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>

1 files changed, 15 insertions, 7 deletions

diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index 9269cb686e4d..16ba5d24a86d 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;