diff --git a/util/file_allocator.cpp b/util/file_allocator.cpp
index b0572f9..567de10 100644
--- a/util/file_allocator.cpp
+++ b/util/file_allocator.cpp
@@ -23,6 +23,11 @@
 #include <sys/stat.h>
 #endif
 
+#if defined(__linux__)
+#include <sys/vfs.h>
+#include <linux/magic.h>
+#endif
+
 #include "timer.h"
 #include "mongoutils/str.h"
 using namespace mongoutils;
@@ -142,6 +147,19 @@ namespace mongo {
 
     void FileAllocator::ensureLength(int fd , long size) {
 #if defined(__linux__)
+        {
+            // Detect NFS and use ftruncate rather than fallocate
+            struct statfs fs_stats;
+            int ret = fstatfs(fd, &fs_stats);
+            uassert(15933, "fstatfs failed: " + errnoWithDescription(), ret == 0);
+
+            if (fs_stats.f_type == NFS_SUPER_MAGIC) {
+                ret = ftruncate(fd, size);
+                uassert(15934, "ftruncate failed: " + errnoWithDescription(), ret == 0);
+                return;
+            }
+        }
+
         int ret = posix_fallocate(fd,0,size);
         if ( ret == 0 )
             return;