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/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#include "dm-btree-internal.h"
#include "dm-transaction-manager.h"
#include <linux/device-mapper.h>
#define DM_MSG_PREFIX "btree spine"
/*----------------------------------------------------------------*/
#define BTREE_CSUM_XOR 121107
static int node_check(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size);
static void node_prepare_for_write(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct btree_node *n = dm_block_data(b);
struct node_header *h = &n->header;
h->blocknr = cpu_to_le64(dm_block_location(b));
h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
block_size - sizeof(__le32),
BTREE_CSUM_XOR));
BUG_ON(node_check(v, b, 4096));
}
static int node_check(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct btree_node *n = dm_block_data(b);
struct node_header *h = &n->header;
size_t value_size;
__le32 csum_disk;
uint32_t flags;
if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
le64_to_cpu(h->blocknr), dm_block_location(b));
return -ENOTBLK;
}
csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
block_size - sizeof(__le32),
BTREE_CSUM_XOR));
if (csum_disk != h->csum) {
DMERR_LIMIT("node_check failed: csum %u != wanted %u",
le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
return -EILSEQ;
}
value_size = le32_to_cpu(h->value_size);
if (sizeof(struct node_header) +
(sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) {
DMERR_LIMIT("node_check failed: max_entries too large");
return -EILSEQ;
}
if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) {
DMERR_LIMIT("node_check failed: too many entries");
return -EILSEQ;
}
/*
* The node must be either INTERNAL or LEAF.
*/
flags = le32_to_cpu(h->flags);
if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
return -EILSEQ;
}
return 0;
}
struct dm_block_validator btree_node_validator = {
.name = "btree_node",
.prepare_for_write = node_prepare_for_write,
.check = node_check
};
/*----------------------------------------------------------------*/
static int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
struct dm_block **result)
{
return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
}
static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
struct dm_btree_value_type *vt,
struct dm_block **result)
{
int r, inc;
r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
result, &inc);
if (!r && inc)
inc_children(info->tm, dm_block_data(*result), vt);
return r;
}
int new_block(struct dm_btree_info *info, struct dm_block **result)
{
return dm_tm_new_block(info->tm, &btree_node_validator, result);
}
int unlock_block(struct dm_btree_info *info, struct dm_block *b)
{
return dm_tm_unlock(info->tm, b);
}
/*----------------------------------------------------------------*/
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
{
s->info = info;
s->count = 0;
s->nodes[0] = NULL;
s->nodes[1] = NULL;
}
int exit_ro_spine(struct ro_spine *s)
{
int r = 0, i;
for (i = 0; i < s->count; i++) {
int r2 = unlock_block(s->info, s->nodes[i]);
if (r2 < 0)
r = r2;
}
return r;
}
int ro_step(struct ro_spine *s, dm_block_t new_child)
{
int r;
if (s->count == 2) {
r = unlock_block(s->info, s->nodes[0]);
if (r < 0)
return r;
s->nodes[0] = s->nodes[1];
s->count--;
}
r = bn_read_lock(s->info, new_child, s->nodes + s->count);
if (!r)
s->count++;
return r;
}
struct btree_node *ro_node(struct ro_spine *s)
{
struct dm_block *block;
BUG_ON(!s->count);
block = s->nodes[s->count - 1];
return dm_block_data(block);
}
/*----------------------------------------------------------------*/
void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
{
s->info = info;
s->count = 0;
}
int exit_shadow_spine(struct shadow_spine *s)
{
int r = 0, i;
for (i = 0; i < s->count; i++) {
int r2 = unlock_block(s->info, s->nodes[i]);
if (r2 < 0)
r = r2;
}
return r;
}
int shadow_step(struct shadow_spine *s, dm_block_t b,
struct dm_btree_value_type *vt)
{
int r;
if (s->count == 2) {
r = unlock_block(s->info, s->nodes[0]);
if (r < 0)
return r;
s->nodes[0] = s->nodes[1];
s->count--;
}
r = bn_shadow(s->info, b, vt, s->nodes + s->count);
if (!r) {
if (!s->count)
s->root = dm_block_location(s->nodes[0]);
s->count++;
}
return r;
}
struct dm_block *shadow_current(struct shadow_spine *s)
{
BUG_ON(!s->count);
return s->nodes[s->count - 1];
}
struct dm_block *shadow_parent(struct shadow_spine *s)
{
BUG_ON(s->count != 2);
return s->count == 2 ? s->nodes[0] : NULL;
}
int shadow_has_parent(struct shadow_spine *s)
{
return s->count >= 2;
}
int shadow_root(struct shadow_spine *s)
{
return s->root;
}
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