Re: [PATCH] erofs-utils: mkfs: also handle last compacted 2B pack in z_erofs_drop_inline_pcluster

Gao Xiang <[email protected]> 于2026年5月11日周一 12:01写道：
>
> Hi Zhiguo,
>
> On 2026/4/29 15:59, Zhiguo Niu wrote:
> > With ztailpacking enabled, the current process assumes that a compacted_4b_end
> > always exists in the compacted pack. However, in some specific files, the
> > compacted pack may not have a compacted_4b_end. This leads to an incorrect
> > modification of the last compacted_2B entry, resulting in incorrect modification
> > of its clusterofs. In subsequent fsck operations, incorrect parameters will
> > affect the decompression of the penultimate pcluster.
> >
> > This patch determines whether the last entry of the current compacted pack
> > belongs to compacted 2B or 4B and then updates the correct bits accordingly.
> >
> > Fixes: a7c1f0575ef8 ("erofs-utils: lib: refine tailpcluster compression approach")
> > Signed-off-by: Zhiguo Niu <[email protected]>
>
> Sorry for late response.
>
> I do think the issue is valid, but either the previous
> solution or the proposed one is ugly.

Hi Xiang,
Yes it would be ideal if the same piece of common code could cover
both scenarios.
But I haven't figured it out yet, so I'll distinguish them like this for now. ^^
thanks!
>
> I wonder if there exists a better way to fixup the last lcluster
> type into plain instead: I've thought about for a while but without
> any valid suggestion.
>
> Thanks,
> Gao Xiang