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From: Theodore Ts'o <tytso@mit.edu>
To: "Nelson, John R" <John_Nelson@student.uml.edu>
Cc: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: Commit Interval and Delayed Allocation
Date: Fri, 9 Nov 2012 21:58:38 -0500	[thread overview]
Message-ID: <20121110025838.GA5974@thunk.org> (raw)
In-Reply-To: <0408C81F72528E40A0D3235A1F67FFC83ECD9881@SN2PRD0202MB144.namprd02.prod.outlook.com>

On Sat, Nov 10, 2012 at 12:40:42AM +0000, Nelson, John R wrote:
> Hi,
>   Say if ext4 commits every 5 seconds, does this mean whatever is
>buffered for delayed allocation is flushed every 5 seconds as well?

No; there is a separate 30 second timer which is used for writeback
thread.

For ext3 in data=ordered mode, we will flush out dirty pages for
inodes which have been written to make sure that stale data can never
get revealed.

But in delayed allocation, there is no risk that stale data can get
revealed until we actually allocate the data blocks.

	       	  	   	    	- Ted

  reply	other threads:[~2012-11-10  2:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-10  0:40 Commit Interval and Delayed Allocation Nelson, John R
2012-11-10  2:58 ` Theodore Ts'o [this message]
2012-11-13 11:37   ` Peng Tao

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