From: Thomas Munro <tmunro@postgresql.org>
Date: Thu, 17 Aug 2023 03:45:13 +0000 (+1200)
Subject: Invalidate smgr_targblock in smgrrelease().
X-Git-Tag: REL_17_BETA1~2013
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=81e36d3e0df8d3d7a3daa2e2216f96df23ffc96a;p=thirdparty%2Fpostgresql.git

Invalidate smgr_targblock in smgrrelease().

In rare circumstances involving relfilenode reuse, it might have been
possible for smgr_targblock to finish up pointing past the end.

Oversight in b74e94dc.  Back-patch to 15.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CA%2BhUKGJ8NTvqLHz6dqbQnt2c8XCki4r2QvXjBQcXpVwxTY_pvA%40mail.gmail.com
---

diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index f76c4605dbb..5d0f3d515c3 100644
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -296,6 +296,7 @@ smgrrelease(SMgrRelation reln)
 		smgrsw[reln->smgr_which].smgr_close(reln, forknum);
 		reln->smgr_cached_nblocks[forknum] = InvalidBlockNumber;
 	}
+	reln->smgr_targblock = InvalidBlockNumber;
 }
 
 /*