Commit Graph

142 Commits

Author SHA1 Message Date
Paul Dagnelie
a370182fed Add SCSI_PASSTHROUGH to zvols to enable UNMAP support
When exporting ZVOLs as SCSI LUNs, by default Windows will not
issue them UNMAP commands. This reduces storage efficiency in
many cases.

We add the SCSI_PASSTHROUGH flag to the zvol's device queue,
which lets the SCSI target logic know that it can handle SCSI
commands.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: John Gallagher <john.gallagher@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #8933
2019-06-21 09:40:56 -07:00
Matthew Ahrens
b8738257c2 make zil max block size tunable
We've observed that on some highly fragmented pools, most metaslab
allocations are small (~2-8KB), but there are some large, 128K
allocations.  The large allocations are for ZIL blocks.  If there is a
lot of fragmentation, the large allocations can be hard to satisfy.

The most common impact of this is that we need to check (and thus load)
lots of metaslabs from the ZIL allocation code path, causing sync writes
to wait for metaslabs to load, which can take a second or more.  In the
worst case, we may not be able to satisfy the allocation, in which case
the ZIL will resort to txg_wait_synced() to ensure the change is on
disk.

To provide a workaround for this, this change adds a tunable that can
reduce the size of ZIL blocks.

External-issue: DLPX-61719
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #8865
2019-06-10 11:48:42 -07:00
Brian Behlendorf
515ddf6504
Fix errant EFAULT during writes (#8719)
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 #8640 
Closes #8719
2019-05-08 10:04:04 -07:00
John Gallagher
1eacf2b3b0 Improve rate at which new zvols are processed
The kernel function which adds new zvols as disks to the system,
add_disk(), briefly opens and closes the zvol as part of its work.
Closing a zvol involves waiting for two txgs to sync. This, combined
with the fact that the taskq processing new zvols is single threaded,
makes this processing new zvols slow.

Waiting for these txgs to sync is only necessary if the zvol has been
written to, which is not the case during add_disk(). This change adds
tracking of whether a zvol has been written to so that we can skip the
txg_wait_synced() calls when they are unnecessary.

This change also fixes the flags passed to blkdev_get_by_path() by
vdev_disk_open() to be FMODE_READ | FMODE_WRITE | FMODE_EXCL instead of
just FMODE_EXCL. The flags were being incorrectly calculated because
we were using the wrong version of vdev_bdev_mode().

Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
Closes #8526 
Closes #8615
2019-05-04 16:39:10 -07:00
loli10K
c44a3ec059 zvol: allow rename of in use ZVOL dataset
While ZFS allow renaming of in use ZVOLs at the DSL level without issues
the ZVOL layer does not correctly update the renamed dataset if the
device node is open (zv->zv_open_count > 0): trying to access the stale
dataset name, for instance during a zfs receive, will cause the
following failure:

VERIFY3(zv->zv_objset->os_dsl_dataset->ds_owner == zv) failed ((null) == ffff8800dbb6fc00)
PANIC at zvol.c:1255:zvol_resume()
Showing stack for process 1390
CPU: 0 PID: 1390 Comm: zfs Tainted: P           O  3.16.0-4-amd64 #1 Debian 3.16.51-3
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 0000000000000000 ffffffff8151ea00 ffffffffa0758a80 ffff88028aefba30
 ffffffffa0417219 ffff880037179220 ffffffff00000030 ffff88028aefba40
 ffff88028aefb9e0 2833594649524556 6f5f767a3e2d767a 6f3e2d7465736a62
Call Trace:
 [<0>] ? dump_stack+0x5d/0x78
 [<0>] ? spl_panic+0xc9/0x110 [spl]
 [<0>] ? mutex_lock+0xe/0x2a
 [<0>] ? zfs_refcount_remove_many+0x1ad/0x250 [zfs]
 [<0>] ? rrw_exit+0xc8/0x2e0 [zfs]
 [<0>] ? mutex_lock+0xe/0x2a
 [<0>] ? dmu_objset_from_ds+0x9a/0x250 [zfs]
 [<0>] ? dmu_objset_hold_flags+0x71/0xc0 [zfs]
 [<0>] ? zvol_resume+0x178/0x280 [zfs]
 [<0>] ? zfs_ioc_recv_impl+0x88b/0xf80 [zfs]
 [<0>] ? zfs_refcount_remove_many+0x1ad/0x250 [zfs]
 [<0>] ? zfs_ioc_recv+0x1c2/0x2a0 [zfs]
 [<0>] ? dmu_buf_get_user+0x13/0x20 [zfs]
 [<0>] ? __alloc_pages_nodemask+0x166/0xb50
 [<0>] ? zfsdev_ioctl+0x896/0x9c0 [zfs]
 [<0>] ? handle_mm_fault+0x464/0x1140
 [<0>] ? do_vfs_ioctl+0x2cf/0x4b0
 [<0>] ? __do_page_fault+0x177/0x410
 [<0>] ? SyS_ioctl+0x81/0xa0
 [<0>] ? async_page_fault+0x28/0x30
 [<0>] ? system_call_fast_compare_end+0x10/0x15

Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6263 
Closes #8371
2019-02-22 15:38:42 -08:00
Tomohiro Kusumi
9abbee4912 Don't enter zvol's rangelock for read bio with size 0
The SCST driver (SCSI target driver implementation) and possibly
others may issue read bio's with a length of zero bytes. Although
this is unusual, such bio's issued under certain condition can cause
kernel oops, due to how rangelock is implemented.

rangelock_add_reader() is not made to handle overlap of two (or more)
ranges from read bio's with the same offset when one of them has size
of 0, even though they conceptually overlap. Allowing them to enter
rangelock results in kernel oops by dereferencing invalid pointer,
or assertion failure on AVL tree manipulation with debug enabled
kernel module.

For example, this happens when read bio whose (offset, size) is
(0, 0) enters rangelock followed by another read bio with (0, 4096)
when (0, 0) rangelock is still locked, when there are no pending
write bio's. It can also happen with reverse order, which is (0, N)
followed by (0, 0) when (0, N) is still locked. More details
mentioned in #8379.

Kernel Oops on ->make_request_fn() of ZFS volume
https://github.com/zfsonlinux/zfs/issues/8379

Prevent this by returning bio with size 0 as success without entering
rangelock. This has been done for write bio after checking flusher
bio case (though not for the same reason), but not for read bio.

Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes #8379 
Closes #8401
2019-02-20 10:14:36 -08:00
Tomohiro Kusumi
2d76ab9e42 Fix obsolete comment on rangelock
5d43cc9a59 renamed it to rangelock_enter().

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes #8408
2019-02-14 15:13:58 -08:00
Tom Caputi
b5d693581d Fix bad kmem_free() in zvol_rename_minors_impl()
Currently, zvol_rename_minors_impl() calls kmem_asprintf()
to allocate and initialize a string. This function is a thin
wrapper around the kernel's kvasprintf() and does not call
into the SPL's kmem tracking code when it is enabled. However,
this function frees the string with the tracked kmem_free()
instead of the untracked strfree(), which causes the SPL
kmem tracking code to believe that the function is attempting
to free memory it never allocated, triggering an ASSERT. This
patch simply corrects this issue.

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #8307
2019-01-23 11:38:05 -08:00
Prakash Surya
900d09b285 OpenZFS 9962 - zil_commit should omit cache thrash
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/545190c6
Closes #8188
2018-12-07 11:09:42 -08:00
Matt Ahrens
5d43cc9a59 OpenZFS 9689 - zfs range lock code should not be zpl-specific
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
2018-10-11 10:19:33 -07:00
Tom Caputi
47ab01a18f Always wait for txg sync when umounting dataset
Currently, when unmounting a filesystem, ZFS will only wait for
a txg sync if the dataset is dirty and not readonly. However, this
can be problematic in cases where a dataset is remounted readonly
immediately before being unmounted, which often happens when the
system is being shut down. Since encrypted datasets require that
all I/O is completed before the dataset is disowned, this issue
causes problems when write I/Os leak into the txgs after the
dataset is disowned, which can happen when sync=disabled.

While looking into fixes for this issue, it was discovered that
dsl_dataset_is_dirty() does not return B_TRUE when the dataset has
been removed from the txg dirty datasets list, but has not actually
been processed yet. Furthermore, the implementation is comletely
different from dmu_objset_is_dirty(), adding to the confusion.
Rather than relying on this function, this patch forces the umount
code path (and the remount readonly code path) to always perform a
txg sync on read-write datasets and removes the function altogether.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #7753
Closes #7795
2018-08-27 10:16:28 -07:00
Serapheim Dimitropoulos
a448a2557e Introduce read/write kstats per dataset
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
2018-08-20 09:52:37 -07:00
Brian Behlendorf
7b98f0d91f
Linux compat 4.18: check_disk_size_change()
Added support for the bops->check_events() interface which was
added in the 2.6.38 kernel to replace bops->media_changed().
Fully implementing this functionality allows the volume resize
code to rely on revalidate_disk(), which is the preferred
mechanism, and removes the need to use check_disk_size_change().

In order for bops->check_events() to lookup the zvol_state_t
stored in the disk->private_data the zvol_state_lock needs to
be held.  Since the check events interface may poll the mutex
has been converted to a rwlock for better concurrently.  The
rwlock need only be taken as a writer in the zvol_free() path
when disk->private_data is set to NULL.

The configure checks for the block_device_operations structure
were consolidated in a single kernel-block-device-operations.m4
file.

The ZFS_AC_KERNEL_BDEV_BLOCK_DEVICE_OPERATIONS configure checks
and assoicated dead code was removed.  This interface was added
to the 2.6.28 kernel which predates the oldest supported 2.6.32
kernel and will therefore always be available.

Updated maximum Linux version in META file.  The 4.17 kernel
was released on 2018-06-03 and ZoL is compatible with the
finalized kernel.

Reviewed-by: Boris Protopopov <boris.protopopov@actifio.com>
Reviewed-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7611
2018-06-15 15:05:21 -07:00
Giuseppe Di Natale
10f88c5cd5 Linux compat 4.16: blk_queue_flag_{set,clear}
queue_flag_{set,clear}_unlocked are now private interfaces in
the Linux kernel (https://github.com/torvalds/linux/commit/8a0ac14).
Use blk_queue_flag_{set,clear} interfaces which were introduced as
of https://github.com/torvalds/linux/commit/8814ce8.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes #7410
2018-04-10 10:32:14 -07:00
Giuseppe Di Natale
dd3e1e3083 Linux 4.16 compat: get_disk_and_module()
As of https://github.com/torvalds/linux/commit/fb6d47a, get_disk()
is now get_disk_and_module(). Add a configure check to determine
if we need to use get_disk_and_module().

Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes #7264
2018-03-05 12:44:35 -08:00
Tom Caputi
163a8c28dd ZIL claiming should not start user accounting
Currently, ZIL claiming dirties objsets which causes
dsl_pool_sync() to attempt to perform user accounting on
them. This causes problems for encrypted datasets that were
raw received before the system went offline since they
cannot perform user accounting until they have their keys
loaded. This triggers an ASSERT in zio_encrypt(). Since
encryption was added, the code now depends on the fact that
data should only be written when objsets are owned. This
patch adds a check in dmu_objset_do_userquota_updates()
to ensure that useraccounting is only done when the objsets
are actually owned for write. As part of this work, the
zfsvfs and zvol code was updated so that it no longer lies
about owning objsets readonly.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #6916 
Closes #7163
2018-02-20 16:27:31 -08:00
Tom Caputi
ae76f45cda Encryption Stability and On-Disk Format Fixes
The on-disk format for encrypted datasets protects not only
the encrypted and authenticated blocks themselves, but also
the order and interpretation of these blocks. In order to
make this work while maintaining the ability to do raw
sends, the indirect bps maintain a secure checksum of all
the MACs in the block below it along with a few other
fields that determine how the data is interpreted.

Unfortunately, the current on-disk format erroneously
includes some fields which are not portable and thus cannot
support raw sends. It is not possible to easily work around
this issue due to a separate and much smaller bug which
causes indirect blocks for encrypted dnodes to not be
compressed, which conflicts with the previous bug. In
addition, the current code generates incompatible on-disk
formats on big endian and little endian systems due to an
issue with how block pointers are authenticated. Finally,
raw send streams do not currently include dn_maxblkid when
sending both the metadnode and normal dnodes which are
needed in order to ensure that we are correctly maintaining
the portable objset MAC.

This patch zero's out the offending fields when computing
the bp MAC and ensures that these MACs are always
calculated in little endian order (regardless of the host
system's byte order). This patch also registers an errata
for the old on-disk format, which we detect by adding a
"version" field to newly created DSL Crypto Keys. We allow
datasets without a version (version 0) to only be mounted
for read so that they can easily be migrated. We also now
include dn_maxblkid in raw send streams to ensure the MAC
can be maintained correctly.

This patch also contains minor bug fixes and cleanups.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #6845
Closes #6864
Closes #7052
2018-02-02 11:37:16 -08:00
Prakash Surya
1ce23dcaff OpenZFS 8585 - improve batching done in zil_commit()
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/5d95a3a
Closes #6566
2017-12-05 09:39:16 -08:00
Brian Behlendorf
94183a9d8a
Update for cppcheck v1.80
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
2017-11-18 14:08:00 -08:00
Brian Behlendorf
867959b588
OpenZFS 8081 - Compiler warnings in zdb
Fix compiler warnings in zdb.  With these changes, FreeBSD can compile
zdb with all compiler warnings enabled save -Wunused-parameter.

usr/src/cmd/zdb/zdb.c
usr/src/cmd/zdb/zdb_il.c
usr/src/uts/common/fs/zfs/sys/sa.h
usr/src/uts/common/fs/zfs/sys/spa.h
	Fix numerous warnings, including:
	* const-correctness
	* shadowing global definitions
	* signed vs unsigned comparisons
	* missing prototypes, or missing static declarations
	* unused variables and functions
	* Unreadable array initializations
	* Missing struct initializers

usr/src/cmd/zdb/zdb.h
	Add a header file to declare common symbols

usr/src/lib/libzpool/common/sys/zfs_context.h
usr/src/uts/common/fs/zfs/arc.c
usr/src/uts/common/fs/zfs/dbuf.c
usr/src/uts/common/fs/zfs/spa.c
usr/src/uts/common/fs/zfs/txg.c
	Add a function prototype for zk_thread_create, and ensure that every
	callback supplied to this function actually matches the prototype.

usr/src/cmd/ztest/ztest.c
usr/src/uts/common/fs/zfs/sys/zil.h
usr/src/uts/common/fs/zfs/zfs_replay.c
usr/src/uts/common/fs/zfs/zvol.c
	Add a function prototype for zil_replay_func_t, and ensure that
	every function of this type actually matches the prototype.

usr/src/uts/common/fs/zfs/sys/refcount.h
	Change FTAG so it discards any constness of __func__, necessary
	since existing APIs expect it passed as void *.

Porting Notes:
- Many of these fixes have already been applied to Linux.  For
  consistency the OpenZFS version of a change was applied if the
  warning was addressed in an equivalent but different fashion.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Authored by: Alan Somers <asomers@gmail.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/8081
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/843abe1b8a
Closes #6787
2017-10-27 12:46:35 -07:00
Giuseppe Di Natale
787acae0b5 Linux 3.14 compat: IO acct, global_page_state, etc
generic_start_io_acct/generic_end_io_acct in the master
branch of the linux kernel requires that the request_queue
be provided.

Move the logic from freemem in the spl to arc_free_memory
in arc.c. Do this so we can take advantage of global_page_state
interface checks in zfs.

Upstream kernel replaced struct block_device with
struct gendisk in struct bio. Determine if the
function bio_set_dev exists during configure
and have zfs use that if it exists.

bio_set_dev https://github.com/torvalds/linux/commit/74d4699
global_node_page_state https://github.com/torvalds/linux/commit/75ef718
io acct https://github.com/torvalds/linux/commit/d62e26b

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes #6635
2017-09-16 11:00:19 -07:00
Brian Behlendorf
5c214ae318 Fix volume WR_INDIRECT log replay
The portion of the zvol_replay_write() handler responsible for
replaying indirect log records for some reason never existed.
As a result indirect log records were not being correctly replayed.

This went largely unnoticed since the majority of zvol log records
were of the type WR_COPIED or WR_NEED_COPY prior to OpenZFS 7578.

This patch updates zvol_replay_write() to correctly handle these
log records and adds a new test case which verifies volume replay
to prevent any regression.  The existing test case which verified
replay on filesystem was renamed slog_replay_fs.ksh for clarity.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6603 
Closes #6615
2017-09-08 15:07:00 -07:00
LOLi
f763c3d1df Fix range locking in ZIL commit codepath
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 #6238 
Closes #6315 
Closes #6356 
Closes #6477
2017-08-21 08:59:48 -07:00
Tom Caputi
b525630342 Native Encryption for ZFS on Linux
This change incorporates three major pieces:

The first change is a keystore that manages wrapping
and encryption keys for encrypted datasets. These
commands mostly involve manipulating the new
DSL Crypto Key ZAP Objects that live in the MOS. Each
encrypted dataset has its own DSL Crypto Key that is
protected with a user's key. This level of indirection
allows users to change their keys without re-encrypting
their entire datasets. The change implements the new
subcommands "zfs load-key", "zfs unload-key" and
"zfs change-key" which allow the user to manage their
encryption keys and settings. In addition, several new
flags and properties have been added to allow dataset
creation and to make mounting and unmounting more
convenient.

The second piece of this patch provides the ability to
encrypt, decyrpt, and authenticate protected datasets.
Each object set maintains a Merkel tree of Message
Authentication Codes that protect the lower layers,
similarly to how checksums are maintained. This part
impacts the zio layer, which handles the actual
encryption and generation of MACs, as well as the ARC
and DMU, which need to be able to handle encrypted
buffers and protected data.

The last addition is the ability to do raw, encrypted
sends and receives. The idea here is to send raw
encrypted and compressed data and receive it exactly
as is on a backup system. This means that the dataset
on the receiving system is protected using the same
user key that is in use on the sending side. By doing
so, datasets can be efficiently backed up to an
untrusted system without fear of data being
compromised.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #494 
Closes #5769
2017-08-14 10:36:48 -07:00
Boris Protopopov
5146d802b4 zv_suspend_lock in zvol_open()/zvol_release()
Acquire zv_suspend_lock on first open and last close only.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Closes #6342
2017-08-09 11:10:47 -07:00
LOLi
c7a7601c08 Fix volmode=none property behavior at import time
At import time spa_import() calls zvol_create_minors() directly: with
the current implementation we have no way to avoid device node
creation when volmode=none.

Fix this by enforcing volmode=none directly in zvol_alloc().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6426
2017-07-31 11:07:05 -07:00
LOLi
cf8738d853 Add port of FreeBSD 'volmode' property
The volmode property may be set to control the visibility of ZVOL
block devices.

This allow switching ZVOL between three modes:
   full - existing fully functional behaviour (default)
   dev  - hide partitions on ZVOL block devices
   none - not exposing volumes outside ZFS

Additionally the new zvol_volmode module parameter can be used to
control the default behaviour.

This functionality can be used, for instance, on "backup" pools to
avoid cluttering /dev with unneeded zd* devices.

Original-patch-by: mav <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>

FreeBSD-commit: https://github.com/freebsd/freebsd/commit/dd28e6bb
Closes #1796 
Closes #3438 
Closes #6233
2017-07-12 13:05:37 -07:00
Arkadiusz Bubała
94b25662c5 Reschedule processes on -ERESTARTSYS
On the single core machine the system may hang when the
spa_namespare_lock acquisition fails in the zvol_first_open
function. It returns -ERESTARTSYS error what causes the
endless loop in __blkdev_get function.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Arkadiusz Bubała <arkadiusz.bubala@open-e.com>
Closes #6283 
Closes #6312
2017-07-06 08:38:24 -07:00
Matthew Ahrens
02dc43bc46 OpenZFS 8378 - crash due to bp in-memory modification of nopwrite block
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/3127742
Closes #6293
2017-07-04 15:41:24 -07:00
Tony Hutter
682ce104cd GCC 7.1 fixes
GCC 7.1 with will warn when we're not checking the snprintf()
return code in cases where the buffer could be truncated. This
patch either checks the snprintf return code (where applicable),
or simply disables the warnings (ztest.c).

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #6253
2017-06-28 10:05:16 -07:00
Boris Protopopov
58404a73db Refine use of zv_state_lock.
Use zv_state_lock to protect all members of zvol_state structure, add
relevant ASSERT()s. Take zv_suspend_lock before zv_state_lock, do not
hold zv_state_lock across suspend/resume.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Closes #6226
2017-06-27 12:51:44 -04:00
Boris Protopopov
ef4be34a64 Avoid 'queue not locked' warning at pool import.
Use queue_flag_set_unlocked() in zvol_alloc().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Issue #6226
2017-06-15 11:16:19 -07:00
LOLi
97f8d7961e Fix zvol_state_t->zv_open_count race
5559ba0 added zv_state_lock to protect zvol_state_t internal data:
this, however, doesn't guard zv->zv_open_count and
zv->zv_disk->private_data in zvol_remove_minors_impl().

Fix this by taking zv->zv_state_lock before we check its zv_open_count.

P1 (z_zvol)                       P2 (systemd-udevd)
---                               ---
zvol_remove_minors_impl()
: zv->zv_open_count==0
                                  zvol_open()
                                  ->mutex_enter(zv_state_lock)
                                  : zv->zv_open_count++
                                  ->mutex_exit(zv_state_lock)
->mutex_enter(zv->zv_state_lock)
->zvol_remove(zv)
->mutex_exit(zv->zv_state_lock)
: zv->zv_disk->private_data = NULL
->zvol_free()
-->ASSERT(zv->zv_open_count==0) *
                                  zvol_release()
                                  : zv = disk->private_data
                                  ->ASSERT(zv && zv->zv_open_count>0) *
---                               ---
* ASSERT() fails

Reviewed by: Boris Protopopov <bprotopopov@hotmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6213
2017-06-15 11:08:45 -07:00
Richard Yao
8f7933fec9 Fix zvol_init error handling
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@prophetstor.com>
2017-06-13 15:29:21 -04:00
Richard Yao
5228cf0116 Make zvol operations use _by_dnode routines
This continues what was started in
0eef1bde31 by fully converting zvols
to avoid unnecessary dnode_hold() calls. This saves a small amount
of CPU time and slightly improves latencies of operations on zvols.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@prophetstor.com>
Closes #6058
2017-06-13 09:18:08 -07:00
Giuseppe Di Natale
1b7c1e5ce9 OpenZFS 7578 - Fix/improve some aspects of ZIL writing
- After some ZIL changes 6 years ago zil_slog_limit got partially broken
due to zl_itx_list_sz not updated when async itx'es upgraded to sync.
Actually because of other changes about that time zl_itx_list_sz is not
really required to implement the functionality, so this patch removes
some unneeded broken code and variables.

 - Original idea of zil_slog_limit was to reduce chance of SLOG abuse by
single heavy logger, that increased latency for other (more latency critical)
loggers, by pushing heavy log out into the main pool instead of SLOG.  Beside
huge latency increase for heavy writers, this implementation caused double
write of all data, since the log records were explicitly prepared for SLOG.
Since we now have I/O scheduler, I've found it can be much more efficient
to reduce priority of heavy logger SLOG writes from ZIO_PRIORITY_SYNC_WRITE
to ZIO_PRIORITY_ASYNC_WRITE, while still leave them on SLOG.

 - Existing ZIL implementation had problem with space efficiency when it
has to write large chunks of data into log blocks of limited size.  In some
cases efficiency stopped to almost as low as 50%.  In case of ZIL stored on
spinning rust, that also reduced log write speed in half, since head had to
uselessly fly over allocated but not written areas.  This change improves
the situation by offloading problematic operations from z*_log_write() to
zil_lwb_commit(), which knows real situation of log blocks allocation and
can split large requests into pieces much more efficiently.  Also as side
effect it removes one of two data copy operations done by ZIL code WR_COPIED
case.

 - While there, untangle and unify code of z*_log_write() functions.
Also zfs_log_write() alike to zvol_log_write() can now handle writes crossing
block boundary, that may also improve efficiency if ZPL is made to do that.

Sponsored by:   iXsystems, Inc.

Authored by: Alexander Motin <mav@FreeBSD.org>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Steven Hartland <steven.hartland@multiplay.co.uk>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Yao <ryao@gentoo.org>
Ported-by: Giuseppe Di Natale <dinatale2@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/7578
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/aeb13ac
Closes #6191
2017-06-09 09:15:37 -07:00
LOLi
92aceb2a7e Fix "snapdev" property issues
When inheriting the "snapdev" property to we don't always call
zfs_prop_set_special(): this prevents device nodes from being created in
certain situations. Because "snapdev" is the only *special* property
that is also inheritable we need to call zfs_prop_set_special() even
when we're not reverting it to the received value ('zfs inherit -S').

Additionally, fix a NULL pointer dereference accidentally introduced in
5559ba0 that can be triggered when setting the "snapdev" property to
the value "hidden" twice.

Finally, add a new test case "zvol_misc_snapdev" to the ZFS Test Suite.

Reviewed by: Boris Protopopov <bprotopopov@hotmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6131 
Closes #6175 
Closes #6176
2017-06-02 07:17:00 -07:00
LOLi
3f7d0418dc Fix memory leak in zvol_set_volsize()
Move kmem_free() so it's called for every error path: this is
preferred over making `dmu_object_info_t doi` local to accommodate
older kernels with limited stacks.

Reviewed by: Boris Protopopov <bprotopopov@hotmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6177
2017-05-31 12:52:12 -07:00
Boris Protopopov
2d82116e80 Fix ida leak in zvol_create_minor_impl
Added missing ida_simple_remove() in the error handling path.

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Closes #6159 
Closes #6172
2017-05-26 17:50:25 -07:00
Brian Behlendorf
261c013fbf Revert "Fix "snapdev" property inheritance behaviour"
This reverts commit 959f56b993.
An issue was uncovered by the new zvol_misc_snapdev test case
which needs to be investigated and resolved.

Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6174 
Issue #6131
2017-05-26 11:40:44 -07:00
LOLi
959f56b993 Fix "snapdev" property inheritance behaviour
When inheriting the "snapdev" property to we don't always call
zfs_prop_set_special(): this prevents device nodes from being created in
certain situations. Because "snapdev" is the only *special* property
that is also inheritable we need to call zfs_prop_set_special() even
when we're not reverting it to the received value ('zfs inherit -S').

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #6131
2017-05-25 16:43:46 -07:00
Boris Protopopov
5559ba094f Introduce zv_state_lock
The lock is designed to protect internal state of zvol_state_t and
to avoid taking spa_namespace_lock (e.g. in dmu_objset_own() code path)
while holding zvol_stat_lock. Refactor the code accordingly.

Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3484
Closes #6065
Closes #6134
2017-05-16 19:44:06 -04:00
Boris Protopopov
07783588bc Revert commit 1ee159f4
Fix lock order inversion with zvol_open() as it did not account
for use of zvols as vdevs. The latter use cases resulted in the
lock order inversion deadlocks that involved spa_namespace_lock
and bdev->bd_mutex.

Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #6065
Issue #6134
2017-05-16 19:42:47 -04:00
Brian Behlendorf
8fa5250f5d Default to zvol_request_async=0
Change the default ZVOL behavior so requests are handled asynchronously.
This behavior is functionally the same as in the zfs-0.6.4 release.

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #5902
2017-05-04 18:01:50 -04:00
Richard Yao
bc17f1047a Enable Linux read-ahead for a single page on ZVOLs
Linux has read-ahead logic designed to accelerate sequential workloads.
ZFS has its own read-ahead logic called zprefetch that operates on both
ZVOLs and datasets. Having two prefetchers active at the same time can
cause overprefetching, which unnecessarily reduces IOPS performance on
CoW filesystems like ZFS.

Testing shows that entirely disabling the Linux prefetch results in
a significant performance penalty for reads while commensurate benefits
are seen in random writes. It appears that read-ahead benefits are
inversely proportional to random write benefits, and so a single page
of Linux-layer read-ahead appears to offer the middle ground for both
workloads.

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Issue #5902
2017-05-04 18:00:27 -04:00
RageLtMan
5731140eaf Disable write merging on ZVOLs
The current ZVOL implementation does not explicitly set merge
options on ZVOL device queues, which results in the default merge
behavior.

Explicitly set QUEUE_FLAG_NOMERGES on ZVOL queues allowing the
ZIO pipeline to do its work.

Initial benchmarks (tiotest with no O_DIRECT) show random write
performance going up almost 3X on 8K ZVOLs, even after significant
rewrites of the logical space allocation.

Reviewed-by: Richard Yao <ryao@gentoo.org>
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: RageLtMan <rageltman@sempervictus>
Issue #5902
2017-05-04 17:59:52 -04:00
Chunwei Chen
692e55b8fe Reinstate zvol_taskq to fix aio on zvol
Commit 37f9dac removed the zvol_taskq for processing zvol requests.
This was removed as part of switching to make_request_fn and was
motivated by a concern at the time over dispatch latency.

However, this also made all bio request synchronous, and caused
serious performance issues as the bio submitter would wait for
every bio it submitted, effectively making the IO depth 1.

This patch reinstate zvol_taskq, and to make sure overlapped I/Os
are ordered properly, we take range lock in zvol_request, and pass
it along with bio to the I/O functions zvol_{write,discard,read}.

In order to facilitate benchmarks a zvol_request_sync module
option was added to switch between sync and async request handling.
For the moment, the default behavior is synchronous but this is
likely to change pending additional testing.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #5824
2017-04-26 13:54:40 -07:00
Brian Behlendorf
ef1bdf363c Fix ZVOL BLKFLSBUF ioctl
The BLKFLSBUF ioctl is expected to do two things:

  - flush dirty pages to stable storage, and
  - invalidate clean pages

Unfortunately, the existing implementation of BLKFLSBUF in
zvol_ioctl() only flushes pages which are part of the current
TXG to disk.  There may be additional dirty pages in the
page cache which haven't yet been submitted to the DMU and
therefore aren't part of any TXG.

Furthermore because zvol_ioctl() returns 0 the generic
blkdev_flushbuf() does not invalidate the page cache.

Resolve the issue by moving bdev_flush() in to zvol_ioctl()
and explicitly waiting for a full TXG sync.  Then invalidate
the page cache.  The associated ARC buffers need not be
evicted since they cannot be bypassed using O_DIRECT.

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #5871 
Closes #5879
2017-03-09 17:43:36 -08:00
Matthew Ahrens
4a5d7f8267 Allow c99 code to compile
Add the appropriate compiler flags to accept c99 code.  This will help to
minimize differences with upstream, and aid porting changes.  One change was
necessary in zvol.c because the DEFINE_IDA() macro does not work with the new
compiler flags.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #5756
2017-02-08 09:27:48 -08:00
George Melikov
4ea3f86426 codebase style improvements for OpenZFS 6459 port 2017-01-22 13:25:40 -08:00