gfs2: Move variable assignment behind a null pointer check in inode_go_dump

Since commit 27a2660 ("gfs2: Dump nrpages for inodes and their
glocks"), inode_go_dump() computes the address of inode within ip before
checking if ip is NULL.  This isn't a bug by itself, but it can give
rise to bugs later.  Avoid that by checking if ip is NULL first.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Author: elfring

fs/gfs2/glops.c

@@ -535,12 +535,13 @@ static void inode_go_dump(struct seq_file *seq, struct gfs2_glock *gl,
 			  const char *fs_id_buf)
 {
 	struct gfs2_inode *ip = gl->gl_object;
-	struct inode *inode = &ip->i_inode;
+	struct inode *inode;
 	unsigned long nrpages;
 
 	if (ip == NULL)
 		return;
 
+	inode = &ip->i_inode;
 	xa_lock_irq(&inode->i_data.i_pages);
 	nrpages = inode->i_data.nrpages;
 	xa_unlock_irq(&inode->i_data.i_pages);