Here, /var/tmp is on an nfs4 filesystem and /tmp is a tmpfs filesystem. $ touch /var/tmp/foo $ cp -p /var/tmp/foo /tmp
cp: preserving permissions for ‘/tmp/foo’: Operation not supported --preserve=mode has the same result --no-preserve=xattr has no effect With nfs4 filesystems, files the system.nfs4_acl extended attribute is always set, representing at least the traditional user, group and mode settings but system.nfs4_acl can not be set on other filesystems. The copy_reg() function sets the traditional user, group and mode of the destination before trying to copy the acl with xcopy_acl(). Including system.nfs4_acl in /etc/xattr.conf has no effect as xcopy_acl() does not check /etc/xattr.conf. To be clear, the destination file does get its mode set correctly (if there are no extra entries in the acl), but cp exits with error status even if system.nfs4_acl has never been explicitly set. This breaks scripts that check for cp exit status. It is not clear exactly what the correct behaviour is since in some circumstances it would be important to fail if access control lists are not copied successfully. Maybe system.nfs4_acl should be parsed to see if there are any additional entries beyond A::OWNER@, A::GROUP@ and A::EVERYONE@? Or at least provide a way to suppress trying to copying acls, perhaps --no-preserve=acl.
