1 files changed, 26 insertions, 2 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 1791134cf477..bcb143396fe0 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -23,6 +23,7 @@
 #define DEFERRED_SET_SIZE 64
 #define MAPPING_POOL_SIZE 1024
 #define PRISON_CELLS 1024
+#define COMMIT_PERIOD HZ
 
 /*
  * The block size of the device holding pool data must be
@@ -520,8 +521,10 @@ struct pool {
 
         struct workqueue_struct *wq;
         struct work_struct worker;
+        struct delayed_work waker;
 
         unsigned ref_count;
+        unsigned long last_commit_jiffies;
 
         spinlock_t lock;
         struct bio_list deferred_bios;
@@ -1271,6 +1274,12 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
         }
 }
 
+static int need_commit_due_to_time(struct pool *pool)
+{
+        return jiffies < pool->last_commit_jiffies ||
+               jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
+}
+
 static void process_deferred_bios(struct pool *pool)
 {
         unsigned long flags;
@@ -1312,7 +1321,7 @@ static void process_deferred_bios(struct pool *pool)
         bio_list_init(&pool->deferred_flush_bios);
         spin_unlock_irqrestore(&pool->lock, flags);
 
-        if (bio_list_empty(&bios))
+        if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
                 return;
 
         r = dm_pool_commit_metadata(pool->pmd);
@@ -1323,6 +1332,7 @@ static void process_deferred_bios(struct pool *pool)
                         bio_io_error(bio);
                 return;
         }
+        pool->last_commit_jiffies = jiffies;
 
         while ((bio = bio_list_pop(&bios)))
                 generic_make_request(bio);
@@ -1336,6 +1346,17 @@ static void do_worker(struct work_struct *ws)
         process_deferred_bios(pool);
 }
 
+/*
+ * We want to commit periodically so that not too much
+ * unwritten data builds up.
+ */
+static void do_waker(struct work_struct *ws)
+{
+        struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
+        wake_worker(pool);
+        queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
+}
+
 /*----------------------------------------------------------------*/
 
 /*
@@ -1545,6 +1566,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
         }
 
         INIT_WORK(&pool->worker, do_worker);
+        INIT_DELAYED_WORK(&pool->waker, do_waker);
         spin_lock_init(&pool->lock);
         bio_list_init(&pool->deferred_bios);
         bio_list_init(&pool->deferred_flush_bios);
@@ -1571,6 +1593,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
                 goto bad_endio_hook_pool;
         }
         pool->ref_count = 1;
+        pool->last_commit_jiffies = jiffies;
         pool->pool_md = pool_md;
         pool->md_dev = metadata_dev;
         __pool_table_insert(pool);
@@ -1900,7 +1923,7 @@ static void pool_resume(struct dm_target *ti)
         __requeue_bios(pool);
         spin_unlock_irqrestore(&pool->lock, flags);
 
-        wake_worker(pool);
+        do_waker(&pool->waker.work);
 }
 
 static void pool_postsuspend(struct dm_target *ti)
@@ -1909,6 +1932,7 @@ static void pool_postsuspend(struct dm_target *ti)
         struct pool_c *pt = ti->private;
         struct pool *pool = pt->pool;
 
+        cancel_delayed_work(&pool->waker);
         flush_workqueue(pool->wq);
 
         r = dm_pool_commit_metadata(pool->pmd);