From: "Darrick J. Wong" Subject: Re: [PATCH 01/02] ext2: reserve INCOMPAT_INLINEDATA feature flag Date: Tue, 6 Dec 2011 16:39:32 -0800 Message-ID: <20111207003932.GI7137@tux1.beaverton.ibm.com> References: Reply-To: djwong@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Theodore Ts'o" , ext4 development , Liang Zhen , Tao Ma To: Andreas Dilger Return-path: Received: from e38.co.us.ibm.com ([32.97.110.159]:60813 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754053Ab1LGAkx (ORCPT ); Tue, 6 Dec 2011 19:40:53 -0500 Received: from /spool/local by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 6 Dec 2011 17:40:52 -0700 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pB70dYdZ173610 for ; Tue, 6 Dec 2011 17:39:34 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pB70dXsZ007356 for ; Tue, 6 Dec 2011 17:39:33 -0700 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Dec 06, 2011 at 05:13:51PM -0700, Andreas Dilger wrote: > Reserve the EXT4_FEATURE_INCOMPAT_INLINEDATA feature flag for use > with storing small file data in the i_blocks field (up to 60 bytes) > and/or the large xattr space (after i_extra_isize, up to the large > inode size). On typical filesystems this can save 1-3% of the space, > and more importantly it also avoids seeking to read the data block. > > This will become increasingly important with bigalloc filesystems, > since they consume a full cluster of blocks for each file, including > small directories that could easily fit into the inode itself. > > Signed-off-by: Andreas Dilger > Originally-by: Tao Ma > --- > lib/ext2fs/ext2_fs.h | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h > index 0f8cde8..6cf47f9 100644 > --- a/lib/ext2fs/ext2_fs.h > +++ b/lib/ext2fs/ext2_fs.h > @@ -719,6 +719,7 @@ struct ext2_super_block { > #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200 > #define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400 > #define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000 > +#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */ I was using 0x2000 for EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM, to change the block group checksum to use crc32c. --D > > #define EXT2_FEATURE_COMPAT_SUPP 0 > #define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \ > -- > 1.7.2 > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >