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