protect vgoneall from other vgone's

SCCS-vsn: sys/kern/vfs_subr.c 7.36

diff --git a/usr/src/sys/kern/vfs_subr.c b/usr/src/sys/kern/vfs_subr.c
index ee6b9ee..bf22dce 100644 (file)
--- a/usr/src/sys/kern/vfs_subr.c
+++ b/usr/src/sys/kern/vfs_subr.c
@@ -14,7 +14,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *

- *     @(#)vfs_subr.c  7.35 (Berkeley) %G%
+ *     @(#)vfs_subr.c  7.36 (Berkeley) %G%

  */
 
 /*
  */
 
 /*


@@ -618,14 +618,36 @@ void vgoneall(vp)
 {
        register struct vnode *vq;
 
 {
        register struct vnode *vq;
 

-       while (vp->v_flag & VALIASED) {
-               for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
-                       if (vq->v_rdev != vp->v_rdev ||
-                           vq->v_type != vp->v_type || vp == vq)
-                               continue;
-                       vgone(vq);
-                       break;
+       if (vp->v_flag & VALIASED) {
+               /*
+                * If a vgone (or vclean) is already in progress,
+                * wait until it is done and return.
+                */
+               if (vp->v_flag & VXLOCK) {
+                       vp->v_flag |= VXWANT;
+                       sleep((caddr_t)vp, PINOD);
+                       return;

                }
                }

+               /*
+                * Ensure that vp will not be vgone'd while we
+                * are eliminating its aliases.
+                */
+               vp->v_flag |= VXLOCK;
+               while (vp->v_flag & VALIASED) {
+                       for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
+                               if (vq->v_rdev != vp->v_rdev ||
+                                   vq->v_type != vp->v_type || vp == vq)
+                                       continue;
+                               vgone(vq);
+                               break;
+                       }
+               }
+               /*
+                * Remove the lock so that vgone below will
+                * really eliminate the vnode after which time
+                * vgone will awaken any sleepers.
+                */
+               vp->v_flag &= ~VXLOCK;

        }
        vgone(vp);
 }
        }
        vgone(vp);
 }