md: allow v0.91 metadata to record devices as being active but not in-sync.

This is a combination that didn't really make sense before.
However when a reshape is converting e.g. raid5 -> raid6, the extra
device is not fully in-sync, but is certainly active and contains
important data.
So allow that start to be meaningful and in particular get
the 'recovery_offset' value (which is needed for any non-in-sync
active device) from the reshape_position.

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

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 01b9a0f..b182f86 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -944,6 +944,14 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                            desc->raid_disk < mddev->raid_disks */) {
                        set_bit(In_sync, &rdev->flags);
                        rdev->raid_disk = desc->raid_disk;
+               } else if (desc->state & (1<<MD_DISK_ACTIVE)) {
+                       /* active but not in sync implies recovery up to
+                        * reshape position.  We don't know exactly where
+                        * that is, so set to zero for now */
+                       if (mddev->minor_version >= 91) {
+                               rdev->recovery_offset = 0;
+                               rdev->raid_disk = desc->raid_disk;
+                       }
                }
                if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
                        set_bit(WriteMostly, &rdev->flags);
@@ -1032,8 +1040,19 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
        list_for_each_entry(rdev2, &mddev->disks, same_set) {
                mdp_disk_t *d;
                int desc_nr;
-               if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
-                   && !test_bit(Faulty, &rdev2->flags))
+               int is_active = test_bit(In_sync, &rdev2->flags);
+
+               if (rdev2->raid_disk >= 0 &&
+                   sb->minor_version >= 91)
+                       /* we have nowhere to store the recovery_offset,
+                        * but if it is not below the reshape_position,
+                        * we can piggy-back on that.
+                        */
+                       is_active = 1;
+               if (rdev2->raid_disk < 0 ||
+                   test_bit(Faulty, &rdev2->flags))
+                       is_active = 0;
+               if (is_active)
                        desc_nr = rdev2->raid_disk;
                else
                        desc_nr = next_spare++;
@@ -1043,16 +1062,16 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
                d->number = rdev2->desc_nr;
                d->major = MAJOR(rdev2->bdev->bd_dev);
                d->minor = MINOR(rdev2->bdev->bd_dev);
-               if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
-                   && !test_bit(Faulty, &rdev2->flags))
+               if (is_active)
                        d->raid_disk = rdev2->raid_disk;
                else
                        d->raid_disk = rdev2->desc_nr; /* compatibility */
                if (test_bit(Faulty, &rdev2->flags))
                        d->state = (1<<MD_DISK_FAULTY);
-               else if (test_bit(In_sync, &rdev2->flags)) {
+               else if (is_active) {
                        d->state = (1<<MD_DISK_ACTIVE);
-                       d->state |= (1<<MD_DISK_SYNC);
+                       if (test_bit(In_sync, &rdev2->flags))
+                               d->state |= (1<<MD_DISK_SYNC);
                        active++;
                        working++;
                } else {