diff options
Diffstat (limited to 'drivers/md/bcache/bset.c')
| -rw-r--r-- | drivers/md/bcache/bset.c | 1190 |
1 files changed, 1190 insertions, 0 deletions
diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c new file mode 100644 index 000000000000..bb0f7ae14b3c --- /dev/null +++ b/drivers/md/bcache/bset.c @@ -0,0 +1,1190 @@ +/* + * Code for working with individual keys, and sorted sets of keys with in a + * btree node + * + * Copyright 2012 Google, Inc. + */ + +#include "bcache.h" +#include "btree.h" +#include "debug.h" + +#include <linux/random.h> + +/* Keylists */ + +void bch_keylist_copy(struct keylist *dest, struct keylist *src) +{ + *dest = *src; + + if (src->list == src->d) { + size_t n = (uint64_t *) src->top - src->d; + dest->top = (struct bkey *) &dest->d[n]; + dest->list = dest->d; + } +} + +int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c) +{ + unsigned oldsize = (uint64_t *) l->top - l->list; + unsigned newsize = oldsize + 2 + nptrs; + uint64_t *new; + + /* The journalling code doesn't handle the case where the keys to insert + * is bigger than an empty write: If we just return -ENOMEM here, + * bio_insert() and bio_invalidate() will insert the keys created so far + * and finish the rest when the keylist is empty. + */ + if (newsize * sizeof(uint64_t) > block_bytes(c) - sizeof(struct jset)) + return -ENOMEM; + + newsize = roundup_pow_of_two(newsize); + + if (newsize <= KEYLIST_INLINE || + roundup_pow_of_two(oldsize) == newsize) + return 0; + + new = krealloc(l->list == l->d ? NULL : l->list, + sizeof(uint64_t) * newsize, GFP_NOIO); + + if (!new) + return -ENOMEM; + + if (l->list == l->d) + memcpy(new, l->list, sizeof(uint64_t) * KEYLIST_INLINE); + + l->list = new; + l->top = (struct bkey *) (&l->list[oldsize]); + + return 0; +} + +struct bkey *bch_keylist_pop(struct keylist *l) +{ + struct bkey *k = l->bottom; + + if (k == l->top) + return NULL; + + while (bkey_next(k) != l->top) + k = bkey_next(k); + + return l->top = k; +} + +/* Pointer validation */ + +bool __bch_ptr_invalid(struct cache_set *c, int level, const struct bkey *k) +{ + unsigned i; + + if (level && (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k))) + goto bad; + + if (!level && KEY_SIZE(k) > KEY_OFFSET(k)) + goto bad; + + if (!KEY_SIZE(k)) + return true; + + for (i = 0; i < KEY_PTRS(k); i++) + if (ptr_available(c, k, i)) { + struct cache *ca = PTR_CACHE(c, k, i); + size_t bucket = PTR_BUCKET_NR(c, k, i); + size_t r = bucket_remainder(c, PTR_OFFSET(k, i)); + + if (KEY_SIZE(k) + r > c->sb.bucket_size || + bucket < ca->sb.first_bucket || + bucket >= ca->sb.nbuckets) + goto bad; + } + + return false; +bad: + cache_bug(c, "spotted bad key %s: %s", pkey(k), bch_ptr_status(c, k)); + return true; +} + +bool bch_ptr_bad(struct btree *b, const struct bkey *k) +{ + struct bucket *g; + unsigned i, stale; + + if (!bkey_cmp(k, &ZERO_KEY) || + !KEY_PTRS(k) || + bch_ptr_invalid(b, k)) + return true; + + if (KEY_PTRS(k) && PTR_DEV(k, 0) == PTR_CHECK_DEV) + return true; + + for (i = 0; i < KEY_PTRS(k); i++) + if (ptr_available(b->c, k, i)) { + g = PTR_BUCKET(b->c, k, i); + stale = ptr_stale(b->c, k, i); + + btree_bug_on(stale > 96, b, + "key too stale: %i, need_gc %u", + stale, b->c->need_gc); + + btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k), + b, "stale dirty pointer"); + + if (stale) + return true; + +#ifdef CONFIG_BCACHE_EDEBUG + if (!mutex_trylock(&b->c->bucket_lock)) + continue; + + if (b->level) { + if (KEY_DIRTY(k) || + g->prio != BTREE_PRIO || + (b->c->gc_mark_valid && + GC_MARK(g) != GC_MARK_METADATA)) + goto bug; + + } else { + if (g->prio == BTREE_PRIO) + goto bug; + + if (KEY_DIRTY(k) && + b->c->gc_mark_valid && + GC_MARK(g) != GC_MARK_DIRTY) + goto bug; + } + mutex_unlock(&b->c->bucket_lock); +#endif + } + + return false; +#ifdef CONFIG_BCACHE_EDEBUG +bug: + mutex_unlock(&b->c->bucket_lock); + btree_bug(b, "inconsistent pointer %s: bucket %li pin %i " + "prio %i gen %i last_gc %i mark %llu gc_gen %i", pkey(k), + PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin), + g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen); + return true; +#endif +} + +/* 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; +} + +static uint64_t merge_chksums(struct bkey *l, struct bkey *r) +{ + return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) & + ~((uint64_t)1 << 63); +} + +/* 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 *b, struct bkey *l, struct bkey *r) +{ + unsigned i; + + if (key_merging_disabled(b->c)) + return false; + + if (KEY_PTRS(l) != KEY_PTRS(r) || + KEY_DIRTY(l) != KEY_DIRTY(r) || + bkey_cmp(l, &START_KEY(r))) + return false; + + for (i = 0; i < KEY_PTRS(l); i++) + if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] || + PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i)) + return false; + + /* Keys with no pointers aren't restricted to one bucket and could + * overflow KEY_SIZE + */ + if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) { + SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l)); + SET_KEY_SIZE(l, USHRT_MAX); + + bch_cut_front(l, r); + return false; + } + + if (KEY_CSUM(l)) { + if (KEY_CSUM(r)) + l->ptr[KEY_PTRS(l)] = merge_chksums(l, r); + else + SET_KEY_CSUM(l, 0); + } + + SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r)); + SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r)); + + return true; +} + +/* 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 arithmatic: + * + * 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 arithmatic 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 bkey *k) +{ + return ((size_t) k & (BSET_CACHELINE - 1)) / sizeof(uint64_t); +} + +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) +{ +#ifdef CONFIG_X86_64 + asm("shrd %[shift],%[high],%[low]" + : [low] "+Rm" (low) + : [high] "R" (high), + [shift] "ci" (shift) + : "cc"); +#else + low >>= shift; + low |= (high << 1) << (63U - shift); +#endif + 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) + ? node(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 *b, struct bset_tree *t) +{ + if (t != b->sets) { + 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->sets + MAX_BSETS) + t++->size = 0; +} + +static void bset_build_unwritten_tree(struct btree *b) +{ + struct bset_tree *t = b->sets + b->nsets; + + bset_alloc_tree(b, t); + + if (t->tree != b->sets->tree + bset_tree_space(b)) { + t->prev[0] = bkey_to_cacheline_offset(t->data->start); + t->size = 1; + } +} + +static void bset_build_written_tree(struct btree *b) +{ + struct bset_tree *t = b->sets + b->nsets; + struct bkey *k = t->data->start; + unsigned j, cacheline = 1; + + bset_alloc_tree(b, t); + + t->size = min_t(unsigned, + bkey_to_cacheline(t, end(t->data)), + b->sets->tree + bset_tree_space(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) + k = bkey_next(k); + + t->prev[j] = bkey_u64s(k); + k = bkey_next(k); + cacheline++; + t->tree[j].m = bkey_to_cacheline_offset(k); + } + + while (bkey_next(k) != end(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); +} + +void bch_bset_fix_invalidated_key(struct btree *b, struct bkey *k) +{ + struct bset_tree *t; + unsigned inorder, j = 1; + + for (t = b->sets; t <= &b->sets[b->nsets]; t++) + if (k < end(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) == end(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); +} + +void bch_bset_fix_lookup_table(struct btree *b, struct bkey *k) +{ + struct bset_tree *t = &b->sets[b->nsets]; + 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 + */ + if (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(k); + } + } + + if (t->size == b->sets->tree + bset_tree_space(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 != end(t->data); + k = bkey_next(k)) + if (t->size == bkey_to_cacheline(t, k)) { + t->prev[t->size] = bkey_to_cacheline_offset(k); + t->size++; + } +} + +void bch_bset_init_next(struct btree *b) +{ + struct bset *i = write_block(b); + + if (i != b->sets[0].data) { + b->sets[++b->nsets].data = i; + i->seq = b->sets[0].data->seq; + } else + get_random_bytes(&i->seq, sizeof(uint64_t)); + + i->magic = bset_magic(b->c); + i->version = 0; + i->keys = 0; + + bset_build_unwritten_tree(b); +} + +struct bset_search_iter { + struct bkey *l, *r; +}; + +static struct bset_search_iter bset_search_write_set(struct btree *b, + struct bset_tree *t, + const struct bkey *search) +{ + unsigned li = 0, ri = t->size; + + BUG_ON(!b->nsets && + t->size < bkey_to_cacheline(t, end(t->data))); + + 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) : end(t->data) + }; +} + +static struct bset_search_iter bset_search_tree(struct btree *b, + 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 = end(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 *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 = end(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 end(t->data); + + if (unlikely(bkey_cmp(search, t->data->start) < 0)) + return t->data->start; + + i = bset_search_tree(b, t, search); + } else + i = bset_search_write_set(b, t, search); + +#ifdef CONFIG_BCACHE_EDEBUG + 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 != end(t->data) && + bkey_cmp(i.r, search) <= 0); +#endif + + while (likely(i.l != i.r) && + bkey_cmp(i.l, search) <= 0) + i.l = bkey_next(i.l); + + return i.l; +} + +/* Btree iterator */ + +static inline bool btree_iter_cmp(struct btree_iter_set l, + struct btree_iter_set r) +{ + int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k)); + + return c ? c > 0 : l.k < r.k; +} + +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)); +} + +struct bkey *__bch_btree_iter_init(struct btree *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; + + for (; start <= &b->sets[b->nsets]; start++) { + ret = bch_bset_search(b, start, search); + bch_btree_iter_push(iter, ret, end(start->data)); + } + + return ret; +} + +struct bkey *bch_btree_iter_next(struct btree_iter *iter) +{ + struct btree_iter_set unused; + struct bkey *ret = NULL; + + if (!btree_iter_end(iter)) { + ret = iter->data->k; + iter->data->k = bkey_next(iter->data->k); + + if (iter->data->k > iter->data->end) { + __WARN(); + iter->data->k = iter->data->end; + } + + if (iter->data->k == iter->data->end) + heap_pop(iter, unused, btree_iter_cmp); + else + heap_sift(iter, 0, btree_iter_cmp); + } + + return ret; +} + +struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter, + struct btree *b, ptr_filter_fn fn) +{ + struct bkey *ret; + + do { + ret = bch_btree_iter_next(iter); + } while (ret && fn(b, ret)); + + return ret; +} + +struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search) +{ + struct btree_iter iter; + + bch_btree_iter_init(b, &iter, search); + return bch_btree_iter_next_filter(&iter, b, bch_ptr_bad); +} + +/* Mergesort */ + +static void btree_sort_fixup(struct btree_iter *iter) +{ + while (iter->used > 1) { + struct btree_iter_set *top = iter->data, *i = top + 1; + struct bkey *k; + + if (iter->used > 2 && + btree_iter_cmp(i[0], i[1])) + i++; + + for (k = i->k; + k != i->end && bkey_cmp(top->k, &START_KEY(k)) > 0; + k = bkey_next(k)) + if (top->k > i->k) + __bch_cut_front(top->k, k); + else if (KEY_SIZE(k)) + bch_cut_back(&START_KEY(k), top->k); + + if (top->k < i->k || k == i->k) + break; + + heap_sift(iter, i - top, btree_iter_cmp); + } +} + +static void btree_mergesort(struct btree *b, struct bset *out, + struct btree_iter *iter, + bool fixup, bool remove_stale) +{ + struct bkey *k, *last = NULL; + bool (*bad)(struct btree *, const struct bkey *) = remove_stale + ? bch_ptr_bad + : bch_ptr_invalid; + + while (!btree_iter_end(iter)) { + if (fixup && !b->level) + btree_sort_fixup(iter); + + k = bch_btree_iter_next(iter); + if (bad(b, k)) + continue; + + if (!last) { + last = out->start; + bkey_copy(last, k); + } else if (b->level || + !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); + bch_check_key_order(b, out); +} + +static void __btree_sort(struct btree *b, struct btree_iter *iter, + unsigned start, unsigned order, bool fixup) +{ + uint64_t start_time; + bool remove_stale = !b->written; + struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOIO, + order); + if (!out) { + mutex_lock(&b->c->sort_lock); + out = b->c->sort; + order = ilog2(bucket_pages(b->c)); + } + + start_time = local_clock(); + + btree_mergesort(b, out, iter, fixup, remove_stale); + b->nsets = start; + + if (!fixup && !start && b->written) + bch_btree_verify(b, out); + + 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 = bset_magic(b->c); + out->seq = b->sets[0].data->seq; + out->version = b->sets[0].data->version; + swap(out, b->sets[0].data); + + if (b->c->sort == b->sets[0].data) + b->c->sort = out; + } else { + b->sets[start].data->keys = out->keys; + memcpy(b->sets[start].data->start, out->start, + (void *) end(out) - (void *) out->start); + } + + if (out == b->c->sort) + mutex_unlock(&b->c->sort_lock); + else + free_pages((unsigned long) out, order); + + if (b->written) + bset_build_written_tree(b); + + if (!start) { + spin_lock(&b->c->sort_time_lock); + time_stats_update(&b->c->sort_time, start_time); + spin_unlock(&b->c->sort_time_lock); + } +} + +void bch_btree_sort_partial(struct btree *b, unsigned start) +{ + size_t oldsize = 0, order = b->page_order, keys = 0; + struct btree_iter iter; + __bch_btree_iter_init(b, &iter, NULL, &b->sets[start]); + + BUG_ON(b->sets[b->nsets].data == write_block(b) && + (b->sets[b->nsets].size || b->nsets)); + + if (b->written) + oldsize = bch_count_data(b); + + if (start) { + unsigned i; + + for (i = start; i <= b->nsets; i++) + keys += b->sets[i].data->keys; + + order = roundup_pow_of_two(__set_bytes(b->sets->data, keys)) / PAGE_SIZE; + if (order) + order = ilog2(order); + } + + __btree_sort(b, &iter, start, order, false); + + EBUG_ON(b->written && bch_count_data(b) != oldsize); +} + +void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter) +{ + BUG_ON(!b->written); + __btree_sort(b, iter, 0, b->page_order, true); +} + +void bch_btree_sort_into(struct btree *b, struct btree *new) +{ + uint64_t start_time = local_clock(); + + struct btree_iter iter; + bch_btree_iter_init(b, &iter, NULL); + + btree_mergesort(b, new->sets->data, &iter, false, true); + + spin_lock(&b->c->sort_time_lock); + time_stats_update(&b->c->sort_time, start_time); + spin_unlock(&b->c->sort_time_lock); + + bkey_copy_key(&new->key, &b->key); + new->sets->size = 0; +} + +void bch_btree_sort_lazy(struct btree *b) +{ + if (b->nsets) { + unsigned i, j, keys = 0, total; + + for (i = 0; i <= b->nsets; i++) + keys += b->sets[i].data->keys; + + total = keys; + + for (j = 0; j < b->nsets; j++) { + if (keys * 2 < total || + keys < 1000) { + bch_btree_sort_partial(b, j); + return; + } + + keys -= b->sets[j].data->keys; + } + + /* Must sort if b->nsets == 3 or we'll overflow */ + if (b->nsets >= (MAX_BSETS - 1) - b->level) { + bch_btree_sort(b); + return; + } + } + + bset_build_written_tree(b); +} + +/* Sysfs stuff */ + +struct bset_stats { + size_t nodes; + size_t sets_written, sets_unwritten; + size_t bytes_written, bytes_unwritten; + size_t floats, failed; +}; + +static int bch_btree_bset_stats(struct btree *b, struct btree_op *op, + struct bset_stats *stats) +{ + struct bkey *k; + unsigned i; + + stats->nodes++; + + for (i = 0; i <= b->nsets; i++) { + struct bset_tree *t = &b->sets[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; + } + } + + if (b->level) { + struct btree_iter iter; + + for_each_key_filter(b, k, &iter, bch_ptr_bad) { + int ret = btree(bset_stats, k, b, op, stats); + if (ret) + return ret; + } + } + + return 0; +} + +int bch_bset_print_stats(struct cache_set *c, char *buf) +{ + struct btree_op op; + struct bset_stats t; + int ret; + + bch_btree_op_init_stack(&op); + memset(&t, 0, sizeof(struct bset_stats)); + + ret = btree_root(bset_stats, c, &op, &t); + if (ret) + return ret; + + return snprintf(buf, PAGE_SIZE, + "btree nodes: %zu\n" + "written sets: %zu\n" + "unwritten sets: %zu\n" + "written key bytes: %zu\n" + "unwritten key bytes: %zu\n" + "floats: %zu\n" + "failed: %zu\n", + t.nodes, + t.sets_written, t.sets_unwritten, + t.bytes_written, t.bytes_unwritten, + t.floats, t.failed); +} |