Re: [PATCH 01/19] btrfs: require at least 4 devices for RAID 6
Qu Wenruo <[email protected]>
| Newsgroups | gmane.linux.kernel.cross-arch,gmane.linux.kernel,gmane.linux.ports.arm.kernel,gmane.linux.ports.ppc64.devel,gmane.linux.ports.riscv,gmane.linux.kernel.cryptoapi,gmane.comp.file-systems.btrfs,gmane.linux.raid |
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| Message-ID | <[email protected]> |
在 2026/5/22 09:47, Andrew Morton 写道: > On Wed, 20 May 2026 18:11:09 +0930 Qu Wenruo <[email protected]> wrote: > >> >> >> 在 2026/5/18 14:42, Christoph Hellwig 写道: >>> On Fri, May 15, 2026 at 12:59:34PM -0700, H. Peter Anvin wrote: >>>> I don't think this is a good idea. Error out; it is the btrfs maintainers' job to ensure user data isn't lost. >>>> >>>> The RAID-6 code has *never* supported only 3 units, and if it ever worked for *any* of the implementations it was purely by accident. Speaking as the original author I should know; this was deliberate as in some cases the degenerate case (3) would have required extra trays in the code to no user benefit. >>>> >>>> I would not be surprised if the kernel crashed or corrupted the page cache in that case. >>> >>> It does, that's why I wanted to exclude it. Anyway, for the about to be >>> resent version I'll drop this btrfs patch over the stated objection and >>> will otherwise not change anything. This means the (IMHO hypothetical) >>> users of this configuration will get a WARN_ON_ONCE triggered, but >>> otherwise keep working (or rather not working) as before. >>> >> >> For the btrfs part, I believe I can get the current 2-disk-raid5 and >> 3-disk-raid6 to fallback to raid1 inside btrfs. >> >> I hope the btrfs part can be finished and reach the next merge window, >> but I'm not 100% sure. >> >> What is the planned cycle to merge this raid5/6 cleanup? > > At present it's on track for the 7.2-rc1 merge window. Does that suit? The current btrfs fix (*) is pretty small, I believe we can get it into the next merge window, as long as we got enough review on it. *: https://lore.kernel.org/linux-btrfs/a1d63733465229936351804f3760803d5894a962.1779274630.git.wqu@suse.com/T/#u