From 48c2993c59363628a7a2eee642bed42ad719032a Mon Sep 17 00:00:00 2001
From: anserper <anserper>
Date: Mon, 11 Aug 2008 21:52:00 +0000
Subject: [PATCH] Branch HEAD b=16536 i=andrew.perepechko@sun.com (panda)
i=oleg.drokin@sun.com (green) fix a possible oops when a cancelling lock is
referenced with a 'fast lock' routine
---
lustre/ldlm/ldlm_lock.c | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/lustre/ldlm/ldlm_lock.c b/lustre/ldlm/ldlm_lock.c
index c1f12a7e80..31103ebcb7 100644
--- a/lustre/ldlm/ldlm_lock.c
+++ b/lustre/ldlm/ldlm_lock.c
@@ -959,15 +959,34 @@ int ldlm_lock_fast_match(struct ldlm_lock *lock, int rw,
void **cookie)
{
LASSERT(rw == OBD_BRW_READ || rw == OBD_BRW_WRITE);
- /* should LCK_GROUP be handled in a special way? */
- if (lock && (rw == OBD_BRW_READ ||
- (lock->l_granted_mode & (LCK_PW | LCK_GROUP))) &&
- (lock->l_policy_data.l_extent.start <= start) &&
- (lock->l_policy_data.l_extent.end >= end)) {
- ldlm_lock_addref_internal(lock, rw == OBD_BRW_WRITE ? LCK_PW : LCK_PR);
- *cookie = (void *)lock;
- return 1; /* avoid using rc for stack relief */
- }
+
+ if (!lock)
+ return 0;
+
+ lock_res_and_lock(lock);
+ /* check if granted mode is compatible */
+ if (rw == OBD_BRW_WRITE &&
+ !(lock->l_granted_mode & (LCK_PW|LCK_GROUP)))
+ goto no_match;
+
+ /* does the lock cover the region we would like to access? */
+ if ((lock->l_policy_data.l_extent.start > start) ||
+ (lock->l_policy_data.l_extent.end < end))
+ goto no_match;
+
+ /* if we received a blocking callback and the lock is no longer
+ * referenced, don't use it */
+ if ((lock->l_flags & LDLM_FL_CBPENDING) &&
+ !lock->l_writers && !lock->l_readers)
+ goto no_match;
+
+ ldlm_lock_addref_internal_nolock(lock, rw == OBD_BRW_WRITE ? LCK_PW : LCK_PR);
+ unlock_res_and_lock(lock);
+ *cookie = (void *)lock;
+ return 1; /* avoid using rc for stack relief */
+
+no_match:
+ unlock_res_and_lock(lock);
return 0;
}
--
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