Add dedicated routines to toggle lockmgr flags such as LK_NOSHARE and

LK_CANRECURSE after a lock is created.  Use them to implement macros that
otherwise manipulated the flags directly.  Assert that the associated
lockmgr lock is exclusively locked by the current thread when manipulating
these flags to ensure the flag updates are safe.  This last change required
some minor shuffling in a few filesystems to exclusively lock a brand new
vnode slightly earlier.

Reviewed by:	kib
MFC after:	3 days

1 files changed, 3 insertions, 4 deletions

diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
index 5b6ccf6..e0684b1 100644
--- a/sys/kern/vfs_lookup.c
+++ b/sys/kern/vfs_lookup.c
@@ -84,14 +84,13 @@ static struct vnode *vp_crossmp;
 static void
 nameiinit(void *dummy __unused)
 {
-	int error;
 
 	namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL,
 	    UMA_ALIGN_PTR, 0);
-	error = getnewvnode("crossmp", NULL, &dead_vnodeops, &vp_crossmp);
-	if (error != 0)
-		panic("nameiinit: getnewvnode");
+	getnewvnode("crossmp", NULL, &dead_vnodeops, &vp_crossmp);
+	vn_lock(vp_crossmp, LK_EXCLUSIVE);
 	VN_LOCK_ASHARE(vp_crossmp);
+	VOP_UNLOCK(vp_crossmp, 0);
 }
 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL);