Problems with cephfs, rsync and xattr because cephfs internal xattrs are exposed to clients.

[Michael Wyraz <michael@wyraz.de>]

Hi,

I do rsync based backups against a cephfs. If I do sync xattrs, rsync 
tries to delete ceph-internal xattrs (e.g. ceph.dir.entries) which fails 
with an error. xattrs does not get synchronized in this case.
IMO the problem is, that ceph's internal attributes are exposed to the 
mounted fileystem (I can do "getfattr -n ceph.dir.entries *" on the 
mounted cephfs and get results). So rsync sees these xattrs and tries to 
remove it.

Example output:

    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.entries")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.files")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.subdirs")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.rentries")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.rfiles")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.rsubdirs")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.rbytes")
    failed: Operation not supported (95)
    rsync: rsync_xal_set:
    lremovexattr(""/backups/2016-05-31_00-09-32/etc/acpi/events"","ceph.dir.rctime")
    failed: Operation not supported (95)

Kind regards,
Michael.