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>
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 1a7530c..6def7c9 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -2025,15 +2025,16 @@
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 @@
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 @@
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 @@
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,