btrfs-progs/kernel-shared/delayed-ref.h

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2008 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef BTRFS_DELAYED_REF_H
#define BTRFS_DELAYED_REF_H
#include "kerncompat.h"
#include <stdbool.h>
#include "kernel-lib/list.h"
#include "kernel-lib/rbtree_types.h"
#include "kernel-lib/bitops.h"
#include "kernel-shared/ctree.h"
#include "kernel-shared/uapi/btrfs_tree.h"
struct btrfs_trans_handle;
struct btrfs_block_rsv;
/* these are the possible values of struct btrfs_delayed_ref_node->action */
enum btrfs_delayed_ref_action {
/* Add one backref to the tree */
BTRFS_ADD_DELAYED_REF = 1,
/* Delete one backref from the tree */
BTRFS_DROP_DELAYED_REF,
/* Record a full extent allocation */
BTRFS_ADD_DELAYED_EXTENT,
/* Not changing ref count on head ref */
BTRFS_UPDATE_DELAYED_HEAD,
} __attribute__ ((__packed__));
struct btrfs_delayed_ref_node {
struct rb_node ref_node;
/*
* If action is BTRFS_ADD_DELAYED_REF, also link this node to
* ref_head->ref_add_list, then we do not need to iterate the
* whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes.
*/
struct list_head add_list;
/* the starting bytenr of the extent */
u64 bytenr;
/* the size of the extent */
u64 num_bytes;
/* seq number to keep track of insertion order */
u64 seq;
/* ref count on this data structure */
refcount_t refs;
/*
* how many refs is this entry adding or deleting. For
* head refs, this may be a negative number because it is keeping
* track of the total mods done to the reference count.
* For individual refs, this will always be a positive number
*
* It may be more than one, since it is possible for a single
* parent to have more than one ref on an extent
*/
int ref_mod;
unsigned int action:8;
unsigned int type:8;
/* is this node still in the rbtree? */
unsigned int is_head:1;
unsigned int in_tree:1;
};
struct btrfs_delayed_extent_op {
struct btrfs_disk_key key;
u8 level;
bool update_key;
bool update_flags;
bool is_data;
u64 flags_to_set;
};
/*
* the head refs are used to hold a lock on a given extent, which allows us
* to make sure that only one process is running the delayed refs
* at a time for a single extent. They also store the sum of all the
* reference count modifications we've queued up.
*/
struct btrfs_delayed_ref_head {
u64 bytenr;
u64 num_bytes;
/*
* For insertion into struct btrfs_delayed_ref_root::href_root.
* Keep it in the same cache line as 'bytenr' for more efficient
* searches in the rbtree.
*/
struct rb_node href_node;
/*
* the mutex is held while running the refs, and it is also
* held when checking the sum of reference modifications.
*/
struct mutex mutex;
refcount_t refs;
/* Protects 'ref_tree' and 'ref_add_list'. */
spinlock_t lock;
struct rb_root ref_tree;
/* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */
struct list_head ref_add_list;
struct btrfs_delayed_extent_op *extent_op;
/*
* This is used to track the final ref_mod from all the refs associated
* with this head ref, this is not adjusted as delayed refs are run,
* this is meant to track if we need to do the csum accounting or not.
*/
int total_ref_mod;
/*
* This is the current outstanding mod references for this bytenr. This
* is used with lookup_extent_info to get an accurate reference count
* for a bytenr, so it is adjusted as delayed refs are run so that any
* on disk reference count + ref_mod is accurate.
*/
int ref_mod;
/*
* when a new extent is allocated, it is just reserved in memory
* The actual extent isn't inserted into the extent allocation tree
* until the delayed ref is processed. must_insert_reserved is
* used to flag a delayed ref so the accounting can be updated
* when a full insert is done.
*
* It is possible the extent will be freed before it is ever
* inserted into the extent allocation tree. In this case
* we need to update the in ram accounting to properly reflect
* the free has happened.
*/
bool must_insert_reserved;
bool is_data;
bool is_system;
bool processing;
};
struct btrfs_delayed_tree_ref {
struct btrfs_delayed_ref_node node;
u64 root;
u64 parent;
int level;
};
struct btrfs_delayed_data_ref {
struct btrfs_delayed_ref_node node;
u64 root;
u64 parent;
u64 objectid;
u64 offset;
};
enum btrfs_delayed_ref_flags {
/* Indicate that we are flushing delayed refs for the commit */
BTRFS_DELAYED_REFS_FLUSHING,
};
struct btrfs_delayed_ref_root {
/* head ref rbtree */
struct rb_root href_root;
/* dirty extent records */
struct rb_root dirty_extent_root;
/* this spin lock protects the rbtree and the entries inside */
spinlock_t lock;
/* how many delayed ref updates we've queued, used by the
* throttling code
*/
atomic_t num_entries;
/* total number of head nodes in tree */
unsigned long num_heads;
/* total number of head nodes ready for processing */
unsigned long num_heads_ready;
u64 pending_csums;
unsigned long flags;
u64 run_delayed_start;
/*
* To make qgroup to skip given root.
* This is for snapshot, as btrfs_qgroup_inherit() will manually
* modify counters for snapshot and its source, so we should skip
* the snapshot in new_root/old_roots or it will get calculated twice
*/
u64 qgroup_to_skip;
};
enum btrfs_ref_type {
BTRFS_REF_NOT_SET,
BTRFS_REF_DATA,
BTRFS_REF_METADATA,
BTRFS_REF_LAST,
} __attribute__((__packed__));
struct btrfs_data_ref {
/* For EXTENT_DATA_REF */
/* Original root this data extent belongs to */
u64 owning_root;
/* Inode which refers to this data extent */
u64 ino;
/*
* file_offset - extent_offset
*
* file_offset is the key.offset of the EXTENT_DATA key.
* extent_offset is btrfs_file_extent_offset() of the EXTENT_DATA data.
*/
u64 offset;
};
struct btrfs_tree_ref {
/*
* Level of this tree block
*
* Shared for skinny (TREE_BLOCK_REF) and normal tree ref.
*/
int level;
/*
* Root which owns this tree block.
*
* For TREE_BLOCK_REF (skinny metadata, either inline or keyed)
*/
u64 owning_root;
/* For non-skinny metadata, no special member needed */
};
struct btrfs_ref {
enum btrfs_ref_type type;
enum btrfs_delayed_ref_action action;
/*
* Whether this extent should go through qgroup record.
*
* Normally false, but for certain cases like delayed subtree scan,
* setting this flag can hugely reduce qgroup overhead.
*/
bool skip_qgroup;
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
/* Through which root is this modification. */
u64 real_root;
#endif
u64 bytenr;
u64 len;
/* Bytenr of the parent tree block */
u64 parent;
union {
struct btrfs_data_ref data_ref;
struct btrfs_tree_ref tree_ref;
};
};
extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
int __init btrfs_delayed_ref_init(void);
void __cold btrfs_delayed_ref_exit(void);
static inline void btrfs_init_generic_ref(struct btrfs_ref *generic_ref,
int action, u64 bytenr, u64 len, u64 parent)
{
generic_ref->action = action;
generic_ref->bytenr = bytenr;
generic_ref->len = len;
generic_ref->parent = parent;
}
static inline void btrfs_init_tree_ref(struct btrfs_ref *generic_ref,
int level, u64 root, u64 mod_root, bool skip_qgroup)
{
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
/* If @real_root not set, use @root as fallback */
generic_ref->real_root = mod_root ?: root;
#endif
generic_ref->tree_ref.level = level;
generic_ref->tree_ref.owning_root = root;
generic_ref->type = BTRFS_REF_METADATA;
if (skip_qgroup || !(is_fstree(root) &&
(!mod_root || is_fstree(mod_root))))
generic_ref->skip_qgroup = true;
else
generic_ref->skip_qgroup = false;
}
static inline void btrfs_init_data_ref(struct btrfs_ref *generic_ref,
u64 ref_root, u64 ino, u64 offset, u64 mod_root,
bool skip_qgroup)
{
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
/* If @real_root not set, use @root as fallback */
generic_ref->real_root = mod_root ?: ref_root;
#endif
generic_ref->data_ref.owning_root = ref_root;
generic_ref->data_ref.ino = ino;
generic_ref->data_ref.offset = offset;
generic_ref->type = BTRFS_REF_DATA;
if (skip_qgroup || !(is_fstree(ref_root) &&
(!mod_root || is_fstree(mod_root))))
generic_ref->skip_qgroup = true;
else
generic_ref->skip_qgroup = false;
}
static inline struct btrfs_delayed_extent_op *
btrfs_alloc_delayed_extent_op(void)
{
return kmalloc(sizeof(struct btrfs_delayed_extent_op), GFP_KERNEL);
}
static inline void
btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
{
if (op)
kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
}
static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
{
WARN_ON(refcount_read(&ref->refs) == 0);
if (refcount_dec_and_test(&ref->refs)) {
WARN_ON(ref->in_tree);
switch (ref->type) {
case BTRFS_TREE_BLOCK_REF_KEY:
case BTRFS_SHARED_BLOCK_REF_KEY:
kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
break;
case BTRFS_EXTENT_DATA_REF_KEY:
case BTRFS_SHARED_DATA_REF_KEY:
kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
break;
default:
BUG();
}
}
}
static inline u64 btrfs_ref_head_to_space_flags(
struct btrfs_delayed_ref_head *head_ref)
{
if (head_ref->is_data)
return BTRFS_BLOCK_GROUP_DATA;
else if (head_ref->is_system)
return BTRFS_BLOCK_GROUP_SYSTEM;
return BTRFS_BLOCK_GROUP_METADATA;
}
static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head)
{
if (refcount_dec_and_test(&head->refs))
kmem_cache_free(btrfs_delayed_ref_head_cachep, head);
}
int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, u64 parent,
u64 ref_root, int level, int action,
struct btrfs_delayed_extent_op *extent_op,
int *old_ref_mod, int *new_ref_mod);
int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_ref *generic_ref,
u64 reserved);
int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
struct btrfs_delayed_extent_op *extent_op);
void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head);
struct btrfs_delayed_ref_head *
btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
u64 bytenr);
int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head);
static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
{
mutex_unlock(&head->mutex);
}
void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head);
struct btrfs_delayed_ref_head *
btrfs_select_ref_head(struct btrfs_trans_handle *trans);
int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq);
void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr);
void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans);
void btrfs_migrate_to_delayed_refs_rsv(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *src,
u64 num_bytes);
bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info);
/*
* helper functions to cast a node into its container
*/
static inline struct btrfs_delayed_tree_ref *
btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
{
return container_of(node, struct btrfs_delayed_tree_ref, node);
}
static inline struct btrfs_delayed_data_ref *
btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
{
return container_of(node, struct btrfs_delayed_data_ref, node);
}
int cleanup_ref_head(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_head *head);
void btrfs_destroy_delayed_refs(struct btrfs_trans_handle *trans);
#endif