ceph: hold i_ceph_lock when removing caps for freeing inode

ceph_d_revalidate(, LOOKUP_RCU) may call __ceph_caps_issued_mask()
on a freeing inode.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 0176241eaea7..7754d7679122 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1263,20 +1263,22 @@ static int send_cap_msg(struct cap_msg_args *arg)
 }
 
 /*
- * Queue cap releases when an inode is dropped from our cache.  Since
- * inode is about to be destroyed, there is no need for i_ceph_lock.
+ * Queue cap releases when an inode is dropped from our cache.
  */
-void __ceph_remove_caps(struct inode *inode)
+void __ceph_remove_caps(struct ceph_inode_info *ci)
 {
-        struct ceph_inode_info *ci = ceph_inode(inode);
         struct rb_node *p;
 
+        /* lock i_ceph_lock, because ceph_d_revalidate(..., LOOKUP_RCU)
+         * may call __ceph_caps_issued_mask() on a freeing inode. */
+        spin_lock(&ci->i_ceph_lock);
         p = rb_first(&ci->i_caps);
         while (p) {
                 struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
                 p = rb_next(p);
                 __ceph_remove_cap(cap, true);
         }
+        spin_unlock(&ci->i_ceph_lock);
 }
 
 /*