On 10/26/21 11:19 AM, James Bottomley wrote: > On Tue, 2021-10-26 at 09:36 -0700, Bart Van Assche wrote: >> On 10/26/21 12:12 AM, Christoph Hellwig wrote: >>> The HPB support added this merge window is fundanetally flawed as >>> it >> ^^^^^^^^^^^^ >> fundanetally -> >> fundamentally >> >> Since the implementation can be reworked not to use >> blk_insert_cloned_request() I'm not sure using the word >> "fundamentally" is appropriate. > > I'm not so sure about that. The READ BUFFER implementation runs from a > work queue and looks fine. The WRITE BUFFER implementation is trying > to spawn a second command to precede the queued command which is a > fundamental problem for the block API. It's not clear to me that the > WRITE BUFFER can be fixed because of the tying to the sent command ... > but like I said, the standard is proprietary so I can't look at it to > see if there are alternative ways of achieving the same effect. Is there a model in which this can actually work? If not, or if we aren't sure, I think we'd be better off just reverting the parts involved with that block layer misuse. Simply marking it broken is a half measure that doesn't really solve anything (except send a message). IMHO, it should be reverted and the clone usage we currently export be moved into dm for now. That'll prevent further abuse of this in the future. -- Jens Axboe
