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![Joe Thornber](/assets/img/avatar_default.png)
Corrupt metadata could trigger an out of bounds write. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1625 lines
38 KiB
C
1625 lines
38 KiB
C
/*
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* Copyright (C) 2011 Red Hat, Inc.
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*
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* This file is released under the GPL.
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*/
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#include "dm-btree-internal.h"
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#include "dm-space-map.h"
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#include "dm-transaction-manager.h"
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#include <linux/export.h>
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#include <linux/device-mapper.h>
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#define DM_MSG_PREFIX "btree"
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/*----------------------------------------------------------------
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* Array manipulation
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*--------------------------------------------------------------*/
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static void memcpy_disk(void *dest, const void *src, size_t len)
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__dm_written_to_disk(src)
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{
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memcpy(dest, src, len);
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__dm_unbless_for_disk(src);
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}
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static void array_insert(void *base, size_t elt_size, unsigned nr_elts,
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unsigned index, void *elt)
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__dm_written_to_disk(elt)
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{
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if (index < nr_elts)
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memmove(base + (elt_size * (index + 1)),
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base + (elt_size * index),
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(nr_elts - index) * elt_size);
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memcpy_disk(base + (elt_size * index), elt, elt_size);
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}
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/*----------------------------------------------------------------*/
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/* makes the assumption that no two keys are the same. */
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static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
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{
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int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
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while (hi - lo > 1) {
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int mid = lo + ((hi - lo) / 2);
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uint64_t mid_key = le64_to_cpu(n->keys[mid]);
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if (mid_key == key)
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return mid;
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if (mid_key < key)
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lo = mid;
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else
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hi = mid;
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}
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return want_hi ? hi : lo;
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}
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int lower_bound(struct btree_node *n, uint64_t key)
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{
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return bsearch(n, key, 0);
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}
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static int upper_bound(struct btree_node *n, uint64_t key)
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{
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return bsearch(n, key, 1);
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}
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void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
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struct dm_btree_value_type *vt)
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{
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uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
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if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
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dm_tm_with_runs(tm, value_ptr(n, 0), nr_entries, dm_tm_inc_range);
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else if (vt->inc)
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vt->inc(vt->context, value_ptr(n, 0), nr_entries);
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}
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static int insert_at(size_t value_size, struct btree_node *node, unsigned index,
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uint64_t key, void *value)
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__dm_written_to_disk(value)
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{
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uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
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uint32_t max_entries = le32_to_cpu(node->header.max_entries);
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__le64 key_le = cpu_to_le64(key);
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if (index > nr_entries ||
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index >= max_entries ||
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nr_entries >= max_entries) {
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DMERR("too many entries in btree node for insert");
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__dm_unbless_for_disk(value);
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return -ENOMEM;
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}
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__dm_bless_for_disk(&key_le);
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array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
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array_insert(value_base(node), value_size, nr_entries, index, value);
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node->header.nr_entries = cpu_to_le32(nr_entries + 1);
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return 0;
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}
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/*----------------------------------------------------------------*/
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/*
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* We want 3n entries (for some n). This works more nicely for repeated
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* insert remove loops than (2n + 1).
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*/
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static uint32_t calc_max_entries(size_t value_size, size_t block_size)
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{
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uint32_t total, n;
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size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */
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block_size -= sizeof(struct node_header);
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total = block_size / elt_size;
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n = total / 3; /* rounds down */
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return 3 * n;
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}
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int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
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{
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int r;
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struct dm_block *b;
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struct btree_node *n;
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size_t block_size;
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uint32_t max_entries;
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r = new_block(info, &b);
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if (r < 0)
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return r;
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block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
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max_entries = calc_max_entries(info->value_type.size, block_size);
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n = dm_block_data(b);
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memset(n, 0, block_size);
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n->header.flags = cpu_to_le32(LEAF_NODE);
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n->header.nr_entries = cpu_to_le32(0);
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n->header.max_entries = cpu_to_le32(max_entries);
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n->header.value_size = cpu_to_le32(info->value_type.size);
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*root = dm_block_location(b);
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unlock_block(info, b);
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return 0;
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}
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EXPORT_SYMBOL_GPL(dm_btree_empty);
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/*----------------------------------------------------------------*/
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/*
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* Deletion uses a recursive algorithm, since we have limited stack space
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* we explicitly manage our own stack on the heap.
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*/
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#define MAX_SPINE_DEPTH 64
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struct frame {
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struct dm_block *b;
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struct btree_node *n;
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unsigned level;
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unsigned nr_children;
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unsigned current_child;
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};
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struct del_stack {
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struct dm_btree_info *info;
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struct dm_transaction_manager *tm;
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int top;
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struct frame spine[MAX_SPINE_DEPTH];
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};
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static int top_frame(struct del_stack *s, struct frame **f)
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{
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if (s->top < 0) {
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DMERR("btree deletion stack empty");
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return -EINVAL;
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}
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*f = s->spine + s->top;
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return 0;
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}
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static int unprocessed_frames(struct del_stack *s)
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{
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return s->top >= 0;
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}
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static void prefetch_children(struct del_stack *s, struct frame *f)
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{
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unsigned i;
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struct dm_block_manager *bm = dm_tm_get_bm(s->tm);
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for (i = 0; i < f->nr_children; i++)
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dm_bm_prefetch(bm, value64(f->n, i));
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}
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static bool is_internal_level(struct dm_btree_info *info, struct frame *f)
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{
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return f->level < (info->levels - 1);
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}
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static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
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{
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int r;
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uint32_t ref_count;
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if (s->top >= MAX_SPINE_DEPTH - 1) {
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DMERR("btree deletion stack out of memory");
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return -ENOMEM;
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}
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r = dm_tm_ref(s->tm, b, &ref_count);
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if (r)
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return r;
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if (ref_count > 1)
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/*
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* This is a shared node, so we can just decrement it's
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* reference counter and leave the children.
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*/
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dm_tm_dec(s->tm, b);
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else {
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uint32_t flags;
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struct frame *f = s->spine + ++s->top;
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r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
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if (r) {
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s->top--;
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return r;
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}
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f->n = dm_block_data(f->b);
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f->level = level;
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f->nr_children = le32_to_cpu(f->n->header.nr_entries);
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f->current_child = 0;
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flags = le32_to_cpu(f->n->header.flags);
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if (flags & INTERNAL_NODE || is_internal_level(s->info, f))
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prefetch_children(s, f);
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}
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return 0;
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}
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static void pop_frame(struct del_stack *s)
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{
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struct frame *f = s->spine + s->top--;
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dm_tm_dec(s->tm, dm_block_location(f->b));
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dm_tm_unlock(s->tm, f->b);
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}
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static void unlock_all_frames(struct del_stack *s)
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{
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struct frame *f;
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while (unprocessed_frames(s)) {
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f = s->spine + s->top--;
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dm_tm_unlock(s->tm, f->b);
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}
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}
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int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
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{
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int r;
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struct del_stack *s;
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/*
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* dm_btree_del() is called via an ioctl, as such should be
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* considered an FS op. We can't recurse back into the FS, so we
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* allocate GFP_NOFS.
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*/
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s = kmalloc(sizeof(*s), GFP_NOFS);
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if (!s)
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return -ENOMEM;
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s->info = info;
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s->tm = info->tm;
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s->top = -1;
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r = push_frame(s, root, 0);
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if (r)
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goto out;
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while (unprocessed_frames(s)) {
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uint32_t flags;
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struct frame *f;
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dm_block_t b;
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r = top_frame(s, &f);
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if (r)
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goto out;
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if (f->current_child >= f->nr_children) {
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pop_frame(s);
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continue;
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}
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flags = le32_to_cpu(f->n->header.flags);
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if (flags & INTERNAL_NODE) {
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b = value64(f->n, f->current_child);
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f->current_child++;
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r = push_frame(s, b, f->level);
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if (r)
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goto out;
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} else if (is_internal_level(info, f)) {
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b = value64(f->n, f->current_child);
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f->current_child++;
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r = push_frame(s, b, f->level + 1);
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if (r)
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goto out;
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} else {
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if (info->value_type.dec)
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info->value_type.dec(info->value_type.context,
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value_ptr(f->n, 0), f->nr_children);
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pop_frame(s);
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}
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}
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out:
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if (r) {
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/* cleanup all frames of del_stack */
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unlock_all_frames(s);
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}
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kfree(s);
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return r;
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}
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EXPORT_SYMBOL_GPL(dm_btree_del);
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/*----------------------------------------------------------------*/
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static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
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int (*search_fn)(struct btree_node *, uint64_t),
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uint64_t *result_key, void *v, size_t value_size)
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{
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int i, r;
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uint32_t flags, nr_entries;
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do {
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r = ro_step(s, block);
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if (r < 0)
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return r;
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i = search_fn(ro_node(s), key);
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flags = le32_to_cpu(ro_node(s)->header.flags);
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nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
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if (i < 0 || i >= nr_entries)
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return -ENODATA;
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if (flags & INTERNAL_NODE)
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block = value64(ro_node(s), i);
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} while (!(flags & LEAF_NODE));
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*result_key = le64_to_cpu(ro_node(s)->keys[i]);
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if (v)
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memcpy(v, value_ptr(ro_node(s), i), value_size);
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return 0;
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}
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int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
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uint64_t *keys, void *value_le)
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{
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unsigned level, last_level = info->levels - 1;
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int r = -ENODATA;
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uint64_t rkey;
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__le64 internal_value_le;
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struct ro_spine spine;
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init_ro_spine(&spine, info);
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for (level = 0; level < info->levels; level++) {
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size_t size;
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void *value_p;
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if (level == last_level) {
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value_p = value_le;
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size = info->value_type.size;
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} else {
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value_p = &internal_value_le;
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size = sizeof(uint64_t);
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}
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r = btree_lookup_raw(&spine, root, keys[level],
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lower_bound, &rkey,
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value_p, size);
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if (!r) {
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if (rkey != keys[level]) {
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exit_ro_spine(&spine);
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return -ENODATA;
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}
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} else {
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exit_ro_spine(&spine);
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return r;
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}
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root = le64_to_cpu(internal_value_le);
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}
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exit_ro_spine(&spine);
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return r;
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}
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EXPORT_SYMBOL_GPL(dm_btree_lookup);
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static int dm_btree_lookup_next_single(struct dm_btree_info *info, dm_block_t root,
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uint64_t key, uint64_t *rkey, void *value_le)
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{
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int r, i;
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uint32_t flags, nr_entries;
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struct dm_block *node;
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struct btree_node *n;
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r = bn_read_lock(info, root, &node);
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if (r)
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return r;
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n = dm_block_data(node);
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flags = le32_to_cpu(n->header.flags);
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nr_entries = le32_to_cpu(n->header.nr_entries);
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|
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if (flags & INTERNAL_NODE) {
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i = lower_bound(n, key);
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if (i < 0) {
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/*
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* avoid early -ENODATA return when all entries are
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* higher than the search @key.
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*/
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i = 0;
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}
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if (i >= nr_entries) {
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r = -ENODATA;
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goto out;
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}
|
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r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
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if (r == -ENODATA && i < (nr_entries - 1)) {
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i++;
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r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
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}
|
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} else {
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i = upper_bound(n, key);
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if (i < 0 || i >= nr_entries) {
|
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r = -ENODATA;
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goto out;
|
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}
|
|
|
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*rkey = le64_to_cpu(n->keys[i]);
|
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memcpy(value_le, value_ptr(n, i), info->value_type.size);
|
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}
|
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out:
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dm_tm_unlock(info->tm, node);
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return r;
|
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}
|
|
|
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int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,
|
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uint64_t *keys, uint64_t *rkey, void *value_le)
|
|
{
|
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unsigned level;
|
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int r = -ENODATA;
|
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__le64 internal_value_le;
|
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struct ro_spine spine;
|
|
|
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init_ro_spine(&spine, info);
|
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for (level = 0; level < info->levels - 1u; level++) {
|
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r = btree_lookup_raw(&spine, root, keys[level],
|
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lower_bound, rkey,
|
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&internal_value_le, sizeof(uint64_t));
|
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if (r)
|
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goto out;
|
|
|
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if (*rkey != keys[level]) {
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r = -ENODATA;
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goto out;
|
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}
|
|
|
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root = le64_to_cpu(internal_value_le);
|
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}
|
|
|
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r = dm_btree_lookup_next_single(info, root, keys[level], rkey, value_le);
|
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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 dest_offset,
|
|
struct btree_node *src, unsigned src_offset,
|
|
unsigned count)
|
|
{
|
|
size_t value_size = le32_to_cpu(dest->header.value_size);
|
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memcpy(dest->keys + dest_offset, src->keys + src_offset, count * sizeof(uint64_t));
|
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memcpy(value_ptr(dest, dest_offset), value_ptr(src, src_offset), count * value_size);
|
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}
|
|
|
|
/*
|
|
* Moves entries from one region fo a btree node to another. The regions
|
|
* may overlap.
|
|
*/
|
|
static void move_entries(struct btree_node *dest, unsigned dest_offset,
|
|
struct btree_node *src, unsigned src_offset,
|
|
unsigned 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 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 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 nr_left = le32_to_cpu(left->header.nr_entries);
|
|
unsigned nr_right = le32_to_cpu(right->header.nr_entries);
|
|
unsigned total = nr_left + nr_right;
|
|
unsigned target_left = total / 2;
|
|
unsigned target_right = total - target_left;
|
|
|
|
if (nr_left < target_left) {
|
|
unsigned delta = target_left - nr_left;
|
|
copy_entries(left, nr_left, right, 0, delta);
|
|
shift_down(right, delta);
|
|
} else if (nr_left > target_left) {
|
|
unsigned 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 nr_left = le32_to_cpu(left->header.nr_entries);
|
|
unsigned nr_center = le32_to_cpu(center->header.nr_entries);
|
|
unsigned nr_right = le32_to_cpu(right->header.nr_entries);
|
|
unsigned 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 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 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 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 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 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 parent_index,
|
|
struct dm_btree_value_type *vt, uint64_t key)
|
|
{
|
|
int r;
|
|
unsigned 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 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 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 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 *space)
|
|
{
|
|
int r;
|
|
unsigned 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 parent_index, uint64_t key)
|
|
{
|
|
int r;
|
|
struct btree_node *parent = dm_block_data(shadow_parent(s));
|
|
unsigned nr_parent = le32_to_cpu(parent->header.nr_entries);
|
|
unsigned 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 *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 level, unsigned 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 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 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 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);
|