src/patches/suse-2.6.27.25/patches.suse/osync-error

   1 From: mason@suse.de
   2 Subject: make sure O_SYNC writes properly return -EIO
   3 References: bnc#58622
   4
   5 Make sure to honor the error status of synchronous writeback during
   6 O_SYNC writes
   7
   8 Acked-by: Jeff Mahoney <jeffm@suse.com>
   9
  10 ---
  11  mm/filemap.c |   17 +++++++++++++++--
  12  1 file changed, 15 insertions(+), 2 deletions(-)
  13
  14 --- a/mm/filemap.c
  15 +++ b/mm/filemap.c
  16 @@ -2497,7 +2497,7 @@ generic_file_buffered_write(struct kiocb
  17
  18         if (likely(status >= 0)) {
  19                 written += status;
  20 -               *ppos = pos + status;
  21 +               pos += status;
  22
  23                 /*
  24                  * For now, when the user asks for O_SYNC, we'll actually give
  25 @@ -2515,10 +2515,23 @@ generic_file_buffered_write(struct kiocb
  26          * to buffered writes (block instantiation inside i_size).  So we sync
  27          * the file data here, to try to honour O_DIRECT expectations.
  28          */
  29 -       if (unlikely(file->f_flags & O_DIRECT) && written)
  30 +       if (unlikely(file->f_flags & O_DIRECT) && status >= 0 && written)
  31                 status = filemap_write_and_wait_range(mapping,
  32                                         pos, pos + written - 1);
  33
  34 +       /*
  35 +        * We must let know userspace if something hasn't been written
  36 +        * correctly. If we got an I/O error it means we got an hardware
  37 +        * failure, anything can be happening to the on-disk data,
  38 +        * letting know userspace that a bit of data might have been
  39 +        * written correctly on disk is a very low priority, compared
  40 +        * to letting know userspace that some data has _not_ been
  41 +        * written at all.
  42 +        */
  43 +       if (unlikely(status == -EIO))
  44 +               return status;
  45 +       *ppos = pos;
  46 +
  47         return written ? written : status;
  48  }
  49  EXPORT_SYMBOL(generic_file_buffered_write);