+Normally, ext4 allows an inode to have no more than 65,000 hard links.
+This applies to regular files as well as directories, which means that
+there can be no more than 64,998 subdirectories in a directory (because
+each of the '.' and '..' entries, as well as the directory entry for the
+directory in its parent directory counts as a hard link). This feature
+lifts this limit by causing ext4 to use a link count of 1 to indicate
+that the number of hard links to a directory is not known when the link
+count might exceed the maximum count limit.
+.TP
+.B ea_inode
+.br
+Normally, a file's extended attributes and associated metadata must fit within
+the inode or the inode's associated extended attribute block. This feature
+allows the value of each extended attribute to be placed in the data blocks of a
+separate inode if necessary, increasing the limit on the size and number of
+extended attributes per file.
+.TP
+.B encrypt
+.br
+Enables support for file-system level encryption of data blocks and file
+names. The inode metadata (timestamps, file size, user/group ownership,
+etc.) is
+.I not
+encrypted.
+.IP
+This feature is most useful on file systems with multiple users, or
+where not all files should be encrypted. In many use cases, especially
+on single-user systems, encryption at the block device layer using
+dm-crypt may provide much better security.
+.TP
+.B ext_attr
+.br
+This feature enables the use of extended attributes. This feature is
+supported by ext2, ext3, and ext4.