On 6/18/25 2:07 PM, John Garry wrote:
> The atomic write unit max value is limited by any stacked device stripe
> size.
>
> It is required that the atomic write unit is a power-of-2 factor of the
> stripe size.
>
> Currently we use io_min limit to hold the stripe size, and check for a
> io_min <= SECTOR_SIZE when deciding if we have a striped stacked device.
>
> Nilay reports that this causes a problem when the physical block size is
> greater than SECTOR_SIZE [0].
>
> Furthermore, io_min may be mutated when stacking devices, and this makes
> it a poor candidate to hold the stripe size. Such an example (of when
> io_min may change) would be when the io_min is less than the physical
> block size.
>
> Use chunk_sectors to hold the stripe size, which is more appropriate.
>
> [0]
> https://lore.kernel.org/linux-block/888f3b1d-7817-4007-b3b3-1a2ea04df...@linux.ibm.com/T/#mecca17129f72811137d3c2f1e477634e77f06781
>
> Signed-off-by: John Garry <john.g.ga...@oracle.com>
Looks good to me:
Reviewed-by: Nilay Shroff <ni...@linux.ibm.com>
