[sheepdog-users] sheepfs: cannot detach / error failed to create sheepfs layout

[Liu Yuan]

On Thu, Sep 12, 2013 at 05:53:26AM +0200, Gerald Richter - ECOS wrote:
> > >
> > > That was what I was expecting, but a simple test shows:
> > >
> > > #echo vm-1201-disk-1 > /mnt/vdi/mount #echo vm-1201-disk-1 >
> > > /mnt/vdi/unmount
> > > -bash: echo: write error: Invalid argument
> > >
> 
> Syslog:
> Sep 12 05:21:33 srvvm4 sheepfs[169962]: volume_sync_and_delete(499)
> Sep 12 05:21:33 srvvm4 sheepfs[169962]: failed to flush vdi fb24b0
> 
> I have done a "dog vdi cache flush vm-1201-disk-1" afterwards and all changes I have made in this image seems to be correctly written.

We don't need any manual command for sheepfs. It is quit self-contained.
echo 'xxx' > sheepfs/vdi/unmount will flush the cache if any (this cache means 
object cache enabled in the sheep to which sheepfs connect)

> > > On my second node I get the following error message:
> > >
> > > #sheepfs /mnt
> > > failed to create sheepfs layout
> > >
> 
> Syslog:
> Sep 12 05:26:08 srvvm1 sheepfs: shadow_file_setxattr(102)
> Sep 12 05:26:08 srvvm1 sheepfs: Operation not supported
> 
> So I mounted the sheepfs on different volume, which was mount with user_xattr and it worked, but afterwards I also able to mount on the initial directory also, which was not mounted with xattr.
> 
> Doing some more test I found, that sheepfs creates a directry .sheepfs in the current directory, which needs to be mounted which xattr support. So running this command in a directory which does not have xattr support will not work, regardless of the directory that is actually mounted.
> 
> I don't have an idea why the .sheepfs directory is needed, but I think it is not a good idea to create it in the current working directory, at least there should be some option and/or environment variable to change the location. Also it would be very helpful to have the error message on stderr instead of the syslog.
> 
> Anyway, after understanding how it works, it did what it should and I was able to modify my image before/without booting it. That's great!

Hmm, I'll add a xattr support check in the init of sheepfs.

Thanks
Yuan