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ocfs2/dlm: remove potential deadlock -V3

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When we need to take both dlm_domain_lock and dlm->spinlock, we should take
them in order of: dlm_domain_lock then dlm->spinlock.

There is pathes disobey this order. That is calling dlm_lockres_put() with
dlm->spinlock held in dlm_run_purge_list. dlm_lockres_put() calls dlm_put() at
the ref and dlm_put() locks on dlm_domain_lock.

Fix:
Don't grab/put the dlm when the initialising/releasing lockres.
That grab is not required because we don't call dlm_unregister_domain()
based on refcount.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Joel Becker <joel.becker@oracle.com>
This commit is contained in:
Wengang Wang 2010-07-30 23:18:00 +08:00 committed by Joel Becker
parent a524812b7e
commit b11f1f1ab7
1 changed files with 0 additions and 4 deletions
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4
fs/ocfs2/dlm/dlmmaster.c
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@ -511,8 +511,6 @@ static void dlm_lockres_release(struct kref *kref)
atomic_dec(&dlm->res_cur_count);
dlm_put(dlm);
if (!hlist_unhashed(&res->hash_node) ||
!list_empty(&res->granted) ||
!list_empty(&res->converting) ||
@ -585,8 +583,6 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm,
res->migration_pending = 0;
res->inflight_locks = 0;
/* put in dlm_lockres_release */
dlm_grab(dlm);
res->dlm = dlm;
kref_init(&res->refs);