Re: [PATCH 11/13] ext4: allow encryption with a block size larger than the page size

[sashiko-bot@kernel.org]

> ext4 refuses encryption when the block size is larger than the page
> size, both at mount time and on a mounted filesystem, and refuses to
> load an existing encrypted inode.  The checks exist because such a
> block size needs folios that cover a whole block, while file contents
> were encrypted page by page in the fs-layer path, which cannot handle a
> folio that covers several data units.
> 
> Since commit 5acc6f649a68 ("fscrypt: Always use blk-crypto for contents
> on block-based filesystems") file contents are always encrypted through
> blk-crypto, and after the adaptations in the preceding patches, both
> inline encryption hardware and blk-crypto-fallback support data units
> larger than a page, so the checks can be removed.
> 
> Encrypted filesystems still keep their folio order at s_min_folio_order;
> allowing large folios needs additional work and will be enabled later.
> 
> Performance:
> 
> Hardware: 96-core machine, 3.84T NVMe, 512G memory
> Filesystem: ext4, encryption on the fallback path
> 
> Buffered sequential 1M writes and reads (1G, fsync) in MiB/s; medians
> of 3 runs.
> 
>   job          4k plain      4k enc    32k plain    32k enc    4k->32k
>   ---------    --------    --------    ---------    -------    -------
>   seqwrite         1981        1044         2062       1399       +34%
>   seqread          1139         931         1791       1793       +93%
> 
> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261011170958.1759230-1-libaokun@linux.alibaba.com?part=11