The security and ACL operations should all be performed atomically.
To accomplish this there would need to significant invasive changes
made to the common code base. For the moment it's desirable for
compatibility reasons to avoid this. Therefore the code has been
updated to attempt to unwind the operation in case of failure
rather than panic.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2445
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
The metaslab_min_alloc_size option is no longer used in the code.
This functionality was removed by commit f3a7f66 and the module
options should have been dropped at that time.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
With debugging enabled and depending on your kernel config, the size of
arc_buf_hdr_t can blow out the stack of arc_evict() and arc_evict_ghost()
to greater than 1024 bytes. Let's avoid this.
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3377
5349 verify that block pointer is plausible before reading
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Reviewed by: Xin Li <delphij@FreeBSD.org>
Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com>
Approved by: Gordon Ross <gwr@nexenta.com>
References:
https://www.illumos.org/issues/5349https://github.com/illumos/illumos-gate/commit/f63ab3d5
Porting notes:
* Several variable declarations were moved due to C style needs
Ported-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3373
By the time we're tearing down our superblock the VFS has started releasing
all our inodes/znodes. Some of this work may have been handed off to our
iput taskq so we need to wait for that work to complete. However the iput
from the taskq can itself result in additional work being added to the
taskq:
dsl_pool_iput_taskq
iput
iput_final
evict
destroy_inode
zpl_inode_destroy
zfs_inode_destroy
zfs_iput_async(ZTOI(zp->z_xattr_parent))
taskq_dispatch(dsl_pool_iput_taskq..., iput, ...)
Let's wait until all our znodes have been released.
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3281
5348 zio_checksum_error() only fills in info if ECKSUM
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5348https://github.com/illumos/illumos-gate/commit/373dc1cf
Ported-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3372
5808 spa_check_logs is not necessary on readonly pools
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Simon Klinkert <simon.klinkert@gmail.com>
Reviewed by: Will Andrews <will@freebsd.org>
Approved by: Gordon Ross <gwr@nexenta.com>
References:
https://www.illumos.org/issues/5808https://github.com/illumos/illumos-gate/commit/23367a2f
Ported-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3369
5814 bpobj_iterate_impl(): Close a refcount leak iterating on a sublist.
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Simon Klinkert <simon.klinkert@gmail.com>
Approved by: Gordon Ross <gwr@nexenta.com>
References:
https://www.illumos.org/issues/5814https://github.com/illumos/illumos-gate/commit/b67dde11
Ported-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3368
4951 ZFS administrative commands should use reserved space, not with ENOSPC
Reviewed by: John Kennedy <john.kennedy@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>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
https://www.illumos.org/issues/4373https://github.com/illumos/illumos-gate/commit/7d46dc6
Ported by: Brian Behlendorf <behlendorf1@llnl.gov>
3654 zdb should print number of ganged blocks
3656 remove unused function zap_cursor_move_to_key()
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Approved by: Garrett D'Amore <garrett@damore.org>
References:
https://www.illumos.org/issues/3654https://www.illumos.org/issues/3656https://github.com/illumos/illumos-gate/commit/d5ee8a1
Porting Notes:
3655 and 3657 were part of this commit but those hunks were dropped
since they apply to mdb.
Ported by: Brian Behlendorf <behlendorf1@llnl.gov>
It's been reported that threads would loop infinitely inside zfs_zget. The
speculated cause for this is that if an inode is marked for evict, zfs_zget
would see that and loop. However, if the looping thread doesn't yield, the
inode may not have a chance to finish evict, thus causing a infinite loop.
This patch solve this issue by add cond_resched to zfs_zget, making the
looping thread to yield when needed.
Tested-by: jlavoy <jalavoy@gmail.com>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3349
5244 zio pipeline callers should explicitly invoke next stage
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@gmail.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Approved by: Gordon Ross <gwr@nexenta.com>
References:
https://www.illumos.org/issues/5244https://github.com/illumos/illumos-gate/commit/738f37b
Porting Notes:
1. The unported "2932 support crash dumps to raidz, etc. pools"
caused a merge conflict due to a copyright difference in
module/zfs/vdev_raidz.c.
2. The unported "4128 disks in zpools never go away when pulled"
and additional Linux-specific changes caused merge conflicts in
module/zfs/vdev_disk.c.
Ported-by: Richard Yao <richard.yao@clusterhq.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2828
5812 assertion failed in zrl_tryenter(): zr_owner==NULL
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Reviewed by: Will Andrews <will@freebsd.org>
Approved by: Gordon Ross <gwr@nexenta.com>
References:
https://www.illumos.org/issues/5812https://github.com/illumos/illumos-gate/commit/8df1730
Ported-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3357
5592 NULL pointer dereference in dsl_prop_notify_all_cb()
Author: Justin T. Gibbs <justing@spectralogic.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Will Andrews <will@freebsd.org>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5592https://github.com/illumos/illumos-gate/commit/9d47dec
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5531 NULL pointer dereference in dsl_prop_get_ds()
Author: Justin T. Gibbs <justing@spectralogic.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5531https://github.com/illumos/illumos-gate/commit/e57a022
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5056 ZFS deadlock on db_mtx and dn_holds
Author: Justin Gibbs <justing@spectralogic.com>
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5056https://github.com/illumos/illumos-gate/commit/bc9014e
Porting Notes:
sa_handle_get_from_db():
- the original patch includes an otherwise unmentioned fix for a
possible usage of an uninitialised variable
dmu_objset_open_impl():
- Under Illumos list_link_init() is the same as filling a list_node_t
with NULLs, so they don't notice if they miss doing list_link_init()
on a zero'd containing structure (e.g. allocated with kmem_zalloc as
here). Under Linux, not so much: an uninitialised list_node_t goes
"Boom!" some time later when it's used or destroyed.
dmu_objset_evict_dbufs():
- reduce stack usage using kmem_alloc()
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
5095 panic when adding a duplicate dbuf to dn_dbufs
Author: Alex Reece <alex@delphix.com>
Reviewed by: Adam Leventhal <adam.leventhal@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Mattew Ahrens <mahrens@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Josef Sipek <jeffpc@josefsipek.net>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5095https://github.com/illumos/illumos-gate/commit/86bb58a
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
4873 zvol unmap calls can take a very long time for larger datasets
Author: Alex Reece <alex@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Basil Crow <basil.crow@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/4873https://github.com/illumos/illumos-gate/commit/0f6d88a
Porting Notes:
dbuf_free_range():
- reduce stack usage using kmem_alloc()
- the sorted AVL tree will handle the spill block case correctly
without all the special handling in the for() loop
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
3897 zfs filesystem and snapshot limits (fix leak)
Author: Alex Reece <alex.reece@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>
References:
https://www.illumos.org/issues/3897https://github.com/illumos/illumos-gate/commit/fb7001f
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
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>
In traverse_visitbp(), the input argument dnp is modified in the middle to
point to a temporary buffer. Originally this doesn't matter, because no user
of TRAVERSE_POST dereferences it. However, in fbeddd6 a piece of code is added
dereferencing dnp after the modification, creating a possible bug.
We fix this by creating a new local variable cdnp for the DMU_OT_DNODE case,
so we don't modify the input argument. Also we introduce different local
variables in the DMU_OT_OBJSET case to prevent confusion between the input
argument.
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2060
This isn't required for the Linux port because the kernel tracks
if a module is busy. The prototype for spa_busy() is also removed
since its definition was already removed.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3262
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Will Andrews <willa@SpectraLogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
References:
https://www.illumos.org/issues/5313https://github.com/illumos/illumos-gate/commit/fe319232
Ported-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3280
The function spa_add_feature_stats() manipulates the shared nvlist
spa->spa_feat_stats in an unsafe concurrent manner. Add a mutex to
protect the list.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3335
The following panic would occur under certain heavy load:
[ 4692.202686] Kernel panic - not syncing: thread ffff8800c4f5dd60 terminating with rrw lock ffff8800da1b9c40 held
[ 4692.228053] CPU: 1 PID: 6250 Comm: mmap_deadlock Tainted: P OE 3.18.10 #7
The culprit is that ZFS_EXIT(zsb) would call tsd_exit() every time, which
would purge all tsd data for the thread. However, ZFS_ENTER is designed to be
reentrant, so we cannot allow ZFS_EXIT to blindly purge tsd data.
Instead, we rely on the new behavior of tsd_set. When NULL is passed as the
new value to tsd_set, it will automatically remove the tsd entry specified the
the key for the current thread.
rrw_tsd_key and zfs_allow_log_key already calls tsd_set(key, NULL) when
they're done. The zfs_fsyncer_key relied on ZFS_EXIT(zsb) to call tsd_exit() to
do clean up. Now we explicitly call tsd_set(key, NULL) on them.
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3247
Additional testing has shown that the region covered by PF_FSTRANS
needs to be extended to cover the zpl_xattr_security_init() and
init_acl() functions. The zpl_mark_dirty() function can also recurse
and therefore must always be protected.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes#3331
Prevent deadlocks by disabling direct reclaim during all NFS, xattr,
ctldir, and super function calls. This is related to 40d06e3.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #3225
The Linux slab, in general, performs better than the SPl slab in cases
where a lot of objects are allocated and fragmentation is likely present.
This patch fixes pathologically bad behavior in cases where the ARC is
filled with mostly metadata and a user program needs to allocate and
dirty enough memory which would require an insignificant amount of the
ARC to be reclaimed.
If zfs_znode_cache is on the SPL slab, the system may spin for a very
long time trying to reclaim sufficient memory. If it is on the Linux
slab, the behavior has been observed to be much more predictible; the
memory is reclaimed more efficiently.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3283
The packed nvlist allocated in spa_config_write() may exceed the
warning threshold for large configurations. Use the vmem interfaces
for this short lived allocation.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3251
Prevent deadlocks by disabling direct reclaim during all ZPL and ioctl
calls as well as the l2arc and adapt ARC threads.
This obviates the need for MUTEX_FSTRANS so its previous uses and
definition have been eliminated.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3225
5693 ztest fails in dbuf_verify: buf[i] == 0, due to dedup and bp_override
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5693https://github.com/illumos/illumos-gate/commit/7f7ace3
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3231
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
Align code in traverse_visitbp() with that in Illumos in preparation for
applying Illumos-5694.
No functional change: use a temporary variable pd to replace multiple
occurrences of td->td_pfd. This increases our stack use slightly more
then normal because the function is called recursively.
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3230
5695 dmu_sync'ed holes do not retain birth time
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/5695https://github.com/illumos/illumos-gate/commit/70163ac
Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3229
When called to free a spill block from a dnode, dbuf_free_range() has a
bug that results in all dbufs for the dnode getting freed. A variety of
problems may result from this bug, but a common one was a zap lookup
tripping an ASSERT because the zap buffers had been zeroed out. This
could happen on a dataset with xattr=sa set when extended attributes are
written and removed on a directory concurrently with I/O to files in
that directory.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Fixes#3195Fixes#3204Fixes#3222
ZoL had been setting max_sectors to UINT_MAX, but until Linux 3.19, it
the kernel artifically capped it at 1024 (BLK_DEF_MAX_SECTORS).
This cap was removed in torvalds/linux@34b48db. This patch changes
it to DMU_MAX_ACCESS (in sectors) and also changes the ASSERT in
dmu_tx_hold_write() to allow the maximum transfer size.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3212
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
zfs_sb_t has grown to the point where using kmem_zalloc() for allocations
is triggering the 32k warning threshold.
We can't safely convert this entire allocation to use vmem_alloc() instead
of kmem_alloc() because the backing_dev_info structure is embedded here.
It depends on the bit_waitqueue() function which won't behave properly
when given a virtual address.
Instead, use vmem_alloc() to allocate the z_hold_mtx array separately.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Closes#3178
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 arc_meta_max value should be increased when space it consumed not when
it is returned. This ensure's that arc_meta_max is always up to date.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Issue #3160
