text: /*
   *  pNFS client data structures.
   *
   *  Copyright (c) 2002
   *  The Regents of the University of Michigan
   *  All Rights Reserved
   *
   *  Dean Hildebrand <dhildebz@umich.edu>
   *
   *  Permission is granted to use, copy, create derivative works, and
   *  redistribute this software and such derivative works for any purpose,
   *  so long as the name of the University of Michigan is not used in
   *  any advertising or publicity pertaining to the use or distribution
   *  of this software without specific, written prior authorization. If
   *  the above copyright notice or any other identification of the
   *  University of Michigan is included in any copy of any portion of
   *  this software, then the disclaimer below must also be included.
   *
   *  This software is provided as is, without representation or warranty
   *  of any kind either express or implied, including without limitation
   *  the implied warranties of merchantability, fitness for a particular
   *  purpose, or noninfringement.  The Regents of the University of
   *  Michigan shall not be liable for any damages, including special,
   *  indirect, incidental, or consequential damages, with respect to any
   *  claim arising out of or in connection with the use of the software,
   *  even if it has been or is hereafter advised of the possibility of
   *  such damages.
   */
  
  #ifndef FS_NFS_PNFS_H
  #define FS_NFS_PNFS_H
  
  #include <linux/nfs_fs.h>
  #include <linux/nfs_page.h>
  #include <linux/workqueue.h>
  
  enum {
  	NFS_LSEG_VALID = 0,	/* cleared when lseg is recalled/returned */
  	NFS_LSEG_ROC,		/* roc bit received from server */
  	NFS_LSEG_LAYOUTCOMMIT,	/* layoutcommit bit set for layoutcommit */
  	NFS_LSEG_LAYOUTRETURN,	/* layoutreturn bit set for layoutreturn */
  };
  
  /* Individual ip address */
  struct nfs4_pnfs_ds_addr {
  	struct sockaddr_storage	da_addr;
  	size_t			da_addrlen;
  	struct list_head	da_node;  /* nfs4_pnfs_dev_hlist dev_dslist */
  	char			*da_remotestr;	/* human readable addr+port */
  };
  
  struct nfs4_pnfs_ds {
  	struct list_head	ds_node;  /* nfs4_pnfs_dev_hlist dev_dslist */
  	char			*ds_remotestr;	/* comma sep list of addrs */
  	struct list_head	ds_addrs;
  	struct nfs_client	*ds_clp;
  	atomic_t		ds_count;
  	unsigned long		ds_state;
  #define NFS4DS_CONNECTING	0	/* ds is establishing connection */
  };
  
  struct pnfs_layout_segment {
  	struct list_head pls_list;
  	struct list_head pls_lc_list;
  	struct pnfs_layout_range pls_range;
  	atomic_t pls_refcount;
  	u32 pls_seq;
  	unsigned long pls_flags;
  	struct pnfs_layout_hdr *pls_layout;
  	struct work_struct pls_work;
  };
  
  enum pnfs_try_status {
  	PNFS_ATTEMPTED     = 0,
  	PNFS_NOT_ATTEMPTED = 1,
  	PNFS_TRY_AGAIN     = 2,
  };
  
  #ifdef CONFIG_NFS_V4_1
  
  #define LAYOUT_NFSV4_1_MODULE_PREFIX "nfs-layouttype4"
  
  /*
   * Default data server connection timeout and retrans vaules.
   * Set by module parameters dataserver_timeo and dataserver_retrans.
   */
  #define NFS4_DEF_DS_TIMEO   600 /* in tenths of a second */
  #define NFS4_DEF_DS_RETRANS 5
  
  /* error codes for internal use */
  #define NFS4ERR_RESET_TO_MDS   12001
  #define NFS4ERR_RESET_TO_PNFS  12002
  
  enum {
  	NFS_LAYOUT_RO_FAILED = 0,	/* get ro layout failed stop trying */
  	NFS_LAYOUT_RW_FAILED,		/* get rw layout failed stop trying */
  	NFS_LAYOUT_BULK_RECALL,		/* bulk recall affecting layout */
  	NFS_LAYOUT_RETURN,		/* layoutreturn in progress */
  	NFS_LAYOUT_RETURN_LOCK,		/* Serialise layoutreturn */
  	NFS_LAYOUT_RETURN_REQUESTED,	/* Return this layout ASAP */
  	NFS_LAYOUT_INVALID_STID,	/* layout stateid id is invalid */
  	NFS_LAYOUT_FIRST_LAYOUTGET,	/* Serialize first layoutget */
  };
  
  enum layoutdriver_policy_flags {
  	/* Should the pNFS client commit and return the layout upon truncate to
  	 * a smaller size */
  	PNFS_LAYOUTRET_ON_SETATTR	= 1 << 0,
  	PNFS_LAYOUTRET_ON_ERROR		= 1 << 1,
  	PNFS_READ_WHOLE_PAGE		= 1 << 2,
  };
  
  struct nfs4_deviceid_node;
  
  /* Per-layout driver specific registration structure */
  struct pnfs_layoutdriver_type {
  	struct list_head pnfs_tblid;
  	const u32 id;
  	const char *name;
  	struct module *owner;
  	unsigned flags;
  	unsigned max_deviceinfo_size;
  
  	int (*set_layoutdriver) (struct nfs_server *, const struct nfs_fh *);
  	int (*clear_layoutdriver) (struct nfs_server *);
  
  	struct pnfs_layout_hdr * (*alloc_layout_hdr) (struct inode *inode, gfp_t gfp_flags);
  	void (*free_layout_hdr) (struct pnfs_layout_hdr *);
  
  	struct pnfs_layout_segment * (*alloc_lseg) (struct pnfs_layout_hdr *layoutid, struct nfs4_layoutget_res *lgr, gfp_t gfp_flags);
  	void (*free_lseg) (struct pnfs_layout_segment *lseg);
  	void (*add_lseg) (struct pnfs_layout_hdr *layoutid,
  			struct pnfs_layout_segment *lseg,
  			struct list_head *free_me);
  
  	void (*return_range) (struct pnfs_layout_hdr *lo,
  			      struct pnfs_layout_range *range);
  
  	/* test for nfs page cache coalescing */
  	const struct nfs_pageio_ops *pg_read_ops;
  	const struct nfs_pageio_ops *pg_write_ops;
  
  	struct pnfs_ds_commit_info *(*get_ds_info) (struct inode *inode);
  	void (*mark_request_commit) (struct nfs_page *req,
  				     struct pnfs_layout_segment *lseg,
  				     struct nfs_commit_info *cinfo,
  				     u32 ds_commit_idx);
  	void (*clear_request_commit) (struct nfs_page *req,
  				      struct nfs_commit_info *cinfo);
  	int (*scan_commit_lists) (struct nfs_commit_info *cinfo,
  				  int max);
  	void (*recover_commit_reqs) (struct list_head *list,
  				     struct nfs_commit_info *cinfo);
  	struct nfs_page * (*search_commit_reqs)(struct nfs_commit_info *cinfo,
  						struct page *page);
  	int (*commit_pagelist)(struct inode *inode,
  			       struct list_head *mds_pages,
  			       int how,
  			       struct nfs_commit_info *cinfo);
  
  	int (*sync)(struct inode *inode, bool datasync);
  
  	/*
  	 * Return PNFS_ATTEMPTED to indicate the layout code has attempted
  	 * I/O, else return PNFS_NOT_ATTEMPTED to fall back to normal NFS
  	 */
  	enum pnfs_try_status (*read_pagelist)(struct nfs_pgio_header *);
  	enum pnfs_try_status (*write_pagelist)(struct nfs_pgio_header *, int);
  
  	void (*free_deviceid_node) (struct nfs4_deviceid_node *);
  	struct nfs4_deviceid_node * (*alloc_deviceid_node)
  			(struct nfs_server *server, struct pnfs_device *pdev,
  			gfp_t gfp_flags);
  
  	void (*encode_layoutreturn) (struct pnfs_layout_hdr *layoutid,
  				     struct xdr_stream *xdr,
  				     const struct nfs4_layoutreturn_args *args);
  
  	void (*cleanup_layoutcommit) (struct nfs4_layoutcommit_data *data);
  	int (*prepare_layoutcommit) (struct nfs4_layoutcommit_args *args);
  	void (*encode_layoutcommit) (struct pnfs_layout_hdr *lo,
  				     struct xdr_stream *xdr,
  				     const struct nfs4_layoutcommit_args *args);
  	int (*prepare_layoutstats) (struct nfs42_layoutstat_args *args);
  	void (*cleanup_layoutstats) (struct nfs42_layoutstat_data *data);
  };
  
  struct pnfs_layout_hdr {
  	atomic_t		plh_refcount;
  	atomic_t		plh_outstanding; /* number of RPCs out */
  	struct list_head	plh_layouts;   /* other client layouts */
  	struct list_head	plh_bulk_destroy;
  	struct list_head	plh_segs;      /* layout segments list */
  	unsigned long		plh_block_lgets; /* block LAYOUTGET if >0 */
  	unsigned long		plh_retry_timestamp;
  	unsigned long		plh_flags;
  	nfs4_stateid		plh_stateid;
  	u32			plh_barrier; /* ignore lower seqids */
  	u32			plh_return_seq;
  	enum pnfs_iomode	plh_return_iomode;
  	loff_t			plh_lwb; /* last write byte for layoutcommit */
  	struct rpc_cred		*plh_lc_cred; /* layoutcommit cred */
  	struct inode		*plh_inode;
  };
  
  struct pnfs_device {
  	struct nfs4_deviceid dev_id;
  	unsigned int  layout_type;
  	unsigned int  mincount;
  	unsigned int  maxcount;	/* gdia_maxcount */
  	struct page **pages;
  	unsigned int  pgbase;
  	unsigned int  pglen;	/* reply buffer length */
  	unsigned char nocache : 1;/* May not be cached */
  };
  
  #define NFS4_PNFS_GETDEVLIST_MAXNUM 16
  
  struct pnfs_devicelist {
  	unsigned int		eof;
  	unsigned int		num_devs;
  	struct nfs4_deviceid	dev_id[NFS4_PNFS_GETDEVLIST_MAXNUM];
  };
  
  extern int pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *);
  extern void pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *);
  
  /* nfs4proc.c */
  extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
  				   struct pnfs_device *dev,
  				   struct rpc_cred *cred);
  extern struct pnfs_layout_segment* nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout, gfp_t gfp_flags);
  extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp, bool sync);
  
  /* pnfs.c */
  void pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo);
  void pnfs_put_lseg(struct pnfs_layout_segment *lseg);
  void pnfs_put_lseg_locked(struct pnfs_layout_segment *lseg);
  
  void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, struct nfs_fsinfo *);
  void unset_pnfs_layoutdriver(struct nfs_server *);
  void pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *, struct nfs_page *);
  int pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc);
  void pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
  			        struct nfs_page *req, u64 wb_size);
  void pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *);
  int pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc);
  size_t pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
  			    struct nfs_page *prev, struct nfs_page *req);
  void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg);
  struct pnfs_layout_segment *pnfs_layout_process(struct nfs4_layoutget *lgp);
  void pnfs_free_lseg_list(struct list_head *tmp_list);
  void pnfs_destroy_layout(struct nfs_inode *);
  void pnfs_destroy_all_layouts(struct nfs_client *);
  int pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
  		struct nfs_fsid *fsid,
  		bool is_recall);
  int pnfs_destroy_layouts_byclid(struct nfs_client *clp,
  		bool is_recall);
  void pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo);
  void pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo,
  			     const nfs4_stateid *new,
  			     bool update_barrier);
  int pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
  				struct list_head *tmp_list,
  				const struct pnfs_layout_range *recall_range,
  				u32 seq);
  int pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
  				struct list_head *tmp_list,
  				const struct pnfs_layout_range *recall_range,
  				u32 seq);
  int pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
  		struct list_head *lseg_list);
  bool pnfs_roc(struct inode *ino);
  void pnfs_roc_release(struct inode *ino);
  void pnfs_roc_set_barrier(struct inode *ino, u32 barrier);
  void pnfs_roc_get_barrier(struct inode *ino, u32 *barrier);
  bool pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task);
  void pnfs_set_layoutcommit(struct inode *, struct pnfs_layout_segment *, loff_t);
  void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data);
  int pnfs_layoutcommit_inode(struct inode *inode, bool sync);
  int pnfs_generic_sync(struct inode *inode, bool datasync);
  int pnfs_nfs_generic_sync(struct inode *inode, bool datasync);
  int _pnfs_return_layout(struct inode *);
  int pnfs_commit_and_return_layout(struct inode *);
  void pnfs_ld_write_done(struct nfs_pgio_header *);
  void pnfs_ld_read_done(struct nfs_pgio_header *);
  void pnfs_read_resend_pnfs(struct nfs_pgio_header *);
  struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
  					       struct nfs_open_context *ctx,
  					       loff_t pos,
  					       u64 count,
  					       enum pnfs_iomode iomode,
  					       bool strict_iomode,
  					       gfp_t gfp_flags);
  void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo);
  
  void pnfs_generic_layout_insert_lseg(struct pnfs_layout_hdr *lo,
  		   struct pnfs_layout_segment *lseg,
  		   bool (*is_after)(const struct pnfs_layout_range *lseg_range,
  			   const struct pnfs_layout_range *old),
  		   bool (*do_merge)(struct pnfs_layout_segment *lseg,
  			   struct pnfs_layout_segment *old),
  		   struct list_head *free_me);
  
  void nfs4_deviceid_mark_client_invalid(struct nfs_client *clp);
  int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *);
  int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *);
  struct nfs4_threshold *pnfs_mdsthreshold_alloc(void);
  void pnfs_error_mark_layout_for_return(struct inode *inode,
  				       struct pnfs_layout_segment *lseg);
  /* nfs4_deviceid_flags */
  enum {
  	NFS_DEVICEID_INVALID = 0,       /* set when MDS clientid recalled */
  	NFS_DEVICEID_UNAVAILABLE,	/* device temporarily unavailable */
  	NFS_DEVICEID_NOCACHE,		/* device may not be cached */
  };
  
  /* pnfs_dev.c */
  struct nfs4_deviceid_node {
  	struct hlist_node		node;
  	struct hlist_node		tmpnode;
  	const struct pnfs_layoutdriver_type *ld;
  	const struct nfs_client		*nfs_client;
  	unsigned long 			flags;
  	unsigned long			timestamp_unavailable;
  	struct nfs4_deviceid		deviceid;
  	struct rcu_head			rcu;
  	atomic_t			ref;
  };
  
  struct nfs4_deviceid_node *
  nfs4_find_get_deviceid(struct nfs_server *server,
  		const struct nfs4_deviceid *id, struct rpc_cred *cred,
  		gfp_t gfp_mask);
  void nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *, const struct nfs_client *, const struct nfs4_deviceid *);
  void nfs4_init_deviceid_node(struct nfs4_deviceid_node *, struct nfs_server *,
  			     const struct nfs4_deviceid *);
  bool nfs4_put_deviceid_node(struct nfs4_deviceid_node *);
  void nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node);
  bool nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node);
  void nfs4_deviceid_purge_client(const struct nfs_client *);
  
  /* pnfs_nfs.c */
  void pnfs_generic_clear_request_commit(struct nfs_page *req,
  				       struct nfs_commit_info *cinfo);
  void pnfs_generic_commit_release(void *calldata);
  void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data);
  void pnfs_generic_rw_release(void *data);
  void pnfs_generic_recover_commit_reqs(struct list_head *dst,
  				      struct nfs_commit_info *cinfo);
  int pnfs_generic_commit_pagelist(struct inode *inode,
  				 struct list_head *mds_pages,
  				 int how,
  				 struct nfs_commit_info *cinfo,
  				 int (*initiate_commit)(struct nfs_commit_data *data,
  							int how));
  int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo, int max);
  void pnfs_generic_write_commit_done(struct rpc_task *task, void *data);
  void nfs4_pnfs_ds_put(struct nfs4_pnfs_ds *ds);
  struct nfs4_pnfs_ds *nfs4_pnfs_ds_add(struct list_head *dsaddrs,
  				      gfp_t gfp_flags);
  void nfs4_pnfs_v3_ds_connect_unload(void);
  void nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
  			  struct nfs4_deviceid_node *devid, unsigned int timeo,
  			  unsigned int retrans, u32 version, u32 minor_version,
  			  rpc_authflavor_t au_flavor);
  struct nfs4_pnfs_ds_addr *nfs4_decode_mp_ds_addr(struct net *net,
  						 struct xdr_stream *xdr,
  						 gfp_t gfp_flags);
  void pnfs_layout_mark_request_commit(struct nfs_page *req,
  				     struct pnfs_layout_segment *lseg,
  				     struct nfs_commit_info *cinfo,
  				     u32 ds_commit_idx);
  
  static inline bool nfs_have_layout(struct inode *inode)
  {
  	return NFS_I(inode)->layout != NULL;
  }
  
  static inline bool pnfs_layout_is_valid(const struct pnfs_layout_hdr *lo)
  {
  	return test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags) == 0;
  }
  
  static inline struct nfs4_deviceid_node *
  nfs4_get_deviceid(struct nfs4_deviceid_node *d)
  {
  	atomic_inc(&d->ref);
  	return d;
  }
  
  static inline struct pnfs_layout_segment *
  pnfs_get_lseg(struct pnfs_layout_segment *lseg)
  {
  	if (lseg) {
  		atomic_inc(&lseg->pls_refcount);
  		smp_mb__after_atomic();
  	}
  	return lseg;
  }
  
  static inline bool
  pnfs_is_valid_lseg(struct pnfs_layout_segment *lseg)
  {
  	return test_bit(NFS_LSEG_VALID, &lseg->pls_flags) != 0;
  }
  
  /* Return true if a layout driver is being used for this mountpoint */
  static inline int pnfs_enabled_sb(struct nfs_server *nfss)
  {
  	return nfss->pnfs_curr_ld != NULL;
  }
  
  static inline int
  pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how,
  		 struct nfs_commit_info *cinfo)
  {
  	if (cinfo->ds == NULL || cinfo->ds->ncommitting == 0)
  		return PNFS_NOT_ATTEMPTED;
  	return NFS_SERVER(inode)->pnfs_curr_ld->commit_pagelist(inode, mds_pages, how, cinfo);
  }
  
  static inline struct pnfs_ds_commit_info *
  pnfs_get_ds_info(struct inode *inode)
  {
  	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
  
  	if (ld == NULL || ld->get_ds_info == NULL)
  		return NULL;
  	return ld->get_ds_info(inode);
  }
  
  static inline void
  pnfs_generic_mark_devid_invalid(struct nfs4_deviceid_node *node)
  {
  	set_bit(NFS_DEVICEID_INVALID, &node->flags);
  }
  
  static inline bool
  pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
  			 struct nfs_commit_info *cinfo, u32 ds_commit_idx)
  {
  	struct inode *inode = d_inode(req->wb_context->dentry);
  	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
  
  	if (lseg == NULL || ld->mark_request_commit == NULL)
  		return false;
  	ld->mark_request_commit(req, lseg, cinfo, ds_commit_idx);
  	return true;
  }
  
  static inline bool
  pnfs_clear_request_commit(struct nfs_page *req, struct nfs_commit_info *cinfo)
  {
  	struct inode *inode = d_inode(req->wb_context->dentry);
  	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
  
  	if (ld == NULL || ld->clear_request_commit == NULL)
  		return false;
  	ld->clear_request_commit(req, cinfo);
  	return true;
  }
  
  static inline int
  pnfs_scan_commit_lists(struct inode *inode, struct nfs_commit_info *cinfo,
  		       int max)
  {
  	if (cinfo->ds == NULL || cinfo->ds->nwritten == 0)
  		return 0;
  	else
  		return NFS_SERVER(inode)->pnfs_curr_ld->scan_commit_lists(cinfo, max);
  }
  
  static inline struct nfs_page *
  pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
  			struct page *page)
  {
  	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
  
  	if (ld == NULL || ld->search_commit_reqs == NULL)
  		return NULL;
  	return ld->search_commit_reqs(cinfo, page);
  }
  
  /* Should the pNFS client commit and return the layout upon a setattr */
  static inline bool
  pnfs_ld_layoutret_on_setattr(struct inode *inode)
  {
  	if (!pnfs_enabled_sb(NFS_SERVER(inode)))
  		return false;
  	return NFS_SERVER(inode)->pnfs_curr_ld->flags &
  		PNFS_LAYOUTRET_ON_SETATTR;
  }
  
  static inline bool
  pnfs_ld_read_whole_page(struct inode *inode)
  {
  	if (!pnfs_enabled_sb(NFS_SERVER(inode)))
  		return false;
  	return NFS_SERVER(inode)->pnfs_curr_ld->flags & PNFS_READ_WHOLE_PAGE;
  }
  
  static inline int
  pnfs_sync_inode(struct inode *inode, bool datasync)
  {
  	if (!pnfs_enabled_sb(NFS_SERVER(inode)))
  		return 0;
  	return NFS_SERVER(inode)->pnfs_curr_ld->sync(inode, datasync);
  }
  
  static inline bool
  pnfs_layoutcommit_outstanding(struct inode *inode)
  {
  	struct nfs_inode *nfsi = NFS_I(inode);
  
  	return test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags) != 0 ||
  		test_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags) != 0;
  }
  
  static inline int pnfs_return_layout(struct inode *ino)
  {
  	struct nfs_inode *nfsi = NFS_I(ino);
  	struct nfs_server *nfss = NFS_SERVER(ino);
  
  	if (pnfs_enabled_sb(nfss) && nfsi->layout)
  		return _pnfs_return_layout(ino);
  
  	return 0;
  }
  
  static inline bool
  pnfs_use_threshold(struct nfs4_threshold **dst, struct nfs4_threshold *src,
  		   struct nfs_server *nfss)
  {
  	return (dst && src && src->bm != 0 && nfss->pnfs_curr_ld &&
  					nfss->pnfs_curr_ld->id == src->l_type);
  }
  
  static inline u64
  pnfs_calc_offset_end(u64 offset, u64 len)
  {
  	if (len == NFS4_MAX_UINT64 || len >= NFS4_MAX_UINT64 - offset)
  		return NFS4_MAX_UINT64;
  	return offset + len - 1;
  }
  
  static inline u64
  pnfs_calc_offset_length(u64 offset, u64 end)
  {
  	if (end == NFS4_MAX_UINT64 || end <= offset)
  		return NFS4_MAX_UINT64;
  	return 1 + end - offset;
  }
  
  static inline void
  pnfs_copy_range(struct pnfs_layout_range *dst,
  		const struct pnfs_layout_range *src)
  {
  	memcpy(dst, src, sizeof(*dst));
  }
  
  extern unsigned int layoutstats_timer;
  
  #ifdef NFS_DEBUG
  void nfs4_print_deviceid(const struct nfs4_deviceid *dev_id);
  #else
  static inline void nfs4_print_deviceid(const struct nfs4_deviceid *dev_id)
  {
  }
  
  #endif /* NFS_DEBUG */
  #else  /* CONFIG_NFS_V4_1 */
  
  static inline bool nfs_have_layout(struct inode *inode)
  {
  	return false;
  }
  
  static inline void pnfs_destroy_all_layouts(struct nfs_client *clp)
  {
  }
  
  static inline void pnfs_destroy_layout(struct nfs_inode *nfsi)
  {
  }
  
  static inline struct pnfs_layout_segment *
  pnfs_get_lseg(struct pnfs_layout_segment *lseg)
  {
  	return NULL;
  }
  
  static inline void pnfs_put_lseg(struct pnfs_layout_segment *lseg)
  {
  }
  
  static inline int pnfs_return_layout(struct inode *ino)
  {
  	return 0;
  }
  
  static inline int pnfs_commit_and_return_layout(struct inode *inode)
  {
  	return 0;
  }
  
  static inline bool
  pnfs_ld_layoutret_on_setattr(struct inode *inode)
  {
  	return false;
  }
  
  static inline bool
  pnfs_ld_read_whole_page(struct inode *inode)
  {
  	return false;
  }
  
  static inline int
  pnfs_sync_inode(struct inode *inode, bool datasync)
  {
  	return 0;
  }
  
  static inline bool
  pnfs_layoutcommit_outstanding(struct inode *inode)
  {
  	return false;
  }
  
  
  static inline bool
  pnfs_roc(struct inode *ino)
  {
  	return false;
  }
  
  static inline void
  pnfs_roc_release(struct inode *ino)
  {
  }
  
  static inline void
  pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
  {
  }
  
  static inline void
  pnfs_roc_get_barrier(struct inode *ino, u32 *barrier)
  {
  }
  
  static inline bool
  pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task)
  {
  	return false;
  }
  
  static inline void set_pnfs_layoutdriver(struct nfs_server *s,
  					 const struct nfs_fh *mntfh,
  					 struct nfs_fsinfo *fsinfo)
  {
  }
  
  static inline void unset_pnfs_layoutdriver(struct nfs_server *s)
  {
  }
  
  static inline int
  pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how,
  		 struct nfs_commit_info *cinfo)
  {
  	return PNFS_NOT_ATTEMPTED;
  }
  
  static inline struct pnfs_ds_commit_info *
  pnfs_get_ds_info(struct inode *inode)
  {
  	return NULL;
  }
  
  static inline bool
  pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
  			 struct nfs_commit_info *cinfo, u32 ds_commit_idx)
  {
  	return false;
  }
  
  static inline bool
  pnfs_clear_request_commit(struct nfs_page *req, struct nfs_commit_info *cinfo)
  {
  	return false;
  }
  
  static inline int
  pnfs_scan_commit_lists(struct inode *inode, struct nfs_commit_info *cinfo,
  		       int max)
  {
  	return 0;
  }
  
  static inline struct nfs_page *
  pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
  			struct page *page)
  {
  	return NULL;
  }
  
  static inline int pnfs_layoutcommit_inode(struct inode *inode, bool sync)
  {
  	return 0;
  }
  
  static inline bool
  pnfs_use_threshold(struct nfs4_threshold **dst, struct nfs4_threshold *src,
  		   struct nfs_server *nfss)
  {
  	return false;
  }
  
  static inline struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
  {
  	return NULL;
  }
  
  static inline void nfs4_pnfs_v3_ds_connect_unload(void)
  {
  }
  
  #endif /* CONFIG_NFS_V4_1 */
  
  #if IS_ENABLED(CONFIG_NFS_V4_2)
  int pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags);
  #else
  static inline int
  pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
  {
  	return 0;
  }
  #endif
  
  #endif /* FS_NFS_PNFS_H */
  