Index: subversion/include/svn_error_codes.h
===================================================================
--- subversion/include/svn_error_codes.h	(revision 998620)
+++ subversion/include/svn_error_codes.h	(working copy)
@@ -219,6 +219,11 @@
              SVN_ERR_BAD_CATEGORY_START + 13,
              "Unknown string value of token")
 
+  /** @since New in 1.7. */
+  SVN_ERRDEF(SVN_ERR_BAD_OLD_VALUE,
+             SVN_ERR_BAD_CATEGORY_START + 14,
+             "Old value doesn't match repository")
+
   /* xml errors */
 
   SVN_ERRDEF(SVN_ERR_XML_ATTRIB_NOT_FOUND,
Index: subversion/libsvn_fs_fs/fs_fs.c
===================================================================
--- subversion/libsvn_fs_fs/fs_fs.c	(revision 998620)
+++ subversion/libsvn_fs_fs/fs_fs.c	(working copy)
@@ -7312,7 +7312,7 @@
               && !svn_string_compare(wanted_value, present_value)))
         {
           /* What we expected isn't what we found. */
-          return svn_error_createf(SVN_ERR_BAD_PROPERTY_VALUE, NULL,
+          return svn_error_createf(SVN_ERR_BAD_OLD_VALUE, NULL,
                                    _("revprop '%s' has unexpected value in "
                                      "filesystem"),
                                    cb->name);
Index: subversion/libsvn_fs_base/revs-txns.c
===================================================================
--- subversion/libsvn_fs_base/revs-txns.c	(revision 998620)
+++ subversion/libsvn_fs_base/revs-txns.c	(working copy)
@@ -270,7 +270,7 @@
               && !svn_string_compare(wanted_value, present_value)))
         {
           /* What we expected isn't what we found. */
-          return svn_error_createf(SVN_ERR_BAD_PROPERTY_VALUE, NULL,
+          return svn_error_createf(SVN_ERR_BAD_OLD_VALUE, NULL,
                                    _("revprop '%s' has unexpected value in "
                                      "filesystem"),
                                    name);
Index: subversion/include/svn_fs.h
===================================================================
--- subversion/include/svn_fs.h	(revision 998620)
+++ subversion/include/svn_fs.h	(working copy)
@@ -1896,8 +1896,8 @@
  * - @a name is the name of the property to change.
  * - if @a old_value_p is not @c NULL, then @a *old_value_p is the expected old
  *   value of the property, and changing the value will fail with error
- *   #SVN_ERR_BAD_PROPERTY_VALUE if the present value of the property is not @a
- *   *old_value_p.
+ *   #SVN_ERR_BAD_OLD_VALUE if the present value of the property is not @a
+ *   *old_value_p.  (This is an atomic test-and-set).
  * - @a value is the new value of the property, or zero if the property should
  *   be removed altogether.
  *
Index: subversion/tests/libsvn_fs/fs-test.c
===================================================================
--- subversion/tests/libsvn_fs/fs-test.c	(revision 998620)
+++ subversion/tests/libsvn_fs/fs-test.c	(working copy)
@@ -586,12 +586,12 @@
 }
 
 
-/* If EXPR raises SVN_ERR_BAD_PROPERTY_VALUE, continue; else, fail
+/* If EXPR raises SVN_ERR_BAD_OLD_VALUE, continue; else, fail
  * the test. */
-#define FAILS_WITH_BPV(expr) \
+#define FAILS_WITH_BOV(expr) \
   do { \
       svn_error_t *__err = (expr); \
-      if (!__err || __err->apr_err != SVN_ERR_BAD_PROPERTY_VALUE) \
+      if (!__err || __err->apr_err != SVN_ERR_BAD_OLD_VALUE) \
         return svn_error_create(SVN_ERR_TEST_FAILED, __err, \
                                 "svn_fs_change_rev_prop2() failed to " \
                                 "detect unexpected old value"); \
@@ -662,18 +662,18 @@
 
       /* Value of "flower" is 's1'. */
 
-      FAILS_WITH_BPV(svn_fs_change_rev_prop2(fs, 0, "flower", &s2_p, s1_p, pool));
+      FAILS_WITH_BOV(svn_fs_change_rev_prop2(fs, 0, "flower", &s2_p, s1_p, pool));
       s1_dup = svn_string_dup(&s1, pool);
       SVN_ERR(svn_fs_change_rev_prop2(fs, 0, "flower", &s1_dup, s2_p, pool));
 
       /* Value of "flower" is 's2'. */
 
-      FAILS_WITH_BPV(svn_fs_change_rev_prop2(fs, 0, "flower", &s1_p, NULL, pool));
+      FAILS_WITH_BOV(svn_fs_change_rev_prop2(fs, 0, "flower", &s1_p, NULL, pool));
       SVN_ERR(svn_fs_change_rev_prop2(fs, 0, "flower", &s2_p, NULL, pool));
 
       /* Value of "flower" is <not set>. */
 
-      FAILS_WITH_BPV(svn_fs_change_rev_prop2(fs, 0, "flower", &s2_p, s1_p, pool));
+      FAILS_WITH_BOV(svn_fs_change_rev_prop2(fs, 0, "flower", &s2_p, s1_p, pool));
       SVN_ERR(svn_fs_change_rev_prop2(fs, 0, "flower", &unset, s1_p, pool));
 
       /* Value of "flower" is 's1'. */