The vfs.hammer.* sysctl's that lack a description are as follows:

vfs.hammer.fsync_mode:

vfs.hammer.yield_check:
vfs.hammer.write_mode:
vfs.hammer.verify_data:
vfs.hammer.verify_zone:
vfs.hammer.autoflush:
vfs.hammer.contention_count:
vfs.hammer.zone_limit:
vfs.hammer.count_io_running_write:
vfs.hammer.count_io_locked:
vfs.hammer.count_io_running_read:
vfs.hammer.count_reservations:
vfs.hammer.count_refedbufs:
vfs.hammer.count_dirtybufspace:
vfs.hammer.stats_redo:
vfs.hammer.stats_undo:
vfs.hammer.stats_commits:
vfs.hammer.stats_inode_flushes:
vfs.hammer.stats_disk_write:
vfs.hammer.stats_disk_read:
vfs.hammer.stats_file_iopsw:
vfs.hammer.stats_file_iopsr:
vfs.hammer.stats_file_write:
vfs.hammer.stats_file_read:
vfs.hammer.stats_record_iterations:
vfs.hammer.stats_btree_root_iterations:
vfs.hammer.stats_btree_iterations:
vfs.hammer.stats_btree_splits:
vfs.hammer.stats_btree_elements:
vfs.hammer.stats_btree_deletes:
vfs.hammer.stats_btree_inserts:
vfs.hammer.stats_btree_lookups:
vfs.hammer.stats_btree_searches:
vfs.hammer.count_extra_space_used:
vfs.hammer.count_nodes:
vfs.hammer.count_buffers:
vfs.hammer.count_volumes:
vfs.hammer.count_record_datas:
vfs.hammer.count_records:
vfs.hammer.count_reclaiming:
vfs.hammer.count_iqueued:
vfs.hammer.count_inodes:
vfs.hammer.count_fsyncs:
vfs.hammer.limit_redo:
vfs.hammer.limit_reclaim:
vfs.hammer.limit_inode_recs:
vfs.hammer.limit_recs:
vfs.hammer.limit_running_io:
vfs.hammer.limit_dirtybufspace:
vfs.hammer.cluster_enable:
vfs.hammer.debug_critical:
vfs.hammer.debug_recover_faults:
vfs.hammer.debug_recover:
vfs.hammer.debug_tid:
vfs.hammer.debug_btree:
vfs.hammer.debug_locks:
vfs.hammer.debug_inode:
vfs.hammer.debug_debug:
vfs.hammer.debug_io:
vfs.hammer.debug_general:
vfs.hammer.supported_version:

Research these sysctl's in the kernel code and document each with a descriptive but concise sentence (approximately 3-15 words).

Deliverables: A description of each sysctl listed above.

Bonus deliverables: The above descriptions in the form of a kernel patch