moby/pkg/archive/whiteouts.go
Daniel Nephin 4f0d95fa6e Add canonical import comment
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2018-02-05 16:51:57 -05:00

23 lines
1.1 KiB
Go

package archive // import "github.com/docker/docker/pkg/archive"
// Whiteouts are files with a special meaning for the layered filesystem.
// Docker uses AUFS whiteout files inside exported archives. In other
// filesystems these files are generated/handled on tar creation/extraction.
// WhiteoutPrefix prefix means file is a whiteout. If this is followed by a
// filename this means that file has been removed from the base layer.
const WhiteoutPrefix = ".wh."
// WhiteoutMetaPrefix prefix means whiteout has a special meaning and is not
// for removing an actual file. Normally these files are excluded from exported
// archives.
const WhiteoutMetaPrefix = WhiteoutPrefix + WhiteoutPrefix
// WhiteoutLinkDir is a directory AUFS uses for storing hardlink links to other
// layers. Normally these should not go into exported archives and all changed
// hardlinks should be copied to the top layer.
const WhiteoutLinkDir = WhiteoutMetaPrefix + "plnk"
// WhiteoutOpaqueDir file means directory has been made opaque - meaning
// readdir calls to this directory do not follow to lower layers.
const WhiteoutOpaqueDir = WhiteoutMetaPrefix + ".opq"