bcachefs: Add a mechanism for passing extra journal entries to bch2_trans_commit()

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

fs/bcachefs/btree_iter.c

@@ -2153,6 +2153,9 @@ void bch2_trans_reset(struct btree_trans *trans, unsigned flags)
 	trans->nr_updates2		= 0;
 	trans->mem_top			= 0;
 
+	trans->extra_journal_entries	= NULL;
+	trans->extra_journal_entry_u64s	= 0;
+
 	if (trans->fs_usage_deltas) {
 		trans->fs_usage_deltas->used = 0;
 		memset((void *) trans->fs_usage_deltas +

fs/bcachefs/btree_types.h

@@ -308,6 +308,9 @@ struct btree_trans {
 	struct btree_insert_entry *updates2;
 
 	/* update path: */
+	struct jset_entry	*extra_journal_entries;
+	unsigned		extra_journal_entry_u64s;
+
 	struct journal_res	journal_res;
 	struct journal_preres	journal_preres;
 	u64			*journal_seq;

fs/bcachefs/btree_update_leaf.c

@@ -413,6 +413,16 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
 			goto err;
 	}
 
+	if (unlikely(trans->extra_journal_entry_u64s)) {
+		memcpy_u64s_small(bch2_journal_reservation_entry(&c->journal,
+								 &trans->journal_res),
+				  trans->extra_journal_entries,
+				  trans->extra_journal_entry_u64s);
+
+		trans->journal_res.offset	+= trans->extra_journal_entry_u64s;
+		trans->journal_res.u64s		-= trans->extra_journal_entry_u64s;
+	}
+
 	/*
 	 * Not allowed to fail after we've gotten our journal reservation - we
 	 * have to use it:
@@ -800,7 +810,7 @@ int __bch2_trans_commit(struct btree_trans *trans)
 
 	memset(&trans->journal_preres, 0, sizeof(trans->journal_preres));
 
-	trans->journal_u64s		= 0;
+	trans->journal_u64s		= trans->extra_journal_entry_u64s;
 	trans->journal_preres_u64s	= 0;
 
 	if (!(trans->flags & BTREE_INSERT_NOCHECK_RW) &&

fs/bcachefs/journal.h

@@ -199,13 +199,18 @@ bch2_journal_add_entry_noreservation(struct journal_buf *buf, size_t u64s)
 	return entry;
 }
 
+static inline struct jset_entry *
+bch2_journal_reservation_entry(struct journal *j, struct journal_res *res)
+{
+	return vstruct_idx(j->buf[res->idx].data, res->offset);
+}
+
 static inline void bch2_journal_add_entry(struct journal *j, struct journal_res *res,
 					  unsigned type, enum btree_id id,
 					  unsigned level,
 					  const void *data, unsigned u64s)
 {
-	struct journal_buf *buf = &j->buf[res->idx];
-	struct jset_entry *entry = vstruct_idx(buf->data, res->offset);
+	struct jset_entry *entry = bch2_journal_reservation_entry(j, res);
 	unsigned actual = jset_u64s(u64s);
 
 	EBUG_ON(!res->ref);
@@ -221,7 +226,7 @@ static inline void bch2_journal_add_entry(struct journal *j, struct journal_res
 	entry->pad[0]	= 0;
 	entry->pad[1]	= 0;
 	entry->pad[2]	= 0;
-	memcpy_u64s(entry->_data, data, u64s);
+	memcpy_u64s_small(entry->_data, data, u64s);
 }
 
 static inline void bch2_journal_add_keys(struct journal *j, struct journal_res *res,