun = VTOUNION(ap->a_dvp);
        struct union_node *un = VTOUNION(ap->a_vp);
 

-       if (dun->un_uppervp != NULLVP && un->un_uppervp != NULLVP) {
+       if (dun->un_uppervp == NULLVP)
+               panic("union remove: null upper vnode");
+
+       if (un->un_uppervp != NULLVP) {

                struct vnode *dvp = dun->un_uppervp;
                struct vnode *vp = un->un_uppervp;
                struct vnode *dvp = dun->un_uppervp;
                struct vnode *vp = un->un_uppervp;

+               struct componentname *cnp = ap->a_cnp;

 
                FIXUP(dun);
                VREF(dvp);
 
                FIXUP(dun);
                VREF(dvp);


@@ -830,20 +896,18 @@ union_remove(ap)
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);
 
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);
 

-               error = VOP_REMOVE(dvp, vp, ap->a_cnp);
+               if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc))
+                       cnp->cn_flags |= DOWHITEOUT;
+               error = VOP_REMOVE(dvp, vp, cnp);

                if (!error)
                        union_removed_upper(un);
                if (!error)
                        union_removed_upper(un);

-
-               /*
-                * XXX: should create a whiteout here
-                */

        } else {
        } else {

-               /*
-                * XXX: should create a whiteout here
-                */
+               FIXUP(dun);
+               error = union_mkwhiteout(
+                       MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
+                       dun->un_uppervp, ap->a_cnp, un->un_path);

                vput(ap->a_dvp);
                vput(ap->a_vp);
                vput(ap->a_dvp);
                vput(ap->a_vp);

-               error = EROFS;

        }
 
        return (error);
        }
 
        return (error);


@@ -862,42 +926,42 @@ union_link(ap)
        struct vnode *vp;
        struct vnode *tdvp;
 
        struct vnode *vp;
        struct vnode *tdvp;
 

-       un = VTOUNION(ap->a_vp);
+       un = VTOUNION(ap->a_tdvp);

 
 

-       if (ap->a_vp->v_op != ap->a_tdvp->v_op) {
-               tdvp = ap->a_tdvp;
+       if (ap->a_tdvp->v_op != ap->a_vp->v_op) {
+               vp = ap->a_vp;

        } else {
        } else {

-               struct union_node *tdun = VTOUNION(ap->a_tdvp);
-               if (tdun->un_uppervp == NULLVP) {
-                       VOP_LOCK(ap->a_tdvp);
-                       if (un->un_uppervp == tdun->un_dirvp) {
+               struct union_node *tun = VTOUNION(ap->a_vp);
+               if (tun->un_uppervp == NULLVP) {
+                       VOP_LOCK(ap->a_vp);
+                       if (un->un_uppervp == tun->un_dirvp) {

                                un->un_flags &= ~UN_ULOCK;
                                VOP_UNLOCK(un->un_uppervp);
                        }
                                un->un_flags &= ~UN_ULOCK;
                                VOP_UNLOCK(un->un_uppervp);
                        }

-                       error = union_copyup(tdun, 1, ap->a_cnp->cn_cred,
+                       error = union_copyup(tun, 1, ap->a_cnp->cn_cred,

                                                ap->a_cnp->cn_proc);
                                                ap->a_cnp->cn_proc);

-                       if (un->un_uppervp == tdun->un_dirvp) {
+                       if (un->un_uppervp == tun->un_dirvp) {

                                VOP_LOCK(un->un_uppervp);
                                un->un_flags |= UN_ULOCK;
                        }
                                VOP_LOCK(un->un_uppervp);
                                un->un_flags |= UN_ULOCK;
                        }

-                       VOP_UNLOCK(ap->a_tdvp);
+                       VOP_UNLOCK(ap->a_vp);

                }
                }

-               tdvp = tdun->un_uppervp;
+               vp = tun->un_uppervp;

        }
 
        }
 

-       vp = un->un_uppervp;
-       if (vp == NULLVP)
+       tdvp = un->un_uppervp;
+       if (tdvp == NULLVP)

                error = EROFS;
 
        if (error) {
                error = EROFS;
 
        if (error) {

-               vput(ap->a_vp);
+               vput(ap->a_tdvp);

                return (error);
        }
 
        FIXUP(un);
                return (error);
        }
 
        FIXUP(un);

-       VREF(vp);
+       VREF(tdvp);

        un->un_flags |= UN_KLOCK;
        un->un_flags |= UN_KLOCK;

-       vput(ap->a_vp);
+       vput(ap->a_tdvp);

 
        return (VOP_LINK(vp, tdvp, ap->a_cnp));
 }
 
        return (VOP_LINK(vp, tdvp, ap->a_cnp));
 }


@@ -923,7 +987,13 @@ union_rename(ap)
        if (fdvp->v_op == union_vnodeop_p) {    /* always true */
                struct union_node *un = VTOUNION(fdvp);
                if (un->un_uppervp == NULLVP) {
        if (fdvp->v_op == union_vnodeop_p) {    /* always true */
                struct union_node *un = VTOUNION(fdvp);
                if (un->un_uppervp == NULLVP) {

-                       error = EROFS;
+                       /*
+                        * this should never happen in normal
+                        * operation but might if there was
+                        * a problem creating the top-level shadow
+                        * directory.
+                        */
+                       error = EXDEV;

                        goto bad;
                }
 
                        goto bad;
                }
 


@@ -935,10 +1005,14 @@ union_rename(ap)
        if (fvp->v_op == union_vnodeop_p) {     /* always true */
                struct union_node *un = VTOUNION(fvp);
                if (un->un_uppervp == NULLVP) {
        if (fvp->v_op == union_vnodeop_p) {     /* always true */
                struct union_node *un = VTOUNION(fvp);
                if (un->un_uppervp == NULLVP) {

-                       error = EROFS;
+                       /* XXX: should do a copyup */
+                       error = EXDEV;

                        goto bad;
                }
 
                        goto bad;
                }
 

+               if (un->un_lowervp != NULLVP)
+                       ap->a_fcnp->cn_flags |= DOWHITEOUT;
+

                fvp = un->un_uppervp;
                VREF(fvp);
                vrele(ap->a_fvp);
                fvp = un->un_uppervp;
                VREF(fvp);
                vrele(ap->a_fvp);


@@ -953,7 +1027,7 @@ union_rename(ap)
                         * a problem creating the top-level shadow
                         * directory.
                         */
                         * a problem creating the top-level shadow
                         * directory.
                         */

-                       error = EROFS;
+                       error = EXDEV;

                        goto bad;
                }
 
                        goto bad;
                }
 


@@ -1005,10 +1079,12 @@ union_mkdir(ap)
                FIXUP(un);
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                FIXUP(un);
                VREF(dvp);
                un->un_flags |= UN_KLOCK;

-               vput(ap->a_dvp);
+               VOP_UNLOCK(ap->a_dvp);

                error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap);
                error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap);

-               if (error)
+               if (error) {
+                       vrele(ap->a_dvp);

                        return (error);
                        return (error);

+               }

 
                error = union_allocvp(
                                ap->a_vpp,
 
                error = union_allocvp(
                                ap->a_vpp,


@@ -1017,7 +1093,9 @@ union_mkdir(ap)
                                NULLVP,
                                ap->a_cnp,
                                vp,
                                NULLVP,
                                ap->a_cnp,
                                vp,

-                               NULLVP);
+                               NULLVP,
+                               1);
+               vrele(ap->a_dvp);

                if (error)
                        vput(vp);
                return (error);
                if (error)
                        vput(vp);
                return (error);


@@ -1039,9 +1117,13 @@ union_rmdir(ap)
        struct union_node *dun = VTOUNION(ap->a_dvp);
        struct union_node *un = VTOUNION(ap->a_vp);
 
        struct union_node *dun = VTOUNION(ap->a_dvp);
        struct union_node *un = VTOUNION(ap->a_vp);
 

-       if (dun->un_uppervp != NULLVP && un->un_uppervp != NULLVP) {
+       if (dun->un_uppervp == NULLVP)
+               panic("union rmdir: null upper vnode");
+
+       if (un->un_uppervp != NULLVP) {

                struct vnode *dvp = dun->un_uppervp;
                struct vnode *vp = un->un_uppervp;
                struct vnode *dvp = dun->un_uppervp;
                struct vnode *vp = un->un_uppervp;

+               struct componentname *cnp = ap->a_cnp;

 
                FIXUP(dun);
                VREF(dvp);
 
                FIXUP(dun);
                VREF(dvp);


@@ -1052,20 +1134,18 @@ union_rmdir(ap)
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);
 
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);
 

+               if (union_dowhiteout(un, cnp->cn_cred, cnp->cn_proc))
+                       cnp->cn_flags |= DOWHITEOUT;

                error = VOP_RMDIR(dvp, vp, ap->a_cnp);
                if (!error)
                        union_removed_upper(un);
                error = VOP_RMDIR(dvp, vp, ap->a_cnp);
                if (!error)
                        union_removed_upper(un);

-
-               /*
-                * XXX: should create a whiteout here
-                */

        } else {
        } else {

-               /*
-                * XXX: should create a whiteout here
-                */
+               FIXUP(dun);
+               error = union_mkwhiteout(
+                       MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
+                       dun->un_uppervp, ap->a_cnp, un->un_path);

                vput(ap->a_dvp);
                vput(ap->a_vp);
                vput(ap->a_dvp);
                vput(ap->a_vp);

-               error = EROFS;

        }
 
        return (error);
        }
 
        return (error);


@@ -1189,6 +1269,7 @@ union_inactive(ap)
        } */ *ap;
 {
        struct union_node *un = VTOUNION(ap->a_vp);
        } */ *ap;
 {
        struct union_node *un = VTOUNION(ap->a_vp);

+       struct vnode **vpp;

 
        /*
         * Do nothing (and _don't_ bypass).
 
        /*
         * Do nothing (and _don't_ bypass).


@@ -1210,6 +1291,13 @@ union_inactive(ap)
                panic("union: inactivating w/locked upper node");
 #endif
 
                panic("union: inactivating w/locked upper node");
 #endif
 

+       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 ((un->un_flags & UN_CACHED) == 0)
                vgone(ap->a_vp);
 
        if ((un->un_flags & UN_CACHED) == 0)
                vgone(ap->a_vp);
 


@@ -1246,12 +1334,14 @@ start:
        if (un->un_uppervp != NULLVP) {
                if (((un->un_flags & UN_ULOCK) == 0) &&
                    (vp->v_usecount != 0)) {
        if (un->un_uppervp != NULLVP) {
                if (((un->un_flags & UN_ULOCK) == 0) &&
                    (vp->v_usecount != 0)) {

-                       un->un_flags |= UN_ULOCK;

                        VOP_LOCK(un->un_uppervp);
                        VOP_LOCK(un->un_uppervp);

+                       un->un_flags |= UN_ULOCK;

                }
 #ifdef DIAGNOSTIC
                }
 #ifdef DIAGNOSTIC

-               if (un->un_flags & UN_KLOCK)
-                       panic("union: dangling upper lock");
+               if (un->un_flags & UN_KLOCK) {
+                       vprint("union: dangling klock", vp);
+                       panic("union: dangling upper lock (%lx)", vp);
+               }

 #endif
        }
 
 #endif
        }
 


@@ -1277,6 +1367,17 @@ start:
        return (0);
 }
 
        return (0);
 }
 

+/*
+ * When operations want to vput() a union node yet retain a lock on
+ * the upper vnode (say, to do some further operations like link(),
+ * mkdir(), ...), they set UN_KLOCK on the union node, then call
+ * vput() which calls VOP_UNLOCK() and comes here.  union_unlock()
+ * unlocks the union node (leaving the upper vnode alone), clears the
+ * KLOCK flag, and then returns to vput().  The caller then does whatever
+ * is left to do with the upper vnode, and ensures that it gets unlocked.
+ *
+ * If UN_KLOCK isn't set, then the upper vnode is unlocked here.
+ */

 int
 union_unlock(ap)
        struct vop_lock_args *ap;
 int
 union_unlock(ap)
        struct vop_lock_args *ap;


@@ -1345,6 +1446,11 @@ union_print(ap)
 
        printf("\ttag VT_UNION, vp=%x, uppervp=%x, lowervp=%x\n",
                        vp, UPPERVP(vp), LOWERVP(vp));
 
        printf("\ttag VT_UNION, vp=%x, uppervp=%x, lowervp=%x\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);
 }
 
        return (0);
 }
 


@@ -1437,6 +1543,7 @@ struct vnodeopv_entry_desc union_vnodeop_entries[] = {
        { &vop_default_desc, vn_default_error },
        { &vop_lookup_desc, union_lookup },             /* lookup */
        { &vop_create_desc, union_create },             /* create */
        { &vop_default_desc, vn_default_error },
        { &vop_lookup_desc, union_lookup },             /* lookup */
        { &vop_create_desc, union_create },             /* create */

+       { &vop_whiteout_desc, union_whiteout },         /* whiteout */

        { &vop_mknod_desc, union_mknod },               /* mknod */
        { &vop_open_desc, union_open },                 /* open */
        { &vop_close_desc, union_close },               /* close */
        { &vop_mknod_desc, union_mknod },               /* mknod */
        { &vop_open_desc, union_open },                 /* open */
        { &vop_close_desc, union_close },               /* close */


@@ -1445,8 +1552,10 @@ struct vnodeopv_entry_desc union_vnodeop_entries[] = {
        { &vop_setattr_desc, union_setattr },           /* setattr */
        { &vop_read_desc, union_read },                 /* read */
        { &vop_write_desc, union_write },               /* write */
        { &vop_setattr_desc, union_setattr },           /* setattr */
        { &vop_read_desc, union_read },                 /* read */
        { &vop_write_desc, union_write },               /* write */

+       { &vop_lease_desc, union_lease },               /* lease */

        { &vop_ioctl_desc, union_ioctl },               /* ioctl */
        { &vop_select_desc, union_select },             /* select */
        { &vop_ioctl_desc, union_ioctl },               /* ioctl */
        { &vop_select_desc, union_select },             /* select */

+       { &vop_revoke_desc, union_revoke },             /* revoke */

        { &vop_mmap_desc, union_mmap },                 /* mmap */
        { &vop_fsync_desc, union_fsync },               /* fsync */
        { &vop_seek_desc, union_seek },                 /* seek */
        { &vop_mmap_desc, union_mmap },                 /* mmap */
        { &vop_fsync_desc, union_fsync },               /* fsync */
        { &vop_seek_desc, union_seek },                 /* seek */