>Number:         35112
>Category:       kern
>Synopsis:       tmpfs doesn't play well with unionfs
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Nov 24 19:05:00 +0000 2006
>Originator:     Martin S. Weber
>Release:        NetBSD -current as of 2006-11-21
>Organization:
	
>Environment:
	
	
System: NetBSD circe.entropie.net 4.99.3 NetBSD 4.99.3 (GENERIC.MP) #0: Sat Nov 11 23:41:58 CET 2006 root@circe.entropie.net:/src/obj/sys/arch/i386/compile/GENERIC.MP i386
Architecture: i386
Machine: i386
>Description:

tmpfs is obviously not a valid target for union mount storage areas.
tmpfs shall be the successor of mfs, which is capable of holding the
storage areas of union mounts.

If you try to mount_union into a tmpfs, All you get is "Operation not supported".

As tmpfs shall replace mfs iiuc, tmpfs imo should be capable of holding
union mount storage areas.

	
>How-To-Repeat:

	mkdir banzai mnt1 memory
	dd if=/dev/zero of=banzai/ayaken bs=1m count=1
	makefs banzai.fs banzai

	vnconfig vnd0 banzai.fs
	mount -r /dev/vnd0a mnt1

	mount -t mfs -o,-s=1m swap memory
	mkdir memory/storage
	mount -t union memory/storage mnt1
	touch mnt1/yo ;# works fine, "yo" lies in "memory/storage" now.

	mount -t tmpfs -o,-s=1m swap memory
	mkdir memory/storage
	mount -t union memory/storage mnt1
	mount_union: "memory/storage" is a relative path.
	mount_union: using ".../memory/storage" instead.
	mount_union: .../memory/storage on .../mnt1: Operation not supported

	
>Fix:
	dunno.
	

>Unformatted: