[PATCH] md: improve raid1 "IO Barrier" concept
raid1 needs to put up a barrier to new requests while it does resync or other
background recovery. The code for this is currently open-coded, slighty
obscure by its use of two waitqueues, and not documented.
This patch gathers all the related code into 4 functions, and includes a
comment which (hopefully) explains what is happening.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/raid/raid1.h b/include/linux/raid/raid1.h
index 292b98f..c556742 100644
--- a/include/linux/raid/raid1.h
+++ b/include/linux/raid/raid1.h
@@ -45,6 +45,7 @@
spinlock_t resync_lock;
int nr_pending;
+ int nr_waiting;
int barrier;
sector_t next_resync;
int fullsync; /* set to 1 if a full sync is needed,
@@ -52,8 +53,7 @@
* Cleared when a sync completes.
*/
- wait_queue_head_t wait_idle;
- wait_queue_head_t wait_resume;
+ wait_queue_head_t wait_barrier;
struct pool_info *poolinfo;