[4/4] ceph: fix improper use of smp_mb__before_atomic()
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Message ID 1558373038-5611-5-git-send-email-andrea.parri@amarulasolutions.com
State New
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Series
  • Untitled series #119997
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Commit Message

Andrea Parri May 20, 2019, 5:23 p.m. UTC
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(-)

Comments

Yan, Zheng May 21, 2019, 2:18 a.m. UTC | #1
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

Patch
diff mbox series

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);
 }