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#!/usr/bin/env python
# RaidGuessFS, a FUSE pseudo-filesystem to guess RAID parameters of a damaged device
# Copyright (C) 2015 Ludovic Pouzenc <ludovic@pouzenc.fr>
#
# This file is part of RaidGuessFS.
#
# RaidGuessFS 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 3 of the License, or
# (at your option) any later version.
#
# RaidGuessFS 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with RaidGuessFS. If not, see <http://www.gnu.org/licenses/>
import logging
import myraidmaths
class MyRaid():
"""Auxiliary class, managing RAID layer"""
RAID_TYPES = [ '0', '1', '5', '5+0' ]
RAID5_LAYOUTS = [ 'la', 'ra', 'ls', 'rs' ]
def __init__(self, mydisks):
self.d = mydisks
self.raid_start = 0
self.raid_end = 0
self.raid_chunk_size = 65536
self.raid_disk_order = []
self.raid_disk_count = 0
self.raid_type = '5'
self.raid_layout = 'ls'
self.raid_disks = []
self.raid_subraid_count = 2
def get_raid_start(self):
return self.raid_start
def get_raid_end(self):
return self.raid_end
def get_raid_chunk_size(self):
return self.raid_chunk_size
def get_raid_disk_order(self):
return self.raid_disk_order
def get_raid_disk_order_str(self):
return ' '.join(map(str,self.raid_disk_order))
def get_raid_type(self):
return self.raid_type
def get_raid_layout(self):
return self.raid_layout
def get_raid_subraid_count(self):
return self.raid_subraid_count
def set_disks(self, new_mydisks):
# FIXME : self.d don't need to be updaed (pass on __init__)
self.d = new_mydisks
self.set_raid_disk_order(range(self.d.disk_count))
def set_raid_start(self, new_raid_start):
"""Update the start offset of raid data on underlying disks"""
self.raid_start = new_raid_start
def set_raid_end(self, new_raid_end):
"""Update the end offset of raid data on underlying disks"""
self.raid_end = new_raid_end
def set_raid_chunk_size(self, new_raid_chunk_size):
"""Update the size of chucks of data (or slice size)"""
self.raid_chunk_size = new_raid_chunk_size
def set_raid_disk_order(self, new_raid_disk_order):
"""Update the raid logical disk order"""
check=[0] * self.d.disk_count
for item in new_raid_disk_order:
d = int(item)
if not 0 <= d < self.d.disk_count:
raise ValueError('Value out of range : %i [0,%i]'%(d,self.d.disk_count-1))
check[d]=check[d]+1
for d in range(self.d.disk_count):
if check[d] != 1 and check[d] != 0:
raise ValueError('Disk %i appears %i times (must be 0 or 1)'%(d,check[d]))
self.raid_disk_count = len(new_raid_disk_order)
self.raid_disk_order = new_raid_disk_order
self.raid_disks = [ self.d.disks[i] for i in self.raid_disk_order ]
def set_raid_type(self, new_raid_type):
if new_raid_type in MyRaid.RAID_TYPES:
self.raid_type = new_raid_type
else:
raise ValueError('raid_type has to be one of %s'%' '.join(MyRaid.RAID_TYPES))
def set_raid_subraid_count(self, new_raid_subraid_count):
"""Update the number of subcomponents in nested RAID levels"""
self.raid_subraid_count = new_raid_subraid_count
def set_raid_layout(self, new_raid_layout):
"""Update the kind of data/parity block layout for RAID5 family"""
if new_raid_layout in MyRaid.RAID5_LAYOUTS:
self.raid_layout = new_raid_layout
else:
raise ValueError('raid_layout has to be one of %s'%' '.join(MyRaid.RAID_LAYOUTS))
def sizeof_raid_result(self):
size = max(0, self.raid_end - self.raid_start)
return {
'0' : size * self.raid_disk_count,
'1' : size if self.raid_disk_count == 2 else 0,
'5' : size * (self.raid_disk_count - 1) if self.raid_disk_count >= 3 else 0,
'5+0': size * (self.raid_disk_count - 2) if self.raid_disk_count >= 6 and self.raid_disk_count % 2 == 0 else 0,
}[self.raid_type]
def sizeof_disk_xor(self):
return max(0, self.raid_end - self.raid_start)
def sizeof_disk_parity(self):
size = max(0, self.raid_end - self.raid_start) / self.d.sector_size * 16
return {
'0' : 64,
'1' : size if self.raid_disk_count == 2 else 64,
'5' : size if self.raid_disk_count >= 3 else 64,
'5+0': size if self.raid_disk_count >= 6 and self.raid_disk_count % 2 == 0 else 64,
}[self.raid_type]
def read_disk_xor(self,offset,size):
"""Returns raw bitwise XOR against a bunch of disks slice"""
return myraidmaths.MyRaidMaths.xor_blocks(self.raid_disks,offset,size)[1]
def read_disk_parity(self,offset,size):
"""Returns textual information about parity status of each sector"""
logging.warn("Enter read_disk_parity(%d,%d)"%(offset,size))
msg = {
'0' : 'There no notion of parity in RAID 0 mode\n',
'1' : None if self.raid_disk_count == 2 else 'Wrong disk count (should be 2)\n',
'5' : None if self.raid_disk_count >= 3 else 'Wrong disk count (should be >=3)\n',
'5+0': None if self.raid_disk_count >= 6 and self.raid_disk_count % 2 == 0
else 'Wrong disk count (should be >=6 and even)\n',
}[self.raid_type]
if msg:
return msg[offset:offset+size]
start = self.raid_start + offset * self.d.sector_size / 16
end = start + size * self.d.sector_size / 16
#TODO : improove for nested levels
if self.raid_type in ['1','5', '5+0']:
result = ''.join(
[ '0x%011x %c\n'%( addr, myraidmaths.MyRaidMaths.xor_blocks(self.raid_disks, addr, self.d.sector_size)[0])
for addr in xrange(start, end, self.d.sector_size)
])
else:
result = None
logging.warn("Exit. read_disk_parity(%d,%d)"%(offset,size))
return result
def read_raid_result(self,offset,size):
"""Returns actual RAID data"""
res = myraidmaths.MyRaidMaths.apply_raid_layout(offset, size, self.raid_type, self.raid_layout, self.raid_chunk_size, self.raid_disk_count, self.raid_start, self.raid_subraid_count);
(segment_no, segment_off, stripe_no, subraid_no, par_disk, data_disk, off_disk, aligned_read_size) = res
logging.debug("raid.read_result(%s): offset=%d,segment_no=%d,segment_off=%d,stripe_no=%d,subraid_no=%d,par_disk=%d(disk%02d),data_disk=%d(disk%02d),off_disk=%d,aligned_read_size=%d,segment_off+aligned_read_size=%d"
% (self.raid_type,offset,segment_no,segment_off,stripe_no,subraid_no,par_disk,self.raid_disk_order[par_disk],data_disk,self.raid_disk_order[data_disk],off_disk,aligned_read_size,segment_off+aligned_read_size) )
data_fd = self.raid_disks[data_disk]
if self.d.is_readable(self.raid_disk_order[data_disk],off_disk,aligned_read_size):
# No damaged sectors until the end of the chunck, so just read the data disk
data_fd.seek(off_disk)
data = data_fd.read(aligned_read_size)
else:
# TODO : this is only for RAID5
logging.warn('Try to recovering damaged chunck (raid_offset: 0x%011x, data_disk: %i, disk_offset: 0x%011x'
% (offset, self.raid_disk_order[data_disk], off_disk) )
# Damaged sectors, check / recover every sector
other_disks = list(self.raid_disk_order)
other_disks.remove(self.raid_disk_order[data_disk])
other_fds = list(self.raid_disks)
other_fds.remove(data_fd)
data_arr = []
for s in xrange(off_disk, off_disk+aligned_read_size, self.d.sector_size):
if self.d.is_readable(self.raid_disk_order[data_disk],s,self.d.sector_size):
# Current sector is readable from data disk, read it
logging.debug('-> 0x%011x : readable'%s)
data_fd.seek(off_disk)
data_arr.append(data_fd.read(self.d.sector_size))
else:
# Current sector is dead on data disk, recover it if possible
recoverable = reduce(lambda a,b: a and b, [
self.d.is_readable(other_disk,off_disk,self.d.sector_size) for other_disk in other_disks
])
if recoverable:
logging.info('-> 0x%011x : recoverable'%s)
data_arr.append( myraidmaths.MyRaidMaths.xor_blocks(other_fds, s,self.d.sector_size)[1] )
else:
logging.warn('-> 0x%011x : unrecoverable'%s)
data_arr.append( '\0' * self.d.sector_size)
data = ''.join(data_arr)
# Prevent short reads, seems mandatory for losetup'ing raid_result but kills performance
#TODO : make it activable per config
if aligned_read_size < size:
return ''.join( (data, self.read_raid_result(offset + aligned_read_size, size - aligned_read_size) ) )
return data
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