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321f4992c1
We can reduce two members' size that in turn reduce size of struct btrfs_ref from 64 to 56 bytes. As the structure is often used as a local variable several functions reduce their stack usage. - make enum btrfs_ref_type packed, there are only 4 values - switch action and its values to a packed enum Final structure layout: struct btrfs_ref { enum btrfs_ref_type type; /* 0 1 */ enum btrfs_delayed_ref_action action; /* 1 1 */ bool skip_qgroup; /* 2 1 */ /* XXX 5 bytes hole, try to pack */ u64 bytenr; /* 8 8 */ u64 len; /* 16 8 */ u64 parent; /* 24 8 */ union { struct btrfs_data_ref data_ref; /* 32 24 */ struct btrfs_tree_ref tree_ref; /* 32 16 */ }; /* 32 24 */ /* size: 56, cachelines: 1, members: 7 */ /* sum members: 51, holes: 1, sum holes: 5 */ /* last cacheline: 56 bytes */ }; Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
435 lines
12 KiB
C
435 lines
12 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*/
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#ifndef BTRFS_DELAYED_REF_H
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#define BTRFS_DELAYED_REF_H
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#include <linux/refcount.h>
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/* these are the possible values of struct btrfs_delayed_ref_node->action */
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enum btrfs_delayed_ref_action {
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/* Add one backref to the tree */
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BTRFS_ADD_DELAYED_REF = 1,
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/* Delete one backref from the tree */
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BTRFS_DROP_DELAYED_REF,
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/* Record a full extent allocation */
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BTRFS_ADD_DELAYED_EXTENT,
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/* Not changing ref count on head ref */
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BTRFS_UPDATE_DELAYED_HEAD,
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} __packed;
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struct btrfs_delayed_ref_node {
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struct rb_node ref_node;
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/*
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* If action is BTRFS_ADD_DELAYED_REF, also link this node to
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* ref_head->ref_add_list, then we do not need to iterate the
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* whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes.
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*/
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struct list_head add_list;
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/* the starting bytenr of the extent */
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u64 bytenr;
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/* the size of the extent */
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u64 num_bytes;
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/* seq number to keep track of insertion order */
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u64 seq;
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/* ref count on this data structure */
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refcount_t refs;
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/*
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* how many refs is this entry adding or deleting. For
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* head refs, this may be a negative number because it is keeping
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* track of the total mods done to the reference count.
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* For individual refs, this will always be a positive number
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*
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* It may be more than one, since it is possible for a single
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* parent to have more than one ref on an extent
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*/
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int ref_mod;
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unsigned int action:8;
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unsigned int type:8;
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};
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struct btrfs_delayed_extent_op {
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struct btrfs_disk_key key;
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u8 level;
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bool update_key;
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bool update_flags;
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u64 flags_to_set;
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};
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/*
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* the head refs are used to hold a lock on a given extent, which allows us
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* to make sure that only one process is running the delayed refs
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* at a time for a single extent. They also store the sum of all the
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* reference count modifications we've queued up.
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*/
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struct btrfs_delayed_ref_head {
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u64 bytenr;
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u64 num_bytes;
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/*
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* For insertion into struct btrfs_delayed_ref_root::href_root.
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* Keep it in the same cache line as 'bytenr' for more efficient
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* searches in the rbtree.
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*/
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struct rb_node href_node;
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/*
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* the mutex is held while running the refs, and it is also
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* held when checking the sum of reference modifications.
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*/
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struct mutex mutex;
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refcount_t refs;
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/* Protects 'ref_tree' and 'ref_add_list'. */
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spinlock_t lock;
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struct rb_root_cached ref_tree;
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/* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */
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struct list_head ref_add_list;
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struct btrfs_delayed_extent_op *extent_op;
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/*
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* This is used to track the final ref_mod from all the refs associated
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* with this head ref, this is not adjusted as delayed refs are run,
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* this is meant to track if we need to do the csum accounting or not.
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*/
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int total_ref_mod;
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/*
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* This is the current outstanding mod references for this bytenr. This
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* is used with lookup_extent_info to get an accurate reference count
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* for a bytenr, so it is adjusted as delayed refs are run so that any
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* on disk reference count + ref_mod is accurate.
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*/
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int ref_mod;
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/*
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* when a new extent is allocated, it is just reserved in memory
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* The actual extent isn't inserted into the extent allocation tree
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* until the delayed ref is processed. must_insert_reserved is
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* used to flag a delayed ref so the accounting can be updated
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* when a full insert is done.
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*
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* It is possible the extent will be freed before it is ever
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* inserted into the extent allocation tree. In this case
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* we need to update the in ram accounting to properly reflect
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* the free has happened.
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*/
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bool must_insert_reserved;
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bool is_data;
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bool is_system;
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bool processing;
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};
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struct btrfs_delayed_tree_ref {
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struct btrfs_delayed_ref_node node;
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u64 root;
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u64 parent;
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int level;
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};
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struct btrfs_delayed_data_ref {
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struct btrfs_delayed_ref_node node;
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u64 root;
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u64 parent;
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u64 objectid;
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u64 offset;
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};
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enum btrfs_delayed_ref_flags {
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/* Indicate that we are flushing delayed refs for the commit */
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BTRFS_DELAYED_REFS_FLUSHING,
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};
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struct btrfs_delayed_ref_root {
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/* head ref rbtree */
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struct rb_root_cached href_root;
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/* dirty extent records */
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struct rb_root dirty_extent_root;
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/* this spin lock protects the rbtree and the entries inside */
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spinlock_t lock;
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/* how many delayed ref updates we've queued, used by the
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* throttling code
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*/
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atomic_t num_entries;
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/* total number of head nodes in tree */
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unsigned long num_heads;
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/* total number of head nodes ready for processing */
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unsigned long num_heads_ready;
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u64 pending_csums;
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unsigned long flags;
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u64 run_delayed_start;
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/*
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* To make qgroup to skip given root.
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* This is for snapshot, as btrfs_qgroup_inherit() will manually
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* modify counters for snapshot and its source, so we should skip
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* the snapshot in new_root/old_roots or it will get calculated twice
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*/
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u64 qgroup_to_skip;
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};
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enum btrfs_ref_type {
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BTRFS_REF_NOT_SET,
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BTRFS_REF_DATA,
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BTRFS_REF_METADATA,
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BTRFS_REF_LAST,
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} __packed;
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struct btrfs_data_ref {
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/* For EXTENT_DATA_REF */
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/* Original root this data extent belongs to */
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u64 owning_root;
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/* Inode which refers to this data extent */
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u64 ino;
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/*
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* file_offset - extent_offset
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*
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* file_offset is the key.offset of the EXTENT_DATA key.
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* extent_offset is btrfs_file_extent_offset() of the EXTENT_DATA data.
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*/
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u64 offset;
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};
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struct btrfs_tree_ref {
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/*
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* Level of this tree block
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*
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* Shared for skinny (TREE_BLOCK_REF) and normal tree ref.
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*/
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int level;
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/*
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* Root which owns this tree block.
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*
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* For TREE_BLOCK_REF (skinny metadata, either inline or keyed)
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*/
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u64 owning_root;
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/* For non-skinny metadata, no special member needed */
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};
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struct btrfs_ref {
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enum btrfs_ref_type type;
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enum btrfs_delayed_ref_action action;
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/*
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* Whether this extent should go through qgroup record.
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*
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* Normally false, but for certain cases like delayed subtree scan,
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* setting this flag can hugely reduce qgroup overhead.
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*/
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bool skip_qgroup;
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#ifdef CONFIG_BTRFS_FS_REF_VERIFY
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/* Through which root is this modification. */
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u64 real_root;
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#endif
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u64 bytenr;
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u64 len;
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/* Bytenr of the parent tree block */
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u64 parent;
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union {
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struct btrfs_data_ref data_ref;
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struct btrfs_tree_ref tree_ref;
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};
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};
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extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
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extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
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extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
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extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
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int __init btrfs_delayed_ref_init(void);
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void __cold btrfs_delayed_ref_exit(void);
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static inline u64 btrfs_calc_delayed_ref_bytes(const struct btrfs_fs_info *fs_info,
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int num_delayed_refs)
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{
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u64 num_bytes;
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num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_delayed_refs);
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/*
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* We have to check the mount option here because we could be enabling
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* the free space tree for the first time and don't have the compat_ro
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* option set yet.
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*
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* We need extra reservations if we have the free space tree because
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* we'll have to modify that tree as well.
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*/
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if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
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num_bytes *= 2;
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return num_bytes;
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}
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static inline void btrfs_init_generic_ref(struct btrfs_ref *generic_ref,
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int action, u64 bytenr, u64 len, u64 parent)
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{
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generic_ref->action = action;
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generic_ref->bytenr = bytenr;
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generic_ref->len = len;
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generic_ref->parent = parent;
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}
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static inline void btrfs_init_tree_ref(struct btrfs_ref *generic_ref,
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int level, u64 root, u64 mod_root, bool skip_qgroup)
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{
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#ifdef CONFIG_BTRFS_FS_REF_VERIFY
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/* If @real_root not set, use @root as fallback */
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generic_ref->real_root = mod_root ?: root;
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#endif
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generic_ref->tree_ref.level = level;
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generic_ref->tree_ref.owning_root = root;
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generic_ref->type = BTRFS_REF_METADATA;
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if (skip_qgroup || !(is_fstree(root) &&
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(!mod_root || is_fstree(mod_root))))
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generic_ref->skip_qgroup = true;
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else
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generic_ref->skip_qgroup = false;
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}
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static inline void btrfs_init_data_ref(struct btrfs_ref *generic_ref,
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u64 ref_root, u64 ino, u64 offset, u64 mod_root,
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bool skip_qgroup)
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{
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#ifdef CONFIG_BTRFS_FS_REF_VERIFY
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/* If @real_root not set, use @root as fallback */
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generic_ref->real_root = mod_root ?: ref_root;
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#endif
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generic_ref->data_ref.owning_root = ref_root;
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generic_ref->data_ref.ino = ino;
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generic_ref->data_ref.offset = offset;
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generic_ref->type = BTRFS_REF_DATA;
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if (skip_qgroup || !(is_fstree(ref_root) &&
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(!mod_root || is_fstree(mod_root))))
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generic_ref->skip_qgroup = true;
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else
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generic_ref->skip_qgroup = false;
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}
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static inline struct btrfs_delayed_extent_op *
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btrfs_alloc_delayed_extent_op(void)
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{
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return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
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}
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static inline void
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btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
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{
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if (op)
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kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
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}
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static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
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{
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WARN_ON(refcount_read(&ref->refs) == 0);
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if (refcount_dec_and_test(&ref->refs)) {
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WARN_ON(!RB_EMPTY_NODE(&ref->ref_node));
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switch (ref->type) {
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case BTRFS_TREE_BLOCK_REF_KEY:
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case BTRFS_SHARED_BLOCK_REF_KEY:
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kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
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break;
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case BTRFS_EXTENT_DATA_REF_KEY:
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case BTRFS_SHARED_DATA_REF_KEY:
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kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
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break;
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default:
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BUG();
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}
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}
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}
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static inline u64 btrfs_ref_head_to_space_flags(
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struct btrfs_delayed_ref_head *head_ref)
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{
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if (head_ref->is_data)
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return BTRFS_BLOCK_GROUP_DATA;
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else if (head_ref->is_system)
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return BTRFS_BLOCK_GROUP_SYSTEM;
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return BTRFS_BLOCK_GROUP_METADATA;
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}
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static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head)
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{
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if (refcount_dec_and_test(&head->refs))
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kmem_cache_free(btrfs_delayed_ref_head_cachep, head);
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}
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int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
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struct btrfs_ref *generic_ref,
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struct btrfs_delayed_extent_op *extent_op);
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int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
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struct btrfs_ref *generic_ref,
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u64 reserved);
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int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
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u64 bytenr, u64 num_bytes,
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struct btrfs_delayed_extent_op *extent_op);
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void btrfs_merge_delayed_refs(struct btrfs_fs_info *fs_info,
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struct btrfs_delayed_ref_root *delayed_refs,
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struct btrfs_delayed_ref_head *head);
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struct btrfs_delayed_ref_head *
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btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
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u64 bytenr);
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int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
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struct btrfs_delayed_ref_head *head);
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static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
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{
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mutex_unlock(&head->mutex);
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}
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void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
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struct btrfs_delayed_ref_head *head);
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struct btrfs_delayed_ref_head *btrfs_select_ref_head(
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struct btrfs_delayed_ref_root *delayed_refs);
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int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq);
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void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr);
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void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans);
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int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
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enum btrfs_reserve_flush_enum flush);
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void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info,
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u64 num_bytes);
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bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info);
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/*
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* helper functions to cast a node into its container
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*/
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static inline struct btrfs_delayed_tree_ref *
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btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
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{
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return container_of(node, struct btrfs_delayed_tree_ref, node);
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}
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static inline struct btrfs_delayed_data_ref *
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btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
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{
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return container_of(node, struct btrfs_delayed_data_ref, node);
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}
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#endif
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