From fc3981ea5c10fb21cae6d6a8e78755be5b169999 Mon Sep 17 00:00:00 2001
From: Michael Crosby <crosbymichael@gmail.com>
Date: Mon, 23 Mar 2015 12:14:03 -0700
Subject: [PATCH 1/2] Revert "cgroups: only return path when subsystem really
 mounted"

This reverts commit 606d9064b0a6abd82da3731fda9f1558ec1f153c.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
---
 cgroups/fs/apply_raw.go | 6 ------
 cgroups/fs/blkio.go     | 8 ++------
 cgroups/fs/cpu.go       | 6 +-----
 cgroups/fs/devices.go   | 6 +-----
 cgroups/fs/freezer.go   | 8 ++------
 cgroups/fs/memory.go    | 9 +++------
 6 files changed, 9 insertions(+), 34 deletions(-)

diff --git a/cgroups/fs/apply_raw.go b/cgroups/fs/apply_raw.go
index 5cb8467c..2fc95421 100644
--- a/cgroups/fs/apply_raw.go
+++ b/cgroups/fs/apply_raw.go
@@ -235,12 +235,6 @@ func (raw *data) parent(subsystem string) (string, error) {
 }
 
 func (raw *data) path(subsystem string) (string, error) {
-	_, err := cgroups.FindCgroupMountpoint(subsystem)
-	// If we didn't mount the subsystem, there is no point we make the path.
-	if err != nil {
-		return "", err
-	}
-
 	// If the cgroup name/path is absolute do not look relative to the cgroup of the init process.
 	if filepath.IsAbs(raw.cgroup) {
 		return filepath.Join(raw.root, subsystem, raw.cgroup), nil
diff --git a/cgroups/fs/blkio.go b/cgroups/fs/blkio.go
index 01da5d7f..8e132643 100644
--- a/cgroups/fs/blkio.go
+++ b/cgroups/fs/blkio.go
@@ -17,12 +17,8 @@ type BlkioGroup struct {
 
 func (s *BlkioGroup) Apply(d *data) error {
 	dir, err := d.join("blkio")
-	if err != nil {
-		if cgroups.IsNotFound(err) {
-			return nil
-		} else {
-			return err
-		}
+	if err != nil && !cgroups.IsNotFound(err) {
+		return err
 	}
 
 	if err := s.Set(dir, d.c); err != nil {
diff --git a/cgroups/fs/cpu.go b/cgroups/fs/cpu.go
index 42386fd8..1fbf7b15 100644
--- a/cgroups/fs/cpu.go
+++ b/cgroups/fs/cpu.go
@@ -18,11 +18,7 @@ func (s *CpuGroup) Apply(d *data) error {
 	// on a container basis
 	dir, err := d.join("cpu")
 	if err != nil {
-		if cgroups.IsNotFound(err) {
-			return nil
-		} else {
-			return err
-		}
+		return err
 	}
 
 	if err := s.Set(dir, d.c); err != nil {
diff --git a/cgroups/fs/devices.go b/cgroups/fs/devices.go
index fab8323e..16e00b1c 100644
--- a/cgroups/fs/devices.go
+++ b/cgroups/fs/devices.go
@@ -11,11 +11,7 @@ type DevicesGroup struct {
 func (s *DevicesGroup) Apply(d *data) error {
 	dir, err := d.join("devices")
 	if err != nil {
-		if cgroups.IsNotFound(err) {
-			return nil
-		} else {
-			return err
-		}
+		return err
 	}
 
 	if err := s.Set(dir, d.c); err != nil {
diff --git a/cgroups/fs/freezer.go b/cgroups/fs/freezer.go
index 5e08e053..fc8241d1 100644
--- a/cgroups/fs/freezer.go
+++ b/cgroups/fs/freezer.go
@@ -13,12 +13,8 @@ type FreezerGroup struct {
 
 func (s *FreezerGroup) Apply(d *data) error {
 	dir, err := d.join("freezer")
-	if err != nil {
-		if cgroups.IsNotFound(err) {
-			return nil
-		} else {
-			return err
-		}
+	if err != nil && !cgroups.IsNotFound(err) {
+		return err
 	}
 
 	if err := s.Set(dir, d.c); err != nil {
diff --git a/cgroups/fs/memory.go b/cgroups/fs/memory.go
index 68e930fd..b99f8168 100644
--- a/cgroups/fs/memory.go
+++ b/cgroups/fs/memory.go
@@ -16,12 +16,9 @@ type MemoryGroup struct {
 
 func (s *MemoryGroup) Apply(d *data) error {
 	dir, err := d.join("memory")
-	if err != nil {
-		if cgroups.IsNotFound(err) {
-			return nil
-		} else {
-			return err
-		}
+	// only return an error for memory if it was specified
+	if err != nil && (d.c.Memory != 0 || d.c.MemoryReservation != 0 || d.c.MemorySwap != 0) {
+		return err
 	}
 	defer func() {
 		if err != nil {

From c5eef904604b7e22083927bb99ea0c196d4cb8b9 Mon Sep 17 00:00:00 2001
From: Michael Crosby <crosbymichael@gmail.com>
Date: Mon, 23 Mar 2015 12:20:18 -0700
Subject: [PATCH 2/2] Add back check for mountpoint to return consistent error

Adding this check here allows a nice error displaying that the specified
cgroup subsystem is not mounted.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
---
 cgroups/fs/apply_raw.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/cgroups/fs/apply_raw.go b/cgroups/fs/apply_raw.go
index 2fc95421..5cb8467c 100644
--- a/cgroups/fs/apply_raw.go
+++ b/cgroups/fs/apply_raw.go
@@ -235,6 +235,12 @@ func (raw *data) parent(subsystem string) (string, error) {
 }
 
 func (raw *data) path(subsystem string) (string, error) {
+	_, err := cgroups.FindCgroupMountpoint(subsystem)
+	// If we didn't mount the subsystem, there is no point we make the path.
+	if err != nil {
+		return "", err
+	}
+
 	// If the cgroup name/path is absolute do not look relative to the cgroup of the init process.
 	if filepath.IsAbs(raw.cgroup) {
 		return filepath.Join(raw.root, subsystem, raw.cgroup), nil