Commit Graph

22 Commits

Author SHA1 Message Date
Paul Dagnelie
fcff0f35bd Illumos 5960, 5925
5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>

References:
  https://www.illumos.org/issues/5960
  https://www.illumos.org/issues/5925
  https://github.com/illumos/illumos-gate/commit/a2cdcdd

Porting notes:
- [lib/libzfs/libzfs_sendrecv.c]
  - b8864a2 Fix gcc cast warnings
  - 325f023 Add linux kernel device support
  - 5c3f61e Increase Linux pipe buffer size on 'zfs receive'
- [module/zfs/zfs_vnops.c]
  - 3558fd7 Prototype/structure update for Linux
  - c12e3a5 Restructure zfs_readdir() to fix regressions
- [module/zfs/zvol.c]
  - Function @zvol_map_block() isn't needed in ZoL
  - 9965059 Prefetch start and end of volumes
- [module/zfs/dmu.c]
  - Fixed ISO C90 - mixed declarations and code
  - Function dmu_prefetch() 'int i' is initialized before
    the following code block (c90 vs. c99)
- [module/zfs/dbuf.c]
  - fc5bb51 Fix stack dbuf_hold_impl()
  - 9b67f60 Illumos 4757, 4913
  - 34229a2 Reduce stack usage for recursive traverse_visitbp()
- [module/zfs/dmu_send.c]
  - Fixed ISO C90 - mixed declarations and code
  - b58986e Use large stacks when available
  - 241b541 Illumos 5959 - clean up per-dataset feature count code
  - 77aef6f Use vmem_alloc() for nvlists
  - 00b4602 Add linux kernel memory support

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2016-01-08 15:08:19 -08:00
Matthew Ahrens
241b541574 Illumos 5959 - clean up per-dataset feature count code
5959 clean up per-dataset feature count code
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/5959
  https://github.com/illumos/illumos-gate/commit/ca0cc39

Porting notes:

illumos code doesn't check for feature_get_refcount() returning
ENOTSUP (which means feature is disabled) in zdb. zfsonlinux added
a check in https://github.com/zfsonlinux/zfs/commit/784652c
due to #3468. The check was reintroduced here.

Ported-by: Witaut Bajaryn <vitaut.bayaryn@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3965
2015-12-04 14:20:20 -08:00
Matthew Ahrens
f1512ee61e Illumos 5027 - zfs large block support
5027 zfs large block support
Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/5027
  https://github.com/illumos/illumos-gate/commit/b515258

Porting Notes:

* Included in this patch is a tiny ISP2() cleanup in zio_init() from
Illumos 5255.

* Unlike the upstream Illumos commit this patch does not impose an
arbitrary 128K block size limit on volumes.  Volumes, like filesystems,
are limited by the zfs_max_recordsize=1M module option.

* By default the maximum record size is limited to 1M by the module
option zfs_max_recordsize.  This value may be safely increased up to
16M which is the largest block size supported by the on-disk format.
At the moment, 1M blocks clearly offer a significant performance
improvement but the benefits of going beyond this for the majority
of workloads are less clear.

* The illumos version of this patch increased DMU_MAX_ACCESS to 32M.
This was determined not to be large enough when using 16M blocks
because the zfs_make_xattrdir() function will fail (EFBIG) when
assigning a TX.  This was immediately observed under Linux because
all newly created files must have a security xattr created and
that was failing.  Therefore, we've set DMU_MAX_ACCESS to 64M.

* On 32-bit platforms a hard limit of 1M is set for blocks due
to the limited virtual address space.  We should be able to relax
this one the ABD patches are merged.

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #354
2015-05-11 12:23:16 -07:00
Matthew Ahrens
3d45fdd6c0 Illumos 4951 - ZFS administrative commands should use reserved space
4951 ZFS administrative commands should use reserved space, not with ENOSPC
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Garrett D'Amore <garrett@damore.org>

References:
  https://www.illumos.org/issues/4373
  https://github.com/illumos/illumos-gate/commit/7d46dc6

Ported by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-05-04 09:41:10 -07:00
Justin T. Gibbs
0c66c32d1d Illumos 5056 - ZFS deadlock on db_mtx and dn_holds
5056 ZFS deadlock on db_mtx and dn_holds
Author: Justin Gibbs <justing@spectralogic.com>
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/5056
  https://github.com/illumos/illumos-gate/commit/bc9014e

Porting Notes:

sa_handle_get_from_db():
  - the original patch includes an otherwise unmentioned fix for a
    possible usage of an uninitialised variable

dmu_objset_open_impl():
  - Under Illumos list_link_init() is the same as filling a list_node_t
    with NULLs, so they don't notice if they miss doing list_link_init()
    on a zero'd containing structure (e.g. allocated with kmem_zalloc as
    here). Under Linux, not so much: an uninitialised list_node_t goes
    "Boom!" some time later when it's used or destroyed.

dmu_objset_evict_dbufs():
  - reduce stack usage using kmem_alloc()

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-04-28 16:25:34 -07:00
Justin T. Gibbs
d683ddbb72 Illumos 5314 - Remove "dbuf phys" db->db_data pointer aliases in ZFS
5314 Remove "dbuf phys" db->db_data pointer aliases in ZFS
Author: Justin T. Gibbs <justing@spectralogic.com>
Reviewed by: Andriy Gapon <avg@freebsd.org>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Will Andrews <willa@spectralogic.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/5314
  https://github.com/illumos/illumos-gate/commit/c137962

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-04-28 16:25:20 -07:00
Jerry Jelinek
788eb90c4c Illumos 3897 - zfs filesystem and snapshot limits
3897 zfs filesystem and snapshot limits
Author: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>

References:
  https://www.illumos.org/issues/3897
  https://github.com/illumos/illumos-gate/commit/a2afb61

Porting Notes:

dsl_dataset_snapshot_check(): reduce stack usage using kmem_alloc().

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-04-28 16:22:51 -07:00
Brian Behlendorf
79c76d5b65 Change KM_PUSHPAGE -> KM_SLEEP
By marking DMU transaction processing contexts with PF_FSTRANS
we can revert the KM_PUSHPAGE -> KM_SLEEP changes.  This brings
us back in line with upstream.  In some cases this means simply
swapping the flags back.  For others fnvlist_alloc() was replaced
by nvlist_alloc(..., KM_PUSHPAGE) and must be reverted back to
fnvlist_alloc() which assumes KM_SLEEP.

The one place KM_PUSHPAGE is kept is when allocating ARC buffers
which allows us to dip in to reserved memory.  This is again the
same as upstream.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 14:41:26 -08:00
Matthew Ahrens
5dbd68a352 Illumos 4914 - zfs on-disk bookmark structure should be named *_phys_t
4914 zfs on-disk bookmark structure should be named *_phys_t

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  https://www.illumos.org/issues/4914
  https://github.com/illumos/illumos-gate/commit/7802d7b

Porting notes:

There were a number of zfsonlinux-specific uses of zbookmark_t which
needed to be updated.  This should reduce the likelihood of further
problems like issue #2094 from occurring.

Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2558
2014-08-06 14:48:41 -07:00
Matthew Ahrens
9b67f60560 Illumos 4757, 4913
4757 ZFS embedded-data block pointers ("zero block compression")
4913 zfs release should not be subject to space checks

Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Max Grossman <max.grossman@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/4757
  https://www.illumos.org/issues/4913
  https://github.com/illumos/illumos-gate/commit/5d7b4d4

Porting notes:

For compatibility with the fastpath code the zio_done() function
needed to be updated.  Because embedded-data block pointers do
not require DVAs to be allocated the associated vdevs will not
be marked and therefore should not be unmarked.

Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2544
2014-08-01 14:28:05 -07:00
Matthew Ahrens
da536844d5 Illumos 4368, 4369.
4369 implement zfs bookmarks
4368 zfs send filesystems from readonly pools
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

References:
  https://www.illumos.org/issues/4369
  https://www.illumos.org/issues/4368
  https://github.com/illumos/illumos-gate/commit/78f1710

Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2530
2014-07-29 10:55:29 -07:00
Max Grossman
b0bc7a84d9 Illumos 4370, 4371
4370 avoid transmitting holes during zfs send
4371 DMU code clean up

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Approved by: Garrett D'Amore <garrett@damore.org>a

References:
  https://www.illumos.org/issues/4370
  https://www.illumos.org/issues/4371
  https://github.com/illumos/illumos-gate/commit/43466aa

Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2529
2014-07-28 14:29:58 -07:00
Matthew Ahrens
fa86b5dbb6 Illumos 4171, 4172
4171 clean up spa_feature_*() interfaces
4172 implement extensible_dataset feature for use by other zpool features

Reviewed by: Max Grossman <max.grossman@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Approved by: Garrett D'Amore <garrett@damore.org>a

References:
  https://www.illumos.org/issues/4171
  https://www.illumos.org/issues/4172
  https://github.com/illumos/illumos-gate/commit/2acef22

Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2528
2014-07-25 16:40:07 -07:00
Michael Kjorling
d1d7e2689d cstyle: Resolve C style issues
The vast majority of these changes are in Linux specific code.
They are the result of not having an automated style checker to
validate the code when it was originally written.  Others were
caused when the common code was slightly adjusted for Linux.

This patch contains no functional changes.  It only refreshes
the code to conform to style guide.

Everyone submitting patches for inclusion upstream should now
run 'make checkstyle' and resolve any warning prior to opening
a pull request.  The automated builders have been updated to
fail a build if when 'make checkstyle' detects an issue.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1821
2013-12-18 16:46:35 -08:00
Matthew Ahrens
b663a23d36 Illumos #4047
4047 panic from dbuf_free_range() from dmu_free_object() while
     doing zfs receive
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@nexenta.com>

References:
  https://www.illumos.org/issues/4047
  illumos/illumos-gate@713d6c2088

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

Porting notes:

1. The exported symbol dmu_free_object() was renamed to
   dmu_free_long_object() in Illumos.
2013-11-05 12:23:35 -08:00
Matthew Ahrens
1958067629 Illumos #3888
3888 zfs recv -F should destroy any snapshots created since
     the incremental source
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Peng Dai <peng.dai@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/3888
  illumos/illumos-gate@34f2f8cf94

Porting notes:

1. Commit 1fde1e3720 wrapped a
   declaration in dsl_dataset_modified_since_lastsnap in ASSERTV().
   The ASSERTV() and local variable have been removed to avoid an
   unused variable warning.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Richard Yao <ryao@gentoo.org>
Issue #1775
2013-11-04 11:18:14 -08:00
Matthew Ahrens
1a077756e8 Illumos #3829
3829 fix for 3740 changed behavior of zfs destroy/hold/release ioctl
Reviewed by: Matt Amdur <matt.amdur@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/3829
  illumos/illumos-gate@bb6e70758d

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
2013-11-04 11:18:14 -08:00
Steven Hartland
95fd54a1c5 Illumos #3740
3740 Poor ZFS send / receive performance due to snapshot
     hold / release processing
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>

References:
  https://www.illumos.org/issues/3740
  illumos/illumos-gate@a7a845e4bf

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

Porting notes:

1. 13fe019870 introduced a merge conflict
   in dsl_dataset_user_release_tmp where some variables were moved
   outside of the preprocessor directive.

2. dea9dfefdd747534b3846845629d2200f0616dad made the previous merge
   conflict worse by switching KM_SLEEP to KM_PUSHPAGE. This is notable
   because this commit refactors the code, adding a new KM_SLEEP
   allocation. It is not clear to me whether this should be converted
   to KM_PUSHPAGE.

3. We had a merge conflict in libzfs_sendrecv.c because of copyright
   notices.

4. Several small C99 compatibility fixed were made.
2013-11-04 11:17:48 -08:00
George Wilson
2696dfafd9 Illumos #3642, #3643
3642 dsl_scan_active() should not issue I/O to determine if async
     destroying is active
3643 txg_delay should not hold the tc_lock
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>

References:
  https://www.illumos.org/issues/3642
  https://www.illumos.org/issues/3643
  illumos/illumos-gate@4a92375985

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

Porting Notes:

1. The alignment assumptions for the tx_cpu structure assume that
   a kmutex_t is 8 bytes.  This isn't true under Linux but tc_pad[]
   was adjusted anyway for consistency since this structure was
   never carefully aligned in ZoL.  If careful alignment does impact
   performance significantly this should be reworked to be portable.
2013-11-01 08:55:12 -07:00
Matthew Ahrens
2e528b49f8 Illumos #3598
3598 want to dtrace when errors are generated in zfs
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

References:
  https://www.illumos.org/issues/3598
  illumos/illumos-gate@be6fd75a69

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

Porting notes:

1. include/sys/zfs_context.h has been modified to render some new
   macros inert until dtrace is available on Linux.

2. Linux-specific changes have been adapted to use SET_ERROR().

3. I'm NOT happy about this change.  It does nothing but ugly
   up the code under Linux.  Unfortunately we need to take it to
   avoid more merge conflicts in the future.  -Brian
2013-10-31 14:58:04 -07:00
Kohsuke Kawaguchi
77831e1738 Reduce the stack usage of dsl_dataset_remove_clones_key
dataset_remove_clones_key does recursion, so if the recursion goes
deep it can overrun the linux kernel stack size of 8KB. I have seen
this happen in the actual deployment, and subsequently confirmed it by
running a test workload on a custom-built kernel that uses 32KB stack.

See the following stack trace as an example of the case where it would
have run over the 8KB stack kernel:

        Depth    Size   Location    (42 entries)
        -----    ----   --------
  0)    11192      72   __kmalloc+0x2e/0x240
  1)    11120     144   kmem_alloc_debug+0x20e/0x500
  2)    10976      72   dbuf_hold_impl+0x4a/0xa0
  3)    10904     120   dbuf_prefetch+0xd3/0x280
  4)    10784      80   dmu_zfetch_dofetch.isra.5+0x10f/0x180
  5)    10704     240   dmu_zfetch+0x5f7/0x10e0
  6)    10464     168   dbuf_read+0x71e/0x8f0
  7)    10296     104   dnode_hold_impl+0x1ee/0x620
  8)    10192      16   dnode_hold+0x19/0x20
  9)    10176      88   dmu_buf_hold+0x42/0x1b0
 10)    10088     144   zap_lockdir+0x48/0x730
 11)     9944     128   zap_cursor_retrieve+0x1c4/0x2f0
 12)     9816     392   dsl_dataset_remove_clones_key.isra.14+0xab/0x190
 13)     9424     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 14)     9032     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 15)     8640     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 16)     8248     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 17)     7856     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 18)     7464     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 19)     7072     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 20)     6680     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 21)     6288     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 22)     5896     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 23)     5504     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 24)     5112     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 25)     4720     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 26)     4328     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 27)     3936     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 28)     3544     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 29)     3152     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 30)     2760     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 31)     2368     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 32)     1976     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 33)     1584     392   dsl_dataset_remove_clones_key.isra.14+0x10c/0x190
 34)     1192     232   dsl_dataset_destroy_sync+0x311/0xf60
 35)      960      72   dsl_sync_task_group_sync+0x12f/0x230
 36)      888     168   dsl_pool_sync+0x48b/0x5c0
 37)      720     184   spa_sync+0x417/0xb00
 38)      536     184   txg_sync_thread+0x325/0x5b0
 39)      352      48   thread_generic_wrapper+0x7a/0x90
 40)      304     128   kthread+0xc0/0xd0
 41)      176     176   ret_from_fork+0x7c/0xb0

This change reduces the stack usage in dsl_dataset_remove_clones_key
by allocating structures in heap, not in stack.  This is not a fundamental
fix, as one can create an arbitrary large data set that runs over any
fixed size stack, but this will make the problem far less likely.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Kohsuke Kawaguchi <kk@kohsuke.org>
Closes #1726
2013-09-25 15:18:32 -07:00
Matthew Ahrens
13fe019870 Illumos #3464
3464 zfs synctask code needs restructuring
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

References:
  https://www.illumos.org/issues/3464
  illumos/illumos-gate@3b2aab1880

Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1495
2013-09-04 16:01:24 -07:00