From b52bfe6b443f0ff88c8614441752102058063699 Mon Sep 17 00:00:00 2001
From: Ning Yao <yaoning@unitedstack.com>
Date: Thu, 6 Apr 2017 11:12:04 +0000
Subject: [PATCH] os/filestore: fix infinit loops in fiemap()

since fiemap can get extents based on offset --> len
but we should consider last extents is retrieved when len == 0
even though it is not last fiemap extents

Signed-off-by: Ning Yao <yaoning@unitedstack.com>
(cherry picked from commit 36f6b668a8910d76847674086cbc86910c78faee)
---
 src/os/filestore/FileStore.cc      | 13 +++++--------
 src/test/objectstore/store_test.cc | 21 +++++++++++++++++++++
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/os/filestore/FileStore.cc b/src/os/filestore/FileStore.cc
index c47b0d0d2eae..95f48cdf4960 100644
--- a/src/os/filestore/FileStore.cc
+++ b/src/os/filestore/FileStore.cc
@@ -3102,17 +3102,14 @@ int FileStore::_do_fiemap(int fd, uint64_t offset, size_t len,
     i++;
     last = extent++;
   }
-  const bool is_last = last->fe_flags & FIEMAP_EXTENT_LAST;
+  uint64_t xoffset = last->fe_logical + last->fe_length - offset;
+  offset = last->fe_logical + last->fe_length;
+  len -= xoffset;
+  const bool is_last = (last->fe_flags & FIEMAP_EXTENT_LAST) || (len == 0);
+  free(fiemap);
   if (!is_last) {
-    uint64_t xoffset = last->fe_logical + last->fe_length - offset;
-    offset = last->fe_logical + last->fe_length;
-    len -= xoffset;
-    free(fiemap); /* fix clang warn: use-after-free */
     goto more;
   }
-  else {
-    free(fiemap);
-  }
 
   return r;
 }
diff --git a/src/test/objectstore/store_test.cc b/src/test/objectstore/store_test.cc
index 5ab011ad17d8..4cada7e2e435 100644
--- a/src/test/objectstore/store_test.cc
+++ b/src/test/objectstore/store_test.cc
@@ -279,6 +279,7 @@ TEST_P(StoreTest, FiemapHoles) {
     ASSERT_EQ(r, 0);
   }
   {
+    //fiemap test from 0 to SKIP_STEP * (MAX_EXTENTS - 1) + 3
     bufferlist bl;
     store->fiemap(cid, oid, 0, SKIP_STEP * (MAX_EXTENTS - 1) + 3, bl);
     map<uint64_t,uint64_t> m, e;
@@ -295,6 +296,26 @@ TEST_P(StoreTest, FiemapHoles) {
     ASSERT_TRUE((m.size() == 1 &&
 		 m[0] > SKIP_STEP * (MAX_EXTENTS - 1)) ||
 		 (m.size() == MAX_EXTENTS && extents_exist));
+
+    // fiemap test from SKIP_STEP to SKIP_STEP * (MAX_EXTENTS - 2) + 3
+    // reset bufferlist and map
+    bl.clear();
+    m.clear();
+    e.clear();
+    store->fiemap(cid, oid, SKIP_STEP, SKIP_STEP * (MAX_EXTENTS - 2) + 3, bl);
+    p = bl.begin();
+    ::decode(m, p);
+    cout << " got " << m << std::endl;
+    ASSERT_TRUE(!m.empty());
+    ASSERT_GE(m[SKIP_STEP], 3u);
+    extents_exist = true;
+    if (m.size() == (MAX_EXTENTS - 2)) {
+      for (uint64_t i = 1; i < MAX_EXTENTS - 1; i++)
+	extents_exist = extents_exist && m.count(SKIP_STEP*i);
+    }
+    ASSERT_TRUE((m.size() == 1 &&
+		 m[SKIP_STEP] > SKIP_STEP * (MAX_EXTENTS - 2)) ||
+		 (m.size() == (MAX_EXTENTS - 1) && extents_exist));
   }
   {
     ObjectStore::Transaction t;