Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 13 Mar 2020 09:48:57 -0700
From:   Jeremy Allison <jra@samba.org>
To:     Aleksa Sarai <cyphar@cyphar.com>
Cc:     Stefan Metzmacher <metze@samba.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        David Howells <dhowells@redhat.com>,
        Al Viro <viro@zeniv.linux.org.uk>, Ian Kent <raven@themaw.net>,
        Miklos Szeredi <mszeredi@redhat.com>,
        Christian Brauner <christian@brauner.io>,
        Jann Horn <jannh@google.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Karel Zak <kzak@redhat.com>, jlayton@redhat.com,
        Linux API <linux-api@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LSM List <linux-security-module@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ralph =?iso-8859-1?Q?B=F6hme?= <slow@samba.org>,
        Volker Lendecke <vl@sernet.de>
Subject: Re: [PATCH 01/14] VFS: Add additional RESOLVE_* flags [ver #18]
Message-ID: <20200313164857.GA17682@jeremy-acer>
Reply-To: Jeremy Allison <jra@samba.org>
References: <158376244589.344135.12925590041630631412.stgit@warthog.procyon.org.uk>
 <158376245699.344135.7522994074747336376.stgit@warthog.procyon.org.uk>
 <20200310005549.adrn3yf4mbljc5f6@yavin>
 <CAHk-=wiEBNFJ0_riJnpuUXTO7+_HByVo-R3pGoB_84qv3LzHxA@mail.gmail.com>
 <580352.1583825105@warthog.procyon.org.uk>
 <CAHk-=wiaL6zznNtCHKg6+MJuCqDxO=yVfms3qR9A0czjKuSSiA@mail.gmail.com>
 <3d209e29-e73d-23a6-5c6f-0267b1e669b6@samba.org>
 <CAHk-=wgu3Wo_xcjXnwski7JZTwQFaMmKD0hoTZ=hqQv3-YojSg@mail.gmail.com>
 <8d24e9f6-8e90-96bb-6e98-035127af0327@samba.org>
 <20200313095901.tdv4vl7envypgqfz@yavin>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200313095901.tdv4vl7envypgqfz@yavin>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Mar 13, 2020 at 08:59:01PM +1100, Aleksa Sarai wrote:
> 
> I have heard some folks asking for a way to create a directory and get a
> handle to it atomically -- so arguably this is something that could be
> inside openat2()'s feature set (O_MKDIR?). But I'm not sure how popular
> of an idea this is.

This would be very useful to prevent race conditions between making
a directory and EA's on it, as are needed by Samba for
DOS attributes and Windows/NFSv4 ACLS.