Fix regression introduced in port of Illumos #3744

Remove the redundant call to zfs_unmount_snap() which was being
done after char array was freed,

This fixes an upstream regression that was introduced in commit
zfsonlinux/zfs@d09f25dc66774959499a89bf3680d09c6e541ce8, which
ported the Illumos 3744 changes.

Signed-off-by: Andrey Vesnovaty <andrey.vesnovaty@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #2156
Revert "sighandler() should take 2 arguments"

This reverts commit 0bb89b6c594259829556f6dea5a89e722f214fd3 in
favor of a cleaner implementation.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2182
sighandler() should take 2 arguments

Stopping arcstat.py with ^C always ends up with error:
TypeError: sighandler() takes no arguments (2 given)

Since no special signal handling was done in sighandler(),
it's simpler to just set SIGINT handler to SIG_DFL, which
terminates the script.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Isaac Huang <he.huang@intel.com>
Closes #2179
Assert alignment in umem_alloc_aligned

Valgrind suggests that the address we are returning is not properly
aligned, so lets add an assertion.

==87740==  Address 0x1012a22a is 554 bytes inside a block of size 4,096
alloc'd
==87740==    at 0x4C2BBA0: memalign (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==87740==    by 0x4C2BCC7: posix_memalign (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==87740==    by 0x52FA845: zio_buf_alloc (umem.h:101)
==87740==    by 0x52F6226: zil_alloc_lwb (zil.c:463)
==87740==    by 0x52F8559: zil_commit (zil.c:566)
==87740==    by 0x40611D: ztest_freeze (ztest.c:5909)
==87740==    by 0x4066A7: ztest_init (ztest.c:6048)
==87740==    by 0x407AF4: main (ztest.c:6226)

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2174
Implement -t option to zpool import for temporary pool names

Originally, users had to handle spa namespace collisions by either
exporting the already imported pool or by specifying a new name for the
pool with a conflicting name. In the case of root pools from virtual
guests, neither approach to collision resolution is reasonable. This is
addressed by extending the new name syntax with a -t option to specify
that the new name is temporary. When specified, this sets an internal
flag that is passed into the kernel to tell it that all label updates
should refer to the name used in the original label. Consequently, the
original pool name will be retained on export.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2189
config: compile test rather than run test

When testing compiler flags, we only need to do compile test. Otherwise,
configure will fail with "configure: error: cannot run test program while
cross compiling" when cross compiling.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2191