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From:   Steve French <smfrench@gmail.com>
Date:   Thu, 21 Oct 2021 18:15:49 -0500
Message-ID: <CAH2r5msO7-QCXv6JQj2Tado9ZoWAHRkgq6-En18PeKSXFDdBLw@mail.gmail.com>
Subject: Re: [PATCH 00/67] fscache: Rewrite index API and management system
To:     Omar Sandoval <osandov@osandov.com>
Cc:     David Howells <dhowells@redhat.com>, linux-cachefs@redhat.com,
        ceph-devel <ceph-devel@vger.kernel.org>,
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On Thu, Oct 21, 2021 at 5:21 PM Omar Sandoval <osandov@osandov.com> wrote:
>
> On Mon, Oct 18, 2021 at 03:50:15PM +0100, David Howells wrote:
> However, with the advent of the tmpfile capacity in the VFS, an opportunity
> arises to do invalidation much more easily, without having to wait for I/O
> that's actually in progress: Cachefiles can simply cut over its file
> pointer for the backing object attached to a cookie and abandon the
> in-progress I/O, dismissing it upon completion.

Have changes been made to O_TMPFILE?  It is problematic for network filesystems
because it is not an atomic operation, and would be great if it were possible
to create a tmpfile and open it atomically (at the file system level).

Currently it results in creating a tmpfile (which results in
opencreate then close)
immediately followed by reopening the tmpfile which is somewhat counter to
the whole idea of a tmpfile (ie that it is deleted when closed) since
the syscall results
in two opens ie open(create)/close/open/close


-- 
Thanks,

Steve