btrfs-progs: fix corruption when doing mkfs.btrfs with -O ^no-holes

Commit 44b83ff introduces a bug: when we encountered a hole in the
source file, we're creating a explicit file extent.

But as we're zero-initializing the struct btrfs_file_extent_item, we're
setting its type to BTRFS_FILE_EXTENT_INLINE. Fix this by forcing it to
be BTRFS_FILE_EXTENT_REG.

Signed-off-by: Mark Harmstone <mark@harmstone.com>

Author: maharmstone

mkfs/rootdir.c

@@ -819,6 +819,7 @@ static int add_file_item_extent(struct btrfs_trans_handle *trans,
 		 */
 		const u64 length = min_t(u64, next - file_pos, SZ_1G);
 
+		btrfs_set_stack_file_extent_type(&stack_fi, BTRFS_FILE_EXTENT_REG);
 		btrfs_set_stack_file_extent_num_bytes(&stack_fi, length);
 		btrfs_set_stack_file_extent_ram_bytes(&stack_fi, length);
 		ret = btrfs_insert_file_extent(trans, root, objectid, file_pos, &stack_fi);