text: /*
   * 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 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,
  };
  
  #define NFS4_RENEW_TIMEOUT		0x01
  #define NFS4_RENEW_DELEGATION_CB	0x02
  
  struct nfs4_minor_version_ops {
  	u32	minor_version;
  	unsigned init_caps;
  
  	int	(*call_sync)(struct rpc_clnt *clnt,
  			struct nfs_server *server,
  			struct rpc_message *msg,
  			struct nfs4_sequence_args *args,
  			struct nfs4_sequence_res *res);
  	bool	(*match_stateid)(const nfs4_stateid *,
  			const nfs4_stateid *);
  	int	(*find_root_sec)(struct nfs_server *, struct nfs_fh *,
  			struct nfs_fsinfo *);
  	int	(*free_lock_state)(struct nfs_server *,
  			struct nfs4_lock_state *);
  	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;
  };
  
  #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;
  
  	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,		/* Posix locks are supported */
  	NFS_STATE_RECOVERY_FAILED,	/* OPEN stateid state recovery failed */
  };
  
  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) */
  	atomic_t count;
  };
  
  
  struct nfs4_exception {
  	long timeout;
  	int retry;
  	struct nfs4_state *state;
  	struct inode *inode;
  };
  
  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 *, struct rpc_cred *);
  	struct rpc_cred * (*get_clid_cred)(struct nfs_client *);
  	int (*reclaim_complete)(struct nfs_client *, struct rpc_cred *);
  	int (*detect_trunking)(struct nfs_client *, struct nfs_client **,
  		struct rpc_cred *);
  };
  
  struct nfs4_state_maintenance_ops {
  	int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *, unsigned);
  	struct rpc_cred * (*get_state_renewal_cred_locked)(struct nfs_client *);
  	int (*renew_lease)(struct nfs_client *, struct rpc_cred *);
  };
  
  extern const struct dentry_operations nfs4_dentry_operations;
  
  /* dir.c */
  int nfs_atomic_open(struct inode *, struct dentry *, struct file *,
  		    unsigned, umode_t, int *);
  
  /* super.c */
  extern struct file_system_type nfs4_fs_type;
  
  /* nfs4namespace.c */
  rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *);
  struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);
  struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
  			       struct nfs_fh *, struct nfs_fattr *);
  
  /* nfs4proc.c */
  extern int nfs4_proc_setclientid(struct nfs_client *, u32, unsigned short, struct rpc_cred *, struct nfs4_setclientid_res *);
  extern int nfs4_proc_setclientid_confirm(struct nfs_client *, struct nfs4_setclientid_res *arg, struct rpc_cred *);
  extern int nfs4_proc_get_rootfh(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *);
  extern int nfs4_proc_bind_conn_to_session(struct nfs_client *, struct rpc_cred *cred);
  extern int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred);
  extern int nfs4_destroy_clientid(struct nfs_client *clp);
  extern int nfs4_init_clientid(struct nfs_client *, struct rpc_cred *);
  extern int nfs41_init_clientid(struct nfs_client *, struct rpc_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 struct rpc_clnt *nfs4_proc_lookup_mountpoint(struct inode *, struct qstr *,
  			    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);
  
  #if defined(CONFIG_NFS_V4_1)
  static inline struct nfs4_session *nfs4_get_session(const struct nfs_server *server)
  {
  	return server->nfs_client->cl_session;
  }
  
  extern int nfs4_setup_sequence(const struct nfs_server *server,
  		struct nfs4_sequence_args *args, struct nfs4_sequence_res *res,
  		struct rpc_task *task);
  extern int nfs41_setup_sequence(struct nfs4_session *session,
  		struct nfs4_sequence_args *args, struct nfs4_sequence_res *res,
  		struct rpc_task *task);
  extern int nfs4_proc_create_session(struct nfs_client *, struct rpc_cred *);
  extern int nfs4_proc_destroy_session(struct nfs4_session *, struct rpc_cred *);
  extern int nfs4_proc_get_lease_time(struct nfs_client *clp,
  		struct nfs_fsinfo *fsinfo);
  extern int nfs4_proc_layoutcommit(struct nfs4_layoutcommit_data *data,
  				  bool sync);
  
  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;
  }
  #else /* CONFIG_NFS_v4_1 */
  static inline struct nfs4_session *nfs4_get_session(const struct nfs_server *server)
  {
  	return NULL;
  }
  
  static inline int nfs4_setup_sequence(const struct nfs_server *server,
  		struct nfs4_sequence_args *args, struct nfs4_sequence_res *res,
  		struct rpc_task *task)
  {
  	rpc_call_start(task);
  	return 0;
  }
  
  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;
  }
  #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 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 *);
  
  /* nfs4state.c */
  struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp);
  struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp);
  struct rpc_cred *nfs4_get_renew_cred_locked(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 **, struct rpc_cred *);
  #if defined(CONFIG_NFS_V4_1)
  struct rpc_cred *nfs4_get_exchange_id_cred(struct nfs_client *clp);
  int nfs41_discover_server_trunking(struct nfs_client *clp,
  			struct nfs_client **, struct rpc_cred *);
  extern void nfs4_schedule_session_recovery(struct nfs4_session *, int);
  extern void nfs41_server_notify_target_slotid_update(struct nfs_client *clp);
  extern void nfs41_server_notify_highest_slotid_update(struct nfs_client *clp);
  
  #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 *, struct rpc_cred *, gfp_t);
  extern void nfs4_put_state_owner(struct nfs4_state_owner *);
  extern void nfs4_purge_state_owners(struct nfs_server *);
  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 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 void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags);
  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(nfs4_stateid *, struct nfs4_state *,
  		fmode_t, const struct nfs_lockowner *);
  
  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 void nfs4_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp);
  
  extern const nfs4_stateid zero_stateid;
  
  /* nfs4super.c */
  struct nfs_mount_info;
  extern struct nfs_subversion nfs_v4;
  struct dentry *nfs4_try_mount(int, const char *, struct nfs_mount_info *, struct nfs_subversion *);
  extern bool nfs4_disable_idmapping;
  extern unsigned short max_session_slots;
  extern unsigned short send_implementation_id;
  
  #define NFS4_CLIENT_ID_UNIQ_LEN		(64)
  extern char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN];
  
  /* 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 struct rpc_procinfo nfs4_procedures[];
  
  struct nfs4_mount_data;
  
  /* callback_xdr.c */
  extern struct svc_version nfs4_callback_version1;
  extern struct svc_version nfs4_callback_version4;
  
  static inline void nfs4_stateid_copy(nfs4_stateid *dst, const nfs4_stateid *src)
  {
  	memcpy(dst, src, sizeof(*dst));
  }
  
  static inline bool nfs4_stateid_match(const nfs4_stateid *dst, const nfs4_stateid *src)
  {
  	return memcmp(dst, src, sizeof(*dst)) == 0;
  }
  
  static inline bool nfs4_valid_open_stateid(const struct nfs4_state *state)
  {
  	return test_bit(NFS_STATE_RECOVERY_FAILED, &state->flags) == 0;
  }
  
  #else
  
  #define nfs4_close_state(a, b) do { } while (0)
  #define nfs4_close_sync(a, b) do { } while (0)
  
  #endif /* CONFIG_NFS_V4 */
  #endif /* __LINUX_FS_NFS_NFS4_FS.H */
  