From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH] mke2fs: Disallow bigalloc with with bs < 4096 Date: Wed, 3 Apr 2013 10:35:54 -0400 Message-ID: <20130403143554.GA13668@thunk.org> References: <1364997099-22590-1-git-send-email-lczerner@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Lukas Czerner Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:58931 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755456Ab3DCOf7 (ORCPT ); Wed, 3 Apr 2013 10:35:59 -0400 Content-Disposition: inline In-Reply-To: <1364997099-22590-1-git-send-email-lczerner@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Apr 03, 2013 at 03:51:39PM +0200, Lukas Czerner wrote: > Currently there is nothing preventing user to create file system with > bigalloc feature enabled and block size smaller than 4096 Bytes. However > such combination does not make much sense at all because the whole point > of bigalloc is to have bigger allocation units. > > This patch disallow such combination. This makes sense by default but I do see a point in allowing it for testing purposes --- specifically, it allows us to verify that bigalloc works on architectures such as PowerPC and Itanium where page size is greater than the 4k block size. So maybe a developer mode set via mke2fs.conf? Another option would be to enforce that we only support bigalloc file systems where the blocksize == pagesize, but that means we wouldn't be able to mount 4k bigalloc file systems on architectures with a 8k or 16k page size. - Ted