[PATCH] md: all hot-add and hot-remove of md intent logging bitmaps

Both file-bitmaps and superblock bitmaps are supported.

If you add a bitmap file on the array device, you lose.

This introduces a 'default_bitmap_offset' field in mddev, as the ioctl used
for adding a superblock bitmap doesn't have room for giving an offset.  Later,
this value will be setable via sysfs.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/raid/md_k.h

@@ -278,6 +278,10 @@ struct mddev_s
 							* start of bitmap. May be
 							* negative, but not '0'
 							*/
+	long				default_bitmap_offset; /* this is the offset to use when
+								* hot-adding a bitmap.  It should
+								* eventually be settable by sysfs.
+								*/
 
 	struct list_head		all_mddevs;
 };
@@ -314,6 +318,12 @@ struct mdk_personality_s
 	int (*resize) (mddev_t *mddev, sector_t sectors);
 	int (*reshape) (mddev_t *mddev, int raid_disks);
 	int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
+	/* quiesce moves between quiescence states
+	 * 0 - fully active
+	 * 1 - no new requests allowed
+	 * others - reserved
+	 */
+	void (*quiesce) (mddev_t *mddev, int state);
 };