blob: 22d1ae72c2826a53b67656a59ea717a62a3b95a4 [file] [log] [blame]
/*
* 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>
#include <linux/prefetch.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;
char buf[80];
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:
bch_bkey_to_text(buf, sizeof(buf), k);
cache_bug(c, "spotted bad key %s: %s", buf, 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);
{
char buf[80];
bch_bkey_to_text(buf, sizeof(buf), k);
btree_bug(b,
"inconsistent pointer %s: bucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
buf, 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 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 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_ONCE(1, "bset was corrupt!\n");
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 sort_key_next(struct btree_iter *iter,
struct btree_iter_set *i)
{
i->k = bkey_next(i->k);
if (i->k == i->end)
*i = iter->data[--iter->used];
}
static void btree_sort_fixup(struct btree_iter *iter)
{
while (iter->used > 1) {
struct btree_iter_set *top = iter->data, *i = top + 1;
if (iter->used > 2 &&
btree_iter_cmp(i[0], i[1]))
i++;
if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
break;
if (!KEY_SIZE(i->k)) {
sort_key_next(iter, i);
heap_sift(iter, i - top, btree_iter_cmp);
continue;
}
if (top->k > i->k) {
if (bkey_cmp(top->k, i->k) >= 0)
sort_key_next(iter, i);
else
bch_cut_front(top->k, i->k);
heap_sift(iter, i - top, btree_iter_cmp);
} else {
/* can't happen because of comparison func */
BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
bch_cut_back(&START_KEY(i->k), top->k);
}
}
}
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);
bch_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);
bch_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;
}
#define SORT_CRIT (4096 / sizeof(uint64_t))
void bch_btree_sort_lazy(struct btree *b)
{
unsigned crit = SORT_CRIT;
int i;
/* Don't sort if nothing to do */
if (!b->nsets)
goto out;
/* If not a leaf node, always sort */
if (b->level) {
bch_btree_sort(b);
return;
}
for (i = b->nsets - 1; i >= 0; --i) {
crit *= b->c->sort_crit_factor;
if (b->sets[i].data->keys < crit) {
bch_btree_sort_partial(b, i);
return;
}
}
/* Sort if we'd overflow */
if (b->nsets + 1 == MAX_BSETS) {
bch_btree_sort(b);
return;
}
out:
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);
}