ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /media/db2/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking

#  /var/lib/mysql/ r,
#  /var/lib/mysql/** rwk,
  /media/db2/mysql/ r,
  /media/db2/mysql/** rwk,

sudo service mysql restart

mysql -u root -p

130125 12:35:41  InnoDB: Waiting for the background threads to start
130125 12:35:42 InnoDB: 1.1.8 started; log sequence number 1595675
130125 12:35:42 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306
130125 12:35:42 [Note]   - '127.0.0.1' resolves to '127.0.0.1';
130125 12:35:42 [Note] Server socket created on IP: '127.0.0.1'.
130125 12:35:42 [ERROR] /usr/sbin/mysqld: Can't find file: './mysql/host.frm' (errno: 13)
130125 12:35:42 [ERROR] Fatal error: Can't open and lock privilege tables: Can't find         file: './mysql/host.frm' (errno: 13)
130125 12:35:43 [Note] Plugin 'FEDERATED' is disabled.
/usr/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
130125 12:35:43 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade     to create it.
130125 12:35:43 InnoDB: The InnoDB memory heap is disabled
130125 12:35:43 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130125 12:35:43 InnoDB: Compressed tables use zlib 1.2.7
130125 12:35:43 InnoDB: Using Linux native AIO
130125 12:35:43 InnoDB: Initializing buffer pool, size = 128.0M
130125 12:35:43 InnoDB: Completed initialization of buffer pool
130125 12:35:43 InnoDB: highest supported file format is Barracuda.
InnoDB: Log scan progressed past the checkpoint lsn 49439
130125 12:35:43  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
InnoDB: Doing recovery: scanned up to log sequence number 1595675
130125 12:35:45  InnoDB: Starting an apply batch of log records to the database...
InnoDB: Progress in percents: 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65     66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
InnoDB: Apply batch completed

$ ls /media/db2/mysql -al
total 28732
drwxrwxrwx 3 mysql root      4096 Jan 25 12:39 .
drwxr-xr-x 4 root  root      4096 Jan 25  2013 ..
-rw-rw---- 1 mysql mysql 18874368 Jan 25  2013 ibdata1
-rw-rw---- 1 mysql mysql  5242880 Jan 25 12:39 ib_logfile0
-rw-rw---- 1 mysql mysql  5242880 Jan 25  2013 ib_logfile1
drwx------ 2 root  root      4096 Jan 25  2013 mysql

sudo chown mysql:mysql /mysql/data/dir