bcachefs: Suppress -EROFS messages when shutting down

This isn't actually an error condition, this just indicates a normal
shutdown - no reason for these to be in the log.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_gc.c

@@ -1976,10 +1976,10 @@ int bch2_gc_gens(struct bch_fs *c)
 					NULL, NULL,
 					BTREE_INSERT_NOFAIL,
 				gc_btree_gens_key(&trans, &iter, k));
-			if (ret) {
+			if (ret && ret != -EROFS)
 				bch_err(c, "error recalculating oldest_gen: %s", bch2_err_str(ret));
+			if (ret)
 				goto err;
-			}
 		}
 
 	ret = for_each_btree_key_commit(&trans, iter, BTREE_ID_alloc,
@@ -1989,10 +1989,10 @@ int bch2_gc_gens(struct bch_fs *c)
 			NULL, NULL,
 			BTREE_INSERT_NOFAIL,
 		bch2_alloc_write_oldest_gen(&trans, &iter, k));
-	if (ret) {
+	if (ret && ret != -EROFS)
 		bch_err(c, "error writing oldest_gen: %s", bch2_err_str(ret));
+	if (ret)
 		goto err;
-	}
 
 	c->gc_gens_btree	= 0;
 	c->gc_gens_pos		= POS_MIN;

fs/bcachefs/io.c

@@ -675,15 +675,17 @@ static void __bch2_write_index(struct bch_write_op *op)
 
 		op->written += sectors_start - keylist_sectors(keys);
 
-		if (ret) {
+		if (ret && !bch2_err_matches(ret, EROFS)) {
 			struct bkey_i *k = bch2_keylist_front(&op->insert_keys);
 
 			bch_err_inum_offset_ratelimited(c,
 				k->k.p.inode, k->k.p.offset << 9,
 				"write error while doing btree update: %s",
 				bch2_err_str(ret));
-			goto err;
 		}
+
+		if (ret)
+			goto err;
 	}
 out:
 	/* If some a bucket wasn't written, we can't erasure code it: */

fs/bcachefs/movinggc.c

@@ -319,7 +319,7 @@ static int bch2_copygc(struct bch_fs *c)
 			     writepoint_ptr(&c->copygc_write_point),
 			     false,
 			     copygc_pred, NULL);
-	if (ret < 0)
+	if (ret < 0 && ret != -EROFS)
 		bch_err(c, "error from bch2_move_data() in copygc: %s", bch2_err_str(ret));
 	if (ret)
 		return ret;