gparted/include/btrfs.h
Mike Fleetwood 7fc16a1b69 Handle btrfs tools rounding of figures (#499202)
The btrfs programs only provide approximations of file system sizes
because they display figures using binary prefix multipliers to two
decimal places of precision.  E.g. 2.00GB.  For partition sizes where
the contained file system size rounds upwards, GParted will fail to read
the file system usage and report a warning because the file system will
appear to be larger than the partition.

For example, create a 2047 MiB partition containing a btrfs file system
and display its size.

    # btrfs filesystem show
    Label: none  uuid: 92535375-5e76-4a70-896a-8d796a577993
            Total devices 1 FS bytes used 28.00KB
            devid    1 size 2.00GB used 240.62MB path /dev/sda12

The file system size appears to be 2048 MiB, but that is larger than the
partition, hence the issue GParted has.  (Actually uses the btrfs devid
size which is the size of the btrfs file system within the partition in
question).

This issue is new with the fix for Bug #499202 because it queries the
file system sizes for the first time.  The same issue could
theoretically occur previously, but with the used figure (FS bytes
used).  This would have been virtually impossible to trigger because
btrfs file system would have to have been greater than 99% full, but
btrfs has been notorious for early reporting of file system full.

The fix is that if a btrfs file system size appears larger than the
partition size, but the minimum possible size which could have been
rounded to the reported figure is within the partition size use the
smaller partition size instead.  Apply the method to the used figure
too, in case the file system is 100% full.  Also if the btrfs file
system size appears smaller than the partition size, but the maximum
possible size which could have been rounded to the reported figure is
within the partition size use the larger partition size instead to avoid
reporting, presumably false, unallocated space.  Not applied to file
system used figure.

Bug 499202 - gparted does not see the difference if partition size
             differs from filesystem size
2012-06-18 10:24:29 -06:00

54 lines
2.1 KiB
C++

/* Copyright (C) 2009,2010 Luca Bruno <lucab@debian.org>
* Copyright (C) 2010 Curtis Gedak
*
* 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 Library 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef BTRFS_H_
#define BTRFS_H_
#include "../include/FileSystem.h"
namespace GParted
{
class btrfs : public FileSystem
{
public:
FS get_filesystem_support() ;
void set_used_sectors( Partition & partition ) ;
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 move( const Partition & partition_new
, const Partition & partition_old
, OperationDetail & operationdetail
) ;
bool copy( const Glib::ustring & src_part_path,
const Glib::ustring & dest_part_path,
OperationDetail & operationdetail ) ;
bool check_repair( const Partition & partition, OperationDetail & operationdetail ) ;
private:
Byte_Value btrfs_size_to_num( Glib::ustring str, Byte_Value ptn_bytes, bool scale_up ) const ;
gdouble btrfs_size_max_delta( Glib::ustring str ) const ;
gdouble btrfs_size_to_gdouble( Glib::ustring str ) const ;
};
} //GParted
#endif //BTRFS_H_