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 */
20struct nfsd_file_mark {
21	struct fsnotify_mark	nfm_mark;
22	atomic_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 */
31struct nfsd_file {
32	struct hlist_node	nf_node;
33	struct list_head	nf_lru;
34	struct rcu_head		nf_rcu;
35	struct file		*nf_file;
36	const struct cred	*nf_cred;
37	struct net		*nf_net;
38#define NFSD_FILE_HASHED	(0)
39#define NFSD_FILE_PENDING	(1)
40#define NFSD_FILE_BREAK_READ	(2)
41#define NFSD_FILE_BREAK_WRITE	(3)
42#define NFSD_FILE_REFERENCED	(4)
43	unsigned long		nf_flags;
44	struct inode		*nf_inode;
45	unsigned int		nf_hashval;
46	atomic_t		nf_ref;
47	unsigned char		nf_may;
48	struct nfsd_file_mark	*nf_mark;
49};
50
51int nfsd_file_cache_init(void);
52void nfsd_file_cache_purge(struct net *);
53void nfsd_file_cache_shutdown(void);
54void nfsd_file_put(struct nfsd_file *nf);
55struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
56void nfsd_file_close_inode_sync(struct inode *inode);
57bool nfsd_file_is_cached(struct inode *inode);
58__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
59		  unsigned int may_flags, struct nfsd_file **nfp);
60int	nfsd_file_cache_stats_open(struct inode *, struct file *);
61#endif /* _FS_NFSD_FILECACHE_H */