Re: [PATCH] blk-core: use pr_warn_ratelimited() in bio_check_ro()

[Yu Kuai]

Hi,

在 2023/11/07 11:50, yebin (H) 写道:
> On 2023/11/7 19:12, Yu Kuai wrote:
> > From: Yu Kuai <yukuai3@xxxxxxxxxx>
> >
> > If one of the underlying disks of raid or dm is set to read-only, then
> > each io will generate new log, which will cause message storm. This
> > environment is indeed problematic, however we can't make sure our
> > naive custormer won't do this, hence use pr_warn_ratelimited() to
> > prevent message storm in this case.
> >
> > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   block/blk-core.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/block/blk-core.c b/block/blk-core.c
> > index 9d51e9894ece..fdf25b8d6e78 100644
> > --- a/block/blk-core.c
> > +++ b/block/blk-core.c
> > @@ -501,8 +501,8 @@ static inline void bio_check_ro(struct bio *bio)
> >       if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
> >           if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
> >               return;
> > -        pr_warn("Trying to write to read-only block-device %pg\n",
> > -            bio->bi_bdev);
> > +        pr_warn_ratelimited("Trying to write to read-only 
> > block-device %pg\n",
> > +                    bio->bi_bdev);
> Acctually, before commit  57e95e4670d1 ("block: fix and cleanup 
> bio_check_ro") , there's only print warning once.
> I wrote a patch earlier, set GD_ROWR_WARNED flag for disk after emit 
> warning. You can look at the patch in the
> attachment, Is it possible to solve your problem.

Yes, this can work, other than that I think the flag should be in
block_device instead of gendisk.

However, I'm not sure which is better for now, hope Christoph or Ming
or anyone can give some advise.

Thanks,
Kuai
> >           /* Older lvm-tools actually trigger this */
> >       }
> >   }