From: Marc MERLIN <marc@merlins.org>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: btrfs check --repair: ERROR: cannot read chunk root
Date: Sun, 30 Oct 2016 22:47:19 -0700 [thread overview]
Message-ID: <20161031054719.GN28648@merlins.org> (raw)
In-Reply-To: <60a0ce1f-7b2f-325e-51f7-ccad054fab8b@cn.fujitsu.com>
On Mon, Oct 31, 2016 at 01:27:56PM +0800, Qu Wenruo wrote:
> Would you please dump the following bytes?
> That's the chunk root tree block on your disk.
>
> offset: 13500329066496 length: 16384
> offset: 13500330213376 length: 16384
Sorry for asking, am I doing this wrong?
myth:~# dd if=/dev/mapper/crypt_bcache0 of=/tmp/dump1 bs=512 count=32
skip=26367830208
dd: reading `/dev/mapper/crypt_bcache0': Invalid argument
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000401393 s, 0.0 kB/s
> According to your fsck error output, I assume btrfs-progs fails to read
> the first copy of chunk root, and due to a bug, it doesn't continue to
> read 2nd copy.
>
> While kernel continues to read the 2nd copy and everything goes on.
Ah, that would make sense.
But from what you're saying, I should be able to do recovery by pointing
to the 2nd copy of the chunk root, but somehow I haven't typed the right
command to do so yet, correct?
Should I try another command offset than
btrfs check -p --repair --chunk-root 13835462344704 /dev/mapper/crypt_bcache0
?
Or are you saying the btrfs progs bug causes it to fail to even try to read
the 2nd copy of the chunk root even though it was given on the command line?
Thanks,
Marc
--
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
.... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/
next prev parent reply other threads:[~2016-10-31 5:47 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-30 18:34 btrfs check --repair: ERROR: cannot read chunk root Marc MERLIN
2016-10-31 1:02 ` Qu Wenruo
2016-10-31 2:06 ` Marc MERLIN
2016-10-31 4:21 ` Marc MERLIN
2016-10-31 5:27 ` Qu Wenruo
2016-10-31 5:47 ` Marc MERLIN [this message]
2016-10-31 6:04 ` Qu Wenruo
2016-10-31 6:25 ` Marc MERLIN
2016-10-31 6:32 ` Qu Wenruo
2016-10-31 6:37 ` Marc MERLIN
2016-10-31 7:04 ` Qu Wenruo
2016-10-31 8:44 ` Hugo Mills
2016-10-31 15:04 ` Marc MERLIN
2016-11-01 3:48 ` Marc MERLIN
2016-11-01 4:13 ` Qu Wenruo
2016-11-01 4:21 ` Marc MERLIN
2016-11-04 8:01 ` Marc MERLIN
2016-11-04 9:00 ` Roman Mamedov
2016-11-04 17:59 ` Marc MERLIN
2016-11-07 1:11 ` Qu Wenruo
[not found] ` <87lgwwnnyf.fsf@notabene.neil.brown.name>
2016-11-07 1:20 ` clearing blocks wrongfully marked as bad if --update=no-bbl can't be used? Marc MERLIN
2016-11-07 1:39 ` Qu Wenruo
2016-11-07 4:18 ` Qu Wenruo
2016-11-07 5:36 ` btrfs support for filesystems >8TB on 32bit architectures Marc MERLIN
2016-11-07 6:16 ` Qu Wenruo
2016-11-07 14:55 ` Marc MERLIN
2016-11-08 0:35 ` Qu Wenruo
2016-11-08 0:39 ` Marc MERLIN
2016-11-08 0:43 ` Qu Wenruo
2016-11-08 1:06 ` Marc MERLIN
2016-11-08 1:17 ` Qu Wenruo
2016-11-08 15:24 ` Marc MERLIN
2016-11-09 1:50 ` Qu Wenruo
2016-11-09 2:05 ` Marc MERLIN
2016-11-11 3:48 ` Marc MERLIN
2016-11-11 3:55 ` Qu Wenruo
2016-11-12 3:17 ` when btrfs scrub reports errors and btrfs check --repair does not Marc MERLIN
2016-11-13 15:06 ` Marc MERLIN
2016-11-13 15:13 ` Roman Mamedov
2016-11-13 15:52 ` Marc MERLIN
-- strict thread matches above, loose matches on Subject: below --
2016-10-31 1:29 btrfs check --repair: ERROR: cannot read chunk root Janos Toth F.
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