If you say Y here, you will be able to set limits for disk usage on
a per user and/or a per group basis under XFS. XFS considers quota
information as filesystem metadata and uses journaling to provide a
higher level guarantee of consistency. The on-disk data format for
quota is also compatible with the IRIX version of XFS, allowing a
filesystem to be migrated between Linux and IRIX without any need
for conversion.

If unsure, say N. More comprehensive documentation can be found in
README.quota in the xfsprogs package. XFS quota can be used either
with or without the generic quota support enabled (CONFIG_QUOTA) -
they are completely independent subsystems.