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>
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
Adds zio_taskq_batch_pct as an exported module parameter,
allowing users to modify it at module load time.
Signed-off-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4110
Correct some misspelled words and grammatical errors, and remove
trailing white space in the man pages.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4115
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
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
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
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#2797Closes#1655Closes#616
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
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
Add new keyword 'slot' to vdev_id.conf
This selects from where to get the slot number for a SAS/SATA disk
Needed to enable access to the physical position of a disk in a
Supermicro 2027R-AR24NV .
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#3693
This brings the behavior of arc_memory_throttle() back in sync with
illumos. The updated memory throttling policy roughly goes like this:
* Never throttle if more than 10% of memory is free. This threshold
is configurable with the zfs_arc_lotsfree_percent module option.
* Minimize any throttling of kswapd even when free memory is below
the set threshold. Allow it to write out pages as quickly as
possible to help alleviate the memory pressure.
* Delay all other threads when free memory is below the set threshold
in order to avoid compounding the memory pressure. Buffers will be
evicted from the ARC to reduce the issue.
The Linux specific zfs_arc_memory_throttle_disable module option has
been removed in favor of the existing zfs_arc_lotsfree_percent tuning.
Setting zfs_arc_lotsfree_percent=0 will have the same effect as
zfs_arc_memory_throttle_disable and it was therefore redundant.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3637
While Linux doesn't provide detailed information about the state of
the VM it does provide us total free pages. This information should
be incorporated in to the arc_available_memory() calculation rather
than solely relying on a signal from direct reclaim. Conceptually
this brings arc_available_memory() back in sync with illumos.
It is also desirable that the target amount of free memory be tunable
on a system. While the default values are expected to work well
for most workloads there may be cases where custom values are needed.
The zfs_arc_sys_free module option was added for this purpose.
zfs_arc_sys_free - The target number of bytes the ARC should leave
as free memory on the system. This value can
checked in /proc/spl/kstat/zfs/arcstats and
setting this module option will override the
default value.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3637
The zvol_threads module option should be bounded to a reasonable
range. The taskq must have at least 1 thread and shouldn't have
more than 1,024 at most. The default value of 32 is a reasonable
default.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3614
Commit f521ce1 removed the minimum value for "arc_p" allowing it to
drop to zero or grow to "arc_c". This was done to improve specific
workload which constantly dirties new "metadata" but also frequently
touches a "small" amount of mfu data (e.g. mkdir's).
This change may still be desirable but it needs to be re-investigated.
in the context of the recent ARC changes from upstream. Therefore
this code is being restored to facilitate benchmarking. By setting
"zfs_arc_p_min_shift=64" we easily compare the performance.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3533
5661 ZFS: "compression = on" should use lz4 if feature is enabled
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Reviewed by: Xin LI <delphij@freebsd.org>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://github.com/illumos/illumos-gate/commit/db1741fhttps://www.illumos.org/issues/5661
Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3571
A few minor mistakes than should be fixed:
zpool:
compatability -> compatibility
zfs:
accessable -> accessible
availible -> available
zfs-events:
availible -> available
zfs-module-parameters:
proceding -> proceeding
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3544
This seems generally useful. metaslab_aliquot is the ZFS allocation
granularity, which is roughly equivalent to what is called the stripe
size in traditional RAID arrays. It seems relevant to performance
tuning.
Signed-off-by: Etienne Dechamps <etienne@edechamps.fr>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
sysstat's iostat omits the first report when the -y option is used.
This patch adds that functionality and omits the first report with
statistics since system boot.
Signed-off-by: Hajo Möller <dasjoe@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3439
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Porting notes and other significant code changes:
The illumos 5368 patch (ARC should cache more metadata), which
was never picked up by ZoL, is mostly reverted by this patch.
Since ZoL relies on the kernel asynchronously calling the shrinker to
actually reap memory, the shrinker wakes up arc_reclaim_waiters_cv every
time it runs.
The arc_adapt_thread() function no longer calls arc_do_user_evicts()
since the newly-added arc_user_evicts_thread() calls it periodically.
Notable conflicting ZoL commits which conflicted with this patch or
whose effects are either duplicated or un-done by this patch:
302f753 - Integrate ARC more tightly with Linux
39e055c - Adjust arc_p based on "bytes" in arc_shrink
f521ce1 - Allow "arc_p" to drop to zero or grow to "arc_c"
77765b5 - Remove "arc_meta_used" from arc_adjust calculation
94520ca - Prune metadata from ghost lists in arc_adjust_meta
Trace support for multilist_insert() and multilist_remove() has been
added and produces the following output:
fio-12498 [077] .... 112936.448324: zfs_multilist__insert: ml { offset 240 numsublists 80 sublistidx 63 }
fio-12498 [077] .... 112936.448347: zfs_multilist__remove: ml { offset 240 numsublists 80 sublistidx 29 }
The following arcstats have been removed:
recycle_miss - Used by arcstat.py and arc_summary.py, both of which
have been updated appropriately.
l2_writes_hdr_miss
The following arcstats have been added:
evict_not_enough - Number of times arc_evict_state() was unable to
evict enough buffers to reach its target amount.
evict_l2_skip - Number of times arc_evict_hdr() skipped eviction
because it was being written to the l2arc.
l2_writes_lock_retry - Replaces l2_writes_hdr_miss. Number of times
l2arc_write_done() failed to acquire hash_lock (and re-tries).
arc_meta_min - Shows the value of the zfs_arc_meta_min module
parameter (see below).
The "index" column of the "dbuf" kstat has been removed since it doesn't
have a direct analog in the new multilist scheme. Additional multilist-
related stats could be added in the future but would likely require
extensions to the mulilist API.
The following module parameters have been added:
zfs_arc_evict_batch_limit - Number of ARC headers to free per sub-list
before moving on to the next sub-list.
zfs_arc_meta_min - Enforce a floor on the amount of metadata in
the ARC.
zfs_arc_num_sublists_per_state - Number of multilist sub-lists per
ARC state.
zfs_arc_overflow_shift - Controls amount by which the ARC must exceed
the target size to be considered "overflowing".
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov
* Add information about the 'zpool events' command in zpool(8).
* More events and payloads defined in zfs-events(5).
* I/O Stages and I/O Flags sections added.
* Remove unused legacy "zio_deadline" payload define.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3467
If the pool/dataset command-line argument is specified with a trailing
slash, for example, "tank/", it is interpreted as the root dataset.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3415
This commit updates the copyright boilerplate within the ZED subtree.
The instructions for appending a contributor copyright line have
been removed. Manually maintaining copyright notices in this
manner is error-prone, imprecise at a file-scope granularity, and
oftentimes inaccurate. These lines can become a pernicious source of
merge conflicts. A commit log is better suited to maintaining this
information. Consequently, a line has been added to the boilerplate
to refer to the git commit log for authoritative copyright attribution.
To account for the scenario where a file may become separated from
the codebase and commit history (i.e., it is copied somewhere else),
a line has been added to identify the file's origin.
http://softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html
Signed-off-by: Chris Dunlap <cdunlap@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3384
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/5027https://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
Support exporting all imported pools in one go, using 'zpool export -a'.
This is accomplished by moving the export parts from zpool_do_export()
in to the new function zpool_export_one(). The for_each_pool() function
is used to enumerate the list of pools to be exported. Passing an argc
of 0 implies the function should be called on all pools.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: #3203
3897 zfs filesystem and snapshot limits
Author: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>
References:
https://www.illumos.org/issues/3897https://github.com/illumos/illumos-gate/commit/a2afb61
Porting Notes:
dsl_dataset_snapshot_check(): reduce stack usage using kmem_alloc().
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The default was changed in #2820.
Signed-off-by: cburroughs <chris.burroughs@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3341
Commit b1a3e93217 accidentally
introduced an intentation error between the 'zfs receive'
and 'zfs allow' detailed documentation sections.
Signed-off-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3312
Commit b738bc5 should have updated the default value of zfs_pd_bytes_max
in the zfs(8) man page. The correct default value is 50*1024*1024.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5694 traverse_prefetcher does not prefetch enough
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
https://www.illumos.org/issues/5694https://github.com/illumos/illumos-gate/commit/34d7ce05
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3230
The zio_inject.c keeps zio_injection_enabled as a counter of
fault handlers, so it should not be exported to user space as
a module option.
Several EXPORT_SYMBOLs are moved from zio.c to zio_inject.c,
where the symbols are defined.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3199
The goal of this function is to evict enough meta data buffers from the
ARC in order to enforce the arc_meta_limit. Achieving this is slightly
more complicated than it appears because it is common for data buffers
to have holds on meta data buffers. In addition, dnode meta data buffers
will be held by the dnodes in the block preventing them from being freed.
This means we can't simply traverse the ARC and expect to always find
enough unheld meta data buffer to release.
Therefore, this function has been updated to make alternating passes
over the ARC releasing data buffers and then newly unheld meta data
buffers. This ensures forward progress is maintained and arc_meta_used
will decrease. Normally this is sufficient, but if required the ARC
will call the registered prune callbacks causing dentry and inodes to
be dropped from the VFS cache. This will make dnode meta data buffers
available for reclaim. The number of total restarts in limited by
zfs_arc_meta_adjust_restarts to prevent spinning in the rare case
where all meta data is pinned.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Issue #3160
Originally when the ARC prune callback was introduced the idea was
to register a single callback for the ZPL. The ARC could invoke this
call back if it needed the ZPL to drop dentries, inodes, or other
cache objects which might be pinning buffers in the ARC. The ZPL
would iterate over all ZFS super blocks and perform the reclaim.
For the most part this design has worked well but due to limitations
in 2.6.35 and earlier kernels there were some problems. This patch
is designed to address those issues.
1) iterate_supers_type() is not provided by all kernels which makes
it impossible to safely iterate over all zpl_fs_type filesystems in
a single callback. The most straight forward and portable way to
resolve this is to register a callback per-filesystem during mount.
The arc_*_prune_callback() functions have always supported multiple
callbacks so this is functionally a very small change.
2) Commit 050d22b removed the non-portable shrink_dcache_memory()
and shrink_icache_memory() functions and didn't replace them with
equivalent functionality. This meant that for Linux 3.1 and older
kernels the ARC had no mechanism to drop dentries and inodes from
the caches if needed. This patch adds that missing functionality
by calling shrink_dcache_parent() to release dentries which may be
pinning inodes. This will result in all unused cache entries being
dropped which is a bit heavy handed but it's the only interface
available for old kernels.
3) A zpl_drop_inode() callback is registered for kernels older than
2.6.35 which do not support the .evict_inode callback. This ensures
that when the last reference on an inode is dropped it is immediately
removed from the cache. If this isn't done than inode can end up on
the global unused LRU with no mechanism available to ZFS to drop them.
Since the ARC buffers are not dropped the hottest inodes can still
be recreated without performing disk IO.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Issue #3160
The extra one was under the 'zfs receive' command (which isn't relevant).
Instead, it should have been further up (still in the 'zfs send' option).
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3194
Long ago the zio_bulk_flags module parameter was introduced to
facilitate debugging and profiling the zio_buf_caches. Today
this code works well and there's no compelling reason to keep
this functionality. In fact it's preferable to revert this so
the code is more consistent with other ZFS implementations.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Issue #3063
Add a table describing the debugging flags that can be set in the zfs_flags
module parameter. Also change the module_param type to 'uint' so users aren't
shown a negative value. The updated man page text is reproduced below for
convenience.
zfs_flags (int)
Set additional debugging flags. The following flags may be
bitwise-or'd together.
+-------------------------------------------------------+
|Value Symbolic Name |
| Description |
+-------------------------------------------------------+
| 1 ZFS_DEBUG_DPRINTF |
| Enable dprintf entries in the debug log. |
+-------------------------------------------------------+
| 2 ZFS_DEBUG_DBUF_VERIFY * |
| Enable extra dbuf verifications. |
+-------------------------------------------------------+
| 4 ZFS_DEBUG_DNODE_VERIFY * |
| Enable extra dnode verifications. |
+-------------------------------------------------------+
| 8 ZFS_DEBUG_SNAPNAMES |
| Enable snapshot name verification. |
+-------------------------------------------------------+
| 16 ZFS_DEBUG_MODIFY |
| Check for illegally modified ARC buffers. |
+-------------------------------------------------------+
| 32 ZFS_DEBUG_SPA |
| Enable spa_dbgmsg entries in the debug log. |
+-------------------------------------------------------+
| 64 ZFS_DEBUG_ZIO_FREE |
| Enable verification of block frees. |
+-------------------------------------------------------+
| 128 ZFS_DEBUG_HISTOGRAM_VERIFY |
| Enable extra spacemap histogram verifications. |
+-------------------------------------------------------+
* Requires debug build.
Default value: 0.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2988
Reviewed by Matthew Ahrens <mahrens@delphix.com>
Reviewed by Saso Kiselkov <skiselkov.ml@gmail.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>
References:
https://github.com/illumos/illumos-gate/commit/b8289d2https://www.illumos.org/issues/3756
Porting notes:
The static function zfs_prop_activate_feature() was removed because
this change removes the only caller. The function was not removed
from Illumos but instead left as dead code. However, to keep gcc
happy it was removed from Linux and may be easily restored if needed.
Ported by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1540
Users intending to use dedup should be clearly advised about
its memory requirements and the risks involved.
Thanx to Sachiru for comments and suggestions.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2754
