1 files changed, 17 insertions, 0 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 53875ae73ad4..3c5f2fcd82c1 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -142,6 +142,7 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
         unsigned long limit;
         unsigned long last_waited = 0;
         int force_reg = 0;
+        int sync_pending;
         struct blk_plug plug;
 
         /*
@@ -229,6 +230,22 @@ loop_lock:
 
                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 
+                /*
+                 * if we're doing the sync list, record that our
+                 * plug has some sync requests on it
+                 *
+                 * If we're doing the regular list and there are
+                 * sync requests sitting around, unplug before
+                 * we add more
+                 */
+                if (pending_bios == &device->pending_sync_bios) {
+                        sync_pending = 1;
+                } else if (sync_pending) {
+                        blk_finish_plug(&plug);
+                        blk_start_plug(&plug);
+                        sync_pending = 0;
+                }
+
                 submit_bio(cur->bi_rw, cur);
                 num_run++;
                 batch_run++;