From 84ca553659375b549c105276c612ce9be4517bfd Mon Sep 17 00:00:00 2001 From: Jeff King Date: Fri, 8 Dec 2017 06:22:22 -0500 Subject: refs: drop "clear packed-refs while locked" assertion In clear_packed_ref_cache(), we assert that we're not currently holding the packed-refs lock. But in each of the three code paths that can hit this, the assertion is either a noop or actively does the wrong thing: 1. in rollback_packed_refs(), we will have just released the lock before calling the function, and so the assertion can never trigger. 2. get_packed_ref_cache() can reach this assertion via validate_packed_ref_cache(). But it calls the validate function only when it knows that we're not holding the lock, so again, the assertion can never trigger. 3. lock_packed_refs() also calls validate_packed_ref_cache(). In this case we're _always_ holding the lock, which means any time the validate function has to clear the cache, we'll trigger this assertion and die. This doesn't happen often in practice because the validate function clears the cache only if we find that somebody else has racily rewritten the packed-refs file between the time we read it and the time we took the lock. So most of the time we don't reach the assertion at all (nobody has racily written the file so there's no need to clear the cache). And when we do, it is not actually indicative of a bug; clearing the cache while holding the lock is the right thing to do here. This final case is relatively new, being triggerd by the extra validation added in fed6ebebf1 (lock_packed_refs(): fix cache validity check, 2017-06-12). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- refs/files-backend.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/refs/files-backend.c b/refs/files-backend.c index f21a954ce7..dd41e1d382 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -99,8 +99,6 @@ static void clear_packed_ref_cache(struct files_ref_store *refs) if (refs->packed) { struct packed_ref_cache *packed_refs = refs->packed; - if (is_lock_file_locked(&refs->packed_refs_lock)) - die("BUG: packed-ref cache cleared while locked"); refs->packed = NULL; release_packed_ref_cache(packed_refs); } -- cgit v1.2.1