md: override md superblock recovery_offset for journal device
Journal device stores data in a log structure. We need record the log
start. Here we override md superblock recovery_offset for this purpose.
This field of a journal device is meaningless otherwise.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 88dc631..2b0f62f 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -87,10 +87,16 @@
* array and could again if we did a partial
* resync from the bitmap
*/
- sector_t recovery_offset;/* If this device has been partially
+ union {
+ sector_t recovery_offset;/* If this device has been partially
* recovered, this is where we were
* up to.
*/
+ sector_t journal_tail; /* If this device is a journal device,
+ * this is the journal tail (journal
+ * recovery start point)
+ */
+ };
atomic_t nr_pending; /* number of pending requests.
* only maintained for arrays that