bcachefs: Kill BTREE_UPDATE_PREJOURNAL

With the previous patch that reworks BTREE_INSERT_JOURNAL_REPLAY, we can
now switch the btree write buffer to use it for flushing.

This has the advantage that transaction commits don't need to take a
journal reservation at all.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bkey_methods.h

@@ -93,7 +93,6 @@ static inline int bch2_mark_key(struct btree_trans *trans,
 enum btree_update_flags {
 	__BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE = __BTREE_ITER_FLAGS_END,
 	__BTREE_UPDATE_NOJOURNAL,
-	__BTREE_UPDATE_PREJOURNAL,
 	__BTREE_UPDATE_KEY_CACHE_RECLAIM,
 
 	__BTREE_TRIGGER_NORUN,		/* Don't run triggers at all */
@@ -108,7 +107,6 @@ enum btree_update_flags {
 
 #define BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE (1U << __BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE)
 #define BTREE_UPDATE_NOJOURNAL		(1U << __BTREE_UPDATE_NOJOURNAL)
-#define BTREE_UPDATE_PREJOURNAL		(1U << __BTREE_UPDATE_PREJOURNAL)
 #define BTREE_UPDATE_KEY_CACHE_RECLAIM	(1U << __BTREE_UPDATE_KEY_CACHE_RECLAIM)
 
 #define BTREE_TRIGGER_NORUN		(1U << __BTREE_TRIGGER_NORUN)

fs/bcachefs/btree_trans_commit.c

@@ -778,12 +778,7 @@ bch2_trans_commit_write_locked(struct btree_trans *trans, unsigned flags,
 
 	trans_for_each_update(trans, i) {
 		if (!i->cached) {
-			u64 seq = trans->journal_res.seq;
-
-			if (i->flags & BTREE_UPDATE_PREJOURNAL)
-				seq = i->seq;
-
-			bch2_btree_insert_key_leaf(trans, i->path, i->k, seq);
+			bch2_btree_insert_key_leaf(trans, i->path, i->k, trans->journal_res.seq);
 		} else if (!i->key_cache_already_flushed)
 			bch2_btree_insert_key_cached(trans, flags, i);
 		else {

fs/bcachefs/btree_types.h

@@ -356,7 +356,6 @@ struct btree_insert_entry {
 	u8			old_btree_u64s;
 	struct bkey_i		*k;
 	struct btree_path	*path;
-	u64			seq;
 	/* key being overwritten: */
 	struct bkey		old_k;
 	const struct bch_val	*old_v;

fs/bcachefs/btree_update.c

@@ -381,21 +381,12 @@ bch2_trans_update_by_path(struct btree_trans *trans, struct btree_path *path,
 {
 	struct bch_fs *c = trans->c;
 	struct btree_insert_entry *i, n;
-	u64 seq = 0;
 	int cmp;
 
 	EBUG_ON(!path->should_be_locked);
 	EBUG_ON(trans->nr_updates >= BTREE_ITER_MAX);
 	EBUG_ON(!bpos_eq(k->k.p, path->pos));
 
-	/*
-	 * The transaction journal res hasn't been allocated at this point.
-	 * That occurs at commit time. Reuse the seq field to pass in the seq
-	 * of a prejournaled key.
-	 */
-	if (flags & BTREE_UPDATE_PREJOURNAL)
-		seq = trans->journal_res.seq;
-
 	n = (struct btree_insert_entry) {
 		.flags		= flags,
 		.bkey_type	= __btree_node_type(path->level, path->btree_id),
@@ -404,7 +395,6 @@ bch2_trans_update_by_path(struct btree_trans *trans, struct btree_path *path,
 		.cached		= path->cached,
 		.path		= path,
 		.k		= k,
-		.seq		= seq,
 		.ip_allocated	= ip,
 	};
 
@@ -432,7 +422,6 @@ bch2_trans_update_by_path(struct btree_trans *trans, struct btree_path *path,
 		i->cached	= n.cached;
 		i->k		= n.k;
 		i->path		= n.path;
-		i->seq		= n.seq;
 		i->ip_allocated	= n.ip_allocated;
 	} else {
 		array_insert_item(trans->updates, trans->nr_updates,
@@ -543,18 +532,6 @@ int __must_check bch2_trans_update(struct btree_trans *trans, struct btree_iter
 	return bch2_trans_update_by_path(trans, path, k, flags, _RET_IP_);
 }
 
-/*
- * Add a transaction update for a key that has already been journaled.
- */
-int __must_check bch2_trans_update_seq(struct btree_trans *trans, u64 seq,
-				       struct btree_iter *iter, struct bkey_i *k,
-				       enum btree_update_flags flags)
-{
-	trans->journal_res.seq = seq;
-	return bch2_trans_update(trans, iter, k, flags|BTREE_UPDATE_NOJOURNAL|
-						 BTREE_UPDATE_PREJOURNAL);
-}
-
 static noinline int bch2_btree_insert_clone_trans(struct btree_trans *trans,
 						  enum btree_id btree,
 						  struct bkey_i *k)

fs/bcachefs/btree_write_buffer.c

@@ -78,12 +78,15 @@ static int bch2_btree_write_buffer_flush_one(struct btree_trans *trans,
 	}
 	return 0;
 trans_commit:
-	return  bch2_trans_update_seq(trans, wb->journal_seq, iter, &wb->k,
-				      BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
+	trans->journal_res.seq = wb->journal_seq;
+
+	return  bch2_trans_update(trans, iter, &wb->k,
+				  BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
 		bch2_trans_commit(trans, NULL, NULL,
 				  commit_flags|
 				  BTREE_INSERT_NOCHECK_RW|
 				  BTREE_INSERT_NOFAIL|
+				  BTREE_INSERT_JOURNAL_REPLAY|
 				  BTREE_INSERT_JOURNAL_RECLAIM);
 }
 
@@ -127,9 +130,11 @@ btree_write_buffered_insert(struct btree_trans *trans,
 	bch2_trans_iter_init(trans, &iter, wb->btree, bkey_start_pos(&wb->k.k),
 			     BTREE_ITER_CACHED|BTREE_ITER_INTENT);
 
+	trans->journal_res.seq = wb->journal_seq;
+
 	ret   = bch2_btree_iter_traverse(&iter) ?:
-		bch2_trans_update_seq(trans, wb->journal_seq, &iter, &wb->k,
-				      BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		bch2_trans_update(trans, &iter, &wb->k,
+				  BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
 }
@@ -262,6 +267,7 @@ int __bch2_btree_write_buffer_flush(struct btree_trans *trans, unsigned commit_f
 		ret = commit_do(trans, NULL, NULL,
 				commit_flags|
 				BTREE_INSERT_NOFAIL|
+				BTREE_INSERT_JOURNAL_REPLAY|
 				BTREE_INSERT_JOURNAL_RECLAIM,
 				btree_write_buffered_insert(trans, i));
 		if (bch2_fs_fatal_err_on(ret, c, "%s: insert error %s", __func__, bch2_err_str(ret)))