[systemd-devel] fsck checking: passno interpretation problem

[Mariusz Bialonczyk]

Hi
When I was switching to systemd on another debian box I've discovered
a problem related with passno field in fstab.
I have several md partitions (I am using kernel autoassembly for md,
and I am not using initrd).
I have systemd v.25-2 (debian experimental).

I have the following entries in fstab for my partitions:
UUID=f73bcffa-5b89-4f1d-a296-5f0e6ebf4673 /               ext4    errors=remount-ro 0       1
UUID=33a13f77-6e5a-4c1e-b959-d891b0a77488 /home           ext4    defaults        0       2
UUID=45e28f49-1822-4b32-b8a4-2a9ac1bf543e /usr/src        ext4    defaults        0       2
UUID=8fe78553-ad5e-47f1-8630-bf1fa5d7b608 /var            ext4    defaults        0       2
UUID=af8133a0-e9a5-4fcf-81e4-c87c2bb50ac8 none            swap    sw              0       0
all of this UUIDs are /dev/md devices - and not counting the mirroring
disk, all of theese partition is on one physical sata disk.

According to manual all is fine here:
The  sixth field, (fs_passno), is used by the fsck(8) program to deter-
mine the order in which filesystem checks are done at reboot time.  The
root  filesystem  should  be specified with a fs_passno of 1, and other
filesystems should have a fs_passno of 2.  Filesystems within  a  drive
will  be checked sequentially, but filesystems on different drives will
be checked at the same time to utilize  parallelism  available  in  the
hardware.   If  the sixth field is not present or zero, a value of zero
is returned and fsck will assume that the filesystem does not  need  to
be checked.

But this cause a problem to systemd when booting:
systemd-fsck[1346]: /dev/md0: clean, 86170/458752 files, 954201/1834480 blocks
systemd-fsck[3078]: /dev/md2: clean, 312227/1966080 files, 2639961/7864304 blocks (check in 2 mounts)
systemd-fsck[3091]: fsck.ext4: Device or resource busy while trying to open /dev/md4
systemd-fsck[3091]: Filesystem mounted or opened exclusively by another program?
systemd-fsck[3087]: /dev/md1 has been mounted 23 times without being checked, check forced.
systemd-fsck[3087]: /dev/md1: 8010/983040 files (1.2% non-contiguous), 2091221/3932144 blocks
Welcome to emergency mode. Use "systemctl default" or ^D to activate default mode.
Give root password for maintenance
(or type Control-D to continue):

I am not 100% sure but if I remind correctly, the "busy one" partition
was random within reboots.

After conversation with Kay Sievers I've set my fstab entries to this:
UUID=f73bcffa-5b89-4f1d-a296-5f0e6ebf4673 /               ext4    errors=remount-ro 0       1
UUID=33a13f77-6e5a-4c1e-b959-d891b0a77488 /home           ext4    defaults        0       2
UUID=45e28f49-1822-4b32-b8a4-2a9ac1bf543e /usr/src        ext4    defaults        0       3
UUID=8fe78553-ad5e-47f1-8630-bf1fa5d7b608 /var            ext4    defaults        0       4
UUID=af8133a0-e9a5-4fcf-81e4-c87c2bb50ac8 none            swap    sw              0       0

I changed the passno fields to 1,2,3,4,0 from 1,2,2,2,0 and this fixes
the problem and my system is now bootable:
systemd-fsck[1334]: /dev/md0: clean, 86178/458752 files, 954201/1834480 blocks
systemd-fsck[3025]: /dev/md4: clean, 2675040/57581568 files, 199580895/230296816 blocks
systemd-fsck[3109]: /dev/md2 has been mounted 28 times without being checked, check forced.
systemd-fsck[3109]: /dev/md2: 312227/1966080 files (0.4% non-contiguous), 2639961/7864304 blocks
systemd-fsck[3190]: /dev/md1: clean, 8033/983040 files, 2067703/3932144 blocks
Setting console screen modes.
Skipping font and keymap setup (handled by console-setup).
... and login prompt after a while

So the problem is somewhere with passno interpretation (according to
manual it should work, but it doesn't).

regards,
-- 
Mariusz Białończyk
jabber/e-mail: manio at skyboo.net
http://manio.skyboo.net