daemon: Implement set-label for XFS and fix it for btrfs (RHBZ#986875).

Implement 'set-label' for XFS filesystems.

Fix the call for btrfs.  Previous
commit d5817537fa added some bogus
documentation implying this call would work for btrfs, but it did
not.

Add tests.

Makefile.am

@@ -46,6 +46,7 @@ SUBDIRS += tests/md
 SUBDIRS += tests/selinux
 SUBDIRS += tests/ntfsclone
 SUBDIRS += tests/btrfs
+SUBDIRS += tests/xfs
 SUBDIRS += tests/charsets
 SUBDIRS += tests/xml
 SUBDIRS += tests/mount-local

configure.ac

@@ -1676,6 +1676,7 @@ AC_CONFIG_FILES([Makefile
                  tests/selinux/Makefile
                  tests/syslinux/Makefile
                  tests/tmpdirs/Makefile
+                 tests/xfs/Makefile
                  tests/xml/Makefile
                  tools/Makefile])
 AC_OUTPUT

daemon/labels.c

@@ -27,8 +27,10 @@
 #include "actions.h"
 #include "optgroups.h"
 
+GUESTFSD_EXT_CMD(str_btrfs, btrfs);
 GUESTFSD_EXT_CMD(str_e2label, e2label);
 GUESTFSD_EXT_CMD(str_ntfslabel, ntfslabel);
+GUESTFSD_EXT_CMD(str_xfs_admin, xfs_admin);
 
 static int
 e2label (const char *device, const char *label)
@@ -70,6 +72,45 @@ ntfslabel (const char *device, const char *label)
   return 0;
 }
 
+static int
+xfslabel (const char *device, const char *label)
+{
+  int r;
+  CLEANUP_FREE char *err = NULL;
+
+  /* Don't allow the special value "---".  If people want to clear
+   * the label we'll have to add another call to do that.
+   */
+  if (STREQ (label, "---")) {
+    reply_with_error ("xfs: invalid new label");
+    return -1;
+  }
+
+  r = command (NULL, &err, str_xfs_admin, "-L", label, device, NULL);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    return -1;
+  }
+
+  return 0;
+}
+
+static int
+btrfslabel (const char *device, const char *label)
+{
+  int r;
+  CLEANUP_FREE char *err = NULL;
+
+  r = command (NULL, &err, str_btrfs, "filesystem", "label",
+               device, label, NULL);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    return -1;
+  }
+
+  return 0;
+}
+
 int
 do_set_label (const mountable_t *mountable, const char *label)
 {
@@ -86,6 +127,12 @@ do_set_label (const mountable_t *mountable, const char *label)
   else if (STREQ (vfs_type, "ntfs"))
     r = ntfslabel (mountable->device, label);
 
+  else if (STREQ (vfs_type, "xfs"))
+    r = xfslabel (mountable->device, label);
+
+  else if (STREQ (vfs_type, "btrfs"))
+    r = btrfslabel (mountable->device, label);
+
   else {
     reply_with_error ("don't know how to set the label for '%s' filesystems",
                       vfs_type);

generator/actions.ml

@@ -9509,12 +9509,29 @@ Set the filesystem label on C<mountable> to C<label>.
 Only some filesystem types support labels, and libguestfs supports
 setting labels on only a subset of these.
 
-On ext2/3/4 filesystems, labels are limited to 16 bytes.
+=over 4
 
-On NTFS filesystems, labels are limited to 128 unicode characters.
+=item ext2, ext3, ext4
 
-Setting the label on a btrfs subvolume will set the label on its parent
-filesystem.
+Labels are limited to 16 bytes.
+
+=item NTFS
+
+Labels are limited to 128 unicode characters.
+
+=item XFS
+
+The label is limited to 12 bytes.  The filesystem must not
+be mounted when trying to set the label.
+
+=item btrfs
+
+The label is limited to 256 bytes and some characters are
+not allowed.  Setting the label on a btrfs subvolume will set the
+label on its parent filesystem.  The filesystem must not be mounted
+when trying to set the label.
+
+=back
 
 To read the label on a filesystem, call C<guestfs_vfs_label>." };
 

tests/btrfs/Makefile.am

@@ -18,6 +18,7 @@
 include $(top_srcdir)/subdir-rules.mk
 
 TESTS = \
+	test-btrfs-misc.pl \
 	test-btrfs-devices.sh \
 	test-btrfs-subvolume-default.pl
 

tests/btrfs/test-btrfs-misc.pl

@@ -0,0 +1,51 @@
+#!/usr/bin/perl
+# libguestfs
+# Copyright (C) 2013 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# Miscellaneous btrfs features.
+
+use strict;
+use warnings;
+
+use Sys::Guestfs;
+
+# Allow the test to be skipped since btrfs is often broken.
+exit 77 if $ENV{SKIP_TEST_BTRFS_MISC_PL};
+
+my $g = Sys::Guestfs->new ();
+
+$g->add_drive_scratch (1024*1024*1024);
+$g->launch ();
+
+# If btrfs is not available, bail.
+unless ($g->feature_available (["btrfs"])) {
+    warn "$0: skipping test because btrfs is not available\n";
+    exit 77;
+}
+
+$g->part_disk ("/dev/sda", "mbr");
+
+$g->mkfs_btrfs (["/dev/sda1"]);
+
+# Setting label.
+$g->set_label ("/dev/sda1", "newlabel");
+my $label = $g->vfs_label ("/dev/sda1");
+die "unexpected label: expecting 'newlabel' but got '$label'"
+    unless $label eq "newlabel";
+
+$g->shutdown ();
+$g->close ();

tests/xfs/Makefile.am

@@ -0,0 +1,26 @@
+# libguestfs
+# Copyright (C) 2013 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+include $(top_srcdir)/subdir-rules.mk
+
+TESTS = \
+	test-xfs-misc.pl
+
+TESTS_ENVIRONMENT = $(top_builddir)/run --test
+
+EXTRA_DIST = \
+	$(TESTS)

tests/xfs/test-xfs-misc.pl

@@ -0,0 +1,50 @@
+#!/usr/bin/perl
+# libguestfs
+# Copyright (C) 2013 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# Miscellaneous xfs features.
+
+use strict;
+use warnings;
+
+use Sys::Guestfs;
+
+exit 77 if $ENV{SKIP_TEST_XFS_MISC_PL};
+
+my $g = Sys::Guestfs->new ();
+
+$g->add_drive_scratch (1024*1024*1024);
+$g->launch ();
+
+# If xfs is not available, bail.
+unless ($g->feature_available (["xfs"])) {
+    warn "$0: skipping test because xfs is not available\n";
+    exit 77;
+}
+
+$g->part_disk ("/dev/sda", "mbr");
+
+$g->mkfs ("xfs", "/dev/sda1");
+
+# Setting label.
+$g->set_label ("/dev/sda1", "newlabel");
+my $label = $g->vfs_label ("/dev/sda1");
+die "unexpected label: expecting 'newlabel' but got '$label'"
+    unless $label eq "newlabel";
+
+$g->shutdown ();
+$g->close ();