From: Oleg Drokin <green@linuxhacker.ru>
Date: Wed, 5 May 2010 23:35:58 +0000 (-0400)
Subject: b=22522 do not remove from res_list without locks
X-Git-Tag: 1.10.0.42~15
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=33b43d1fea4ef3b603ab6952b6965171e948ef73

b=22522 do not remove from res_list without locks

Patch in bug 21501 moved list manipulation of res_list outside or res_lock
introducing a race window in flock code. Move it back under the lock.

i=rread
i=adilger
---

diff --git a/lustre/ldlm/ldlm_flock.c b/lustre/ldlm/ldlm_flock.c
index 914ed4e..8e17167 100644
--- a/lustre/ldlm/ldlm_flock.c
+++ b/lustre/ldlm/ldlm_flock.c
@@ -605,10 +605,10 @@ granted:
         cfs_list_del_init(&lock->l_flock_waitq);
         cfs_spin_unlock(&ldlm_flock_waitq_lock);
 
+        lock_res_and_lock(lock);
         /* ldlm_lock_enqueue() has already placed lock on the granted list. */
         cfs_list_del_init(&lock->l_res_link);
 
-        lock_res_and_lock(lock);
         if (flags & LDLM_FL_TEST_LOCK) {
                 /* fcntl(F_GETLK) request */
                 /* The old mode was saved in getlk->fl_type so that if the mode