Re: [md PATCH 01/18] md: disconnect device from personality before trying to remove it.

Shaohua Li
2016-06-03T22:31:30Z

On Thu, Jun 02, 2016 at 04:19:52PM +1000, Neil Brown wrote:
> When the HOT_REMOVE_DISK ioctl is used to remove a device, we
> call remove_and_add_spares() which will remove it from the personality
> if possible. This improves the chances that the removal will succeed.
>
> When writing "remove" to dev-XX/state, we don't. So that can fail more easily.
>
> So add the remove_and_add_spares() into "remove" handling.
>
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
> drivers/md/md.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 866825f10b4c..2d26099e1160 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -2596,6 +2596,8 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
> else
> err = -EBUSY;
> } else if (cmd_match(buf, "remove")) {
> + clear_bit(Blocked, &rdev->flags);
> + remove_and_add_spares(rdev->mddev, rdev);
> if (rdev->raid_disk >= 0)
> err = -EBUSY;
> else {

Do we need wakeup rdev->blocked_wait here? I noticed some times we do the
wakeup but sometimes we not. This makes me worry about
md_wait_for_blocked_rdev. Will timeout cause anything bad?

Thanks,
Shaohua