svn commit: r253158 - in head/sys: kern sys

[Marcel Moolenaar]

Author: marcel
Date: Wed Jul 10 15:35:25 2013
New Revision: 253158
URL: http://svnweb.freebsd.org/changeset/base/253158

Log:
  Add vfs_mounted and vfs_unmounted events so that components can be informed
  about mount and unmount events. This is used by Juniper to implement a more
  optimal implementation of NetBSD's veriexec.
  
  This change differs from r253224 in the following way:
  o   The vfs_mounted handler is called before mountcheckdirs() and with
      newdp locked. vp is unlocked.
  o   The event handlers are declared in <sys/eventhandler.h> and not in
      <sys/mount.h>. The <sys/mount.h> header is used in user land code
      that pretends to be kernel code and as such creates a very convoluted
      environment. It's hard to untangle.
  
  Submitted by:	stevek at juniper.net
  Discussed with:	pjd@
  Obtained from:	Juniper Networks, Inc.

Modified:
  head/sys/kern/vfs_mount.c
  head/sys/sys/eventhandler.h

Modified: head/sys/kern/vfs_mount.c
==============================================================================
--- head/sys/kern/vfs_mount.c	Wed Jul 10 14:16:39 2013	(r253157)
+++ head/sys/kern/vfs_mount.c	Wed Jul 10 15:35:25 2013	(r253158)
@@ -861,8 +861,9 @@ vfs_domount_first(
 	vfs_event_signal(NULL, VQ_MOUNT, 0);
 	if (VFS_ROOT(mp, LK_EXCLUSIVE, &newdp))
 		panic("mount: lost mount");
-	VOP_UNLOCK(newdp, 0);
 	VOP_UNLOCK(vp, 0);
+	EVENTHANDLER_INVOKE(vfs_mounted, mp, newdp, td);
+	VOP_UNLOCK(newdp, 0);
 	mountcheckdirs(vp, newdp);
 	vrele(newdp);
 	if ((mp->mnt_flag & MNT_RDONLY) == 0)
@@ -1355,6 +1356,7 @@ dounmount(mp, flags, td)
 	mtx_lock(&mountlist_mtx);
 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
 	mtx_unlock(&mountlist_mtx);
+	EVENTHANDLER_INVOKE(vfs_unmounted, mp, td);
 	if (coveredvp != NULL) {
 		coveredvp->v_mountedhere = NULL;
 		vput(coveredvp);

Modified: head/sys/sys/eventhandler.h
==============================================================================
--- head/sys/sys/eventhandler.h	Wed Jul 10 14:16:39 2013	(r253157)
+++ head/sys/sys/eventhandler.h	Wed Jul 10 15:35:25 2013	(r253158)
@@ -192,6 +192,17 @@ EVENTHANDLER_DECLARE(vm_lowmem, vm_lowme
 typedef void (*mountroot_handler_t)(void *);
 EVENTHANDLER_DECLARE(mountroot, mountroot_handler_t);
 
+/* File system mount events */
+struct mount;
+struct vnode;
+struct thread;
+typedef void (*vfs_mounted_notify_fn)(void *, struct mount *, struct vnode *,
+    struct thread *);
+typedef void (*vfs_unmounted_notify_fn)(void *, struct mount *,
+    struct thread *);
+EVENTHANDLER_DECLARE(vfs_mounted, vfs_mounted_notify_fn);
+EVENTHANDLER_DECLARE(vfs_unmounted, vfs_unmounted_notify_fn);
+
 /* VLAN state change events */
 struct ifnet;
 typedef void (*vlan_config_fn)(void *, struct ifnet *, uint16_t);
@@ -231,7 +242,6 @@ EVENTHANDLER_DECLARE(process_exec, execl
 /*
  * application dump event
  */
-struct thread;
 typedef void (*app_coredump_start_fn)(void *, struct thread *, char *name);
 typedef void (*app_coredump_progress_fn)(void *, struct thread *td, int byte_count);
 typedef void (*app_coredump_finish_fn)(void *, struct thread *td);