? potential bug in LockBuffer ?

Folks:
As I study the source of LockBuffer in bufmgr.c I came across
the following code snippet for the case of releasing a
shared (read) lock:

if (mode == BUFFER_LOCK_UNLOCK)
{
if (*buflock & BL_R_LOCK)
{
Assert(buf->r_locks > 0);
Assert(!(buf->w_lock));
Assert(!(*buflock & (BL_W_LOCK | BL_RI_LOCK)));
(buf->r_locks)--;
*buflock &= ~BL_R_LOCK;

This code resets BL_R_LOCK on the first release of a shared lock.
I think it should check that the count of readers be zero:
( something like

if (mode == BUFFER_LOCK_UNLOCK)
{
if (*buflock & BL_R_LOCK)
{
Assert(buf->r_locks > 0);
Assert(!(buf->w_lock));
Assert(!(*buflock & (BL_W_LOCK | BL_RI_LOCK)));
(buf->r_locks)--;
if (!buf->r_locks)
*buflock &= ~BL_R_LOCK;

Or I am missing something...

thanks
regards
Mauricio
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com