LXR linux/fs/nfsd/filecache.h

   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        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 */
  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        refcount_t              nf_ref;
  47        unsigned char           nf_may;
  48        struct nfsd_file_mark   *nf_mark;
  49        struct rw_semaphore     nf_rwsem;
  50};
  51
  52int nfsd_file_cache_init(void);
  53void nfsd_file_cache_purge(struct net *);
  54void nfsd_file_cache_shutdown(void);
  55int nfsd_file_cache_start_net(struct net *net);
  56void nfsd_file_cache_shutdown_net(struct net *net);
  57void nfsd_file_put(struct nfsd_file *nf);
  58struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
  59void nfsd_file_close_inode_sync(struct inode *inode);
  60bool nfsd_file_is_cached(struct inode *inode);
  61__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
  62                  unsigned int may_flags, struct nfsd_file **nfp);
  63int     nfsd_file_cache_stats_open(struct inode *, struct file *);
  64#endif /* _FS_NFSD_FILECACHE_H */
  65