rc.d/sysctl: Fix error messages about unknown OIDs.

There are three situations where the sysctl script is called:
1. "start", very early
2. "lastload", near the end of rc
3. "reload", at admin request while the system is booted

Ignore unknown OIDs in situation 1 because kernel modules may not be loaded
yet and complain about them in situations 2 and 3.

PR:		conf/174595
Submitted by:	Olivier Smedts
Remove __FreeBSD_version ifdefs.
The purpose of this change to the FFS layout policy is to reduce the
running time for a full fsck. It also reduces the random access time
for large files and speeds the traversal time for directory tree walks.

The key idea is to reserve a small area in each cylinder group
immediately following the inode blocks for the use of metadata,
specifically indirect blocks and directory contents. The new policy
is to preferentially place metadata in the metadata area and
everything else in the blocks that follow the metadata area.

The size of this area can be set when creating a filesystem using
newfs(8) or changed in an existing filesystem using tunefs(8).
Both utilities use the `-k held-for-metadata-blocks' option to
specify the amount of space to be held for metadata blocks in each
cylinder group. By default, newfs(8) sets this area to half of
minfree (typically 4% of the data area).

This work was inspired by a paper presented at Usenix's FAST '13:
www.usenix.org/conference/fast13/ffsck-fast-file-system-checker

Details of this implementation appears in the April 2013 of ;login:
www.usenix.org/publications/login/april-2013-volume-38-number-2.
A copy of the April 2013 ;login: paper can also be downloaded
from: www.mckusick.com/publications/faster_fsck.pdf.

Reviewed by: kib
Tested by:   Peter Holm
MFC after:   4 weeks
As it's done for libstdc++, use SJLJ-based exceptions on arm when we're not
using EABI, and use unwind-arm.h instead of unwind-generic.h when using EABI.
Speed up fsck by caching the cylinder group maps in pass1 so
that they do not need to be read again in pass5. As this nearly
doubles the memory requirement for fsck, the cache is thrown away
if other memory needs in fsck would otherwise fail. Thus, the
memory footprint of fsck remains unchanged in memory constrained
environments.

This work was inspired by a paper presented at Usenix's FAST '13:
www.usenix.org/conference/fast13/ffsck-fast-file-system-checker

Details of this implementation appears in the April 2013 of ;login:
www.usenix.org/publications/login/april-2013-volume-38-number-2.
A copy of the April 2013 ;login: paper can also be downloaded
from: www.mckusick.com/publications/faster_fsck.pdf.

Reviewed by: kib
Tested by:   Peter Holm
MFC after:   4 weeks
Don't attempt to reference sc before testing whether it's NULL.

Submitted by:	Sascha Wildner
Obtained from:	DragonFly
MFC after:	2 weeks
Add AR9300 descriptor decoding.
Revert svn r248625

Clang errors around printf could be trivially fixed, but the breakage in
sbin/fsdb were to significant for this type of change.

Submitter of this changeset has been notified and hopefully this can be
restored soon.
Fix the build after addition of cylinder group cacheing (r248625)

Reported by:   Glen Barber (gjb@)
Pointy hat to: Kirk McKusick (mckusick@)
fbt_typoff_init: fix an off by one in determining required memory size

This issue would be silent most of the time, but if the requested memory
is a multiple of a page size, then accessing one element beyond the end
would lead to a kernel page fault.
Otherwise, the unlucky last type would just be inaccessible.

Reported by:	glebius
Tested by:	glebius
MFC after:	6 days
libdwarf: anonymous types are expected to have empty type names...

or no type attributes at all.
This is according to DWARF specification.

MFC after:	13 days
fbt_getargdesc: correctly handle types for return probes

MFC after:	6 days
Revert r248639 to fix build failure on head/
dtrace: ensure that we can always catch a process (e.g. when -c is used)

It is not guaranteed that a program has a symbol table entry for main
and thus that it would be possible to set a breakpoint on it.

Reviewed by:	rpaulo
Discussed with:	rpaulo
MFC after:	13 days
post mountroot event after a real/final root is mounted

not every time an intermediate root (including the first devfs) is
mounted.
This is also consistent with waking up via root_mount_complete.

Reviewed by:	jhb
MFC after:	13 days
Make `systat -vmstat` to use suffixes to display big floating point numbers
that are not fitting into the specified field width, same as done for ints.
In particular that allows to properly display disk tps above 100k, that are
reachable with modern SSDs.
Revert r247892 now that this has been fixed upstream.
Extend taskqueue(9) to enable per-taskqueue callbacks.

The scope of these callbacks is primarily to support actions that affect the
taskqueue's thread environments.  They are entirely optional, and
consequently are introduced as a new API: taskqueue_set_callback().

This interface allows the caller to specify that a taskqueue requires a
callback and optional context pointer for a given callback type.

The callback types included in this commit can be used to register a
constructor and destructor for thread-local storage using osd(9).  This
allows a particular taskqueue to define that its threads require a specific
type of TLS, without the need for a specially-orchestrated task-based
mechanism for startup and shutdown in order to accomplish it.

Two callback types are supported at this point:

- TASKQUEUE_CALLBACK_TYPE_INIT, called by every thread when it starts, prior
  to processing any tasks.
- TASKQUEUE_CALLBACK_TYPE_SHUTDOWN, called by every thread when it exits,
  after it has processed its last task but before the taskqueue is
  reclaimed.

While I'm here:

- Add two new macros, TQ_ASSERT_LOCKED and TQ_ASSERT_UNLOCKED, and use them
  in appropriate locations.
- Fix taskqueue.9 to mention taskqueue_start_threads(), which is a required
  interface for all consumers of taskqueue(9).

Reviewed by:	kib (all), eadler (taskqueue.9), brd (taskqueue.9)
Approved by:	ken (mentor)
Sponsored by:	Spectra Logic
MFC after:	1 month
ZFS: Fix a panic while unmounting a busy filesystem.

This particular scenario was easily reproduced using a NFS export.  When the
first 'zfs unmount' occurred, it returned EBUSY via this path, while
vflush() had flushed references on the filesystem's root vnode, which in
turn caused its v_interlock to be destroyed.  The next time 'zfs unmount'
was called, vflush() tried to obtain this lock, which caused this panic.

Since vflush() on FreeBSD is a definitive call, there is no need to check
vfsp->vfs_count after it completes.  Simply #ifdef sun this check.

Submitted by:	avg
Reviewed by:	avg
Approved by:	ken (mentor)
MFC after:	1 month
Be more explicit about what each bio_cmd & bio_flags value means.

Reviewed by:	ken (mentor)