/* SPDX-License-Identifier: GPL-2.0 */ /* * Copyright (C) 2008 Oracle. All rights reserved. */ #ifndef BTRFS_DELAYED_REF_H #define BTRFS_DELAYED_REF_H #include <linux/refcount.h> /* these are the possible values of struct btrfs_delayed_ref_node->action */ #define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */ #define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */ #define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */ #define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ 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; refcount_t refs; /* * the mutex is held while running the refs, and it is also * held when checking the sum of reference modifications. */ struct mutex mutex; 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 rb_node href_node; 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; /* * For qgroup reserved space freeing. * * ref_root and reserved will be recorded after * BTRFS_ADD_DELAYED_EXTENT is called. * And will be used to free reserved qgroup space at * run_delayed_refs() time. */ u64 qgroup_ref_root; u64 qgroup_reserved; /* * 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. */ unsigned int must_insert_reserved:1; unsigned int is_data:1; unsigned int is_system:1; unsigned int processing:1; }; 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; }; 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; /* * set when the tree is flushing before a transaction commit, * used by the throttling code to decide if new updates need * to be run right away */ int flushing; 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; }; 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 struct btrfs_delayed_extent_op * btrfs_alloc_delayed_extent_op(void) { return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS); } 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 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_fs_info *fs_info, struct btrfs_trans_handle *trans, u64 bytenr, u64 num_bytes, u64 parent, u64 ref_root, u64 owner, u64 offset, u64 reserved, int action, int *old_ref_mod, int *new_ref_mod); int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, 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_trans_handle *trans, struct btrfs_delayed_ref_head *head); static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) { mutex_unlock(&head->mutex); } 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); /* * 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); } #endif