bcache: Add btree_map() functions
Lots of stuff has been open coding its own btree traversal - which is
generally pretty simple code, but there are a few subtleties.
This adds new new functions, bch_btree_map_nodes() and
bch_btree_map_keys(), which do the traversal for you. Everything that's
open coding btree traversal now (with the exception of garbage
collection) is slowly going to be converted to these two functions;
being able to write other code at a higher level of abstraction is a
big improvement w.r.t. overall code quality.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 17bfd87..cfbdcf3 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -2296,6 +2296,82 @@
return ret;
}
+/* Map across nodes or keys */
+
+static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
+ struct bkey *from,
+ btree_map_nodes_fn *fn, int flags)
+{
+ int ret = MAP_CONTINUE;
+
+ if (b->level) {
+ struct bkey *k;
+ struct btree_iter iter;
+
+ bch_btree_iter_init(b, &iter, from);
+
+ while ((k = bch_btree_iter_next_filter(&iter, b,
+ bch_ptr_bad))) {
+ ret = btree(map_nodes_recurse, k, b,
+ op, from, fn, flags);
+ from = NULL;
+
+ if (ret != MAP_CONTINUE)
+ return ret;
+ }
+ }
+
+ if (!b->level || flags == MAP_ALL_NODES)
+ ret = fn(op, b);
+
+ return ret;
+}
+
+int __bch_btree_map_nodes(struct btree_op *op, struct cache_set *c,
+ struct bkey *from, btree_map_nodes_fn *fn, int flags)
+{
+ int ret = btree_root(map_nodes_recurse, c, op, from, fn, flags);
+ if (closure_blocking(&op->cl))
+ closure_sync(&op->cl);
+ return ret;
+}
+
+static int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
+ struct bkey *from, btree_map_keys_fn *fn,
+ int flags)
+{
+ int ret = MAP_CONTINUE;
+ struct bkey *k;
+ struct btree_iter iter;
+
+ bch_btree_iter_init(b, &iter, from);
+
+ while ((k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad))) {
+ ret = !b->level
+ ? fn(op, b, k)
+ : btree(map_keys_recurse, k, b, op, from, fn, flags);
+ from = NULL;
+
+ if (ret != MAP_CONTINUE)
+ return ret;
+ }
+
+ if (!b->level && (flags & MAP_END_KEY))
+ ret = fn(op, b, &KEY(KEY_INODE(&b->key),
+ KEY_OFFSET(&b->key), 0));
+
+ return ret;
+}
+
+int bch_btree_map_keys(struct btree_op *op, struct cache_set *c,
+ struct bkey *from, btree_map_keys_fn *fn, int flags)
+{
+ int ret = btree_root(map_keys_recurse, c, op, from, fn, flags);
+ if (closure_blocking(&op->cl))
+ closure_sync(&op->cl);
+ return ret;
+}
+
/* Keybuf code */
static inline int keybuf_cmp(struct keybuf_key *l, struct keybuf_key *r)
@@ -2314,74 +2390,70 @@
return clamp_t(int64_t, bkey_cmp(&l->key, &r->key), -1, 1);
}
-static int bch_btree_refill_keybuf(struct btree *b, struct btree_op *op,
- struct keybuf *buf, struct bkey *end,
- keybuf_pred_fn *pred)
+struct refill {
+ struct btree_op op;
+ struct keybuf *buf;
+ struct bkey *end;
+ keybuf_pred_fn *pred;
+};
+
+static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
+ struct bkey *k)
{
- struct btree_iter iter;
- bch_btree_iter_init(b, &iter, &buf->last_scanned);
+ struct refill *refill = container_of(op, struct refill, op);
+ struct keybuf *buf = refill->buf;
+ int ret = MAP_CONTINUE;
- while (!array_freelist_empty(&buf->freelist)) {
- struct bkey *k = bch_btree_iter_next_filter(&iter, b,
- bch_ptr_bad);
-
- if (!b->level) {
- if (!k) {
- buf->last_scanned = b->key;
- break;
- }
-
- buf->last_scanned = *k;
- if (bkey_cmp(&buf->last_scanned, end) >= 0)
- break;
-
- if (pred(buf, k)) {
- struct keybuf_key *w;
-
- spin_lock(&buf->lock);
-
- w = array_alloc(&buf->freelist);
-
- w->private = NULL;
- bkey_copy(&w->key, k);
-
- if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
- array_free(&buf->freelist, w);
-
- spin_unlock(&buf->lock);
- }
- } else {
- if (!k)
- break;
-
- btree(refill_keybuf, k, b, op, buf, end, pred);
- /*
- * Might get an error here, but can't really do anything
- * and it'll get logged elsewhere. Just read what we
- * can.
- */
-
- if (bkey_cmp(&buf->last_scanned, end) >= 0)
- break;
-
- cond_resched();
- }
+ if (bkey_cmp(k, refill->end) >= 0) {
+ ret = MAP_DONE;
+ goto out;
}
- return 0;
+ if (!KEY_SIZE(k)) /* end key */
+ goto out;
+
+ if (refill->pred(buf, k)) {
+ struct keybuf_key *w;
+
+ spin_lock(&buf->lock);
+
+ w = array_alloc(&buf->freelist);
+ if (!w) {
+ spin_unlock(&buf->lock);
+ return MAP_DONE;
+ }
+
+ w->private = NULL;
+ bkey_copy(&w->key, k);
+
+ if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
+ array_free(&buf->freelist, w);
+
+ if (array_freelist_empty(&buf->freelist))
+ ret = MAP_DONE;
+
+ spin_unlock(&buf->lock);
+ }
+out:
+ buf->last_scanned = *k;
+ return ret;
}
void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
struct bkey *end, keybuf_pred_fn *pred)
{
struct bkey start = buf->last_scanned;
- struct btree_op op;
- bch_btree_op_init_stack(&op);
+ struct refill refill;
cond_resched();
- btree_root(refill_keybuf, c, &op, buf, end, pred);
- closure_sync(&op.cl);
+ bch_btree_op_init_stack(&refill.op);
+ refill.buf = buf;
+ refill.end = end;
+ refill.pred = pred;
+
+ bch_btree_map_keys(&refill.op, c, &buf->last_scanned,
+ refill_keybuf_fn, MAP_END_KEY);
pr_debug("found %s keys from %llu:%llu to %llu:%llu",
RB_EMPTY_ROOT(&buf->keys) ? "no" :
@@ -2465,9 +2537,9 @@
}
struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *c,
- struct keybuf *buf,
- struct bkey *end,
- keybuf_pred_fn *pred)
+ struct keybuf *buf,
+ struct bkey *end,
+ keybuf_pred_fn *pred)
{
struct keybuf_key *ret;