From mboxrd@z Thu Jan  1 00:00:00 1970
From: wengang wang <wen.gang.wang@oracle.com>
Date: Tue, 23 Sep 2008 13:27:26 +0800
Subject: [Ocfs2-devel] [PATCH 1/1] OCFS2: unhash all dentries on a inode.
In-Reply-To: <48D874CC.1020402@oracle.com>
References: <200809220948.m8M9mE0T004547@wengang.cn.oracle.com>
	<48D8121C.20503@oracle.com> <48D84BBF.5060503@oracle.com>
	<48D874CC.1020402@oracle.com>
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To: ocfs2-devel@oss.oracle.com

Sunil Mushran wrote:
> If so, won't that be a bug?
>
If you meant my patch is bug, why?
unhashing dentry from dentry cache only leads to a mis-match in that 
cache when a new request comes.
when the dentry is not found in cache, before creating a new dentry, a 
validation check should be done on the inode in inode cache or by 
ocfs2_lookup().
so I think there is no problem.

without unhashing the dentries, dput() won't call dentry_iput(). thus 
the stale inode will be kept in memory for ever. --this is a problem.

thanks,
wengang.
> wengang wang wrote:
>> Sunil,
>>
>> d_prune_aliases() unhashes dentries that has 0 reference count, 
>> dentries with non-zero ref count won't be unhashed.
>> My code unhashes all no matter there reference counts are 0 or not.
>>
>> regards,
>> wengang.
>>
>> Sunil Mushran wrote:
>>> NAK.
>>>
>>> I fail to understand your logic. The code you've added is pretty
>>> much what d_prune_aliases() does (the call you have deleted).
>>>
>>> wangang wang wrote:
>>>> In ocfs2_process_delete_request(), we should unhash all dentries on 
>>>> the inode.
>>>> --not only the ones with 0 referrence count. so that it's possible 
>>>> for dput()
>>>> to drop the stale inode.
>>>>
>>>> the patch is against 1.2 svn.
>>>>
>>>> Signed-off-by: Wengang wang <wen.gang.wang@oracle.com>
>>>> -- 
>>>>
>>>> Index: fs/ocfs2/vote.c
>>>> ===================================================================
>>>> --- fs/ocfs2/vote.c    (revision 3101)
>>>> +++ fs/ocfs2/vote.c    (working copy)
>>>> @@ -176,6 +176,7 @@
>>>>                      int deleting_node)
>>>>  {
>>>>      int response = OCFS2_RESPONSE_BUSY;
>>>> +    struct list_head *tmp, *head;
>>>>  
>>>>      mlog(0, "DELETE vote on inode %lu, read lnk_cnt = %u, slot = 
>>>> %d\n",
>>>>           inode->i_ino, inode->i_nlink, *orphaned_slot);
>>>> @@ -253,9 +254,19 @@
>>>>      ocfs2_mark_inode_remotely_deleted(inode, deleting_node);
>>>>      spin_unlock(&OCFS2_I(inode)->ip_lock);
>>>>  
>>>> -    /* Not sure this is necessary anymore. */
>>>> -    d_prune_aliases(inode);
>>>> +    /* unhash all dentries on this inode */
>>>> +    spin_lock(&dcache_lock);
>>>> +    head = &inode->i_dentry;
>>>> +    tmp = head;
>>>>  
>>>> +    while ((tmp = tmp->next) != head) {
>>>> +        struct dentry *dentry = list_entry(tmp, struct dentry, 
>>>> d_alias);
>>>> +        spin_lock(&dentry->d_lock);
>>>> +        __d_drop(dentry);
>>>> +        spin_unlock(&dentry->d_lock);
>>>> +    }
>>>> +    spin_unlock(&dcache_lock);
>>>> +
>>>>      /* If we get here, then we're voting 'yes', so commit the
>>>>       * delete on our side. */
>>>>      response = OCFS2_RESPONSE_OK;
>>>>
>>>> _______________________________________________
>>>> Ocfs2-devel mailing list
>>>> Ocfs2-devel at oss.oracle.com
>>>> http://oss.oracle.com/mailman/listinfo/ocfs2-devel
>>>>   
>>>
>>
>

-- 
Wengang Wang
Member of Technical Staff
Oracle Asia R&D Center
Open Source Technologies Development

Tel:      +86 10 8278 6265
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