nilfs2: fix missing cleanup on rollforward recovery error

In an error injection test of a routine for mount-time recovery, KASAN
found a use-after-free bug.

It turned out that if data recovery was performed using partial logs
created by dsync writes, but an error occurred before starting the log
writer to create a recovered checkpoint, the inodes whose data had been
recovered were left in the ns_dirty_files list of the nilfs object and
were not freed.

Fix this issue by cleaning up inodes that have read the recovery data if
the recovery routine fails midway before the log writer starts.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 0f3e1c7 ("nilfs2: recovery functions")
Signed-off-by: Ryusuke Konishi <[email protected]>
Tested-by: Ryusuke Konishi <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

fs/nilfs2/recovery.c

@@ -715,6 +715,33 @@ static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
 	brelse(bh);
 }
 
+/**
+ * nilfs_abort_roll_forward - cleaning up after a failed rollforward recovery
+ * @nilfs: nilfs object
+ */
+static void nilfs_abort_roll_forward(struct the_nilfs *nilfs)
+{
+	struct nilfs_inode_info *ii, *n;
+	LIST_HEAD(head);
+
+	/* Abandon inodes that have read recovery data */
+	spin_lock(&nilfs->ns_inode_lock);
+	list_splice_init(&nilfs->ns_dirty_files, &head);
+	spin_unlock(&nilfs->ns_inode_lock);
+	if (list_empty(&head))
+		return;
+
+	set_nilfs_purging(nilfs);
+	list_for_each_entry_safe(ii, n, &head, i_dirty) {
+		spin_lock(&nilfs->ns_inode_lock);
+		list_del_init(&ii->i_dirty);
+		spin_unlock(&nilfs->ns_inode_lock);
+
+		iput(&ii->vfs_inode);
+	}
+	clear_nilfs_purging(nilfs);
+}
+
 /**
  * nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint
  * @nilfs: nilfs object
@@ -773,15 +800,19 @@ int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
 		if (unlikely(err)) {
 			nilfs_err(sb, "error %d writing segment for recovery",
 				  err);
-			goto failed;
+			goto put_root;
 		}
 
 		nilfs_finish_roll_forward(nilfs, ri);
 	}
 
- failed:
+put_root:
 	nilfs_put_root(root);
 	return err;
+
+failed:
+	nilfs_abort_roll_forward(nilfs);
+	goto put_root;
 }
 
 /**