linux-ext4 - Re: [PATCH,RFC] ext4: add lazytime mount option

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Message-ID: <54646F8B.8040000@plexistor.com>
Date:	Thu, 13 Nov 2014 10:44:59 +0200
From:	Boaz Harrosh <boaz@...xistor.com>
To:	Dave Chinner <david@...morbit.com>, Theodore Ts'o <tytso@....edu>
CC:	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH,RFC] ext4: add lazytime mount option

On 11/13/2014 08:41 AM, Dave Chinner wrote:
<>
> 
> I think this needs to a VFS level inode timestamp update option.
> The games ext4 is playing with reference counts inside .drop_inode are
> pretty nasty and could be avoided if this is implemented at the VFs
> level..
> 
> I think that the "lazy time update" status should really be tracked
> in the inode->i_state field. Something like lazytime updates do not
> call ->update_inode, nor do they mark the inode dirty, but they do
> update the inode->i_[acm]time fields and set a TIMEDIRTY state flag.
> 
> Then when the filesystem next logs or writes the inode it can
> log those fields and clear the TIMEDIRTY flag, or if iput_final()
> sees that flag it can call ->update_time directly to get the
> filesystem to run a transaction to update the timestamps before the
> inode is evicted from cache.
> 
> That way the same update semantics can be easily implemented on all
> filesystems, and filesystems that already implement update_time
> should work without any modification at all...
> 

+1 Like from Boaz. I think Dave is very much right!

> Cheers,

Indeed
Boaz

> Dave.
<>

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