From owner-freebsd-fs@FreeBSD.ORG  Thu Dec 27 22:57:52 2007
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Date: Fri, 28 Dec 2007 09:57:48 +1100 (EST)
From: Bruce Evans <brde@optusnet.com.au>
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To: Raja Sivaramakrishnan <srajag00@yahoo.com>
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Cc: freebsd-fs@FreeBSD.org
Subject: Re: namei lookup vnode locking
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On Thu, 27 Dec 2007, Raja Sivaramakrishnan wrote:

> Thanks for the response - I'll take a look at the handbook.
> Regarding ttywait, it was not called through the ttydrain ioctl.
> ttywait was called through fdfree from exit1() when the login
> process was exiting. I believe this is called with the vnode
> lock held.

Calling device close with the vnode lock held was a large bug.  It was
one of the bugs fixed in 6.2 (devfs_vnops.c 1.114.2.12 2006/10/30 by
kib MFC 1.136 by kib).  It was broken at a higher level by locking the
vnode in vn_close() starting before 6.0 (vfs_vnops.c 1.224 2005/03/13).

Bruce