diff --git a/CHANGELOG.md b/CHANGELOG.md
index e1ab7f3c4c..44a53a50d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased] - ReleaseDate
+### Added
+### Changed
+### Fixed
+
+- Fixed the build for OpenBSD
+  (#[1168](https://github.com/nix-rust/nix/pull/1168))
+
+### Removed
 
 ## [0.16.0] - 1 December 2019
 ### Added
diff --git a/src/sys/statfs.rs b/src/sys/statfs.rs
index c71b5767ae..f463400eae 100644
--- a/src/sys/statfs.rs
+++ b/src/sys/statfs.rs
@@ -106,11 +106,17 @@ impl Statfs {
     }
 
     /// Optimal transfer block size
-    #[cfg(any(target_os = "ios", target_os = "macos", target_os = "openbsd"))]
+    #[cfg(any(target_os = "ios", target_os = "macos"))]
     pub fn optimal_transfer_size(&self) -> i32 {
         self.0.f_iosize
     }
 
+    /// Optimal transfer block size
+    #[cfg(target_os = "openbsd")]
+    pub fn optimal_transfer_size(&self) -> u32 {
+        self.0.f_iosize
+    }
+
     /// Optimal transfer block size
     #[cfg(all(target_os = "linux", target_arch = "s390x"))]
     pub fn optimal_transfer_size(&self) -> u32 {
@@ -118,7 +124,10 @@ impl Statfs {
     }
 
     /// Optimal transfer block size
-    #[cfg(all(target_os = "linux", target_env = "musl"))]
+    #[cfg(any(
+        target_os = "android",
+        all(target_os = "linux", target_env = "musl")
+    ))]
     pub fn optimal_transfer_size(&self) -> libc::c_ulong {
         self.0.f_bsize
     }
@@ -129,12 +138,6 @@ impl Statfs {
         self.0.f_bsize
     }
 
-    /// Optimal transfer block size
-    #[cfg(target_os = "android")]
-    pub fn optimal_transfer_size(&self) -> libc::c_ulong {
-        self.0.f_bsize
-    }
-
     /// Optimal transfer block size
     #[cfg(target_os = "dragonfly")]
     pub fn optimal_transfer_size(&self) -> libc::c_long {
@@ -375,7 +378,13 @@ impl Statfs {
     }
 
     /// Free file nodes in filesystem
-    #[cfg(any(target_os = "ios", target_os = "macos", target_os = "android"))]
+    #[cfg(any(
+            target_os = "android",
+            target_os = "ios",
+            all(target_os = "linux", target_env = "musl"),
+            target_os = "macos",
+            target_os = "openbsd"
+    ))]
     pub fn files_free(&self) -> u64 {
         self.0.f_ffree
     }
@@ -387,17 +396,11 @@ impl Statfs {
     }
 
     /// Free file nodes in filesystem
-    #[cfg(any(target_os = "freebsd", target_os = "openbsd"))]
+    #[cfg(target_os = "freebsd")]
     pub fn files_free(&self) -> i64 {
         self.0.f_ffree
     }
 
-    /// Free file nodes in filesystem
-    #[cfg(all(target_os = "linux", target_env = "musl"))]
-    pub fn files_free(&self) -> u64 {
-        self.0.f_ffree
-    }
-
     /// Free file nodes in filesystem
     #[cfg(not(any(
         target_os = "ios",