--- x/fs/ext4/inode.c
+++ y/fs/ext4/inode.c
@@ -4573,6 +4573,7 @@ int ext4_truncate(struct inode *inode)
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	unsigned int credits;
 	int err = 0, err2;
+	static int subclass = 0;
 	handle_t *handle;
 	struct address_space *mapping = inode->i_mapping;
 
@@ -4636,7 +4637,7 @@ int ext4_truncate(struct inode *inode)
 	ext4_fc_track_inode(handle, inode);
 	ext4_check_map_extents_env(inode);
 
-	down_write(&EXT4_I(inode)->i_data_sem);
+	down_write_nested(&EXT4_I(inode)->i_data_sem, subclass++);
 	ext4_discard_preallocations(inode);
 
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
@@ -4645,6 +4646,7 @@ int ext4_truncate(struct inode *inode)
 		ext4_ind_truncate(handle, inode);
 
 	up_write(&ei->i_data_sem);
+	subclass--;
 	if (err)
 		goto out_stop;