diff --git a/core/src/main/java/hudson/lifecycle/ZFSInstaller.java b/core/src/main/java/hudson/lifecycle/ZFSInstaller.java
index ce9ec4b07eba3e316f3b8cca4bd5afbda1da6f9f..a23670c4bc64044f5c99689fc92d5133b648e2af 100644
--- a/core/src/main/java/hudson/lifecycle/ZFSInstaller.java
+++ b/core/src/main/java/hudson/lifecycle/ZFSInstaller.java
@@ -152,7 +152,8 @@ public class ZFSInstaller extends AdministrativeMonitor implements Serializable
     private String createZfsFileSystem(final TaskListener listener, String rootUsername, String rootPassword) throws IOException, InterruptedException, ZFSException {
         // capture the UID that Hudson runs under
         // so that we can allow this user to do everything on this new partition
-        int uid = LIBC.geteuid();
+        final int uid = LIBC.geteuid();
+        final int gid = LIBC.getegid();
         passwd pwd = LIBC.getpwuid(uid);
         if(pwd==null)
             throw new IOException("Failed to obtain the current user information for "+uid);
@@ -178,6 +179,14 @@ public class ZFSInstaller extends AdministrativeMonitor implements Serializable
                 out.println("Creating "+name);
                 ZFSFileSystem hudson = zfs.create(name, ZFSFileSystem.class);
 
+                // mount temporarily to set the owner right
+                File dir = Util.createTempDir();
+                hudson.setMountPoint(dir);
+                hudson.mount();
+                if(LIBC.chown(dir.getPath(),uid,gid)!=0)
+                    throw new IOException("Failed to chown "+dir);
+                hudson.unmount();
+
                 try {
                     hudson.setProperty("hudson:managed-by","hudson"); // mark this file system as "managed by Hudson"
 
@@ -286,7 +295,7 @@ public class ZFSInstaller extends AdministrativeMonitor implements Serializable
                     }
 
                     // re-exec with the system property to indicate where to migrate the data to.
-                    // the 2nd phase starts in the init method.
+                    // the 2nd phase is implemented in the migrate method.
                     JavaVMArguments args = JavaVMArguments.current();
                     args.setSystemProperty(ZFSInstaller.class.getName()+".migrate",datasetName);
                     Daemon.selfExec(args);
diff --git a/core/src/main/java/hudson/util/jna/GNUCLibrary.java b/core/src/main/java/hudson/util/jna/GNUCLibrary.java
index 79db6d75089ab924b6a4b2c54dbb818656720919..56e08a5631bb43a6fec00a4cdbe7c118be84b1bd 100644
--- a/core/src/main/java/hudson/util/jna/GNUCLibrary.java
+++ b/core/src/main/java/hudson/util/jna/GNUCLibrary.java
@@ -42,6 +42,7 @@ public interface GNUCLibrary extends Library {
     int umask(int mask);
     int getpid();
     int geteuid();
+    int getegid();
     int getppid();
     int chdir(String dir);
     int getdtablesize();
@@ -61,6 +62,8 @@ public interface GNUCLibrary extends Library {
     static final int F_GETFD = 1;
     static final int F_SETFD = 2;
     static final int FD_CLOEXEC = 1;
+
+    int chown(String fileName, int uid, int gid);
     
 
     // this is listed in http://developer.apple.com/DOCUMENTATION/Darwin/Reference/ManPages/man3/sysctlbyname.3.html