Current xfs_quota (I pulled xfsprogs today) seems not be able to the users
managed by LDAP. There is no patch since I'm not good at LDAP and don't know
the root cause yet ;-(
Step to reproduce(in this case, "sat" is the user managed by LDAP):
# uname -r
# mount -o loop,usrquota xfs.img mnt
# xfsprogs/quota/xfs_quota -xc "limit bsoft=10M bhard=10M sat" /dev/loop0
xfs_quota: invalid user name: sat #
# su sat
But this user acutally exists.
The kernel is a bit old, but I suspect this is a userland problem.
I'll try to reproduce it on 3.7.0-rc6 too.