Re: [PATCH v3] btrfs: free-space-tree: reject mismatched extent and bitmap items

[Qu Wenruo]

在 2026/5/13 00:48, David Sterba 写道:
> On Sun, May 10, 2026 at 11:03:22PM +0800, Zhang Cen wrote:
> > +static int validate_free_space_key(struct btrfs_block_group *block_group,
> > +				   const struct btrfs_key *key,
> > +				   u8 expected_type)
> > +{
> > +	const u64 end = btrfs_block_group_end(block_group);
> > +
> > +	if (unlikely(key->type != expected_type)) {
> > +		btrfs_err(block_group->fs_info,
> > +			  "block group %llu has unexpected free space key type %u, expected %u",
> > +			  block_group->start, key->type, expected_type);
> > +		return -EUCLEAN;
> > +	}
> > +
> > +	if (unlikely(key->objectid + key->offset > end)) {
>
> This has a review comment https://sashiko.dev/#/patchset/20260510152848.3844894-1-rollkingzzc%40gmail.com
> that the expression can overflow. I did a light check if it is valid at
> all (we're still evaluating the quality of AI reviews) but I think in
> this case more checks to the key.offset and key.objectid could be added.
> As this would is in checker it's meant to be extensive so partially
> overlapping conditions are not a problem.
I have already submitted tree-checker enhancement to address this:
https://lore.kernel.org/linux-btrfs/cover.1778460959.git.wqu@xxxxxxxx/T/

Which adds extra overflow and overlap checks for fst.

Thanks,
Qu