[Pvfs2-developers] patch: namei bug fixes

[Sam Lang]

On Apr 4, 2007, at 4:37 PM, Phil Carns wrote:

>
>> Hi Phil,
>> Good idea to look at the other file systems.  My (admittedly  
>> limited)  understanding of disconnected dentries is based on the  
>> Documentation/ filesystems/Exporting doc, which may be a bit  
>> outdated.  It suggests  that lookup should return whatever  
>> d_splice_alias returns (assuming  the inode exists), which may  
>> return NULL when the dentry is  disconnected?
>> Also, it seems clear that ENOENT cases require returning NULL.
>> -sam
>
> Ok, I think we are converging on something here :)  Your latest  
> namei3 patch seems to do what you describe, except for the part  
> about returning whatever d_splice_alias() returns.  I experimented  
> by modifying line 213 of namei.c after applying your patch, so that  
> rather than returning "NULL", it returns "res".
>
> On 2.6 kernels, this still passes all LTP tests and handles  
> deleting renamed directories without complaint.  On 2.4 kernels it  
> causes a kernel crash when deleting renamed directories.  I think  
> both of these results confirm what we see from other file systems:  
> on 2.6 we should pass along the return code of d_splice_alias(),  
> while on 2.4 we should always return NULL.
>
> I doubt that there is a feature test for this- kinda hard to tell  
> when there is a semantic change to the vfs lookup function.
>
> Do you think that we should go with your patch plus a "#ifdef  
> PVFS2_LINUX_KERNEL_2_4" wrapper to control whether it returns NULL  
> or res on that one line?

Yeah.  Sounds good to me.  I can commit unless there are other  
objections.

-sam

>
> -Phil
>