Remove zio_alloc_arena

We declare zio_alloc_arena using extern, but it does not appear to exist
anywhere in the code. This permits undefined behavior, so lets remove
it.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1614
Remove arc_data_buf_alloc()/arc_data_buf_free()

These functions are used in neither Illumos nor ZFSOnLinux. They appear
to have been replaced by arc_buf_alloc()/arc_buf_free(), so lets remove
them.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1614
Remove b_thawed from arc_buf_hdr_t

The code involving b_thawed appears to be dead, so lets discard it.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1614
dmu_tx: Fix possible NULL pointer dereference

dmu_tx_hold_object_impl can return NULL on error.  Check for this
condition prior to dereferencing pointer.  This can only occur if
the passed object was invalid or unallocated.

Signed-off-by: Nathaniel Clark <Nathaniel.Clark@misrule.us>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1610
Export additional dmu symbols

The dmu_prefetch, dmu_free_long_range, dmu_free_object,
dmu_prealloc, dmu_write_policy, and dmu_sync symbols have
been exported so they may be used by other modules.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add kmod repo integration

When the kmod packaging infrastructure was originally added the
dependency on the rpmfusion yum repositories was disabled.  This
was done at the time in favour of getting local builds working.

Now the time has come to conditionally re-enable that functionality
so we can properly provide binary kmod packages.

  ./configure --with-config=srpm
  make SRPM_DEFINE_KMOD='--define="repo rpmfusion"' srpm-kmod
  mock rebuild zfs-kmod-x.y.z-r.el6.src.rpm

One nice benefit of finishing this work is that the generic and
fedora spl-kmod spec files can be merged again.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>