Question

Is there any hdfs dfs command to restrict number of files to be created in a directory

Answer 1

Not sure about the command but you can set this property in the hdfs-default.xml file as follows.

<property>
  <name>dfs.namenode.fs-limits.max-directory-items</name>
  <value>1048576</value>
  <description>Defines the maximum number of items that a directory may
      contain. Cannot set the property to a value less than 1 or more than
      6400000.</description>
</property>