block group xxx has wrong amount of free space

block group xxx has wrong amount of free space

[Михаил Гаврилов]

$ journalctl -b -1 --no-pager | grep BTRFS
May 08 01:28:23 localhost kernel: BTRFS: device fsid
a22dd8bc-24ef-4f97-bb62-01fcd7c3f11c devid 1 transid 25 /dev/sda4
May 08 01:28:23 localhost kernel: BTRFS: device fsid
eaa531cd-25f4-4e00-b31f-22665faa9768 devid 1 transid 333 /dev/sdb
May 08 01:28:23 localhost kernel: BTRFS: device label home devid 1
transid 2326870 /dev/sdc1
May 08 01:28:26 localhost.localdomain kernel: BTRFS info (device
sdc1): disk space caching is enabled
May 08 01:28:26 localhost.localdomain kernel: BTRFS info (device
sdc1): bdev /dev/sdc1 errs: wr 0, rd 14, flush 0, corrupt 0, gen 0
May 08 01:28:39 localhost.localdomain kernel: BTRFS error (device
sdc1): could not find root 8
May 08 01:40:30 localhost.localdomain kernel: BTRFS warning (device
sdc1): block group 2286562574336 has wrong amount of free space
May 08 01:40:30 localhost.localdomain kernel: BTRFS warning (device
sdc1): failed to load free space cache for block group 2286562574336,
rebuilding it now
May 08 02:06:09 localhost.localdomain kernel: BTRFS warning (device
sdc1): block group 3844117364736 has wrong amount of free space
May 08 02:06:09 localhost.localdomain kernel: BTRFS warning (device
sdc1): failed to load free space cache for block group 3844117364736,
rebuilding it now


These messages appear on every boot.
That they means? And how fix it?

$ uname -r
4.5.3-300.fc24.x86_64

--
Best Regards,
Mike Gavrilov.

Re: block group xxx has wrong amount of free space

[Hugo Mills]

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On Sun, May 08, 2016 at 12:10:35PM +0500, Михаил Гаврилов wrote:
> $ journalctl -b -1 --no-pager | grep BTRFS
> May 08 01:28:23 localhost kernel: BTRFS: device fsid
> a22dd8bc-24ef-4f97-bb62-01fcd7c3f11c devid 1 transid 25 /dev/sda4
> May 08 01:28:23 localhost kernel: BTRFS: device fsid
> eaa531cd-25f4-4e00-b31f-22665faa9768 devid 1 transid 333 /dev/sdb
> May 08 01:28:23 localhost kernel: BTRFS: device label home devid 1
> transid 2326870 /dev/sdc1
> May 08 01:28:26 localhost.localdomain kernel: BTRFS info (device
> sdc1): disk space caching is enabled

   All perfectly normal.

> May 08 01:28:26 localhost.localdomain kernel: BTRFS info (device
> sdc1): bdev /dev/sdc1 errs: wr 0, rd 14, flush 0, corrupt 0, gen 0

   As long as the number after "rd" doesn't change, you're OK. This
records all errors that the FS has encountered. You can reset the
values with btrfs dev stat -z.

> May 08 01:28:39 localhost.localdomain kernel: BTRFS error (device
> sdc1): could not find root 8

   This is harmless -- the FS is reporting that something (usually
systemd) was probing to find out if quotas are enabled, and they
aren't.

> May 08 01:40:30 localhost.localdomain kernel: BTRFS warning (device
> sdc1): block group 2286562574336 has wrong amount of free space
> May 08 01:40:30 localhost.localdomain kernel: BTRFS warning (device
> sdc1): failed to load free space cache for block group 2286562574336,
> rebuilding it now
> May 08 02:06:09 localhost.localdomain kernel: BTRFS warning (device
> sdc1): block group 3844117364736 has wrong amount of free space
> May 08 02:06:09 localhost.localdomain kernel: BTRFS warning (device
> sdc1): failed to load free space cache for block group 3844117364736,
> rebuilding it now

   These report that there's a problem with the free space cache. This
is not likely to be damaging, but could impact performance. It will
probably take some time (possibly on the scale of hours, depending on
the size of the FS) for the cache to rebuild, so leave the machine up
for a while. If the cache messages persist, clear it manually by
mounting once with -oclear_cache, then mount again once with
-ospace_cache, and again wait for it to rebuild.

   Hugo.

> These messages appear on every boot.
> That they means? And how fix it?
> 
> $ uname -r
> 4.5.3-300.fc24.x86_64
> 

-- 
Hugo Mills             | Two things came out of Berkeley in the 1960s: LSD
hugo@... carfax.org.uk | and Unix. This is not a coincidence.
http://carfax.org.uk/  |
PGP: E2AB1DE4          |

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