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From: Chris Murphy <lists@colorremedies.com>
To: Lee Fleming <leeflemingster@gmail.com>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: Unbootable root btrfs
Date: Thu, 16 May 2019 15:39:08 -0600	[thread overview]
Message-ID: <CAJCQCtTmZY-UHeNYp=waTV8TWiAKXr8bJq13DQ7KQg=syvQ=tg@mail.gmail.com> (raw)
In-Reply-To: <CAKS=YrP=z2+rP5AtFKkf7epi+Dr2Arfsaq3pZ9cR3iKif3gV5g@mail.gmail.com>

On Thu, May 16, 2019 at 4:37 AM Lee Fleming <leeflemingster@gmail.com> 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

  reply	other threads:[~2019-05-16 21:39 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-16 10:36 Unbootable root btrfs Lee Fleming
2019-05-16 21:39 ` Chris Murphy [this message]
     [not found]   ` <CAKS=YrMB6SNbCnJsU=rD5gC6cR5yEnSzPDax5eP-VQ-UpzHvAg@mail.gmail.com>
2019-05-18  4:06     ` Chris Murphy
2019-05-18  4:39       ` Robert White
2019-05-18 19:28         ` Chris Murphy
2019-05-18 19:43           ` Lee Fleming

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