Re: [PATCH 08/13] block: split encrypted bios at data unit boundaries

[sashiko-bot@kernel.org]

> Splitting a bio advances the remaining bio's data unit number by the
> number of whole data units that were split off:
> 
>   bio_split()
>    └─ bio_advance()
>       └─ bio_crypt_advance()
>          └─ bio_crypt_dun_increment(dun, bytes >> data_unit_size_bits)
> 
> The shift truncates, so splitting inside a data unit leaves the
> remainder with the wrong data unit number and silently corrupts data.
> 
> The split size is already rounded down to the logical block size, so
> this is only possible when the data unit size is larger than it, e.g.
> a fscrypt filesystem with a 4K block size on a device with a 512-byte
> logical block size.
> 
> Fix this by rounding the split size down to a data unit boundary.  The
> split alignment becomes the maximum of the logical block size, the
> data unit size, and the zone write granularity, so a zoned write still
> meets all three requirements.
> 
> Split bios can be up to one data unit smaller than the queue limits
> allow, so a bio can be split a little more often.  The number of
> segments for the split bio is still counted up to the size before the
> rounding, so it can be larger than needed; it is only used for
> accounting.
> 
> Fixes: a892c8d52c02 ("block: Inline encryption support for blk-mq")
> Cc: stable@vger.kernel.org
> Signed-off-by: Baokun Li <libaokun@linux.alibaba.com>

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

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Sashiko AI review · https://sashiko.dev/#/patchset/20261011170958.1759230-1-libaokun@linux.alibaba.com?part=8