Documentation
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Index ¶
- func GetOverlayLayers(m mount.Mount) ([]string, error)
- func GetUpperdir(lower, upper []mount.Mount) (string, error)
- func IsOpaqueDir(path string) (bool, error)
- func IsOverlayMountType(mnt mount.Mount) bool
- func IsRedirectDir(path string) (bool, error)
- func VolatileIncompatDir(mnt mount.Mount) string
- func VolatileIncompatDirs(mounts []mount.Mount) []string
- func WalkChanges(ctx context.Context, lowerRoot, upperRoot string, comparison Comparison, ...) error
- func WalkLayerDeltaChanges(ctx context.Context, changeFn continuityfs.ChangeFunc, delta LayerDelta, ...) error
- func WalkUpperdirChanges(ctx context.Context, changeFn continuityfs.ChangeFunc, ...) error
- func WriteUpperdir(ctx context.Context, w io.Writer, upperdir string, lower []mount.Mount) error
- type Comparison
- type LayerDelta
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func IsOpaqueDir ¶
IsOpaqueDir reports whether the overlay layer directory at path is marked opaque, hiding everything beneath it in the layers below.
func IsOverlayMountType ¶
func IsRedirectDir ¶
IsRedirectDir reports whether the overlay layer directory at path redirects to another path in the layers below, which hold its inherited contents.
func VolatileIncompatDir ¶
func VolatileIncompatDirs ¶
func WalkChanges ¶
func WalkChanges( ctx context.Context, lowerRoot, upperRoot string, comparison Comparison, changeFn continuityfs.ChangeFunc, ) error
func WalkLayerDeltaChanges ¶
func WalkLayerDeltaChanges( ctx context.Context, changeFn continuityfs.ChangeFunc, delta LayerDelta, upperView, lowerView string, comparison Comparison, ) error
WalkLayerDeltaChanges reports the changes from lowerView to upperView, the merged views of two snapshots that delta separates, in the order and with the semantics of a double walk of the two views (WalkChanges), but costing the size of delta's layers. A single upper layer above lower is WalkUpperdirChanges itself.
Every path in any of delta's layers is a candidate; each is classified by comparing the two merged views, so content a later layer reverts, or a whiteout a later layer refills, is no change. A deleted directory is reported once, without its contents, as is a directory replaced by a file. A directory opaque in any of the layers, or replaced in one (by a whiteout or a file) and made a directory again by a later one, hides the shared layers beneath it on one side, so it is diffed in full. A redirected directory is an error: the caller falls back to WalkChanges.
func WalkUpperdirChanges ¶
func WalkUpperdirChanges( ctx context.Context, changeFn continuityfs.ChangeFunc, upperdir, upperdirView, base string, comparison Comparison, ) error
Types ¶
type Comparison ¶
type Comparison uint8
const ( CompareCompat Comparison = iota CompareContentOnMetadataMatch // CompareInodeThenContent treats files backed by the same inode as // unchanged and compares content whenever distinct files have otherwise // matching metadata. Snapshots of a shared lineage resolve unchanged // files to the same backing inode even across separate mounts, so this // stays O(changed files) there while still catching files whose stat // happens to collide (same size and mtime, different bytes). CompareInodeThenContent // CompareInodeOnly is a conservative, content-free variant for bounded // inspections. Distinct backing files always count as potentially changed, // even if all their metadata matches. CompareInodeOnly )
type LayerDelta ¶
type LayerDelta struct {
// Lower are the layers only the lower snapshot has.
Lower []string
// Upper are the layers only the upper snapshot has.
Upper []string
// Same reports that both snapshots have exactly the same layers: their
// trees are identical.
Same bool
}
LayerDelta is what separates two overlay snapshots of one lineage: the layers each has above the layers they share, bottom first. Every difference between the two trees is recorded in those layers: on top of the same shared layers, a path can only differ where one side's own layers hold an entry for it.
func GetLayerDelta ¶
func GetLayerDelta(lower, upper []mount.Mount) (LayerDelta, error)
GetLayerDelta returns the layers separating lower from upper, two snapshots that share their bottom layers: upper one or more operations above lower (GetUpperdir's case, generalized to several layers), or both built on a common ancestor, as two copy-on-write children of one snapshot are. It fails when they share no layer, or nothing separates them.
func (*LayerDelta) Empty ¶
func (d *LayerDelta) Empty() bool
Empty reports whether there is nothing to go by: no layers to walk, nor the knowledge that there are none because both sides are the same.
Source Files