On Thu, May 16, 2019 at 4:37 AM Lee Fleming <leeflemingster@xxxxxxxxx> wrote:
> And a btrfs check gives the following:
>
> % btrfs check --repair /dev/mapper/vg-root
Why use repair? From the man page
Warning
Do not use --repair unless you are advised to do so by a developer
or an experienced user
> [ 17.429845] BTRFS error (device dm-1): failed to read block groups: -5
> [ 17.450035] BTRFS error (device dm-1): open_ctree failed
Was there a crash or powerfailure during write before the problem
started? What precipitated the problem?
It might be possible to successfully mount with '-o ro,nologreplay,degraded'
If that works, I'd take the opportunity to refresh backups. I'm not
sure if this can be repaired but also not sure what the problem is.
If it doesn't work, then the next step until a developer has an
opinion on it, is 'btrfs restore' which is a way to scrape data out of
an unmountable file system. It's better than nothing if the data is
important, but ideal if at least ro mount can work.
--
Chris Murphy
