ocfs2: Fixup orphan scan cleanup after failed mount

If the mount fails for any reason, ocfs2_dismount_volume calls
ocfs2_orphan_scan_stop. It requires that ocfs2_orphan_scan_init
be called to setup the mutex and work queues, but that doesn't
happen if the mount has failed and we oops accessing an uninitialized
work queue.

This patch splits the init and startup of the orphan scan, eliminating
the oops.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

fs/ocfs2/journal.c

@@ -1954,10 +1954,16 @@ void ocfs2_orphan_scan_init(struct ocfs2_super *osb)
 	os->os_osb = osb;
 	os->os_count = 0;
 	os->os_seqno = 0;
-	os->os_scantime = CURRENT_TIME;
 	mutex_init(&os->os_lock);
 	INIT_DELAYED_WORK(&os->os_orphan_scan_work, ocfs2_orphan_scan_work);
+}
 
+void ocfs2_orphan_scan_start(struct ocfs2_super *osb)
+{
+	struct ocfs2_orphan_scan *os;
+
+	os = &osb->osb_orphan_scan;
+	os->os_scantime = CURRENT_TIME;
 	if (ocfs2_is_hard_readonly(osb) || ocfs2_mount_local(osb))
 		atomic_set(&os->os_state, ORPHAN_SCAN_INACTIVE);
 	else {

fs/ocfs2/journal.h

@@ -145,6 +145,7 @@ static inline void ocfs2_inode_set_new(struct ocfs2_super *osb,
 
 /* Exported only for the journal struct init code in super.c. Do not call. */
 void ocfs2_orphan_scan_init(struct ocfs2_super *osb);
+void ocfs2_orphan_scan_start(struct ocfs2_super *osb);
 void ocfs2_orphan_scan_stop(struct ocfs2_super *osb);
 void ocfs2_orphan_scan_exit(struct ocfs2_super *osb);
 

fs/ocfs2/super.c

@@ -1182,7 +1182,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	wake_up(&osb->osb_mount_event);
 
 	/* Start this when the mount is almost sure of being successful */
-	ocfs2_orphan_scan_init(osb);
+	ocfs2_orphan_scan_start(osb);
 
 	mlog_exit(status);
 	return status;
@@ -1981,6 +1981,8 @@ static int ocfs2_initialize_super(struct super_block *sb,
 	snprintf(osb->dev_str, sizeof(osb->dev_str), "%u,%u",
 		 MAJOR(osb->sb->s_dev), MINOR(osb->sb->s_dev));
 
+	ocfs2_orphan_scan_init(osb);
+
 	status = ocfs2_recovery_init(osb);
 	if (status) {
 		mlog(ML_ERROR, "Unable to initialize recovery state\n");