On Thu, Aug 31, 2023 at 07:29:53PM +0800, Gao Xiang wrote:
> commit e4c1cf523d820730a86cae2c6d55924833b6f7ac upstream.
>
> This was accidentally fixed up in commit e4c1cf523d82 but we can't
> take the full change due to other dependancy issues, so here is just
> the actual bugfix that is needed.
>
> [Background]
>
> keltargw reported an issue [1] that with mmaped I/Os, sometimes the
> tail of the last page (after file ends) is not filled with zeroes.
>
> The root cause is that such tail page could be wrongly selected for
> inplace I/Os so the zeroed part will then be filled with compressed
> data instead of zeroes.
>
> A simple fix is to avoid doing inplace I/Os for such tail parts,
> actually that was already fixed upstream in commit e4c1cf523d82
> ("erofs: tidy up z_erofs_do_read_page()") by accident.
>
> [1]
> https://lore.kernel.org/r/[email protected]
>
> Reported-by: keltargw <[email protected]>
> Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
> Signed-off-by: Gao Xiang <[email protected]>
> ---
> fs/erofs/zdata.c | 2 ++
> 1 file changed, 2 insertions(+)
All now queued up, thanks.
greg k-h
