ceph: don't skip updating wanted caps when cap is stale

[ Upstream commit 0aa971b6fd3f92afef6afe24ef78d9bb14471519 ]

1. try_get_cap_refs() fails to get caps and finds that mds_wanted
   does not include what it wants. It returns -ESTALE.
2. ceph_get_caps() calls ceph_renew_caps(). ceph_renew_caps() finds
   that inode has cap, so it calls ceph_check_caps().
3. ceph_check_caps() finds that issued caps (without checking if it's
   stale) already includes caps wanted by open file, so it skips
   updating wanted caps.

Above events can cause an infinite loop inside ceph_get_caps().

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

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index c3a3ee74e2d840758c470253efd5ae78c96853bb..1b5a50848b5be486ce9ad76b6508b1feb3e8d267 100644 (file)
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1863,8 +1863,12 @@ retry_locked:
                }
 
                /* want more caps from mds? */
-               if (want & ~(cap->mds_wanted | cap->issued))
-                       goto ack;
+               if (want & ~cap->mds_wanted) {
+                       if (want & ~(cap->mds_wanted | cap->issued))
+                               goto ack;
+                       if (!__cap_is_valid(cap))
+                               goto ack;
+               }
 
                /* things we might delay */
                if ((cap->issued & ~retain) == 0 &&