Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

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

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

Replace kernel virtual address space allocation with vmem. This provides
transparent layering and better fragmentation.

- Normalize functions that allocate memory to use kmem_*
- Those that allocate address space are named kva_*
- Those that operate on maps are named kmap_*
- Implement recursive allocation handling for kmem_arena in vmem.

Reviewed by: alc
Tested by: pho
Sponsored by: EMC / Isilon Storage Division

Finally... Import the latest open-source ZFS version - (SPA) 28.

Few new things available from now on:

- Data deduplication.
- Triple parity RAIDZ (RAIDZ3).
- zfs diff.
- zpool split.
- Snapshot holds.
- zpool import -F. Allows to rewind corrupted pool to earlier
transaction group.
- Possibility to import pool in read-only mode.

MFC after: 1 month

opensolaris_kmem kmem_size(): report lesser of vm_kmem_size and available
physical memory

This is needed to correctly autotune ZFS ARC size when vm_kmem_size is
set to value larger than available physical memory.

MFC after: 2 weeks

Update ZFS from version 6 to 13 and bring some FreeBSD-specific changes.

This bring huge amount of changes, I'll enumerate only user-visible changes:

- Delegated Administration

Allows regular users to perform ZFS operations, like file system
creation, snapshot creation, etc.

- L2ARC

Level 2 cache for ZFS - allows to use additional disks for cache.
Huge performance improvements mostly for random read of mostly
static content.

- slog

Allow to use additional disks for ZFS Intent Log to speed up
operations like fsync(2).

- vfs.zfs.super_owner

Allows regular users to perform privileged operations on files stored
on ZFS file systems owned by him. Very careful with this one.

- chflags(2)

Not all the flags are supported. This still needs work.

- ZFSBoot

Support to boot off of ZFS pool. Not finished, AFAIK.

Submitted by: dfr

- Snapshot properties

- New failure modes

Before if write requested failed, system paniced. Now one
can select from one of three failure modes:
- panic - panic on write error
- wait - wait for disk to reappear
- continue - serve read requests if possible, block write requests

- Refquota, refreservation properties

Just quota and reservation properties, but don't count space consumed
by children file systems, clones and snapshots.

- Sparse volumes

ZVOLs that don't reserve space in the pool.

- External attributes

Compatible with extattr(2).

- NFSv4-ACLs

Not sure about the status, might not be complete yet.

Submitted by: trasz

- Creation-time properties

- Regression tests for zpool(8) command.

Obtained from: OpenSolaris

Remove definition of KMEM_DEBUG accidentally brought in by latest DTrace
import.

Noticed by: thompsa

Merge latest DTrace changes from Perforce.

Remove redundant redeclaration of 'zone_drain'.

Forced commit to note that these files were repo copied.

Change type of kmem_used() and kmem_size() functions to uint64_t, so it
doesn't overflow in arc.c in this check:

if (kmem_used() > (kmem_size() * 4) / 5)
return (1);

With this bug ZFS almost doesn't cache.

Only 32bit machines are affected that have vm.kmem_size set to values >=1GB.

Reported by: David Taylor <davidt@yadt.co.uk>

Try to stabilize ZFS with regard to memory consumption:
- Allow to shrink ARC down to 16MB (instead of 64MB).
- Set arc_max to 1/2 of kmem_map by default.
- Start freeing things earlier when low memory situation is detected.
- Serialize execution of arc_lowmem().

I decided to setup minimum ZFS memory requirements to 512MB of RAM and 256MB of
kmem_map size. If there is less RAM or kmem_map, a warning will be printed.
World is cruel, be no better. In other words: modern file system requires
modern hardware:)

From ZFS administration guide:

"Currently the minimum amount of memory recommended to install a Solaris
system is 512 Mbytes. However, for good ZFS performance, at least one
Gbyte or more of memory is recommended."

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/)