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From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
	Wu Fengguang <fengguang.wu@intel.com>,
	linux-fsdevel@vger.kernel.org, dchinner@redhat.com
Subject: Re: [PATCH v3] writeback: Do not sync data dirtied after sync start
Date: Wed, 9 Oct 2013 14:21:25 -0700	[thread overview]
Message-ID: <20131009142125.9c7a2b3f5d68ddc6d11c7d3a@linux-foundation.org> (raw)
In-Reply-To: <20131009150325.GA25870@quack.suse.cz>

On Wed, 9 Oct 2013 17:03:25 +0200 Jan Kara <jack@suse.cz> wrote:

> From: Jan Kara <jack@suse.cz>
> 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 <jack@suse.cz>
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 <jack@suse.cz>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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,
_


  reply	other threads:[~2013-10-09 21:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-27  9:44 [PATCH v3] writeback: Do not sync data dirtied after sync start Jan Kara
2013-09-29 23:12 ` Dave Chinner
2013-10-08 22:14 ` Andrew Morton
2013-10-09 14:02   ` Jan Kara
2013-10-09 15:03     ` Jan Kara
2013-10-09 21:21       ` Andrew Morton [this message]
2013-10-09 22:14         ` Jan Kara

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