rgw: add support for max_meta_name_length of Swift API's /info.

Fixes: http://tracker.ceph.com/issues/17938
Signed-off-by: Radoslaw Zarzynski <rzarzynski@mirantis.com>

src/rgw/rgw_file.cc

@@ -1452,7 +1452,10 @@ namespace rgw {
       attrbl.append(val.c_str(), val.size() + 1);
     }
 
-    rgw_get_request_metadata(s->cct, s->info, attrs);
+    op_ret = rgw_get_request_metadata(s->cct, s->info, attrs);
+    if (op_ret < 0) {
+      goto done;
+    }
     encode_delete_at_attr(delete_at, attrs);
 
     /* Add a custom metadata to expose the information whether an object

src/rgw/rgw_op.cc

@@ -2652,7 +2652,10 @@ void RGWCreateBucket::execute()
   if (need_metadata_upload()) {
     /* It's supposed that following functions WILL NOT change any special
      * attributes (like RGW_ATTR_ACL) if they are already present in attrs. */
-    rgw_get_request_metadata(s->cct, s->info, attrs, false);
+    op_ret = rgw_get_request_metadata(s->cct, s->info, attrs, false);
+    if (op_ret < 0) {
+      return;
+    }
     prepare_add_del_attrs(s->bucket_attrs, rmattr_names, attrs);
     populate_with_generic_attrs(s, attrs);
 
@@ -2745,7 +2748,10 @@ void RGWCreateBucket::execute()
 
       attrs.clear();
 
-      rgw_get_request_metadata(s->cct, s->info, attrs, false);
+      op_ret = rgw_get_request_metadata(s->cct, s->info, attrs, false);
+      if (op_ret < 0) {
+        return;
+      }
       prepare_add_del_attrs(s->bucket_attrs, rmattr_names, attrs);
       populate_with_generic_attrs(s, attrs);
       op_ret = filter_out_quota_info(attrs, rmattr_names, s->bucket_info.quota);
@@ -3543,7 +3549,10 @@ void RGWPutObj::execute()
   emplace_attr(RGW_ATTR_ETAG, std::move(bl));
 
   populate_with_generic_attrs(s, attrs);
-  rgw_get_request_metadata(s->cct, s->info, attrs);
+  op_ret = rgw_get_request_metadata(s->cct, s->info, attrs);
+  if (op_ret < 0) {
+    goto done;
+  }
   encode_delete_at_attr(delete_at, attrs);
   encode_obj_tags_attr(obj_tags.get(), attrs);
 
@@ -3857,7 +3866,10 @@ int RGWPutMetadataAccount::init_processing()
     attrs.emplace(RGW_ATTR_ACL, std::move(acl_bl));
   }
 
-  rgw_get_request_metadata(s->cct, s->info, attrs, false);
+  op_ret = rgw_get_request_metadata(s->cct, s->info, attrs, false);
+  if (op_ret < 0) {
+    return op_ret;
+  }
   prepare_add_del_attrs(orig_attrs, rmattr_names, attrs);
   populate_with_generic_attrs(s, attrs);
 
@@ -3949,7 +3961,10 @@ void RGWPutMetadataBucket::execute()
     return;
   }
 
-  rgw_get_request_metadata(s->cct, s->info, attrs, false);
+  op_ret = rgw_get_request_metadata(s->cct, s->info, attrs, false);
+  if (op_ret < 0) {
+    return;
+  }
 
   if (!placement_rule.empty() &&
       placement_rule != s->bucket_info.placement_rule) {
@@ -4036,7 +4051,11 @@ void RGWPutMetadataObject::execute()
     return;
   }
 
-  rgw_get_request_metadata(s->cct, s->info, attrs);
+  op_ret = rgw_get_request_metadata(s->cct, s->info, attrs);
+  if (op_ret < 0) {
+    return;
+  }
+
   /* check if obj exists, read orig attrs */
   op_ret = get_obj_attrs(store, s, obj, orig_attrs);
   if (op_ret < 0) {
@@ -4410,7 +4429,10 @@ int RGWCopyObj::init_common()
   dest_policy.encode(aclbl);
   emplace_attr(RGW_ATTR_ACL, std::move(aclbl));
 
-  rgw_get_request_metadata(s->cct, s->info, attrs);
+  op_ret = rgw_get_request_metadata(s->cct, s->info, attrs);
+  if (op_ret < 0) {
+    return op_ret;
+  }
   populate_with_generic_attrs(s, attrs);
 
   return 0;
@@ -5114,7 +5136,10 @@ void RGWInitMultipart::execute()
   if (op_ret != 0)
     return;
 
-  rgw_get_request_metadata(s->cct, s->info, attrs);
+  op_ret = rgw_get_request_metadata(s->cct, s->info, attrs);
+  if (op_ret < 0) {
+    return;
+  }
 
   do {
     char buf[33];

src/rgw/rgw_op.h

@@ -1884,12 +1884,14 @@ static inline void format_xattr(std::string &xattr)
  * map(<attr_name, attr_contents>, where attr_name is RGW_ATTR_PREFIX.HTTP_NAME)
  * s: The request state
  * attrs: will be filled up with attrs mapped as <attr_name, attr_contents>
+ * On success returns 0.
+ * On failure returns a negative error code.
  *
  */
-static inline void rgw_get_request_metadata(CephContext *cct,
-					    struct req_info& info,
-					    map<string, bufferlist>& attrs,
-					    const bool allow_empty_attrs = true)
+static inline int rgw_get_request_metadata(CephContext* const cct,
+                                           struct req_info& info,
+                                           std::map<std::string, ceph::bufferlist>& attrs,
+                                           const bool allow_empty_attrs = true)
 {
   static const std::set<std::string> blacklisted_headers = {
       "x-amz-server-side-encryption-customer-algorithm",
@@ -1909,13 +1911,25 @@ static inline void rgw_get_request_metadata(CephContext *cct,
       format_xattr(xattr);
       string attr_name(RGW_ATTR_PREFIX);
       attr_name.append(name);
+
+      /* Check early whether we aren't going behind the limit on attribute
+       * name. Passing here doesn't guarantee that an OSD will accept that
+       * as ObjectStore::get_max_attr_name_length() can set the limit even
+       * lower. However, we're claiming "max_meta_name_length" in /info as
+       * being dependent on the "osd_max_attr_name_len".  */
+      if (attr_name.length() > cct->_conf->osd_max_attr_name_len) {
+        return -ENAMETOOLONG;
+      }
+
       map<string, bufferlist>::value_type v(attr_name, bufferlist());
       std::pair < map<string, bufferlist>::iterator, bool >
 	rval(attrs.insert(v));
       bufferlist& bl(rval.first->second);
       bl.append(xattr.c_str(), xattr.size() + 1);
     }
   }
+
+  return 0;
 } /* rgw_get_request_metadata */
 
 static inline void encode_delete_at_attr(boost::optional<ceph::real_time> delete_at,

src/rgw/rgw_rest_swift.cc

@@ -1661,7 +1661,10 @@ void RGWInfo_ObjStore_SWIFT::list_swift_data(Formatter& formatter,
 
   string ceph_version(CEPH_GIT_NICE_VER);
   formatter.dump_string("version", ceph_version);
-  formatter.dump_int("max_meta_name_length", 81);
+
+  const size_t meta_name_limit = g_conf->osd_max_attr_name_len
+    - strlen(RGW_ATTR_PREFIX RGW_AMZ_META_PREFIX);
+  formatter.dump_int("max_meta_name_length", meta_name_limit);
 
   formatter.open_array_section("policies");
   RGWZoneGroup& zonegroup = store.get_zonegroup();