MFC r249194 (by trasz):
Make SYNCHRONIZE CACHE work with LUNs backed by device files (as opposed
to regular files, which already worked fine).  With this change, it's no
longer neccessary to use "ctladm realsync off" workaround.

(cherry picked from commit 4bd7a45db17b657df1b4929c4244148d35e1245b)
MFC 244015:
  ------------------------------------------------------------------------
  r244015 | ken | 2012-12-07 21:16:07 -0700 (Fri, 07 Dec 2012) | 17 lines

  Fix the CTL OOA queue dumping code so that it does not hold a mutex
  while doing a copyout.  That can cause a panic, because copyout
  can trigger VM faults, and we can't handle VM faults while holding
  a mutex.

  The solution here is to malloc a separate buffer to hold the OOA
  queue entries, so that we don't risk a VM fault while filling up
  the buffer and we don't have to drop the lock.  The other solution
  would be to wire the user's memory while filling their buffer with
  copyout, but that would have been a little more complex.

  Also fix a debugging parenthesis issue in ctl_abort_task() pointed
  out by Chuck Tuffli.

  Sponsored by:   Spectra Logic Corporation

(cherry picked from commit d6db3bc7e3edd193173f9063f77ca80337df8543)
MFC r249102 (by trasz):
Since the CTL version in FreeBSD does not support High Availability,
ctl_is_single should always be set to 1.  Make it so.  Previously
it was always 0, because ctl_isc_start() never got to run.

(cherry picked from commit 70702718ec0e97970a6171e2ee00c1eaa2017100)
MFC r249256 (by ken):
Fix a memory leak that showed up when we delete LUNs.  The memory used for
the LUN was never freed.

ctl.c:          Adjust ctl_alloc_lun() to make sure we don't clear the
                CTL_LUN_MALLOCED flag.

(cherry picked from commit 0eee89721d2f463bfe461eba2fdbfb7ee8f98d16)
MFC r250131 (by eadler):
Correct a few sizeof()s

(cherry picked from commit 5c19171c428b7fee04c4c0b5cd10ac3a46adc44e)
MFC r250460 (by eadler):
Fix a bunch of typos.

(cherry picked from commit 6c5fbc74897e65079596e3cfbe3a6f6e5f73c061)
MFC r249065 (by trasz):
Fix locking problem in ctl_maintenance_in() - one cannot use M_WAITOK or call
ctl_done() with mutex held.

(cherry picked from commit 4ed71a60c8a4028d98038d31e4dcf7d71b88f473)
MFC r256533:
Unhide "Serial Number" lines from bootverbose.  That information may
be useful for system administration to have in hard copy (in logs) if
one of several devices suddenly dies.

(cherry picked from commit 91f2b96b201c5c579f6681cb35cbc90d6d079c4a)
MFC r256552:
Unify periph invalidation and destruction reporting.
Print message containing device model and serial number on invalidation.

(cherry picked from commit 690b084ad09c2abcca3ee315fe51ebf288ad36e5)
MFC r229663: Allow to change vfs.zfs.arc_meta_limit at runtime.

- Change vfs.zfs.arc_meta_used from CTLFLAG_RDTUN to CTLFLAG_RD,
as it is not a tunable.

MFC slacker:	pjd
MFC r258294:
Fix ZFS deadlock when sending a snapshot which is mounted.

Approved by:	re (glebius)
Sponsored by:	Multiplay
ZFS/GFS handling fixes