/* * * spinlock lock ordering: if multiple locks are needed, obey this ordering: * dlm_domain_lock * struct dlm_ctxt->spinlock * struct dlm_lock_resource->spinlock * struct dlm_ctxt->master_lock * struct dlm_ctxt->ast_lock * dlm_master_list_entry->spinlock * dlm_lock->spinlock * */
There is a violation that locks on dlm_lock_resource->spinlock after locking on dlm_ctxt->ast_lock. The violation is not detected because so far there is only one place where both the two spinlock are taken at the same time. But it is a potential deadlock in future(when the two lock are taken all together in correct order). This patch fixes the problem by changing the calling order. Signed-off-by: Wengang Wang <[email protected]> --- fs/ocfs2/dlm/dlmthread.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c index 2211acf..676ff3e 100644 --- a/fs/ocfs2/dlm/dlmthread.c +++ b/fs/ocfs2/dlm/dlmthread.c @@ -671,8 +671,8 @@ static int dlm_thread(void *data) /* 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); + spin_lock(&dlm->ast_lock); if (res->owner != dlm->node_num) { __dlm_print_one_lock_resource(res); mlog(ML_ERROR, "inprog:%s, mig:%s, reco:%s, dirty:%s\n", @@ -691,8 +691,8 @@ static int dlm_thread(void *data) DLM_LOCK_RES_RECOVERING)) { /* move it to the tail and keep going */ res->state &= ~DLM_LOCK_RES_DIRTY; - spin_unlock(&res->spinlock); spin_unlock(&dlm->ast_lock); + spin_unlock(&res->spinlock); mlog(0, "delaying list shuffling for in-" "progress lockres %.*s, state=%d\n", res->lockname.len, res->lockname.name, @@ -713,8 +713,8 @@ static int dlm_thread(void *data) /* called while holding lockres lock */ dlm_shuffle_lists(dlm, res); res->state &= ~DLM_LOCK_RES_DIRTY; - spin_unlock(&res->spinlock); spin_unlock(&dlm->ast_lock); + spin_unlock(&res->spinlock); dlm_lockres_calc_usage(dlm, res); -- 1.7.2.2 _______________________________________________ Ocfs2-devel mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-devel
