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authorGuoqing Jiang <gqjiang@suse.com>2016-05-02 18:33:12 +0300
committerShaohua Li <shli@fb.com>2016-05-04 22:39:35 +0300
commit1535212c542285e430d44a75bfc0a99df610f598 (patch)
tree5d387e9c80a353fc7fc28656ecc24243c0b51b1a /drivers/md
parent5b0fb33e8aa1c8a94f763d1025445146412ca766 (diff)
downloadlinux-1535212c542285e430d44a75bfc0a99df610f598.tar.xz
md-cluster: fix locking when node joins cluster during message broadcast
If a node joins the cluster while a message broadcast is under way, a lock issue could happen as follows. For a cluster which included two nodes, if node A is calling __sendmsg before up-convert CR to EX on ack, and node B released CR on ack. But if a new node C joins the cluster and it doesn't receive the message which A sent before, so it could hold CR on ack before A up-convert CR to EX on ack. So a node joining the cluster should get an EX lock on the "token" first to ensure no broadcast is ongoing, then release it after held CR on ack. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/md-cluster.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 76f88f731aa1..30f1160142c1 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -781,17 +781,24 @@ static int join(struct mddev *mddev, int nodes)
cinfo->token_lockres = lockres_init(mddev, "token", NULL, 0);
if (!cinfo->token_lockres)
goto err;
- cinfo->ack_lockres = lockres_init(mddev, "ack", ack_bast, 0);
- if (!cinfo->ack_lockres)
- goto err;
cinfo->no_new_dev_lockres = lockres_init(mddev, "no-new-dev", NULL, 0);
if (!cinfo->no_new_dev_lockres)
goto err;
+ ret = dlm_lock_sync(cinfo->token_lockres, DLM_LOCK_EX);
+ if (ret) {
+ ret = -EAGAIN;
+ pr_err("md-cluster: can't join cluster to avoid lock issue\n");
+ goto err;
+ }
+ cinfo->ack_lockres = lockres_init(mddev, "ack", ack_bast, 0);
+ if (!cinfo->ack_lockres)
+ goto err;
/* get sync CR lock on ACK. */
if (dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR))
pr_err("md-cluster: failed to get a sync CR lock on ACK!(%d)\n",
ret);
+ dlm_unlock_sync(cinfo->token_lockres);
/* get sync CR lock on no-new-dev. */
if (dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR))
pr_err("md-cluster: failed to get a sync CR lock on no-new-dev!(%d)\n", ret);