[PATCH 3/7] dm writecache: verify watermark on resume

[Mikulas Patocka <mpatocka@redhat.com>]

[-- Attachment #1: dm-writecache-verify-watermark-after-resume.patch --]
[-- Type: text/plain, Size: 1542 bytes --]

Verify the watermark after resume - so that if the target is reloaded with
lower watermark, it will start the cleanup process immediatelly.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	#av4.18+
Fixes: 48debafe4f2f ("dm: add writecache target")

---
 drivers/md/dm-writecache.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/md/dm-writecache.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-writecache.c	2020-02-21 13:23:13.000000000 +0100
+++ linux-2.6/drivers/md/dm-writecache.c	2020-02-21 13:23:13.000000000 +0100
@@ -625,6 +625,12 @@ static void writecache_add_to_freelist(s
 	wc->freelist_size++;
 }
 
+static inline void writecache_verify_watermark(struct dm_writecache *wc)
+{
+	if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
+		queue_work(wc->writeback_wq, &wc->writeback_work);
+}
+
 static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc, sector_t expected_sector)
 {
 	struct wc_entry *e;
@@ -650,8 +656,8 @@ static struct wc_entry *writecache_pop_f
 		list_del(&e->lru);
 	}
 	wc->freelist_size--;
-	if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
-		queue_work(wc->writeback_wq, &wc->writeback_work);
+
+	writecache_verify_watermark(wc);
 
 	return e;
 }
@@ -965,6 +971,8 @@ erase_this:
 		writecache_commit_flushed(wc, false);
 	}
 
+	writecache_verify_watermark(wc);
+
 	wc_unlock(wc);
 }