Re: Problem mounting 4-drive RAID1 fs after replace was interrupted by kernel crash

[Qu Wenruo <wqu@suse.com>]

在 2026/4/1 07:53, Jaron Viëtor 写道:
> On Tue, Mar 31, 2026 at 11:14 PM Qu Wenruo <wqu@suse.com> wrote:
[...]
>>
>> Kernel version please.
>>
>> And with all devices (including the new and failing disks), and "btrfs
>> dev scan", the mount still fails with the same message?
>>
>> If so, mount with "degraded" mount option, and try to cancel the
>> replacement, then try again.
> 
> Thanks for your reply!
> This is on kernel 6.19.10, the problem (and start of the replace
> operation) was originally started on kernel 6.18.2 - I updated in
> hopes that would fix things, but it made no difference.
> Yes, with all drives the mount fails with the same message. Attempting
> to mount degraded (or ro,degraded) also gives the exact same message
> as well, so I have no way to cancel the replacement (that I know of).

Then please provide the following dump, just use any device is fine 
(maybe except the replace target/source device):

  # btrfs ins dump-tree -t root <device>

Then the following dump for each device, including the target and source 
device:

  # btrfs ins dump-super -f <device>

I still remember I handled a similar bug before, which seems to be a 
bitflip in the devid.

And just in case, please also run a memtest to rule out any hardware 
memory problems.
You won't believe how frequent such problems are observed, especially if 
your NUC is running DDR4 memory.

Thanks,
Qu

> 
> Kind regards,
> Jaron
> 
>>
>> Thanks,
>> Q