• Miklos Szeredi's avatar
    ovl: ignore failure to copy up unknown xattrs · c61ca557
    Miklos Szeredi authored
    This issue came up with NFSv4 as the lower layer, which generates
    "system.nfs4_acl" xattrs (even for plain old unix permissions).  Prior to
    this patch this prevented copy-up from succeeding.
    The overlayfs permission model mandates that permissions are checked
    locally for the task and remotely for the mounter(*).  NFS4 ACLs are not
    supported by the Linux kernel currently, hence they cannot be enforced
    locally.  Which means it is indifferent whether this attribute is copied or
    Generalize this to any xattr that is not used in access checking (i.e. it's
    not a POSIX ACL and not in the "security." namespace).
    Incidentally, best effort copying of xattrs seems to also be the behavior
    of "cp -a", which is what overlayfs tries to mimic.
    (*) Documentation/filesystems/overlayfs.txt#Permission model
    Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
copy_up.c 21.9 KB