| From | Ben Hutchings <> | Date | Sat, 01 Nov 2014 22:28:03 +0000 | Subject | [PATCH 3.2 073/102] ocfs2/dlm: do not get resource spinlock if lockres is new |
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3.2.64-rc1 review patch. If anyone has any objections, please let me know.
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From: Joseph Qi <joseph.qi@huawei.com>
commit 5760a97c7143c208fa3a8f8cad0ed7dd672ebd28 upstream.
There is a deadlock case which reported by Guozhonghua: https://oss.oracle.com/pipermail/ocfs2-devel/2014-September/010079.html
This case is caused by &res->spinlock and &dlm->master_lock misordering in different threads.
It was introduced by commit 8d400b81cc83 ("ocfs2/dlm: Clean up refmap helpers"). Since lockres is new, it doesn't not require the &res->spinlock. So remove it.
Fixes: 8d400b81cc83 ("ocfs2/dlm: Clean up refmap helpers") Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Reviewed-by: joyce.xue <xuejiufei@huawei.com> Reported-by: Guozhonghua <guozhonghua@h3c.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/ocfs2/dlm/dlmmaster.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
--- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -653,12 +653,9 @@ void dlm_lockres_clear_refmap_bit(struct clear_bit(bit, res->refmap); } - -void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm, +static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { - assert_spin_locked(&res->spinlock); - res->inflight_locks++; mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name, @@ -666,6 +663,13 @@ void dlm_lockres_grab_inflight_ref(struc __builtin_return_address(0)); } +void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm, + struct dlm_lock_resource *res) +{ + assert_spin_locked(&res->spinlock); + __dlm_lockres_grab_inflight_ref(dlm, res); +} + void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) { @@ -855,10 +859,8 @@ lookup: /* finally add the lockres to its hash bucket */ __dlm_insert_lockres(dlm, res); - /* Grab inflight ref to pin the resource */ - spin_lock(&res->spinlock); - dlm_lockres_grab_inflight_ref(dlm, res); - spin_unlock(&res->spinlock); + /* since this lockres is new it doesn't not require the spinlock */ + __dlm_lockres_grab_inflight_ref(dlm, res); /* get an extra ref on the mle in case this is a BLOCK * if so, the creator of the BLOCK may try to put the last
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