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  */
  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 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
  52 int nfsd_file_cache_init(void);
  53 void nfsd_file_cache_purge(struct net *);
  54 void nfsd_file_cache_shutdown(void);
  55 int nfsd_file_cache_start_net(struct net *net);
  56 void nfsd_file_cache_shutdown_net(struct net *net);
  57 void nfsd_file_put(struct nfsd_file *nf);
  58 struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
  59 void nfsd_file_close_inode_sync(struct inode *inode);
  60 bool 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);
  63 int     nfsd_file_cache_stats_open(struct inode *, struct file *);
  64 #endif /* _FS_NFSD_FILECACHE_H */