kern/60762: rump mounted ext2 filesystem shows zero size with df command

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>Number:         60762
>Category:       kern
>Synopsis:       rump mounted ext2 filesystem shows zero size with df command
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Sep 22 06:15:00 +0000 2026
>Originator:     Ramiro Aceves
>Release:        11.0_RELEASE
>Organization:
>Environment:
NetBSD netbsd-nuc.home 11.0 NetBSD 11.0 (GENERIC) #0: Thu Jul 30 15:23:12 UTC 2026  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
Hello:

Ext2 filesystem in /dev/sd0e mounted with rump works fine but df command shows wrong size and 100% full:

netbsd-nuc# df -h
Filesystem     Size   Used  Avail %Cap Mounted on
/dev/dk4       192G    96G    87G  53% /
tmpfs          4.0G     0B   4.0G   0% /tmp
kernfs         1.0K   1.0K     0B 100% /kern
ptyfs          1.0K   1.0K     0B 100% /dev/pts
procfs         4.0K   4.0K     0B 100% /proc
tmpfs          4.0G     0B   4.0G   0% /var/shm

netbsd-nuc# mount /dev/sd0e /mnt/datos

netbsd-nuc# df -h
Filesystem     Size   Used  Avail %Cap Mounted on
/dev/dk4       192G    96G    87G  53% /
tmpfs          4.0G     0B   4.0G   0% /tmp
kernfs         1.0K   1.0K     0B 100% /kern
ptyfs          1.0K   1.0K     0B 100% /dev/pts
procfs         4.0K   4.0K     0B 100% /proc
tmpfs          4.0G     0B   4.0G   0% /var/shm
/dev/sd0e      1.8T   261G   1.4T  15% /mnt/datos

netbsd-nuc# mount -v
/dev/dk4 on / type ffs (local, root file system, fsid: 0xa804/0x78b, reads: sync 45434 async 0, writes: sync 200 async 293)
tmpfs on /tmp type tmpfs (local, fsid: 0xab01/0x69ab, reads: sync 0 async 0, writes: sync 0 async 0)
kernfs on /kern type kernfs (local, fsid: 0x8b02/0x1d28b, reads: sync 0 async 0, writes: sync 0 async 0)
ptyfs on /dev/pts type ptyfs (local, fsid: 0x7b03/0x6b7b, reads: sync 0 async 0, writes: sync 0 async 0)
procfs on /proc type procfs (local, fsid: 0x1b04/0x1ae1b, reads: sync 0 async 0, writes: sync 0 async 0)
tmpfs on /var/shm type tmpfs (local, fsid: 0xab05/0x69ab, reads: sync 0 async 0, writes: sync 0 async 0)
/dev/sd0e on /mnt/datos type ext2fs (local, fsid: 0x404/0x1f3cb, reads: sync 1 async 0, writes: sync 118 async 0)

netbsd-nuc# umount /dev/sd0e

netbsd-nuc# rump_ext2fs /dev/sd0e /mnt/datos
[   1.0000000] entropy: ready

netbsd-nuc# df -h
Filesystem     Size   Used  Avail %Cap Mounted on
/dev/dk4       192G    96G    87G  53% /
tmpfs          4.0G     0B   4.0G   0% /tmp
kernfs         1.0K   1.0K     0B 100% /kern
ptyfs          1.0K   1.0K     0B 100% /dev/pts
procfs         4.0K   4.0K     0B 100% /proc
tmpfs          4.0G     0B   4.0G   0% /var/shm
/dev/sd0e        0B     0B     0B 100% /mnt/datos

netbsd-nuc# mount -v
/dev/dk4 on / type ffs (local, root file system, fsid: 0xa804/0x78b, reads: sync 45576 async 0, writes: sync 200 async 308)
tmpfs on /tmp type tmpfs (local, fsid: 0xab01/0x69ab, reads: sync 0 async 0, writes: sync 0 async 0)
kernfs on /kern type kernfs (local, fsid: 0x8b02/0x1d28b, reads: sync 0 async 0, writes: sync 0 async 0)
ptyfs on /dev/pts type ptyfs (local, fsid: 0x7b03/0x6b7b, reads: sync 0 async 0, writes: sync 0 async 0)
procfs on /proc type procfs (local, fsid: 0x1b04/0x1ae1b, reads: sync 0 async 0, writes: sync 0 async 0)
tmpfs on /var/shm type tmpfs (local, fsid: 0xab05/0x69ab, reads: sync 0 async 0, writes: sync 0 async 0)
/dev/sd0e on /mnt/datos type puffs|p2k|ext2fs (fsid: 0xcb07/0x6acb, reads: sync 0 async 0, writes: sync 0 async 0)
netbsd-nuc#


>How-To-Repeat:
just mount the filesystem rump_ext2fs and "df -h" command.
>Fix:
yes please