Subject: Re: [PATCH 03/11] VFS: Add security label support to *notify
From: Dave Quigley <dpquigl@tycho.nsa.gov>
To: "Josef 'Jeff' Sipek" <jeffpc@josefsipek.net>
Cc: hch@infradead.org, viro@ftp.linux.org.uk, trond.myklebust@fys.uio.no,
       bfields@fieldses.org, linux-kernel@vger.kernel.org,
       linux-fsdevel@vger.kernel.org
In-Reply-To: <20080228211531.GE32351@josefsipek.net>
References: <1204144786-3502-1-git-send-email-dpquigl@tycho.nsa.gov>
	 <1204144786-3502-4-git-send-email-dpquigl@tycho.nsa.gov>
	 <20080228201004.GC32351@josefsipek.net>
	 <1204231170.24345.100.camel@moss-terrapins.epoch.ncsc.mil>
	 <20080228211531.GE32351@josefsipek.net>
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Date: Thu, 28 Feb 2008 16:05:11 -0500
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On Thu, 2008-02-28 at 16:15 -0500, Josef 'Jeff' Sipek wrote:
> On Thu, Feb 28, 2008 at 03:39:30PM -0500, Dave Quigley wrote:
> ...
> > > Alright...so, few things...
> > > 
> > > 1) why do you need the locked/unlocked versions?
> > > 
> > > 2) instead of passing a flag to a common function, why not have:
> > > 
> > > vfs_setxattr_locked(....)
> > > {
> > > 	// original code minus the lock/unlock calls
> > > }
> > > 
> > > vfs_setxattr(....)
> > > {
> > > 	mutex_lock(...);
> > > 	vfs_setxattr_locked(...);
> > > 	mutex_unlock(...);
> > > }
> > 
> > What we do and what you propose aren't logically equivalent. There is a
> > permission check inside vfs_setxattr before the mutex lock.
> 
> Ah, right. I didn't notice the @@ line...
> 
> Josef 'Jeff' Sipek.
> 

I'm compiling a test kernel with your proposed change to make sure it
doesn't deadlock. If it works then I'll go with your solution since its
less messy.

Dave

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