Display usage of encrypted file systems (#760080)

There is already the set of methods in the Partition class to report the
file system usage.  Virtualise them and provide PartitionLUKS specific
implementations to calculate the usage of a file system wrapped in LUKS
encryption.

See the ascii art and comment in PartitionLUKS.cc for the details of
those calculations.

Bug 760080 - Implement read-only LUKS support
This commit is contained in:
Mike Fleetwood 2015-12-28 13:47:12 +00:00 committed by Curtis Gedak
parent 38a790d745
commit cb24aa4be1
3 changed files with 114 additions and 5 deletions

View File

@ -82,11 +82,11 @@ public:
bool busy );
void set_sector_usage( Sector sectors_fs_size, Sector sectors_fs_unused ) ;
bool sector_usage_known() const ;
Sector estimated_min_size() const ;
Sector get_sectors_used() const ;
Sector get_sectors_unused() const ;
Sector get_sectors_unallocated() const ;
virtual bool sector_usage_known() const;
virtual Sector estimated_min_size() const;
virtual Sector get_sectors_used() const;
virtual Sector get_sectors_unused() const;
virtual Sector get_sectors_unallocated() const;
void get_usage_triple( int imax, int & i1, int & i2, int & i3 ) const ;
void Set_Unallocated( const Glib::ustring & device_path,

View File

@ -34,6 +34,11 @@ public:
Partition & get_encrypted() { return encrypted; };
const Partition & get_encrypted() const { return encrypted; };
virtual bool sector_usage_known() const;
virtual Sector estimated_min_size() const;
virtual Sector get_sectors_used() const;
virtual Sector get_sectors_unused() const;
virtual Sector get_sectors_unallocated() const;
virtual Glib::ustring get_filesystem_label() const;
private:

View File

@ -37,6 +37,110 @@ PartitionLUKS * PartitionLUKS::clone() const
return new PartitionLUKS( *this );
}
bool PartitionLUKS::sector_usage_known() const
{
if ( busy )
// For an open dm-crypt mapping the usage of both the LUKS and encrypted
// file system must be known.
return Partition::sector_usage_known() && encrypted.sector_usage_known();
return Partition::sector_usage_known();
}
// An encrypted partition is laid out, and usage figures calculated like this:
//
// Partition
// |<---------------------------------------->| <- this PartitionLUKS object
// LUKS LUKS
// Header Mapping
// |<--->||<----------------------->| <- encrypted Partition object member
// 1111111111111111111111111111111111uuuuuuuuuu <- this->sectors_{used,unused,unallocated}
// Encrypted file system
// |<----------------->|
// 111111111111110000000uuuuuu <- encrypted.sectors_{used,unused,unallocated}
// ^ ^
// | `------------- encrypted.sector_end
// `--------------------------------------- encrypted.sector_start (== size of LUKS header)
// 1111111111111111111110000000uuuuuuuuuuuuuuuu <- Overall usage figures as used in the following
// usage related methods.
// Legend:
// 1 - used sectors
// 0 - unused sectors
// u - unallocated sectors
//
// Calculations:
// total_used = LUKS Header size + Encrypted file system used
// = encrypted.sector_start + encrypted.sectors_used
// total_unallocated = LUKS unallocated + Encrypted file system unallocated
// = this->sectors_unallocated + encrypted_unallocated
// total_unused = LUKS unused + Encrypted file system unused
// = 0 + encrypted.sectors_unused
//
// By definition LUKS unused is 0 (See luks::set_used_sectors()).
// Return estimated minimum size to which the partition can be resized.
// See Partition::estimated_min_size() for unallocated threshold reasoning.
Sector PartitionLUKS::estimated_min_size() const
{
if ( busy )
{
// For an open dm-crypt mapping work with above described totals.
if ( sectors_used >= 0 && encrypted.sectors_used >= 0 )
{
Sector total_used = encrypted.sector_start + encrypted.sectors_used;
Sector total_unallocated = sectors_unallocated + encrypted.sectors_unallocated;
return total_used + std::min( total_unallocated, significant_threshold );
}
return -1;
}
return Partition::estimated_min_size();
}
// Return user displayable used sectors.
// See Partition::get_sectors_used() for unallocated threshold reasoning.
Sector PartitionLUKS::get_sectors_used() const
{
if ( busy )
{
// For an open dm-crypt mapping work with above described totals.
if ( sectors_used >= 0 && encrypted.sectors_used >= 0 )
{
Sector total_used = encrypted.sector_start + encrypted.sectors_used;
Sector total_unallocated = sectors_unallocated + encrypted.sectors_unallocated;
if ( total_unallocated < significant_threshold )
return total_used + total_unallocated;
else
return total_used;
}
return -1;
}
return Partition::get_sectors_used();
}
// Return user displayable unused sectors.
// See above described totals.
Sector PartitionLUKS::get_sectors_unused() const
{
if ( busy )
return encrypted.get_sectors_unused();
return Partition::get_sectors_unused();
}
// Return user displayable unallocated sectors.
// See Partition::get_sectors_unallocated() for unallocated threshold reasoning.
Sector PartitionLUKS::get_sectors_unallocated() const
{
if ( busy )
{
// For an open dm-crypt mapping work with above described totals.
Sector total_unallocated = sectors_unallocated + encrypted.sectors_unallocated;
if ( total_unallocated < significant_threshold )
return 0;
else
return total_unallocated;
}
return Partition::get_sectors_unallocated();
}
// Return the label of the encrypted file system within, or "" if no open mapping.
Glib::ustring PartitionLUKS::get_filesystem_label() const
{