Re: GRUB bug with Btrfs multiple devices

[Goffredo Baroncelli <kreijack@inwind.it>]

On 27/11/2019 00.53, Chris Murphy wrote:
> On Tue, Nov 26, 2019 at 2:11 PM Goffredo Baroncelli <kreijack@libero.it> wrote:
>>
>> On 26/11/2019 05.05, Chris Murphy wrote:
>>> grub2-efi-x64-2.02-100.fc31.x86_64
>>> kernel-5.3.13-300.fc31.x86_64
>>>
>>> I've seen this before, so it isn't a regression in either of the above
>>> versions. But I'm also not certain when the regression occurred,
>>> because the last time I tested Btrfs multiple devices (specifically
>>> data single profile), was years ago and I didn't run into this.
>>
>>   From the video, it seems that GRUB complaints about a "failure reading". However GRUB is capable to perform the boot and because the profiles are "single (no redundancy), it seems a "false positive" error.
>>
>> When I added the RADID5/6 support to grub, I remember errors like what you showed. However it happened 1 year ago, so my remember may be wrong.
>> I noticed that GRUB test a lot of disks (hd0 ... hd3) . Could you be so kindly to share the disks layout ? Most error is something like "failure reading sector 0xXX". However I can't read the XX number: could you be so kindly to tell us which number is "XX" ? It seems 0x80... but my eyes are bad and your video is even worse :-)
> 
> It was a dark room and shaky cam was seeking for focus :-D It's 0x80.
> 
> The storage is one CD-ROM drive and one SSD drive. That's it. So I
> don't know why there's hd2 and hd3, it seems like GRUB is confused
> about how many drives there are, but that pre-dates this problem.

If these drives are phantom ones, these could be the root of the problem...

> 
> 
>> I think that the errors is due to the "rescan" logic (see grub commit [1]). Could you try a more recent grub (2.04 instead of 2.02) ?
> 
> Yes Fedora Rawhide has 2.04 in it, so I'll give that a shot next time
> I rebuild this particular laptop, which should be relatively soon; or
> even maybe I can reproduce this problem in a VM with two virtio
> devices.
> 
> 


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