From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: A proposal for making ext4's journal more SMR (and flash) friendly Date: Wed, 8 Jan 2014 18:37:52 -0500 Message-ID: <20140108233752.GD17750@thunk.org> References: <20140108221430.GB21663@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Jan Kara Return-path: Received: from imap.thunk.org ([74.207.234.97]:46937 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757355AbaAHXiD (ORCPT ); Wed, 8 Jan 2014 18:38:03 -0500 Content-Disposition: inline In-Reply-To: <20140108221430.GB21663@quack.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Jan 08, 2014 at 11:14:30PM +0100, Jan Kara wrote: > So when I was thinking about this (already couple of years ago) the thing > which stopped me was the question at which layer we should do the > translation. Ideally we would need something at submit_bh() level but just > wrapping submit_bh() calls inside ext4 isn't enough for stuff like symlinks > or journalled data... Do you have any thoughts on that? I think there are two interfaces that should handle nearly all of our journal block mapping needs. The functions that issue bio requests directly tend to use ext4_get_block*() functions, and functions which use the buffer cache uses submit_bh() (typically via ext4_getblk). There will probably be a few exceptions, but I don't think this should be an intractable problem. Regards, - Ted