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#!/usr/bin/python 

# 

# Copyright (C) Citrix Systems Inc. 

# 

# This program is free software; you can redistribute it and/or modify  

# it under the terms of the GNU Lesser General Public License as published  

# by the Free Software Foundation; version 2.1 only. 

# 

# 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 Lesser General Public License for more details. 

# 

# You should have received a copy of the GNU Lesser General Public License 

# along with this program; if not, write to the Free Software Foundation, Inc., 

# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA 

# 

# Miscellaneous LVM utility functions 

# 

 

 

import re 

import os 

import errno 

import time 

 

import lock 

import util 

import xs_errors 

import xml.dom.minidom 

from lvhdutil import VG_LOCATION,VG_PREFIX 

from constants import EXT_PREFIX 

import lvmcache 

import srmetadata 

 

MDVOLUME_NAME = 'MGT' 

VDI_UUID_TAG_PREFIX = 'vdi_' 

LVM_BIN = os.path.isfile('/sbin/lvdisplay') and '/sbin' or '/usr/sbin' 

CMD_VGS       = "vgs" 

CMD_VGCREATE  = "vgcreate" 

CMD_VGREMOVE  = "vgremove" 

CMD_VGCHANGE  = "vgchange" 

CMD_VGEXTEND  = "vgextend" 

CMD_PVS       = "pvs" 

CMD_PVCREATE  = "pvcreate" 

CMD_PVREMOVE  = "pvremove" 

CMD_PVRESIZE  = "pvresize" 

CMD_LVS       = "lvs" 

CMD_LVDISPLAY = "lvdisplay" 

CMD_LVCREATE  = "lvcreate" 

CMD_LVREMOVE  = "lvremove" 

CMD_LVCHANGE  = "lvchange" 

CMD_LVRENAME  = "lvrename" 

CMD_LVRESIZE  = "lvresize" 

CMD_LVEXTEND  = "lvextend" 

CMD_DMSETUP   = "/sbin/dmsetup" 

 

MAX_OPERATION_DURATION = 15 

 

LVM_SIZE_INCREMENT = 4 * 1024 * 1024 

LV_TAG_HIDDEN = "hidden" 

LVM_FAIL_RETRIES = 10 

 

MASTER_LVM_CONF = '/etc/lvm/master' 

DEF_LVM_CONF = '/etc/lvm' 

 

VG_COMMANDS = frozenset({CMD_VGS, CMD_VGCREATE, CMD_VGREMOVE, CMD_VGCHANGE, 

                         CMD_VGEXTEND}) 

PV_COMMANDS = frozenset({CMD_PVS, CMD_PVCREATE, CMD_PVREMOVE, CMD_PVRESIZE}) 

LV_COMMANDS = frozenset({CMD_LVS, CMD_LVDISPLAY, CMD_LVCREATE, CMD_LVREMOVE, 

                         CMD_LVCHANGE, CMD_LVRENAME, CMD_LVRESIZE, 

                         CMD_LVEXTEND}) 

DM_COMMANDS = frozenset({CMD_DMSETUP}) 

 

LVM_COMMANDS = VG_COMMANDS.union(PV_COMMANDS, LV_COMMANDS, DM_COMMANDS) 

 

LVM_LOCK = 'lvm' 

 

 

def extract_vgname(str_in): 

    """Search for and return a VG name 

 

        Search 'str_in' for a substring in the form of 'VG_XenStorage-<UUID>'.  

        If there are more than one VG names, the first is returned. 

 

        Input: 

            str_in -- (str) string to search for a VG name 

                            in the format specified above. 

 

        Return: 

            vgname -- if found     -> (str) 

                      if not found -> None 

 

        Raise: 

            TypeError 

    """ 

 

    if not util.is_string(str_in): 

        raise TypeError("'str_in' not of type 'str'.") 

 

    i = str_in.find(VG_PREFIX) 

    prefix = VG_PREFIX 

 

    if i == -1: 

        i = str_in.find(EXT_PREFIX) 

        prefix = EXT_PREFIX 

 

    uuid_start = i + len(prefix) 

    re_obj = util.match_uuid(str_in[uuid_start:]) 

 

    if i != -1 and re_obj: 

        return prefix + re_obj.group(0) # vgname 

 

    return None 

 

class LvmLockContext(object): 

    """ 

    Context manager around the LVM lock. 

 

    To allow for higher level operations, e.g. VDI snapshot to pre-emptively 

    acquire the lock to encapsulte a set of calls and avoid having to reacquire 

    the locks for each LVM call. 

    """ 

 

    def __init__(self, cmd=None): 

        self.lock = lock.Lock(LVM_LOCK) 

        self.cmd = cmd 

        self.locked = False 

 

    def __enter__(self): 

132        if self.cmd and '--readonly' in self.cmd: 

            return 

 

        self.lock.acquire() 

        self.locked = True 

 

    def __exit__(self, exc_type, value, traceback): 

exit        if self.locked: 

            self.lock.release() 

 

def cmd_lvm(cmd, pread_func=util.pread2, *args): 

    """ Construct and run the appropriate lvm command. 

 

        For PV commands, the full path to the device is required. 

 

        Input: 

            cmd -- (list) lvm command 

                cmd[0]  -- (str) lvm command name 

                cmd[1:] -- (str) lvm command parameters 

 

            pread_func -- (function) the flavor of util.pread to use 

                                     to execute the lvm command 

                Default: util.pread2() 

 

            *args -- extra arguments passed to cmd_lvm will be passed 

                     to 'pread_func' 

 

        Return: 

            stdout -- (str) stdout after running the lvm command. 

 

        Raise: 

            util.CommandException 

    """ 

 

166    if type(cmd) is not list: 

        util.SMlog("CMD_LVM: Argument 'cmd' not of type 'list'") 

        return None 

169    if not len(cmd): 

        util.SMlog("CMD_LVM: 'cmd' list is empty") 

        return None 

 

    lvm_cmd, lvm_args = cmd[0], cmd[1:] 

 

175    if lvm_cmd not in LVM_COMMANDS: 

        util.SMlog("CMD_LVM: '{}' is not a valid lvm command".format(lvm_cmd)) 

        return None 

 

    for arg in lvm_args: 

180        if not util.is_string(arg): 

            util.SMlog("CMD_LVM: Not all lvm arguments are of type 'str'") 

            return None 

 

    with LvmLockContext(cmd): 

        start_time = time.time() 

        stdout = pread_func([os.path.join(LVM_BIN, lvm_cmd)] + lvm_args, *args) 

        end_time = time.time() 

 

189    if (end_time - start_time > MAX_OPERATION_DURATION): 

        util.SMlog("***** Long LVM call of '%s' took %s" % (lvm_cmd, (end_time - start_time))) 

 

    return stdout 

 

 

class LVInfo: 

    name = "" 

    size = 0 

    active = False 

    open = False 

    hidden = False 

    readonly = False 

 

    def __init__(self, name): 

        self.name = name 

 

    def toString(self): 

        return "%s, size=%d, active=%s, open=%s, hidden=%s, ro=%s" % \ 

                (self.name, self.size, self.active, self.open, self.hidden, \ 

                self.readonly) 

 

def _checkVG(vgname): 

    try: 

        cmd_lvm([CMD_VGS, "--readonly", vgname]) 

        return True 

    except: 

        return False 

 

def _checkPV(pvname): 

    try: 

        cmd_lvm([CMD_PVS, pvname]) 

        return True 

    except: 

        return False 

 

def _checkLV(path): 

    try: 

        cmd_lvm([CMD_LVDISPLAY, path]) 

        return True 

    except: 

        return False 

 

def _getLVsize(path): 

    try: 

        lines = cmd_lvm([CMD_LVDISPLAY, "-c", path]).split(':') 

        return long(lines[6]) * 512 

    except: 

        raise xs_errors.XenError('VDIUnavailable', \ 

              opterr='no such VDI %s' % path) 

 

def _getVGstats(vgname): 

    try: 

        text = cmd_lvm([CMD_VGS, "--noheadings", "--nosuffix", 

                        "--units", "b", vgname], 

                        pread_func=util.pread).split() 

        size = long(text[5]) 

        freespace = long(text[6]) 

        utilisation = size - freespace 

        stats = {} 

        stats['physical_size'] = size 

        stats['physical_utilisation'] = utilisation 

        stats['freespace'] = freespace 

        return stats 

    except util.CommandException, inst: 

        raise xs_errors.XenError('VDILoad', \ 

              opterr='rvgstats failed error is %d' % inst.code) 

    except ValueError: 

        raise xs_errors.XenError('VDILoad', opterr='rvgstats failed') 

 

def _getPVstats(dev): 

    try: 

        text = cmd_lvm([CMD_PVS, "--noheadings", "--nosuffix", 

                        "--units", "b", dev], 

                        pread_func=util.pread).split() 

        size = long(text[4]) 

        freespace = long(text[5]) 

        utilisation = size - freespace 

        stats = {} 

        stats['physical_size'] = size 

        stats['physical_utilisation'] = utilisation 

        stats['freespace'] = freespace 

        return stats 

    except util.CommandException, inst: 

        raise xs_errors.XenError('VDILoad', \ 

              opterr='pvstats failed error is %d' % inst.code) 

    except ValueError: 

        raise xs_errors.XenError('VDILoad', opterr='rvgstats failed') 

 

# Retrieves the UUID of the SR that corresponds to the specified Physical 

# Volume (pvname). Each element in prefix_list is checked whether it is a 

# prefix of Volume Groups that correspond to the specified PV. If so, the 

# prefix is stripped from the matched VG name and the remainder is returned 

# (effectively the SR UUID). If no match if found, the empty string is 

# returned. 

# E.g. 

#   PV         VG                          Fmt  Attr PSize   PFree   

#  /dev/sda4  VG_XenStorage-some-hex-value lvm2 a-   224.74G 223.73G 

# will return "some-hex-value". 

def _get_sr_uuid(pvname, prefix_list): 

    try: 

        return match_VG(cmd_lvm([CMD_PVS, "--noheadings", 

                        "-o", "vg_name", pvname]), prefix_list) 

    except: 

        return "" 

 

# Tries to match any prefix contained in prefix_list in s. If matched, the 

# remainder string is returned, else the empty string is returned. E.g. if s is 

# "VG_XenStorage-some-hex-value" and prefix_list contains "VG_XenStorage-", 

# "some-hex-value" is returned. 

# 

# TODO Items in prefix_list are expected to be found at the beginning of the 

# target string, though if any of them is found inside it a match will be 

# produced. This could be remedied by making the regular expression more 

# specific. 

def match_VG(s, prefix_list): 

    for val in prefix_list: 

        regex = re.compile(val) 

        if regex.search(s, 0): 

            return s.split(val)[1] 

    return "" 

 

# Retrieves the devices an SR is composed of. A dictionary is returned, indexed 

# by the SR UUID, where each SR UUID is mapped to a comma-separated list of 

# devices. Exceptions are ignored. 

def scan_srlist(prefix, root): 

    VGs = {} 

    for dev in root.split(','): 

        try: 

            sr_uuid = _get_sr_uuid(dev, [prefix]).strip(' \n') 

            if len(sr_uuid): 

                if VGs.has_key(sr_uuid): 

                    VGs[sr_uuid] += ",%s" % dev 

                else: 

                    VGs[sr_uuid] = dev 

        except Exception, e: 

            util.logException("exception (ignored): %s" % e) 

            continue 

    return VGs 

 

# Converts an SR list to an XML document with the following structure: 

# <SRlist> 

#   <SR> 

#       <UUID>...</UUID> 

#       <Devlist>...</Devlist> 

#       <size>...</size> 

#       <!-- If includeMetadata is set to True, the following additional nodes 

#       are supplied. --> 

#       <name_label>...</name_label> 

#       <name_description>...</name_description> 

#       <pool_metadata_detected>...</pool_metadata_detected> 

#   </SR> 

# 

#   <SR>...</SR> 

# </SRlist> 

# 

# Arguments: 

#   VGs: a dictionary containing the SR UUID to device list mappings 

#   prefix: the prefix that if prefixes the SR UUID the VG is produced 

#   includeMetadata (optional): include additional information 

def srlist_toxml(VGs, prefix, includeMetadata = False): 

    dom = xml.dom.minidom.Document() 

    element = dom.createElement("SRlist") 

    dom.appendChild(element) 

 

    for val in VGs: 

        entry = dom.createElement('SR') 

        element.appendChild(entry) 

 

        subentry = dom.createElement("UUID") 

        entry.appendChild(subentry) 

        textnode = dom.createTextNode(val) 

        subentry.appendChild(textnode) 

 

        subentry = dom.createElement("Devlist") 

        entry.appendChild(subentry) 

        textnode = dom.createTextNode(VGs[val]) 

        subentry.appendChild(textnode) 

 

        subentry = dom.createElement("size") 

        entry.appendChild(subentry) 

        size = str(_getVGstats(prefix + val)['physical_size']) 

        textnode = dom.createTextNode(size) 

        subentry.appendChild(textnode) 

 

        if includeMetadata: 

            metadataVDI = None 

 

            # add SR name_label 

            mdpath = os.path.join(VG_LOCATION, VG_PREFIX + val) 

            mdpath = os.path.join(mdpath, MDVOLUME_NAME) 

            try: 

                mgtVolActivated = False 

                if not os.path.exists(mdpath): 

                    # probe happens out of band with attach so this volume 

                    # may not have been activated at this point 

                    lvmCache = lvmcache.LVMCache(VG_PREFIX + val) 

                    lvmCache.activateNoRefcount(MDVOLUME_NAME) 

                    mgtVolActivated = True 

 

                sr_metadata = \ 

                    srmetadata.LVMMetadataHandler(mdpath, \ 

                                                        False).getMetadata()[0] 

                subentry = dom.createElement("name_label") 

                entry.appendChild(subentry) 

                textnode = dom.createTextNode(sr_metadata[srmetadata.NAME_LABEL_TAG]) 

                subentry.appendChild(textnode) 

 

                # add SR description 

                subentry = dom.createElement("name_description") 

                entry.appendChild(subentry) 

                textnode = dom.createTextNode(sr_metadata[srmetadata.NAME_DESCRIPTION_TAG]) 

                subentry.appendChild(textnode) 

 

                # add metadata VDI UUID 

                metadataVDI = srmetadata.LVMMetadataHandler(mdpath, \ 

                                    False).findMetadataVDI() 

                subentry = dom.createElement("pool_metadata_detected") 

                entry.appendChild(subentry) 

                if metadataVDI != None: 

                    subentry.appendChild(dom.createTextNode("true")) 

                else: 

                    subentry.appendChild(dom.createTextNode("false")) 

            finally: 

                if mgtVolActivated: 

                    # deactivate only if we activated it 

                    lvmCache.deactivateNoRefcount(MDVOLUME_NAME) 

 

    return dom.toprettyxml() 

 

def _openExclusive(dev, retry): 

    try: 

        return os.open("%s" % dev, os.O_RDWR | os.O_EXCL) 

    except OSError as ose: 

        opened_by = '' 

        if ose.errno == 16: 

            if retry: 

                util.SMlog('Device %s is busy, settle and one shot retry' % 

                           dev) 

                util.pread2(['/usr/sbin/udevadm', 'settle']) 

                return _openExclusive(dev, False) 

            else: 

                util.SMlog('Device %s is busy after retry' % dev) 

 

        util.SMlog('Opening device %s failed with %d' % (dev, ose.errno)) 

        raise xs_errors.XenError( 

            'SRInUse', opterr=('Device %s in use, please check your existing ' 

                               + 'SRs for an instance of this device') % dev) 

 

def createVG(root, vgname): 

    systemroot = util.getrootdev() 

    rootdev = root.split(',')[0] 

 

    # Create PVs for each device 

    for dev in root.split(','): 

        if dev in [systemroot, '%s1' % systemroot, '%s2' % systemroot]: 

            raise xs_errors.XenError('Rootdev', \ 

                  opterr=('Device %s contains core system files, ' \ 

                          + 'please use another device') % dev) 

        if not os.path.exists(dev): 

            raise xs_errors.XenError('InvalidDev', \ 

                  opterr=('Device %s does not exist') % dev) 

 

        f = _openExclusive(dev, True) 

        os.close(f) 

        try: 

            # Overwrite the disk header, try direct IO first 

            cmd = [util.CMD_DD, "if=/dev/zero", "of=%s" % dev, "bs=1M", 

                    "count=10", "oflag=direct"] 

            util.pread2(cmd) 

        except util.CommandException, inst: 

            if inst.code == errno.EPERM: 

                try: 

                    # Overwrite the disk header, try normal IO 

                    cmd = [util.CMD_DD, "if=/dev/zero", "of=%s" % dev, 

                            "bs=1M", "count=10"] 

                    util.pread2(cmd) 

                except util.CommandException, inst: 

                    raise xs_errors.XenError('LVMWrite', \ 

                          opterr='device %s' % dev) 

            else: 

                raise xs_errors.XenError('LVMWrite', \ 

                      opterr='device %s' % dev) 

 

        if not (dev == rootdev): 

            try: 

                cmd_lvm([CMD_PVCREATE, "-ff", "-y", "--metadatasize", "10M", dev]) 

            except util.CommandException, inst: 

                raise xs_errors.XenError('LVMPartCreate', 

                                         opterr='error is %d' % inst.code) 

 

    # Create VG on first device 

    try: 

        cmd_lvm([CMD_VGCREATE, "--metadatasize", "10M", vgname, rootdev]) 

    except : 

        raise xs_errors.XenError('LVMGroupCreate') 

 

    # Then add any additional devs into the VG 

    for dev in root.split(',')[1:]: 

        try: 

            cmd_lvm([CMD_VGEXTEND, vgname, dev]) 

        except util.CommandException, inst: 

            # One of the PV args failed, delete SR 

            try: 

                cmd_lvm([CMD_VGREMOVE, vgname]) 

            except: 

                pass 

            raise xs_errors.XenError('LVMGroupCreate') 

 

    try: 

        cmd_lvm([CMD_VGCHANGE, "-an", vgname]) 

    except util.CommandException, inst: 

        raise xs_errors.XenError('LVMUnMount', opterr='errno is %d' % inst.code) 

 

    # End block 

 

def removeVG(root, vgname): 

    # Check PVs match VG 

    try: 

        for dev in root.split(','): 

            txt = cmd_lvm([CMD_PVS, dev]) 

            if txt.find(vgname) == -1: 

                raise xs_errors.XenError('LVMNoVolume', \ 

                      opterr='volume is %s' % vgname) 

    except util.CommandException, inst: 

        raise xs_errors.XenError('PVSfailed', \ 

              opterr='error is %d' % inst.code) 

 

    try: 

        cmd_lvm([CMD_VGREMOVE, vgname]) 

 

        for dev in root.split(','): 

            cmd_lvm([CMD_PVREMOVE, dev]) 

    except util.CommandException, inst: 

        raise xs_errors.XenError('LVMDelete', \ 

              opterr='errno is %d' % inst.code) 

 

def resizePV(dev): 

    try: 

        cmd_lvm([CMD_PVRESIZE, dev]) 

    except util.CommandException, inst: 

        util.SMlog("Failed to grow the PV, non-fatal") 

 

def setActiveVG(path, active): 

    "activate or deactivate VG 'path'" 

    val = "n" 

    if active: 

        val = "y" 

    text = cmd_lvm([CMD_VGCHANGE, "-a" + val, path]) 

 

def create(name, size, vgname, tag=None, size_in_percentage=None): 

    if size_in_percentage: 

        cmd = [CMD_LVCREATE, "-n", name, "-l", size_in_percentage, vgname] 

    else: 

        size_mb = size / 1024 / 1024 

        cmd = [CMD_LVCREATE, "-n", name, "-L", str(size_mb), vgname] 

    if tag: 

        cmd.extend(["--addtag", tag]) 

 

    cmd.extend(['-W', 'n']) 

    cmd_lvm(cmd) 

 

def remove(path, config_param=None): 

    # see deactivateNoRefcount() 

560    for i in range(LVM_FAIL_RETRIES): 

        try: 

            _remove(path, config_param) 

            break 

        except util.CommandException, e: 

            if i >= LVM_FAIL_RETRIES - 1: 

                raise 

            util.SMlog("*** lvremove failed on attempt #%d" % i) 

    _lvmBugCleanup(path) 

 

def _remove(path, config_param=None): 

    CONFIG_TAG = "--config" 

    cmd = [CMD_LVREMOVE, "-f", path] 

    if config_param: 

        cmd.extend([CONFIG_TAG, "devices{" + config_param + "}"]) 

    ret = cmd_lvm(cmd) 

 

def rename(path, newName): 

    cmd_lvm([CMD_LVRENAME, path, newName], pread_func=util.pread) 

 

def setReadonly(path, readonly): 

    val = "r" 

    if not readonly: 

        val += "w" 

    ret = cmd_lvm([CMD_LVCHANGE, path, "-p", val], pread_func=util.pread) 

 

def exists(path): 

    (rc, stdout, stderr) = cmd_lvm([CMD_LVS, "--noheadings", path], pread_func=util.doexec) 

    return rc == 0 

 

def setSize(path, size, confirm): 

    sizeMB = size / (1024 * 1024) 

    if confirm: 

        cmd_lvm([CMD_LVRESIZE, "-L", str(sizeMB), path],util.pread3, "y\n") 

    else: 

        cmd_lvm([CMD_LVRESIZE, "-L", str(sizeMB), path], pread_func=util.pread) 

 

def setHidden(path, hidden = True): 

    opt = "--addtag" 

    if not hidden: 

        opt = "--deltag" 

    cmd_lvm([CMD_LVCHANGE, opt, LV_TAG_HIDDEN, path]) 

 

def activateNoRefcount(path, refresh): 

    cmd = [CMD_LVCHANGE, "-ay", path] 

    text = cmd_lvm(cmd) 

    if not _checkActive(path): 

        raise util.CommandException(-1, str(cmd), "LV not activated") 

    if refresh: 

        # Override slave mode lvm.conf for this command 

        os.environ['LVM_SYSTEM_DIR'] = MASTER_LVM_CONF 

        text = cmd_lvm([CMD_LVCHANGE, "--refresh", path]) 

        mapperDevice = path[5:].replace("-", "--").replace("/", "-") 

        cmd = [CMD_DMSETUP, "table", mapperDevice] 

        ret = util.pread(cmd) 

        util.SMlog("DM table for %s: %s" % (path, ret.strip())) 

        # Restore slave mode lvm.conf 

        os.environ['LVM_SYSTEM_DIR'] = DEF_LVM_CONF 

 

def deactivateNoRefcount(path): 

    # LVM has a bug where if an "lvs" command happens to run at the same time  

    # as "lvchange -an", it might hold the device in use and cause "lvchange  

    # -an" to fail. Thus, we need to retry if "lvchange -an" fails. Worse yet,  

    # the race could lead to "lvchange -an" starting to deactivate (removing  

    # the symlink), failing to "dmsetup remove" the device, and still returning   

    # success. Thus, we need to check for the device mapper file existence if  

    # "lvchange -an" returns success.  

    for i in range(LVM_FAIL_RETRIES): 

        try: 

            _deactivate(path) 

            break 

        except util.CommandException: 

            if i >= LVM_FAIL_RETRIES - 1: 

                raise 

            util.SMlog("*** lvchange -an failed on attempt #%d" % i) 

    _lvmBugCleanup(path) 

 

def _deactivate(path): 

    text = cmd_lvm([CMD_LVCHANGE, "-an", path]) 

 

def _checkActive(path): 

    if util.pathexists(path): 

        return True 

 

    util.SMlog("_checkActive: %s does not exist!" % path) 

    symlinkExists = os.path.lexists(path) 

    util.SMlog("_checkActive: symlink exists: %s" % symlinkExists) 

 

    mapperDeviceExists = False 

    mapperDevice = path[5:].replace("-", "--").replace("/", "-") 

    cmd = [CMD_DMSETUP, "status", mapperDevice] 

    try: 

        ret = util.pread2(cmd) 

        mapperDeviceExists = True 

        util.SMlog("_checkActive: %s: %s" % (mapperDevice, ret)) 

    except util.CommandException: 

        util.SMlog("_checkActive: device %s does not exist" % mapperDevice) 

 

    mapperPath = "/dev/mapper/" + mapperDevice 

    mapperPathExists = util.pathexists(mapperPath) 

    util.SMlog("_checkActive: path %s exists: %s" % \ 

            (mapperPath, mapperPathExists)) 

 

    if mapperDeviceExists and mapperPathExists and not symlinkExists: 

        # we can fix this situation manually here 

        try: 

            util.SMlog("_checkActive: attempt to create the symlink manually.") 

            os.symlink(mapperPath, path) 

        except OSError, e: 

            util.SMlog("ERROR: failed to symlink!") 

            if e.errno != errno.EEXIST: 

                raise 

        if util.pathexists(path): 

            util.SMlog("_checkActive: created the symlink manually") 

            return True 

 

    return False 

 

def _lvmBugCleanup(path): 

    # the device should not exist at this point. If it does, this was an LVM  

    # bug, and we manually clean up after LVM here 

    mapperDevice = path[5:].replace("-", "--").replace("/", "-") 

    mapperPath = "/dev/mapper/" + mapperDevice 

 

    nodeExists = False 

    cmd_st = [CMD_DMSETUP, "status", mapperDevice] 

    cmd_rm = [CMD_DMSETUP, "remove", mapperDevice] 

    cmd_rf = [CMD_DMSETUP, "remove", mapperDevice, "--force"] 

 

    try: 

        util.pread(cmd_st, expect_rc=1) 

    except util.CommandException, e: 

687        if e.code == 0: 

            nodeExists = True 

 

688    if not util.pathexists(mapperPath) and not nodeExists: 

        return 

 

    util.SMlog("_lvmBugCleanup: seeing dm file %s" % mapperPath) 

 

    # destroy the dm device 

718    if nodeExists: 

        util.SMlog("_lvmBugCleanup: removing dm device %s" % mapperDevice) 

718        for i in range(LVM_FAIL_RETRIES): 

            try: 

                util.pread2(cmd_rm) 

                break 

            except util.CommandException, e: 

                if i < LVM_FAIL_RETRIES - 1: 

                    util.SMlog("Failed on try %d, retrying" % i) 

                    try: 

                        util.pread(cmd_st, expect_rc=1) 

                        util.SMlog("_lvmBugCleanup: dm device {}" 

                                   " removed".format(mapperDevice) 

                                   ) 

                        break 

                    except: 

                        cmd_rm = cmd_rf 

                        time.sleep(1) 

                else: 

                    # make sure the symlink is still there for consistency 

                    if not os.path.lexists(path): 

                        os.symlink(mapperPath, path) 

                        util.SMlog("_lvmBugCleanup: restored symlink %s" % path) 

                    raise e 

 

719    if util.pathexists(mapperPath): 

        os.unlink(mapperPath) 

        util.SMlog("_lvmBugCleanup: deleted devmapper file %s" % mapperPath) 

 

    # delete the symlink 

724    if os.path.lexists(path): 

        os.unlink(path) 

        util.SMlog("_lvmBugCleanup: deleted symlink %s" % path) 

 

# mdpath is of format /dev/VG-SR-UUID/MGT 

# or in other words /VG_LOCATION/VG_PREFIXSR-UUID/MDVOLUME_NAME 

def ensurePathExists(mdpath): 

    if not os.path.exists(mdpath): 

        vgname = mdpath.split('/')[2] 

        lvmCache = lvmcache.LVMCache(vgname) 

        lvmCache.activateNoRefcount(MDVOLUME_NAME) 

 

def removeDevMapperEntry(path, strict=True): 

    try: 

        # remove devmapper entry using dmsetup 

        cmd = [CMD_DMSETUP, "remove", path] 

        cmd_lvm(cmd) 

        return True 

    except Exception, e: 

        if not strict: 

            cmd = [CMD_DMSETUP, "status", path] 

            try: 

                util.pread(cmd, expect_rc=1) 

                return True 

            except: 

                pass  # Continuining will fail and log the right way 

        ret = util.pread2(["lsof", path]) 

        util.SMlog("removeDevMapperEntry: dmsetup remove failed for file %s " \ 

                   "with error %s, and lsof ret is %s." % (path, str(e), ret)) 

        return False