On 07/23/2013 01:25 PM, Sage Weil wrote:
> On Tue, 23 Jul 2013, Yan, Zheng wrote:
>> On 07/23/2013 09:41 AM, Sage Weil wrote:
>>> On Sun, 21 Jul 2013, Yan, Zheng wrote:
>>>> From: "Yan, Zheng" <zheng.z.yan@intel.com>
>>>>
>>>> The MDS uses caps message to notify clients about deleted inode.
>>>> when receiving a such message, invalidate any alias of the inode.
>>>> This makes the kernel release the inode ASAP.
>>>>
>>>> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
>>>> ---
>>>>  fs/ceph/caps.c | 31 ++++++++++++++++++++++++++++++-
>>>>  1 file changed, 30 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
>>>> index 25442b4..b446fdd 100644
>>>> --- a/fs/ceph/caps.c
>>>> +++ b/fs/ceph/caps.c
>>>> @@ -2334,6 +2334,28 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
>>>>  }
>>>>  
>>>>  /*
>>>> + * Invalidate unlinked inode's aliases, so we can drop the inode
>>>> + * from the cache ASAP.
>>>> + */
>>>> +static void invalidate_aliases(struct inode *inode)
>>>> +{
>>>> +	struct dentry *dn;
>>>> +
>>>> +	dout("invalidate_aliases inode %p\n", inode);
>>>> +	d_prune_aliases(inode);
>>>> +	while ((dn = d_find_alias(inode))) {
>>>> +		d_delete(dn);
>>>> +		dput(dn);
>>>
>>> I don't think this loop is safe.  d_delete() won't unlink the inode if 
>>> there are other refs to the dentry, which would make this get stuck in a 
>>> loop.  Maybe simple checking if we get the same dentry back from 
>>> d_find_alias() as the previous call?
>>>
>>
>> For non-dir inode, d_find_alias() only return connected dentry. After calling
>> d_delete, the dentry become disconnected. so the loop is safe.
> 
> Oh, right.  Totally misread that.
> 
>>>> +		/*
>>>> +		 * for dir inode, d_find_alias() can return
>>>> +		 * disconnected dentry
>>>> +		 */
>>>> +		if (S_ISDIR(inode->i_mode))
>>>> +			break;
>>>> +	}
>>>
>>> If we handle the more general case, I'm not sure we need any special case 
>>> here for the directory... although I confess I'm not sure why disconnected 
>>> dentries should be treated specially at all.
>>>
>>
>> For dir inode, d_find_alias() may disconnected dentry, that's why the special case
>> is needed. how about below code.
> 
> Right.  I think either variation is okay.  I'll pull in the original for 
> now, unless you prefer the below.  Sorry for the runaround!
> 
> sage
> 

please apply the attached version, thanks.

Yan, Zheng