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 04EEE13A242; Tue, 28 May 2024 12:04:21 +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=1716897862; cv=none; b=B+HX6jVlnlajYtIZ5qwJ/a37UOsFYopdgirouU31nZ/FR5UWM6gAyGqKC0h8ERq1ggMXJfgGh2CbripRUxVgjv76U7nh6sb59QodOgfJf1wf2dqKVbh0sjpDum4vKk0MfGaZN7tC/fsR6gPoZP3bZR8vGHPC+iZccqgU8T4YBh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716897862; c=relaxed/simple; bh=58egx2ps+6Wd1SWHNZP2itAP+QAyWA4OV5HwePJdVbY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rBgtR9SehTIWMbB59T/tJwkanzocgAla0OG8Eysi/qbpARcoCIv9exjuVWhI9lkvZRZ+C8G+meI5337BHZc4apNbYiR1uWmldy6IgpdNU2LqtJuOMe5AZL9Sv+sceVyQmp0B2X+rodqQdncIKMnKegR1A97eL5yPiTjAxCVcJAk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dG/8WVC0; 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="dG/8WVC0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88CA4C3277B; Tue, 28 May 2024 12:04:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716897861; bh=58egx2ps+6Wd1SWHNZP2itAP+QAyWA4OV5HwePJdVbY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dG/8WVC00ObIsjXJb4Rbw4GYINkQAmvMhB+ACGZyZPnoB3/5W17IxpBbpRhLMH/Zt RYKOYgWMBur6TREpatnG8wplU6AoVFE98XARvDOmb43Qb+6tZdtrfNyu0/P6kIz8au c+rz3CsefuHcMmUDeaf3FmgKn86NOHJ4aKsNGzIceAAFGpJqRkFFI5/rID5S31ortM B8WbdEi6TkVmwyfZwDexHs5Q7hr0Glk7Piwul4Wl6pxq3R4yOeW251LE90IrJTDdNd YHKmSEmphEyaIUZfA302dT0s6MS5hU6ijm7HwddSKztskCa0cS7q9GIVPNL2F62t6w A9PthY+zBZStw== Date: Tue, 28 May 2024 14:04:16 +0200 From: Christian Brauner To: Christoph Hellwig Cc: Jan Kara , Aleksa Sarai , Alexander Viro , Chuck Lever , Jeff Layton , Amir Goldstein , Alexander Aring , linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH RFC v2] fhandle: expose u64 mount id to name_to_handle_at(2) Message-ID: <20240528-gipfel-dilemma-948a590a36fd@brauner> References: <20240523-exportfs-u64-mount-id-v2-1-f9f959f17eb1@cyphar.com> <20240526.184753-detached.length.shallow.contents-jWkMukeD7VAC@cyphar.com> <20240527133430.ifjo2kksoehtuwrn@quack3> <20240528-wachdienst-weitreichend-42f8121bf764@brauner> <20240528-gesell-evakuieren-899c08cbfa06@brauner> Precedence: bulk X-Mailing-List: linux-api@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: On Tue, May 28, 2024 at 03:55:29AM -0700, Christoph Hellwig wrote: > On Tue, May 28, 2024 at 11:17:58AM +0200, Christian Brauner wrote: > > As I've said earlier, independent of the new handle type returning the > > new mount id is useful and needed because it allows the caller to > > reliably generate a mount fd for use with open_by_handle_at() via > > statmount(). That won't be solved by a new handle type and is racy with > > the old mount id. So I intend to accept a version of this patch. > > The whole point is that with the fsid in the handle we do not even need > a mount fd for open_by_handle_at. Can you please explain how opening an fd based on a handle returned from name_to_handle_at() and not using a mount file descriptor for open_by_handle_at() would work?