Re: [PATCH v6 18/31] ext4: drain writeback before removing extents on the iomap path

[sashiko-bot@kernel.org]

> From: Zhang Yi <yi.zhang@huawei.com>
> 
> Because the iomap infrastructure does not always create an ifs to
> manage sub-folio state when folio size is larger than blocksize,
> invalidating a partial dirty folio during punch hole may fail to
> clear the dirty state of the affected range. As a result, writeback
> of that folio may observe a hole. At writeback submit time,
> ext4_map_blocks() already handles this case and will not allocate
> blocks. However, when punch hole races with writeback, the
> following scenario can cause I/O completion to encounter a hole.
> 
>   punch hole                        writeback
>   ----------                        ---------
>   ext4_punch_hole()
>     ext4_truncate_page_cache_block_range()
> [ ... ]
> always maintain an ifs when folio size is larger than blocksize, so that
> partial invalidate reliably clears sub-block dirty bits and no draining
> is needed.
> 
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260903123543.2302999-1-yi.zhang@huaweicloud.com?part=18