the problem of mounting a writeable partition

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dear all 
	I have problems about mounting a writeable partition.
	when I create a partition which capacity is larger than 2MB and
        mount it with JFFS2 filesystem , it works well .
        But when I create a partition which capacity is smaller than 2MB
        and mount it , I can't create any file on it.
	I try to make a  directory on it , it displays the following error
        message :
	
	mkdir: Cannot create directory `test': No space left on device
	
	Is there any limitation about the partition size.
	
	Any help would be appreciated.