289 lines
8.3 KiB
C
289 lines
8.3 KiB
C
/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __DELAYED_REF__
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#define __DELAYED_REF__
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/* these are the possible values of struct btrfs_delayed_ref_node->action */
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#define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */
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#define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */
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#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
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#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */
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struct btrfs_delayed_ref_node {
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struct rb_node rb_node;
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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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atomic_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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/* is this node still in the rbtree? */
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unsigned int is_head:1;
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unsigned int in_tree:1;
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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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u64 flags_to_set;
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int level;
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unsigned int update_key:1;
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unsigned int update_flags:1;
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unsigned int is_data:1;
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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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struct btrfs_delayed_ref_node 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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struct list_head cluster;
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struct btrfs_delayed_extent_op *extent_op;
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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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unsigned int must_insert_reserved:1;
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unsigned int is_data:1;
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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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struct btrfs_delayed_ref_root {
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struct rb_root 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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unsigned long 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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/*
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* bumped when someone is making progress on the delayed
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* refs, so that other procs know they are just adding to
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* contention intead of helping
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*/
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atomic_t procs_running_refs;
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atomic_t ref_seq;
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wait_queue_head_t wait;
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/*
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* set when the tree is flushing before a transaction commit,
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* used by the throttling code to decide if new updates need
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* to be run right away
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*/
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int flushing;
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u64 run_delayed_start;
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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 btrfs_delayed_ref_init(void);
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void btrfs_delayed_ref_exit(void);
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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(atomic_read(&ref->refs) == 0);
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if (atomic_dec_and_test(&ref->refs)) {
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WARN_ON(ref->in_tree);
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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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case 0:
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kmem_cache_free(btrfs_delayed_ref_head_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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int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
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struct btrfs_trans_handle *trans,
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u64 bytenr, u64 num_bytes, u64 parent,
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u64 ref_root, int level, int action,
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struct btrfs_delayed_extent_op *extent_op,
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int for_cow);
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int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
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struct btrfs_trans_handle *trans,
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u64 bytenr, u64 num_bytes,
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u64 parent, u64 ref_root,
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u64 owner, u64 offset, int action,
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struct btrfs_delayed_extent_op *extent_op,
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int for_cow);
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int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
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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_trans_handle *trans,
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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_trans_handle *trans, u64 bytenr);
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int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
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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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int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
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struct list_head *cluster, u64 search_start);
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void btrfs_release_ref_cluster(struct list_head *cluster);
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int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
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struct btrfs_delayed_ref_root *delayed_refs,
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u64 seq);
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/*
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* delayed refs with a ref_seq > 0 must be held back during backref walking.
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* this only applies to items in one of the fs-trees. for_cow items never need
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* to be held back, so they won't get a ref_seq number.
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*/
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static inline int need_ref_seq(int for_cow, u64 rootid)
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{
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if (for_cow)
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return 0;
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if (rootid == BTRFS_FS_TREE_OBJECTID)
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return 1;
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if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
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return 1;
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return 0;
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}
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/*
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* a node might live in a head or a regular ref, this lets you
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* test for the proper type to use.
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*/
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static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
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{
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return node->is_head;
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}
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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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WARN_ON(btrfs_delayed_ref_is_head(node));
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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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WARN_ON(btrfs_delayed_ref_is_head(node));
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return container_of(node, struct btrfs_delayed_data_ref, node);
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}
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static inline struct btrfs_delayed_ref_head *
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btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
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{
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WARN_ON(!btrfs_delayed_ref_is_head(node));
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return container_of(node, struct btrfs_delayed_ref_head, node);
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}
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#endif
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