1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 87430fea2875..cb036868a9e9 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -292,6 +292,17 @@ struct mddev_s
         struct mutex                    bitmap_mutex;
 
         struct list_head                all_mddevs;
+
+        /* Generic barrier handling.
+         * If there is a pending barrier request, all other
+         * writes are blocked while the devices are flushed.
+         * The last to finish a flush schedules a worker to
+         * submit the barrier request (without the barrier flag),
+         * then submit more flush requests.
+         */
+        struct bio *barrier;
+        atomic_t flush_pending;
+        struct work_struct barrier_work;
 };
 
 
@@ -432,6 +443,7 @@ extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
 
 extern int mddev_congested(mddev_t *mddev, int bits);
+extern void md_barrier_request(mddev_t *mddev, struct bio *bio);
 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
                            sector_t sector, int size, struct page *page);
 extern void md_super_wait(mddev_t *mddev);