From: Yu Kuai <yukuai3@xxxxxxxxxx>
In order to make code related to sync_thread cleaner in following
patches, also add detail comment about each sync action.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md.h | 57 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 56 insertions(+), 1 deletion(-)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 2a1cb7b889e5..2edad966f90a 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -34,6 +34,61 @@
*/
#define MD_FAILFAST (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT)
+/* Status of sync thread. */
+enum sync_action {
+ /*
+ * Represent by MD_RECOVERY_SYNC, start when:
+ * 1) after assemble, sync data from first rdev to other copies, this
+ * must be done first before other sync actions and will only execute
+ * once;
+ * 2) resize the array(notice that this is not reshape), sync data for
+ * the new range;
+ */
+ ACTION_RESYNC,
+ /*
+ * Represent by MD_RECOVERY_RECOVER, start when:
+ * 1) for new replacement, sync data based on the replace rdev or
+ * available copies from other rdev;
+ * 2) for new member disk while the array is degraded, sync data from
+ * other rdev;
+ * 3) reassemble after power failure or re-add a hot removed rdev, sync
+ * data from first rdev to other copies based on bitmap;
+ */
+ ACTION_RECOVER,
+ /*
+ * Represent by MD_RECOVERY_SYNC | MD_RECOVERY_REQUESTED |
+ * MD_RECOVERY_CHECK, start when user echo "check" to sysfs api
+ * sync_action, used to check if data copies from differenct rdev are
+ * the same. The number of mismatch sectors will be exported to user
+ * by sysfs api mismatch_cnt;
+ */
+ ACTION_CHECK,
+ /*
+ * Represent by MD_RECOVERY_SYNC | MD_RECOVERY_REQUESTED, start when
+ * user echo "repair" to sysfs api sync_action, usually paired with
+ * ACTION_CHECK, used to force syncing data once user found that there
+ * are inconsistent data,
+ */
+ ACTION_REPAIR,
+ /*
+ * Represent by MD_RECOVERY_RESHAPE, start when new member disk is added
+ * to the conf, notice that this is different from spares or
+ * replacement;
+ */
+ ACTION_RESHAPE,
+ /*
+ * Represent by MD_RECOVERY_FROZEN, can be set by sysfs api sync_action
+ * or internal usage like setting the array read-only, will forbid above
+ * actions.
+ */
+ ACTION_FROZEN,
+ /*
+ * All above actions don't match.
+ */
+ ACTION_IDLE,
+ NR_SYNC_ACTIONS,
+};
+
/*
* The struct embedded in rdev is used to serialize IO.
*/
@@ -571,7 +626,7 @@ enum recovery_flags {
/* interrupted because io-error */
MD_RECOVERY_ERROR,
- /* flags determines sync action */
+ /* flags determines sync action, see details in enum sync_action */
/* if just this flag is set, action is resync. */
MD_RECOVERY_SYNC,
--
2.39.2
