3241b1d3e0
The persistent-data library offers a re-usable framework for the storage and management of on-disk metadata in device-mapper targets. It's used by the thin-provisioning target in the next patch and in an upcoming hierarchical storage target. For further information, please read Documentation/device-mapper/persistent-data.txt Signed-off-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
137 lines
3.1 KiB
C
137 lines
3.1 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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} __packed;
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struct node {
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struct node_header header;
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__le64 keys[0];
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} __packed;
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void inc_children(struct dm_transaction_manager *tm, struct 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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int 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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int 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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struct 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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int 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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int 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 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 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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/*
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* FIXME: Now that value size is stored in node we don't need the third parm.
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*/
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static inline void *value_ptr(struct node *n, uint32_t index, size_t value_size)
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{
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BUG_ON(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 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 node *n, uint64_t key);
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extern struct dm_block_validator btree_node_validator;
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#endif /* DM_BTREE_INTERNAL_H */
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