Optimal method for deleting sub-blocks of a pointer block that do not have on-disk metadata headers for addresses

A non-transitory computer readable medium comprising instructions that are executable in a computer system, wherein the instructions when executed cause the computer system to carry out a method of deleting a first pointer block of a plurality of pointer blocks of a file system from a storage device used by a plurality of applications, wherein the plurality of pointer blocks are each subdivided into sub-blocks, said method comprising:

• determining that a first sub-block of the first pointer block is marked as being empty of any addresses of the file system at which storage space is allocated to files of the applications;
• determining that a second sub-block of the first pointer block has not been marked as being empty;
• in response to the determining that the second sub-block has not been marked as being empty, determining that the second sub-block does not contain any addresses of the file system at which storage space is allocated to the files of the applications;
• and
• in response to the determining that the first sub-block is marked as being empty and the determining that the second sub-block does not contain any addresses of the file system, deleting the first pointer block from the storage device.

A computer system comprising:

• a plurality of hosts in a cluster executing a plurality of applications, and
• a storage system including a storage device and a file system from the storage device used by the plurality of applications, wherein the file system includes a plurality of pointer blocks that are each subdivided into sub-blocks, the storage system being configured to:
• determine that a first sub-block of a first pointer block is marked as being empty of any addresses of the file system at which storage space is allocated to files of the applications,
• determine that a second sub-block of the first pointer block has not been marked as being empty,
• in response to the determining that the second sub-block has not been marked as being empty, determine that the second sub-block does not contain any addresses of the file system at which storage space is allocated to the files of the applications, and
• in response to the determining that the first sub-block is marked as being empty and the determining that the second sub-block does not contain any addresses of the file system, delete the first pointer block from the storage device.