From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 03DE21F942; Mon, 9 Sep 2024 13:01:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725886871; cv=none; b=rbzQI1v4yElcm3ZowFpfj7VYcV9ICitMTtOq+0SVwGEPHejDQfZec25Z7F6/FgFGkQf9NHD2k0+u/TnOGOuyUwMTDRvLm66myco7ug391XOBbISlkp6QzkbR/omLBRKSCZ8cKRDwq4n9bKrRtN5LlVm0+RY1h67UdZVvt7r33Dg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725886871; c=relaxed/simple; bh=LstzvHjrnqTCggL5xnNIDoAEnRl3AQ9Gx2qh2MrSAJg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=N1vnb410hzWdKXKKkcDPmvD2gH+wFKpmKIkglulp+KUkl7rWhgPilcUQuo2wqD4yfzZUfeI9YsaAlNmi/fAsFlWaDspdLeixcOYVLTW/7HgFIXWlixl3EZ7KLnTcCEWjWbhvuXzDhAl/Pgm3THc6cigxjisUIOlFYH2N2Wj2LCA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RSkYCQVb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RSkYCQVb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60F8FC4CEC5; Mon, 9 Sep 2024 13:01:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725886869; bh=LstzvHjrnqTCggL5xnNIDoAEnRl3AQ9Gx2qh2MrSAJg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RSkYCQVb5GNvcIg0Ra+c8oDiO6iLkzV4bOW/eQfdH9mogvsAL/omTfXzWZx7aSRDJ SKA4yaqNHnGgwjox94evLUQr15B8kbJHCJGIISpJc28/LBAqW9K1phD0wmxdtXjChv lCx7wzV4kp1KxZ5HMYAoyoLn6O1dqa65Nb65DY+Iwi4xvOHpdRAi2DDDULpISxSQCM M14rb24lYGi6schqoauiZ9txQH3nRVw8xoUrFVIxZttpDA4VQyoaDprx+1ianiyq+s V3DtQlcx4ihsP3fw4E8TnRC+LKpKFObjgWUeph2mcGqEtrcA9EM6+IhMRA82F2oX+d HkO+9l0Tr2trg== Date: Mon, 9 Sep 2024 15:01:04 +0200 From: Christian Brauner To: Alexander Mikhalitsyn Cc: mszeredi@redhat.com, linux-fsdevel@vger.kernel.org, Miklos Szeredi , Alexander Viro , Jan Kara , Seth Forshee , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 2/3] fs/mnt_idmapping: introduce an invalid_mnt_idmap Message-ID: <20240909-tugend-weiten-13e04fec5f48@brauner> References: <20240906143453.179506-1-aleksandr.mikhalitsyn@canonical.com> <20240906143453.179506-2-aleksandr.mikhalitsyn@canonical.com> <20240909-moosbedeckt-landnahme-61cecf06e530@brauner> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240909-moosbedeckt-landnahme-61cecf06e530@brauner> On Mon, Sep 09, 2024 at 02:57:51PM GMT, Christian Brauner wrote: > On Fri, Sep 06, 2024 at 04:34:52PM GMT, Alexander Mikhalitsyn wrote: > > Link: https://lore.kernel.org/linux-fsdevel/20240904-baugrube-erhoben-b3c1c49a2645@brauner/ > > Suggested-by: Christian Brauner > > Signed-off-by: Alexander Mikhalitsyn > > --- > > fs/mnt_idmapping.c | 22 ++++++++++++++++++++-- > > include/linux/mnt_idmapping.h | 1 + > > 2 files changed, 21 insertions(+), 2 deletions(-) > > > > diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c > > index 3c60f1eaca61..cbca6500848e 100644 > > --- a/fs/mnt_idmapping.c > > +++ b/fs/mnt_idmapping.c > > @@ -32,6 +32,15 @@ struct mnt_idmap nop_mnt_idmap = { > > }; > > EXPORT_SYMBOL_GPL(nop_mnt_idmap); > > > > +/* > > + * Carries the invalid idmapping of a full 0-4294967295 {g,u}id range. > > + * This means that all {g,u}ids are mapped to INVALID_VFS{G,U}ID. > > + */ > > +struct mnt_idmap invalid_mnt_idmap = { > > + .count = REFCOUNT_INIT(1), > > +}; > > +EXPORT_SYMBOL_GPL(invalid_mnt_idmap); > > + > > /** > > * initial_idmapping - check whether this is the initial mapping > > * @ns: idmapping to check > > @@ -75,6 +84,8 @@ vfsuid_t make_vfsuid(struct mnt_idmap *idmap, > > > > if (idmap == &nop_mnt_idmap) > > return VFSUIDT_INIT(kuid); > > + if (idmap == &invalid_mnt_idmap) > > + return INVALID_VFSUID; > > Could possibly deserve an: > > if (unlikely(idmap == &invalid_mnt_idmap)) > return INVALID_VFSUID; > > and technically I guess we could also do: > > if (likely(idmap == &nop_mnt_idmap)) > return VFSUIDT_INIT(kuid); > > but not that relevant for this patch. Forgot: Reviewed-by: Christian Brauner