gofer

const (
	// InteropModeExclusive is appropriate when the filesystem client is the
	// only user of the remote filesystem.
	//
	// - The client may cache arbitrary filesystem state (file data, metadata,
	// filesystem structure, etc.).
	//
	// - Client changes to filesystem state may be sent to the remote
	// filesystem asynchronously, except when server permission checks are
	// necessary.
	//
	// - File timestamps are based on client clocks. This ensures that users of
	// the client observe timestamps that are coherent with their own clocks
	// and consistent with Linux's semantics (in particular, it is not always
	// possible for clients to set arbitrary atimes and mtimes depending on the
	// remote filesystem implementation, and never possible for clients to set
	// arbitrary ctimes.)
	InteropModeExclusive InteropMode = iota

	// InteropModeWritethrough is appropriate when there are read-only users of
	// the remote filesystem that expect to observe changes made by the
	// filesystem client.
	//
	// - The client may cache arbitrary filesystem state.
	//
	// - Client changes to filesystem state must be sent to the remote
	// filesystem synchronously.
	//
	// - File timestamps are based on client clocks. As a corollary, access
	// timestamp changes from other remote filesystem users will not be visible
	// to the client.
	InteropModeWritethrough

	// InteropModeShared is appropriate when there are users of the remote
	// filesystem that may mutate its state other than the client.
	//
	// - The client must verify ("revalidate") cached filesystem state before
	// using it.
	//
	// - Client changes to filesystem state must be sent to the remote
	// filesystem synchronously.
	//
	// - File timestamps are based on server clocks. This is necessary to
	// ensure that timestamp changes are synchronized between remote filesystem
	// users.
	//
	// Note that the correctness of InteropModeShared depends on the server
	// correctly implementing 9P fids (i.e. each fid immutably represents a
	// single filesystem object), even in the presence of remote filesystem
	// mutations from other users. If this is violated, the behavior of the
	// client is undefined.
	InteropModeShared
)