>From decfe8df670818aa36637470bc38f221d49704b7 Mon Sep 17 00:00:00 2001
From: Ondrej Oprala <address@hidden>
Date: Thu, 24 Jan 2013 17:28:54 +0100
Subject: [PATCH] df: prefer fullpath entries when deduplicating

* src/df.c (struct devlist): Add a new element for storing
pointers to mount_entry structures.
(dev_approved): Check if a device is in the global devlist.
(dev_examine): Renamed from dev_examined, the function now
favors entries with a '/' character in me_devname or those
with the shortest me_mountdir string, if multiple entries
fulfill the first condition.
(get_all_entries): Call dev_examine and dev_approved if
appropriate.
(get_dev): Do not call dev_examined.
* tests/df/skip-duplicates.sh: Add tests.
---
 src/df.c                    | 45 +++++++++++++++++++++++++++++++++++++--------
 tests/df/skip-duplicates.sh | 18 ++++++++++++++----
 2 files changed, 51 insertions(+), 12 deletions(-)

diff --git a/src/df.c b/src/df.c
index 9523cc1..89bc93f 100644
--- a/src/df.c
+++ b/src/df.c
@@ -48,6 +48,7 @@
 struct devlist
 {
   dev_t dev_num;
+  struct mount_entry *me;
   struct devlist *next;
 };
 
@@ -609,24 +610,44 @@ excluded_fstype (const char *fstype)
 /* Check if the device was already examined.  */
 
 static bool
-dev_examined (char const *mount_dir, char const *devname)
+dev_approved (const struct mount_entry *me)
+{
+  struct devlist *devlist = devlist_head;
+  for ( ; devlist; devlist = devlist->next)
+    if (devlist->me == me)
+      return true;
+
+  return false;
+}
+
+static int
+dev_examine (struct mount_entry *me)
 {
   struct stat buf;
-  if (-1 == stat (mount_dir, &buf))
-    return false;
+  if (-1 == stat (me->me_mountdir, &buf))
+    return -1;
 
   struct devlist *devlist = devlist_head;
   for ( ; devlist; devlist = devlist->next)
     if (devlist->dev_num == buf.st_dev)
-      return true;
+    {
+      if ((!strchr (devlist->me->me_devname, '/')
+            && strchr (me->me_devname, '/'))
+          || (strchr (devlist->me->me_devname, '/')
+            && strchr (me->me_devname, '/')
+            && strlen (devlist->me->me_mountdir) > strlen (me->me_mountdir)))
+          devlist->me = me;
+
+      return 0;
+    }
 
   /* Add the device number to the global list devlist.  */
   devlist = xmalloc (sizeof *devlist);
+  devlist->me = me;
   devlist->dev_num = buf.st_dev;
   devlist->next = devlist_head;
   devlist_head = devlist;
-
-  return false;
+  return 0;
 }
 
 /* Return true if N is a known integer value.  On many file systems,
@@ -803,8 +824,6 @@ get_dev (char const *disk, char const *mount_point,
       /* 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
@@ -1133,9 +1152,19 @@ get_all_entries (void)
 {
   struct mount_entry *me;
 
+  if (!show_rootfs && !show_all_fs && !show_listed_fs)
+  {
+    for (me = mount_list; me; me = me->me_next)
+      dev_examine (me);
+  }
+
   for (me = mount_list; me; me = me->me_next)
+  {
+    if (!show_rootfs && !show_all_fs && !show_listed_fs && !dev_approved (me))
+      continue;
     get_dev (me->me_devname, me->me_mountdir, NULL, me->me_type,
              me->me_dummy, me->me_remote, NULL, true);
+  }
 }
 
 /* Add FSTYPE to the list of file system types to display.  */
diff --git a/tests/df/skip-duplicates.sh b/tests/df/skip-duplicates.sh
index 31ab014..20f3910 100755
--- a/tests/df/skip-duplicates.sh
+++ b/tests/df/skip-duplicates.sh
@@ -39,10 +39,15 @@ struct mntent *getmntent (FILE *fp)
 
   static struct mntent mntent;
 
-  while (done++ < 3)
+  while (done++ < 4)
     {
-      mntent.mnt_fsname = "fsname";
-      mntent.mnt_dir = "/";
+      /* File system - Mounted on
+         fsname       /
+         /fsname      /root
+         /fsname      /
+      */
+      mntent.mnt_fsname = (done == 2) ? "fsname" : "/fsname";
+      mntent.mnt_dir = (done == 3) ? "/root" : "/";
       mntent.mnt_type = "-";
 
       return &mntent;
@@ -65,9 +70,14 @@ test -f x || skip_ "internal test failure: maybe LD_PRELOAD doesn't work?"
 LD_PRELOAD=./k.so df >out || fail=1
 test $(wc -l <out) -eq 2 || { fail=1; cat out; }
 
+# df should also prefer "/fsname" over "fsname"
+test $(grep -c '/fsname' <out) -eq 1 || { fail=1; cat out; }
+# ... and "/fsname" with '/' as Mounted on over '/root'
+test $(grep -c '/root' <out) -eq 0 || { fail=1; cat out; }
+
 # Ensure that filtering duplicates does not affect -a processing.
 LD_PRELOAD=./k.so df -a >out || fail=1
-test $(wc -l <out) -eq 3 || { fail=1; cat out; }
+test $(wc -l <out) -eq 4 || { fail=1; cat out; }
 
 # Ensure that filtering duplcates does not affect
 # argument processing (now without the fake getmntent()).
-- 
1.7.11.7