On Thu, 7 Apr 2022 17:16:37 -0700
Song Liu <song@xxxxxxxxxx> wrote:
> On Tue, Mar 22, 2022 at 8:24 AM Mariusz Tkaczyk
> <mariusz.tkaczyk@xxxxxxxxxxxxxxx> wrote:
> >
> > Patch 62f7b1989c0 ("md raid0/linear: Mark array as 'broken' and
> > fail BIOs if a member is gone") allowed to finish writes earlier
> > (before level dependent actions) for non-redundant arrays.
> >
> > To achieve that MD_BROKEN is added to mddev->flags if drive
> > disappearance is detected. This is done in is_mddev_broken() which
> > is confusing and not consistent with other levels where
> > error_handler() is used. This patch adds appropriate error_handler
> > for raid0 and linear and adopt md_error() to the change.
> >
> > Usage of error_handler causes that disk failure can be requested
> > from userspace. User can fail the array via #mdadm --set-faulty
> > command. This is not safe and will be fixed in mdadm. It is
> > correctable because failed state is not recorded in the metadata.
> > After next assembly array will be read-write again. For safety
> > reason is better to keep MD_BROKEN in runtime only.
> >
> > Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@xxxxxxxxxxxxxxx>
>
> Sorry for the late response.
>
> > ---
> > drivers/md/md-linear.c | 14 +++++++++++++-
> > drivers/md/md.c | 6 +++++-
> > drivers/md/md.h | 10 ++--------
> > drivers/md/raid0.c | 14 +++++++++++++-
> > 4 files changed, 33 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
> > index 1ff51647a682..c33cd28f1dba 100644
> > --- a/drivers/md/md-linear.c
> > +++ b/drivers/md/md-linear.c
> > @@ -233,7 +233,8 @@ static bool linear_make_request(struct mddev
> > *mddev, struct bio *bio) bio_sector < start_sector))
> > goto out_of_bounds;
> >
> > - if (unlikely(is_mddev_broken(tmp_dev->rdev, "linear"))) {
> > + if (unlikely(is_rdev_broken(tmp_dev->rdev))) {
> > + md_error(mddev, tmp_dev->rdev);
>
> I apologize if we discussed this before. Shall we just call
> linear_error() here?If we go this way, we don't really need ...
>
> > bio_io_error(bio);
> > return true;
> > }
> > @@ -281,6 +282,16 @@ static void linear_status (struct seq_file
> > *seq, struct mddev *mddev) seq_printf(seq, " %dk rounding",
> > mddev->chunk_sectors / 2); }
> >
> > +static void linear_error(struct mddev *mddev, struct md_rdev *rdev)
> > +{
> > + if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) {
> > + char *md_name = mdname(mddev);
> > +
> > + pr_crit("md/linear%s: Disk failure on %pg detected,
> > failing array.\n",
> > + md_name, rdev->bdev);
> > + }
> > +}
> > +
> > static void linear_quiesce(struct mddev *mddev, int state)
> > {
> > }
> > @@ -297,6 +308,7 @@ static struct md_personality linear_personality
> > = .hot_add_disk = linear_add,
> > .size = linear_size,
> > .quiesce = linear_quiesce,
> > + .error_handler = linear_error,
>
> ... set error_handler here, and ...
>
> > };
> >
> > static int __init linear_init (void)
> > diff --git a/drivers/md/md.c b/drivers/md/md.c
> > index 0a89f072dae0..3354afc9d2a3 100644
> > --- a/drivers/md/md.c
> > +++ b/drivers/md/md.c
> > @@ -7985,7 +7985,11 @@ void md_error(struct mddev *mddev, struct
> > md_rdev *rdev)
> >
> > if (!mddev->pers || !mddev->pers->error_handler)
> > return;
> > - mddev->pers->error_handler(mddev,rdev);
> > + mddev->pers->error_handler(mddev, rdev);
> > +
> > + if (mddev->pers->level == 0 || mddev->pers->level ==
> > LEVEL_LINEAR)
> > + return;
>
> ... this check here.
>
> Did I miss something?
>
Hi Song,
That is correct, we can do the same for raid0. I did it this way to
make it similar to redundant levels.
If you think that it is overhead, I can drop it.
Thanks,
Mariusz
