From: david-sarah <david-sarah@jacaranda.org>
Date: Fri, 22 Jun 2012 15:43:54 +0000 (+0000)
Subject: Change the maximum mutable share size to 69105 TB, and add a maximum-mutable-share... 
X-Git-Url: https://git.rkrishnan.org/components/%22news.html/frontends/using.html?a=commitdiff_plain;h=33e2d2962e2bc6ccf0f8619d5ea67baee1aebde1;p=tahoe-lafs%2Ftahoe-lafs.git

Change the maximum mutable share size to 69105 TB, and add a maximum-mutable-share-size field to the version announcement. Includes a test. refs #1778
---

diff --git a/src/allmydata/mutable/layout.py b/src/allmydata/mutable/layout.py
index e319e2c5..33d647b9 100644
--- a/src/allmydata/mutable/layout.py
+++ b/src/allmydata/mutable/layout.py
@@ -71,6 +71,8 @@ HEADER_LENGTH = struct.calcsize(HEADER)
 OFFSETS = ">LLLLQQ"
 OFFSETS_LENGTH = struct.calcsize(OFFSETS)
 
+MAX_MUTABLE_SHARE_SIZE = 69105*1000*1000*1000*1000 # 69105 TB, kind of arbitrary
+
 
 # These are still used for some tests of SDMF files.
 def unpack_header(data):
diff --git a/src/allmydata/storage/mutable.py b/src/allmydata/storage/mutable.py
index dc057db4..1f95e515 100644
--- a/src/allmydata/storage/mutable.py
+++ b/src/allmydata/storage/mutable.py
@@ -7,6 +7,8 @@ from allmydata.util.hashutil import constant_time_compare
 from allmydata.storage.lease import LeaseInfo
 from allmydata.storage.common import UnknownMutableContainerVersionError, \
      DataTooLargeError
+from allmydata.mutable.layout import MAX_MUTABLE_SHARE_SIZE
+
 
 # the MutableShareFile is like the ShareFile, but used for mutable data. It
 # has a different layout. See docs/mutable.txt for more details.
@@ -48,7 +50,7 @@ class MutableShareFile:
     # like a sharefile.
     MAGIC = "Tahoe mutable container v1\n" + "\x75\x09\x44\x03\x8e"
     assert len(MAGIC) == 32
-    MAX_SIZE = 2*1000*1000*1000 # 2GB, kind of arbitrary
+    MAX_SIZE = MAX_MUTABLE_SHARE_SIZE
     # TODO: decide upon a policy for max share size
 
     def __init__(self, filename, parent=None):
diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index c5e5b392..9c0397c0 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -13,6 +13,7 @@ _pyflakes_hush = [si_b2a, si_a2b, storage_index_to_dir] # re-exported
 from allmydata.storage.lease import LeaseInfo
 from allmydata.storage.mutable import MutableShareFile, EmptyShare, \
      create_mutable_sharefile
+from allmydata.mutable.layout import MAX_MUTABLE_SHARE_SIZE
 from allmydata.storage.immutable import ShareFile, BucketWriter, BucketReader
 from allmydata.storage.crawler import BucketCountingCrawler
 from allmydata.storage.expirer import LeaseCheckingCrawler
@@ -225,6 +226,7 @@ class StorageServer(service.MultiService, Referenceable):
 
         version = { "http://allmydata.org/tahoe/protocols/storage/v1" :
                     { "maximum-immutable-share-size": remaining_space,
+                      "maximum-mutable-share-size": MAX_MUTABLE_SHARE_SIZE,
                       "tolerates-immutable-read-overrun": True,
                       "delete-mutable-shares-with-zero-length-writev": True,
                       "fills-holes-with-zero-bytes": True,
diff --git a/src/allmydata/storage_client.py b/src/allmydata/storage_client.py
index b536c674..4390baba 100644
--- a/src/allmydata/storage_client.py
+++ b/src/allmydata/storage_client.py
@@ -179,6 +179,7 @@ class NativeStorageServer:
     VERSION_DEFAULTS = {
         "http://allmydata.org/tahoe/protocols/storage/v1" :
         { "maximum-immutable-share-size": 2**32,
+          "maximum-mutable-share-size": 2*1000*1000*1000, # maximum prior to v1.9.2
           "tolerates-immutable-read-overrun": False,
           "delete-mutable-shares-with-zero-length-writev": False,
           },
diff --git a/src/allmydata/test/test_storage.py b/src/allmydata/test/test_storage.py
index d51180d2..08c513cd 100644
--- a/src/allmydata/test/test_storage.py
+++ b/src/allmydata/test/test_storage.py
@@ -325,6 +325,13 @@ class Server(unittest.TestCase):
         sv1 = ver['http://allmydata.org/tahoe/protocols/storage/v1']
         self.failUnless(sv1.get('prevents-read-past-end-of-share-data'), sv1)
 
+    def test_declares_maximum_share_sizes(self):
+        ss = self.create("test_declares_maximum_share_sizes")
+        ver = ss.remote_get_version()
+        sv1 = ver['http://allmydata.org/tahoe/protocols/storage/v1']
+        self.failUnlessIn('maximum-immutable-share-size', sv1)
+        self.failUnlessIn('maximum-mutable-share-size', sv1)
+
     def allocate(self, ss, storage_index, sharenums, size, canary=None):
         renew_secret = hashutil.tagged_hash("blah", "%d" % self._lease_secret.next())
         cancel_secret = hashutil.tagged_hash("blah", "%d" % self._lease_secret.next())