From: Theodore Ts'o <tytso@mit.edu>
To: Christoph Hellwig <hch@infradead.org>
Cc: Linux Filesystem Development List <linux-fsdevel@vger.kernel.org>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
Jan Kara <jack@suse.cz>,
Linux btrfs Developers List <linux-btrfs@vger.kernel.org>,
XFS Developers <xfs@oss.sgi.com>
Subject: Re: [PATCH-v4 1/7] vfs: split update_time() into update_time() and write_time()
Date: Tue, 2 Dec 2014 10:09:12 -0500 [thread overview]
Message-ID: <20141202150912.GA3496@thunk.org> (raw)
In-Reply-To: <20141202092033.GA29712@infradead.org>
On Tue, Dec 02, 2014 at 01:20:33AM -0800, Christoph Hellwig wrote:
> Why do you need the additional I_DIRTY flag? A "lesser"
> __mark_inode_dirty should never override a stronger one.
Agreed, will fix.
> Otherwise this looks fine to me, except that I would split the default
> implementation into a new generic_update_time helper.
Sure, I can do that.
> > XFS doesn't have a ->dirty_time yet, but that way XFS would be able to
> > use the I_DIRTY_TIME flag to log the journal timestamps if it so
> > desires, and perhaps drop the need for it to use update_time().
>
> We will probably always need a ->update_time to proide proper locking
> around the timestamp updates.
Couldn't you let the VFS set the inode timesstamps and then have xfs's
->dirty_time(inode, I_DIRTY_TIME) copy the timestamps to the on-disk
inode structure under the appropriate lock, or am I missing something?
> In the current from the generic lazytime might even be a loss for XFS as
> we're already really good at batching updates from multiple inodes in
> the same cluster for the in-place writeback, so I really don't want
> to just enable it without those optimizations without a lot of testing.
Fair enough; it's not surprising that this might be much more
effective as an optimization for ext4, for no other reason that
timestamp updates are so much heavyweight for us. I suspect that it
should be a win for btrfs, though, and it should definitely be a win
for those file systems that don't use journalling at all.
- Ted
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next prev parent reply other threads:[~2014-12-02 15:09 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-26 10:23 [PATCH-v4 0/7] add support for a lazytime mount option Theodore Ts'o
2014-11-26 10:23 ` [PATCH-v4 1/7] vfs: split update_time() into update_time() and write_time() Theodore Ts'o
2014-11-26 19:23 ` Christoph Hellwig
2014-11-27 12:34 ` Jan Kara
2014-11-27 15:25 ` Christoph Hellwig
2014-11-27 14:41 ` Theodore Ts'o
2014-11-27 15:28 ` Christoph Hellwig
2014-11-27 15:33 ` Theodore Ts'o
2014-11-27 16:49 ` Christoph Hellwig
2014-11-27 20:27 ` Theodore Ts'o
2014-12-01 9:28 ` Christoph Hellwig
2014-12-01 15:04 ` Theodore Ts'o
2014-12-01 17:18 ` David Sterba
2014-12-02 9:20 ` Christoph Hellwig
2014-12-02 15:09 ` Theodore Ts'o [this message]
2014-11-26 10:23 ` [PATCH-v4 2/7] vfs: add support for a lazytime mount option Theodore Ts'o
2014-11-27 13:14 ` Jan Kara
2014-11-27 20:19 ` Theodore Ts'o
2014-11-28 12:41 ` Jan Kara
2014-11-27 23:00 ` Theodore Ts'o
2014-11-28 5:36 ` Theodore Ts'o
2014-11-28 16:24 ` Jan Kara
2014-11-26 10:23 ` [PATCH-v4 3/7] vfs: don't let the dirty time inodes get more than a day stale Theodore Ts'o
2014-11-26 10:23 ` [PATCH-v4 4/7] vfs: add lazytime tracepoints for better debugging Theodore Ts'o
2014-11-26 10:23 ` [PATCH-v4 5/7] vfs: add find_active_inode_nowait() function Theodore Ts'o
2014-11-26 10:23 ` [PATCH-v4 6/7] ext4: add support for a lazytime mount option Theodore Ts'o
2014-11-26 19:24 ` Christoph Hellwig
2014-11-26 22:48 ` Dave Chinner
2014-11-26 23:10 ` Andreas Dilger
2014-11-26 23:35 ` Dave Chinner
2014-11-27 13:27 ` Jan Kara
2014-11-27 13:32 ` Jan Kara
2014-11-27 15:25 ` Theodore Ts'o
2014-11-27 15:41 ` Jan Kara
2014-11-27 20:13 ` Theodore Ts'o
2014-11-26 10:23 ` [PATCH-v4 7/7] btrfs: add an is_readonly() so btrfs can use common code for update_time() Theodore Ts'o
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