static int rebalance_children(struct shadow_spine *s,
struct dm_btree_info *info,
struct dm_btree_value_type *vt, uint64_t key)
{
int i, r, has_left_sibling, has_right_sibling;
uint32_t child_entries;
struct btree_node *n;
n = dm_block_data(shadow_current(s));
if (le32_to_cpu(n->header.nr_entries) == 1) {
struct dm_block *child;
dm_block_t b = value64(n, 0);
r = dm_tm_read_lock(info->tm, b, &btree_node_validator, &child);
if (r)
return r;
memcpy(n, dm_block_data(child),
dm_bm_block_size(dm_tm_get_bm(info->tm)));
r = dm_tm_unlock(info->tm, child);
if (r)
return r;
dm_tm_dec(info->tm, dm_block_location(child));
return 0;
}
i = lower_bound(n, key);
if (i < 0)
return -ENODATA;
r = get_nr_entries(info->tm, value64(n, i), &child_entries);
if (r)
return r;
has_left_sibling = i > 0;
has_right_sibling = i < (le32_to_cpu(n->header.nr_entries) - 1);
if (!has_left_sibling)
r = rebalance2(s, info, vt, i);
else if (!has_right_sibling)
r = rebalance2(s, info, vt, i - 1);
else
r = rebalance3(s, info, vt, i - 1);
return r;
}
/*
* Prepares for removal from one level of the hierarchy. The caller must
* call delete_at() to remove the entry at index.
*/
static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
struct dm_btree_value_type *vt, dm_block_t root,
uint64_t key, unsigned *index)
{
int i = *index, r;
struct btree_node *n;
for (;;) {
r = shadow_step(s, root, vt);
if (r < 0)
break;
/*
* We have to patch up the parent node, ugly, but I don't
* see a way to do this automatically as part of the spine
* op.
*/
if (shadow_has_parent(s)) {
__le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
memcpy(value_ptr(dm_block_data(shadow_parent(s)), i),
&location, sizeof(__le64));
}
n = dm_block_data(shadow_current(s));
if (le32_to_cpu(n->header.flags) & LEAF_NODE)
return do_leaf(n, key, index);
r = rebalance_children(s, info, vt, key);
if (r)
break;
n = dm_block_data(shadow_current(s));
if (le32_to_cpu(n->header.flags) & LEAF_NODE)
return do_leaf(n, key, index);
i = lower_bound(n, key);
/*
* We know the key is present, or else
* rebalance_children would have returned
* -ENODATA
*/
root = value64(n, i);
}
return r;
}
static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info,
struct dm_btree_value_type *vt, unsigned left_index)
{
int r;
struct btree_node *parent;
struct child left, right;
parent = dm_block_data(shadow_current(s));
r = init_child(info, vt, parent, left_index, &left);
if (r)
return r;
r = init_child(info, vt, parent, left_index + 1, &right);
if (r) {
exit_child(info, &left);
return r;
}
__rebalance2(info, parent, &left, &right);
r = exit_child(info, &left);
if (r) {
exit_child(info, &right);
return r;
}
return exit_child(info, &right);
}
static int init_child(struct dm_btree_info *info, struct dm_btree_value_type *vt,
struct btree_node *parent,
unsigned index, struct child *result)
{
int r, inc;
dm_block_t root;
result->index = index;
root = value64(parent, index);
r = dm_tm_shadow_block(info->tm, root, &btree_node_validator,
&result->block, &inc);
if (r)
return r;
result->n = dm_block_data(result->block);
if (inc)
inc_children(info->tm, result->n, vt);
*((__le64 *) value_ptr(parent, index)) =
cpu_to_le64(dm_block_location(result->block));
return 0;
}
int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
{
int r;
struct dm_block *b;
struct btree_node *n;
size_t block_size;
uint32_t max_entries;
r = new_block(info, &b);
if (r < 0)
return r;
block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
max_entries = calc_max_entries(info->value_type.size, block_size);
n = dm_block_data(b);
memset(n, 0, block_size);
n->header.flags = cpu_to_le32(LEAF_NODE);
n->header.nr_entries = cpu_to_le32(0);
n->header.max_entries = cpu_to_le32(max_entries);
n->header.value_size = cpu_to_le32(info->value_type.size);
*root = dm_block_location(b);
return unlock_block(info, b);
}
static int array_block_check(struct dm_block_validator *v,
struct dm_block *b,
size_t size_of_block)
{
struct array_block *bh_le = dm_block_data(b);
__le32 csum_disk;
if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
DMERR_LIMIT("array_block_check failed: blocknr %llu != wanted %llu",
(unsigned long long) le64_to_cpu(bh_le->blocknr),
(unsigned long long) dm_block_location(b));
return -ENOTBLK;
}
csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
size_of_block - sizeof(__le32),
CSUM_XOR));
if (csum_disk != bh_le->csum) {
DMERR_LIMIT("array_block_check failed: csum %u != wanted %u",
(unsigned) le32_to_cpu(csum_disk),
(unsigned) le32_to_cpu(bh_le->csum));
return -EILSEQ;
}
return 0;
}
/*
* FIXME: We shouldn't use a recursive algorithm when we have limited stack
* space. Also this only works for single level trees.
*/
static int walk_node(struct dm_btree_info *info, dm_block_t block,
int (*fn)(void *context, uint64_t *keys, void *leaf),
void *context)
{
int r;
unsigned i, nr;
struct dm_block *node;
struct btree_node *n;
uint64_t keys;
r = bn_read_lock(info, block, &node);
if (r)
return r;
n = dm_block_data(node);
nr = le32_to_cpu(n->header.nr_entries);
for (i = 0; i < nr; i++) {
if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) {
r = walk_node(info, value64(n, i), fn, context);
if (r)
goto out;
} else {
keys = le64_to_cpu(*key_ptr(n, i));
r = fn(context, &keys, value_ptr(n, i));
if (r)
goto out;
}
}
out:
dm_tm_unlock(info->tm, node);
return r;
}
static int sb_check(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct thin_disk_superblock *disk_super = dm_block_data(b);
__le32 csum_le;
if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
DMERR("sb_check failed: blocknr %llu: "
"wanted %llu", le64_to_cpu(disk_super->blocknr),
(unsigned long long)dm_block_location(b));
return -ENOTBLK;
}
if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
DMERR("sb_check failed: magic %llu: "
"wanted %llu", le64_to_cpu(disk_super->magic),
(unsigned long long)THIN_SUPERBLOCK_MAGIC);
return -EILSEQ;
}
csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR));
if (csum_le != disk_super->csum) {
DMERR("sb_check failed: csum %u: wanted %u",
le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
return -EILSEQ;
}
return 0;
}
struct 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);
}
static void array_block_prepare_for_write(struct dm_block_validator *v,
struct dm_block *b,
size_t size_of_block)
{
struct array_block *bh_le = dm_block_data(b);
bh_le->blocknr = cpu_to_le64(dm_block_location(b));
bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
size_of_block - sizeof(__le32),
CSUM_XOR));
}
static void sb_prepare_for_write(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct thin_disk_superblock *disk_super = dm_block_data(b);
disk_super->blocknr = cpu_to_le64(dm_block_location(b));
disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR));
}
/*
* Read locks a block, and coerces it to an array block. The caller must
* unlock 'block' when finished.
*/
static int get_ablock(struct dm_array_info *info, dm_block_t b,
struct dm_block **block, struct array_block **ab)
{
int r;
r = dm_tm_read_lock(info->btree_info.tm, b, &array_validator, block);
if (r)
return r;
*ab = dm_block_data(*block);
return 0;
}
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;
}
static void node_prepare_for_write(struct dm_block_validator *v,
struct dm_block *b,
size_t block_size)
{
struct 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 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;
}
/*
* Looks up an array block in the btree. Then shadows it, and updates the
* btree to point to this new shadow. 'root' is an input/output parameter
* for both the current root block, and the new one.
*/
static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
unsigned index, struct dm_block **block,
struct array_block **ab)
{
int r, inc;
uint64_t key = index;
dm_block_t b;
__le64 block_le;
/*
* lookup
*/
r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
if (r)
return r;
b = le64_to_cpu(block_le);
/*
* shadow
*/
r = dm_tm_shadow_block(info->btree_info.tm, b,
&array_validator, block, &inc);
if (r)
return r;
*ab = dm_block_data(*block);
if (inc)
inc_ablock_entries(info, *ab);
/*
* Reinsert.
*
* The shadow op will often be a noop. Only insert if it really
* copied data.
*/
if (dm_block_location(*block) != b) {
/*
* dm_tm_shadow_block will have already decremented the old
* block, but it is still referenced by the btree. We
* increment to stop the insert decrementing it below zero
* when overwriting the old value.
*/
dm_tm_inc(info->btree_info.tm, b);
r = insert_ablock(info, index, *block, root);
}
return r;
}
static int rebalance3(struct shadow_spine *s, struct dm_btree_info *info,
struct dm_btree_value_type *vt, unsigned left_index)
{
int r;
struct btree_node *parent = dm_block_data(shadow_current(s));
struct child left, center, right;
/*
* FIXME: fill out an array?
*/
r = init_child(info, vt, parent, left_index, &left);
if (r)
return r;
r = init_child(info, vt, parent, left_index + 1, ¢er);
if (r) {
exit_child(info, &left);
return r;
}
r = init_child(info, vt, parent, left_index + 2, &right);
if (r) {
exit_child(info, &left);
exit_child(info, ¢er);
return r;
}
__rebalance3(info, parent, &left, ¢er, &right);
r = exit_child(info, &left);
if (r) {
exit_child(info, ¢er);
exit_child(info, &right);
return r;
}
r = exit_child(info, ¢er);
if (r) {
exit_child(info, &right);
return r;
}
r = exit_child(info, &right);
if (r)
return r;
return 0;
}
static int get_nr_entries(struct dm_transaction_manager *tm,
dm_block_t b, uint32_t *result)
{
int r;
struct dm_block *block;
struct btree_node *n;
r = dm_tm_read_lock(tm, b, &btree_node_validator, &block);
if (r)
return r;
n = dm_block_data(block);
*result = le32_to_cpu(n->header.nr_entries);
return dm_tm_unlock(tm, block);
}
/*
* Allocate a new array block. The caller will need to unlock block.
*/
static int alloc_ablock(struct dm_array_info *info, size_t size_of_block,
uint32_t max_entries,
struct dm_block **block, struct array_block **ab)
{
int r;
r = dm_tm_new_block(info->btree_info.tm, &array_validator, block);
if (r)
return r;
(*ab) = dm_block_data(*block);
(*ab)->max_entries = cpu_to_le32(max_entries);
(*ab)->nr_entries = cpu_to_le32(0);
(*ab)->value_size = cpu_to_le32(info->value_type.size);
return 0;
}
static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
{
int r;
uint32_t ref_count;
if (s->top >= MAX_SPINE_DEPTH - 1) {
DMERR("btree deletion stack out of memory");
return -ENOMEM;
}
r = dm_tm_ref(s->tm, b, &ref_count);
if (r)
return r;
if (ref_count > 1)
/*
* This is a shared node, so we can just decrement it's
* reference counter and leave the children.
*/
dm_tm_dec(s->tm, b);
else {
uint32_t flags;
struct frame *f = s->spine + ++s->top;
r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
if (r) {
s->top--;
return r;
}
f->n = dm_block_data(f->b);
f->level = level;
f->nr_children = le32_to_cpu(f->n->header.nr_entries);
f->current_child = 0;
flags = le32_to_cpu(f->n->header.flags);
if (flags & INTERNAL_NODE || is_internal_level(s->info, f))
prefetch_children(s, f);
}
return 0;
}
/*
* Looks up an array block in the btree. Then shadows it, and updates the
* btree to point to this new shadow. 'root' is an input/output parameter
* for both the current root block, and the new one.
*/
static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
unsigned index, struct dm_block **block,
struct array_block **ab)
{
int r, inc;
uint64_t key = index;
dm_block_t b;
__le64 block_le;
/*
* lookup
*/
r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
if (r)
return r;
b = le64_to_cpu(block_le);
/*
* shadow
*/
r = dm_tm_shadow_block(info->btree_info.tm, b,
&array_validator, block, &inc);
if (r)
return r;
*ab = dm_block_data(*block);
if (inc)
inc_ablock_entries(info, *ab);
/*
* Reinsert.
*
* The shadow op will often be a noop. Only insert if it really
* copied data.
*/
if (dm_block_location(*block) != b)
r = insert_ablock(info, index, *block, root);
return r;
}
int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
uint64_t *keys, dm_block_t *new_root)
{
unsigned level, last_level = info->levels - 1;
int index = 0, r = 0;
struct shadow_spine spine;
struct btree_node *n;
struct dm_btree_value_type le64_vt;
init_le64_type(info->tm, &le64_vt);
init_shadow_spine(&spine, info);
for (level = 0; level < info->levels; level++) {
r = remove_raw(&spine, info,
(level == last_level ?
&info->value_type : &le64_vt),
root, keys[level], (unsigned *)&index);
if (r < 0)
break;
n = dm_block_data(shadow_current(&spine));
if (level != last_level) {
root = value64(n, index);
continue;
}
BUG_ON(index < 0 || index >= le32_to_cpu(n->header.nr_entries));
if (info->value_type.dec)
info->value_type.dec(info->value_type.context,
value_ptr(n, index));
delete_at(n, index);
}
*new_root = shadow_root(&spine);
exit_shadow_spine(&spine);
return r;
}
static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
struct dm_btree_value_type *vt,
uint64_t key, unsigned *index)
{
int r, i = *index, top = 1;
struct btree_node *node;
for (;;) {
r = shadow_step(s, root, vt);
if (r < 0)
return r;
node = dm_block_data(shadow_current(s));
/*
* We have to patch up the parent node, ugly, but I don't
* see a way to do this automatically as part of the spine
* op.
*/
if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */
__le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
__dm_bless_for_disk(&location);
memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i),
&location, sizeof(__le64));
}
node = dm_block_data(shadow_current(s));
if (node->header.nr_entries == node->header.max_entries) {
if (top)
r = btree_split_beneath(s, key);
else
r = btree_split_sibling(s, root, i, key);
if (r < 0)
return r;
}
node = dm_block_data(shadow_current(s));
i = lower_bound(node, key);
if (le32_to_cpu(node->header.flags) & LEAF_NODE)
break;
if (i < 0) {
/* change the bounds on the lowest key */
node->keys[0] = cpu_to_le64(key);
i = 0;
}
root = value64(node, i);
top = 0;
}
if (i < 0 || le64_to_cpu(node->keys[i]) != key)
i++;
*index = i;
return 0;
}
/*
* Splits a node by creating a sibling node and shifting half the nodes
* contents across. Assumes there is a parent node, and it has room for
* another child.
*
* Before:
* +--------+
* | Parent |
* +--------+
* |
* v
* +----------+
* | A ++++++ |
* +----------+
*
*
* After:
* +--------+
* | Parent |
* +--------+
* | |
* v +------+
* +---------+ |
* | A* +++ | v
* +---------+ +-------+
* | B +++ |
* +-------+
*
* Where A* is a shadow of A.
*/
static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,
unsigned parent_index, uint64_t key)
{
int r;
size_t size;
unsigned nr_left, nr_right;
struct dm_block *left, *right, *parent;
struct btree_node *ln, *rn, *pn;
__le64 location;
left = shadow_current(s);
r = new_block(s->info, &right);
if (r < 0)
return r;
ln = dm_block_data(left);
rn = dm_block_data(right);
nr_left = le32_to_cpu(ln->header.nr_entries) / 2;
nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left;
ln->header.nr_entries = cpu_to_le32(nr_left);
rn->header.flags = ln->header.flags;
rn->header.nr_entries = cpu_to_le32(nr_right);
rn->header.max_entries = ln->header.max_entries;
rn->header.value_size = ln->header.value_size;
memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0]));
size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ?
sizeof(uint64_t) : s->info->value_type.size;
memcpy(value_ptr(rn, 0), value_ptr(ln, nr_left),
size * nr_right);
/*
* Patch up the parent
*/
parent = shadow_parent(s);
pn = dm_block_data(parent);
location = cpu_to_le64(dm_block_location(left));
__dm_bless_for_disk(&location);
memcpy_disk(value_ptr(pn, parent_index),
&location, sizeof(__le64));
location = cpu_to_le64(dm_block_location(right));
__dm_bless_for_disk(&location);
r = insert_at(sizeof(__le64), pn, parent_index + 1,
le64_to_cpu(rn->keys[0]), &location);
if (r)
return r;
if (key < le64_to_cpu(rn->keys[0])) {
unlock_block(s->info, right);
s->nodes[1] = left;
} else {
unlock_block(s->info, left);
s->nodes[1] = right;
}
return 0;
}
/*
* Splits a node by creating two new children beneath the given node.
*
* Before:
* +----------+
* | A ++++++ |
* +----------+
*
*
* After:
* +------------+
* | A (shadow) |
* +------------+
* | |
* +------+ +----+
* | |
* v v
* +-------+ +-------+
* | B +++ | | C +++ |
* +-------+ +-------+
*/
static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
{
int r;
size_t size;
unsigned nr_left, nr_right;
struct dm_block *left, *right, *new_parent;
struct btree_node *pn, *ln, *rn;
__le64 val;
new_parent = shadow_current(s);
r = new_block(s->info, &left);
if (r < 0)
return r;
r = new_block(s->info, &right);
if (r < 0) {
/* FIXME: put left */
return r;
}
pn = dm_block_data(new_parent);
ln = dm_block_data(left);
rn = dm_block_data(right);
nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
ln->header.flags = pn->header.flags;
ln->header.nr_entries = cpu_to_le32(nr_left);
ln->header.max_entries = pn->header.max_entries;
ln->header.value_size = pn->header.value_size;
rn->header.flags = pn->header.flags;
rn->header.nr_entries = cpu_to_le32(nr_right);
rn->header.max_entries = pn->header.max_entries;
rn->header.value_size = pn->header.value_size;
memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
sizeof(__le64) : s->info->value_type.size;
memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size);
memcpy(value_ptr(rn, 0), value_ptr(pn, nr_left),
nr_right * size);
/* new_parent should just point to l and r now */
pn->header.flags = cpu_to_le32(INTERNAL_NODE);
pn->header.nr_entries = cpu_to_le32(2);
pn->header.max_entries = cpu_to_le32(
calc_max_entries(sizeof(__le64),
dm_bm_block_size(
dm_tm_get_bm(s->info->tm))));
pn->header.value_size = cpu_to_le32(sizeof(__le64));
val = cpu_to_le64(dm_block_location(left));
__dm_bless_for_disk(&val);
pn->keys[0] = ln->keys[0];
memcpy_disk(value_ptr(pn, 0), &val, sizeof(__le64));
val = cpu_to_le64(dm_block_location(right));
__dm_bless_for_disk(&val);
pn->keys[1] = rn->keys[0];
memcpy_disk(value_ptr(pn, 1), &val, sizeof(__le64));
/*
* rejig the spine. This is ugly, since it knows too
* much about the spine
*/
if (s->nodes[0] != new_parent) {
unlock_block(s->info, s->nodes[0]);
s->nodes[0] = new_parent;
}
if (key < le64_to_cpu(rn->keys[0])) {
unlock_block(s->info, right);
s->nodes[1] = left;
} else {
unlock_block(s->info, left);
s->nodes[1] = right;
}
s->count = 2;
return 0;
}
