Merge release-20210412.0-32-g276ff149a (automated)

1 files changed, 26 insertions, 1 deletions

diff --git a/pkg/sentry/vfs/resolving_path.go b/pkg/sentry/vfs/resolving_path.go
index e4fd55012..634c8b097 100644
--- a/pkg/sentry/vfs/resolving_path.go
+++ b/pkg/sentry/vfs/resolving_path.go
@@ -120,6 +120,8 @@ var resolvingPathPool = sync.Pool{
 	},
 }
 
+// getResolvingPath gets a new ResolvingPath from the pool. Caller must call
+// ResolvingPath.Release() when done.
 func (vfs *VirtualFilesystem) getResolvingPath(creds *auth.Credentials, pop *PathOperation) *ResolvingPath {
 	rp := resolvingPathPool.Get().(*ResolvingPath)
 	rp.vfs = vfs
@@ -142,7 +144,30 @@ func (vfs *VirtualFilesystem) getResolvingPath(creds *auth.Credentials, pop *Pat
 	return rp
 }
 
-func (vfs *VirtualFilesystem) putResolvingPath(ctx context.Context, rp *ResolvingPath) {
+// Copy creates another ResolvingPath with the same state as the original.
+// Copies are independent, using the copy does not change the original and
+// vice-versa.
+//
+// Caller must call Resease() when done.
+func (rp *ResolvingPath) Copy() *ResolvingPath {
+	copy := resolvingPathPool.Get().(*ResolvingPath)
+	*copy = *rp // All fields all shallow copiable.
+
+	// Take extra reference for the copy if the original had them.
+	if copy.flags&rpflagsHaveStartRef != 0 {
+		copy.start.IncRef()
+	}
+	if copy.flags&rpflagsHaveMountRef != 0 {
+		copy.mount.IncRef()
+	}
+	// Reset error state.
+	copy.nextStart = nil
+	copy.nextMount = nil
+	return copy
+}
+
+// Release decrements references if needed and returns the object to the pool.
+func (rp *ResolvingPath) Release(ctx context.Context) {
 	rp.root = VirtualDentry{}
 	rp.decRefStartAndMount(ctx)
 	rp.mount = nil