[Devel] [PATCH VZ9 v2 0/3] improve pio submission suspension

[Pavel Tikhomirov]

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

On 7/16/25 17:37, Andrey Zhadchenko wrote:
> Recently we encountered EBUSY errors while trying to resize ploop
> devices under load. This mostly happens because we are not waiting
> in-progess IO correctly:
>   - initial pio is removed from inflight even if its split pios are
> still running
>   - there are no wait for metadata writeback
> 
> This patchset fixes that by moving inflight decrease later and
> introducing new counter for inflight metadata writeback.
> 
> Note that for dm-qcow2 patches are not needed: it does not have
> delayed metadata writeback and inflight countera are decreased
> correctly at the time of endio_cb
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-108540
> 
> v2:
>   - removed excessive ploop_inflight_bios_ref_switch()
> 
> Andrey Zhadchenko (3):
>    drivers/md/ploop: drop excessive wb delay disable during resize
>    drivers/md/ploop: add inflight metadata writeback counter
>    drivers/md/ploop: decrease inflight number after pio endio
> 
>   drivers/md/dm-ploop-cmd.c    |  9 ++++++---
>   drivers/md/dm-ploop-map.c    | 11 ++++++++++-
>   drivers/md/dm-ploop-target.c |  2 ++
>   drivers/md/dm-ploop.h        |  3 +++
>   4 files changed, 21 insertions(+), 4 deletions(-)
> 

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