From: =?ISO-8859-15?Q?Luk=E1=A8_Czerner?= Subject: Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags Date: Thu, 25 Oct 2012 11:44:44 +0200 (CEST) Message-ID: References: <1351149943-4827-1-git-send-email-tracek@redhat.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Tomas Racek , linux-ext4@vger.kernel.org, lczerner@redhat.com To: Yongqiang Yang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:18472 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934884Ab2JYJou (ORCPT ); Thu, 25 Oct 2012 05:44:50 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, 25 Oct 2012, Yongqiang Yang wrote: > Date: Thu, 25 Oct 2012 15:44:48 +0800 > From: Yongqiang Yang > To: Tomas Racek > Cc: linux-ext4@vger.kernel.org, lczerner@redhat.com > Subject: Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags > > Does it make sense in no journal mode? I am not sure why it would not ? It only makes changes to the block group descriptors marking block/inode table as unitialized so we can skip then in fsck. Originally it has been only marked uninitialized when we create the file system, but once we use the particular inode table or block group bitmap it become initialized forever, even though it has been completely freed since then. This patch fixes it so it can become uninitialized again (granted that the flag name is not the best). Advantages are that we can skip that in fsck, but also we might save read from disk, because uninitialized descriptors are initialized in memory rather hen read from the disk. So my question is, why do you think this might not make sense in no journal mode ? Maybe I am missing something. Thanks! -Lukas > > Thanks, > Yongqiang. > > On Thu, Oct 25, 2012 at 3:25 PM, Tomas Racek wrote: > > When last inode from bg is freed, set the INODE_UNINIT flag, similarly > > when last block is freed, set BLOCK_UNINIT flag. This can speed up > > subsequent fsck run. > > > > Signed-off-by: Tomas Racek > > --- > > fs/ext4/ialloc.c | 4 ++++ > > fs/ext4/mballoc.c | 4 ++++ > > 2 files changed, 8 insertions(+) > > > > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c > > index 4facdd2..6e4b982 100644 > > --- a/fs/ext4/ialloc.c > > +++ b/fs/ext4/ialloc.c > > @@ -289,6 +289,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode) > > > > count = ext4_free_inodes_count(sb, gdp) + 1; > > ext4_free_inodes_set(sb, gdp, count); > > + > > + if (count == EXT4_INODES_PER_GROUP(sb)) > > + gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT); > > + > > if (is_directory) { > > count = ext4_used_dirs_count(sb, gdp) - 1; > > ext4_used_dirs_set(sb, gdp, count); > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > > index 526e553..28bce35 100644 > > --- a/fs/ext4/mballoc.c > > +++ b/fs/ext4/mballoc.c > > @@ -4665,6 +4665,10 @@ do_more: > > > > ret = ext4_free_group_clusters(sb, gdp) + count_clusters; > > ext4_free_group_clusters_set(sb, gdp, ret); > > + > > + if(ret == EXT4_BLOCKS_PER_GROUP(sb)) > > + gdp->bg_flags |= cpu_to_le16(EXT4_BG_BLOCK_UNINIT); > > + > > ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh); > > ext4_group_desc_csum_set(sb, block_group, gdp); > > ext4_unlock_group(sb, block_group); > > -- > > 1.7.11.7 > > > > -- > > 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 > > > >