[Ocfs2-devel] [PATCH] ocfs2: lock the page in __ocfs2_page_mkwrite() -v2

[Tao Ma]

On 12/31/2010 07:32 AM, Joel Becker wrote:
> On Thu, Dec 16, 2010 at 08:56:06PM +0800, Wengang Wang wrote:
>> In ocfs2_grab_pages_for_write() code, there is a comment that
>>
>> 1131                 if (index == target_index&&  mmap_page) {
>> 1132                         /*
>> 1133                          * ocfs2_pagemkwrite() is a little different
>> 1134                          * and wants us to directly use the page
>> 1135                          * passed in.
>> 1136                          */
>> 1137                         lock_page(mmap_page);
>>
>> I guess it's commented by you? So how it "wants" us to use the page
>> passed in?
>> The main purpose of page_mkwrite() is to setup the mapping of page index to
>> sector(block) numbers on the device. I don't see using the page passed in is
>> very important. Correct me if I am wrong.
>> So also for (index == target_index&&  mmap_page) situation, we can use
>> find_or_create_page() just like where it's used in other situation.
>> find_lock_page() takes care of (page->mapping != mapping). How about it?
>
> 	Boy, this is a rabbit hole.  The return codes for page_mkwrite()
> got changed a year ago, and no one updated ocfs2 (or ext4 or gfs2 for
> that matter).  I've emailed Nick about it.
Which patch and why it is a hole? would you mind describing it to me? 
Just curious.

Regards,
Tao