The fact that we used a Vector meant that even if creating a Mount
object succeeded, we were still at a risk that appending to the actual
mounts Vector could fail due to OOM condition. To guard against this,
the mount table is now an IntrusiveList, which always means that when
allocation of a Mount object succeeded, then inserting that object to
the list will succeed, which allows us to fail early in case of OOM
condition.
By protecting all the RefPtr<Custody> objects that may be accessed from
multiple threads at the same time (with spinlocks), we remove the need
for using LockRefPtr<Custody> (which is basically a RefPtr with a
built-in spinlock.)
Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:
- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable
This patch renames the Kernel classes so that they can coexist with
the original AK classes:
- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable
The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.
We often get queried for the root inode, and it will always be cached
in memory anyway, so let's make Ext2FS::root_inode() fast by keeping
the root inode in a dedicated member variable.
