Re: [PATCH V3 0/8] Cleancache: overview

[Nitin Gupta]

On 07/23/2010 01:46 PM, Minchan Kim wrote:
> On Fri, Jul 23, 2010 at 4:36 PM, Nitin Gupta <ngupta@xxxxxxxxxx> wrote:
>>
>> 2. I think change in btrfs can be avoided by moving cleancache_get_page()
>> from do_mpage_reapage() to filemap_fault() and this should work for all
>> filesystems. See:
>>
>> handle_pte_fault() -> do_(non)linear_fault() -> __do_fault()
>>                                                -> vma->vm_ops->fault()
>>
>> which is defined as filemap_fault() for all filesystems. If some future
>> filesystem uses its own custom function (why?) then it will have to arrange for
>> call to cleancache_get_page(), if it wants this feature.
> 
> 
> filemap fault works only in case of file-backed page which is mapped
> but don't work not-mapped cache page.  So we could miss cache page by
> read system call if we move it into filemap_fault.
> 
> 

Oh, yes. Then we need cleancache_get_page() call in do_generic_file_read() too.
So, if I am missing anything now, we should now be able to get rid of per-fs
changes.

Thanks,
Nitin
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