From: Chris Murphy <lists@colorremedies.com>
To: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: bug: btrfs device stats not showing raid1 errors
Date: Mon, 20 Sep 2021 10:37:10 -0600 [thread overview]
Message-ID: <CAJCQCtRbktnZ5NxRTZL9UKvTr1TaFtkCbeCS2pVnf2SPg8O3-w@mail.gmail.com> (raw)
https://bugzilla.redhat.com/show_bug.cgi?id=2005987
Various kernel messages like this:
[2634355.709564] BTRFS info (device sda3): read error corrected: ino
27902168 off 8773632 (dev /dev/sda3 sector 52960104)
[2634355.733898] BTRFS info (device sda3): read error corrected: ino
27902168 off 8749056 (dev /dev/sda3 sector 52960056)
And yet 'btrfs dev stats' does not show an increment in tracked
statistics, in particular read_io_errs
This does seem like suboptimal behavior. Discussed a bit on IRC today
and Zygo found the behavior is introduced with commit 0cc068e6ee59
btrfs: don't report readahead errors and don't update statistics
Zygo on IRC writes:
readahead errors are things like "out of memory" or device-mapper nonsense
so the best is 'don't correct and don't count'
since there's probably nothing wrong with the underlying media
but if there is something wrong with the underlying media, we want a
proper read, correct, and count to happen
which means we can safely do nothing during readahead
so the right answer is don't correct and don't count
---
I'm not sure how noisy it could be to always report such read errors
discovered during read ahead, but my gut instinct is that anytime
there's a read error whether physical or virtual, we probably want to
know about this? If these are bogus errors then that suggests (a) do
not increment the dev stats counter, and also (b) do not fix up.
--
Chris Murphy
next reply other threads:[~2021-09-20 16:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 16:37 Chris Murphy [this message]
2021-09-20 19:42 ` bug: btrfs device stats not showing raid1 errors waxhead
2021-09-21 19:57 ` Chris Murphy
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