Re: [PATCH v2 0/2] btrfs-progs: mkfs free-space-info bug

[Josef Bacik <josef@toxicpanda.com>]

On Mon, Sep 30, 2024 at 03:23:10PM -0700, Leo Martins wrote:
> Currently mkfs creates a few block-groups to bootstrap the filesystem.
> Along with these block-groups some free-space-infos are created. When
> the block-group cleanup happens the block-groups are deleted and the
> free-space-infos are not. This patch set introduces a fix that deletes
> the free-space-infos when the block-groups are deleted.
> 
> When implementing a test for my changes I found that there was already
> some code in free-space-tree.c that attempts to verify that all
> free-space-infos correspond to a block-group. This code only checks if
> there exists a block-group that has an objectid >= free-space-info's
> objectid. I added an additional check to make sure that the block-group
> actually matches the free-space-info's objectid and offset.
> 
> Making this change to fsck will cause all filesystems that were created
> using mkfs.btrfs to warn that there is some free-space-info that doesn't
> correspond to a block-group. This seems like a bad idea, I considered
> adding to the message to signify that this is not a big issue and maybe
> point them to this patchset to get the fix. Open to ideas on how to
> handle this.
> 
> Leo Martins (2):
>   btrfs-progs: delete free space when deleting block group
>   btrfs-progs: check free space maps to block group
> 

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef