[Cluster-devel] GFS2: Fix cache coherency between truncate and O_DIRECT read

[Steven Whitehouse]

If a page was partially zeroed as the result of a truncate, then it was
not being correctly marked dirty. This resulted in the deleted data
reappearing if the file was read back via direct I/O.

Reported-by: Eric Sandeen <sandeen at redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho at redhat.com>


diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 1153a07..3297635 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1012,7 +1012,7 @@ static int gfs2_block_truncate_page(struct address_space *mapping)
 		gfs2_trans_add_bh(ip->i_gl, bh, 0);
 
 	zero_user(page, offset, length);
-
+	mark_buffer_dirty(bh);
 unlock:
 	unlock_page(page);
 	page_cache_release(page);