systems were repo-copied from sys/miscfs to sys/fs.

- Renamed the following file systems and their modules:
  fdesc -> fdescfs, portal -> portalfs, union -> unionfs.

- Renamed corresponding kernel options:
  FDESC -> FDESCFS, PORTAL -> PORTALFS, UNION -> UNIONFS.

- Install header files for the above file systems.

- Removed bogus -I${.CURDIR}/../../sys CFLAGS from userland
  Makefiles.

the number of references on the filesystem root vnode to be both
expected and released. Many filesystems hold an extra reference on
the filesystem root vnode, which must be accounted for when
determining if the filesystem is busy and then released if it isn't
busy. The old `skipvp' approach required individual filesystem
xxx_unmount functions to re-implement much of vflush()'s logic to
deal with the root vnode.

All 9 filesystems that hold an extra reference on the root vnode
got the logic wrong in the case of forced unmounts, so `umount -f'
would always fail if there were any extra root vnode references.
Fix this issue centrally in vflush(), now that we can.

This commit also fixes a vnode reference leak in devfs, which could
result in idle devfs filesystems that refuse to unmount.

Reviewed by:	phk, bp

other "system" header files.

Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.

Sort sys/*.h includes where possible in affected files.

OK'ed by:	bde (with reservations)

  introduce a new argument, "namespace", rather than relying on a first-
  character namespace indicator.  This is in line with more recent
  thinking on EA interfaces on various mailing lists, including the
  posix1e, Linux acl-devel, and trustedbsd-discuss forums.  Two namespaces
  are defined by default, EXTATTR_NAMESPACE_SYSTEM and
  EXTATTR_NAMESPACE_USER, where the primary distinction lies in the
  access control model: user EAs are accessible based on the normal
  MAC and DAC file/directory protections, and system attributes are
  limited to kernel-originated or appropriately privileged userland
  requests.

o These API changes occur at several levels: the namespace argument is
  introduced in the extattr_{get,set}_file() system call interfaces,
  at the vnode operation level in the vop_{get,set}extattr() interfaces,
  and in the UFS extended attribute implementation.  Changes are also
  introduced in the VFS extattrctl() interface (system call, VFS,
  and UFS implementation), where the arguments are modified to include
  a namespace field, as well as modified to advoid direct access to
  userspace variables from below the VFS layer (in the style of recent
  changes to mount by adrian@FreeBSD.org).  This required some cleanup
  and bug fixing regarding VFS locks and the VFS interface, as a vnode
  pointer may now be optionally submitted to the VFS_EXTATTRCTL()
  call.  Updated documentation for the VFS interface will be committed
  shortly.

o In the near future, the auto-starting feature will be updated to
  search two sub-directories to the ".attribute" directory in appropriate
  file systems: "user" and "system" to locate attributes intended for
  those namespaces, as the single filename is no longer sufficient
  to indicate what namespace the attribute is intended for.  Until this
  is committed, all attributes auto-started by UFS will be placed in
  the EXTATTR_NAMESPACE_SYSTEM namespace.

o The default POSIX.1e attribute names for ACLs and Capabilities have
  been updated to no longer include the '$' in their filename.  As such,
  if you're using these features, you'll need to rename the attribute
  backing files to the same names without '$' symbols in front.

o Note that these changes will require changes in userland, which will
  be committed shortly.  These include modifications to the extended
  attribute utilities, as well as to libutil for new namespace
  string conversion routines.  Once the matching userland changes are
  committed, a buildworld is recommended to update all the necessary
  include files and verify that the kernel and userland environments
  are in sync.  Note: If you do not use extended attributes (most people
  won't), upgrading is not imperative although since the system call
  API has changed, the new userland extended attribute code will no longer
  compile with old include files.

o Couple of minor cleanups while I'm there: make more code compilation
  conditional on FFS_EXTATTR, which should recover a bit of space on
  kernels running without EA's, as well as update copyright dates.

Obtained from:	TrustedBSD Project

An initial tidyup of the mount() syscall and VFS mount code.

This code replaces the earlier work done by jlemon in an attempt to
make linux_mount() work.

* the guts of the mount work has been moved into vfs_mount().

* move `type', `path' and `flags' from being userland variables into being
  kernel variables in vfs_mount(). `data' remains a pointer into
  userspace.

* Attempt to verify the `type' and `path' strings passed to vfs_mount()
  aren't too long.

* rework mount() and linux_mount() to take the userland parameters
  (besides data, as mentioned) and pass kernel variables to vfs_mount().
  (linux_mount() already did this, I've just tidied it up a little more.)

* remove the copyin*() stuff for `path'. `data' still requires copyin*()
  since its a pointer into userland.

* set `mount->mnt_statf_mntonname' in vfs_mount() rather than in each
  filesystem.  This variable is generally initialised with `path', and
  each filesystem can override it if they want to.

* NOTE: f_mntonname is intiailised with "/" in the case of a root mount.

mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

similarily, for releasing a lock, we now have:

mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.

The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.

Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:

MTX_QUIET and MTX_NOSWITCH

The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:

mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.

Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.

Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.

Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.

Finally, caught up to the interface changes in all sys code.

Contributors: jake, jhb, jasone (in no particular order)

fondling implementation details.

Created with: sed(1)
Reviewed by: md5(1)