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From: Pierre Abbat <phma@bezitopo.org>
To: linux-btrfs@vger.kernel.org
Subject: Re: Trying to mount hangs
Date: Thu, 21 May 2020 19:48:26 -0400	[thread overview]
Message-ID: <7541432.rVhWMRgfCE@puma> (raw)
In-Reply-To: <87436f2d-40d2-5fa1-cdee-4cc4f63e68c9@gmx.com>

On Thursday, May 21, 2020 3:56:01 AM EDT Qu Wenruo wrote:
> That doesn't sound good. But according to your btrfs check result, your
> memory doesn't look good.
> There seems to be a memory bit flip.
> 
> A full memtest is highly recommended.
> 
> And since your hardware is not functioning reliable, everything can go
> wrong.

There was a thunderstorm. The power blinked twice within a few minutes. That 
could have easily caused the bit flip.

> > UUID: 1f5a6f23-a7ef-46c6-92b1-84fc2f684931
> > [1/7] checking root items
> > [2/7] checking extents
> > incorrect local backref count on 4186230784 root 257 owner 99013 offset
> > 5033684992 found 1 wanted 2097153 back 0x5589817e5ef0
> 
> Here, the 2097153 is 0x200001, it's an obvious bitflip.
> 
> And since it's in extent tree, even write time tree checker can't detect it.
> 
> But that problem is not a big thing, btrfs check --repair can fix it.
> 
> Still, memtest first, only process to try repair after your memory is fixed.

"btrfs check" gave me a "device busy" error. (When I booted the M.2, this was 
caused by the hung mount process, but it happened even when I booted the flash 
drive. I don't know why.) I couldn't repair it. I had to get a new drive and 
recover the files to the new drive.

Trying to mount the corrupt filesystem consistently hangs. That indicates a bug 
in mount. How can I send you the corrupt filesystem so that you can debug 
mount?

Pierre
-- 
The Black Garden on the Mountain is not on the Black Mountain.




  reply	other threads:[~2020-05-21 23:48 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-21  1:34 Trying to mount hangs Pierre Abbat
2020-05-21  7:56 ` Qu Wenruo
2020-05-21 23:48   ` Pierre Abbat [this message]
2020-05-22  1:32     ` Qu Wenruo
2020-05-22  9:40       ` Pierre Abbat
2020-05-22 10:02         ` Qu Wenruo
2020-05-24  6:37           ` Pierre Abbat
2020-05-24  9:24             ` Qu Wenruo
2020-05-24 12:10               ` Pierre Abbat
2020-05-24 12:32                 ` Qu Wenruo
2020-05-27 10:41 ` Qu Wenruo

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