Merge tag 'fscache-fixes-20141013' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull fs-cache fixes from David Howells:
 "Two fixes for bugs in CacheFiles and a cleanup in FS-Cache"

* tag 'fscache-fixes-20141013' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  fs/fscache/object-list.c: use __seq_open_private()
  CacheFiles: Fix incorrect test for in-memory object collision
  CacheFiles: Handle object being killed before being set up

3 files changed, 23 insertions, 28 deletions

diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 584743d456c..1c7293c3a93 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -268,20 +268,27 @@ static void cachefiles_drop_object(struct fscache_object *_object)
 	ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
 #endif
 
-	/* delete retired objects */
-	if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) &&
-	    _object != cache->cache.fsdef
-	    ) {
-		_debug("- retire object OBJ%x", object->fscache.debug_id);
-		cachefiles_begin_secure(cache, &saved_cred);
-		cachefiles_delete_object(cache, object);
-		cachefiles_end_secure(cache, saved_cred);
-	}
+	/* We need to tidy the object up if we did in fact manage to open it.
+	 * It's possible for us to get here before the object is fully
+	 * initialised if the parent goes away or the object gets retired
+	 * before we set it up.
+	 */
+	if (object->dentry) {
+		/* delete retired objects */
+		if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) &&
+		    _object != cache->cache.fsdef
+		    ) {
+			_debug("- retire object OBJ%x", object->fscache.debug_id);
+			cachefiles_begin_secure(cache, &saved_cred);
+			cachefiles_delete_object(cache, object);
+			cachefiles_end_secure(cache, saved_cred);
+		}
 
-	/* close the filesystem stuff attached to the object */
-	if (object->backer != object->dentry)
-		dput(object->backer);
-	object->backer = NULL;
+		/* close the filesystem stuff attached to the object */
+		if (object->backer != object->dentry)
+			dput(object->backer);
+		object->backer = NULL;
+	}
 
 	/* note that the object is now inactive */
 	if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index dad7d9542a2..e12f189d539 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -189,7 +189,7 @@ try_again:
 	/* an old object from a previous incarnation is hogging the slot - we
 	 * need to wait for it to be destroyed */
 wait_for_old_object:
-	if (fscache_object_is_live(&object->fscache)) {
+	if (fscache_object_is_live(&xobject->fscache)) {
 		pr_err("\n");
 		pr_err("Error: Unexpected object collision\n");
 		cachefiles_printk_object(object, xobject);
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index b8179ca6bf9..51dde817e1f 100644
--- a/fs/fscache/object-list.c
+++ b/fs/fscache/object-list.c
@@ -380,26 +380,14 @@ no_config:
 static int fscache_objlist_open(struct inode *inode, struct file *file)
 {
 	struct fscache_objlist_data *data;
-	struct seq_file *m;
-	int ret;
 
-	ret = seq_open(file, &fscache_objlist_ops);
-	if (ret < 0)
-		return ret;
-
-	m = file->private_data;
-
-	/* buffer for key extraction */
-	data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL);
-	if (!data) {
-		seq_release(inode, file);
+	data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
+	if (!data)
 		return -ENOMEM;
-	}
 
 	/* get the configuration key */
 	fscache_objlist_config(data);
 
-	m->private = data;
 	return 0;
 }