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From: Marc Lehmann <schmorp@schmorp.de>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: btrfs dev del not transaction protected?
Date: Fri, 20 Dec 2019 18:20:43 +0100	[thread overview]
Message-ID: <20191220172043.GA5965@schmorp.de> (raw)
In-Reply-To: <204287e5-8aca-3a51-9bc9-be577299bfd6@gmx.com>

> > Just while I was writing this mail, on 5.4.5, the _newly created_ btrfs
> > filesystem I restored to went into readonly mode with ENOSPC. Another
> > hardware problem?
>
> But mounting with clear_cache,space_cache=v2 didn't help, df still shows 0
> bytes free, "btrfs f us" still shows 3tb unallocated. I'll play around with
> it more...

clear_cache didn't work, but btrfsck --clear-space-cache v1 and .. v2 did
work:

   Filesystem               Size  Used Avail Use% Mounted on
   /dev/mapper/xmnt-cold15   27T   23T  3.6T  87% /cold1

Which is rather insane, as I can't see how this filesystem was ever not
mounted without -o space_cache=v2.

Looking at btrfs f u again...

   Metadata,single: Size:1.22GiB, Used:0.00B (0.00%)
      /dev/mapper/xmnt-cold13         1.22GiB

   Metadata,RAID1: Size:27.92GiB, Used:27.90GiB (99.91%)
      /dev/mapper/xmnt-cold15        25.46GiB
      /dev/mapper/xmnt-cold12        24.46GiB
      /dev/mapper/xmnt-cold13         5.92GiB

   System,RAID1: Size:32.00MiB, Used:2.16MiB (6.74%)
      /dev/mapper/xmnt-cold15        32.00MiB
      /dev/mapper/xmnt-cold12        32.00MiB

   Unallocated:
      /dev/mapper/xmnt-cold15         1.00MiB
      /dev/mapper/xmnt-cold12         1.00MiB
      /dev/mapper/xmnt-cold13         3.24TiB

Did this happen because metadata is raid1 and two of the disks were full,
and for some reason, btrfsck freed up a tiny bit of space somewhere?

-- 
                The choice of a       Deliantra, the free code+content MORPG
      -----==-     _GNU_              http://www.deliantra.net
      ----==-- _       generation
      ---==---(_)__  __ ____  __      Marc Lehmann
      --==---/ / _ \/ // /\ \/ /      schmorp@schmorp.de
      -=====/_/_//_/\_,_/ /_/\_\

      parent reply	other threads:[~2019-12-20 17:20 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-20  4:05 btrfs dev del not transaction protected? Marc Lehmann
2019-12-20  5:24 ` Qu Wenruo
2019-12-20  6:37   ` Marc Lehmann
2019-12-20  7:10     ` Qu Wenruo
2019-12-20 13:27       ` Marc Lehmann
2019-12-20 13:41         ` Qu Wenruo
2019-12-20 16:53           ` Marc Lehmann
2019-12-20 17:24             ` Remi Gauvin
2019-12-20 17:50               ` Marc Lehmann
2019-12-20 18:00               ` Marc Lehmann
2019-12-20 18:28                 ` Eli V
2019-12-20 20:24             ` Chris Murphy
2019-12-20 23:30               ` Marc Lehmann
2019-12-21 20:06               ` Zygo Blaxell
2019-12-21  1:32             ` Qu Wenruo
2019-12-20 17:07           ` Marc Lehmann
2019-12-21  1:23             ` Qu Wenruo
2019-12-20 17:20           ` Marc Lehmann [this message]

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