f2fs: allow set compression option of files without blocks

Files created by truncate have a size but no blocks, so
they can be allowed to set compression option.

Fixes: e1e8debe ("f2fs: add F2FS_IOC_SET_COMPRESS_OPTION ioctl")
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -3941,7 +3941,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg)
 		goto out;
 	}
 
-	if (inode->i_size != 0) {
+	if (F2FS_HAS_BLOCKS(inode)) {
 		ret = -EFBIG;
 		goto out;
 	}