--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2012-05-15  Pádraig Brady  <P@draigBrady.com>
+
+	fsusage: fix block size returned on older Linux 2.6
+
+	* lib/fsusage.c: Fall back to (struct statfs).f_frsize
+	which is available since Linux 2.6.
+	* m4/fsusage.m4 (STAT_STATFS2_FRSIZE): Always define
+	when the member is available so it can be used as a fallback.
+	* doc/posix-functions/statvfs.texi: Mention the hang issue
+	on Linux < 2.6.36.
+
 2012-05-14  Paul Eggert  <eggert@cs.ucla.edu>
 
 	bootstrap: suppress stderr chatter

--- a/doc/posix-functions/statvfs.texi
+++ b/doc/posix-functions/statvfs.texi
@@ -16,6 +16,11 @@
 This function is missing on some platforms:
 MacOS X 10.3, OpenBSD 3.8, mingw, MSVC 9.
 @item
+This function can hang if it stats all preceding
+entries in /proc/mounts, and any of those file systems
+are hard-mounted and not available.  This affects
+Linux < 2.6.36.
+@item
 On platforms where @code{f_blocks} in @samp{struct statvfs} is a 32-bit
 value, this function may not work correctly on files systems larger than
 4 TiB.  The fix is to use the @code{AC_SYS_LARGEFILE} macro.  This affects

--- a/lib/fsusage.c
+++ b/lib/fsusage.c
@@ -217,7 +217,16 @@
 
   fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize);
 
-#elif defined STAT_STATFS2_BSIZE        /* glibc/Linux, 4.3BSD, SunOS 4, \
+#elif defined STAT_STATFS2_FRSIZE        /* 2.6 < glibc/Linux < 2.6.36 */
+
+  struct statfs fsd;
+
+  if (statfs (file, &fsd) < 0)
+    return -1;
+
+  fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_frsize);
+
+#elif defined STAT_STATFS2_BSIZE        /* glibc/Linux < 2.6, 4.3BSD, SunOS 4, \
                                            MacOS X < 10.4, FreeBSD < 5.0, \
                                            NetBSD < 3.0, OpenBSD < 4.4 */
 

--- a/m4/fsusage.m4
+++ b/m4/fsusage.m4
@@ -128,6 +128,37 @@
   fi
 fi
 
+# Check for this unconditionally so we have a
+# good fallback on glibc/Linux > 2.6 < 2.6.36
+AC_MSG_CHECKING([for two-argument statfs with statfs.f_frsize member])
+AC_CACHE_VAL([fu_cv_sys_stat_statfs2_frsize],
+[AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#ifdef HAVE_SYS_PARAM_H
+#include <sys/param.h>
+#endif
+#ifdef HAVE_SYS_MOUNT_H
+#include <sys/mount.h>
+#endif
+#ifdef HAVE_SYS_VFS_H
+#include <sys/vfs.h>
+#endif
+  int
+  main ()
+  {
+  struct statfs fsd;
+  fsd.f_frsize = 0;
+  return statfs (".", &fsd) != 0;
+  }]])],
+  [fu_cv_sys_stat_statfs2_frsize=yes],
+  [fu_cv_sys_stat_statfs2_frsize=no],
+  [fu_cv_sys_stat_statfs2_frsize=no])])
+AC_MSG_RESULT([$fu_cv_sys_stat_statfs2_frsize])
+if test $fu_cv_sys_stat_statfs2_frsize = yes; then
+    AC_DEFINE([STAT_STATFS2_FRSIZE], [1],
+[  Define if statfs takes 2 args and struct statfs has a field named f_frsize.
+   (glibc/Linux > 2.6)])
+fi
+
 if test $ac_fsusage_space = no; then
   # glibc/Linux, MacOS X, FreeBSD < 5.0, NetBSD < 3.0, OpenBSD < 4.4.
   # (glibc/{Hurd,kFreeBSD}, FreeBSD >= 5.0, NetBSD >= 3.0,