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authorSrinivas Eeda <srinivas.eeda@oracle.com>2010-03-22 16:50:47 -0700
committerJoel Becker <joel.becker@oracle.com>2010-03-23 18:22:59 -0700
commit14741472a05245ed5778aa0aec055e1f920b6ef8 (patch)
tree0384fc0f8c3439a4bb2900bc725dae8a1f7924dd
parentb54c2ca475fa7d7450a45b6d778dae9dbe0bcbfe (diff)
downloadvexpress-lsk-14741472a05245ed5778aa0aec055e1f920b6ef8.tar.gz
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 <srinivas.eeda@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
-rw-r--r--fs/ocfs2/dlm/dlmmaster.c4
1 files changed, 1 insertions, 3 deletions
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;