A larger set of xfstests passes to REFS than we realized (even more if non-default mount options, like modefromsid,idsfromsid are specified). For example I have been running this set: ./check -cifs cifs/001 generic/001 generic/002 generic/005 generic/006 generic/007 generic/008 generic/010 generic/011 generic/013 generic/014 generic/024 generic/028 generic/029 generic/030 generic/032 generic/033 generic/036 generic/069 generic/071 generic/074 generic/080 generic/084 generic/086 generic/095 generic/098 generic/100 generic/109 generic/113 generic/116 generic/118 generic/119 generic/121 generic/124 generic/125 generic/129 generic/132 generic/133 generic/135 generic/141 generic/142 generic/143 generic/146 generic/149 generic/150 generic/151 generic/152 generic/154 generic/155 generic/161 generic/162 generic/163 generic/164 generic/165 generic/166 generic/167 generic/169 generic/170 generic/178 generic/179 generic/180 generic/181 generic/182 generic/183 generic/185 generic/186 generic/187 generic/188 generic/189 generic/190 generic/191 generic/194 generic/195 generic/196 generic/197 generic/198 generic/201 generic/207 generic/208 generic/210 generic/211 generic/212 generic/213 generic/214 generic/215 generic/228 generic/236 generic/239 generic/241 generic/242 generic/243 generic/246 generic/247 generic/248 generic/249 generic/253 generic/254 generic/257 generic/258 generic/259 generic/284 generic/287 generic/289 generic/290 generic/297 generic/298 generic/308 generic/309 generic/310 generic/313 generic/315 generic/316 generic/323 generic/330 generic/332 generic/339 generic/340 generic/344 generic/345 generic/346 generic/349 generic/350 generic/354 generic/358 generic/359 generic/360 generic/373 generic/374 generic/391 generic/393 generic/394 generic/406 generic/407 generic/408 generic/412 generic/415 generic/420 generic/422 generic/428 generic/430 generic/431 generic/432 generic/433 generic/437 generic/438 generic/439 generic/443 generic/446 generic/451 generic/452 generic/460 generic/463 generic/464 generic/465 generic/504 generic/524 generic/528 generic/532 generic/544 generic/551 generic/565 generic/567 generic/568 generic/590 generic/591 generic/604 generic/609 generic/610 generic/612 generic/614 generic/615 We need to do additional testing with Ronnie's fcollapse and insert range patch set. REFS, like Samba on BTRFS, can run various testing which depend on reflink ("DUPLICATE_EXTENTS") so additional testing also needs to be done on Samba with btrfs to see if differences (indicating potential bugs). -- Thanks, Steve