sstate.bbclass: make hard links for staging files

Make hard links for staging files instead of copy to save the disk space
(3G will be saved for a core-image-sato build), and it doesn't affect
much on the build time.

The following directories are affected:
1) The sysroot
2) The DEPLOY_DIR
3) The pkgdata

[YOCTO #4372]

(From OE-Core rev: 5853e0f482b22258c909268fe71673a29e31989b)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/meta/lib/oe/path.py b/meta/lib/oe/path.py
index faa0f61fab..4f8b66c2f3 100644
--- a/meta/lib/oe/path.py
+++ b/meta/lib/oe/path.py
@@ -85,13 +85,18 @@ def copytree(src, dst):
     check_output(cmd, shell=True, stderr=subprocess.STDOUT)
 
 def copyhardlinktree(src, dst):
+    """ Make the hard link when possible, otherwise copy. """
     bb.utils.mkdirhier(dst)
+    src_bak = src
     if os.path.isdir(src):
         if not len(os.listdir(src)):
             return      
         src = src + "/*"
-    cmd = 'cp -al %s %s' % (src, dst)
-    check_output(cmd, shell=True, stderr=subprocess.STDOUT)
+    if (os.stat(src_bak).st_dev ==  os.stat(dst).st_dev):
+        cmd = 'cp -afl %s %s' % (src, dst)
+        check_output(cmd, shell=True, stderr=subprocess.STDOUT)
+    else:
+        copytree(src_bak, dst)
 
 def remove(path, recurse=True):
     """Equivalent to rm -f or rm -rf"""