Re: wapbl file system on logical volume

[Christof Meerwald <cmeerw%cmeerw.org@localhost>]

On Sun, Sep 28, 2025 at 12:45:21PM +0200, Christof Meerwald wrote:
> On Sun, Sep 28, 2025 at 10:50:08AM +0200, Matthias Petermann wrote:
> > Hello Christof,
> > 
> > On Sat Sep 27, 2025 at 9:12 PM CEST, Christof Meerwald wrote:
> > > Just thought I'd give LVM a try (on 11.0_BETA). Everything seemed to
> > > be fine until I tried to mount a filesystem with the "log" option:
> > >
> > > mount -o log /dev/mapper/M247--X10E--9N--vg-netbsd--test /mnt/test/
> > > mount_ffs: /dev/mapper/M247--X10E--9N--vg-netbsd--test on /mnt/test: Inappropriate ioctl for device
> > >
> > > but without the log option it's fine:
> > >
> > > mount /dev/mapper/M247--X10E--9N--vg-netbsd--test /mnt/test/
> > 
> > Not sure if this helps, but as I am also interested in exactly
> > this setup you are using here let me add some data points:
> > 
> > ```
> > ~ [ sudo lvm lvs                                                  ] 10:40 vorm.
> >   LV   VG   Attr   LSize   Origin Snap%  Move Log Copy%  Convert
> >   data vg0  -wi-a- 200,00g                                      
> >   home vg0  -wi-a- 200,00g  
> > ```
> > 
> > ```
> > ~ [ cat /etc/fstab
> > ...                                                ] 10:38 vorm.
> > /dev/mapper/vg0-data	/u	ffs	rw,log	0	0
> > /dev/mapper/vg0-home	/h	ffs	rw,log	0	0
> > ```
> > 	
> > ```
> > ~ [ mount                                                         ] 10:39 vorm.
> > ...
> > /dev/mapper/vg0-data on /u type ffs (log, local)
> > /dev/mapper/vg0-home on /h type ffs (log, local)
> > ```
> > 
> > ```
> > ~ [ uname -a                                                      ] 10:40 vorm.
> > NetBSD x230.lan 10.1 NetBSD 10.1 (GENERIC) #0: Mon Dec 16 13:08:11 UTC 2024  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
> > ```
> > 
> > Summary: in NetBSD 10.1 this works.
> > 
> > How did you create the filesystem in the LV? newfs -O2
> > is required I think to use wapbl.
> 
> Was actually using "newfs -O2ea" (but "newfs -O2" makes no difference).
> 
> I have now been able to test this in a small test VM.
> 
> As you say, with NetBSD 10.1 it works fine, but with a NetBSD
> 11.0_BETA kernel (Wed Sep 24 12:39:13 UTC 2025) I get the
> "Inappropriate ioctl for device" error when trying to mount with "-o
> log" (that's with a newly created filesystem).

Ok, I think have figured it out now.

https://cvsweb.netbsd.org/bsdweb.cgi/src/sys/dev/dm/dm_ioctl.c.diff?r1=1.56;r2=1.57;f=h

with this change (the second part of it) it now fails on NetBSD
11.0_BETA, but I think the change is actually good.

Where it actually fails is in "getdisksize": this does a
DIOCGWEDGEINFO and then a disk_find on dkw.dkw_parent.

I think the issue is in the handling of DIOCGWEDGEINFO in
dev/dm/device-mapper.c where it sets dkw->dkw_parent to dmv->name.
Should that maybe also use device_xname(dmv->devt)? (and what should
dkw->device_name be set to there?)


Christof

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