The Base Operating System constants and control block structure definitions are contained in header files in the /usr/include and /usr/include/sys directories. For a list of the major constants and control blocks and their corresponding header files, see "List of Major Control Block Header Files"
The File Systems Overview for System Management explains types and command characteristics of file systems.
Files, Directories, and File Systems for Programmers gives an overiew and orientation to the journaled file system (JFS).
Programming in the Kernel Environment Overview.
Virtual File System Overview.
Logical Volume Programming Overview.