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    SubjectRe: [PATCH 4/4] ceph: fix improper use of smp_mb__before_atomic()
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    On 5/21/19 1:23 AM, Andrea Parri wrote:
    > 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")
    > Cc: stable@vger.kernel.org
    > 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>
    > Cc: "Yan, Zheng" <zyan@redhat.com>
    > Cc: Sage Weil <sage@redhat.com>
    > Cc: Ilya Dryomov <idryomov@gmail.com>
    > Cc: ceph-devel@vger.kernel.org
    > Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>
    > Cc: Peter Zijlstra <peterz@infradead.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 6edab9a750f8a..e02f4ff0be3f1 100644
    > --- a/fs/ceph/super.h
    > +++ b/fs/ceph/super.h
    > @@ -541,7 +541,12 @@ 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);
    > }
    >

    Applied, thanks

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