btrfs-convert of ext4 yields unmountable FS

[Paul Collins]

This is with btrfs-progs 5.4.1-2 in focal. Similar result with 5.2.1-1ubuntu1 in eoan.

Following conversion, both mount and btrfs check report an extent that reached beyond the end of the device:

ERROR: dev extent devid 1 physical offset 126701535232 len 33554432 is beyond device boudnary 126726701056

I was doing this booted from a live USB image, so I only have pictures of the screen, which I will attach.

I used -d to speed up creation of the ext2 image, but it also happens without -d.

[Adam Borowski (kilobyte)]

Hi! Could you please send this report to the mailing list (<email address hidden>)? There's too little information for me to even suspect what could be wrong; one of core devs might have an idea outright -- but I guess more info about the image in question will be needed.

[Paul Collins (pjdc)]

Reported upstream: https://bugzilla.kernel.org/show_bug.cgi?id=206995

[Ari Sovijärvi (apz-fi)]

I ran into this today and I see someone actually made a test script to uncover this specific bug:

https://www.spinics.net/lists/linux-btrfs/msg102535.html

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.