stat reports wrong fundamental block size

From http://thread.gmane.org/gmane.comp.file-systems.fuse.devel/8042/focus=8052

The problem is this in stat.c:

/* Keep this conditional in sync with the similar conditional in
    ../m4/stat-prog.m4. */
#if (STAT_STATVFS \
&& (HAVE_STRUCT_STATVFS_F_BASETYPE || HAVE_STRUCT_STATVFS_F_FSTYPENAME \
      || (! HAVE_STRUCT_STATFS_F_FSTYPENAME && HAVE_STRUCT_STATVFS_F_TYPE)))
# define USE_STATVFS 1
#else
# define USE_STATVFS 0
#endif

It hasn't been kept in sync so USE_STATVFS is zero and so the f_frsize
field isn't used at all. I'm not sure what that conditional should be,
but none of those symbols are defined -- there's something wrong with
the configure script that I haven't looked into.

As far as I can see, there is no problem with code being out of sync.
If you can point to specifics, please let me know,
since I'm about to release coreutils-7.5 upstream.

However, note that with glibc and a linux kernel, the stat program
always uses statfs, and not statvfs. This is a deliberate decision
taken at configure time. Details in comments here:

    http://git.savannah.gnu.org/cgit/gnulib.git/tree/m4/fsusage.m4#n50

However, the version of statvfs that forced us into this corner
dates back to 2003:

    http://git.sv.gnu.org/cgit/gnulib.git/commit/?id=eda39b870b7a849271

If someone does the legwork to determine whether that statvfs bug has been
fixed, and if so, since when, we should be able to write a configure test
to use glibc's statvfs when it's known not to be buggy.

@Nikolaus: thank you for opening this bug and helping make Ubuntu better. In the future, please do not confirm your own bugs -- please see https://wiki.ubuntu.com/Bugs/Status for a quick explanation of bug stati.

@Jim: thank you for your quick response, it is appreciated. Given time, I will try to check on it.

Meanwhile: changing to Incomplete: this is, right now, the Right Way To Do It (tm), unless we can show statvfs now works, er, correctly.

@hggdh: I marked it as confirmed because it has been reproduced by other people who reported their findings on the link I provided.

I have written a short test program that just calls statvfs on a mountpoint and a FUSE filesystem that just hangs for 10 seconds when statvfs is called. According to my tests, the statvfs bug has been fixed:

$ ./hang_on_statvfs tmp/ # this fs will hang for 10 seconds on statvfs()
$ ./hello tmp2/ # this one won't
$ $ time ./stattest / # stattest just calls statvfs
Running statvfs('/')

real 0m0.002s
user 0m0.000s
sys 0m0.004s

$ time ./stattest tmp2/hello
Running statvfs('tmp2/hello')

real 0m0.002s
user 0m0.004s
sys 0m0.000s

$ time ./stattest tmp/hello
Running statvfs('tmp/hello')

real 0m10.002s
user 0m0.000s
sys 0m0.004s

I don't feel confident enough to replace my libc with older versions though to test since when this has been fixed.