On Thu, Jan 11, 2024 at 08:36:55AM +0100, Christoph Hellwig wrote: > REQ_OP_FLUSH is only for internal use in the blk-mq and request based > drivers. File systems and other block layer consumers must use > REQ_OP_WRITE | REQ_PREFLUSH as documented in > Documentation/block/writeback_cache_control.rst. > > While REQ_OP_FLUSH appears to work for blk-mq drivers it does not > get the proper flush state machine handling, and completely fails > for any bio based drivers, including all the stacking drivers. The > block layer will also get a check in 6.8 to reject this use case > entirely. > > [Note: completely untested, but as this never got fixed since the > original bug report in November: > > https://bugzilla.kernel.org/show_bug.cgi?id=218184 > > and the the discussion in December: > > https://lore.kernel.org/all/20231221053016.72cqcfg46vxwohcj@xxxxxxxxxxxxxx/T/ > > this seems to be best way to force it] > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> Hey Christoph, thanks - applied.