Commit Graph

1032 Commits

Author SHA1 Message Date
Brian Behlendorf 245b7ab3d1 Hold the zfs_snapentry_t before dispatch
While exceptionally unlikely to cause a problem the zfs_snapentry_t
hold should be taken before the dispatch to prevent any possibility
of the task being processed before the hold.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
2015-12-14 12:06:31 -08:00
Chunwei Chen 1997660170 Fix snapshot automount race cause EREMOTE
When a concorrent mount finishes just before calling to
zfsctl_snapshot_ismounted, if we return EISDIR, the VFS will return
with EREMOTE. We should instead just return 0, so VFS may retry and
would likely notice the dentry is alreadly mounted. This will be
inline with when usermode helper return EBUSY.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-12-14 12:06:31 -08:00
Brian Behlendorf 5ed27c572c Change zfs_snapshot_lock from mutex to rw lock
By changing the zfs_snapshot_lock from a mutex to a rw lock the
zfsctl_lookup_objset() function can be allowed to run concurrently.
This should reduce the latency of fh_to_dentry lookups in ZFS
snapshots which are being accessed over NFS.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
2015-12-14 12:06:31 -08:00
Brian Behlendorf f22f900f15 Fix zfsctl_lookup_objset() deadlock
The zfsctl_snapshot_unmount_delay() function must not be called
from zfsctl_lookup_objset() while it is currently holding the
zfs_snapshot_lock.  This will result in a deadlock.  It is safe
to call zfsctl_snapshot_unmount_delay_impl() directly because the
function already has a reference on the zfs_snapentry_t.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #3997
2015-12-14 12:05:52 -08:00
Brian Behlendorf 5e94284fe5 Set 'zfs_expire_snapshot=0' to disable auto-unmount
There are cases where it's desirable that auto-mounted snapshots
not expire after a fixed duration.  They should be unmounted only
when the filesystem they are a snapshot of is unmounted.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
2015-12-14 11:02:32 -08:00
Chunwei Chen 24ef51f660 Use spa as key besides objsetid for snapentry
objsetid is not unique across pool, so using it solely as key would cause
panic when automounting two snapshot on different pools with the same
objsetid. We fix this by adding spa pointer as additional key.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Issue #3948
Issue #3786
Issue #3887
2015-12-08 16:38:56 -08:00
Brian Behlendorf b58986eebf Use large stacks when available
While stack size will vary by architecture it has historically defaulted to
8K on x86_64 systems.  However, as of Linux 3.15 the default thread stack
size was increased to 16K.  These kernels are now the default in most non-
enterprise distributions which means we no longer need to assume 8K stacks.

This patch takes advantage of that fact by appropriately reverting stack
conservation changes which were made to ensure stability.  Changes which
may have had a negative impact on performance for certain workloads.  This
also has the side effect of bringing the code slightly more in line with
upstream.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #4059
2015-12-07 12:20:43 -08:00
Matthew Ahrens 241b541574 Illumos 5959 - clean up per-dataset feature count code
5959 clean up per-dataset feature count code
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/5959
  https://github.com/illumos/illumos-gate/commit/ca0cc39

Porting notes:

illumos code doesn't check for feature_get_refcount() returning
ENOTSUP (which means feature is disabled) in zdb. zfsonlinux added
a check in https://github.com/zfsonlinux/zfs/commit/784652c
due to #3468. The check was reintroduced here.

Ported-by: Witaut Bajaryn <vitaut.bayaryn@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3965
2015-12-04 14:20:20 -08:00
Brian Behlendorf 072484504f Add zap_prefetch() interface
Provide a generic interface to prefetch ZAP entries by name.  This
functionality is being added for external consumers such as Lustre.
It is based of the existing zap_prefetch_uint64() version which is
used by the deduplication code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #4061
2015-12-04 09:39:20 -08:00
tuxoko b0fe1adeb1 Prevent rm modules.* when make install
This was originally in fe0ed8f910, but somehow
was changed and not working anymore. And it will cause the following error:

modprobe: ERROR: ../libkmod/libkmod.c:506 lookup_builtin_file() could not open builtin file '/lib/modules/4.2.0-18-generic/modules.builtin.bin'

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4027
2015-12-02 14:39:12 -08:00
Chunwei Chen 61d482f7cd Linux 4.4 compat: xattr operations takes xattr_handler
The xattr_hander->{list,get,set} were changed to take a xattr_handler,
and handler_flags argument was removed and should be accessed by
handler->flags.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4021
2015-12-01 16:48:25 -08:00
Chunwei Chen 1a09371678 Linux 4.4 compat: make_request_fn returns blk_qc_t
As part of block polling support in Linux 4.4, make_request_fn should
return a cookie value of type blk_qc_t. For now, we make zvol_request
always return BLK_QC_T_NONE until we assess whether and how we want
to support block polling.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4021
2015-12-01 16:48:08 -08:00
tuxoko 43518d92fd Fix zfs_dirty_data_max overflow on 32-bit
On 32 bit, the calculation of zfs_dirty_data_max from phymem will overflow,
causing it to be smaller than zfs_dirty_data_sync, and will cause txg being
delayed while no one write to disk. The end result is horrendous write speed.

On 4G ram 32-bit VM, before this patch, simple dd results in ~7MB/s. Now it
can reach speed on par with 64-bit VM.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3973
2015-11-19 16:02:47 -08:00
tuxoko d0c614ecf9 Fix null pointer in arc_kmem_reap_now on 32-bit
On 32 bit system, zio_buf_cache is limit to 1M. Larger than that is all NULL.
So we need to avoid reaping them.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3973
2015-11-19 16:01:47 -08:00
Chunwei Chen d287880afd Fix snapshot automount behavior when concurrent or fail
When concurrent threads accessing the snapdir, one will succeed the user
helper mount while others will get EBUSY. However, the original code treats
those EBUSY threads as success and goes on to do zfsctl_snapshot_add, which
causes repeated avl_add and thus panic.

Also, if the snapshot is already mounted somewhere else, a thread accessing
the snapdir will also get EBUSY from user helper mount. And it will cause
strange things as doing follow_down_one will fail and then follow_up will jump
up to the mountpoint of the filesystem and confuse the hell out of VFS.

The patch fix both behavior by returning 0 immediately for the EBUSY threads.
Note, this will have a side effect for the second case where the VFS will
retry several times before returning ELOOP.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4018
2015-11-19 15:36:59 -08:00
Brian Behlendorf 3d8d245fb3 Follow 0/-E convention for module load errors
Because errors during module load are so rare it went unnoticed that
it was possible that a positive errno was returned.  This would result
in the module being loaded, nothing being initialized, and a system
panic shortly thereafter.  This is what was causing the hard failures
in the automated testing.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-11-16 16:10:06 -08:00
AndCycle 256fa983f4 Obey arc_meta_limit default size when changing arc_max
When decreasing the maximum ARC size preserve the 3/4 default
ratio for the arc_meta_limit.  Otherwise, the arc_meta_limit
may be set the same as arc_max.

Signed-off-by: AndCycle <andcycle@andcycle.idv.tw>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4001
2015-11-13 15:45:22 -08:00
Chunwei Chen 07d63f0cb9 Fix fail path in zfs_znode_alloc
When sa_bulk_lookup() fails, unlock_new_inode() will spit out a WARNING. It
will also recursive deadlock on ZFS_OBJ_HOLD_ENTER in zfs_zinactive().

Since we never call insert_inode_locked in fail path, I_NEW is never set, the
inode is never hashed. So unlock_new_inode() can be safely remove it.

We set z_sa_hdl to NULL in fail path so that iput path will stop at
zfs_inactive() without entering zfs_zinactive(). This way we can avoid the
deadlock and prevent double sa_handle_destroy().

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3899
2015-10-13 15:57:17 -07:00
Chunwei Chen aa159afb56 Fix use-after-free in vdev_disk_physio_completion
Currently, vdev_disk_physio_completion will try to wake up an waiter without
first checking the existence. This creates a race window in which complete is
called after dr is freed.

We add dr_wait in dio_request to indicate the existence of waiter. Also,
remove dr_rw since no one is using it, and reorder dr_ref to make the struct
more compact in 64bit.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3917
Issue #3880
2015-10-13 15:25:33 -07:00
Justin T. Gibbs bc4501f75a Illumos 6267 - dn_bonus evicted too early
6267 dn_bonus evicted too early
Reviewed by: Richard Yao <ryao@gentoo.org>
Reviewed by: Xin LI <delphij@freebsd.org>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/6267
  https://github.com/illumos/illumos-gate/commit/d205810

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: Ned Bass bass6@llnl.gov
Issue #3865
Issue #3443
2015-10-13 14:12:02 -07:00
Brian Behlendorf 935434ef01 Fix 'arc_c < arc_c_min' panic
Strictly enforce keeping 'arc_c >= arc_c_min'.  The ASSERTs are
left in place to catch this in a debug build but logic has been
added to gracefully handle in a production build.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3904
2015-10-13 09:23:35 -07:00
Richard Yao 919efe93cb zfs_inode_update should not call dmu_object_size_from_db under spinlock
We should never block when holding a spin lock, but zfs_inode_update can
block in the critical section of a spin lock in zfs_inode_update:

zfs_inode_update -> dmu_object_size_from_db -> zrl_add -> mutex_enter

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3858
2015-09-30 10:47:40 -07:00
Richard Yao bc8ffb2d08 Remove obsolete zv_lock
All users of zv_lock were removed by 37f9dac, but we forgot to remove
it.  Lets remove it as clean up.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3858
2015-09-30 10:43:19 -07:00
Chunwei Chen 45838e3a41 Fix uioskip crash when skip to end
When doing uioskip to skip an iovec to the very end, the current loop
condition will falsely check pass the end of iovec. We fix this checking
uio_iovcnt first.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3806
Closes #3850
2015-09-29 10:06:58 -07:00
Richard Yao b815ec32b3 Userspace can pass zero length segments via writev/readv
Userspace can trigger an assertion by passing a zero-length segment
when assertions are enabled:

[27961.614792] VERIFY3(skip < iov->iov_len) failed (0 < 0)
[27961.614795] PANIC at zfs_uio.c:187:uio_prefaultpages()
[27961.614805] Call Trace:
[27961.614811]   dump_stack+0x45/0x57
[27961.614830]   spl_dumpstack+0x44/0x50 [spl]
[27961.614834]   spl_panic+0xbb/0x100 [spl]
[27961.614908]   uio_prefaultpages+0x134/0x140 [zcommon]
[27961.614930]   zfs_write+0x1fd/0xe80 [zfs]
[27961.615014]   zpl_write_common_iovec+0x7f/0x110 [zfs]
[27961.615035]   zpl_iter_write+0xa0/0xd0 [zfs]
[27961.615037]   do_iter_readv_writev+0x59/0x80
[27961.615063]   do_readv_writev+0x11b/0x260
[27961.615098]   vfs_writev+0x39/0x50
[27961.615100]   SyS_writev+0x4a/0xe0
[27961.615103]   system_call_fastpath+0x16/0x6e

The solution is to delete the assertion. This could potentially
occur in uiomove as well, which contains analogous assertions
that appear similarly unnecessary, so we remove those as well.

Reported-by: Jonathan Vasquez <jvasquez1011@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Issue #3792
2015-09-25 12:51:16 -07:00
Brian Behlendorf a3000f9358 Revert "dmu_objset_userquota_get_ids uses dn_bonus unsafely"
This reverts commit 5f8e1e8505.  It
was determined that this patch introduced the quota regression
described in #3789.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3443
Issue #3789
2015-09-25 12:50:24 -07:00
Brian Behlendorf 5592404784 Fix synchronous behavior in __vdev_disk_physio()
Commit b39c22b set the READ_SYNC and WRITE_SYNC flags for a bio
based on the ZIO_PRIORITY_* flag passed in.  This had the unnoticed
side-effect of making the vdev_disk_io_start() synchronous for
certain I/Os.

This in turn resulted in vdev_disk_io_start() being able to
re-dispatch zio's which would result in a RCU stalls when a disk
was removed from the system.  Additionally, this could negatively
impact performance and explains the performance regressions reported
in both #3829 and #3780.

This patch resolves the issue by making the blocking behavior
dependent on a 'wait' flag being passed rather than overloading
the passed bio flags.

Finally, the WRITE_SYNC and READ_SYNC behavior is restricted to
non-rotational devices where there is no benefit to queuing to
aggregate the I/O.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3652
Issue #3780
Issue #3785
Issue #3817
Issue #3821
Issue #3829
Issue #3832
Issue #3870
2015-09-25 12:47:31 -07:00
Brian Behlendorf ef5b2e1048 Avoid blocking in arc_reclaim_thread()
As described in the comment above arc_reclaim_thread() it's critical
that the reclaim thread be careful about blocking.  Just like it must
never wait on a hash lock, it must never wait on a task which can in
turn wait on the CV in arc_get_data_buf().  This will deadlock, see
issue #3822 for full backtraces showing the problem.

To resolve this issue arc_kmem_reap_now() has been updated to use the
asynchronous arc prune function.  This means that arc_prune_async()
may now be called while there are still outstanding arc_prune_tasks.
However, this isn't a problem because arc_prune_async() already
keeps a reference count preventing multiple outstanding tasks per
registered consumer.  Functionally, this behavior is the same as
the counterpart illumos function dnlc_reduce_cache().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #3808
Issue #3834
Issue #3822
2015-09-25 12:45:47 -07:00
Brian Behlendorf 04870568e6 Disable zpl_nr_cached_objects() callback
The zpl_nr_cached_objects() function has been disabled because in the
current code it doesn't provide any critical functionality and it may
result in a deadlock under certain circumstances.  However, because
we expect to need these hooks in the future this code has not been
entirely removed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3719
2015-09-25 12:45:42 -07:00
Brian Behlendorf d4787d55ad Allow NFS activity to defer snapshot unmounts
Accessing a snapshot via NFS should cause an auto-unmount of that
snapshot to be deferred until such as time as the snapshot is idle.
This is analogous to the zpl_revalidate logic employed by locally
mounted snapshots.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3794
2015-09-25 12:45:38 -07:00
Lukas Wunner 784a7fe5d9 Linux 4.3 compat: bio_end_io_t / BIO_UPTODATE
Commit torvalds/linux@4246a0b63b
("block: add a bi_error field to struct bio") dropped the error
argument from bio_endio in favor of newly introduced bio->bi_error.
This also replaces bio->bi_flags value BIO_UPTODATE.

bio_endio was a 3 argument function until Linux 2.6.24, which made it
a 2 argument function, and now the prototype has changed yet again to
a 1 argument function. Support for pre 2.6.24 kernels was already
dropped with 37f9dac592 ("zvol processing should use struct bio")
which assumed the 2 argument version in zvol_request(). Remaining code
to support the 3 argument version is hereby removed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Issue #3799
2015-09-25 12:44:54 -07:00
Don Brady 56b3986316 Add large block support to zpios(1) benchmark
As part of the large block support effort, it makes sense to add
support for large blocks to **zpios(1)**. The specifying of a zfs
block size for zpios is optional and will default to 128K if the
block size is not specified.

  `zpios ... -S size | --blocksize size ...`

This will use *size* ZFS blocks for each test, specified as a comma
delimited list with an optional unit suffix. The supported range is
powers of two from 128K through 16M. A range of block sizes can be
tested as follows: `-S 128K,256K,512K,1M`

Example run below
(non realistic results from a VM and output abbreviated for space)

```
 --regioncount=750 --regionsize=8M --chunksize=1M --offset=4K
 --threaddelay=0 --cleanup --human-readable --verbose --cleanup
 --blocksize=128K,256K,512K,1M

 th-cnt  rg-cnt  rg-sz  ch-sz  blksz  wr-data wr-bw   rd-data rd-bw
---------------------------------------------------------------------
 4       750     8m     1m     128k   5g      90.06m  5g      93.37m
 4       750     8m     1m     256k   5g      79.71m  5g      99.81m
 4       750     8m     1m     512k   5g      42.20m  5g      93.14m
 4       750     8m     1m     1m     5g      35.51m  5g      89.36m
 8       750     8m     1m     128k   5g      85.49m  5g      90.81m
 8       750     8m     1m     256k   5g      61.42m  5g      99.24m
 8       750     8m     1m     512k   5g      49.09m  5g     108.78m
 16      750     8m     1m     128k   5g      86.28m  5g      88.73m
 16      750     8m     1m     256k   5g      64.34m  5g      93.47m
 16      750     8m     1m     512k   5g      68.84m  5g     124.47m
 16      750     8m     1m     1m     5g      53.97m  5g      97.20m
---------------------------------------------------------------------
```

Signed-off-by: Don Brady <don.brady@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3795
Closes #2071
2015-09-22 09:13:20 -07:00
Ned Bass 3af56fd95f Honor xattr=sa dataset property
ZFS incorrectly uses directory-based extended attributes even when
xattr=sa is specified as a dataset property or mount option. Support to
honor temporary mount options including "xattr" was added in commit
0282c4137e. There are two issues with the
mount option handling:

* Libzfs has historically included "xattr" in its list of default mount
  options. This overrides the dataset property, so the dataset is always
  configured to use directory-based xattrs even when the xattr dataset
  property is set to off or sa. Address this by removing "xattr" from
  the set of default mount options in libzfs.

* There was no way to enable system attribute-based extended attributes
  using temporary mount options. Add the mount options "saxattr" and
  "dirxattr" which enable the xattr behavior their names suggest.  This
  approach has the advantages of mirroring the valid xattr dataset
  property values and following existing conventions for mount option
  names.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3787
2015-09-19 14:04:14 -07:00
Brian Behlendorf 66aad10ce8 Fix NULL as mount(2) syscall data parameter
Passing NULL for the mount data should not result in EINVAL.  It
should be treated as if an empty string were passed and succeed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #3771
2015-09-19 14:03:01 -07:00
Richard Yao f52ebcb3eb Discard on zvols should not exceed the length of a block
37f9dac592 replaced the end-start
calculation with a cached value, but neglected to update it on discard
operations. This can cause us to discard data not requested, causing
data loss on zvols.

Reported-by: Richard Connon <richard.connon@zynstra.com>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3798
2015-09-19 14:00:14 -07:00
Arne Jansen 4e0f33ffe0 Illumos 6214 - zpools going south
6214 zpools going south
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>

References:
  https://www.illumos.org/issues/6214
  http://cr.illumos.org/~webrev/sensille/6214_zpools_going_south/

Porting Notes:

Reintroduce b_compress to the l2arc_buf_hdr_t.  In commit b9541d6
the compression flags were moved to the generic b_flags in the
arc_buf_hdr_t.  This is a problem because l2arc_compress_buf()
may manipulate the compression flags and this can only be done
safely under the hash lock which is not held.  See Illumos 6214
for a detailed analysis of the race.

HDR_GET_COMPRESS() macro was removed from arc_buf_info().

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3757
2015-09-11 11:14:38 -07:00
Brian Behlendorf 9965059ab9 Prefetch start and end of volumes
When adding a zvol to the system prefetch zvol_prefetch_bytes from the
start and end of the volume.  Prefetching these regions of the volume is
desirable because they are likely to be accessed immediately by blkid(8),
the kernel scanning for a partition table, or another task which probes
the devices.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3659
2015-09-09 14:38:29 -07:00
Richard Yao 8198d18ca7 Reintroduce IO accounting on zvols on Linux 3.19+
zfsonlinux/zfs@e20cd6f7a8 caused us to
lose IO accounting on zvols. When I originally wrote that last year, the
symbols we needed to maintain IO accounting were GPL exported, but
torvalds/linux@394ffa503b provided
suitable symbols for restoring this functionality 4 months later.  We
can call them to restore the IO accounting on Linux 3.19 and later as
well as any older kernels where that patch is backported.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3741
2015-09-09 09:29:24 -07:00
Brian Behlendorf 3b36f8319d Add dbgmsg kstat
Internally ZFS keeps a small log to facilitate debugging.  By default
the log is disabled, to enable it set zfs_dbgmsg_enable=1.  The contents
of the log can be accessed by reading the /proc/spl/kstat/zfs/dbgmsg file.
Writing 0 to this proc file clears the log.

$ echo 1 >/sys/module/zfs/parameters/zfs_dbgmsg_enable
$ echo 0 >/proc/spl/kstat/zfs/dbgmsg
$ zpool import tank
$ cat /proc/spl/kstat/zfs/dbgmsg
1 0 0x01 -1 0 2492357525542 2525836565501
timestamp    message
1441141408   spa=tank async request task=1
1441141408   txg 70 open pool version 5000; software version 5000/5; ...
1441141409   spa=tank async request task=32
1441141409   txg 72 import pool version 5000; software version 5000/5; ...
1441141414   command: lt-zpool import tank

Note the zfs_dbgmsg() and dprintf() functions are both now mapped to
the same log.  As mentioned above the kernel debug log can be accessed
though the /proc/spl/kstat/zfs/dbgmsg kstat.  For user space consumers
log messages are immediately written to stdout after applying the
ZFS_DEBUG environment variable.

$ ZFS_DEBUG=on ./cmd/ztest/ztest -V

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #3728
2015-09-04 16:08:14 -07:00
Brian Behlendorf 0500e835af Support accessing .zfs/snapshot via NFS
This patch is based on the previous work done by @andrey-ve and
@yshui.  It triggers the automount by using kern_path() to traverse
to the known snapshout mount point.  Once the snapshot is mounted
NFS can access the contents of the snapshot.

Allowing NFS clients to access to the .zfs/snapshot directory would
normally mean that a root user on a client mounting an export with
'no_root_squash' would be able to use mkdir/rmdir/mv to manipulate
snapshots on the server.  To prevent configuration mistakes a
zfs_admin_snapshot module option was added which disables the
mkdir/rmdir/mv functionally.  System administators desiring this
functionally must explicitly enable it.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2797
Closes #1655
Closes #616
2015-09-04 13:23:53 -07:00
Andrey Vesnovaty aa9b27080b Fix invalid fileid for snapshot root dentry
Prevents NFS client from detection of different fileids of snapshot root dentry
before & after snapshot mount.

Signed-off-by: Andrey Vesnovaty <andrey.vesnovaty@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-09-04 13:23:06 -07:00
Brian Behlendorf e20cd6f7a8 Merge branch 'zvol'
Performance improvements for zvols.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3720
2015-09-04 13:14:21 -07:00
Richard Yao fa56567630 Support secure discard on zvols
Linux 2.6.36 introduced REQ_SECURE to indicate when discards *must* be
processed, such that we cannot do optimizations like block alignment.
Consequently, the discard semantics prior to 2.6.36 require us to always
process unaligned discards. Previously, we would do this optimization
regardless. This patch changes things to correctly restrict this
optimization to situations where REQ_SECURE exists, but is not included
in the flags.

Signed-off-by: Richard Yao <ryao@gentoo.org>
2015-09-04 15:37:24 -04:00
Richard Yao 37f9dac592 zvol processing should use struct bio
Internally, zvols are files exposed through the block device API. This
is intended to reduce overhead when things require block devices.
However, the ZoL zvol code emulates a traditional block device in that
it has a top half and a bottom half. This is an unnecessary source of
overhead that does not exist on any other OpenZFS platform does this.
This patch removes it. Early users of this patch reported double digit
performance gains in IOPS on zvols in the range of 50% to 80%.

Comments in the code suggest that the current implementation was done to
obtain IO merging from Linux's IO elevator. However, the DMU already
does write merging while arc_read() should implicitly merge read IOs
because only 1 thread is permitted to fetch the buffer into ARC. In
addition, commercial ZFSOnLinux distributions report that regular files
are more performant than zvols under the current implementation, and the
main consumers of zvols are VMs and iSCSI targets, which have their own
elevators to merge IOs.

Some minor refactoring allows us to register zfs_request() as our
->make_request() handler in place of the generic_make_request()
function. This eliminates the layer of code that broke IO requests on
zvols into a top half and a bottom half. This has several benefits:

1. No per zvol spinlocks.
2. No redundant IO elevator processing.
3. Interrupts are disabled only when actually necessary.
4. No redispatching of IOs when all taskq threads are busy.
5. Linux's page out routines will properly block.
6. Many autotools checks become obsolete.

An unfortunate consequence of eliminating the layer that
generic_make_request() is that we no longer calls the instrumentation
hooks for block IO accounting. Those hooks are GPL-exported, so we
cannot call them ourselves and consequently, we lose the ability to do
IO monitoring via iostat.  Since zvols are internally files mapped as
block devices, this should be okay. Anyone who is willing to accept the
performance penalty for the block IO layer's accounting could use the
loop device in between the zvol and its consumer. Alternatively, perf
and ftrace likely could be used. Also, tools like latencytop will still
work. Tools such as latencytop sometimes provide a better view of
performance bottlenecks than the traditional block IO accounting tools
do.

Lastly, if direct reclaim occurs during spacemap loading and swap is on
a zvol, this code will deadlock. That deadlock could already occur with
sync=always on zvols. Given that swap on zvols is not yet production
ready, this is not a blocker.

Signed-off-by: Richard Yao <ryao@gentoo.org>
2015-09-04 15:30:24 -04:00
Tim Chase dca8c34da4 Prevent reclaim in the traverse prefetch thread
Reclaim in the traverse prefetch thread, which is run on the system
taskq, can overrun the stack.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #3733
2015-09-04 08:43:28 -07:00
Brian Behlendorf 0282c4137e Add temporary mount options
Add the required kernel side infrastructure to parse arbitrary
mount options.  This enables us to support temporary mount
options in largely the same way it is handled on other platforms.

See the 'Temporary Mount Point Properties' section of zfs(8)
for complete details.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #985
Closes #3351
2015-09-03 14:14:55 -07:00
Tim Chase 69de34219a Dbuf hash table should be sized as is the arc hash table
Commit 49ddb31506 added the
zfs_arc_average_blocksize parameter to allow control over the size of
the arc hash table.  The dbuf hash table's size should be determined
similarly.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3721
2015-09-02 09:33:02 -07:00
Brian Behlendorf 6cde64351e Add spa_slop_shift module option
Allow for easy turning of a pools reserved free space.  Previous
versions of ZFS (v0.6.4 and earlier) held 1/64 of the pools capacity
in reserve.  Commits 3d45fdd and 0c60cc3 increased this to 1/32.
Setting spa_slop_shift=6 will restore the previous default setting.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3724
2015-09-02 09:30:18 -07:00
Richard Yao fb40095f5f Disable LBA weighting on files and SSDs
The LBA weighting makes sense on rotational media where the outer tracks
have twice the bandwidth of the inner tracks. However, it is detrimental
on nonrotational media such as solid state disks, where the only effect
is to ensure that metaslabs enter the best-fit allocation behavior
sooner, which is detrimental to performance. It also makes no sense on
files where the underlying filesystem can arrange things however it
wants.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3712
2015-09-01 15:22:07 -07:00
tuxoko cafbd2aca3 Check for RW_WRITE_HELD in zfs_inactive
Before read locking z_teardown_inactive_lock, we need to check if we have
already had write lock on it. Otherwise, we would deadlock on ourself when
doing rollback:

zfs_ioc_rollback
->zfs_suspend_fs (z_teardown_inactive_lock, RW_WRITER)
->zfs_resume_fs->zfs_rezget->zfs_iput_async->iput-> ...
  ->zfs_inactive (z_teardown_inactive_lock, RW_READER)

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2869
2015-09-01 10:17:57 -07:00