Commit 4e064062 authored May 20, 2019 by Andrea Parri Committed by Greg Kroah-Hartman Aug 06, 2019

ceph: fix improper use of smp_mb__before_atomic()



[ 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: fdd4e158 ("ceph: rework dcache readdir")
Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 44f7521a

fs/ceph/super.h

+6 −1

Original line number	Diff line number	Diff line
		@@ -476,7 +476,12 @@ 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);
		}