Module Name: src
Committed By: hannken
Date: Mon Mar 6 10:10:43 UTC 2017
Modified Files:
src/sys/kern: vfs_mount.c
Log Message:
Deny unmounting file systems below layered file systems.
To generate a diff of this commit:
cvs rdiff -u -r1.48 -r1.49 src/sys/kern/vfs_mount.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_mount.c
diff -u src/sys/kern/vfs_mount.c:1.48 src/sys/kern/vfs_mount.c:1.49
--- src/sys/kern/vfs_mount.c:1.48 Wed Feb 22 09:50:13 2017
+++ src/sys/kern/vfs_mount.c Mon Mar 6 10:10:43 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_mount.c,v 1.48 2017/02/22 09:50:13 hannken Exp $ */
+/* $NetBSD: vfs_mount.c,v 1.49 2017/03/06 10:10:43 hannken Exp $ */
/*-
* Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.48 2017/02/22 09:50:13 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.49 2017/03/06 10:10:43 hannken Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -817,6 +817,7 @@ err_unmounted:
int
dounmount(struct mount *mp, int flags, struct lwp *l)
{
+ struct mount *cmp;
vnode_t *coveredvp;
int error, async, used_syncer, used_extattr;
@@ -827,6 +828,18 @@ dounmount(struct mount *mp, int flags, s
#endif /* NVERIEXEC > 0 */
/*
+ * No unmount below layered mounts.
+ */
+ mutex_enter(&mountlist_lock);
+ TAILQ_FOREACH(cmp, &mountlist, mnt_list) {
+ if (cmp->mnt_lower == mp) {
+ mutex_exit(&mountlist_lock);
+ return EBUSY;
+ }
+ }
+ mutex_exit(&mountlist_lock);
+
+ /*
* XXX Freeze syncer. Must do this before locking the
* mount point. See dounmount() for details.
*/
