Ceph

Currently, cosd has this on startup:

    if (x != y) {
      dout(0) << "xattrs don't appear to work (" << strerror_r(errno, buf, sizeof(buf))
              << ") on " << fn << ", be sure to mount underlying file system with 'user_xattr' option" << dendl;
      return -errno;
    }

but mkcephfs just outputs

2011-03-28 13:23:23.596948 b77b16d0 OSD::mkfs: couldn't mount FileStore: error -95
2011-03-28 13:23:23.597008 b77b16d0  ** ERROR: error creating empty object store in /data/osd0: error 95: Operation not supported
failed: '/usr/bin/cosd -c /etc/ceph/ceph.conf --monmap /tmp/mkcephfs.DZdhzxPY5k/monmap.24380 -i 0 --mkfs --osd-data /data/osd0'

the log files will, however, contain

ceph version 0.25.2.commit: 07ee6311a607e5d9cf6e8054135c176289d64988.
process: cosd. pid: 24504
2011-03-28 13:23:23.596272 b77b16d0 -- :/24504 messenger.start
2011-03-28 13:23:23.596517 b77b16d0 -- :/24504 shutdown complete.
2011-03-28 13:23:23.596645 b77b16d0 filestore(/data/osd0) mkfs in /data/osd0
2011-03-28 13:23:23.596742 b77b16d0 filestore(/data/osd0) mkfs  removing old directory current
2011-03-28 13:23:23.596848 b77b16d0 filestore(/data/osd0) mkfs done in /data/osd0
2011-03-28 13:23:23.596922 b77b16d0 filestore(/data/osd0) xattrs don't appear to work (Operation not supported) on /data/osd0/fsid, be sure to mount underlying file system with 'user_xattr' option
2011-03-28 13:23:23.596948 b77b16d0 OSD::mkfs: couldn't mount FileStore: error -95
2011-03-28 13:23:23.597008 b77b16d0  ** ERROR: error creating empty object store in /data/osd0: error 95: Operation not supported

If it'd show an explicit mention of btrfs & user_xattr also on stderr, we'd have fewer confused users.