bcachefs: journal_replay_entry_early() checks for nonexistent device

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

fs/bcachefs/recovery.c

@@ -373,14 +373,17 @@ static int journal_replay_entry_early(struct bch_fs *c,
 	case BCH_JSET_ENTRY_dev_usage: {
 		struct jset_entry_dev_usage *u =
 			container_of(entry, struct jset_entry_dev_usage, entry);
-		struct bch_dev *ca = bch2_dev_bkey_exists(c, le32_to_cpu(u->dev));
-		unsigned i, nr_types = jset_entry_dev_usage_nr_types(u);
-
-		for (i = 0; i < min_t(unsigned, nr_types, BCH_DATA_NR); i++) {
-			ca->usage_base->d[i].buckets	= le64_to_cpu(u->d[i].buckets);
-			ca->usage_base->d[i].sectors	= le64_to_cpu(u->d[i].sectors);
-			ca->usage_base->d[i].fragmented	= le64_to_cpu(u->d[i].fragmented);
-		}
+		unsigned nr_types = jset_entry_dev_usage_nr_types(u);
+
+		rcu_read_lock();
+		struct bch_dev *ca = bch2_dev_rcu(c, le32_to_cpu(u->dev));
+		if (ca)
+			for (unsigned i = 0; i < min_t(unsigned, nr_types, BCH_DATA_NR); i++) {
+				ca->usage_base->d[i].buckets	= le64_to_cpu(u->d[i].buckets);
+				ca->usage_base->d[i].sectors	= le64_to_cpu(u->d[i].sectors);
+				ca->usage_base->d[i].fragmented	= le64_to_cpu(u->d[i].fragmented);
+			}
+		rcu_read_unlock();
 
 		break;
 	}