The zfs_fsync, zfs_read, and zfs_write function are almost identical
between Linux and FreeBSD. With a little refactoring they can be
moved to the common code which is what is done by this commit.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#11078
Move platform specific Linux source under module/os/linux/
and update the build system accordingly. Additional code
restructuring will follow to make the common code fully
portable.
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Macy <mmacy@FreeBSD.org>
Closes#9206
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes#9240
We should only call zil_remove_async when an object is removed. However,
in current implementation, it is called whenever TX_REMOVE is called. In
the case of hardlinked file, every unlink will generate TX_REMOVE and
causing operations to be dropped even when the object is not removed.
We fix this by only calling zil_remove_async when the file is fully
unlinked.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes#8769Closes#9061
Given znode_t is an in-core structure, it's more readable to have
them as boolean. Also co-locate existing boolean fields with them
for space efficiency (expecting 8 booleans to be packed/aligned).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#9092
In zfs_write() and dmu_tx_hold_sa(), we can use dmu_tx_hold_*_by_dnode()
instead of dmu_tx_hold_*(), since we already have a dbuf from the target
dnode in hand. This eliminates some calls to dnode_hold(), which can be
expensive. This is especially impactful if several threads are
accessing objects that are in the same block of dnodes, because they
will contend for that dbuf's lock.
We are seeing 10-20% performance wins for the sequential_writes tests in
the performance test suite, when doing >=128K writes to files with
recordsize=8K.
This also removes some unnecessary casts that are in the area.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#9081
These aren't tunable; illumos has this comment fixed in
"3742 zfs comments need cleaner, more consistent style",
so sync with that.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#9052
These descriptions are not uptodate with the code.
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#8767
wait_on_page_writeback() was made GPL only in torvalds/linux@19343b5bdd.
Directly call wait_on_page_bit() without using wait_on_page_writeback()
interface, given zfs_putpage() is the only caller for now.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes#8794
Given how zfs_getattr() is implemented, zfs_getattr_fast() (used by
->getattr() of zpl inodes) also needs to consider an additional link
count if "snapdir" property is set to "visible".
Without this, # of directories in root inode of each dataset doesn't
match the link count when snapdir is visible.
Reviewed-by: Richard Yao <ryao@gentoo.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes#8727
Commit 98bb45e resolved a deadlock which could occur when
handling a page fault in zfs_write(). This change added
the uio_fault_disable field to the uio structure but failed
to initialize it to B_FALSE. This uninitialized field would
cause uiomove_iov() to call __copy_from_user_inatomic()
instead of copy_from_user() resulting in unexpected EFAULTs.
Resolve the issue by fully initializing the uio, and clearing
the uio_fault_disable flags after it's used in zfs_write().
Additionally, reorder the uio_t field assignments to match
the order the fields are declared in the structure.
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8640Closes#8719
Use either SEEK_* or 0,1,2..., but not both.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#8656
These aren't unused.
`flag` in zfs_create() also isn't to indicate large file.
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#8635
The bulk[] array index, count, must be reset per-iteration in order to
not overwrite the stack.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#8072Closes#8597Closes#8601
ZFS supports O_RSYNC for read operations and when specified will ensure
the same level of data integrity that O_DSYNC and O_SYNC provides for
writes. O_RSYNC by itself has no effect so it must be combined with
either O_DSYNC or O_SYNC. However, many platforms don't support O_RSYNC
and have mapped O_SYNC to mean O_RSYNC within ZFS. This is incorrect
and causes unnecessary calls to zil_commit. Only platforms which
support O_RSYNC should implement the zil_commit functionality in the
read code path.
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Wilson <george.wilson@delphix.com>
Closes#8523
Currently, the functions dbuf_prefetch_indirect_done() and
dmu_assign_arcbuf_by_dnode() assume that dbuf_hold_level() cannot
fail. In the event of an error the former will cause a NULL pointer
dereference and the later will trigger a VERIFY. This patch adds
error handling to these functions and their callers where necessary.
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#8291
As a result of the changes made in 8585, it's possible for an excessive
amount of vdev flush commands to be issued under some workloads.
Specifically, when the workload consists of mostly async write activity,
interspersed with some sync write and/or fsync activity, we can end up
issuing more flush commands to the underlying storage than is actually
necessary. As a result of these flush commands, the write latency and
overall throughput of the pool can be poorly impacted (latency
increases, throughput decreases).
Currently, any time an lwb completes, the vdev(s) written to as a result
of that lwb will be issued a flush command. The intenion is so the data
written to that vdev is on stable storage, prior to communicating to any
waiting threads that their data is safe on disk.
The problem with this scheme, is that sometimes an lwb will not have any
threads waiting for it to complete. This can occur when there's async
activity that gets "converted" to sync requests, as a result of calling
the zil_async_to_sync() function via zil_commit_impl(). When this
occurs, the current code may issue many lwbs that don't have waiters
associated with them, resulting in many flush commands, potentially to
the same vdev(s).
For example, given a pool with a single vdev, and a single fsync() call
that results in 10 lwbs being written out (e.g. due to other async
writes), that will result in 10 flush commands to that single vdev (a
flush issued after each lwb write completes). Ideally, we'd only issue a
single flush command to that vdev, after all 10 lwb writes completed.
Further, and most important as it pertains to this change, since the
flush commands are often very impactful to the performance of the pool's
underlying storage, unnecessarily issuing these flush commands can
poorly impact the performance of the lwb writes themselves. Thus, we
need to avoid issuing flush commands when possible, in order to acheive
the best possible performance out of the pool's underlying storage.
This change attempts to address this problem by changing the ZIL's logic
to only issue a vdev flush command when it detects an lwb that has a
thread waiting for it to complete. When an lwb does not have threads
waiting for it, the responsibility of issuing the flush command to the
vdevs involved with that lwb's write is passed on to the "next" lwb.
It's only once a write for an lwb with waiters completes, do we issue
the vdev flush command(s). As a result, now when we issue the flush(s),
we will issue them to the vdevs involved with that specific lwb's write,
but potentially also to vdevs involved with "previous" lwb writes (i.e.
if the previous lwbs did not have waiters associated with them).
Thus, in our prior example with 10 lwbs, it's only once the last lwb
completes (which will be the lwb containing the waiter for the thread
that called fsync) will we issue the vdev flush command; all of the
other lwbs will find they have no waiters, so they'll pass the
responsibility of the flush to the "next" lwb (until reaching the last
lwb that has the waiter).
Porting Notes:
* Reconciled conflicts with the fastwrite feature.
Authored by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Approved by: Joshua M. Clulow <josh@sysmgr.org>
Ported-by: Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://www.illumos.org/issues/9962
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/545190c6Closes#8188
Since Linux does not have the Directory Name Lookup Cache, we don't need
the code to manage it.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#8031
The bug time sequence:
1. thread #1, `zfs_write` assign a txg "n".
2. In a same process, thread #2, mmap page fault (which means the
`mm_sem` is hold) occurred, `zfs_dirty_inode` open a txg failed,
and wait previous txg "n" completed.
3. thread #1 call `uiomove` to write, however page fault is occurred
in `uiomove`, which means it need `mm_sem`, but `mm_sem` is hold by
thread #2, so it stuck and can't complete, then txg "n" will
not complete.
So thread #1 and thread #2 are deadlocked.
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Grady Wong <grady.w@xtaotech.com>
Closes#7939
The ZFS range locking code in zfs_rlock.c/h depends on ZPL-specific
data structures, specifically znode_t. However, it's also used by
the ZVOL code, which uses a "dummy" znode_t to pass to the range
locking code.
We should clean this up so that the range locking code is generic
and can be used equally by ZPL and ZVOL, and also can be used by
future consumers that may need to run in userland (libzpool) as
well as the kernel.
Porting notes:
* Added missing sys/avl.h include to sys/zfs_rlock.h.
* Removed 'dbuf is within the locked range' ASSERTs from dmu_sync().
This was needed because ztest does not yet use a locked_range_t.
* Removed "Approved by:" tag requirement from OpenZFS commit
check to prevent needless warnings when integrating changes
which has not been merged to illumos.
* Reverted free_list range lock changes which were originally
needed to defer the cv_destroy() which was called immediately
after cv_broadcast(). With d2733258 this should be safe but
if not we may need to reintroduce this logic.
* Reverts: The following two commits were reverted and squashed in
to this change in order to make it easier to apply OpenZFS 9689.
- d88895a0, which removed the dummy znode from zvol_state
- e3a07cd0, which updated ztest to use range locks
* Preserved optimized rangelock comparison function. Preserved the
rangelock free list. The cv_destroy() function will block waiting
for all processes in cv_wait() to be scheduled and drop their
reference. This is done to ensure it's safe to free the condition
variable. However, blocking while holding the rl->rl_lock mutex
can result in a deadlock on Linux. A free list is introduced to
defer the cv_destroy() and kmem_free() until after the mutex is
released.
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
OpenZFS-issue: https://illumos.org/issues/9689
OpenZFS-commit: https://github.com/openzfs/openzfs/pull/680
External-issue: DLPX-58662
Closes#7980
The following patch introduces a few statistics on reads and writes
grouped by dataset. These statistics are implemented as kstats
(backed by aggregate sums for performance) and can be retrieved by
using the dataset objset ID number. The motivation for this change is
to provide some preliminary analytics on dataset usage/performance.
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes#7705
Commit torvalds/linux@95582b0 changes the inode i_atime, i_mtime,
and i_ctime members form timespec's to timespec64's to make them
2038 safe. As part of this change the current_time() function was
also updated to return the timespec64 type.
Resolve this issue by introducing a new inode_timespec_t type which
is defined to match the timespec type used by the inode. It should
be used when working with inode timestamps to ensure matching types.
The timestruc_t type under Illumos was used in a similar fashion but
was specified to always be a timespec_t. Rather than incorrectly
define this type all timespec_t types have been replaced by the new
inode_timespec_t type.
Finally, the kernel and user space 'sys/time.h' headers were aligned
with each other. They define as appropriate for the context several
constants as macros and include static inline implementation of
gethrestime(), gethrestime_sec(), and gethrtime().
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7643
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 <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
TEST_ZIMPORT_SKIP="yes"
Closes#7556
As of RHEL 7.5 the mainline fops.iterate() method was added to
the file_operations structure and is correctly detected by the
configure script.
Normally this is what we want, but in order to maintain KABI
compatibility the RHEL change additionally does the following:
* Requires that callers intending to use this extended interface
set the FMODE_KABI_ITERATE flag on the file structure when
opening the directory.
* Adds the fops.iterate() method to the end of the structure,
without removing fops.readdir().
This change updates the configure check to ignore the RHEL 7.5+
variant of fops.iterate() when detected. Instead fallback to
the fops.readdir() interface which will be available.
Finally, add the 'zpl_' prefix to the directory context wrappers
to avoid colliding with the kernel provided symbols when both
the fops.iterate() and fops.readdir() are provided by the kernel.
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7460Closes#7463
Commit cc63068 caused ENOSPC error when copy a large amount of files
between two directories. The reason is that the patch limits zap leaf
expansion to 2 retries, and return ENOSPC when failed.
The intent for limiting retries is to prevent pointlessly growing table
to max size when adding a block full of entries with same name in
different case in mixed mode. However, it turns out we cannot use any
limit on the retry. When we copy files from one directory in readdir
order, we are copying in hash order, one leaf block at a time. Which
means that if the leaf block in source directory has expanded 6 times,
and you copy those entries in that block, by the time you need to expand
the leaf in destination directory, you need to expand it 6 times in one
go. So any limit on the retry will result in error where it shouldn't.
Note that while we do use different salt for different directories, it
seems that the salt/hash function doesn't provide enough randomization
to the hash distance to prevent this from happening.
Since cc63068 has already been reverted. This patch adds it back and
removes the retry limit.
Also, as it turn out, failing on zap_add() has a serious side effect for
mzap_upgrade(). When upgrading from micro zap to fat zap, it will
call zap_add() to transfer entries one at a time. If it hit any error
halfway through, the remaining entries will be lost, causing those files
to become orphan. This patch add a VERIFY to catch it.
Reviewed-by: Sanjeev Bagewadi <sanjeev.bagewadi@gmail.com>
Reviewed-by: Richard Yao <ryao@gentoo.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Albert Lee <trisk@forkgnu.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes#7401Closes#7421
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 <mahrens@delphix.com>
Reviewed-by: Alex Reece <alex@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
OpenZFS-issue: https://www.illumos.org/issues/7614
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1ebCloses#6900
This reverts commit cc63068e95.
Under certain circumstances this change can result in an ENOSPC
error when adding new files to a directory. See #7401 for full
details.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Issue #7401
Cloes #7416
Calling uiomove() in mappedread() under the page lock can result
in a deadlock if the user space page needs to be faulted in.
Resolve the issue by dropping the page lock before the uiomove().
The inode range lock protects against concurrent updates via
zfs_read() and zfs_write().
Reviewed-by: Albert Lee <trisk@forkgnu.org>
Reviewed-by: Chunwei Chen <david.chen@nutanix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#7335Closes#7339
1) The Coverity Scan reports some issues for the project
quota patch, including:
1.1) zfs_prop_get_userquota() directly uses the const quota
type value as the condition check by wrong.
1.2) dmu_objset_userquota_get_ids() may cause dnode::dn_newgid
to be overwritten by dnode::dn->dn_oldprojid.
2) This patch fixes related issues. It also enhances the logic
for zfs_project_item_alloc() to avoid buffer overflow.
3) Skip project quota ability check if does not change project
quota related things (id or flag). Otherwise, it will cause
chattr (for other non project quota flags) operation failed
if project quota disabled.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Fan Yong <fan.yong@intel.com>
Closes#7251Closes#7265
Project quota is a new ZFS system space/object usage accounting
and enforcement mechanism. Similar as user/group quota, project
quota is another dimension of system quota. It bases on the new
object attribute - project ID.
Project ID is a numerical value to indicate to which project an
object belongs. An object only can belong to one project though
you (the object owner or privileged user) can change the object
project ID via 'chattr -p' or 'zfs project [-s] -p' explicitly.
The object also can inherit the project ID from its parent when
created if the parent has the project inherit flag (that can be
set via 'chattr +P' or 'zfs project -s [-p]').
By accounting the spaces/objects belong to the same project, we
can know how many spaces/objects used by the project. And if we
set the upper limit then we can control the spaces/objects that
are consumed by such project. It is useful when multiple groups
and users cooperate for the same project, or a user/group needs
to participate in multiple projects.
Support the following commands and functionalities:
zfs set projectquota@project
zfs set projectobjquota@project
zfs get projectquota@project
zfs get projectobjquota@project
zfs get projectused@project
zfs get projectobjused@project
zfs projectspace
zfs allow projectquota
zfs allow projectobjquota
zfs allow projectused
zfs allow projectobjused
zfs unallow projectquota
zfs unallow projectobjquota
zfs unallow projectused
zfs unallow projectobjused
chattr +/-P
chattr -p project_id
lsattr -p
This patch also supports tree quota based on the project quota via
"zfs project" commands set as following:
zfs project [-d|-r] <file|directory ...>
zfs project -C [-k] [-r] <file|directory ...>
zfs project -c [-0] [-d|-r] [-p id] <file|directory ...>
zfs project [-p id] [-r] [-s] <file|directory ...>
For "df [-i] $DIR" command, if we set INHERIT (project ID) flag on
the $DIR, then the proejct [obj]quota and [obj]used values for the
$DIR's project ID will be shown as the total/free (avail) resource.
Keep the same behavior as EXT4/XFS does.
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by Ned Bass <bass6@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Fan Yong <fan.yong@intel.com>
TEST_ZIMPORT_POOLS="zol-0.6.1 zol-0.6.2 master"
Change-Id: Ib4f0544602e03fb61fd46a849d7ba51a6005693c
Closes#6290
With "casesensitivity=mixed", zap_add() could fail when the number of
files/directories with the same name (varying in case) exceed the
capacity of the leaf node of a Fatzap. This results in a ASSERT()
failure as zfs_link_create() does not expect zap_add() to fail. The fix
is to handle these failures and rollback the transactions.
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Chunwei Chen <david.chen@nutanix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sanjeev Bagewadi <sanjeev.bagewadi@gmail.com>
Closes#7011Closes#7054
PROBLEM
=======
When `dmu_tx_assign` is called from `zil_lwb_write_issue`, it's possible
for either `ERESTART` or `EIO` to be returned.
If `ERESTART` is returned, this will cause an assertion to fail directly
in `zil_lwb_write_issue`, where the code assumes the return value is
`EIO` if `dmu_tx_assign` returns a non-zero value. This can occur if the
SPA is suspended when `dmu_tx_assign` is called, and most often occurs
when running `zloop`.
If `EIO` is returned, this can cause assertions to fail elsewhere in the
ZIL code. For example, `zil_commit_waiter_timeout` contains the
following logic:
lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
In this case, if `dmu_tx_assign` returned `EIO` from within
`zil_lwb_write_issue`, the `lwb` variable passed in will not be issued
to disk. Thus, it's `lwb_state` field will remain `LWB_STATE_OPENED` and
this assertion will fail. `zil_commit_waiter_timeout` assumes that after
it calls `zil_lwb_write_issue`, the `lwb` will be issued to disk, and
doesn't handle the case where this is not true; i.e. it doesn't handle
the case where `dmu_tx_assign` returns `EIO`.
SOLUTION
========
This change modifies the `dmu_tx_assign` function such that `txg_how` is
a bitmask, rather than of the `txg_how_t` enum type. Now, the previous
`TXG_WAITED` semantics can be used via `TXG_NOTHROTTLE`, along with
specifying either `TXG_NOWAIT` or `TXG_WAIT` semantics.
Previously, when `TXG_WAITED` was specified, `TXG_NOWAIT` semantics was
automatically invoked. This was not ideal when using `TXG_WAITED` within
`zil_lwb_write_issued`, leading the problem described above. Rather, we
want to achieve the semantics of `TXG_WAIT`, while also preventing the
`tx` from being penalized via the dirty delay throttling.
With this change, `zil_lwb_write_issued` can acheive the semtantics that
it requires by passing in the value `TXG_WAIT | TXG_NOTHROTTLE` to
`dmu_tx_assign`.
Further, consumers of `dmu_tx_assign` wishing to achieve the old
`TXG_WAITED` semantics can pass in the value `TXG_NOWAIT | TXG_NOTHROTTLE`.
Authored by: Prakash Surya <prakash.surya@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Porting Notes:
- Additionally updated `zfs_tmpfile` to use `TXG_NOTHROTTLE`
OpenZFS-issue: https://www.illumos.org/issues/8997
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/19ea6cb0f9Closes#7084
Authored by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Prakash Surya <prakash.surya@delphix.com>
Problem
=======
The current implementation of zil_commit() can introduce significant
latency, beyond what is inherent due to the latency of the underlying
storage. The additional latency comes from two main problems:
1. When there's outstanding ZIL blocks being written (i.e. there's
already a "writer thread" in progress), then any new calls to
zil_commit() will block waiting for the currently oustanding ZIL
blocks to complete. The blocks written for each "writer thread" is
coined a "batch", and there can only ever be a single "batch" being
written at a time. When a batch is being written, any new ZIL
transactions will have to wait for the next batch to be written,
which won't occur until the current batch finishes.
As a result, the underlying storage may not be used as efficiently
as possible. While "new" threads enter zil_commit() and are blocked
waiting for the next batch, it's possible that the underlying
storage isn't fully utilized by the current batch of ZIL blocks. In
that case, it'd be better to allow these new threads to generate
(and issue) a new ZIL block, such that it could be serviced by the
underlying storage concurrently with the other ZIL blocks that are
being serviced.
2. Any call to zil_commit() must wait for all ZIL blocks in its "batch"
to complete, prior to zil_commit() returning. The size of any given
batch is proportional to the number of ZIL transaction in the queue
at the time that the batch starts processing the queue; which
doesn't occur until the previous batch completes. Thus, if there's a
lot of transactions in the queue, the batch could be composed of
many ZIL blocks, and each call to zil_commit() will have to wait for
all of these writes to complete (even if the thread calling
zil_commit() only cared about one of the transactions in the batch).
To further complicate the situation, these two issues result in the
following side effect:
3. If a given batch takes longer to complete than normal, this results
in larger batch sizes, which then take longer to complete and
further drive up the latency of zil_commit(). This can occur for a
number of reasons, including (but not limited to): transient changes
in the workload, and storage latency irregularites.
Solution
========
The solution attempted by this change has the following goals:
1. no on-disk changes; maintain current on-disk format.
2. modify the "batch size" to be equal to the "ZIL block size".
3. allow new batches to be generated and issued to disk, while there's
already batches being serviced by the disk.
4. allow zil_commit() to wait for as few ZIL blocks as possible.
5. use as few ZIL blocks as possible, for the same amount of ZIL
transactions, without introducing significant latency to any
individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks.
In theory, with these goals met, the new allgorithm will allow the
following improvements:
1. new ZIL blocks can be generated and issued, while there's already
oustanding ZIL blocks being serviced by the storage.
2. the latency of zil_commit() should be proportional to the underlying
storage latency, rather than the incoming synchronous workload.
Porting Notes
=============
Due to the changes made in commit 119a394ab0, the lifetime of an itx
structure differs than in OpenZFS. Specifically, the itx structure is
kept around until the data associated with the itx is considered to be
safe on disk; this is so that the itx's callback can be called after the
data is committed to stable storage. Since OpenZFS doesn't have this itx
callback mechanism, it's able to destroy the itx structure immediately
after the itx is committed to an lwb (before the lwb is written to
disk).
To support this difference, and to ensure the itx's callbacks can still
be called after the itx's data is on disk, a few changes had to be made:
* A list of itxs was added to the lwb structure. This list contains
all of the itxs that have been committed to the lwb, such that the
callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(),
after the data for the itxs is committed to disk.
* A list of itxs was added on the stack of the zil_process_commit_list()
function; the "nolwb_itxs" list. In some circumstances, an itx may
not be committed to an lwb (e.g. if allocating the "next" ZIL block
on disk fails), so this list is used to keep track of which itxs
fall into this state, such that their callbacks can be called after
the ZIL's writer pipeline is "stalled".
* The logic to actually call the itx's callback was moved into the
zil_itx_destroy() function. Since all consumers of zil_itx_destroy()
were effectively performing the same logic (i.e. if callback is
non-null, call the callback), it seemed like useful code cleanup to
consolidate this logic into a single function.
Additionally, the existing Linux tracepoint infrastructure dealing with
the ZIL's probes and structures had to be updated to reflect these code
changes. Specifically:
* The "zil__cw1" and "zil__cw2" probes were removed, so they had to be
removed from "trace_zil.h" as well.
* Some of the zilog structure's fields were removed, which affected
the tracepoint definitions of the structure.
* New tracepoints had to be added for the following 3 new probes:
* zil__process__commit__itx
* zil__process__normal__itx
* zil__commit__io__error
OpenZFS-issue: https://www.illumos.org/issues/8585
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3aCloses#6566
Resolve new warnings and errors from cppcheck v1.80.
* [lib/libshare/libshare.c:543]: (warning)
Possible null pointer dereference: protocol
* [lib/libzfs/libzfs_dataset.c:2323]: (warning)
Possible null pointer dereference: srctype
* [lib/libzfs/libzfs_import.c:318]: (error)
Uninitialized variable: link
* [module/zfs/abd.c:353]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:353]: (error) Uninitialized variable: i
* [module/zfs/abd.c:385]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:385]: (error) Uninitialized variable: i
* [module/zfs/abd.c:553]: (error) Uninitialized variable: i
* [module/zfs/abd.c:553]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:763]: (error) Uninitialized variable: i
* [module/zfs/abd.c:763]: (error) Uninitialized variable: sg
* [module/zfs/abd.c:305]: (error) Uninitialized variable: tmp_page
* [module/zfs/zpl_xattr.c:342]: (warning)
Possible null pointer dereference: value
* [module/zfs/zvol.c:208]: (error) Uninitialized variable: p
Convert the following suppression to inline.
* [module/zfs/zfs_vnops.c:840]: (error)
Possible null pointer dereference: aiov
Exclude HAVE_UIO_ZEROCOPY and HAVE_DNLC from analysis since
these macro's will never be defined until this functionality
is implemented.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#6879
On Linux, ftruncate(2) always changes the file timestamps, even if the
file size is not changed. However, in case of a successfull
truncate(2), the timestamps are updated only if the file size changes.
This translates to the VFS calling the ZFS Posix Layer "setattr"
function (zpl_setattr) with ATTR_MTIME and ATTR_CTIME unconditionally
set on the iattr mask only when doing a ftruncate(2), while the
truncate(2) is left to the filesystem implementation to be dealt with.
This behaviour is consistent with POSIX:2004/SUSv3 specifications
where there's no explicit requirement for file size changes to update
the timestamps only for ftruncate(2):
http://pubs.opengroup.org/onlinepubs/009695399/functions/truncate.htmlhttp://pubs.opengroup.org/onlinepubs/009695399/functions/ftruncate.html
This has been later updated in POSIX:2008/SUSv4 where, for both
truncate(2)/ftruncate(2), there's no mention of this size change
requirement:
http://austingroupbugs.net/view.php?id=489http://pubs.opengroup.org/onlinepubs/9699919799/functions/truncate.htmlhttp://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
Unfortunately the Linux VFS is still calling into the ZPL without
ATTR_MTIME/ATTR_CTIME set in the truncate(2) case: we fix this by
explicitly updating the timestamps when detecting the ATTR_SIZE bit,
which is always set in do_truncate(), on the iattr mask.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6811Closes#6819
Several issues were uncovered by running stress tests with zfs
encryption and raw sends in particular. The issues and their
associated fixes are as follows:
* arc_read_done() has the ability to chain several requests for
the same block of data via the arc_callback_t struct. In these
cases, the ARC would only use the first request's dsobj from
the bookmark to decrypt the data. This is problematic because
the first request might be a prefetch zio which is able to
handle the key not being loaded, while the second might use a
different key that it is sure will work. The fix here is to
pass the dsobj with each individual arc_callback_t so that each
request can attempt to decrypt the data separately.
* DRR_FREE and DRR_FREEOBJECT records in a send file were not
having their transactions properly tagged as raw during raw
sends, which caused a panic when the dbuf code attempted to
decrypt these blocks.
* traverse_prefetch_metadata() did not properly set
ZIO_FLAG_SPECULATIVE when issuing prefetch IOs.
* Added a few asserts and code cleanups to ensure these issues
are more detectable in the future.
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Currently `if` statement includes an assignment (from a function return
value) and a equality check. The parenthesis are in the incorrect place,
currently the code clobbers the function return value because of this.
We can fix this by simplifying the `if` statement.
`if (foo != 0)`
can be more succinctly expressed as
`if (foo)`
Remove the equality check, add parenthesis to correct the statement.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Closes#6685Close#6719
ZFS buildbot STYLE builder was moved to Ubuntu 17.04
which has a newer version of cppcheck. Handle the
new cppcheck errors.
uu_* functions removed in this commit were unused
and effectively dead code. They are now retired.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#6653
Since OpenZFS 7578 (1b7c1e5) if we have a ZVOL with logbias=throughput
we will force WR_INDIRECT itxs in zvol_log_write() setting itx->itx_lr
offset and length to the offset and length of the BIO from
zvol_write()->zvol_log_write(): these offset and length are later used
to take a range lock in zillog->zl_get_data function: zvol_get_data().
Now suppose we have a ZVOL with blocksize=8K and push 4K writes to
offset 0: we will only be range-locking 0-4096. This means the
ASSERTion we make in dbuf_unoverride() is no longer valid because now
dmu_sync() is called from zilog's get_data functions holding a partial
lock on the dbuf.
Fix this by taking a range lock on the whole block in zvol_get_data().
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#6238Closes#6315Closes#6356Closes#6477
When doing read on a file open with O_SYNC, it will trigger zil_commit.
However for snapshot, there's no zil, so we shouldn't be doing that.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#6478Closes#6494
Update many return and assignment statements to follow the convention
of using the SET_ERROR macro when returning a hard-coded non-zero
value from a function. This aids debugging by recording the error
codes in the debug log.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#6441
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Giuseppe Di Natale <dinatale2@llnl.gov>
The problem is that zfs_get_data() supplies a stale zgd_bp to
dmu_sync(), which we then nopwrite against.
zfs_get_data() doesn't hold any DMU-related locks, so after it
copies db_blkptr to zgd_bp, dbuf_write_ready() could change
db_blkptr, and dbuf_write_done() could remove the dirty record.
dmu_sync() then sees the stale BP and that the dbuf it not dirty,
so it is eligible for nop-writing.
The fix is for dmu_sync() to copy db_blkptr to zgd_bp after
acquiring the db_mtx. We could still see a stale db_blkptr,
but if it is stale then the dirty record will still exist and
thus we won't attempt to nopwrite.
OpenZFS-issue: https://www.illumos.org/issues/8378
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3127742Closes#6293
Fixup commit 66aca24. We should have equivalent return
values as generic_file_llseek() and advance to end of file.
Reviewed-by: Richard Yao <ryao@gentoo.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Tested-by: bunder2015 <omfgbunder@gmail.com>
Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Closes#6050Closes#6053
Force flushing of txg's can be painfully slow when competing for disk
IO, since this is a process meant to execute asynchronously. Optimize
this path via allowing data/hole seeking if the file is clean, but if
dirty fall back to old logic. This is a compromise to disabling the
feature entirely.
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Closes#4306Closes#5962
Several functions were renamed when ZFS was originally ported to
Linux. Revert the code to the original names to minimize the
delta with upstream OpenZFS.
zfs_sb_teardown -> zfsvfs_teardown
zfs_sb_create -> zfsvfs_create
zfs_sb_setup -> zfsvfs_setup
zfs_sb_free -> zfsvfs_free
get_zfs_sb -> getzfsvfs
zfs_sb_hold -> zfsvfs_hold
zfs_sb_rele -> zfsvfs_rele
zfs_sb_prune_aliases -> zfs_prune_aliases (Linux-only)
zfs_sb_prune -> zfs_prune (Linux only)
Align the zfs_vnops.h and zfs_vfsops.h with upstream as much
as possible. Several prototypes were removed and those that
remain were reordered.
Move the EXPORT_SYMBOL lines to the end of the source files
for consistency with the other source files.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The use of zfs_sb_t instead of zfsvfs_t results in unnecessary
conflicts with the upstream source. Change all instances of
zfs_sb_t to zfsvfs_t including updating the variables names.
Whenever possible the code was updated to be consistent with
hope it appears in the upstream OpenZFS source.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Newer versions of cppcheck find the potential NULL pointer
bug in zfs_write(). The function is difficult to refactor without
extensive work, so suppress the potential NULL pointer error
which cannot occur for now.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#5882
The current implementation for allowing nfs to access snapdir is very buggy.
It uses a special fh for snapdirs, such that the next time nfsd does
fh_to_dentry, it actually returns the root inode inside the snapshot. So nfsd
never knows it cross a mountpoint.
The problem is that nfsd will not hold a reference on the vfsmount of the
snapshot. This cause auto unmounter to unmount the snapshot even though nfs is
still holding dentries in it.
To fix this, we return the inode for the snapdirs themselves. However, we also
trigger automount upon fh_to_dentry, and return ESTALE so nfsd will revalidate
and see the mountpoint and do crossmnt.
Because nfsd will now be aware that these are different filesystems users
must add crossmnt to their export options to access snapshot directories.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes#3794Closes#4716Closes#5810Closes#5833
As explicitly stated in section 2 of the 'Programming rules'
comments at the top of zfs_vnops.c.
If you must call iput() within a tx then use zfs_iput_async().
Move iput() calls after dmu_tx_commit() / dmu_tx_abort when
possible. When not possible convert the iput() calls to
zfs_iput_async().
Reviewed-by: Don Brady <don.brady@intel.com>
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#5758
