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From: "^m'e" <marcoep@gmail.com>
Date: Mon, 29 Jan 2018 14:49:48 +0000
Message-ID: <CAAxOLF9NTd4TcDc1FW23CE=5nR-Kp62=OJz31XmG_LqZBZJmsg@mail.gmail.com>
Subject: Re: btrfs check: backref lost, mismatch with its hash -- can't repair
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: linux-btrfs@vger.kernel.org
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On Mon, Jan 29, 2018 at 2:04 PM, Qu Wenruo <quwenruo.btrfs@gmx.com> wrote:
>
>
> On 2018年01月29日 21:58, ^m'e wrote:
>> Thanks for the advice, Qu!
>>
>> I used the system for a while, did some package upgrades -- writing in
>> the suspect corrupted area. Then tried a btrfs-send to my backup vol,
>> and it failed miserably with a nice kernel oops.
>>
>> So I went for a lowmem repair:
>> ----------------------------------------------------------------------------------------
>> # ./btrfsck.static check --repair --mode=lowmem /dev/sdb3 2>&1 | tee
>> /mnt/custom/rescue/btrfs-recovery/btrfs-repair.BTR-POOL.1.log
>> WARNING: low-memory mode repair support is only partial
>> Fixed 0 roots.
>> checking extents
>> checking free space cache
>> checking fs roots
>> ERROR: failed to add inode 28891726 as orphan item root 257
>> ERROR: root 257 INODE[28891726] is orphan item
>
> At least I need dig the kernel code further to determine if the orphan
> inode handling in btrfs-progs is correct or not.
>
> So there won't be more dirty fix soon.
>
> Hopefully you could get some good backup and restore the system.
>
> At least the problem is limited to a very small range, and it's
> something we could handle easily.
>
> Thanks for all your report,
> Qu
>
>

Right.

Meanwhile, could you please suggest the best course of action? btrfs
rescue or restore?
I have snapshots of my two subvols (rootfs, home -- now fs-checking
them  just in case...)

Cheers,

  Marco