From mboxrd@z Thu Jan  1 00:00:00 1970
From: Edward Shishkin <edward.shishkin@gmail.com>
Subject: Re: [PATCH 3/3] reiser4: in our own sync writes, mark pages dirty
 before marking them writeback.
Date: Mon, 12 Oct 2015 11:07:35 +0200
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To: Ivan Shapovalov <intelfx100@gmail.com>
Cc: Oleg Drokin <green@linuxhacker.ru>, reiserfs-devel@vger.kernel.org

On 10/10/2015 12:44 PM, Ivan Shapovalov wrote:
[...]
> I didn't check the code yet; I'll probably try with that assertion converted into warning and split into two
> (one for formatted and another for unformatted nodes), so that I could check what type of nodes is responsible
> for generating the final oops in set_page_writeback().

I suppose that oops happens on unformatted nodes, because
all formatted nodes have the same host - a special "fake" inode
with number 1, which gets i_wb at mount time (init_fake_inode()
calls inode_attach_wb()).

Edward.

>
>> For unformatted nodes only code review
>> can help. Normally, all modifications of unformatted nodes should
>> look like the following:
>>
>> struct page *page = jnode_page(node);
>> lock_page(page);
>> char *data = kmap(page);
>> /* modifications are going here */
>> kunmap(page);
>> set_page_dirty_nobuffers(page); /* somebody forgets to do this */
>> unlock_page(page);
>>
>> Modifications of formatted nodes should look like the following:
>>
>> longterm_lock_znode(node);
>> zload(node);
>> /* modifications are going here */
>> zrelse(node);
>> znode_make_dirty(node); /* somebody forgets to do this */
>> longterm_unlock_znode();
>>
>> Anyway, we can use your patch 3 as a temporal fixup.
> The most persistent things are those conseived as the most temporary
> ones... ;)