Update drive database

Add Corsair Force GS drive (obtained from drive_id)
Add Kingston HyperX 3K (obtained from drive_id)
Add OCZ Vertex 4 drive (obtained from drive_id)
Add Samsung SM843T enterprise drive (obtained from drive_id)
Add entries for additional sizes of Intel 320/330/335/520 series
Add Cruical C400 (obtained from Illumos user's sd.conf)
Add Toshiba SSD (obtained from Illumos user's sd.conf)
Add Samsung's first SLC SSD (obtained from drive_id)
Add OCZ Core Series (obtained from drive_id)
Add Intel DC S3700 (obtained from drive_id)

Notes:

1. The drive identifer obtained for the Samsung SM843T was MZ7WD480. The
rest were extrapolated. The additional entries were checked with Google
to verify that such drives exist in the wild.

2. The additional entries for Intel drives were extrapolated from
existing entries. The additional entries were checked with Google to
verify that such drives exist in the wild.

3. The "ATA     C400-MTFDDAC512M" and "ATA     TOSHIBA THNSNH51" entries
are from the sd.conf of gcbirzan on freenode. Additional entries were
extrapolated from them and checked with Google.

4. I obtained the Samsung MCCOE64G entry from an actual drive. The
Samsung MCCOE32G entry was extrapolated from it and checked with
Google.

5. I obtained the SSDSC2BA10 from a 100GB Intel DC S3700 drive and
extrapolated the entries for the additional models.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1752
Fix memory leak false positive in log_internal()

When building the spl with --enable-debug-kmem-tracking a memory
leak is detected in log_internal().  This happens to be a false
positive because the memory was freed using strfree() instead of
kmem_free().  All kmem_alloc()'s must be released with kmem_free()
to ensure correct accounting.

  SPL: kmem leaked 135/5641311 bytes
  address          size  data             func:line
  ffff8800cba7cd80 135   ZZZZZZZZZZZZZZZZ log_internal:456

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Export symbols dsl_pool_config_{enter,exit}

These are needed by consumers (i.e. Lustre) who wish to use the
dsl_prop_register() interface to register callbacks when pool
properties of interest change.  This interface requires that the
DSL pool configuration lock is held when called.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1762
Update detach section of zpool(8)

The detach section of the zpool(8) man page now suggests the
offline command.  Using offline may be more appropriate for
certain situations.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1776
Fix libblkid support

libblkid support is dormant because the autotools check is broken and
liblkid identifies ZFS vdevs as "zfs_member", not "zfs". We fix that
with a few changes:

First, we fix the libblkid autotools check to do a few things:

1. Make a 64MB file, which is the minimum size ZFS permits.
2. Make 4 fake uberblock entries to make libblkid's check succeed.
3. Return 0 upon success to make autotools use the success case.
4. Include stdlib.h to avoid implicit declration of free().
5. Check for "zfs_member", not "zfs"
6. Make --with-blkid disable autotools check (avoids Gentoo sandbox violation)
7. Pass '-lblkid' correctly using LIBS not LDFLAGS.

Second, we change the libblkid support to scan for "zfs_member", not
"zfs".

This makes --with-blkid work on Gentoo.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1751
Generate libraries with correct DT_NEEDED entries

Libraries that depend on other libraries should list them in ELF's
DT_NEEDED field so that programs linking to them do not need to specify
those libraries unless they depend on them as well. This is not the case
in the current code and the consequence is that anything that needs a
library must know its dependencies. This is fragile and caused GRUB2's
configure script to break when a dependency was added on libblkid in
libzfs.

This resolves that problem by using LIBADD/LDADD to specify libraries in
Makefile.am instead of LDFLAGS. This ensures that proper DT_NEEDED
entries are generated and prevents GRUB2's configure script from
breaking in the presence of a libblkid dependency. This also removes
unneeded dependencies from various files.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1751
Fix libzfs_core changes to follow GNU libtool guidelines

The GNU libtool documentation states to start with a version of 0:0:0,
rather than 1:1:0. Illumos uses the name libzfs_core.so.1, so to be
consistent, we should go with 1:0:0.

http://www.gnu.org/software/libtool/manual/libtool.html#Updating-version-info

The GNU libtool documentation also provides guidence on how the version
information should be incremented. Doing this does a SONAME bump of the
libzfs and libzpool libraries. This is particularly important on Gentoo
because a SONAME bump enables portage to retain the older libraries
until any packages that link to them are rebuilt. The main example of
this is GRUB2's grub2-mkconfig, which will break unless it is rebuilt
against the new libraries.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1751
Illumos #3552

3552 condensing one space map burns 3 seconds of CPU in spa_sync()
     thread (fix race condition)

References:
  https://www.illumos.org/issues/3552
  illumos/illumos-gate@03f8c366886542ed249a15d755ae78ea4e775d9d

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

Porting notes:

This fixes an upstream regression that was introduced in commit
zfsonlinux/zfs@e51be06697762215dc3b679f8668987034a5a048, which
ported the Illumos 3552 changes. This fix was added to upstream
rather quickly, but at the time of the port, no one spotted it and
the race was rare enough that it passed our regression tests. I
discovered this when comparing our metaslab.c to the illumos
metaslab.c.

Without this change it is possible for metaslab_group_alloc() to
consume a large amount of cpu time.  Since this occurs under a
mutex in a rcu critical section the kernel will log this to the
console as a self-detected cpu stall as follows:

  INFO: rcu_sched self-detected stall on CPU { 0}
  (t=60000 jiffies g=11431890 c=11431889 q=18271)

Closes #1687
Closes #1720
Closes #1731
Closes #1747