Index: sys/fs/tmpfs/tmpfs_subr.c
===================================================================
--- sys/fs/tmpfs/tmpfs_subr.c
+++ sys/fs/tmpfs/tmpfs_subr.c
@@ -361,6 +361,57 @@
 	return (1);
 }
 
+static int
+tmpfs_partial_page_invalidate(vm_object_t object, vm_pindex_t idx, int base,
+    int end, boolean_t ignerr)
+{
+	vm_page_t m;
+	int rv;
+
+	VM_OBJECT_ASSERT_WLOCKED(object);
+	KASSERT(base >= 0, ("%s: base %d", __func__, base));
+	KASSERT(end - base <= PAGE_SIZE, ("%s: base %d end %d", __func__, base,
+	    end));
+
+retry:
+	m = vm_page_grab(object, idx, VM_ALLOC_NOCREAT);
+	if (m != NULL) {
+		MPASS(vm_page_all_valid(m));
+	} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
+		m = vm_page_alloc(object, idx, VM_ALLOC_NORMAL |
+		    VM_ALLOC_WAITFAIL);
+		if (m == NULL)
+			goto retry;
+		vm_object_pip_add(object, 1);
+		VM_OBJECT_WUNLOCK(object);
+		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
+		VM_OBJECT_WLOCK(object);
+		vm_object_pip_wakeup(object);
+		if (rv == VM_PAGER_OK) {
+			/*
+			 * Since the page was not resident, and therefore not
+			 * recently accessed, immediately enqueue it for
+			 * asynchronous laundering.  The current operation is
+			 * not regarded as an access.
+			 */
+			vm_page_launder(m);
+		} else {
+			vm_page_free(m);
+			if (ignerr)
+				m = NULL;
+			else
+				return (EIO);
+		}
+	}
+	if (m != NULL) {
+		pmap_zero_page_area(m, base, end - base);
+		vm_page_set_dirty(m);
+		vm_page_xunbusy(m);
+	}
+
+	return (0);
+}
+
 void
 tmpfs_ref_node(struct tmpfs_node *node)
 {
@@ -1662,7 +1713,6 @@
 	struct tmpfs_mount *tmp;
 	struct tmpfs_node *node;
 	vm_object_t uobj;
-	vm_page_t m;
 	vm_pindex_t idx, newpages, oldpages;
 	off_t oldsize;
 	int base, rv;
@@ -1702,45 +1752,11 @@
 		base = newsize & PAGE_MASK;
 		if (base != 0) {
 			idx = OFF_TO_IDX(newsize);
-retry:
-			m = vm_page_grab(uobj, idx, VM_ALLOC_NOCREAT);
-			if (m != NULL) {
-				MPASS(vm_page_all_valid(m));
-			} else if (vm_pager_has_page(uobj, idx, NULL, NULL)) {
-				m = vm_page_alloc(uobj, idx, VM_ALLOC_NORMAL |
-				    VM_ALLOC_WAITFAIL);
-				if (m == NULL)
-					goto retry;
-				vm_object_pip_add(uobj, 1);
+			rv = tmpfs_partial_page_invalidate(uobj, idx, base,
+			    PAGE_SIZE, ignerr);
+			if (rv != 0) {
 				VM_OBJECT_WUNLOCK(uobj);
-				rv = vm_pager_get_pages(uobj, &m, 1, NULL,
-				    NULL);
-				VM_OBJECT_WLOCK(uobj);
-				vm_object_pip_wakeup(uobj);
-				if (rv == VM_PAGER_OK) {
-					/*
-					 * Since the page was not resident,
-					 * and therefore not recently
-					 * accessed, immediately enqueue it
-					 * for asynchronous laundering.  The
-					 * current operation is not regarded
-					 * as an access.
-					 */
-					vm_page_launder(m);
-				} else {
-					vm_page_free(m);
-					if (ignerr)
-						m = NULL;
-					else {
-						VM_OBJECT_WUNLOCK(uobj);
-						return (EIO);
-					}
-				}
-			}
-			if (m != NULL) {
-				pmap_zero_page_area(m, base, PAGE_SIZE - base);
-				vm_page_set_dirty(m);
-				vm_page_xunbusy(m);
+				return (rv);
 			}
 		}