Added clearer error message for failure to create db directory in DBImpl::Recover()

Summary:
Changed CreateDir() to CreateDirIfMissing() so a directory that already exists now causes and error.

Fixed CreateDirIfMissing() and added Env.DirExists()

Test Plan:
make check to test for regessions

Ran the following to test if the error message is not about lock files not existing
./db_bench --db=dir/testdb

After creating a file "testdb", ran the following to see if it failed with sane error message:
./db_bench --db=testdb

Reviewers: dhruba, emayanke, vamsi, sheki

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D7707

1 files changed, 3 insertions, 3 deletions

diff --git a/hdfs/env_hdfs.h b/hdfs/env_hdfs.h
index 29855a351..2f37dd365 100644
--- a/hdfs/env_hdfs.h
+++ b/hdfs/env_hdfs.h
@@ -162,7 +162,7 @@ class HdfsEnv : public Env {
                         // posix threads, etc.
 
   /**
-   * If the URI is specified of the form hdfs://server:port/path, 
+   * If the URI is specified of the form hdfs://server:port/path,
    * then connect to the specified cluster
    * else connect to default.
    */
@@ -189,7 +189,7 @@ class HdfsEnv : public Env {
     int rem = remaining.find(pathsep);
     std::string portStr = (rem == 0 ? remaining :
                            remaining.substr(0, rem));
-    
+
     tPort port;
     port = atoi(portStr.c_str());
     if (port == 0) {
@@ -199,7 +199,7 @@ class HdfsEnv : public Env {
     return fs;
   }
 
-  void split(const std::string &s, char delim, 
+  void split(const std::string &s, char delim,
              std::vector<std::string> &elems) {
     elems.clear();
     size_t prev = 0;