On Mon, 7 Feb 2022, Nitesh Shetty wrote: > Before enabling copy for dm target, check if underlaying devices and > dm target support copy. Avoid split happening inside dm target. > Fail early if the request needs split, currently spliting copy > request is not supported > > Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx> If a dm device is reconfigured, you must invalidate all the copy tokens that are in flight, otherwise they would copy stale data. I suggest that you create a global variable "atomic64_t dm_changed". In nvme_setup_copy_read you copy this variable to the token. In nvme_setup_copy_write you compare the variable with the value in the token and fail if there is mismatch. In dm.c:__bind you increase the variable, so that all the tokens will be invalidated if a dm table is changed. Mikulas
