smgr-fix.patch

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Format: unified

File	+	−
src/backend/storage/smgr/smgr.c	18	13
src/include/storage/smgr.h	1	0

diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index 0c0bba4ab3..02a5d5cdda 100644
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -259,7 +259,12 @@ static void
 add_to_unowned_list(SMgrRelation reln)
 {
 	/* place it at head of the list (to make smgrsetowner cheap) */
+	reln->prev_unowned_reln = NULL;
 	reln->next_unowned_reln = first_unowned_reln;
+
+	if (first_unowned_reln)
+		first_unowned_reln->prev_unowned_reln = reln;
+
 	first_unowned_reln = reln;
 }
 
@@ -279,20 +284,20 @@ add_to_unowned_list(SMgrRelation reln)
 static void
 remove_from_unowned_list(SMgrRelation reln)
 {
-	SMgrRelation *link;
-	SMgrRelation cur;
+	SMgrRelation prev;
+	SMgrRelation next;
 
-	for (link = &first_unowned_reln, cur = *link;
-		 cur != NULL;
-		 link = &cur->next_unowned_reln, cur = *link)
-	{
-		if (cur == reln)
-		{
-			*link = cur->next_unowned_reln;
-			cur->next_unowned_reln = NULL;
-			break;
-		}
-	}
+	prev = reln->prev_unowned_reln;
+	next = reln->next_unowned_reln;
+
+	if (prev)
+		prev->next_unowned_reln = reln->next_unowned_reln;
+
+	if (next)
+		next->prev_unowned_reln = reln->prev_unowned_reln;
+
+	if (reln == first_unowned_reln)
+		first_unowned_reln = next;
 }
 
 /*
diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index 820d08ed4e..ed6c4421eb 100644
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -72,6 +72,7 @@ typedef struct SMgrRelationData
 	struct _MdfdVec *md_seg_fds[MAX_FORKNUM + 1];
 
 	/* if unowned, list link in list of all unowned SMgrRelations */
+	struct SMgrRelationData *prev_unowned_reln;
 	struct SMgrRelationData *next_unowned_reln;
 } SMgrRelationData;