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Date:   Fri, 21 Jul 2023 08:20:56 +1000
From:   Dave Chinner <david@fromorbit.com>
To:     Jeff Layton <jlayton@kernel.org>
Cc:     Matthew Wilcox <willy@infradead.org>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
        Dmitry Vyukov <dvyukov@google.com>,
        Viacheslav Dubeyko <slava@dubeyko.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        syzbot <syzbot+7bb7cd3595533513a9e7@syzkaller.appspotmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        christian.brauner@ubuntu.com,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com,
        ZhangPeng <zhangpeng362@huawei.com>,
        linux-m68k@lists.linux-m68k.org,
        debian-ports <debian-ports@lists.debian.org>
Subject: Re: [syzbot] [hfs?] WARNING in hfs_write_inode
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On Thu, Jul 20, 2023 at 02:27:50PM -0400, Jeff Layton wrote:
> On Thu, 2023-07-20 at 18:59 +0100, Matthew Wilcox wrote:
> > On Thu, Jul 20, 2023 at 07:50:47PM +0200, John Paul Adrian Glaubitz wrote:
> > > > Then we should delete the HFS/HFS+ filesystems.  They're orphaned in
> > > > MAINTAINERS and if distros are going to do such a damnfool thing,
> > > > then we must stop them.
> > > 
> > > Both HFS and HFS+ work perfectly fine. And if distributions or users are so
> > > sensitive about security, it's up to them to blacklist individual features
> > > in the kernel.
> > > 
> > > Both HFS and HFS+ have been the default filesystem on MacOS for 30 years
> > > and I don't think it's justified to introduce such a hard compatibility
> > > breakage just because some people are worried about theoretical evil
> > > maid attacks.
> > > 
> > > HFS/HFS+ mandatory if you want to boot Linux on a classic Mac or PowerMac
> > > and I don't think it's okay to break all these systems running Linux.
> > 
> > If they're so popular, then it should be no trouble to find somebody
> > to volunteer to maintain those filesystems.  Except they've been
> > marked as orphaned since 2011 and effectively were orphaned several
> > years before that (the last contribution I see from Roman Zippel is
> > in 2008, and his last contribution to hfs was in 2006).
> 
> I suspect that this is one of those catch-22 situations: distros are
> going to enable every feature under the sun. That doesn't mean that
> anyone is actually _using_ them these days.
> 
> Is "staging" still a thing? Maybe we should move these drivers into the
> staging directory and pick a release where we'll sunset it, and then see
> who comes out of the woodwork?

No, the train wreck of filesystems in staging proved that it wasn't
a viable process.

We should just follow the same process as we are using for reiser -
mark it as deprecated in place, pick a date that we are going to
remove it, then add a warning (both runtime, in kconfig and probably
in the kernel filesystem documentation) that it is deprecated and
support is going to be removed at a certain date.

We should be applying the same criteria and process for all the
other filesystems that are orphaned, too. We need to much more
proactive about dropping support for unmaintained filesystems that
nobody is ever fixing despite the constant stream of
corruption- and deadlock- related bugs reported against them.

-Dave.
-- 
Dave Chinner
david@fromorbit.com