Merge pull request #68 from filecoin-project/fix/darwin

Fix build on osx

fsutil/dealloc_other.go

@@ -13,5 +13,5 @@ var log = logging.Logger("fsutil")
 func Deallocate(file *os.File, offset int64, length int64) error {
 	log.Warnf("deallocating space not supported")
 
-	return err
+	return nil
 }

fsutil/filesize_unix.go

@@ -20,6 +20,6 @@ func FileSize(path string) (SizeInfo, error) {
 	// NOTE: stat.Blocks is in 512B blocks, NOT in stat.Blksize
 	//  See https://www.gnu.org/software/libc/manual/html_node/Attribute-Meanings.html
 	return SizeInfo{
-		stat.Blocks * 512,
+		int64(stat.Blocks) * 512,
 	}, nil
 }

fsutil/statfs_unix.go

@@ -13,7 +13,7 @@ func Statfs(path string) (FsStat, error) {
 	}
 
 	return FsStat{
-		Capacity:  int64(stat.Blocks) * stat.Bsize,
-		Available: int64(stat.Bavail) * stat.Bsize,
+		Capacity:  int64(stat.Blocks) * int64(stat.Bsize),
+		Available: int64(stat.Bavail) * int64(stat.Bsize),
 	}, nil
 }