Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 15 Jun 2020 14:57:01 +0200
From:   David Sterba <dsterba@suse.cz>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     David Sterba <dsterba@suse.com>,
        linux-btrfs <linux-btrfs@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] Btrfs updates for 5.8, part 2
Message-ID: <20200615125701.GY27795@twin.jikos.cz>
Reply-To: dsterba@suse.cz
Mail-Followup-To: dsterba@suse.cz,
        Linus Torvalds <torvalds@linux-foundation.org>,
        David Sterba <dsterba@suse.com>,
        linux-btrfs <linux-btrfs@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <cover.1592135316.git.dsterba@suse.com>
 <CAHk-=whbO-6zmwfQaX2=cDfsq_sN1PZ6_CAbqLgw3DUptnFrPg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAHk-=whbO-6zmwfQaX2=cDfsq_sN1PZ6_CAbqLgw3DUptnFrPg@mail.gmail.com>
User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sun, Jun 14, 2020 at 09:50:17AM -0700, Linus Torvalds wrote:
> On Sun, Jun 14, 2020 at 4:56 AM David Sterba <dsterba@suse.com> wrote:
> >
> > Reverts are not great, but under current circumstances I don't see
> > better options.
> 
> Pulled. Are people discussing how to make iomap work for everybody?
> It's a bit sad if we can't have the major filesystems move away from
> the old buffer head interfaces to a common more modern one..

Yes, it's fixable and we definitely want to move to iomap. The direct to
buffered fallback would fix one of the problems, but this would also
mean that xfs would start doing that. Such change should be treated more
like a feature development than a bugfix, imposed by another filesystem,
and xfs people rightfully complained.

It's quite possible that there's a better way to fix it on the iomap API
level but I haven't looked into that yet. We get support from iomap
people to add what we need for btrfs, so it's just a matter of time and
testing.