smgr: Make SMgrRelation initialization safer against errors

anarazel · anarazel · commit ee578921b60e · 2025-03-18T13:44:10.000-04:00
In case the smgr_open callback failed, the ->pincount field would not be initialized and the relation would not be put onto the unpinned_relns list. This buglet was introduced in 21d9c3e, in 17. Discussion: https://postgr.es/m/3vae7l5ozvqtxmd7rr7zaeq3qkuipz365u3rtim5t5wdkr6f4g@vkgf2fogjirl Backpatch-through: 17
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
@@ -231,12 +231,12 @@ smgropen(RelFileLocator rlocator, ProcNumber backend)
 			reln->smgr_cached_nblocks[i] = InvalidBlockNumber;
 		reln->smgr_which = 0;	/* we only have md.c at present */
 
-		/* implementation-specific initialization */
-		smgrsw[reln->smgr_which].smgr_open(reln);
-
 		/* it is not pinned yet */
 		reln->pincount = 0;
 		dlist_push_tail(&unpinned_relns, &reln->node);
+
+		/* implementation-specific initialization */
+		smgrsw[reln->smgr_which].smgr_open(reln);
 	}
 
 	return reln;
