Abstract: A method, system and computer program product for the defragmentation of a file system with little or no free space. Defragmenting file fragments in a memory file system comprises determining a defragmentation sequence for re-ordering fragments of files in the file system; determining if at least one fragment in the file system is moved more than once in the defragmentation sequence; removing the at least one fragment from the file system if it is moved more than once in the sequence; determining the defragmentation sequence without considering the at least one removed file fragment; rearranging the remaining file fragments on the file system according to the determined defragmentation sequence; and replacing the removed file fragments in the file system after the defragmentation.