quote Andreas in bug 20128:

Current ext3 code limits the size of individual objects to 2TB. This assumption
has been hard-coded into the client by use of LUSTRE_STRIPE_MAXBYTES in
lov_alloc_memmd(). For ext4- and DMU-based OSTs this assumption is incorrect.

We need to be able to convey the maximum object size from the OST to the client
via obd_connect_data. This can be extracted from the OST superblock
sb->s_maxbytes and sent to clients that send a new OBD_CONNECT_MAXBYTES flag to
fill in an ocd_maxbytes field at connect time. The minimum of the per-OSC
maxbytes values should be used to determine the lov_maxbytes and lli_maxbytes.

Make sure not to conflict with any fields/flags in the obd_connect_data or
OBD_CONNECT between branches...