diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index f0436eea1544..739984462677 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -1411,6 +1411,13 @@ static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
  *   This is where we reclaim all of the pinned space generated by running the
  *   iputs
  *
+ * RECLAIM_ZONES
+ *   This state only works for the zoned mode. We scan the block groups in the
+ *   reclaim_bgs_list and check if we can relocate them. If yes perform the
+ *   relocation to garbage collect the zone. On each of these runs
+ *   BTRFS_ZONED_SYNC_RECLAIM_BATCH (5) block-groups will be reclaimed, after all
+ *   unused block-groups have been deleted.
+ *
  * RESET_ZONES
  *   This state works only for the zoned mode. We scan the unused block group
  *   list and reset the zones and reuse the block group.