On Mon, 2015-02-09 at 01:18 +0000, Cyril Vechera wrote:
> Package: src:linux
> Version: 3.16.7-ckt4-3
> Severity: important
> File: linux-image-3.16
> Tags: upstream
>
> Dear Maintainer,
>
> For an md mirror with bitmap, when re-adding a device that was
> previously detached during recovery, new recovery starts from the offset
> of last recovery. If there were any writes to the mirror before that
> recovery offset during device was detaching, they will be stored only on
> the present part of mirror and will be ignored on the re-added device.
>
> Bug is detected on following kernels:
> * 3.16 kernel / Debian 8
> * 3.16 kernel / Ubuntu 14.10.
>
> Bug is not detected on following kernels:
> * 3.2 kernel / Debian 7
> * 3.13.0-27-generic kernel / Ubuntu 14.04
> * 3.19.0-rc4 kernel from mainline
Sorry for the delay in replying to this, and thanks very much for the
test script.
I agree with your results for Debian 3.2- and 3.16-based kernel
packages. However I was also able to reproduce this on Debian's version
3.19-1~exp1. I then bisected our package versions and found that his
seems to be a regression between 3.12-1~exp1 and 3.12.3-1~exp1.
I don't know why you couldn't reproduce this on 3.13 or 3.19-rc4.
Anyway, if this was really a regression between 3.12 and 3.12.3 then
this commit is most likely to blame:
commit 52df633c9c9c92264e04e1ead9290e5192a8768e
Author: NeilBrown <neilb@suse.de>
Date: Thu Nov 28 10:34:18 2013 +1100
md: test mddev->flags more safely in md_check_recovery.
commit 142d44c310819e1965ca70b4d55d7679f5797e25 upstream.
However, reverting that didn't fix the bug for me.
Have you reported this upstream yet?
Ben.
--
Ben Hutchings
Absolutum obsoletum. (If it works, it's out of date.) - Stafford Beer
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