diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 58a6403780aa..1f192a581fb2 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -468,12 +468,12 @@ static bool inode_do_switch_wbs(struct inode *inode,
 		if (inode_state_read(inode) & I_DIRTY_ALL) {
 			/*
 			 * We need to keep b_dirty list sorted by
-			 * dirtied_time_when. However properly sorting the
+			 * dirtied_when. However properly sorting the
 			 * inode in the list gets too expensive when switching
 			 * many inodes. So just attach inode at the end of the
-			 * dirty list and clobber the dirtied_time_when.
+			 * dirty list and clobber the dirtied_when.
 			 */
-			inode->dirtied_time_when = jiffies;
+			inode->dirtied_when = jiffies;
 			inode_io_list_move_locked(inode, new_wb,
 						  &new_wb->b_dirty);
 		} else {
@@ -566,6 +566,7 @@ static void process_inode_switch_wbs(struct bdi_writeback *new_wb,
 		}
 	}
 
+	wb_io_lists_depopulated(old_wb);
 	spin_unlock(&new_wb->list_lock);
 	spin_unlock(&old_wb->list_lock);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a5585872e48c..b5485f2c1f2b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -815,7 +815,9 @@ struct inode {
 	/* 32-bit hole */
 	struct rw_semaphore	i_rwsem;
 
-	unsigned long		dirtied_when;	/* jiffies of first dirtying */
+	/* Timestamp for writeback list ordering and age checks (jiffies). */
+	unsigned long		dirtied_when;
+	/* Start time for deciding when lazytime updates need writeback (jiffies). */
 	unsigned long		dirtied_time_when;
 
 	struct hlist_node	i_hash;