4.3.2. Directories (S

4.3.2. Directories (S_IFDIR)

The data fork contains the directory's entries and associated data. The format of the entries is also determined by the di_format value and can be one of 3 formats:

XFS_DINODE_FMT_LOCAL: The directory entries are fully contained within the inode. This is accessed by casting the value from XFS_DFORK_DPTR to xfs_dir2_sf_t*.
XFS_DINODE_FMT_EXTENTS: The actual directory entries are located in another filesystem block, the inode contains an array of extents to these filesystem blocks (xfs_bmbt_rec_t*).
XFS_DINODE_FMT_BTREE: The directory entries are contained in the leaves of a B+tree. The inode contains the root node (xfs_bmdr_block_t*).

Details for each of these directory formats are covered in the Directories section (Chapter 6, Directories) later on.