mount: sshfs problem with "defaults" option after 2.39 upgrade

[Quentin Rameau <quinq@fifth.space>]

Hi,

I just updated util-linux to 2.39 from 2.38.1 (on Alpine Linux),
and new mount triggers an error for an old sshfs fstab mount entry,
that was working until now.

The line in question is:

user@host:path /media/ssh/path sshfs defaults,nosuid,nodev,noexec,noatime,noauto,_netdev,user,idmap=user,allow_other,rec 0 0

and fails with:

$ mount /media/ssh/path
fuse: unknown option(s): `-o defaults'

I can see in the trace that "defaults" is actually passed to the helper

30906 execve("/sbin/mount.sshfs", ["/sbin/mount.sshfs", "user@host:path", "/media/ssh/path", "-o", "rw,defaults,noatime,_netdev,...", <truncated here>

And running it with LIBMOUNT_DEBUG=all shows

30933: libmount:   UPDATE: 30933: libmount:       FS: synced: vfs: 'rw,noatime,nodev,nosuid,noexec' fs: 'idmap=user,allow_other,reconnect' user: 'defaults,noauto,_netdev,, optstr: 'rw,defaults,noatime,noauto,_netdev,user=quinq,nodev,nosuid,noexec,allow_other,reconnect'
[...]
optstr: rw,defaults,noatime,noauto,_netdev,nodev,nosuid,noexec,idmap=user,allow_other,reconnect
VFS-optstr: rw,noatime,nodev,nosuid,noexec
FS-opstr: idmap=user,allow_other,reconnect
user-optstr: defaults,noauto,_netdev

The "defaults" option is stripped from the analog traces with mount 2.38.1