From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH v3] writeback: Do not sync data dirtied after sync start Date: Wed, 9 Oct 2013 14:21:25 -0700 Message-ID: <20131009142125.9c7a2b3f5d68ddc6d11c7d3a@linux-foundation.org> References: <1380275080-31736-1-git-send-email-jack@suse.cz> <20131008151409.6b7415fc9ad7108f5de04873@linux-foundation.org> <20131009140211.GA13650@quack.suse.cz> <20131009150325.GA25870@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Al Viro , Wu Fengguang , linux-fsdevel@vger.kernel.org, dchinner@redhat.com To: Jan Kara Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53869 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751500Ab3JIVV0 (ORCPT ); Wed, 9 Oct 2013 17:21:26 -0400 In-Reply-To: <20131009150325.GA25870@quack.suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, 9 Oct 2013 17:03:25 +0200 Jan Kara wrote: > From: Jan Kara > Date: Wed, 9 Oct 2013 15:41:50 +0200 > Subject: [PATCH] writeback: Use older_than_this_is_set instead of magic > older_than_this == 0 > > Currently we use 0 as a special value of work->older_than_this to > indicate that wb_writeback() should set work->older_that_this to current > time. This works but it is a bit magic. So use a special flag in > work_struct for that. OK. > - if (!work->older_than_this) > + if (!work->older_than_this_is_set) > work->older_than_this = jiffies; It would be logical although presumably unneeded to set older_than_this_is_set here? > Also fixup writeback from workqueue rescuer to include all inodes. There's nothing in the patch which matches this sentence? From: Jan Kara Subject: writeback: use older_than_this_is_set instead of magic older_than_this == 0 Currently we use 0 as a special value of work->older_than_this to indicate that wb_writeback() should set work->older_that_this to current time. This works but it is a bit magic. So use a special flag in work_struct for that. Also fixup writeback from workqueue rescuer to include all inodes. Signed-off-by: Jan Kara Cc: Fengguang Wu Cc: Dave Chinner Signed-off-by: Andrew Morton --- fs/fs-writeback.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff -puN fs/fs-writeback.c~writeback-do-not-sync-data-dirtied-after-sync-start-fix fs/fs-writeback.c --- a/fs/fs-writeback.c~writeback-do-not-sync-data-dirtied-after-sync-start-fix +++ a/fs/fs-writeback.c @@ -39,6 +39,10 @@ struct wb_writeback_work { long nr_pages; struct super_block *sb; + /* + * Write only inodes dirtied before this time. Don't forget to set + * older_than_this_is_set when you set this. + */ unsigned long older_than_this; enum writeback_sync_modes sync_mode; unsigned int tagged_writepages:1; @@ -46,6 +50,7 @@ struct wb_writeback_work { unsigned int range_cyclic:1; unsigned int for_background:1; unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ + unsigned int older_than_this_is_set:1; enum wb_reason reason; /* why was writeback initiated? */ struct list_head list; /* pending work list */ @@ -732,6 +737,8 @@ static long writeback_inodes_wb(struct b .sync_mode = WB_SYNC_NONE, .range_cyclic = 1, .reason = reason, + .older_than_this = jiffies, + .older_than_this_is_set = 1, }; spin_lock(&wb->list_lock); @@ -793,7 +800,7 @@ static long wb_writeback(struct bdi_writ struct inode *inode; long progress; - if (!work->older_than_this) + if (!work->older_than_this_is_set) work->older_than_this = jiffies; spin_lock(&wb->list_lock); @@ -1356,6 +1363,7 @@ void sync_inodes_sb(struct super_block * .sync_mode = WB_SYNC_ALL, .nr_pages = LONG_MAX, .older_than_this = older_than_this, + .older_than_this_is_set = 1, .range_cyclic = 0, .done = &done, .reason = WB_REASON_SYNC, _