dm raid: correct resizing state relative to reshape space in ctr

Pay attention to existing reshape space to define if a raid set needs
resizing.  Otherwise we can hit "Can't resize a reshaping raid set"
when a reshape is being requested.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-raid.c

@@ -2969,10 +2969,10 @@ static void configure_discard_support(struct raid_set *rs)
 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
 	int r;
-	bool resize;
+	bool resize = false;
 	struct raid_type *rt;
 	unsigned int num_raid_params, num_raid_devs;
-	sector_t calculated_dev_sectors, rdev_sectors;
+	sector_t calculated_dev_sectors, rdev_sectors, reshape_sectors;
 	struct raid_set *rs = NULL;
 	const char *arg;
 	struct rs_layout rs_layout;
@@ -3055,7 +3055,10 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
-	resize = calculated_dev_sectors != rdev_sectors;
+
+	reshape_sectors = _get_reshape_sectors(rs);
+	if (calculated_dev_sectors != rdev_sectors)
+		resize = calculated_dev_sectors != (reshape_sectors ? rdev_sectors - reshape_sectors : rdev_sectors);
 
 	INIT_WORK(&rs->md.event_work, do_table_event);
 	ti->private = rs;
@@ -3178,7 +3181,6 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	mddev_lock_nointr(&rs->md);
 	r = md_run(&rs->md);
 	rs->md.in_sync = 0; /* Assume already marked dirty */
-
 	if (r) {
 		ti->error = "Failed to run raid array";
 		mddev_unlock(&rs->md);