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From: "J. Bruce Fields" <bfields@fieldses.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: "J. Bruce Fields" <bfields@redhat.com>,
	Oleg Drokin <green@linuxhacker.ru>,
	Jeff Layton <jlayton@poochiereds.net>,
	linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/7] nfsd: remove redundant i_lookup check
Date: Sun, 24 Jul 2016 08:10:14 -0400	[thread overview]
Message-ID: <20160724121014.GA20985@fieldses.org> (raw)
In-Reply-To: <20160724002152.GN2356@ZenIV.linux.org.uk>

On Sun, Jul 24, 2016 at 01:22:06AM +0100, Al Viro wrote:
> On Fri, Jul 22, 2016 at 01:48:52PM -0400, J. Bruce Fields wrote:
> > From: "J. Bruce Fields" <bfields@redhat.com>
> > 
> > I'm not sure why this was added.  It doesn't seem necessary, and no
> > other caller does this.
> 
> lookup_one_len() will explode if you call it for non-directory (==
> !d_can_lookup(), i.e. something without ->lookup()).  So unless the callers
> do guarantee that check being true, it *is* needed.

Both callers call fh_verify(.,.,S_IFDIR,.), so at this point we know
that i_mode & S_IFMT == S_IFDIR.  Is there some odd case where that's
insufficient?  If so, I think there may be bugs elsewhere in nfsd.  If
not, I'll add a note to the changelog.

Thanks for reminding me to check this, I hadn't thought of that as an
"is this a directory" check, it makes more sense now.

--b.

  reply	other threads:[~2016-07-24 12:10 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-08  1:47 [PATCH] nfsd: Make creates return EEXIST correctly instead of EPERM Oleg Drokin
2016-07-08 11:02 ` Jeff Layton
2016-07-08 15:14   ` Oleg Drokin
2016-07-08 15:53     ` Jeff Layton
2016-07-08 15:59       ` Oleg Drokin
2016-07-08 16:17         ` Jeff Layton
2016-07-08 16:28           ` Oleg Drokin
2016-07-09  2:52         ` Al Viro
2016-07-09  2:58           ` Oleg Drokin
2016-07-09  3:13             ` Al Viro
2016-07-08 16:04       ` J. Bruce Fields
2016-07-08 16:16         ` Oleg Drokin
2016-07-08 20:49           ` J. Bruce Fields
2016-07-08 21:47             ` Oleg Drokin
2016-07-09  3:10               ` Al Viro
2016-07-09  3:41                 ` Oleg Drokin
2016-07-13 19:00                   ` J. Bruce Fields
2016-07-08 20:54 ` J. Bruce Fields
2016-07-08 21:53   ` Oleg Drokin
2016-07-21 20:34     ` J. Bruce Fields
2016-07-21 20:37       ` Oleg Drokin
2016-07-22  1:57         ` J. Bruce Fields
2016-07-22  6:35           ` Oleg Drokin
2016-07-22 10:55             ` J. Bruce Fields
2016-07-22 15:13               ` Oleg Drokin
2016-07-22 17:48                 ` J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 1/7] nfsd: Make creates return EEXIST instead of EACCES J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 2/7] nfsd: remove redundant zero-length check from create J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 3/7] nfsd: remove redundant i_lookup check J. Bruce Fields
2016-07-24  0:22                     ` Al Viro
2016-07-24 12:10                       ` J. Bruce Fields [this message]
2016-07-24 14:23                         ` Al Viro
2016-07-24 20:21                           ` J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 4/7] nfsd: reorganize nfsd_create J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 5/7] nfsd: remove unnecessary positive-dentry check J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 6/7] nfsd: clean up bad-type check in nfsd_create_locked J. Bruce Fields
2016-07-22 17:48                   ` [PATCH 7/7] nfsd: drop unnecessary MAY_EXEC check from create J. Bruce Fields

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