Allow existing setups to continue using d_type

thaJeztah · thaJeztah · commit 0a4e793a3da9 · 2017-12-04T18:41:25.000-08:00
Even though it's highly discouraged, there are existing
installs that are running overlay/overlay2 on filesystems
without d_type support.

This patch allows the daemon to start in such cases, instead of
refusing to start without an option to override.

For fresh installs, backing filesystems without d_type support
will still cause the overlay/overlay2 drivers to be marked as
"unsupported", and skipped during the automatic selection.

This feature is only to keep backward compatibility, but
will be removed at some point.

Signed-off-by: Sebastiaan van Stijn &lt;github@gone.nl&gt;
diff --git a/daemon/graphdriver/driver.go b/daemon/graphdriver/driver.go
@@ -277,6 +277,18 @@ func scanPriorDrivers(root string) map[string]bool {
 	return driversMap
 }
 
+// IsInitialized checks if the driver's home-directory exists and is non-empty.
+func IsInitialized(driverHome string) bool {
+	_, err := os.Stat(driverHome)
+	if os.IsNotExist(err) {
+		return false
+	}
+	if err != nil {
+		logrus.Warnf("graphdriver.IsInitialized: stat failed: %v", err)
+	}
+	return !isEmptyDir(driverHome)
+}
+
 // isEmptyDir checks if a directory is empty. It is used to check if prior
 // storage-driver directories exist. If an error occurs, it also assumes the
 // directory is not empty (which preserves the behavior _before_ this check
diff --git a/daemon/graphdriver/overlay/overlay.go b/daemon/graphdriver/overlay/overlay.go
@@ -148,7 +148,11 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, err
 	}
 	if !supportsDType {
-		return nil, overlayutils.ErrDTypeNotSupported("overlay", backingFs)
+		if !graphdriver.IsInitialized(home) {
+			return nil, overlayutils.ErrDTypeNotSupported("overlay", backingFs)
+		}
+		// allow running without d_type only for existing setups (#27443)
+		logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay", backingFs))
 	}
 
 	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
diff --git a/daemon/graphdriver/overlay2/overlay.go b/daemon/graphdriver/overlay2/overlay.go
@@ -184,7 +184,11 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, err
 	}
 	if !supportsDType {
-		return nil, overlayutils.ErrDTypeNotSupported("overlay2", backingFs)
+		if !graphdriver.IsInitialized(home) {
+			return nil, overlayutils.ErrDTypeNotSupported("overlay2", backingFs)
+		}
+		// allow running without d_type only for existing setups (#27443)
+		logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay2", backingFs))
 	}
 
 	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)

Original file line number	Diff line number	Diff line change
`@@ -148,7 +148,11 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap`
`148`	`148`	`return nil, err`
`149`	`149`	`}`
`150`	`150`	`if !supportsDType {`
`151`		`- return nil, overlayutils.ErrDTypeNotSupported("overlay", backingFs)`
	`151`	`+ if !graphdriver.IsInitialized(home) {`
	`152`	`+ return nil, overlayutils.ErrDTypeNotSupported("overlay", backingFs)`
	`153`	`+ }`
	`154`	`+ // allow running without d_type only for existing setups (#27443)`
	`155`	`+ logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay", backingFs))`
`152`	`156`	`}`
`153`	`157`
`154`	`158`	`rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)`
Original file line number	Diff line number	Diff line change
`@@ -184,7 +184,11 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap`
`184`	`184`	`return nil, err`
`185`	`185`	`}`
`186`	`186`	`if !supportsDType {`
`187`		`- return nil, overlayutils.ErrDTypeNotSupported("overlay2", backingFs)`
	`187`	`+ if !graphdriver.IsInitialized(home) {`
	`188`	`+ return nil, overlayutils.ErrDTypeNotSupported("overlay2", backingFs)`
	`189`	`+ }`
	`190`	`+ // allow running without d_type only for existing setups (#27443)`
	`191`	`+ logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay2", backingFs))`
`188`	`192`	`}`
`189`	`193`
`190`	`194`	`rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)`