[arch-general] btrfs kernel incompatibility?

[Simeon Felis]

Am 06.02.20 um 23:03 schrieb Chris Murphy:
> There's not enough information to know what's going on yet. My strong
> advice is to make no further changes (no writes) to either block
> device until you understand exactly what's going on. Every write
> increases the chance of permanently losing the file system.
> 
> 
> On Thu, Feb 6, 2020 at 2:01 PM Simeon Felis <arch-general at sfelis.de> wrote:
>>
>> 4.19.75 dmesg:
>>
>> [   17.707873] GPT:Primary header thinks Alt. header is not at the end of the di
>> sk.
>> [   17.707889] GPT:7814037167 != 253879390758629
>> [   17.707895] GPT:Alternate GPT header not at the end of the disk.
>> [   17.707902] GPT:7814037167 != 253879390758629
>> [   17.707907] GPT: Use GNU Parted to correct GPT errors.
>> [   17.707977]  sdb: sdb1
>> [   17.709682] GPT:Primary header thinks Alt. header is not at the end of the disk.
>> [   17.709697] GPT:7814037167 != 253879390758629
>> [   17.709703] GPT:Alternate GPT header not at the end of the disk.
>> [   17.709710] GPT:7814037167 != 253879390758629
> 
> This is terrible error reporting (by the kernel) in that it's not
> clearly stating whether the primary GPT is reporting 7814037167 or
> 253879390758629. No shit, they aren't the same. Usually this error
> means the backup GPT at the end of the drive has been stepped on by
> something; but LBA 253879390758629 is plainly bogus, that's ~115PiB.
> 
> What do you get for either 'fdisk -l' or 'gdisk -l' or 'parted
> /dev/sda u s p' for each device?

root at omv:~# fdisk -l /dev/sda
Disk /dev/sda: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: USB3.0 DISK03   
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 63E9CA8E-F1B4-8A41-9C21-F058C1AC0783

Device     Start        End    Sectors  Size Type
/dev/sda1   2048 7814037134 7814035087  3.7T Linux filesystem
root at omv:~# fdisk -l /dev/sdb
Disk /dev/sdb: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: USB3.0 DISK04   
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 9904ABA2-B9F8-4544-9699-9935CE8A7B1F

Device     Start        End    Sectors  Size Type
/dev/sdb1   2048 7814035455 7814033408  3.7T Linux filesystem

root at omv:~# gdisk -l /dev/sda
GPT fdisk (gdisk) version 1.0.3

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sda: 7814037168 sectors, 3.6 TiB
Model: USB3.0 DISK03   
Sector size (logical/physical): 512/4096 bytes
Disk identifier (GUID): 63E9CA8E-F1B4-8A41-9C21-F058C1AC0783
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 2048, last usable sector is 7814037134
Partitions will be aligned on 2048-sector boundaries
Total free space is 0 sectors (0 bytes)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048      7814037134   3.6 TiB     8300  
root at omv:~# gdisk -l /dev/sdb
GPT fdisk (gdisk) version 1.0.3

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sdb: 7814037168 sectors, 3.6 TiB
Model: USB3.0 DISK04   
Sector size (logical/physical): 512/4096 bytes
Disk identifier (GUID): 9904ABA2-B9F8-4544-9699-9935CE8A7B1F
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 7814037134
Partitions will be aligned on 2048-sector boundaries
Total free space is 3693 sectors (1.8 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048      7814035455   3.6 TiB     8300