1  #ifndef _FS_NFSD_FILECACHE_H
2  #define _FS_NFSD_FILECACHE_H
3  
4  #include <linux/fsnotify_backend.h>
5  
6  /*
7   * This is the fsnotify_mark container that nfsd attaches to the files that it
8   * is holding open. Note that we have a separate refcount here aside from the
9   * one in the fsnotify_mark. We only want a single fsnotify_mark attached to
10   * the inode, and for each nfsd_file to hold a reference to it.
11   *
12   * The fsnotify_mark is itself refcounted, but that's not sufficient to tell us
13   * how to put that reference. If there are still outstanding nfsd_files that
14   * reference the mark, then we would want to call fsnotify_put_mark on it.
15   * If there were not, then we'd need to call fsnotify_destroy_mark. Since we
16   * can't really tell the difference, we use the nfm_mark to keep track of how
17   * many nfsd_files hold references to the mark. When that counter goes to zero
18   * then we know to call fsnotify_destroy_mark on it.
19   */
20  struct nfsd_file_mark {
21  	struct fsnotify_mark	nfm_mark;
22  	refcount_t		nfm_ref;
23  };
24  
25  /*
26   * A representation of a file that has been opened by knfsd. These are hashed
27   * in the hashtable by inode pointer value. Note that this object doesn't
28   * hold a reference to the inode by itself, so the nf_inode pointer should
29   * never be dereferenced, only used for comparison.
30   */
31  struct nfsd_file {
32  	struct rhlist_head	nf_rlist;
33  	void			*nf_inode;
34  	struct file		*nf_file;
35  	const struct cred	*nf_cred;
36  	struct net		*nf_net;
37  #define NFSD_FILE_HASHED	(0)
38  #define NFSD_FILE_PENDING	(1)
39  #define NFSD_FILE_REFERENCED	(2)
40  #define NFSD_FILE_GC		(3)
41  	unsigned long		nf_flags;
42  	refcount_t		nf_ref;
43  	unsigned char		nf_may;
44  
45  	struct nfsd_file_mark	*nf_mark;
46  	struct list_head	nf_lru;
47  	struct list_head	nf_gc;
48  	struct rcu_head		nf_rcu;
49  	ktime_t			nf_birthtime;
50  };
51  
52  int nfsd_file_cache_init(void);
53  void nfsd_file_cache_purge(struct net *);
54  void nfsd_file_cache_shutdown(void);
55  int nfsd_file_cache_start_net(struct net *net);
56  void nfsd_file_cache_shutdown_net(struct net *net);
57  void nfsd_file_put(struct nfsd_file *nf);
58  void nfsd_file_put_local(struct nfsd_file *nf);
59  struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
60  struct file *nfsd_file_file(struct nfsd_file *nf);
61  void nfsd_file_close_inode_sync(struct inode *inode);
62  void nfsd_file_net_dispose(struct nfsd_net *nn);
63  bool nfsd_file_is_cached(struct inode *inode);
64  __be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
65  		  unsigned int may_flags, struct nfsd_file **nfp);
66  __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
67  		  unsigned int may_flags, struct nfsd_file **nfp);
68  __be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
69  		  unsigned int may_flags, struct file *file,
70  		  struct nfsd_file **nfp);
71  __be32 nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
72  			       struct auth_domain *client, struct svc_fh *fhp,
73  			       unsigned int may_flags, struct nfsd_file **pnf);
74  int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
75  #endif /* _FS_NFSD_FILECACHE_H */
76