We can quickly get an estimate of how many blocks are available
for allocation restricted by quota and fs size respectively, using
the ap-allowed field in the gfs2_alloc_parms structure.
gfs2_quota_check() and gfs2_inplace_reserve() provide these values.
Once we have the total number of blocks
struct gfs2_alloc_parms is passed to gfs2_quota_check() and
gfs2_inplace_reserve() with ap-target containing the number of
blocks being requested for allocation in the current operation.
We add a new field to struct gfs2_alloc_parms called 'allowed'.
gfs2_quota_check() and gfs2_inplace_reserve()
This is a revised version of the patches required to properly fix the
fallocate quota issue described in bz1174295
patch1: This patch supplies gfs2_quota_check() with the number of blocks
the caller intends to allocate in the current operation, resulting
in a more accurate quota
