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[209.85.219.172]) by smtp.gmail.com with ESMTPSA id h6-20020a0df706000000b0058c55d40765sm1496260ywf.106.2023.09.10.10.26.42 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 10 Sep 2023 10:26:42 -0700 (PDT) Received: by mail-yb1-f172.google.com with SMTP id 3f1490d57ef6-d7eed15ad69so3471086276.1 for ; Sun, 10 Sep 2023 10:26:42 -0700 (PDT) X-Received: by 2002:a25:2488:0:b0:d74:6c9f:e734 with SMTP id k130-20020a252488000000b00d746c9fe734mr7321441ybk.47.1694366801859; Sun, 10 Sep 2023 10:26:41 -0700 (PDT) MIME-Version: 1.0 References: <8dd2f626f16b0fc863d6a71561196950da7e893f.camel@HansenPartnership.com> <20230909224230.3hm4rqln33qspmma@moria.home.lan> <20230910163533.ysbcztauujywrbk4@moria.home.lan> In-Reply-To: <20230910163533.ysbcztauujywrbk4@moria.home.lan> From: Geert Uytterhoeven Date: Sun, 10 Sep 2023 19:26:26 +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: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, Sep 10, 2023 at 6:35 PM Kent Overstreet wrote: > On Sun, Sep 10, 2023 at 10:19:30AM +0200, Geert Uytterhoeven wrote: > > On Sun, Sep 10, 2023 at 12:42 AM 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 idea), > > 2. Once a file system is removed from the kernel, would the user space > > implementation be maintained better? > > This would be for the filesystems that aren't getting maintained and > tested, to eliminate accidental breakage from in-kernel refactoring and > changing of APIs. > > Getting that code out of the kernel would also greatly help with > security concerns. OK, xkcd 1200 it is... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds