[src/trunk]: src/sys/kern Destroy anonymous device vnodes on reboot once the ...

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

details:   https://anonhg.NetBSD.org/src/rev/dff5124a035b
branches:  trunk
changeset: 971245:dff5124a035b
user:      hannken <hannken%NetBSD.org@localhost>
date:      Sun Apr 19 13:26:17 2020 +0000

description:
Destroy anonymous device vnodes on reboot once the last file system
got unmounted and the mount list is empty.

PR kern/54969: Disk cache is no longer flushed on shutdown

diffstat:

 sys/kern/vfs_mount.c |  25 +++++++++++++++++++++++--
 1 files changed, 23 insertions(+), 2 deletions(-)

diffs (60 lines):

diff -r 8d3d9e588852 -r dff5124a035b sys/kern/vfs_mount.c
--- a/sys/kern/vfs_mount.c      Sun Apr 19 13:25:00 2020 +0000
+++ b/sys/kern/vfs_mount.c      Sun Apr 19 13:26:17 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_mount.c,v 1.78 2020/04/13 19:23:18 ad Exp $        */
+/*     $NetBSD: vfs_mount.c,v 1.79 2020/04/19 13:26:17 hannken Exp $   */
 
 /*-
  * Copyright (c) 1997-2020 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.78 2020/04/13 19:23:18 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.79 2020/04/19 13:26:17 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -115,6 +115,8 @@
 /* Root filesystem. */
 vnode_t *                      rootvnode;
 
+extern struct mount            *dead_rootmount;
+
 /* Mounted filesystem list. */
 static TAILQ_HEAD(mountlist, mountlist_entry) mountlist;
 static kmutex_t                        mountlist_lock __cacheline_aligned;
@@ -1020,6 +1022,7 @@
 vfs_unmountall1(struct lwp *l, bool force, bool verbose)
 {
        struct mount *mp;
+       mount_iterator_t *iter;
        bool any_error = false, progress = false;
        uint64_t gen;
        int error;
@@ -1054,6 +1057,24 @@
        if (any_error && verbose) {
                printf("WARNING: some file systems would not unmount\n");
        }
+
+       /* If the mountlist is empty destroy anonymous device vnodes. */
+       mountlist_iterator_init(&iter);
+       if (mountlist_iterator_next(iter) == NULL) {
+               struct vnode_iterator *marker;
+               vnode_t *vp;
+
+               vfs_vnode_iterator_init(dead_rootmount, &marker);
+               while ((vp = vfs_vnode_iterator_next(marker, NULL, NULL))) {
+                       if (vp->v_type == VCHR || vp->v_type == VBLK)
+                               vgone(vp);
+                       else
+                               vrele(vp);
+               }
+               vfs_vnode_iterator_destroy(marker);
+       }
+       mountlist_iterator_destroy(iter);
+
        return progress;
 }