delayed-ref.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2009 Oracle.  All rights reserved.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include "messages.h"
#include "ctree.h"
#include "delayed-ref.h"
#include "transaction.h"
#include "qgroup.h"
#include "space-info.h"
#include "tree-mod-log.h"
#include "fs.h"

struct kmem_cache *btrfs_delayed_ref_head_cachep;
struct kmem_cache *btrfs_delayed_ref_node_cachep;
struct kmem_cache *btrfs_delayed_extent_op_cachep;
/*
 * delayed back reference update tracking.  For subvolume trees
 * we queue up extent allocations and backref maintenance for
 * delayed processing.   This avoids deep call chains where we
 * add extents in the middle of btrfs_search_slot, and it allows
 * us to buffer up frequently modified backrefs in an rb tree instead
 * of hammering updates on the extent allocation tree.
 */

bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info)
{ … }

/*
 * Release a ref head's reservation.
 *
 * @fs_info:  the filesystem
 * @nr_refs:  number of delayed refs to drop
 * @nr_csums: number of csum items to drop
 *
 * Drops the delayed ref head's count from the delayed refs rsv and free any
 * excess reservation we had.
 */
void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr_refs, int nr_csums)
{ … }

/*
 * Adjust the size of the delayed refs rsv.
 *
 * This is to be called anytime we may have adjusted trans->delayed_ref_updates
 * or trans->delayed_ref_csum_deletions, it'll calculate the additional size and
 * add it to the delayed_refs_rsv.
 */
void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans)
{ … }

/*
 * Adjust the size of the delayed refs block reserve for 1 block group item
 * insertion, used after allocating a block group.
 */
void btrfs_inc_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info)
{ … }

/*
 * Adjust the size of the delayed refs block reserve to release space for 1
 * block group item insertion.
 */
void btrfs_dec_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info)
{ … }

/*
 * Adjust the size of the delayed refs block reserve for 1 block group item
 * update.
 */
void btrfs_inc_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info)
{ … }

/*
 * Adjust the size of the delayed refs block reserve to release space for 1
 * block group item update.
 */
void btrfs_dec_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info)
{ … }

/*
 * Refill based on our delayed refs usage.
 *
 * @fs_info: the filesystem
 * @flush:   control how we can flush for this reservation.
 *
 * This will refill the delayed block_rsv up to 1 items size worth of space and
 * will return -ENOSPC if we can't make the reservation.
 */
int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info,
				  enum btrfs_reserve_flush_enum flush)
{ … }

/*
 * compare two delayed data backrefs with same bytenr and type
 */
static int comp_data_refs(struct btrfs_delayed_ref_node *ref1,
			  struct btrfs_delayed_ref_node *ref2)
{ … }

static int comp_refs(struct btrfs_delayed_ref_node *ref1,
		     struct btrfs_delayed_ref_node *ref2,
		     bool check_seq)
{ … }

/* insert a new ref to head ref rbtree */
static struct btrfs_delayed_ref_head *htree_insert(struct rb_root_cached *root,
						   struct rb_node *node)
{ … }

static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
		struct btrfs_delayed_ref_node *ins)
{ … }

static struct btrfs_delayed_ref_head *find_first_ref_head(
		struct btrfs_delayed_ref_root *dr)
{ … }

/*
 * Find a head entry based on bytenr. This returns the delayed ref head if it
 * was able to find one, or NULL if nothing was in that spot.  If return_bigger
 * is given, the next bigger entry is returned if no exact match is found.
 */
static struct btrfs_delayed_ref_head *find_ref_head(
		struct btrfs_delayed_ref_root *dr, u64 bytenr,
		bool return_bigger)
{ … }

int btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs,
			   struct btrfs_delayed_ref_head *head)
{ … }

static inline void drop_delayed_ref(struct btrfs_fs_info *fs_info,
				    struct btrfs_delayed_ref_root *delayed_refs,
				    struct btrfs_delayed_ref_head *head,
				    struct btrfs_delayed_ref_node *ref)
{ … }

static bool merge_ref(struct btrfs_fs_info *fs_info,
		      struct btrfs_delayed_ref_root *delayed_refs,
		      struct btrfs_delayed_ref_head *head,
		      struct btrfs_delayed_ref_node *ref,
		      u64 seq)
{ … }

void btrfs_merge_delayed_refs(struct btrfs_fs_info *fs_info,
			      struct btrfs_delayed_ref_root *delayed_refs,
			      struct btrfs_delayed_ref_head *head)
{ … }

int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
{ … }

struct btrfs_delayed_ref_head *btrfs_select_ref_head(
		struct btrfs_delayed_ref_root *delayed_refs)
{ … }

void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
			   struct btrfs_delayed_ref_head *head)
{ … }

/*
 * Helper to insert the ref_node to the tail or merge with tail.
 *
 * Return false if the ref was inserted.
 * Return true if the ref was merged into an existing one (and therefore can be
 * freed by the caller).
 */
static bool insert_delayed_ref(struct btrfs_trans_handle *trans,
			       struct btrfs_delayed_ref_head *href,
			       struct btrfs_delayed_ref_node *ref)
{ … }

/*
 * helper function to update the accounting in the head ref
 * existing and update must have the same bytenr
 */
static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans,
			 struct btrfs_delayed_ref_head *existing,
			 struct btrfs_delayed_ref_head *update)
{ … }

static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
				  struct btrfs_ref *generic_ref,
				  struct btrfs_qgroup_extent_record *qrecord,
				  u64 reserved)
{ … }

/*
 * helper function to actually insert a head node into the rbtree.
 * this does all the dirty work in terms of maintaining the correct
 * overall modification count.
 */
static noinline struct btrfs_delayed_ref_head *
add_delayed_ref_head(struct btrfs_trans_handle *trans,
		     struct btrfs_delayed_ref_head *head_ref,
		     struct btrfs_qgroup_extent_record *qrecord,
		     int action, bool *qrecord_inserted_ret)
{ … }

/*
 * Initialize the structure which represents a modification to a an extent.
 *
 * @fs_info:    Internal to the mounted filesystem mount structure.
 *
 * @ref:	The structure which is going to be initialized.
 *
 * @bytenr:	The logical address of the extent for which a modification is
 *		going to be recorded.
 *
 * @num_bytes:  Size of the extent whose modification is being recorded.
 *
 * @ref_root:	The id of the root where this modification has originated, this
 *		can be either one of the well-known metadata trees or the
 *		subvolume id which references this extent.
 *
 * @action:	Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
 *		BTRFS_ADD_DELAYED_EXTENT
 *
 * @ref_type:	Holds the type of the extent which is being recorded, can be
 *		one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
 *		when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
 *		BTRFS_EXTENT_DATA_REF_KEY when recording data extent
 */
static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
				    struct btrfs_delayed_ref_node *ref,
				    struct btrfs_ref *generic_ref)
{ … }

void btrfs_init_tree_ref(struct btrfs_ref *generic_ref, int level, u64 mod_root,
			 bool skip_qgroup)
{ … }

void btrfs_init_data_ref(struct btrfs_ref *generic_ref, u64 ino, u64 offset,
			 u64 mod_root, bool skip_qgroup)
{ … }

static int add_delayed_ref(struct btrfs_trans_handle *trans,
			   struct btrfs_ref *generic_ref,
			   struct btrfs_delayed_extent_op *extent_op,
			   u64 reserved)
{ … }

/*
 * Add a delayed tree ref. This does all of the accounting required to make sure
 * the delayed ref is eventually processed before this transaction commits.
 */
int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
			       struct btrfs_ref *generic_ref,
			       struct btrfs_delayed_extent_op *extent_op)
{ … }

/*
 * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
 */
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, u8 level,
				struct btrfs_delayed_extent_op *extent_op)
{ … }

void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
{ … }

/*
 * This does a simple search for the head node for a given extent.  Returns the
 * head node if found, or NULL if not.
 */
struct btrfs_delayed_ref_head *
btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
{ … }

void __cold btrfs_delayed_ref_exit(void)
{ … }

int __init btrfs_delayed_ref_init(void)
{ … }
linux/fs/btrfs/delayed-ref.c
