Re: Massive filesystem corruption since kernel 5.2 (ARCH)

["Swâmi Petaramesh" <swami@petaramesh.org>]

Hi Qu,

Le 27/08/2019 à 08:21, Qu Wenruo a écrit :
> If free space cache is invalid but passes its csum check, it's
> completely *possible* to break metadata CoW, thus leads to transid mismatch.
> 
> You can go v2 space cache which uses metadata CoW to protect its space
> cache, thus in theory it should be a little safer than V1 space cache.
> 
> Or you can just disable space cache using nospace_cache mount option, as
> it's just an optimization. It's also recommended to clean existing cache
> by using "btrfs check --clear-space-cache v1".
> 
> I'd prefer to do a "btrfs check --readonly" anyway (which also checks
> free space cache), then go nospace_cache if you're concerned.

I will leave for travel shortly, so I will be unable to perform further
tests on this machine for a week, but I'll do when I'm back.

Should I understand your statement as an advice to clear the space cache
even though the kernel said it has rebuilt it, or to use the V2 space
cache generally speaking, on any machine that I use (I had understood it
was useful only on multi-TB filesystems...)

Thanks.

ॐ

-- 
Swâmi Petaramesh <swami@petaramesh.org> PGP 9076E32E