From e19508fa4df896b115f5321c21ce7669559b0863 Mon Sep 17 00:00:00 2001 From: Guoqing Jiang Date: Mon, 21 Dec 2015 10:51:01 +1100 Subject: [PATCH] md-cluster: update comments for MD_CLUSTER_SEND_LOCKED_ALREADY 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 Signed-off-by: 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 ad3ec7df1547..0ded8e97751d 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); } -- 2.45.2