The patch titled
Subject: ocfs2/dlm: fix race between convert and recovery
has been added to the -mm tree. Its filename is
ocfs2-dlm-fix-race-between-convert-and-recovery.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ocfs2-dlm-fix-race-between-convert-and-recovery.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ocfs2-dlm-fix-race-between-convert-and-recovery.patch
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------------------------------------------------------
From: Joseph Qi <joseph.qi@xxxxxxxxxx>
Subject: ocfs2/dlm: fix race between convert and recovery
There is a race window between dlmconvert_remote and
dlm_move_lockres_to_recovery_list, which will cause a lock with
OCFS2_LOCK_BUSY in grant list, thus system hangs.
dlmconvert_remote
{
spin_lock(&res->spinlock);
list_move_tail(&lock->list, &res->converting);
lock->convert_pending = 1;
spin_unlock(&res->spinlock);
status = dlm_send_remote_convert_request();
>>>>>> race window, master has queued ast and return DLM_NORMAL,
and then down before sending ast.
this node detects master down and call
dlm_move_lockres_to_recovery_list, which will revert the
lock to grant list.
Then OCFS2_LOCK_BUSY won't be cleared as new master won't
send ast any more because it thinks already be authorized.
spin_lock(&res->spinlock);
lock->convert_pending = 0;
if (status != DLM_NORMAL)
dlm_revert_pending_convert(res, lock);
spin_unlock(&res->spinlock);
}
In this case, just leave it in convert list and new master will take care
of it after recovery. And if convert request returns other than
DLM_NORMAL, convert thread will do the revert itself. So remove the
revert logic in dlm_move_lockres_to_recovery_list.
Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxx>
Reported-by: Yiwen Jiang <jiangyiwen@xxxxxxxxxx>
Cc: Mark Fasheh <mfasheh@xxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/dlm/dlmrecovery.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff -puN fs/ocfs2/dlm/dlmrecovery.c~ocfs2-dlm-fix-race-between-convert-and-recovery fs/ocfs2/dlm/dlmrecovery.c
--- a/fs/ocfs2/dlm/dlmrecovery.c~ocfs2-dlm-fix-race-between-convert-and-recovery
+++ a/fs/ocfs2/dlm/dlmrecovery.c
@@ -2058,15 +2058,7 @@ void dlm_move_lockres_to_recovery_list(s
queue = dlm_list_idx_to_ptr(res, i);
list_for_each_entry_safe(lock, next, queue, list) {
dlm_lock_get(lock);
- if (lock->convert_pending) {
- /* move converting lock back to granted */
- BUG_ON(i != DLM_CONVERTING_LIST);
- mlog(0, "node died with convert pending "
- "on %.*s. move back to granted list.\n",
- res->lockname.len, res->lockname.name);
- dlm_revert_pending_convert(res, lock);
- lock->convert_pending = 0;
- } else if (lock->lock_pending) {
+ if (lock->lock_pending) {
/* remove pending lock requests completely */
BUG_ON(i != DLM_BLOCKED_LIST);
mlog(0, "node died with lock pending "
_
Patches currently in -mm which might be from joseph.qi@xxxxxxxxxx are
ocfs2-dlm-fix-race-between-convert-and-recovery.patch
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