xfs
[Top] [All Lists]

Re: [PATCH-v4 2/7] vfs: add support for a lazytime mount option

To: Jan Kara <jack@xxxxxxx>
Subject: Re: [PATCH-v4 2/7] vfs: add support for a lazytime mount option
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Fri, 28 Nov 2014 00:36:56 -0500
Cc: Linux Filesystem Development List <linux-fsdevel@xxxxxxxxxxxxxxx>, Ext4 Developers List <linux-ext4@xxxxxxxxxxxxxxx>, Linux btrfs Developers List <linux-btrfs@xxxxxxxxxxxxxxx>, XFS Developers <xfs@xxxxxxxxxxx>
Delivered-to: xfs@xxxxxxxxxxx
Dkim-signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=pW4+9IUnGp0BdGgYJJkbRbe/KBELQT+eOxf7rm5la4w=; b=yn3dfE8VQukzpeqAaXCTbfgAfX18nCcZIZV7ecIwE/nhCvuuHeFfw0CxpDibGhNFygBOqGkRxFJAu7VqYd0azezT+9mqi1xDHU9M2xnAZGs3NVdRLfCSCaH5r5DNAlxNTsDr5Ec++fL2oSjA/spf5oYIl3LKKTjGyrHZcX0IjpI=;
In-reply-to: <20141127230016.GH14091@xxxxxxxxx>
References: <1416997437-26092-1-git-send-email-tytso@xxxxxxx> <1416997437-26092-3-git-send-email-tytso@xxxxxxx> <20141127131421.GE30152@xxxxxxxxxxxxx> <20141127230016.GH14091@xxxxxxxxx>
User-agent: Mutt/1.5.23 (2014-03-12)
On Thu, Nov 27, 2014 at 06:00:16PM -0500, Theodore Ts'o wrote:
> Well.... it's not quite enough.  The problem is that for ext3 and
> ext4, the actual work of writing the inode happens in dirty_inode(),
> not in write_inode().  Which means we need to do something like this.
> 
> I'm not entirely sure whether or not this is too ugly to live;
> personally, I think my hack of handling this in update_time() might be
> preferable....

.... and this doesn't work because it breaks ext3/ext4's transaction
handling, since the writeback thread could be racing against some
transactional update of the inode.  So I don't see a way of making the
queue_io / move_expired_inodes approach to the 24 hour time being
tractable.

So the alternatives that I can see at this point is either give up on
the 24 hour timeout, or we fall back to handling this in
update_time().

                                        - Ted

<Prev in Thread] Current Thread [Next in Thread>