fs: dlm: fix mismatch of plock results from userspace
When a waiting plock request (F_SETLKW) is sent to userspace
for processing (dlm_controld), the result is returned at a
later time. That result could be incorrectly matched to a
different waiting request in cases where the owner field is
the same (e.g. different threads in a process.) This is fixed
by comparing all the properties in the request and reply.
The results for non-waiting plock requests are now matched
based on list order because the results are returned in the
same order they were sent.
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
index c9e1d5f..70a4752e 100644
--- a/fs/dlm/plock.c
+++ b/fs/dlm/plock.c
@@ -395,7 +395,7 @@ static ssize_t dev_read(struct file *file, char __user *u, size_t count,
if (op->info.flags & DLM_PLOCK_FL_CLOSE)
list_del(&op->list);
else
- list_move(&op->list, &recv_list);
+ list_move_tail(&op->list, &recv_list);
memcpy(&info, &op->info, sizeof(info));
}
spin_unlock(&ops_lock);
@@ -433,20 +433,52 @@ static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
if (check_version(&info))
return -EINVAL;
+ /*
+ * The results for waiting ops (SETLKW) can be returned in any
+ * order, so match all fields to find the op. The results for
+ * non-waiting ops are returned in the order that they were sent
+ * to userspace, so match the result with the first non-waiting op.
+ */
spin_lock(&ops_lock);
- list_for_each_entry(iter, &recv_list, list) {
- if (iter->info.fsid == info.fsid &&
- iter->info.number == info.number &&
- iter->info.owner == info.owner) {
- list_del_init(&iter->list);
- memcpy(&iter->info, &info, sizeof(info));
- if (iter->data)
- do_callback = 1;
- else
- iter->done = 1;
- op = iter;
- break;
+ if (info.wait) {
+ list_for_each_entry(iter, &recv_list, list) {
+ if (iter->info.fsid == info.fsid &&
+ iter->info.number == info.number &&
+ iter->info.owner == info.owner &&
+ iter->info.pid == info.pid &&
+ iter->info.start == info.start &&
+ iter->info.end == info.end &&
+ iter->info.ex == info.ex &&
+ iter->info.wait) {
+ op = iter;
+ break;
+ }
}
+ } else {
+ list_for_each_entry(iter, &recv_list, list) {
+ if (!iter->info.wait) {
+ op = iter;
+ break;
+ }
+ }
+ }
+
+ if (op) {
+ /* Sanity check that op and info match. */
+ if (info.wait)
+ WARN_ON(op->info.optype != DLM_PLOCK_OP_LOCK);
+ else
+ WARN_ON(op->info.fsid != info.fsid ||
+ op->info.number != info.number ||
+ op->info.owner != info.owner ||
+ op->info.optype != info.optype);
+
+ list_del_init(&op->list);
+ memcpy(&op->info, &info, sizeof(info));
+ if (op->data)
+ do_callback = 1;
+ else
+ op->done = 1;
}
spin_unlock(&ops_lock);
