JFFS2: add missing verify buffer allocation/deallocation

The function jffs2_nor_wbuf_flash_setup() doesn't allocate the verify buffer
if CONFIG_JFFS2_FS_WBUF_VERIFY is defined, so causing a kernel panic when
that macro is enabled and the verify function is called. Similarly the
jffs2_nor_wbuf_flash_cleanup() must free the buffer if
CONFIG_JFFS2_FS_WBUF_VERIFY is enabled.
The following patch fixes the problem.
The following patch applies to 2.6.30 kernel.

Signed-off-by: Massimo Cirillo <maxcir@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org

fs/jffs2/wbuf.c

@@ -1268,10 +1268,20 @@ int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c) {
 	if (!c->wbuf)
 		return -ENOMEM;
 
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+	c->wbuf_verify = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+	if (!c->wbuf_verify) {
+		kfree(c->wbuf);
+		return -ENOMEM;
+	}
+#endif
 	return 0;
 }
 
 void jffs2_nor_wbuf_flash_cleanup(struct jffs2_sb_info *c) {
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+	kfree(c->wbuf_verify);
+#endif
 	kfree(c->wbuf);
 }