be500ed721
When we break sharing on btree nodes we typically need to increment the reference counts to every value held in the node. This can cause a lot of repeated calls to the space maps. Fix this by changing the interface to the space map inc/dec methods to take ranges of adjacent blocks to be operated on. For installations that are using a lot of snapshots this will reduce cpu overhead of fundamental operations such as provisioning a new block, or deleting a snapshot, by as much as 10 times. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
161 lines
4.0 KiB
C
161 lines
4.0 KiB
C
/*
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* Copyright (C) 2011 Red Hat, Inc.
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*
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* This file is released under the GPL.
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*/
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#ifndef DM_BTREE_INTERNAL_H
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#define DM_BTREE_INTERNAL_H
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#include "dm-btree.h"
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/*----------------------------------------------------------------*/
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/*
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* We'll need 2 accessor functions for n->csum and n->blocknr
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* to support dm-btree-spine.c in that case.
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*/
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enum node_flags {
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INTERNAL_NODE = 1,
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LEAF_NODE = 1 << 1
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};
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/*
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* Every btree node begins with this structure. Make sure it's a multiple
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* of 8-bytes in size, otherwise the 64bit keys will be mis-aligned.
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*/
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struct node_header {
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__le32 csum;
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__le32 flags;
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__le64 blocknr; /* Block this node is supposed to live in. */
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__le32 nr_entries;
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__le32 max_entries;
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__le32 value_size;
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__le32 padding;
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} __attribute__((packed, aligned(8)));
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struct btree_node {
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struct node_header header;
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__le64 keys[];
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} __attribute__((packed, aligned(8)));
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/*
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* Locks a block using the btree node validator.
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*/
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int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
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struct dm_block **result);
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void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
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struct dm_btree_value_type *vt);
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int new_block(struct dm_btree_info *info, struct dm_block **result);
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void unlock_block(struct dm_btree_info *info, struct dm_block *b);
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/*
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* Spines keep track of the rolling locks. There are 2 variants, read-only
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* and one that uses shadowing. These are separate structs to allow the
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* type checker to spot misuse, for example accidentally calling read_lock
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* on a shadow spine.
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*/
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struct ro_spine {
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struct dm_btree_info *info;
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int count;
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struct dm_block *nodes[2];
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};
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void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
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void exit_ro_spine(struct ro_spine *s);
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int ro_step(struct ro_spine *s, dm_block_t new_child);
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void ro_pop(struct ro_spine *s);
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struct btree_node *ro_node(struct ro_spine *s);
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struct shadow_spine {
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struct dm_btree_info *info;
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int count;
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struct dm_block *nodes[2];
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dm_block_t root;
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};
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void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info);
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void exit_shadow_spine(struct shadow_spine *s);
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int shadow_step(struct shadow_spine *s, dm_block_t b,
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struct dm_btree_value_type *vt);
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/*
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* The spine must have at least one entry before calling this.
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*/
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struct dm_block *shadow_current(struct shadow_spine *s);
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/*
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* The spine must have at least two entries before calling this.
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*/
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struct dm_block *shadow_parent(struct shadow_spine *s);
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int shadow_has_parent(struct shadow_spine *s);
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dm_block_t shadow_root(struct shadow_spine *s);
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/*
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* Some inlines.
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*/
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static inline __le64 *key_ptr(struct btree_node *n, uint32_t index)
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{
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return n->keys + index;
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}
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static inline void *value_base(struct btree_node *n)
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{
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return &n->keys[le32_to_cpu(n->header.max_entries)];
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}
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static inline void *value_ptr(struct btree_node *n, uint32_t index)
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{
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uint32_t value_size = le32_to_cpu(n->header.value_size);
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return value_base(n) + (value_size * index);
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}
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/*
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* Assumes the values are suitably-aligned and converts to core format.
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*/
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static inline uint64_t value64(struct btree_node *n, uint32_t index)
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{
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__le64 *values_le = value_base(n);
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return le64_to_cpu(values_le[index]);
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}
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/*
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* Searching for a key within a single node.
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*/
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int lower_bound(struct btree_node *n, uint64_t key);
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extern struct dm_block_validator btree_node_validator;
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/*
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* Value type for upper levels of multi-level btrees.
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*/
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extern void init_le64_type(struct dm_transaction_manager *tm,
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struct dm_btree_value_type *vt);
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/*
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* This returns a shadowed btree leaf that you may modify. In practise
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* this means overwrites only, since an insert could cause a node to
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* be split. Useful if you need access to the old value to calculate the
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* new one.
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*
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* This only works with single level btrees. The given key must be present in
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* the tree, otherwise -EINVAL will be returned.
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*/
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int btree_get_overwrite_leaf(struct dm_btree_info *info, dm_block_t root,
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uint64_t key, int *index,
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dm_block_t *new_root, struct dm_block **leaf);
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#endif /* DM_BTREE_INTERNAL_H */
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