jbd: Revise KERN_EMERG error messages

Some of KERN_EMERG printk messages do not really deserve this log level
and the one in log_wait_commit() is even rather useless (the journal has
been previously aborted and *that* is where we should have been
complaining). So make some messages just KERN_ERR and remove the useless
message.

Signed-off-by: Jan Kara <jack@suse.cz>
udf: Fix lockdep warning from udf_symlink()

Lockdep is complaining about UDF:
=============================================
[ INFO: possible recursive locking detected ]
3.12.0+ #16 Not tainted
---------------------------------------------
ln/7386 is trying to acquire lock:
 (&ei->i_data_sem){+.+...}, at: [<ffffffff8142f06d>] udf_get_block+0x8d/0x130

but task is already holding lock:
 (&ei->i_data_sem){+.+...}, at: [<ffffffff81431a8d>] udf_symlink+0x8d/0x690

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&ei->i_data_sem);
  lock(&ei->i_data_sem);

 *** DEADLOCK ***

This is because we hold i_data_sem of the symlink inode while calling
udf_add_entry() for the directory. I don't think this can ever lead to
deadlocks since we never hold i_data_sem for two inodes in any other
place.

The fix is simple - move unlock of i_data_sem for symlink inode up. We
don't need it for anything when linking symlink inode to directory.

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull UDF & jbd fixes from Jan Kara:
 "A cleanup of JBD log messages and UDF fix of a lockdep warning"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  udf: Fix lockdep warning from udf_symlink()
  jbd: Revise KERN_EMERG error messages