From: Sage Weil <sage@inktank.com>
Date: Tue, 28 Jan 2014 18:26:12 +0000 (-0800)
Subject: buffer: make 0-length splice() a no-op
X-Git-Tag: v0.67.6~32
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=2528186c0dd327607b1e76a51581df72aeea52f2;p=ceph.git

buffer: make 0-length splice() a no-op

This was causing a problem in the Striper, but fixing it here will avoid
corner cases all over the tree.  Note that we have to bail out before
the end-of-buffer check to avoid hitting that check when the bufferlist is
also empty.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>
(cherry picked from commit ff5abfbdae07ae8a56fa83ebaa92000896f793c2)
---

diff --git a/src/common/buffer.cc b/src/common/buffer.cc
index 0424887139e9..a32990c57d44 100644
--- a/src/common/buffer.cc
+++ b/src/common/buffer.cc
@@ -1039,6 +1039,9 @@ void buffer::list::rebuild_page_aligned()
   // funky modifer
   void buffer::list::splice(unsigned off, unsigned len, list *claim_by /*, bufferlist& replace_with */)
   {    // fixme?
+    if (len == 0)
+      return;
+
     if (off >= length())
       throw end_of_buffer();
 
diff --git a/src/test/bufferlist.cc b/src/test/bufferlist.cc
index b23bd33e55a4..04374d91cad1 100644
--- a/src/test/bufferlist.cc
+++ b/src/test/bufferlist.cc
@@ -1520,7 +1520,7 @@ TEST(BufferList, splice) {
     bl.push_back(ptr);
   }
   EXPECT_EQ((unsigned)4, bl.buffers().size());
-  EXPECT_THROW(bl.splice(0, 0), FailedAssertion);
+  bl.splice(0, 0);
 
   bufferlist other;
   other.append('X');