From 979f3e239906b2a6b5d648bbed6241f327fd7075 Mon Sep 17 00:00:00 2001
From: Volker Lendecke <vl@samba.org>
Date: Wed, 15 May 2024 17:26:27 +0200
Subject: [PATCH] smbd: Remove the ZERO_ZERO define

This code went in with e8e98c9ea06 in 2001 without any mention in the
commit message.

I don't remember all details, but there was some discussion around the
offset=0,length=0 lock being somehow special. These days [MS-FSA]
defines the required behaviour (don't conflict) and we implement that
behaviour.

If someone still remembers why this code is in and thinks it's
worthwhile, that's what version control is for.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
---
 source3/locking/brlock.c | 88 ----------------------------------------
 1 file changed, 88 deletions(-)

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 328a9bfba3d..b0295174954 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -38,8 +38,6 @@
 #undef DBGC_CLASS
 #define DBGC_CLASS DBGC_LOCKING
 
-#define ZERO_ZERO 0
-
 /* The open brlock.tdb database. */
 
 static struct db_context *brlock_db;
@@ -268,32 +266,6 @@ static bool brl_conflict_posix(const struct lock_struct *lck1,
 	return brl_overlap(lck1, lck2);
 }
 
-#if ZERO_ZERO
-static bool brl_conflict1(const struct lock_struct *lck1,
-			 const struct lock_struct *lck2)
-{
-	if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK) {
-		return False;
-	}
-
-	if (brl_same_context(&lck1->context, &lck2->context) &&
-	    lck2->lock_type == READ_LOCK && lck1->fnum == lck2->fnum) {
-		return False;
-	}
-
-	if (lck2->start == 0 && lck2->size == 0 && lck1->size != 0) {
-		return True;
-	}
-
-	if (lck1->start >= (lck2->start + lck2->size) ||
-	    lck2->start >= (lck1->start + lck1->size)) {
-		return False;
-	}
-
-	return True;
-}
-#endif
-
 /****************************************************************************
  Check to see if this lock conflicts, but ignore our own locks on the
  same fnum only. This is the read/write lock check code path.
@@ -399,21 +371,6 @@ void brl_shutdown(void)
 	TALLOC_FREE(brlock_db);
 }
 
-#if ZERO_ZERO
-/****************************************************************************
- Compare two locks for sorting.
-****************************************************************************/
-
-static int lock_compare(const struct lock_struct *lck1,
-			 const struct lock_struct *lck2)
-{
-	if (lck1->start != lck2->start) {
-		return NUMERIC_CMP(lck1->start, lck2->start);
-	}
-	return NUMERIC_CMP(lck1->size, lck2->size);
-}
-#endif
-
 /****************************************************************************
  Lock a range of bytes - Windows lock semantics.
 ****************************************************************************/
@@ -446,12 +403,6 @@ NTSTATUS brl_lock_windows_default(struct byte_range_lock *br_lck,
 			plock->context.smblctx = locks[i].context.smblctx;
 			return NT_STATUS_LOCK_NOT_GRANTED;
 		}
-#if ZERO_ZERO
-		if (plock->start == 0 && plock->size == 0 &&
-				locks[i].size == 0) {
-			break;
-		}
-#endif
 	}
 
 	contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WINDOWS_BRL);
@@ -983,12 +934,6 @@ NTSTATUS brl_lock(
 
 	ZERO_STRUCT(lock);
 
-#if !ZERO_ZERO
-	if (start == 0 && size == 0) {
-		DEBUG(0,("client sent 0/0 lock - please report this\n"));
-	}
-#endif
-
 	lock = (struct lock_struct) {
 		.context.smblctx = smblctx,
 		.context.pid = pid,
@@ -1007,10 +952,6 @@ NTSTATUS brl_lock(
 		ret = brl_lock_posix(br_lck, &lock);
 	}
 
-#if ZERO_ZERO
-	/* sort the lock list */
-	TYPESAFE_QSORT(br_lck->lock_data, (size_t)br_lck->num_locks, lock_compare);
-#endif
 	/* If we're returning an error, return who blocked us. */
 	if (!NT_STATUS_IS_OK(ret) && psmblctx) {
 		*blocker_pid = lock.context.pid;
@@ -1032,31 +973,6 @@ bool brl_unlock_windows_default(struct byte_range_lock *br_lck,
 
 	SMB_ASSERT(plock->lock_type == UNLOCK_LOCK);
 
-#if ZERO_ZERO
-	/* Delete write locks by preference... The lock list
-	   is sorted in the zero zero case. */
-
-	for (i = 0; i < br_lck->num_locks; i++) {
-		struct lock_struct *lock = &locks[i];
-
-		if (lock->lock_type == WRITE_LOCK &&
-		    brl_same_context(&lock->context, &plock->context) &&
-		    lock->fnum == plock->fnum &&
-		    lock->lock_flav == WINDOWS_LOCK &&
-		    lock->start == plock->start &&
-		    lock->size == plock->size) {
-
-			/* found it - delete it */
-			deleted_lock_type = lock->lock_type;
-			break;
-		}
-	}
-
-	if (i != br_lck->num_locks) {
-		/* We found it - don't search again. */
-		goto unlock_continue;
-	}
-#endif
 
 	for (i = 0; i < br_lck->num_locks; i++) {
 		struct lock_struct *lock = &locks[i];
@@ -1077,10 +993,6 @@ bool brl_unlock_windows_default(struct byte_range_lock *br_lck,
 		return False;
 	}
 
-#if ZERO_ZERO
-  unlock_continue:
-#endif
-
 	ARRAY_DEL_ELEMENT(locks, i, br_lck->num_locks);
 	br_lck->num_locks -= 1;
 	br_lck->modified = True;