src/allmydata/mutable/checker.py

   1
   2 from twisted.internet import defer
   3 from twisted.python import failure
   4 from allmydata import hashtree
   5 from allmydata.uri import from_string
   6 from allmydata.util import hashutil, base32, idlib, log
   7 from allmydata.check_results import CheckAndRepairResults, CheckResults
   8
   9 from common import MODE_CHECK, CorruptShareError
  10 from servermap import ServerMap, ServermapUpdater
  11 from layout import unpack_share, SIGNED_PREFIX_LENGTH
  12
  13 class MutableChecker:
  14
  15     def __init__(self, node, monitor):
  16         self._node = node
  17         self._monitor = monitor
  18         self.bad_shares = [] # list of (nodeid,shnum,failure)
  19         self._storage_index = self._node.get_storage_index()
  20         self.results = CheckResults(from_string(node.get_uri()), self._storage_index)
  21         self.need_repair = False
  22         self.responded = set() # set of (binary) nodeids
  23
  24     def check(self, verify=False, add_lease=False):
  25         servermap = ServerMap()
  26         u = ServermapUpdater(self._node, self._monitor, servermap, MODE_CHECK,
  27                              add_lease=add_lease)
  28         history = self._node._client.get_history()
  29         if history:
  30             history.notify_mapupdate(u.get_status())
  31         d = u.update()
  32         d.addCallback(self._got_mapupdate_results)
  33         if verify:
  34             d.addCallback(self._verify_all_shares)
  35         d.addCallback(lambda res: servermap)
  36         d.addCallback(self._fill_checker_results, self.results)
  37         d.addCallback(lambda res: self.results)
  38         return d
  39
  40     def _got_mapupdate_results(self, servermap):
  41         # the file is healthy if there is exactly one recoverable version, it
  42         # has at least N distinct shares, and there are no unrecoverable
  43         # versions: all existing shares will be for the same version.
  44         self._monitor.raise_if_cancelled()
  45         self.best_version = None
  46         num_recoverable = len(servermap.recoverable_versions())
  47         if num_recoverable:
  48             self.best_version = servermap.best_recoverable_version()
  49
  50         if servermap.unrecoverable_versions():
  51             self.need_repair = True
  52         if num_recoverable != 1:
  53             self.need_repair = True
  54         if self.best_version:
  55             available_shares = servermap.shares_available()
  56             (num_distinct_shares, k, N) = available_shares[self.best_version]
  57             if num_distinct_shares < N:
  58                 self.need_repair = True
  59
  60         return servermap
  61
  62     def _verify_all_shares(self, servermap):
  63         # read every byte of each share
  64         if not self.best_version:
  65             return
  66         versionmap = servermap.make_versionmap()
  67         shares = versionmap[self.best_version]
  68         (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
  69          offsets_tuple) = self.best_version
  70         offsets = dict(offsets_tuple)
  71         readv = [ (0, offsets["EOF"]) ]
  72         dl = []
  73         for (shnum, peerid, timestamp) in shares:
  74             ss = servermap.connections[peerid]
  75             d = self._do_read(ss, peerid, self._storage_index, [shnum], readv)
  76             d.addCallback(self._got_answer, peerid, servermap)
  77             dl.append(d)
  78         return defer.DeferredList(dl, fireOnOneErrback=True, consumeErrors=True)
  79
  80     def _do_read(self, ss, peerid, storage_index, shnums, readv):
  81         # isolate the callRemote to a separate method, so tests can subclass
  82         # Publish and override it
  83         d = ss.callRemote("slot_readv", storage_index, shnums, readv)
  84         return d
  85
  86     def _got_answer(self, datavs, peerid, servermap):
  87         for shnum,datav in datavs.items():
  88             data = datav[0]
  89             try:
  90                 self._got_results_one_share(shnum, peerid, data)
  91             except CorruptShareError:
  92                 f = failure.Failure()
  93                 self.need_repair = True
  94                 self.bad_shares.append( (peerid, shnum, f) )
  95                 prefix = data[:SIGNED_PREFIX_LENGTH]
  96                 servermap.mark_bad_share(peerid, shnum, prefix)
  97                 ss = servermap.connections[peerid]
  98                 self.notify_server_corruption(ss, shnum, str(f.value))
  99
 100     def check_prefix(self, peerid, shnum, data):
 101         (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 102          offsets_tuple) = self.best_version
 103         got_prefix = data[:SIGNED_PREFIX_LENGTH]
 104         if got_prefix != prefix:
 105             raise CorruptShareError(peerid, shnum,
 106                                     "prefix mismatch: share changed while we were reading it")
 107
 108     def _got_results_one_share(self, shnum, peerid, data):
 109         self.check_prefix(peerid, shnum, data)
 110
 111         # the [seqnum:signature] pieces are validated by _compare_prefix,
 112         # which checks their signature against the pubkey known to be
 113         # associated with this file.
 114
 115         (seqnum, root_hash, IV, k, N, segsize, datalen, pubkey, signature,
 116          share_hash_chain, block_hash_tree, share_data,
 117          enc_privkey) = unpack_share(data)
 118
 119         # validate [share_hash_chain,block_hash_tree,share_data]
 120
 121         leaves = [hashutil.block_hash(share_data)]
 122         t = hashtree.HashTree(leaves)
 123         if list(t) != block_hash_tree:
 124             raise CorruptShareError(peerid, shnum, "block hash tree failure")
 125         share_hash_leaf = t[0]
 126         t2 = hashtree.IncompleteHashTree(N)
 127         # root_hash was checked by the signature
 128         t2.set_hashes({0: root_hash})
 129         try:
 130             t2.set_hashes(hashes=share_hash_chain,
 131                           leaves={shnum: share_hash_leaf})
 132         except (hashtree.BadHashError, hashtree.NotEnoughHashesError,
 133                 IndexError), e:
 134             msg = "corrupt hashes: %s" % (e,)
 135             raise CorruptShareError(peerid, shnum, msg)
 136
 137         # validate enc_privkey: only possible if we have a write-cap
 138         if not self._node.is_readonly():
 139             alleged_privkey_s = self._node._decrypt_privkey(enc_privkey)
 140             alleged_writekey = hashutil.ssk_writekey_hash(alleged_privkey_s)
 141             if alleged_writekey != self._node.get_writekey():
 142                 raise CorruptShareError(peerid, shnum, "invalid privkey")
 143
 144     def notify_server_corruption(self, ss, shnum, reason):
 145         ss.callRemoteOnly("advise_corrupt_share",
 146                           "mutable", self._storage_index, shnum, reason)
 147
 148     def _count_shares(self, smap, version):
 149         available_shares = smap.shares_available()
 150         (num_distinct_shares, k, N) = available_shares[version]
 151         counters = {}
 152         counters["count-shares-good"] = num_distinct_shares
 153         counters["count-shares-needed"] = k
 154         counters["count-shares-expected"] = N
 155         good_hosts = smap.all_peers_for_version(version)
 156         counters["count-good-share-hosts"] = len(good_hosts)
 157         vmap = smap.make_versionmap()
 158         counters["count-wrong-shares"] = sum([len(shares)
 159                                           for verinfo,shares in vmap.items()
 160                                           if verinfo != version])
 161
 162         return counters
 163
 164     def _fill_checker_results(self, smap, r):
 165         self._monitor.raise_if_cancelled()
 166         r.set_servermap(smap.copy())
 167         healthy = True
 168         data = {}
 169         report = []
 170         summary = []
 171         vmap = smap.make_versionmap()
 172         recoverable = smap.recoverable_versions()
 173         unrecoverable = smap.unrecoverable_versions()
 174         data["count-recoverable-versions"] = len(recoverable)
 175         data["count-unrecoverable-versions"] = len(unrecoverable)
 176
 177         if recoverable:
 178             report.append("Recoverable Versions: " +
 179                           "/".join(["%d*%s" % (len(vmap[v]),
 180                                                smap.summarize_version(v))
 181                                     for v in recoverable]))
 182         if unrecoverable:
 183             report.append("Unrecoverable Versions: " +
 184                           "/".join(["%d*%s" % (len(vmap[v]),
 185                                                smap.summarize_version(v))
 186                                     for v in unrecoverable]))
 187         if smap.unrecoverable_versions():
 188             healthy = False
 189             summary.append("some versions are unrecoverable")
 190             report.append("Unhealthy: some versions are unrecoverable")
 191         if len(recoverable) == 0:
 192             healthy = False
 193             summary.append("no versions are recoverable")
 194             report.append("Unhealthy: no versions are recoverable")
 195         if len(recoverable) > 1:
 196             healthy = False
 197             summary.append("multiple versions are recoverable")
 198             report.append("Unhealthy: there are multiple recoverable versions")
 199
 200         needs_rebalancing = False
 201         if recoverable:
 202             best_version = smap.best_recoverable_version()
 203             report.append("Best Recoverable Version: " +
 204                           smap.summarize_version(best_version))
 205             counters = self._count_shares(smap, best_version)
 206             data.update(counters)
 207             s = counters["count-shares-good"]
 208             k = counters["count-shares-needed"]
 209             N = counters["count-shares-expected"]
 210             if s < N:
 211                 healthy = False
 212                 report.append("Unhealthy: best version has only %d shares "
 213                               "(encoding is %d-of-%d)" % (s, k, N))
 214                 summary.append("%d shares (enc %d-of-%d)" % (s, k, N))
 215             hosts = smap.all_peers_for_version(best_version)
 216             needs_rebalancing = bool( len(hosts) < N )
 217         elif unrecoverable:
 218             healthy = False
 219             # find a k and N from somewhere
 220             first = list(unrecoverable)[0]
 221             # not exactly the best version, but that doesn't matter too much
 222             data.update(self._count_shares(smap, first))
 223             # leave needs_rebalancing=False: the file being unrecoverable is
 224             # the bigger problem
 225         else:
 226             # couldn't find anything at all
 227             data["count-shares-good"] = 0
 228             data["count-shares-needed"] = 3 # arbitrary defaults
 229             data["count-shares-expected"] = 10
 230             data["count-good-share-hosts"] = 0
 231             data["count-wrong-shares"] = 0
 232
 233         if self.bad_shares:
 234             data["count-corrupt-shares"] = len(self.bad_shares)
 235             data["list-corrupt-shares"] = locators = []
 236             report.append("Corrupt Shares:")
 237             summary.append("Corrupt Shares:")
 238             for (peerid, shnum, f) in sorted(self.bad_shares):
 239                 locators.append( (peerid, self._storage_index, shnum) )
 240                 s = "%s-sh%d" % (idlib.shortnodeid_b2a(peerid), shnum)
 241                 if f.check(CorruptShareError):
 242                     ft = f.value.reason
 243                 else:
 244                     ft = str(f)
 245                 report.append(" %s: %s" % (s, ft))
 246                 summary.append(s)
 247                 p = (peerid, self._storage_index, shnum, f)
 248                 r.problems.append(p)
 249                 msg = ("CorruptShareError during mutable verify, "
 250                        "peerid=%(peerid)s, si=%(si)s, shnum=%(shnum)d, "
 251                        "where=%(where)s")
 252                 log.msg(format=msg, peerid=idlib.nodeid_b2a(peerid),
 253                         si=base32.b2a(self._storage_index),
 254                         shnum=shnum,
 255                         where=ft,
 256                         level=log.WEIRD, umid="EkK8QA")
 257         else:
 258             data["count-corrupt-shares"] = 0
 259             data["list-corrupt-shares"] = []
 260
 261         sharemap = {}
 262         for verinfo in vmap:
 263             for (shnum, peerid, timestamp) in vmap[verinfo]:
 264                 shareid = "%s-sh%d" % (smap.summarize_version(verinfo), shnum)
 265                 if shareid not in sharemap:
 266                     sharemap[shareid] = []
 267                 sharemap[shareid].append(peerid)
 268         data["sharemap"] = sharemap
 269         data["servers-responding"] = list(smap.reachable_peers)
 270
 271         r.set_healthy(healthy)
 272         r.set_recoverable(bool(recoverable))
 273         r.set_needs_rebalancing(needs_rebalancing)
 274         r.set_data(data)
 275         if healthy:
 276             r.set_summary("Healthy")
 277         else:
 278             r.set_summary("Unhealthy: " + " ".join(summary))
 279         r.set_report(report)
 280
 281
 282 class MutableCheckAndRepairer(MutableChecker):
 283     def __init__(self, node, monitor):
 284         MutableChecker.__init__(self, node, monitor)
 285         self.cr_results = CheckAndRepairResults(self._storage_index)
 286         self.cr_results.pre_repair_results = self.results
 287         self.need_repair = False
 288
 289     def check(self, verify=False, add_lease=False):
 290         d = MutableChecker.check(self, verify, add_lease)
 291         d.addCallback(self._maybe_repair)
 292         d.addCallback(lambda res: self.cr_results)
 293         return d
 294
 295     def _maybe_repair(self, res):
 296         self._monitor.raise_if_cancelled()
 297         if not self.need_repair:
 298             self.cr_results.post_repair_results = self.results
 299             return
 300         if self._node.is_readonly():
 301             # ticket #625: we cannot yet repair read-only mutable files
 302             self.cr_results.post_repair_results = self.results
 303             self.cr_results.repair_attempted = False
 304             return
 305         self.cr_results.repair_attempted = True
 306         d = self._node.repair(self.results)
 307         def _repair_finished(repair_results):
 308             self.cr_results.repair_successful = True
 309             r = CheckResults(from_string(self._node.get_uri()), self._storage_index)
 310             self.cr_results.post_repair_results = r
 311             self._fill_checker_results(repair_results.servermap, r)
 312             self.cr_results.repair_results = repair_results # TODO?
 313         def _repair_error(f):
 314             # I'm not sure if I want to pass through a failure or not.
 315             self.cr_results.repair_successful = False
 316             self.cr_results.repair_failure = f # TODO?
 317             #self.cr_results.post_repair_results = ??
 318             return f
 319         d.addCallbacks(_repair_finished, _repair_error)
 320         return d