Pseudofs was leaking VFS cache entries badly due to its cache and use of

the wrong VOP descriptor.  This misuse caused VFS-cached vnodes to be
re-cached, resulting in the leak.  This commit is an interim fix until DES
has a chance to rework the code involved.

2 files changed, 22 insertions, 4 deletions

diff --git a/sys/fs/pseudofs/pseudofs_vncache.c b/sys/fs/pseudofs/pseudofs_vncache.c
index 71f6159..333e325 100644
--- a/sys/fs/pseudofs/pseudofs_vncache.c
+++ b/sys/fs/pseudofs/pseudofs_vncache.c
@@ -105,9 +105,11 @@ pfs_vncache_alloc(struct mount *mp, struct vnode **vpp,
 {
 	struct pfs_vdata *pvd;
 	int error;
-	
-	/* see if the vnode is in the cache */
-	/* XXX linear search... not very efficient */
+
+	/*
+	 * See if the vnode is in the cache.  
+	 * XXX linear search is not very efficient.
+	 */
 	mtx_lock(&pfs_vncache_mutex);
 	for (pvd = pfs_vncache; pvd; pvd = pvd->pvd_next) {
 		if (pvd->pvd_pn == pn && pvd->pvd_pid == pid) {
@@ -115,6 +117,8 @@ pfs_vncache_alloc(struct mount *mp, struct vnode **vpp,
 				++pfs_vncache_hits;
 				*vpp = pvd->pvd_vnode;
 				mtx_unlock(&pfs_vncache_mutex);
+				/* XXX see comment at top of pfs_lookup() */
+				cache_purge(*vpp);
 				return (0);
 			}
 			/* XXX if this can happen, we're in trouble */
@@ -176,6 +180,8 @@ int
 pfs_vncache_free(struct vnode *vp)
 {
 	struct pfs_vdata *pvd;
+
+	cache_purge(vp);
 	
 	mtx_lock(&pfs_vncache_mutex);
 	pvd = (struct pfs_vdata *)vp->v_data;
diff --git a/sys/fs/pseudofs/pseudofs_vnops.c b/sys/fs/pseudofs/pseudofs_vnops.c
index e7741b8..769ff30 100644
--- a/sys/fs/pseudofs/pseudofs_vnops.c
+++ b/sys/fs/pseudofs/pseudofs_vnops.c
@@ -293,6 +293,15 @@ pfs_getextattr(struct vop_getextattr_args *va)
 
 /*
  * Look up a file or directory
+ *
+ * XXX NOTE!  pfs_lookup() has been hooked into vop_lookup_desc!  This
+ * will result in a lookup operation for a vnode which may already be
+ * cached, therefore we have to be careful to purge the VFS cache when
+ * reusing a vnode.
+ *
+ * This code will work, but is not really correct.  Normally we would hook
+ * vfs_cache_lookup() into vop_lookup_desc and hook pfs_lookup() into
+ * vop_cachedlookup_desc.
  */
 static int
 pfs_lookup(struct vop_lookup_args *va)
@@ -385,6 +394,9 @@ pfs_lookup(struct vop_lookup_args *va)
 	error = pfs_vncache_alloc(vn->v_mount, vpp, pn, pid);
 	if (error)
 		PFS_RETURN (error);
+	/*
+	 * XXX See comment at top of the routine.
+	 */
 	if (cnp->cn_flags & MAKEENTRY)
 		cache_enter(vn, *vpp, cnp);
 	PFS_RETURN (0);
@@ -693,7 +705,7 @@ static int
 pfs_reclaim(struct vop_reclaim_args *va)
 {
 	PFS_TRACE((((struct pfs_vdata *)va->a_vp->v_data)->pvd_pn->pn_name));
-	
+
 	return (pfs_vncache_free(va->a_vp));
 }