PageError() when such errors are detected in the async i/o handler           fs/ntfs/aops.c::ntfs_end_buffer_async_read().  All users of mst           protected attributes now check the magic of each ntfs record as they           use it and act appropriately.  This has the effect of making errors
      granular per ntfs record rather than per page which solves the case
      where we cannot access any of the ntfs records in a page when a
      single one of them had an mst error.  (Thanks to Ken MacFerrin for
      the bug report.)
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>