[Libguestfs] [PATCH v3.1 1/9] uuid: add support to change uuid of btrfs partition

[Chen, Hanxiao]

> -----Original Message-----
> From: libguestfs-bounces at redhat.com [mailto:libguestfs-bounces at redhat.com] On
> Behalf Of Pino Toscano
> Sent: Tuesday, June 30, 2015 12:07 AM
> To: libguestfs at redhat.com
> Subject: Re: [Libguestfs] [PATCH v3.1 1/9] uuid: add support to change uuid of btrfs
> partition
> 
> In data lunedì 29 giugno 2015 02:36:57, Chen, Hanxiao ha scritto:
> >
> > > -----Original Message-----
> > > From: libguestfs-bounces at redhat.com [mailto:libguestfs-bounces at redhat.com] On
> > > Behalf Of Pino Toscano
> > > Sent: Friday, June 26, 2015 8:12 PM
> > > To: libguestfs at redhat.com
> > > Subject: Re: [Libguestfs] [PATCH v3.1 1/9] uuid: add support to change uuid
> of btrfs
> > > partition
> > >
> > > In data venerdì 26 giugno 2015 17:35:36, Chen Hanxiao ha scritto:
> > > > btrfs-progs v4.1 add support to change uuid of btrfs fs.
> > > >
> > > > Signed-off-by: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>
> > > > ---
> > > > v3.1: fix a typo
> > > > v3: set errno as ENOTSUP when btrfstune -u is not available
> > > > v2: put btrfs operation back to daemon/btrfs.c
> > > >     move tests to tests/btrfs
> > > >
> > > >  daemon/btrfs.c                 | 60
> ++++++++++++++++++++++++++++++++++++++++++
> > > >  daemon/daemon.h                |  1 +
> > > >  daemon/uuids.c                 |  6 ++---
> > > >  tests/btrfs/test-btrfs-misc.pl | 17 ++++++++++++
> > > >  4 files changed, 80 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/daemon/btrfs.c b/daemon/btrfs.c
> > > > index 20e5e6b..a69c512 100644
> > > > --- a/daemon/btrfs.c
> > > > +++ b/daemon/btrfs.c
> > > > @@ -790,6 +790,44 @@ do_btrfs_device_delete (char *const *devices, const char
> > > *fs)
> > > >    return 0;
> > > >  }
> > > >
> > > > +
> > > > +/* btrfstune command add two new options
> > > > + * -U UUID      change fsid to UUID
> > > > + * -u           change fsid, use a random one
> > > > + * since v4.1
> > > > + * We could check wheter 'btrfstune' support
> > > > + * '-u' and '-U UUID' option by checking the output of
> > > > + * 'btrfstune' command.
> > > > + */
> > > > +static int
> > > > +test_btrfstune_uuid_opt (void)
> > > > +{
> > > > +  static int result = -1;
> > > > +  if (result != -1)
> > > > +    return result;
> > > > +
> > > > +  CLEANUP_FREE char *err = NULL;
> > > > +
> > > > +  int r = commandr (NULL, &err, str_btrfstune, NULL);
> > > > +
> > > > +  if (r == -1) {
> > > > +    reply_with_error ("btrfstune: %s", err);
> > > > +    return -1;
> > > > +  }
> > > > +
> > > > +  /* FIXME currently btrfstune do not support '--help'.
> > >
> > > So --help should be passed anyway to the btrfstune invocation, so with
> > > newer versions hopefully there will not be complaints about it anymore.
> >
> > Fine.
> >
> > >
> > [snip]
> > > > diff --git a/tests/btrfs/test-btrfs-misc.pl b/tests/btrfs/test-btrfs-misc.pl
> > > > index 2fe7c59..b47caab 100755
> > > > --- a/tests/btrfs/test-btrfs-misc.pl
> > > > +++ b/tests/btrfs/test-btrfs-misc.pl
> > > > @@ -20,6 +20,7 @@
> > > >
> > > >  use strict;
> > > >  use warnings;
> > > > +use Errno;
> > > >
> > > >  use Sys::Guestfs;
> > > >
> > > > @@ -47,5 +48,21 @@ my $label = $g->vfs_label ("/dev/sda1");
> > > >  die "unexpected label: expecting 'newlabel' but got '$label'"
> > > >      unless $label eq "newlabel";
> > > >
> > > > +# Setting btrfs UUID
> > > > +eval {
> > > > +    $g->set_uuid ("/dev/sda1", "12345678-1234-1234-1234-123456789012");
> > > > +};
> > > > +# FIXME: ignore ESRCH
> > >
> > > What is ESRCH about?
> >
> > The problem is every time I got a ESRCH here.
> > I have no idea about this.
> >
> > Can we just ignore it by:
> > } elsif ($err == Errno::ESRCH()) {
> >     ;
> > } else {
> >    die $@;
> > }
> 
> No, please investigate why you are getting such errno.
> 
> One guess is that a leftover from a failing operation, and that
> set_uuid actually succeeded. In that case, checking first for $@ might
> do the trick:
> 
>  eval {
>      ...
>  }
>  if ($@) {
>      # failed, check last_errno
>  } else {
>      # good, compare with vfs_uuid
>  }
> 

Thanks for your hints.

v4 will come soon.

Regards,
- Chen

> > > > +my $err = $g->last_errno ();
> > > > +
> > > > +if ($err == 0) {
> > > > +    my $uuid = $g->vfs_uuid ("/dev/sda1");
> > > > +    die "unexpected uuid expecting
> > > > +     '12345678-1234-1234-1234-123456789012' but got '$uuid'"
> > > > +    unless $uuid eq "12345678-1234-1234-1234-123456789012";
> > > > +} elsif ($err == Errno::ENOTSUP()) {
> > > > +    warn "$0: skipping test for btrfs UUID change feature is not available\n";
> > > > +}
> > >
> > > IIRC 'warn' prints the newline at the end already.
> > >
> > > This is missing to check when $err is a valid error.
> > >
> >
> > Can we just:
> > } else {
> >    die $@;
> > }
> 
> Yes, that should be fine.
> 
> Thanks,
> --
> Pino Toscano
> 
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