Messages in this thread Patch in this message | | | Date | Tue, 30 Jun 2020 13:10:05 +0530 | From | Kanchan Joshi <> | Subject | Re: [PATCH v2 1/2] fs,block: Introduce RWF_ZONE_APPEND and handling in direct IO path |
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On Tue, Jun 30, 2020 at 12:37:07AM +0000, Damien Le Moal wrote: >On 2020/06/30 3:35, Kanchan Joshi wrote: >> On Fri, Jun 26, 2020 at 02:50:20AM +0000, Damien Le Moal wrote: >>> On 2020/06/26 2:18, Kanchan Joshi wrote: >>>> Introduce RWF_ZONE_APPEND flag to represent zone-append. User-space >>>> sends this with write. Add IOCB_ZONE_APPEND which is set in >>>> kiocb->ki_flags on receiving RWF_ZONE_APPEND. >>>> Make direct IO submission path use IOCB_ZONE_APPEND to send bio with >>>> append op. Direct IO completion returns zone-relative offset, in sector >>>> unit, to upper layer using kiocb->ki_complete interface. >>>> Report error if zone-append is requested on regular file or on sync >>>> kiocb (i.e. one without ki_complete). >>>> >>>> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> >>>> Signed-off-by: SelvaKumar S <selvakuma.s1@samsung.com> >>>> Signed-off-by: Arnav Dawn <a.dawn@samsung.com> >>>> Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com> >>>> Signed-off-by: Javier Gonzalez <javier.gonz@samsung.com> >>>> --- >>>> fs/block_dev.c | 28 ++++++++++++++++++++++++---- >>>> include/linux/fs.h | 9 +++++++++ >>>> include/uapi/linux/fs.h | 5 ++++- >>>> 3 files changed, 37 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/fs/block_dev.c b/fs/block_dev.c >>>> index 47860e5..5180268 100644 >>>> --- a/fs/block_dev.c >>>> +++ b/fs/block_dev.c >>>> @@ -185,6 +185,10 @@ static unsigned int dio_bio_write_op(struct kiocb *iocb) >>>> /* avoid the need for a I/O completion work item */ >>>> if (iocb->ki_flags & IOCB_DSYNC) >>>> op |= REQ_FUA; >>>> + >>>> + if (iocb->ki_flags & IOCB_ZONE_APPEND) >>>> + op |= REQ_OP_ZONE_APPEND; >>> >>> This is wrong. REQ_OP_WRITE is already set in the declaration of "op". How can >>> this work ? >> REQ_OP_ZONE_APPEND will override the REQ_WRITE op, while previously set op >> flags (REQ_FUA etc.) will be retained. But yes, this can be made to look >> cleaner. >> V3 will include the other changes you pointed out. Thanks for the review. >> > >REQ_OP_WRITE and REQ_OP_ZONE_APPEND are different bits, so there is no >"override". A well formed BIO bi_opf is one op+flags. Specifying multiple OP >codes does not make sense.
one op+flags behavior is retained here. OP is not about bits (op flags are). Had it been, REQ_OP_WRITE (value 1) can not be differentiated from REQ_OP_ZONE_APPEND (value 13). We do not do "bio_op(bio) & REQ_OP_WRITE", rather we look at the absolute value "bio_op(bio) == REQ_OP_WRITE".
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