# name       : sql_no_fcache.patch
# introduced : 12
# maintainer : Oleg
#
#!!! notice !!!
# Any small change to this file in the main branch
# should be done or reviewed by the maintainer!
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -143,6 +143,8 @@
 static uint opt_protocol= 0;
 static char *opt_plugin_dir= 0, *opt_default_auth= 0;
 
+static my_bool server_supports_sql_no_fcache= FALSE;
+
 /*
 Dynamic_string wrapper functions. In this file use these
 wrappers, they will terminate the process if there is
@@ -1496,6 +1498,17 @@
     /* Don't switch charsets for 4.1 and earlier.  (bug#34192). */
     server_supports_switching_charsets= FALSE;
   } 
+  
+  /* Check to see if we support SQL_NO_FCACHE on this server. */ 
+  if (mysql_query(mysql, "SELECT SQL_NO_FCACHE NOW()") == 0)
+  {
+    MYSQL_RES *res = mysql_store_result(mysql);
+    if (res)
+    {
+      mysql_free_result(res);
+    }
+    server_supports_sql_no_fcache= TRUE;
+  }
   /*
     As we're going to set SQL_MODE, it would be lost on reconnect, so we
     cannot reconnect.
@@ -3177,7 +3190,12 @@
 
     /* now build the query string */
 
-    dynstr_append_checked(&query_string, "SELECT /*!40001 SQL_NO_CACHE */ * INTO OUTFILE '");
+    dynstr_append_checked(&query_string, "SELECT /*!40001 SQL_NO_CACHE */ ");
+    if (server_supports_sql_no_fcache)
+    {
+      dynstr_append_checked(&query_string, "/*!50084 SQL_NO_FCACHE */ ");
+    }
+    dynstr_append_checked(&query_string, "* INTO OUTFILE '");
     dynstr_append_checked(&query_string, filename);
     dynstr_append_checked(&query_string, "'");
 
@@ -3227,7 +3245,12 @@
       check_io(md_result_file);
     }
     
-    dynstr_append_checked(&query_string, "SELECT /*!40001 SQL_NO_CACHE */ * FROM ");
+    dynstr_append_checked(&query_string, "SELECT /*!40001 SQL_NO_CACHE */ ");
+    if (server_supports_sql_no_fcache)
+    {
+      dynstr_append_checked(&query_string, "/*!50084 SQL_NO_FCACHE */ ");
+    }
+    dynstr_append_checked(&query_string, "* FROM ");
     dynstr_append_checked(&query_string, result_table);
 
     if (where)
--- /dev/null
+++ b/include/flashcache_ioctl.h
@@ -0,0 +1,53 @@
+/****************************************************************************
+ *  flashcache_ioctl.h
+ *  FlashCache: Device mapper target for block-level disk caching
+ *
+ *  Copyright 2010 Facebook, Inc.
+ *  Author: Mohan Srinivasan (mohan@facebook.com)
+ *
+ *  Based on DM-Cache:
+ *   Copyright (C) International Business Machines Corp., 2006
+ *   Author: Ming Zhao (mingzhao@ufl.edu)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ ****************************************************************************/
+
+#ifndef FLASHCACHE_IOCTL_H
+#define FLASHCACHE_IOCTL_H
+
+#include <linux/types.h>
+
+#define FLASHCACHE_IOCTL 0xfe
+
+enum {
+       FLASHCACHEADDNCPID_CMD=200,
+       FLASHCACHEDELNCPID_CMD,
+       FLASHCACHEDELNCALL_CMD,
+       FLASHCACHEADDWHITELIST_CMD,
+       FLASHCACHEDELWHITELIST_CMD,
+       FLASHCACHEDELWHITELISTALL_CMD,
+};
+
+#define FLASHCACHEADDNCPID     _IOW(FLASHCACHE_IOCTL, FLASHCACHEADDNCPID_CMD, pid_t)
+#define FLASHCACHEDELNCPID     _IOW(FLASHCACHE_IOCTL, FLASHCACHEDELNCPID_CMD, pid_t)
+#define FLASHCACHEDELNCALL     _IOW(FLASHCACHE_IOCTL, FLASHCACHEDELNCALL_CMD, pid_t)
+
+#define FLASHCACHEADDBLACKLIST         FLASHCACHEADDNCPID
+#define FLASHCACHEDELBLACKLIST         FLASHCACHEDELNCPID
+#define FLASHCACHEDELALLBLACKLIST      FLASHCACHEDELNCALL
+
+#define FLASHCACHEADDWHITELIST         _IOW(FLASHCACHE_IOCTL, FLASHCACHEADDWHITELIST_CMD, pid_t)
+#define FLASHCACHEDELWHITELIST         _IOW(FLASHCACHE_IOCTL, FLASHCACHEDELWHITELIST_CMD, pid_t)
+#define FLASHCACHEDELALLWHITELIST      _IOW(FLASHCACHE_IOCTL, FLASHCACHEDELWHITELISTALL_CMD, pid_t)
+
+#endif
--- /dev/null
+++ b/patch_info/sql_no_fcache.info
@@ -0,0 +1,6 @@
+File=sql_no_fcache.patch
+Name=Support for flashcache including the SQL_NO_FCACHE option that prevents blocks from being cached during a query.
+Version=1.0
+Author=Facebook
+License=GPL
+Comment=
--- a/sql/lex.h
+++ b/sql/lex.h
@@ -516,6 +516,7 @@
   { "SQL_CACHE",        SYM(SQL_CACHE_SYM)},
   { "SQL_CALC_FOUND_ROWS", SYM(SQL_CALC_FOUND_ROWS)},
   { "SQL_NO_CACHE",	SYM(SQL_NO_CACHE_SYM)},
+  { "SQL_NO_FCACHE",   SYM(SQL_NO_FCACHE_SYM)},
   { "SQL_SMALL_RESULT", SYM(SQL_SMALL_RESULT)},
   { "SQL_THREAD",	SYM(SQL_THREAD)},
   { "SQL_TSI_SECOND",   SYM(SECOND_SYM)},
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -195,6 +195,8 @@
 extern char language[FN_REFLEN];
 extern "C" MYSQL_PLUGIN_IMPORT ulong server_id;
 extern ulong concurrency;
+/* flashcache */
+extern int cachedev_fd;
 extern time_t server_start_time, flush_status_time;
 extern char *opt_mysql_tmpdir, mysql_charsets_dir[];
 extern int mysql_unpacked_real_data_home_len;
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -86,6 +86,11 @@
 #ifdef HAVE_SYS_PRCTL_H
 #include <sys/prctl.h>
 #endif
+#if defined(__linux__)
+#include <mntent.h>
+#include <sys/statfs.h>
+#include "flashcache_ioctl.h"
+#endif//__linux__
 
 #include <thr_alarm.h>
 #include <ft_global.h>
@@ -491,6 +496,11 @@
 ulong binlog_cache_use= 0, binlog_cache_disk_use= 0;
 ulong binlog_stmt_cache_use= 0, binlog_stmt_cache_disk_use= 0;
 ulong max_connections, max_connect_errors;
+
+/* flashcache */
+int cachedev_fd;
+my_bool cachedev_enabled= FALSE;
+
 /*
   Maximum length of parameter value which can be set through
   mysql_send_long_data() call.
@@ -4102,6 +4112,97 @@
 #define decrement_handler_count()
 #endif /* defined(_WIN32) || defined(HAVE_SMEM) */
 
+#if defined(__linux__)
+/*
+ * Auto detect if we support flash cache on the host system.
+ * This needs to be called before we setuid away from root
+ * to avoid permission problems on opening the device node.
+ */
+static void init_cachedev(void)
+{
+  struct statfs stfs_data_home_dir;
+  struct statfs stfs;
+  struct mntent *ent;
+  pid_t pid = getpid();
+  FILE *mounts;
+  const char *error_message= NULL;
+
+  // disabled by default
+  cachedev_fd = -1;
+  cachedev_enabled= FALSE;
+
+  if (!mysql_data_home)
+  {
+    error_message= "mysql_data_home not set";
+    goto epilogue;
+  }
+
+  if (statfs(mysql_data_home, &stfs_data_home_dir) < 0)
+  {
+    error_message= "statfs failed";
+    goto epilogue;
+  }
+
+  mounts = setmntent("/etc/mtab", "r");
+  if (mounts == NULL)
+  {
+    error_message= "setmntent failed";
+    goto epilogue;
+  }
+
+  while ((ent = getmntent(mounts)) != NULL)
+  {
+    if (statfs(ent->mnt_dir, &stfs) < 0)
+      continue;
+    if (memcmp(&stfs.f_fsid, &stfs_data_home_dir.f_fsid, sizeof(fsid_t)) == 0)
+      break;
+  }
+  endmntent(mounts);
+
+  if (ent == NULL)
+  {
+    error_message= "getmntent loop failed";
+    goto epilogue;
+  }
+
+  cachedev_fd = open(ent->mnt_fsname, O_RDONLY);
+  if (cachedev_fd < 0)
+  {
+    error_message= "open flash device failed";
+    goto epilogue;
+  }
+
+  /* cleanup previous whitelistings */
+  if (ioctl(cachedev_fd, FLASHCACHEDELALLWHITELIST, &pid) < 0)
+  {
+    close(cachedev_fd);
+    cachedev_fd = -1;
+    error_message= "ioctl failed";
+  } else {
+    ioctl(cachedev_fd, FLASHCACHEADDWHITELIST, &pid);
+  }
+
+epilogue:
+  sql_print_information("Flashcache bypass: %s",
+      (cachedev_fd > 0) ? "enabled" : "disabled");
+  if (error_message)
+    sql_print_information("Flashcache setup error is : %s\n", error_message);
+  else
+    cachedev_enabled= TRUE;
+
+}
+
+static void cleanup_cachedev(void)
+{
+  pid_t pid = getpid();
+
+  if (cachedev_enabled) {
+    ioctl(cachedev_fd, FLASHCACHEDELWHITELIST, &pid);
+    close(cachedev_fd);
+    cachedev_fd = -1;
+  }
+}
+#endif//__linux__
 
 #ifndef EMBEDDED_LIBRARY
 #ifndef DBUG_OFF
@@ -4363,6 +4464,10 @@
   test_lc_time_sz();
 #endif
 
+#if defined(__linux__)
+  init_cachedev();
+#endif//__linux__
+
   /*
     We have enough space for fiddling with the argv, continue
   */
@@ -4574,6 +4679,10 @@
   }
 #endif
   clean_up(1);
+#if defined(__linux__)
+  cleanup_cachedev();
+#endif//__linux__
+
   mysqld_exit(0);
 }
 
@@ -6421,6 +6530,7 @@
   {"Delayed_errors",           (char*) &delayed_insert_errors,  SHOW_LONG},
   {"Delayed_insert_threads",   (char*) &delayed_insert_threads, SHOW_LONG_NOFLUSH},
   {"Delayed_writes",           (char*) &delayed_insert_writes,  SHOW_LONG},
+  {"Flashcache_enabled",       (char*) &cachedev_enabled,       SHOW_BOOL },
   {"Flush_commands",           (char*) &refresh_version,        SHOW_LONG_NOFLUSH},
   {"Handler_commit",           (char*) offsetof(STATUS_VAR, ha_commit_count), SHOW_LONG_STATUS},
   {"Handler_delete",           (char*) offsetof(STATUS_VAR, ha_delete_count), SHOW_LONG_STATUS},
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -390,6 +390,7 @@
   lex->describe= 0;
   lex->subqueries= FALSE;
   lex->context_analysis_only= 0;
+  lex->disable_flashcache= FALSE;
   lex->derived_tables= 0;
   lex->safe_to_cache_query= 1;
   lex->leaf_tables_insert= 0;
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -2346,6 +2346,7 @@
 
   enum enum_yes_no_unknown tx_chain, tx_release;
   bool safe_to_cache_query;
+  bool disable_flashcache;
   bool subqueries, ignore;
   st_parsing_options parsing_options;
   Alter_info alter_info;
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -55,6 +55,12 @@
 
 #define PREV_BITS(type,A)	((type) (((type) 1 << (A)) -1))
 
+#include <sys/syscall.h>
+#include <sys/ioctl.h>
+#if defined(__linux__)
+#include "flashcache_ioctl.h"
+#endif//__linux__
+
 const char *join_type_str[]={ "UNKNOWN","system","const","eq_ref","ref",
 			      "MAYBE_REF","ALL","range","index","fulltext",
 			      "ref_or_null","unique_subquery","index_subquery",
@@ -266,8 +272,17 @@
                    ulong setup_tables_done_option)
 {
   bool res;
+  pid_t pid;
   register SELECT_LEX *select_lex = &lex->select_lex;
   DBUG_ENTER("handle_select");
+#if defined(__linux__)
+  if(lex->disable_flashcache && cachedev_fd > 0)
+  {
+    pid = syscall(SYS_gettid);
+    ioctl(cachedev_fd, FLASHCACHEADDNCPID, &pid);
+  }
+#endif//__linux__
+ 
   MYSQL_SELECT_START(thd->query());
 
   if (select_lex->master_unit()->is_union() || 
@@ -302,6 +317,12 @@
   if (unlikely(res))
     result->abort_result_set();
 
+#if defined(__linux__)
+  if (lex->disable_flashcache && cachedev_fd > 0)
+  {
+    ioctl(cachedev_fd, FLASHCACHEDELNCPID, &pid);
+  }
+#endif//__linux__ 
   MYSQL_SELECT_DONE((int) res, (ulong) thd->limit_found_rows);
   DBUG_RETURN(res);
 }
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -1284,6 +1284,7 @@
 %token  SQL_CACHE_SYM
 %token  SQL_CALC_FOUND_ROWS
 %token  SQL_NO_CACHE_SYM
+%token  SQL_NO_FCACHE_SYM
 %token  SQL_SMALL_RESULT
 %token  SQL_SYM                       /* SQL-2003-R */
 %token  SQL_THREAD
@@ -7362,6 +7363,10 @@
               Lex->select_lex.sql_cache= SELECT_LEX::SQL_NO_CACHE;
             }
           }
+	| SQL_NO_FCACHE_SYM
+	  {
+	    Lex->disable_flashcache= TRUE;
+	  }
         | SQL_CACHE_SYM
           {
             /* 
--- /dev/null
+++ b/mysql-test/r/percona_sql_no_fcache.result
@@ -0,0 +1,12 @@
+drop table if exists t1;
+create table t (a int not null);
+insert into t values (1),(2),(3);
+SELECT SQL_NO_FCACHE SLEEP(0);
+SLEEP(0)
+0
+SELECT /*!40001 SQL_NO_CACHE */ /*!50084 SQL_NO_FCACHE */ * FROM t;
+a
+1
+2
+3
+DROP TABLE t;
--- /dev/null
+++ b/mysql-test/t/percona_sql_no_fcache.test
@@ -0,0 +1,11 @@
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+create table t (a int not null);
+insert into t values (1),(2),(3);
+
+SELECT SQL_NO_FCACHE SLEEP(0);
+SELECT /*!40001 SQL_NO_CACHE */ /*!50084 SQL_NO_FCACHE */ * FROM t;
+
+DROP TABLE t;