Change dm-writecache, so that it counts the number of blocks written
instead of the number of write bios. Bios can be split and requeued using
the dm_accept_partial_bio function, so counting of bios provided
inaccurate results.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Reported-by: Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>
Index: linux-2.6/drivers/md/dm-writecache.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-writecache.c
+++ linux-2.6/drivers/md/dm-writecache.c
@@ -1413,6 +1413,9 @@ static void writecache_bio_copy_ssd(stru
bio->bi_iter.bi_sector = start_cache_sec;
dm_accept_partial_bio(bio, bio_size >> SECTOR_SHIFT);
+ wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits;
+ wc->stats.writes_allocate += (bio->bi_iter.bi_size - wc->block_size) >> wc->block_size_bits;
+
if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
wc->uncommitted_blocks = 0;
queue_work(wc->writeback_wq, &wc->flush_work);
@@ -1428,9 +1431,10 @@ static enum wc_map_op writecache_map_wri
do {
bool found_entry = false;
bool search_used = false;
- wc->stats.writes++;
- if (writecache_has_error(wc))
+ if (writecache_has_error(wc)) {
+ wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits;
return WC_MAP_ERROR;
+ }
e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
if (e) {
if (!writecache_entry_is_committed(wc, e)) {
@@ -1454,9 +1458,10 @@ static enum wc_map_op writecache_map_wri
if (unlikely(!e)) {
if (!WC_MODE_PMEM(wc) && !found_entry) {
direct_write:
- wc->stats.writes_around++;
e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
writecache_map_remap_origin(wc, bio, e);
+ wc->stats.writes_around += bio->bi_iter.bi_size >> wc->block_size_bits;
+ wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits;
return WC_MAP_REMAP_ORIGIN;
}
wc->stats.writes_blocked_on_freelist++;
@@ -1470,6 +1475,7 @@ direct_write:
bio_copy:
if (WC_MODE_PMEM(wc)) {
bio_copy_block(wc, bio, memory_data(wc, e));
+ wc->stats.writes++;
} else {
writecache_bio_copy_ssd(wc, bio, e, search_used);
return WC_MAP_REMAP;
Index: linux-2.6/Documentation/admin-guide/device-mapper/writecache.rst
===================================================================
--- linux-2.6.orig/Documentation/admin-guide/device-mapper/writecache.rst
+++ linux-2.6/Documentation/admin-guide/device-mapper/writecache.rst
@@ -80,11 +80,11 @@ Status:
4. the number of blocks under writeback
5. the number of read blocks
6. the number of read blocks that hit the cache
-7. the number of write requests
-8. the number of write requests that hit uncommitted block
-9. the number of write requests that hit committed block
-10. the number of write requests that bypass the cache
-11. the number of write requests that are allocated in the cache
+7. the number of write blocks
+8. the number of write blocks that hit uncommitted block
+9. the number of write blocks that hit committed block
+10. the number of write blocks that bypass the cache
+11. the number of write blocks that are allocated in the cache
12. the number of write requests that are blocked on the freelist
13. the number of flush requests
14. the number of discard requests
--
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