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Modify vn_lock(): 

- Take v_interlock before examining v_iflag
- Must always be called without v_interlock taken,
  LK_INTERLOCK flag is no longer allowed.
This commit is contained in:
hannken 2010-07-28 09:30:21 +00:00
parent 5112be368f
commit 2ac44efee2
1 changed files with 7 additions and 15 deletions
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22
sys/kern/vfs_vnops.c
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@ -1,4 +1,4 @@
/* $NetBSD: vfs_vnops.c,v 1.175 2010/07/13 15:38:15 pooka Exp $ */
/* $NetBSD: vfs_vnops.c,v 1.176 2010/07/28 09:30:21 hannken Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.175 2010/07/13 15:38:15 pooka Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.176 2010/07/28 09:30:21 hannken Exp $");
#include "veriexec.h"
@ -770,12 +770,10 @@ vn_lock(struct vnode *vp, int flags)
int error;
#if 0
KASSERT(vp->v_usecount > 0 || (flags & LK_INTERLOCK) != 0
|| (vp->v_iflag & VI_ONWORKLST) != 0);
KASSERT(vp->v_usecount > 0 || (vp->v_iflag & VI_ONWORKLST) != 0);
#endif
KASSERT((flags &
~(LK_INTERLOCK|LK_SHARED|LK_EXCLUSIVE|LK_NOWAIT|LK_RETRY))
== 0);
KASSERT((flags & ~(LK_SHARED|LK_EXCLUSIVE|LK_NOWAIT|LK_RETRY)) == 0);
KASSERT(!mutex_owned(&vp->v_interlock));
#ifdef DIAGNOSTIC
if (wapbl_vphaswapbl(vp))
@ -787,11 +785,8 @@ vn_lock(struct vnode *vp, int flags)
* XXX PR 37706 forced unmount of file systems is unsafe.
* Race between vclean() and this the remaining problem.
*/
mutex_enter(&vp->v_interlock);
if (vp->v_iflag & VI_XLOCK) {
if ((flags & LK_INTERLOCK) == 0) {
mutex_enter(&vp->v_interlock);
}
flags &= ~LK_INTERLOCK;
if (flags & LK_NOWAIT) {
mutex_exit(&vp->v_interlock);
return EBUSY;
@ -800,10 +795,7 @@ vn_lock(struct vnode *vp, int flags)
mutex_exit(&vp->v_interlock);
error = ENOENT;
} else {
if ((flags & LK_INTERLOCK) != 0) {
mutex_exit(&vp->v_interlock);
}
flags &= ~LK_INTERLOCK;
mutex_exit(&vp->v_interlock);
error = VOP_LOCK(vp, (flags & ~LK_RETRY));
if (error == 0 || error == EDEADLK || error == EBUSY)
return (error);