linux-ext4 - Re: Lazytime undone by/not working with remount?

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Message-ID: <pan.2015.05.16.14.26.22@googlemail.com>
Date:	Sat, 16 May 2015 14:26:22 +0000 (UTC)
From:	Holger Hoffstätte 
	<holger.hoffstaette@...glemail.com>
To:	linux-ext4@...r.kernel.org
Subject: Re: Lazytime undone by/not working with remount?


(cc: kzak)

On Sat, 16 May 2015 11:05:04 +0000, Holger Hoffstätte wrote:

> Hi,
> 
> playing with lazytime on 4.0.4-rc1 + yesterday's fencepost patch) I noticed
> something odd. Mounting secondary (non-root) partitions with lazytime works
> fine, but / does not seem to retain the value from fstab - apparently because
> it is remounted rw during boot, and lazytime gets swallowed/undone.
> 
> Same effect when trying to remount manually with lazytime:
> 
> tux>findmnt /
> TARGET SOURCE    FSTYPE OPTIONS
> /      /dev/sda1 ext4   rw,noatime
> 
> tux>mount -o lazytime,remount / 
> 
> tux>dmesg 
> [ 5208.482505] EXT4-fs (sda1): re-mounted. Opts: (null)
> 
> tux>findmnt /                  
> TARGET SOURCE    FSTYPE OPTIONS
> /      /dev/sda1 ext4   rw,noatime
> 
> tux>mount --version
> mount from util-linux 2.26.2 (libmount 2.26.0: assert, debug)
> 
> Newly mounting unmounted partitions works fine.
> 
> Any ideas?

This turned out to be a regression in util-linux 2.26.x. :-(
I downgraded to 2.25.2 and behold:

tux>findmnt /   
TARGET SOURCE    FSTYPE OPTIONS
/      /dev/sda1 ext4   rw,noatime

tux>mount -o remount,lazytime /

root>findmnt /                  
TARGET SOURCE    FSTYPE OPTIONS
/      /dev/sda1 ext4   rw,noatime,lazytime

Sorry for the noise.

Holger

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