My whole point in posting was based on your reply here. Removing files does not "delete" them. It just removes any references to them. True deletion only occurs when the space is zeroed out, either by securely erasing the file on an HDD or by running trim on an SSD. Until that occurs, the file is not deleted, just not referenced.

No - deletion is when the blocks allocated to the file are released for reuse, including the inode.

Secure delete is sloooow, and for large files can take hours. And unless the filesystem supports doing secure delete, you NEVER get access to the metadata for the file. You can google for "object reuse" as that is what your "secure delete" is a part of.

No filesystem support does secure delete because it is too slow. The SSD trim is an internal one due to the data blocks present MUST be zeroed before a write can be done - otherwise the data is corrupted (you don't write 0s... only 1s). Thus the SSD has its own "filesystem" that handles relocation (zeroing data is very slow) for a given block. Thus the SSD has to track block numbers via indirection while zeroing other blocks. It also means you don't get access to the entire storage as some percentage is always set aside for failed writes/zeroing, and for blocks that can be written to.