CacheFiles: Don't try to dump the index key if the cookie has been cleared

Don't try to dump the index key that distinguishes an object if netfs
data in the cookie the object refers to has been cleared (ie.  the
cookie has passed most of the way through
__fscache_relinquish_cookie()).

Since the netfs holds the index key, we can't get at it once the ->def
and ->netfs_data pointers have been cleared - and a NULL pointer
exception will ensue, usually just after a:

	CacheFiles: Error: Unexpected object collision

error is reported.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 25badd1aec5c677215f20d9bd970261deab2dd35..f4a08d7fa2f70a58a8513110988cc4928a674bdb 100644 (file)
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -56,7 +56,7 @@ void __cachefiles_printk_object(struct cachefiles_object *object,
                       object->fscache.cookie->parent,
                       object->fscache.cookie->netfs_data,
                       object->fscache.cookie->flags);
-               if (keybuf)
+               if (keybuf && cookie->def)
                        keylen = cookie->def->get_key(cookie->netfs_data, keybuf,
                                                      CACHEFILES_KEYBUF_SIZE);
                else