bcachefs: More minor smatch fixes

- fix a few uninitialized return values
 - return a proper error code in lookup_lostfound()

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

fs/bcachefs/btree_update.c

@@ -124,7 +124,7 @@ int __bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
 	struct bkey_s_c old_k, new_k;
 	snapshot_id_list s;
 	struct bkey_i *update;
-	int ret;
+	int ret = 0;
 
 	if (!bch2_snapshot_has_children(c, old_pos.snapshot))
 		return 0;

fs/bcachefs/errcode.h

@@ -99,6 +99,7 @@
 	x(ENOENT,			ENOENT_str_hash_set_must_replace)	\
 	x(ENOENT,			ENOENT_inode)				\
 	x(ENOENT,			ENOENT_not_subvol)			\
+	x(ENOENT,			ENOENT_not_directory)			\
 	x(ENOENT,			ENOENT_directory_dead)			\
 	x(ENOENT,			ENOENT_subvolume)			\
 	x(ENOENT,			ENOENT_snapshot_tree)			\

fs/bcachefs/fsck.c

@@ -281,7 +281,7 @@ static int lookup_lostfound(struct btree_trans *trans, u32 subvol,
 
 	if (d_type != DT_DIR) {
 		bch_err(c, "error looking up lost+found: not a directory");
-		return ret;
+		return -BCH_ERR_ENOENT_not_directory;
 	}
 
 	/*

fs/bcachefs/io_write.c

@@ -930,7 +930,7 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 	do {
 		struct bch_extent_crc_unpacked crc = { 0 };
 		struct bversion version = op->version;
-		size_t dst_len, src_len;
+		size_t dst_len = 0, src_len = 0;
 
 		if (page_alloc_failed &&
 		    dst->bi_iter.bi_size  < (wp->sectors_free << 9) &&

fs/bcachefs/move.c

@@ -627,7 +627,7 @@ int bch2_move_data(struct bch_fs *c,
 {
 	struct moving_context ctxt;
 	enum btree_id id;
-	int ret;
+	int ret = 0;
 
 	bch2_moving_ctxt_init(&ctxt, c, rate, stats, wp, wait_on_copygc);
 

fs/bcachefs/super-io.c

@@ -185,7 +185,7 @@ int bch2_sb_realloc(struct bch_sb_handle *sb, unsigned u64s)
 	if (sb->sb && sb->buffer_size >= new_buffer_size)
 		return 0;
 
-	if (sb->have_layout) {
+	if (sb->sb && sb->have_layout) {
 		u64 max_bytes = 512 << sb->sb->layout.sb_max_size_bits;
 
 		if (new_bytes > max_bytes) {