summaryrefslogtreecommitdiffstats
path: root/module/zfs/mmp.c
Commit message (Collapse)AuthorAgeFilesLines
* Use proper tag for spa config refcounts in mmp_write_uberblock()Tim Chase2019-01-251-1/+1
| | | | | | | | | This allows the spa config refcounts to use tracking in debug builds without triggering the "No such hold %p on refcount" panic. Reviewed-by: Olaf Faaland <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tim Chase <[email protected]> Closes #8326
* Update build system and packagingBrian Behlendorf2018-05-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Minimal changes required to integrate the SPL sources in to the ZFS repository build infrastructure and packaging. Build system and packaging: * Renamed SPL_* autoconf m4 macros to ZFS_*. * Removed redundant SPL_* autoconf m4 macros. * Updated the RPM spec files to remove SPL package dependency. * The zfs package obsoletes the spl package, and the zfs-kmod package obsoletes the spl-kmod package. * The zfs-kmod-devel* packages were updated to add compatibility symlinks under /usr/src/spl-x.y.z until all dependent packages can be updated. They will be removed in a future release. * Updated copy-builtin script for in-kernel builds. * Updated DKMS package to include the spl.ko. * Updated stale AUTHORS file to include all contributors. * Updated stale COPYRIGHT and included the SPL as an exception. * Renamed README.markdown to README.md * Renamed OPENSOLARIS.LICENSE to LICENSE. * Renamed DISCLAIMER to NOTICE. Required code changes: * Removed redundant HAVE_SPL macro. * Removed _BOOT from nvpairs since it doesn't apply for Linux. * Initial header cleanup (removal of empty headers, refactoring). * Remove SPL repository clone/build from zimport.sh. * Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due to build issues when forcing C99 compilation. * Replaced legacy ACCESS_ONCE with READ_ONCE. * Include needed headers for `current` and `EXPORT_SYMBOL`. Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Olaf Faaland <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Pavel Zakharov <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> TEST_ZIMPORT_SKIP="yes" Closes #7556
* module param callbacks check for initialized spaOlaf Faaland2018-05-111-1/+2
| | | | | | | | | | | | | | | | | | | | | | | Callbacks provided for module parameters are executed both after the module is loaded, when a user alters it via sysfs, e.g echo bar > /sys/modules/zfs/parameters/foo as well as when the module is loaded with an argument, e.g. modprobe zfs foo=bar In the latter case, the init functions likely have not run yet, including spa_init() which initializes the namespace lock so it is safe to use. Instead of immediately taking the namespace lock and attemping to iterate over initialized spa structures, check whether spa_mode_global is nonzero. This is set by spa_init() after it has initialized the namespace lock. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tim Chase <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7496 Closes #7521
* OpenZFS 7614, 9064 - zfs device evacuation/removalMatthew Ahrens2018-04-141-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | OpenZFS 7614 - zfs device evacuation/removal OpenZFS 9064 - remove_mirror should wait for device removal to complete This project allows top-level vdevs to be removed from the storage pool with "zpool remove", reducing the total amount of storage in the pool. This operation copies all allocated regions of the device to be removed onto other devices, recording the mapping from old to new location. After the removal is complete, read and free operations to the removed (now "indirect") vdev must be remapped and performed at the new location on disk. The indirect mapping table is kept in memory whenever the pool is loaded, so there is minimal performance overhead when doing operations on the indirect vdev. The size of the in-memory mapping table will be reduced when its entries become "obsolete" because they are no longer used by any block pointers in the pool. An entry becomes obsolete when all the blocks that use it are freed. An entry can also become obsolete when all the snapshots that reference it are deleted, and the block pointers that reference it have been "remapped" in all filesystems/zvols (and clones). Whenever an indirect block is written, all the block pointers in it will be "remapped" to their new (concrete) locations if possible. This process can be accelerated by using the "zfs remap" command to proactively rewrite all indirect blocks that reference indirect (removed) vdevs. Note that when a device is removed, we do not verify the checksum of the data that is copied. This makes the process much faster, but if it were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy the wrong data, when we have the correct data on e.g. the other side of the mirror. At the moment, only mirrors and simple top-level vdevs can be removed and no removal is allowed if any of the top-level vdevs are raidz. Porting Notes: * Avoid zero-sized kmem_alloc() in vdev_compact_children(). The device evacuation code adds a dependency that vdev_compact_children() be able to properly empty the vdev_child array by setting it to NULL and zeroing vdev_children. Under Linux, kmem_alloc() and related functions return a sentinel pointer rather than NULL for zero-sized allocations. * Remove comment regarding "mpt" driver where zfs_remove_max_segment is initialized to SPA_MAXBLOCKSIZE. Change zfs_condense_indirect_commit_entry_delay_ticks to zfs_condense_indirect_commit_entry_delay_ms for consistency with most other tunables in which delays are specified in ms. * ZTS changes: Use set_tunable rather than mdb Use zpool sync as appropriate Use sync_pool instead of sync Kill jobs during test_removal_with_operation to allow unmount/export Don't add non-disk names such as "mirror" or "raidz" to $DISKS Use $TEST_BASE_DIR instead of /tmp Increase HZ from 100 to 1000 which is more common on Linux removal_multiple_indirection.ksh Reduce iterations in order to not time out on the code coverage builders. removal_resume_export: Functionally, the test case is correct but there exists a race where the kernel thread hasn't been fully started yet and is not visible. Wait for up to 1 second for the removal thread to be started before giving up on it. Also, increase the amount of data copied in order that the removal not finish before the export has a chance to fail. * MMP compatibility, the concept of concrete versus non-concrete devices has slightly changed the semantics of vdev_writeable(). Update mmp_random_leaf_impl() accordingly. * Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool feature which is not supported by OpenZFS. * Added support for new vdev removal tracepoints. * Test cases removal_with_zdb and removal_condense_export have been intentionally disabled. When run manually they pass as intended, but when running in the automated test environment they produce unreliable results on the latest Fedora release. They may work better once the upstream pool import refectoring is merged into ZoL at which point they will be re-enabled. Authored by: Matthew Ahrens <[email protected]> Reviewed-by: Alex Reece <[email protected]> Reviewed-by: George Wilson <[email protected]> Reviewed-by: John Kennedy <[email protected]> Reviewed-by: Prakash Surya <[email protected]> Reviewed by: Richard Laager <[email protected]> Reviewed by: Tim Chase <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Garrett D'Amore <[email protected]> Ported-by: Tim Chase <[email protected]> Signed-off-by: Tim Chase <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7614 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1eb Closes #6900
* Fix divide-by-zero in mmp_delay_update()Olaf Faaland2018-04-061-1/+1
| | | | | | | | | | | | vdev_count_leaves() in the denominator may return 0, caught by Coverity. Introduced by * 533ea04 Update mmp_delay on sync or skipped, failed write Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7391
* Update mmp_delay on sync or skipped, failed writeOlaf Faaland2018-04-041-40/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When an MMP write is skipped, or fails, and time since mts->mmp_last_write is already greater than mts->mmp_delay, increase mts->mmp_delay. The original code only updated mts->mmp_delay when a write succeeded, but this results in the write(s) after delays and failed write(s) reporting an ub_mmp_delay which is too low. Update mmp_last_write and mmp_delay if a txg sync was successful. At least one uberblock was written, thus extending the time we can be sure the pool will not be imported by another host. Do not allow mmp_delay to go below (MSEC2NSEC(zfs_multihost_interval) / vdev_count_leaves()) so that a period of frequent successful MMP writes, e.g. due to frequent txg syncs, does not result in an import activity check so short it is not reliable based on mmp thread writes alone. Remove unnecessary local variable, start. We do not use the start time of the loop iteration. Add a debug message in spa_activity_check() to allow verification of the import_delay value and to prove the activity check occurred. Alter the tests that import pools and attempt to detect an activity check. Calculate the expected duration of spa_activity_check() based on module parameters at the time the import is performed, rather than a fixed time set in mmp.cfg. The fixed time may be wrong. Also, use the default zfs_multihost_interval value so the activity check is longer and easier to recognize. Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7330
* Report pool suspended due to MMPOlaf Faaland2018-03-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | When the pool is suspended, record whether it was due to an I/O error or due to MMP writes failing to succeed within the required time. Change spa_suspended from uint8_t to zio_suspend_reason_t to store the reason. When userspace queries pool status via spa_tryimport(), report the reason the pool was suspended in a new key, ZPOOL_CONFIG_SUSPENDED_REASON. In libzfs, when interpreting the returned config nvlist, report suspension due to MMP with a new pool status enum value, ZPOOL_STATUS_IO_FAILURE_MMP. In status_callback(), which generates and emits the message when 'zpool status' is executed, add a case to print an appropriate message for the new pool status enum value. Reviewed-by: George Melikov <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7296
* Fix MMP write frequency for large poolsBrian Behlendorf2018-03-121-3/+3
| | | | | | | | | | | | | | | | | | | When a single pool contains more vdevs than the CONFIG_HZ for for the kernel the mmp thread will not delay properly. Switch to using cv_timedwait_sig_hires() to handle higher resolution delays. This issue was reported on Arch Linux where HZ defaults to only 100 and this could be fairly easily reproduced with a reasonably large pool. Most distribution kernels set CONFIG_HZ=250 or CONFIG_HZ=1000 and thus are unlikely to be impacted. Reviewed-by: George Melikov <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Olaf Faaland <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #7205 Closes #7289
* Handle zio_resume and mmp => offOlaf Faaland2018-03-091-4/+10
| | | | | | | | | | | | | | | When multihost is disabled on a pool, and the pool is resumed via zpool clear, within a single cycle of the mmp thread's loop (e.g. while it's in the cv_timedwait call), both mmp_last_write and mmp_delay should be updated. The original code mistakenly treated the two cases as if they could not occur at the same time. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7286
* Record skipped MMP writes in multihost_historyOlaf Faaland2018-03-061-25/+89
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Once per pass through the MMP thread's loop, the vdev tree is walked to find a suitable leaf to write the next MMP block to. If no such leaf is found, the thread sleeps for a while and resumes at the top of the loop. Add an entry to multihost_history when no leaf can be found, and record the reason in the error column. The error code for such entries is a bitfield, displayed in hex: 0x1 At least one vdev (interior or leaf) was not writeable. 0x2 At least one writeable leaf vdev was found, but it had a pending MMP write. timestamp = the time in seconds since the epoch when no leaf could be found originally. duration = the time (in ns) during which no MMP block was written for this reason. This does not include the preceeding inter-write period nor the following inter-write period. vdev_guid = the number of sequential cycles of the MMP thread looop when this occurred. Sample output, truncated to fit: For records of skipped MMP writes the right-most column, vdev_path, is reported as "-". id txg timestamp error duration mmp_delay vdev_guid ... 936 11 1520036441 0 146264 891422313 1740883117838 ... 937 11 1520036441 0 163956 888356657 7320395061548 ... 938 11 1520036442 0 130690 885314969 7320395061548 ... 939 11 1520036442 0 2001068577 882296582 1740883117838 ... 940 11 1520036443 0 161806 882296582 7320395061548 ... 941 11 1520036443 0x2 0 998020546 1 ... 942 11 1520036444 0 136585 998020546 7320395061548 ... 943 11 1520036444 0x2 0 998020257 1 ... 944 11 1520036445 5 2002662964 994160219 1740883117838 ... 945 11 1520036445 0x2 998073118 994160219 3 ... 946 11 1520036447 0 247136 994160219 7320395061548 ... Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7212
* Detect long config lock acquisition in mmpOlaf Faaland2018-03-061-0/+6
| | | | | | | | | | | | | | If something holds the config lock as a writer for too long, MMP will fail to issue MMP writes in a timely manner. This will result either in the pool being suspended, or in an extreme case, in the pool not being protected. If the time to acquire the config lock exceeds 1/10 of the minimum zfs_multihost_interval, report it in the zfs debug log. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7212
* Report duration and error in mmp_history entriesOlaf Faaland2018-02-221-2/+11
| | | | | | | | | | | | | | | | | | | | | | After an MMP write completes, update the relevant mmp_history entry with the time between submission and completion, and the error status of the write. [faaland1@toss3a zfs]$ cat /proc/spl/kstat/zfs/pool/multihost 39 0 0x01 100 8800 69147946270893 72723903122926 id txg timestamp error duration mmp_delay vdev_guid 10607 1166 1518985089 0 138301 637785455 4882... 10608 1166 1518985089 0 136154 635407747 1151... 10609 1166 1518985089 0 803618560 633048078 9740... 10610 1166 1518985090 0 144826 633048078 4882... 10611 1166 1518985090 0 164527 666187671 1151... Where duration = gethrtime_in_done_fn - gethrtime_at_submission, and error = zio->io_error. Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7190
* Do not initiate MMP writes while pool is suspendedOlaf Faaland2018-02-221-1/+1
| | | | | | | | | | | While the pool is suspended on host A, it may be imported on host B. If host A continued to write MMP blocks, it would be blindly overwriting MMP blocks written by host B, and the blocks written by host A would have outdated txg information. Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7182
* mmp should use a fixed tag for spa_config lockssanjeevbagewadi2018-02-121-2/+3
| | | | | | | | | | | mmp_write_uberblock() and mmp_write_done() should the same tag for spa_config_locks. Reviewed-by: Olaf Faaland <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Signed-off-by: Sanjeev Bagewadi <[email protected]> Closes #6530 Closes #7155
* Emit an error message before MMP suspends poolJohn L. Hammond2018-01-171-0/+5
| | | | | | | | | | | In mmp_thread(), emit an MMP specific error message before calling zio_suspend() so that the administrator will understand why the pool is being suspended. Reviewed-by: Olaf Faaland <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: John L. Hammond <[email protected]> Closes #7048
* Reimplement vdev_random_leaf and rename itOlaf Faaland2017-09-221-36/+26
| | | | | | | | | | | | | | | | | | | | | | | | | Rename it as mmp_random_leaf() since it is defined in mmp.c. The earlier implementation could end up spinning forever if a pool had a vdev marked writeable, none of whose children were writeable. It also did not guarantee that if a writeable leaf vdev existed, it would be found. Reimplement to recursively walk the device tree to select the leaf. It searches the entire tree, so that a return value of (NULL) indicates there were no usable leaves in the pool; all were either not writeable or had pending mmp writes. It still chooses the starting child randomly at each level of the tree, so if the pool's devices are healthy, the mmp writes go to random leaves with an even distribution. This was verified by testing using zfs_multihost_history enabled. Reviewed by: Thomas Caputi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #6631 Closes #6665
* Simplify threads, mutexs, cvs and rwlocksBrian Behlendorf2017-08-111-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Simplify threads, mutexs, cvs and rwlocks * Update the zk_thread_create() function to use the same trick as Illumos. Specifically, cast the new pthread_t to a void pointer and return that as the kthread_t *. This avoids the issues associated with managing a wrapper structure and is safe as long as the callers never attempt to dereference it. * Update all function prototypes passed to pthread_create() to match the expected prototype. We were getting away this with before since the function were explicitly cast. * Replaced direct zk_thread_create() calls with thread_create() for code consistency. All consumers of libzpool now use the proper wrappers. * The mutex_held() calls were converted to MUTEX_HELD(). * Removed all mutex_owner() calls and retired the interface. Instead use MUTEX_HELD() which provides the same information and allows the implementation details to be hidden. In this case the use of the pthread_equals() function. * The kthread_t, kmutex_t, krwlock_t, and krwlock_t types had any non essential fields removed. In the case of kthread_t and kcondvar_t they could be directly typedef'd to pthread_t and pthread_cond_t respectively. * Removed all extra ASSERTS from the thread, mutex, rwlock, and cv wrapper functions. In practice, pthreads already provides the vast majority of checks as long as we check the return code. Removing this code from our wrappers help readability. * Added TS_JOINABLE state flag to pass to request a joinable rather than detached thread. This isn't a standard thread_create() state but it's the least invasive way to pass this information and is only used by ztest. TEST_ZTEST_TIMEOUT=3600 Chunwei Chen <[email protected]> Reviewed-by: Tom Caputi <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #4547 Closes #5503 Closes #5523 Closes #6377 Closes #6495
* Add callback for zfs_multihost_intervalOlaf Faaland2017-07-251-1/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | Add a callback to wake all running mmp threads when zfs_multihost_interval is changed. This is necessary when the interval is changed from a very large value to a significantly lower one, while pools are imported that have the multihost property enabled. Without this commit, the mmp thread does not wake up and detect the new interval until after it has waited the old multihost interval time. A user monitoring mmp writes via the provided kstat would be led to believe that the changed setting did not work. Added a test in the ZTS under mmp to verify the new functionality is working. Added a test to ztest which starts and stops mmp threads, and calls into the code to signal sleeping mmp threads, to test for deadlocks or similar locking issues. Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #6387
* Release SCL_STATE in map_write_done()Olaf Faaland2017-07-251-5/+6
| | | | | | | | | | | | | | | | | The config lock must be held for the duration of the MMP write. Since the I/Os are executed via map_nowait(), the done function is the only place where we know the write has completed. Since SCL_STATE is taken as reader, overlapping I/Os do not create a deadlock. The refcount is simply increased when new I/Os are queued and decreased when I/Os complete. Test case added which exercises the probe IO call path to verify the fix and prevent a regression. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #6394
* Use correct macro for hz in mmp.cOlaf Faaland2017-07-241-1/+1
| | | | | | | | | | | | | | Commit 379ca9c Multi-modifier protection (MMP) used HZ to convert nanoseconds to ticks for use with cv_timedwait() and ddi_get_lbolt(). The correct macro is hz, which is defined within the SPL for kernel space, and within zfs_context.h for user space. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #6357 Closes #6360
* Fix coverity defects: CID 165755Giuseppe Di Natale2017-07-241-2/+2
| | | | | | | | | CID 165755: Division or modulo by zero (DIVIDE_BY_ZERO) Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Olaf Faaland <[email protected]> Signed-off-by: Giuseppe Di Natale <[email protected]> Closes #6352
* Multi-modifier protection (MMP)Olaf Faaland2017-07-131-0/+475
Add multihost=on|off pool property to control MMP. When enabled a new thread writes uberblocks to the last slot in each label, at a set frequency, to indicate to other hosts the pool is actively imported. These uberblocks are the last synced uberblock with an updated timestamp. Property defaults to off. During tryimport, find the "best" uberblock (newest txg and timestamp) repeatedly, checking for change in the found uberblock. Include the results of the activity test in the config returned by tryimport. These results are reported to user in "zpool import". Allow the user to control the period between MMP writes, and the duration of the activity test on import, via a new module parameter zfs_multihost_interval. The period is specified in milliseconds. The activity test duration is calculated from this value, and from the mmp_delay in the "best" uberblock found initially. Add a kstat interface to export statistics about Multiple Modifier Protection (MMP) updates. Include the last synced txg number, the timestamp, the delay since the last MMP update, the VDEV GUID, the VDEV label that received the last MMP update, and the VDEV path. Abbreviated output below. $ cat /proc/spl/kstat/zfs/mypool/multihost 31 0 0x01 10 880 105092382393521 105144180101111 txg timestamp mmp_delay vdev_guid vdev_label vdev_path 20468 261337 250274925 68396651780 3 /dev/sda 20468 261339 252023374 6267402363293 1 /dev/sdc 20468 261340 252000858 6698080955233 1 /dev/sdx 20468 261341 251980635 783892869810 2 /dev/sdy 20468 261342 253385953 8923255792467 3 /dev/sdd 20468 261344 253336622 042125143176 0 /dev/sdab 20468 261345 253310522 1200778101278 2 /dev/sde 20468 261346 253286429 0950576198362 2 /dev/sdt 20468 261347 253261545 96209817917 3 /dev/sds 20468 261349 253238188 8555725937673 3 /dev/sdb Add a new tunable zfs_multihost_history to specify the number of MMP updates to store history for. By default it is set to zero meaning that no MMP statistics are stored. When using ztest to generate activity, for automated tests of the MMP function, some test functions interfere with the test. For example, the pool is exported to run zdb and then imported again. Add a new ztest function, "-M", to alter ztest behavior to prevent this. Add new tests to verify the new functionality. Tests provided by Giuseppe Di Natale. Reviewed by: Matthew Ahrens <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Ned Bass <[email protected]> Reviewed-by: Andreas Dilger <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #745 Closes #6279