Updated version of Ronnie's patch for FALLOC_FL_INSERT_RANGE and
FALLOC_FL_COLLAPSE_RANGE attached (cleaned up the two redundant length
checks noticed out by Aurelien, and fixed the endian check warnings
pointed out by sparse).

They fix at least six xfstests (but still more xfstests to work
through that seem to have other new feature dependencies beyond
fcollapse)

# ./check -cifs generic/072 generic/145 generic/147 generic/153
generic/351 generic/458
FSTYP         -- cifs
PLATFORM      -- Linux/x86_64 smfrench-Virtual-Machine
5.12.0-051200rc4-generic #202103212230 SMP Sun Mar 21 22:33:27 UTC
2021

generic/072 7s ...  6s
generic/145 0s ...  1s
generic/147 1s ...  0s
generic/153 0s ...  1s
generic/351 5s ...  3s
generic/458 1s ...  1s
Ran: generic/072 generic/145 generic/147 generic/153 generic/351 generic/458
Passed all 6 tests
-- 
Thanks,

Steve