From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Tikhomirov Date: Mon, 24 Aug 2026 16:38:41 +0200 Subject: Re: [Devel] [PATCH VZ10 v2 0/7] dm-qcow: lseek improvements In-Reply-To: <20260819000745.28823-1-andrey.zhadchenko@virtuozzo.com> References: <20260819000745.28823-1-andrey.zhadchenko@virtuozzo.com> Message-ID: List-Id: Reviewed-by: Pavel Tikhomirov On 8/19/26 02:07, 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. > > v2: > - patch #4 "fix seek skip to the next L2 table" > - changed l2 calculation to a simplier round_up > - allow l2 skip if the backing data does not exist (e.g. lower is > shorter) > - patch #6 "seek unallocated L2 entries in one pass within md" > - add forgotten to_sector() when skipping unallocated entries > - NEW patch #7 adressing patch #5 edge case when we do to_sector(end), > where 'end' may be not sector aligned, thus causing endless loop. > > Andrey Zhadchenko (7): > 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: forbid unaligned virtual size for images > > drivers/md/dm-qcow2-map.c | 117 ++++++++++++++++++++++++----------- > drivers/md/dm-qcow2-target.c | 1 + > 2 files changed, 82 insertions(+), 36 deletions(-) > -- Best regards, Pavel Tikhomirov Senior Software Developer, Virtuozzo.