Avoid infinite loop in InvalidateBuffer if we ourselves are holding

a pin on the victim buffer.

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 59dec8f9ead1da0b9896a93c14e777f60f306a19..bda4544b279c733d1f418dfce5212ca512182f82 100644 (file)
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.186 2005/03/04 20:21:06 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.187 2005/03/18 05:25:23 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -551,6 +551,9 @@ retry:
    {
        UnlockBufHdr_NoHoldoff(buf);
        LWLockRelease(BufMappingLock);
+       /* safety check: should definitely not be our *own* pin */
+       if (PrivateRefCount[buf->buf_id] != 0)
+           elog(ERROR, "buffer is pinned in InvalidateBuffer");
        WaitIO(buf);
        goto retry;
    }