commit c2cf5f1c2abc81d607abe34bf5dc4c615a9b8b4d
Author: Daniel P. Berrange <berrange@redhat.com>
Date:   Thu May 16 18:47:07 2013 +0100

    Fix failure to detect missing cgroup partitions
    
    Change bbe97ae968eba60b71e0066d49f9fc909966d9d6 caused the
    QEMU driver to ignore ENOENT errors from cgroups, in order
    to cope with missing /proc/cgroups. This is not good though
    because many other things can cause ENOENT and should not
    be ignored. The callers expect to see ENXIO when cgroups
    are not present, so adjust the code to report that errno
    when /proc/cgroups is missing
    
    Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

Index: libvirt-1.0.5/src/qemu/qemu_cgroup.c
===================================================================
--- libvirt-1.0.5.orig/src/qemu/qemu_cgroup.c
+++ libvirt-1.0.5/src/qemu/qemu_cgroup.c
@@ -415,8 +415,7 @@ int qemuInitCgroup(virQEMUDriverPtr driv
         if (rc != 0) {
             if (rc == -ENXIO ||
                 rc == -EPERM ||
-                rc == -EACCES ||
-                rc == -ENOENT) { /* No cgroups mounts == success */
+                rc == -EACCES) { /* No cgroups mounts == success */
                 VIR_DEBUG("No cgroups present/configured/accessible, ignoring error");
                 goto done;
             }
Index: libvirt-1.0.5/src/util/vircgroup.c
===================================================================
--- libvirt-1.0.5.orig/src/util/vircgroup.c
+++ libvirt-1.0.5/src/util/vircgroup.c
@@ -1110,8 +1110,13 @@ static int virCgroupPartitionNeedsEscapi
         path[0] == '.')
         return 1;
 
-    if (!(fp = fopen("/proc/cgroups", "r")))
+    if (!(fp = fopen("/proc/cgroups", "r"))) {
+        /* The API contract is that we return ENXIO
+         * if cgroups are not available on a host */
+        if (errno == ENOENT)
+            errno = ENXIO;
         return -errno;
+    }
 
     /*
      * Data looks like this: