Switch from just holding the interlock to holding the standard lock throughout

getnewvnode().  This is safer.  In the future, we should investigate requiring
only the interlock to get the vnode object.

1 files changed, 17 insertions, 12 deletions

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 6e7a68c..8ec7885 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -772,23 +772,27 @@ getnewvnode(tag, mp, vops, vpp)
 				panic("getnewvnode: free vnode isn't");
 			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
 
-			if (vn_lock(vp, LK_EXCLUSIVE, td) != 0)
+			/* Don't recycle if we can't get the interlock */
+			if (!mtx_trylock(&vp->v_interlock)) {
+				vp = NULL;
+				continue;
+			}
+
+			/* We should be able to immediately acquire this */
+			if (vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE, td) != 0)
 				continue;
 			/*
-			 * Don't recycle if we still have cached pages or if
-			 * we cannot get the interlock.
+			 * Don't recycle if we still have cached pages.
 			 */
-			if ((VOP_GETVOBJECT(vp, &object) == 0 &&
+			if (VOP_GETVOBJECT(vp, &object) == 0 &&
 			     (object->resident_page_count ||
-			      object->ref_count)) ||
-			     !mtx_trylock(&vp->v_interlock)) {
+			      object->ref_count)) { 
 				TAILQ_INSERT_TAIL(&vnode_free_list, vp,
 						    v_freelist);
 				vp = NULL;
 				VOP_UNLOCK(vp, 0, td);
 				continue;
 			}
-			VOP_UNLOCK(vp, 0, td);
 			if (LIST_FIRST(&vp->v_cache_src)) {
 				/*
 				 * note: nameileafonly sysctl is temporary,
@@ -802,7 +806,7 @@ getnewvnode(tag, mp, vops, vpp)
 					 * subdirectories.
 					 */
 					if (cache_leaf_test(vp) < 0) {
-						mtx_unlock(&vp->v_interlock);
+						VOP_UNLOCK(vp, 0, td);
 						TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 						vp = NULL;
 						continue;
@@ -816,7 +820,7 @@ getnewvnode(tag, mp, vops, vpp)
 					 * turned off (otherwise we reuse them
 					 * too quickly).
 					 */
-					mtx_unlock(&vp->v_interlock);
+					VOP_UNLOCK(vp, 0, td);
 					TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 					vp = NULL;
 					continue;
@@ -827,7 +831,7 @@ getnewvnode(tag, mp, vops, vpp)
 			 */
 			if (vn_start_write(vp, &vnmp, V_NOWAIT) == 0)
 				break;
-			mtx_unlock(&vp->v_interlock);
+			VOP_UNLOCK(vp, 0, td);
 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 			vp = NULL;
 		}
@@ -839,9 +843,10 @@ getnewvnode(tag, mp, vops, vpp)
 		mtx_unlock(&vnode_free_list_mtx);
 		cache_purge(vp);
 		if (vp->v_type != VBAD) {
-			vgonel(vp, td);
+			VOP_UNLOCK(vp, 0, td);
+			vgone(vp);
 		} else {
-			mtx_unlock(&vp->v_interlock);
+			VOP_UNLOCK(vp, 0, td);
 		}
 		vn_finished_write(vnmp);