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| author |   Joseph Qi <joseph.qi@huawei.com> | 2015-09-22 14:59:20 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-22 15:09:53 -0700 |
| commit | 012572d4fc2e4ddd5c8ec8614d51414ec6cae02a (patch) | |
| tree | ce5b9dc95ea8f3e9ea4a84d6b87cce8d0777e94b /fs/ocfs2/dlm/dlmmaster.c | |
| parent | membarrier: clean up selftest (diff) | |
| download | linux-dev-012572d4fc2e4ddd5c8ec8614d51414ec6cae02a.tar.xz linux-dev-012572d4fc2e4ddd5c8ec8614d51414ec6cae02a.zip | |
ocfs2/dlm: fix deadlock when dispatch assert master
The order of the following three spinlocks should be:
dlm_domain_lock < dlm_ctxt->spinlock < dlm_lock_resource->spinlock
But dlm_dispatch_assert_master() is called while holding
dlm_ctxt->spinlock and dlm_lock_resource->spinlock, and then it calls
dlm_grab() which will take dlm_domain_lock.
Once another thread (for example, dlm_query_join_handler) has already
taken dlm_domain_lock, and tries to take dlm_ctxt->spinlock deadlock
happens.
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: "Junxiao Bi" <junxiao.bi@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | fs/ocfs2/dlm/dlmmaster.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index 46b8b2bbc95a..ee5aa4daaea0 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -1439,6 +1439,7 @@ int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data, int found, ret; int set_maybe; int dispatch_assert = 0; + int dispatched = 0; if (!dlm_grab(dlm)) return DLM_MASTER_RESP_NO; @@ -1658,15 +1659,18 @@ send_response: mlog(ML_ERROR, "failed to dispatch assert master work\n"); response = DLM_MASTER_RESP_ERROR; dlm_lockres_put(res); - } else + } else { + dispatched = 1; __dlm_lockres_grab_inflight_worker(dlm, res); + } spin_unlock(&res->spinlock); } else { if (res) dlm_lockres_put(res); } - dlm_put(dlm); + if (!dispatched) + dlm_put(dlm); return response; } @@ -2090,7 +2094,6 @@ int dlm_dispatch_assert_master(struct dlm_ctxt *dlm, /* queue up work for dlm_assert_master_worker */ - dlm_grab(dlm); /* get an extra ref for the work item */ dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL); item->u.am.lockres = res; /* already have a ref */ /* can optionally ignore node numbers higher than this node */ |