| /* |
| * 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 nr_elts, |
| unsigned 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); |
| } |
| |
| void inc_children(struct dm_transaction_manager *tm, struct btree_node *n, |
| struct dm_btree_value_type *vt) |
| { |
| unsigned i; |
| uint32_t nr_entries = le32_to_cpu(n->header.nr_entries); |
| |
| if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) |
| for (i = 0; i < nr_entries; i++) |
| dm_tm_inc(tm, value64(n, i)); |
| else if (vt->inc) |
| for (i = 0; i < nr_entries; i++) |
| vt->inc(vt->context, value_ptr(n, i)); |
| } |
| |
| static int insert_at(size_t value_size, struct btree_node *node, unsigned index, |
| uint64_t key, void *value) |
| __dm_written_to_disk(value) |
| { |
| uint32_t nr_entries = le32_to_cpu(node->header.nr_entries); |
| __le64 key_le = cpu_to_le64(key); |
| |
| if (index > nr_entries || |
| index >= le32_to_cpu(node->header.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); |
| return unlock_block(info, b); |
| } |
| 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 level; |
| unsigned nr_children; |
| unsigned 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 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 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); |
| } |
| |
| int dm_btree_del(struct dm_btree_info *info, dm_block_t root) |
| { |
| int r; |
| struct del_stack *s; |
| |
| s = kmalloc(sizeof(*s), GFP_NOIO); |
| 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) { |
| unsigned i; |
| |
| for (i = 0; i < f->nr_children; i++) |
| info->value_type.dec(info->value_type.context, |
| value_ptr(f->n, i)); |
| } |
| pop_frame(s); |
| } |
| } |
| |
| out: |
| 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]); |
| 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 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); |
| |
| /* |
| * 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; |
| } |
| |
| 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; |
| } |
| |
| 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, need_insert; |
| unsigned 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; |
| |
| le64_type.context = NULL; |
| le64_type.size = sizeof(__le64); |
| le64_type.inc = NULL; |
| le64_type.dec = NULL; |
| le64_type.equal = NULL; |
| |
| 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)); |
| need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) || |
| (le64_to_cpu(n->keys[index]) != keys[level])); |
| |
| if (need_insert) { |
| 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)); |
| need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) || |
| (le64_to_cpu(n->keys[index]) != keys[level])); |
| |
| if (need_insert) { |
| 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)); |
| } |
| 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) |
| block = value64(ro_node(s), i); |
| |
| } 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 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); |