bcachefs: Introduce bch2_journal_keys_peek_(upto|slot)()

When many journal replay keys have been overwritten,
bch2_journal_keys_peek() was taking excessively long to scan before it
found a key to return.

Fix this by introducing bch2_journal_keys_peek_upto() which takes a
parameter for the end of the range we want, so that we can terminate the
search much sooner, and replace all uses of bch2_journal_keys_peek()
with peek_upto() or peek_slot().

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

4 files changed, 30 insertions, 21 deletions

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 25d254ee9eac..7f7bf13df696 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -2233,12 +2233,11 @@ struct bkey_s_c btree_trans_peek_journal(struct btree_trans *trans,
 					 struct bkey_s_c k)
 {
 	struct bkey_i *next_journal =
-		bch2_journal_keys_peek(trans->c, iter->btree_id, 0,
-				       iter->path->pos);
+		bch2_journal_keys_peek_upto(trans->c, iter->btree_id, 0,
+				iter->path->pos,
+				k.k ? k.k->p : iter->path->l[0].b->key.k.p);
 
-	if (next_journal &&
-	    bpos_cmp(next_journal->k.p,
-		     k.k ? k.k->p : iter->path->l[0].b->key.k.p) <= 0) {
+	if (next_journal) {
 		iter->k = next_journal->k;
 		k = bkey_i_to_s_c(next_journal);
 	}
@@ -2687,9 +2686,8 @@ struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
 		}
 
 		if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL) &&
-		    (next_update = bch2_journal_keys_peek(trans->c, iter->btree_id,
-							  0, iter->pos)) &&
-		    !bpos_cmp(next_update->k.p, iter->pos)) {
+		    (next_update = bch2_journal_keys_peek_slot(trans->c,
+					iter->btree_id, 0, iter->pos))) {
 			iter->k = next_update->k;
 			k = bkey_i_to_s_c(next_update);
 			goto out;
diff --git a/fs/bcachefs/btree_update_leaf.c b/fs/bcachefs/btree_update_leaf.c
index fccfc0b3a8a2..ef90f7a3d8dc 100644
--- a/fs/bcachefs/btree_update_leaf.c
+++ b/fs/bcachefs/btree_update_leaf.c
@@ -664,9 +664,10 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
 
 		if (unlikely(!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags))) {
 			struct bkey_i *j_k =
-				bch2_journal_keys_peek(c, i->btree_id, i->level, i->k->k.p);
+				bch2_journal_keys_peek_slot(c, i->btree_id, i->level,
+							    i->k->k.p);
 
-			if (j_k && !bpos_cmp(j_k->k.p, i->k->k.p)) {
+			if (j_k) {
 				i->old_k = j_k->k;
 				i->old_v = &j_k->v;
 			}
@@ -1531,9 +1532,9 @@ bch2_trans_update_by_path(struct btree_trans *trans, struct btree_path *path,
 
 		if (unlikely(!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags))) {
 			struct bkey_i *j_k =
-				bch2_journal_keys_peek(c, n.btree_id, n.level, k->k.p);
+				bch2_journal_keys_peek_slot(c, n.btree_id, n.level, k->k.p);
 
-			if (j_k && !bpos_cmp(j_k->k.p, i->k->k.p)) {
+			if (j_k) {
 				i->old_k = j_k->k;
 				i->old_v = &j_k->v;
 			}
diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index 80befab87f2d..80acbc7d3efa 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -109,26 +109,34 @@ size_t bch2_journal_key_search(struct journal_keys *keys,
 	return idx_to_pos(keys, l);
 }
 
-struct bkey_i *bch2_journal_keys_peek(struct bch_fs *c, enum btree_id btree_id,
-				      unsigned level, struct bpos pos)
+struct bkey_i *bch2_journal_keys_peek_upto(struct bch_fs *c, enum btree_id btree_id,
+					   unsigned level, struct bpos pos,
+					   struct bpos end_pos)
 {
 	struct journal_keys *keys = &c->journal_keys;
 	size_t idx = bch2_journal_key_search(keys, btree_id, level, pos);
 
 	while (idx < keys->size &&
-	       keys->d[idx].overwritten) {
+	       keys->d[idx].btree_id == btree_id &&
+	       keys->d[idx].level == level &&
+	       bpos_cmp(keys->d[idx].k->k.p, end_pos) <= 0) {
+		if (!keys->d[idx].overwritten)
+			return keys->d[idx].k;
+
 		idx++;
 		if (idx == keys->gap)
 			idx += keys->size - keys->nr;
 	}
 
-	if (idx < keys->size &&
-	    keys->d[idx].btree_id == btree_id &&
-	    keys->d[idx].level == level)
-		return keys->d[idx].k;
 	return NULL;
 }
 
+struct bkey_i *bch2_journal_keys_peek_slot(struct bch_fs *c, enum btree_id btree_id,
+					   unsigned level, struct bpos pos)
+{
+	return bch2_journal_keys_peek_upto(c, btree_id, level, pos, pos);
+}
+
 static void journal_iters_fix(struct bch_fs *c)
 {
 	struct journal_keys *keys = &c->journal_keys;
diff --git a/fs/bcachefs/recovery.h b/fs/bcachefs/recovery.h
index ab8b116ac7db..e05aac64185d 100644
--- a/fs/bcachefs/recovery.h
+++ b/fs/bcachefs/recovery.h
@@ -30,8 +30,10 @@ struct btree_and_journal_iter {
 
 size_t bch2_journal_key_search(struct journal_keys *, enum btree_id,
 			       unsigned, struct bpos);
-struct bkey_i *bch2_journal_keys_peek(struct bch_fs *, enum btree_id,
-				      unsigned, struct bpos pos);
+struct bkey_i *bch2_journal_keys_peek_upto(struct bch_fs *, enum btree_id,
+					   unsigned, struct bpos, struct bpos);
+struct bkey_i *bch2_journal_keys_peek_slot(struct bch_fs *, enum btree_id,
+					   unsigned, struct bpos);
 
 int bch2_journal_key_insert_take(struct bch_fs *, enum btree_id,
 				 unsigned, struct bkey_i *);