DockerCLI/vendor/github.com/Microsoft/hcsshim/internal/wclayer/preparelayer.go

41 lines
1.2 KiB
Go

package wclayer
import (
"sync"
"github.com/Microsoft/hcsshim/internal/hcserror"
"github.com/sirupsen/logrus"
)
var prepareLayerLock sync.Mutex
// PrepareLayer finds a mounted read-write layer matching path and enables the
// the filesystem filter for use on that layer. This requires the paths to all
// parent layers, and is necessary in order to view or interact with the layer
// as an actual filesystem (reading and writing files, creating directories, etc).
// Disabling the filter must be done via UnprepareLayer.
func PrepareLayer(path string, parentLayerPaths []string) error {
title := "hcsshim::PrepareLayer "
logrus.Debugf(title+"path %s", path)
// Generate layer descriptors
layers, err := layerPathsToDescriptors(parentLayerPaths)
if err != nil {
return err
}
// This lock is a temporary workaround for a Windows bug. Only allowing one
// call to prepareLayer at a time vastly reduces the chance of a timeout.
prepareLayerLock.Lock()
defer prepareLayerLock.Unlock()
err = prepareLayer(&stdDriverInfo, path, layers)
if err != nil {
err = hcserror.Errorf(err, title, "path=%s", path)
logrus.Error(err)
return err
}
logrus.Debugf(title+"succeeded path=%s", path)
return nil
}