"/" partition "Last write time" gets modified before rc.sysinit

leniviy · 2009-10-11 12:45:49

Hi. I've noticed something strange: if I hard reset my PC, the root partition Last write time changes before rc.sysinit is executed and when "/" is still readonly.
I inserted "date" command in the begiining of rc.sysinit and

tune2fs -l /dev/mapper/isw_ebaifefjbf_Volume0p9 | grep "Last write time"

after udev starts (so tune2fs can access my disks).
If the first command (date) prints: 15:00:10
then the second command prints: Last write time: xxx xxx xxx 15:00:09
Who can write data to the disk before mounting readwrite and before rc.sysinit checks the partition?

hungerfish · 2009-10-11 15:43:16

I'm not entirely sure if this could be related, but I found your post just as I was about to post myself...

My issue is as follows:
I've noticed that after a hard-reset, on reboot I'm asked to manually check my partitions (all ext4). The root partition always displays an error about 'last write in future' , which as far as I can understand triggers the promt for a manual chkdsk.
To give an example, the time my system crashed was 15:06, reboot time was maybe 15:10, last write was reported for 17:06.

My system time is bound to localtime, and is as such not utc, however I'm not sure that Germany's localtime +2h is utc, so maybe it isn't relevant anyway..

leniviy · 2009-10-11 17:57:43

hungerfish, same problem as mine. I also got this "superblock last write time is in the future" message, when I had HARDWARECLOCK="localtime".
If you don't have dualboot, you can go back to HARDWARECLOCK="UTC" and forget about this error.

At the beginning the system thinks hwclock is UTC. Then the startup scripts do something with the dirty root partition, and only after that the root partition gets mounted 'ro' and the timezone info is read from it.
In your case, the time "15:06" is written to the disk as UTC and then reported to you converted to German time "17:06".

btw, do you have a soft raid?

Last edited by leniviy (2009-10-11 18:13:05)

hungerfish · 2009-10-11 20:02:53

Sadly I do dualboot, so I need localtime.

Is there anyway to work around this? I never got this kind of error using other distros, so it should be possible somehow!?!

And, no, I don't have a soft raid...

leniviy · 2009-10-11 21:26:28

well, this behaviour seems to be hidden in the 'init'. No chance to change it, but there may be a workaround: temporary adjust system time in the rc.sysinit right before the filesystem is checked and then set it back.

Last edited by leniviy (2009-10-11 21:26:49)

hungerfish · 2009-10-12 01:39:13

There should be away to 'tell' the system, or in this case the chkdsk-tool, 'what time' it is, without the need for the init-stuff to come up. This is begging for a 'fault' in how the timestamps are evaluated, because as mentioned before, I never got this with other distros. Maybe its to-do with some Ext4 feature, because I was using Ext3 up until recently, so maybe thats where the difference lies...but this is just annoying!
(Obviously the hard-locking part is the real bummer here, but it does happen...)

leniviy · 2009-10-12 18:06:30

OK. Here's the plan "A" . You have to modify /etc/rc.sysinit in 2 places.
1) find

# Set clock early to fix some bugs with filesystem checks
# Clock is set again later to match rc.conf
if [ -n "$HWCLOCK_PARAMS" -a -f /etc/localtime ]; then
    /sbin/hwclock $HWCLOCK_PARAMS --noadjfile
fi

and replace it with this:

# Set clock early to fix some bugs with filesystem checks
# Clock is set again later to match rc.conf
SETCLOCKONEMORETIME=
if [ -n "$HWCLOCK_PARAMS" -a -f /etc/localtime ]; then
 # don't set the clock early if rtc is localtime and local time > UTC
 if [ "$HARDWARECLOCK" = "localtime" -a "`date +%z`" -gt "0" ]; then
  echo "Not setting clock early"
  SETCLOCKONEMORETIME=1
 else
    /sbin/hwclock $HWCLOCK_PARAMS --noadjfile
 fi
fi

2) find

stat_busy "Mounting Local Filesystems"

and replace it with this:

if [ -n "$HWCLOCK_PARAMS" -a -f /etc/localtime ]; then
 if [ "$SETCLOCKONEMORETIME" = "1" ]; then
    /sbin/hwclock $HWCLOCK_PARAMS --noadjfile
 fi
fi

stat_busy "Mounting Local Filesystems"

***********************************************
double check the syntax because if this file is broken, the system won't boot. Don't hardreset this time, reboot normally for once.

Arch Linux

#1 2009-10-11 12:45:49

"/" partition "Last write time" gets modified before rc.sysinit

#2 2009-10-11 15:43:16

Re: "/" partition "Last write time" gets modified before rc.sysinit

#3 2009-10-11 17:57:43

Re: "/" partition "Last write time" gets modified before rc.sysinit

#4 2009-10-11 20:02:53

Re: "/" partition "Last write time" gets modified before rc.sysinit

#5 2009-10-11 21:26:28

Re: "/" partition "Last write time" gets modified before rc.sysinit

#6 2009-10-12 01:39:13

Re: "/" partition "Last write time" gets modified before rc.sysinit

#7 2009-10-12 18:06:30

Re: "/" partition "Last write time" gets modified before rc.sysinit

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