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path: root/drivers/md/persistent-data/dm-btree-remove.c
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Diffstat (limited to 'drivers/md/persistent-data/dm-btree-remove.c')
-rw-r--r--drivers/md/persistent-data/dm-btree-remove.c284
1 files changed, 155 insertions, 129 deletions
diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c
index 023fbc2d389..b88757cd0d1 100644
--- a/drivers/md/persistent-data/dm-btree-remove.c
+++ b/drivers/md/persistent-data/dm-btree-remove.c
@@ -53,7 +53,7 @@
/*
* Some little utilities for moving node data around.
*/
-static void node_shift(struct node *n, int shift)
+static void node_shift(struct btree_node *n, int shift)
{
uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
uint32_t value_size = le32_to_cpu(n->header.value_size);
@@ -61,25 +61,25 @@ static void node_shift(struct node *n, int shift)
if (shift < 0) {
shift = -shift;
BUG_ON(shift > nr_entries);
- BUG_ON((void *) key_ptr(n, shift) >= value_ptr(n, shift, value_size));
+ BUG_ON((void *) key_ptr(n, shift) >= value_ptr(n, shift));
memmove(key_ptr(n, 0),
key_ptr(n, shift),
(nr_entries - shift) * sizeof(__le64));
- memmove(value_ptr(n, 0, value_size),
- value_ptr(n, shift, value_size),
+ memmove(value_ptr(n, 0),
+ value_ptr(n, shift),
(nr_entries - shift) * value_size);
} else {
BUG_ON(nr_entries + shift > le32_to_cpu(n->header.max_entries));
memmove(key_ptr(n, shift),
key_ptr(n, 0),
nr_entries * sizeof(__le64));
- memmove(value_ptr(n, shift, value_size),
- value_ptr(n, 0, value_size),
+ memmove(value_ptr(n, shift),
+ value_ptr(n, 0),
nr_entries * value_size);
}
}
-static void node_copy(struct node *left, struct node *right, int shift)
+static void node_copy(struct btree_node *left, struct btree_node *right, int shift)
{
uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
uint32_t value_size = le32_to_cpu(left->header.value_size);
@@ -91,16 +91,16 @@ static void node_copy(struct node *left, struct node *right, int shift)
memcpy(key_ptr(left, nr_left),
key_ptr(right, 0),
shift * sizeof(__le64));
- memcpy(value_ptr(left, nr_left, value_size),
- value_ptr(right, 0, value_size),
+ memcpy(value_ptr(left, nr_left),
+ value_ptr(right, 0),
shift * value_size);
} else {
BUG_ON(shift > le32_to_cpu(right->header.max_entries));
memcpy(key_ptr(right, 0),
key_ptr(left, nr_left - shift),
shift * sizeof(__le64));
- memcpy(value_ptr(right, 0, value_size),
- value_ptr(left, nr_left - shift, value_size),
+ memcpy(value_ptr(right, 0),
+ value_ptr(left, nr_left - shift),
shift * value_size);
}
}
@@ -108,7 +108,7 @@ static void node_copy(struct node *left, struct node *right, int shift)
/*
* Delete a specific entry from a leaf node.
*/
-static void delete_at(struct node *n, unsigned index)
+static void delete_at(struct btree_node *n, unsigned index)
{
unsigned nr_entries = le32_to_cpu(n->header.nr_entries);
unsigned nr_to_copy = nr_entries - (index + 1);
@@ -120,43 +120,27 @@ static void delete_at(struct node *n, unsigned index)
key_ptr(n, index + 1),
nr_to_copy * sizeof(__le64));
- memmove(value_ptr(n, index, value_size),
- value_ptr(n, index + 1, value_size),
+ memmove(value_ptr(n, index),
+ value_ptr(n, index + 1),
nr_to_copy * value_size);
}
n->header.nr_entries = cpu_to_le32(nr_entries - 1);
}
-static unsigned del_threshold(struct node *n)
+static unsigned merge_threshold(struct btree_node *n)
{
return le32_to_cpu(n->header.max_entries) / 3;
}
-static unsigned merge_threshold(struct node *n)
-{
- /*
- * The extra one is because we know we're potentially going to
- * delete an entry.
- */
- return 2 * (le32_to_cpu(n->header.max_entries) / 3) + 1;
-}
-
struct child {
unsigned index;
struct dm_block *block;
- struct node *n;
+ struct btree_node *n;
};
-static struct dm_btree_value_type le64_type = {
- .context = NULL,
- .size = sizeof(__le64),
- .inc = NULL,
- .dec = NULL,
- .equal = NULL
-};
-
-static int init_child(struct dm_btree_info *info, struct node *parent,
+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;
@@ -173,9 +157,9 @@ static int init_child(struct dm_btree_info *info, struct node *parent,
result->n = dm_block_data(result->block);
if (inc)
- inc_children(info->tm, result->n, &le64_type);
+ inc_children(info->tm, result->n, vt);
- *((__le64 *) value_ptr(parent, index, sizeof(__le64))) =
+ *((__le64 *) value_ptr(parent, index)) =
cpu_to_le64(dm_block_location(result->block));
return 0;
@@ -186,8 +170,17 @@ static int exit_child(struct dm_btree_info *info, struct child *c)
return dm_tm_unlock(info->tm, c->block);
}
-static void shift(struct node *left, struct node *right, int count)
+static void shift(struct btree_node *left, struct btree_node *right, int count)
{
+ uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
+ uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
+ uint32_t max_entries = le32_to_cpu(left->header.max_entries);
+ uint32_t r_max_entries = le32_to_cpu(right->header.max_entries);
+
+ BUG_ON(max_entries != r_max_entries);
+ BUG_ON(nr_left - count > max_entries);
+ BUG_ON(nr_right + count > max_entries);
+
if (!count)
return;
@@ -199,24 +192,20 @@ static void shift(struct node *left, struct node *right, int count)
node_shift(right, count);
}
- left->header.nr_entries =
- cpu_to_le32(le32_to_cpu(left->header.nr_entries) - count);
- BUG_ON(le32_to_cpu(left->header.nr_entries) > le32_to_cpu(left->header.max_entries));
-
- right->header.nr_entries =
- cpu_to_le32(le32_to_cpu(right->header.nr_entries) + count);
- BUG_ON(le32_to_cpu(right->header.nr_entries) > le32_to_cpu(right->header.max_entries));
+ left->header.nr_entries = cpu_to_le32(nr_left - count);
+ right->header.nr_entries = cpu_to_le32(nr_right + count);
}
-static void __rebalance2(struct dm_btree_info *info, struct node *parent,
+static void __rebalance2(struct dm_btree_info *info, struct btree_node *parent,
struct child *l, struct child *r)
{
- struct node *left = l->n;
- struct node *right = r->n;
+ struct btree_node *left = l->n;
+ struct btree_node *right = r->n;
uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
+ unsigned threshold = 2 * merge_threshold(left) + 1;
- if (nr_left + nr_right <= merge_threshold(left)) {
+ if (nr_left + nr_right < threshold) {
/*
* Merge
*/
@@ -234,28 +223,25 @@ static void __rebalance2(struct dm_btree_info *info, struct node *parent,
* Rebalance.
*/
unsigned target_left = (nr_left + nr_right) / 2;
- unsigned shift_ = nr_left - target_left;
- BUG_ON(le32_to_cpu(left->header.max_entries) <= nr_left - shift_);
- BUG_ON(le32_to_cpu(right->header.max_entries) <= nr_right + shift_);
shift(left, right, nr_left - target_left);
*key_ptr(parent, r->index) = right->keys[0];
}
}
static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info,
- unsigned left_index)
+ struct dm_btree_value_type *vt, unsigned left_index)
{
int r;
- struct node *parent;
+ struct btree_node *parent;
struct child left, right;
parent = dm_block_data(shadow_current(s));
- r = init_child(info, parent, left_index, &left);
+ r = init_child(info, vt, parent, left_index, &left);
if (r)
return r;
- r = init_child(info, parent, left_index + 1, &right);
+ r = init_child(info, vt, parent, left_index + 1, &right);
if (r) {
exit_child(info, &left);
return r;
@@ -272,95 +258,129 @@ static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info,
return exit_child(info, &right);
}
-static void __rebalance3(struct dm_btree_info *info, struct node *parent,
- struct child *l, struct child *c, struct child *r)
+/*
+ * We dump as many entries from center as possible into left, then the rest
+ * in right, then rebalance2. This wastes some cpu, but I want something
+ * simple atm.
+ */
+static void delete_center_node(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *c, struct child *r,
+ struct btree_node *left, struct btree_node *center, struct btree_node *right,
+ uint32_t nr_left, uint32_t nr_center, uint32_t nr_right)
{
- struct node *left = l->n;
- struct node *center = c->n;
- struct node *right = r->n;
-
- uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
- uint32_t nr_center = le32_to_cpu(center->header.nr_entries);
- uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
uint32_t max_entries = le32_to_cpu(left->header.max_entries);
+ unsigned shift = min(max_entries - nr_left, nr_center);
+
+ BUG_ON(nr_left + shift > max_entries);
+ node_copy(left, center, -shift);
+ left->header.nr_entries = cpu_to_le32(nr_left + shift);
+
+ if (shift != nr_center) {
+ shift = nr_center - shift;
+ BUG_ON((nr_right + shift) > max_entries);
+ node_shift(right, shift);
+ node_copy(center, right, shift);
+ right->header.nr_entries = cpu_to_le32(nr_right + shift);
+ }
+ *key_ptr(parent, r->index) = right->keys[0];
- unsigned target;
+ delete_at(parent, c->index);
+ r->index--;
- BUG_ON(left->header.max_entries != center->header.max_entries);
- BUG_ON(center->header.max_entries != right->header.max_entries);
-
- if (((nr_left + nr_center + nr_right) / 2) < merge_threshold(center)) {
- /*
- * Delete center node:
- *
- * We dump as many entries from center as possible into
- * left, then the rest in right, then rebalance2. This
- * wastes some cpu, but I want something simple atm.
- */
- unsigned shift = min(max_entries - nr_left, nr_center);
-
- BUG_ON(nr_left + shift > max_entries);
- node_copy(left, center, -shift);
- left->header.nr_entries = cpu_to_le32(nr_left + shift);
-
- if (shift != nr_center) {
- shift = nr_center - shift;
- BUG_ON((nr_right + shift) >= max_entries);
- node_shift(right, shift);
- node_copy(center, right, shift);
- right->header.nr_entries = cpu_to_le32(nr_right + shift);
- }
- *key_ptr(parent, r->index) = right->keys[0];
+ dm_tm_dec(info->tm, dm_block_location(c->block));
+ __rebalance2(info, parent, l, r);
+}
- delete_at(parent, c->index);
- r->index--;
+/*
+ * Redistributes entries among 3 sibling nodes.
+ */
+static void redistribute3(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *c, struct child *r,
+ struct btree_node *left, struct btree_node *center, struct btree_node *right,
+ uint32_t nr_left, uint32_t nr_center, uint32_t nr_right)
+{
+ int s;
+ uint32_t max_entries = le32_to_cpu(left->header.max_entries);
+ unsigned target = (nr_left + nr_center + nr_right) / 3;
+ BUG_ON(target > max_entries);
- dm_tm_dec(info->tm, dm_block_location(c->block));
- __rebalance2(info, parent, l, r);
+ if (nr_left < nr_right) {
+ s = nr_left - target;
- return;
- }
+ if (s < 0 && nr_center < -s) {
+ /* not enough in central node */
+ shift(left, center, nr_center);
+ s = nr_center - target;
+ shift(left, right, s);
+ nr_right += s;
+ } else
+ shift(left, center, s);
- /*
- * Rebalance
- */
- target = (nr_left + nr_center + nr_right) / 3;
- BUG_ON(target > max_entries);
+ shift(center, right, target - nr_right);
- /*
- * Adjust the left node
- */
- shift(left, center, nr_left - target);
+ } else {
+ s = target - nr_right;
+ if (s > 0 && nr_center < s) {
+ /* not enough in central node */
+ shift(center, right, nr_center);
+ s = target - nr_center;
+ shift(left, right, s);
+ nr_left -= s;
+ } else
+ shift(center, right, s);
+
+ shift(left, center, nr_left - target);
+ }
- /*
- * Adjust the right node
- */
- shift(center, right, target - nr_right);
*key_ptr(parent, c->index) = center->keys[0];
*key_ptr(parent, r->index) = right->keys[0];
}
+static void __rebalance3(struct dm_btree_info *info, struct btree_node *parent,
+ struct child *l, struct child *c, struct child *r)
+{
+ struct btree_node *left = l->n;
+ struct btree_node *center = c->n;
+ struct btree_node *right = r->n;
+
+ uint32_t nr_left = le32_to_cpu(left->header.nr_entries);
+ uint32_t nr_center = le32_to_cpu(center->header.nr_entries);
+ uint32_t nr_right = le32_to_cpu(right->header.nr_entries);
+
+ unsigned threshold = merge_threshold(left) * 4 + 1;
+
+ BUG_ON(left->header.max_entries != center->header.max_entries);
+ BUG_ON(center->header.max_entries != right->header.max_entries);
+
+ if ((nr_left + nr_center + nr_right) < threshold)
+ delete_center_node(info, parent, l, c, r, left, center, right,
+ nr_left, nr_center, nr_right);
+ else
+ redistribute3(info, parent, l, c, r, left, center, right,
+ nr_left, nr_center, nr_right);
+}
+
static int rebalance3(struct shadow_spine *s, struct dm_btree_info *info,
- unsigned left_index)
+ struct dm_btree_value_type *vt, unsigned left_index)
{
int r;
- struct node *parent = dm_block_data(shadow_current(s));
+ struct btree_node *parent = dm_block_data(shadow_current(s));
struct child left, center, right;
/*
* FIXME: fill out an array?
*/
- r = init_child(info, parent, left_index, &left);
+ r = init_child(info, vt, parent, left_index, &left);
if (r)
return r;
- r = init_child(info, parent, left_index + 1, &center);
+ r = init_child(info, vt, parent, left_index + 1, &center);
if (r) {
exit_child(info, &left);
return r;
}
- r = init_child(info, parent, left_index + 2, &right);
+ r = init_child(info, vt, parent, left_index + 2, &right);
if (r) {
exit_child(info, &left);
exit_child(info, &center);
@@ -394,7 +414,7 @@ static int get_nr_entries(struct dm_transaction_manager *tm,
{
int r;
struct dm_block *block;
- struct node *n;
+ struct btree_node *n;
r = dm_tm_read_lock(tm, b, &btree_node_validator, &block);
if (r)
@@ -407,11 +427,12 @@ static int get_nr_entries(struct dm_transaction_manager *tm,
}
static int rebalance_children(struct shadow_spine *s,
- struct dm_btree_info *info, uint64_t key)
+ 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 node *n;
+ struct btree_node *n;
n = dm_block_data(shadow_current(s));
@@ -441,25 +462,22 @@ static int rebalance_children(struct shadow_spine *s,
if (r)
return r;
- if (child_entries > del_threshold(n))
- return 0;
-
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, i);
+ r = rebalance2(s, info, vt, i);
else if (!has_right_sibling)
- r = rebalance2(s, info, i - 1);
+ r = rebalance2(s, info, vt, i - 1);
else
- r = rebalance3(s, info, i - 1);
+ r = rebalance3(s, info, vt, i - 1);
return r;
}
-static int do_leaf(struct node *n, uint64_t key, unsigned *index)
+static int do_leaf(struct btree_node *n, uint64_t key, unsigned *index)
{
int i = lower_bound(n, key);
@@ -482,7 +500,7 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
uint64_t key, unsigned *index)
{
int i = *index, r;
- struct node *n;
+ struct btree_node *n;
for (;;) {
r = shadow_step(s, root, vt);
@@ -496,7 +514,7 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
*/
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, sizeof(__le64)),
+ memcpy(value_ptr(dm_block_data(shadow_parent(s)), i),
&location, sizeof(__le64));
}
@@ -505,7 +523,7 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
if (le32_to_cpu(n->header.flags) & LEAF_NODE)
return do_leaf(n, key, index);
- r = rebalance_children(s, info, key);
+ r = rebalance_children(s, info, vt, key);
if (r)
break;
@@ -526,13 +544,21 @@ static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info,
return r;
}
+static struct dm_btree_value_type le64_type = {
+ .context = NULL,
+ .size = sizeof(__le64),
+ .inc = NULL,
+ .dec = NULL,
+ .equal = NULL
+};
+
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 node *n;
+ struct btree_node *n;
init_shadow_spine(&spine, info);
for (level = 0; level < info->levels; level++) {
@@ -553,7 +579,7 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
if (info->value_type.dec)
info->value_type.dec(info->value_type.context,
- value_ptr(n, index, info->value_type.size));
+ value_ptr(n, index));
delete_at(n, index);
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 13:12:58 +0000