pkgs/core/pomona/src/storage/devicelibs/lvm.py

   1 #!/usr/bin/python
   2
   3 import os
   4 import re
   5
   6 import util
   7
   8 MAX_LV_SLOTS = 256
   9
  10 def has_lvm():
  11     has_lvm = False
  12     for path in os.environ["PATH"].split(":"):
  13         if os.access("%s/lvm" % path, os.X_OK):
  14             has_lvm = True
  15             break
  16
  17     if has_lvm:
  18         has_lvm = False
  19         for line in open("/proc/devices").readlines():
  20             if "device-mapper" in line.split():
  21                 has_lvm = True
  22                 break
  23
  24     return has_lvm
  25
  26 # Start config_args handling code
  27 #
  28 # Theoretically we can handle all that can be handled with the LVM --config
  29 # argument.  For every time we call an lvm_cc (lvm compose config) funciton
  30 # we regenerate the config_args with all global info.
  31 config_args = [] # Holds the final argument list
  32 config_args_data = { "filterRejects": [],    # regular expressions to reject.
  33                             "filterAccepts": [] }   # regexp to accept
  34
  35 def _composeConfig():
  36     """lvm command accepts lvm.conf type arguments preceded by --config. """
  37     global config_args, config_args_data
  38     config_args = []
  39
  40     filter_string = ""
  41     rejects = config_args_data["filterRejects"]
  42     # we don't need the accept for now.
  43     # accepts = config_args_data["filterAccepts"]
  44     # if len(accepts) > 0:
  45     #   for i in range(len(rejects)):
  46     #       filter_string = filter_string + ("\"a|%s|\", " % accpets[i])
  47
  48     if len(rejects) > 0:
  49         for i in range(len(rejects)):
  50             filter_string = filter_string + ("\"r|%s|\"," % rejects[i])
  51
  52     filter_string = " filter=[%s] " % filter_string.strip(",")
  53
  54     # As we add config strings we should check them all.
  55     if filter_string == "":
  56         # Nothing was really done.
  57         return
  58
  59     # devices_string can have (inside the brackets) "dir", "scan",
  60     # "preferred_names", "filter", "cache_dir", "write_cache_state",
  61     # "types", "sysfs_scan", "md_component_detection".  see man lvm.conf.
  62     devices_string = " devices {%s} " % (filter_string) # strings can be added
  63     config_string = devices_string # more strings can be added.
  64     config_args = ["--config", config_string]
  65
  66 def lvm_cc_addFilterRejectRegexp(regexp):
  67     """ Add a regular expression to the --config string."""
  68     global config_args_data
  69     config_args_data["filterRejects"].append(regexp)
  70
  71     # compoes config once more.
  72     _composeConfig()
  73
  74 def lvm_cc_resetFilter():
  75     global config_args_data
  76     config_args_data["filterRejects"] = []
  77     config_args_data["filterAccepts"] = []
  78 # End config_args handling code.
  79
  80 # Names that should not be used int the creation of VGs
  81 lvm_vg_blacklist = []
  82 def blacklistVG(name):
  83     global lvm_vg_blacklist
  84     lvm_vg_blacklist.append(name)
  85
  86 def getPossiblePhysicalExtents(floor=0):
  87     """Returns a list of integers representing the possible values for
  88        the physical extent of a volume group.  Value is in KB.
  89
  90        floor - size (in KB) of smallest PE we care about.
  91     """
  92
  93     possiblePE = []
  94     curpe = 8
  95     while curpe <= 16384*1024:
  96         if curpe >= floor:
  97             possiblePE.append(curpe)
  98         curpe = curpe * 2
  99
 100     return possiblePE
 101
 102 def getMaxLVSize():
 103     """ Return the maximum size (in MB) of a logical volume. """
 104     if util.getArch() in ("x86_64",): #64bit architectures
 105         return (8*1024*1024*1024*1024) #Max is 8EiB (very large number..)
 106     else:
 107         return (16*1024*1024) #Max is 16TiB
 108
 109 def safeLvmName(name):
 110     tmp = name.strip()
 111     tmp = tmp.replace("/", "_")
 112     tmp = re.sub("[^0-9a-zA-Z._]", "", tmp)
 113     tmp = tmp.lstrip("_")
 114
 115     return tmp