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partitionmanager
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make snapping rules for start and end of partitions more abstract and begin 

implementing vista's weird snapping rules.

svn path=/trunk/extragear/sysadmin/partitionmanager/; revision=1083886
This commit is contained in:
Volker Lanz 2010-02-02 08:40:24 +00:00
parent c809be064a
commit 896d31e179
1 changed files with 81 additions and 27 deletions
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108
src/core/partitiontable.cpp
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@ -204,6 +204,29 @@ QStringList PartitionTable::flagNames(Flags flags)
return rval;
}
/** @return the sector size to snap the partition start and end to
*/
static quint64 snapSize(const Device& d)
{
return d.partitionTable()->type() == PartitionTable::msdos ? d.cylinderSize() : 2048;
}
static QString snappedFirstString(const Device& d)
{
// Vista wants partitions not only to be snapped to the snapSize but also the last
// digits of the actual sector number are required to be the same, for whatever
// reason. In practice: Partitions always start at a number divisable by
// 2048 AND ending in xxxxxxx2048. There do not seem to be any official docs about
// that, only this: http://support.microsoft.com/kb/923332
// See also: http://www.multibooters.co.uk/partitions.html
return QString::number(snapSize(d));
}
static QString snappedLastString(const Device& d)
{
return QString::number(snapSize(d) - 1);
}
/** Checks if a given Partition on a given Device is snapped to cylinder boundaries.
Will print warning messages to GlobalLog if the Partition's first sector is not snapped and
@ -217,8 +240,8 @@ QStringList PartitionTable::flagNames(Flags flags)
*/
bool PartitionTable::isSnapped(const Device& d, const Partition& p)
{
// only msdos gets snapped -- TODO: add msdos_vista
if (d.partitionTable()->type() != msdos)
// only msdos and msdos_vista get snapped
if (d.partitionTable()->type() != msdos && d.partitionTable()->type() != msdos_vista)
return true;
// don't bother with unallocated space here.
@ -227,7 +250,8 @@ bool PartitionTable::isSnapped(const Device& d, const Partition& p)
qint64 delta = 0;
// There are some special cases for snapping partitions to cylinder boundaries, apparently.
// TODO: verify the following comment and code both for msdos and msdos_vista
// There are some special cases for snapping partitions:
// 1) If an extended partition starts at the beginning of the device (that would be sector 63
// on modern drives, equivalent to sectorsPerTrack() in any case), the first logical partition
// at the beginning of this extended partition starts at 2 * sectorsPerTrack().
@ -235,25 +259,37 @@ bool PartitionTable::isSnapped(const Device& d, const Partition& p)
// 3) Any logical partition is always preceded by the extended partition table entry in the
// sectorsPerTrack() before it, so it's always sectorsPerTrack() "late"
if (p.roles().has(PartitionRole::Logical) && p.firstSector() == 2 * d.sectorsPerTrack())
delta = (p.firstSector() - (2 * d.sectorsPerTrack())) % d.cylinderSize();
delta = (p.firstSector() - (2 * d.sectorsPerTrack())) % snapSize(d);
else if (p.roles().has(PartitionRole::Logical) || p.firstSector() == d.sectorsPerTrack())
delta = (p.firstSector() - d.sectorsPerTrack()) % d.cylinderSize();
delta = (p.firstSector() - d.sectorsPerTrack()) % snapSize(d);
else
delta = p.firstSector() % d.cylinderSize();
delta = p.firstSector() % snapSize(d);
bool rval = true;
if (delta)
{
Log(Log::warning) << i18nc("@info/plain", "Partition <filename>%1</filename> does not start at a cylinder boundary (first sector: %2, modulo: %3).", p.deviceNode(), p.firstSector(), delta);
Log(Log::warning) << i18nc("@info/plain", "Partition <filename>%1</filename> does not start at the recommended boundary (first sector: %2, modulo: %3).", p.deviceNode(), p.firstSector(), delta);
rval = false;
}
delta = (p.lastSector() + 1) % d.cylinderSize();
if (d.partitionTable()->type() == msdos_vista && QString::number(p.firstSector()).right(snappedFirstString(d).length()) != snappedFirstString(d))
{
Log(Log::warning) << i18nc("@info/plain", "First sector %1 of partition <filename>%2</filename> does not end in the digits '%3'.", p.firstSector(), p.deviceNode(), snappedFirstString(d));
rval = false;
}
delta = (p.lastSector() + 1) % snapSize(d);
if (delta)
{
Log(Log::warning) << i18nc("@info/plain", "Partition <filename>%1</filename> does not end at a cylinder boundary (last sector: %2, modulo: %3).", p.deviceNode(), p.lastSector(), delta);
Log(Log::warning) << i18nc("@info/plain", "Partition <filename>%1</filename> does not end at the recommended boundary (last sector: %2, modulo: %3).", p.deviceNode(), p.lastSector(), delta);
rval = false;
}
if (d.partitionTable()->type() == msdos_vista && QString::number(p.lastSector()).right(snappedLastString(d).length()) != snappedLastString(d))
{
Log(Log::warning) << i18nc("@info/plain", "Last sector %1 of partition <filename>%2</filename> does not end in the digits '%3'.", p.lastSector(), p.deviceNode(), snappedLastString(d));
rval = false;
}
@ -304,31 +340,31 @@ static bool canSnapToSector(const Device& d, const Partition& p, qint64 s, const
*/
bool PartitionTable::snap(const Device& d, Partition& p, const Partition* originalPartition)
{
// TODO: implement snapping to 2048-sector-boundaries for msdos_vista
if (d.partitionTable()->type() != msdos)
if (d.partitionTable()->type() != msdos && d.partitionTable()->type() != msdos_vista)
return true;
const qint64 originalLength = p.length();
qint64 delta = 0;
bool lengthIsSnapped = false;
// TODO: verify for msdos and msdos_vista
// This is the same as in isSnapped(), only we additionally have to remember if the
// partition's _length_ is "snapped", so to speak (i.e., evenly divisable by
// the cylinder size)
if (p.roles().has(PartitionRole::Logical) && p.firstSector() == 2 * d.sectorsPerTrack())
{
delta = (p.firstSector() - (2 * d.sectorsPerTrack())) % d.cylinderSize();
lengthIsSnapped = (p.length() + (2 * d.sectorsPerTrack())) % d.cylinderSize() == 0;
delta = (p.firstSector() - (2 * d.sectorsPerTrack())) % snapSize(d);
lengthIsSnapped = (p.length() + (2 * d.sectorsPerTrack())) % snapSize(d) == 0;
}
else if (p.roles().has(PartitionRole::Logical) || p.firstSector() == d.sectorsPerTrack())
{
delta = (p.firstSector() - d.sectorsPerTrack()) % d.cylinderSize();
lengthIsSnapped = (p.length() + d.sectorsPerTrack()) % d.cylinderSize() == 0;
delta = (p.firstSector() - d.sectorsPerTrack()) % snapSize(d);
lengthIsSnapped = (p.length() + d.sectorsPerTrack()) % snapSize(d) == 0;
}
else
{
delta = p.firstSector() % d.cylinderSize();
lengthIsSnapped = p.length() % d.cylinderSize() == 0;
delta = p.firstSector() % snapSize(d);
lengthIsSnapped = p.length() % snapSize(d) == 0;
}
if (delta)
@ -345,6 +381,15 @@ bool PartitionTable::snap(const Device& d, Partition& p, const Partition* origin
// ends up too small. So try to move the start to the front first.
qint64 snappedFirst = p.firstSector() - delta;
if (d.partitionTable()->type() == msdos_vista)
{
while (snappedFirst > 0 && QString::number(snappedFirst).right(snappedFirstString(d).length()) != snappedFirstString(d))
{
// kDebug() << "snappedFirst: " << snappedFirst;
snappedFirst -= snapSize(d);
}
}
// If we're now before the first usable sector, just take the first usable sector. This
// will happen if we're already below cylinder one and snap to the front
if (snappedFirst < d.partitionTable()->firstUsable())
@ -354,13 +399,13 @@ bool PartitionTable::snap(const Device& d, Partition& p, const Partition* origin
if (!canSnapToSector(d, p, snappedFirst, originalPartition))
{
// ... move to the cylinder towards the end of the device ...
snappedFirst = p.firstSector() - delta + d.cylinderSize();
snappedFirst = p.firstSector() - delta + snapSize(d);
// ... and move the end of the partition towards the end, too, if that is possible.
// By doing this, we still try to keep the length >= the original length. If the
// last sector ends up not being on a cylinder boundary by doing so, the code
// below will deal with that.
qint64 numTooShort = d.cylinderSize() - delta;
qint64 numTooShort = snapSize(d) - delta;
if (canSnapToSector(d, p, p.lastSector() + numTooShort, originalPartition))
{
p.setLastSector(p.lastSector() + numTooShort);
@ -372,34 +417,43 @@ bool PartitionTable::snap(const Device& d, Partition& p, const Partition* origin
p.fileSystem().setFirstSector(snappedFirst);
}
delta = (p.lastSector() + 1) % d.cylinderSize();
delta = (p.lastSector() + 1) % snapSize(d);
if (delta)
{
// Try to snap to the back first...
qint64 snappedLast = p.lastSector() + d.cylinderSize() - delta;
qint64 snappedLast = p.lastSector() + snapSize(d) - delta;
if (d.partitionTable()->type() == msdos_vista)
{
while (snappedLast < d.totalSectors() && QString::number(snappedLast).right(snappedLastString(d).length()) != snappedLastString(d))
{
// kDebug() << "snappedLast: " << snappedLast;
snappedLast += snapSize(d);
}
}
// .. but if we can retain the partition length exactly by snapping to the front ...
if (lengthIsSnapped && p.length() - originalLength == delta)
snappedLast -= d.cylinderSize();
snappedLast -= snapSize(d);
// ... or if there's something there already, snap to the front.
else if (!canSnapToSector(d, p, snappedLast, originalPartition))
snappedLast -= d.cylinderSize();
snappedLast -= snapSize(d);
p.setLastSector(snappedLast);
p.fileSystem().setLastSector(snappedLast);
}
// Now, did we make the partition too big for its file system?
while (p.length() > originalLength && p.capacity() > p.fileSystem().maxCapacity() && canSnapToSector(d, p, p.lastSector() - d.cylinderSize(), originalPartition))
while (p.length() > originalLength && p.capacity() > p.fileSystem().maxCapacity() && canSnapToSector(d, p, p.lastSector() - snapSize(d), originalPartition))
{
p.setLastSector(p.lastSector() - d.cylinderSize());
p.fileSystem().setLastSector(p.fileSystem().lastSector() - d.cylinderSize());
p.setLastSector(p.lastSector() - snapSize(d));
p.fileSystem().setLastSector(p.fileSystem().lastSector() - snapSize(d));
}
if (p.length() < originalLength)
Log(Log::warning) << i18ncp("@info/plain", "The partition cannot be created with the requested length of 1 sector, ", "The partition cannot be created with the requested length of %1 sectors, ", originalLength)
+ i18ncp("@info/plain", "and will instead only be 1 sector long.", "and will instead only be %1 sectors long.", p.length());
+ i18ncp("@info/plain", "and will instead only be 1 sector long.", "and will instead only be %1 sectors long.", p.length());
// In an extended partition we also need to snap unallocated children at the beginning and at the end
// (there should never be a need to snap non-unallocated children)