File system currently unmounted, but mount failed due to 'Device busy'

All of a sudden today, the system booted into emergency mode because mounting /media/mydata failed. $ cat /proc/mounts did not list this as a mount point. I commented out the relevant line in the etc/fstab file and booted. File after commenting this out:

#
# 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).
#
# <file system>             <mount point>  <type>  <options>  <dump>  <pass>
UUID=Fxxxxx                           /boot/efi      vfat    umask=0077 0 2
#UUID=2xxxxx                    /media/mydata  ntfs    defaults,noatime 0 2
UUID=fxxxxx swap           swap    defaults,noatime 0 0
UUID=6xxxxx /              ext4    defaults,noatime 0 1
tmpfs                                     /tmp           tmpfs   defaults,noatime,mode=1777 0 0

After booting, I checked the mounted filesystems: $ cat /proc/mounts
Which gave

sys /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
dev /dev devtmpfs rw,nosuid,relatime,size=7824588k,nr_inodes=1956147,mode=755,inode64 0 0
run /run tmpfs rw,nosuid,nodev,relatime,mode=755,inode64 0 0
efivarfs /sys/firmware/efi/efivars efivarfs rw,nosuid,nodev,noexec,relatime 0 0
/dev/nvme0n1p7 / ext4 rw,noatime 0 0
securityfs /sys/kernel/security securityfs rw,nosuid,nodev,noexec,relatime 0 0
tmpfs /dev/shm tmpfs rw,nosuid,nodev,inode64 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot 0 0
pstore /sys/fs/pstore pstore rw,nosuid,nodev,noexec,relatime 0 0
bpf /sys/fs/bpf bpf rw,nosuid,nodev,noexec,relatime,mode=700 0 0
systemd-1 /proc/sys/fs/binfmt_misc autofs rw,relatime,fd=37,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=14770 0 0
mqueue /dev/mqueue mqueue rw,nosuid,nodev,noexec,relatime 0 0
debugfs /sys/kernel/debug debugfs rw,nosuid,nodev,noexec,relatime 0 0
tracefs /sys/kernel/tracing tracefs rw,nosuid,nodev,noexec,relatime 0 0
hugetlbfs /dev/hugepages hugetlbfs rw,nosuid,nodev,relatime,pagesize=2M 0 0
configfs /sys/kernel/config configfs rw,nosuid,nodev,noexec,relatime 0 0
fusectl /sys/fs/fuse/connections fusectl rw,nosuid,nodev,noexec,relatime 0 0
/dev/loop2 /var/lib/snapd/snap/atom/286 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop1 /var/lib/snapd/snap/chess-tactics-and-strategy/2 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop0 /var/lib/snapd/snap/bare/5 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop3 /var/lib/snapd/snap/core18/2796 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop4 /var/lib/snapd/snap/core18/2812 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop5 /var/lib/snapd/snap/gnome-3-28-1804/194 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop8 /var/lib/snapd/snap/gtk-common-themes/1535 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop7 /var/lib/snapd/snap/core20/2182 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop6 /var/lib/snapd/snap/gnome-3-28-1804/198 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop10 /var/lib/snapd/snap/snapd/20671 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
/dev/loop11 /var/lib/snapd/snap/snapd/21184 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0
tmpfs /tmp tmpfs rw,noatime,inode64 0 0
binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,nosuid,nodev,noexec,relatime 0 0
/dev/nvme0n1p1 /boot/efi vfat rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 0
tmpfs /run/user/1000 tmpfs rw,nosuid,nodev,relatime,size=1566568k,nr_inodes=391642,mode=700,uid=1000,gid=1000,inode64 0 0
gvfsd-fuse /run/user/1000/gvfs fuse.gvfsd-fuse rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0
portal /run/user/1000/doc fuse.portal rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0
/dev/loop12 /var/lib/snapd/snap/core20/2264 squashfs ro,nodev,relatime,errors=continue,threads=single 0 0

There is no /media/mydata mount point. Then I tried to mount:
$ sudo mount -t ntfs /dev/nvme0n1p5 /media/mydata.
It says
fuse: mount failed: Device or resource busy
But it is not even mounted! How can it be busy? I tried to kill any possibly running processes with $ sudo fuser -k /media/mydata, which returned nothing.

Now how can I mount this partition? Please help!

Try changing the type from ntfs to ntfs3.

If the issue persists, there is a note in Stable Update 2024-04-04 announcements that might apply to you; See:

I hope this helps. Cheers.

Thanks a lot for the reply! You are correct that the issue is specific to Kernel 6.8. Everything is fine if I boot into Kernel 6.6.

I tried to follow the solution mentioned in the announcement you have pointed to. But it does not seem to be working. Can you please check if I am doing this right? I have edited my /etc/fstab file to the following. Do I need to do anything else?

#
# 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).
#
# <file system>             <mount point>  <type>  <options>  <dump>  <pass>
UUID=Fxxxxx                            /boot/efi      vfat    umask=0077 0 2
UUID=2xxxxx                    /media/mydata  ntfs3   rw,nosuid,nodev,noatime,uid=0,gid=0,umask=000,blksize=4096 0 2
UUID=fxxxxx swap           swap    defaults,noatime 0 0
UUID=6xxxxx /              ext4    defaults,noatime 0 1
tmpfs                                     /tmp           tmpfs   defaults,noatime,mode=1777 0 0

Remove those.
You already have umask (which should be umask=0000) and should suffice for NTFS.

This would also be as good as any (again, for NTFS):

defaults,rw,noatime,umask=0000,windows_names

Most welcome. Glad to help.
I’d appreciate a little tick under my post above, when you’re ready, so we can mark the issue as solved. Cheers.