GFS2: check NULL return value in gfs2_ok_to_move

gfs2_lookupi() can return NULL if the path to the root is broken by
another rename/rmdir. In this case gfs2_ok_to_move() must check for
this NULL pointer and return error.

Resolves: rhbz#1060246
Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index ec455b92091f..b52ebf8553c2 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1299,6 +1299,10 @@ static int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to)
                 }
 
                 tmp = gfs2_lookupi(dir, &gfs2_qdotdot, 1);
+                if (!tmp) {
+                        error = -ENOENT;
+                        break;
+                }
                 if (IS_ERR(tmp)) {
                         error = PTR_ERR(tmp);
                         break;