From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.14 13/37] ceph: fix improper use of smp_mb__before_atomic() Date: Fri, 26 Jul 2019 09:43:08 -0400 Message-ID: <20190726134332.12626-13-sashal@kernel.org> References: <20190726134332.12626-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190726134332.12626-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrea Parri , "Paul E. McKenney" , Peter Zijlstra , "Yan, Zheng" , Ilya Dryomov , Sasha Levin , ceph-devel@vger.kernel.org List-Id: ceph-devel.vger.kernel.org From: Andrea Parri [ Upstream commit 749607731e26dfb2558118038c40e9c0c80d23b5 ] This barrier only applies to the read-modify-write operations; in particular, it does not apply to the atomic64_set() primitive. Replace the barrier with an smp_mb(). Fixes: fdd4e15838e59 ("ceph: rework dcache readdir") Reported-by: "Paul E. McKenney" Reported-by: Peter Zijlstra Signed-off-by: Andrea Parri Reviewed-by: "Yan, Zheng" Signed-off-by: Ilya Dryomov Signed-off-by: Sasha Levin --- fs/ceph/super.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 3e27a28aa44a..60b70f0985f6 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -517,7 +517,12 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci, long long release_count, long long ordered_count) { - smp_mb__before_atomic(); + /* + * Makes sure operations that setup readdir cache (update page + * cache and i_size) are strongly ordered w.r.t. the following + * atomic64_set() operations. + */ + smp_mb(); atomic64_set(&ci->i_complete_seq[0], release_count); atomic64_set(&ci->i_complete_seq[1], ordered_count); } -- 2.20.1