Commit Graph

1604 Commits

Author SHA1 Message Date
Paul Dagnelie 108a454a46
Add support for boot environment data to be stored in the label
Modern bootloaders leverage data stored in the root filesystem to 
enable some of their powerful features. GRUB specifically has a grubenv 
file which can store large amounts of configuration data that can be 
read and written at boot time and during normal operation. This allows 
sysadmins to configure useful features like automated failover after 
failed boot attempts. Unfortunately, due to the Copy-on-Write nature 
of ZFS, the standard behavior of these tools cannot handle writing to
ZFS files safely at boot time. We need an alternative way to store 
data that allows the bootloader to make changes to the data.

This work is very similar to work that was done on Illumos to enable 
similar functionality in the FreeBSD bootloader. This patch is different 
in that the data being stored is a raw grubenv file; this file can store 
arbitrary variables and values, and the scripting provided by grub is 
powerful enough that special structures are not required to implement 
advanced behavior.

We repurpose the second padding area in each label to store the grubenv 
file, protected by an embedded checksum. We add two ioctls to get and 
set this data, and libzfs_core and libzfs functions to access them more 
easily. There are no direct command line interfaces to these functions; 
these will be added directly to the bootloader utilities.

Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #10009
2020-05-07 09:36:33 -07:00
Ryan Moeller 639dfeb831
Update FreeBSD SPL atomics
Sync up with the following changes from FreeBSD:

ZFS: add emulation of atomic_swap_64 and atomic_load_64

Some 32-bit platforms do not provide 64-bit atomic operations that ZFS
requires, either in userland or at all.  We emulate those operations
for those platforms using a mutex.  That is not entirely correct and
it's very efficient.  Besides, the loads are plain loads, so torn
values are possible.

Nevertheless, the emulation seems to work for some definition of work.

This change adds atomic_swap_64, which is already used in ZFS code,
and atomic_load_64 that can be used to prevent torn reads.

Authored by: avg <avg@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd@3458e5d1e6

cleanup of illumos compatibility atomics

atomic_cas_32 is implemented using atomic_fcmpset_32 on all platforms.
Ditto for atomic_cas_64 and atomic_fcmpset_64 on platforms that have
it.  The only exception is sparc64 that provides MD atomic_cas_32 and
atomic_cas_64.
This is slightly inefficient as fcmpset reports whether the operation
updated the target and that information is not needed for cas.
Nevertheless, there is less code to maintain and to add for new
platforms.  Also, the operations are done inline now as opposed to
function calls before.

atomic_add_64_nv is implemented using atomic_fetchadd_64 on platforms
that provide it.

casptr, cas32, atomic_or_8, atomic_or_8_nv are completely removed as
they have no users.

atomic_mtx that is used to emulate 64-bit atomics on platforms that
lack them is defined only on those platforms.

As a result, platform specific opensolaris_atomic.S files have lost
most of their code.  The only exception is i386 where the
compat+contrib code provides 64-bit atomics for userland use.  That
code assumes availability of cmpxchg8b instruction.  FreeBSD does not
have that assumption for i386 userland and does not provide 64-bit
atomics.  Hopefully, this can and will be fixed.

Authored by: avg <avg@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd@e9642c209b

emulate illumos membar_producer with atomic_thread_fence_rel

membar_producer is supposed to be a store-store barrier.
Also, in the code that FreeBSD has ported from illumos membar_producer
is used only with regular stores to regular memory (with respect to
caching).

We do not have an MI primitive for the store-store barrier, so
atomic_thread_fence_rel is the closest we have as it provides
(load | store) -> store barrier.

Previously, membar_producer was an empty function call on all 32-bit
arm-s, 32-bit powerpc, riscv and all mips variants.  I think that it
was inadequate.
On other platforms, such as amd64, arm64, i386, powerpc64, sparc64,
membar_producer was implemented using stronger primitives than required
for a store-store barrier with respect to regular memory access.
For example, it used sfence on amd64 and lock-ed nop in i386 (despite
TSO).
On powerpc64 we now use recommended lwsync instead of eieio.
On sparc64 FreeBSD uses TSO mode.
On arm64/aarch64 we now use dmb sy instead of dmb ish.  Not sure if
this is an improvement, actually.

After this change we can drop opensolaris_atomic.S for aarch64, amd64,
powerpc64 and sparc64 as all required atomic operations have either
direct or light-weight mapping to FreeBSD native atomic operations.

Discussed with: kib
Authored by: avg <avg@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd@50cdda62fc

fix up r353340, don't assume that fcmpset has strong semantics

fcmpset can have two kinds of semantics, weak and strong.
For practical purposes, strong semantics means that if fcmpset fails
then the reported current value is always different from the expected
value.  Weak semantics means that the reported current value may be the
same as the expected value even though fcmpset failed.  That's a so
called "sporadic" failure.

I originally implemented atomic_cas expecting strong semantics, but
many platforms actually have weak one.

Reported by:    pkubaj (not confirmed if same issue)
Discussed with: kib, mjg
Authored by: avg <avg@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd@238787c74e

[PowerPC] [MIPS] Implement 32-bit kernel emulation of atomic64 operations

This is a lock-based emulation of 64-bit atomics for kernel use, split off
from an earlier patch by jhibbits.

This is needed to unblock future improvements that reduce the need for
locking on 64-bit platforms by using atomic updates.

The implementation allows for future integration with userland atomic64,
but as that implies going through sysarch for every use, the current
status quo of userland doing its own locking may be for the best.

Submitted by:   jhibbits (original patch), kevans (mips bits)
Reviewed by:    jhibbits, jeff, kevans
Authored by: bdragon <bdragon@FreeBSD.org>
Differential Revision:  https://reviews.freebsd.org/D22976
FreeBSD-commit: freebsd/freebsd@db39dab3a8

Remove sparc64 kernel support

Remove all sparc64 specific files
Remove all sparc64 ifdefs
Removee indireeect sparc64 ifdefs

Authored by: imp <imp@FreeBSD.org>
FreeBSD-commit: freebsd/freebsd@48b94864c5

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Ported-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10250
2020-05-04 15:07:04 -07:00
Paul B. Henson a1af567bb6 OpenZFS 742 - Resurrect the ZFS "aclmode" property OpenZFS 664 - Umask masking "deny" ACL entries OpenZFS 279 - Bug in the new ACL (post-PSARC/2010/029) semantics
Porting notes:
* Updated zfs_acl_chmod to take 'boolean_t isdir' as first parameter
  rather than 'zfsvfs_t *zfsvfs'
* zfs man pages changes mixed between zfs and new zfsprops man pages

Reviewed by: Aram Hvrneanu <aram@nexenta.com>
Reviewed by: Gordon Ross <gwr@nexenta.com>
Reviewed by: Robert Gordon <rbg@openrbg.com>
Reviewed by: Mark.Maybee@oracle.com
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@nexenta.com>
Ported-by: Paul B. Henson <henson@acm.org>

OpenZFS-issue: https://www.illumos.org/issues/742
OpenZFS-issue: https://www.illumos.org/issues/664
OpenZFS-issue: https://www.illumos.org/issues/279
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/a3c49ce110
Closes #10266
2020-04-30 11:22:45 -07:00
Jason King c14ca1456e
Support custom URI schemes for the keylocation property
Every platform has their own preferred methods for implementing URI 
schemes beyond the currently supported file scheme (e.g. 'https' on 
FreeBSD would likely use libfetch, while Linux distros and illumos
would probably use libcurl, etc). It would be helpful if libzfs can 
be extended to support additional schemes in a simple manner.

A table of (scheme, handler_function) pairs is added to libzfs_crypto.c, 
and the existing functions in libzfs_crypto.c so that when the key 
format is ZFS_KEYFORMAT_URI, the scheme from the URI string is 
extracted, and a matching handler it located in the aforementioned 
table (returning an error if no matching handler is found). The handler 
function is then invoked to retrieve the key material (in the format 
specified by the keyformat property) and the key is loaded or the 
handler can return an error to abort the key loading process.

Reviewed by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jason King <jason.king@joyent.com>
Closes #10218
2020-04-28 10:55:18 -07:00
Matthew Ahrens 196bee4cfd
Remove deduplicated send/receive code
Deduplicated send streams (i.e. `zfs send -D` and `zfs receive` of such
streams) are deprecated.  Deduplicated send streams can be received by
first converting them to non-deduplicated with the `zstream redup`
command.

This commit removes the code for sending and receiving deduplicated send
streams.  `zfs send -D` will now print a warning, ignore the `-D` flag,
and generate a regular (non-deduplicated) send stream.  `zfs receive` of
a deduplicated send stream will print an error message and fail.

The resulting code simplification (especially in the kernel's support
for receiving dedup streams) should help enable future performance
enhancements.

Several new tests are added which leverage `zstream redup`.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Issue #7887
Issue #10117
Issue #10156
Closes #10212
2020-04-23 10:06:57 -07:00
Matthew Ahrens 32d805c3e2
Use a struct to organize metaslab-group-allocator fields
Each metaslab group (of which there is one per top-level vdev) has
several (4, by default) "metaslab group allocators".  Each "allocator"
has its own metaslab that it prefers to allocate from (the "primary"
allocator), and each can perform allocations concurrently with the other
allocators.  In addition to the primary metaslab, there are several
other fields that need to be tracked separately for each allocator.
These are currently stored as several arrays in the metaslab_group_t,
each array indexed by allocator number.

This change organizes all the metaslab-group-allocator-specific fields
into a new struct, metaslab_group_allocator_t.  The metaslab_group_t now
needs only one array indexed by the allocator number - which contains
the metaslab_group_allocator_t's.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10213
2020-04-22 10:26:56 -07:00
Matthew Ahrens 1f043c8be1
Fix zfs send progress reporting
The progress of a send is supposed to be reported by `zfs send -v`, but
it is not.  This works by creating a new user thread (with
pthread_create()) which does ZFS_IOC_SEND_PROGRESS ioctls to check how
much progress has been made.  This IOCTL finds the specified send (since
there may be multiple concurrent sends in the system).  The IOCTL also
checks that the specified send was started by the current process.

On Linux, different threads of the same process are represented as
different `struct task_struct`s (and, confusingly, have different
PID's).  To check if if two threads are in the same process, we need to
check if they have the same `struct task_struct:group_leader`.

We used to to this correctly, but it was inadvertently changed by
30af21b025 (Redacted Send) to simply check if the current
`struct task_struct` is the one that started the send.

This commit changes the code back to checking if the send was started by
a `struct task_struct` with the same `group_leader` as the calling
thread.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Chris Wedgwood <cw@f00f.org>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10215 
Closes #10216
2020-04-20 10:12:48 -07:00
Matthew Macy c614fd6e12
Use new FreeBSD API to largely eliminate object locking
Propagate changes in HEAD that mostly eliminate object locking.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10205
2020-04-17 09:30:26 -07:00
Ryan Moeller a7929f3137
Update FreeBSD tunables
Remove some obsolete legacy compat, rename some misnamed, and add some
missing tunables for FreeBSD.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10203
2020-04-15 11:14:47 -07:00
Matthew Macy 9f0a21e641
Add FreeBSD support to OpenZFS
Add the FreeBSD platform code to the OpenZFS repository.  As of this
commit the source can be compiled and tested on FreeBSD 11 and 12.
Subsequent commits are now required to compile on FreeBSD and Linux.
Additionally, they must pass the ZFS Test Suite on FreeBSD which is
being run by the CI.  As of this commit 1230 tests pass on FreeBSD
and there are no unexpected failures.

Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #898 
Closes #8987
2020-04-14 11:36:28 -07:00
George Amanakis 77f6826b83
Persistent L2ARC
This commit makes the L2ARC persistent across reboots. We implement
a light-weight persistent L2ARC metadata structure that allows L2ARC
contents to be recovered after a reboot. This significantly eases the
impact a reboot has on read performance on systems with large caches.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Saso Kiselkov <skiselkov@gmail.com>
Co-authored-by: Jorgen Lundman <lundman@lundman.net>
Co-authored-by: George Amanakis <gamanakis@gmail.com>
Ported-by: Yuxuan Shui <yshuiv7@gmail.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #925 
Closes #1823 
Closes #2672 
Closes #3744 
Closes #9582
2020-04-10 10:33:35 -07:00
Ryan Moeller 36a6e2335c
Don't ignore zfs_arc_max below allmem/32
Set arc_c_min before arc_c_max so that when zfs_arc_min is set lower
than the default allmem/32 zfs_arc_max can also be set lower.

Add warning messages when tunables are being ignored.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10157
Closes #10158
2020-04-09 15:39:48 -07:00
Matthew Macy 8b27e08ed8
Add separate field for indicating that spa is in middle of split
By default it's not possible to open a device already owned by an
active vdev. It's necessary to make an exception to this for vdev
split. The FreeBSD platform code will make an exception if
spa_is splitting is set to to true.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10178
2020-04-09 09:59:31 -07:00
Brian Behlendorf 68dde63d13
Linux 5.7 compat: blk_alloc_queue()
Commit https://github.com/torvalds/linux/commit/3d745ea5 simplified
the blk_alloc_queue() interface by updating it to take the request
queue as an argument.  Add a wrapper function which accepts the new
arguments and internally uses the available interfaces.

Other minor changes include increasing the Linux-Maximum to 5.6 now
that 5.6 has been released.  It was not bumped to 5.7 because this
release has not yet been finalized and is still subject to change.

Added local 'struct zvol_state_os *zso' variable to zvol_alloc.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10181 
Closes #10187
2020-04-09 09:16:46 -07:00
Ryan Moeller 7e3df9db12
Finish refactoring for ZFS_MODULE_PARAM_CALL
Linux and FreeBSD have different parameters for tunable proc handler.
This has prevented FreeBSD from implementing the ZFS_MODULE_PARAM_CALL
macro.

To complete the sharing of ZFS_MODULE_PARAM_CALL declarations, create
per-platform definitions of the parameter list, ZFS_MODULE_PARAM_ARGS.

With the declarations wired up we discovered an incorrect scope prefix
for spa_slop_shift, so this is now fixed.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10179
2020-04-07 10:06:22 -07:00
Paul Dagnelie 5a42ef04fd
Add 'zfs wait' command
Add a mechanism to wait for delete queue to drain.

When doing redacted send/recv, many workflows involve deleting files 
that contain sensitive data. Because of the way zfs handles file 
deletions, snapshots taken quickly after a rm operation can sometimes 
still contain the file in question, especially if the file is very 
large. This can result in issues for redacted send/recv users who 
expect the deleted files to be redacted in the send streams, and not 
appear in their clones.

This change duplicates much of the zpool wait related logic into a 
zfs wait command, which can be used to wait until the internal
deleteq has been drained.  Additional wait activities may be added 
in the future. 

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #9707
2020-04-01 10:02:06 -07:00
Ryan Moeller 9a51738b60
Let default arc_c_max be platform dependent
Linux changed the default max ARC size to 1/2 of physical memory to
deal with shortcomings of the Linux SLUB allocator.  Other platforms
do not require the same logic.

Implement an arc_default_max() function to determine a default max ARC
size in platform code.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10155
2020-03-27 09:14:46 -07:00
Matthew Ahrens 3f38797338
Compile cityhash code into libzfs
Make the cityhash code compile into libzfs, in preparation for the new
"zstream" command.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10152
2020-03-27 09:11:22 -07:00
Matthew Ahrens 652bdc9b0e
Deprecate deduplicated send streams
Dedup send can only deduplicate over the set of blocks in the send
command being invoked, and it does not take advantage of the dedup table
to do so. This is a very common misconception among not only users, but
developers, and makes the feature seem more useful than it is. As a
result, many users are using the feature but not getting any benefit
from it.

Dedup send requires a nontrivial expenditure of memory and CPU to
operate, especially if the dataset(s) being sent is (are) not already
using a dedup-strength checksum.

Dedup send adds developer burden. It expands the test matrix when
developing new features, causing bugs in released code, and delaying
development efforts by forcing more testing to be done.

As a result, we are deprecating the use of `zfs send -D` and receiving
of such streams.  This change adds a warning to the man page, and also
prints the warning whenever dedup send or receive are used.

In a future release, we plan to:
1. remove the kernel code for generating deduplicated streams
2. make `zfs send -D` generate regular, non-deduplicated streams
3. remove the kernel code for receiving deduplicated streams
4. make `zfs receive` of deduplicated streams process them in userland
   to "re-duplicate" them, so that they can still be received.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #7887 
Closes #10117
2020-03-18 13:31:10 -07:00
Paul Dagnelie 7145123b0a
Separate warning for incomplete and corrupt streams
This change adds a separate return code to zfs_ioc_recv that is used 
for incomplete streams, in addition to the existing return code for 
streams that contain corruption.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #10122
2020-03-17 10:30:33 -07:00
Mariusz Zaborski a57d3d45d6
Add option for forcible unmounting dataset while receiving snapshot.
Currently when the dataset is in use we can't receive snapshots.

    zfs send test/1@asd | zfs recv -FM test/2
    cannot unmount '/test/2': Device busy

This commits add option 'M' which attempts to forcibly unmount the
dataset.  Thanks to this we can enforce receiving snapshots in a
single step.

Note that this functionality is not supported on Linux because the
VFS will prevent active mounted filesystems from being unmounted,
even with the force option.  This is the intended VFS behavior.

Test cases were added to verify the expected behavior based on
the platform.

Discussed-with: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allanjude@freebsd.org>
External-issue: https://reviews.freebsd.org/D22306
Closes #9904
2020-03-17 10:08:32 -07:00
Matthew Ahrens 0fdd6106bb
dmu_objset_from_ds must be called with dp_config_rwlock held
The normal lock order is that the dp_config_rwlock must be held before
the ds_opening_lock.  For example, dmu_objset_hold() does this.
However, dmu_objset_open_impl() is called with the ds_opening_lock held,
and if the dp_config_rwlock is not already held, it will attempt to
acquire it.  This may lead to deadlock, since the lock order is
reversed.

Looking at all the callers of dmu_objset_open_impl() (which is
principally the callers of dmu_objset_from_ds()), almost all callers
already have the dp_config_rwlock.  However, there are a few places in
the send and receive code paths that do not.  For example:
dsl_crypto_populate_key_nvlist, send_cb, dmu_recv_stream,
receive_write_byref, redact_traverse_thread.

This commit resolves the problem by requiring all callers ot
dmu_objset_from_ds() to hold the dp_config_rwlock.  In most cases, the
code has been restructured such that we call dmu_objset_from_ds()
earlier on in the send and receive processes, when we already have the
dp_config_rwlock, and save the objset_t until we need it in the middle
of the send or receive (similar to what we already do with the
dsl_dataset_t).  Thus we do not need to acquire the dp_config_rwlock in
many new places.

I also cleaned up code in dmu_redact_snap() and send_traverse_thread().

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #9662
Closes #10115
2020-03-12 10:55:02 -07:00
John Poduska e6b28efccc
Prevent race condition in dnode_dest (#10101)
dnode_special_close() waits for the refcount of dn_holds to go to zero
without holding the dn_mtx. dnode_rele_and_unlock() does the final
remove to dn_holds with dn_mtx being held:

	refs = zfs_refcount_remove(&dn->dn_holds, tag);
	mutex_exit(&dn->dn_mtx);

So, there is a race condition after the remove until dn_mtx is
dropped. During that time, dnode_destroy() can get called, which ends
up in dnode_dest() calling mutex_destroy() and a panic since the lock
is still held.

This change adds a condvar to wait for the final dnode_rele_and_unlock()
to release the dn_mtx before calling dnode_destroy().

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: John Poduska <jpoduska@datto.com>
Closes #7814
Closes #10101
2020-03-12 10:25:56 -07:00
Matthew Ahrens 1dc32a67e9
Improve zfs send performance by bypassing the ARC
When doing a zfs send on a dataset with small recordsize (e.g. 8K),
performance is dominated by the per-block overheads.  This is especially
true with `zfs send --compressed`, which further reduces the amount of
data sent, for the same number of blocks.  Several threads are involved,
but the limiting factor is the `send_prefetch` thread, which is 100% on
CPU.

The main job of the `send_prefetch` thread is to issue zio's for the
data that will be needed by the main thread.  It does this by calling
`arc_read(ARC_FLAG_PREFETCH)`.  This has an immediate cost of creating
an arc_hdr, which takes around 14% of one CPU.  It also induces later
costs by other threads:

 * Since the data was only prefetched, dmu_send()->dmu_dump_write() will
   need to call arc_read() again to get the data.  This will have to
   look up the arc_hdr in the hash table and copy the data from the
   scatter ABD in the arc_hdr to a linear ABD in arc_buf.  This takes
   27% of one CPU.

 * dmu_dump_write() needs to arc_buf_destroy()  This takes 11% of one
   CPU.

 * arc_adjust() will need to evict this arc_hdr, taking about 50% of one
   CPU.

All of these costs can be avoided by bypassing the ARC if the data is
not already cached.  This commit changes `zfs send` to check for the
data in the ARC, and if it is not found then we directly call
`zio_read()`, reading the data into a linear ABD which is used by
dmu_dump_write() directly.

The performance improvement is best expressed in terms of how many
blocks can be processed by `zfs send` in one second.  This change
increases the metric by 50%, from ~100,000 to ~150,000.  When the amount
of data per block is small (e.g. 2KB), there is a corresponding
reduction in the elapsed time of `zfs send >/dev/null` (from 86 minutes
to 58 minutes in this test case).

In addition to improving the performance of `zfs send`, this change
makes `zfs send` not pollute the ARC cache.  In most cases the data will
not be reused, so this allows us to keep caching useful data in the MRU
(hit-once) part of the ARC.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10067
2020-03-10 10:51:04 -07:00
Brian Behlendorf 2288d41968
Add trim support to zpool wait
Manual trims fall into the category of long-running pool activities
which people might want to wait synchronously for. This change adds
support to 'zpool wait' for waiting for manual trim operations to
complete. It also adds a '-w' flag to 'zpool trim' which can be used to
turn 'zpool trim' into a synchronous operation.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
Closes #10071
2020-03-04 15:07:11 -08:00
Matthew Ahrens b3212d2fa6
Improve performance of zio_taskq_member
__zio_execute() calls zio_taskq_member() to determine if we are running
in a zio interrupt taskq, in which case we may need to switch to
processing this zio in a zio issue taskq.  The call to
zio_taskq_member() can become a performance bottleneck when we are
processing a high rate of zio's.

zio_taskq_member() calls taskq_member() on each of the zio interrupt
taskqs, of which there are 21.  This is slow because each call to
taskq_member() does tsd_get(taskq_tsd), which on Linux is relatively
slow.

This commit improves the performance of zio_taskq_member() by having it
cache the value of tsd_get(taskq_tsd), reducing the number of those
calls to 1/21th of the current behavior.

In a test case running `zfs send -c >/dev/null` of a filesystem with
small blocks (average 2.5KB/block), zio_taskq_member() was using 6.7% of
one CPU, and with this change it is reduced to 1.3%.  Overall time to
perform the `zfs send` reduced by 10% (~150,000 block/sec to ~165,000
blocks/sec).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10070
2020-03-03 10:29:38 -08:00
Ryan Moeller 9bb907bc3f
Make spa_history_zone platform-dependent in kernel
This function should only return "linux" on Linux.

Move the kernel part of the function out of common code.
Fix the tests for FreeBSD.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10079
2020-03-02 09:43:30 -08:00
Matthew Macy ae9f92f6f3
Re-share zfsdev_getminor and zfs_onexit_fd_hold
By adding a zfs_file_private accessor to the common
interfaces and some extensions to FreeBSD platform
code it is now possible to share the implementations
for the aforementioned functions.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10073
2020-02-28 14:50:32 -08:00
Brian Behlendorf 2c3a83701d Linux 5.6 compat: time_t
As part of the Linux kernel's y2038 changes the time_t type has been
fully retired.  Callers are now required to use the time64_t type.

Rather than move to the new type, I've removed the few remaining
places where a time_t is used in the kernel code.  They've been
replaced with a uint64_t which is already how ZFS internally
handled these values.

Going forward we should work towards updating the remaining user
space time_t consumers to the 64-bit interfaces.

Reviewed-by: Matthew Macy <mmacy@freebsd.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10052
Closes #10064
2020-02-27 09:31:02 -08:00
Brian Behlendorf ff5587d651 Linux 5.6 compat: ktime_get_raw_ts64()
The getrawmonotonic() and getrawmonotonic64() interfaces have been
fully retired.  Update gethrtime() to use the replacement interface
ktime_get_raw_ts64() which was introduced in the 4.18 kernel.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10052
Closes #10064
2020-02-27 09:30:45 -08:00
Matthew Macy 28caa74b19
Refactor dnode dirty context from dbuf_dirty
* Add dedicated donde_set_dirtyctx routine.
* Add empty dirty record on destroy assertion.
* Make much more extensive use of the SET_ERROR macro.

Reviewed-by: Will Andrews <wca@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9924
2020-02-26 16:09:17 -08:00
Dirkjan Bussink 327000ce04
Remove zfs_getattr and convoff dead code
The `convoff` function is called only in one code path in `zfs_space`.
Each caller of `zfs_space` is called with a `flock64_t` that has
`l_whence` set to `SEEK_SET`. This means that `convoff` always results
in a no-op as the `bfp` parameter has `l_whence` set to `SEEK_SET` and
`int whence` is `SEEK_SET` as well.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by:  Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
Closes #10006
2020-02-24 15:38:22 -08:00
Ryan Moeller 5f087dda78
Enable zpool events tunables and tests on FreeBSD
We have have made the necessary changes in our module code to expose
zevents through both devd and the zpool events ioctl. Now the tunables
can be exposed and zpool events tests can be enabled on both platforms.

A few minor tweaks to the tests were needed to accommodate the way wc
formats output on FreeBSD.

zed remains to be ported.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10008
2020-02-18 11:22:56 -08:00
Matthew Macy 8b3547a481
Factor out some dbuf subroutines and add state change tracing
Create dedicated dbuf_read_hole and dbuf_read_bonus.
Additionally, add a dtrace probe to allow state change tracing.

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Will Andrews <wca@FreeBSD.org>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Authored-by: Will Andrews <wca@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9923
2020-02-18 11:21:37 -08:00
Richard Laager f244846462
Prefer org.openzfs for features and properties
Moving forward, we wish to use org.openzfs (no dash) rather than
org.open-zfs or org.zfsonlinux for feature GUIDs and property names.
The existing feature GUIDs cannot be changed.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #10003
2020-02-18 09:36:50 -08:00
Jason King 13b5a4d5c0
Support setting user properties in a channel program
This adds support for setting user properties in a
zfs channel program by adding 'zfs.sync.set_prop'
and 'zfs.check.set_prop' to the ZFS LUA API.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Co-authored-by: Sara Hartse <sara.hartse@delphix.com>
Contributions-by: Jason King <jason.king@joyent.com>
Signed-off-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Jason King <jason.king@joyent.com>
Closes #9950
2020-02-14 13:41:42 -08:00
Matthew Ahrens 4fe3a842bb
Remove limit on number of async zio_frees of non-dedup blocks
The module parameter zfs_async_block_max_blocks limits the number of
blocks that can be freed by the background freeing of filesystems and
snapshots (from "zfs destroy"), in one TXG.  This is useful when freeing
dedup blocks, becuase each zio_free() of a dedup block can require an
i/o to read the relevant part of the dedup table (DDT), and will also
dirty that block.

zfs_async_block_max_blocks is set to 100,000 by default.  For the more
typical case where dedup is not used, this can have a negative
performance impact on the rate of background freeing (from "zfs
destroy").  For example, with recordsize=8k, and TXG's syncing once
every 5 seconds, we can free only 160MB of data per second, which may be
much less than the rate we can write data.

This change increases zfs_async_block_max_blocks to be unlimited by
default.  To address the dedup freeing issue, a new tunable is
introduced, zfs_max_async_dedup_frees, which limits the number of
zio_free()'s of dedup blocks done by background destroys, per txg.  The
default is 100,000 free's (same as the old zfs_async_block_max_blocks
default).

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10000
2020-02-14 08:39:46 -08:00
Alexander Motin 465e4e795e
Remove duplicate dbufs accounting
Since AVL already has embedded element counter, use dn_dbufs_count
only for dbufs not counted there (bonus buffers) and just add them.
This removes two atomics per dbuf life cycle.

According to profiler it reduces time spent by dbuf_destroy() inside
bottlenecked dbuf_evict_thread() from 13.36% to 9.20% of the core.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #9949
2020-02-13 11:20:42 -08:00
Christian Schwarz 948f0c4419 zcp: add zfs.sync.bookmark
Add support for bookmark creation and cloning.

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Christian Schwarz <me@cschwarz.com>
Closes #9571
2020-02-11 13:19:17 -08:00
Christian Schwarz a73f361fdb Implement bookmark copying
This feature allows copying existing bookmarks using

    zfs bookmark fs#target fs#newbookmark

There are some niche use cases for such functionality,
e.g. when using bookmarks as markers for replication progress.

Copying redaction bookmarks produces a normal bookmark that
cannot be used for redacted send (we are not duplicating
the redaction object).

ZCP support for bookmarking (both creation and copying) will be
implemented in a separate patch based on this work.

Overview:

- Terminology:
    - source = existing snapshot or bookmark
    - new/bmark = new bookmark
- Implement bookmark copying in `dsl_bookmark.c`
  - create new bookmark node
  - copy source's `zbn_phys` to new's `zbn_phys`
  - zero-out redaction object id in copy
- Extend existing bookmark ioctl nvlist schema to accept
  bookmarks as sources
  - => `dsl_bookmark_create_nvl_validate` is authoritative
- use `dsl_dataset_is_before` check for both snapshot
  and bookmark sources
- Adjust CLI
  - refactor shortname expansion logic in `zfs_do_bookmark`
- Update man pages
  - warn about redaction bookmark handling
- Add test cases
  - CLI
  - pyyzfs libzfs_core bindings

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Christian Schwarz <me@cschwarz.com>
Closes #9571
2020-02-11 13:19:12 -08:00
Paul Zuchowski bc67cba7c0
Fix zdb -R with 'b' flag
zdb -R :b fails due to the indirect block being compressed,
and the 'b' and 'd' flag not working in tandem when specified.
Fix the flag parsing code and create a zfs test for zdb -R
block display.  Also fix the zio flags where the dotted notation
for the vdev portion of DVA (i.e. 0.0:offset:length) fails.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9640
Closes #9729
2020-02-10 14:00:05 -08:00
Ryan Moeller 57940b435c
Share some code for spa deadman tunables
We need to do the same thing to update all spas on any OS for these
tunables, so let's share the code.

While here let's match the types of the literals initializing the
variables with the type of the variable.

Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #9964
2020-02-10 13:11:30 -08:00
Attila Fülöp 31b160f0a6
ICP: Improve AES-GCM performance
Currently SIMD accelerated AES-GCM performance is limited by two
factors:

a. The need to disable preemption and interrupts and save the FPU
state before using it and to do the reverse when done. Due to the
way the code is organized (see (b) below) we have to pay this price
twice for each 16 byte GCM block processed.

b. Most processing is done in C, operating on single GCM blocks.
The use of SIMD instructions is limited to the AES encryption of the
counter block (AES-NI) and the Galois multiplication (PCLMULQDQ).
This leads to the FPU not being fully utilized for crypto
operations.

To solve (a) we do crypto processing in larger chunks while owning
the FPU. An `icp_gcm_avx_chunk_size` module parameter was introduced
to make this chunk size tweakable. It defaults to 32 KiB. This step
alone roughly doubles performance. (b) is tackled by porting and
using the highly optimized openssl AES-GCM assembler routines, which
do all the processing (CTR, AES, GMULT) in a single routine. Both
steps together result in up to 32x reduction of the time spend in
the en/decryption routines, leading up to approximately 12x
throughput increase for large (128 KiB) blocks.

Lastly, this commit changes the default encryption algorithm from
AES-CCM to AES-GCM when setting the `encryption=on` property.

Reviewed-By: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-By: Jason King <jason.king@joyent.com>
Reviewed-By: Tom Caputi <tcaputi@datto.com>
Reviewed-By: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes #9749
2020-02-10 12:59:50 -08:00
Brian Behlendorf 795699a6cc Linux 5.6 compat: timestamp_truncate()
The timestamp_truncate() function was added, it replaces the existing
timespec64_trunc() function.  This change renames our wrapper function
to be consistent with the upstream name and updates the compatibility
code for older kernels accordingly.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9956
Closes #9961
2020-02-07 11:04:32 -08:00
Brian Behlendorf 0dd7364853 Linux 5.6 compat: struct proc_ops
The proc_ops structure was introduced to replace the use of of the
file_operations structure when registering proc handlers.  This
change creates a new kstat_proc_op_t typedef for compatibility
which can be used to pass around the correct structure.

This change additionally adds the 'const' keyword to all of the
existing proc operations structures.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9961
2020-02-07 11:03:53 -08:00
Alexander Motin e0ce98d57c
Reduce number of atomic_add() calls in aggsum
Previous code used 4 atomics to do aggsum_flush_bucket() and 2 more to
re-borrow after the flush.  But since asc_borrowed and asc_delta are
accessed only while holding asc_lock, it makes no any sense to modify
as_lower_bound and as_upper_bound in multiple steps.  Instead of that
the new code uses only 2 atomics in all the cases, one per as_*_bound
variable.  I think even that is overkill, simple atomic store and
load could be used here, since all modifications are done under the
as_lock, but there are no such primitives in ZFS code now.

While there, make borrow code consider previous borrow value, so that
on mixed request patterns reduce chance of needing to borrow again if
much larger request follows tiny one that needed borrow.

Also reduce as_numbuckets from uint64_t to u_int.  It makes no sense
to use so large division operation on every aggsum_add().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #9930
2020-02-06 13:21:06 -08:00
Alexander Motin cbd8f5b759
Few microoptimizations to dbuf layer
Move db_link into the same cache line as db_blkid and db_level.
It allows significantly reduce avl_add() time in dbuf_create() on
systems with large RAM and huge number of dbufs per dnode.

Avoid few accesses to dbuf_caches[].size, which is highly congested
under high IOPS and never stays in cache for a long time.  Use local
value we are receiving from zfs_refcount_add_many() any way.

Remove cache_size_bytes_max bump from dbuf_evict_one().  I don't see
a point to do it on dbuf eviction after we done it on insertion in
dbuf_rele_and_unlock().

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #9931
2020-02-05 11:08:44 -08:00
Matthew Macy cccbed9f98
Convert dbuf dirty record record list to a list_t
Additionally pull in state machine comments about
upcoming async cow work.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9902
2020-02-05 11:07:19 -08:00
Ryan Moeller 8c4987c489
Restore aclmode and remove acltype on FreeBSD
This replaces the placeholder ZFS_PROP_PRIVATE with ZFS_PROP_ACLMODE,
matching what is done in the NFSv4 ACLs PR (#9709).

On FreeBSD we hide ZFS_PROP_ACLTYPE, while on Linux we hide
ZFS_PROP_ACLMODE.

The tests already assume this arrangement.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #9913
2020-02-04 08:40:07 -08:00
Matthew Ahrens ec21397127
async zvol minor node creation interferes with receive
When we finish a zfs receive, dmu_recv_end_sync() calls
zvol_create_minors(async=TRUE).  This kicks off some other threads that
create the minor device nodes (in /dev/zvol/poolname/...).  These async
threads call zvol_prefetch_minors_impl() and zvol_create_minor(), which
both call dmu_objset_own(), which puts a "long hold" on the dataset.
Since the zvol minor node creation is asynchronous, this can happen
after the `ZFS_IOC_RECV[_NEW]` ioctl and `zfs receive` process have
completed.

After the first receive ioctl has completed, userland may attempt to do
another receive into the same dataset (e.g. the next incremental
stream).  This second receive and the asynchronous minor node creation
can interfere with one another in several different ways, because they
both require exclusive access to the dataset:

1. When the second receive is finishing up, dmu_recv_end_check() does
dsl_dataset_handoff_check(), which can fail with EBUSY if the async
minor node creation already has a "long hold" on this dataset.  This
causes the 2nd receive to fail.

2. The async udev rule can fail if zvol_id and/or systemd-udevd try to
open the device while the the second receive's async attempt at minor
node creation owns the dataset (via zvol_prefetch_minors_impl).  This
causes the minor node (/dev/zd*) to exist, but the udev-generated
/dev/zvol/... to not exist.

3. The async minor node creation can silently fail with EBUSY if the
first receive's zvol_create_minor() trys to own the dataset while the
second receive's zvol_prefetch_minors_impl already owns the dataset.

To address these problems, this change synchronously creates the minor
node.  To avoid the lock ordering problems that the asynchrony was
introduced to fix (see #3681), we create the minor nodes from open
context, with no locks held, rather than from syncing contex as was
originally done.

Implementation notes:

We generally do not need to traverse children or prefetch anything (e.g.
when running the recv, snapshot, create, or clone subcommands of zfs).
We only need recursion when importing/opening a pool and when loading
encryption keys.  The existing recursive, asynchronous, prefetching code
is preserved for use in these cases.

Channel programs may need to create zvol minor nodes, when creating a
snapshot of a zvol with the snapdev property set.  We figure out what
snapshots are created when running the LUA program in syncing context.
In this case we need to remember what snapshots were created, and then
try to create their minor nodes from open context, after the LUA code
has completed.

There are additional zvol use cases that asynchronously own the dataset,
which can cause similar problems.  E.g. changing the volmode or snapdev
properties.  These are less problematic because they are not recursive
and don't touch datasets that are not involved in the operation, there
is still potential for interference with subsequent operations.  In the
future, these cases should be similarly converted to create the zvol
minor node synchronously from open context.

The async tasks of removing and renaming minors do not own the objset,
so they do not have this problem.  However, it may make sense to also
convert these operations to happen synchronously from open context, in
the future.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-65948
Closes #7863
Closes #9885
2020-02-03 09:33:14 -08:00