Comment 5 for bug 224754

SRU Justification:

Impact: Unionfs cause kernel crash

Fix Description: This fixes a problem with chown'ing a file which has the suid bit set and has more than one hardlink on a read-only file system. The stacked nature of the unionfs means that the attribute changes pass through the lower level attr fs routines with the ATTR_MODE flag set when it's already been handled before in a stacked operation, so clear the ATTR_MODE flag. (This is the same fix as in the stacked ecrypt fs.)

Patch: http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-hardy-lum.git;a=commit;h=40b5f73849e523d7385d5e6272037eeaddef4ee2

TEST CASE: See https://bugs.edge.launchpad.net/ubuntu/+source/linux-ubuntu-modules-2.6.24/+bug/224754/comments/4