1 files changed, 60 insertions, 0 deletions

diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
new file mode 100644
index 000000000000..0c0c67166b87
--- /dev/null
+++ b/fs/nfsd/filecache.h
@@ -0,0 +1,60 @@
+#ifndef _FS_NFSD_FILECACHE_H
+#define _FS_NFSD_FILECACHE_H
+
+#include <linux/fsnotify_backend.h>
+
+/*
+ * 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;
+        atomic_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 hlist_node       nf_node;
+        struct list_head        nf_lru;
+        struct rcu_head         nf_rcu;
+        struct file             *nf_file;
+        const struct cred       *nf_cred;
+#define NFSD_FILE_HASHED        (0)
+#define NFSD_FILE_PENDING       (1)
+#define NFSD_FILE_BREAK_READ    (2)
+#define NFSD_FILE_BREAK_WRITE   (3)
+#define NFSD_FILE_REFERENCED    (4)
+        unsigned long           nf_flags;
+        struct inode            *nf_inode;
+        unsigned int            nf_hashval;
+        atomic_t                nf_ref;
+        unsigned char           nf_may;
+        struct nfsd_file_mark   *nf_mark;
+};
+
+int nfsd_file_cache_init(void);
+void nfsd_file_cache_purge(void);
+void nfsd_file_cache_shutdown(void);
+void nfsd_file_put(struct nfsd_file *nf);
+struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
+void nfsd_file_close_inode_sync(struct inode *inode);
+bool nfsd_file_is_cached(struct inode *inode);
+__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
+                  unsigned int may_flags, struct nfsd_file **nfp);
+int     nfsd_file_cache_stats_open(struct inode *, struct file *);
+#endif /* _FS_NFSD_FILECACHE_H */