On Wed, Mar 12, 2025 at 02:57:38PM +0000, John Garry wrote: > > > I do admit that the checks are a bit uneven, i.e. check vs > > > IOMAP_DIO_ATOMIC_SW and IOCB_ATOMIC > > > > > > If we want a flag to set REQ_ATOMIC from the FS then we need > > > IOMAP_DIO_BIO_ATOMIC, and that would set IOMAP_BIO_ATOMIC. Is that better? > > > > My expectation from a very cursory view is that iomap would be that > > there is a IOMAP_F_REQ_ATOMIC that is set in ->iomap_begin and which > > would make the core iomap code set REQ_ATOMIC on the bio for that > > iteration. > > but we still need to tell ->iomap_begin about IOCB_ATOMIC, hence Yeah, ->iomap_begin can't directly look at the iocb. > IOMAP_DIO_BIO_ATOMIC which sets IOMAP_BIO_ATOMIC. > > We can't allow __iomap_dio_rw() check IOCB_ATOMIC only (and set > IOMAP_BIO_ATOMIC), as this is the common path for COW and regular atomic > write Well, I'd imagine __iomap_dio_rw just sets IOMAP_ATOMIC from IOCB_ATOMIC and then it's up to file system internal state if it wants to set IOMAP_F_REQ_ATOMIC based on that, i.e. the actual setting of IOMAP_F_REQ_ATOMIC is fully controlled by the file system and not by the iomap core.
