On Jul 2, 2006, at 2:22 AM, Juergen Hannken-Illjes wrote:

> Could we agree on the attached diff?  Compiled but not tested so far.


Index: sys/kern/kern_exit.c
===================================================================
RCS file: /cvsroot/src/sys/kern/kern_exit.c,v
retrieving revision 1.156
diff -p -u -4 -r1.156 kern_exit.c
--- sys/kern/kern_exit.c	14 May 2006 21:15:11 -0000	1.156
+++ sys/kern/kern_exit.c	2 Jul 2006 09:05:12 -0000
@@ -350,8 +350,10 @@ exit1(struct lwp *l, int rv)
	 */
#ifndef __NO_CPU_LWP_FREE
	cpu_lwp_free(l, 1);
#endif
+	if (l->l_vntrans)
+		vn_trans_destroy(l);
	pmap_deactivate(l);
	/*

I'd say just always call vn_trans_destroy() and let it handle the  
NULL case.



+int
+vn_trans_lock(struct mount *mp, int flags)
+{
+	int error, pflags;
+	struct vn_trans_entry *vte, *new_vte;
+
+	KASSERT((flags & ~(LK_SHARED|LK_EXCLUSIVE|LK_NOWAIT)) == 0);


I'd say make new vn_trans-specific flags and internally translate to  
lockmgr().  Let's not propagate the lockmgr() interface any further,  
please :-)



+void
+vn_trans_unlock(struct mount *mp)
+{
+	struct vn_trans_entry *vte;
+
+	if (mp == NULL)
+		return;
+	if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0)
+		return;
+
+	for (vte = curlwp->l_vntrans; vte; vte = vte->vte_succ) {
+		if (vte->vte_mount == mp) {
+			vte->vte_count -= 1;
+			if (vte->vte_count > 0)
+				return;
+			break;
+		}
+	}


Any reason not to KASSERT() the desired desired transaction is the  
first on the list?  Nested transactions should always be released in  
LIFO order, yes?


I also would say the names of the functions should be changed as so:

vn_trans_destroy() -> fstrans_exit()

vn_trans_lock() -> fstrans_start()

vn_trans_unlock() -> fstrans_done()

it's really file systems you're operating on, not vnodes.

Also, I'd say put the new routines in kern/vfs_trans.c

-- thorpej