NTFS: Fix a mount time deadlock.

Big thanks go to Mathias Kolehmainen for reporting the bug, providing
debug output and testing the patches I sent him to get it working.

The fix was to stop calling ntfs_attr_set() at mount time as that causes
balance_dirty_pages_ratelimited() to be called which on systems with
little memory actually tries to go and balance the dirty pages which tries
to take the s_umount semaphore but because we are still in fill_super()
across which the VFS holds s_umount for writing this results in a
deadlock.

We now do the dirty work by hand by submitting individual buffers.  This
has the annoying "feature" that mounting can take a few seconds if the
journal is large as we have clear it all.  One day someone should improve
on this by deferring the journal clearing to a helper kernel thread so it
can be done in the background but I don't have time for this at the moment
and the current solution works fine so I am leaving it like this for now.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ntfs/runlist.c

@@ -1,7 +1,7 @@
 /**
  * runlist.c - NTFS runlist handling code.  Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2005 Anton Altaparmakov
+ * Copyright (c) 2001-2007 Anton Altaparmakov
  * Copyright (c) 2002-2005 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -1714,7 +1714,7 @@ extend_hole:
 					sizeof(*rl));
 		/* Adjust the beginning of the tail if necessary. */
 		if (end > rl->vcn) {
-			s64 delta = end - rl->vcn;
+			delta = end - rl->vcn;
 			rl->vcn = end;
 			rl->length -= delta;
 			/* Only adjust the lcn if it is real. */