gazillions of Incorrect local/global backref count

[Christoph Anton Mitterer <calestyo@scientia.net>]

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Hey.

I just did a btrfs check on my notebooks root fs, with:
$ uname -a
Linux heisenberg 4.7.0-1-amd64 #1 SMP Debian 4.7.2-1 (2016-08-28)
x86_64 GNU/Linux
$ btrfs --version
btrfs-progs v4.7.1



during:
checking extents

it found gazillions of these:
Incorrect local backref count on 1107980288 root 257 owner 17807428
offset 13568135168 found 2 wanted 3 back 0x2d69990
Incorrect local backref count on 1107980288 root 257 owner 14055042
offset 13568135168 found 2 wanted 3 back 0x2d69930
Incorrect global backref count on 1107980288 found 4 wanted 6
backpointer mismatch on [1107980288 61440]
Incorrect local backref count on 1108049920 root 257 owner 17807428
offset 13568262144 found 2 wanted 5 back 0x2d69ac0
Incorrect local backref count on 1108049920 root 257 owner 14055042
offset 13568262144 found 2 wanted 5 back 0x2d69b20
Incorrect global backref count on 1108049920 found 4 wanted 10
backpointer mismatch on [1108049920 77824]

See stdout/err[0] logfiles from the check.


What do they mean?

And does this now mean that data is corrupted and I should try to
recover that from a backup?
And if so... how to I map the affected addresses above back to files?

Or can I somehow simply (and foremost cleanly/perfectly) correct these
errors?


Thanks in advance,
Chris.


[0] http://christoph.anton.mitterer.name/tmp/public/dbf3aee0-725a-11e6-8fd0-0019dbacbbbf/

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