Avoid erroring out when unable to remove or parse logical rewrite files to save checkpoint work

From 4148b0756058ad42367b9758284af1cfefbd023e Mon Sep 17 00:00:00 2001
From: Nathan Bossart <bossartn@amazon.com>
Date: Thu, 20 Jan 2022 19:03:03 +0000
Subject: [PATCH v2 1/1] fix up code in directory scans for logical replication

---
 src/backend/access/heap/rewriteheap.c           | 44 ++++++++++++++++++++-----
 src/backend/replication/logical/reorderbuffer.c |  4 ---
 src/backend/replication/logical/snapbuild.c     |  9 +++--
 3 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index aa265edf60..f1df361e06 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1222,31 +1222,49 @@ CheckPointLogicalRewriteHeap(void)
 		uint32		hi,
 					lo;
 
-		if (strcmp(mapping_de->d_name, ".") == 0 ||
-			strcmp(mapping_de->d_name, "..") == 0)
+		/* Skip over files that cannot be ours. */
+		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-			continue;
-
-		/* Skip over files that cannot be ours. */
-		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
+		if (lstat(path, &statbuf) != 0)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", path)));
+		else if (!S_ISREG(statbuf.st_mode))
 			continue;
 
+		/*
+		 * We just log a message if a file doesn't fit the pattern, it's
+		 * probably some editor's lock/state file or similar...
+		 */
 		if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
 				   &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
-			elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
+		{
+			ereport(LOG,
+					(errmsg("could not parse file name \"%s\"",
+							mapping_de->d_name)));
+			continue;
+		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
 		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
 		{
 			elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
+
+			/*
+			 * It's not particularly harmful, though strange, if we can't
+			 * remove the file here. Don't prevent the checkpoint from
+			 * completing, that'd be a cure worse than the disease.
+			 */
 			if (unlink(path) < 0)
-				ereport(ERROR,
+			{
+				ereport(LOG,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m", path)));
+				continue;
+			}
 		}
 		else
 		{
@@ -1267,6 +1285,11 @@ CheckPointLogicalRewriteHeap(void)
 			 * We could try to avoid fsyncing files that either haven't
 			 * changed or have only been created since the checkpoint's start,
 			 * but it's currently not deemed worth the effort.
+			 *
+			 * Unlike failures to unlink() old logical rewrite files, we must
+			 * ERROR if we're unable to sync transient state down to disk.  This
+			 * allows replay to assume that everything written out before
+			 * checkpoint start is persisted.
 			 */
 			pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_CHECKPOINT_SYNC);
 			if (pg_fsync(fd) != 0)
@@ -1282,4 +1305,7 @@ CheckPointLogicalRewriteHeap(void)
 		}
 	}
 	FreeDir(mappings_dir);
+
+	/* persist directory entries to disk */
+	fsync_fname("pg_logical/mappings", true);
 }
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index d317a626e1..6fb4b35d89 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -5028,10 +5028,6 @@ UpdateLogicalMappings(HTAB *tuplecid_data, Oid relid, Snapshot snapshot)
 					f_lo;
 		RewriteMappingFile *f;
 
-		if (strcmp(mapping_de->d_name, ".") == 0 ||
-			strcmp(mapping_de->d_name, "..") == 0)
-			continue;
-
 		/* Ignore files that aren't ours */
 		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
 			continue;
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index ab04e946bc..f9e26e96c7 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1954,8 +1954,11 @@ CheckPointSnapBuild(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (lstat(path, &statbuf) != 0)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", path)));
+		else if (!S_ISREG(statbuf.st_mode))
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
@@ -1968,7 +1971,7 @@ CheckPointSnapBuild(void)
 		 * currently being written that are older than cutoff.
 		 *
 		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
+		 * probably some editor's lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
 		{
-- 
2.16.6

From dc9dcd3e8e8b648ef410c1b01d63a6c7bd41f94b Mon Sep 17 00:00:00 2001
From: Nathan Bossart <bossartn@amazon.com>
Date: Thu, 20 Jan 2022 20:32:39 +0000
Subject: [PATCH v3 1/1] persist directory entries for logical rewrite files to
 disk during checkpoints

---
 src/backend/access/heap/rewriteheap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index aa265edf60..2a53826736 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1282,4 +1282,7 @@ CheckPointLogicalRewriteHeap(void)
 		}
 	}
 	FreeDir(mappings_dir);
+
+	/* persist directory entries to disk */
+	fsync_fname("pg_logical/mappings", true);
 }
-- 
2.16.6

From df7a07d27c2858ec3ac383335af3e55e5428e3b1 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Wed, 26 Jan 2022 14:03:11 -0800
Subject: [PATCH v4 1/2] add error checking for calls to lstat() in replication
 code

---
 src/backend/access/heap/rewriteheap.c           | 6 +++++-
 src/backend/replication/logical/reorderbuffer.c | 6 +++++-
 src/backend/replication/logical/snapbuild.c     | 6 +++++-
 src/backend/replication/slot.c                  | 6 +++++-
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..81319e0c78 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1227,7 +1227,11 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (lstat(path, &statbuf) != 0)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", path)));
+		else if (!S_ISREG(statbuf.st_mode))
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 19b2ba2000..d8d784a42f 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -4407,7 +4407,11 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 	sprintf(path, "pg_replslot/%s", slotname);
 
 	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+	if (lstat(path, &statbuf) != 0)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not stat file \"%s\": %m", path)));
+	else if (!S_ISDIR(statbuf.st_mode))
 		return;
 
 	spill_dir = AllocateDir(path);
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..57f5a5e81f 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1955,7 +1955,11 @@ CheckPointSnapBuild(void)
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (lstat(path, &statbuf) != 0)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", path)));
+		else if (!S_ISREG(statbuf.st_mode))
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index e5e0cf8768..21fb7536e2 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1413,7 +1413,11 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (lstat(path, &statbuf) != 0)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not stat file \"%s\": %m", path)));
+		else if (!S_ISDIR(statbuf.st_mode))
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
-- 
2.25.1

From 28a06a2cb84102a92da3fca0f0055dd67902d7de Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Wed, 26 Jan 2022 16:24:04 -0800
Subject: [PATCH v4 2/2] minor improvements to replication code

---
 src/backend/replication/logical/snapbuild.c | 19 ++-----------------
 src/backend/replication/slot.c              |  5 +----
 2 files changed, 3 insertions(+), 21 deletions(-)

diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 57f5a5e81f..ce6cb85c1a 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1970,16 +1970,10 @@ CheckPointSnapBuild(void)
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
-		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
-		{
-			ereport(LOG,
+			ereport(ERROR,
 					(errmsg("could not parse file name \"%s\"", path)));
-			continue;
-		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
@@ -1987,20 +1981,11 @@ CheckPointSnapBuild(void)
 		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
 		{
 			elog(DEBUG1, "removing snapbuild snapshot %s", path);
-
-			/*
-			 * It's not particularly harmful, though strange, if we can't
-			 * remove the file here. Don't prevent the checkpoint from
-			 * completing, that'd be a cure worse than the disease.
-			 */
 			if (unlink(path) < 0)
-			{
-				ereport(LOG,
+				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m",
 								path)));
-				continue;
-			}
 		}
 	}
 	FreeDir(snap_dir);
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 21fb7536e2..37ec3fa633 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1424,12 +1424,9 @@ StartupReplicationSlots(void)
 		if (pg_str_endswith(replication_de->d_name, ".tmp"))
 		{
 			if (!rmtree(path, true))
-			{
-				ereport(WARNING,
+				ereport(ERROR,
 						(errmsg("could not remove directory \"%s\"",
 								path)));
-				continue;
-			}
 			fsync_fname("pg_replslot", true);
 			continue;
 		}
-- 
2.25.1

From b5358ad720caa4af5fe8635920ab5853afd5a327 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Mon, 31 Jan 2022 05:05:22 +0000
Subject: [PATCH v5] Replace ReadDir with ReadDirExtended

Replace ReadDir with ReadDirExtended and get rid of lstat entirely.
With this change, the checkpoint will only care about the snapshot
and mapping files and not fail if it finds other files in the
directories.

Removing lstat enables us to make things faster as we avoid extra
system calls.

Also, convert "could not parse filename" and "could not remove file"
errors to LOG messages in  CheckPointLogicalRewriteHeap. This will
enable checkpoint not to waste the amount of work that it had done.
---
 src/backend/access/heap/rewriteheap.c       | 25 ++++++++++++++++-----
 src/backend/replication/logical/snapbuild.c |  9 +-------
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..2cb72a2a5c 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1211,9 +1211,8 @@ CheckPointLogicalRewriteHeap(void)
 		cutoff = redo;
 
 	mappings_dir = AllocateDir("pg_logical/mappings");
-	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
+	while ((mapping_de = ReadDirExtended(mappings_dir, "pg_logical/mappings", LOG)) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,26 +1226,40 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-			continue;
 
 		/* Skip over files that cannot be ours. */
 		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
 			continue;
 
+		/*
+		 * We just log a message if a file doesn't fit the pattern, it's
+		 * probably some editors lock/state file or similar...
+		 */
 		if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
 				   &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
-			elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
+		{
+			elog(LOG, "could not parse filename \"%s\"", mapping_de->d_name);
+			continue;
+		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
 		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
 		{
 			elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
+
+			/*
+			 * It's not particularly harmful, though strange, if we can't
+			 * remove the file here. Don't prevent the checkpoint from
+			 * completing, that'd be a cure worse than the disease.
+			 */
 			if (unlink(path) < 0)
-				ereport(ERROR,
+			{
+				ereport(LOG,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m", path)));
+				continue;
+			}
 		}
 		else
 		{
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..a4bf7a7fd9 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1942,12 +1942,11 @@ CheckPointSnapBuild(void)
 		cutoff = redo;
 
 	snap_dir = AllocateDir("pg_logical/snapshots");
-	while ((snap_de = ReadDir(snap_dir, "pg_logical/snapshots")) != NULL)
+	while ((snap_de = ReadDirExtended(snap_dir, "pg_logical/snapshots", LOG)) != NULL)
 	{
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
@@ -1955,12 +1954,6 @@ CheckPointSnapBuild(void)
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-		{
-			elog(DEBUG1, "only regular files expected: %s", path);
-			continue;
-		}
-
 		/*
 		 * temporary filenames from SnapBuildSerialize() include the LSN and
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
-- 
2.25.1

From 0716e03efb41a7d99872889cafbed802e326e92a Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 2 Feb 2022 11:47:10 +0000
Subject: [PATCH v6] Replace ReadDir with ReadDirExtended

Replace ReadDir with ReadDirExtended and get rid of lstat entirely.
With this change, the checkpoint will only care about the snapshot
and mapping files and not fail if it finds other files in the
directories.

Removing lstat enables us to make things faster as we avoid extra
system calls.

Also, convert "could not parse filename" and "could not remove file"
errors to LOG messages in  CheckPointLogicalRewriteHeap. This will
enable checkpoint not to waste the amount of work that it had done.
---
 src/backend/access/heap/rewriteheap.c       | 29 ++++++++++++++++-----
 src/backend/replication/logical/snapbuild.c |  9 +------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..b028b98eaa 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1211,9 +1211,8 @@ CheckPointLogicalRewriteHeap(void)
 		cutoff = redo;
 
 	mappings_dir = AllocateDir("pg_logical/mappings");
-	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
+	while ((mapping_de = ReadDirExtended(mappings_dir, "pg_logical/mappings", LOG)) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,26 +1226,42 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-			continue;
 
 		/* Skip over files that cannot be ours. */
 		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
 			continue;
 
+		/*
+		 * We just log a message if a file doesn't fit the pattern, it's
+		 * probably some editors lock/state file or similar...
+		 */
 		if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
 				   &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
-			elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
+		{
+			ereport(LOG,
+					(errmsg("could not parse file name \"%s\"", path)));
+			continue;
+		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
 		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
 		{
 			elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
+
+			/*
+			 * It's not particularly harmful, though strange, if we can't
+			 * remove the file here. Don't prevent the checkpoint from
+			 * completing, that'd be a cure worse than the disease.
+			 */
 			if (unlink(path) < 0)
-				ereport(ERROR,
+			{
+				ereport(LOG,
 						(errcode_for_file_access(),
-						 errmsg("could not remove file \"%s\": %m", path)));
+						 errmsg("could not remove file \"%s\": %m",
+								path)));
+				continue;
+			}
 		}
 		else
 		{
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..a4bf7a7fd9 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1942,12 +1942,11 @@ CheckPointSnapBuild(void)
 		cutoff = redo;
 
 	snap_dir = AllocateDir("pg_logical/snapshots");
-	while ((snap_de = ReadDir(snap_dir, "pg_logical/snapshots")) != NULL)
+	while ((snap_de = ReadDirExtended(snap_dir, "pg_logical/snapshots", LOG)) != NULL)
 	{
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
@@ -1955,12 +1954,6 @@ CheckPointSnapBuild(void)
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-		{
-			elog(DEBUG1, "only regular files expected: %s", path);
-			continue;
-		}
-
 		/*
 		 * temporary filenames from SnapBuildSerialize() include the LSN and
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
-- 
2.25.1

From aef9d67db637d9e9bd7e9b7c2381e952a891e141 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Thu, 3 Feb 2022 04:13:00 +0000
Subject: [PATCH v7] Replace ReadDir with ReadDirExtended

Replace ReadDir with ReadDirExtended (in CheckPointSnapBuild) and
get rid of lstat entirely. We still use ReadDir in CheckPointLogicalRewriteHeap
because unable to read directory would result a NULL from
ReadDirExtended and we may miss to fsync the remaining map files,
so here let's error out with ReadDir.

With this change, the checkpoint will only care about the snapshot
and mapping files and not fail if it finds other files in the
directories.

Removing lstat enables us to make things faster as we avoid extra
system calls.

Also, convert "could not parse filename" and "could not remove file"
errors to LOG messages in  CheckPointLogicalRewriteHeap. This will
enable checkpoint not to waste the amount of work that it had done.
---
 src/backend/access/heap/rewriteheap.c       | 27 ++++++++++++++++-----
 src/backend/replication/logical/snapbuild.c |  9 +------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..24e7a35881 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1213,7 +1213,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,26 +1226,42 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-			continue;
 
 		/* Skip over files that cannot be ours. */
 		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
 			continue;
 
+		/*
+		 * We just log a message if a file doesn't fit the pattern, it's
+		 * probably some editors lock/state file or similar...
+		 */
 		if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
 				   &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
-			elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
+		{
+			ereport(LOG,
+					(errmsg("could not parse file name \"%s\"", path)));
+			continue;
+		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
 		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
 		{
 			elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
+
+			/*
+			 * It's not particularly harmful, though strange, if we can't
+			 * remove the file here. Don't prevent the checkpoint from
+			 * completing, that'd be a cure worse than the disease.
+			 */
 			if (unlink(path) < 0)
-				ereport(ERROR,
+			{
+				ereport(LOG,
 						(errcode_for_file_access(),
-						 errmsg("could not remove file \"%s\": %m", path)));
+						 errmsg("could not remove file \"%s\": %m",
+								path)));
+				continue;
+			}
 		}
 		else
 		{
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..a4bf7a7fd9 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1942,12 +1942,11 @@ CheckPointSnapBuild(void)
 		cutoff = redo;
 
 	snap_dir = AllocateDir("pg_logical/snapshots");
-	while ((snap_de = ReadDir(snap_dir, "pg_logical/snapshots")) != NULL)
+	while ((snap_de = ReadDirExtended(snap_dir, "pg_logical/snapshots", LOG)) != NULL)
 	{
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
@@ -1955,12 +1954,6 @@ CheckPointSnapBuild(void)
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-		{
-			elog(DEBUG1, "only regular files expected: %s", path);
-			continue;
-		}
-
 		/*
 		 * temporary filenames from SnapBuildSerialize() include the LSN and
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
-- 
2.25.1

From 4801ff2c3b1e7bc7076205b676d4e3bc4a4ed308 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Thu, 10 Feb 2022 15:58:58 +0000
Subject: [PATCH v8] Replace ReadDir with ReadDirExtended

Replace ReadDir with ReadDirExtended (in CheckPointSnapBuild) and
get rid of lstat entirely. We still use ReadDir in CheckPointLogicalRewriteHeap
because unable to read directory would result a NULL from
ReadDirExtended and we may miss to fsync the remaining map files,
so here let's error out with ReadDir.

With this change, the checkpoint will only care about the snapshot
and mapping files and not fail if it finds other files in the
directories.

Removing lstat enables us to make things faster as we avoid extra
system calls.

Also, convert "could not parse filename" and "could not remove file"
errors to LOG messages in  CheckPointLogicalRewriteHeap. This will
enable checkpoint not to waste the amount of work that it had done.
---
 src/backend/access/heap/rewriteheap.c       | 24 +++++++++++++++------
 src/backend/replication/logical/snapbuild.c | 12 ++---------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..035cd6db70 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1213,7 +1213,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,26 +1226,39 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-			continue;
 
 		/* Skip over files that cannot be ours. */
 		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
 			continue;
 
+		/* We just log a message if a file doesn't fit the pattern. */
 		if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
 				   &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
-			elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
+		{
+			ereport(LOG,
+					(errmsg("could not parse file name \"%s\"", path)));
+			continue;
+		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
 		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
 		{
 			elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
+
+			/*
+			 * It's not particularly harmful, though strange, if we can't
+			 * remove the file here. Don't prevent the checkpoint from
+			 * completing, that'd be a cure worse than the disease.
+			 */
 			if (unlink(path) < 0)
-				ereport(ERROR,
+			{
+				ereport(LOG,
 						(errcode_for_file_access(),
-						 errmsg("could not remove file \"%s\": %m", path)));
+						 errmsg("could not remove file \"%s\": %m",
+								path)));
+				continue;
+			}
 		}
 		else
 		{
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..e2cdf17bee 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1942,12 +1942,11 @@ CheckPointSnapBuild(void)
 		cutoff = redo;
 
 	snap_dir = AllocateDir("pg_logical/snapshots");
-	while ((snap_de = ReadDir(snap_dir, "pg_logical/snapshots")) != NULL)
+	while ((snap_de = ReadDirExtended(snap_dir, "pg_logical/snapshots", LOG)) != NULL)
 	{
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
@@ -1955,20 +1954,13 @@ CheckPointSnapBuild(void)
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
-		{
-			elog(DEBUG1, "only regular files expected: %s", path);
-			continue;
-		}
-
 		/*
 		 * temporary filenames from SnapBuildSerialize() include the LSN and
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
 		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
+		 * We just log a message if a file doesn't fit the pattern.
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
 		{
-- 
2.25.1

From 8dddbf0241258e7b52ab664e077193d5008ee6cd Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:40:53 -0800
Subject: [PATCH v9 1/3] make use of get_dirent_type() in replication code

---
 src/backend/access/heap/rewriteheap.c       | 4 ++--
 src/backend/replication/logical/snapbuild.c | 5 ++---
 src/backend/replication/slot.c              | 4 ++--
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..d64d7aae2e 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, ERROR) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..df50abfd98 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1947,15 +1948,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, ERROR) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 5da5fa825a..480a26bc7f 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1428,7 +1429,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1438,7 +1438,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, ERROR) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
-- 
2.25.1

From 1cb3fdc3e7ed323691ec37b76b95055ad9af9757 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:46:44 -0800
Subject: [PATCH v9 2/3] add error checking for call to lstat() in replication
 code

---
 src/backend/replication/logical/reorderbuffer.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index c2d9be81fa..9b9e15858e 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -4812,7 +4812,11 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 	sprintf(path, "pg_replslot/%s", slotname);
 
 	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+	if (lstat(path, &statbuf) != 0)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not stat file \"%s\": %m", path)));
+	else if (!S_ISDIR(statbuf.st_mode))
 		return;
 
 	spill_dir = AllocateDir(path);
-- 
2.25.1

From 7d2bed2e783aab2506bae27d1e4df90cc1b65dd4 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:53:58 -0800
Subject: [PATCH v9 3/3] minor improvements to replication code

---
 src/backend/replication/logical/snapbuild.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index df50abfd98..6a60e942b7 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1965,16 +1965,10 @@ CheckPointSnapBuild(void)
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
-		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
-		{
-			ereport(LOG,
+			ereport(ERROR,
 					(errmsg("could not parse file name \"%s\"", path)));
-			continue;
-		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
@@ -1983,19 +1977,11 @@ CheckPointSnapBuild(void)
 		{
 			elog(DEBUG1, "removing snapbuild snapshot %s", path);
 
-			/*
-			 * It's not particularly harmful, though strange, if we can't
-			 * remove the file here. Don't prevent the checkpoint from
-			 * completing, that'd be a cure worse than the disease.
-			 */
 			if (unlink(path) < 0)
-			{
-				ereport(LOG,
+				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m",
 								path)));
-				continue;
-			}
 		}
 	}
 	FreeDir(snap_dir);
-- 
2.25.1

From 23db5cb9bf04519b9341b6195ca224e0f8bc03cb Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:40:53 -0800
Subject: [PATCH v10 1/3] make more use of get_dirent_type()

---
 src/backend/access/heap/rewriteheap.c       |  4 +-
 src/backend/replication/logical/snapbuild.c |  5 +--
 src/backend/replication/slot.c              |  4 +-
 src/backend/storage/file/copydir.c          | 21 +++--------
 src/backend/storage/file/fd.c               | 20 +++++-----
 src/backend/utils/misc/guc-file.l           | 42 ++++++++-------------
 src/timezone/pgtz.c                         |  8 +---
 7 files changed, 41 insertions(+), 63 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..d64d7aae2e 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, ERROR) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..df50abfd98 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1947,15 +1948,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, ERROR) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 5da5fa825a..480a26bc7f 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1428,7 +1429,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1438,7 +1438,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, ERROR) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 14b77f2861..4a4a79b40a 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2783,6 +2783,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2798,6 +2802,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3234,17 +3242,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index c70543fa74..8f10252fa4 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1018,7 +1019,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1035,32 +1036,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1068,6 +1046,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.25.1

From 70c3ab552e729aeb84b006d0fdfa0df0e524b277 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:46:44 -0800
Subject: [PATCH v10 2/3] add error checking for call to lstat() in replication
 code

---
 src/backend/replication/logical/reorderbuffer.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index c2d9be81fa..9b9e15858e 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -4812,7 +4812,11 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 	sprintf(path, "pg_replslot/%s", slotname);
 
 	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+	if (lstat(path, &statbuf) != 0)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not stat file \"%s\": %m", path)));
+	else if (!S_ISDIR(statbuf.st_mode))
 		return;
 
 	spill_dir = AllocateDir(path);
-- 
2.25.1

From d71585d0baca6c08be499fa7b6d42517e952d488 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:53:58 -0800
Subject: [PATCH v10 3/3] minor improvements to replication code

---
 src/backend/replication/logical/snapbuild.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index df50abfd98..6a60e942b7 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1965,16 +1965,10 @@ CheckPointSnapBuild(void)
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
-		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
-		{
-			ereport(LOG,
+			ereport(ERROR,
 					(errmsg("could not parse file name \"%s\"", path)));
-			continue;
-		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
@@ -1983,19 +1977,11 @@ CheckPointSnapBuild(void)
 		{
 			elog(DEBUG1, "removing snapbuild snapshot %s", path);
 
-			/*
-			 * It's not particularly harmful, though strange, if we can't
-			 * remove the file here. Don't prevent the checkpoint from
-			 * completing, that'd be a cure worse than the disease.
-			 */
 			if (unlink(path) < 0)
-			{
-				ereport(LOG,
+				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m",
 								path)));
-				continue;
-			}
 		}
 	}
 	FreeDir(snap_dir);
-- 
2.25.1

From 784419919fca8f157a1c7304b79567b3ba29f3bf Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:40:53 -0800
Subject: [PATCH v11 1/2] make more use of get_dirent_type()

---
 src/backend/access/heap/rewriteheap.c         |  4 +-
 .../replication/logical/reorderbuffer.c       | 12 +++---
 src/backend/replication/logical/snapbuild.c   |  5 +--
 src/backend/replication/slot.c                |  4 +-
 src/backend/storage/file/copydir.c            | 21 +++-------
 src/backend/storage/file/fd.c                 | 20 +++++----
 src/backend/utils/misc/guc-file.l             | 42 +++++++------------
 src/timezone/pgtz.c                           |  8 +---
 8 files changed, 48 insertions(+), 68 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..d64d7aae2e 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, ERROR) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index c2d9be81fa..489a8300fa 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -126,6 +126,7 @@
 #include "access/xlog_internal.h"
 #include "catalog/catalog.h"
 #include "commands/sequence.h"
+#include "common/file_utils.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -4806,15 +4807,10 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 {
 	DIR		   *spill_dir;
 	struct dirent *spill_de;
-	struct stat statbuf;
 	char		path[MAXPGPATH * 2 + 12];
 
 	sprintf(path, "pg_replslot/%s", slotname);
 
-	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
-		return;
-
 	spill_dir = AllocateDir(path);
 	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
 	{
@@ -4862,6 +4858,7 @@ StartupReorderBuffer(void)
 {
 	DIR		   *logical_dir;
 	struct dirent *logical_de;
+	char		path[MAXPGPATH * 2 + 12];
 
 	logical_dir = AllocateDir("pg_replslot");
 	while ((logical_de = ReadDir(logical_dir, "pg_replslot")) != NULL)
@@ -4874,6 +4871,11 @@ StartupReorderBuffer(void)
 		if (!ReplicationSlotValidateName(logical_de->d_name, DEBUG2))
 			continue;
 
+		/* we're only handling directories here, skip if it's not ours */
+		sprintf(path, "pg_replslot/%s", logical_de->d_name);
+		if (get_dirent_type(path, logical_de, false, ERROR) != PGFILETYPE_DIR)
+			continue;
+
 		/*
 		 * ok, has to be a surviving logical slot, iterate and delete
 		 * everything starting with xid-*
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..df50abfd98 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1947,15 +1948,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, ERROR) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index ed4c8b3ad5..3748a5f314 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1471,7 +1472,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1481,7 +1481,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, ERROR) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 14b77f2861..4a4a79b40a 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2783,6 +2783,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2798,6 +2802,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3234,17 +3242,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index c70543fa74..8f10252fa4 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1018,7 +1019,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1035,32 +1036,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1068,6 +1046,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.25.1

From 5f8a5562664a56fdd16e2983ba4f86692baa5217 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:53:58 -0800
Subject: [PATCH v11 2/2] minor improvements to replication code

---
 .../replication/logical/reorderbuffer.c        |  2 +-
 src/backend/replication/logical/snapbuild.c    | 18 ++----------------
 2 files changed, 3 insertions(+), 17 deletions(-)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 489a8300fa..87c4ed3560 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -4812,7 +4812,7 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 	sprintf(path, "pg_replslot/%s", slotname);
 
 	spill_dir = AllocateDir(path);
-	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
+	while ((spill_de = ReadDir(spill_dir, path)) != NULL)
 	{
 		/* only look at names that can be ours */
 		if (strncmp(spill_de->d_name, "xid", 3) == 0)
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index df50abfd98..6a60e942b7 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1965,16 +1965,10 @@ CheckPointSnapBuild(void)
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
-		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
-		{
-			ereport(LOG,
+			ereport(ERROR,
 					(errmsg("could not parse file name \"%s\"", path)));
-			continue;
-		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
@@ -1983,19 +1977,11 @@ CheckPointSnapBuild(void)
 		{
 			elog(DEBUG1, "removing snapbuild snapshot %s", path);
 
-			/*
-			 * It's not particularly harmful, though strange, if we can't
-			 * remove the file here. Don't prevent the checkpoint from
-			 * completing, that'd be a cure worse than the disease.
-			 */
 			if (unlink(path) < 0)
-			{
-				ereport(LOG,
+				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m",
 								path)));
-				continue;
-			}
 		}
 	}
 	FreeDir(snap_dir);
-- 
2.25.1

From a92ccf47c9c334eea5b8d07b8fcab7031181c37e Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:40:53 -0800
Subject: [PATCH v12 1/2] make more use of get_dirent_type()

---
 src/backend/access/heap/rewriteheap.c         |  4 +-
 .../replication/logical/reorderbuffer.c       | 12 +++---
 src/backend/replication/logical/snapbuild.c   |  5 +--
 src/backend/replication/slot.c                |  4 +-
 src/backend/storage/file/copydir.c            | 21 +++-------
 src/backend/storage/file/fd.c                 | 20 +++++----
 src/backend/utils/misc/guc-file.l             | 42 +++++++------------
 src/timezone/pgtz.c                           |  8 +---
 8 files changed, 48 insertions(+), 68 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 2a53826736..d64d7aae2e 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, ERROR) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 5adc016d44..63ef55f3f7 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -91,6 +91,7 @@
 #include "access/xact.h"
 #include "access/xlog_internal.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -4408,15 +4409,10 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 {
 	DIR		   *spill_dir;
 	struct dirent *spill_de;
-	struct stat statbuf;
 	char		path[MAXPGPATH * 2 + 12];
 
 	sprintf(path, "pg_replslot/%s", slotname);
 
-	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
-		return;
-
 	spill_dir = AllocateDir(path);
 	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
 	{
@@ -4464,6 +4460,7 @@ StartupReorderBuffer(void)
 {
 	DIR		   *logical_dir;
 	struct dirent *logical_de;
+	char		path[MAXPGPATH * 2 + 12];
 
 	logical_dir = AllocateDir("pg_replslot");
 	while ((logical_de = ReadDir(logical_dir, "pg_replslot")) != NULL)
@@ -4476,6 +4473,11 @@ StartupReorderBuffer(void)
 		if (!ReplicationSlotValidateName(logical_de->d_name, DEBUG2))
 			continue;
 
+		/* we're only handling directories here, skip if it's not ours */
+		sprintf(path, "pg_replslot/%s", logical_de->d_name);
+		if (get_dirent_type(path, logical_de, false, ERROR) != PGFILETYPE_DIR)
+			continue;
+
 		/*
 		 * ok, has to be a surviving logical slot, iterate and delete
 		 * everything starting with xid-*
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 83fca8a77d..df50abfd98 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1947,15 +1948,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, ERROR) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index c35ea7c35b..5ee68e71b8 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1485,7 +1486,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1495,7 +1495,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, ERROR) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 14b77f2861..4a4a79b40a 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2783,6 +2783,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2798,6 +2802,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3234,17 +3242,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index c70543fa74..8f10252fa4 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1018,7 +1019,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1035,32 +1036,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1068,6 +1046,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.25.1

From 96b3c44bf9850b106751facd1e7d2d77543fe9d4 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Tue, 15 Feb 2022 09:53:58 -0800
Subject: [PATCH v12 2/2] minor improvements to replication code

---
 .../replication/logical/reorderbuffer.c        |  2 +-
 src/backend/replication/logical/snapbuild.c    | 18 ++----------------
 2 files changed, 3 insertions(+), 17 deletions(-)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 63ef55f3f7..532c3e4630 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -4414,7 +4414,7 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 	sprintf(path, "pg_replslot/%s", slotname);
 
 	spill_dir = AllocateDir(path);
-	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
+	while ((spill_de = ReadDir(spill_dir, path)) != NULL)
 	{
 		/* only look at names that can be ours */
 		if (strncmp(spill_de->d_name, "xid", 3) == 0)
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index df50abfd98..6a60e942b7 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1965,16 +1965,10 @@ CheckPointSnapBuild(void)
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
-		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
-		{
-			ereport(LOG,
+			ereport(ERROR,
 					(errmsg("could not parse file name \"%s\"", path)));
-			continue;
-		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
@@ -1983,19 +1977,11 @@ CheckPointSnapBuild(void)
 		{
 			elog(DEBUG1, "removing snapbuild snapshot %s", path);
 
-			/*
-			 * It's not particularly harmful, though strange, if we can't
-			 * remove the file here. Don't prevent the checkpoint from
-			 * completing, that'd be a cure worse than the disease.
-			 */
 			if (unlink(path) < 0)
-			{
-				ereport(LOG,
+				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m",
 								path)));
-				continue;
-			}
 		}
 	}
 	FreeDir(snap_dir);
-- 
2.25.1

From f0be5188830655b9ce9375b6d13b1ca728dbfcdd Mon Sep 17 00:00:00 2001
From: Thomas Munro <tmunro@postgresql.org>
Date: Tue, 9 Aug 2022 13:11:08 +1200
Subject: [PATCH v13 1/2] Make more use of get_dirent_type().

We don't need to call stat() or lstat() in several ReadDir() loops, if
d_type is available, as it usually is on most systems.  If not,
get_dirent_type() will do that under the covers.

In a couple of places this will now raise an ERROR if an internal
stat/lstat fails, where previously errors were silently ignored.  ENOENT
was not expected in these locations, because the loop in question is the
one responsible for unlinking files during checkpoint, or runs at
startup.

Author: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220215231123.GA2584239%40nathanxps13
---
 src/backend/access/heap/rewriteheap.c         |  4 +-
 .../replication/logical/reorderbuffer.c       | 12 +++---
 src/backend/replication/logical/snapbuild.c   |  5 +--
 src/backend/replication/slot.c                |  4 +-
 src/backend/storage/file/copydir.c            | 21 +++-------
 src/backend/storage/file/fd.c                 | 20 +++++----
 src/backend/utils/misc/guc-file.l             | 42 +++++++------------
 src/timezone/pgtz.c                           |  8 +---
 8 files changed, 48 insertions(+), 68 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 9dd885d936..525039d5b2 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, ERROR) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 88a37fde72..f2b6cdf473 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -91,6 +91,7 @@
 #include "access/xact.h"
 #include "access/xlog_internal.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -4407,15 +4408,10 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 {
 	DIR		   *spill_dir;
 	struct dirent *spill_de;
-	struct stat statbuf;
 	char		path[MAXPGPATH * 2 + 12];
 
 	sprintf(path, "pg_replslot/%s", slotname);
 
-	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
-		return;
-
 	spill_dir = AllocateDir(path);
 	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
 	{
@@ -4463,6 +4459,7 @@ StartupReorderBuffer(void)
 {
 	DIR		   *logical_dir;
 	struct dirent *logical_de;
+	char		path[MAXPGPATH * 2 + 12];
 
 	logical_dir = AllocateDir("pg_replslot");
 	while ((logical_de = ReadDir(logical_dir, "pg_replslot")) != NULL)
@@ -4475,6 +4472,11 @@ StartupReorderBuffer(void)
 		if (!ReplicationSlotValidateName(logical_de->d_name, DEBUG2))
 			continue;
 
+		/* we're only handling directories here, skip if it's not one */
+		sprintf(path, "pg_replslot/%s", logical_de->d_name);
+		if (get_dirent_type(path, logical_de, false, ERROR) != PGFILETYPE_DIR)
+			continue;
+
 		/*
 		 * ok, has to be a surviving logical slot, iterate and delete
 		 * everything starting with xid-*
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 73c0f15214..8587e2de43 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1946,15 +1947,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, ERROR) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 850b74936f..bc51e816f9 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1442,7 +1443,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1452,7 +1452,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, ERROR) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index efb34d4dcb..64764a287d 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2708,6 +2708,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2723,6 +2727,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3159,17 +3167,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index ce5633844c..88460422dd 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1017,7 +1018,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1034,32 +1035,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1067,6 +1045,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.35.1

From 3e60b8362eaa5fc50093c3fc59bc16773dda550a Mon Sep 17 00:00:00 2001
From: Thomas Munro <tmunro@postgresql.org>
Date: Tue, 9 Aug 2022 14:42:10 +1200
Subject: [PATCH v13 2/2] Harden errors on some unexpected filesystem
 conditions.

CheckPointSnapBuild() shouldn't fail to unlink() files.  Raise an ERROR,
there's something wrong with the filesystem.  There is also no reason to
tolerate random stray files under pg_logical/snapshots.

ReorderBufferCleanupSerializedTXNs() shouldn't be called for a
non-directory, so raise an ERROR if opendir() fails, there's something
wrong with the filesystem.

Author: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220215231123.GA2584239%40nathanxps13
---
 .../replication/logical/reorderbuffer.c        |  2 +-
 src/backend/replication/logical/snapbuild.c    | 18 ++----------------
 2 files changed, 3 insertions(+), 17 deletions(-)

diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index f2b6cdf473..a80cbacd9b 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -4413,7 +4413,7 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 	sprintf(path, "pg_replslot/%s", slotname);
 
 	spill_dir = AllocateDir(path);
-	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
+	while ((spill_de = ReadDir(spill_dir, path)) != NULL)
 	{
 		/* only look at names that can be ours */
 		if (strncmp(spill_de->d_name, "xid", 3) == 0)
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 8587e2de43..bb788e1adc 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -1964,16 +1964,10 @@ CheckPointSnapBuild(void)
 		 * everything but are postfixed by .$pid.tmp. We can just remove them
 		 * the same as other files because there can be none that are
 		 * currently being written that are older than cutoff.
-		 *
-		 * We just log a message if a file doesn't fit the pattern, it's
-		 * probably some editors lock/state file or similar...
 		 */
 		if (sscanf(snap_de->d_name, "%X-%X.snap", &hi, &lo) != 2)
-		{
-			ereport(LOG,
+			ereport(ERROR,
 					(errmsg("could not parse file name \"%s\"", path)));
-			continue;
-		}
 
 		lsn = ((uint64) hi) << 32 | lo;
 
@@ -1982,19 +1976,11 @@ CheckPointSnapBuild(void)
 		{
 			elog(DEBUG1, "removing snapbuild snapshot %s", path);
 
-			/*
-			 * It's not particularly harmful, though strange, if we can't
-			 * remove the file here. Don't prevent the checkpoint from
-			 * completing, that'd be a cure worse than the disease.
-			 */
 			if (unlink(path) < 0)
-			{
-				ereport(LOG,
+				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not remove file \"%s\": %m",
 								path)));
-				continue;
-			}
 		}
 	}
 	FreeDir(snap_dir);
-- 
2.35.1

From 4665da8af8af1d0eefeacf3626d3651443323b12 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 10 Aug 2022 07:13:02 +0000
Subject: [PATCH v14] Make more use of get_dirent_type().

We don't need to call stat() or lstat() in several ReadDir() loops, if
d_type is available, as it usually is on most systems.  If not,
get_dirent_type() will do that under the covers.

In a couple of places this will now raise an ERROR if an internal
stat/lstat fails, where previously errors were silently ignored.  ENOENT
was not expected in these locations, because the loop in question is the
one responsible for unlinking files during checkpoint, or runs at
startup.

Author: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220215231123.GA2584239%40nathanxps13
---
 src/backend/access/heap/rewriteheap.c         |  4 +-
 .../replication/logical/reorderbuffer.c       | 12 +++---
 src/backend/replication/logical/snapbuild.c   |  5 +--
 src/backend/replication/slot.c                |  4 +-
 src/backend/storage/file/copydir.c            | 21 +++-------
 src/backend/storage/file/fd.c                 | 20 +++++----
 src/backend/utils/misc/guc-file.l             | 42 +++++++------------
 src/timezone/pgtz.c                           |  8 +---
 8 files changed, 48 insertions(+), 68 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 9dd885d936..a00874f0f7 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, LOG) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 88a37fde72..c37e970de5 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -91,6 +91,7 @@
 #include "access/xact.h"
 #include "access/xlog_internal.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -4407,15 +4408,10 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 {
 	DIR		   *spill_dir;
 	struct dirent *spill_de;
-	struct stat statbuf;
 	char		path[MAXPGPATH * 2 + 12];
 
 	sprintf(path, "pg_replslot/%s", slotname);
 
-	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
-		return;
-
 	spill_dir = AllocateDir(path);
 	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
 	{
@@ -4463,6 +4459,7 @@ StartupReorderBuffer(void)
 {
 	DIR		   *logical_dir;
 	struct dirent *logical_de;
+	char		path[MAXPGPATH * 2 + 12];
 
 	logical_dir = AllocateDir("pg_replslot");
 	while ((logical_de = ReadDir(logical_dir, "pg_replslot")) != NULL)
@@ -4475,6 +4472,11 @@ StartupReorderBuffer(void)
 		if (!ReplicationSlotValidateName(logical_de->d_name, DEBUG2))
 			continue;
 
+		/* we're only handling directories here, skip if it's not one */
+		sprintf(path, "pg_replslot/%s", logical_de->d_name);
+		if (get_dirent_type(path, logical_de, false, LOG) != PGFILETYPE_DIR)
+			continue;
+
 		/*
 		 * ok, has to be a surviving logical slot, iterate and delete
 		 * everything starting with xid-*
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 73c0f15214..5ba185fa0d 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1946,15 +1947,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, LOG) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 850b74936f..dffd87b335 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1442,7 +1443,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1452,7 +1452,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, LOG) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index efb34d4dcb..64764a287d 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2708,6 +2708,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2723,6 +2727,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3159,17 +3167,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index ce5633844c..88460422dd 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1017,7 +1018,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1034,32 +1035,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1067,6 +1045,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.34.1

From a09666d6ca3d3071b16832033b3deec6a04fd75c Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 10 Aug 2022 07:12:15 +0000
Subject: [PATCH v14] Replace lstat() with get_dirent_type() in xlog.c

---
 src/backend/access/transam/xlog.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 34f0150d1e..2b39b6f3a9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -657,8 +657,9 @@ static void PreallocXlogFiles(XLogRecPtr endptr, TimeLineID tli);
 static void RemoveTempXlogFiles(void);
 static void RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr,
 							   XLogRecPtr endptr, TimeLineID insertTLI);
-static void RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-						   XLogSegNo *endlogSegNo, TimeLineID insertTLI);
+static void RemoveXlogFile(const char *segname, const struct dirent *xlde,
+						   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+						   TimeLineID insertTLI);
 static void UpdateLastRemovedPtr(char *filename);
 static void ValidateXLOGDirectoryStructure(void);
 static void CleanupBackupHistory(void);
@@ -3597,7 +3598,7 @@ RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr, XLogRecPtr endptr,
 				/* Update the last removed location in shared memory first */
 				UpdateLastRemovedPtr(xlde->d_name);
 
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endlogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endlogSegNo,
 							   insertTLI);
 			}
 		}
@@ -3670,7 +3671,7 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
 			 * - but seems safer to let them be archived and removed later.
 			 */
 			if (!XLogArchiveIsReady(xlde->d_name))
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endLogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endLogSegNo,
 							   newTLI);
 		}
 	}
@@ -3692,14 +3693,14 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
  * should be used for this timeline.
  */
 static void
-RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-			   XLogSegNo *endlogSegNo, TimeLineID insertTLI)
+RemoveXlogFile(const char *segname, const struct dirent *xlde,
+			   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+			   TimeLineID insertTLI)
 {
 	char		path[MAXPGPATH];
 #ifdef WIN32
 	char		newpath[MAXPGPATH];
 #endif
-	struct stat statbuf;
 
 	snprintf(path, MAXPGPATH, XLOGDIR "/%s", segname);
 
@@ -3711,7 +3712,7 @@ RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
 	if (wal_recycle &&
 		*endlogSegNo <= recycleSegNo &&
 		XLogCtl->InstallXLogFileSegmentActive &&	/* callee rechecks this */
-		lstat(path, &statbuf) == 0 && S_ISREG(statbuf.st_mode) &&
+		get_dirent_type(path, xlde, false, LOG) != PGFILETYPE_REG &&
 		InstallXLogFileSegment(endlogSegNo, path,
 							   true, recycleSegNo, insertTLI))
 	{
-- 
2.34.1

From a6bd634321d9b42714f4e24105fe4662d45844a4 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 10 Aug 2022 09:36:07 +0000
Subject: [PATCH v15] Make more use of get_dirent_type() in place of stat() or
 lstat().

We don't need to call stat() or lstat() in several ReadDir() loops, if
d_type is available, as it usually is on most systems.  If not,
get_dirent_type() will do that under the covers.

Authors: Nathan Bossart <nathandbossart@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220215231123.GA2584239%40nathanxps13
---
 src/backend/access/heap/rewriteheap.c         |  4 +-
 src/backend/access/transam/xlog.c             | 17 ++++----
 .../replication/logical/reorderbuffer.c       | 12 +++---
 src/backend/replication/logical/snapbuild.c   |  5 +--
 src/backend/replication/slot.c                |  4 +-
 src/backend/storage/file/copydir.c            | 21 +++-------
 src/backend/storage/file/fd.c                 | 20 +++++----
 src/backend/utils/misc/guc-file.l             | 42 +++++++------------
 src/timezone/pgtz.c                           |  8 +---
 9 files changed, 57 insertions(+), 76 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 9dd885d936..a00874f0f7 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1227,7 +1227,7 @@ CheckPointLogicalRewriteHeap(void)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, mapping_de, false, LOG) != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 34f0150d1e..073c6f5378 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -657,8 +657,9 @@ static void PreallocXlogFiles(XLogRecPtr endptr, TimeLineID tli);
 static void RemoveTempXlogFiles(void);
 static void RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr,
 							   XLogRecPtr endptr, TimeLineID insertTLI);
-static void RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-						   XLogSegNo *endlogSegNo, TimeLineID insertTLI);
+static void RemoveXlogFile(const char *segname, const struct dirent *xlde,
+						   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+						   TimeLineID insertTLI);
 static void UpdateLastRemovedPtr(char *filename);
 static void ValidateXLOGDirectoryStructure(void);
 static void CleanupBackupHistory(void);
@@ -3597,7 +3598,7 @@ RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr, XLogRecPtr endptr,
 				/* Update the last removed location in shared memory first */
 				UpdateLastRemovedPtr(xlde->d_name);
 
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endlogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endlogSegNo,
 							   insertTLI);
 			}
 		}
@@ -3670,7 +3671,7 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
 			 * - but seems safer to let them be archived and removed later.
 			 */
 			if (!XLogArchiveIsReady(xlde->d_name))
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endLogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endLogSegNo,
 							   newTLI);
 		}
 	}
@@ -3692,14 +3693,14 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
  * should be used for this timeline.
  */
 static void
-RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-			   XLogSegNo *endlogSegNo, TimeLineID insertTLI)
+RemoveXlogFile(const char *segname, const struct dirent *xlde,
+			   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+			   TimeLineID insertTLI)
 {
 	char		path[MAXPGPATH];
 #ifdef WIN32
 	char		newpath[MAXPGPATH];
 #endif
-	struct stat statbuf;
 
 	snprintf(path, MAXPGPATH, XLOGDIR "/%s", segname);
 
@@ -3711,7 +3712,7 @@ RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
 	if (wal_recycle &&
 		*endlogSegNo <= recycleSegNo &&
 		XLogCtl->InstallXLogFileSegmentActive &&	/* callee rechecks this */
-		lstat(path, &statbuf) == 0 && S_ISREG(statbuf.st_mode) &&
+		get_dirent_type(path, xlde, false, LOG) == PGFILETYPE_REG &&
 		InstallXLogFileSegment(endlogSegNo, path,
 							   true, recycleSegNo, insertTLI))
 	{
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 88a37fde72..c37e970de5 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -91,6 +91,7 @@
 #include "access/xact.h"
 #include "access/xlog_internal.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -4407,15 +4408,10 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 {
 	DIR		   *spill_dir;
 	struct dirent *spill_de;
-	struct stat statbuf;
 	char		path[MAXPGPATH * 2 + 12];
 
 	sprintf(path, "pg_replslot/%s", slotname);
 
-	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
-		return;
-
 	spill_dir = AllocateDir(path);
 	while ((spill_de = ReadDirExtended(spill_dir, path, INFO)) != NULL)
 	{
@@ -4463,6 +4459,7 @@ StartupReorderBuffer(void)
 {
 	DIR		   *logical_dir;
 	struct dirent *logical_de;
+	char		path[MAXPGPATH * 2 + 12];
 
 	logical_dir = AllocateDir("pg_replslot");
 	while ((logical_de = ReadDir(logical_dir, "pg_replslot")) != NULL)
@@ -4475,6 +4472,11 @@ StartupReorderBuffer(void)
 		if (!ReplicationSlotValidateName(logical_de->d_name, DEBUG2))
 			continue;
 
+		/* we're only handling directories here, skip if it's not one */
+		sprintf(path, "pg_replslot/%s", logical_de->d_name);
+		if (get_dirent_type(path, logical_de, false, LOG) != PGFILETYPE_DIR)
+			continue;
+
 		/*
 		 * ok, has to be a surviving logical slot, iterate and delete
 		 * everything starting with xid-*
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 73c0f15214..5ba185fa0d 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -1946,15 +1947,13 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
-
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (get_dirent_type(path, snap_de, false, LOG) != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 850b74936f..dffd87b335 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1442,7 +1443,6 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
@@ -1452,7 +1452,7 @@ StartupReplicationSlots(void)
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(path, replication_de, false, LOG) != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index efb34d4dcb..64764a287d 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2708,6 +2708,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2723,6 +2727,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3159,17 +3167,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index ce5633844c..88460422dd 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1017,7 +1018,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1034,32 +1035,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1067,6 +1045,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.34.1

From d5dd101c7c360706fb28f977703ceb1a3aadf201 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Wed, 17 Aug 2022 07:05:01 +0000
Subject: [PATCH v16] Make more use of get_dirent_type() in place of stat() or
 lstat()

We don't need to call stat() or lstat() in several ReadDir() loops, if
d_type is available, as it usually is on most systems.  If not,
get_dirent_type() will do that under the covers.

Authors: Nathan Bossart, Bharath Rupireddy
Reviewed-by: Thomas Munro
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/20220215231123.GA2584239%40nathanxps13
---
 src/backend/access/heap/rewriteheap.c         |  7 +++-
 src/backend/access/transam/xlog.c             | 17 ++++----
 .../replication/logical/reorderbuffer.c       | 28 +++++++++----
 src/backend/replication/logical/snapbuild.c   |  6 ++-
 src/backend/replication/slot.c                |  6 ++-
 src/backend/storage/file/copydir.c            | 21 +++-------
 src/backend/storage/file/fd.c                 | 20 +++++----
 src/backend/utils/misc/guc-file.l             | 42 +++++++------------
 src/timezone/pgtz.c                           |  8 +---
 9 files changed, 78 insertions(+), 77 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 9dd885d936..5b20d1e1d5 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1221,13 +1221,16 @@ CheckPointLogicalRewriteHeap(void)
 		TransactionId create_xid;
 		uint32		hi,
 					lo;
+		PGFileType	de_type;
 
 		if (strcmp(mapping_de->d_name, ".") == 0 ||
 			strcmp(mapping_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		de_type = get_dirent_type(path, mapping_de, false, LOG);
+
+		if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 87b243e0d4..16363a8f84 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -657,8 +657,9 @@ static void PreallocXlogFiles(XLogRecPtr endptr, TimeLineID tli);
 static void RemoveTempXlogFiles(void);
 static void RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr,
 							   XLogRecPtr endptr, TimeLineID insertTLI);
-static void RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-						   XLogSegNo *endlogSegNo, TimeLineID insertTLI);
+static void RemoveXlogFile(const char *segname, const struct dirent *xlde,
+						   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+						   TimeLineID insertTLI);
 static void UpdateLastRemovedPtr(char *filename);
 static void ValidateXLOGDirectoryStructure(void);
 static void CleanupBackupHistory(void);
@@ -3597,7 +3598,7 @@ RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr, XLogRecPtr endptr,
 				/* Update the last removed location in shared memory first */
 				UpdateLastRemovedPtr(xlde->d_name);
 
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endlogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endlogSegNo,
 							   insertTLI);
 			}
 		}
@@ -3670,7 +3671,7 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
 			 * - but seems safer to let them be archived and removed later.
 			 */
 			if (!XLogArchiveIsReady(xlde->d_name))
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endLogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endLogSegNo,
 							   newTLI);
 		}
 	}
@@ -3692,14 +3693,14 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
  * should be used for this timeline.
  */
 static void
-RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-			   XLogSegNo *endlogSegNo, TimeLineID insertTLI)
+RemoveXlogFile(const char *segname, const struct dirent *xlde,
+			   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+			   TimeLineID insertTLI)
 {
 	char		path[MAXPGPATH];
 #ifdef WIN32
 	char		newpath[MAXPGPATH];
 #endif
-	struct stat statbuf;
 
 	snprintf(path, MAXPGPATH, XLOGDIR "/%s", segname);
 
@@ -3711,7 +3712,7 @@ RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
 	if (wal_recycle &&
 		*endlogSegNo <= recycleSegNo &&
 		XLogCtl->InstallXLogFileSegmentActive &&	/* callee rechecks this */
-		lstat(path, &statbuf) == 0 && S_ISREG(statbuf.st_mode) &&
+		get_dirent_type(path, xlde, false, LOG) == PGFILETYPE_REG &&
 		InstallXLogFileSegment(endlogSegNo, path,
 							   true, recycleSegNo, insertTLI))
 	{
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 1c21a1d14b..f61c5b747e 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -91,6 +91,7 @@
 #include "access/xact.h"
 #include "access/xlog_internal.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -254,7 +255,8 @@ static void ReorderBufferRestoreChange(ReorderBuffer *rb, ReorderBufferTXN *txn,
 static void ReorderBufferRestoreCleanup(ReorderBuffer *rb, ReorderBufferTXN *txn);
 static void ReorderBufferTruncateTXN(ReorderBuffer *rb, ReorderBufferTXN *txn,
 									 bool txn_prepared);
-static void ReorderBufferCleanupSerializedTXNs(const char *slotname);
+static void ReorderBufferCleanupSerializedTXNs(const char *slotname,
+											   bool slot_dir_checked);
 static void ReorderBufferSerializedPath(char *path, ReplicationSlot *slot,
 										TransactionId xid, XLogSegNo segno);
 
@@ -375,7 +377,8 @@ ReorderBufferAllocate(void)
 	 * prior exit avoided calling ReorderBufferFree. Failure to do this can
 	 * produce duplicated txns, and it's very cheap if there's nothing there.
 	 */
-	ReorderBufferCleanupSerializedTXNs(NameStr(MyReplicationSlot->data.name));
+	ReorderBufferCleanupSerializedTXNs(NameStr(MyReplicationSlot->data.name),
+									   false);
 
 	return buffer;
 }
@@ -395,7 +398,8 @@ ReorderBufferFree(ReorderBuffer *rb)
 	MemoryContextDelete(context);
 
 	/* Free disk space used by unconsumed reorder buffers */
-	ReorderBufferCleanupSerializedTXNs(NameStr(MyReplicationSlot->data.name));
+	ReorderBufferCleanupSerializedTXNs(NameStr(MyReplicationSlot->data.name),
+									   false);
 }
 
 /*
@@ -4464,7 +4468,7 @@ ReorderBufferRestoreCleanup(ReorderBuffer *rb, ReorderBufferTXN *txn)
  * prior crash or decoding session exit.
  */
 static void
-ReorderBufferCleanupSerializedTXNs(const char *slotname)
+ReorderBufferCleanupSerializedTXNs(const char *slotname, bool slot_dir_checked)
 {
 	DIR		   *spill_dir;
 	struct dirent *spill_de;
@@ -4473,8 +4477,12 @@ ReorderBufferCleanupSerializedTXNs(const char *slotname)
 
 	sprintf(path, "pg_replslot/%s", slotname);
 
-	/* we're only handling directories here, skip if it's not ours */
-	if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+	/*
+	 * We're only handling directories here, skip if it's not ours. Also, skip
+	 * if the caller has already performed this check.
+	 */
+	if (!slot_dir_checked &&
+		lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
 		return;
 
 	spill_dir = AllocateDir(path);
@@ -4524,6 +4532,7 @@ StartupReorderBuffer(void)
 {
 	DIR		   *logical_dir;
 	struct dirent *logical_de;
+	char		path[MAXPGPATH * 2 + 12];
 
 	logical_dir = AllocateDir("pg_replslot");
 	while ((logical_de = ReadDir(logical_dir, "pg_replslot")) != NULL)
@@ -4536,11 +4545,16 @@ StartupReorderBuffer(void)
 		if (!ReplicationSlotValidateName(logical_de->d_name, DEBUG2))
 			continue;
 
+		/* we're only handling directories here, skip if it's not one */
+		sprintf(path, "pg_replslot/%s", logical_de->d_name);
+		if (get_dirent_type(path, logical_de, false, LOG) != PGFILETYPE_DIR)
+			continue;
+
 		/*
 		 * ok, has to be a surviving logical slot, iterate and delete
 		 * everything starting with xid-*
 		 */
-		ReorderBufferCleanupSerializedTXNs(logical_de->d_name);
+		ReorderBufferCleanupSerializedTXNs(logical_de->d_name, true);
 	}
 	FreeDir(logical_dir);
 }
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 1ff2c12240..f90059bb4e 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -2049,15 +2050,16 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
+		PGFileType	de_type;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
+		de_type = get_dirent_type(path, snap_de, false, LOG);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 850b74936f..e9b926d7de 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1442,17 +1443,18 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
+		PGFileType	de_type;
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
 			strcmp(replication_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
+		de_type = get_dirent_type(path, replication_de, false, LOG);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index e3b19ca1ed..bd6f1270f9 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2706,6 +2706,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2721,6 +2725,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3157,17 +3165,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index ce5633844c..88460422dd 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1017,7 +1018,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1034,32 +1035,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1067,6 +1045,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.34.1

From 3ce317e9eb4b37f79e3f822fd1ae53cb5d48b12e Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Sat, 27 Aug 2022 08:29:09 +0000
Subject: [PATCH v17] Make more use of get_dirent_type() in place of stat() or
 lstat()

We don't need to call stat() or lstat() in several ReadDir() loops, if
d_type is available, as it usually is on most systems.  If not,
get_dirent_type() will do that under the covers.

Authors: Nathan Bossart, Bharath Rupireddy
Reviewed-by: Thomas Munro, Andres Freund
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/20220215231123.GA2584239%40nathanxps13
---
 src/backend/access/heap/rewriteheap.c       |  7 +++-
 src/backend/access/transam/xlog.c           | 17 +++++----
 src/backend/replication/logical/snapbuild.c |  6 ++-
 src/backend/replication/slot.c              |  6 ++-
 src/backend/storage/file/copydir.c          | 21 +++--------
 src/backend/storage/file/fd.c               | 20 +++++-----
 src/backend/utils/misc/guc-file.l           | 42 ++++++++-------------
 src/timezone/pgtz.c                         |  8 +---
 8 files changed, 57 insertions(+), 70 deletions(-)

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 9dd885d936..5b20d1e1d5 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -113,6 +113,7 @@
 #include "access/xact.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "common/file_utils.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1213,7 +1214,6 @@ CheckPointLogicalRewriteHeap(void)
 	mappings_dir = AllocateDir("pg_logical/mappings");
 	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
 	{
-		struct stat statbuf;
 		Oid			dboid;
 		Oid			relid;
 		XLogRecPtr	lsn;
@@ -1221,13 +1221,16 @@ CheckPointLogicalRewriteHeap(void)
 		TransactionId create_xid;
 		uint32		hi,
 					lo;
+		PGFileType	de_type;
 
 		if (strcmp(mapping_de->d_name, ".") == 0 ||
 			strcmp(mapping_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		de_type = get_dirent_type(path, mapping_de, false, LOG);
+
+		if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_REG)
 			continue;
 
 		/* Skip over files that cannot be ours. */
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 537845cada..901169946d 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -657,8 +657,9 @@ static void PreallocXlogFiles(XLogRecPtr endptr, TimeLineID tli);
 static void RemoveTempXlogFiles(void);
 static void RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr,
 							   XLogRecPtr endptr, TimeLineID insertTLI);
-static void RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-						   XLogSegNo *endlogSegNo, TimeLineID insertTLI);
+static void RemoveXlogFile(const char *segname, const struct dirent *xlde,
+						   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+						   TimeLineID insertTLI);
 static void UpdateLastRemovedPtr(char *filename);
 static void ValidateXLOGDirectoryStructure(void);
 static void CleanupBackupHistory(void);
@@ -3596,7 +3597,7 @@ RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr lastredoptr, XLogRecPtr endptr,
 				/* Update the last removed location in shared memory first */
 				UpdateLastRemovedPtr(xlde->d_name);
 
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endlogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endlogSegNo,
 							   insertTLI);
 			}
 		}
@@ -3669,7 +3670,7 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
 			 * - but seems safer to let them be archived and removed later.
 			 */
 			if (!XLogArchiveIsReady(xlde->d_name))
-				RemoveXlogFile(xlde->d_name, recycleSegNo, &endLogSegNo,
+				RemoveXlogFile(xlde->d_name, xlde, recycleSegNo, &endLogSegNo,
 							   newTLI);
 		}
 	}
@@ -3691,14 +3692,14 @@ RemoveNonParentXlogFiles(XLogRecPtr switchpoint, TimeLineID newTLI)
  * should be used for this timeline.
  */
 static void
-RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
-			   XLogSegNo *endlogSegNo, TimeLineID insertTLI)
+RemoveXlogFile(const char *segname, const struct dirent *xlde,
+			   XLogSegNo recycleSegNo, XLogSegNo *endlogSegNo,
+			   TimeLineID insertTLI)
 {
 	char		path[MAXPGPATH];
 #ifdef WIN32
 	char		newpath[MAXPGPATH];
 #endif
-	struct stat statbuf;
 
 	snprintf(path, MAXPGPATH, XLOGDIR "/%s", segname);
 
@@ -3710,7 +3711,7 @@ RemoveXlogFile(const char *segname, XLogSegNo recycleSegNo,
 	if (wal_recycle &&
 		*endlogSegNo <= recycleSegNo &&
 		XLogCtl->InstallXLogFileSegmentActive &&	/* callee rechecks this */
-		lstat(path, &statbuf) == 0 && S_ISREG(statbuf.st_mode) &&
+		get_dirent_type(path, xlde, false, LOG) == PGFILETYPE_REG &&
 		InstallXLogFileSegment(endlogSegNo, path,
 							   true, recycleSegNo, insertTLI))
 	{
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index 1ff2c12240..f90059bb4e 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -123,6 +123,7 @@
 #include "access/heapam_xlog.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/logical.h"
@@ -2049,15 +2050,16 @@ CheckPointSnapBuild(void)
 		uint32		hi;
 		uint32		lo;
 		XLogRecPtr	lsn;
-		struct stat statbuf;
+		PGFileType	de_type;
 
 		if (strcmp(snap_de->d_name, ".") == 0 ||
 			strcmp(snap_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_logical/snapshots/%s", snap_de->d_name);
+		de_type = get_dirent_type(path, snap_de, false, LOG);
 
-		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+		if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_REG)
 		{
 			elog(DEBUG1, "only regular files expected: %s", path);
 			continue;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 850b74936f..e9b926d7de 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -41,6 +41,7 @@
 
 #include "access/transam.h"
 #include "access/xlog_internal.h"
+#include "common/file_utils.h"
 #include "common/string.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -1442,17 +1443,18 @@ StartupReplicationSlots(void)
 	replication_dir = AllocateDir("pg_replslot");
 	while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
 	{
-		struct stat statbuf;
 		char		path[MAXPGPATH + 12];
+		PGFileType	de_type;
 
 		if (strcmp(replication_de->d_name, ".") == 0 ||
 			strcmp(replication_de->d_name, "..") == 0)
 			continue;
 
 		snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
+		de_type = get_dirent_type(path, replication_de, false, LOG);
 
 		/* we're only creating directories here, skip if it's not our's */
-		if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
+		if (de_type != PGFILETYPE_ERROR && de_type != PGFILETYPE_DIR)
 			continue;
 
 		/* we crashed while a slot was being setup or deleted, clean up */
diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c
index 658fd95ba9..8a866191e1 100644
--- a/src/backend/storage/file/copydir.c
+++ b/src/backend/storage/file/copydir.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+#include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/copydir.h"
@@ -50,7 +51,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, fromdir)) != NULL)
 	{
-		struct stat fst;
+		PGFileType	xlde_type;
 
 		/* If we got a cancel signal during the copy of the directory, quit */
 		CHECK_FOR_INTERRUPTS();
@@ -62,18 +63,15 @@ copydir(char *fromdir, char *todir, bool recurse)
 		snprintf(fromfile, sizeof(fromfile), "%s/%s", fromdir, xlde->d_name);
 		snprintf(tofile, sizeof(tofile), "%s/%s", todir, xlde->d_name);
 
-		if (lstat(fromfile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", fromfile)));
+		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
 
-		if (S_ISDIR(fst.st_mode))
+		if (xlde_type == PGFILETYPE_DIR)
 		{
 			/* recurse to handle subdirectories */
 			if (recurse)
 				copydir(fromfile, tofile, true);
 		}
-		else if (S_ISREG(fst.st_mode))
+		else if (xlde_type == PGFILETYPE_REG)
 			copy_file(fromfile, tofile);
 	}
 	FreeDir(xldir);
@@ -89,8 +87,6 @@ copydir(char *fromdir, char *todir, bool recurse)
 
 	while ((xlde = ReadDir(xldir, todir)) != NULL)
 	{
-		struct stat fst;
-
 		if (strcmp(xlde->d_name, ".") == 0 ||
 			strcmp(xlde->d_name, "..") == 0)
 			continue;
@@ -101,12 +97,7 @@ copydir(char *fromdir, char *todir, bool recurse)
 		 * We don't need to sync subdirectories here since the recursive
 		 * copydir will do it before it returns
 		 */
-		if (lstat(tofile, &fst) < 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m", tofile)));
-
-		if (S_ISREG(fst.st_mode))
+		if (get_dirent_type(tofile, xlde, false, ERROR) == PGFILETYPE_REG)
 			fsync_fname(tofile, false);
 	}
 	FreeDir(xldir);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index e3b19ca1ed..bd6f1270f9 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -2706,6 +2706,10 @@ TryAgain:
  *
  * The pathname passed to AllocateDir must be passed to this routine too,
  * but it is only used for error reporting.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDir(DIR *dir, const char *dirname)
@@ -2721,6 +2725,10 @@ ReadDir(DIR *dir, const char *dirname)
  * If elevel < ERROR, returns NULL after any error.  With the normal coding
  * pattern, this will result in falling out of the loop immediately as
  * though the directory contained no (more) entries.
+ *
+ * If you need to discover the file type of an entry, consider using
+ * get_dirent_type() (instead of stat()/lstat()) to avoid extra system calls on
+ * many platforms.
  */
 struct dirent *
 ReadDirExtended(DIR *dir, const char *dirname, int elevel)
@@ -3157,17 +3165,11 @@ RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok, bool unlink_all)
 					PG_TEMP_FILE_PREFIX,
 					strlen(PG_TEMP_FILE_PREFIX)) == 0)
 		{
-			struct stat statbuf;
+			PGFileType	type = get_dirent_type(rm_path, temp_de, false, LOG);
 
-			if (lstat(rm_path, &statbuf) < 0)
-			{
-				ereport(LOG,
-						(errcode_for_file_access(),
-						 errmsg("could not stat file \"%s\": %m", rm_path)));
+			if (type == PGFILETYPE_ERROR)
 				continue;
-			}
-
-			if (S_ISDIR(statbuf.st_mode))
+			else if (type == PGFILETYPE_DIR)
 			{
 				/* recursively remove contents, then directory itself */
 				RemovePgTempFilesInDir(rm_path, false, true);
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index ce5633844c..88460422dd 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -14,6 +14,7 @@
 #include <ctype.h>
 #include <unistd.h>
 
+#include "common/file_utils.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
@@ -1017,7 +1018,7 @@ ParseConfigDirectory(const char *includedir,
 
 	while ((de = ReadDir(d, directory)) != NULL)
 	{
-		struct stat st;
+		PGFileType	de_type;
 		char		filename[MAXPGPATH];
 
 		/*
@@ -1034,32 +1035,9 @@ ParseConfigDirectory(const char *includedir,
 
 		join_path_components(filename, directory, de->d_name);
 		canonicalize_path(filename);
-		if (stat(filename, &st) == 0)
+		de_type = get_dirent_type(filename, de, true, elevel);
+		if (de_type == PGFILETYPE_ERROR)
 		{
-			if (!S_ISDIR(st.st_mode))
-			{
-				/* Add file to array, increasing its size in blocks of 32 */
-				if (num_filenames >= size_filenames)
-				{
-					size_filenames += 32;
-					filenames = (char **) repalloc(filenames,
-											size_filenames * sizeof(char *));
-				}
-				filenames[num_filenames] = pstrdup(filename);
-				num_filenames++;
-			}
-		}
-		else
-		{
-			/*
-			 * stat does not care about permissions, so the most likely reason
-			 * a file can't be accessed now is if it was removed between the
-			 * directory listing and now.
-			 */
-			ereport(elevel,
-					(errcode_for_file_access(),
-					 errmsg("could not stat file \"%s\": %m",
-							filename)));
 			record_config_file_error(psprintf("could not stat file \"%s\"",
 											  filename),
 									 calling_file, calling_lineno,
@@ -1067,6 +1045,18 @@ ParseConfigDirectory(const char *includedir,
 			status = false;
 			goto cleanup;
 		}
+		else if (de_type != PGFILETYPE_DIR)
+		{
+			/* Add file to array, increasing its size in blocks of 32 */
+			if (num_filenames >= size_filenames)
+			{
+				size_filenames += 32;
+				filenames = (char **) repalloc(filenames,
+											   size_filenames * sizeof(char *));
+			}
+			filenames[num_filenames] = pstrdup(filename);
+			num_filenames++;
+		}
 	}
 
 	if (num_filenames > 0)
diff --git a/src/timezone/pgtz.c b/src/timezone/pgtz.c
index 3c278dd0f3..72f9e3d5e6 100644
--- a/src/timezone/pgtz.c
+++ b/src/timezone/pgtz.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "common/file_utils.h"
 #include "datatype/timestamp.h"
 #include "miscadmin.h"
 #include "pgtz.h"
@@ -429,7 +430,6 @@ pg_tzenumerate_next(pg_tzenum *dir)
 	{
 		struct dirent *direntry;
 		char		fullname[MAXPGPATH * 2];
-		struct stat statbuf;
 
 		direntry = ReadDir(dir->dirdesc[dir->depth], dir->dirname[dir->depth]);
 
@@ -447,12 +447,8 @@ pg_tzenumerate_next(pg_tzenum *dir)
 
 		snprintf(fullname, sizeof(fullname), "%s/%s",
 				 dir->dirname[dir->depth], direntry->d_name);
-		if (stat(fullname, &statbuf) != 0)
-			ereport(ERROR,
-					(errcode_for_file_access(),
-					 errmsg("could not stat \"%s\": %m", fullname)));
 
-		if (S_ISDIR(statbuf.st_mode))
+		if (get_dirent_type(fullname, direntry, true, ERROR) == PGFILETYPE_DIR)
 		{
 			/* Step into the subdirectory */
 			if (dir->depth >= MAX_TZDIR_DEPTH - 1)
-- 
2.34.1