Re: [Qemu-block] [Qemu-devel] [PATCH v4 08/23] block: Switch bdrv_co_get_block_status() to byte-based

[John Snow]

On 09/13/2017 12:03 PM, Eric Blake wrote:
> We are gradually converting to byte-based interfaces, as they are
> easier to reason about than sector-based.  Convert another internal
> function (no semantic change); and as with its public counterpart,
> rename to bdrv_co_block_status() to make the compiler enforce that
> we catch all uses.  For now, we assert that callers still pass
> aligned data, but ultimately, this will be the function where we
> hand off to a byte-based driver callback, and will eventually need
> to add logic to ensure we round calls according to the driver's
> request_alignment then touch up the result handed back to the
> caller, to start permitting a caller to pass unaligned offsets.
> 
> Note that we are now prepared to accepts 'bytes' larger than INT_MAX;
> this is okay as long as we clamp things internally before violating
> any 32-bit limits, and makes no difference to how a client will
> use the information (clients looping over the entire file must
> already be prepared for consecutive calls to return the same status,
> as drivers are already free to return shorter-than-maximal status
> due to any other convenient split points, such as when the L2 table
> crosses cluster boundaries in qcow2).
> 
> Signed-off-by: Eric Blake <address@hidden>


Reviewed-by: John Snow <address@hidden>