Wednesday 14 March 2018

Re: ext4 metadata_csum and backwards compatibility

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On 2018-03-14 07:17 AM, Robie Basak wrote:
> 3) We backport metadata_csum support to Xenial in an SRU[1] without
> changing the default there. Xenial users will be able to fsck
> Bionic-created ext4 filesystems. There will be forward compatibilty
> problems when skipping across multiple LTSs (eg. Trusty accessing a
> Bionic-created ext4 filesystem), but not across any single LTS.

I'd vote for this ^, SRU to Xenial. When a new LTS arrives, I typically
test it extensively in VMs running off of an hypervisor running the
previous LTS. Being able to fsck the VM's filesystem is sometimes
convenient. Also, since the metadata checksum was enabled in 16.10+ I'd
rather not go back in terms of default enabled features, especially if
this one is now production ready.

Regards,
Simon