Making Changes Persistent

Until now, when we unmounted our file-system, we lost all entires we created (well, not all - when we wrote into buffer-heads, they got written into disk - which is why we got some funny entries in directories, after un-mounting and re-mounting a file system on which we created directories).

We need to have the following:

• Write the super-block to disk (already done).
• Write new or updated inodes to disk.
• Delete inodes from disk when their files (actually directories) are erased.
• Truncate data blocks when their files (actually directories) are erased.

Originally written by guy keren