bcachefs: Minor btree iter refactoring

This makes the flow control in bch2_btree_iter_peek() and
bch2_btree_iter_peek_prev() a bit cleaner.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index fa19ef141252261fc885d5c4151fc9946f045578..f38f231fb2963e34ffd9b00359b7c989f6c7926c 100644 (file)
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -1696,37 +1696,6 @@ inline bool bch2_btree_iter_rewind(struct btree_iter *iter)
        return ret;
 }
 
-static inline bool btree_iter_set_pos_to_next_leaf(struct btree_iter *iter)
-{
-       struct bpos next_pos = iter->l[0].b->key.k.p;
-       bool ret = bpos_cmp(next_pos, SPOS_MAX) != 0;
-
-       /*
-        * Typically, we don't want to modify iter->pos here, since that
-        * indicates where we searched from - unless we got to the end of the
-        * btree, in that case we want iter->pos to reflect that:
-        */
-       if (ret)
-               btree_iter_set_search_pos(iter, bpos_successor(next_pos));
-       else
-               bch2_btree_iter_set_pos(iter, SPOS_MAX);
-
-       return ret;
-}
-
-static inline bool btree_iter_set_pos_to_prev_leaf(struct btree_iter *iter)
-{
-       struct bpos next_pos = iter->l[0].b->data->min_key;
-       bool ret = bpos_cmp(next_pos, POS_MIN) != 0;
-
-       if (ret)
-               btree_iter_set_search_pos(iter, bpos_predecessor(next_pos));
-       else
-               bch2_btree_iter_set_pos(iter, POS_MIN);
-
-       return ret;
-}
-
 static noinline struct bkey_i *__btree_trans_peek_updates(struct btree_iter *iter)
 {
        struct btree_insert_entry *i;
@@ -1767,10 +1736,10 @@ struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)
        EBUG_ON(btree_iter_type(iter) != BTREE_ITER_KEYS);
        bch2_btree_iter_verify(iter);
        bch2_btree_iter_verify_entry_exit(iter);
-start:
-       btree_iter_set_search_pos(iter, search_key);
 
        while (1) {
+               btree_iter_set_search_pos(iter, search_key);
+
                ret = btree_iter_traverse(iter);
                if (unlikely(ret))
                        return bkey_s_c_err(ret);
@@ -1791,14 +1760,20 @@ start:
                if (likely(k.k)) {
                        if (bkey_deleted(k.k)) {
                                search_key = bkey_successor(iter, k.k->p);
-                               goto start;
+                               continue;
                        }
 
                        break;
                }
 
-               if (!btree_iter_set_pos_to_next_leaf(iter))
-                       return bkey_s_c_null;
+               if (unlikely(!bpos_cmp(iter->l[0].b->key.k.p, SPOS_MAX))) {
+                       bch2_btree_iter_set_pos(iter, SPOS_MAX);
+                       k = bkey_s_c_null;
+                       goto out;
+               }
+
+               /* Advance to next leaf node: */
+               search_key = bpos_successor(iter->l[0].b->key.k.p);
        }
 
        /*
@@ -1810,6 +1785,7 @@ start:
        else if (bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)
                iter->pos = bkey_start_pos(k.k);
 
+out:
        bch2_btree_iter_verify_entry_exit(iter);
        bch2_btree_iter_verify(iter);
        iter->should_be_locked = true;
@@ -1834,6 +1810,7 @@ struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)
  */
 struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
 {
+       struct bpos search_key = iter->pos;
        struct btree_iter_level *l = &iter->l[0];
        struct bkey_s_c k;
        int ret;
@@ -1843,9 +1820,9 @@ struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
        bch2_btree_iter_verify(iter);
        bch2_btree_iter_verify_entry_exit(iter);
 
-       btree_iter_set_search_pos(iter, iter->pos);
-
        while (1) {
+               btree_iter_set_search_pos(iter, search_key);
+
                ret = btree_iter_traverse(iter);
                if (unlikely(ret)) {
                        k = bkey_s_c_err(ret);
@@ -1862,10 +1839,14 @@ struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
                if (likely(k.k))
                        break;
 
-               if (!btree_iter_set_pos_to_prev_leaf(iter)) {
+               if (unlikely(!bpos_cmp(iter->l[0].b->data->min_key, POS_MIN))) {
+                       bch2_btree_iter_set_pos(iter, POS_MIN);
                        k = bkey_s_c_null;
                        goto no_key;
                }
+
+               /* Advance to previous leaf node: */
+               search_key = bpos_predecessor(iter->l[0].b->data->min_key);
        }
 
        EBUG_ON(bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0);