From: Bruno Faccini <bruno.faccini@intel.com>
Date: Wed, 30 Aug 2017 09:37:03 +0000 (+0200)
Subject: LU-9930 llite: only clear lli_sai if the setter
X-Git-Tag: 2.10.54~38
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=f4a0ebe28e88cbdd79061fad275cb9494fdba225;p=fs%2Flustre-release.git

LU-9930 llite: only clear lli_sai if the setter

Previous to this patch, start_statahead_thread() was
unconditionnally clearing lli->lli_sai upon error, leading
to crash upon racy scenario where it has just been set in/by
another thread context.
Now, only clear lli_sai if current thread has set it.

Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>
Change-Id: I555febfad3494c9dd90eeb72d6dd9157428179ea
Reviewed-on: https://review.whamcloud.com/28794
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/llite/statahead.c b/lustre/llite/statahead.c
index 3430f81..44cc9e6 100644
--- a/lustre/llite/statahead.c
+++ b/lustre/llite/statahead.c
@@ -1608,8 +1608,10 @@ out:
 	/* once we start statahead thread failed, disable statahead so that
 	 * subsequent stat won't waste time to try it. */
 	spin_lock(&lli->lli_sa_lock);
-	lli->lli_sa_enabled = 0;
-	lli->lli_sai = NULL;
+	if (sai != NULL && lli->lli_sai == sai) {
+		lli->lli_sa_enabled = 0;
+		lli->lli_sai = NULL;
+	}
 	spin_unlock(&lli->lli_sa_lock);
 
 	if (sai != NULL)