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| author | Guoqing Jiang <gqjiang@suse.com> | 2016-05-02 11:33:12 -0400 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2016-05-04 12:39:35 -0700 |
| commit | 1535212c542285e430d44a75bfc0a99df610f598 (patch) | |
| tree | 5d387e9c80a353fc7fc28656ecc24243c0b51b1a /drivers/md/md-cluster.c | |
| parent | 5b0fb33e8aa1c8a94f763d1025445146412ca766 (diff) | |
| download | linux-1535212c542285e430d44a75bfc0a99df610f598.tar.gz linux-1535212c542285e430d44a75bfc0a99df610f598.tar.bz2 linux-1535212c542285e430d44a75bfc0a99df610f598.zip | |
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/md-cluster.c')
| -rw-r--r-- | drivers/md/md-cluster.c | 13 |
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); |