On Wed 03-05-17 14:22:46, Jaegeuk Kim wrote:
> Hi Jan,
>
> On 05/02, Jan Kara wrote:
> > Commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as
> > synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
> > definitions. generic_make_request_checks() however strips REQ_FUA and
> > REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
> > write cache and thus write effectively becomes asynchronous which can
> > lead to performance regressions.
> >
> > Fix the problem by making sure all bios which are synchronous are
> > properly marked with REQ_SYNC.
> >
> > Fixes: b685d3d65ac791406e0dfd8779cc9b3707fea5a3
>
> Looks good to me. Thank you for the patch.
> BTW, does this need cc to stable?
>
> Cc: stable@xxxxxxxxxxxxxxx # 4.9+
Yeah, good point. Added.
Honza
>
> Thanks,
>
> > CC: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > CC: linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > ---
> > fs/f2fs/data.c | 2 +-
> > fs/f2fs/segment.c | 2 +-
> > fs/f2fs/super.c | 2 +-
> > 3 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 1602b4bccae6..dd24476e8d2c 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -309,7 +309,7 @@ static void __f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
> > if (type >= META_FLUSH) {
> > io->fio.type = META_FLUSH;
> > io->fio.op = REQ_OP_WRITE;
> > - io->fio.op_flags = REQ_META | REQ_PRIO;
> > + io->fio.op_flags = REQ_META | REQ_PRIO | REQ_SYNC;
> > if (!test_opt(sbi, NOBARRIER))
> > io->fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
> > }
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 29ef7088c558..0c24cec55dc9 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -416,7 +416,7 @@ static int __submit_flush_wait(struct block_device *bdev)
> > struct bio *bio = f2fs_bio_alloc(0);
> > int ret;
> >
> > - bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
> > + bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
> > bio->bi_bdev = bdev;
> > ret = submit_bio_wait(bio);
> > bio_put(bio);
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 96fe8ed73100..fa5af1f04798 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -1307,7 +1307,7 @@ static int __f2fs_commit_super(struct buffer_head *bh,
> > unlock_buffer(bh);
> >
> > /* it's rare case, we can do fua all the time */
> > - return __sync_dirty_buffer(bh, REQ_PREFLUSH | REQ_FUA);
> > + return __sync_dirty_buffer(bh, REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
> > }
> >
> > static inline bool sanity_check_area_boundary(struct f2fs_sb_info *sbi,
> > --
> > 2.12.0
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
