dm integrity: always set version on superblock update

The new integrity bitmap mode uses the dirty flag.  The dirty flag
should not be set in older superblock versions.

The current code sets it unconditionally, even if the superblock
was already formatted without bitmap in older system.

Fix this by moving the version check to one common place and check
version on every superblock write.
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-integrity.c

@@ -476,6 +476,9 @@ static int sync_rw_sb(struct dm_integrity_c *ic, int op, int op_flags)
 	io_loc.sector = ic->start;
 	io_loc.count = SB_SECTORS;
 
+	if (op == REQ_OP_WRITE)
+		sb_set_version(ic);
+
 	return dm_io(&io_req, 1, &io_loc, NULL);
 }
 
@@ -2317,7 +2320,6 @@ static void recalc_write_super(struct dm_integrity_c *ic)
 	if (dm_integrity_failed(ic))
 		return;
 
-	sb_set_version(ic);
 	r = sync_rw_sb(ic, REQ_OP_WRITE, 0);
 	if (unlikely(r))
 		dm_integrity_io_error(ic, "writing superblock", r);