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Message-Id: <20190726133936.11177-33-sashal@kernel.org>
Date: Fri, 26 Jul 2019 09:38:43 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Andrea Parri <andrea.parri@...rulasolutions.com>,
"Paul E. McKenney" <paulmck@...ux.ibm.com>,
Peter Zijlstra <peterz@...radead.org>,
"Yan, Zheng" <zyan@...hat.com>, Ilya Dryomov <idryomov@...il.com>,
Sasha Levin <sashal@...nel.org>, ceph-devel@...r.kernel.org
Subject: [PATCH AUTOSEL 5.2 33/85] ceph: fix improper use of smp_mb__before_atomic()
From: Andrea Parri <andrea.parri@...rulasolutions.com>
[ 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" <paulmck@...ux.ibm.com>
Reported-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Andrea Parri <andrea.parri@...rulasolutions.com>
Reviewed-by: "Yan, Zheng" <zyan@...hat.com>
Signed-off-by: Ilya Dryomov <idryomov@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
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 5f27e1f7f2d6..172ce582b995 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -544,7 +544,12 @@ 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
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