linux: add UMA stat for the file system where the prefs are stored

I'd like to see how common it is to use a network file system for
your home directory.  This would help evaluate how important it is
to support these users.

See also:
  http://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/b43d2905f079fa1c

Review URL: http://codereview.chromium.org/3187011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56786 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 82 insertions, 2 deletions

diff --git a/base/base.gypi b/base/base.gypi
index d6e13b5..383f645 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -77,6 +77,7 @@
           'file_util.cc',
           'file_util.h',
           'file_util_deprecated.h',
+          'file_util_linux.cc',
           'file_util_mac.mm',
           'file_util_posix.cc',
           'file_util_win.cc',
diff --git a/base/file_util.h b/base/file_util.h
index 91b16d2..ce30b5e 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -612,9 +612,29 @@ inline bool MakeFileUnreadable(const FilePath& path) {
   // is passed in. If it is 0 then the whole file is paged in. The step size
   // which indicates the number of bytes to skip after every page touched is
   // also passed in.
-  bool PreReadImage(const wchar_t* file_path, size_t size_to_read,
-                    size_t step_size);
+bool PreReadImage(const wchar_t* file_path, size_t size_to_read,
+                  size_t step_size);
 #endif  // OS_WIN
+
+#if defined(OS_LINUX)
+// Broad categories of file systems as returned by statfs() on Linux.
+enum FileSystemType {
+  FILE_SYSTEM_UNKNOWN,  // statfs failed.
+  FILE_SYSTEM_0,        // statfs.f_type == 0 means unknown, may indicate AFS.
+  FILE_SYSTEM_ORDINARY,       // on-disk filesystem like ext2
+  FILE_SYSTEM_NFS,
+  FILE_SYSTEM_SMB,
+  FILE_SYSTEM_CODA,
+  FILE_SYSTEM_MEMORY,         // in-memory file system
+  FILE_SYSTEM_OTHER,          // any other value.
+  FILE_SYSTEM_TYPE_COUNT
+};
+
+// Attempts determine the FileSystemType for |path|.
+// Returns false if |path| doesn't exist.
+bool GetFileSystemType(const FilePath& path, FileSystemType* type);
+#endif
+
 }  // namespace file_util
 
 // Deprecated functions have been moved to this separate header file,
diff --git a/base/file_util_linux.cc b/base/file_util_linux.cc
new file mode 100644
index 0000000..dd0c820
--- /dev/null
+++ b/base/file_util_linux.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/file_util.h"
+
+#include "base/file_path.h"
+
+#include <errno.h>
+#include <sys/vfs.h>
+
+namespace file_util {
+
+bool GetFileSystemType(const FilePath& path, FileSystemType* type) {
+  struct statfs statfs_buf;
+  if (statfs(path.value().c_str(), &statfs_buf) < 0) {
+    if (errno == ENOENT)
+      return false;
+    *type = FILE_SYSTEM_UNKNOWN;
+    return true;
+  }
+
+  // While you would think the possible values of f_type would be available
+  // in a header somewhere, it appears that is not the case.  These values
+  // are copied from the statfs man page.
+  switch (statfs_buf.f_type) {
+    case 0:
+      *type = FILE_SYSTEM_0;
+      break;
+    case 0xEF53:  // ext2, ext3.
+    case 0x4D44:  // dos
+    case 0x5346544E:  // NFTS
+    case 0x52654973:  // reiser
+    case 0x58465342:  // XFS
+    case 0x9123683E:  // btrfs
+    case 0x3153464A:  // JFS
+      *type = FILE_SYSTEM_ORDINARY;
+      break;
+    case 0x6969:  // NFS
+      *type = FILE_SYSTEM_NFS;
+      break;
+    case 0xFF534D42:  // CIFS
+    case 0x517B:  // SMB
+      *type = FILE_SYSTEM_SMB;
+      break;
+    case 0x73757245:  // Coda
+      *type = FILE_SYSTEM_CODA;
+      break;
+    case 0x858458f6:  // ramfs
+    case 0x01021994:  // tmpfs
+      *type = FILE_SYSTEM_MEMORY;
+      break;
+    default:
+      *type = FILE_SYSTEM_OTHER;
+  }
+  return true;
+}
+
+}  // namespace