Add locking around access to parent node, and bail out when the parent

node is already freed rather than panicking the system.

PR:		kern/122038
Submitted by:	gk
Tested by:	pho
MFC after:	1 week

1 files changed, 21 insertions, 1 deletions

diff --git a/sys/fs/tmpfs/tmpfs.h b/sys/fs/tmpfs/tmpfs.h
index ffd705fe026d..1edbc415106b 100644
--- a/sys/fs/tmpfs/tmpfs.h
+++ b/sys/fs/tmpfs/tmpfs.h
@@ -303,10 +303,30 @@ LIST_HEAD(tmpfs_node_list, tmpfs_node);
 
 #define TMPFS_NODE_LOCK(node) mtx_lock(&(node)->tn_interlock)
 #define TMPFS_NODE_UNLOCK(node) mtx_unlock(&(node)->tn_interlock)
-#define        TMPFS_NODE_MTX(node) (&(node)->tn_interlock)
+#define TMPFS_NODE_MTX(node) (&(node)->tn_interlock)
+
+#ifdef INVARIANTS
+#define TMPFS_ASSERT_LOCKED(node) do {					\
+		MPASS(node != NULL);					\
+		MPASS(node->tn_vnode != NULL);				\
+		if (!VOP_ISLOCKED(node->tn_vnode) &&			\
+		    !mtx_owned(TMPFS_NODE_MTX(node)))			\
+			panic("tmpfs: node is not locked: %p", node);	\
+	} while (0)
+#define TMPFS_ASSERT_ELOCKED(node) do {					\
+		MPASS((node) != NULL);					\
+		MPASS((node)->tn_vnode != NULL);			\
+		mtx_assert(TMPFS_NODE_MTX(node), MA_OWNED);		\
+		ASSERT_VOP_LOCKED((node)->tn_vnode, "tmpfs");		\
+	} while (0)
+#else
+#define TMPFS_ASSERT_LOCKED(node) (void)0
+#define TMPFS_ASSERT_ELOCKED(node) (void)0
+#endif
 
 #define TMPFS_VNODE_ALLOCATING	1
 #define TMPFS_VNODE_WANT	2
+#define TMPFS_VNODE_DOOMED	4
 /* --------------------------------------------------------------------- */
 
 /*