MD: add sync_super to mddev_t struct

Add the 'sync_super' function pointer to MD array structure (struct mddev_s)

If device-mapper (dm-raid.c) is to define its own on-disk superblock and be
able to load it, there must still be a way for MD to initiate superblock
updates.  The simplest way to make this happen is to provide a pointer in
the MD array structure that can be set by device-mapper (or other module)
with a function to do this.  If the function has been set, it will be used;
otherwise, the method with be looked up via 'super_types' as usual.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 0b1fd3f1d85b..5e35535ab7c3 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -330,6 +330,7 @@ struct mddev_s
 	atomic_t flush_pending;
 	struct work_struct flush_work;
 	struct work_struct event_work;	/* used by dm to report failure event */
+	void (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
 };