From: Graham Cobb <g.btrfs@cobb.uk.net>
To: "Sebastian Döring" <moralapostel@gmail.com>, linux-btrfs@vger.kernel.org
Subject: Re: btrfs scrub: cancel + resume not resuming?
Date: Thu, 9 Jan 2020 10:19:24 +0000 [thread overview]
Message-ID: <654bf850-65bf-65f5-2ed2-90a0d4058e74@cobb.uk.net> (raw)
In-Reply-To: <CADkZQakAhrRHFeHPJfne5oLT81qFGbzNAiUoqb3r0cxVSuHTNg@mail.gmail.com>
On 09/01/2020 10:03, Sebastian Döring wrote:
> Maybe I'm doing it entirely wrong, but I can't seem to get 'btrfs
> scrub resume' to work properly. During a running scrub the resume
> information (like data_bytes_scrubbed:1081454592) gets written to a
> file in /var/lib/btrfs, but as soon as the scrub is cancelled all
> relevant fields are zeroed. 'btrfs scrub resume' then seems to
> re-start from the very beginning.
>
> This is on linux-5.5-rc5 and btrfs-progs 5.4, but I've been seeing
> this for a while now.
>
> Is this intended/expected behavior? Am I using the btrfs-progs wrong?
> How can I interrupt and resume a scrub?
Coincidentally, I noticed exactly the same thing yesterday!
I have just run a quick test. It works with kernel 4.19 but doesn't with
kernel 5.3. This is using exactly the same version of btrfs-progs:
v5.3.1 (I just rebooted the same system with an old kernel to check).
As Sebastian says, the symptom is that the file in /var/lib/btrfs shows
all fields as zero after the cancel (although "cancelled" and "finished"
are both 1). In particular, last_physical is zero so the scrub always
resumes from the beginning.
With the old kernel, the file in /var/lib/btrfs correctly has all the
values filled in after the cancel so the scrub can be resumed.
Graham
next prev parent reply other threads:[~2020-01-09 10:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 10:03 btrfs scrub: cancel + resume not resuming? Sebastian Döring
2020-01-09 10:19 ` Graham Cobb [this message]
2020-01-09 17:06 ` Graham Cobb
2020-01-09 20:35 ` Graham Cobb
2020-01-13 13:57 ` btrfs scrub: cancel + resume not resuming - kernel regression Graham Cobb
2020-01-09 10:34 ` btrfs scrub: cancel + resume not resuming? Holger Hoffstätte
2020-01-09 10:52 ` Graham Cobb
2020-01-09 11:05 ` Holger Hoffstätte
2020-01-09 11:13 ` Graham Cobb
2020-01-09 11:16 ` Holger Hoffstätte
2020-01-22 15:52 ` David Sterba
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