Make sure all changes to md/sync_action are notified.

When the 'resync' thread starts or stops, when we explicitly
set sync_action, or when we determine that there is definitely nothing
to do, we notify sync_action.

To stop "sync_action" from occasionally showing the wrong value,
we introduce a new flags - MD_RECOVERY_RECOVER - to say that a
recovery is probably needed or happening, and we make sure
that we set MD_RECOVERY_RUNNING before clearing MD_RECOVERY_NEEDED.

Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 28 insertions, 6 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5b9d4fe4e6e..c26dcad8a3a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -169,7 +169,6 @@ void md_new_event(mddev_t *mddev)
 {
         atomic_inc(&md_event_count);
         wake_up(&md_event_waiters);
-        sysfs_notify(&mddev->kobj, NULL, "sync_action");
 }
 EXPORT_SYMBOL_GPL(md_new_event);
 
@@ -2936,7 +2935,7 @@ action_show(mddev_t *mddev, char *page)
                                 type = "check";
                         else
                                 type = "repair";
-                } else
+                } else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
                         type = "recover";
         }
         return sprintf(page, "%s\n", type);
@@ -2958,9 +2957,12 @@ action_store(mddev_t *mddev, const char *page, size_t len)
         } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
                    test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
                 return -EBUSY;
-        else if (cmd_match(page, "resync") || cmd_match(page, "recover"))
+        else if (cmd_match(page, "resync"))
+                set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+        else if (cmd_match(page, "recover")) {
+                set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
-        else if (cmd_match(page, "reshape")) {
+        } else if (cmd_match(page, "reshape")) {
                 int err;
                 if (mddev->pers->start_reshape == NULL)
                         return -EINVAL;
@@ -2977,6 +2979,7 @@ action_store(mddev_t *mddev, const char *page, size_t len)
         }
         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
         md_wakeup_thread(mddev->thread);
+        sysfs_notify(&mddev->kobj, NULL, "sync_action");
         return len;
 }
 
@@ -3682,6 +3685,7 @@ static int do_md_run(mddev_t * mddev)
         mddev->changed = 1;
         md_new_event(mddev);
         sysfs_notify(&mddev->kobj, NULL, "array_state");
+        sysfs_notify(&mddev->kobj, NULL, "sync_action");
         kobject_uevent(&mddev->gendisk->dev.kobj, KOBJ_CHANGE);
         return 0;
 }
@@ -4252,6 +4256,8 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
                         export_rdev(rdev);
 
                 md_update_sb(mddev, 1);
+                if (mddev->degraded)
+                        set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                 md_wakeup_thread(mddev->thread);
                 return err;
@@ -5105,6 +5111,8 @@ void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
         if (!mddev->pers->error_handler)
                 return;
         mddev->pers->error_handler(mddev,rdev);
+        if (mddev->degraded)
+                set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
         md_wakeup_thread(mddev->thread);
@@ -6055,13 +6063,18 @@ void md_check_recovery(mddev_t *mddev)
                         mddev->recovery = 0;
                         /* flag recovery needed just to double check */
                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+                        sysfs_notify(&mddev->kobj, NULL, "sync_action");
                         md_new_event(mddev);
                         goto unlock;
                 }
+                /* Set RUNNING before clearing NEEDED to avoid
+                 * any transients in the value of "sync_action".
+                 */
+                set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+                clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                 /* Clear some bits that don't mean anything, but
                  * might be left set
                  */
-                clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                 clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
                 clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
 
@@ -6079,17 +6092,19 @@ void md_check_recovery(mddev_t *mddev)
                                 /* Cannot proceed */
                                 goto unlock;
                         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
+                        clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
                 } else if ((spares = remove_and_add_spares(mddev))) {
                         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
                         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+                        set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
                 } else if (mddev->recovery_cp < MaxSector) {
                         set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+                        clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
                 } else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
                         /* nothing to be done ... */
                         goto unlock;
 
                 if (mddev->pers->sync_request) {
-                        set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
                         if (spares && mddev->bitmap && ! mddev->bitmap->file) {
                                 /* We are adding a device or devices to an array
                                  * which has the bitmap stored on all devices.
@@ -6108,9 +6123,16 @@ void md_check_recovery(mddev_t *mddev)
                                 mddev->recovery = 0;
                         } else
                                 md_wakeup_thread(mddev->sync_thread);
+                        sysfs_notify(&mddev->kobj, NULL, "sync_action");
                         md_new_event(mddev);
                 }
         unlock:
+                if (!mddev->sync_thread) {
+                        clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+                        if (test_and_clear_bit(MD_RECOVERY_RECOVER,
+                                               &mddev->recovery))
+                                sysfs_notify(&mddev->kobj, NULL, "sync_action");
+                }
                 mddev_unlock(mddev);
         }
 }