NTFS: Fix serious data corruption issue when writing.

      Many thanks to Alberto Patino for testing and reporting the data
      corruption.  And many apologies for corrupting his partition.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

fs/ntfs/file.c

@@ -787,6 +787,7 @@ static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
 				vcn_len = rl[1].vcn - vcn;
 				lcn_block = lcn << (vol->cluster_size_bits -
 						blocksize_bits);
+				cdelta = 0;
 				/*
 				 * If the number of remaining clusters in the
 				 * @pages is smaller or equal to the number of