Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC 248571,248976,249004,249042,249188,249195-249196,249206,249207,249319,
249326,249356-249357

Merge libzfs_core and other ZFS bugfixes and improvements.

MFC r248571:
MFV 238590, 238592:
In the first zfs ioctl restructuring phase, the libzfs_core library was
introduced. It is a new thin library that wraps around kernel ioctl's.
The idea is to provide a forward-compatible way of dealing with new
features. Arguments are passed in nvlists and not random zfs_cmd fields,
new-style ioctls are logged to pool history using a new method of
history logging.

http://blog.delphix.com/matt/2012/01/17/the-future-of-libzfs/

MFV 247580 [1]:
To address issues of several deadlocks and race conditions the locking
code around dsl_dataset was rewritten and the interface to synctasks
was changed.

User-Visible Changes:
"zfs snapshot" can create more arbitrary snapshots at once (atomically)
"zfs destroy" destroys multiple snapshots at once
"zfs recv" has improved performance

Backward Compatibility:
I have extended the compatibility layer to support full backward
compatibility by remapping or rewriting the responsible ioctl arguments.
Old utilities are fully supported by the new kernel module.

Forward Compatibility:
New utilities work with old kernels with the following restrictions:
- creating, destroying, holding and releasing of multiple snapshots
at once is not supported, this includes recursive (-r) commands

Illumos ZFS issues:
2882 implement libzfs_core
2900 "zfs snapshot" should be able to create multiple,
arbitrary snapshots at once
3464 zfs synctask code needs restructuring

MFC r248976:
Call dmu_snapshot_list_next() in zvol.c with dsl_pool_config lock held

MFC r249004:
Do not check against uninitialized rc and comment out vendor code

MFC r249042:
Fix possible pool hold leak in dmu_send_impl()

Illumos ZFS issues:
3645 dmu_send_impl: possibilty of pool hold leak

MFC r249188:
Import vendor change to reduce diff, no effect on FreeBSD.

Illumos ZFS issues:
3517 importing pool with autoreplace=on and "hole" vdevs crashes
syseventd

MFC r249195:
Merge change from vendor to reduce diff only.
ZFS dtrace probes are not supported on FreeBSD yet.

Illumos ZFS issues:
3598 want to dtrace when errors are generated in zfs

MFC r249196:
Provide a fix for kernel panic if receiving recursive deduplicated
streams. Problem reported to vendor.

Illumos ZFS issues:
3692 Panic on zfs receive of a recursive deduplicated stream

MFC r249206:
Merge vendor change - modify time processing in deadman thread.

Illumos ZFS issues:
3618 ::zio dcmd does not show timestamp data

MFC r249207:
Allow zdb to output a histogram of compressed block sizes.

Illumos ZFS issues:
3641 want a histogram of compressed block sizes

MFC r249319:
ZFS expects a copyout of zfs_cmd_t on an ioctl error. Our sys_ioctl()
doesn't copyout in this case.

To solve this a new struct zfs_iocparm_t is introduced consisting of:
- zfs_ioctl_version (future backwards compatibility purposes)
- user space pointer to zfs_cmd_t (copyin and copyout)
- size of zfs_cmd_t (verification purposes)

The copyin and copyout of zfs_cmd_t is now done the illumos (vendor) way
what makes porting of new changes easier and ensures correct behavior if
returning an error.

MFC r249326:
Cast (void *)(uintptr_t) on copyout and copyin of zfs_iocparm_t.zfs_cmd

MFC r249356:
Merge bugfixes accepted and integrated by vendor. Underlying problems
have been reported by us and fixed in r240942 and r249196.

Illumos ZFS issues:
3645 dmu_send_impl: possibilty of pool hold leak
3692 Panic on zfs receive of a recursive deduplicated stream

MFC r249357:
Fix libzfs to report error instead of returning zero if trying to hold or
release a non-existing snapshot of a existing dataset. In recursive case
error is reported if no snapshots with the requested name have been found.

Illumos ZFS issues:
3699 zfs hold or release of a non-existent snapshot does not output
error

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Use double quotes when checking the value of MACHINE_ARCH.

Sponsored by: The FreeBSD Foundation

The DTrace instrumentation object is going to be i386/amd64 only.

Sponsored by: The FreeBSD Foundation

libdtrace, dtrace(1) and lockstat(1) are for i386 and amd64 only right
now.

Sponsored by: The FreeBSD Foundation

Add the DTrace libraries and D library scripts.

Remove options MK_LIBKSE and DEFAULT_THREAD_LIB now that we no longer
build libkse. This should fix WITHOUT_LIBTHR builds as a side effect.

Tweak the handling of "WITHOUT_LIBPTHREAD". Also remove the accidental
treatment of 'LIBKSE' as an "old style" knob.

Submitted by: ru
Approved by: re(kensmith)

Repo copy libpthreads to libkse.
This introduces the WITHOUT_LIBKSE nob,
and changes WITHOUT_LIBPTHREADS to mean with neither threading libs.
Approved by: re(kensmith)

Don't build bits that depend on the pthreads support if a
system was configured without such support.

Approved by: re (kensmith)

- Reduce number of atomic operations needed to be implemented in asm by
implementing some of them using existing ones.
- Allow to compile ZFS on all archs and use atomic operations surrounded
by global mutex on archs we don't have or can't have all atomic
operations needed by ZFS.

Apply a set of style.Makefile(5) changes to src/cddl/ makefiles.
There are some insignificant non-style changes as well.

Not fixed: makefiles use ${LIBTHR} that doesn't exist, thus
breaking "make checkdpadd" and not tracking dependencies
properly.

Approved by: pjd

Build ZFS on amd64 and pc98.

Approved by: pjd@

Please welcome ZFS - The last word in file systems.

ZFS file system was ported from OpenSolaris operating system. The code in under
CDDL license.

I'd like to thank all SUN developers that created this great piece of software.

Supported by: Wheel LTD (http://www.wheel.pl/)
Supported by: The FreeBSD Foundation (http://www.freebsdfoundation.org/)
Supported by: Sentex (http://www.sentex.net/)