4 files changed, 39 insertions, 2 deletions

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index 8d3c861a330..ed7ba181c79 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -1168,9 +1168,14 @@ heap_xlog_logical_rewrite(XLogReaderState *r)
 	/* write out tail end of mapping file (again) */
 	pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE);
 	if (write(fd, data, len) != len)
+	{
+		/* if write didn't set errno, assume problem is no disk space */
+		if (errno == 0)
+			errno = ENOSPC;
 		ereport(ERROR,
 				(errcode_for_file_access(),
 				 errmsg("could not write to file \"%s\": %m", path)));
+	}
 	pgstat_report_wait_end();
 
 	/*
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 65194db70e3..a9ef1b3d73c 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -1241,12 +1241,17 @@ ReadTwoPhaseFile(TransactionId xid, bool give_warnings)
 	 */
 	if (fstat(fd, &stat))
 	{
+		int			save_errno = errno;
+
 		CloseTransientFile(fd);
 		if (give_warnings)
+		{
+			errno = save_errno;
 			ereport(WARNING,
 					(errcode_for_file_access(),
 					 errmsg("could not stat two-phase state file \"%s\": %m",
 							path)));
+		}
 		return NULL;
 	}
 
@@ -1274,13 +1279,18 @@ ReadTwoPhaseFile(TransactionId xid, bool give_warnings)
 	pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_READ);
 	if (read(fd, buf, stat.st_size) != stat.st_size)
 	{
+		int			save_errno = errno;
+
 		pgstat_report_wait_end();
 		CloseTransientFile(fd);
 		if (give_warnings)
+		{
+			errno = save_errno;
 			ereport(WARNING,
 					(errcode_for_file_access(),
 					 errmsg("could not read two-phase state file \"%s\": %m",
 							path)));
+		}
 		pfree(buf);
 		return NULL;
 	}
@@ -1663,16 +1673,26 @@ RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
 	pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_WRITE);
 	if (write(fd, content, len) != len)
 	{
+		int			save_errno = errno;
+
 		pgstat_report_wait_end();
 		CloseTransientFile(fd);
+
+		/* if write didn't set errno, assume problem is no disk space */
+		errno = save_errno ? save_errno : ENOSPC;
 		ereport(ERROR,
 				(errcode_for_file_access(),
 				 errmsg("could not write two-phase state file: %m")));
 	}
 	if (write(fd, &statefile_crc, sizeof(pg_crc32c)) != sizeof(pg_crc32c))
 	{
+		int			save_errno = errno;
+
 		pgstat_report_wait_end();
 		CloseTransientFile(fd);
+
+		/* if write didn't set errno, assume problem is no disk space */
+		errno = save_errno ? save_errno : ENOSPC;
 		ereport(ERROR,
 				(errcode_for_file_access(),
 				 errmsg("could not write two-phase state file: %m")));
@@ -1686,7 +1706,10 @@ RecreateTwoPhaseFile(TransactionId xid, void *content, int len)
 	pgstat_report_wait_start(WAIT_EVENT_TWOPHASE_FILE_SYNC);
 	if (pg_fsync(fd) != 0)
 	{
+		int			save_errno = errno;
+
 		CloseTransientFile(fd);
+		errno = save_errno;
 		ereport(ERROR,
 				(errcode_for_file_access(),
 				 errmsg("could not fsync two-phase state file: %m")));
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index adbd6a21264..1a419aa49bf 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -3268,7 +3268,10 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
 	pgstat_report_wait_start(WAIT_EVENT_WAL_INIT_SYNC);
 	if (pg_fsync(fd) != 0)
 	{
+		int			save_errno = errno;
+
 		close(fd);
+		errno = save_errno;
 		ereport(ERROR,
 				(errcode_for_file_access(),
 				 errmsg("could not fsync file \"%s\": %m", tmppath)));
@@ -11675,8 +11678,10 @@ retry:
 	if (lseek(readFile, (off_t) readOff, SEEK_SET) < 0)
 	{
 		char		fname[MAXFNAMELEN];
+		int			save_errno = errno;
 
 		XLogFileName(fname, curFileTLI, readSegNo, wal_segment_size);
+		errno = save_errno;
 		ereport(emode_for_corrupt_record(emode, targetPagePtr + reqLen),
 				(errcode_for_file_access(),
 				 errmsg("could not seek in log segment %s to offset %u: %m",
@@ -11688,9 +11693,11 @@ retry:
 	if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 	{
 		char		fname[MAXFNAMELEN];
+		int			save_errno = errno;
 
 		pgstat_report_wait_end();
 		XLogFileName(fname, curFileTLI, readSegNo, wal_segment_size);
+		errno = save_errno;
 		ereport(emode_for_corrupt_record(emode, targetPagePtr + reqLen),
 				(errcode_for_file_access(),
 				 errmsg("could not read from log segment %s, offset %u: %m",
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 52fe55e2afb..4ecdc9220f0 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -718,9 +718,10 @@ XLogRead(char *buf, int segsize, TimeLineID tli, XLogRecPtr startptr,
 			if (lseek(sendFile, (off_t) startoff, SEEK_SET) < 0)
 			{
 				char		path[MAXPGPATH];
+				int			save_errno = errno;
 
 				XLogFilePath(path, tli, sendSegNo, segsize);
-
+				errno = save_errno;
 				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not seek in log segment %s to offset %u: %m",
@@ -741,9 +742,10 @@ XLogRead(char *buf, int segsize, TimeLineID tli, XLogRecPtr startptr,
 		if (readbytes <= 0)
 		{
 			char		path[MAXPGPATH];
+			int			save_errno = errno;
 
 			XLogFilePath(path, tli, sendSegNo, segsize);
-
+			errno = save_errno;
 			ereport(ERROR,
 					(errcode_for_file_access(),
 					 errmsg("could not read from log segment %s, offset %u, length %lu: %m",