The current code is written on top of GFS, a library with the generic
support for writing filesystems, which was ported from illumos.
Because of significant differences between illumos VFS and FreeBSD
VFS models, both the GFS and zfsctl code were heavily modified to
work on FreeBSD. Nonetheless, they still contain quite a few ugly
hacks and bugs.
This is a reimplementation of the zfsctl code where the VFS-specific
bits are written from scratch and only the code that interacts with
the rest of ZFS is reused.
Some highlights.
We use two types of nodes, static and on-demand. The static nodes
are used for permanent directories like .zfs, .zfs/snapshot, etc. The
on-demand nodes are used for ephemeral directories that act as snapshot
mount points.
Initially only static nodes are created. Their vnodes are instantiated
when they are looked up. The on-demand nodes and vnodes are instantiated
as needed and the nodes are destroyed as soon as the corresponding
vnodes are reclaimed.
We also try very hard to ensure that uncovered snapshot vnodes do not
linger. They are supposed to become inactive as soon as they are
uncovered and we try to recycle them immediately.
When a filesystem is unmounted all snapshots under .zfs are unmounted
first, then all vnodes are flushed and finally the static .zfs nodes
are destroyed.
There are some changes outside of zfsctl code too.
z_ctldir is never used directly (as it is an opaque pointer),
zfsctl_root() has to be used instead. The function returns a locked
vnode now, so it accepts a lock flags parameter. The function can
also fail now, e.g. during force unmounting, whereas previously it
was infallible.
zfsctl_root_lookup() is retired, instead of it VOP_LOOKUP() on the .zfs
vnode (obtained with zfsctl_root) is used.
Some ideas are picked from an independent work by will.
Reviewed by: asomers, smh
MFC after: 1 month
Relnotes: maybe
Differential Revision: https://reviews.freebsd.org/D7421
7504 kmem_reap hangs spa_sync and administrative tasks
illumos/illumos-gate@405a5a0f5chttps://github.com/illumos/illumos-gate/commit/405a5a0f5c3ab36cb76559467d1a62ba648bd80https://www.illumos.org/issues/7504
We see long spa_sync(). We are waiting to hold dp_config_rwlock for writer. Some
other thread holds dp_config_rwlock for reader, then calls arc_get_data_buf(),
which finds that arc_is_overflowing()==B_TRUE. So it waits (while holding
dp_config_rwlock for reader) for arc_reclaim_thread to signal arc_reclaim_waiters_cv.
Before signaling, arc_reclaim_thread does arc_kmem_reap_now(), which takes ~seconds.
Author: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
dtrace_trap() consumes page and protection faults triggered by code running
in DTrace probe context. Such faults occur with interrupts disabled and are
detected using a per-CPU flag. Regular faults cause dtrace_trap() to be
called with interrupts enabled, and nothing was ensuring that the flag was
read from the correct CPU. This may result in dtrace_trap() consuming
unrelated page and protection faults when DTrace is enabled, causing the
fault handler to return without actually having handled the fault.
Diagnosed by: Ryan Libby <rlibby@gmail.com>
MFC after: 3 days
Sponsored by: Dell EMC Isilon
7500 Simplify dbuf_free_range by removing dn_unlisted_l0_blkid
illumos/illumos-gate@653af1b809653af1b809https://www.illumos.org/issues/7500
With the integration of:
commit 0f6d88aded0d165f5954688a9b13bac76c38da84
Author: Alex Reece <alex@delphix.com>
Date: Sat Jul 26 13:40:04 2014 -0800
4873 zvol unmap calls can take a very long time for larger datasets
the dnode's dn_bufs field was changed from a list to a tree. As a result,
the dn_unlisted_l0_blkid field is no longer necessary.
Author: Stephen Blinick <stephen.blinick@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Approved by: Gordon Ross <gordon.w.ross@gmail.com>
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
* In zfs_freebsd_setattr, if the caller wants to set the birthtime,
set the bits that zfs_settattr expects
* In zfs_setattr, if XAT_CREATETIME is set, set xoa_createtime,
expected by zfs_xvattr_set. The two levels of indirection seem
excessive, but it minimizes diffs vs OpenZFS.
* In zfs_setattr, check for overflow of va_birthtime (from delphij)
* Remove red herring in zfs_getattr
sys/cddl/contrib/opensolaris/uts/common/sys/vnode.h
* Un-booby-trap some macros
New tests are under review at https://github.com/pjd/pjdfstest/pull/6
Reviewed by: avg
MFC after: 3 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D9353
It is an ASCII encoding of a hexadecimal representation of the DOF file
used to enable anonymous tracing, so its length should always be even.
MFC after: 1 week
When recording probe site addresses in the output DOF file, dtrace -G
needs to emit relocations for the .SUNW_dof section in order to obtain
the addresses of functions containing probe sites. DTrace expects the
addresses to be relative to the base address of the final ELF file,
and the amd64 USDT implementation was relying on some unspecified and
incorrect behaviour in the base system GNU ld to achieve this.
This change reimplements the probe site relocation handling to allow
USDT to be used with lld and newer GNU binutils. Specifically, it
makes use of R_X86_64_PC64/R_386_PC32 relocations to obtain the
probe site address relative to the DOF file address, and adds and uses a
new DOF relocation type which computes the final probe site address using
these relative offsets.
Reported by and discussed with: Rafael Espíndola
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D9374
low-quality random numbers with a modern implementation (xoroshiro128+)
that is capable of generating better quality randomness without compromising performance.
Submitted by: Graeme Jenkinson
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9051
This corresponds to the following illumos issues:
5755 want support for Intel FMA instrs
5756 want support for Intel BMI1 instrs
5757 want support for Intel BMI2 instrs
5758 want support for Intel AVX2 instrs
7204 Want broadwell rdseed and adx support
7208 Want stac/clac disasm support
7733 Need SHA Instruction dis support
7756 dis can't handle x86 SSE 3 instructions
7757 want avx2 disasm tests
7758 want SSE 4.1 disasm tests
MFC after: 2 weeks
FASTTRAP_MAX_INSTR_SIZE is the largest valid value of a tracepoint, so
correct the assertion accordingly. This limit was hit with a 15-byte NOP.
Reported by: bdrewery
MFC after: 1 week
Sponsored by: Dell EMC Isilon
This ioctl has been considered legacy by upstream since the DTrace code
was first imported, and is unused. The removal also allows some
simplification of dtrace_helper_slurp().
Also remove a bogus copyout in the DTRACEHIOC_ADDDOF handler. Due to a
bug, it would overwrite an in-memory copy of the DOF header rather than
the passed-in DOF helper. Moreover, DTRACEHIOC_ADDDOF already copies the
helper back out automatically since its argument has the IOC_OUT attribute.
6569 large file delete can starve out write ops
illumos/illumos-gate@ff5177ee8bff5177ee8bhttps://www.illumos.org/issues/6569
The core issue I've found is that there is no throttle for how many
deletes get assigned to one TXG. As a results when deleting large files
we end up filling consecutive TXGs with deletes/frees, then write
throttling other (more important) ops.
There is an easy test case for this problem. Try deleting several
large files (at least 1/2 TB) while you do write ops on the same
pool. What we've seen is performance of these write ops (let's
call it sideload I/O) would drop to zero.
More specifically the problem is that dmu_free_long_range_impl()
can/will fill up all of the dirty data in the pool "instantly",
before many of the sideload ops can get in. So sideload
performance will be impacted until all the files are freed.
The solution we have tested at Nexenta (with positive results)
creates a relatively simple throttle for how many "free" ops we let
into one TXG.
However this solution exposes other problems that should also be
addressed. If we are to slow down freeing of data that means one
has to wait even longer (assuming vnode ref count of 1) to get shell
back after an rm or for NFS thread to finish the free-ing op.
To avoid this the proposed solution is to call zfs_inactive() async
for "large" files. Async freeing then begs for the reclaimed space
to be accounted for in the zpool's "freeing" prop.
The other issue with having a longer delete is the inability to
export/unmount for a longer period of time. The proposed solution
is to interrupt freeing of blocks when a fs is unmounted.
Author: Alek Pinchuk <alek@nexenta.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Sanjay Nadkarni <sanjay.nadkarni@nexenta.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Reviewed by: avg
Differential Revision: D9008
the fifth argument to functions being traced, however there was an error
where the userspace stack was being used. This may be invalid leading to
a kernel panic if this address is unmapped.
Submitted by: Graeme Jenkinson <graeme.jenkinson@cl.cam.ac.uk>
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D9229
It was a temporary change to ease an import of native atomic_cas primitives.
Instead, atomic_fcmpset was devised with different semantics. See r311168.
At least on FreeBSD there are no legal way to access media or get its
size without opening device/provider first. Postponing this caching
allows to skip several disk seeks per ZVOL/snapshot during import.
For HDD pool with 1 ZVOL in dev mode with 1000 snapshots this reduces
pool import time from 40 to 10 seconds.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
These functions may be called in DTrace probe context, so they cannot be
safely traced. Moreover, they are currently only used by DTrace, so their
corresponding FBT probes are not particularly useful.
MFC after: 2 weeks
Original commit "7090 zfs should improve allocation order" declares alloc
queue sorted by time and offset. But in practice io_offset is always zero,
so sorting happened only by time, while order of writes with equal time was
completely random. On Illumos this did not affected much thanks to using
high resolution timestamps. On FreeBSD due to using much faster but low
resolution timestamps it caused bad data placement on disks, affecting
further read performance.
This change switches zio_timestamp_compare() from comparing uninitialized
io_offset to really populated io_bookmark values. I haven't decided yet
what to do with timestampts, but on simple tests this change gives the
same peformance results by just making code to work as declared.
MFC after: 1 week
On FreeBSD the sense of rw_write_held() and rw_iswriter() were reversed,
probably due to a cut and paste error. Using rw_iswriter() would cause
the kernel to panic.
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D8718
Note: there was a merge conflict resolved by me.
illumos/illumos-gate@43297f973a43297f973ahttps://www.illumos.org/issues/3821
We recently had nodes with some of the latest zfs bits panic on us in a
rollback-heavy environment. The following is from my preliminary analysis:
Let's look at where we died:
> $C
ffffff01ea6b9a10 taskq_dispatch+0x3a(0, fffffffff7d20450, ffffff5551dea920, 1)
ffffff01ea6b9a60 zil_clean+0xce(ffffff4b7106c080, 7e0f1)
ffffff01ea6b9aa0 dsl_pool_sync_done+0x47(ffffff4313065680, 7e0f1)
ffffff01ea6b9b70 spa_sync+0x55f(ffffff4310c1d040, 7e0f1)
ffffff01ea6b9c20 txg_sync_thread+0x20f(ffffff4313065680)
ffffff01ea6b9c30 thread_start+8()
If we dig in we can find that this dataset corresponds to a zone:
> ffffff4b7106c080::print zilog_t zl_os->os_dsl_dataset->ds_dir->dd_myname
zl_os->os_dsl_dataset->ds_dir->dd_myname = [ "8ffce16a-13c2-4efa-a233-
9e378e89877b" ]
Okay so we have a null taskq pointer. That only happens during the calls to
zil_open and zil_close. If we poke around we can see that we're actually in
midst of a rollback:
> ::pgrep zfs | ::printf "0x%x %s\\n" proc_t . p_user.u_psargs
0xffffff43262800a0 zfs rollback zones/15714eb6-f5ea-469f-ac6d-
4b8ab06213c2@marlin_init
0xffffff54e22a1028 zfs rollback zones/8ffce16a-13c2-4efa-a233-
9e378e89877b@marlin_init
0xffffff4362f3a058 zfs rollback zones/0ddb8e49-ca7e-42e1-8fdc-
4ac4ba8fe9f8@marlin_init
0xffffff5748e8d020 zfs rollback zones/426357b5-832d-4430-953e-
10cd45ff8e9f@marlin_init
0xffffff436b867008 zfs rollback zones/8f36bf37-8a9c-4a44-995c-
6d1b2751e6f5@marlin_init
0xffffff4381ad4090 zfs rollback zones/6c8eca18-fbd6-46dd-ac24-
2ed45cd0da70@marlin_init
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: George Wilson <george.wilson@delphix.com>
MFC after: 3 weeks
illumos/illumos-gate@90f2c094b390f2c094b3https://www.illumos.org/issues/7181
zfsvfs_setup() is called in both zfs_mount and zfs_resume_fs paths.
dmu_objset_set_user(zfsvfs->z_os, zfsvfs) is called early in zfsvfs_setup()
before the setup is actually completed,
thus an under-constructed zfsvfs becomes visible.
Additionally, there is nothing to serialize the two call paths. As a result two
threads can step on each other's toes.
assertion failed: zilog->zl_clean_taskq == NULL, file:
../../common/fs/zfs/zil.c, line: 1772
> $c
vpanic()
0xfffffffffbdf6928()
zil_open+0x45(ffffff1bbc5dd000, fffffffff7993880)
zfsvfs_setup+0x84(ffffffb378d77000, 0)
zfs_resume_fs+0x132(ffffffb378d77000, ffffffb37ddcf000)
zfs_ioc_rollback+0x96(ffffffb37ddcf000, ffffff01dcdc4cd0, ffffff01aa091000)
zfsdev_ioctl+0x215(10a00000000, 5a19, 80465f8, 100003, ffffff01ab318368,
ffffff0004b59e58)
cdev_ioctl+0x39(10a00000000, 5a19, 80465f8, 100003, ffffff01ab318368,
ffffff0004b59e58)
spec_ioctl+0x60(ffffff0197737700, 5a19, 80465f8, 100003,
ffffff01ab318368, ffffff0004b59e58)
fop_ioctl+0x55(ffffff0197737700, 5a19, 80465f8, 100003,
ffffff01ab318368, ffffff0004b59e58)
ioctl+0x9b(7, 5a19, 80465f8)
sys_syscall32+0x1f7()
> ffffff1bbc5dd000::print objset_t os_zil
os_zil = 0xffffff1c053cf7c0
> 0xffffff1c053cf7c0::print zilog_t zl_clean_taskq
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Gordon Ross <gordon.w.ross@gmail.com>
Author: Andriy Gapon <andriy.gapon@clusterhq.com>
MFC after: 2 weeks
already free blocks
7199 dsl_dataset_rollback_sync may try to free already free blocks
7200 no blocks must be born in a txg after a snaphot is created
illumos/illumos-gate@bfaed0b91ebfaed0b91ehttps://www.illumos.org/issues/7199
dsl_dataset_rollback_sync may try to free already freed blocks when it calls
dsl_destroy_head_sync_impl to destroy a temporary clone.
That happens if a snapshot to which we are rolling back and from which the
clone is created has some ZIL records.
https://www.illumos.org/issues/7200
No new blocks must be born in a dataset in the same TXG after a snapshot of the
dataset is taken.
Those blocks would have the same blk_birth as the dataset's ds_prev_snap_txg
and as such they would be presumed to belong o the snapshot while in fact they
do not.
All the datasets must be clean before sync tasks are run, so the described
scenario may happen only if one of the sync tasks dirties the dataset and
another sync task takes its snapshot.
Then, there will be another sync pass because of the dirty data and the new
blocks will be born in the same TXG when the data is written out.
It seems that almost all of the existing sync tasks modify only MOS and do not
dirty any objsets.
The only exception that I've been able to identify so far is the rollback which
can modify an objset when it zeroes out the objset's ZIL.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Approved by: Gordon Ross <gordon.w.ross@gmail.com>
Author: Andriy Gapon <andriy.gapon@clusterhq.com>
MFC after: 3 weeks
and zfs_ioc_rename
illumos/illumos-gate@690041b9ca690041b9cahttps://www.illumos.org/issues/7180
If a filesystem is not unmounted while the rename is being performed, then, for
example, a concurrect zfs rollback may call zfs_suspend_fs followed by
zfs_resume_fs on the same filesystem.
The latter takes the filesystem's name as an argument. If the filesystem name
changes as a result of the rename, then dmu_objset_hold(osname, zfsvfs, &os)
call in zfs_resume_fs would fail resulting in a kernel panic.
So far I have been able to reproduce this problem on FreeBSD where zfs rename
has -u option that skips the unmounting before doing the renaming.
But I think that in theory the same problem can occur on illumos as well,
because the unmounting is done in userland before invoking the rename ioctl and
there could be a race with, e.g., zfs mount.
panic: solaris assert: dmu_objset_hold(osname, zfsvfs, &zfsvfs->z_os) == 0 (0x2
== 0x0), file: /usr/devel/svn/head/sys/cddl/contrib/opensolaris/uts/common/fs/
zfs/zfs_vfsops.c, line: 2210
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe004df30710
vpanic() at vpanic+0x182/frame 0xfffffe004df30790
panic() at panic+0x43/frame 0xfffffe004df307f0
assfail3() at assfail3+0x2c/frame 0xfffffe004df30810
zfs_resume_fs() at zfs_resume_fs+0xb9/frame 0xfffffe004df30860
zfs_ioc_rollback() at zfs_ioc_rollback+0x61/frame 0xfffffe004df308a0
zfsdev_ioctl() at zfsdev_ioctl+0x65c/frame 0xfffffe004df30940
devfs_ioctl_f() at devfs_ioctl_f+0x156/frame 0xfffffe004df309a0
kern_ioctl() at kern_ioctl+0x246/frame 0xfffffe004df30a00
sys_ioctl() at sys_ioctl+0x171/frame 0xfffffe004df30ae0
amd64_syscall() at amd64_syscall+0x2db/frame 0xfffffe004df30bf0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe004df30bf0
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
MFC after: 2 weeks
It was very wrong to look at the vnode and znode internals without
having locked the vnode first.
Reported by: pho
Tested by: pho
MFC after: 1 week
X-MFC with: r308887
longer used. More precisely, they are always zero because the code that
decremented and incremented them no longer exists.
Bump __FreeBSD_version to mark this change.
Reviewed by: kib, markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8583
The idea was to avoid a false assertion in zfs_lock, but it was
implemented very dangerously and incorrectly.
Reported by: pho
Tested by: pho
MFC after: 1 week
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.
