From 378f7b85e60304fb40cd878c40b85ca9b1e3e533 Mon Sep 17 00:00:00 2001
From: shadow <shadow>
Date: Mon, 19 Jan 2009 21:21:30 +0000
Subject: [PATCH] release lock refernce only after add page to pages list.

Branch b_release_1_8_0
b=17972
i=shadow
i=johann
---
 lustre/ChangeLog   | 7 +++++++
 lustre/osc/cache.c | 7 +++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/lustre/ChangeLog b/lustre/ChangeLog
index a1735f5..4fad746 100644
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -44,6 +44,13 @@
 	  information, please refer to bugzilla 17630.
 
 Severity   : normal
+Frequency  : rarw
+Bugzilla   : 17972
+Descriptoin: stuck in cache_remove_extent() or panic with accessing to already
+             freed look.
+Details    : release lock refernce only after add page to pages list.
+
+Severity   : normal
 Frequency  : start MDS on uncleanly shutdowned MDS device
 Bugzilla   : 16839
 Descriptoin: ll_sync thread stay in waiting mds<>ost recovery finished
diff --git a/lustre/osc/cache.c b/lustre/osc/cache.c
index 1f7f64f..f0a8bce 100644
--- a/lustre/osc/cache.c
+++ b/lustre/osc/cache.c
@@ -86,6 +86,7 @@ int cache_add_extent(struct lustre_cache *cache, struct ldlm_res_id *res,
         struct lustre_handle tmplockh;
         ldlm_policy_data_t tmpex;
         struct ldlm_lock *lock = NULL;
+        int mode = 0;
         ENTRY;
 
         /* Don't add anything second time */
@@ -108,7 +109,6 @@ int cache_add_extent(struct lustre_cache *cache, struct ldlm_res_id *res,
                          lock->l_policy_data.l_extent.start,
                          lock->l_policy_data.l_extent.end, extent->oap_obj_off);
         } else {
-                int mode;
                 /* Real extent width calculation here once we have real
                  * extents
                  */
@@ -138,13 +138,16 @@ int cache_add_extent(struct lustre_cache *cache, struct ldlm_res_id *res,
                                "under us\n");
                         RETURN(-ENOLCK);
                 }
-                ldlm_lock_decref(&tmplockh, mode);
         }
 
         spin_lock(&lock->l_extents_list_lock);
         list_add_tail(&extent->oap_page_list, &lock->l_extents_list);
         spin_unlock(&lock->l_extents_list_lock);
         extent->oap_ldlm_lock = lock;
+        LASSERTF(!(lock->l_flags & LDLM_FL_CANCEL), "Adding a page to already "
+                 "cancelled lock %p", lock);
+        if (mode)
+                ldlm_lock_decref(&tmplockh, mode);
         LDLM_LOCK_PUT(lock);
 
         RETURN(0);
-- 
1.8.3.1