From 14741472a05245ed5778aa0aec055e1f920b6ef8 Mon Sep 17 00:00:00 2001 From: Srinivas Eeda Date: Mon, 22 Mar 2010 16:50:47 -0700 Subject: ocfs2: Fix a race in o2dlm lockres mastery In o2dlm, the master of a lock resource keeps a map of all interested nodes. This prevents the master from purging the resource before an interested node can create a lock. A race between the mastery thread and the mastery handler allowed an interested node to discover who the master is without informing the master directly. This is easily fixed by holding the dlm spinlock a little longer in the mastery handler. Signed-off-by: Srinivas Eeda Signed-off-by: Joel Becker --- fs/ocfs2/dlm/dlmmaster.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'fs/ocfs2') diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index a659606dcb9..9289b4357d2 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -1875,7 +1875,6 @@ int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data, ok: spin_unlock(&res->spinlock); } - spin_unlock(&dlm->spinlock); // mlog(0, "woo! got an assert_master from node %u!\n", // assert->node_idx); @@ -1926,7 +1925,6 @@ ok: /* master is known, detach if not already detached. * ensures that only one assert_master call will happen * on this mle. */ - spin_lock(&dlm->spinlock); spin_lock(&dlm->master_lock); rr = atomic_read(&mle->mle_refs.refcount); @@ -1959,7 +1957,6 @@ ok: __dlm_put_mle(mle); } spin_unlock(&dlm->master_lock); - spin_unlock(&dlm->spinlock); } else if (res) { if (res->owner != assert->node_idx) { mlog(0, "assert_master from %u, but current " @@ -1967,6 +1964,7 @@ ok: res->owner, namelen, name); } } + spin_unlock(&dlm->spinlock); done: ret = 0; -- cgit v1.2.3