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-rw-r--r--drivers/md/persistent-data/dm-btree.c1625
1 files changed, 1625 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
new file mode 100644
index 000000000..1cc783d70
--- /dev/null
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -0,0 +1,1625 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-btree-internal.h"
+#include "dm-space-map.h"
+#include "dm-transaction-manager.h"
+
+#include <linux/export.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "btree"
+
+/*----------------------------------------------------------------
+ * Array manipulation
+ *--------------------------------------------------------------*/
+static void memcpy_disk(void *dest, const void *src, size_t len)
+ __dm_written_to_disk(src)
+{
+ memcpy(dest, src, len);
+ __dm_unbless_for_disk(src);
+}
+
+static void array_insert(void *base, size_t elt_size, unsigned int nr_elts,
+ unsigned int index, void *elt)
+ __dm_written_to_disk(elt)
+{
+ if (index < nr_elts)
+ memmove(base + (elt_size * (index + 1)),
+ base + (elt_size * index),
+ (nr_elts - index) * elt_size);
+
+ memcpy_disk(base + (elt_size * index), elt, elt_size);
+}
+
+/*----------------------------------------------------------------*/
+
+/* makes the assumption that no two keys are the same. */
+static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
+{
+ int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
+
+ while (hi - lo > 1) {
+ int mid = lo + ((hi - lo) / 2);
+ uint64_t mid_key = le64_to_cpu(n->keys[mid]);
+
+ if (mid_key == key)
+ return mid;
+
+ if (mid_key < key)
+ lo = mid;
+ else
+ hi = mid;
+ }
+
+ return want_hi ? hi : lo;
+}
+
+int lower_bound(struct btree_node *n, uint64_t key)
+{
+ return bsearch(n, key, 0);
+}
+
+static int upper_bound(struct btree_node *n, uint64_t key)
+{
+ return bsearch(n, key, 1);
+}
+
+void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
+ struct dm_btree_value_type *vt)
+{
+ uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
+
+ if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
+ dm_tm_with_runs(tm, value_ptr(n, 0), nr_entries, dm_tm_inc_range);
+
+ else if (vt->inc)
+ vt->inc(vt->context, value_ptr(n, 0), nr_entries);
+}
+
+static int insert_at(size_t value_size, struct btree_node *node, unsigned int index,
+ uint64_t key, void *value)
+ __dm_written_to_disk(value)
+{
+ uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
+ uint32_t max_entries = le32_to_cpu(node->header.max_entries);
+ __le64 key_le = cpu_to_le64(key);
+
+ if (index > nr_entries ||
+ index >= max_entries ||
+ nr_entries >= max_entries) {
+ DMERR("too many entries in btree node for insert");
+ __dm_unbless_for_disk(value);
+ return -ENOMEM;
+ }
+
+ __dm_bless_for_disk(&key_le);
+
+ array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
+ array_insert(value_base(node), value_size, nr_entries, index, value);
+ node->header.nr_entries = cpu_to_le32(nr_entries + 1);
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * We want 3n entries (for some n). This works more nicely for repeated
+ * insert remove loops than (2n + 1).
+ */
+static uint32_t calc_max_entries(size_t value_size, size_t block_size)
+{
+ uint32_t total, n;
+ size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */
+
+ block_size -= sizeof(struct node_header);
+ total = block_size / elt_size;
+ n = total / 3; /* rounds down */
+
+ return 3 * n;
+}
+
+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);
+ unlock_block(info, b);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_btree_empty);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Deletion uses a recursive algorithm, since we have limited stack space
+ * we explicitly manage our own stack on the heap.
+ */
+#define MAX_SPINE_DEPTH 64
+struct frame {
+ struct dm_block *b;
+ struct btree_node *n;
+ unsigned int level;
+ unsigned int nr_children;
+ unsigned int current_child;
+};
+
+struct del_stack {
+ struct dm_btree_info *info;
+ struct dm_transaction_manager *tm;
+ int top;
+ struct frame spine[MAX_SPINE_DEPTH];
+};
+
+static int top_frame(struct del_stack *s, struct frame **f)
+{
+ if (s->top < 0) {
+ DMERR("btree deletion stack empty");
+ return -EINVAL;
+ }
+
+ *f = s->spine + s->top;
+
+ return 0;
+}
+
+static int unprocessed_frames(struct del_stack *s)
+{
+ return s->top >= 0;
+}
+
+static void prefetch_children(struct del_stack *s, struct frame *f)
+{
+ unsigned int i;
+ struct dm_block_manager *bm = dm_tm_get_bm(s->tm);
+
+ for (i = 0; i < f->nr_children; i++)
+ dm_bm_prefetch(bm, value64(f->n, i));
+}
+
+static bool is_internal_level(struct dm_btree_info *info, struct frame *f)
+{
+ return f->level < (info->levels - 1);
+}
+
+static int push_frame(struct del_stack *s, dm_block_t b, unsigned int 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;
+}
+
+static void pop_frame(struct del_stack *s)
+{
+ struct frame *f = s->spine + s->top--;
+
+ dm_tm_dec(s->tm, dm_block_location(f->b));
+ dm_tm_unlock(s->tm, f->b);
+}
+
+static void unlock_all_frames(struct del_stack *s)
+{
+ struct frame *f;
+
+ while (unprocessed_frames(s)) {
+ f = s->spine + s->top--;
+ dm_tm_unlock(s->tm, f->b);
+ }
+}
+
+int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
+{
+ int r;
+ struct del_stack *s;
+
+ /*
+ * dm_btree_del() is called via an ioctl, as such should be
+ * considered an FS op. We can't recurse back into the FS, so we
+ * allocate GFP_NOFS.
+ */
+ s = kmalloc(sizeof(*s), GFP_NOFS);
+ if (!s)
+ return -ENOMEM;
+ s->info = info;
+ s->tm = info->tm;
+ s->top = -1;
+
+ r = push_frame(s, root, 0);
+ if (r)
+ goto out;
+
+ while (unprocessed_frames(s)) {
+ uint32_t flags;
+ struct frame *f;
+ dm_block_t b;
+
+ r = top_frame(s, &f);
+ if (r)
+ goto out;
+
+ if (f->current_child >= f->nr_children) {
+ pop_frame(s);
+ continue;
+ }
+
+ flags = le32_to_cpu(f->n->header.flags);
+ if (flags & INTERNAL_NODE) {
+ b = value64(f->n, f->current_child);
+ f->current_child++;
+ r = push_frame(s, b, f->level);
+ if (r)
+ goto out;
+
+ } else if (is_internal_level(info, f)) {
+ b = value64(f->n, f->current_child);
+ f->current_child++;
+ r = push_frame(s, b, f->level + 1);
+ if (r)
+ goto out;
+
+ } else {
+ if (info->value_type.dec)
+ info->value_type.dec(info->value_type.context,
+ value_ptr(f->n, 0), f->nr_children);
+ pop_frame(s);
+ }
+ }
+out:
+ if (r) {
+ /* cleanup all frames of del_stack */
+ unlock_all_frames(s);
+ }
+ kfree(s);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_del);
+
+/*----------------------------------------------------------------*/
+
+static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
+ int (*search_fn)(struct btree_node *, uint64_t),
+ uint64_t *result_key, void *v, size_t value_size)
+{
+ int i, r;
+ uint32_t flags, nr_entries;
+
+ do {
+ r = ro_step(s, block);
+ if (r < 0)
+ return r;
+
+ i = search_fn(ro_node(s), key);
+
+ flags = le32_to_cpu(ro_node(s)->header.flags);
+ nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
+ if (i < 0 || i >= nr_entries)
+ return -ENODATA;
+
+ if (flags & INTERNAL_NODE)
+ block = value64(ro_node(s), i);
+
+ } while (!(flags & LEAF_NODE));
+
+ *result_key = le64_to_cpu(ro_node(s)->keys[i]);
+ if (v)
+ memcpy(v, value_ptr(ro_node(s), i), value_size);
+
+ return 0;
+}
+
+int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value_le)
+{
+ unsigned int level, last_level = info->levels - 1;
+ int r = -ENODATA;
+ uint64_t rkey;
+ __le64 internal_value_le;
+ struct ro_spine spine;
+
+ init_ro_spine(&spine, info);
+ for (level = 0; level < info->levels; level++) {
+ size_t size;
+ void *value_p;
+
+ if (level == last_level) {
+ value_p = value_le;
+ size = info->value_type.size;
+
+ } else {
+ value_p = &internal_value_le;
+ size = sizeof(uint64_t);
+ }
+
+ r = btree_lookup_raw(&spine, root, keys[level],
+ lower_bound, &rkey,
+ value_p, size);
+
+ if (!r) {
+ if (rkey != keys[level]) {
+ exit_ro_spine(&spine);
+ return -ENODATA;
+ }
+ } else {
+ exit_ro_spine(&spine);
+ return r;
+ }
+
+ root = le64_to_cpu(internal_value_le);
+ }
+ exit_ro_spine(&spine);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_lookup);
+
+static int dm_btree_lookup_next_single(struct dm_btree_info *info, dm_block_t root,
+ uint64_t key, uint64_t *rkey, void *value_le)
+{
+ int r, i;
+ uint32_t flags, nr_entries;
+ struct dm_block *node;
+ struct btree_node *n;
+
+ r = bn_read_lock(info, root, &node);
+ if (r)
+ return r;
+
+ n = dm_block_data(node);
+ flags = le32_to_cpu(n->header.flags);
+ nr_entries = le32_to_cpu(n->header.nr_entries);
+
+ if (flags & INTERNAL_NODE) {
+ i = lower_bound(n, key);
+ if (i < 0) {
+ /*
+ * avoid early -ENODATA return when all entries are
+ * higher than the search @key.
+ */
+ i = 0;
+ }
+ if (i >= nr_entries) {
+ r = -ENODATA;
+ goto out;
+ }
+
+ r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
+ if (r == -ENODATA && i < (nr_entries - 1)) {
+ i++;
+ r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
+ }
+
+ } else {
+ i = upper_bound(n, key);
+ if (i < 0 || i >= nr_entries) {
+ r = -ENODATA;
+ goto out;
+ }
+
+ *rkey = le64_to_cpu(n->keys[i]);
+ memcpy(value_le, value_ptr(n, i), info->value_type.size);
+ }
+out:
+ dm_tm_unlock(info->tm, node);
+ return r;
+}
+
+int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, uint64_t *rkey, void *value_le)
+{
+ unsigned int level;
+ int r = -ENODATA;
+ __le64 internal_value_le;
+ struct ro_spine spine;
+
+ init_ro_spine(&spine, info);
+ for (level = 0; level < info->levels - 1u; level++) {
+ r = btree_lookup_raw(&spine, root, keys[level],
+ lower_bound, rkey,
+ &internal_value_le, sizeof(uint64_t));
+ if (r)
+ goto out;
+
+ if (*rkey != keys[level]) {
+ r = -ENODATA;
+ goto out;
+ }
+
+ root = le64_to_cpu(internal_value_le);
+ }
+
+ r = dm_btree_lookup_next_single(info, root, keys[level], rkey, value_le);
+out:
+ exit_ro_spine(&spine);
+ return r;
+}
+
+EXPORT_SYMBOL_GPL(dm_btree_lookup_next);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Copies entries from one region of a btree node to another. The regions
+ * must not overlap.
+ */
+static void copy_entries(struct btree_node *dest, unsigned int dest_offset,
+ struct btree_node *src, unsigned int src_offset,
+ unsigned int count)
+{
+ size_t value_size = le32_to_cpu(dest->header.value_size);
+ memcpy(dest->keys + dest_offset, src->keys + src_offset, count * sizeof(uint64_t));
+ memcpy(value_ptr(dest, dest_offset), value_ptr(src, src_offset), count * value_size);
+}
+
+/*
+ * Moves entries from one region fo a btree node to another. The regions
+ * may overlap.
+ */
+static void move_entries(struct btree_node *dest, unsigned int dest_offset,
+ struct btree_node *src, unsigned int src_offset,
+ unsigned int count)
+{
+ size_t value_size = le32_to_cpu(dest->header.value_size);
+ memmove(dest->keys + dest_offset, src->keys + src_offset, count * sizeof(uint64_t));
+ memmove(value_ptr(dest, dest_offset), value_ptr(src, src_offset), count * value_size);
+}
+
+/*
+ * Erases the first 'count' entries of a btree node, shifting following
+ * entries down into their place.
+ */
+static void shift_down(struct btree_node *n, unsigned int count)
+{
+ move_entries(n, 0, n, count, le32_to_cpu(n->header.nr_entries) - count);
+}
+
+/*
+ * Moves entries in a btree node up 'count' places, making space for
+ * new entries at the start of the node.
+ */
+static void shift_up(struct btree_node *n, unsigned int count)
+{
+ move_entries(n, count, n, 0, le32_to_cpu(n->header.nr_entries));
+}
+
+/*
+ * Redistributes entries between two btree nodes to make them
+ * have similar numbers of entries.
+ */
+static void redistribute2(struct btree_node *left, struct btree_node *right)
+{
+ unsigned int nr_left = le32_to_cpu(left->header.nr_entries);
+ unsigned int nr_right = le32_to_cpu(right->header.nr_entries);
+ unsigned int total = nr_left + nr_right;
+ unsigned int target_left = total / 2;
+ unsigned int target_right = total - target_left;
+
+ if (nr_left < target_left) {
+ unsigned int delta = target_left - nr_left;
+ copy_entries(left, nr_left, right, 0, delta);
+ shift_down(right, delta);
+ } else if (nr_left > target_left) {
+ unsigned int delta = nr_left - target_left;
+ if (nr_right)
+ shift_up(right, delta);
+ copy_entries(right, 0, left, target_left, delta);
+ }
+
+ left->header.nr_entries = cpu_to_le32(target_left);
+ right->header.nr_entries = cpu_to_le32(target_right);
+}
+
+/*
+ * Redistribute entries between three nodes. Assumes the central
+ * node is empty.
+ */
+static void redistribute3(struct btree_node *left, struct btree_node *center,
+ struct btree_node *right)
+{
+ unsigned int nr_left = le32_to_cpu(left->header.nr_entries);
+ unsigned int nr_center = le32_to_cpu(center->header.nr_entries);
+ unsigned int nr_right = le32_to_cpu(right->header.nr_entries);
+ unsigned int total, target_left, target_center, target_right;
+
+ BUG_ON(nr_center);
+
+ total = nr_left + nr_right;
+ target_left = total / 3;
+ target_center = (total - target_left) / 2;
+ target_right = (total - target_left - target_center);
+
+ if (nr_left < target_left) {
+ unsigned int left_short = target_left - nr_left;
+ copy_entries(left, nr_left, right, 0, left_short);
+ copy_entries(center, 0, right, left_short, target_center);
+ shift_down(right, nr_right - target_right);
+
+ } else if (nr_left < (target_left + target_center)) {
+ unsigned int left_to_center = nr_left - target_left;
+ copy_entries(center, 0, left, target_left, left_to_center);
+ copy_entries(center, left_to_center, right, 0, target_center - left_to_center);
+ shift_down(right, nr_right - target_right);
+
+ } else {
+ unsigned int right_short = target_right - nr_right;
+ shift_up(right, right_short);
+ copy_entries(right, 0, left, nr_left - right_short, right_short);
+ copy_entries(center, 0, left, target_left, nr_left - target_left);
+ }
+
+ left->header.nr_entries = cpu_to_le32(target_left);
+ center->header.nr_entries = cpu_to_le32(target_center);
+ right->header.nr_entries = cpu_to_le32(target_right);
+}
+
+/*
+ * 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 split_one_into_two(struct shadow_spine *s, unsigned int parent_index,
+ struct dm_btree_value_type *vt, uint64_t key)
+{
+ int r;
+ 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);
+
+ rn->header.flags = ln->header.flags;
+ rn->header.nr_entries = cpu_to_le32(0);
+ rn->header.max_entries = ln->header.max_entries;
+ rn->header.value_size = ln->header.value_size;
+ redistribute2(ln, rn);
+
+ /* patch up the parent */
+ parent = shadow_parent(s);
+ pn = dm_block_data(parent);
+
+ 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) {
+ unlock_block(s->info, right);
+ return r;
+ }
+
+ /* patch up the spine */
+ 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;
+}
+
+/*
+ * We often need to modify a sibling node. This function shadows a particular
+ * child of the given parent node. Making sure to update the parent to point
+ * to the new shadow.
+ */
+static int shadow_child(struct dm_btree_info *info, struct dm_btree_value_type *vt,
+ struct btree_node *parent, unsigned int index,
+ struct dm_block **result)
+{
+ int r, inc;
+ dm_block_t root;
+ struct btree_node *node;
+
+ root = value64(parent, index);
+
+ r = dm_tm_shadow_block(info->tm, root, &btree_node_validator,
+ result, &inc);
+ if (r)
+ return r;
+
+ node = dm_block_data(*result);
+
+ if (inc)
+ inc_children(info->tm, node, vt);
+
+ *((__le64 *) value_ptr(parent, index)) =
+ cpu_to_le64(dm_block_location(*result));
+
+ return 0;
+}
+
+/*
+ * Splits two nodes into three. This is more work, but results in fuller
+ * nodes, so saves metadata space.
+ */
+static int split_two_into_three(struct shadow_spine *s, unsigned int parent_index,
+ struct dm_btree_value_type *vt, uint64_t key)
+{
+ int r;
+ unsigned int middle_index;
+ struct dm_block *left, *middle, *right, *parent;
+ struct btree_node *ln, *rn, *mn, *pn;
+ __le64 location;
+
+ parent = shadow_parent(s);
+ pn = dm_block_data(parent);
+
+ if (parent_index == 0) {
+ middle_index = 1;
+ left = shadow_current(s);
+ r = shadow_child(s->info, vt, pn, parent_index + 1, &right);
+ if (r)
+ return r;
+ } else {
+ middle_index = parent_index;
+ right = shadow_current(s);
+ r = shadow_child(s->info, vt, pn, parent_index - 1, &left);
+ if (r)
+ return r;
+ }
+
+ r = new_block(s->info, &middle);
+ if (r < 0)
+ return r;
+
+ ln = dm_block_data(left);
+ mn = dm_block_data(middle);
+ rn = dm_block_data(right);
+
+ mn->header.nr_entries = cpu_to_le32(0);
+ mn->header.flags = ln->header.flags;
+ mn->header.max_entries = ln->header.max_entries;
+ mn->header.value_size = ln->header.value_size;
+
+ redistribute3(ln, mn, rn);
+
+ /* patch up the parent */
+ pn->keys[middle_index] = rn->keys[0];
+ location = cpu_to_le64(dm_block_location(middle));
+ __dm_bless_for_disk(&location);
+ r = insert_at(sizeof(__le64), pn, middle_index,
+ le64_to_cpu(mn->keys[0]), &location);
+ if (r) {
+ if (shadow_current(s) != left)
+ unlock_block(s->info, left);
+
+ unlock_block(s->info, middle);
+
+ if (shadow_current(s) != right)
+ unlock_block(s->info, right);
+
+ return r;
+ }
+
+
+ /* patch up the spine */
+ if (key < le64_to_cpu(mn->keys[0])) {
+ unlock_block(s->info, middle);
+ unlock_block(s->info, right);
+ s->nodes[1] = left;
+ } else if (key < le64_to_cpu(rn->keys[0])) {
+ unlock_block(s->info, left);
+ unlock_block(s->info, right);
+ s->nodes[1] = middle;
+ } else {
+ unlock_block(s->info, left);
+ unlock_block(s->info, middle);
+ 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 int nr_left, nr_right;
+ struct dm_block *left, *right, *new_parent;
+ struct btree_node *pn, *ln, *rn;
+ __le64 val;
+
+ new_parent = shadow_current(s);
+
+ pn = dm_block_data(new_parent);
+ size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
+ sizeof(__le64) : s->info->value_type.size;
+
+ /* create & init the left block */
+ r = new_block(s->info, &left);
+ if (r < 0)
+ return r;
+
+ ln = dm_block_data(left);
+ nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
+
+ 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;
+ memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
+ memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size);
+
+ /* create & init the right block */
+ r = new_block(s->info, &right);
+ if (r < 0) {
+ unlock_block(s->info, left);
+ return r;
+ }
+
+ rn = dm_block_data(right);
+ nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
+
+ 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(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
+ 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));
+
+ unlock_block(s->info, left);
+ unlock_block(s->info, right);
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Redistributes a node's entries with its left sibling.
+ */
+static int rebalance_left(struct shadow_spine *s, struct dm_btree_value_type *vt,
+ unsigned int parent_index, uint64_t key)
+{
+ int r;
+ struct dm_block *sib;
+ struct btree_node *left, *right, *parent = dm_block_data(shadow_parent(s));
+
+ r = shadow_child(s->info, vt, parent, parent_index - 1, &sib);
+ if (r)
+ return r;
+
+ left = dm_block_data(sib);
+ right = dm_block_data(shadow_current(s));
+ redistribute2(left, right);
+ *key_ptr(parent, parent_index) = right->keys[0];
+
+ if (key < le64_to_cpu(right->keys[0])) {
+ unlock_block(s->info, s->nodes[1]);
+ s->nodes[1] = sib;
+ } else {
+ unlock_block(s->info, sib);
+ }
+
+ return 0;
+}
+
+/*
+ * Redistributes a nodes entries with its right sibling.
+ */
+static int rebalance_right(struct shadow_spine *s, struct dm_btree_value_type *vt,
+ unsigned int parent_index, uint64_t key)
+{
+ int r;
+ struct dm_block *sib;
+ struct btree_node *left, *right, *parent = dm_block_data(shadow_parent(s));
+
+ r = shadow_child(s->info, vt, parent, parent_index + 1, &sib);
+ if (r)
+ return r;
+
+ left = dm_block_data(shadow_current(s));
+ right = dm_block_data(sib);
+ redistribute2(left, right);
+ *key_ptr(parent, parent_index + 1) = right->keys[0];
+
+ if (key < le64_to_cpu(right->keys[0])) {
+ unlock_block(s->info, sib);
+ } else {
+ unlock_block(s->info, s->nodes[1]);
+ s->nodes[1] = sib;
+ }
+
+ return 0;
+}
+
+/*
+ * Returns the number of spare entries in a node.
+ */
+static int get_node_free_space(struct dm_btree_info *info, dm_block_t b, unsigned int *space)
+{
+ int r;
+ unsigned int nr_entries;
+ struct dm_block *block;
+ struct btree_node *node;
+
+ r = bn_read_lock(info, b, &block);
+ if (r)
+ return r;
+
+ node = dm_block_data(block);
+ nr_entries = le32_to_cpu(node->header.nr_entries);
+ *space = le32_to_cpu(node->header.max_entries) - nr_entries;
+
+ unlock_block(info, block);
+ return 0;
+}
+
+/*
+ * Make space in a node, either by moving some entries to a sibling,
+ * or creating a new sibling node. SPACE_THRESHOLD defines the minimum
+ * number of free entries that must be in the sibling to make the move
+ * worth while. If the siblings are shared (eg, part of a snapshot),
+ * then they are not touched, since this break sharing and so consume
+ * more space than we save.
+ */
+#define SPACE_THRESHOLD 8
+static int rebalance_or_split(struct shadow_spine *s, struct dm_btree_value_type *vt,
+ unsigned int parent_index, uint64_t key)
+{
+ int r;
+ struct btree_node *parent = dm_block_data(shadow_parent(s));
+ unsigned int nr_parent = le32_to_cpu(parent->header.nr_entries);
+ unsigned int free_space;
+ int left_shared = 0, right_shared = 0;
+
+ /* Should we move entries to the left sibling? */
+ if (parent_index > 0) {
+ dm_block_t left_b = value64(parent, parent_index - 1);
+ r = dm_tm_block_is_shared(s->info->tm, left_b, &left_shared);
+ if (r)
+ return r;
+
+ if (!left_shared) {
+ r = get_node_free_space(s->info, left_b, &free_space);
+ if (r)
+ return r;
+
+ if (free_space >= SPACE_THRESHOLD)
+ return rebalance_left(s, vt, parent_index, key);
+ }
+ }
+
+ /* Should we move entries to the right sibling? */
+ if (parent_index < (nr_parent - 1)) {
+ dm_block_t right_b = value64(parent, parent_index + 1);
+ r = dm_tm_block_is_shared(s->info->tm, right_b, &right_shared);
+ if (r)
+ return r;
+
+ if (!right_shared) {
+ r = get_node_free_space(s->info, right_b, &free_space);
+ if (r)
+ return r;
+
+ if (free_space >= SPACE_THRESHOLD)
+ return rebalance_right(s, vt, parent_index, key);
+ }
+ }
+
+ /*
+ * We need to split the node, normally we split two nodes
+ * into three. But when inserting a sequence that is either
+ * monotonically increasing or decreasing it's better to split
+ * a single node into two.
+ */
+ if (left_shared || right_shared || (nr_parent <= 2) ||
+ (parent_index == 0) || (parent_index + 1 == nr_parent)) {
+ return split_one_into_two(s, parent_index, vt, key);
+ } else {
+ return split_two_into_three(s, parent_index, vt, key);
+ }
+}
+
+/*
+ * Does the node contain a particular key?
+ */
+static bool contains_key(struct btree_node *node, uint64_t key)
+{
+ int i = lower_bound(node, key);
+
+ if (i >= 0 && le64_to_cpu(node->keys[i]) == key)
+ return true;
+
+ return false;
+}
+
+/*
+ * In general we preemptively make sure there's a free entry in every
+ * node on the spine when doing an insert. But we can avoid that with
+ * leaf nodes if we know it's an overwrite.
+ */
+static bool has_space_for_insert(struct btree_node *node, uint64_t key)
+{
+ if (node->header.nr_entries == node->header.max_entries) {
+ if (le32_to_cpu(node->header.flags) & LEAF_NODE) {
+ /* we don't need space if it's an overwrite */
+ return contains_key(node, key);
+ }
+
+ return false;
+ }
+
+ return true;
+}
+
+static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
+ struct dm_btree_value_type *vt,
+ uint64_t key, unsigned int *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 (!has_space_for_insert(node, key)) {
+ if (top)
+ r = btree_split_beneath(s, key);
+ else
+ r = rebalance_or_split(s, vt, i, key);
+
+ if (r < 0)
+ return r;
+
+ /* making space can cause the current node to change */
+ 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;
+}
+
+static int __btree_get_overwrite_leaf(struct shadow_spine *s, dm_block_t root,
+ uint64_t key, int *index)
+{
+ int r, i = -1;
+ struct btree_node *node;
+
+ *index = 0;
+ for (;;) {
+ r = shadow_step(s, root, &s->info->value_type);
+ 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) {
+ __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));
+ i = lower_bound(node, key);
+
+ BUG_ON(i < 0);
+ BUG_ON(i >= le32_to_cpu(node->header.nr_entries));
+
+ if (le32_to_cpu(node->header.flags) & LEAF_NODE) {
+ if (key != le64_to_cpu(node->keys[i]))
+ return -EINVAL;
+ break;
+ }
+
+ root = value64(node, i);
+ }
+
+ *index = i;
+ return 0;
+}
+
+int btree_get_overwrite_leaf(struct dm_btree_info *info, dm_block_t root,
+ uint64_t key, int *index,
+ dm_block_t *new_root, struct dm_block **leaf)
+{
+ int r;
+ struct shadow_spine spine;
+
+ BUG_ON(info->levels > 1);
+ init_shadow_spine(&spine, info);
+ r = __btree_get_overwrite_leaf(&spine, root, key, index);
+ if (!r) {
+ *new_root = shadow_root(&spine);
+ *leaf = shadow_current(&spine);
+
+ /*
+ * Decrement the count so exit_shadow_spine() doesn't
+ * unlock the leaf.
+ */
+ spine.count--;
+ }
+ exit_shadow_spine(&spine);
+
+ return r;
+}
+
+static bool need_insert(struct btree_node *node, uint64_t *keys,
+ unsigned int level, unsigned int index)
+{
+ return ((index >= le32_to_cpu(node->header.nr_entries)) ||
+ (le64_to_cpu(node->keys[index]) != keys[level]));
+}
+
+static int insert(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root,
+ int *inserted)
+ __dm_written_to_disk(value)
+{
+ int r;
+ unsigned int level, index = -1, last_level = info->levels - 1;
+ dm_block_t block = root;
+ struct shadow_spine spine;
+ struct btree_node *n;
+ struct dm_btree_value_type le64_type;
+
+ init_le64_type(info->tm, &le64_type);
+ init_shadow_spine(&spine, info);
+
+ for (level = 0; level < (info->levels - 1); level++) {
+ r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index);
+ if (r < 0)
+ goto bad;
+
+ n = dm_block_data(shadow_current(&spine));
+
+ if (need_insert(n, keys, level, index)) {
+ dm_block_t new_tree;
+ __le64 new_le;
+
+ r = dm_btree_empty(info, &new_tree);
+ if (r < 0)
+ goto bad;
+
+ new_le = cpu_to_le64(new_tree);
+ __dm_bless_for_disk(&new_le);
+
+ r = insert_at(sizeof(uint64_t), n, index,
+ keys[level], &new_le);
+ if (r)
+ goto bad;
+ }
+
+ if (level < last_level)
+ block = value64(n, index);
+ }
+
+ r = btree_insert_raw(&spine, block, &info->value_type,
+ keys[level], &index);
+ if (r < 0)
+ goto bad;
+
+ n = dm_block_data(shadow_current(&spine));
+
+ if (need_insert(n, keys, level, index)) {
+ if (inserted)
+ *inserted = 1;
+
+ r = insert_at(info->value_type.size, n, index,
+ keys[level], value);
+ if (r)
+ goto bad_unblessed;
+ } else {
+ if (inserted)
+ *inserted = 0;
+
+ if (info->value_type.dec &&
+ (!info->value_type.equal ||
+ !info->value_type.equal(
+ info->value_type.context,
+ value_ptr(n, index),
+ value))) {
+ info->value_type.dec(info->value_type.context,
+ value_ptr(n, index), 1);
+ }
+ memcpy_disk(value_ptr(n, index),
+ value, info->value_type.size);
+ }
+
+ *new_root = shadow_root(&spine);
+ exit_shadow_spine(&spine);
+
+ return 0;
+
+bad:
+ __dm_unbless_for_disk(value);
+bad_unblessed:
+ exit_shadow_spine(&spine);
+ return r;
+}
+
+int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root)
+ __dm_written_to_disk(value)
+{
+ return insert(info, root, keys, value, new_root, NULL);
+}
+EXPORT_SYMBOL_GPL(dm_btree_insert);
+
+int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *keys, void *value, dm_block_t *new_root,
+ int *inserted)
+ __dm_written_to_disk(value)
+{
+ return insert(info, root, keys, value, new_root, inserted);
+}
+EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
+
+/*----------------------------------------------------------------*/
+
+static int find_key(struct ro_spine *s, dm_block_t block, bool find_highest,
+ uint64_t *result_key, dm_block_t *next_block)
+{
+ int i, r;
+ uint32_t flags;
+
+ do {
+ r = ro_step(s, block);
+ if (r < 0)
+ return r;
+
+ flags = le32_to_cpu(ro_node(s)->header.flags);
+ i = le32_to_cpu(ro_node(s)->header.nr_entries);
+ if (!i)
+ return -ENODATA;
+ else
+ i--;
+
+ if (find_highest)
+ *result_key = le64_to_cpu(ro_node(s)->keys[i]);
+ else
+ *result_key = le64_to_cpu(ro_node(s)->keys[0]);
+
+ if (next_block || flags & INTERNAL_NODE) {
+ if (find_highest)
+ block = value64(ro_node(s), i);
+ else
+ block = value64(ro_node(s), 0);
+ }
+
+ } while (flags & INTERNAL_NODE);
+
+ if (next_block)
+ *next_block = block;
+ return 0;
+}
+
+static int dm_btree_find_key(struct dm_btree_info *info, dm_block_t root,
+ bool find_highest, uint64_t *result_keys)
+{
+ int r = 0, count = 0, level;
+ struct ro_spine spine;
+
+ init_ro_spine(&spine, info);
+ for (level = 0; level < info->levels; level++) {
+ r = find_key(&spine, root, find_highest, result_keys + level,
+ level == info->levels - 1 ? NULL : &root);
+ if (r == -ENODATA) {
+ r = 0;
+ break;
+
+ } else if (r)
+ break;
+
+ count++;
+ }
+ exit_ro_spine(&spine);
+
+ return r ? r : count;
+}
+
+int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys)
+{
+ return dm_btree_find_key(info, root, true, result_keys);
+}
+EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
+
+int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys)
+{
+ return dm_btree_find_key(info, root, false, result_keys);
+}
+EXPORT_SYMBOL_GPL(dm_btree_find_lowest_key);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * 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 int 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;
+}
+
+int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,
+ int (*fn)(void *context, uint64_t *keys, void *leaf),
+ void *context)
+{
+ BUG_ON(info->levels > 1);
+ return walk_node(info, root, fn, context);
+}
+EXPORT_SYMBOL_GPL(dm_btree_walk);
+
+/*----------------------------------------------------------------*/
+
+static void prefetch_values(struct dm_btree_cursor *c)
+{
+ unsigned int i, nr;
+ __le64 value_le;
+ struct cursor_node *n = c->nodes + c->depth - 1;
+ struct btree_node *bn = dm_block_data(n->b);
+ struct dm_block_manager *bm = dm_tm_get_bm(c->info->tm);
+
+ BUG_ON(c->info->value_type.size != sizeof(value_le));
+
+ nr = le32_to_cpu(bn->header.nr_entries);
+ for (i = 0; i < nr; i++) {
+ memcpy(&value_le, value_ptr(bn, i), sizeof(value_le));
+ dm_bm_prefetch(bm, le64_to_cpu(value_le));
+ }
+}
+
+static bool leaf_node(struct dm_btree_cursor *c)
+{
+ struct cursor_node *n = c->nodes + c->depth - 1;
+ struct btree_node *bn = dm_block_data(n->b);
+
+ return le32_to_cpu(bn->header.flags) & LEAF_NODE;
+}
+
+static int push_node(struct dm_btree_cursor *c, dm_block_t b)
+{
+ int r;
+ struct cursor_node *n = c->nodes + c->depth;
+
+ if (c->depth >= DM_BTREE_CURSOR_MAX_DEPTH - 1) {
+ DMERR("couldn't push cursor node, stack depth too high");
+ return -EINVAL;
+ }
+
+ r = bn_read_lock(c->info, b, &n->b);
+ if (r)
+ return r;
+
+ n->index = 0;
+ c->depth++;
+
+ if (c->prefetch_leaves || !leaf_node(c))
+ prefetch_values(c);
+
+ return 0;
+}
+
+static void pop_node(struct dm_btree_cursor *c)
+{
+ c->depth--;
+ unlock_block(c->info, c->nodes[c->depth].b);
+}
+
+static int inc_or_backtrack(struct dm_btree_cursor *c)
+{
+ struct cursor_node *n;
+ struct btree_node *bn;
+
+ for (;;) {
+ if (!c->depth)
+ return -ENODATA;
+
+ n = c->nodes + c->depth - 1;
+ bn = dm_block_data(n->b);
+
+ n->index++;
+ if (n->index < le32_to_cpu(bn->header.nr_entries))
+ break;
+
+ pop_node(c);
+ }
+
+ return 0;
+}
+
+static int find_leaf(struct dm_btree_cursor *c)
+{
+ int r = 0;
+ struct cursor_node *n;
+ struct btree_node *bn;
+ __le64 value_le;
+
+ for (;;) {
+ n = c->nodes + c->depth - 1;
+ bn = dm_block_data(n->b);
+
+ if (le32_to_cpu(bn->header.flags) & LEAF_NODE)
+ break;
+
+ memcpy(&value_le, value_ptr(bn, n->index), sizeof(value_le));
+ r = push_node(c, le64_to_cpu(value_le));
+ if (r) {
+ DMERR("push_node failed");
+ break;
+ }
+ }
+
+ if (!r && (le32_to_cpu(bn->header.nr_entries) == 0))
+ return -ENODATA;
+
+ return r;
+}
+
+int dm_btree_cursor_begin(struct dm_btree_info *info, dm_block_t root,
+ bool prefetch_leaves, struct dm_btree_cursor *c)
+{
+ int r;
+
+ c->info = info;
+ c->root = root;
+ c->depth = 0;
+ c->prefetch_leaves = prefetch_leaves;
+
+ r = push_node(c, root);
+ if (r)
+ return r;
+
+ return find_leaf(c);
+}
+EXPORT_SYMBOL_GPL(dm_btree_cursor_begin);
+
+void dm_btree_cursor_end(struct dm_btree_cursor *c)
+{
+ while (c->depth)
+ pop_node(c);
+}
+EXPORT_SYMBOL_GPL(dm_btree_cursor_end);
+
+int dm_btree_cursor_next(struct dm_btree_cursor *c)
+{
+ int r = inc_or_backtrack(c);
+ if (!r) {
+ r = find_leaf(c);
+ if (r)
+ DMERR("find_leaf failed");
+ }
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_cursor_next);
+
+int dm_btree_cursor_skip(struct dm_btree_cursor *c, uint32_t count)
+{
+ int r = 0;
+
+ while (count-- && !r)
+ r = dm_btree_cursor_next(c);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_btree_cursor_skip);
+
+int dm_btree_cursor_get_value(struct dm_btree_cursor *c, uint64_t *key, void *value_le)
+{
+ if (c->depth) {
+ struct cursor_node *n = c->nodes + c->depth - 1;
+ struct btree_node *bn = dm_block_data(n->b);
+
+ if (le32_to_cpu(bn->header.flags) & INTERNAL_NODE)
+ return -EINVAL;
+
+ *key = le64_to_cpu(*key_ptr(bn, n->index));
+ memcpy(value_le, value_ptr(bn, n->index), c->info->value_type.size);
+ return 0;
+
+ } else
+ return -ENODATA;
+}
+EXPORT_SYMBOL_GPL(dm_btree_cursor_get_value);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 22:13:44 +0000