Commit Graph

68 Commits

Author SHA1 Message Date
Matthew Ahrens
cb9e5b7e84 dn_struct_rwlock can not be held in dmu_tx_try_assign()
The thread calling dmu_tx_try_assign() can't hold the dn_struct_rwlock
while assigning the tx, because this can lead to deadlock. Specifically,
if this dnode is already assigned to an earlier txg, this thread may
need to wait for that txg to sync (the ERESTART case below).  The other
thread that has assigned this dnode to an earlier txg prevents this txg
from syncing until its tx can complete (calling dmu_tx_commit()), but it
may need to acquire the dn_struct_rwlock to do so (e.g. via
dmu_buf_hold*()).

This commit adds an assertion to dmu_tx_try_assign() to ensure that this
deadlock is not inadvertently introduced.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #8929
2019-06-22 16:48:54 -07:00
Tim Schumacher
424fd7c3e0 Prefix all refcount functions with zfs_
Recent changes in the Linux kernel made it necessary to prefix
the refcount_add() function with zfs_ due to a name collision.

To bring the other functions in line with that and to avoid future
collisions, prefix the other refcount functions as well.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Closes #7963
2018-10-01 10:42:05 -07:00
Tim Schumacher
c13060e478 Linux 4.19-rc3+ compat: Remove refcount_t compat
torvalds/linux@59b57717f ("blkcg: delay blkg destruction until
after writeback has finished") added a refcount_t to the blkcg
structure. Due to the refcount_t compatibility code, zfs_refcount_t
was used by mistake.

Resolve this by removing the compatibility code and replacing the
occurrences of refcount_t with zfs_refcount_t.

Reviewed-by: Franz Pletz <fpletz@fnordicwalking.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Closes #7885 
Closes #7932
2018-09-26 10:29:26 -07:00
Tom Caputi
8c4fb36a24 Small rework of txg_list code
This patch simply adds some missing locking to the txg_list
functions and refactors txg_verify() so that it is only compiled
in for debug builds.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #7795
2018-08-27 10:16:01 -07:00
Feng Sun
750e1f88d3 Introduce kstat dmu_tx_dirty_frees_delay
It is helpful to tune zfs_per_txg_dirty_frees_percent for commit
539d33c7(OpenZFS 6569 - large file delete can starve out write ops).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Feng Sun <loyou85@gmail.com>
Closes #7718
2018-07-25 09:52:27 -07:00
Serapheim Dimitropoulos
e48afbc4eb OpenZFS 9464 - txg_kick() fails to see that we are quiescing
txg_kick() fails to see that we are quiescing, forcing transactions to
their next stages without leaving them accumulate changes

Creating a fragmented pool in a DCenter VM and continuously writing to it with
multiple instances of randwritecomp, we get the following output from txg.d:

    0ms   311MB in  4114ms (95% p1)  75MB/s  544MB (76%)  336us   153ms     0ms
    0ms     8MB in    51ms ( 0% p1) 163MB/s  474MB (66%)  129us    34ms     0ms
    0ms   366MB in  4454ms (93% p1)  82MB/s  572MB (79%)  498us    20ms     0ms
    0ms   406MB in  5212ms (95% p1)  77MB/s  591MB (82%)  661us    37ms     0ms
    0ms   340MB in  5110ms (94% p1)  66MB/s  622MB (86%) 1048us    41ms     1ms
    0ms     3MB in    61ms ( 0% p1)  51MB/s  419MB (58%)   33us     0ms     0ms
    0ms   361MB in  3555ms (88% p1) 101MB/s  542MB (75%)  335us    40ms     0ms
    0ms   356MB in  4592ms (92% p1)  77MB/s  561MB (78%)  430us    89ms     1ms
    0ms    11MB in   129ms (13% p1)  90MB/s  507MB (70%)  222us    15ms     0ms
    0ms   281MB in  2520ms (89% p1) 111MB/s  542MB (75%)  334us    42ms     0ms
    0ms   383MB in  3666ms (91% p1) 104MB/s  557MB (77%)  411us   133ms     0ms
    0ms   404MB in  5757ms (94% p1)  70MB/s  635MB (88%) 1274us   123ms     2ms
    4ms   367MB in  4172ms (89% p1)  88MB/s  556MB (77%)  401us    51ms     0ms
    0ms    42MB in   470ms (44% p1)  90MB/s  557MB (77%)  412us    43ms     0ms
    0ms   261MB in  2273ms (88% p1) 114MB/s  556MB (77%)  407us    27ms     0ms
    0ms   394MB in  3646ms (85% p1) 108MB/s  552MB (77%)  393us   304ms     0ms
    0ms   275MB in  2416ms (89% p1) 113MB/s  510MB (71%)  200us    53ms     0ms
    0ms     9MB in    53ms ( 0% p1) 169MB/s  483MB (67%)  140us   100ms     1ms

The TXGs that are getting synced and don't have lots of changes are pushed by
txg_kick() which basically forces the current open txg to get to the quiesced
state:

        if (tx->tx_syncing_txg == 0 &&
        tx->tx_quiesce_txg_waiting <= tx->tx_open_txg &&
        tx->tx_sync_txg_waiting <= tx->tx_synced_txg &&
        tx->tx_quiesced_txg <= tx->tx_synced_txg) {
        tx->tx_quiesce_txg_waiting = tx->tx_open_txg + 1;
        cv_broadcast(&tx->tx_quiesce_more_cv);
    }

The problem is that the above code doesn't check if we are currently quiescing
anything (only if a quiesce or a sync has been requested, ..etc) so the
following scenario can happen:

1] We have an open txg A that had enough dirty data (more than
   zfs_dirty_data_sync) and it was pushed to the quiesced state, and opened
   a new txg B. No txg is currently being synced.
2] Immediately after the opening of B, txg_kick() was run by some other write
   (and because of A's dirty data) and saw that we are not currently syncing
   any txg and no one has requested quiescing so it requests one by bumping
   tx_quiesce_txg_waiting and broadcasts the quiesce thread.
3] The quiesce thread just passed txg A to be synced and sees that a quiescing
   request has been sent to it so it immediately grabs B without letting it
   gather enough data, putting it in a quiesced state and opening a new txg C.

In this scenario txg B, is an example of how the entries of interest show up in
the txg.d output.

Ideally we would like txg_kick() to get triggered only when we are sure that
we are not syncing AND not quiescing any txg. This way we can kick an open TXG
to the quiescing state when we are sure that there is nothing going on and we
would benefit from the different states running concurrently.

Authored by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://illumos.org/issues/9464
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/1cd7635b
Closes #7587
2018-06-04 14:56:06 -07:00
Brian Behlendorf
93ce2b4ca5 Update build system and packaging
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
2018-05-29 16:00:33 -07:00
Matthew Ahrens
a1d477c24c OpenZFS 7614, 9064 - zfs device evacuation/removal
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/f539f1eb
Closes #6900
2018-04-14 12:16:17 -07:00
Prakash Surya
0735ecb334 OpenZFS 8997 - ztest assertion failure in zil_lwb_write_issue
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/19ea6cb0f9
Closes #7084
2018-01-26 20:19:46 -08:00
lidongyang
823d48bfb1 Call commit callbacks from the tail of the list
Our zfs backed Lustre MDT had soft lockups while under heavy metadata
workloads while handling transaction callbacks from osd_zfs.

The problem is zfs is not taking advantage of the fast path in
Lustre's trans callback handling, where Lustre will skip the calls
to ptlrpc_commit_replies() when it already saw a higher transaction
number.

This patch corrects this, it also has a positive impact on metadata
performance on Lustre with osd_zfs, plus some cleanup in the headers.

A similar issue for ext4/ldiskfs is described on:
https://jira.hpdd.intel.com/browse/LU-6527

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Li Dongyang <dongyang.li@anu.edu.au>
Closes #6986
2017-12-22 10:19:51 -08:00
Don Brady
1c27024e22 Undo c89 workarounds to match with upstream
With PR 5756 the zfs module now supports c99 and the
remaining past c89 workarounds can be undone.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Don Brady <don.brady@delphix.com>
Closes #6816
2017-11-04 13:25:13 -07:00
Brian Behlendorf
848259c10f Export symbol dmu_tx_mark_netfree()
This symbol is needed by Lustre for the same reason it was needed
by the ZPL.  It should have been exported when the original patch
was merged.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6660
2017-09-20 09:30:24 -07:00
Brian Behlendorf
9631681b75 Fix dnode allocation race
When performing concurrent object allocations using the new
multi-threaded allocator and large dnodes it's possible to
allocate overlapping large dnodes.

This case should have been handled by detecting an error
returned by dnode_hold_impl().  But that logic only checked
the returned dnp was not-NULL, and the dnp variable was not
reset to NULL when retrying.  Resolve this issue by properly
checking the return value of dnode_hold_impl().

Additionally, it was possible that dnode_hold_impl() would
misreport a dnode as free when it was in fact in use.  This
could occurs for two reasons:

* The per-slot zrl_lock must be held over the entire critical
  section which includes the alloc/free until the new dnode
  is assigned to children_dnodes.  Additionally, all of the
  zrl_lock's in the range must be held to protect moving
  dnodes.

* The dn->dn_ot_type cannot be solely relied upon to check
  the type.  When allocating a new dnode its type will be
  DMU_OT_NONE after dnode_create().  Only latter when
  dnode_allocate() is called will it transition to the new
  type.  This means there's a window when allocating where
  it can mistaken for a free dnode.

Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Ned Bass <bass6@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6414 
Closes #6439
2017-08-08 08:38:53 -07:00
Ned Bass
ecb2b7dc7f Use SET_ERROR for constant non-zero return codes
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
2017-08-02 21:16:12 -07:00
Matthew Ahrens
4747a7d3d4 OpenZFS 8063 - verify that we do not attempt to access inactive txg
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>

A standard practice in ZFS is to keep track of "per-txg" state. Any of
the 3 active TXG's (open, quiescing, syncing) can have different values
for this state. We should assert that we do not attempt to modify other
(inactive) TXG's.

Porting Notes:
- ASSERTV added to txg_sync_waiting() for unused variable.

OpenZFS-issue: https://www.illumos.org/issues/8063
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/01acb46
Closes #6109
2017-05-10 13:52:22 -04:00
Matthew Ahrens
9522bd2429 OpenZFS 7801 - add more by-dnode routines (lint)
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Giuseppe Di Natale <dinatale2@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/7801
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f25efb3
Closes #5894
2017-03-20 12:33:17 -07:00
Brian Behlendorf
3ec3bc2167 OpenZFS 7793 - ztest fails assertion in dmu_tx_willuse_space
Reviewed by: Steve Gonczi <steve.gonczi@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

Background information: This assertion about tx_space_* verifies that we
are not dirtying more stuff than we thought we would. We “need” to know
how much we will dirty so that we can check if we should fail this
transaction with ENOSPC/EDQUOT, in dmu_tx_assign(). While the
transaction is open (i.e. between dmu_tx_assign() and dmu_tx_commit() —
typically less than a millisecond), we call dbuf_dirty() on the exact
blocks that will be modified. Once this happens, the temporary
accounting in tx_space_* is unnecessary, because we know exactly what
blocks are newly dirtied; we call dnode_willuse_space() to track this
more exact accounting.

The fundamental problem causing this bug is that dmu_tx_hold_*() relies
on the current state in the DMU (e.g. dn_nlevels) to predict how much
will be dirtied by this transaction, but this state can change before we
actually perform the transaction (i.e. call dbuf_dirty()).

This bug will be fixed by removing the assertion that the tx_space_*
accounting is perfectly accurate (i.e. we never dirty more than was
predicted by dmu_tx_hold_*()). By removing the requirement that this
accounting be perfectly accurate, we can also vastly simplify it, e.g.
removing most of the logic in dmu_tx_count_*().

The new tx space accounting will be very approximate, and may be more or
less than what is actually dirtied. It will still be used to determine
if this transaction will put us over quota. Transactions that are marked
by dmu_tx_mark_netfree() will be excepted from this check. We won’t make
an attempt to determine how much space will be freed by the transaction
— this was rarely accurate enough to determine if a transaction should
be permitted when we are over quota, which is why dmu_tx_mark_netfree()
was introduced in 2014.

We also won’t attempt to give “credit” when overwriting existing blocks,
if those blocks may be freed. This allows us to remove the
do_free_accounting logic in dbuf_dirty(), and associated routines. This
logic attempted to predict what will be on disk when this txg syncs, to
know if the overwritten block will be freed (i.e. exists, and has no
snapshots).

OpenZFS-issue: https://www.illumos.org/issues/7793
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3704e0a
Upstream bugs: DLPX-32883a
Closes #5804 

Porting notes:
- DNODE_SIZE replaced with DNODE_MIN_SIZE in dmu_tx_count_dnode(),
  Using the default dnode size would be slightly better.
- DEBUG_DMU_TX wrappers and configure option removed.
- Resolved _by_dnode() conflicts these changes have not yet been
  applied to OpenZFS.
2017-03-07 09:51:59 -08:00
Matthew Ahrens
66eead53c9 Clean up by-dnode code in dmu_tx.c
0eef1bde31
introduced some changes which we slightly improved the style of when
porting to illumos.

There is also one minor error-handling fix, in zap_add() the "zap" may
become NULL in case of an error re-opening the ZAP.

Originally suggested at: https://github.com/openzfs/openzfs/pull/276

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #5805
2017-02-24 13:34:26 -08:00
George Melikov
f85c06bedf OpenZFS 7054 - dmu_tx_hold_t should use refcount_t to track space
Authored by: Igor Kozhukhov ikozhukhov@gmail.com
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov mail@gmelikov.ru

OpenZFS-issue: https://www.illumos.org/issues/7054
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0c779ad
Closes #5600
2017-01-23 09:36:24 -08:00
bzzz77
0eef1bde31 Add *_by-dnode routines
Add *_by_dnode() routines for accessing objects given their
dnode_t *, this is more efficient than accessing the object by 
(objset_t *, uint64_t object).  This change converts some but
not all of the existing consumers.  As performance-sensitive
code paths are discovered they should be converted to use
these routines.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Closes #5534 
Issue #4802
2017-01-13 14:58:41 -08:00
cao
f4bae2ed63 Fix coverity defects: CID 147575, 147577, 147578, 147579
CID 147575, Type:Unintentional integer overflow
CID 147577, Type:Unintentional integer overflow
CID 147578, Type:Unintentional integer overflow
CID 147579, Type:Unintentional integer overflow

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: cao.xuewen <cao.xuewen@zte.com.cn>
Closes #5365
2016-11-07 14:54:32 -08:00
cao
981b21260e Fix coverity defects: CID 147553
CID 147553: Type:Dereference null return value

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: cao.xuewen <cao.xuewen@zte.com.cn>
Closes #5305
2016-11-01 10:20:24 -07:00
luozhengzheng
05852b3467 Fix coverity defects: CID 147571, 147574
CID 147571: Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
CID 147574: Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: luozhengzheng <luo.zhengzheng@zte.com.cn>
Closes #5268
2016-10-13 14:25:05 -07:00
Matthew Ahrens
2bce8049c3 OpenZFS 7004 - dmu_tx_hold_zap() does dnode_hold() 7x on same object
Using a benchmark which has 32 threads creating 2 million files in the
same directory, on a machine with 16 CPU cores, I observed poor
performance. I noticed that dmu_tx_hold_zap() was using about 30% of
all CPU, and doing dnode_hold() 7 times on the same object (the ZAP
object that is being held).

dmu_tx_hold_zap() keeps a hold on the dnode_t the entire time it is
running, in dmu_tx_hold_t:txh_dnode, so it would be nice to use the
dnode_t that we already have in hand, rather than repeatedly calling
dnode_hold(). To do this, we need to pass the dnode_t down through
all the intermediate calls that dmu_tx_hold_zap() makes, making these
routines take the dnode_t* rather than an objset_t* and a uint64_t
object number. In particular, the following routines will need to have
analogous *_by_dnode() variants created:

dmu_buf_hold_noread()
dmu_buf_hold()
zap_lookup()
zap_lookup_norm()
zap_count_write()
zap_lockdir()
zap_count_write()

This can improve performance on the benchmark described above by 100%,
from 30,000 file creations per second to 60,000. (This improvement is on
top of that provided by working around the object allocation issue. Peak
performance of ~90,000 creations per second was observed with 8 CPUs;
adding CPUs past that decreased performance due to lock contention.) The
CPU used by dmu_tx_hold_zap() was reduced by 88%, from 340 CPU-seconds
to 40 CPU-seconds.

Sponsored by: Intel Corp.

Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/7004
OpenZFS-commit: https://github.com/openzfs/openzfs/pull/109
Closes #4641
Closes #4972
2016-08-19 12:48:03 -07:00
Ned Bass
50c957f702 Implement large_dnode pool feature
Justification
-------------

This feature adds support for variable length dnodes. Our motivation is
to eliminate the overhead associated with using spill blocks.  Spill
blocks are used to store system attribute data (i.e. file metadata) that
does not fit in the dnode's bonus buffer. By allowing a larger bonus
buffer area the use of a spill block can be avoided.  Spill blocks
potentially incur an additional read I/O for every dnode in a dnode
block. As a worst case example, reading 32 dnodes from a 16k dnode block
and all of the spill blocks could issue 33 separate reads. Now suppose
those dnodes have size 1024 and therefore don't need spill blocks.  Then
the worst case number of blocks read is reduced to from 33 to two--one
per dnode block. In practice spill blocks may tend to be co-located on
disk with the dnode blocks so the reduction in I/O would not be this
drastic. In a badly fragmented pool, however, the improvement could be
significant.

ZFS-on-Linux systems that make heavy use of extended attributes would
benefit from this feature. In particular, ZFS-on-Linux supports the
xattr=sa dataset property which allows file extended attribute data
to be stored in the dnode bonus buffer as an alternative to the
traditional directory-based format. Workloads such as SELinux and the
Lustre distributed filesystem often store enough xattr data to force
spill bocks when xattr=sa is in effect. Large dnodes may therefore
provide a performance benefit to such systems.

Other use cases that may benefit from this feature include files with
large ACLs and symbolic links with long target names. Furthermore,
this feature may be desirable on other platforms in case future
applications or features are developed that could make use of a
larger bonus buffer area.

Implementation
--------------

The size of a dnode may be a multiple of 512 bytes up to the size of
a dnode block (currently 16384 bytes). A dn_extra_slots field was
added to the current on-disk dnode_phys_t structure to describe the
size of the physical dnode on disk. The 8 bits for this field were
taken from the zero filled dn_pad2 field. The field represents how
many "extra" dnode_phys_t slots a dnode consumes in its dnode block.
This convention results in a value of 0 for 512 byte dnodes which
preserves on-disk format compatibility with older software.

Similarly, the in-memory dnode_t structure has a new dn_num_slots field
to represent the total number of dnode_phys_t slots consumed on disk.
Thus dn->dn_num_slots is 1 greater than the corresponding
dnp->dn_extra_slots. This difference in convention was adopted
because, unlike on-disk structures, backward compatibility is not a
concern for in-memory objects, so we used a more natural way to
represent size for a dnode_t.

The default size for newly created dnodes is determined by the value of
a new "dnodesize" dataset property. By default the property is set to
"legacy" which is compatible with older software. Setting the property
to "auto" will allow the filesystem to choose the most suitable dnode
size. Currently this just sets the default dnode size to 1k, but future
code improvements could dynamically choose a size based on observed
workload patterns. Dnodes of varying sizes can coexist within the same
dataset and even within the same dnode block. For example, to enable
automatically-sized dnodes, run

 # zfs set dnodesize=auto tank/fish

The user can also specify literal values for the dnodesize property.
These are currently limited to powers of two from 1k to 16k. The
power-of-2 limitation is only for simplicity of the user interface.
Internally the implementation can handle any multiple of 512 up to 16k,
and consumers of the DMU API can specify any legal dnode value.

The size of a new dnode is determined at object allocation time and
stored as a new field in the znode in-memory structure. New DMU
interfaces are added to allow the consumer to specify the dnode size
that a newly allocated object should use. Existing interfaces are
unchanged to avoid having to update every call site and to preserve
compatibility with external consumers such as Lustre. The new
interfaces names are given below. The versions of these functions that
don't take a dnodesize parameter now just call the _dnsize() versions
with a dnodesize of 0, which means use the legacy dnode size.

New DMU interfaces:
  dmu_object_alloc_dnsize()
  dmu_object_claim_dnsize()
  dmu_object_reclaim_dnsize()

New ZAP interfaces:
  zap_create_dnsize()
  zap_create_norm_dnsize()
  zap_create_flags_dnsize()
  zap_create_claim_norm_dnsize()
  zap_create_link_dnsize()

The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The
spa_maxdnodesize() function should be used to determine the maximum
bonus length for a pool.

These are a few noteworthy changes to key functions:

* The prototype for dnode_hold_impl() now takes a "slots" parameter.
  When the DNODE_MUST_BE_FREE flag is set, this parameter is used to
  ensure the hole at the specified object offset is large enough to
  hold the dnode being created. The slots parameter is also used
  to ensure a dnode does not span multiple dnode blocks. In both of
  these cases, if a failure occurs, ENOSPC is returned. Keep in mind,
  these failure cases are only possible when using DNODE_MUST_BE_FREE.

  If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0.
  dnode_hold_impl() will check if the requested dnode is already
  consumed as an extra dnode slot by an large dnode, in which case
  it returns ENOENT.

* The function dmu_object_alloc() advances to the next dnode block
  if dnode_hold_impl() returns an error for a requested object.
  This is because the beginning of the next dnode block is the only
  location it can safely assume to either be a hole or a valid
  starting point for a dnode.

* dnode_next_offset_level() and other functions that iterate
  through dnode blocks may no longer use a simple array indexing
  scheme. These now use the current dnode's dn_num_slots field to
  advance to the next dnode in the block. This is to ensure we
  properly skip the current dnode's bonus area and don't interpret it
  as a valid dnode.

zdb
---
The zdb command was updated to display a dnode's size under the
"dnsize" column when the object is dumped.

For ZIL create log records, zdb will now display the slot count for
the object.

ztest
-----
Ztest chooses a random dnodesize for every newly created object. The
random distribution is more heavily weighted toward small dnodes to
better simulate real-world datasets.

Unused bonus buffer space is filled with non-zero values computed from
the object number, dataset id, offset, and generation number.  This
helps ensure that the dnode traversal code properly skips the interior
regions of large dnodes, and that these interior regions are not
overwritten by data belonging to other dnodes. A new test visits each
object in a dataset. It verifies that the actual dnode size matches what
was stored in the ztest block tag when it was created. It also verifies
that the unused bonus buffer space is filled with the expected data
patterns.

ZFS Test Suite
--------------
Added six new large dnode-specific tests, and integrated the dnodesize
property into existing tests for zfs allow and send/recv.

Send/Receive
------------
ZFS send streams for datasets containing large dnodes cannot be received
on pools that don't support the large_dnode feature. A send stream with
large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be
unrecognized by an incompatible receiving pool so that the zfs receive
will fail gracefully.

While not implemented here, it may be possible to generate a
backward-compatible send stream from a dataset containing large
dnodes. The implementation may be tricky, however, because the send
object record for a large dnode would need to be resized to a 512
byte dnode, possibly kicking in a spill block in the process. This
means we would need to construct a new SA layout and possibly
register it in the SA layout object. The SA layout is normally just
sent as an ordinary object record. But if we are constructing new
layouts while generating the send stream we'd have to build the SA
layout object dynamically and send it at the end of the stream.

For sending and receiving between pools that do support large dnodes,
the drr_object send record type is extended with a new field to store
the dnode slot count. This field was repurposed from unused padding
in the structure.

ZIL Replay
----------
The dnode slot count is stored in the uppermost 8 bits of the lr_foid
field. The bits were unused as the object id is currently capped at
48 bits.

Resizing Dnodes
---------------
It should be possible to resize a dnode when it is dirtied if the
current dnodesize dataset property differs from the dnode's size, but
this functionality is not currently implemented. Clearly a dnode can
only grow if there are sufficient contiguous unused slots in the
dnode block, but it should always be possible to shrink a dnode.
Growing dnodes may be useful to reduce fragmentation in a pool with
many spill blocks in use. Shrinking dnodes may be useful to allow
sending a dataset to a pool that doesn't support the large_dnode
feature.

Feature Reference Counting
--------------------------
The reference count for the large_dnode pool feature tracks the
number of datasets that have ever contained a dnode of size larger
than 512 bytes. The first time a large dnode is created in a dataset
the dataset is converted to an extensible dataset. This is a one-way
operation and the only way to decrement the feature count is to
destroy the dataset, even if the dataset no longer contains any large
dnodes. The complexity of reference counting on a per-dnode basis was
too high, so we chose to track it on a per-dataset basis similarly to
the large_block feature.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3542
2016-06-24 13:13:21 -07:00
Matthew Ahrens
19d55079ae Illumos 4950 - files sometimes can't be removed from a full filesystem
4950 files sometimes can't be removed from a full filesystem
Reviewed by: Adam Leventhal <adam.leventhal@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Boris Protopopov <bprotopopov@hotmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/4950
  https://github.com/illumos/illumos-gate/commit/4bb7380

Porting notes:
- ZoL currently does not log discards to zvols, so the portion of
  this patch that modifies the discard logging to mark it as
  freeing space has been discarded.

2. may_delete_now had been removed from zfs_remove() in ZoL.
   It has been reintroduced.

3. We do not try to emulate vnodes, so the following lines are
   not valid on Linux:

	mutex_enter(&vp->v_lock);
	may_delete_now = vp->v_count == 1 && !vn_has_cached_data(vp);
	mutex_exit(&vp->v_lock);

  This has been replaced with:

	mutex_enter(&zp->z_lock);
	may_delete_now = atomic_read(&ip->i_count) == 1 && !(zp->z_is_mapped);
	mutex_exit(&zp->z_lock);

Ported-by: Richard Yao <richard.yao@clusterhq.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2016-01-21 16:59:30 -08:00
Paul Dagnelie
fcff0f35bd Illumos 5960, 5925
5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>

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

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

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2016-01-08 15:08:19 -08:00
Matthew Ahrens
4bda3bd0e7 Illumos 5911 - ZFS "hangs" while deleting file
5911 ZFS "hangs" while deleting file
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Reviewed by: Alek Pinchuk <alek@nexenta.com>
Reviewed by: Simon Klinkert <simon.klinkert@gmail.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/5911
  https://github.com/illumos/illumos-gate/commit/46e1baa

Porting notes:

Resolved ISO C90 forbids mixed declarations and code wanting in
the dnode_free_range() function.

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3554
2015-07-06 09:31:42 -07:00
Matthew Ahrens
f1512ee61e Illumos 5027 - zfs large block support
5027 zfs large block support
Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@omniti.com>

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

Porting Notes:

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

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

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

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

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

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #354
2015-05-11 12:23:16 -07:00
Justin T. Gibbs
d683ddbb72 Illumos 5314 - Remove "dbuf phys" db->db_data pointer aliases in ZFS
5314 Remove "dbuf phys" db->db_data pointer aliases in ZFS
Author: Justin T. Gibbs <justing@spectralogic.com>
Reviewed by: Andriy Gapon <avg@freebsd.org>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Will Andrews <willa@spectralogic.com>
Approved by: Dan McDonald <danmcd@omniti.com>

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

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-04-28 16:25:20 -07:00
Tim Chase
ded576e28f Set the maximum ZVOL transfer size correctly
ZoL had been setting max_sectors to UINT_MAX, but until Linux 3.19, it
the kernel artifically capped it at 1024 (BLK_DEF_MAX_SECTORS).
This cap was removed in torvalds/linux@34b48db.  This patch changes
it to DMU_MAX_ACCESS (in sectors) and also changes the ASSERT in
dmu_tx_hold_write() to allow the maximum transfer size.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3212
2015-03-25 11:58:42 -07:00
Brian Behlendorf
989fd514b1 Change ASSERT(!"...") to cmn_err(CE_PANIC, ...)
There are a handful of ASSERT(!"...")'s throughout the code base for
cases which should be impossible.  This patch converts them to use
cmn_err(CE_PANIC, ...) to ensure they are always enabled and so that
additional debugging is logged if they were to occur.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1445
2015-03-03 13:22:21 -08:00
Brian Behlendorf
79c76d5b65 Change KM_PUSHPAGE -> KM_SLEEP
By marking DMU transaction processing contexts with PF_FSTRANS
we can revert the KM_PUSHPAGE -> KM_SLEEP changes.  This brings
us back in line with upstream.  In some cases this means simply
swapping the flags back.  For others fnvlist_alloc() was replaced
by nvlist_alloc(..., KM_PUSHPAGE) and must be reverted back to
fnvlist_alloc() which assumes KM_SLEEP.

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

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 14:41:26 -08:00
Ned Bass
49ee64e5e6 Remove duplicate typedefs from trace.h
Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate
typedef declarations with the same type. The trace.h header contains
some typedefs to avoid 'unknown type' errors for C files that haven't
declared the type in question. But this causes build failures for C
files that have already declared the type. Newer versions of GCC (e.g.
v4.6) allow duplicate typedefs with the same type unless pedantic error
checking is in force. To support the older versions we need to remove
the duplicate typedefs.

Removal of the typedefs means we can't built tracepoints code using
those types unless the required headers have been included. To
facilitate this, all tracepoint event declarations have been moved out
of trace.h into separate headers. Each new header is explicitly included
from the C file that uses the events defined therein. The trace.h header
is still indirectly included form zfs_context.h and provides the
implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces.
This makes those interfaces readily available throughout the code base.
The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also
still provided by trace.h, so it is a prerequisite for the other
trace_*.h headers.

These new Linux implementation-specific headers do introduce a small
divergence from upstream ZFS in several core C files, but this should
not present a significant maintenance burden.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2953
2015-01-06 16:53:24 -08:00
Ned Bass
a77c4c8332 Improve reporting of tx assignment wait times
Some callers of dmu_tx_assign() use the TXG_NOWAIT flag and call
dmu_tx_wait() themselves before retrying if the assignment fails.
The wait times for such callers are not accounted for in the
dmu_tx_assign kstat histogram, because the histogram only records
time spent in dmu_tx_assign().  This change moves the histogram
update to dmu_tx_wait() to properly account for all time spent there.

One downside of this approach is that it is possible to call
dmu_tx_wait() multiple times before successfully assigning a
transaction, in which case the cumulative wait time would not be
recorded.  However, this case should not often arise in practice,
because most callers currently use one of these forms:

  dmu_tx_assign(tx, TXG_WAIT);
  dmu_tx_assign(tx, waited ?  TXG_WAITED : TXG_NOWAIT);

The first form should make just one call to dmu_tx_delay() inside of
dmu_tx_assign(). The second form retries with TXG_WAITED if the first
assignment fails and incurs a delay, in which case no further waiting
is performed.  Therefore transaction delays normally occur in one
call to dmu_tx_wait() so the histogram should be fairly accurate.

Another possible downside of this approach is that the histogram will
no longer record overhead outside of dmu_tx_wait() such as in
dmu_tx_try_assign(). While I'm not aware of any reason for concern on
this point, it is conceivable that lock contention, long list
traversal, etc. could cause assignment delays that would not be
reflected in the histogram.  Therefore the histogram should strictly
be used for visibility in to the normal delay mechanisms and not as a
profiling tool for code performance.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1915
2014-03-04 12:22:24 -08:00
Ned Bass
3d920a1567 dmu_tx kstat cleanup
A few counters in the dmu_tx kstats are obsolete or no longer
bumped properly.

- The sync task restructuring commit
  13fe019870 removed the code
  that bumpted dmu_tx_quota. The counter is now bumped in two
  cases, instead of just the one case as before (after the result
  of dsl_dataset_check_quota call). The second case is where
  we check the requested reservation against the actual pool size,
  as this is an implicit quota of sorts.

- The write throttle restructuring commit
  e8b96c6007 makes dmu_tx_how and
  dmu_tx_inflight obsolete, so they are removed.

Signed-off-by: Kohsuke Kawaguchi <kk@kohsuke.org>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1914
2014-03-04 12:22:24 -08:00
Matthew Ahrens
2e7b7657cd 4188 assertion failed in dmu_tx_hold_free(): dn_datablkshift != 0
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

Refences:
  https://www.illumos.org/issues/4188
  illumos/illumos-gate@bb411a08b0

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2091
2014-01-31 10:49:34 -08:00
Matthew Ahrens
e8b96c6007 Illumos #4045 write throttle & i/o scheduler performance work
4045 zfs write throttle & i/o scheduler performance work

1. The ZFS i/o scheduler (vdev_queue.c) now divides i/os into 5 classes: sync
read, sync write, async read, async write, and scrub/resilver.  The scheduler
issues a number of concurrent i/os from each class to the device.  Once a class
has been selected, an i/o is selected from this class using either an elevator
algorithem (async, scrub classes) or FIFO (sync classes).  The number of
concurrent async write i/os is tuned dynamically based on i/o load, to achieve
good sync i/o latency when there is not a high load of writes, and good write
throughput when there is.  See the block comment in vdev_queue.c (reproduced
below) for more details.

2. The write throttle (dsl_pool_tempreserve_space() and
txg_constrain_throughput()) is rewritten to produce much more consistent delays
when under constant load.  The new write throttle is based on the amount of
dirty data, rather than guesses about future performance of the system.  When
there is a lot of dirty data, each transaction (e.g. write() syscall) will be
delayed by the same small amount.  This eliminates the "brick wall of wait"
that the old write throttle could hit, causing all transactions to wait several
seconds until the next txg opens.  One of the keys to the new write throttle is
decrementing the amount of dirty data as i/o completes, rather than at the end
of spa_sync().  Note that the write throttle is only applied once the i/o
scheduler is issuing the maximum number of outstanding async writes.  See the
block comments in dsl_pool.c and above dmu_tx_delay() (reproduced below) for
more details.

This diff has several other effects, including:

 * the commonly-tuned global variable zfs_vdev_max_pending has been removed;
use per-class zfs_vdev_*_max_active values or zfs_vdev_max_active instead.

 * the size of each txg (meaning the amount of dirty data written, and thus the
time it takes to write out) is now controlled differently.  There is no longer
an explicit time goal; the primary determinant is amount of dirty data.
Systems that are under light or medium load will now often see that a txg is
always syncing, but the impact to performance (e.g. read latency) is minimal.
Tune zfs_dirty_data_max and zfs_dirty_data_sync to control this.

 * zio_taskq_batch_pct = 75 -- Only use 75% of all CPUs for compression,
checksum, etc.  This improves latency by not allowing these CPU-intensive tasks
to consume all CPU (on machines with at least 4 CPU's; the percentage is
rounded up).

--matt

APPENDIX: problems with the current i/o scheduler

The current ZFS i/o scheduler (vdev_queue.c) is deadline based.  The problem
with this is that if there are always i/os pending, then certain classes of
i/os can see very long delays.

For example, if there are always synchronous reads outstanding, then no async
writes will be serviced until they become "past due".  One symptom of this
situation is that each pass of the txg sync takes at least several seconds
(typically 3 seconds).

If many i/os become "past due" (their deadline is in the past), then we must
service all of these overdue i/os before any new i/os.  This happens when we
enqueue a batch of async writes for the txg sync, with deadlines 2.5 seconds in
the future.  If we can't complete all the i/os in 2.5 seconds (e.g. because
there were always reads pending), then these i/os will become past due.  Now we
must service all the "async" writes (which could be hundreds of megabytes)
before we service any reads, introducing considerable latency to synchronous
i/os (reads or ZIL writes).

Notes on porting to ZFS on Linux:

- zio_t gained new members io_physdone and io_phys_children.  Because
  object caches in the Linux port call the constructor only once at
  allocation time, objects may contain residual data when retrieved
  from the cache. Therefore zio_create() was updated to zero out the two
  new fields.

- vdev_mirror_pending() relied on the depth of the per-vdev pending queue
  (vq->vq_pending_tree) to select the least-busy leaf vdev to read from.
  This tree has been replaced by vq->vq_active_tree which is now used
  for the same purpose.

- vdev_queue_init() used the value of zfs_vdev_max_pending to determine
  the number of vdev I/O buffers to pre-allocate.  That global no longer
  exists, so we instead use the sum of the *_max_active values for each of
  the five I/O classes described above.

- The Illumos implementation of dmu_tx_delay() delays a transaction by
  sleeping in condition variable embedded in the thread
  (curthread->t_delay_cv).  We do not have an equivalent CV to use in
  Linux, so this change replaced the delay logic with a wrapper called
  zfs_sleep_until(). This wrapper could be adopted upstream and in other
  downstream ports to abstract away operating system-specific delay logic.

- These tunables are added as module parameters, and descriptions added
  to the zfs-module-parameters.5 man page.

  spa_asize_inflation
  zfs_deadman_synctime_ms
  zfs_vdev_max_active
  zfs_vdev_async_write_active_min_dirty_percent
  zfs_vdev_async_write_active_max_dirty_percent
  zfs_vdev_async_read_max_active
  zfs_vdev_async_read_min_active
  zfs_vdev_async_write_max_active
  zfs_vdev_async_write_min_active
  zfs_vdev_scrub_max_active
  zfs_vdev_scrub_min_active
  zfs_vdev_sync_read_max_active
  zfs_vdev_sync_read_min_active
  zfs_vdev_sync_write_max_active
  zfs_vdev_sync_write_min_active
  zfs_dirty_data_max_percent
  zfs_delay_min_dirty_percent
  zfs_dirty_data_max_max_percent
  zfs_dirty_data_max
  zfs_dirty_data_max_max
  zfs_dirty_data_sync
  zfs_delay_scale

  The latter four have type unsigned long, whereas they are uint64_t in
  Illumos.  This accommodates Linux's module_param() supported types, but
  means they may overflow on 32-bit architectures.

  The values zfs_dirty_data_max and zfs_dirty_data_max_max are the most
  likely to overflow on 32-bit systems, since they express physical RAM
  sizes in bytes.  In fact, Illumos initializes zfs_dirty_data_max_max to
  2^32 which does overflow. To resolve that, this port instead initializes
  it in arc_init() to 25% of physical RAM, and adds the tunable
  zfs_dirty_data_max_max_percent to override that percentage.  While this
  solution doesn't completely avoid the overflow issue, it should be a
  reasonable default for most systems, and the minority of affected
  systems can work around the issue by overriding the defaults.

- Fixed reversed logic in comment above zfs_delay_scale declaration.

- Clarified comments in vdev_queue.c regarding when per-queue minimums take
  effect.

- Replaced dmu_tx_write_limit in the dmu_tx kstat file
  with dmu_tx_dirty_delay and dmu_tx_dirty_over_max.  The first counts
  how many times a transaction has been delayed because the pool dirty
  data has exceeded zfs_delay_min_dirty_percent.  The latter counts how
  many times the pool dirty data has exceeded zfs_dirty_data_max (which
  we expect to never happen).

- The original patch would have regressed the bug fixed in
  zfsonlinux/zfs@c418410, which prevented users from setting the
  zfs_vdev_aggregation_limit tuning larger than SPA_MAXBLOCKSIZE.
  A similar fix is added to vdev_queue_aggregate().

- In vdev_queue_io_to_issue(), dynamically allocate 'zio_t search' on the
  heap instead of the stack.  In Linux we can't afford such large
  structures on the stack.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Ned Bass <bass6@llnl.gov>
Reviewed by: Brendan Gregg <brendan.gregg@joyent.com>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  http://www.illumos.org/issues/4045
  illumos/illumos-gate@69962b5647

Ported-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1913
2013-12-06 09:32:43 -08:00
Matthew Ahrens
92bc214c2e Illumos #4082
4082 zfs receive gets EFBIG from dmu_tx_hold_free()
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/4082
  illumos/illumos-gate@5253393b09

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
2013-11-05 12:25:26 -08:00
Matthew Ahrens
b663a23d36 Illumos #4047
4047 panic from dbuf_free_range() from dmu_free_object() while
     doing zfs receive
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@nexenta.com>

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

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

Porting notes:

1. The exported symbol dmu_free_object() was renamed to
   dmu_free_long_object() in Illumos.
2013-11-05 12:23:35 -08:00
Matthew Ahrens
383fc4a997 Illumos #3955
3955 ztest failure: assertion refcount_count(&tx->tx_space_written) +
     delta <= tx->tx_space_towrite
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/3955
  illumos/illumos-gate@be9000cc67

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
2013-11-05 12:16:14 -08:00
Matthew Ahrens
ea97f8ce35 Illumos #3834
3834 incremental replication of 'holey' file systems is slow
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/3834
  illumos/illumos-gate@ca48f36f20

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
2013-11-05 12:15:00 -08:00
Will Andrews
e49f1e20a0 Illumos #3741
3741 zfs needs better comments
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>

References:
  https://www.illumos.org/issues/3741
  illumos/illumos-gate@3e30c24aee

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
2013-11-04 10:55:25 -08:00
Matthew Ahrens
2e528b49f8 Illumos #3598
3598 want to dtrace when errors are generated in zfs
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

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

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

Porting notes:

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

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

3. I'm NOT happy about this change.  It does nothing but ugly
   up the code under Linux.  Unfortunately we need to take it to
   avoid more merge conflicts in the future.  -Brian
2013-10-31 14:58:04 -07:00
Brian Behlendorf
2d37239a28 Add visibility in to dmu_tx_assign times
This change adds a new kstat to gain some visibility into the
amount of time spent in each call to dmu_tx_assign. A histogram
is exported via the new dmu_tx_assign file. The information
contained in this histogram is the frequency dmu_tx_assign
took to complete given an interval range.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2013-10-25 13:57:25 -07:00
Brian Behlendorf
98ab38d109 Revert "Add new kstat for monitoring time in dmu_tx_assign"
This reverts commit 92334b14ec.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2013-10-25 13:57:25 -07:00
Matthew Ahrens
13fe019870 Illumos #3464
3464 zfs synctask code needs restructuring
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

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

Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1495
2013-09-04 16:01:24 -07:00
Matthew Ahrens
6f1ffb0665 Illumos #2882, #2883, #2900
2882 implement libzfs_core
2883 changing "canmount" property to "on" should not always remount dataset
2900 "zfs snapshot" should be able to create multiple, arbitrary snapshots at once

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Chris Siden <christopher.siden@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Reviewed by: Bill Pijewski <wdp@joyent.com>
Reviewed by: Dan Kruchinin <dan.kruchinin@gmail.com>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>

References:
  https://www.illumos.org/issues/2882
  https://www.illumos.org/issues/2883
  https://www.illumos.org/issues/2900
  illumos/illumos-gate@4445fffbbb

Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1293

Porting notes:

WARNING: This patch changes the user/kernel ABI.  That means that
the zfs/zpool utilities built from master are NOT compatible with
the 0.6.2 kernel modules.  Ensure you load the matching kernel
modules from master after updating the utilities.  Otherwise the
zfs/zpool commands will be unable to interact with your pool and
you will see errors similar to the following:

  $ zpool list
  failed to read pool configuration: bad address
  no pools available

  $ zfs list
  no datasets available

Add zvol minor device creation to the new zfs_snapshot_nvl function.

Remove the logging of the "release" operation in
dsl_dataset_user_release_sync().  The logging caused a null dereference
because ds->ds_dir is zeroed in dsl_dataset_destroy_sync() and the
logging functions try to get the ds name via the dsl_dataset_name()
function. I've got no idea why this particular code would have worked
in Illumos.  This code has subsequently been completely reworked in
Illumos commit 3b2aab1 (3464 zfs synctask code needs restructuring).

Squash some "may be used uninitialized" warning/erorrs.

Fix some printf format warnings for %lld and %llu.

Apply a few spa_writeable() changes that were made to Illumos in
illumos/illumos-gate.git@cd1c8b8 as part of the 3112, 3113, 3114 and
3115 fixes.

Add a missing call to fnvlist_free(nvl) in log_internal() that was added
in Illumos to fix issue 3085 but couldn't be ported to ZoL at the time
(zfsonlinux/zfs@9e11c73) because it depended on future work.
2013-09-04 15:49:00 -07:00
Nathaniel Clark
7d63721118 dmu_tx: Fix possible NULL pointer dereference
dmu_tx_hold_object_impl can return NULL on error.  Check for this
condition prior to dereferencing pointer.  This can only occur if
the passed object was invalid or unallocated.

Signed-off-by: Nathaniel Clark <Nathaniel.Clark@misrule.us>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1610
2013-08-01 09:48:07 -07:00
Prakash Surya
92334b14ec Add new kstat for monitoring time in dmu_tx_assign
This change adds a new kstat to gain some visibility into the amount of
time spent in each call to dmu_tx_assign. A histogram is exported via
a new dmu_tx_assign_histogram-$POOLNAME file. The information contained
in this histogram is the frequency dmu_tx_assign took to complete given
an interval range. For example, given the below histogram file:

    $ cat /proc/spl/kstat/zfs/dmu_tx_assign_histogram-tank
    12 1 0x01 32 1536 19792068076691 20516481514522
    name                            type data
    1 us                            4    859
    2 us                            4    252
    4 us                            4    171
    8 us                            4    2
    16 us                           4    0
    32 us                           4    2
    64 us                           4    0
    128 us                          4    0
    256 us                          4    0
    512 us                          4    0
    1024 us                         4    0
    2048 us                         4    0
    4096 us                         4    0
    8192 us                         4    0
    16384 us                        4    0
    32768 us                        4    1
    65536 us                        4    1
    131072 us                       4    1
    262144 us                       4    4
    524288 us                       4    0
    1048576 us                      4    0
    2097152 us                      4    0
    4194304 us                      4    0
    8388608 us                      4    0
    16777216 us                     4    0
    33554432 us                     4    0
    67108864 us                     4    0
    134217728 us                    4    0
    268435456 us                    4    0
    536870912 us                    4    0
    1073741824 us                   4    0
    2147483648 us                   4    0

one can see most calls to dmu_tx_assign completed in 32us or less, but a
few outliers did not. Specifically, 4 of the calls took between 262144us
and 131072us. This information is difficult, if not impossible, to gather
without this change.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1584
2013-07-11 13:53:44 -07:00