The fast write mutex is intended to protect accounting, but it is
redundant because all accounting is performed through atomic operations.
It also serializes all metaslab IO behind a mutex, which introduces a
theoretical scaling regression that the Illumos developers did not like
when we showed this to them. Removing it makes the selection of the
metaslab_group lock free as it is on Illumos. The selection is not quite
the same without the lock because the loop races with IO completions,
but any imbalances caused by this are likely to be corrected by
subsequent metaslab group selections.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3643
The zfs_znode_hold_enter() / zfs_znode_hold_exit() functions are used to
serialize access to a znode and its SA buffer while the object is being
created or destroyed. This kind of locking would normally reside in the
znode itself but in this case that's impossible because the znode and SA
buffer may not yet exist. Therefore the locking is handled externally
with an array of mutexs and AVLs trees which contain per-object locks.
In zfs_znode_hold_enter() a per-object lock is created as needed, inserted
in to the correct AVL tree and finally the per-object lock is held. In
zfs_znode_hold_exit() the process is reversed. The per-object lock is
released, removed from the AVL tree and destroyed if there are no waiters.
This scheme has two important properties:
1) No memory allocations are performed while holding one of the z_hold_locks.
This ensures evict(), which can be called from direct memory reclaim, will
never block waiting on a z_hold_locks which just happens to have hashed
to the same index.
2) All locks used to serialize access to an object are per-object and never
shared. This minimizes lock contention without creating a large number
of dedicated locks.
On the downside it does require znode_lock_t structures to be frequently
allocated and freed. However, because these are backed by a kmem cache
and very short lived this cost is minimal.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4106
Add a zfs_object_mutex_size module option to facilitate resizing the
the per-dataset znode mutex array. Increasing this value may help
make the deadlock described in #4106 less common, but this is not a
proper fix. This patch is primarily to aid debugging and analysis.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #4106
3465 ::walk ... | ::<dcmd> misinterprets input as symbol names
3466 ::tsd should handle missing/NULL values better
3467 mdb_ctf_vread() could be more useful
3468 mdb enhancements for zfs development
3470 ::whatis does not print callers from KMF_LITE
3473 mdb_get_module() returns wrong module
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Dan McDonald <danmcd@nexenta.com>
References:
https://www.illumos.org/issues/3468https://github.com/illumos/illumos-gate/commit/28e4da2
Porting notes:
- The only portion of this patch which applies to ZoL is a small
change to types used in the refcount structure.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4216
Under RHEL6/CentOS6 the default stack size must be increased to 32K
to prevent overflowing the stack when running ztest. This isn't an
issue for other distributions due to either the version of pthreads
or perhaps the compiler. Doubling the stack size resolves the
issue safely for all distribution and leaves us some headroom.
$ sudo -E ztest -V -T 300 -f /var/tmp/
5 vdevs, 7 datasets, 23 threads, 300 seconds...
loading space map for vdev 0 of 1, metaslab 0 of 30 ...
...
loading space map for vdev 0 of 1, metaslab 14 of 30 ...
child died with signal 11
Exited ztest with error 3
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4215
3749 zfs event processing should work on R/O root filesystems
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/3749https://github.com/illumos/illumos-gate/commit/3cb69f7
Porting notes:
- [include/sys/spa_impl.h]
- ffe9d38 Add generic errata infrastructure
- 1421c89 Add visibility in to arc_read
- [include/sys/fm/fs/zfs.h]
- 2668527 Add linux events
- 6283f55 Support custom build directories and move includes
- [module/zfs/spa_config.c]
- Updated spa_config_sync() to match illumos with the exception
of a Linux specific block.
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
6171 dsl_prop_unregister() slows down dataset eviction.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/6171https://github.com/illumos/illumos-gate/commit/03bad06
Porting notes:
- Conflicts
- 3558fd7 Prototype/structure update for Linux
- 2cf7f52 Linux compat 2.6.39: mount_nodev()
- 13fe019 Illumos #3464
- 241b541 Illumos 5959 - clean up per-dataset feature count code
- dsl_prop_unregister() preserved until out of tree consumers
like Lustre can transition to dsl_prop_unregister_all().
- Fixing 'space or tab at end of line' in include/sys/dsl_dataset.h
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
4929 want prevsnap property
Reviewed by: Adam Leventhal <adam.leventhal@delphix.com>
Reviewed by: Matt Amdur <matt.amdur@delphix.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Boris Protopopov <bprotopopov@hotmail.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/4929https://github.com/illumos/illumos-gate/commit/b461c74
Porting notes:
- [include/sys/fs/zfs.h]
- f67d70 Create an 'overlay' property
- 11b9ec Add full SELinux support
- [fs/zfs/dsl_dataset.c]
- This increases the stack size of dsl_dataset_stats() but
nothing has been changed until this is shown to be an issue.
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
4891 want zdb option to dump all metadata
Reviewed by: Sonu Pillai <sonu.pillai@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Garrett D'Amore <garrett@damore.org>
We'd like a way for zdb to dump metadata in a machine-readable
format, so that we can bring that back from a customer site for
in-house diagnosis. Think of it as a crash dump for zpools,
which can be used for post-mortem analysis of a malfunctioning
pool
References:
https://www.illumos.org/issues/4891https://github.com/illumos/illumos-gate/commit/df15e41
Porting notes:
- [cmd/zdb/zdb.c]
- a5778ea zdb: Introduce -V for verbatim import
- In main() getopt 'opt' variable removed and the code was
brought back in line with illumos.
- [lib/libzpool/kernel.c]
- 1e33ac1 Fix Solaris thread dependency by using pthreads
- f0e324f Update utsname support
- 4d58b69 Fix vn_open/vn_rdwr error handling
- In vn_open() allocate 'dumppath' on heap instead of stack
- Properly handle 'dump_fd == -1' error path
- Free 'realpath' after added vn_dumpdir_code block
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
3749 zfs event processing should work on R/O root filesystems
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/3749https://github.com/illumos/illumos-gate/commit/3cb69f7
Porting notes:
- [include/sys/spa_impl.h]
- ffe9d38 Add generic errata infrastructure
- 1421c89 Add visibility in to arc_read
- [include/sys/fm/fs/zfs.h]
- 2668527 Add linux events
- 6283f55 Support custom build directories and move includes
- [module/zfs/spa_config.c]
- Updated spa_config_sync() to match illumos with the exception
of a Linux specific block.
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The function sa_update() accepts a 32-bit length parameter and
assigns it to a 16-bit field in sa_bulk_attr_t, potentially
truncating the passed-in value. This could lead to corrupt system
attribute (SA) records getting written to the pool. Add a VERIFY to
sa_update() to detect cases where overflow would occur. The SA length
is limited to 16-bit values by the on-disk format defined by
sa_hdr_phys_t.
The function zfs_sa_set_xattr() is vulnerable to this bug if the
unpacked nvlist of xattrs is less than 64k in size but the packed
size is greater than 64k. Fix this by appropriately checking the
size of the packed nvlist before calling sa_update(). Add error
handling to zpl_xattr_set_sa() to keep the cached list of SA-based
xattrs consistent with the data on disk.
Lastly, zfs_sa_set_xattr() calls dmu_tx_abort() on an assigned
transaction if sa_update() returns an error, but the DMU only allows
unassigned transactions to be aborted. Wrap the sa_update() call in a
VERIFY0, remove the transaction abort, and call dmu_tx_commit()
unconditionally. This is consistent practice with other callers
of sa_update().
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes#4150
5745 zfs set allows only one dataset property to be set at a time
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Reviewed by: Richard PALO <richard@NetBSD.org>
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Approved by: Rich Lowe <richlowe@richlowe.net>
References:
https://www.illumos.org/issues/5745https://github.com/illumos/illumos-gate/commit/3092556
Porting notes:
- Fix the missing braces around initializer, zfs_cmd_t zc = {"\0"};
- Remove extra format argument in zfs_do_set()
- Declare at the top:
- zfs_prop_t prop;
- nvpair_t *elem;
- nvpair_t *next;
- int i;
- Additionally initialize:
- int added_resv = 0;
- zfs_prop_t prop = 0;
- Assign 0 install of NULL for uint64_t types.
- zc->zc_nvlist_conf = '\0';
- zc->zc_nvlist_src = '\0';
- zc->zc_nvlist_dst = '\0';
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3574
Both lock types were introduced in SPL to allow some locks to be
taken/released with linux lockdep turned off. See SPL commit for
details.
Add the new lock types to zfs_context.h to allow user space compilation.
Depends on SPL commit 692ae8d
SPL pull request refs/pull/480/head
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3895
This deadlock may manifest itself in slightly different ways but
at the core it is caused by a memory allocation blocking on file-
system reclaim in the zio pipeline. This is normally impossible
because zio_execute() disables filesystem reclaim by setting
PF_FSTRANS on the thread. However, kmem cache allocations may
still indirectly block on file system reclaim while holding the
critical vq->vq_lock as shown below.
To resolve this issue zio_buf_alloc_flags() is introduced which
allocation flags to be passed. This can then be used in
vdev_queue_aggregate() with KM_NOSLEEP when allocating the
aggregate IO buffer. Since aggregating the IO is purely a
performance optimization we want this to either succeed or fail
quickly. Trying too hard to allocate this memory under the
vq->vq_lock can negatively impact performance and result in
this deadlock.
* z_wr_iss
zio_vdev_io_start
vdev_queue_io -> Takes vq->vq_lock
vdev_queue_io_to_issue
vdev_queue_aggregate
zio_buf_alloc -> Waiting on spl_kmem_cache process
* z_wr_int
zio_vdev_io_done
vdev_queue_io_done
mutex_lock -> Waiting on vq->vq_lock held by z_wr_iss
* txg_sync
spa_sync
dsl_pool_sync
zio_wait -> Waiting on zio being handled by z_wr_int
* spl_kmem_cache
spl_cache_grow_work
kv_alloc
spl_vmalloc
...
evict
zpl_evict_inode
zfs_inactive
dmu_tx_wait
txg_wait_open -> Waiting on txg_sync
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#3808Closes#3867
Since uio now supports bvec, we can convert bio into uio and reuse
dmu_{read,write}_uio. This way, we can remove some duplicate code.
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4078
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
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/5959https://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
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
Adding additional entries to the efi conversion array will help prevent
the overwriting of the GPTs of disks with in-use file systems in more
cases. Most notably, this adds partition type 8300 "Linux filesystem"
(0FC63DAF-8483-4772-8E79-3D69D8477DE4), which is often used for ext4 and
btrfs, among others.
This commit itself does nothing to address the underlying problematic
behavior that check_slice() isn't called on partitions of an
unrecognized type, even when they contain a currently mounted file
system.
The additional entries were derived from these two resources:
https://en.wikipedia.org/wiki/GUID_Partition_Tablehttp://sourceforge.net/p/gptfdisk/code/ci/master/tree/parttypes.cc
Signed-off-by: ilovezfs <ilovezfs@icloud.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4016
Currently, the SET_ERROR tracepoint triggers regardless of whether there
is an error or not. On Illumos, SET_ERROR only triggers on an actual
error, which is avoids irrelevant noise. Linux 2.6.38 added support for
conditional tracepoints, so we modify SET_ERROR to use them when they
are avaliable for functionality equivalent to the Illumos functionality.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4043
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
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
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#3795Closes#2071
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
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/6214http://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
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
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
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>
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#985Closes#3351
Pre-2.6.37 kernels support REQ_FUA in request flags, but not in BIO
flags. zvols are the only consumer of VDEV_REQ_FUA and since they are
passed requests, they should be obey the REQ_FUA flag like later
kernels. This optimization will only matter on 2.6.36 and 2.6.37 because
the zvol rework changes things to use bio, where we no longer are able
to distinguish on earlier kernels
Signed-off-by: Richard Yao <ryao@gentoo.org>
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
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
This is needed for supporting kernels earlier than 2.6.30. Support for
those kernels was dropped, so we can safely remove this check.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This is needed for supporting kernels earlier than 2.6.30. Support for
those kernels was dropped, so we can safely remove this check.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
