Re: corrupt leaf, unexpected item end, unmountable

[Daniel Dawson <danielcdawson@gmail.com>]

On 2/18/21 9:03 PM, Chris Murphy wrote:
> Once everything else is figured out, you should consider converting
> metadata to raid1c3.

Got it.

> The new replacement is devid 0 during the replacement. The drive being
> replaced keeps its devid until the end, and then there's a switch,
> that device is removed, and the signature on the old drive is wiped.
> Sooo.... something is still wrong with the above because there's no
> devid 3, there's kernel and btrfs check messages saying devid 3 is
> missing.
>
> It doesn't seem likely that /dev/sdc3 is devid 3 because it can't be
> both missing and be the mounted dev node.

It seems I was unclear. I removed the old drive prior to the
replacement, hence degraded mode.

A while ago, I imaged the drives, to see what I could do without risk
(on another machine). Turns out I was able to mount the filesystem using
-o ro,nologreplay,degraded and copy almost all files. A small number
were unreadable/un-stat-able. Fortunately nothing critical, though the
OS may well be unusable.

(Also, in case you were wondering, memory testing has revealed no errors
so far.)

> If a tree log is damaged and prevents mount then, you need to make a
> calculation. You can try to mount with ro,nologreplay and freshen
> backups for anything you'd rather not lose - just in case things get
> worse. And then you can zero the log and see if that'll let you
> normally mount the device (i.e. rw and not degraded). But some of it
> will depend on what's wrong.

That doesn't work. It gives the same errors as when I tried to run
check, but repeated once each for extent tree and device tree. It just
can't get past this problem.

At this point, I think it's best to just reinstall with a fresh
filesystem, and not make the same mistakes. Thanks for the help, once again.