state_owner {
	struct nfs_server    *so_server;
	struct list_head     so_lru;
	unsigned long        so_expires;
	struct rb_node	     so_server_node;

	struct rpc_cred	     *so_cred;	 /* Associated cred */

	spinlock_t	     so_lock;
	atomic_t	     so_count;
	unsigned long	     so_flags;
	struct list_head     so_states;
	struct nfs_seqid_counter so_seqid;
	seqcount_t	     so_reclaim_seqcount;
	struct mutex	     so_delegreturn_mutex;
};

enum {
	NFS_OWNER_RECLAIM_REBOOT,
	NFS_OWNER_RECLAIM_NOGRACE
};

#define NFS_LOCK_NEW		0
#define NFS_LOCK_RECLAIM	1
#define NFS_LOCK_EXPIRED	2

/*
 * struct nfs4_state maintains the client-side state for a given
 * (state_owner,inode) tuple (OPEN) or state_owner (LOCK).
 *
 * OPEN:
 * In order to know when to OPEN_DOWNGRADE or CLOSE the state on the server,
 * we need to know how many files are open for reading or writing on a
 * given inode. This information too is stored here.
 *
 * LOCK: one nfs4_state (LOCK) to hold the lock stateid nfs4_state(OPEN)
 */

struct nfs4_lock_owner {
	unsigned int lo_type;
#define NFS4_ANY_LOCK_TYPE	(0U)
#define NFS4_FLOCK_LOCK_TYPE	(1U << 0)
#define NFS4_POSIX_LOCK_TYPE	(1U << 1)
	union {
		fl_owner_t posix_owner;
		pid_t flock_owner;
	} lo_u;
};

struct nfs4_lock_state {
	struct list_head	ls_locks;	/* Other lock stateids */
	struct nfs4_state *	ls_state;	/* Pointer to open state */
#define NFS_LOCK_INITIALIZED 0
	unsigned long		ls_flags;
	struct nfs_seqid_counter	ls_seqid;
	nfs4_stateid		ls_stateid;
	atomic_t		ls_count;
	struct nfs4_lock_owner	ls_owner;
};

/* bits for nfs4_state->flags */
enum {
	LK_STATE_IN_USE,
	NFS_DELEGATED_STATE,		/* Current stateid is delegation */
	NFS_OPEN_STATE,			/* OPEN stateid is set */
	NFS_O_RDONLY_STATE,		/* OPEN stateid has read-only state */
	NFS_O_WRONLY_STATE,		/* OPEN stateid has write-only state */
	NFS_O_RDWR_STATE,		/* OPEN stateid has read/write state */
	NFS_STATE_RECLAIM_REBOOT,	/* OPEN stateid server rebooted */
	NFS_STATE_RECLAIM_NOGRACE,	/* OPEN stateid needs to recover state */
	NFS_STATE_POSIX_LOCKS,