[PATCH] ceph: init the i_list/g_list for cap flush

[xiubli@redhat.com]

From: Xiubo Li <xiubli@redhat.com>

Always init the i_list/g_list in the begining to make sure it won't
crash the kernel if someone want to delete the cap_flush from the
lists.

Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/52401
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/caps.c | 2 +-
 fs/ceph/snap.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 4f0dbc640b0b..60f60260cf42 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3666,7 +3666,7 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
 	while (!list_empty(&to_remove)) {
 		cf = list_first_entry(&to_remove,
 				      struct ceph_cap_flush, i_list);
-		list_del(&cf->i_list);
+		list_del_init(&cf->i_list);
 		if (!cf->is_capsnap)
 			ceph_free_cap_flush(cf);
 	}
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 62fab59bbf96..b41e6724c591 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -488,6 +488,8 @@ static void ceph_queue_cap_snap(struct ceph_inode_info *ci)
 		return;
 	}
 	capsnap->cap_flush.is_capsnap = true;
+	INIT_LIST_HEAD(&capsnap->cap_flush.i_list);
+	INIT_LIST_HEAD(&capsnap->cap_flush.g_list);
 
 	spin_lock(&ci->i_ceph_lock);
 	used = __ceph_caps_used(ci);
-- 
2.27.0