--- /dev/null
+/*
+ * Code for working with individual keys, and sorted sets of keys with in a
+ * btree node
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
+
+#include "util.h"
+#include "bset.h"
+
+#include <linux/console.h>
+#include <linux/random.h>
+#include <linux/prefetch.h>
+
+#ifdef CONFIG_BCACHE_DEBUG
+
+void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned set)
+{
+ struct bkey *k, *next;
+
+ for (k = i->start; k < bset_bkey_last(i); k = next) {
+ next = bkey_next(k);
+
+ printk(KERN_ERR "block %u key %u/%u: ", set,
+ (unsigned) ((u64 *) k - i->d), i->keys);
+
+ if (b->ops->key_dump)
+ b->ops->key_dump(b, k);
+ else
+ printk("%llu:%llu\n", KEY_INODE(k), KEY_OFFSET(k));
+
+ if (next < bset_bkey_last(i) &&
+ bkey_cmp(k, b->ops->is_extents ?
+ &START_KEY(next) : next) > 0)
+ printk(KERN_ERR "Key skipped backwards\n");
+ }
+}
+
+void bch_dump_bucket(struct btree_keys *b)
+{
+ unsigned i;
+
+ console_lock();
+ for (i = 0; i <= b->nsets; i++)
+ bch_dump_bset(b, b->set[i].data,
+ bset_sector_offset(b, b->set[i].data));
+ console_unlock();
+}
+
+int __bch_count_data(struct btree_keys *b)
+{
+ unsigned ret = 0;
+ struct btree_iter iter;
+ struct bkey *k;
+
+ if (b->ops->is_extents)
+ for_each_key(b, k, &iter)
+ ret += KEY_SIZE(k);
+ return ret;
+}
+
+void __bch_check_keys(struct btree_keys *b, const char *fmt, ...)
+{
+ va_list args;
+ struct bkey *k, *p = NULL;
+ struct btree_iter iter;
+ const char *err;
+
+ for_each_key(b, k, &iter) {
+ if (b->ops->is_extents) {
+ err = "Keys out of order";
+ if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
+ goto bug;
+
+ if (bch_ptr_invalid(b, k))
+ continue;
+
+ err = "Overlapping keys";
+ if (p && bkey_cmp(p, &START_KEY(k)) > 0)
+ goto bug;
+ } else {
+ if (bch_ptr_bad(b, k))
+ continue;
+
+ err = "Duplicate keys";
+ if (p && !bkey_cmp(p, k))
+ goto bug;
+ }
+ p = k;
+ }
+#if 0
+ err = "Key larger than btree node key";
+ if (p && bkey_cmp(p, &b->key) > 0)
+ goto bug;
+#endif
+ return;
+bug:
+ bch_dump_bucket(b);
+
+ va_start(args, fmt);
+ vprintk(fmt, args);
+ va_end(args);
+
+ panic("bch_check_keys error: %s:\n", err);
+}
+
+static void bch_btree_iter_next_check(struct btree_iter *iter)
+{
+ struct bkey *k = iter->data->k, *next = bkey_next(k);
+
+ if (next < iter->data->end &&
+ bkey_cmp(k, iter->b->ops->is_extents ?
+ &START_KEY(next) : next) > 0) {
+ bch_dump_bucket(iter->b);
+ panic("Key skipped backwards\n");
+ }
+}
+
+#else
+
+static inline void bch_btree_iter_next_check(struct btree_iter *iter) {}
+
+#endif
+
+/* Keylists */
+
+int __bch_keylist_realloc(struct keylist *l, unsigned u64s)
+{
+ size_t oldsize = bch_keylist_nkeys(l);
+ size_t newsize = oldsize + u64s;
+ uint64_t *old_keys = l->keys_p == l->inline_keys ? NULL : l->keys_p;
+ uint64_t *new_keys;
+
+ newsize = roundup_pow_of_two(newsize);
+
+ if (newsize <= KEYLIST_INLINE ||
+ roundup_pow_of_two(oldsize) == newsize)
+ return 0;
+
+ new_keys = krealloc(old_keys, sizeof(uint64_t) * newsize, GFP_NOIO);
+
+ if (!new_keys)
+ return -ENOMEM;
+
+ if (!old_keys)
+ memcpy(new_keys, l->inline_keys, sizeof(uint64_t) * oldsize);
+
+ l->keys_p = new_keys;
+ l->top_p = new_keys + oldsize;
+
+ return 0;
+}
+
+struct bkey *bch_keylist_pop(struct keylist *l)
+{
+ struct bkey *k = l->keys;
+
+ if (k == l->top)
+ return NULL;
+
+ while (bkey_next(k) != l->top)
+ k = bkey_next(k);
+
+ return l->top = k;
+}
+
+void bch_keylist_pop_front(struct keylist *l)
+{
+ l->top_p -= bkey_u64s(l->keys);
+
+ memmove(l->keys,
+ bkey_next(l->keys),
+ bch_keylist_bytes(l));
+}
+
+/* Key/pointer manipulation */
+
+void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
+ unsigned i)
+{
+ BUG_ON(i > KEY_PTRS(src));
+
+ /* Only copy the header, key, and one pointer. */
+ memcpy(dest, src, 2 * sizeof(uint64_t));
+ dest->ptr[0] = src->ptr[i];
+ SET_KEY_PTRS(dest, 1);
+ /* We didn't copy the checksum so clear that bit. */
+ SET_KEY_CSUM(dest, 0);
+}
+
+bool __bch_cut_front(const struct bkey *where, struct bkey *k)
+{
+ unsigned i, len = 0;
+
+ if (bkey_cmp(where, &START_KEY(k)) <= 0)
+ return false;
+
+ if (bkey_cmp(where, k) < 0)
+ len = KEY_OFFSET(k) - KEY_OFFSET(where);
+ else
+ bkey_copy_key(k, where);
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
+
+ BUG_ON(len > KEY_SIZE(k));
+ SET_KEY_SIZE(k, len);
+ return true;
+}
+
+bool __bch_cut_back(const struct bkey *where, struct bkey *k)
+{
+ unsigned len = 0;
+
+ if (bkey_cmp(where, k) >= 0)
+ return false;
+
+ BUG_ON(KEY_INODE(where) != KEY_INODE(k));
+
+ if (bkey_cmp(where, &START_KEY(k)) > 0)
+ len = KEY_OFFSET(where) - KEY_START(k);
+
+ bkey_copy_key(k, where);
+
+ BUG_ON(len > KEY_SIZE(k));
+ SET_KEY_SIZE(k, len);
+ return true;
+}
+
+/* Auxiliary search trees */
+
+/* 32 bits total: */
+#define BKEY_MID_BITS 3
+#define BKEY_EXPONENT_BITS 7
+#define BKEY_MANTISSA_BITS (32 - BKEY_MID_BITS - BKEY_EXPONENT_BITS)
+#define BKEY_MANTISSA_MASK ((1 << BKEY_MANTISSA_BITS) - 1)
+
+struct bkey_float {
+ unsigned exponent:BKEY_EXPONENT_BITS;
+ unsigned m:BKEY_MID_BITS;
+ unsigned mantissa:BKEY_MANTISSA_BITS;
+} __packed;
+
+/*
+ * BSET_CACHELINE was originally intended to match the hardware cacheline size -
+ * it used to be 64, but I realized the lookup code would touch slightly less
+ * memory if it was 128.
+ *
+ * It definites the number of bytes (in struct bset) per struct bkey_float in
+ * the auxiliar search tree - when we're done searching the bset_float tree we
+ * have this many bytes left that we do a linear search over.
+ *
+ * Since (after level 5) every level of the bset_tree is on a new cacheline,
+ * we're touching one fewer cacheline in the bset tree in exchange for one more
+ * cacheline in the linear search - but the linear search might stop before it
+ * gets to the second cacheline.
+ */
+
+#define BSET_CACHELINE 128
+
+/* Space required for the btree node keys */
+static inline size_t btree_keys_bytes(struct btree_keys *b)
+{
+ return PAGE_SIZE << b->page_order;
+}
+
+static inline size_t btree_keys_cachelines(struct btree_keys *b)
+{
+ return btree_keys_bytes(b) / BSET_CACHELINE;
+}
+
+/* Space required for the auxiliary search trees */
+static inline size_t bset_tree_bytes(struct btree_keys *b)
+{
+ return btree_keys_cachelines(b) * sizeof(struct bkey_float);
+}
+
+/* Space required for the prev pointers */
+static inline size_t bset_prev_bytes(struct btree_keys *b)
+{
+ return btree_keys_cachelines(b) * sizeof(uint8_t);
+}
+
+/* Memory allocation */
+
+void bch_btree_keys_free(struct btree_keys *b)
+{
+ struct bset_tree *t = b->set;
+
+ if (bset_prev_bytes(b) < PAGE_SIZE)
+ kfree(t->prev);
+ else
+ free_pages((unsigned long) t->prev,
+ get_order(bset_prev_bytes(b)));
+
+ if (bset_tree_bytes(b) < PAGE_SIZE)
+ kfree(t->tree);
+ else
+ free_pages((unsigned long) t->tree,
+ get_order(bset_tree_bytes(b)));
+
+ free_pages((unsigned long) t->data, b->page_order);
+
+ t->prev = NULL;
+ t->tree = NULL;
+ t->data = NULL;
+}
+EXPORT_SYMBOL(bch_btree_keys_free);
+
+int bch_btree_keys_alloc(struct btree_keys *b, unsigned page_order, gfp_t gfp)
+{
+ struct bset_tree *t = b->set;
+
+ BUG_ON(t->data);
+
+ b->page_order = page_order;
+
+ t->data = (void *) __get_free_pages(gfp, b->page_order);
+ if (!t->data)
+ goto err;
+
+ t->tree = bset_tree_bytes(b) < PAGE_SIZE
+ ? kmalloc(bset_tree_bytes(b), gfp)
+ : (void *) __get_free_pages(gfp, get_order(bset_tree_bytes(b)));
+ if (!t->tree)
+ goto err;
+
+ t->prev = bset_prev_bytes(b) < PAGE_SIZE
+ ? kmalloc(bset_prev_bytes(b), gfp)
+ : (void *) __get_free_pages(gfp, get_order(bset_prev_bytes(b)));
+ if (!t->prev)
+ goto err;
+
+ return 0;
+err:
+ bch_btree_keys_free(b);
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(bch_btree_keys_alloc);
+
+void bch_btree_keys_init(struct btree_keys *b, const struct btree_keys_ops *ops,
+ bool *expensive_debug_checks)
+{
+ unsigned i;
+
+ b->ops = ops;
+ b->expensive_debug_checks = expensive_debug_checks;
+ b->nsets = 0;
+ b->last_set_unwritten = 0;
+
+ /* XXX: shouldn't be needed */
+ for (i = 0; i < MAX_BSETS; i++)
+ b->set[i].size = 0;
+ /*
+ * Second loop starts at 1 because b->keys[0]->data is the memory we
+ * allocated
+ */
+ for (i = 1; i < MAX_BSETS; i++)
+ b->set[i].data = NULL;
+}
+EXPORT_SYMBOL(bch_btree_keys_init);
+
+/* Binary tree stuff for auxiliary search trees */
+
+static unsigned inorder_next(unsigned j, unsigned size)
+{
+ if (j * 2 + 1 < size) {
+ j = j * 2 + 1;
+
+ while (j * 2 < size)
+ j *= 2;
+ } else
+ j >>= ffz(j) + 1;
+
+ return j;
+}
+
+static unsigned inorder_prev(unsigned j, unsigned size)
+{
+ if (j * 2 < size) {
+ j = j * 2;
+
+ while (j * 2 + 1 < size)
+ j = j * 2 + 1;
+ } else
+ j >>= ffs(j);
+
+ return j;
+}
+
+/* I have no idea why this code works... and I'm the one who wrote it
+ *
+ * However, I do know what it does:
+ * Given a binary tree constructed in an array (i.e. how you normally implement
+ * a heap), it converts a node in the tree - referenced by array index - to the
+ * index it would have if you did an inorder traversal.
+ *
+ * Also tested for every j, size up to size somewhere around 6 million.
+ *
+ * The binary tree starts at array index 1, not 0
+ * extra is a function of size:
+ * extra = (size - rounddown_pow_of_two(size - 1)) << 1;
+ */
+static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra)
+{
+ unsigned b = fls(j);
+ unsigned shift = fls(size - 1) - b;
+
+ j ^= 1U << (b - 1);
+ j <<= 1;
+ j |= 1;
+ j <<= shift;
+
+ if (j > extra)
+ j -= (j - extra) >> 1;
+
+ return j;
+}
+
+static unsigned to_inorder(unsigned j, struct bset_tree *t)
+{
+ return __to_inorder(j, t->size, t->extra);
+}
+
+static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra)
+{
+ unsigned shift;
+
+ if (j > extra)
+ j += j - extra;
+
+ shift = ffs(j);
+
+ j >>= shift;
+ j |= roundup_pow_of_two(size) >> shift;
+
+ return j;
+}
+
+static unsigned inorder_to_tree(unsigned j, struct bset_tree *t)
+{
+ return __inorder_to_tree(j, t->size, t->extra);
+}
+
+#if 0
+void inorder_test(void)
+{
+ unsigned long done = 0;
+ ktime_t start = ktime_get();
+
+ for (unsigned size = 2;
+ size < 65536000;
+ size++) {
+ unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1;
+ unsigned i = 1, j = rounddown_pow_of_two(size - 1);
+
+ if (!(size % 4096))
+ printk(KERN_NOTICE "loop %u, %llu per us\n", size,
+ done / ktime_us_delta(ktime_get(), start));
+
+ while (1) {
+ if (__inorder_to_tree(i, size, extra) != j)
+ panic("size %10u j %10u i %10u", size, j, i);
+
+ if (__to_inorder(j, size, extra) != i)
+ panic("size %10u j %10u i %10u", size, j, i);
+
+ if (j == rounddown_pow_of_two(size) - 1)
+ break;
+
+ BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
+
+ j = inorder_next(j, size);
+ i++;
+ }
+
+ done += size - 1;
+ }
+}
+#endif
+
+/*
+ * Cacheline/offset <-> bkey pointer arithmetic:
+ *
+ * t->tree is a binary search tree in an array; each node corresponds to a key
+ * in one cacheline in t->set (BSET_CACHELINE bytes).
+ *
+ * This means we don't have to store the full index of the key that a node in
+ * the binary tree points to; to_inorder() gives us the cacheline, and then
+ * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
+ *
+ * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
+ * make this work.
+ *
+ * To construct the bfloat for an arbitrary key we need to know what the key
+ * immediately preceding it is: we have to check if the two keys differ in the
+ * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
+ * of the previous key so we can walk backwards to it from t->tree[j]'s key.
+ */
+
+static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline,
+ unsigned offset)
+{
+ return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
+}
+
+static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
+{
+ return ((void *) k - (void *) t->data) / BSET_CACHELINE;
+}
+
+static unsigned bkey_to_cacheline_offset(struct bset_tree *t,
+ unsigned cacheline,
+ struct bkey *k)
+{
+ return (u64 *) k - (u64 *) cacheline_to_bkey(t, cacheline, 0);
+}
+
+static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j)
+{
+ return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
+}
+
+static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j)
+{
+ return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
+}
+
+/*
+ * For the write set - the one we're currently inserting keys into - we don't
+ * maintain a full search tree, we just keep a simple lookup table in t->prev.
+ */
+static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
+{
+ return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
+}
+
+static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
+{
+ low >>= shift;
+ low |= (high << 1) << (63U - shift);
+ return low;
+}
+
+static inline unsigned bfloat_mantissa(const struct bkey *k,
+ struct bkey_float *f)
+{
+ const uint64_t *p = &k->low - (f->exponent >> 6);
+ return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
+}
+
+static void make_bfloat(struct bset_tree *t, unsigned j)
+{
+ struct bkey_float *f = &t->tree[j];
+ struct bkey *m = tree_to_bkey(t, j);
+ struct bkey *p = tree_to_prev_bkey(t, j);
+
+ struct bkey *l = is_power_of_2(j)
+ ? t->data->start
+ : tree_to_prev_bkey(t, j >> ffs(j));
+
+ struct bkey *r = is_power_of_2(j + 1)
+ ? bset_bkey_idx(t->data, t->data->keys - bkey_u64s(&t->end))
+ : tree_to_bkey(t, j >> (ffz(j) + 1));
+
+ BUG_ON(m < l || m > r);
+ BUG_ON(bkey_next(p) != m);
+
+ if (KEY_INODE(l) != KEY_INODE(r))
+ f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64;
+ else
+ f->exponent = fls64(r->low ^ l->low);
+
+ f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0);
+
+ /*
+ * Setting f->exponent = 127 flags this node as failed, and causes the
+ * lookup code to fall back to comparing against the original key.
+ */
+
+ if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f))
+ f->mantissa = bfloat_mantissa(m, f) - 1;
+ else
+ f->exponent = 127;
+}
+
+static void bset_alloc_tree(struct btree_keys *b, struct bset_tree *t)
+{
+ if (t != b->set) {
+ unsigned j = roundup(t[-1].size,
+ 64 / sizeof(struct bkey_float));
+
+ t->tree = t[-1].tree + j;
+ t->prev = t[-1].prev + j;
+ }
+
+ while (t < b->set + MAX_BSETS)
+ t++->size = 0;
+}
+
+static void bch_bset_build_unwritten_tree(struct btree_keys *b)
+{
+ struct bset_tree *t = bset_tree_last(b);
+
+ BUG_ON(b->last_set_unwritten);
+ b->last_set_unwritten = 1;
+
+ bset_alloc_tree(b, t);
+
+ if (t->tree != b->set->tree + btree_keys_cachelines(b)) {
+ t->prev[0] = bkey_to_cacheline_offset(t, 0, t->data->start);
+ t->size = 1;
+ }
+}
+
+void bch_bset_init_next(struct btree_keys *b, struct bset *i, uint64_t magic)
+{
+ if (i != b->set->data) {
+ b->set[++b->nsets].data = i;
+ i->seq = b->set->data->seq;
+ } else
+ get_random_bytes(&i->seq, sizeof(uint64_t));
+
+ i->magic = magic;
+ i->version = 0;
+ i->keys = 0;
+
+ bch_bset_build_unwritten_tree(b);
+}
+EXPORT_SYMBOL(bch_bset_init_next);
+
+void bch_bset_build_written_tree(struct btree_keys *b)
+{
+ struct bset_tree *t = bset_tree_last(b);
+ struct bkey *prev = NULL, *k = t->data->start;
+ unsigned j, cacheline = 1;
+
+ b->last_set_unwritten = 0;
+
+ bset_alloc_tree(b, t);
+
+ t->size = min_t(unsigned,
+ bkey_to_cacheline(t, bset_bkey_last(t->data)),
+ b->set->tree + btree_keys_cachelines(b) - t->tree);
+
+ if (t->size < 2) {
+ t->size = 0;
+ return;
+ }
+
+ t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
+
+ /* First we figure out where the first key in each cacheline is */
+ for (j = inorder_next(0, t->size);
+ j;
+ j = inorder_next(j, t->size)) {
+ while (bkey_to_cacheline(t, k) < cacheline)
+ prev = k, k = bkey_next(k);
+
+ t->prev[j] = bkey_u64s(prev);
+ t->tree[j].m = bkey_to_cacheline_offset(t, cacheline++, k);
+ }
+
+ while (bkey_next(k) != bset_bkey_last(t->data))
+ k = bkey_next(k);
+
+ t->end = *k;
+
+ /* Then we build the tree */
+ for (j = inorder_next(0, t->size);
+ j;
+ j = inorder_next(j, t->size))
+ make_bfloat(t, j);
+}
+EXPORT_SYMBOL(bch_bset_build_written_tree);
+
+/* Insert */
+
+void bch_bset_fix_invalidated_key(struct btree_keys *b, struct bkey *k)
+{
+ struct bset_tree *t;
+ unsigned inorder, j = 1;
+
+ for (t = b->set; t <= bset_tree_last(b); t++)
+ if (k < bset_bkey_last(t->data))
+ goto found_set;
+
+ BUG();
+found_set:
+ if (!t->size || !bset_written(b, t))
+ return;
+
+ inorder = bkey_to_cacheline(t, k);
+
+ if (k == t->data->start)
+ goto fix_left;
+
+ if (bkey_next(k) == bset_bkey_last(t->data)) {
+ t->end = *k;
+ goto fix_right;
+ }
+
+ j = inorder_to_tree(inorder, t);
+
+ if (j &&
+ j < t->size &&
+ k == tree_to_bkey(t, j))
+fix_left: do {
+ make_bfloat(t, j);
+ j = j * 2;
+ } while (j < t->size);
+
+ j = inorder_to_tree(inorder + 1, t);
+
+ if (j &&
+ j < t->size &&
+ k == tree_to_prev_bkey(t, j))
+fix_right: do {
+ make_bfloat(t, j);
+ j = j * 2 + 1;
+ } while (j < t->size);
+}
+EXPORT_SYMBOL(bch_bset_fix_invalidated_key);
+
+static void bch_bset_fix_lookup_table(struct btree_keys *b,
+ struct bset_tree *t,
+ struct bkey *k)
+{
+ unsigned shift = bkey_u64s(k);
+ unsigned j = bkey_to_cacheline(t, k);
+
+ /* We're getting called from btree_split() or btree_gc, just bail out */
+ if (!t->size)
+ return;
+
+ /* k is the key we just inserted; we need to find the entry in the
+ * lookup table for the first key that is strictly greater than k:
+ * it's either k's cacheline or the next one
+ */
+ while (j < t->size &&
+ table_to_bkey(t, j) <= k)
+ j++;
+
+ /* Adjust all the lookup table entries, and find a new key for any that
+ * have gotten too big
+ */
+ for (; j < t->size; j++) {
+ t->prev[j] += shift;
+
+ if (t->prev[j] > 7) {
+ k = table_to_bkey(t, j - 1);
+
+ while (k < cacheline_to_bkey(t, j, 0))
+ k = bkey_next(k);
+
+ t->prev[j] = bkey_to_cacheline_offset(t, j, k);
+ }
+ }
+
+ if (t->size == b->set->tree + btree_keys_cachelines(b) - t->tree)
+ return;
+
+ /* Possibly add a new entry to the end of the lookup table */
+
+ for (k = table_to_bkey(t, t->size - 1);
+ k != bset_bkey_last(t->data);
+ k = bkey_next(k))
+ if (t->size == bkey_to_cacheline(t, k)) {
+ t->prev[t->size] = bkey_to_cacheline_offset(t, t->size, k);
+ t->size++;
+ }
+}
+
+/*
+ * Tries to merge l and r: l should be lower than r
+ * Returns true if we were able to merge. If we did merge, l will be the merged
+ * key, r will be untouched.
+ */
+bool bch_bkey_try_merge(struct btree_keys *b, struct bkey *l, struct bkey *r)
+{
+ if (!b->ops->key_merge)
+ return false;
+
+ /*
+ * Generic header checks
+ * Assumes left and right are in order
+ * Left and right must be exactly aligned
+ */
+ if (!bch_bkey_equal_header(l, r) ||
+ bkey_cmp(l, &START_KEY(r)))
+ return false;
+
+ return b->ops->key_merge(b, l, r);
+}
+EXPORT_SYMBOL(bch_bkey_try_merge);
+
+void bch_bset_insert(struct btree_keys *b, struct bkey *where,
+ struct bkey *insert)
+{
+ struct bset_tree *t = bset_tree_last(b);
+
+ BUG_ON(!b->last_set_unwritten);
+ BUG_ON(bset_byte_offset(b, t->data) +
+ __set_bytes(t->data, t->data->keys + bkey_u64s(insert)) >
+ PAGE_SIZE << b->page_order);
+
+ memmove((uint64_t *) where + bkey_u64s(insert),
+ where,
+ (void *) bset_bkey_last(t->data) - (void *) where);
+
+ t->data->keys += bkey_u64s(insert);
+ bkey_copy(where, insert);
+ bch_bset_fix_lookup_table(b, t, where);
+}
+EXPORT_SYMBOL(bch_bset_insert);
+
+unsigned bch_btree_insert_key(struct btree_keys *b, struct bkey *k,
+ struct bkey *replace_key)
+{
+ unsigned status = BTREE_INSERT_STATUS_NO_INSERT;
+ struct bset *i = bset_tree_last(b)->data;
+ struct bkey *m, *prev = NULL;
+ struct btree_iter iter;
+
+ BUG_ON(b->ops->is_extents && !KEY_SIZE(k));
+
+ m = bch_btree_iter_init(b, &iter, b->ops->is_extents
+ ? PRECEDING_KEY(&START_KEY(k))
+ : PRECEDING_KEY(k));
+
+ if (b->ops->insert_fixup(b, k, &iter, replace_key))
+ return status;
+
+ status = BTREE_INSERT_STATUS_INSERT;
+
+ while (m != bset_bkey_last(i) &&
+ bkey_cmp(k, b->ops->is_extents ? &START_KEY(m) : m) > 0)
+ prev = m, m = bkey_next(m);
+
+ /* prev is in the tree, if we merge we're done */
+ status = BTREE_INSERT_STATUS_BACK_MERGE;
+ if (prev &&
+ bch_bkey_try_merge(b, prev, k))
+ goto merged;
+#if 0
+ status = BTREE_INSERT_STATUS_OVERWROTE;
+ if (m != bset_bkey_last(i) &&
+ KEY_PTRS(m) == KEY_PTRS(k) && !KEY_SIZE(m))
+ goto copy;
+#endif
+ status = BTREE_INSERT_STATUS_FRONT_MERGE;
+ if (m != bset_bkey_last(i) &&
+ bch_bkey_try_merge(b, k, m))
+ goto copy;
+
+ bch_bset_insert(b, m, k);
+copy: bkey_copy(m, k);
+merged:
+ return status;
+}
+EXPORT_SYMBOL(bch_btree_insert_key);
+
+/* Lookup */
+
+struct bset_search_iter {
+ struct bkey *l, *r;
+};
+
+static struct bset_search_iter bset_search_write_set(struct bset_tree *t,
+ const struct bkey *search)
+{
+ unsigned li = 0, ri = t->size;
+
+ while (li + 1 != ri) {
+ unsigned m = (li + ri) >> 1;
+
+ if (bkey_cmp(table_to_bkey(t, m), search) > 0)
+ ri = m;
+ else
+ li = m;
+ }
+
+ return (struct bset_search_iter) {
+ table_to_bkey(t, li),
+ ri < t->size ? table_to_bkey(t, ri) : bset_bkey_last(t->data)
+ };
+}
+
+static struct bset_search_iter bset_search_tree(struct bset_tree *t,
+ const struct bkey *search)
+{
+ struct bkey *l, *r;
+ struct bkey_float *f;
+ unsigned inorder, j, n = 1;
+
+ do {
+ unsigned p = n << 4;
+ p &= ((int) (p - t->size)) >> 31;
+
+ prefetch(&t->tree[p]);
+
+ j = n;
+ f = &t->tree[j];
+
+ /*
+ * n = (f->mantissa > bfloat_mantissa())
+ * ? j * 2
+ * : j * 2 + 1;
+ *
+ * We need to subtract 1 from f->mantissa for the sign bit trick
+ * to work - that's done in make_bfloat()
+ */
+ if (likely(f->exponent != 127))
+ n = j * 2 + (((unsigned)
+ (f->mantissa -
+ bfloat_mantissa(search, f))) >> 31);
+ else
+ n = (bkey_cmp(tree_to_bkey(t, j), search) > 0)
+ ? j * 2
+ : j * 2 + 1;
+ } while (n < t->size);
+
+ inorder = to_inorder(j, t);
+
+ /*
+ * n would have been the node we recursed to - the low bit tells us if
+ * we recursed left or recursed right.
+ */
+ if (n & 1) {
+ l = cacheline_to_bkey(t, inorder, f->m);
+
+ if (++inorder != t->size) {
+ f = &t->tree[inorder_next(j, t->size)];
+ r = cacheline_to_bkey(t, inorder, f->m);
+ } else
+ r = bset_bkey_last(t->data);
+ } else {
+ r = cacheline_to_bkey(t, inorder, f->m);
+
+ if (--inorder) {
+ f = &t->tree[inorder_prev(j, t->size)];
+ l = cacheline_to_bkey(t, inorder, f->m);
+ } else
+ l = t->data->start;
+ }
+
+ return (struct bset_search_iter) {l, r};
+}
+
+struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t,
+ const struct bkey *search)
+{
+ struct bset_search_iter i;
+
+ /*
+ * First, we search for a cacheline, then lastly we do a linear search
+ * within that cacheline.
+ *
+ * To search for the cacheline, there's three different possibilities:
+ * * The set is too small to have a search tree, so we just do a linear
+ * search over the whole set.
+ * * The set is the one we're currently inserting into; keeping a full
+ * auxiliary search tree up to date would be too expensive, so we
+ * use a much simpler lookup table to do a binary search -
+ * bset_search_write_set().
+ * * Or we use the auxiliary search tree we constructed earlier -
+ * bset_search_tree()
+ */
+
+ if (unlikely(!t->size)) {
+ i.l = t->data->start;
+ i.r = bset_bkey_last(t->data);
+ } else if (bset_written(b, t)) {
+ /*
+ * Each node in the auxiliary search tree covers a certain range
+ * of bits, and keys above and below the set it covers might
+ * differ outside those bits - so we have to special case the
+ * start and end - handle that here:
+ */
+
+ if (unlikely(bkey_cmp(search, &t->end) >= 0))
+ return bset_bkey_last(t->data);
+
+ if (unlikely(bkey_cmp(search, t->data->start) < 0))
+ return t->data->start;
+
+ i = bset_search_tree(t, search);
+ } else {
+ BUG_ON(!b->nsets &&
+ t->size < bkey_to_cacheline(t, bset_bkey_last(t->data)));
+
+ i = bset_search_write_set(t, search);
+ }
+
+ if (btree_keys_expensive_checks(b)) {
+ BUG_ON(bset_written(b, t) &&
+ i.l != t->data->start &&
+ bkey_cmp(tree_to_prev_bkey(t,
+ inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
+ search) > 0);
+
+ BUG_ON(i.r != bset_bkey_last(t->data) &&
+ bkey_cmp(i.r, search) <= 0);
+ }
+
+ while (likely(i.l != i.r) &&
+ bkey_cmp(i.l, search) <= 0)
+ i.l = bkey_next(i.l);
+
+ return i.l;
+}
+EXPORT_SYMBOL(__bch_bset_search);
+
+/* Btree iterator */
+
+typedef bool (btree_iter_cmp_fn)(struct btree_iter_set,
+ struct btree_iter_set);
+
+static inline bool btree_iter_cmp(struct btree_iter_set l,
+ struct btree_iter_set r)
+{
+ return bkey_cmp(l.k, r.k) > 0;
+}
+
+static inline bool btree_iter_end(struct btree_iter *iter)
+{
+ return !iter->used;
+}
+
+void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
+ struct bkey *end)
+{
+ if (k != end)
+ BUG_ON(!heap_add(iter,
+ ((struct btree_iter_set) { k, end }),
+ btree_iter_cmp));
+}
+
+static struct bkey *__bch_btree_iter_init(struct btree_keys *b,
+ struct btree_iter *iter,
+ struct bkey *search,
+ struct bset_tree *start)
+{
+ struct bkey *ret = NULL;
+ iter->size = ARRAY_SIZE(iter->data);
+ iter->used = 0;
+
+#ifdef CONFIG_BCACHE_DEBUG
+ iter->b = b;
+#endif
+
+ for (; start <= bset_tree_last(b); start++) {
+ ret = bch_bset_search(b, start, search);
+ bch_btree_iter_push(iter, ret, bset_bkey_last(start->data));
+ }
+
+ return ret;
+}
+
+struct bkey *bch_btree_iter_init(struct btree_keys *b,
+ struct btree_iter *iter,
+ struct bkey *search)
+{
+ return __bch_btree_iter_init(b, iter, search, b->set);
+}
+EXPORT_SYMBOL(bch_btree_iter_init);
+
+static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
+ btree_iter_cmp_fn *cmp)
+{
+ struct btree_iter_set unused;
+ struct bkey *ret = NULL;
+
+ if (!btree_iter_end(iter)) {
+ bch_btree_iter_next_check(iter);
+
+ ret = iter->data->k;
+ iter->data->k = bkey_next(iter->data->k);
+
+ if (iter->data->k > iter->data->end) {
+ WARN_ONCE(1, "bset was corrupt!\n");
+ iter->data->k = iter->data->end;
+ }
+
+ if (iter->data->k == iter->data->end)
+ heap_pop(iter, unused, cmp);
+ else
+ heap_sift(iter, 0, cmp);
+ }
+
+ return ret;
+}
+
+struct bkey *bch_btree_iter_next(struct btree_iter *iter)
+{
+ return __bch_btree_iter_next(iter, btree_iter_cmp);
+
+}
+EXPORT_SYMBOL(bch_btree_iter_next);
+
+struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
+ struct btree_keys *b, ptr_filter_fn fn)
+{
+ struct bkey *ret;
+
+ do {
+ ret = bch_btree_iter_next(iter);
+ } while (ret && fn(b, ret));
+
+ return ret;
+}
+
+/* Mergesort */
+
+void bch_bset_sort_state_free(struct bset_sort_state *state)
+{
+ if (state->pool)
+ mempool_destroy(state->pool);
+}
+
+int bch_bset_sort_state_init(struct bset_sort_state *state, unsigned page_order)
+{
+ spin_lock_init(&state->time.lock);
+
+ state->page_order = page_order;
+ state->crit_factor = int_sqrt(1 << page_order);
+
+ state->pool = mempool_create_page_pool(1, page_order);
+ if (!state->pool)
+ return -ENOMEM;
+
+ return 0;
+}
+EXPORT_SYMBOL(bch_bset_sort_state_init);
+
+static void btree_mergesort(struct btree_keys *b, struct bset *out,
+ struct btree_iter *iter,
+ bool fixup, bool remove_stale)
+{
+ int i;
+ struct bkey *k, *last = NULL;
+ BKEY_PADDED(k) tmp;
+ bool (*bad)(struct btree_keys *, const struct bkey *) = remove_stale
+ ? bch_ptr_bad
+ : bch_ptr_invalid;
+
+ /* Heapify the iterator, using our comparison function */
+ for (i = iter->used / 2 - 1; i >= 0; --i)
+ heap_sift(iter, i, b->ops->sort_cmp);
+
+ while (!btree_iter_end(iter)) {
+ if (b->ops->sort_fixup && fixup)
+ k = b->ops->sort_fixup(iter, &tmp.k);
+ else
+ k = NULL;
+
+ if (!k)
+ k = __bch_btree_iter_next(iter, b->ops->sort_cmp);
+
+ if (bad(b, k))
+ continue;
+
+ if (!last) {
+ last = out->start;
+ bkey_copy(last, k);
+ } else if (!bch_bkey_try_merge(b, last, k)) {
+ last = bkey_next(last);
+ bkey_copy(last, k);
+ }
+ }
+
+ out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
+
+ pr_debug("sorted %i keys", out->keys);
+}
+
+static void __btree_sort(struct btree_keys *b, struct btree_iter *iter,
+ unsigned start, unsigned order, bool fixup,
+ struct bset_sort_state *state)
+{
+ uint64_t start_time;
+ bool used_mempool = false;
+ struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOWAIT,
+ order);
+ if (!out) {
+ struct page *outp;
+
+ BUG_ON(order > state->page_order);
+
+ outp = mempool_alloc(state->pool, GFP_NOIO);
+ out = page_address(outp);
+ used_mempool = true;
+ order = state->page_order;
+ }
+
+ start_time = local_clock();
+
+ btree_mergesort(b, out, iter, fixup, false);
+ b->nsets = start;
+
+ if (!start && order == b->page_order) {
+ /*
+ * Our temporary buffer is the same size as the btree node's
+ * buffer, we can just swap buffers instead of doing a big
+ * memcpy()
+ */
+
+ out->magic = b->set->data->magic;
+ out->seq = b->set->data->seq;
+ out->version = b->set->data->version;
+ swap(out, b->set->data);
+ } else {
+ b->set[start].data->keys = out->keys;
+ memcpy(b->set[start].data->start, out->start,
+ (void *) bset_bkey_last(out) - (void *) out->start);
+ }
+
+ if (used_mempool)
+ mempool_free(virt_to_page(out), state->pool);
+ else
+ free_pages((unsigned long) out, order);
+
+ bch_bset_build_written_tree(b);
+
+ if (!start)
+ bch_time_stats_update(&state->time, start_time);
+}
+
+void bch_btree_sort_partial(struct btree_keys *b, unsigned start,
+ struct bset_sort_state *state)
+{
+ size_t order = b->page_order, keys = 0;
+ struct btree_iter iter;
+ int oldsize = bch_count_data(b);
+
+ __bch_btree_iter_init(b, &iter, NULL, &b->set[start]);
+
+ if (start) {
+ unsigned i;
+
+ for (i = start; i <= b->nsets; i++)
+ keys += b->set[i].data->keys;
+
+ order = get_order(__set_bytes(b->set->data, keys));
+ }
+
+ __btree_sort(b, &iter, start, order, false, state);
+
+ EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize);
+}
+EXPORT_SYMBOL(bch_btree_sort_partial);
+
+void bch_btree_sort_and_fix_extents(struct btree_keys *b,
+ struct btree_iter *iter,
+ struct bset_sort_state *state)
+{
+ __btree_sort(b, iter, 0, b->page_order, true, state);
+}
+
+void bch_btree_sort_into(struct btree_keys *b, struct btree_keys *new,
+ struct bset_sort_state *state)
+{
+ uint64_t start_time = local_clock();
+
+ struct btree_iter iter;
+ bch_btree_iter_init(b, &iter, NULL);
+
+ btree_mergesort(b, new->set->data, &iter, false, true);
+
+ bch_time_stats_update(&state->time, start_time);
+
+ new->set->size = 0; // XXX: why?
+}
+
+#define SORT_CRIT (4096 / sizeof(uint64_t))
+
+void bch_btree_sort_lazy(struct btree_keys *b, struct bset_sort_state *state)
+{
+ unsigned crit = SORT_CRIT;
+ int i;
+
+ /* Don't sort if nothing to do */
+ if (!b->nsets)
+ goto out;
+
+ for (i = b->nsets - 1; i >= 0; --i) {
+ crit *= state->crit_factor;
+
+ if (b->set[i].data->keys < crit) {
+ bch_btree_sort_partial(b, i, state);
+ return;
+ }
+ }
+
+ /* Sort if we'd overflow */
+ if (b->nsets + 1 == MAX_BSETS) {
+ bch_btree_sort(b, state);
+ return;
+ }
+
+out:
+ bch_bset_build_written_tree(b);
+}
+EXPORT_SYMBOL(bch_btree_sort_lazy);
+
+void bch_btree_keys_stats(struct btree_keys *b, struct bset_stats *stats)
+{
+ unsigned i;
+
+ for (i = 0; i <= b->nsets; i++) {
+ struct bset_tree *t = &b->set[i];
+ size_t bytes = t->data->keys * sizeof(uint64_t);
+ size_t j;
+
+ if (bset_written(b, t)) {
+ stats->sets_written++;
+ stats->bytes_written += bytes;
+
+ stats->floats += t->size - 1;
+
+ for (j = 1; j < t->size; j++)
+ if (t->tree[j].exponent == 127)
+ stats->failed++;
+ } else {
+ stats->sets_unwritten++;
+ stats->bytes_unwritten += bytes;
+ }
+ }
+}
Code Review / kvmfornfv.git / blobdiff