From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dd23508.kasserver.com ([85.13.143.21]) by bombadil.infradead.org with esmtp (Exim 4.69 #1 (Red Hat Linux)) id 1NIJH5-0005Fs-7x for linux-mtd@lists.infradead.org; Wed, 09 Dec 2009 09:56:03 +0000 Message-ID: <4B1F7427.10002@stud.tu-ilmenau.de> Date: Wed, 09 Dec 2009 10:55:51 +0100 From: Andre Puschmann MIME-Version: 1.0 To: dedekind1@gmail.com Subject: Re: UBIFS on Atmel Dataflash References: <1260348786.19669.1231.camel@localhost> In-Reply-To: <1260348786.19669.1231.camel@localhost> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Artem, thanks for your prompt reply. Artem Bityutskiy wrote: > Yeah, I had a feeling we should not have assumed power of 2. But it was > so appealing, because we can avoid (slow) divisions when aligning data > to min. I/O unit boundary. I knew about DataFlash, but it is usually so > small that I did not expect anyone using UBIFS there. > > Are you sure you want ubifs on such a tiny flash? We were really > targeting to larger ones, say, starting from 64MiB at least. > Mmh, the idea to run UBIFS came up due to a problem with JFFS2 on this device. So I wanted to use another writeable flash fs to find out whether its a fs-problem or a mtd/dataflash one. So you suggest to stick with JFFS2 in this case? > Basically, there is not fundamental reasons not to support non-power of > 2 min. I/O unit size, besides of optimizations. And to fix this, one > would need to carefully look at / grep for min_io_size usage in both > UBI/UBIFS, and change stuff like ALIGN(x, c->min_io_size) to something > else. But there are very many of such places. > Thanks for your explanation. Best regards, Andre