Re: [Qemu-block] [Qemu-devel] [PATCH v4 12/23] block: Convert bdrv_get_block_status_above() to bytes

[John Snow]

On 09/13/2017 12:03 PM, Eric Blake wrote:
> We are gradually moving away from sector-based interfaces, towards
> byte-based.  In the common case, allocation is unlikely to ever use
> values that are not naturally sector-aligned, but it is possible
> that byte-based values will let us be more precise about allocation
> at the end of an unaligned file that can do byte-based access.
> 
> Changing the name of the function from bdrv_get_block_status_above()
> to bdrv_block_status_above() ensures that the compiler enforces that
> all callers are updated.  For now, the io.c layer still assert()s
> that all callers are sector-aligned, but that can be relaxed when a
> later patch implements byte-based block status in the drivers.
> 
> For the most part this patch is just the addition of scaling at the
> callers followed by inverse scaling at bdrv_block_status().  But some
> code, particularly bdrv_block_status(), gets a lot simpler because
> it no longer has to mess with sectors.  Likewise, mirror code no
> longer computes s->granularity >> BDRV_SECTOR_BITS, and can therefore
> drop an assertion (fix a neighboring assertion to use is_power_of_2
> while there).
> 

Huh, I suppose so, yeah. Do you have a test that covers what happens in
this newly available use case?

> For ease of review, bdrv_get_block_status() was tackled separately.
> 
> Signed-off-by: Eric Blake <address@hidden>
> 

Looks mechanically correct, anyway.

Reviewed-by: John Snow <address@hidden>