[gparted] Support changing the UUID of a btrfs file system (#751337)

[Curtis Gedak <gedakc src gnome org>]

commit 8308ee6051b329284cd16ae66ad37699c4b7130b
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Fri Jun 19 13:02:32 2015 +0100

    Support changing the UUID of a btrfs file system (#751337)
    
    Btrfs-progs 4.1, released June 2015, includes support for changing the
    UUID of a btrfs file system using the btrfstune command.  Check for
    availability by looking for the -u option in the btrfstune help output.
    Use btrfstune like this:
    
        # umount /dev/sdb1
        # btrfstune -f -u /dev/sdb1
        Current fsid: e7ad5dba-d721-4f99-990b-1ba2901c8ad2
        New fsid: 231563d9-e173-410d-b1da-d34c4319a423
        Set superblock flag CHANGING_FSID
        Change fsid in extents
        Change fsid on devices
        Clear superblock flag CHANGING_FSID
        Fsid change finished
        # echo $?
        0
    
    Bug 751337 - btrfstune in btrfs-progs 4.1 supports changing the file
                 system UUID

 include/btrfs.h |    1 +
 src/btrfs.cc    |   12 ++++++++++++
 2 files changed, 13 insertions(+), 0 deletions(-)
---
diff --git a/include/btrfs.h b/include/btrfs.h
index ce76936..5a69d66 100644
--- a/include/btrfs.h
+++ b/include/btrfs.h
@@ -39,6 +39,7 @@ public:
        void read_label( Partition & partition ) ;
        bool write_label( const Partition & partition, OperationDetail & operationdetail ) ;
        void read_uuid( Partition & partition ) ;
+       bool write_uuid( const Partition & partition, OperationDetail & operationdetail );
        bool create( const Partition & new_partition, OperationDetail & operationdetail ) ;
        bool resize( const Partition & partition_new, OperationDetail & operationdetail, bool fill_partition 
= false ) ;
        bool check_repair( const Partition & partition, OperationDetail & operationdetail ) ;
diff --git a/src/btrfs.cc b/src/btrfs.cc
index b3f141f..a1fee53 100644
--- a/src/btrfs.cc
+++ b/src/btrfs.cc
@@ -107,6 +107,13 @@ FS btrfs::get_filesystem_support()
                }
        }
 
+       if ( ! Glib::find_program_in_path( "btrfstune" ).empty() )
+       {
+               Utils::execute_command( "btrfstune --help", output, error, true );
+               if ( Utils::regexp_label( error, "^[[:blank:]]*(-u)[[:blank:]]" ) == "-u" )
+                       fs.write_uuid = FS::EXTERNAL;
+       }
+
        if ( fs .check )
        {
                fs .copy = GParted::FS::GPARTED ;
@@ -422,6 +429,11 @@ void btrfs::read_uuid( Partition & partition )
        }
 }
 
+bool btrfs::write_uuid( const Partition & partition, OperationDetail & operationdetail )
+{
+       return ! execute_command( "btrfstune -f -u " + partition.get_path(), operationdetail );
+}
+
 void btrfs::clear_cache()
 {
        btrfs_device_cache .clear() ;