Avoid infinite loop in InvalidateBuffer if we ourselves are holding

tglsfdc · tglsfdc · commit cef01c335597 · 2005-03-18T05:25:23.000Z
a pin on the victim buffer.
diff --git 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 @@ InvalidateBuffer(BufferDesc *buf)
 	{
 		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;
 	}

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.186 2005/03/04 20:21:06 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.187 2005/03/18 05:25:23 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -551,6 +551,9 @@ InvalidateBuffer(BufferDesc *buf)`
`551`	`551`	`{`
`552`	`552`	`UnlockBufHdr_NoHoldoff(buf);`
`553`	`553`	`LWLockRelease(BufMappingLock);`
	`554`	`+ /* safety check: should definitely not be our own pin */`
	`555`	`+ if (PrivateRefCount[buf->buf_id] != 0)`
	`556`	`+ elog(ERROR, "buffer is pinned in InvalidateBuffer");`
`554`	`557`	`WaitIO(buf);`
`555`	`558`	`goto retry;`
`556`	`559`	`}`