ocfs2: Use buffer IO if we are appending a file.

In ocfs2_file_aio_write, we will prevent direct io if
we find that we are appending(changing i_size) and call
generic_file_aio_write_nolock. But actually O_DIRECT flag
is there and this function will call generic_file_direct_write
eventually which will update i_size and leave di->i_size
alone. The bug is
http://oss.oracle.com/bugzilla/show_bug.cgi?id=1173.

So this patch let ocfs2_direct_IO returns 0 directly if we
are appending so that buffered write will be called and
di->i_size get updated successfully. And this is also
what we want in ocfs2_file_aio_write.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 33e03c551127..72e76062a900 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -690,6 +690,10 @@ static ssize_t ocfs2_direct_IO(int rw,
         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
                 return 0;
 
+        /* Fallback to buffered I/O if we are appending. */
+        if (i_size_read(inode) <= offset)
+                return 0;
+
         ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
                                             inode->i_sb->s_bdev, iov, offset,
                                             nr_segs,