#ifndef _FS_NFSD_FILECACHE_H
#define _FS_NFSD_FILECACHE_H

#include <linux/fsnotify_backend.h>

/*
 * Limit the time that the list_lru_one lock is held during
 * an LRU scan.
 */
#define NFSD_FILE_GC_BATCH     (16UL)

/*
 * This is the fsnotify_mark container that nfsd attaches to the files that it
 * is holding open. Note that we have a separate refcount here aside from the
 * one in the fsnotify_mark. We only want a single fsnotify_mark attached to
 * the inode, and for each nfsd_file to hold a reference to it.
 *
 * The fsnotify_mark is itself refcounted, but that's not sufficient to tell us
 * how to put that reference. If there are still outstanding nfsd_files that
 * reference the mark, then we would want to call fsnotify_put_mark on it.
 * If there were not, then we'd need to call fsnotify_destroy_mark. Since we
 * can't really tell the difference, we use the nfm_mark to keep track of how
 * many nfsd_files hold references to the mark. When that counter goes to zero
 * then we know to call fsnotify_destroy_mark on it.
 */
struct nfsd_file_mark {
        struct fsnotify_mark    nfm_mark;
        refcount_t              nfm_ref;
};

/*
 * A representation of a file that has been opened by knfsd. These are hashed
 * in the hashtable by inode pointer value. Note that this object doesn't
 * hold a reference to the inode by itself, so the nf_inode pointer should
 * never be dereferenced, only used for comparison.
 */
struct nfsd_file {
        struct rhlist_head      nf_rlist;
        void                    *nf_inode;
        struct file             *nf_file;
        const struct cred       *nf_cred;
        struct net              *nf_net;
#define NFSD_FILE_HASHED        (0)
#define NFSD_FILE_PENDING       (1)
#define NFSD_FILE_REFERENCED    (2)
#define NFSD_FILE_GC            (3)
#define NFSD_FILE_RECENT        (4)
        unsigned long           nf_flags;
        refcount_t              nf_ref;
        unsigned char           nf_may;

        struct nfsd_file_mark   *nf_mark;
        struct list_head        nf_lru;
        struct list_head        nf_gc;
        struct rcu_head         nf_rcu;
        ktime_t                 nf_birthtime;

        u32                     nf_dio_mem_align;
        u32                     nf_dio_offset_align;
        u32                     nf_dio_read_offset_align;
};

int nfsd_file_cache_init(void);
void nfsd_file_cache_purge(struct net *);
void nfsd_file_cache_shutdown(void);
int nfsd_file_cache_start_net(struct net *net);
void nfsd_file_cache_shutdown_net(struct net *net);
void nfsd_file_put(struct nfsd_file *nf);
struct net *nfsd_file_put_local(struct nfsd_file __rcu **nf);
struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
struct file *nfsd_file_file(struct nfsd_file *nf);
void nfsd_file_close_inode_sync(struct inode *inode);
void nfsd_file_net_dispose(struct nfsd_net *nn);
bool nfsd_file_is_cached(struct inode *inode);
__be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
                  unsigned int may_flags, struct nfsd_file **nfp);
__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
                  unsigned int may_flags, struct nfsd_file **nfp);
__be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
                  unsigned int may_flags, struct file *file,
                  struct nfsd_file **nfp);
__be32 nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
                               struct auth_domain *client, struct svc_fh *fhp,
                               unsigned int may_flags, struct nfsd_file **pnf);
__be32 nfsd_file_acquire_dir(struct svc_rqst *rqstp, struct svc_fh *fhp,
                  struct nfsd_file **pnf);
int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
#endif /* _FS_NFSD_FILECACHE_H */