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

Message

Leo Martins Sept. 30, 2024, 10:23 p.m. UTC

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

 common/clear-cache.c            |  3 ++-
 kernel-shared/extent-tree.c     | 10 ++++++++++
 kernel-shared/free-space-tree.c |  3 +++
 3 files changed, 15 insertions(+), 1 deletion(-)