From: "Aneesh Kumar K.V" Subject: Re: [PATCH] ext4: Support large files Date: Thu, 11 Oct 2007 11:50:10 +0530 Message-ID: <470DC09A.8060006@linux.vnet.ibm.com> References: <1192079462-7830-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20071011060735.GH8122@schatzie.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, Takashi Sato To: Andreas Dilger Return-path: Received: from E23SMTP03.au.ibm.com ([202.81.18.172]:48518 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754180AbXJKGVC (ORCPT ); Thu, 11 Oct 2007 02:21:02 -0400 Received: from sd0109e.au.ibm.com (d23rh905.au.ibm.com [202.81.18.225]) by e23smtp03.au.ibm.com (8.13.1/8.13.1) with ESMTP id l9B6KjSb004441 for ; Thu, 11 Oct 2007 16:20:45 +1000 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by sd0109e.au.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l9B6OKSR262524 for ; Thu, 11 Oct 2007 16:24:20 +1000 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l9B6HqLR029807 for ; Thu, 11 Oct 2007 16:17:53 +1000 In-Reply-To: <20071011060735.GH8122@schatzie.adilger.int> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Andreas Dilger wrote: > On Oct 11, 2007 10:41 +0530, Aneesh Kumar K.V wrote: >> This patch converts ext4_inode i_blocks to represent total >> blocks occupied by the inode in file system block size. >> Earlier the variable used to represent this in 512 byte >> block size. This actually limited the total size of the file. >> >> This is enabled only if the incompat feature flag >> EXT4_FEATURE_INCOMPAT_LARGE_BLOCK is set in super block >> and the kernel is built with CONFIG_LSF. > > NACK. This must be an old version of the patch. The major problem is > that there is no way to incrementally enable this feature, so as soon > as some file needs to be larger than 2TB, it means that the i_blocks > count on EVERY file needs to be updated, or it will be incorrect. > > The updated proposal was to set EXT4_HUGE_FILE_FL on the inodes that > are using fs-blocksize for i_blocks, and if this flag is not set then > use 512-byte i_blocks. This allows the filesystem to be compatible > unless there really are gigantic files. > So how do we calculate ext4_max_size ? Can we do if CONFIG_LSF is set then consider that that i_blocks can be represented using file system block size ? -aneesh