From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 942F8136B for ; Thu, 7 Sep 2023 08:04:08 +0000 (UTC) Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qe9zd-0001DM-Rg; Thu, 07 Sep 2023 10:04:01 +0200 Message-ID: Date: Thu, 7 Sep 2023 10:04:01 +0200 Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [MAINTAINERS/KERNEL SUMMIT] Trust and maintenance of file systems Content-Language: en-US, de-DE To: Matthew Wilcox , Steven Rostedt Cc: Dave Chinner , Guenter Roeck , Christoph Hellwig , ksummit@lists.linux.dev, linux-fsdevel@vger.kernel.org References: <8718a8a3-1e62-0e2b-09d0-7bce3155b045@roeck-us.net> <20230906215327.18a45c89@gandalf.local.home> <20230906225139.6ffe953c@gandalf.local.home> From: Thorsten Leemhuis Autocrypt: addr=linux@leemhuis.info; keydata= xsFNBFJ4AQ0BEADCz16x4kl/YGBegAsYXJMjFRi3QOr2YMmcNuu1fdsi3XnM+xMRaukWby47 JcsZYLDKRHTQ/Lalw9L1HI3NRwK+9ayjg31wFdekgsuPbu4x5RGDIfyNpd378Upa8SUmvHik apCnzsxPTEE4Z2KUxBIwTvg+snEjgZ03EIQEi5cKmnlaUynNqv3xaGstx5jMCEnR2X54rH8j QPvo2l5/79Po58f6DhxV2RrOrOjQIQcPZ6kUqwLi6EQOi92NS9Uy6jbZcrMqPIRqJZ/tTKIR OLWsEjNrc3PMcve+NmORiEgLFclN8kHbPl1tLo4M5jN9xmsa0OZv3M0katqW8kC1hzR7mhz+ Rv4MgnbkPDDO086HjQBlS6Zzo49fQB2JErs5nZ0mwkqlETu6emhxneAMcc67+ZtTeUj54K2y Iu8kk6ghaUAfgMqkdIzeSfhO8eURMhvwzSpsqhUs7pIj4u0TPN8OFAvxE/3adoUwMaB+/plk sNe9RsHHPV+7LGADZ6OzOWWftk34QLTVTcz02bGyxLNIkhY+vIJpZWX9UrfGdHSiyYThHCIy /dLz95b9EG+1tbCIyNynr9TjIOmtLOk7ssB3kL3XQGgmdQ+rJ3zckJUQapLKP2YfBi+8P1iP rKkYtbWk0u/FmCbxcBA31KqXQZoR4cd1PJ1PDCe7/DxeoYMVuwARAQABzSdUaG9yc3RlbiBM ZWVtaHVpcyA8bGludXhAbGVlbWh1aXMuaW5mbz7CwZQEEwEKAD4CGwMFCwkIBwMFFQoJCAsF FgIDAQACHgECF4AWIQSoq8a+lZZX4oPULXVytubvTFg9LQUCX31PIwUJFmtPkwAKCRBytubv TFg9LWsyD/4t3g4i2YVp8RoKAcOut0AZ7/uLSqlm8Jcbb+LeeuzjY9T3mQ4ZX8cybc1jRlsL JMYL8GD3a53/+bXCDdk2HhQKUwBJ9PUDbfWa2E/pnqeJeX6naLn1LtMJ78G9gPeG81dX5Yq+ g/2bLXyWefpejlaefaM0GviCt00kG4R/mJJpHPKIPxPbOPY2REzWPoHXJpi7vTOA2R8HrFg/ QJbnA25W55DzoxlRb/nGZYG4iQ+2Eplkweq3s3tN88MxzNpsxZp475RmzgcmQpUtKND7Pw+8 zTDPmEzkHcUChMEmrhgWc2OCuAu3/ezsw7RnWV0k9Pl5AGROaDqvARUtopQ3yEDAdV6eil2z TvbrokZQca2808v2rYO3TtvtRMtmW/M/yyR233G/JSNos4lODkCwd16GKjERYj+sJsW4/hoZ RQiJQBxjnYr+p26JEvghLE1BMnTK24i88Oo8v+AngR6JBxwH7wFuEIIuLCB9Aagb+TKsf+0c HbQaHZj+wSY5FwgKi6psJxvMxpRpLqPsgl+awFPHARktdPtMzSa+kWMhXC4rJahBC5eEjNmP i23DaFWm8BE9LNjdG8Yl5hl7Zx0mwtnQas7+z6XymGuhNXCOevXVEqm1E42fptYMNiANmrpA OKRF+BHOreakveezlpOz8OtUhsew9b/BsAHXBCEEOuuUg87BTQRSeAENARAAzu/3satWzly6 +Lqi5dTFS9+hKvFMtdRb/vW4o9CQsMqL2BJGoE4uXvy3cancvcyodzTXCUxbesNP779JqeHy s7WkF2mtLVX2lnyXSUBm/ONwasuK7KLz8qusseUssvjJPDdw8mRLAWvjcsYsZ0qgIU6kBbvY ckUWkbJj/0kuQCmmulRMcaQRrRYrk7ZdUOjaYmjKR+UJHljxLgeregyiXulRJxCphP5migoy ioa1eset8iF9fhb+YWY16X1I3TnucVCiXixzxwn3uwiVGg28n+vdfZ5lackCOj6iK4+lfzld z4NfIXK+8/R1wD9yOj1rr3OsjDqOaugoMxgEFOiwhQDiJlRKVaDbfmC1G5N1YfQIn90znEYc M7+Sp8Rc5RUgN5yfuwyicifIJQCtiWgjF8ttcIEuKg0TmGb6HQHAtGaBXKyXGQulD1CmBHIW zg7bGge5R66hdbq1BiMX5Qdk/o3Sr2OLCrxWhqMdreJFLzboEc0S13BCxVglnPqdv5sd7veb 0az5LGS6zyVTdTbuPUu4C1ZbstPbuCBwSwe3ERpvpmdIzHtIK4G9iGIR3Seo0oWOzQvkFn8m 2k6H2/Delz9IcHEefSe5u0GjIA18bZEt7R2k8CMZ84vpyWOchgwXK2DNXAOzq4zwV8W4TiYi FiIVXfSj185vCpuE7j0ugp0AEQEAAcLBfAQYAQoAJgIbDBYhBKirxr6Vllfig9QtdXK25u9M WD0tBQJffU8wBQkWa0+jAAoJEHK25u9MWD0tv+0P/A47x8r+hekpuF2KvPpGi3M6rFpdPfeO RpIGkjQWk5M+oF0YH3vtb0+92J7LKfJwv7GIy2PZO2svVnIeCOvXzEM/7G1n5zmNMYGZkSyf x9dnNCjNl10CmuTYud7zsd3cXDku0T+Ow5Dhnk6l4bbJSYzFEbz3B8zMZGrs9EhqNzTLTZ8S Mznmtkxcbb3f/o5SW9NhH60mQ23bB3bBbX1wUQAmMjaDQ/Nt5oHWHN0/6wLyF4lStBGCKN9a TLp6E3100BuTCUCrQf9F3kB7BC92VHvobqYmvLTCTcbxFS4JNuT+ZyV+xR5JiV+2g2HwhxWW uC88BtriqL4atyvtuybQT+56IiiU2gszQ+oxR/1Aq+VZHdUeC6lijFiQblqV6EjenJu+pR9A 7EElGPPmYdO1WQbBrmuOrFuO6wQrbo0TbUiaxYWyoM9cA7v7eFyaxgwXBSWKbo/bcAAViqLW ysaCIZqWxrlhHWWmJMvowVMkB92uPVkxs5IMhSxHS4c2PfZ6D5kvrs3URvIc6zyOrgIaHNzR 8AF4PXWPAuZu1oaG/XKwzMqN/Y/AoxWrCFZNHE27E1RrMhDgmyzIzWQTffJsVPDMQqDfLBhV ic3b8Yec+Kn+ExIF5IuLfHkUgIUs83kDGGbV+wM8NtlGmCXmatyavUwNCXMsuI24HPl7gV2h n7RI In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-bounce-key: webpack.hosteurope.de;linux@leemhuis.info;1694073848;c480dd8e; X-HE-SMSGID: 1qe9zd-0001DM-Rg [disclaimer: while I agree with many things Christoph, Dave, and Willy said in this thread, I at the same time feel that someone needs to take a stance for our "no regressions rule" here and act as its advocate. I mean, Linus calls it our "#1 rule"; but sure, at the same time it's of course of similar or higher importance that the Kernel does not loose or damage any data users entrusted it, as the Kernel otherwise might be "a pointless piece of code that you might as well throw away"[1].] On 07.09.23 05:26, Matthew Wilcox wrote: > On Wed, Sep 06, 2023 at 10:51:39PM -0400, Steven Rostedt wrote: >> I guess the point I'm making is, what's the burden in keeping it around in >> the read-only state? It shouldn't require any updates for new features, >> which is the complaint I believe Willy was having. > > Old filesystems depend on old core functionality like bufferheads. > > We want to remove bufferheads. > > Who has the responsibility for updating those old filesystmes to use > iomap instead of bufferheads? > > Who has the responsibility for testing those filesystems still work > after the update? > > Who has the responsibility for looking at a syzbot bug report that comes > in twelve months after the conversion is done and deciding whether the > conversion was the problem, or whether it's some other patch that > happened before or after? Isn't the answer to those question the usual one: if you want to change an in-kernel API, you have to switch all in-kernel users (or mark them as broken and remove them later, if they apparently are not used anymore in the wild), and deal with the fallout if a reliable bisection later says that a regression is caused by a chance of yours? The only thing slightly special is the testing story, as those for things like drivers it is a whole lot simpler: developers there can get away with only little or no testing, as the risk of data loss or damage is extremely small. But well, changes to arch/ or mm/ code can lead to data damage or loss on rare or unsupported environments as well. All those CI systems out there that test the kernel in various environments help to catch quite a few of those problems before regular users run into them. So why can't that work similarly for unmaintained file systems? We could even establish the rule that Linus should only apply patches to some parts of the kernel if the test suite for unmaintained file systems succeeded without regressions. And only accept new file system code if a test suite that is easy to integrate in CI systems exists (e.g. something smaller and faster than what the ext4 and xfs developers run regularly, but smaller and faster should likely be good enough here). Ciao, Thorsten [1] that's something Linus once said in the context of a regression, but I think it fits here