On Thu, Dec 21, 2023 at 5:17 PM Li Nan <linan666@xxxxxxxxxxxxxxx> wrote:
>
>
>
> 在 2023/12/22 2:58, Song Liu 写道:
[...]
> > In general, I would like to avoid adding flags if possible.
> >
>
> This flag is mainly used to fix deadlock in next patch. Or should we
> export bd_find_holder_disk()? Link hodler if it return NULL.
> just like:
>
> rdev_for_each_rcu
> if (!bd_find_holder_disk)
> bd_link_disk_holder
I was thinking we will not need the flag if we fail bind_rdev_to_array()
on error (below).
>
>
> >> };
> >>
> >> static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
> >> diff --git a/drivers/md/md.c b/drivers/md/md.c
> >> index e05858653a41..d6612b922c76 100644
> >> --- a/drivers/md/md.c
> >> +++ b/drivers/md/md.c
> >> @@ -2526,7 +2526,8 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
> >> sysfs_get_dirent_safe(rdev->kobj.sd, "bad_blocks");
> >>
> >> list_add_rcu(&rdev->same_set, &mddev->disks);
> >> - bd_link_disk_holder(rdev->bdev, mddev->gendisk);
> >> + if (!bd_link_disk_holder(rdev->bdev, mddev->gendisk))
> >> + set_bit(SymlinkCreated, &rdev->flags);
> >
> > Shall we just fail bind_rdev_to_array() if bd_link_disk_holder()
> > returns non-zero?
> >
>
> I keep this action because of commit 00bcb4ac7ee7 ("md: reduce
> dependence on sysfs."). Fail bind_rdev_to_array is good to me.
I wonder whether the assumption in 00bcb4ac7ee7 is still true. If
bd_link_disk_holder() fails for valid reasons, we need to handle it
properly (set a flag, check the flag on unlink, etc.). If we only fail
bd_link_disk_holder() on extreme cases (ENOMEM, etc.), we can
just fail bind_rdev_to_array().
Thanks,
Song
