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From: Satoru Takeuchi <satoru.takeuchi@gmail.com>
To: Larkin Lowrey <llowrey@nuclearwinter.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Unmountable fs - missing generation?
Date: Thu, 19 Oct 2017 16:58:31 +0900	[thread overview]
Message-ID: <87wp3rzhzs.wl-satoru.takeuchi@gmail.com> (raw)
In-Reply-To: <F2D69F8C-42D0-4AEA-8B24-BB15A10077B5@gmail.com>

At Thu, 19 Oct 2017 12:03:08 +0900,
satoru takeuchi wrote:
> 
> Resend it since I forgot to CC linux-btrfs ML >Larkin
> 
> On Oct 17, 2017, at 0:16, Larkin Lowrey <llowrey@nuclearwinter.com>
> wrote:
> 
>     I am unable to mount one my my filesystems. The superblock thinks
>     the latest generation is 2220927 but I can't seem to find a root
>     with that number. I can find 2220926 and 2220928 but not 2220927.
>     Is there anything that I can do to recover this FS?
>     
> 
> `btrfs-select-super` may help you. Please see the following steps.
> 
> 1. Backup the current unmountable fs image if possible.
> 2. Salvage your files as much as possilbe with reading the following
> document
> if possible.
> 
> https://btrfs.wiki.kernel.org/index.php/Restore
> 
> 3. Execute `btrfs-select-super -s 1 /dev/Cached/Backups`. Please note
> that
> this command changes the contents of /dev/Cached/Backups. So if this
> command fails. Things would get worse.

I forgot to tell one important point. You can only run above mentioned
command iff 1st copy of superblock is valid. It can be confirmed
by `btrfs inspect-internal dump-super (or btrfs-dump-super)` as follows.

* valid case

```
$ sudo btrfs inspect dump-super -a /dev/sdb4
...
superblock: bytenr=67108864, device=/dev/sdb4       # 1st copy of superblock
---------------------------------------------------------
csum			0x423bcd19 [match]
bytenr			67108864
flags			0x1
...
```

* invalid case

```
$ sudo btrfs inspect dump-super -a /dev/sdb4
...
superblock: bytenr=67108864, device=/dev/sdb4
---------------------------------------------------------
ERROR: bad magic on superblock on /dev/sdb4 at 67108864
...
```

Thanks,
Satoru

> Thanks,
> Satoru
> 
>     
>     # btrfs check /dev/Cached/Backups
>     checksum verify failed on 159057884594176 found 15284E33 wanted
>     C8C5B54E
>     checksum verify failed on 159057884594176 found 15284E33 wanted
>     C8C5B54E
>     checksum verify failed on 159057884594176 found 472037C9 wanted
>     9ACDCCB4
>     checksum verify failed on 159057884594176 found 472037C9 wanted
>     9ACDCCB4
>     Csum didn't match
>     Couldn't setup extent tree
>     Couldn't open file system
>     
>     # btrfs-find-root -g 2220927 /dev/Cached/Backups
>     Couldn't setup extent tree
>     Couldn't setup device tree
>     Superblock thinks the generation is 2220927
>     Superblock thinks the level is 2
>     
>     Found tree root at 159057884577792 gen 2220927 level 2
>     Well block 101489031790592(gen: 2220928 level: 2) seems good, but
>     generation/level doesn't match, want gen: 2220927 level: 2
>     
>     # btrfs check --tree-root 159057884577792 /dev/Cached/Backups
>     checksum verify failed on 159057884594176 found 15284E33 wanted
>     C8C5B54E
>     checksum verify failed on 159057884594176 found 15284E33 wanted
>     C8C5B54E
>     checksum verify failed on 159057884594176 found 472037C9 wanted
>     9ACDCCB4
>     checksum verify failed on 159057884594176 found 472037C9 wanted
>     9ACDCCB4
>     Csum didn't match
>     Couldn't setup extent tree
>     Couldn't open file system
>     
>     # btrfs check --tree-root 101489031790592 /dev/Cached/Backups
>     parent transid verify failed on 101489031790592 wanted 2220927
>     found 2220928
>     parent transid verify failed on 101489031790592 wanted 2220927
>     found 2220928
>     parent transid verify failed on 101489031790592 wanted 2220927
>     found 2220928
>     parent transid verify failed on 101489031790592 wanted 2220927
>     found 2220928
>     Ignoring transid failure
>     parent transid verify failed on 159057595138048 wanted 2220927
>     found 2220920
>     parent transid verify failed on 159057595138048 wanted 2220927
>     found 2220920
>     parent transid verify failed on 159057595138048 wanted 2220927
>     found 2220920
>     parent transid verify failed on 159057595138048 wanted 2220927
>     found 2220920
>     Ignoring transid failure
>     parent transid verify failed on 158652658122752 wanted 2220927
>     found 2220911
>     parent transid verify failed on 158652658122752 wanted 2220927
>     found 2220911
>     parent transid verify failed on 158652658122752 wanted 2220927
>     found 2220911
>     parent transid verify failed on 158652658122752 wanted 2220927
>     found 2220911
>     Ignoring transid failure
>     Checking filesystem on /dev/Cached/Backups
>     UUID: 1b213dfd-6486-47d8-8459-bc5825882023
>     checking extents
>     parent transid verify failed on 116329711550464 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329711550464 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329711550464 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329711550464 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116325928206336 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325928206336 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325928206336 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325928206336 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116329892970496 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329892970496 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329892970496 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329892970496 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116325929943040 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325929943040 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325929943040 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325929943040 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116325932679168 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325932679168 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325932679168 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116325932679168 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116010673373184 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116010673373184 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116010673373184 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116010673373184 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116329479405568 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329479405568 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329479405568 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329479405568 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 116480660914176 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116480660914176 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116480660914176 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116480660914176 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     checksum verify failed on 159058014814208 found 406AAC5F wanted
>     C07B44A6
>     checksum verify failed on 159058014814208 found 406AAC5F wanted
>     C07B44A6
>     parent transid verify failed on 159058014814208 wanted 2220927
>     found 2220920
>     checksum verify failed on 159058014814208 found 406AAC5F wanted
>     C07B44A6
>     Csum didn't match
>     parent transid verify failed on 116329821028352 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329821028352 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329821028352 wanted 2220928
>     found 2220921
>     parent transid verify failed on 116329821028352 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     parent transid verify failed on 114958975139840 wanted 2220928
>     found 2220920
>     parent transid verify failed on 114958975139840 wanted 2220928
>     found 2220920
>     parent transid verify failed on 114958975139840 wanted 2220928
>     found 2220920
>     parent transid verify failed on 114958975139840 wanted 2220928
>     found 2220920
>     Ignoring transid failure
>     leaf parent key incorrect 114958975139840
>     bad block 114958975139840
>     Errors found in extent allocation tree or chunk allocation
>     parent transid verify failed on 116329711550464 wanted 2220928
>     found 2220921
>     Ignoring transid failure
>     leaf parent key incorrect 116329711550464
>     
>     
>     --
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>     linux-btrfs" in
>     the body of a message to majordomo@vger.kernel.org
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>     

      parent reply	other threads:[~2017-10-19  7:58 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-16 15:16 Unmountable fs - missing generation? Larkin Lowrey
     [not found] ` <F2D69F8C-42D0-4AEA-8B24-BB15A10077B5@gmail.com>
2017-10-19  7:58   ` Satoru Takeuchi [this message]

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