Fix the creation of ZPOOL_HIST_CMD pool history entries.

Move the libzfs_fini() after the zpool_log_history() call so the
ZPOOL_HIST_CMD entry can get written.

Fix the handling of saved_poolname in zfsdev_ioctl()
which was broken as part of the stack-reduction work in
a16878805388c4d96cb8a294de965071d138a47b.

Since ZoL destroys the TSD data in which the previously successful
ioctl()'s pool name is stored following every vop, the ZFS_IOC_LOG_HISTORY
ioctl has a very important restriction: it can only successfully write
a long entry following a successful ioctl() if no intervening vops have
been performed.  Some of zfs subcommands do perform intervening vops and
to do the logging themselves. At the moment, the "create" and "clone"
subcommands have been modified appropriately.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1998
Add UNSHARING of filesystems and EXPORTING pools

As a 'stop' action ensure the filesystem is unshared before
it is unmounted, just in case.  Additionally, export the pool
so it may be cleanly imported by a different host.

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2003
Enable /etc/mtab cache to improve performance

Re-enable the /etc/mtab cache to prevent the zfs command from
having to repeatedly open and read from the /etc/mtab file.
Instead an AVL tree of the mounted filesystems is created and
used to vastly speed up lookups. This means that if non-zfs
filesystems are mounted concurrently the 'zfs mount' will not
immediately detect them.  In practice that will rarely happen
and even if it does the absolute worst case would be a failed
mount.  This was originally disabled out of an abundance of
paranoia.

NOTE: There may still be some parts of the code which do not
consult the mtab cache.  They should be updated to check the
mtab cache as they as discovered to be a problem.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Issue #845
Remove unconditional sharetab update

Removes the unconditional sharetab update when running any zfs
command. This means the sharetab might become out of date if
users are manually adding/removing shares with exportfs.  But
we shouldn't punish all callers to zfs in order to handle that
unlikely case. In the unlikely event we observe issues because
of this it can always be added back to just the share/unshare
call paths where we need an up to date sharetab.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Issue #845
Add ddt, ddt_entry, and l2arc_hdr caches

Back the allocations for ddt tables+entries and l2arc headers with
kmem caches.  This will reduce the cost of allocating these commonly
used structures and allow for greater visibility of them through the
/proc/spl/kmem/slab interface.

Signed-off-by: John Layman <jlayman@sagecloud.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1893
Define the needed ISA types for Sparc

Add the minimum required ISA types to support the Sparc
architecture.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: marku89 <mar42@kola.li>
Issue #1700
Use local variable to read zp->z_mode

When accessing the zp->z_mode through the SA bulk interface we
expect that 64-bits are available to hold the result.  However,
on 32-bit platforms mode_t will only be 32-bits so we cannot
pass it to SA_ADD_BULK_ATTR().  Instead a local uint64_t variable
must be used and the result assigned to zp->z_mode.

This went unnoticed on 32-bit little endian platforms because
the bytes happen to end up in the correct 32-bits.  But on big
endian platforms like Sparc the zp->z_mode will always end up
set to zero.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: marku89 <mar42@kola.li>
Issue #1700
Fix nvlist 'Bus Error' for Sparc

The mis-aligned memory accesses in nvpair_native_embedded() and
nvpair_native_embedded_array() will cause a 'Bus Error' for
architectures such as Sparc which not fully byte addressible.
To avoid this issue care is taken to avoid dereferencing the
potentially mis-aligned packed nvlist_t.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: marku89 <mar42@kola.li>
Issue #1700
Fix zfs_getattr_fast types

On Sparc sp->blksize will be a 64-bit value which is then cast
incorrectly to a 32-bit value.  For big endian systems this
results in an incorrect value for sp->blksize.  To resolve the
problem local variables of the correct size are used and then
assigned to sp->blksize.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: marku89 <mar42@kola.li>
Issue #1700
Force LZ4_FORCE_SW_BITCOUNT for Sparc

This change was proposed for Sparc but it's not clear to me
why it's required.  Proper support exists in the lz4 code to
detect the endianness and the required builtins are available
for gcc.  Still I'm including the patch because it will only
impact Sparc and it may resolve a case which hasn't occured
to me.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: marku89 <mar42@kola.li>
Issue #1700
Drain iput taskq outside z_teardown_lock

It's unsafe to drain the iput taskq while holding the z_teardown_lock
as a writer.  This is because when the last reference on an inode is
dropped it may still have pages which need to be written to disk.
This will be done through zpl_writepages which will acquire the
z_teardown_lock as a reader in ZFS_ENTER.  Therefore, if we're
holding the lock as a writer in zfs_sb_teardown the unmount will
deadlock.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Closes #1988
Merge remote-tracking branch 'zfsonlinux/master'