From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-gw0-f49.google.com ([74.125.83.49]) by bombadil.infradead.org with esmtp (Exim 4.72 #1 (Red Hat Linux)) id 1Or8Eq-0002lD-Nv for linux-mtd@lists.infradead.org; Thu, 02 Sep 2010 11:45:53 +0000 Received: by gwb10 with SMTP id 10so101625gwb.36 for ; Thu, 02 Sep 2010 04:45:52 -0700 (PDT) Subject: Re: UBIFS in-place vs out-of-place GC From: Artem Bityutskiy To: Russ Dill In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Thu, 02 Sep 2010 14:45:48 +0300 Message-ID: <1283427948.3085.19.camel@brekeke> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: Linux-MTD Mailing List Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, On Wed, 2010-09-01 at 09:08 -0700, Russ Dill wrote: > I'm doing a bit of research on UBIFS and something I read from a few > sources has me confused regarding garbage collection: > > http://osl.sed.hu/~havasi/ubifs/#gc You should contact Szeged guys and ask them to remove obsolete information. For much more up-to-date information, see http://linux-mtd.infradead.org/doc/ubifs.html#L_documentation > Looking at the source, I can find the code that does the out of place > updates, but I can't find any references to in place updates or > displacement tables. What gives? We do not have displacement tables, that was some old idea which we never implemented. We do not have in-place GC in UBIFS. But we have so-called "in-the-gaps" method which we use during commit to write the FS index when we do not have extra empty LEBs. In the code it corresponds to the 'layout_in_gaps()' function. -- Best Regards, Artem Bityutskiy (Битюцкий Артём)