xfs: remove nr_to_write writeback windup.

Now that the background flush code has been fixed, we shouldn't need to
silently multiply the wbc->nr_to_write to get good writeback. Remove
that code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/xfs/linux-2.6/xfs_aops.c

@@ -1381,14 +1381,6 @@ xfs_vm_writepage(
 	if (!page_has_buffers(page))
 		create_empty_buffers(page, 1 << inode->i_blkbits, 0);
 
-
-	/*
-	 *  VM calculation for nr_to_write seems off.  Bump it way
-	 *  up, this gets simple streaming writes zippy again.
-	 *  To be reviewed again after Jens' writeback changes.
-	 */
-	wbc->nr_to_write *= 4;
-
 	/*
 	 * Convert delayed allocate, unwritten or unmapped space
 	 * to real space and flush out to disk.