#!/usr/bin/python
#
# determine which LVM2 logical volume spans a hard disk block.
# useful when you get messages about defective hard disk blocks from
# SMART and you want to find out which volume is affected.

# Usage:
#
# Option 1:
#
# badblocklocate disk 
#  Queries smartctl for bad blocks and locates them.
#
# Option 2:
# 
# badblocklocate disk blockno [blockno blockno ...]
#  Find the volums corresponding to the blockno given on the command line
#
#
# Mail me at florian@void.s.bawue.de for questions and suggestions.
#
# Florian Laws


# LICENSE:
#    This program 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.
#
#    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.




import sys
import os
from subprocess import *

disk = sys.argv[1]

def find_partition(sector):
    output = Popen(["fdisk","-lu",disk],stdout=PIPE).communicate()[0]
    
    for line in output.split('\n'):
        if line.startswith('/'):
            parts = line.strip().split()
            partdev = parts[0]
            if parts[1] == '*':
                # Partition has boot flag, delete this field, so numbering matches non-boot partitions
                del parts[1]
            start = int(parts[1])
            end = int(parts[2])
            parttype = parts[4]
            if sector >= start and sector <= end:
                # found the right partition
                return { 'dev' : partdev, 'start' : start, 'end' : end, 'type' : parttype, 'offset' : sector - start }
                
    # didn't find anything
    return None
        

def find_lv(partition, offset):
    #print "Warning: assuming LINEAR allocation policy"
    
    # determine PE size
    output = Popen(["pvdisplay","-c",partition],stdout=PIPE).communicate()[0]
    parts = output.split(":")
    # PE size is given in KB by pvdisplay - multiply by 2 to get size in terms of LBA blocks
    PE_size = int(parts[7]) * 2
    #print "PE size for %s is %d blocks" % (partition, PE_size)

    PE_rank = offset / PE_size
    #print "PE rank" , PE_rank
    
    # get LV-to-PE mappings
    output = Popen(["lvs","--noheadings","-o","seg_pe_ranges,vg_name,lv_name","-O","seg_start_pe"],stdout=PIPE).communicate()[0]
#    print output
    for line in output.strip().split('\n'):
        pv_range, vg, lvname = line.split()
        pv, pe_range = pv_range.split(':')
        if pv != partition: 
            continue
        pe_range_parts = pe_range.split('-')
        pe_start = int(pe_range_parts[0])
        pe_end = int(pe_range_parts[1])
        if pe_start <= PE_rank and PE_rank <= pe_end:
            return (vg, lvname)

    # No LV found            
    return None       

bad_sectors = []

if len(sys.argv) > 2:
    # get sector numbers from command line.
    for a in sys.argv[2:]:
        bad_sectors.append( int(a) )
        
else:         

    print "Getting list of defective sectors from %s" % ( disk )

    output = Popen(["smartctl", "-l","selftest", disk],stdout=PIPE,universal_newlines=True).communicate()[0]

    #print repr(output)


    for line in output.split('\n'): 
        if line.startswith('#'):
            parts = line.strip().split()
            bad_sectors.append( int(parts[9]) )
            
    #print bad_sectors      

for s in bad_sectors:
    partition = find_partition(s)
    
    if partition['type'] == '8e':
        #print "%(dev)s is LVM partition" % partition
        lvinfo =  find_lv(partition['dev'], partition['offset'])
        if not lvinfo:
            print "%d: LV not found - probably unallocated area." % (s)
        else:
            print s, lvinfo[0], lvinfo[1]
    else:
        print "%d: %s is not an LVM partition - partition type %s is not supported. skipping." % (s, partition['dev'], partition['type'])