From: "Theodore Ts'o" Subject: [PATCH, E2FSPROGS] Improve ext4 feature descriptions in mke2fs and tune2fs man pages Date: Mon, 31 Mar 2008 19:36:22 -0400 Message-ID: <1207006592-13980-1-git-send-email-tytso@mit.edu> References: <20080325084039.GA10804@webber.adilger.int> Cc: Andreas Dilger , "Theodore Ts'o" To: linux-ext4@vger.kernel.org Return-path: Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:61503 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751460AbYCaXjY (ORCPT ); Mon, 31 Mar 2008 19:39:24 -0400 In-Reply-To: <20080325084039.GA10804@webber.adilger.int> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Andreas Dilger Signed-off-by: Andreas Dilger Signed-off-by: "Theodore Ts'o" --- misc/mke2fs.8.in | 14 +++++++------- misc/tune2fs.8.in | 10 +++++++++- 2 files changed, 16 insertions(+), 8 deletions(-) diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in index 390874c..6cd10b1 100644 --- a/misc/mke2fs.8.in +++ b/misc/mke2fs.8.in @@ -427,13 +427,6 @@ Store file type information in directory entries. .TP .B has_journal Create an ext3 journal (as if using the -.TP -.B uninit_groups -Create a filesystem without initializing all of the groups. This speeds -up filesystem creation time noticably, and can also reduce -.BR e2fsck time -dramatically. This feature causes the filesystem to be read-only in -older kernels is not supported in most Linux kernels, use with caution. .B \-j option). @JDEV@.TP @@ -445,6 +438,13 @@ option). @JDEV@must be created with the same @JDEV@block size as the filesystems that will be using it. .TP +.B uninit_groups +Create a filesystem without initializing all of the groups. This speeds +up filesystem creation time noticably, and can also reduce +.BR e2fsck time +dramatically. This feature is only supported by the ext4 filesystem in +recent Linux kernels. +.TP .B resize_inode Reserve space so the block group descriptor table may grow in the future. Useful for online resizing using diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in index 69da5de..66d9d52 100644 --- a/misc/tune2fs.8.in +++ b/misc/tune2fs.8.in @@ -444,7 +444,9 @@ only supports clearing this filesystem feature. Allow the kernel to initialize bitmaps and inode tables and keep a high watermark for the unused inodes in a filesystem, to reduce .BR e2fsck (8) -time. +time. This first e2fsck run after enabling this feature will take the +full time, but subsequent e2fsck runs will take only a fraction of the +original time, depending on how full the file system is. .RE .IP After setting or clearing @@ -464,6 +466,12 @@ if necessary. After setting the feature, .B e2fsck -D can be run to convert existing directories to the hashed B-tree format. +Enabling certain filesystem features may prevent the filesystem from being +mounted by kernels which do not support those features. In particular the +.BR uninit_groups +and +.BR flex_bg +features are only supported by the ext4 filesystem. .TP .BI \-r " reserved-blocks-count" Set the number of reserved filesystem blocks. -- 1.5.4.1.144.gdfee-dirty