linux-kernel - Re: The bug of iput() removal from flusher thread?

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Message-ID: <876251tg3b.fsf@devron.myhome.or.jp>
Date:	Tue, 20 Nov 2012 06:53:12 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Jan Kara <jack@...e.cz>
Cc:	Al Viro <viro@...iv.linux.org.uk>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: The bug of iput() removal from flusher thread?

Jan Kara <jack@...e.cz> writes:

>> >  static void inode_sync_complete(struct inode *inode)
>> >  {
>> > +	/* If inode is clean an unused, put it into LRU now.  */
>> > +	if (!(inode->i_state & I_DIRTY) && !atomic_read(&inode->i_count))
>> > +		inode_lru_list_add(inode);
>> 
>> IMHO, open coding this would be bad idea.
>   Do you mean creating a separate function for the above two lines?

Yes. And the intent is to consolidate "when adds inode to LRU" with
iput_final()'s one.

>> And another one is I_REFERENCED. We really want to remove I_REFERENCED?
>   We don't want I_REFERENCED set - noone used the inode. But looking into
> the code with fresh eyes, the fix isn't as simple as I thought. First I
> need to check MS_ACTIVE and second I need to check I_FREEING... So the
> condition will be complex enough to warrant a separate function.

I can't see the issue (sync_filesystem() will wait I_DIRTY before
MS_ACTIVE, and I_DIRTY prevents I_FREEING) though, it may be possible.
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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