From 27a92f94c8bdaa660b230c364479442534cdd5b9 Mon Sep 17 00:00:00 2001
From: Ganesh Maharaj Mahalingam <ganesh.mahalingam@intel.com>
Date: Tue, 5 Mar 2019 13:23:00 -0800
Subject: [PATCH] runtime: Fix rootfs mount assumptions

This patch fixes the issue where various version of snapshotters,
overlay, block based graphdriver, containerd-shim-v2 overlay, block
based snapshotters mount & create rootfs differently and kata should be
able to handle them all.

The current version of the code always assumes that a folder named
'rootfs' exists within the mount device and that is the path the
container should start at. This patch checks the existing mount point
and if it is the same as the rootFs passed to the container, we no
longer add a suffix to the container's rootfs path.

Fixes: #1325

Signed-off-by: Ganesh Maharaj Mahalingam <ganesh.mahalingam@intel.com>
Co-Authored-by: Manohar Castelino <manohar.r.castelino@intel.com>
---
 virtcontainers/container.go  | 6 ++++++
 virtcontainers/kata_agent.go | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/virtcontainers/container.go b/virtcontainers/container.go
index 5408d858b..f11fe997b 100644
--- a/virtcontainers/container.go
+++ b/virtcontainers/container.go
@@ -276,6 +276,7 @@ type Container struct {
 	runPath       string
 	configPath    string
 	containerPath string
+	rootfsSuffix  string
 
 	state types.State
 
@@ -640,6 +641,7 @@ func newContainer(sandbox *Sandbox, contConfig ContainerConfig) (*Container, err
 		runPath:       store.ContainerRuntimeRootPath(sandbox.id, contConfig.ID),
 		configPath:    store.ContainerConfigurationRootPath(sandbox.id, contConfig.ID),
 		containerPath: filepath.Join(sandbox.id, contConfig.ID),
+		rootfsSuffix:  "rootfs",
 		state:         types.State{},
 		process:       Process{},
 		mounts:        contConfig.Mounts,
@@ -1131,6 +1133,10 @@ func (c *Container) hotplugDrive() error {
 		return nil
 	}
 
+	if dev.mountPoint == c.rootFs {
+		c.rootfsSuffix = ""
+	}
+
 	// If device mapper device, then fetch the full path of the device
 	devicePath, fsType, err := getDevicePathAndFsType(dev.mountPoint)
 	if err != nil {
diff --git a/virtcontainers/kata_agent.go b/virtcontainers/kata_agent.go
index f07b89106..bec20373e 100644
--- a/virtcontainers/kata_agent.go
+++ b/virtcontainers/kata_agent.go
@@ -986,7 +986,7 @@ func (k *kataAgent) createContainer(sandbox *Sandbox, c *Container) (p *Process,
 
 	// This is the guest absolute root path for that container.
 	rootPathParent := filepath.Join(kataGuestSharedDir, c.id)
-	rootPath := filepath.Join(rootPathParent, rootfsDir)
+	rootPath := filepath.Join(rootPathParent, c.rootfsSuffix)
 
 	// In case the container creation fails, the following defer statement
 	// takes care of rolling back actions previously performed.