I am looking for systemd part of the answers to understand what
is triggering a strange problem. Any help is appreciated.
After mkfs.btrfs creates btrfs filesystem it scans to register the
device in btrfs.ko.
And we have 'btrfs dev scan --forget' command to undo the process of
register.
But the problem is - immediately after 'btrfs dev scan --forget' the
systemd-udevd scans the device again, defeating the purpose of the
forget as show below (scanned-by).
mkfs.btrfs -fq /dev/sdc && btrfs dev scan --forget /dev/sdc
-------------------
kernel: BTRFS: device fsid 8ea20bb2-888a-4b3b-9f4c-1db9117dc219 devid 1
transid 5 /dev/sdc scanned-by mkfs.btrfs
kernel: BTRFS: device fsid 8ea20bb2-888a-4b3b-9f4c-1db9117dc219 devid 1
transid 5 /dev/sdc scanned-by systemd-udevd
-------------------
And the problem does _not_ happen if there is a sleep of 3 secs after
the mkfs.btrfs, as below.
mkfs.btrfs -fq /dev/sdc && sleep 3 && btrfs dev scan --forget /dev/sdc
------------------
kernel: BTRFS: device fsid 601bd01a-5e6b-488a-b020-0e7556c83087 devid 1
transid 5 /dev/sdc scanned-by mkfs.btrfs
------------------
Any idea what happening from the systemd point of view?
Thanks, Anand
