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>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8d93f86..3c6eaab 100644 (file)
--- 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.
                 */