bcachefs: Increase default journal size

The default was 1/256th of the device and capped at 512MB, which is
fairly tiny these days.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/journal.c

@@ -913,14 +913,17 @@ int bch2_dev_journal_alloc(struct bch_dev *ca)
 	if (dynamic_fault("bcachefs:add:journal_alloc"))
 		return -ENOMEM;
 
+	/* 1/128th of the device by default: */
+	nr = ca->mi.nbuckets >> 7;
+
 	/*
-	 * clamp journal size to 1024 buckets or 512MB (in sectors), whichever
+	 * clamp journal size to 8192 buckets or 8GB (in sectors), whichever
 	 * is smaller:
 	 */
-	nr = clamp_t(unsigned, ca->mi.nbuckets >> 8,
+	nr = clamp_t(unsigned, nr,
 		     BCH_JOURNAL_BUCKETS_MIN,
-		     min(1 << 10,
-			 (1 << 20) / ca->mi.bucket_size));
+		     min(1 << 13,
+			 (1 << 24) / ca->mi.bucket_size));
 
 	return __bch2_set_nr_journal_buckets(ca, nr, true, NULL);
 }