![Joe Thornber](/assets/img/avatar_default.png)
Add dm_btree_walk to iterate through the contents of a btree. This will be used by the dm cache target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
252 lines
5.1 KiB
C
252 lines
5.1 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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#include "dm-btree-internal.h"
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#include "dm-transaction-manager.h"
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#include <linux/device-mapper.h>
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#define DM_MSG_PREFIX "btree spine"
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/*----------------------------------------------------------------*/
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#define BTREE_CSUM_XOR 121107
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static int node_check(struct dm_block_validator *v,
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struct dm_block *b,
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size_t block_size);
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static void node_prepare_for_write(struct dm_block_validator *v,
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struct dm_block *b,
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size_t block_size)
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{
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struct btree_node *n = dm_block_data(b);
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struct node_header *h = &n->header;
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h->blocknr = cpu_to_le64(dm_block_location(b));
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h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
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block_size - sizeof(__le32),
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BTREE_CSUM_XOR));
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BUG_ON(node_check(v, b, 4096));
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}
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static int node_check(struct dm_block_validator *v,
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struct dm_block *b,
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size_t block_size)
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{
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struct btree_node *n = dm_block_data(b);
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struct node_header *h = &n->header;
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size_t value_size;
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__le32 csum_disk;
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uint32_t flags;
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if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
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DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
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le64_to_cpu(h->blocknr), dm_block_location(b));
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return -ENOTBLK;
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}
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csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
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block_size - sizeof(__le32),
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BTREE_CSUM_XOR));
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if (csum_disk != h->csum) {
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DMERR_LIMIT("node_check failed: csum %u != wanted %u",
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le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
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return -EILSEQ;
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}
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value_size = le32_to_cpu(h->value_size);
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if (sizeof(struct node_header) +
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(sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) {
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DMERR_LIMIT("node_check failed: max_entries too large");
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return -EILSEQ;
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}
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if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) {
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DMERR_LIMIT("node_check failed: too many entries");
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return -EILSEQ;
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}
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/*
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* The node must be either INTERNAL or LEAF.
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*/
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flags = le32_to_cpu(h->flags);
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if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
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DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
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return -EILSEQ;
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}
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return 0;
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}
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struct dm_block_validator btree_node_validator = {
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.name = "btree_node",
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.prepare_for_write = node_prepare_for_write,
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.check = node_check
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};
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/*----------------------------------------------------------------*/
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static 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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{
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return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
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}
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static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
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struct dm_btree_value_type *vt,
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struct dm_block **result)
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{
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int r, inc;
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r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
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result, &inc);
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if (!r && inc)
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inc_children(info->tm, dm_block_data(*result), vt);
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return r;
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}
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int new_block(struct dm_btree_info *info, struct dm_block **result)
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{
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return dm_tm_new_block(info->tm, &btree_node_validator, result);
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}
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int unlock_block(struct dm_btree_info *info, struct dm_block *b)
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{
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return dm_tm_unlock(info->tm, b);
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}
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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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{
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s->info = info;
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s->count = 0;
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s->nodes[0] = NULL;
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s->nodes[1] = NULL;
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}
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int exit_ro_spine(struct ro_spine *s)
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{
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int r = 0, i;
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for (i = 0; i < s->count; i++) {
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int r2 = unlock_block(s->info, s->nodes[i]);
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if (r2 < 0)
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r = r2;
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}
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return r;
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}
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int ro_step(struct ro_spine *s, dm_block_t new_child)
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{
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int r;
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if (s->count == 2) {
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r = unlock_block(s->info, s->nodes[0]);
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if (r < 0)
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return r;
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s->nodes[0] = s->nodes[1];
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s->count--;
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}
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r = bn_read_lock(s->info, new_child, s->nodes + s->count);
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if (!r)
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s->count++;
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return r;
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}
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void ro_pop(struct ro_spine *s)
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{
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BUG_ON(!s->count);
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--s->count;
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unlock_block(s->info, s->nodes[s->count]);
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}
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struct btree_node *ro_node(struct ro_spine *s)
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{
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struct dm_block *block;
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BUG_ON(!s->count);
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block = s->nodes[s->count - 1];
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return dm_block_data(block);
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}
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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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{
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s->info = info;
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s->count = 0;
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}
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int exit_shadow_spine(struct shadow_spine *s)
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{
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int r = 0, i;
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for (i = 0; i < s->count; i++) {
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int r2 = unlock_block(s->info, s->nodes[i]);
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if (r2 < 0)
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r = r2;
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}
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return r;
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}
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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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int r;
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if (s->count == 2) {
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r = unlock_block(s->info, s->nodes[0]);
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if (r < 0)
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return r;
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s->nodes[0] = s->nodes[1];
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s->count--;
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}
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r = bn_shadow(s->info, b, vt, s->nodes + s->count);
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if (!r) {
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if (!s->count)
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s->root = dm_block_location(s->nodes[0]);
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s->count++;
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}
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return r;
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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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BUG_ON(!s->count);
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return s->nodes[s->count - 1];
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}
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struct dm_block *shadow_parent(struct shadow_spine *s)
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{
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BUG_ON(s->count != 2);
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return s->count == 2 ? s->nodes[0] : NULL;
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}
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int shadow_has_parent(struct shadow_spine *s)
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{
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return s->count >= 2;
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}
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int shadow_root(struct shadow_spine *s)
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{
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return s->root;
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}
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