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

[Pino Toscano]

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
 }

> > > +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