Make user stack limit configurable

To aid in detecting and debugging stack overflow issues make the
user space stack limit configurable via a new ZFS_STACK_SIZE
environment variable.  The value assigned to ZFS_STACK_SIZE will
be used as the default stack size in bytes.

Because this is mainly useful as a debugging aid in conjunction
with ztest the stack limit is disabled by default.  See the ztest(1)
man page for additional details on using the ZFS_STACK_SIZE
environment variable.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #2743
Issue #2293
Add add_prop_list_default helper

Adding to a property list only if there is no existing value is used
twice. Once by zpool create -R and again by zpool import -R. Now that
zpool create -t and zpool import -t also need it, lets refactor it into
a helper function to make the code more readable.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2417
zpool import -t should not update cachefile

zpool import's -t parameter is intended for use with -R when operating
on pools that belong to other systems. Like -R, pools imported in this
way should not update the cachefile unless explicitly requested. The
initial implementation allowed the cachefile to be updated when -R was
not used. This went uncaught during testing because -R had implicitly
disabled use of the cachefile.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2417
Implement -t option to zpool create for temporary pool names

Creating virtual machines that have their rootfs on ZFS on hosts that
have their rootfs on ZFS causes SPA namespace collisions when the
standard name rpool is used. The solution is either to give each guest
pool a name unique to the host, which is not always desireable, or boot
a VM environment containing an ISO image to install it, which is
cumbersome.

26b42f3f9d03f85cc7966dc2fe4dfe9216601b0e introduced `zpool import -t
...` to simplify situations where a host must access a guest's pool when
there is a SPA namespace conflict. We build upon that to introduce
`zpool import -t tname ...`. That allows us to create a pool whose
in-core name is tname, but whose on-disk name is the normal name
specified.

This simplifies the creation of machine images that use a rootfs on ZFS.
That benefits not only real world deployments, but also ZFSOnLinux
development by decreasing the time needed to perform rootfs on ZFS
experiments.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2417
FreeBSD PR kern/172259: Fixes zfs receive errors

FreeBSD PR kern/172259: Fixes zfs receive errors caused by snapshot
replication being processed in a random order instead of creation
order.

Eliminates needless filesystem renames caused by removed parent
snapshots which subsequently causes many more errors.

PR:		kern/172259
Submitted by:	Steven Hartland
Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks

References:
  https://github.com/freebsd/freebsd/commit/4995789

Porting notes:

Minor whitespace fixes were made to conform with style requirements:

lib/libzfs/libzfs_sendrecv.c: 2269: indent by spaces instead of tabs
lib/libzfs/libzfs_sendrecv.c: 2270: indent by spaces instead of tabs

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2729
zfs send -p send properties only for snapshots that are actually sent

... as opposed to sending properties of all snapshots of the relevant
filesystem.  The previous behavior results in properties being set on
all snapshots on the receiving side, which is quite slow.

Behavior of zfs send -R is not changed.

References:
  http://thread.gmane.org/gmane.comp.file-systems.openzfs.devel/346

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2729
Issue #2210
=> 1099: turbo/iscsi - This is iSCSI sharing for ZoL (shareiscsi).
* Supports the following iSCSI implementations (in this order of discovery):
  + IET         http://iscsitarget.sourceforge.net
  + STGT        http://stgt.berlios.de
  + SCST        http://scst.sourceforge.net
    + Requires that SCST was compiled with /sys support (the default).
  + LIO         http://linux-iscsi.org
* Will refuse to unshares an active target (one with sessions).
* Supports the following options to the 'shareiscsi' property:
  + name/iqn    Full iSCSI Qualified Name (IQN), including identifier.
                This is generated by iscsi_generate_target():
                + Uses the content of an optional /etc/iscsi_target_id file:
                  Example: iqn.YYYY-MM.tld.domain
                + If this file doesn't exist, it uses todays year, month and
                  domain name to generate the iqn.
                + The dataset name is appended at the end of the iqn, with
                  slashes replaced with dots.
                  => <iqn>:<dataset>
  + lun         LUN (0-16384)
                Default: 0 (1 for STGT)
  + type        Share mode (fileio, blockio, nullio, disk, tape)
                STGT: ssc, pt
                Default: blockio (disk for STGT)
  + iomode      IO mode (wb, wt, ro)
                STGT: rdwr, aio, mmap, sg, ssc
                Default: wt (rdwr for STGT)
  + blocksize   Logical block size (512, 1024, 2048, 4096)
                Default: Volume blocksize, 4096 if not usable.
                NOTE: Currently not supported for STGT (doesn't seem to be
                      an option for it in tgtadm).
  + initiator   Allow only this initiator to bind to target.
                Currently only availible for LIO and STGT.
  + authname    Global user to use in binds on targets.
  + authpass    Password for global user.
* If not called with a 'name/iqn' value, then force setting it.
  This so that the IQN doesn't change every month (when it is
  regenerated again). It will be generated by iscsi_generate_target()
  (see above).

NOTE:
+ Moved nfs.c:foreach_nfs_shareopt() to libshare.c:foreach_shareopt()
  so that it can be (re)used in smb.c and iscsi.c.
+ Use the list_{create,insert}() etc for keeping tabs of the linked lists
  instead of using a home-made version.
+ A half second delay had to be added in lib/libzfs/libzfs_mount.c:zfs_unmount()
  after the successful unshare. This to avoid 'dataset busy' when destroying
  recursivly.
+ Fix some gcc-4.8.1 compile fixes. Thanx to munix9.
+ Fix error in manpage.
+ Don't set last char in domainname to NULL willy-nilly. Only if newline.
+ Instead of blindingly generate an IQN, use opts->name if it's set.
+ Split iSCSI implementation into their own separate source files
+ The 'initiator', 'authname' and 'authpass' option might have some issues:
  It will make the compatibility between the different iSCSI implementations
  questionable - can't switch between them easily (it will ONLY be availible
  in ZoL). I COULD make the option be silently ignored (instead of forcibly
  rejected if not availible).

  But that still doesn't solve the (possible) problem between ZoL and
  OpenZFS/Illumos (setting the option, will possibly introduce problems when
  importing the pool on something else than ZoL).

  So some more discussion might be needed..

Misc iSCSI fixes/cleanups/attempts to get 'zfs rename' to work.

!! Doesn't - a 'zfs rename' works, but most often than not, the rename
!! IOCTL hangs. Not every time and not always on the first dataset being
!! renamed... Seems a little to random to me.
=> 1476: turbo/smbfs_registry-shares - Rewrite of the Libshare/SMBFS
* Add support for options to 'sharesmb'.
  Fixes: #1182
  + Move nfs.c:foreach_nfs_shareopt() to libshare.c:foreach_shareopt()
    so that it can be (re)used in smb.c (and later iscsi.c).
  + Call net(8) with the guest_ok option.
  + Rewrite the sharesmb part of the zfs(8) manpage.
    + Add more examples
    + Inform about the (new) options to sharesmb.
  + Add STDERR_VERBOSE to libzfs_run_process() so that we
    can catch any errors from net(8).
  + Don't call smb_retrieve_shares() after enabling a share.
    No point, it's done when really needed anyway.
  + Support 'y', 'yes' and 'true' for guest_ok.
  * If sharesmb=on, just exit cleanly directly at the top of
    get_smb_shareopts_cb().
  * Remove param 2 and 3 from smb_enable_share_one(). That is
    availible in the first param - the impl_share struct.
  * Extra debugging added in smb_enable_share_one() - print
    all our options just before we call net(8).
* Add support for optional, extra script /sbin/zfs_share_smbfs
  to run after shareing is done.
  + Add an example zfs_share_smbfs script
* The option sharesmb should not be inherited by childs.
  Samba is perfectly able to show child file systems...
* Use dataset name in comment, not the smb share name.
* Use REGISTRY SHARES instead of USER SHARES
  + These are a lot more configurable (more possibility to customize the share).
  + Remove the 'acl' option and replace it with 'writeable' instead.
  + On some machines, there is a "global" share. This isn't really a share,
    but the possibility to modify global options. So first get a line of
    _real_ shares using 'net conf listshares' and _then_ cyckle through
    them retrieving info with 'net conf showshare <share>'.
  + Add an example on how to modify a share after ZFS share and what man
    pages to use for more info.
* Speedups (less share retreivals) and make sure the 'net' command is executable.
  + Since smb_shares is global, we only retreive shares if it's NULL
    in smb_retrieve_shares(). It should limit the number of times we
    fork() and read shares (which takes time).
  + If the net command don't exist (is executable), don't even register
    the smb fstype in libshare_smb_init().
  + access() fix - check if NET_CMD_PATH is _executable_ not just 'exists'.
* Run cstyle.pl to fix any code style problems.
* Output error if 'net' can't talk to samba.
* Improve error message if 'net' isn't executable.
* Move the checks from smb_available() to libshare_smb_init()
  to avoid doing them multiple times.
* Convert homemade linked list to the ZFS versions list_* functions (which uses a link_t).
* Script to list SMB shares added.
* Comment out a call to zfs_unshare_smb(). Don't seem to be needed.
  This because zfs_unshare_smb() is called twice if setting 'sharesmb=off' - once
  'somewhere else' and once here (this one AFTER the share have been unshared). That
  makes this one fail! Don't know if this is correct, but it works to comment out this...
=> 2087: turbo/initramfs - Initramfs scripts for ZoL.

Initramfs scripts for ZoL.
* Put in /usr/share/initramfs-tools/ or /etc/initramfs-tools/.
* With pull request #1476 (not yet merged) comes a verbose warning
  if /usr/bin/net doesn't exist or isn't executable. Just create
  a dummy...
* If user haven't specified pool, but bootfs then use the first part
  of the bootfs path as pool name.
* Add support for booting of a ZFS snapshot.
  Do this by cloning the snapshot into a dataset. If this the resulting
  dataset already exists, destroy it. Then set mountpoint=/ on that
  dataset and mount it on root.
  + If snapshot does not exist, use base dataset (the part before '@')
    as boot filesystem instead.
* Add support for more kernel command line arguments (ideas taken from
  the Fedora/Redhat dracut script):
  + (zfs_force|zfs.force|zfsforce)=(on|yes|1) (ignore case).
  + root=zfs:AUTO => try to find rootfs automatically.
  + root=zfs:<dataset>
  + root=ZFS=<dataset>
* Remove the existing '-f' option to 'zpool import', instead let
  this be controlled on the kernel command line.
* Do not force-set mountpoint=/ - should (??) not be nessesary.
* Support mounting a rootfs with mountpoint=legacy
* Support both RPM based and DEB based system by removing the logic
  from the dracut script and instead use the logic in scripts/zfs-initramfs/scripts/zfs
  for both Debian GNU/Linux (etc) and RedHat/Fedora (etc).
* Only run the local-* script(s) if/when it/they exists.
* Don't auto import pools when loading module - keep better control of the imports.
* If called with only 'rpool' (or only 'zfs-bootfs'), then fake it by setting 'root=zfs:AUTO'
  (to avoid duplication of code etc) so that it will be auto detected later.
  + If pool is specified and we're auto discovering, don't go through ALL pools, only the one we specified.
* Rewrite the auto detection of bootfs in the auto detector.
* Only try to import pool if it haven't already been imported (in the auto detector).
* Add support for only having 'root=pool/dataset' option.
* Remove the use of setting 'ZFS_RPOOL=rpool'. No longer nessesary.
* Check if /scripts/local-* is either file or directory - should be dir, but just to be safe check both.
* Make wait_for_udev wait for 10 seconds.
* Add a configurable ZFS_INITRD_POST_MODPROBE_SLEEP (set in /etc/default/zfs) after the modprobe.
* Merge https://github.com/zfsonlinux/zfs/pull/2196.
  Remove lines that contain only a hyphen (match '^-$' instead of '-').
* Add a 'default' file to go in '/etc/default/zfs'.
* Support mounting additional filesystems (such as /var and /usr etc)
  in the initrd using ZFS_INITRD_ADDITIONAL_DATASETS set in /etc/defaults/zfs.
* Add exceptions to pool imports.
  + Both for init and initrd script.
* Make sure that the zpool.cache file is actually copied onto the initrd!!
* Include /etc/modprobe.d/{zfs,spl}.conf in the initrd if they exist.
* Export all pools found after the modprobe - zfs_autoimport_disable=1'
  don't seem to be working in >= 0.6.3.
  + This snippet will go away as soon as I can figure out why it doesn't,
    it's ugly!!
* Only try /dev/disk/by-* in the initrd if USE_DISK_BY_ID is set.
  + Try this first, then fallback to using the cache file if that exist.
=> 2106: turbo/fixes.init_total_rewrite - Base scripts on the init scripts included with Debian GNU/Linux

Base scripts on the init scripts included with Debian GNU/Linux
then take code from the already existing ones, trying to merge
them into one.
+ NFS server service is just called 'nfs' in Redhat based system, and
  nfs-kernel-server on Debian GNU/Linux based.
+ Merge https://github.com/zfsonlinux/zfs/pull/2148 - Inform OpenRC that ZFS uses mtab.
+ Stop after umountfs
+ When stopping, don't check for LOCKDIR/zfs-mount - it won't be mounted,
  so the file won't exist making the script not run.
+ Add a configurable ZFS_INITRD_POST_MODPROBE_SLEEP used in the initrd to sleep after the modprobe.
+ The import function, do_import(), imports pools by name instead of '-a' [all].
  + Test all '/dev/disk/by-*' dirs for import.
+ Fallback on importing the pool using the cache file (if it exists) if the
  'by-id' didn't work.
+ Add exceptions to pool imports.
=> 2726: turbo/debug_documentation - Remove *BSD example on how to retrieve debug log with working Linux commands.
=> 2727: turbo/zol-bug-report - Initial version of a ZoL "report issue" script.
=> 1082: turbo/issue-1082 - Support 'out of tree' builds

* Support 'out of tree' builds by adding the 'src' and 'obj' variables
  and removing the absolute path to the build results to the Makefile.in
  files below the module directory.

* For VPATH builds (addition for #1082):
  + Add '../../spl' to spl source directory list to search
  + Do a find in the found spl source for spl_config.h

Closes: #1082
=> 2376: turbo/issue-2033 - Exclude the /usr/lib/modules/*/modules.* files
                            they are regenerated at module pkg install by depmod.
=> 2512: turbo/issue-2448 - Default to --with-blkid in RPM packaging
                          - Make linking with and finding libblkid required

Default to --with-blkid in RPM packaging

Support for libblkid has been in the ZoL for years but has been
disabled by default in the packaging.  When libblkid is disabled
the 'zpool create' command will not warn you if you're going to
overwrite an existing filesystem.  For this reason the default
behavior has been changed to require libblkid.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2448

Make linking with and finding libblkid required (so that creating
pools on devices with existing filesystem will get a warning).
Use '--without-blkid' to explicitly disable this.

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Closes: #2448
=> 2683: turbo/issue-2562 - Add a vdev_size payload to the ereport if vdev_path is set.

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>

Closes: #2562
=> 2668: turbo/issue-2666 - Allow for "zfs receive" to skip existing snapshots
                            by adding the option "-s" to zfs receive.

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>

Closes: #2666
=> 2673: turbo/issue-2673 - Mount filesystem as soon as it's been received

Instead of storing the filesystem just received in top_zfs,
mount and share it directly in zfs_receive_one().

This will make a filesystem be mounted as soon as it's been received,
instead of waiting to the very end - which might take days.

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>

Closes: #2673
=> 3693: turbo/illumos-3693 - restore_object uses at least two transactions to restore an object

restore_object uses at least two transactions to restore an object:

  * one transaction is used for dmu_object_claim
  * another transaction is used to set compression, checksum and most
    importantly bonus data
  * furthermore dmu_object_reclaim internally uses multiple transactions
  * dmu_free_long_range frees chunks in separate transactions
  * dnode_reallocate is executed in a distinct transaction

The fact the dnode_allocate/dnode_reallocate are executed in one
transaction and bonus (re-)population is executed in a different
transaction may lead to violation of ZFS consistency assertions if the
transactions are assigned to different transaction groups.  Also, if
the first transaction group is successfully written to a permanent
storage, but the second transaction is lost, then an invalid dnode may
be created on the stable storage.

Reviewed by: Christopher Siden christopher.siden@delphix.com
Reviewed by: George Wilson george.wilson@delphix.com

Original authors: Matthew Ahrens and Andriy Gapon

References:
  https://www.illumos.org/projects/illumos-gate//issues/3693
  https://reviews.csiden.org/r/90

Ported by: Turbo Fredriksson <turbo@bayour.com>
=> 5134: turbo/illumos-5134 - if ZFS_DEBUG or debug= is set, libzpool should enable debug prints

Reviewed by: Christopher Siden christopher.siden@delphix.com
Reviewed by: Adam Leventhal adam.leventhal@delphix.com

References:
  https://www.illumos.org/projects/illumos-gate/issues/5134
  https://github.com/illumos/illumos-gate/commit/7fa49ea

Porting notes:
  Run dprintf_setup() in main.

Ported by: Turbo Fredriksson <turbo@bayour.com>