dm writecache: fix performance degradation in ssd mode

Fix a thinko in ssd_commit_superblock. region.count is in sectors, not
bytes. This bug doesn't corrupt data, but it causes performance
degradation.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: dc8a01ae1d ("dm writecache: optimize superblock write")
Cc: stable@vger.kernel.org # v5.7+
Reported-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2021-01-23 09:19:56 -05:00 committed by Mike Snitzer
parent 09d85f8d89
commit cb728484a7

View File

@ -523,7 +523,7 @@ static void ssd_commit_superblock(struct dm_writecache *wc)
region.bdev = wc->ssd_dev->bdev; region.bdev = wc->ssd_dev->bdev;
region.sector = 0; region.sector = 0;
region.count = PAGE_SIZE; region.count = PAGE_SIZE >> SECTOR_SHIFT;
if (unlikely(region.sector + region.count > wc->metadata_sectors)) if (unlikely(region.sector + region.count > wc->metadata_sectors))
region.count = wc->metadata_sectors - region.sector; region.count = wc->metadata_sectors - region.sector;