1 files changed, 95 insertions, 0 deletions
diff --git a/src/os/FDCache.h b/src/os/FDCache.h
new file mode 100644
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--- /dev/null
+++ b/src/os/FDCache.h
@@ -0,0 +1,95 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2013 Inktank Storage, Inc.
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef CEPH_FDCACHE_H
+#define CEPH_FDCACHE_H
+
+#include <memory>
+#include <errno.h>
+#include <cstdio>
+#include "hobject.h"
+#include "common/Mutex.h"
+#include "common/Cond.h"
+#include "common/shared_cache.hpp"
+#include "include/compat.h"
+
+/**
+ * FD Cache
+ */
+class FDCache : public md_config_obs_t {
+  /**
+   * FD
+   *
+   * Wrapper for an fd.  Destructor closes the fd.
+   */
+  class FD {
+  public:
+    const int fd;
+    FD(int _fd) : fd(_fd) {
+      assert(_fd >= 0);
+    }
+    int operator*() const {
+      return fd;
+    }
+    ~FD() {
+      TEMP_FAILURE_RETRY(::close(fd));
+    }
+  };
+
+  SharedLRU<hobject_t, FD> registry;
+  CephContext *cct;
+public:
+  FDCache(CephContext *cct) : cct(cct) {
+    assert(cct);
+    cct->_conf->add_observer(this);
+    registry.set_size(cct->_conf->filestore_fd_cache_size);
+  }
+  ~FDCache() {
+    cct->_conf->remove_observer(this);
+  }
+  typedef std::tr1::shared_ptr<FD> FDRef;
+
+  FDRef lookup(const hobject_t &hoid) {
+    return registry.lookup(hoid);
+  }
+
+  FDRef add(const hobject_t &hoid, int fd) {
+    return registry.add(hoid, new FD(fd));
+  }
+
+  /// clear cached fd for hoid, subsequent lookups will get an empty FD
+  void clear(const hobject_t &hoid) {
+    registry.clear(hoid);
+    assert(!registry.lookup(hoid));
+  }
+
+  /// md_config_obs_t
+  const char** get_tracked_conf_keys() const {
+    static const char* KEYS[] = {
+      "filestore_fd_cache_size",
+      NULL
+    };
+    return KEYS;
+  }
+  void handle_conf_change(const md_config_t *conf,
+			  const std::set<std::string> &changed) {
+    if (changed.count("filestore_fd_cache_size")) {
+      registry.set_size(conf->filestore_fd_cache_size);
+    }
+  }
+
+};
+typedef FDCache::FDRef FDRef;
+
+#endif