text: /* SPDX-License-Identifier: GPL-2.0 */
  /*
   * linux/fs/nfs/delegation.h
   *
   * Copyright (c) Trond Myklebust
   *
   * Definitions pertaining to NFS delegated files
   */
  #ifndef FS_NFS_DELEGATION_H
  #define FS_NFS_DELEGATION_H
  
  #if IS_ENABLED(CONFIG_NFS_V4)
  /*
   * NFSv4 delegation
   */
  struct nfs_delegation {
  	struct list_head super_list;
  	const struct cred *cred;
  	struct inode *inode;
  	nfs4_stateid stateid;
  	fmode_t type;
  	unsigned long pagemod_limit;
  	__u64 change_attr;
  	unsigned long flags;
  	spinlock_t lock;
  	struct rcu_head rcu;
  };
  
  enum {
  	NFS_DELEGATION_NEED_RECLAIM = 0,
  	NFS_DELEGATION_RETURN,
  	NFS_DELEGATION_RETURN_IF_CLOSED,
  	NFS_DELEGATION_REFERENCED,
  	NFS_DELEGATION_RETURNING,
  	NFS_DELEGATION_REVOKED,
  	NFS_DELEGATION_TEST_EXPIRED,
  	NFS_DELEGATION_INODE_FREEING,
  };
  
  int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
  		fmode_t type, const nfs4_stateid *stateid, unsigned long pagemod_limit);
  void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
  		fmode_t type, const nfs4_stateid *stateid, unsigned long pagemod_limit);
  int nfs4_inode_return_delegation(struct inode *inode);
  int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid);
  void nfs_inode_return_delegation_noreclaim(struct inode *inode);
  
  struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle);
  void nfs_server_return_all_delegations(struct nfs_server *);
  void nfs_expire_all_delegations(struct nfs_client *clp);
  void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags);
  void nfs_expire_unreferenced_delegations(struct nfs_client *clp);
  int nfs_client_return_marked_delegations(struct nfs_client *clp);
  int nfs_delegations_present(struct nfs_client *clp);
  void nfs_remove_bad_delegation(struct inode *inode, const nfs4_stateid *stateid);
  
  void nfs_delegation_mark_reclaim(struct nfs_client *clp);
  void nfs_delegation_reap_unclaimed(struct nfs_client *clp);
  
  void nfs_mark_test_expired_all_delegations(struct nfs_client *clp);
  void nfs_reap_expired_delegations(struct nfs_client *clp);
  
  /* NFSv4 delegation-related procedures */
  int nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred, const nfs4_stateid *stateid, int issync);
  int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid, fmode_t type);
  int nfs4_lock_delegation_recall(struct file_lock *fl, struct nfs4_state *state, const nfs4_stateid *stateid);
  bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags, nfs4_stateid *dst, const struct cred **cred);
  bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode);
  
  void nfs_mark_delegation_referenced(struct nfs_delegation *delegation);
  int nfs4_have_delegation(struct inode *inode, fmode_t flags);
  int nfs4_check_delegation(struct inode *inode, fmode_t flags);
  bool nfs4_delegation_flush_on_close(const struct inode *inode);
  void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
  		const nfs4_stateid *stateid);
  int nfs4_inode_make_writeable(struct inode *inode);
  
  #endif
  
  static inline int nfs_have_delegated_attributes(struct inode *inode)
  {
  	return NFS_PROTO(inode)->have_delegation(inode, FMODE_READ) &&
  		!(NFS_I(inode)->cache_validity & NFS_INO_REVAL_FORCED);
  }
  
  #endif
  