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authorNeilBrown <neilb@suse.de>2009-03-31 07:39:39 +0400
committerNeilBrown <neilb@suse.de>2009-03-31 07:39:39 +0400
commit245f46c2c221ef09c7db892f0e3fc2149be42052 (patch)
treebe7e6f4b7b65b682c43e59ef17f7ed580bc8a82b /drivers/md/md.h
parent409c57f3801701dfee27a28103dda4831306cb20 (diff)
downloadlinux-245f46c2c221ef09c7db892f0e3fc2149be42052.tar.xz
md: add ->takeover method to support changing the personality managing an array
Implement this for RAID6 to be able to 'takeover' a RAID5 array. The new RAID6 will use a layout which places Q on the last device, and that device will be missing. If there are any available spares, one will immediately have Q recovered onto it. Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/md.h')
-rw-r--r--drivers/md/md.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 84b22d67ba14..8034f62a9d28 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -321,6 +321,16 @@ struct mdk_personality
* others - reserved
*/
void (*quiesce) (mddev_t *mddev, int state);
+ /* takeover is used to transition an array from one
+ * personality to another. The new personality must be able
+ * to handle the data in the current layout.
+ * e.g. 2drive raid1 -> 2drive raid5
+ * ndrive raid5 -> degraded n+1drive raid6 with special layout
+ * If the takeover succeeds, a new 'private' structure is returned.
+ * This needs to be installed and then ->run used to activate the
+ * array.
+ */
+ void *(*takeover) (mddev_t *mddev);
};