Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Until now, smbfs_fullpath() computed the full path starting from the
vnode and following back the chain of n_parent pointers up to the root,
without acquiring the locks of the n_parent vnodes analyzed during the
computation. This is immediately wrong because if the vnode lock is not
held there's no guarantee on the validity of the vnode pointer or the data.
In order to fix, store the whole path in the smbnode structure so that
smbfs_fullpath() can use this information.

Discussed with: kib
Reported and tested by: pho
Sponsored by: iXsystems inc.

- Do not put in the mntqueue half-constructed vnodes.
- Change the code so that it relies on vfs_hash rather than on a
home-made hashtable.
- There's no need to inline fnv_32_buf().

Reviewed by: delphij
Tested by: pho
Sponsored by: iXsystems inc.

Switch to our preferred 2-clause BSD license.

Approved by: bp

Move the head of byte-level advisory lock list from the
filesystem-specific vnode data to the struct vnode. Provide the
default implementation for the vop_advlock and vop_advlockasync.
Purge the locks on the vnode reclaim by using the lf_purgelocks().
The default implementation is augmented for the nfs and smbfs.
In the nfs_advlock, push the Giant inside the nfs_dolock.

Before the change, the vop_advlock and vop_advlockasync have taken the
unlocked vnode and dereferenced the fs-private inode data, racing with
with the vnode reclamation due to forced unmount. Now, the vop_getattr
under the shared vnode lock is used to obtain the inode size, and
later, in the lf_advlockasync, after locking the vnode interlock, the
VI_DOOMED flag is checked to prevent an operation on the doomed vnode.

The implementation of the lf_purgelocks() is submitted by dfr.

Reported by: kris
Tested by: kris, pho
Discussed with: jeff, dfr
MFC after: 2 weeks

/* -> /*- for copyright notices, minor format tweaks as necessary

Fixes problems that occurred when a file was removed and a directory
created with the same name, and vice versa:
- Immediately recycle vnodes of files & directories that have been deleted
or renamed.
- When looking an entry in the VFS name cache or smbfs's private
cache, make sure the vnode type is consistent with the type of file
the server thinks it is, and re-create the vnode if it isn't.

The alternative to this is to recycle vnodes unconditionally when their
use count drops to 0, but this would make all the caching we do
mostly useless.

PR: 62342
MFC after: 2 weeks

Send the close request to the SMB server in smbfs_inactive(), instead of
smbfs_close(). This fixes paging to and from mmap()'d regions of smbfs
files after the descriptor has been closed, and makes thttpd, GNU ld,
and perhaps more things work that depend on being able to do this.

PR: 48291

Remove fragments of support for the FreeBSD 3.x and 4.x branches.

Store a reference to the parent directory's vnode in struct smbnode,
not to the parent's smbnode, which may be freed during the lifetime
of the child if the mount is forcibly unmounted. umount -f should now
work properly (ie. not panic) on smbfs mounts.

Implement additional SMB calls to allow proper update of file size as some
file servers fail to do it in the right way.

New NFLUSHWIRE flag marks pending flush request(s).

NB: not all cases covered by this commit.

Obtained from: Darwin

Import kernel part of SMB/CIFS requester.
Add smbfs(CIFS) filesystem.

Userland part will be in the ports tree for a while.

Obtained from: smbfs-1.3.7-dev package.