Re: [pve-devel] [PATCH storage] btrfs: check for btrfs in on_add_hook and activate

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

On Thu, Jun 24, 2021 at 09:56:58AM +0200, Fabian Grünbichler wrote:
> On June 24, 2021 9:29 am, Wolfgang Bumiller wrote:
> > Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
> > ---
> >  PVE/Storage/BTRFSPlugin.pm | 30 ++++++++++++++++++++++++++++++
> >  1 file changed, 30 insertions(+)
> > 
> > diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
> > index 133edc6..0e111a0 100644
> > --- a/PVE/Storage/BTRFSPlugin.pm
> > +++ b/PVE/Storage/BTRFSPlugin.pm
> > @@ -20,6 +20,7 @@ use constant {
> >      FS_NOCOW_FL => 0x00800000,
> >      FS_IOC_GETFLAGS => 0x40086602,
> >      FS_IOC_SETFLAGS => 0x80086601,
> > +    BTRFS_MAGIC => 0x9123683e,
> >  };
> >  
> >  # Configuration (similar to DirPlugin)
> > @@ -89,8 +90,29 @@ sub check_config {
> >      return PVE::Storage::DirPlugin::check_config($self, $sectionId, $config, $create, $skipSchemaCheck);
> >  }
> >  
> > +my sub getfsmagic($) {
> > +    my ($path) = @_;
> > +    # The field type sizes in `struct statfs` are defined in a rather annoying way, and we only
> > +    # need the first field, which is a `long` for our supported platforms.
> > +    # Should be moved to pve-rs, so this can be the problem of the `libc` crate ;-)
> > +    # Just round up and extract what we need:
> > +    my $buf = pack('x160');
> > +    if (0 != syscall(&PVE::Syscall::SYS_statfs, $path, $buf)) {
> > +	die "statfs on '$path' failed - $!\n";
> > +    }
> > +
> > +    return unpack('L!', $buf);
> > +}
> > +
> > +my sub assert_btrfs($) {
> > +    my ($path) = @_;
> > +    die "'$path' is not a btrfs file system\n"
> > +	if getfsmagic($path) != BTRFS_MAGIC;
> > +}
> > +
> >  sub activate_storage {
> >      my ($class, $storeid, $scfg, $cache) = @_;
> > +    assert_btrfs($scfg->{path});
> >      return PVE::Storage::DirPlugin::activate_storage($class, $storeid, $scfg, $cache);
> 
> shouldn't this be the other way round? first check for things like 
> is_mountpoint, then whether btrfs is there.. makes for less confusing 
> error message at least..

ack, sending v2

> 
> >  }
> >  
> > @@ -179,6 +201,14 @@ sub btrfs_cmd {
> >      return $msg;
> >  }
> >  
> > +sub on_add_hook {
> > +    my ($class, $storeid, $scfg, %param) = @_;
> > +
> > +    assert_btrfs($scfg->{path});
> 
> not needed - adding a new storage calls activate_storage if the storage 
> is enabled..

removing in v2