On Sat, Dec 05 2015, Guoqing Jiang wrote:
> 1. fix unbalanced parentheses.
> 2. add more description about that MD_CLUSTER_SEND_LOCKED_ALREADY
> will be cleared after set it in add_new_disk.
>
> Signed-off-by: Guoqing Jiang <gqjiang@xxxxxxxx>
Applied, thanks.
NeilBrown
> ---
> drivers/md/md-cluster.c | 23 ++++++++++++++++++-----
> 1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
> index ad3ec7d..0ded8e9 100644
> --- a/drivers/md/md-cluster.c
> +++ b/drivers/md/md-cluster.c
> @@ -53,11 +53,12 @@ struct resync_info {
> * accomodate lock and hold. See next comment.
> */
> #define MD_CLUSTER_SEND_LOCK 4
> -/* If cluster operations must lock the communication channel,
> - * so as to perform extra operations (and no other operation
> - * is allowed on the MD, such as adding a disk. Token needs
> - * to be locked and held until the operation completes with
> - * a md_update_sb(), which would eventually release the lock.
> +/* If cluster operations (such as adding a disk) must lock the
> + * communication channel, so as to perform extra operations
> + * (update metadata) and no other operation is allowed on the
> + * MD. Token needs to be locked and held until the operation
> + * completes witha md_update_sb(), which would eventually release
> + * the lock.
> */
> #define MD_CLUSTER_SEND_LOCKED_ALREADY 5
>
> @@ -1021,6 +1022,18 @@ static int add_new_disk(struct mddev *mddev, struct md_rdev *rdev)
> unlock_comm(cinfo);
> else {
> dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
> + /* Since MD_CHANGE_DEVS will be set in add_bound_rdev which
> + * will run soon after add_new_disk, the below path will be
> + * invoked:
> + * md_wakeup_thread(mddev->thread)
> + * -> conf->thread (raid1d)
> + * -> md_check_recovery -> md_update_sb
> + * -> metadata_update_start/finish
> + * MD_CLUSTER_SEND_LOCKED_ALREADY will be cleared eventually.
> + *
> + * For other failure cases, metadata_update_cancel and
> + * add_new_disk_cancel also clear below bit as well.
> + * */
> set_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
> wake_up(&cinfo->wait);
> }
> --
> 2.1.4
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