[src/trunk]: src/sys/kern Back out sftchg/fstcnt deadlock workaround

[manu <manu%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/325a8da78225
branches:  trunk
changeset: 993846:325a8da78225
user:      manu <manu%NetBSD.org@localhost>
date:      Fri Oct 05 01:25:38 2018 +0000

description:
Back out sftchg/fstcnt deadlock workaround

The change did prevent some system freeze, but caused spurious
unmount failures reporter by bouyer@.

hannken@ is working on the right fix, see kern/53624

diffstat:

 sys/kern/vfs_trans.c |  11 +++--------
 1 files changed, 3 insertions(+), 8 deletions(-)

diffs (42 lines):

diff -r 943bac75fcf2 -r 325a8da78225 sys/kern/vfs_trans.c
--- a/sys/kern/vfs_trans.c      Thu Oct 04 23:53:13 2018 +0000
+++ b/sys/kern/vfs_trans.c      Fri Oct 05 01:25:38 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_trans.c,v 1.49 2018/09/27 01:03:40 manu Exp $      */
+/*     $NetBSD: vfs_trans.c,v 1.50 2018/10/05 01:25:38 manu Exp $      */
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.49 2018/09/27 01:03:40 manu Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.50 2018/10/05 01:25:38 manu Exp $");
 
 /*
  * File system transaction operations.
@@ -42,7 +42,6 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
-#include <sys/kernel.h>
 #include <sys/atomic.h>
 #include <sys/buf.h>
 #include <sys/kmem.h>
@@ -533,14 +532,10 @@
        /*
         * All threads see the new state now.
         * Wait for transactions invalid at this state to leave.
-        * We cannot wait forever because many processes would
-        * get stuck waiting for fstcnt in fstrans_start(). This
-        * is acute when suspending the root filesystem.
         */
        error = 0;
        while (! state_change_done(mp)) {
-               error = cv_timedwait_sig(&fstrans_count_cv,
-                                         &fstrans_lock, hz / 4);
+               error = cv_wait_sig(&fstrans_count_cv, &fstrans_lock);
                if (error) {
                        new_state = fmi->fmi_state = FSTRANS_NORMAL;
                        break;