OverlayFS & /usr

[oneiro]

Hello.

I have problem to set/usr as overlayFS using fstab config file.
Error say about try mount /usr into /root/usr but in fstab I do not have such patch.
How to fix the issue?

My fstab file is:

Code: Select all

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# systemd generates mount units based on this file, see systemd.mount(5).
# Please run 'systemctl daemon-reload' after making changes here.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/mmcblk0p2 during installation
UUID=8ff7288e-80d8-41a4-a218-bc10c3ad7e73 /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/mmcblk0p1 during installation
UUID=AC69-A29E  /boot/efi       vfat    umask=0077      0       1
# swap was on /dev/mmcblk0p3 during installation
#UUID=8c547504-27bb-447a-a52d-6c13ebdf6272 none            swap    sw              0       0
UUID=cd3c4889-2593-425f-892f-4ee67efba905       /vm     ext4    defaults        0       1
UUID=588ff93a-8c1b-417c-ae33-371db0ff7f77       /overlay        ext4    defaults        0       1
overlay /root   overlay x-systemd.requires=/overlay,lowerdir=/root,upperdir=/overlay/upper/root,workdir=/overlay/work 0 0
overlay /var    overlay x-systemd.requires=/overlay,lowerdir=/var,upperdir=/overlay/upper/var,workdir=/overlay/work2    0       0
#overlay /usr   overlay x-systemd.requires=/overlay,lowerdir=/usr,upperdir=/overlay/upper/usr,workdir=/overlay/work3    0       0
UUID=87a0ce74-6f2f-409e-ab52-883054d907a2       /backup         ext4    defaults        0       1

As you see overlay for /usr is commented and system working fine with above fstab file but after uncomment the line I got below error and jump into initramfs cmd. The error is:

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Begin: Mounting root file system ... Begin: Running /scripts/local-top .... done
Begin: Running /scripts/local-premount ... [ timestamp]  Btrfs loaded, crc32c-intel, zoned=yes, fseverity
Scanning for Btrfs filesystems
done.
Begin: Will now check root file system ... fsck from util-linux 2.23.1
[/sbin/fsck.ext4 (1) -- /dev/mmcblk0p2] fsck.ext4 -a -C0 /dev/mmcblk0p2
/dev/mmcblk0p2: recovering journal
/dev/mmcblk0p2: clean, 270739/866656 files, 2264529/3465472 blocks
done.
[   timestap EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Quota mode: none.
done.
Begin: Mounting /usr file system ... mount: mounting overlay on /root/usr failed: No such device.
Failed to mount overlay as /usr file system

BTW, found similar issue from 2016 not resolved:

https://www.linuxquestions.org/question ... 175572525/

[oneiro]

Trying to resolver my issue decide use systemd but due to wrong order mounting points cannot jump it.

In my cause to working overlayFS under /usr first is need to have mount /overlay dir. Tested and below working fine, overlayFS is creating under /usr

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mount -t overlay overlay -o,lowerdir=/usr,upperdir=/overlay/upper/usr/,workdir=/overlay/workdir/usr/ /usr

Therefore move two entries from /etc/fstab regarding /overlay dir and /usr overlayFS into systemd units however get error:

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mar 06 01:16:34 debian kernel: overlayfs: failed to resolve '/overlay/upper/usr': -2

Reason is above error appear before /overlay directory is mounted.

My unit files are:

/etc/systemd/system/overlay.mount

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[Unit]
Description=Mount /overlay ext4
Before=local-fs.target
Wants=local-fs.target

[Mount]
What=/dev/disk/by-uuid/d09bf587-a6c9-4116-bdb9-df7a33117f9a
Where=/overlay
Type=ext4
Options=errors=remount-ro
#TimeoutSec=seconds

[Install]
WantedBy=local-fs-pre.target

and

/etc/systemd/system/usr.mount

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[Unit]
Description=Mount OverlaFS /usr
Wants=local-fs.target
After=overaly.mount

[Mount]
What=overlay
Where=/usr
Type=overlay
Options=x-systemd.requires=/overlay,lowerdir=/usr,upperdir=/overlay/upper/usr,workdir=/overlay/workdir/usr
#TimeoutSec=seconds

[Install]
WantedBy=local-fs-pre.target

Can someone help me fix systemd unit files and set properly order of mounting, 1st /overlay and next /usr overlayFS?