Both DDT log and BRT counters we read on pool import and then only
append or overwrite in full blocks. We don't need them in DMU or
ARC caches. Fortunately we have DMU_UNCACHEDIO for this now.
Even more we don't need BRT in non-evictable metadata DMU caches,
since it will likely never fit there, while block the cache from
its original users. Since DMU_OT_IS_METADATA_CACHED() has no way
to differentiate the new metadata types, mark BRT with storage
type of DMU_OT_DDT_ZAP. As side effect it will also put it on
dedup device, but that should actually be right.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17875
Only used for a couple of debug assertions which had very little value.
Setting it required taking certain locks, so we can remove all that too.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Robert Evans <evansr@google.com>
Reviewed-by: Adam Moss <c@yotes.com>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#16297Closes#17652Closes#17658
dn_dirty_txg only existed for DNODE_IS_DIRTY(). In turn, that only
existed to ensure that a dnode was clean before making it eligible for
removal from the array of cached dnodes attached to the object 0 L0
dbuf.
dn_dirtycnt is enough to check that now, so use it directly and remove
the rest.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Robert Evans <evansr@google.com>
Reviewed-by: Adam Moss <c@yotes.com>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#16297Closes#17652Closes#17658
Usage zap's (DMU_*USED_OBJECT) are updated in syncing context via
do_userquota_cacheflush(). zap shrink triggers,
ASSERT(db->db_objset == dmu_objset_pool(db->db_objset)->dp_meta_objset
|| txg != spa_syncing_txg(dmu_objset_spa(db->db_objset)));
DMU_*USED_OBJECT are special object (DMU_OBJECT_IS_SPECIAL), gets
updated in syncing context only. So, relax assert for it.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jitendra Patidar <jitendra.patidar@nutanix.com>
Closes#17602
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/Closes#17591
Based on previous commit this implements `zfs rewrite -P` flag,
making ZFS to keep blocks logical birth times while rewriting
files. It should exclude the rewritten blocks from incremental
sends, snapshot diffs, etc. Snapshots space usage same time will
reflect the additional space usage from newly allocated blocks.
Since this begins to use new "rewrite" flag in the block pointers,
this commit introduces a new read-compatible per-dataset feature
physical_rewrite. It must be enabled for the command to not fail,
it is activated on first use and deactivated on deletion of the
last affected dataset.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17565
During regular block writes ZFS sets both logical and physical
birth times equal to the current TXG. During dedup and block
cloning logical birth time is still set to the current TXG, but
physical may be copied from the original block that was used.
This represents the fact that logically user data has changed,
but the physically it is the same old block.
But block rewrite introduces a new situation, when block is not
changed logically, but stored in a different place of the pool.
From ARC, scrub and some other perspectives this is a new block,
but for example for user applications or incremental replication
it is not. Somewhat similar thing happen during remap phase of
device removal, but in that case space blocks are still acounted
as allocated at their logical birth times.
This patch introduces a new "rewrite" flag in the block pointer
structure, allowing to differentiate physical rewrite (when the
block is actually reallocated at the physical birth time) from
the device reval case (when the logical birth time is used).
The new functionality is not used at this point, and the only
expected change is that error log is now kept in terms of physical
physical birth times, rather than logical, since if a block with
logged error was somehow rewritten, then the previous error does
not matter any more.
This change also introduces a new TRAVERSE_LOGICAL flag to the
traverse code, allowing zfs send, redact and diff to work in
context of logical birth times, ignoring physical-only rewrites.
It also changes nothing at this point due to lack of those writes,
but they will come in a following patch.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17565
Avoid calling dbuf_evict_one() from memory reclaim contexts (e.g. Linux
kswapd, FreeBSD pagedaemon). This prevents deadlock caused by reclaim
threads waiting for the dbuf hash lock in the call sequence:
dbuf_evict_one -> dbuf_destroy -> arc_buf_destroy
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Kaitlin Hoang <kthoang@amazon.com>
Closes#17561
Previous dmu_tx_count_clone() was broken, stating that cloning is
similar to free. While they might be from some points, cloning
is not net-free. It will likely consume space and memory, and
unlike free it will do it no matter whether the destination has
the blocks or not (usually not, so previous code did nothing).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#17431
dbuf_verify(): Don't need the lock, since we only compare pointers.
dbuf_findbp(): Don't need the lock, since aside of unneeded assert
we only produce the pointer, but don't de-reference it.
dnode_next_offset_level(): When working on top level indirection
should lock dnode buffer's db_rwlock, since it is our parent. If
dnode has no buffer, then it is meta-dnode or one of quotas and we
should lock the dataset's ds_bp_rwlock instead.
Reviewed-by: Alan Somers <asomers@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#17441
ARC target size might drop significantly under memory pressure,
especially if current ARC size was much smaller than the target.
Since dbuf cache size is a fraction of the target ARC size, it
might need eviction too. Aside of memory from the dbuf eviction
itself, it might help ARC by making more buffers evictable.
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#17314
Before Direct I/O was implemented, I've implemented lighter version
I called Uncached I/O. It uses normal DMU/ARC data path with some
optimizations, but evicts data from caches as soon as possible and
reasonable. Originally I wired it only to a primarycache property,
but now completing the integration all the way up to the VFS.
While Direct I/O has the lowest possible memory bandwidth usage,
it also has a significant number of limitations. It require I/Os
to be page aligned, does not allow speculative prefetch, etc. The
Uncached I/O does not have those limitations, but instead require
additional memory copy, though still one less than regular cached
I/O. As such it should fill the gap in between. Considering this
I've disabled annoying EINVAL errors on misaligned requests, adding
a tunable for those who wants to test their applications.
To pass the information between the layers I had to change a number
of APIs. But as side effect upper layers can now control not only
the caching, but also speculative prefetch. I haven't wired it to
VFS yet, since it require looking on some OS specifics. But while
there I've implemented speculative prefetch of indirect blocks for
Direct I/O, controllable via all the same mechanisms.
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Fixes#17027
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
db.db_mtx must be held any time that db.db_data is accessed. All of
these functions do have the lock held by a parent; add assertions to
ensure that it stays that way.
See https://github.com/openzfs/zfs/discussions/17118
* Refactor dbuf_read_bonus to make it obvious why db_rwlock isn't
required.
* Refactor dbuf_hold_copy to eliminate the db_rwlock
Copy data into the newly allocated buffer before assigning it to the db.
That way, there will be no need to take db->db_rwlock.
* Refactor dbuf_read_hole
In the case of an indirect hole, initialize the newly allocated buffer
before assigning it to the dmu_buf_impl_t.
Sponsored by: ConnectWise
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#17209
It's been dead ever since 5fa356ea44
Sponsored by: ConnectWise
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes#17119
dbuf_prefetch_impl() should look on level of current indirect, not
the target prefetch level. dbuf_prefetch_indirect_done() should
call dnode_level_is_l2cacheable() if we have dpa_dnode to pass it.
It should fix some both false positive and negative L2ARC caching.
While there, fix redacted feature activation assertions. One was
always true, while another could give false positive if dpa_dnode
is NULL.
George Amanakis <gamanakis@gmail.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#17204
The redundant_metadata setting in ZFS allows users to trade resilience
for performance and space savings. This applies to all data and metadata
blocks in zfs, with one exception: gang blocks. Gang blocks currently
just take the copies property of the IO being ganged and, if it's 1,
sets it to 2. This means that we always make at least two copies of a
gang header, which is good for resilience. However, if the users care
more about performance than resilience, their gang blocks will be even
more of a penalty than usual.
We add logic to calculate the number of gang headers copies directly,
and store it as a separate IO property. This is stored in the IO
properties and not calculated when we decide to gang because by that
point we may not have easy access to the relevant information about what
kind of block is being stored. We also check the redundant_metadata
property when doing so, and use that to decide whether to store an extra
copy of the gang headers, compared to the underlying blocks.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Signed-off-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Co-authored-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Sponsored-by: https://despairlabs.com/sponsor/
Signed-off-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Linux 6.12 has conflicting range_tree_{find,destroy,clear} symbols.
Signed-off-by: Ivan Volosyuk <Ivan.Volosyuk@gmail.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
In dbuf_sync_leaf, we clone the arc_buf in dr if we share it with db
except for overridden case. However, this exception causes a race where
dbuf_new_size could free the arc_buf after the last dereference of
*datap and causes use-after-free. We fix this by cloning the buf
regardless if it's overridden.
The race:
--
P0 P1
dbuf_hold_impl()
// dbuf_hold_copy passed
// because db_data_pending NULL
dbuf_sync_leaf()
// doesn't clone *datap
// *datap derefed to db_buf
dbuf_write(*datap)
dbuf_new_size()
dmu_buf_will_dirty()
dbuf_fix_old_data()
// alloc new buf for P0 dr
// but can't change *datap
arc_alloc_buf()
arc_buf_destroy()
// alloc new buf for db_buf
// and destroy old buf
dbuf_write() // continue
abd_get_from_buf(data->b_data,
arc_buf_size(data))
// use-after-free
--
Here's an example when it happens:
BUG: kernel NULL pointer dereference, address: 000000000000002e
RIP: 0010:arc_buf_size+0x1c/0x30 [zfs]
Call Trace:
dbuf_write+0x3ff/0x580 [zfs]
dbuf_sync_leaf+0x13c/0x530 [zfs]
dbuf_sync_list+0xbf/0x120 [zfs]
dnode_sync+0x3ea/0x7a0 [zfs]
sync_dnodes_task+0x71/0xa0 [zfs]
taskq_thread+0x2b8/0x4e0 [spl]
kthread+0x112/0x130
ret_from_fork+0x1f/0x30
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Co-authored-by: Chunwei Chen <david.chen@nutanix.com>
Closes#16854
Direct I/O implementation added condition to call dbuf_undirty()
only in case of block cloning. But the condition is not right if
the block is no longer dirty in this TXG, but still in DB_NOFILL
state. It resulted in block not reverting to DB_UNCACHED and
following NULL de-reference on attempt to access absent db_data.
While there, add assertions for db_data to make debugging easier.
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16829
Those values require global atomics to get current hash_elements
values in few of the hottest code paths, while in all the years I
never cared about it. If somebody wants, it should be easy to
get it by periodic sampling, since neither ARC header nor DBUF
counts change so fast that it would be difficult to catch.
For now I've left hash_elements_max kstat for ARC, since it was
used/reported by arc_summary and it would break older versions,
but now it just reports the current value.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16759
We are doing exactly the same checks around all brt_pending_add().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16740
Small block workloads may use a very large number of dirty records.
During simple block cloning test due to BRT still using 4KB blocks
I can easily see up to 2.5M of those used. Before this change
dbuf_dirty_record_t structures representing them were allocated via
kmem_zalloc(), that rounded their size up to 512 bytes.
Introduction of specialized kmem cache allows to reduce the size
from 512 to 408 bytes. Additionally, since override and raw params
in dirty records are mutually exclusive, puting them into a union
allows to reduce structure size down to 368 bytes, increasing the
saving to 28%, that can be a 0.5GB or more of RAM.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16694
Adding O_DIRECT support to ZFS to bypass the ARC for writes/reads.
O_DIRECT support in ZFS will always ensure there is coherency between
buffered and O_DIRECT IO requests. This ensures that all IO requests,
whether buffered or direct, will see the same file contents at all
times. Just as in other FS's , O_DIRECT does not imply O_SYNC. While
data is written directly to VDEV disks, metadata will not be synced
until the associated TXG is synced.
For both O_DIRECT read and write request the offset and request sizes,
at a minimum, must be PAGE_SIZE aligned. In the event they are not,
then EINVAL is returned unless the direct property is set to always (see
below).
For O_DIRECT writes:
The request also must be block aligned (recordsize) or the write
request will take the normal (buffered) write path. In the event that
request is block aligned and a cached copy of the buffer in the ARC,
then it will be discarded from the ARC forcing all further reads to
retrieve the data from disk.
For O_DIRECT reads:
The only alignment restrictions are PAGE_SIZE alignment. In the event
that the requested data is in buffered (in the ARC) it will just be
copied from the ARC into the user buffer.
For both O_DIRECT writes and reads the O_DIRECT flag will be ignored in
the event that file contents are mmap'ed. In this case, all requests
that are at least PAGE_SIZE aligned will just fall back to the buffered
paths. If the request however is not PAGE_SIZE aligned, EINVAL will
be returned as always regardless if the file's contents are mmap'ed.
Since O_DIRECT writes go through the normal ZIO pipeline, the
following operations are supported just as with normal buffered writes:
Checksum
Compression
Encryption
Erasure Coding
There is one caveat for the data integrity of O_DIRECT writes that is
distinct for each of the OS's supported by ZFS.
FreeBSD - FreeBSD is able to place user pages under write protection so
any data in the user buffers and written directly down to the
VDEV disks is guaranteed to not change. There is no concern
with data integrity and O_DIRECT writes.
Linux - Linux is not able to place anonymous user pages under write
protection. Because of this, if the user decides to manipulate
the page contents while the write operation is occurring, data
integrity can not be guaranteed. However, there is a module
parameter `zfs_vdev_direct_write_verify` that controls the
if a O_DIRECT writes that can occur to a top-level VDEV before
a checksum verify is run before the contents of the I/O buffer
are committed to disk. In the event of a checksum verification
failure the write will return EIO. The number of O_DIRECT write
checksum verification errors can be observed by doing
`zpool status -d`, which will list all verification errors that
have occurred on a top-level VDEV. Along with `zpool status`, a
ZED event will be issues as `dio_verify` when a checksum
verification error occurs.
ZVOLs and dedup is not currently supported with Direct I/O.
A new dataset property `direct` has been added with the following 3
allowable values:
disabled - Accepts O_DIRECT flag, but silently ignores it and treats
the request as a buffered IO request.
standard - Follows the alignment restrictions outlined above for
write/read IO requests when the O_DIRECT flag is used.
always - Treats every write/read IO request as though it passed
O_DIRECT and will do O_DIRECT if the alignment restrictions
are met otherwise will redirect through the ARC. This
property will not allow a request to fail.
There is also a module parameter zfs_dio_enabled that can be used to
force all reads and writes through the ARC. By setting this module
parameter to 0, it mimics as if the direct dataset property is set to
disabled.
Reviewed-by: Brian Behlendorf <behlendorf@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Co-authored-by: Mark Maybee <mark.maybee@delphix.com>
Co-authored-by: Matt Macy <mmacy@FreeBSD.org>
Co-authored-by: Brian Behlendorf <behlendorf@llnl.gov>
Closes#10018
dmu_buf_will_clone() calls arc_buf_destroy() if there is an associated
ARC buffer with the dbuf. However, this can only be done conditionally.
If the previous dirty record's dr_data is pointed at db_dbf then
destroying it can lead to NULL pointer deference when syncing out the
previous dirty record.
This updates dmu_buf_fill_clone() to only call arc_buf_destroy() if the
previous dirty records dr_data is not pointing to db_buf. The block
clone wil still set the dbuf's db_buf and db_data to NULL, but this will
not cause any issues as any previous dirty record dr_data will still be
pointing at the ARC buffer.
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes#16337
Neither FreeBSD nor Linux currently implement kmem_cache_set_move(),
which means dnode_move() is never called. In such situation use of
dnode handles with respective locking to access dnode from dbuf is
a waste of time for no benefit.
This patch implements optional simplified code for such platforms,
saving at least 3 dnode lock/dereference/unlock per dbuf life cycle.
Originally I hoped to drop the handles completely to save memory,
but they are still used in dnodes allocation code, so left for now.
Before this change in CPU profiles of some workloads I saw 4-20% of
CPU time spent in zrl_add_impl()/zrl_remove(), which are gone now.
Reviewed-by: Rob Wing <rob.wing@klarasystems.com
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16374
- Use the macros in few places it was missed.
- Reduce scope of DB_DNODE_ENTER/EXIT() and inline some DB_DNODE()
uses to make it more obvious what exactly is protected there and
make unprotected accesses by mistake more difficult.
- Make use of zrl_owner().
Reviewed-by: Rob Wing <rob.wing@klarasystems.com
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16374
In case of error dmu_buf_fill_done() returns the buffer back into
DB_UNCACHED state. Since during transition from DB_UNCACHED into
DB_FILL state dbuf_noread() allocates an ARC buffer, we must free
it here, otherwise it will be leaked.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15665Closes#15802Closes#16216
In 92dc4ad83 I updated the dbuf_cache accounting to track the size of
userdata associated with dbufs. This adds the size of the dbuf+userdata
together in a single call to zfs_refcount_add_many(), but sometime
removes them in separate calls to zfs_refcount_remove_many(), if dbuf
and userdata are evicted separately.
What I didn't realise is that when refcount tracking is on,
zfs_refcount_add_many() and zfs_refcount_remove_many() are expected to
be paired, with their second & third args (count & holder) the same on
both sides. Splitting the remove part into two calls means the counts
don't match up, tripping a panic.
This commit fixes that, by always adding and removing the dbuf and
userdata counts separately.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reported-by: Mark Johnston <markj@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#16191
When running a debug kernel with lockdep enabled there
are several locks which report false positives. Set
MUTEX_NOLOCKDEP/RW_NOLOCKDEP to disable these warnings.
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#16188
In dbuf_read_verify_dnode_crypt():
- We don't need original dbuf locked there. Instead take a lock
on a dnode dbuf, that is actually manipulated.
- Block decryption for a dnode dbuf if it is currently being
written. ARC hash lock does not protect anonymous buffers, so
arc_untransform() is unsafe when used on buffers being written,
that may happen in case of encrypted dnode buffers, since they
are not copied by dbuf_dirty()/dbuf_hold_copy().
In dbuf_read():
- If the buffer is in flight, recheck its compression/encryption
status after it is cached, since it may need arc_untransform().
Tested-by: Rich Ercolani <rincebrain@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16104
Previous code held ARC state sublist lock throughout all L2ARC
write process, which included number of allocations and even ZIO
issues. Being blocked in any of those places the code could also
block ARC eviction, that could cause OOM activation or even dead-
lock if system is low on memory or one is too fragmented.
Fix it by dropping the lock as soon as we see a block eligible
for L2ARC writing and pick it up later using earlier inserted
marker. While there, also reduce scope of hash lock, moving
ZIO allocation and other operations not requiring header access
out of it. All operations requiring header access move under
hash lock, since L2_WRITING flag does not prevent header eviction
only transition to arc_l2c_only state with L1 header.
To be able to manipulate sublist lock and marker as needed add few
more multilist functions and modify one.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16040
Syncing context should not depend on current state of dbuf, which
could already change several times in later transaction groups,
but rely solely on dirty record for the transaction group being
synced. Some of the checks seem already impossible, while instead
of others I think we should better check for absence of data in
the specific dirty record rather than DB_NOFILL.
Reviewed-by: Robert Evans <evansr@google.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16057
Investigating read errors triggering panic fixed in #16042 I've
found that we have a race in a sync process between the moment
dirty record for cloned block is removed and the moment dbuf is
destroyed. If dmu_buf_hold_array_by_dnode() take a hold on a
cloned dbuf before it is synced/destroyed, then dbuf_read_impl()
may see it still in DB_NOFILL state, but without the dirty record.
Such case is not an error, but equivalent to DB_UNCACHED, since
the dbuf block pointer is already updated by dbuf_write_ready().
Unfortunately it is impossible to safely change the dbuf state
to DB_UNCACHED there, since there may already be another cloning
in progress, that dropped dbuf lock before creating a new dirty
record, protected only by the range lock.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Robert Evans <evansr@google.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16052
Previous code reported non-ZIO errors only via return value, but
not via parent ZIO. It could cause NULL-dereference panics due
to dmu_buf_hold_array_by_dnode() ignoring the return value,
relying solely on parent ZIO status.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Reported by: Ameer Hamza <ahamza@ixsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#16042
There exist a couple of macros that are used to update the blkptr birth
times but they can often be confusing. For example, the
BP_PHYSICAL_BIRTH() macro will provide either the physical birth time
if it is set or else return back the logical birth time. The
complement to this macro is BP_SET_BIRTH() which will set the logical
birth time and set the physical birth time if they are not the same.
Consumers may get confused when they are trying to get the physical
birth time and use the BP_PHYSICAL_BIRTH() macro only to find out that
the logical birth time is what is actually returned.
This change cleans up these macros and makes them symmetrical. The same
functionally is preserved but the name is changed. Instead of calling
BP_PHYSICAL_BIRTH(), consumer can now call BP_GET_BIRTH(). In
additional to cleaning up this naming conventions, two new sets of
macros are introduced -- BP_[SET|GET]_LOGICAL_BIRTH() and
BP_[SET|GET]_PHYSICAL_BIRTH. These new macros allow the consumer to
get and set the specific birth time.
As part of the cleanup, the unused GRID macros have been removed and
that portion of the blkptr are currently unused.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
Closes#15962
Before this change ZAP called dnode_hold() for almost every block
access, that was clearly visible in profiler under heavy load, such
as BRT. This patch makes it always hold the dnode reference between
zap_lockdir() and zap_unlockdir(). It allows to avoid most of dnode
operations between those. It also adds several new _by_dnode() APIs
to ZAP and uses them in BRT code. Also adds dmu_prefetch_by_dnode()
variant and uses it in the ZAP code.
After this there remains only one call to dmu_buf_dnode_enter(),
which seems to be unneeded. So remove the call and the functions.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15951
While 763ca47 closes the situation of block cloning creating
unencrypted records in encrypted datasets, existing data still causes
panic on read. Setting zfs_recover bypasses this but at the cost of
potentially ignoring more serious issues.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Peredun <chris.peredun@ixsystems.com>
Closes#15677
When ZFS overwrites a whole block, it does not bother to read the
old content from disk. It is a good optimization, but if the buffer
fill fails due to page fault or something else, the buffer ends up
corrupted, neither keeping old content, nor getting the new one.
On FreeBSD this is additionally complicated by page faults being
blocked by VFS layer, always returning EFAULT on attempt to write
from mmap()'ed but not yet cached address range. Normally it is
not a big problem, since after original failure VFS will retry the
write after reading the required data. The problem becomes worse
in specific case when somebody tries to write into a file its own
mmap()'ed content from the same location. In that situation the
only copy of the data is getting corrupted on the page fault and
the following retries only fixate the status quo. Block cloning
makes this issue easier to reproduce, since it does not read the
old data, unlike traditional file copy, that may work by chance.
This patch provides the fill status to dmu_buf_fill_done(), that
in case of error can destroy the corrupted buffer as if no write
happened. One more complication in case of block cloning is that
if error is possible during fill, dmu_buf_will_fill() must read
the data via fall-back to dmu_buf_will_dirty(). It is required
to allow in case of error restoring the buffer to a state after
the cloning, not not before it, that would happen if we just call
dbuf_undirty().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15665
Block cloning normally creates dirty record without dr_data. But if
the block is read after cloning, it is moved into DB_CACHED state and
receives the data buffer. If after that we call dbuf_unoverride()
to convert the dirty record into normal write, we should give it the
data buffer from dbuf and release one.
Reviewed-by: Kay Pedersen <mail@mkwg.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15654Closes#15656
In some cases dbuf_assign_arcbuf() may be called on a block that
was recently cloned. If it happened in current TXG we must undo
the block cloning first, since the only one dirty record per TXG
can't and shouldn't mean both cloning and overwrite same time.
Reviewed-by: Kay Pedersen <mail@mkwg.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15653
Previously, dmu_buf_will_clone() would roll back any dirty record, but
would not clean out the modified data nor reset the state before
releasing the lock. That leaves the last-written data in db_data, but
the dbuf in the wrong state.
This is eventually corrected when the dbuf state is made NOFILL, and
dbuf_noread() called (which clears out the old data), but at this point
its too late, because the lock was already dropped with that invalid
state.
Any caller acquiring the lock before the call into
dmu_buf_will_not_fill() can find what appears to be a clean, readable
buffer, and would take the wrong state from it: it should be getting the
data from the cloned block, not from earlier (unwritten) dirty data.
Even after the state was switched to NOFILL, the old data was still not
cleaned out until dbuf_noread(), which is another gap for a caller to
take the lock and read the wrong data.
This commit fixes all this by properly cleaning up the previous state
and then setting the new state before dropping the lock. The
DBUF_VERIFY() calls confirm that the dbuf is in a valid state when the
lock is down.
Sponsored-by: Klara, Inc.
Sponsored-By: OpenDrives Inc.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Pawel Jakub Dawidek <pawel@dawidek.net>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#15566Closes#15526
Entries in the dbuf cache contribute only the size of the dbuf data to
the cache size. Attached "user" data is not counted. This can lead to
the data currently "owned" by the cache consuming more memory accounting
appears to show. In some cases (eg a metadnode data block with all child
dnode_t slots allocated), the actual size can be as much as 3x as what
the cache believes it to be.
This is arguably correct behaviour, as the cache is only tracking the
size of the dbuf data, not even the overhead of the dbuf_t. On the other
hand, in the above case of dnodes, evicting cached metadnode dbufs is
the only current way to reclaim the dnode objects, and can lead to the
situation where the dbuf cache appears to be comfortably within its
target memory window and yet is holding enormous amounts of slab memory
that cannot be reclaimed.
This commit adds a facility for a dbuf user to artificially inflate the
apparent size of the dbuf for caching purposes. This at least allows for
cache tuning to be adjusted to match something closer to the real memory
overhead.
metadnode dbufs carry a >1KiB allocation per dnode in their user data.
This informs the dbuf cache machinery of that fact, allowing it to make
better decisions when evicting dbufs.
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#15511
As part of transaction group commit, dsl_pool_sync() sequentially calls
dsl_dataset_sync() for each dirty dataset, which subsequently calls
dmu_objset_sync(). dmu_objset_sync() in turn uses up to 75% of CPU
cores to run sync_dnodes_task() in taskq threads to sync the dirty
dnodes (files).
There are two problems:
1. Each ZVOL in a pool is a separate dataset/objset having a single
dnode. This means the objsets are synchronized serially, which
leads to a bottleneck of ~330K blocks written per second per pool.
2. In the case of multiple dirty dnodes/files on a dataset/objset on a
big system they will be sync'd in parallel taskq threads. However,
it is inefficient to to use 75% of CPU cores of a big system to do
that, because of (a) bottlenecks on a single write issue taskq, and
(b) allocation throttling. In addition, if not for the allocation
throttling sorting write requests by bookmarks (logical address),
writes for different files may reach space allocators interleaved,
leading to unwanted fragmentation.
The solution to both problems is to always sync no more and (if
possible) no fewer dnodes at the same time than there are allocators
the pool.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Edmund Nadolski <edmund.nadolski@ixsystems.com>
Closes#15197
Building module/zfs/dbuf.c for 32-bit targets can result in a warning:
In file included from
/usr/src/sys/contrib/openzfs/include/sys/zfs_context.h:97,
from /usr/src/sys/contrib/openzfs/module/zfs/dbuf.c:32:
/usr/src/sys/contrib/openzfs/module/zfs/dbuf.c: In function
'dmu_buf_will_clone':
/usr/src/sys/contrib/openzfs/lib/libspl/include/assert.h:116:33: error:
cast from pointer to integer of different size
[-Werror=pointer-to-int-cast]
116 | const uint64_t __left = (uint64_t)(LEFT);
\
| ^
/usr/src/sys/contrib/openzfs/lib/libspl/include/assert.h:148:25: note:
in expansion of macro 'VERIFY0'
148 | #define ASSERT0 VERIFY0
| ^~~~~~~
/usr/src/sys/contrib/openzfs/module/zfs/dbuf.c:2704:9: note: in
expansion of macro 'ASSERT0'
2704 | ASSERT0(dbuf_find_dirty_eq(db, tx->tx_txg));
| ^~~~~~~
This is because dbuf_find_dirty_eq() returns a pointer, which if
pointers are 32-bit results in a warning about the cast to uint64_t.
Instead, use the ASSERT3P() macro, with == and NULL as second and third
arguments, which should work regardless of the target's bitness.
Reviewed-by: Kay Pedersen <mail@mkwg.de>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Dimitry Andric <dimitry@andric.com>
Closes#15224
