sstate/lib.oe.path: Ensure file sparseness is preserved

Files when restored from sstate were missing their sparseness. Fix up various
functions to preserve this and make things more deterministic.

(From OE-Core rev: 055402e5504f041c346571e243c7cf0894955cad)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/sstate.bbclass

@@ -721,9 +721,9 @@ sstate_create_package () {
 	TFILE=`mktemp ${SSTATE_PKG}.XXXXXXXX`
 
         # Use pigz if available
-        OPT="-cz"
+        OPT="-czS"
         if [ -x "$(command -v pigz)" ]; then
-            OPT="-I pigz -c"
+            OPT="-I pigz -cS"
         fi
 
 	# Need to handle empty directories

meta/lib/oe/path.py

@@ -86,7 +86,7 @@ def copytree(src, dst):
     # This way we also preserve hardlinks between files in the tree.
 
     bb.utils.mkdirhier(dst)
-    cmd = "tar --xattrs --xattrs-include='*' -cf - -C %s -p . | tar --xattrs --xattrs-include='*' -xf - -C %s" % (src, dst)
+    cmd = "tar --xattrs --xattrs-include='*' -cf - -S -C %s -p . | tar --xattrs --xattrs-include='*' -xf - -C %s" % (src, dst)
     subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
 
 def copyhardlinktree(src, dst):
@@ -98,7 +98,7 @@ def copyhardlinktree(src, dst):
     if (os.stat(src).st_dev ==  os.stat(dst).st_dev):
         # Need to copy directories only with tar first since cp will error if two 
         # writers try and create a directory at the same time
-        cmd = "cd %s; find . -type d -print | tar --xattrs --xattrs-include='*' -cf - -C %s -p --no-recursion --files-from - | tar --xattrs --xattrs-include='*' -xhf - -C %s" % (src, src, dst)
+        cmd = "cd %s; find . -type d -print | tar --xattrs --xattrs-include='*' -cf - -S -C %s -p --no-recursion --files-from - | tar --xattrs --xattrs-include='*' -xhf - -C %s" % (src, src, dst)
         subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
         source = ''
         if os.path.isdir(src):