no access with 9p qemu-kvm filesystem

[Ulli Horlacher]

I have a KVM host and a guest (VM), both with Ubuntu 14,04
I want to mount a filesystem from the host by the VM via 9p.
When using the setup described in
http://www.linux-kvm.org/page/9p_virtio
I can mount the host directory:

root@flupp:/# mount | grep /spool_
/spool_mapped on /spool_mapped type 9p (rw,trans=virtio,version=9p2000.L)
/spool_passthrough on /spool_passthrough type 9p (rw,trans=virtio,version=9p2000.L)
/spool_squash on /spool_squash type 9p (rw,trans=virtio,version=9p2000.L)

but when I try to access files I get errors:

root@flupp:/# ls -ld /spool_*/xx*
ls: cannot read symbolic link /spool_mapped/xx2: Too many levels of symbolic links
drwx------ 1 fex fex 4 May 28 18:28 /spool_mapped/xx1
lrwxrwxrwx 1 fex fex 3 May 28 13:56 /spool_mapped/xx2
drwx------ 1 fex fex 4 May 28 18:28 /spool_passthrough/xx1
lrwxrwxrwx 1 fex fex 3 May 28 13:56 /spool_passthrough/xx2 -> xx1
drwx------ 1 fex fex 4 May 28 18:28 /spool_squash/xx1
lrwxrwxrwx 1 fex fex 3 May 28 13:56 /spool_squash/xx2 -> xx1

root@flupp:/# ls -l /spool_*/xx1
ls: cannot open directory /spool_mapped/xx1: Permission denied
ls: cannot open directory /spool_passthrough/xx1: Permission denied
ls: cannot open directory /spool_squash/xx1: Permission denied

root@flupp:/# id
uid=0(root) gid=0(root) groups=0(root)

When I use nfs instead of 9p everything looks ok:

root@flupp:/# mount | grep spool.*nfs
kvmhost:/data/fex/spool on /spool type nfs (rw,relatime,nfsvers=3,proto=udp,addr=192.168.254.1)

root@flupp:/spool# ls -ld /spool/xx1/*
-rw------- 1 fex fex 77096 May 28 13:56 /spool/xx1/xx

root@flupp:/spool# wc /spool/xx1/xx
 1252 6264 77096 /spool/xx1/xx

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1460629/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]