packed_ref_cache: increment refcount when locked

Increment the packed_ref_cache reference count while it is locked to
prevent its being freed.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index f33d224..a5a5b5d 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -820,7 +820,9 @@ struct packed_ref_cache {
        /*
         * Iff the packed-refs file associated with this instance is
         * currently locked for writing, this points at the associated
-        * lock (which is owned by somebody else).
+        * lock (which is owned by somebody else).  The referrer count
+        * is also incremented when the file is locked and decremented
+        * when it is unlocked.
         */
        struct lock_file *lock;
 };
@@ -2099,6 +2101,8 @@ int lock_packed_refs(int flags)
        /* Read the current packed-refs while holding the lock: */
        packed_ref_cache = get_packed_ref_cache(&ref_cache);
        packed_ref_cache->lock = &packlock;
+       /* Increment the reference count to prevent it from being freed: */
+       acquire_packed_ref_cache(packed_ref_cache);
        return 0;
 }
 
@@ -2119,6 +2123,7 @@ int commit_packed_refs(void)
        if (commit_lock_file(packed_ref_cache->lock))
                error = -1;
        packed_ref_cache->lock = NULL;
+       release_packed_ref_cache(packed_ref_cache);
        return error;
 }
 
@@ -2131,6 +2136,7 @@ void rollback_packed_refs(void)
                die("internal error: packed-refs not locked");
        rollback_lock_file(packed_ref_cache->lock);
        packed_ref_cache->lock = NULL;
+       release_packed_ref_cache(packed_ref_cache);
        clear_packed_ref_cache(&ref_cache);
 }