Re: [BUG] kernel BUG at fs/btrfs/scrub.c:1956!, when scrubbing freshly converted ext4

[Yurii Kolesnykov <yurikoles@gmail.com>]

Hi, Zhao Lei

> 
> I reproduced above bug too, with following command:
>   mkfs.ext4 /dev/vdh
>   btrfs-convert /dev/vdh
>   mount /dev/vdh /mnt/tmp1
>   btrfs scrub start -B /dev/vdh
>   (panic)
> 
> The reason is:
> 1: In some case, metadata(leaf) created by btrfs-convert was split into 2 strips.
> 2: Then scrub bypassed part of leaf data, and left data caused panic in
>   scrub_checksum_tree_block().
> 
> For above 1:
> we can get following information after some simple operation.
> a. mkfs.ext4 /dev/vdh
>   btrfs-convert /dev/vdh
> b. btrfs-debug-tree /dev/vdh
>   we can see following item in extent tree:
>   item 25 key (27054080 METADATA_ITEM 0) itemoff 15083 itemsize 33
>   Its logical address is [27054080, 27070464)
>   and acrossed 2 strips:
>   [27000832, 27066368)
>   [27066368, 27131904)
> Qu Wenruo <quwenruo@cn.fujitsu.com> is fixing above problem.
> 
> For above 2:
> scrub is trying to do a "bypass" in this case, but the result is "panic".
> I'll fix it.
> 
> Thanks
> Zhaolei

Could you please share an update on this bug status?
Also, please use bugzilla.