Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757167AbZF3U5W (ORCPT ); Tue, 30 Jun 2009 16:57:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752800AbZF3U5O (ORCPT ); Tue, 30 Jun 2009 16:57:14 -0400 Received: from mail.parknet.ad.jp ([210.171.162.6]:55481 "EHLO mail.officemail.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752612AbZF3U5N (ORCPT ); Tue, 30 Jun 2009 16:57:13 -0400 From: OGAWA Hirofumi To: steve@digidescorp.com Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] FAT: optimize FSINFO writeback References: <1246392130-4261-1-git-send-email-steve@digidescorp.com> Date: Wed, 01 Jul 2009 05:57:15 +0900 In-Reply-To: <1246392130-4261-1-git-send-email-steve@digidescorp.com> (steve@digidescorp.com's message of "Tue, 30 Jun 2009 15:02:10 -0500") Message-ID: <87ocs5h238.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Anti-Virus: Kaspersky Anti-Virus for MailServers 5.5.10/RELEASE, bases: 24052007 #308098, status: clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1821 Lines: 57 steve@digidescorp.com writes: > Only write the FSINFO block back to disk when its contents change. > This optimization can be important when the underlying physical media > can wear out, i.e. Flash. I have no objection to this though. Was this tested on recent version? Well, now, we are using sb->s_dirty for fsinfo, so I'm wondering why this happen frequently. Thanks. > Signed-off-by: Steven J. Magnani > --- > diff -uprN a/fs/fat/misc.c b/fs/fat/misc.c > --- a/fs/fat/misc.c 2009-06-29 11:12:40.000000000 -0500 > +++ b/fs/fat/misc.c 2009-06-29 11:46:45.000000000 -0500 > @@ -61,11 +61,25 @@ void fat_clusters_flush(struct super_blo > le32_to_cpu(fsinfo->signature2), > sbi->fsinfo_sector); > } else { > - if (sbi->free_clusters != -1) > - fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); > - if (sbi->prev_free != -1) > - fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); > - mark_buffer_dirty(bh); > + char write_needed = 0; > + __le32 le_value; > + > + if (sbi->free_clusters != -1) { > + le_value = cpu_to_le32(sbi->free_clusters); > + if (fsinfo->free_clusters != le_value) { > + fsinfo->free_clusters = le_value; > + write_needed = 1; > + } > + } > + if (sbi->prev_free != -1) { > + le_value = cpu_to_le32(sbi->prev_free); > + if (fsinfo->next_cluster != le_value) { > + fsinfo->next_cluster = le_value; > + write_needed = 1; > + } > + } > + if (write_needed) > + mark_buffer_dirty(bh); > } > brelse(bh); > } > -- OGAWA Hirofumi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/