Providing unique inodes across multiple file system namespaces

A computer program product for storage management in an aggregated file system, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to:

• track, by the processor, assigned inodes, inodes currently used by applications and a rate of inode requests for sub-file systems of the aggregated file system, wherein any sub-file system in a first aggregated file system environment is configurable as a top-file system portion of a second aggregated file system environment;
• receive, by the processor, a request for a unique range of inode numbers in the aggregated file system, wherein the request for the unique range of inode numbers is made from a top-file system portion or individual sub-file systems of the aggregated file system, each sub-file system of the aggregated file system consumes a flexible range of inode numbers, and a namespace in the top file system portion of the aggregation file system and pointers to the sub-file systems include a name of a directory in a particular sub-file system that is its inode number in the top file system portion;
• provide, by the processor, the unique range of inode numbers to sub-file systems of the aggregated file system while providing that each sub-file system of the aggregated file system has a required, flexible and unique range of inode numbers and that no two sub-file systems have overlapping inode numbers;
• determine, by the processor, that a particular sub-file system requires more inode numbers;
• revoke, by the processor, one or more inode numbers from one or more other sub-file systems;
• and
• allocate, by the processor, the revoked inode numbers to the particular sub-file system.

An apparatus comprising:

• a memory storing instructions;
• and
• one or more processors executing the instructions to:
• track assigned inodes, inodes currently used by applications and a rate of inode requests-for sub-file systems of the aggregated file system, wherein any sub-file system in a first aggregated file system environment is configurable as a top-file system portion of a second aggregated file system environment;
• receive a request for a unique range of inode numbers in the aggregated file system, wherein the request for the unique range of inode numbers is made from a top-file system portion or individual sub-file systems of the aggregated file system, each sub-file system of the aggregated file system consumes a flexible range of inode numbers, and a namespace in the top file system portion of the aggregation file system and pointers to the sub-file systems include a name of a directory in a particular sub-file system that is its inode number in the top file system portion;
• provide the unique range of inode numbers to sub-file systems of the aggregated file system while providing that each sub-file system of the aggregated file system has a required, flexible and unique range of inode numbers and that no two sub-file systems have overlapping inode numbers;
• determine that a particular sub-file system requires more inode numbers;
• revoke one or more inode numbers from one or more other sub-file systems;
• and
• allocate the revoked inode numbers to the particular sub-file system.