[Devel] [PATCH VZ10 0/6] dm-qcow: lseek improvements

Pavel Tikhomirov ptikhomirov at virtuozzo.com
Fri Aug 14 14:55:47 MSK 2026


Looks reasonable, not gonna lie I don't fully understand last patch.

So except for specific comments to patches:

Reviewed-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

On 8/10/26 14:29, Andrey Zhadchenko wrote:
> This patchset is mostly about improving dm-qcow2 lseek speed. L2 md
> pages can now be scanned in batch with simple for() instead of heavy
> parse_metadata(). Seek qios for backing images are now called with
> a range bigger than 1 cluster if possible.
> Also fix a few clamping bugs and use correct comparison for seek
> modes.
> 
> Andrey Zhadchenko (6):
>   drivers/md/dm-qcow2: fix lower delta seek window clamp
>   drivers/md/dm-qcow2: keep seek parse window within limit
>   drivers/md/dm-qcow2: fix seek constant comparison
>   drivers/md/dm-qcow2: fix seek skip to the next L2 table
>   drivers/md/dm-qcow2: scan lower delta in one pass over empty L1 entry
>   drivers/md/dm-qcow2: seek unallocated L2 entries in one pass within md
> 
>  drivers/md/dm-qcow2-map.c | 111 ++++++++++++++++++++++++++------------
>  1 file changed, 78 insertions(+), 33 deletions(-)
> 

-- 
Best regards, Pavel Tikhomirov
Senior Software Developer, Virtuozzo.



More information about the Devel mailing list