From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ewsoutbound.kpnmail.nl (ewsoutbound.kpnmail.nl [195.121.94.183]) (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 64B7534040A for ; Wed, 22 Jul 2026 13:27:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.121.94.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784726832; cv=none; b=Gfqqq98XrRAzemfZKH0kFAXUdiut1Y5bMZ2yEUP4QbFZQqtGrAmXMPQGxJgCfQyDJU8gjgedfHL+9rkVJp6BNZ7XkDE9FKYBzigQOnNVYWh2Z19QE+2IuitFaddTRUHW/v7RAF0xvyM4BrztmIDKuy4fWwsUwOENH17IGAK0tm8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784726832; c=relaxed/simple; bh=ThJS8kQC1lyDt7HVuDS3gsyTKZWnYBBr2K9Vr5VYfBk=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: MIME-Version:Content-Type; b=AFh6EpUqHc6AT7T18AqeYEZ36CjKm0mTkXf+tV2Hp/oFUsWziVt0uXjOt1VWKPVc+Sc+ebdBDA/85xQ8he9k/WTNUpsDSXIQ2IUN3BYh3SPPVV/1NBhgSuzfbW42NT3iUC0HJB6cAT9FsWCtVqvnW70RUb96QGWkO5KRkmMjYDQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=xs4all.nl; spf=pass smtp.mailfrom=xs4all.nl; dkim=pass (2048-bit key) header.d=xs4all.nl header.i=@xs4all.nl header.b=RyVAgi6o; arc=none smtp.client-ip=195.121.94.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=xs4all.nl Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=xs4all.nl Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=xs4all.nl header.i=@xs4all.nl header.b="RyVAgi6o" X-KPN-MessageId: 09b941d4-85d1-11f1-8f54-005056992ed3 Received: from mta.kpnmail.nl (unknown [10.31.161.189]) by ewsoutbound.so.kpn.org (Halon) with ESMTPS id 09b941d4-85d1-11f1-8f54-005056992ed3; Wed, 22 Jul 2026 15:27:08 +0200 (CEST) Received: from mtaoutbound.kpnmail.nl (unknown [10.128.135.190]) by mta.kpnmail.nl (Halon) with ESMTP id 09b819cf-85d1-11f1-ae89-0050569981f5; Wed, 22 Jul 2026 15:27:08 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=xs4all.nl; s=xs4all01; h=content-type:mime-version:subject:message-id:to:from:date; bh=34cfnwifCy5RIEQFZMc/WICgSXla8u0z6EY3+zhWjmo=; b=RyVAgi6oNk15xanzeCj7gmpc7EfPLRyNebKiQ49SmB7ouxWMJI2dmesA+8Q5rr0ZS99JZSdGJU8k3 /ktyRYK/PWJfPB28KywiED0b/hbueX0fRiLYeV88fKd1HHc/IGxhcc4Ee47Z+V3U0lhf51RJfvjbYC RaxI96Iet0JRIcas5r02p3/eCdLzejkcSPz5zSBGwfoyRlnfnExOXrDtNGLKOsZne6Ha7cSRQ/q+r0 RRCjwozDFoUATCEq8JT9h5qi+WfYd76MGsIq3vaejFDNWiX479N03P8UG2qAq2ngUqiUYsdTFIouw1 KQfzKd3lX6KiqmMRM0EPjHZikqfSHMw== X-KPN-MID: 33|128Rxe5x9dzzpGjIEuntcbGn7XASwlrAGY+TcLht/MrDO1PFv6asN3Bz2+/sGsr JvOEiyiVfcSERgeSYRDwOEw== X-CMASSUN: 33|rOmBz37bBSKYg4mQQ/qWJ4/bhyyedI03X/flEUlBnfqi3tKXf4NJbzUgs0kZz8G PbhwxG/TG48cIZDHqVqQbzw== X-KPN-VerifiedSender: Yes Received: from cpxoxapps-mh01 (cpxoxapps-mh01.personalcloud.so.kpn.org [10.128.135.207]) by mtaoutbound.kpnmail.nl (Halon) with ESMTPSA id 09ad7b29-85d1-11f1-916a-005056995d6c; Wed, 22 Jul 2026 15:27:08 +0200 (CEST) Date: Wed, 22 Jul 2026 15:27:08 +0200 (CEST) From: Jori Koolstra To: Christoph Hellwig , Christian Brauner Cc: Pedro Falcato , Jeff Layton , Al Viro , Aleksa Sarai , NeilBrown , Amir Goldstein , Jan Kara , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <987276143.170754.1784726828216@kpc.webmail.kpnmail.nl> In-Reply-To: References: <20260704164149.3480051-1-jkoolstra@xs4all.nl> <20260704164149.3480051-10-jkoolstra@xs4all.nl> <20260707-vorteil-unhaltbar-apotheke-47bb105161ff@brauner> <20260722-mundpropaganda-vorwahl-funkverkehr-48efdde92a00@brauner> Subject: Re: [PATCH v3 09/14] vfs: add O_CREAT|O_DIRECTORY to open*(2) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Priority: 3 Importance: Normal > Op 22-07-2026 15:10 CEST schreef Christoph Hellwig : > > > On Wed, Jul 22, 2026 at 02:51:54PM +0200, Christian Brauner wrote: > > > No, we can't rely on something being backport to old enterprise/cloud > > > kernel. Doing so makes the interface unusable for actual applications. > > > > It's backported to all LTS kernels for multiple years and this > > nonsensical theory of using a software version with O_DIRECTORY | > > O_CREAT on a pre-LTS kernel from years ago is just flimsy. > > the kernel has always ignored unknown open flags, or unchecked > combinations and you can't just silently give them a meaning unless > it is backwars compatible. That has nothing to do with this particular > combination. > > > > > Even just the mere fact that I was able to just backport that bugfix > > that started returning hard errors to all LTS kernels with absolutely > > zero regression reports defeats that argument. We've done way more > > invasive changes. This is a strawman really. > > Of course it didn't break anything yet because no one used it yet. > One we give it a meaning it will be used and break. And if you like > it or not, a lot o Linux deployment is not using recent stable releases > or even tracking the -stable releases at all. > If you want your software to be compatible with any Frankenstein-kernel you just check what you O_CREATed is in fact a directory. If it is and there is no EINVAL/EISDIR, you are running a supported kernel, if it isn't, you're not. Or you just require a minimal reasonable kernel version. > Just like we've always done in the past we'll need to APIs that don't > accidentally do the wrong thing on any old kernel. We've survived doing > it this way the last 25 years (maybe longer, but that's about how long > I've been around) and there is no reason to magically change this now.