From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f182.google.com (mail-yw1-f182.google.com [209.85.128.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 196941FBC for ; Sun, 10 Sep 2023 08:19:47 +0000 (UTC) Received: by mail-yw1-f182.google.com with SMTP id 00721157ae682-5922b96c5fcso32115317b3.0 for ; Sun, 10 Sep 2023 01:19:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694333987; x=1694938787; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TQDVEYR0NkrDO5D5DNG/VELdAd044MCaEh/R0RnIJkc=; b=TWt4IhvX2EQx096jFTnPLigElj46WGcoqHGaRbMQzy+/ZTRoH/x3LSn6zxEXONP6it 8hS9PoLAgGxgpEtz5YUTuGxiCXCYfDRdT2OfzuJOmATsOZChC6B3RqH/LEbIteGL3IxT IneccxtGz5TTYmv8EiOW8dYUyo5EIBUOSWIv89/G/Y7kQmSg+Yxe10ti4YsR4dKcKrz5 z5+0K73y+oESYJoKyipM7h0RicZRraR+Dvmp2izdAhcCO456aYSkEDr2V3m/xXEdg31Y KQteGCaMuMoGyZD7mVBxPh0QOSH87K4NUliieZCvv0hUoP9NHv2CCJntPplhiBmeB1dP 66MA== X-Gm-Message-State: AOJu0YxqaFOGKGIAt/kbJzqgRkR+Ue03a7EWxFNS10UG4vWuGL4vVbb8 dOX6i2PfwfWFB/WmhlSTByw9wWxfuJQVRg== X-Google-Smtp-Source: AGHT+IHxMfSmo7z1AoqMQWHfWQyHjTPMiowLMYsh3+NalLwc6KKDX1rLL+YPPyemLGNoRi9IRhhJ2g== X-Received: by 2002:a81:4987:0:b0:592:9433:d2f5 with SMTP id w129-20020a814987000000b005929433d2f5mr6772911ywa.5.1694333986746; Sun, 10 Sep 2023 01:19:46 -0700 (PDT) Received: from mail-yb1-f170.google.com (mail-yb1-f170.google.com. [209.85.219.170]) by smtp.gmail.com with ESMTPSA id o186-20020a0de5c3000000b0055a07e36659sm1311138ywe.145.2023.09.10.01.19.45 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 10 Sep 2023 01:19:45 -0700 (PDT) Received: by mail-yb1-f170.google.com with SMTP id 3f1490d57ef6-d7eccc1b8c6so3257545276.0 for ; Sun, 10 Sep 2023 01:19:45 -0700 (PDT) X-Received: by 2002:a25:ab8d:0:b0:d53:f98f:8018 with SMTP id v13-20020a25ab8d000000b00d53f98f8018mr6592647ybi.65.1694333985224; Sun, 10 Sep 2023 01:19:45 -0700 (PDT) Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <8dd2f626f16b0fc863d6a71561196950da7e893f.camel@HansenPartnership.com> <20230909224230.3hm4rqln33qspmma@moria.home.lan> In-Reply-To: <20230909224230.3hm4rqln33qspmma@moria.home.lan> From: Geert Uytterhoeven Date: Sun, 10 Sep 2023 10:19:30 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [MAINTAINERS/KERNEL SUMMIT] Trust and maintenance of file systems To: Kent Overstreet Cc: James Bottomley , Matthew Wilcox , Dave Chinner , Christoph Hellwig , ksummit@lists.linux.dev, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Kent, On Sun, Sep 10, 2023 at 12:42=E2=80=AFAM Kent Overstreet wrote: > On Sat, Sep 09, 2023 at 08:50:39AM -0400, James Bottomley wrote: > > So why can't we figure out that easier way? What's wrong with trying to > > figure out if we can do some sort of helper or library set that assists > > supporting and porting older filesystems. If we can do that it will not > > only make the job of an old fs maintainer a lot easier, but it might > > just provide the stepping stones we need to encourage more people climb > > up into the modern VFS world. > > What if we could run our existing filesystem code in userspace? > > bcachefs has a shim layer (like xfs, but more extensive) to run nearly > the entire filesystem - about 90% by loc - in userspace. > > Right now this is used for e.g. userspace fsck, but one of my goals is > to have the entire filesystem available as a FUSE filesystem. I'd been > planning on doing the fuse port as a straight fuse implementation, but > OTOH if we attempted a sh vfs iops/aops/etc. -> fuse shim, then we would > have pretty much everything we need to run any existing fs (e.g. > reiserfs) as a fuse filesystem. > > It'd be a nontrivial project with some open questions (e.g. do we have > to lift all of bufferheads to userspace?) but it seems worth > investigating. 1. https://xkcd.com/1200/ (not an exact match, but you should get the ide= a), 2. Once a file system is removed from the kernel, would the user space implementation be maintained better? Gr{oetje,eeting}s, Geert --=20 Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k= .org In personal conversations with technical people, I call myself a hacker. Bu= t when I'm talking to journalists I just say "programmer" or something like t= hat. -- Linus Torvalds