On 2015/4/22 9:46, Junxiao Bi wrote:
> On 04/21/2015 10:54 AM, alex chen wrote:
>> Hi Junxiao,
>>
>> On 2015/4/16 15:28, Junxiao Bi wrote:
>>> Hi Alex,
>>>
>>> On 03/30/2015 11:22 AM, alex chen wrote:
>>>> If ocfs2 lockres has not been initialized before calling ocfs2_dlm_lock,
>>>> the lock won't be dropped and then will lead umount hung. The case is
>>>> described below:
>>>>
>>>> ocfs2_mknod
>>>> ocfs2_mknod_locked
>>>> __ocfs2_mknod_locked
>>>> ocfs2_journal_access_di
>>>> Failed because of -ENOMEM or other reasons, the inode lockres
>>>> has not been initialized yet.
>>>
>>> If failed here, is OCFS2_I(inode)->ip_inode_lockres initialized? If not
>>
>> The OCFS2_I(inode)->ip_inode_lockres is initialized as follows:
>> __ocfs2_mknod_locked
>> ocfs2_populate_inode
>> ocfs2_inode_lock_res_init
>> ocfs2_lock_res_init_common
>> So if ocfs2_journal_access_di is failed, the ip_inode_lockres will not be
>> initialized.
>> In this situation, we should not allocate a new dlm lockres through calling
>> ocfs2_dlm_lock() in __ocfs2_cluster_lock(), otherwise it will lead umount
>> hung. So we need bread __ocfs2_cluster_lock() if the inode lockres is not
>> be initialized, that is the condition
>> (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED)) is TRUE.
>
> Looks good. Just didn't remind that inode_info is init once when it is
> allocated from "ocfs2_inode_cache". lockres->l_flags is init there.
>
> Thanks,
> Junxiao.
>
Thank you for your remind. If the subject is "check if lockres->l_flags be
initialized to OCFS2_LOCK_INITIALIZED before calling ocfs2_dlm_lock" will
be better.
>>
>>> how can you break __ocfs2_cluster_lock with the following condition?
>>>
>>> if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED))
>>>
>>> Thanks,
>>> Junxiao.
>>>
>>>>
>>>> iput(inode)
>>>> ocfs2_evict_inode
>>>> ocfs2_delete_inode
>>>> ocfs2_inode_lock
>>>> ocfs2_inode_lock_full_nested
>>>> __ocfs2_cluster_lock
>>>> Succeeds and allocates a new dlm lockres.
>>>> ocfs2_clear_inode
>>>> ocfs2_open_unlock
>>>> ocfs2_drop_inode_locks
>>>> ocfs2_drop_lock
>>>> Since lockres has not been initialized, the lock
>>>> can't be dropped and the lockres can't be
>>>> migrated, thus umount will hang forever.
>>>>
>>>> Signed-off-by: Alex Chen <alex.c...@huawei.com>
>>>> Reviewed-by: Joseph Qi <joseph...@huawei.com>
>>>> Reviewed-by: joyce.xue <xuejiu...@huawei.com>
>>>>
>>>> ---
>>>> fs/ocfs2/dlmglue.c | 5 +++++
>>>> 1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
>>>> index 11849a4..8b23aa2 100644
>>>> --- a/fs/ocfs2/dlmglue.c
>>>> +++ b/fs/ocfs2/dlmglue.c
>>>> @@ -1391,6 +1391,11 @@ static int __ocfs2_cluster_lock(struct ocfs2_super
>>>> *osb,
>>>> int noqueue_attempted = 0;
>>>> int dlm_locked = 0;
>>>>
>>>> + if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED)) {
>>>> + mlog_errno(-EINVAL);
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> ocfs2_init_mask_waiter(&mw);
>>>>
>>>> if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
>>>>
>>>
>>>
>>> .
>>>
>>
>
>
> .
>
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