/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * linux/fs/nfs/nfs4_fs.h
   *
   * Copyright (C) 2005 Trond Myklebust
   *
   * NFSv4-specific filesystem definitions and declarations
   */
  
  #ifndef __LINUX_FS_NFS_NFS4_FS_H
  #define __LINUX_FS_NFS_NFS4_FS_H

  #if defined(CONFIG_NFS_V4_2)
  #define NFS4_MAX_MINOR_VERSION 2
  #elif defined(CONFIG_NFS_V4_1)
  #define NFS4_MAX_MINOR_VERSION 1
  #else
  #define NFS4_MAX_MINOR_VERSION 0
  #endif

  #if IS_ENABLED(CONFIG_NFS_V4)

  #define NFS4_MAX_LOOP_ON_RECOVER (10)

  #include <linux/seqlock.h>

  struct idmap;

  enum nfs4_client_state {

  	NFS4CLNT_MANAGER_RUNNING  = 0,

  	NFS4CLNT_CHECK_LEASE,

  	NFS4CLNT_LEASE_EXPIRED,

  	NFS4CLNT_RECLAIM_REBOOT,
  	NFS4CLNT_RECLAIM_NOGRACE,

  	NFS4CLNT_DELEGRETURN,

  	NFS4CLNT_SESSION_RESET,

  	NFS4CLNT_LEASE_CONFIRM,

  	NFS4CLNT_SERVER_SCOPE_MISMATCH,

  	NFS4CLNT_PURGE_STATE,

  	NFS4CLNT_BIND_CONN_TO_SESSION,

  	NFS4CLNT_MOVED,

  	NFS4CLNT_LEASE_MOVED,

  	NFS4CLNT_DELEGATION_EXPIRED,

  	NFS4CLNT_RUN_MANAGER,

  	NFS4CLNT_RECALL_RUNNING,
  	NFS4CLNT_RECALL_ANY_LAYOUT_READ,
  	NFS4CLNT_RECALL_ANY_LAYOUT_RW,

  };

  #define NFS4_RENEW_TIMEOUT		0x01
  #define NFS4_RENEW_DELEGATION_CB	0x02

  struct nfs_seqid_counter;

  struct nfs4_minor_version_ops {
  	u32	minor_version;

  	unsigned init_caps;

  	int	(*init_client)(struct nfs_client *);
  	void	(*shutdown_client)(struct nfs_client *);

  	bool	(*match_stateid)(const nfs4_stateid *,

  			const nfs4_stateid *);

  	int	(*find_root_sec)(struct nfs_server *, struct nfs_fh *,
  			struct nfs_fsinfo *);

  	void	(*free_lock_state)(struct nfs_server *,

  			struct nfs4_lock_state *);

  	int	(*test_and_free_expired)(struct nfs_server *,

  			nfs4_stateid *, const struct cred *);

  	struct nfs_seqid *
  		(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);

  	void	(*session_trunk)(struct rpc_clnt *clnt,
  			struct rpc_xprt *xprt, void *data);

  	const struct rpc_call_ops *call_sync_ops;

  	const struct nfs4_state_recovery_ops *reboot_recovery_ops;
  	const struct nfs4_state_recovery_ops *nograce_recovery_ops;
  	const struct nfs4_state_maintenance_ops *state_renewal_ops;

  	const struct nfs4_mig_recovery_ops *mig_recovery_ops;

  };

  #define NFS_SEQID_CONFIRMED 1
  struct nfs_seqid_counter {

  	ktime_t create_time;

  	int owner_id;

  	int flags;
  	u32 counter;

  	spinlock_t lock;		/* Protects the list */
  	struct list_head list;		/* Defines sequence of RPC calls */
  	struct rpc_wait_queue	wait;	/* RPC call delay queue */

  };
  
  struct nfs_seqid {

  	struct nfs_seqid_counter *sequence;

  	struct list_head list;

  	struct rpc_task *task;

  };
  
  static inline void nfs_confirm_seqid(struct nfs_seqid_counter *seqid, int status)
  {
  	if (seqid_mutating_err(-status))
  		seqid->flags |= NFS_SEQID_CONFIRMED;
  }
  
  /*

   * NFS4 state_owners and lock_owners are simply labels for ordered
   * sequences of RPC calls. Their sole purpose is to provide once-only
   * semantics by allowing the server to identify replayed requests.

   */
  struct nfs4_state_owner {

  	struct nfs_server    *so_server;

  	struct list_head     so_lru;
  	unsigned long        so_expires;

  	struct rb_node	     so_server_node;

  	const struct 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_spinlock_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_state {

  	struct list_head	ls_locks;	/* Other lock stateids */
  	struct nfs4_state *	ls_state;	/* Pointer to open state */

  #define NFS_LOCK_INITIALIZED 0

  #define NFS_LOCK_LOST        1

  	unsigned long		ls_flags;

  	struct nfs_seqid_counter	ls_seqid;

  	nfs4_stateid		ls_stateid;

  	refcount_t		ls_count;

  	fl_owner_t		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,		/* Posix locks are supported */

  	NFS_STATE_RECOVERY_FAILED,	/* OPEN stateid state recovery failed */

  	NFS_STATE_MAY_NOTIFY_LOCK,	/* server may CB_NOTIFY_LOCK */

  	NFS_STATE_CHANGE_WAIT,		/* A state changing operation is outstanding */

  	NFS_CLNT_DST_SSC_COPY_STATE,    /* dst server open state on client*/

  	NFS_CLNT_SRC_SSC_COPY_STATE,    /* src server open state on client*/

  	NFS_SRV_SSC_COPY_STATE,		/* ssc state on the dst server */

  };
  
  struct nfs4_state {
  	struct list_head open_states;	/* List of states for the same state_owner */
  	struct list_head inode_states;	/* List of states for the same inode */
  	struct list_head lock_states;	/* List of subservient lock stateids */
  
  	struct nfs4_state_owner *owner;	/* Pointer to the open owner */
  	struct inode *inode;		/* Pointer to the inode */
  
  	unsigned long flags;		/* Do we hold any locks? */

  	spinlock_t state_lock;		/* Protects the lock_states list */

  	seqlock_t seqlock;		/* Protects the stateid/open_stateid */

  	nfs4_stateid stateid;		/* Current stateid: may be delegation */
  	nfs4_stateid open_stateid;	/* OPEN stateid */

  	/* The following 3 fields are protected by owner->so_lock */

  	unsigned int n_rdonly;		/* Number of read-only references */
  	unsigned int n_wronly;		/* Number of write-only references */
  	unsigned int n_rdwr;		/* Number of read/write references */

  	fmode_t state;			/* State on the server (R,W, or RW) */

  	refcount_t count;

  
  	wait_queue_head_t waitq;

  	struct rcu_head rcu_head;

  };
  
  
  struct nfs4_exception {

  	struct nfs4_state *state;

  	struct inode *inode;

  	nfs4_stateid *stateid;

  	long timeout;
  	unsigned char delay : 1,
  		      recovering : 1,
  		      retry : 1;

  	bool interruptible;

  };
  
  struct nfs4_state_recovery_ops {

  	int owner_flag_bit;

  	int state_flag_bit;

  	int (*recover_open)(struct nfs4_state_owner *, struct nfs4_state *);
  	int (*recover_lock)(struct nfs4_state *, struct file_lock *);

  	int (*establish_clid)(struct nfs_client *, const struct cred *);
  	int (*reclaim_complete)(struct nfs_client *, const struct cred *);

  	int (*detect_trunking)(struct nfs_client *, struct nfs_client **,

  		const struct cred *);

  };

  struct nfs4_opendata {
  	struct kref kref;
  	struct nfs_openargs o_arg;
  	struct nfs_openres o_res;
  	struct nfs_open_confirmargs c_arg;
  	struct nfs_open_confirmres c_res;
  	struct nfs4_string owner_name;
  	struct nfs4_string group_name;
  	struct nfs4_label *a_label;
  	struct nfs_fattr f_attr;
  	struct nfs4_label *f_label;
  	struct dentry *dir;
  	struct dentry *dentry;
  	struct nfs4_state_owner *owner;
  	struct nfs4_state *state;
  	struct iattr attrs;
  	struct nfs4_layoutget *lgp;
  	unsigned long timestamp;
  	bool rpc_done;
  	bool file_created;
  	bool is_recover;
  	bool cancelled;
  	int rpc_status;
  };

  struct nfs4_add_xprt_data {
  	struct nfs_client	*clp;

  	const struct cred	*cred;

  };

  struct nfs4_state_maintenance_ops {

  	int (*sched_state_renewal)(struct nfs_client *, const struct cred *, unsigned);
  	const struct cred * (*get_state_renewal_cred)(struct nfs_client *);
  	int (*renew_lease)(struct nfs_client *, const struct cred *);

  };

  struct nfs4_mig_recovery_ops {

  	int (*get_locations)(struct inode *, struct nfs4_fs_locations *,

  		struct page *, const struct cred *);
  	int (*fsid_present)(struct inode *, const struct cred *);

  };

  extern const struct dentry_operations nfs4_dentry_operations;

  
  /* dir.c */
  int nfs_atomic_open(struct inode *, struct dentry *, struct file *,

  		    unsigned, umode_t);

  /* fs_context.c */

  extern struct file_system_type nfs4_fs_type;

  /* nfs4namespace.c */

  struct rpc_clnt *nfs4_negotiate_security(struct rpc_clnt *, struct inode *,
  					 const struct qstr *);

  int nfs4_submount(struct fs_context *, struct nfs_server *);

  int nfs4_replace_transport(struct nfs_server *server,
  				const struct nfs4_fs_locations *locations);

  /* nfs4proc.c */

  extern int nfs4_handle_exception(struct nfs_server *, int, struct nfs4_exception *);

  extern int nfs4_async_handle_error(struct rpc_task *task,
  				   struct nfs_server *server,
  				   struct nfs4_state *state, long *timeout);

  extern int nfs4_call_sync(struct rpc_clnt *, struct nfs_server *,
  			  struct rpc_message *, struct nfs4_sequence_args *,
  			  struct nfs4_sequence_res *, int);

  extern void nfs4_init_sequence(struct nfs4_sequence_args *, struct nfs4_sequence_res *, int, int);

  extern int nfs4_proc_setclientid(struct nfs_client *, u32, unsigned short, const struct cred *, struct nfs4_setclientid_res *);
  extern int nfs4_proc_setclientid_confirm(struct nfs_client *, struct nfs4_setclientid_res *arg, const struct cred *);

  extern int nfs4_proc_get_rootfh(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *, bool);

  extern int nfs4_proc_bind_conn_to_session(struct nfs_client *, const struct cred *cred);
  extern int nfs4_proc_exchange_id(struct nfs_client *clp, const struct cred *cred);

  extern int nfs4_destroy_clientid(struct nfs_client *clp);

  extern int nfs4_init_clientid(struct nfs_client *, const struct cred *);
  extern int nfs41_init_clientid(struct nfs_client *, const struct cred *);

  extern int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait);

  extern int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle);

  extern int nfs4_proc_fs_locations(struct rpc_clnt *, struct inode *, const struct qstr *,
  				  struct nfs4_fs_locations *, struct page *);

  extern int nfs4_proc_get_locations(struct inode *, struct nfs4_fs_locations *,

  		struct page *page, const struct cred *);
  extern int nfs4_proc_fsid_present(struct inode *, const struct cred *);

  extern struct rpc_clnt *nfs4_proc_lookup_mountpoint(struct inode *,
  						    struct dentry *,
  						    struct nfs_fh *,
  						    struct nfs_fattr *);

  extern int nfs4_proc_secinfo(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);

  extern const struct xattr_handler *nfs4_xattr_handlers[];

  extern int nfs4_set_rw_stateid(nfs4_stateid *stateid,

  		const struct nfs_open_context *ctx,
  		const struct nfs_lock_context *l_ctx,
  		fmode_t fmode);

  extern int nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
  			     struct nfs_fattr *fattr, struct nfs4_label *label,
  			     struct inode *inode);
  extern int update_open_stateid(struct nfs4_state *state,
  				const nfs4_stateid *open_stateid,
  				const nfs4_stateid *deleg_stateid,
  				fmode_t fmode);

  extern int nfs4_proc_get_lease_time(struct nfs_client *clp,
  		struct nfs_fsinfo *fsinfo);

  extern void nfs4_update_changeattr(struct inode *dir,
  				   struct nfs4_change_info *cinfo,
  				   unsigned long timestamp,
  				   unsigned long cache_validity);

  extern int nfs4_buf_to_pages_noslab(const void *buf, size_t buflen,
  				    struct page **pages);

  #if defined(CONFIG_NFS_V4_1)

  extern int nfs41_sequence_done(struct rpc_task *, struct nfs4_sequence_res *);

  extern int nfs4_proc_create_session(struct nfs_client *, const struct cred *);
  extern int nfs4_proc_destroy_session(struct nfs4_session *, const struct cred *);

  extern int nfs4_proc_layoutcommit(struct nfs4_layoutcommit_data *data,

  				  bool sync);

  extern int nfs4_detect_session_trunking(struct nfs_client *clp,
  		struct nfs41_exchange_id_res *res, struct rpc_xprt *xprt);

  
  static inline bool
  is_ds_only_client(struct nfs_client *clp)
  {
  	return (clp->cl_exchange_flags & EXCHGID4_FLAG_MASK_PNFS) ==
  		EXCHGID4_FLAG_USE_PNFS_DS;
  }

  
  static inline bool
  is_ds_client(struct nfs_client *clp)
  {
  	return clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_DS;
  }

  static inline bool
  _nfs4_state_protect(struct nfs_client *clp, unsigned long sp4_mode,
  		    struct rpc_clnt **clntp, struct rpc_message *msg)

  {

  	rpc_authflavor_t flavor;

  	if (sp4_mode == NFS_SP4_MACH_CRED_CLEANUP ||
  	    sp4_mode == NFS_SP4_MACH_CRED_PNFS_CLEANUP) {
  		/* Using machine creds for cleanup operations
  		 * is only relevent if the client credentials
  		 * might expire. So don't bother for
  		 * RPC_AUTH_UNIX.  If file was only exported to
  		 * sec=sys, the PUTFH would fail anyway.
  		 */
  		if ((*clntp)->cl_auth->au_flavor == RPC_AUTH_UNIX)
  			return false;
  	}

  	if (test_bit(sp4_mode, &clp->cl_sp4_flags)) {

  		msg->rpc_cred = rpc_machine_cred();

  
  		flavor = clp->cl_rpcclient->cl_auth->au_flavor;

  		WARN_ON_ONCE(flavor != RPC_AUTH_GSS_KRB5I &&
  			     flavor != RPC_AUTH_GSS_KRB5P);

  		*clntp = clp->cl_rpcclient;

  
  		return true;

  	}

  	return false;
  }
  
  /*
   * Function responsible for determining if an rpc_message should use the
   * machine cred under SP4_MACH_CRED and if so switching the credential and
   * authflavor (using the nfs_client's rpc_clnt which will be krb5i/p).
   * Should be called before rpc_call_sync/rpc_call_async.
   */
  static inline void
  nfs4_state_protect(struct nfs_client *clp, unsigned long sp4_mode,
  		   struct rpc_clnt **clntp, struct rpc_message *msg)
  {
  	_nfs4_state_protect(clp, sp4_mode, clntp, msg);
  }
  
  /*
   * Special wrapper to nfs4_state_protect for write.
   * If WRITE can use machine cred but COMMIT cannot, make sure all writes
   * that use machine cred use NFS_FILE_SYNC.
   */
  static inline void
  nfs4_state_protect_write(struct nfs_client *clp, struct rpc_clnt **clntp,

  			 struct rpc_message *msg, struct nfs_pgio_header *hdr)

  {
  	if (_nfs4_state_protect(clp, NFS_SP4_MACH_CRED_WRITE, clntp, msg) &&
  	    !test_bit(NFS_SP4_MACH_CRED_COMMIT, &clp->cl_sp4_flags))

  		hdr->args.stable = NFS_FILE_SYNC;

  }

  #else /* CONFIG_NFS_v4_1 */

  static inline bool
  is_ds_only_client(struct nfs_client *clp)

  {
  	return false;
  }
  
  static inline bool
  is_ds_client(struct nfs_client *clp)

  {
  	return false;
  }

  
  static inline void
  nfs4_state_protect(struct nfs_client *clp, unsigned long sp4_flags,
  		   struct rpc_clnt **clntp, struct rpc_message *msg)
  {
  }

  
  static inline void
  nfs4_state_protect_write(struct nfs_client *clp, struct rpc_clnt **clntp,

  			 struct rpc_message *msg, struct nfs_pgio_header *hdr)

  {
  }

  #endif /* CONFIG_NFS_V4_1 */

  extern const struct nfs4_minor_version_ops *nfs_v4_minor_ops[];

  extern const u32 nfs4_fattr_bitmap[3];

  extern const u32 nfs4_statfs_bitmap[3];
  extern const u32 nfs4_pathconf_bitmap[3];

  extern const u32 nfs4_fsinfo_bitmap[3];

  extern const u32 nfs4_fs_locations_bitmap[3];

  void nfs40_shutdown_client(struct nfs_client *);
  void nfs41_shutdown_client(struct nfs_client *);
  int nfs40_init_client(struct nfs_client *);
  int nfs41_init_client(struct nfs_client *);

  void nfs4_free_client(struct nfs_client *);

  struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *);

  /* nfs4renewd.c */

  extern void nfs4_schedule_state_renewal(struct nfs_client *);

  extern void nfs4_renewd_prepare_shutdown(struct nfs_server *);

  extern void nfs4_kill_renewd(struct nfs_client *);

  extern void nfs4_renew_state(struct work_struct *);

  extern void nfs4_set_lease_period(struct nfs_client *clp, unsigned long lease);

  
  /* nfs4state.c */

  extern const nfs4_stateid current_stateid;

  const struct cred *nfs4_get_clid_cred(struct nfs_client *clp);
  const struct cred *nfs4_get_machine_cred(struct nfs_client *clp);
  const struct cred *nfs4_get_renew_cred(struct nfs_client *clp);

  int nfs4_discover_server_trunking(struct nfs_client *clp,
  			struct nfs_client **);
  int nfs40_discover_server_trunking(struct nfs_client *clp,

  			struct nfs_client **, const struct cred *);

  #if defined(CONFIG_NFS_V4_1)

  int nfs41_discover_server_trunking(struct nfs_client *clp,

  			struct nfs_client **, const struct cred *);

  extern void nfs4_schedule_session_recovery(struct nfs4_session *, int);

  extern void nfs41_notify_server(struct nfs_client *);

  bool nfs4_check_serverowner_major_id(struct nfs41_server_owner *o1,
  			struct nfs41_server_owner *o2);

  #else

  static inline void nfs4_schedule_session_recovery(struct nfs4_session *session, int err)

  {
  }

  #endif /* CONFIG_NFS_V4_1 */

  extern struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *, const struct cred *, gfp_t);

  extern void nfs4_put_state_owner(struct nfs4_state_owner *);

  extern void nfs4_purge_state_owners(struct nfs_server *, struct list_head *);
  extern void nfs4_free_state_owners(struct list_head *head);

  extern struct nfs4_state * nfs4_get_open_state(struct inode *, struct nfs4_state_owner *);
  extern void nfs4_put_open_state(struct nfs4_state *);

  extern void nfs4_close_state(struct nfs4_state *, fmode_t);
  extern void nfs4_close_sync(struct nfs4_state *, fmode_t);

  extern void nfs4_state_set_mode_locked(struct nfs4_state *, fmode_t);

  extern void nfs_inode_find_state_and_recover(struct inode *inode,
  		const nfs4_stateid *stateid);

  extern int nfs4_state_mark_reclaim_nograce(struct nfs_client *, struct nfs4_state *);

  extern void nfs4_schedule_lease_recovery(struct nfs_client *);

  extern int nfs4_wait_clnt_recover(struct nfs_client *clp);
  extern int nfs4_client_recover_expired_lease(struct nfs_client *clp);

  extern void nfs4_schedule_state_manager(struct nfs_client *);

  extern void nfs4_schedule_path_down_recovery(struct nfs_client *clp);

  extern int nfs4_schedule_stateid_recovery(const struct nfs_server *, struct nfs4_state *);

  extern int nfs4_schedule_migration_recovery(const struct nfs_server *);

  extern void nfs4_schedule_lease_moved_recovery(struct nfs_client *);

  extern void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags, bool);

  extern void nfs41_handle_server_scope(struct nfs_client *,

  				      struct nfs41_server_scope **);

  extern void nfs4_put_lock_state(struct nfs4_lock_state *lsp);

  extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);

  extern int nfs4_select_rw_stateid(struct nfs4_state *, fmode_t,

  		const struct nfs_lock_context *, nfs4_stateid *,

  		const struct cred **);

  extern bool nfs4_copy_open_stateid(nfs4_stateid *dst,
  		struct nfs4_state *state);

  extern struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter, gfp_t gfp_mask);

  extern int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task);
  extern void nfs_increment_open_seqid(int status, struct nfs_seqid *seqid);
  extern void nfs_increment_lock_seqid(int status, struct nfs_seqid *seqid);

  extern void nfs_release_seqid(struct nfs_seqid *seqid);

  extern void nfs_free_seqid(struct nfs_seqid *seqid);

  extern int nfs4_setup_sequence(struct nfs_client *client,

  				struct nfs4_sequence_args *args,
  				struct nfs4_sequence_res *res,
  				struct rpc_task *task);

  extern int nfs4_sequence_done(struct rpc_task *task,
  			      struct nfs4_sequence_res *res);

  extern void nfs4_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp);

  extern int nfs4_proc_commit(struct file *dst, __u64 offset, __u32 count, struct nfs_commitres *res);

  extern const nfs4_stateid zero_stateid;

  extern const nfs4_stateid invalid_stateid;

  /* nfs4super.c */

  struct nfs_mount_info;

  extern struct nfs_subversion nfs_v4;

  extern bool nfs4_disable_idmapping;
  extern unsigned short max_session_slots;

  extern unsigned short max_session_cb_slots;

  extern unsigned short send_implementation_id;

  extern bool recover_lost_locks;

  #define NFS4_CLIENT_ID_UNIQ_LEN		(64)
  extern char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN];

  extern int nfs4_try_get_tree(struct fs_context *);
  extern int nfs4_get_referral_tree(struct fs_context *);

  /* nfs4sysctl.c */
  #ifdef CONFIG_SYSCTL
  int nfs4_register_sysctl(void);
  void nfs4_unregister_sysctl(void);
  #else
  static inline int nfs4_register_sysctl(void)
  {
  	return 0;
  }

  static inline void nfs4_unregister_sysctl(void)

  {
  }
  #endif

  /* nfs4xdr.c */

  extern const struct rpc_procinfo nfs4_procedures[];

  #ifdef CONFIG_NFS_V4_2
  extern const u32 nfs42_maxsetxattr_overhead;
  extern const u32 nfs42_maxgetxattr_overhead;
  extern const u32 nfs42_maxlistxattrs_overhead;
  #endif

  struct nfs4_mount_data;
  
  /* callback_xdr.c */

  extern const struct svc_version nfs4_callback_version1;
  extern const struct svc_version nfs4_callback_version4;

  static inline void nfs4_stateid_copy(nfs4_stateid *dst, const nfs4_stateid *src)
  {

  	memcpy(dst->data, src->data, sizeof(dst->data));
  	dst->type = src->type;

  }
  
  static inline bool nfs4_stateid_match(const nfs4_stateid *dst, const nfs4_stateid *src)
  {

  	if (dst->type != src->type)
  		return false;
  	return memcmp(dst->data, src->data, sizeof(dst->data)) == 0;

  }

  static inline bool nfs4_stateid_match_other(const nfs4_stateid *dst, const nfs4_stateid *src)
  {
  	return memcmp(dst->other, src->other, NFS4_STATEID_OTHER_SIZE) == 0;
  }
  
  static inline bool nfs4_stateid_is_newer(const nfs4_stateid *s1, const nfs4_stateid *s2)
  {
  	return (s32)(be32_to_cpu(s1->seqid) - be32_to_cpu(s2->seqid)) > 0;
  }

  static inline bool nfs4_stateid_is_next(const nfs4_stateid *s1, const nfs4_stateid *s2)
  {
  	u32 seq1 = be32_to_cpu(s1->seqid);
  	u32 seq2 = be32_to_cpu(s2->seqid);
  
  	return seq2 == seq1 + 1U || (seq2 == 1U && seq1 == 0xffffffffU);
  }

  static inline bool nfs4_stateid_match_or_older(const nfs4_stateid *dst, const nfs4_stateid *src)
  {
  	return nfs4_stateid_match_other(dst, src) &&
  		!(src->seqid && nfs4_stateid_is_newer(dst, src));
  }

  static inline void nfs4_stateid_seqid_inc(nfs4_stateid *s1)
  {
  	u32 seqid = be32_to_cpu(s1->seqid);
  
  	if (++seqid == 0)
  		++seqid;
  	s1->seqid = cpu_to_be32(seqid);
  }

  static inline bool nfs4_valid_open_stateid(const struct nfs4_state *state)
  {
  	return test_bit(NFS_STATE_RECOVERY_FAILED, &state->flags) == 0;
  }

  static inline bool nfs4_state_match_open_stateid_other(const struct nfs4_state *state,
  		const nfs4_stateid *stateid)
  {
  	return test_bit(NFS_OPEN_STATE, &state->flags) &&
  		nfs4_stateid_match_other(&state->open_stateid, stateid);
  }

  /* nfs42xattr.c */
  #ifdef CONFIG_NFS_V4_2
  extern int __init nfs4_xattr_cache_init(void);
  extern void nfs4_xattr_cache_exit(void);
  extern void nfs4_xattr_cache_add(struct inode *inode, const char *name,
  				 const char *buf, struct page **pages,
  				 ssize_t buflen);
  extern void nfs4_xattr_cache_remove(struct inode *inode, const char *name);
  extern ssize_t nfs4_xattr_cache_get(struct inode *inode, const char *name,
  				char *buf, ssize_t buflen);
  extern void nfs4_xattr_cache_set_list(struct inode *inode, const char *buf,
  				      ssize_t buflen);
  extern ssize_t nfs4_xattr_cache_list(struct inode *inode, char *buf,
  				     ssize_t buflen);
  extern void nfs4_xattr_cache_zap(struct inode *inode);

  #else

  static inline void nfs4_xattr_cache_zap(struct inode *inode)
  {
  }
  #endif /* CONFIG_NFS_V4_2 */
  
  #else /* CONFIG_NFS_V4 */

  #define nfs4_close_state(a, b) do { } while (0)
  #define nfs4_close_sync(a, b) do { } while (0)

  #define nfs4_state_protect(a, b, c, d) do { } while (0)
  #define nfs4_state_protect_write(a, b, c, d) do { } while (0)

  #endif /* CONFIG_NFS_V4 */
  #endif /* __LINUX_FS_NFS_NFS4_FS.H */