[src/trunk]: src/sys/uvm When turning off swap during reboot we have to lock ...

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

details:   https://anonhg.NetBSD.org/src/rev/8ea4456ae64b
branches:  trunk
changeset: 952829:8ea4456ae64b
user:      hannken <hannken%NetBSD.org@localhost>
date:      Fri Feb 19 13:20:43 2021 +0000

description:
When turning off swap during reboot we have to lock with LK_RETRY
as regular files got reclaimed during unmount.

Adresses PR kern/54969 (Disk cache is no longer flushed on shutdown)

diffstat:

 sys/uvm/uvm_swap.c |  17 +++++++----------
 1 files changed, 7 insertions(+), 10 deletions(-)

diffs (38 lines):

diff -r f543450d7d1c -r 8ea4456ae64b sys/uvm/uvm_swap.c
--- a/sys/uvm/uvm_swap.c        Fri Feb 19 12:28:56 2021 +0000
+++ b/sys/uvm/uvm_swap.c        Fri Feb 19 13:20:43 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_swap.c,v 1.201 2021/02/16 09:56:32 hannken Exp $   */
+/*     $NetBSD: uvm_swap.c,v 1.202 2021/02/19 13:20:43 hannken Exp $   */
 
 /*
  * Copyright (c) 1995, 1996, 1997, 2009 Matthew R. Green
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.201 2021/02/16 09:56:32 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.202 2021/02/19 13:20:43 hannken Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_compat_netbsd.h"
@@ -1155,14 +1155,11 @@
                        printf("\nturning off swap on %s...", sdp->swd_path);
 #endif
                        /* Have to lock and reference vnode for swap_off(). */
-                       if (vn_lock(vp = sdp->swd_vp, LK_EXCLUSIVE)) {
-                               error = EBUSY;
-                       } else {
-                               vref(vp);
-                               error = swap_off(l, sdp);
-                               vput(vp);
-                               mutex_enter(&uvm_swap_data_lock);
-                       }
+                       vn_lock(vp = sdp->swd_vp, LK_EXCLUSIVE|LK_RETRY);
+                       vref(vp);
+                       error = swap_off(l, sdp);
+                       vput(vp);
+                       mutex_enter(&uvm_swap_data_lock);
                        if (error) {
                                printf("stopping swap on %s failed "
                                    "with error %d\n", sdp->swd_path, error);