| /* |
| * 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 __DELAYED_REF__ |
| #define __DELAYED_REF__ |
| |
| /* these are the possible values of struct btrfs_delayed_ref->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 */ |
| |
| struct btrfs_delayed_ref_node { |
| struct rb_node rb_node; |
| |
| /* the starting bytenr of the extent */ |
| u64 bytenr; |
| |
| /* the parent our backref will point to */ |
| u64 parent; |
| |
| /* the size of the extent */ |
| u64 num_bytes; |
| |
| /* ref count on this data structure */ |
| atomic_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; |
| |
| /* is this node still in the rbtree? */ |
| unsigned int in_tree:1; |
| }; |
| |
| /* |
| * 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 { |
| struct btrfs_delayed_ref_node node; |
| |
| /* |
| * the mutex is held while running the refs, and it is also |
| * held when checking the sum of reference modifications. |
| */ |
| struct mutex mutex; |
| |
| struct list_head cluster; |
| |
| /* |
| * 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; |
| }; |
| |
| struct btrfs_delayed_ref { |
| struct btrfs_delayed_ref_node node; |
| |
| /* the root objectid our ref will point to */ |
| u64 root; |
| |
| /* the generation for the backref */ |
| u64 generation; |
| |
| /* owner_objectid of the backref */ |
| u64 owner_objectid; |
| |
| /* operation done by this entry in the rbtree */ |
| u8 action; |
| |
| /* if pin == 1, when the extent is freed it will be pinned until |
| * transaction commit |
| */ |
| unsigned int pin:1; |
| }; |
| |
| struct btrfs_delayed_ref_root { |
| struct rb_root 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 |
| */ |
| unsigned long 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; |
| |
| /* |
| * 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; |
| }; |
| |
| static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) |
| { |
| WARN_ON(atomic_read(&ref->refs) == 0); |
| if (atomic_dec_and_test(&ref->refs)) { |
| WARN_ON(ref->in_tree); |
| kfree(ref); |
| } |
| } |
| |
| int btrfs_add_delayed_ref(struct btrfs_trans_handle *trans, |
| u64 bytenr, u64 num_bytes, u64 parent, u64 ref_root, |
| u64 ref_generation, u64 owner_objectid, int action, |
| int pin); |
| |
| struct btrfs_delayed_ref_head * |
| btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); |
| int btrfs_delayed_ref_pending(struct btrfs_trans_handle *trans, u64 bytenr); |
| int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, u64 bytenr, |
| u64 num_bytes, u32 *refs); |
| int btrfs_update_delayed_ref(struct btrfs_trans_handle *trans, |
| u64 bytenr, u64 num_bytes, u64 orig_parent, |
| u64 parent, u64 orig_ref_root, u64 ref_root, |
| u64 orig_ref_generation, u64 ref_generation, |
| u64 owner_objectid, int pin); |
| int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, |
| struct btrfs_delayed_ref_head *head); |
| int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, |
| struct list_head *cluster, u64 search_start); |
| /* |
| * a node might live in a head or a regular ref, this lets you |
| * test for the proper type to use. |
| */ |
| static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node) |
| { |
| return node->parent == (u64)-1; |
| } |
| |
| /* |
| * helper functions to cast a node into its container |
| */ |
| static inline struct btrfs_delayed_ref * |
| btrfs_delayed_node_to_ref(struct btrfs_delayed_ref_node *node) |
| { |
| WARN_ON(btrfs_delayed_ref_is_head(node)); |
| return container_of(node, struct btrfs_delayed_ref, node); |
| |
| } |
| |
| static inline struct btrfs_delayed_ref_head * |
| btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node) |
| { |
| WARN_ON(!btrfs_delayed_ref_is_head(node)); |
| return container_of(node, struct btrfs_delayed_ref_head, node); |
| |
| } |
| #endif |