ocfs2:dlm: avoid dlm->ast_lock lockres->spinlock dependency break
Currently we process a dirty lockres with the lockres->spinlock taken. While
during the process, we may need to lock on dlm->ast_lock. This breaks the
dependency of dlm->ast_lock(lock first) and lockres->spinlock(lock second).
This patch fixes the problem.
Since we can't release lockres->spinlock, we have to take dlm->ast_lock
just before taking the lockres->spinlock and release it after lockres->spinlock
is released. And use __dlm_queue_bast()/__dlm_queue_ast(), the nolock version,
in dlm_shuffle_lists(). There are no too many locks on a lockres, so there is no
performance harm.
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
diff --git a/fs/ocfs2/dlm/dlmast.c b/fs/ocfs2/dlm/dlmast.c
index 390a887..7ec61d9 100644
--- a/fs/ocfs2/dlm/dlmast.c
+++ b/fs/ocfs2/dlm/dlmast.c
@@ -89,7 +89,7 @@
return 0;
}
-static void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
mlog_entry_void();
@@ -146,7 +146,7 @@
}
-static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
+void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
mlog_entry_void();
diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 4011568..4b6ae2c 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -904,6 +904,8 @@
void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
+void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
+void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
void dlm_do_local_ast(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
struct dlm_lock *lock);
diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 52ec020..0bdd28e 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -310,6 +310,7 @@
* spinlock, and because we know that it is not migrating/
* recovering/in-progress, it is fine to reserve asts and
* basts right before queueing them all throughout */
+ assert_spin_locked(&dlm->ast_lock);
assert_spin_locked(&res->spinlock);
BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
DLM_LOCK_RES_RECOVERING|
@@ -338,7 +339,7 @@
/* queue the BAST if not already */
if (lock->ml.highest_blocked == LKM_IVMODE) {
__dlm_lockres_reserve_ast(res);
- dlm_queue_bast(dlm, lock);
+ __dlm_queue_bast(dlm, lock);
}
/* update the highest_blocked if needed */
if (lock->ml.highest_blocked < target->ml.convert_type)
@@ -356,7 +357,7 @@
can_grant = 0;
if (lock->ml.highest_blocked == LKM_IVMODE) {
__dlm_lockres_reserve_ast(res);
- dlm_queue_bast(dlm, lock);
+ __dlm_queue_bast(dlm, lock);
}
if (lock->ml.highest_blocked < target->ml.convert_type)
lock->ml.highest_blocked =
@@ -384,7 +385,7 @@
spin_unlock(&target->spinlock);
__dlm_lockres_reserve_ast(res);
- dlm_queue_ast(dlm, target);
+ __dlm_queue_ast(dlm, target);
/* go back and check for more */
goto converting;
}
@@ -403,7 +404,7 @@
can_grant = 0;
if (lock->ml.highest_blocked == LKM_IVMODE) {
__dlm_lockres_reserve_ast(res);
- dlm_queue_bast(dlm, lock);
+ __dlm_queue_bast(dlm, lock);
}
if (lock->ml.highest_blocked < target->ml.type)
lock->ml.highest_blocked = target->ml.type;
@@ -419,7 +420,7 @@
can_grant = 0;
if (lock->ml.highest_blocked == LKM_IVMODE) {
__dlm_lockres_reserve_ast(res);
- dlm_queue_bast(dlm, lock);
+ __dlm_queue_bast(dlm, lock);
}
if (lock->ml.highest_blocked < target->ml.type)
lock->ml.highest_blocked = target->ml.type;
@@ -445,7 +446,7 @@
spin_unlock(&target->spinlock);
__dlm_lockres_reserve_ast(res);
- dlm_queue_ast(dlm, target);
+ __dlm_queue_ast(dlm, target);
/* go back and check for more */
goto converting;
}
@@ -675,6 +676,7 @@
/* lockres can be re-dirtied/re-added to the
* dirty_list in this gap, but that is ok */
+ spin_lock(&dlm->ast_lock);
spin_lock(&res->spinlock);
if (res->owner != dlm->node_num) {
__dlm_print_one_lock_resource(res);
@@ -695,6 +697,7 @@
/* move it to the tail and keep going */
res->state &= ~DLM_LOCK_RES_DIRTY;
spin_unlock(&res->spinlock);
+ spin_unlock(&dlm->ast_lock);
mlog(0, "delaying list shuffling for in-"
"progress lockres %.*s, state=%d\n",
res->lockname.len, res->lockname.name,
@@ -716,6 +719,7 @@
dlm_shuffle_lists(dlm, res);
res->state &= ~DLM_LOCK_RES_DIRTY;
spin_unlock(&res->spinlock);
+ spin_unlock(&dlm->ast_lock);
dlm_lockres_calc_usage(dlm, res);