Messages in this thread Patch in this message | | | Date | Tue, 24 Aug 2010 15:44:22 -0700 | From | Greg KH <> | Subject | [017/114] ocfs2/dlm: remove potential deadlock -V3 |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Wengang Wang <wen.gang.wang@oracle.com>
commit b11f1f1ab73fd358b1b734a9427744802202ba68 upstream.
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> Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/ocfs2/dlm/dlmmaster.c | 4 ---- 1 file changed, 4 deletions(-)
--- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -511,8 +511,6 @@ static void dlm_lockres_release(struct k 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_ res->migration_pending = 0; res->inflight_locks = 0; - /* put in dlm_lockres_release */ - dlm_grab(dlm); res->dlm = dlm; kref_init(&res->refs);
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