ocfs2: ocfs2_write_begin_nolock() should handle len=0
commit 8379e7c46cc48f51197dd663fc6676f47f2a1e71 upstream.
Bug introduced by mainline commit e7432675f8ca868a4af365759a8d4c3779a3d922
The bug causes ocfs2_write_begin_nolock() to oops when len=0.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 50bb561..0f04b70 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1748,8 +1748,8 @@
* we know zeros will only be needed in the first and/or last cluster.
*/
if (clusters_to_alloc || extents_to_split ||
- wc->w_desc[0].c_needs_zero ||
- wc->w_desc[wc->w_clen - 1].c_needs_zero)
+ (wc->w_clen && (wc->w_desc[0].c_needs_zero ||
+ wc->w_desc[wc->w_clen - 1].c_needs_zero)))
cluster_of_pages = 1;
else
cluster_of_pages = 0;
