From: Bobi Jam <bobijam.xu@intel.com>
Date: Mon, 14 Mar 2016 02:53:39 +0000 (+0800)
Subject: LU-9229 osc: osc page lru list race
X-Git-Tag: 2.9.59~53
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=refs%2Fchanges%2F86%2F26086%2F4;p=fs%2Flustre-release.git

LU-9229 osc: osc page lru list race

In osc_lru_use() the osc page's ops_lru access is not protected, which
could race with osc_lru_del() and ensuing that
client_obd::cl_lru_in_list counter decreased twice for a single page.

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: I41179112693f77113fdf43d3f859bf778d7bbc44
Reviewed-on: https://review.whamcloud.com/26086
Tested-by: Jenkins
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/osc/osc_page.c b/lustre/osc/osc_page.c
index c1650b8..50d8ecd 100644
--- a/lustre/osc/osc_page.c
+++ b/lustre/osc/osc_page.c
@@ -482,17 +482,19 @@ static void osc_lru_del(struct client_obd *cli, struct osc_page *opg)
 }
 
 /**
- * Delete page from LRUlist for redirty.
+ * Delete page from LRU list for redirty.
  */
 static void osc_lru_use(struct client_obd *cli, struct osc_page *opg)
 {
 	/* If page is being transferred for the first time,
 	 * ops_lru should be empty */
-	if (opg->ops_in_lru && !list_empty(&opg->ops_lru)) {
+	if (opg->ops_in_lru) {
 		spin_lock(&cli->cl_lru_list_lock);
-		__osc_lru_del(cli, opg);
+		if (!list_empty(&opg->ops_lru)) {
+			__osc_lru_del(cli, opg);
+			atomic_long_inc(&cli->cl_lru_busy);
+		}
 		spin_unlock(&cli->cl_lru_list_lock);
-		atomic_long_inc(&cli->cl_lru_busy);
 	}
 }