From: David Sterba <dsterba@suse.cz>
To: Chris Murphy <lists@colorremedies.com>
Cc: Martin Steigerwald <martin@lichtvoll.de>,
Martin Raiber <martin@urbackup.org>,
Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: With Linux 5.5: Filesystem full while still 90 GiB free
Date: Thu, 30 Jan 2020 18:19:50 +0100 [thread overview]
Message-ID: <20200130171950.GZ3929@twin.jikos.cz> (raw)
In-Reply-To: <CAJCQCtSVqMBONCuwea_9i6xBkzOHSkCSoEAaDi2aH+-CLnNwBg@mail.gmail.com>
On Wed, Jan 29, 2020 at 03:55:06PM -0700, Chris Murphy wrote:
> On Wed, Jan 29, 2020 at 2:20 PM Martin Steigerwald <martin@lichtvoll.de> wrote:
> >
> > So if its just a cosmetic issue then I can wait for the patch to land in
> > linux-stable. Or does it still need testing?
>
> I'm not seeing it in linux-next. A reasonable short term work around
> is mount option 'metadata_ratio=1' and that's what needs more testing,
> because it seems decently likely mortal users will need an easy work
> around until a fix gets backported to stable. And that's gonna be a
> while, me thinks.
We're looking into some fix that could be backported, as it affects a
long-term kernel (5.4).
The fix
https://lore.kernel.org/linux-btrfs/20200115034128.32889-1-wqu@suse.com/
IMHO works by accident and is not good even as a workaround, only papers
over the problem in some cases. The size of metadata over-reservation
(caused by a change in the logic that estimates the 'over-' part) adds
up to the global block reserve (that's permanent and as last resort
reserve for deletion).
In other words "we're making this larger by number A, so let's subtract
some number B". The fix is to use A.
> Is that mount option sufficient? Or does it take a filtered balance?
> What's the most minimal balance needed? I'm hoping -dlimit=1
>
> I can't figure out a way to trigger this though, otherwise I'd be
> doing more testing.
I haven't checked but I think the suggested workarounds affect statfs as
a side effect. Also as the reservations are temporary, the numbers
change again after a sync.
next prev parent reply other threads:[~2020-01-30 17:20 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 19:33 With Linux 5.5: Filesystem full while still 90 GiB free Martin Steigerwald
2020-01-29 20:04 ` Martin Raiber
2020-01-29 21:20 ` Martin Steigerwald
2020-01-29 22:55 ` Chris Murphy
2020-01-30 10:41 ` Martin Steigerwald
2020-01-30 16:37 ` Chris Murphy
2020-01-30 20:02 ` Martin Steigerwald
2020-01-30 20:18 ` Chris Murphy
2020-01-30 20:59 ` Josef Bacik
2020-01-30 21:09 ` Chris Murphy
2020-01-30 21:32 ` Martin Raiber
2020-01-30 21:42 ` Josef Bacik
2020-01-30 21:12 ` Martin Steigerwald
2020-01-30 21:10 ` Martin Steigerwald
2020-01-30 21:20 ` Remi Gauvin
2020-01-30 23:12 ` Martin Steigerwald
2020-01-31 1:43 ` Matt Corallo
2020-01-31 1:57 ` Qu Wenruo
2020-03-02 1:57 ` Etienne Champetier
2020-03-02 1:59 ` Qu Wenruo
2020-01-31 4:12 ` Etienne Champetier
2020-01-30 17:19 ` David Sterba [this message]
2020-01-30 19:31 ` Chris Murphy
2020-01-30 19:58 ` Martin Steigerwald
2020-01-31 3:00 ` Zygo Blaxell
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