[Unionfs] Re: [PATCH -mm] unionfs: build fixes

[Ian Kent]

Ian Kent wrote:
> On Tue, 2008-07-29 at 21:02 -0400, Erez Zadok wrote:
>   
>> In message <20080729172216.84e958f7.akpm at linux-foundation.org>, Andrew Morton writes:
>>     
>>> On Tue, 29 Jul 2008 19:12:47 +0100 (BST)
>>> Hugh Dickins <hugh at veritas.com> wrote:
>>>
>>>       
>>>> Get unionfs building and working in mmotm with the 2.6.27-rc1 VFS changes:
>>>> permission() has been replaced by inode_permission() without nameidata arg;
>>>> unionfs_permission() without nameidata arg; vfs_symlink() without mode arg;
>>>> LOOKUP_ACCESS no longer defined; and kmem_cache_create() no longer passes
>>>> kmem_cachep to the init_once() constructor.
>>>>
>>>> Note: while okay for inclusion in -mm for now, unionfs_permission() mods
>>>> will need review and perhaps correction by Erez: without a nameidata arg,
>>>> some locking vanishes from unionfs_permission(), and a MNT_NOEXEC check on
>>>> its lower_inode; I have not studied the VFS changes enough to tell whether
>>>> that amounts to a real issue for unionfs, or just removal of dead code.
>>>>         
>>> thanks.
>>>
>>>       
>>>> This should follow git-unionfs.patch
>>>> I notice my unionfs-fix-memory-leak.patch
>>>> and fsstack-fsstack_copy_inode_size-locking.patch
>>>> are currently commented out, yet I don't recall the
>>>> mm-commits dispatch rider bringing me a telegram to explain why?
>>>>         
>>> git-unionfs got commented out because of some upstream git (or build)
>>> catastrophe.  So its fixes got comemnted out too.  Then git-unionfs was
>>> restored but I forgot to manually restore the followon fixes.  It
>>> happens.
>>>       
>> Shortly I'm going to post fixes which include Hugh's stuff and more.  Sorry
>> for the delay.
>>
>>     
>>> I must say that I'm not really sure why we're struggling along with
>>> unionfs.  Last I heard there were fundamental, unresolveable design
>>> disagreements with the VFS guys.  Those issues should be where 100% of
>>> the effort is being devoted, but instead we seem to be cruising along
>>> in a different direction?
>>>       
>> Some of my upcoming patches begin to address this (took longer than
>> expected):
>>
>> - extracting all whiteout related code into callable methods in unionfs, so
>>   that I can "drop in" the new whiteout code that Bharata et al. are
>>   reportedly working on.  I really hope to see some new whiteout code in -mm
>>   soon.  Bharata?
>>
>> - reworking the lookup code to handle vfsmounts: this'll be needed when we
>>   switch from vfs_* to path_* (Miklos's patches).
>>
>> As for other fundamental issues, I've been posting some suggestions in
>> recent months.  For example
>>
>> - the need for cleaner handling of vma->fault(), a relatively minor patch I
>>   posted, based on hch's LSF08 suggestions.  Got no response from any of the
>>   VFS folks.
>>
>> - a post I made regarding suggestions on how to handle lower f/s changes,
>>   based on Viro's LSF08 comments: to have a superblock level writers count
>>   (I suggested that it's a superset of the superblock->s_vfs_rename_mutex,
>>   and perhaps be elevated to be one).  Again, got no responses from anyone
>>   on the VFS team.
>>     
>
> Erez, do you have links to email threads or a commentary of the things
> that are causing concern somewhere?
>
> I spotted one but it seems light on for descriptive value (or maybe it's
> me who's light on for understanding, ;)).
>
>   

Erez,

Can't you help me out here?
A brief summary of claimed, fixed and planned to be fixed issues would 
be really good.

Ian