fixup fsid correctly in union_getattr

[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 63eda50..14d124b 100644 (file)
--- a/usr/src/sys/miscfs/union/union_vnops.c
+++ b/usr/src/sys/miscfs/union/union_vnops.c
@@ -8,7 +8,7 @@
  *
  * %sccs.include.redist.c%
  *
  *
  * %sccs.include.redist.c%
  *

- *     @(#)union_vnops.c       8.2 (Berkeley) %G%
+ *     @(#)union_vnops.c       8.16 (Berkeley) %G%

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


@@ -25,17 +25,35 @@
 #include <sys/queue.h>
 #include <miscfs/union/union.h>
 
 #include <sys/queue.h>
 #include <miscfs/union/union.h>
 

+#define FIXUP(un) { \
+       if (((un)->un_flags & UN_ULOCK) == 0) { \
+               union_fixup(un); \
+       } \
+}
+
+static void
+union_fixup(un)
+       struct union_node *un;
+{
+
+       VOP_LOCK(un->un_uppervp);
+       un->un_flags |= UN_ULOCK;
+}
+

 static int
 static int

-union_lookup1(udvp, dvp, vpp, cnp)
+union_lookup1(udvp, dvpp, vpp, cnp)

        struct vnode *udvp;
        struct vnode *udvp;

-       struct vnode *dvp;
+       struct vnode **dvpp;

        struct vnode **vpp;
        struct componentname *cnp;
 {
        int error;
        struct vnode *tdvp;
        struct vnode **vpp;
        struct componentname *cnp;
 {
        int error;
        struct vnode *tdvp;

+       struct vnode *dvp;

        struct mount *mp;
 
        struct mount *mp;
 

+       dvp = *dvpp;
+

        /*
         * If stepping up the directory tree, check for going
         * back across the mount point, in which case do what
        /*
         * If stepping up the directory tree, check for going
         * back across the mount point, in which case do what


@@ -43,18 +61,15 @@ union_lookup1(udvp, dvp, vpp, cnp)
         * hierarchy.
         */
        if (cnp->cn_flags & ISDOTDOT) {
         * hierarchy.
         */
        if (cnp->cn_flags & ISDOTDOT) {

-               for (;;) {
+               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.
                         */
                        /*
                         * Don't do the NOCROSSMOUNT check
                         * at this level.  By definition,
                         * union fs deals with namespaces, not
                         * filesystems.
                         */

-                       if ((dvp->v_flag & VROOT) == 0)
-                               break;
-

                        tdvp = dvp;
                        tdvp = dvp;

-                       dvp = dvp->v_mount->mnt_vnodecovered;
+                       *dvpp = dvp = dvp->v_mount->mnt_vnodecovered;

                        vput(tdvp);
                        VREF(dvp);
                        VOP_LOCK(dvp);
                        vput(tdvp);
                        VREF(dvp);
                        VOP_LOCK(dvp);


@@ -121,6 +136,7 @@ union_lookup(ap)
        int lockparent = cnp->cn_flags & LOCKPARENT;
        int rdonly = cnp->cn_flags & RDONLY;
        struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);
        int lockparent = cnp->cn_flags & LOCKPARENT;
        int rdonly = cnp->cn_flags & RDONLY;
        struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount);

+       struct ucred *saved_cred;

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


@@ -135,8 +151,9 @@ union_lookup(ap)
         * then assume that something special is going
         * on and just return that vnode.
         */
         * then assume that something special is going
         * on and just return that vnode.
         */

-       if (upperdvp) {
-               uerror = union_lookup1(um->um_uppervp, upperdvp,
+       if (upperdvp != NULLVP) {
+               FIXUP(dun);
+               uerror = union_lookup1(um->um_uppervp, &upperdvp,

                                        &uppervp, cnp);
                /*if (uppervp == upperdvp)
                        dun->un_flags |= UN_KLOCK;*/
                                        &uppervp, cnp);
                /*if (uppervp == upperdvp)
                        dun->un_flags |= UN_KLOCK;*/


@@ -158,7 +175,7 @@ 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) {
+       if (lowerdvp != NULLVP) {

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


@@ -169,15 +186,21 @@ union_lookup(ap)
                 */
                nameiop = cnp->cn_nameiop;
                cnp->cn_nameiop = LOOKUP;
                 */
                nameiop = cnp->cn_nameiop;
                cnp->cn_nameiop = LOOKUP;

-               lerror = union_lookup1(um->um_lowervp, lowerdvp,
+               if (um->um_op == UNMNT_BELOW) {
+                       saved_cred = cnp->cn_cred;
+                       cnp->cn_cred = um->um_cred;
+               }
+               lerror = union_lookup1(um->um_lowervp, &lowerdvp,

                                &lowervp, cnp);
                                &lowervp, cnp);

+               if (um->um_op == UNMNT_BELOW)
+                       cnp->cn_cred = saved_cred;

                cnp->cn_nameiop = nameiop;
 
                if (lowervp != lowerdvp)
                        VOP_UNLOCK(lowerdvp);
 
                if (cnp->cn_consume != 0) {
                cnp->cn_nameiop = nameiop;
 
                if (lowervp != lowerdvp)
                        VOP_UNLOCK(lowerdvp);
 
                if (cnp->cn_consume != 0) {

-                       if (uppervp) {
+                       if (uppervp != NULLVP) {

                                if (uppervp == upperdvp)
                                        vrele(uppervp);
                                else
                                if (uppervp == upperdvp)
                                        vrele(uppervp);
                                else


@@ -237,7 +260,7 @@ union_lookup(ap)
                        dun->un_flags |= UN_ULOCK;
 
                        if (uerror) {
                        dun->un_flags |= UN_ULOCK;
 
                        if (uerror) {

-                               if (lowervp) {
+                               if (lowervp != NULLVP) {

                                        vput(lowervp);
                                        lowervp = NULLVP;
                                }
                                        vput(lowervp);
                                        lowervp = NULLVP;
                                }


@@ -246,16 +269,16 @@ union_lookup(ap)
                }
        }
 
                }
        }
 

-       if (lowervp)
+       if (lowervp != NULLVP)

                VOP_UNLOCK(lowervp);
 
        error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
                              uppervp, lowervp);
 
        if (error) {
                VOP_UNLOCK(lowervp);
 
        error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp,
                              uppervp, lowervp);
 
        if (error) {

-               if (uppervp)
+               if (uppervp != NULLVP)

                        vput(uppervp);
                        vput(uppervp);

-               if (lowervp)
+               if (lowervp != NULLVP)

                        vrele(lowervp);
        } else {
                if (*ap->a_vpp != dvp)
                        vrele(lowervp);
        } else {
                if (*ap->a_vpp != dvp)


@@ -278,10 +301,12 @@ union_create(ap)
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 

-       if (dvp) {
+       if (dvp != NULLVP) {

                int error;
                struct vnode *vp;
 
                int error;
                struct vnode *vp;
 

+               FIXUP(un);
+

                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);


@@ -318,10 +343,12 @@ union_mknod(ap)
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 

-       if (dvp) {
+       if (dvp != NULLVP) {

                int error;
                struct vnode *vp;
 
                int error;
                struct vnode *vp;
 

+               FIXUP(un);
+

                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);


@@ -329,7 +356,7 @@ union_mknod(ap)
                if (error)
                        return (error);
 
                if (error)
                        return (error);
 

-               if (vp) {
+               if (vp != NULLVP) {

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


@@ -377,75 +404,7 @@ union_open(ap)
                 */
                tvp = un->un_lowervp;
                if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) {
                 */
                tvp = un->un_lowervp;
                if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) {

-                       struct vnode *vp;
-                       int i;
-
-                       /*
-                        * Open the named file in the upper layer.  Note that
-                        * the file may have come into existence *since* the
-                        * lookup was done, since the upper layer may really
-                        * be a loopback mount of some other filesystem...
-                        * so open the file with exclusive create and barf if
-                        * it already exists.
-                        * XXX - perhaps should re-lookup the node (once more
-                        * with feeling) and simply open that.  Who knows.
-                        */
-                       error = union_vn_create(&vp, un, p);
-                       if (error)
-                               return (error);
-
-                       /* at this point, uppervp is locked */
-                       union_newupper(un, vp);
-                       un->un_flags |= UN_ULOCK;
-
-                       /*
-                        * Now, if the file is being opened with truncation,
-                        * then the (new) upper vnode is ready to fly,
-                        * otherwise the data from the lower vnode must be
-                        * copied to the upper layer first.  This only works
-                        * for regular files (check is made above).
-                        */
-                       if ((mode & O_TRUNC) == 0) {
-                               /*
-                                * XXX - should not ignore errors
-                                * from VOP_CLOSE
-                                */
-                               VOP_LOCK(tvp);
-                               error = VOP_OPEN(tvp, FREAD, cred, p);
-                               if (error == 0) {
-                                       error = union_copyfile(p, cred,
-                                                      tvp, un->un_uppervp);
-                                       VOP_UNLOCK(tvp);
-                                       (void) VOP_CLOSE(tvp, FREAD);
-                               } else {
-                                       VOP_UNLOCK(tvp);
-                               }
-
-                               un->un_flags &= ~UN_ULOCK;
-                               VOP_UNLOCK(un->un_uppervp);
-                               union_vn_close(un->un_uppervp, FWRITE, cred, p);
-                               VOP_LOCK(un->un_uppervp);
-                               un->un_flags |= UN_ULOCK;
-
-                               if (!error)
-                                       uprintf("union: copied up %s\n",
-                                                               un->un_path);
-                       }
-
-                       /*
-                        * Subsequent IOs will go to the top layer, so
-                        * call close on the lower vnode and open on the
-                        * upper vnode to ensure that the filesystem keeps
-                        * its references counts right.  This doesn't do
-                        * the right thing with (cred) and (FREAD) though.
-                        * Ignoring error returns is not righ, either.
-                        */
-                       for (i = 0; i < un->un_openl; i++) {
-                               (void) VOP_CLOSE(tvp, FREAD);
-                               (void) VOP_OPEN(un->un_uppervp, FREAD, cred, p);
-                       }
-                       un->un_openl = 0;
-
+                       error = union_copyup(un, (mode&O_TRUNC) == 0, cred, p);

                        if (error == 0)
                                error = VOP_OPEN(un->un_uppervp, mode, cred, p);
                        return (error);
                        if (error == 0)
                                error = VOP_OPEN(un->un_uppervp, mode, cred, p);
                        return (error);


@@ -462,6 +421,8 @@ union_open(ap)
                return (error);
        }
 
                return (error);
        }
 

+       FIXUP(un);
+

        error = VOP_OPEN(tvp, mode, cred, p);
 
        return (error);
        error = VOP_OPEN(tvp, mode, cred, p);
 
        return (error);


@@ -479,7 +440,7 @@ union_close(ap)
        struct union_node *un = VTOUNION(ap->a_vp);
        struct vnode *vp;
 
        struct union_node *un = VTOUNION(ap->a_vp);
        struct vnode *vp;
 

-       if (un->un_uppervp) {
+       if (un->un_uppervp != NULLVP) {

                vp = un->un_uppervp;
        } else {
 #ifdef UNION_DIAGNOSTIC
                vp = un->un_uppervp;
        } else {
 #ifdef UNION_DIAGNOSTIC


@@ -512,25 +473,35 @@ union_access(ap)
        } */ *ap;
 {
        struct union_node *un = VTOUNION(ap->a_vp);
        } */ *ap;
 {
        struct union_node *un = VTOUNION(ap->a_vp);

-       int error = 0;
+       int error = EACCES;

        struct vnode *vp;
 
        struct vnode *vp;
 

-       if (vp = un->un_lowervp) {
+       if ((vp = un->un_uppervp) != NULLVP) {
+               FIXUP(un);
+               return (VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p));
+       }
+
+       if ((vp = un->un_lowervp) != NULLVP) {

                VOP_LOCK(vp);
                error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p);
                VOP_LOCK(vp);
                error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p);

+               if (error == 0) {
+                       struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount);
+
+                       if (um->um_op == UNMNT_BELOW)
+                               error = VOP_ACCESS(vp, ap->a_mode,
+                                               um->um_cred, ap->a_p);
+               }

                VOP_UNLOCK(vp);
                if (error)
                        return (error);
        }
 
                VOP_UNLOCK(vp);
                if (error)
                        return (error);
        }
 

-       if (vp = un->un_uppervp)
-               error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p);
-

        return (error);
 }
 
 /*
        return (error);
 }
 
 /*

- *  We handle getattr only to change the fsid.
+ * We handle getattr only to change the fsid and
+ * track object sizes

  */
 int
 union_getattr(ap)
  */
 int
 union_getattr(ap)


@@ -542,16 +513,63 @@ union_getattr(ap)
        } */ *ap;
 {
        int error;
        } */ *ap;
 {
        int error;

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

 
 

-       if (dolock)
+
+       /*
+        * 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;
+
+       vp = un->un_uppervp;
+       if (vp != NULLVP) {
+               /*
+                * 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.
+                * In the mean time, compensate here by checking
+                * the union_node's lock flag.
+                */
+               if (un->un_flags & UN_LOCKED)
+                       FIXUP(un);
+
+               error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);
+               if (error)
+                       return (error);
+               union_newsize(ap->a_vp, vap->va_size, VNOVAL);
+       }
+
+       if (vp == NULLVP) {
+               vp = un->un_lowervp;
+       } else if (vp->v_type == VDIR) {
+               vp = un->un_lowervp;
+               vap = &va;
+       } else {
+               vp = NULLVP;
+       }
+
+       if (vp != NULLVP) {

                VOP_LOCK(vp);
                VOP_LOCK(vp);

-       error = VOP_GETATTR(vp, ap->a_vap, ap->a_cred, ap->a_p);
-       if (dolock)
+               error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p);

                VOP_UNLOCK(vp);
                VOP_UNLOCK(vp);

+               if (error)
+                       return (error);
+               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;

 
 

-       /* Requires that arguments be restored. */

        ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
        return (0);
 }
        ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
        return (0);
 }


@@ -568,15 +586,41 @@ union_setattr(ap)
        struct union_node *un = VTOUNION(ap->a_vp);
        int error;
 
        struct union_node *un = VTOUNION(ap->a_vp);
        int error;
 

-       if (un->un_uppervp) {
+       /*
+        * 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) &&
+           /* 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);
+               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;
+       }
+
+       /*
+        * Try to set attributes in upper layer,
+        * otherwise return read-only filesystem error.
+        */
+       if (un->un_uppervp != NULLVP) {
+               FIXUP(un);

                error = VOP_SETATTR(un->un_uppervp, ap->a_vap,
                                        ap->a_cred, ap->a_p);
                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);

        } else {
        } else {

-               /*
-                * XXX should do a copyfile (perhaps only if
-                * the file permission change, which would not
-                * track va_ctime correctly).
-                */

                error = EROFS;
        }
 
                error = EROFS;
        }
 


@@ -598,10 +642,31 @@ union_read(ap)
 
        if (dolock)
                VOP_LOCK(vp);
 
        if (dolock)
                VOP_LOCK(vp);

+       else
+               FIXUP(VTOUNION(ap->a_vp));

        error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
        if (dolock)
                VOP_UNLOCK(vp);
 
        error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
        if (dolock)
                VOP_UNLOCK(vp);
 

+       /*
+        * 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 (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);
+               }
+       }
+

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


@@ -620,10 +685,29 @@ union_write(ap)
 
        if (dolock)
                VOP_LOCK(vp);
 
        if (dolock)
                VOP_LOCK(vp);

+       else
+               FIXUP(VTOUNION(ap->a_vp));

        error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
        if (dolock)
                VOP_UNLOCK(vp);
 
        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) {
+               struct union_node *un = VTOUNION(ap->a_vp);
+               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);
+               }
+       }
+

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


@@ -684,11 +768,13 @@ union_fsync(ap)
        int error = 0;
        struct vnode *targetvp = OTHERVP(ap->a_vp);
 
        int error = 0;
        struct vnode *targetvp = OTHERVP(ap->a_vp);
 

-       if (targetvp) {
+       if (targetvp != NULLVP) {

                int dolock = (targetvp == LOWERVP(ap->a_vp));
 
                if (dolock)
                        VOP_LOCK(targetvp);
                int dolock = (targetvp == LOWERVP(ap->a_vp));
 
                if (dolock)
                        VOP_LOCK(targetvp);

+               else
+                       FIXUP(VTOUNION(ap->a_vp));

                error = VOP_FSYNC(targetvp, ap->a_cred,
                                        ap->a_waitfor, ap->a_p);
                if (dolock)
                error = VOP_FSYNC(targetvp, ap->a_cred,
                                        ap->a_waitfor, ap->a_p);
                if (dolock)


@@ -723,13 +809,15 @@ 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 && un->un_uppervp) {
+       if (dun->un_uppervp != NULLVP && 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;
 

+               FIXUP(dun);

                VREF(dvp);
                dun->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);
                VREF(dvp);
                dun->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);

+               FIXUP(un);

                VREF(vp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);
                VREF(vp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);


@@ -761,32 +849,49 @@ union_link(ap)
                struct componentname *a_cnp;
        } */ *ap;
 {
                struct componentname *a_cnp;
        } */ *ap;
 {

-       int error;
-       struct union_node *dun = VTOUNION(ap->a_vp);
-       struct union_node *un = VTOUNION(ap->a_tdvp);
-
-       if (dun->un_uppervp && un->un_uppervp) {
-               struct vnode *dvp = dun->un_uppervp;
-               struct vnode *vp = un->un_uppervp;
+       int error = 0;
+       struct union_node *un;
+       struct vnode *vp;
+       struct vnode *tdvp;

 
 

-               VREF(dvp);
-               dun->un_flags |= UN_KLOCK;
-               vput(ap->a_vp);
-               VREF(vp);
-               vrele(ap->a_tdvp);
+       un = VTOUNION(ap->a_vp);

 
 

-               error = VOP_LINK(dvp, vp, ap->a_cnp);
+       if (ap->a_vp->v_op != ap->a_tdvp->v_op) {
+               tdvp = ap->a_tdvp;

        } else {
        } else {

-               /*
-                * XXX: need to copy to upper layer
-                * and do the link there.
-                */
-               vput(ap->a_vp);
-               vrele(ap->a_tdvp);
+               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) {
+                               un->un_flags &= ~UN_ULOCK;
+                               VOP_UNLOCK(un->un_uppervp);
+                       }
+                       error = union_copyup(tdun, 1, ap->a_cnp->cn_cred,
+                                               ap->a_cnp->cn_proc);
+                       if (un->un_uppervp == tdun->un_dirvp) {
+                               VOP_LOCK(un->un_uppervp);
+                               un->un_flags |= UN_ULOCK;
+                       }
+                       VOP_UNLOCK(ap->a_tdvp);
+               }
+               tdvp = tdun->un_uppervp;
+       }
+
+       vp = un->un_uppervp;
+       if (vp == NULLVP)

                error = EROFS;
                error = EROFS;

+
+       if (error) {
+               vput(ap->a_vp);
+               return (error);

        }
 
        }
 

-       return (error);
+       FIXUP(un);
+       VREF(vp);
+       un->un_flags |= UN_KLOCK;
+       vput(ap->a_vp);
+
+       return (VOP_LINK(vp, tdvp, ap->a_cnp));

 }
 
 int
 }
 
 int


@@ -834,6 +939,12 @@ union_rename(ap)
        if (tdvp->v_op == union_vnodeop_p) {
                struct union_node *un = VTOUNION(tdvp);
                if (un->un_uppervp == NULLVP) {
        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 = EROFS;
                        goto bad;
                }
                        error = EROFS;
                        goto bad;
                }


@@ -844,16 +955,14 @@ union_rename(ap)
                vput(ap->a_tdvp);
        }
 
                vput(ap->a_tdvp);
        }
 

-       if (tvp && tvp->v_op == union_vnodeop_p) {
+       if (tvp != NULLVP && tvp->v_op == union_vnodeop_p) {

                struct union_node *un = VTOUNION(tvp);
                struct union_node *un = VTOUNION(tvp);

-               if (un->un_uppervp == NULLVP) {
-                       error = EROFS;
-                       goto bad;
-               }

 
                tvp = un->un_uppervp;
 
                tvp = un->un_uppervp;

-               VREF(tvp);
-               un->un_flags |= UN_KLOCK;
+               if (tvp != NULLVP) {
+                       VREF(tvp);
+                       un->un_flags |= UN_KLOCK;
+               }

                vput(ap->a_tvp);
        }
 
                vput(ap->a_tvp);
        }
 


@@ -863,7 +972,7 @@ bad:
        vrele(fdvp);
        vrele(fvp);
        vput(tdvp);
        vrele(fdvp);
        vrele(fvp);
        vput(tdvp);

-       if (tvp)
+       if (tvp != NULLVP)

                vput(tvp);
 
        return (error);
                vput(tvp);
 
        return (error);


@@ -881,10 +990,11 @@ union_mkdir(ap)
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 

-       if (dvp) {
+       if (dvp != NULLVP) {

                int error;
                struct vnode *vp;
 
                int error;
                struct vnode *vp;
 

+               FIXUP(un);

                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);


@@ -921,13 +1031,15 @@ 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 && un->un_uppervp) {
+       if (dun->un_uppervp != NULLVP && 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;
 

+               FIXUP(dun);

                VREF(dvp);
                dun->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);
                VREF(dvp);
                dun->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);

+               FIXUP(un);

                VREF(vp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);
                VREF(vp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_vp);


@@ -964,11 +1076,12 @@ union_symlink(ap)
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 
        struct union_node *un = VTOUNION(ap->a_dvp);
        struct vnode *dvp = un->un_uppervp;
 

-       if (dvp) {
+       if (dvp != NULLVP) {

                int error;
                struct vnode *vp;
                struct mount *mp = ap->a_dvp->v_mount;
 
                int error;
                struct vnode *vp;
                struct mount *mp = ap->a_dvp->v_mount;
 

+               FIXUP(un);

                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);
                VREF(dvp);
                un->un_flags |= UN_KLOCK;
                vput(ap->a_dvp);


@@ -996,15 +1109,20 @@ union_readdir(ap)
                struct vnode *a_vp;
                struct uio *a_uio;
                struct ucred *a_cred;
                struct vnode *a_vp;
                struct uio *a_uio;
                struct ucred *a_cred;

+               int *a_eofflag;
+               u_long *a_cookies;
+               int a_ncookies;

        } */ *ap;
 {
        } */ *ap;
 {

-       int error = 0;
-       struct union_node *un = VTOUNION(ap->a_vp);
+       register struct union_node *un = VTOUNION(ap->a_vp);
+       register struct vnode *uvp = un->un_uppervp;

 
 

-       if (un->un_uppervp)
-               error = VOP_READDIR(un->un_uppervp, ap->a_uio, ap->a_cred);
+       if (uvp == NULLVP)
+               return (0);

 
 

-       return (error);
+       FIXUP(un);
+       ap->a_vp = uvp;
+       return (VOCALL(uvp->v_op, VOFFSET(vop_readdir), ap));

 }
 
 int
 }
 
 int


@@ -1021,6 +1139,8 @@ union_readlink(ap)
 
        if (dolock)
                VOP_LOCK(vp);
 
        if (dolock)
                VOP_LOCK(vp);

+       else
+               FIXUP(VTOUNION(ap->a_vp));

        error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
        if (dolock)
                VOP_UNLOCK(vp);
        error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
        if (dolock)
                VOP_UNLOCK(vp);


@@ -1041,8 +1161,12 @@ union_abortop(ap)
        int islocked = un->un_flags & UN_LOCKED;
        int dolock = (vp == LOWERVP(ap->a_dvp));
 
        int islocked = un->un_flags & UN_LOCKED;
        int dolock = (vp == LOWERVP(ap->a_dvp));
 

-       if (islocked && dolock)
-               VOP_LOCK(vp);
+       if (islocked) {
+               if (dolock)
+                       VOP_LOCK(vp);
+               else
+                       FIXUP(VTOUNION(ap->a_dvp));
+       }

        error = VOP_ABORTOP(vp, ap->a_cnp);
        if (islocked && dolock)
                VOP_UNLOCK(vp);
        error = VOP_ABORTOP(vp, ap->a_cnp);
        if (islocked && dolock)
                VOP_UNLOCK(vp);


@@ -1056,6 +1180,7 @@ union_inactive(ap)
                struct vnode *a_vp;
        } */ *ap;
 {
                struct vnode *a_vp;
        } */ *ap;
 {

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

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


@@ -1071,12 +1196,15 @@ union_inactive(ap)
         */
 
 #ifdef UNION_DIAGNOSTIC
         */
 
 #ifdef UNION_DIAGNOSTIC

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

        if (un->un_flags & UN_LOCKED)
                panic("union: inactivating locked node");
        if (un->un_flags & UN_LOCKED)
                panic("union: inactivating locked node");

+       if (un->un_flags & UN_ULOCK)
+               panic("union: inactivating w/locked upper node");

 #endif
 
 #endif
 

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

        return (0);
 }
 
        return (0);
 }
 


@@ -1096,12 +1224,22 @@ int
 union_lock(ap)
        struct vop_lock_args *ap;
 {
 union_lock(ap)
        struct vop_lock_args *ap;
 {

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

 
 

-       if (un->un_uppervp) {
-               if ((un->un_flags & UN_ULOCK) == 0) {
-                       VOP_LOCK(un->un_uppervp);
+start:
+       while (vp->v_flag & VXLOCK) {
+               vp->v_flag |= VXWANT;
+               sleep((caddr_t)vp, PINOD);
+       }
+
+       un = VTOUNION(vp);
+
+       if (un->un_uppervp != NULLVP) {
+               if (((un->un_flags & UN_ULOCK) == 0) &&
+                   (vp->v_usecount != 0)) {

                        un->un_flags |= UN_ULOCK;
                        un->un_flags |= UN_ULOCK;

+                       VOP_LOCK(un->un_uppervp);

                }
 #ifdef DIAGNOSTIC
                if (un->un_flags & UN_KLOCK)
                }
 #ifdef DIAGNOSTIC
                if (un->un_flags & UN_KLOCK)


@@ -1109,7 +1247,7 @@ union_lock(ap)
 #endif
        }
 
 #endif
        }
 

-       while (un->un_flags & UN_LOCKED) {
+       if (un->un_flags & UN_LOCKED) {

 #ifdef DIAGNOSTIC
                if (curproc && un->un_pid == curproc->p_pid &&
                            un->un_pid > -1 && curproc->p_pid > -1)
 #ifdef DIAGNOSTIC
                if (curproc && un->un_pid == curproc->p_pid &&
                            un->un_pid > -1 && curproc->p_pid > -1)


@@ -1117,8 +1255,8 @@ union_lock(ap)
 #endif
                un->un_flags |= UN_WANT;
                sleep((caddr_t) &un->un_flags, PINOD);
 #endif
                un->un_flags |= UN_WANT;
                sleep((caddr_t) &un->un_flags, PINOD);

+               goto start;

        }
        }

-       un->un_flags |= UN_LOCKED;

 
 #ifdef DIAGNOSTIC
        if (curproc)
 
 #ifdef DIAGNOSTIC
        if (curproc)


@@ -1127,6 +1265,7 @@ union_lock(ap)
                un->un_pid = -1;
 #endif
 
                un->un_pid = -1;
 #endif
 

+       un->un_flags |= UN_LOCKED;

        return (0);
 }
 
        return (0);
 }
 


@@ -1179,6 +1318,8 @@ union_bmap(ap)
 
        if (dolock)
                VOP_LOCK(vp);
 
        if (dolock)
                VOP_LOCK(vp);

+       else
+               FIXUP(VTOUNION(ap->a_vp));

        error = VOP_BMAP(vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp);
        if (dolock)
                VOP_UNLOCK(vp);
        error = VOP_BMAP(vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp);
        if (dolock)
                VOP_UNLOCK(vp);


@@ -1223,6 +1364,8 @@ union_pathconf(ap)
 
        if (dolock)
                VOP_LOCK(vp);
 
        if (dolock)
                VOP_LOCK(vp);

+       else
+               FIXUP(VTOUNION(ap->a_vp));

        error = VOP_PATHCONF(vp, ap->a_name, ap->a_retval);
        if (dolock)
                VOP_UNLOCK(vp);
        error = VOP_PATHCONF(vp, ap->a_name, ap->a_retval);
        if (dolock)
                VOP_UNLOCK(vp);