overlay

Documentation

Overview

Package overlay provides an overlay filesystem implementation, which synthesizes a filesystem by composing one or more immutable filesystems ("lower layers") with an optional mutable filesystem ("upper layer").

Lock order:

directoryFD.mu / regularFileFD.mu

filesystem.renameMu
  dentry.dirMu
    dentry.copyMu
      filesystem.devMu
      *** "memmap.Mappable locks" below this point
      dentry.mapsMu
        *** "memmap.Mappable locks taken by Translate" below this point
        dentry.dataMu

Locking dentry.dirMu in multiple dentries requires that parent dentries are locked before child dentries, and that filesystem.renameMu is locked to stabilize this relationship.

Index

• Constants
• type FilesystemOptions
  • func (f *FilesystemOptions) StateFields() []string
  • func (f *FilesystemOptions) StateLoad(stateSourceObject state.Source)
  • func (f *FilesystemOptions) StateSave(stateSinkObject state.Sink)
  • func (f *FilesystemOptions) StateTypeName() string
• type FilesystemType
  • func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, ...) (*vfs.Filesystem, *vfs.Dentry, error)
  • func (FilesystemType) Name() string
  • func (FilesystemType) Release(ctx context.Context)
  • func (fstype *FilesystemType) StateFields() []string
  • func (fstype *FilesystemType) StateLoad(stateSourceObject state.Source)
  • func (fstype *FilesystemType) StateSave(stateSinkObject state.Sink)
  • func (fstype *FilesystemType) StateTypeName() string

Constants

const Name = "overlay"

Name is the default filesystem name.

Types

type FilesystemOptions

type FilesystemOptions struct {

	// If UpperRoot.Ok(), it is the root of the writable upper layer of the
	// overlay.
	UpperRoot vfs.VirtualDentry

	// LowerRoots contains the roots of the immutable lower layers of the
	// overlay. LowerRoots is immutable.
	LowerRoots []vfs.VirtualDentry
}

FilesystemOptions may be passed as vfs.GetFilesystemOptions.InternalData to FilesystemType.GetFilesystem.

+stateify savable

func (*FilesystemOptions) StateFields

func (f *FilesystemOptions) StateFields() []string

func (*FilesystemOptions) StateLoad

func (f *FilesystemOptions) StateLoad(stateSourceObject state.Source)

+checklocksignore

func (*FilesystemOptions) StateSave

func (f *FilesystemOptions) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*FilesystemOptions) StateTypeName

func (f *FilesystemOptions) StateTypeName() string

type FilesystemType

type FilesystemType struct{}

FilesystemType implements vfs.FilesystemType.

+stateify savable

func (FilesystemType) GetFilesystem

func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error)

GetFilesystem implements vfs.FilesystemType.GetFilesystem.

func (FilesystemType) Name

func (FilesystemType) Name() string

Name implements vfs.FilesystemType.Name.

func (FilesystemType) Release

func (FilesystemType) Release(ctx context.Context)

Release implements FilesystemType.Release.

func (*FilesystemType) StateFields

func (fstype *FilesystemType) StateFields() []string

func (*FilesystemType) StateLoad

func (fstype *FilesystemType) StateLoad(stateSourceObject state.Source)

+checklocksignore

func (*FilesystemType) StateSave

func (fstype *FilesystemType) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*FilesystemType) StateTypeName

func (fstype *FilesystemType) StateTypeName() string