From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 07 Apr 2014 16:37:19 GMT
Subject: Re: [PATCH 04/22] rollback_lock_file(): set fd to -1
Message-ID: <xmqqfvlpnlj4.fsf@gitster.dls.corp.google.com>
In-Reply-To: <5341CAE2.8040600@alum.mit.edu>

Michael Haggerty <mhagger@alum.mit.edu> writes:

> The first use of a lock_file object necessarily passes through
> lock_file().  The only precondition for that function is that the
> on_list field is zero, which is satisfied by a xcalloc()ed object.
>
> Subsequent uses of a lock_file object must *not* zero the object.
> lock_file objects are added to the lock_file_list and never removed.  So
> zeroing a lock_file object would discard the rest of the linked list.
> But subsequent uses must also pass through lock_file(), which sees that
> on_list is set, and assumes that the object is in a self-consistent
> state as left by commit_lock_file() or rollback_lock_file().
>
> At least that's how it is supposed to work.  But lock_file objects are
> in fact not cleaned up correctly in all circumstances.  The next version
> of this patch series will work to fix that.

Thanks; I see the next round already posted to the list.