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authorMikulas Patocka <mpatocka@redhat.com>2021-06-21 21:48:29 +0300
committerMike Snitzer <snitzer@redhat.com>2021-06-21 23:15:10 +0300
commit867de40c4c23e6d7f89f9ce4272a5d1b1484c122 (patch)
treeebd3f7cb8dd216e4ab3f0ec96fc19565f52f35dc /drivers/md/dm-writecache.c
parentee55b92a7391bf871939330f662651b54be51b73 (diff)
downloadlinux-867de40c4c23e6d7f89f9ce4272a5d1b1484c122.tar.xz
dm writecache: write at least 4k when committing
SSDs perform badly with sub-4k writes (because they perfrorm read-modify-write internally), so make sure writecache writes at least 4k when committing. Fixes: 991bd8d7bc78 ("dm writecache: commit just one block, not a full page") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-writecache.c')
-rw-r--r--drivers/md/dm-writecache.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index ddd368e0491d..558d39764e6d 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -532,7 +532,11 @@ static void ssd_commit_superblock(struct dm_writecache *wc)
region.bdev = wc->ssd_dev->bdev;
region.sector = 0;
- region.count = wc->block_size >> SECTOR_SHIFT;
+ region.count = max(4096U, wc->block_size) >> SECTOR_SHIFT;
+
+ if (unlikely(region.sector + region.count > wc->metadata_sectors))
+ region.count = wc->metadata_sectors - region.sector;
+
region.sector += wc->start_sector;
req.bi_op = REQ_OP_WRITE;