3ec3bc2167
Reviewed by: Steve Gonczi <steve.gonczi@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com> Ported-by: Brian Behlendorf <behlendorf1@llnl.gov> Background information: This assertion about tx_space_* verifies that we are not dirtying more stuff than we thought we would. We “need” to know how much we will dirty so that we can check if we should fail this transaction with ENOSPC/EDQUOT, in dmu_tx_assign(). While the transaction is open (i.e. between dmu_tx_assign() and dmu_tx_commit() — typically less than a millisecond), we call dbuf_dirty() on the exact blocks that will be modified. Once this happens, the temporary accounting in tx_space_* is unnecessary, because we know exactly what blocks are newly dirtied; we call dnode_willuse_space() to track this more exact accounting. The fundamental problem causing this bug is that dmu_tx_hold_*() relies on the current state in the DMU (e.g. dn_nlevels) to predict how much will be dirtied by this transaction, but this state can change before we actually perform the transaction (i.e. call dbuf_dirty()). This bug will be fixed by removing the assertion that the tx_space_* accounting is perfectly accurate (i.e. we never dirty more than was predicted by dmu_tx_hold_*()). By removing the requirement that this accounting be perfectly accurate, we can also vastly simplify it, e.g. removing most of the logic in dmu_tx_count_*(). The new tx space accounting will be very approximate, and may be more or less than what is actually dirtied. It will still be used to determine if this transaction will put us over quota. Transactions that are marked by dmu_tx_mark_netfree() will be excepted from this check. We won’t make an attempt to determine how much space will be freed by the transaction — this was rarely accurate enough to determine if a transaction should be permitted when we are over quota, which is why dmu_tx_mark_netfree() was introduced in 2014. We also won’t attempt to give “credit” when overwriting existing blocks, if those blocks may be freed. This allows us to remove the do_free_accounting logic in dbuf_dirty(), and associated routines. This logic attempted to predict what will be on disk when this txg syncs, to know if the overwritten block will be freed (i.e. exists, and has no snapshots). OpenZFS-issue: https://www.illumos.org/issues/7793 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3704e0a Upstream bugs: DLPX-32883a Closes #5804 Porting notes: - DNODE_SIZE replaced with DNODE_MIN_SIZE in dmu_tx_count_dnode(), Using the default dnode size would be slightly better. - DEBUG_DMU_TX wrappers and configure option removed. - Resolved _by_dnode() conflicts these changes have not yet been applied to OpenZFS.
288 lines
7.6 KiB
C
288 lines
7.6 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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/*
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* Copyright (c) 2012, Joyent, Inc. All rights reserved.
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* Copyright (c) 2013, 2015 by Delphix. All rights reserved.
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*/
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#ifndef _SYS_DMU_IMPL_H
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#define _SYS_DMU_IMPL_H
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#include <sys/txg_impl.h>
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#include <sys/zio.h>
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#include <sys/dnode.h>
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#include <sys/zfs_context.h>
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#include <sys/zfs_ioctl.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* This is the locking strategy for the DMU. Numbers in parenthesis are
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* cases that use that lock order, referenced below:
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*
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* ARC is self-contained
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* bplist is self-contained
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* refcount is self-contained
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* txg is self-contained (hopefully!)
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* zst_lock
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* zf_rwlock
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*
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* XXX try to improve evicting path?
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*
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* dp_config_rwlock > os_obj_lock > dn_struct_rwlock >
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* dn_dbufs_mtx > hash_mutexes > db_mtx > dd_lock > leafs
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*
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* dp_config_rwlock
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* must be held before: everything
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* protects dd namespace changes
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* protects property changes globally
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* held from:
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* dsl_dir_open/r:
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* dsl_dir_create_sync/w:
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* dsl_dir_sync_destroy/w:
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* dsl_dir_rename_sync/w:
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* dsl_prop_changed_notify/r:
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*
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* os_obj_lock
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* must be held before:
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* everything except dp_config_rwlock
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* protects os_obj_next
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* held from:
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* dmu_object_alloc: dn_dbufs_mtx, db_mtx, hash_mutexes, dn_struct_rwlock
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*
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* dn_struct_rwlock
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* must be held before:
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* everything except dp_config_rwlock and os_obj_lock
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* protects structure of dnode (eg. nlevels)
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* db_blkptr can change when syncing out change to nlevels
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* dn_maxblkid
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* dn_nlevels
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* dn_*blksz*
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* phys nlevels, maxblkid, physical blkptr_t's (?)
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* held from:
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* callers of dbuf_read_impl, dbuf_hold[_impl], dbuf_prefetch
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* dmu_object_info_from_dnode: dn_dirty_mtx (dn_datablksz)
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* dbuf_read_impl: db_mtx, dmu_zfetch()
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* dmu_zfetch: zf_rwlock/r, zst_lock, dbuf_prefetch()
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* dbuf_new_size: db_mtx
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* dbuf_dirty: db_mtx
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* dbuf_findbp: (callers, phys? - the real need)
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* dbuf_create: dn_dbufs_mtx, hash_mutexes, db_mtx (phys?)
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* dbuf_prefetch: dn_dirty_mtx, hash_mutexes, db_mtx, dn_dbufs_mtx
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* dbuf_hold_impl: hash_mutexes, db_mtx, dn_dbufs_mtx, dbuf_findbp()
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* dnode_sync/w (increase_indirection): db_mtx (phys)
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* dnode_set_blksz/w: dn_dbufs_mtx (dn_*blksz*)
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* dnode_new_blkid/w: (dn_maxblkid)
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* dnode_free_range/w: dn_dirty_mtx (dn_maxblkid)
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* dnode_next_offset: (phys)
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*
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* dn_dbufs_mtx
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* must be held before:
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* db_mtx, hash_mutexes
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* protects:
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* dn_dbufs
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* dn_evicted
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* held from:
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* dmu_evict_user: db_mtx (dn_dbufs)
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* dbuf_free_range: db_mtx (dn_dbufs)
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* dbuf_remove_ref: db_mtx, callees:
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* dbuf_hash_remove: hash_mutexes, db_mtx
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* dbuf_create: hash_mutexes, db_mtx (dn_dbufs)
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* dnode_set_blksz: (dn_dbufs)
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*
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* hash_mutexes (global)
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* must be held before:
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* db_mtx
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* protects dbuf_hash_table (global) and db_hash_next
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* held from:
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* dbuf_find: db_mtx
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* dbuf_hash_insert: db_mtx
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* dbuf_hash_remove: db_mtx
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*
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* db_mtx (meta-leaf)
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* must be held before:
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* dn_mtx, dn_dirty_mtx, dd_lock (leaf mutexes)
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* protects:
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* db_state
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* db_holds
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* db_buf
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* db_changed
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* db_data_pending
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* db_dirtied
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* db_link
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* db_dirty_node (??)
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* db_dirtycnt
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* db_d.*
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* db.*
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* held from:
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* dbuf_dirty: dn_mtx, dn_dirty_mtx
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* dbuf_dirty->dsl_dir_willuse_space: dd_lock
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* dbuf_dirty->dbuf_new_block->dsl_dataset_block_freeable: dd_lock
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* dbuf_undirty: dn_dirty_mtx (db_d)
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* dbuf_write_done: dn_dirty_mtx (db_state)
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* dbuf_*
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* dmu_buf_update_user: none (db_d)
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* dmu_evict_user: none (db_d) (maybe can eliminate)
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* dbuf_find: none (db_holds)
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* dbuf_hash_insert: none (db_holds)
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* dmu_buf_read_array_impl: none (db_state, db_changed)
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* dmu_sync: none (db_dirty_node, db_d)
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* dnode_reallocate: none (db)
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*
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* dn_mtx (leaf)
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* protects:
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* dn_dirty_dbufs
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* dn_ranges
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* phys accounting
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* dn_allocated_txg
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* dn_free_txg
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* dn_assigned_txg
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* dd_assigned_tx
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* dn_notxholds
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* dn_dirtyctx
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* dn_dirtyctx_firstset
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* (dn_phys copy fields?)
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* (dn_phys contents?)
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* held from:
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* dnode_*
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* dbuf_dirty: none
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* dbuf_sync: none (phys accounting)
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* dbuf_undirty: none (dn_ranges, dn_dirty_dbufs)
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* dbuf_write_done: none (phys accounting)
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* dmu_object_info_from_dnode: none (accounting)
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* dmu_tx_commit: none
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* dmu_tx_hold_object_impl: none
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* dmu_tx_try_assign: dn_notxholds(cv)
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* dmu_tx_unassign: none
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*
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* dd_lock
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* must be held before:
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* ds_lock
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* ancestors' dd_lock
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* protects:
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* dd_prop_cbs
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* dd_sync_*
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* dd_used_bytes
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* dd_tempreserved
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* dd_space_towrite
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* dd_myname
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* dd_phys accounting?
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* held from:
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* dsl_dir_*
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* dsl_prop_changed_notify: none (dd_prop_cbs)
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* dsl_prop_register: none (dd_prop_cbs)
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* dsl_prop_unregister: none (dd_prop_cbs)
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*
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* os_lock (leaf)
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* protects:
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* os_dirty_dnodes
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* os_free_dnodes
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* os_dnodes
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* os_downgraded_dbufs
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* dn_dirtyblksz
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* dn_dirty_link
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* held from:
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* dnode_create: none (os_dnodes)
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* dnode_destroy: none (os_dnodes)
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* dnode_setdirty: none (dn_dirtyblksz, os_*_dnodes)
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* dnode_free: none (dn_dirtyblksz, os_*_dnodes)
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*
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* ds_lock
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* protects:
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* ds_objset
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* ds_open_refcount
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* ds_snapname
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* ds_phys accounting
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* ds_phys userrefs zapobj
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* ds_reserved
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* held from:
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* dsl_dataset_*
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*
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* dr_mtx (leaf)
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* protects:
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* dr_children
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* held from:
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* dbuf_dirty
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* dbuf_undirty
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* dbuf_sync_indirect
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* dnode_new_blkid
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*/
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struct objset;
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struct dmu_pool;
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typedef struct dmu_xuio {
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int next;
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int cnt;
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struct arc_buf **bufs;
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iovec_t *iovp;
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} dmu_xuio_t;
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/*
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* The list of data whose inclusion in a send stream can be pending from
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* one call to backup_cb to another. Multiple calls to dump_free() and
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* dump_freeobjects() can be aggregated into a single DRR_FREE or
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* DRR_FREEOBJECTS replay record.
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*/
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typedef enum {
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PENDING_NONE,
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PENDING_FREE,
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PENDING_FREEOBJECTS
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} dmu_pendop_t;
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typedef struct dmu_sendarg {
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list_node_t dsa_link;
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dmu_replay_record_t *dsa_drr;
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vnode_t *dsa_vp;
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int dsa_outfd;
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proc_t *dsa_proc;
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offset_t *dsa_off;
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objset_t *dsa_os;
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zio_cksum_t dsa_zc;
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uint64_t dsa_toguid;
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int dsa_err;
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dmu_pendop_t dsa_pending_op;
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uint64_t dsa_featureflags;
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uint64_t dsa_last_data_object;
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uint64_t dsa_last_data_offset;
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uint64_t dsa_resume_object;
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uint64_t dsa_resume_offset;
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boolean_t dsa_sent_begin;
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boolean_t dsa_sent_end;
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} dmu_sendarg_t;
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void dmu_object_zapify(objset_t *, uint64_t, dmu_object_type_t, dmu_tx_t *);
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void dmu_object_free_zapified(objset_t *, uint64_t, dmu_tx_t *);
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int dmu_buf_hold_noread(objset_t *, uint64_t, uint64_t,
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void *, dmu_buf_t **);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _SYS_DMU_IMPL_H */
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