overlay/017: create helpers to record and check inode numbers

Use helpers to records and check inode numbers so we can repeat
the same test after rename and mount cycle.

Suggested-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/overlay/017

@@ -72,32 +72,59 @@ mknod $lowerdir/blkdev b 1 1
 mknod $lowerdir/fifo p
 $here/src/af_unix $lowerdir/socket
 
+FILES="dir file symlink chrdev blkdev fifo socket"
+
+# Record inode numbers in format <ino> <basename>
+function record_inode_numbers()
+{
+	dir=$1
+	outfile=$2
+
+	for f in $FILES; do
+		ls -id $dir/$f
+	done | \
+	while read ino file; do
+		echo $ino `basename $file` >> $outfile
+	done
+}
+
+# Check inode numbers match recorder inode numbers
+function check_inode_numbers()
+{
+	dir=$1
+	before=$2
+	after=$3
+
+	record_inode_numbers $dir $after
+
+	# Test constant stat(2) st_ino -
+	#   Compare before..after - expect silence
+	# We use diff -u so out.bad will tell us which stage failed
+	diff -u $before $after
+
+	# Test constant readdir(3)/getdents(2) d_ino -
+	#   Expect to find file by inode number
+	cat $before | while read ino f; do
+		find $dir/ -maxdepth 1 -inum $ino | grep -q $f || \
+			echo "$f not found by ino $ino (from $before)"
+	done
+}
 
 _scratch_mount
 
 
 rm -f $tmp.*
 
-# Test stable stat(2) st_ino
+# Record inode numbers before copy up
+record_inode_numbers $SCRATCH_MNT $tmp.before
 
-# Record inode numbers before and after copy up
-for f in dir file symlink chrdev blkdev fifo socket; do
-	ls -id $SCRATCH_MNT/$f >> $tmp.before
+for f in $FILES; do
 	# chown -h modifies all those file types
 	chown -h 100 $SCRATCH_MNT/$f
-	ls -id $SCRATCH_MNT/$f >> $tmp.after
 done
 
-# Test stable readdir(3)/getdents(2) d_ino
-
-# find by inode number - expect to find file by inode number
-cat $tmp.before | while read ino f; do
-	find $SCRATCH_MNT/ -maxdepth 1 -inum $ino | grep -q $f || \
-		echo "$f not found by ino $ino"
-done
-
-# Compare before..after - expect silence
-diff $tmp.before $tmp.after
+# Compare inode numbers before/after copy up
+check_inode_numbers $SCRATCH_MNT $tmp.before $tmp.after_copyup
 
 echo "Silence is golden"
 status=0