diff -urNp coreutils-8.20-orig/doc/coreutils.texi coreutils-8.20/doc/coreutils.texi

--- coreutils-8.20-orig/doc/coreutils.texi	2012-10-23 16:14:12.000000000 +0200

+++ coreutils-8.20/doc/coreutils.texi	2012-12-10 14:41:33.532650289 +0100

@@ -10597,6 +10597,14 @@ Normally the disk space is printed in un

 1024 bytes, but this can be overridden (@pxref{Block size}).

 Non-integer quantities are rounded up to the next higher unit.

+For bind mounts and without arguments, @command{df} only outputs the statistics

+for the first occurence of that device in the list of file systems (@var{mtab}),

+i.e., it hides duplicate entries, unless the @option{-a} option is specified.

+

+By default, @command{df} omits the early-boot pseudo file system type

+@samp{rootfs}, unless the @option{-a} option is specified or that file system

+type is explicitly to be included by using the @option{-t} option.

+

 @cindex disk device file

 @cindex device file, disk

 If an argument @var{file} is a disk device file containing a mounted

diff -urNp coreutils-8.20-orig/src/df.c coreutils-8.20/src/df.c

--- coreutils-8.20-orig/src/df.c	2012-10-23 16:14:12.000000000 +0200

+++ coreutils-8.20/src/df.c	2012-12-10 14:41:33.534649048 +0100

@@ -46,6 +46,17 @@

 /* If true, show inode information. */

 static bool inode_format;

+/* Filled with device numbers of examined file systems to avoid

+   duplicities in output.  */

+struct devlist

+{

+  dev_t dev_num;

+  struct devlist *next;

+};

+

+/* Store of already-processed device numbers.  */

+static struct devlist *devlist_head;

+

 /* If true, show even file systems with zero size or

    uninteresting types. */

 static bool show_all_fs;

@@ -57,6 +68,12 @@ static bool show_local_fs;

    command line argument -- even if it's a dummy (automounter) entry.  */

 static bool show_listed_fs;

+/* If true, include rootfs in the output.  */

+static bool show_rootfs;

+

+/* The literal name of the initial root file system.  */

+static char const *ROOTFS = "rootfs";

+

 /* Human-readable options for output.  */

 static int human_output_opts;

@@ -372,6 +389,29 @@ excluded_fstype (const char *fstype)

   return false;

 }

+/* Check if the device was already examined.  */

+

+static bool

+dev_examined (char const *mount_dir, char const *devname)

+{

+  struct stat buf;

+  if (-1 == stat (mount_dir, &buf))

+    return false;

+

+  struct devlist *devlist = devlist_head;

+  for ( ; devlist; devlist = devlist->next)

+    if (devlist->dev_num == buf.st_dev)

+      return true;

+

+  /* Add the device number to the global list devlist.  */

+  devlist = xmalloc (sizeof *devlist);

+  devlist->dev_num = buf.st_dev;

+  devlist->next = devlist_head;

+  devlist_head = devlist;

+

+  return false;

+}

+

 /* Return true if N is a known integer value.  On many file systems,

    UINTMAX_MAX represents an unknown value; on AIX, UINTMAX_MAX - 1

    represents unknown.  Use a rule that works on AIX file systems, and

@@ -496,6 +536,15 @@ get_dev (char const *disk, char const *m

   if (!selected_fstype (fstype) || excluded_fstype (fstype))

     return;

+  if (process_all && !show_all_fs && !show_listed_fs)

+    {

+      /* No arguments nor "df -a", then check if df has to ...  */

+      if (!show_rootfs && STREQ (disk, ROOTFS))

+        return; /* ... skip rootfs: (unless -trootfs is given.  */

+      if (dev_examined (mount_point, disk))

+        return; /* ... skip duplicate entries (bind mounts).  */

+    }

+

   /* If MOUNT_POINT is NULL, then the file system is not mounted, and this

      program reports on the file system that the special file is on.

      It would be better to report on the unmounted file system,

@@ -1005,6 +1054,7 @@ main (int argc, char **argv)

           /* Accept -F as a synonym for -t for compatibility with Solaris.  */

         case 't':

           add_fs_type (optarg);

+          show_rootfs = selected_fstype (ROOTFS);

           break;

         case 'v':		/* For SysV compatibility. */

@@ -1149,6 +1199,14 @@ main (int argc, char **argv)

      diagnostic, e.g., if all have been excluded.  */

   if (exit_status == EXIT_SUCCESS && ! file_systems_processed)

     error (EXIT_FAILURE, 0, _("no file systems processed"));

+  IF_LINT (

+    while (devlist_head)

+      {

+        struct devlist *devlist = devlist_head->next;

+        free (devlist_head);

+        devlist_head = devlist;

+      }

+    );

   exit (exit_status);

 }

diff -urNp coreutils-8.20-orig/tests/df/skip-duplicates.sh coreutils-8.20/tests/df/skip-duplicates.sh

--- coreutils-8.20-orig/tests/df/skip-duplicates.sh	1970-01-01 01:00:00.000000000 +0100

+++ coreutils-8.20/tests/df/skip-duplicates.sh	2012-12-10 14:41:33.535280173 +0100

@@ -0,0 +1,77 @@

+#!/bin/sh

+# Test df's behavior when the mount list contains duplicate entries.

+# This test is skipped on systems that lack LD_PRELOAD support; that's fine.

+

+# Copyright (C) 2012 Free Software Foundation, Inc.

+

+# This program is free software: you can redistribute it and/or modify

+# it under the terms of the GNU General Public License as published by

+# the Free Software Foundation, either version 3 of the License, or

+# (at your option) any later version.

+

+# This program is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+# GNU General Public License for more details.

+

+# You should have received a copy of the GNU General Public License

+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

+

+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src

+print_ver_ df

+

+df || skip_ "df fails"

+

+# Simulate an mtab file with two entries of the same device number.

+cat > k.c <<'EOF' || framework_failure_

+#include <stdio.h>

+#include <mntent.h>

+

+struct mntent *getmntent (FILE *fp)

+{

+  /* Prove that LD_PRELOAD works. */

+  static int done = 0;

+  if (!done)

+    {

+      fclose (fopen ("x", "w"));

+      ++done;

+    }

+

+  static struct mntent mntent;

+

+  while (done++ < 3)

+    {

+      mntent.mnt_fsname = "fsname";

+      mntent.mnt_dir = "/";

+      mntent.mnt_type = "-";

+

+      return &mntent;

+    }

+  return NULL;

+}

+EOF

+

+# Then compile/link it:

+gcc --std=gnu99 -shared -fPIC -ldl -O2 k.c -o k.so \

+  || skip_ "getmntent hack does not work on this platform"

+

+# Test if LD_PRELOAD works:

+LD_PRELOAD=./k.so df

+test -f x || skip_ "internal test failure: maybe LD_PRELOAD doesn't work?"

+

+# The fake mtab file should only contain 2 entries, both

+# having the same device number; thus the output should

+# consist of a header and one entry.

+LD_PRELOAD=./k.so df >out || fail=1

+test $(wc -l 

+

+# Ensure that filtering duplicates does not affect -a processing.

+LD_PRELOAD=./k.so df -a >out || fail=1

+test $(wc -l 

+

+# Ensure that filtering duplcates does not affect

+# argument processing (now without the fake getmntent()).

+df '.' '.' >out || fail=1

+test $(wc -l 

+

+Exit $fail

diff -urNp coreutils-8.20-orig/tests/df/skip-rootfs.sh coreutils-8.20/tests/df/skip-rootfs.sh

--- coreutils-8.20-orig/tests/df/skip-rootfs.sh	1970-01-01 01:00:00.000000000 +0100

+++ coreutils-8.20/tests/df/skip-rootfs.sh	2012-12-10 14:41:33.536310753 +0100

@@ -0,0 +1,46 @@

+#!/bin/sh

+# Test df's behavior for skipping the pseudo "rootfs" file system.

+

+# Copyright (C) 2012 Free Software Foundation, Inc.

+

+# This program is free software: you can redistribute it and/or modify

+# it under the terms of the GNU General Public License as published by

+# the Free Software Foundation, either version 3 of the License, or

+# (at your option) any later version.

+

+# This program is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+# GNU General Public License for more details.

+

+# You should have received a copy of the GNU General Public License

+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

+

+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src

+print_ver_ df

+

+df || skip_ "df fails"

+

+# Verify that rootfs is in mtab (and shown when the -a option is specified).

+df -a >out || fail=1

+grep '^rootfs' out || skip_ "no rootfs in mtab"

+

+# Ensure that rootfs is supressed when no options is specified.

+df >out || fail=1

+grep '^rootfs' out && { fail=1; cat out; }

+

+# Ensure that the rootfs is shown when explicitly specifying "-t rootfs".

+df -t rootfs >out || fail=1

+grep '^rootfs' out || { fail=1; cat out; }

+

+# Ensure that the rootfs is shown when explicitly specifying "-t rootfs",

+# even when the -a option is specified.

+df -t rootfs -a >out || fail=1

+grep '^rootfs' out || { fail=1; cat out; }

+

+# Ensure that the rootfs is omitted in all_fs mode when it is explicitly

+# black-listed.

+df -a -x rootfs >out || fail=1

+grep '^rootfs' out && { fail=1; cat out; }

+

+Exit $fail

diff -urNp coreutils-8.20-orig/tests/local.mk coreutils-8.20/tests/local.mk

--- coreutils-8.20-orig/tests/local.mk	2012-10-23 16:14:12.000000000 +0200

+++ coreutils-8.20/tests/local.mk	2012-12-10 14:41:33.536310753 +0100

@@ -456,6 +456,8 @@ all_tests =					\

   tests/df/unreadable.sh			\

   tests/df/total-unprocessed.sh			\

   tests/df/no-mtab-status.sh			\

+  tests/df/skip-duplicates.sh			\

+  tests/df/skip-rootfs.sh			\

   tests/dd/direct.sh				\

   tests/dd/misc.sh				\

   tests/dd/nocache.sh				\