class PpFs(fuse.Fuse):
def __init__(self, *args, **kw):
fuse.Fuse.__init__(self, *args, **kw)
self.blocks_nr = 120
self.block_size = 8 * 1024
self.K = 5
self.device = Device("data", self.block_size, self.blocks_nr + self.K)
self.wrapper = DeviceWrapper(self.device)
# metadata is held in last self.K blocks of device
self.meta_blocks = list(range(self.blocks_nr, self.blocks_nr + self.K))
self.meta = self.__get_meta()
def __get_meta(self):
try:
data_size = self.K * self.block_size
data = self.wrapper.read(0, data_size, self.meta_blocks)
return pickle.loads(data)
except:
return Metadata(self.blocks_nr)
def pickle_metadata(self):
pickled = pickle.dumps(self.meta)
self.wrapper.write(0, pickled, self.meta_blocks)
def getattr(self, path):
if not self.meta.exists(path):
return -errno.ENOENT
return self.meta.get_element(path).attributes
def readdir(self, path, offset):
node = self.meta.get_element(path)
for d in node.elements.iterkeys():
yield fuse.Direntry(d)
def mknod(self, path, mode, dev):
return self.create(path, None, mode)
@metachanger
def create(self, path, flags, mode):
self.meta.add_element(path, False, mode)
@metachanger
def mkdir(self, path, mode):
self.meta.add_element(path, True, mode)
@metachanger
def rmdir(self, path):
return self.unlink(path)
@metachanger
def unlink(self, path):
self.meta.remove(self.meta.get_element(path))
def read(self, path, size, offset):
blocks = self.meta.get_element(path).blocks
return self.wrapper.read(offset, size, blocks)
@metachanger
def write(self, path, buff, offset):
node = self.meta.get_element(path)
buff_end = offset + len(buff)
# reserve enough blocks for file to hold data
while len(node.blocks) * self.block_size < buff_end:
self.meta.reserve_block_for(node)
self.wrapper.write(offset, buff, node.blocks)
node.attributes.st_size = max([node.attributes.st_size, buff_end])
return len(buff)
def release(self, path, flags):
return self.flush(path, None)
def fsync(self, path, isfsyncfile):
return self.flush(path, None)
def flush(self, path, fh=None):
self.device.flush()
return 0
def open(self, path, flags):
return 0
@metachanger
def rename(self, pathfrom, pathto):
self.meta.move(pathfrom, pathto)
@metachanger
def chmod(self, path, mode):
node = self.meta.get_element(path)
node.attributes.change_mode(mode)
@metachanger
def chown(self, path, uid, gid):
node = self.meta.get_element(path)
if uid >= 0:
node.attributes.st_uid = uid
if gid >= 0:
node.attributes.st_gid = gid
def truncate(self, path, size):
return 0
def utime(self, path, times):
return 0
