From owner-freebsd-hackers  Fri Jan 10 14:36:31 2003
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Message-ID: <3E1F4944.96F1AD23@mindspring.com>
Date: Fri, 10 Jan 2003 14:29:24 -0800
From: Terry Lambert <tlambert2@mindspring.com>
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To: Richard Sharpe <rsharpe@richardsharpe.com>
Cc: freebsd-hackers@freebsd.org
Subject: Re: What prevents there from being a race with open(...,O_CREAT 
 |O_EXCL,...)
References: <Pine.LNX.4.33.0301101437330.2747-100000@ns.aus.com>
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Richard Sharpe wrote:
> In looking at vn_open, I see that it calls namei and then a little while
> later calls VOP_CREATE.
> 
> If the user did open(..., ... O_CREAT | O_EXCL, ...), what prevents a race
> where one process discovers that the name doesn't already exist but
> another gets in and creates the name?

The directory vnode is locked over the create operation.

-- Terry

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