filecache.h

 1#ifndef _FS_NFSD_FILECACHE_H
 2#define _FS_NFSD_FILECACHE_H
 3
 4#include <linux/fsnotify_backend.h>
 5
 6/*
 7 * Limit the time that the list_lru_one lock is held during
 8 * an LRU scan.
 9 */
10#define NFSD_FILE_GC_BATCH     (16UL)
11
12/*
13 * This is the fsnotify_mark container that nfsd attaches to the files that it
14 * is holding open. Note that we have a separate refcount here aside from the
15 * one in the fsnotify_mark. We only want a single fsnotify_mark attached to
16 * the inode, and for each nfsd_file to hold a reference to it.
17 *
18 * The fsnotify_mark is itself refcounted, but that's not sufficient to tell us
19 * how to put that reference. If there are still outstanding nfsd_files that
20 * reference the mark, then we would want to call fsnotify_put_mark on it.
21 * If there were not, then we'd need to call fsnotify_destroy_mark. Since we
22 * can't really tell the difference, we use the nfm_mark to keep track of how
23 * many nfsd_files hold references to the mark. When that counter goes to zero
24 * then we know to call fsnotify_destroy_mark on it.
25 */
26struct nfsd_file_mark {
27	struct fsnotify_mark	nfm_mark;
28	refcount_t		nfm_ref;
29};
30
31/*
32 * A representation of a file that has been opened by knfsd. These are hashed
33 * in the hashtable by inode pointer value. Note that this object doesn't
34 * hold a reference to the inode by itself, so the nf_inode pointer should
35 * never be dereferenced, only used for comparison.
36 */
37struct nfsd_file {
38	struct rhlist_head	nf_rlist;
39	void			*nf_inode;
40	struct file		*nf_file;
41	const struct cred	*nf_cred;
42	struct net		*nf_net;
43#define NFSD_FILE_HASHED	(0)
44#define NFSD_FILE_PENDING	(1)
45#define NFSD_FILE_REFERENCED	(2)
46#define NFSD_FILE_GC		(3)
47#define NFSD_FILE_RECENT	(4)
48	unsigned long		nf_flags;
49	refcount_t		nf_ref;
50	unsigned char		nf_may;
51
52	struct nfsd_file_mark	*nf_mark;
53	struct list_head	nf_lru;
54	struct list_head	nf_gc;
55	struct rcu_head		nf_rcu;
56	ktime_t			nf_birthtime;
57
58	u32			nf_dio_mem_align;
59	u32			nf_dio_offset_align;
60	u32			nf_dio_read_offset_align;
61};
62
63int nfsd_file_cache_init(void);
64void nfsd_file_cache_purge(struct net *);
65void nfsd_file_cache_shutdown(void);
66int nfsd_file_cache_start_net(struct net *net);
67void nfsd_file_cache_shutdown_net(struct net *net);
68void nfsd_file_put(struct nfsd_file *nf);
69struct net *nfsd_file_put_local(struct nfsd_file __rcu **nf);
70struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
71struct file *nfsd_file_file(struct nfsd_file *nf);
72void nfsd_file_close_inode_sync(struct inode *inode);
73void nfsd_file_net_dispose(struct nfsd_net *nn);
74bool nfsd_file_is_cached(struct inode *inode);
75__be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
76		  unsigned int may_flags, struct nfsd_file **nfp);
77__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
78		  unsigned int may_flags, struct nfsd_file **nfp);
79__be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
80		  unsigned int may_flags, struct file *file,
81		  struct nfsd_file **nfp);
82__be32 nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
83			       struct auth_domain *client, struct svc_fh *fhp,
84			       unsigned int may_flags, struct nfsd_file **pnf);
85__be32 nfsd_file_acquire_dir(struct svc_rqst *rqstp, struct svc_fh *fhp,
86		  struct nfsd_file **pnf);
87int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
88#endif /* _FS_NFSD_FILECACHE_H */