linux-kernel - Re: [PATCH 4/7] autofs4 - fix indirect mount pending expire race

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Message-ID: <x49ljzzc8e1.fsf@segfault.boston.devel.redhat.com>
Date:	Fri, 18 Jul 2008 15:14:14 -0400
From:	Jeff Moyer <jmoyer@...hat.com>
To:	Ian Kent <raven@...maw.net>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	autofs mailing list <autofs@...ux.kernel.org>,
	Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	Al Viro <viro@...IV.linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 4/7] autofs4 - fix indirect mount pending expire race

Ian Kent <raven@...maw.net> writes:

> On Fri, 2008-07-18 at 14:52 -0400, Jeff Moyer wrote:
>> Ian Kent <raven@...maw.net> writes:
>> >  		} else {
>> > +			/* Path walk currently on this dentry? */
>> > +			ino_count = atomic_read(&ino->count) + 1;
>> > +			if (atomic_read(&dentry->d_count) > ino_count)
>> > +				goto next;
>> > +
>> >  			expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
>> >  			if (expired) {
>> >  				dput(dentry);
>
> The expired dentry may be a different dentry!
>
>> >  found:
>> >  	DPRINTK("returning %p %.*s",
>> >  		expired, (int)expired->d_name.len, expired->d_name.name);
>> > +	ino = autofs4_dentry_ino(expired);
>> 
>> If we get here, ino is already set to the autofs4_dentry_ino(expired),
>> so this statement is redundant.
>
> Almost but see above.

Ah, you're right, I missed that.

Cheers,

Jeff
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