@Override
public short unlink(final long parentId, final String fileName, final AtomicDBUpdate update)
throws DatabaseException {
try {
// retrieve the file metadata
BufferBackedFileMetadata file = BabuDBStorageHelper.getMetadata(database, parentId, fileName);
// determine and set the new link count
short newLinkCount = (short) (file.getLinkCount() - 1);
file.setLinkCount(newLinkCount);
// if there will be links remaining after the deletion, update the
// link count; it must be in the FILE_ID_INDEX, because there have
// been at least two links
if (newLinkCount > 0)
update.addUpdate(
FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(file.getId(), FileMetadata.RC_METADATA),
file.getRCMetadata().getValue());
// remove all entries from the file index
update.addUpdate(
FILE_INDEX,
BabuDBStorageHelper.createFileKey(parentId, fileName, FileMetadata.FC_METADATA),
null);
update.addUpdate(
FILE_INDEX,
BabuDBStorageHelper.createFileKey(parentId, fileName, FileMetadata.RC_METADATA),
null);
return newLinkCount;
} catch (BabuDBException exc) {
throw new DatabaseException(exc);
}
}
@Override
public void link(
final FileMetadata metadata,
final long newParentId,
final String newFileName,
final AtomicDBUpdate update) {
// get the link source
BufferBackedFileMetadata md = (BufferBackedFileMetadata) metadata;
// increment the link count
short links = metadata.getLinkCount();
md.setLinkCount((short) (links + 1));
// insert the whole metadata of the original file in the file ID
// index
update.addUpdate(
FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(metadata.getId(), FileMetadata.FC_METADATA),
md.getFCMetadataValue());
update.addUpdate(
FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(metadata.getId(), FileMetadata.RC_METADATA),
md.getRCMetadata().getValue());
// remove the back link
update.addUpdate(
FILE_ID_INDEX, BabuDBStorageHelper.createFileIdIndexKey(metadata.getId(), (byte) 3), null);
// if the metadata was retrieved from the FILE_INDEX and hasn't
// been deleted before (i.e. links == 0), ensure that the original
// file in the file index now points to the file ID index, and
// remove the FC and XLoc metadata entries
if (links != 0 && md.getIndexId() == FILE_INDEX) {
update.addUpdate(
FILE_INDEX,
md.getRCMetadata().getKey(),
BabuDBStorageHelper.createLinkTarget(metadata.getId()));
update.addUpdate(FILE_INDEX, md.getFCMetadataKey(), null);
}
// create an entry for the new link to the metadata in the file
// index
update.addUpdate(
FILE_INDEX,
BabuDBStorageHelper.createFileKey(newParentId, newFileName, FileMetadata.RC_METADATA),
BabuDBStorageHelper.createLinkTarget(metadata.getId()));
}
@Override
public FileMetadata getMetadata(long fileId) throws DatabaseException {
try {
// create the key for the file ID index lookup
byte[] key = BabuDBStorageHelper.createFileIdIndexKey(fileId, (byte) -1);
ByteBuffer.wrap(key).putLong(fileId);
byte[][] valBufs = new byte[BufferBackedFileMetadata.NUM_BUFFERS][];
// retrieve the metadata from the link index
ResultSet<byte[], byte[]> it =
database.prefixLookup(BabuDBStorageManager.FILE_ID_INDEX, key, null).get();
while (it.hasNext()) {
Entry<byte[], byte[]> curr = it.next();
int type = BabuDBStorageHelper.getType(curr.getKey(), BabuDBStorageManager.FILE_ID_INDEX);
// if the value is a back link, resolve it
if (type == 3) {
long parentId = ByteBuffer.wrap(curr.getValue()).getLong();
String fileName = new String(curr.getValue(), 8, curr.getValue().length - 8);
return getMetadata(parentId, fileName);
}
valBufs[type] = curr.getValue();
}
it.free();
// if not metadata was found for the file ID, return null
if (valBufs[FileMetadata.RC_METADATA] == null) return null;
byte[][] keyBufs =
new byte[][] {null, BabuDBStorageHelper.createFileKey(0, "", FileMetadata.RC_METADATA)};
// otherwise, a hard link target is contained in the index; create a
// new metadata object in this case
return new BufferBackedFileMetadata(keyBufs, valBufs, BabuDBStorageManager.FILE_ID_INDEX);
} catch (BabuDBException exc) {
throw new DatabaseException(exc);
}
}
@Override
public short delete(final long parentId, final String fileName, final AtomicDBUpdate update)
throws DatabaseException {
try {
// retrieve the file metadata
BufferBackedFileMetadata file = BabuDBStorageHelper.getMetadata(database, parentId, fileName);
// check whether there is only one link remaining
short newLinkCount = (short) (file.getLinkCount() - 1);
assert (newLinkCount >= 0);
// decrement the link count
file.setLinkCount(newLinkCount);
// if there will be links remaining after the deletion, update the
// link count
if (newLinkCount > 0)
update.addUpdate(
FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(file.getId(), FileMetadata.RC_METADATA),
file.getRCMetadata().getValue());
// delete all keys ...
// remove all content from the file index
update.addUpdate(
BabuDBStorageManager.FILE_INDEX,
BabuDBStorageHelper.createFileKey(parentId, fileName, FileMetadata.FC_METADATA),
null);
update.addUpdate(
BabuDBStorageManager.FILE_INDEX,
BabuDBStorageHelper.createFileKey(parentId, fileName, FileMetadata.RC_METADATA),
null);
// if the last link to the file is supposed to be deleted, remove
// the remaining metadata, including ACLs and XAttrs
if (newLinkCount == 0) {
// remove the back link from the file ID index
update.addUpdate(
BabuDBStorageManager.FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(file.getId(), (byte) 3),
null);
// remove potentially existing metadata from the file ID index
update.addUpdate(
BabuDBStorageManager.FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(file.getId(), FileMetadata.FC_METADATA),
null);
update.addUpdate(
BabuDBStorageManager.FILE_ID_INDEX,
BabuDBStorageHelper.createFileIdIndexKey(file.getId(), FileMetadata.RC_METADATA),
null);
byte[] idBytes = new byte[8];
ByteBuffer.wrap(idBytes).putLong(file.getId());
// remove all ACLs
ResultSet<byte[], byte[]> it =
database.prefixLookup(BabuDBStorageManager.ACL_INDEX, idBytes, null).get();
while (it.hasNext())
update.addUpdate(BabuDBStorageManager.ACL_INDEX, it.next().getKey(), null);
it.free();
// remove all extended attributes
it = database.prefixLookup(BabuDBStorageManager.XATTRS_INDEX, idBytes, null).get();
while (it.hasNext())
update.addUpdate(BabuDBStorageManager.XATTRS_INDEX, it.next().getKey(), null);
it.free();
// if a file is deleted, update file count and volume size
if (file.isDirectory()) {
updateCount(NUM_DIRS_KEY, false, update);
} else if (file.getXLocList() != null) {
volume.updateVolumeSize(-file.getSize(), update);
updateCount(NUM_FILES_KEY, false, update);
}
}
return file.getLinkCount();
} catch (BabuDBException exc) {
throw new DatabaseException(exc);
}
}
@Override
public void createSnapshot(String snapName, long parentId, String dirName, boolean recursive)
throws DatabaseException {
try {
// determine the prefixes for the snapshot
byte[][][] prefixes = null;
FileMetadata snapDir = getMetadata(parentId, dirName);
// for a full volume snapshot, simply use a 'null' prefix (full:
// dirID == 1 && recursive)
if (snapDir.getId() != 1 || !recursive) {
// get the IDs of all files and directories contained in the
// given directory; if recursive == true, include subdirectories
List<FileMetadata> nestedFiles = new LinkedList<FileMetadata>();
BabuDBStorageHelper.getNestedFiles(nestedFiles, database, snapDir.getId(), recursive);
List<byte[]> dirEntryPrefixes = new ArrayList<byte[]>(nestedFiles.size());
List<byte[]> filePrefixes = new ArrayList<byte[]>(nestedFiles.size());
// include the extended attributes of the volume's root
// directory if it's not the snapshot directory - they are
// needed to access volume-wide parameters in the snapshot, such
// as the access control policy
if (snapDir.getId() != 1) filePrefixes.add(ByteBuffer.wrap(new byte[8]).putLong(1).array());
// include all metadata of the snapshot (i.e. top level) dir
byte[] idxKey = BabuDBStorageHelper.createFileKey(parentId, dirName, (byte) -1);
byte[] fileKey = BabuDBStorageHelper.createFilePrefixKey(snapDir.getId());
dirEntryPrefixes.add(idxKey);
filePrefixes.add(fileKey);
// include the snapshot directory content
idxKey = BabuDBStorageHelper.createFilePrefixKey(snapDir.getId());
dirEntryPrefixes.add(idxKey);
// determine the key prefixes of all nested files to include and
// exclude
for (FileMetadata file : nestedFiles) {
// create a prefix key for the nested file
byte[] key = BabuDBStorageHelper.createFilePrefixKey(file.getId());
// if the nested file is a directory, ...
if (file.isDirectory()) {
// include the directory in the file prefixes
// and the directory prefix in the dir entry prefixes
filePrefixes.add(key);
dirEntryPrefixes.add(key);
}
// if the nested file is a file, ...
else filePrefixes.add(key);
}
byte[][] dirEntryPrefixesA = dirEntryPrefixes.toArray(new byte[dirEntryPrefixes.size()][]);
byte[][] filePrefixesA = filePrefixes.toArray(new byte[filePrefixes.size()][]);
Arrays.sort(dirEntryPrefixesA, DefaultByteRangeComparator.getInstance());
Arrays.sort(filePrefixesA, DefaultByteRangeComparator.getInstance());
// FILE_INDEX, XATTRS_INDEX, ACL_INDEX, FILE_ID_INDEX,
// VOLUME_INDEX
prefixes =
new byte[][][] {dirEntryPrefixesA, filePrefixesA, filePrefixesA, filePrefixesA, null};
}
// create the snapshot
SnapshotConfig snap = new DefaultSnapshotConfig(snapName, ALL_INDICES, prefixes, null);
snapMan.createPersistentSnapshot(database.getName(), snap);
} catch (BabuDBException exc) {
throw new DatabaseException(exc);
}
}
