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bcache: Have btree_split() insert into parent directly 

The flow control in btree_insert_node() was... fragile... before,
this'll use more stack (but since our btrees are never more than depth
1, that shouldn't matter) and it should be significantly clearer and
less fragile.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
hifive-unleashed-5.1
Kent Overstreet 2013-07-26 12:32:38 -07:00
parent 65d22e911b
commit 17e21a9f24
1 changed files with 39 additions and 46 deletions
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85
drivers/md/bcache/btree.c
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@ -2025,15 +2025,16 @@ static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op,
static int btree_split(struct btree *b, struct btree_op *op,
struct keylist *insert_keys,
struct keylist *parent_keys,
struct bkey *replace_key)
{
bool split;
struct btree *n1, *n2 = NULL, *n3 = NULL;
uint64_t start_time = local_clock();
struct closure cl;
struct keylist parent_keys;
closure_init_stack(&cl);
bch_keylist_init(&parent_keys);
n1 = btree_node_alloc_replacement(b, true);
if (IS_ERR(n1))
@ -2078,7 +2079,7 @@ static int btree_split(struct btree *b, struct btree_op *op,
bkey_copy_key(&n2->key, &b->key);
bch_keylist_add(parent_keys, &n2->key);
bch_keylist_add(&parent_keys, &n2->key);
bch_btree_node_write(n2, &cl);
rw_unlock(true, n2);
} else {
@ -2087,33 +2088,39 @@ static int btree_split(struct btree *b, struct btree_op *op,
bch_btree_insert_keys(n1, op, insert_keys, replace_key);
}
bch_keylist_add(parent_keys, &n1->key);
bch_keylist_add(&parent_keys, &n1->key);
bch_btree_node_write(n1, &cl);
if (n3) {
/* Depth increases, make a new root */
bkey_copy_key(&n3->key, &MAX_KEY);
bch_btree_insert_keys(n3, op, parent_keys, NULL);
bch_btree_insert_keys(n3, op, &parent_keys, NULL);
bch_btree_node_write(n3, &cl);
closure_sync(&cl);
bch_btree_set_root(n3);
rw_unlock(true, n3);
btree_node_free(b);
} else if (!b->parent) {
/* Root filled up but didn't need to be split */
bch_keylist_reset(parent_keys);
closure_sync(&cl);
bch_btree_set_root(n1);
btree_node_free(b);
} else {
/* Split a non root node */
closure_sync(&cl);
make_btree_freeing_key(b, parent_keys->top);
bch_keylist_push(parent_keys);
make_btree_freeing_key(b, parent_keys.top);
bch_keylist_push(&parent_keys);
btree_node_free(b);
bch_btree_insert_node(b->parent, op, &parent_keys, NULL, NULL);
BUG_ON(!bch_keylist_empty(&parent_keys));
}
rw_unlock(true, n1);
btree_node_free(b);
bch_time_stats_update(&b->c->btree_split_time, start_time);
@ -2139,46 +2146,32 @@ static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
atomic_t *journal_ref,
struct bkey *replace_key)
{
int ret = 0;
struct keylist split_keys;
BUG_ON(b->level && replace_key);
bch_keylist_init(&split_keys);
do {
BUG_ON(b->level && replace_key);
if (should_split(b)) {
if (current->bio_list) {
op->lock = b->c->root->level + 1;
ret = -EAGAIN;
} else if (op->lock <= b->c->root->level) {
op->lock = b->c->root->level + 1;
ret = -EINTR;
} else {
struct btree *parent = b->parent;
ret = btree_split(b, op, insert_keys,
&split_keys, replace_key);
insert_keys = &split_keys;
replace_key = NULL;
b = parent;
if (!ret)
ret = -EINTR;
}
if (should_split(b)) {
if (current->bio_list) {
op->lock = b->c->root->level + 1;
return -EAGAIN;
} else if (op->lock <= b->c->root->level) {
op->lock = b->c->root->level + 1;
return -EINTR;
} else {
BUG_ON(write_block(b) != b->sets[b->nsets].data);
if (bch_btree_insert_keys(b, op, insert_keys,
replace_key)) {
if (!b->level)
bch_btree_leaf_dirty(b, journal_ref);
else
bch_btree_node_write_sync(b);
}
/* Invalidated all iterators */
return btree_split(b, op, insert_keys, replace_key) ?:
-EINTR;
}
} while (!bch_keylist_empty(&split_keys));
} else {
BUG_ON(write_block(b) != b->sets[b->nsets].data);
return ret;
if (bch_btree_insert_keys(b, op, insert_keys, replace_key)) {
if (!b->level)
bch_btree_leaf_dirty(b, journal_ref);
else
bch_btree_node_write_sync(b);
}
return 0;
}
}
int bch_btree_insert_check_key(struct btree *b, struct btree_op *op,