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From: Sebastian Ochmann <ochmann@informatik.uni-bonn.de>
To: 1i5t5.duncan@cox.net
Cc: linux-btrfs@vger.kernel.org
Subject: Re: 2 errors when scrubbing - but I don't know what they mean
Date: Sat, 30 Nov 2013 12:31:33 +0100	[thread overview]
Message-ID: <5299CC95.6010704@informatik.uni-bonn.de> (raw)
In-Reply-To: <pan$e58f7$107ceb0e$e753a400$c76bf1d5@cox.net>

Hello,

thank you for your input. I didn't know that btrfs keeps the error 
counters over mounts/reboots, but that's nice.

I'm still trying to figure out how such a generation error may occur in 
the first place. One thing I noticed looking at the btrfs code is that 
the generation error counter will only get incremented in the actual 
scrubbing code (either in "scrub_checksum_super" or in 
"scrub_handle_errored_block", both in scrub.c - please correct me if I'm 
wrong, I'm not a btrfs dev). Also, the dmesg errors I saw were not there 
at boot time, but about 10 minutes after boot which was about the time 
when I started the scrub so I'm pretty sure that it was the scrub that 
detected the errors.

The question remains what can cause superblock/gen errors. Sure it could 
be "some" read error, but I'd really like to make sure that it's not a 
systematic error. I wasn't able to reproduce it yet though.

Best
Sebastian

  reply	other threads:[~2013-11-30 11:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-28 20:36 2 errors when scrubbing - but I don't know what they mean Sebastian Ochmann
2013-11-29  1:10 ` Duncan
2013-11-30 11:31   ` Sebastian Ochmann [this message]
     [not found]     ` <CAP9B-Q=Y+uY2kErYb1ZKMsvFrbYidmGpPnUbHm8iApj7v6wK+w@mail.gmail.com>
2013-12-01  1:16       ` Fwd: " Shilong Wang
2013-12-01 20:45       ` Sebastian Ochmann
2013-12-02  1:30         ` Wang Shilong
2013-12-02  1:53           ` Wang Shilong
2013-12-02  9:21         ` Wang Shilong
2013-11-29  5:51 ` Wang Shilong

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