md: refine reporting of resync/reshape delays.

If 'resync_max' is set to 0 (as is often done when starting a
reshape, so the mdadm can remain in control during a sensitive
period), and if the reshape request is initially delayed because
another array using the same array is resyncing or reshaping etc,
when user-space cannot easily tell when the delay changes from being
due to a conflicting reshape, to being due to resync_max = 0.

So introduce a new state: (curr_resync == 3) to reflect this, make
sure it is visible both via /proc/mdstat and via the "sync_completed"
sysfs attribute, and ensure that the event transition from one delay
state to the other is properly notified.

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

1 files changed, 18 insertions, 7 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8d93f867adbf..3c6eaab0b6ce 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4400,6 +4400,10 @@ sync_completed_show(struct mddev *mddev, char *page)
         if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
                 return sprintf(page, "none\n");
 
+        if (mddev->curr_resync == 1 ||
+            mddev->curr_resync == 2)
+                return sprintf(page, "delayed\n");
+
         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
             test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
                 max_sectors = mddev->resync_max_sectors;
@@ -6807,7 +6811,11 @@ static void status_resync(struct seq_file *seq, struct mddev * mddev)
         int scale;
         unsigned int per_milli;
 
-        resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);
+        if (mddev->curr_resync <= 3)
+                resync = 0;
+        else
+                resync = mddev->curr_resync
+                        - atomic_read(&mddev->recovery_active);
 
         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
             test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
@@ -7033,7 +7041,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
                                 if (mddev->curr_resync > 2) {
                                         status_resync(seq, mddev);
                                         seq_printf(seq, "\n      ");
-                                } else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
+                                } else if (mddev->curr_resync >= 1)
                                         seq_printf(seq, "\tresync=DELAYED\n      ");
                                 else if (mddev->recovery_cp < MaxSector)
                                         seq_printf(seq, "\tresync=PENDING\n      ");
@@ -7423,8 +7431,11 @@ void md_do_sync(struct md_thread *thread)
                        "md: resuming %s of %s from checkpoint.\n",
                        desc, mdname(mddev));
                 mddev->curr_resync = j;
-        }
+        } else
+                mddev->curr_resync = 3; /* no longer delayed */
         mddev->curr_resync_completed = j;
+        sysfs_notify(&mddev->kobj, NULL, "sync_completed");
+        md_new_event(mddev);
 
         blk_start_plug(&plug);
         while (j < max_sectors) {
@@ -7477,7 +7488,8 @@ void md_do_sync(struct md_thread *thread)
                         break;
 
                 j += sectors;
-                if (j>1) mddev->curr_resync = j;
+                if (j > 2)
+                        mddev->curr_resync = j;
                 mddev->curr_mark_cnt = io_sectors;
                 if (last_check == 0)
                         /* this is the earliest that rebuild will be
@@ -7599,8 +7611,6 @@ static int remove_and_add_spares(struct mddev *mddev)
         int spares = 0;
         int removed = 0;
 
-        mddev->curr_resync_completed = 0;
-
         rdev_for_each(rdev, mddev)
                 if (rdev->raid_disk >= 0 &&
                     !test_bit(Blocked, &rdev->flags) &&
@@ -7791,6 +7801,7 @@ void md_check_recovery(struct mddev *mddev)
                 /* Set RUNNING before clearing NEEDED to avoid
                  * any transients in the value of "sync_action".
                  */
+                mddev->curr_resync_completed = 0;
                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
                 /* Clear some bits that don't mean anything, but
                  * might be left set
@@ -7804,7 +7815,7 @@ void md_check_recovery(struct mddev *mddev)
                 /* no recovery is running.
                  * remove any failed drives, then
                  * add spares if possible.
-                 * Spare are also removed and re-added, to allow
+                 * Spares are also removed and re-added, to allow
                  * the personality to fail the re-add.
                  */