xref: /linux/fs/nfsd/filecache.h (revision 09e61efd884ca68a768717d60858f138685b161b)
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 rhash_head	nf_rhash;
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_REFERENCED	(2)
41 #define NFSD_FILE_GC		(3)
42 	unsigned long		nf_flags;
43 	struct inode		*nf_inode;	/* don't deref */
44 	refcount_t		nf_ref;
45 	unsigned char		nf_may;
46 	struct nfsd_file_mark	*nf_mark;
47 	ktime_t			nf_birthtime;
48 };
49 
50 int nfsd_file_cache_init(void);
51 void nfsd_file_cache_purge(struct net *);
52 void nfsd_file_cache_shutdown(void);
53 int nfsd_file_cache_start_net(struct net *net);
54 void nfsd_file_cache_shutdown_net(struct net *net);
55 void nfsd_file_put(struct nfsd_file *nf);
56 struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
57 void nfsd_file_close_inode_sync(struct inode *inode);
58 bool nfsd_file_is_cached(struct inode *inode);
59 __be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
60 		  unsigned int may_flags, struct nfsd_file **nfp);
61 __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
62 		  unsigned int may_flags, struct nfsd_file **nfp);
63 __be32 nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
64 		  unsigned int may_flags, struct nfsd_file **nfp);
65 int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
66 #endif /* _FS_NFSD_FILECACHE_H */
67