xref: /OK3568_Linux_fs/kernel/fs/nfsd/filecache.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun #ifndef _FS_NFSD_FILECACHE_H
2*4882a593Smuzhiyun #define _FS_NFSD_FILECACHE_H
3*4882a593Smuzhiyun 
4*4882a593Smuzhiyun #include <linux/fsnotify_backend.h>
5*4882a593Smuzhiyun 
6*4882a593Smuzhiyun /*
7*4882a593Smuzhiyun  * This is the fsnotify_mark container that nfsd attaches to the files that it
8*4882a593Smuzhiyun  * is holding open. Note that we have a separate refcount here aside from the
9*4882a593Smuzhiyun  * one in the fsnotify_mark. We only want a single fsnotify_mark attached to
10*4882a593Smuzhiyun  * the inode, and for each nfsd_file to hold a reference to it.
11*4882a593Smuzhiyun  *
12*4882a593Smuzhiyun  * The fsnotify_mark is itself refcounted, but that's not sufficient to tell us
13*4882a593Smuzhiyun  * how to put that reference. If there are still outstanding nfsd_files that
14*4882a593Smuzhiyun  * reference the mark, then we would want to call fsnotify_put_mark on it.
15*4882a593Smuzhiyun  * If there were not, then we'd need to call fsnotify_destroy_mark. Since we
16*4882a593Smuzhiyun  * can't really tell the difference, we use the nfm_mark to keep track of how
17*4882a593Smuzhiyun  * many nfsd_files hold references to the mark. When that counter goes to zero
18*4882a593Smuzhiyun  * then we know to call fsnotify_destroy_mark on it.
19*4882a593Smuzhiyun  */
20*4882a593Smuzhiyun struct nfsd_file_mark {
21*4882a593Smuzhiyun 	struct fsnotify_mark	nfm_mark;
22*4882a593Smuzhiyun 	refcount_t		nfm_ref;
23*4882a593Smuzhiyun };
24*4882a593Smuzhiyun 
25*4882a593Smuzhiyun /*
26*4882a593Smuzhiyun  * A representation of a file that has been opened by knfsd. These are hashed
27*4882a593Smuzhiyun  * in the hashtable by inode pointer value. Note that this object doesn't
28*4882a593Smuzhiyun  * hold a reference to the inode by itself, so the nf_inode pointer should
29*4882a593Smuzhiyun  * never be dereferenced, only used for comparison.
30*4882a593Smuzhiyun  */
31*4882a593Smuzhiyun struct nfsd_file {
32*4882a593Smuzhiyun 	struct hlist_node	nf_node;
33*4882a593Smuzhiyun 	struct list_head	nf_lru;
34*4882a593Smuzhiyun 	struct rcu_head		nf_rcu;
35*4882a593Smuzhiyun 	struct file		*nf_file;
36*4882a593Smuzhiyun 	const struct cred	*nf_cred;
37*4882a593Smuzhiyun 	struct net		*nf_net;
38*4882a593Smuzhiyun #define NFSD_FILE_HASHED	(0)
39*4882a593Smuzhiyun #define NFSD_FILE_PENDING	(1)
40*4882a593Smuzhiyun #define NFSD_FILE_BREAK_READ	(2)
41*4882a593Smuzhiyun #define NFSD_FILE_BREAK_WRITE	(3)
42*4882a593Smuzhiyun #define NFSD_FILE_REFERENCED	(4)
43*4882a593Smuzhiyun 	unsigned long		nf_flags;
44*4882a593Smuzhiyun 	struct inode		*nf_inode;
45*4882a593Smuzhiyun 	unsigned int		nf_hashval;
46*4882a593Smuzhiyun 	refcount_t		nf_ref;
47*4882a593Smuzhiyun 	unsigned char		nf_may;
48*4882a593Smuzhiyun 	struct nfsd_file_mark	*nf_mark;
49*4882a593Smuzhiyun };
50*4882a593Smuzhiyun 
51*4882a593Smuzhiyun int nfsd_file_cache_init(void);
52*4882a593Smuzhiyun void nfsd_file_cache_purge(struct net *);
53*4882a593Smuzhiyun void nfsd_file_cache_shutdown(void);
54*4882a593Smuzhiyun int nfsd_file_cache_start_net(struct net *net);
55*4882a593Smuzhiyun void nfsd_file_cache_shutdown_net(struct net *net);
56*4882a593Smuzhiyun void nfsd_file_put(struct nfsd_file *nf);
57*4882a593Smuzhiyun struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
58*4882a593Smuzhiyun void nfsd_file_close_inode_sync(struct inode *inode);
59*4882a593Smuzhiyun bool nfsd_file_is_cached(struct inode *inode);
60*4882a593Smuzhiyun __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
61*4882a593Smuzhiyun 		  unsigned int may_flags, struct nfsd_file **nfp);
62*4882a593Smuzhiyun int	nfsd_file_cache_stats_open(struct inode *, struct file *);
63*4882a593Smuzhiyun #endif /* _FS_NFSD_FILECACHE_H */
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