diff --git a/src/bin/pg_dump/compress_gzip.c b/src/bin/pg_dump/compress_gzip.c
index 63dfd9668c1..f76dd42219b 100644
--- a/src/bin/pg_dump/compress_gzip.c
+++ b/src/bin/pg_dump/compress_gzip.c
@@ -251,34 +251,49 @@ InitCompressorGzip(CompressorState *cs,
  *----------------------
  */
 
-static bool
-Gzip_read(void *ptr, size_t size, size_t *rsize, CompressFileHandle *CFH)
+static size_t
+Gzip_read(void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	gzFile		gzfp = (gzFile) CFH->private_data;
 	int			gzret;
 
 	gzret = gzread(gzfp, ptr, size);
-	if (gzret <= 0 && !gzeof(gzfp))
+
+	/*
+	 * gzread returns zero on EOF as well as some error conditions, and less
+	 * than zero on other error conditions, so we need to inspect for EOF on
+	 * zero.
+	 */
+	if (gzret <= 0)
 	{
 		int			errnum;
-		const char *errmsg = gzerror(gzfp, &errnum);
+		const char *errmsg;
+
+		if (gzret == 0 && gzeof(gzfp))
+			return 0;
+
+		errmsg = gzerror(gzfp, &errnum);
 
 		pg_fatal("could not read from input file: %s",
 				 errnum == Z_ERRNO ? strerror(errno) : errmsg);
 	}
 
-	if (rsize)
-		*rsize = (size_t) gzret;
-
-	return true;
+	return (size_t) gzret;
 }
 
-static bool
+static void
 Gzip_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	gzFile		gzfp = (gzFile) CFH->private_data;
+	int			errnum;
+	const char *errmsg;
 
-	return gzwrite(gzfp, ptr, size) > 0;
+	if (gzwrite(gzfp, ptr, size) != size)
+	{
+		errmsg = gzerror(gzfp, &errnum);
+		pg_fatal("could not write to file: %s",
+				 errnum == Z_ERRNO ? strerror(errno) : errmsg);
+	}
 }
 
 static int
diff --git a/src/bin/pg_dump/compress_io.c b/src/bin/pg_dump/compress_io.c
index efedc53a173..ec8148cabfa 100644
--- a/src/bin/pg_dump/compress_io.c
+++ b/src/bin/pg_dump/compress_io.c
@@ -270,6 +270,7 @@ InitDiscoverCompressFileHandle(const char *path, const char *mode)
 	}
 
 	CFH = InitCompressFileHandle(compression_spec);
+	errno = 0;
 	if (!CFH->open_func(fname, -1, mode, CFH))
 	{
 		free_keep_errno(CFH);
@@ -290,6 +291,7 @@ EndCompressFileHandle(CompressFileHandle *CFH)
 {
 	bool		ret = false;
 
+	errno = 0;
 	if (CFH->private_data)
 		ret = CFH->close_func(CFH);
 
diff --git a/src/bin/pg_dump/compress_io.h b/src/bin/pg_dump/compress_io.h
index 621e03a5c85..63c8ff909f4 100644
--- a/src/bin/pg_dump/compress_io.h
+++ b/src/bin/pg_dump/compress_io.h
@@ -123,21 +123,22 @@ struct CompressFileHandle
 									CompressFileHandle *CFH);
 
 	/*
-	 * Read 'size' bytes of data from the file and store them into 'ptr'.
-	 * Optionally it will store the number of bytes read in 'rsize'.
+	 * Read up to 'size' bytes of data from the file and store them into
+	 * 'ptr'.
 	 *
-	 * Returns true on success and throws an internal error otherwise.
+	 * Returns number of bytes read (this might be less than 'size' if EOF was
+	 * reached).  Exits via pg_fatal for all error conditions.
 	 */
-	bool		(*read_func) (void *ptr, size_t size, size_t *rsize,
+	size_t		(*read_func) (void *ptr, size_t size,
 							  CompressFileHandle *CFH);
 
 	/*
 	 * Write 'size' bytes of data into the file from 'ptr'.
 	 *
-	 * Returns true on success and false on error.
+	 * Returns nothing, exits via pg_fatal for all error conditions.
 	 */
-	bool		(*write_func) (const void *ptr, size_t size,
-							   struct CompressFileHandle *CFH);
+	void		(*write_func) (const void *ptr, size_t size,
+							   CompressFileHandle *CFH);
 
 	/*
 	 * Read at most size - 1 characters from the compress file handle into
diff --git a/src/bin/pg_dump/compress_lz4.c b/src/bin/pg_dump/compress_lz4.c
index 52214b31eea..3c4418a4873 100644
--- a/src/bin/pg_dump/compress_lz4.c
+++ b/src/bin/pg_dump/compress_lz4.c
@@ -12,6 +12,8 @@
  *-------------------------------------------------------------------------
  */
 #include "postgres_fe.h"
+#include <unistd.h>
+
 #include "pg_backup_utils.h"
 
 #include "compress_lz4.h"
@@ -358,7 +360,6 @@ LZ4Stream_init(LZ4State *state, int size, bool compressing)
 		return true;
 
 	state->compressing = compressing;
-	state->inited = true;
 
 	/* When compressing, write LZ4 header to the output stream. */
 	if (state->compressing)
@@ -367,6 +368,7 @@ LZ4Stream_init(LZ4State *state, int size, bool compressing)
 		if (!LZ4State_compression_init(state))
 			return false;
 
+		errno = 0;
 		if (fwrite(state->buffer, 1, state->compressedlen, state->fp) != state->compressedlen)
 		{
 			errno = (errno) ? errno : ENOSPC;
@@ -390,6 +392,7 @@ LZ4Stream_init(LZ4State *state, int size, bool compressing)
 		state->overflowlen = 0;
 	}
 
+	state->inited = true;
 	return true;
 }
 
@@ -457,7 +460,11 @@ LZ4Stream_read_internal(LZ4State *state, void *ptr, int ptrsize, bool eol_flag)
 
 	/* Lazy init */
 	if (!LZ4Stream_init(state, size, false /* decompressing */ ))
+	{
+		pg_log_error("unable to initialize LZ4 library: %s",
+					 LZ4F_getErrorName(state->errcode));
 		return -1;
+	}
 
 	/* No work needs to be done for a zero-sized output buffer */
 	if (size <= 0)
@@ -484,7 +491,10 @@ LZ4Stream_read_internal(LZ4State *state, void *ptr, int ptrsize, bool eol_flag)
 
 		rsize = fread(readbuf, 1, size, state->fp);
 		if (rsize < size && !feof(state->fp))
+		{
+			pg_log_error("could not read from input file: %m");
 			return -1;
+		}
 
 		rp = (char *) readbuf;
 		rend = (char *) readbuf + rsize;
@@ -501,6 +511,8 @@ LZ4Stream_read_internal(LZ4State *state, void *ptr, int ptrsize, bool eol_flag)
 			if (LZ4F_isError(status))
 			{
 				state->errcode = status;
+				pg_log_error("could not read from input file: %s",
+							 LZ4F_getErrorName(state->errcode));
 				return -1;
 			}
 
@@ -558,7 +570,7 @@ LZ4Stream_read_internal(LZ4State *state, void *ptr, int ptrsize, bool eol_flag)
 /*
  * Compress size bytes from ptr and write them to the stream.
  */
-static bool
+static void
 LZ4Stream_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	LZ4State   *state = (LZ4State *) CFH->private_data;
@@ -567,7 +579,8 @@ LZ4Stream_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 
 	/* Lazy init */
 	if (!LZ4Stream_init(state, size, true))
-		return false;
+		pg_fatal("unable to initialize LZ4 library: %s",
+				 LZ4F_getErrorName(state->errcode));
 
 	while (remaining > 0)
 	{
@@ -578,28 +591,24 @@ LZ4Stream_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 		status = LZ4F_compressUpdate(state->ctx, state->buffer, state->buflen,
 									 ptr, chunk, NULL);
 		if (LZ4F_isError(status))
-		{
-			state->errcode = status;
-			return false;
-		}
+			pg_fatal("error during writing: %s", LZ4F_getErrorName(status));
 
+		errno = 0;
 		if (fwrite(state->buffer, 1, status, state->fp) != status)
 		{
 			errno = (errno) ? errno : ENOSPC;
-			return false;
+			pg_fatal("error during writing: %m");
 		}
 
 		ptr = ((const char *) ptr) + chunk;
 	}
-
-	return true;
 }
 
 /*
  * fread() equivalent implementation for LZ4 compressed files.
  */
-static bool
-LZ4Stream_read(void *ptr, size_t size, size_t *rsize, CompressFileHandle *CFH)
+static size_t
+LZ4Stream_read(void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	LZ4State   *state = (LZ4State *) CFH->private_data;
 	int			ret;
@@ -607,10 +616,7 @@ LZ4Stream_read(void *ptr, size_t size, size_t *rsize, CompressFileHandle *CFH)
 	if ((ret = LZ4Stream_read_internal(state, ptr, size, false)) < 0)
 		pg_fatal("could not read from input file: %s", LZ4Stream_get_error(CFH));
 
-	if (rsize)
-		*rsize = (size_t) ret;
-
-	return true;
+	return (size_t) ret;
 }
 
 /*
@@ -643,11 +649,13 @@ LZ4Stream_gets(char *ptr, int size, CompressFileHandle *CFH)
 	int			ret;
 
 	ret = LZ4Stream_read_internal(state, ptr, size - 1, true);
-	if (ret < 0 || (ret == 0 && !LZ4Stream_eof(CFH)))
-		pg_fatal("could not read from input file: %s", LZ4Stream_get_error(CFH));
 
-	/* Done reading */
-	if (ret == 0)
+	/*
+	 * LZ4Stream_read_internal returning 0 or -1 means that it was either an
+	 * EOF or an error, but gets_func is defined to return NULL in either case
+	 * so we can treat both the same here.
+	 */
+	if (ret <= 0)
 		return NULL;
 
 	/*
@@ -669,6 +677,7 @@ LZ4Stream_close(CompressFileHandle *CFH)
 	FILE	   *fp;
 	LZ4State   *state = (LZ4State *) CFH->private_data;
 	size_t		status;
+	int			ret;
 
 	fp = state->fp;
 	if (state->inited)
@@ -677,25 +686,31 @@ LZ4Stream_close(CompressFileHandle *CFH)
 		{
 			status = LZ4F_compressEnd(state->ctx, state->buffer, state->buflen, NULL);
 			if (LZ4F_isError(status))
-				pg_fatal("could not end compression: %s",
-						 LZ4F_getErrorName(status));
-			else if (fwrite(state->buffer, 1, status, state->fp) != status)
 			{
-				errno = (errno) ? errno : ENOSPC;
-				WRITE_ERROR_EXIT;
+				pg_log_error("could not end compression: %s",
+							 LZ4F_getErrorName(status));
+			}
+			else
+			{
+				errno = 0;
+				if (fwrite(state->buffer, 1, status, state->fp) != status)
+				{
+					errno = (errno) ? errno : ENOSPC;
+					pg_log_error("could not write to output file: %m");
+				}
 			}
 
 			status = LZ4F_freeCompressionContext(state->ctx);
 			if (LZ4F_isError(status))
-				pg_fatal("could not end compression: %s",
-						 LZ4F_getErrorName(status));
+				pg_log_error("could not end compression: %s",
+							 LZ4F_getErrorName(status));
 		}
 		else
 		{
 			status = LZ4F_freeDecompressionContext(state->dtx);
 			if (LZ4F_isError(status))
-				pg_fatal("could not end decompression: %s",
-						 LZ4F_getErrorName(status));
+				pg_log_error("could not end decompression: %s",
+							 LZ4F_getErrorName(status));
 			pg_free(state->overflowbuf);
 		}
 
@@ -703,29 +718,35 @@ LZ4Stream_close(CompressFileHandle *CFH)
 	}
 
 	pg_free(state);
+	CFH->private_data = NULL;
 
-	return fclose(fp) == 0;
+	errno = 0;
+	ret = fclose(fp);
+	if (ret != 0)
+	{
+		pg_log_error("could not close file: %m");
+		return false;
+	}
+
+	return true;
 }
 
 static bool
 LZ4Stream_open(const char *path, int fd, const char *mode,
 			   CompressFileHandle *CFH)
 {
-	FILE	   *fp;
 	LZ4State   *state = (LZ4State *) CFH->private_data;
 
 	if (fd >= 0)
-		fp = fdopen(fd, mode);
+		state->fp = fdopen(dup(fd), mode);
 	else
-		fp = fopen(path, mode);
-	if (fp == NULL)
+		state->fp = fopen(path, mode);
+	if (state->fp == NULL)
 	{
 		state->errcode = errno;
 		return false;
 	}
 
-	state->fp = fp;
-
 	return true;
 }
 
diff --git a/src/bin/pg_dump/compress_none.c b/src/bin/pg_dump/compress_none.c
index 736a7957bc7..9effc7e4fe2 100644
--- a/src/bin/pg_dump/compress_none.c
+++ b/src/bin/pg_dump/compress_none.c
@@ -83,36 +83,32 @@ InitCompressorNone(CompressorState *cs,
  * Private routines
  */
 
-static bool
-read_none(void *ptr, size_t size, size_t *rsize, CompressFileHandle *CFH)
+static size_t
+read_none(void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	FILE	   *fp = (FILE *) CFH->private_data;
 	size_t		ret;
 
-	if (size == 0)
-		return true;
-
 	ret = fread(ptr, 1, size, fp);
-	if (ret != size && !feof(fp))
+	if (ferror(fp))
 		pg_fatal("could not read from input file: %s",
 				 strerror(errno));
 
-	if (rsize)
-		*rsize = ret;
-
-	return true;
+	return ret;
 }
 
-static bool
+static void
 write_none(const void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	size_t		ret;
 
+	errno = 0;
 	ret = fwrite(ptr, 1, size, (FILE *) CFH->private_data);
 	if (ret != size)
-		return false;
-
-	return true;
+	{
+		errno = (errno) ? errno : ENOSPC;
+		pg_fatal("could not write to file: %m");
+	}
 }
 
 static const char *
@@ -154,7 +150,12 @@ close_none(CompressFileHandle *CFH)
 	CFH->private_data = NULL;
 
 	if (fp)
+	{
+		errno = 0;
 		ret = fclose(fp);
+		if (ret != 0)
+			pg_log_error("could not close file: %m");
+	}
 
 	return ret == 0;
 }
diff --git a/src/bin/pg_dump/compress_zstd.c b/src/bin/pg_dump/compress_zstd.c
index 078be03387e..13d5a55a3ef 100644
--- a/src/bin/pg_dump/compress_zstd.c
+++ b/src/bin/pg_dump/compress_zstd.c
@@ -13,6 +13,7 @@
  */
 
 #include "postgres_fe.h"
+#include <unistd.h>
 
 #include "pg_backup_utils.h"
 #include "compress_zstd.h"
@@ -257,8 +258,8 @@ InitCompressorZstd(CompressorState *cs,
  * Compressed stream API
  */
 
-static bool
-Zstd_read(void *ptr, size_t size, size_t *rdsize, CompressFileHandle *CFH)
+static size_t
+Zstd_read_internal(void *ptr, size_t size, CompressFileHandle *CFH, bool exit_on_error)
 {
 	ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
 	ZSTD_inBuffer *input = &zstdcs->input;
@@ -267,6 +268,22 @@ Zstd_read(void *ptr, size_t size, size_t *rdsize, CompressFileHandle *CFH)
 	size_t		res,
 				cnt;
 
+	/*
+	 * If this is the first call to the reading function, initialize the
+	 * required datastructures.
+	 */
+	if (zstdcs->dstream == NULL)
+	{
+		zstdcs->input.src = pg_malloc0(input_allocated_size);
+		zstdcs->dstream = ZSTD_createDStream();
+		if (zstdcs->dstream == NULL)
+		{
+			if (exit_on_error)
+				pg_fatal("could not initialize compression library");
+			return -1;
+		}
+	}
+
 	output->size = size;
 	output->dst = ptr;
 	output->pos = 0;
@@ -291,6 +308,13 @@ Zstd_read(void *ptr, size_t size, size_t *rdsize, CompressFileHandle *CFH)
 		if (input->pos == input->size)
 		{
 			cnt = fread(unconstify(void *, input->src), 1, input_allocated_size, zstdcs->fp);
+			if (ferror(zstdcs->fp))
+			{
+				if (exit_on_error)
+					pg_fatal("could not read from input file: %m");
+				return -1;
+			}
+
 			input->size = cnt;
 
 			Assert(cnt <= input_allocated_size);
@@ -306,7 +330,11 @@ Zstd_read(void *ptr, size_t size, size_t *rdsize, CompressFileHandle *CFH)
 			res = ZSTD_decompressStream(zstdcs->dstream, output, input);
 
 			if (ZSTD_isError(res))
-				pg_fatal("could not decompress data: %s", ZSTD_getErrorName(res));
+			{
+				if (exit_on_error)
+					pg_fatal("could not decompress data: %s", ZSTD_getErrorName(res));
+				return -1;
+			}
 
 			if (output->pos == output->size)
 				break;			/* No more room for output */
@@ -319,13 +347,10 @@ Zstd_read(void *ptr, size_t size, size_t *rdsize, CompressFileHandle *CFH)
 			break;				/* We read all the data that fits */
 	}
 
-	if (rdsize != NULL)
-		*rdsize = output->pos;
-
-	return true;
+	return output->pos;
 }
 
-static bool
+static void
 Zstd_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 {
 	ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
@@ -338,41 +363,40 @@ Zstd_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 	input->size = size;
 	input->pos = 0;
 
+	if (zstdcs->cstream == NULL)
+	{
+		zstdcs->output.size = ZSTD_CStreamOutSize();
+		zstdcs->output.dst = pg_malloc0(zstdcs->output.size);
+		zstdcs->cstream = _ZstdCStreamParams(CFH->compression_spec);
+		if (zstdcs->cstream == NULL)
+			pg_fatal("could not initialize compression library");
+	}
+
 	/* Consume all input, to be flushed later */
 	while (input->pos != input->size)
 	{
 		output->pos = 0;
 		res = ZSTD_compressStream2(zstdcs->cstream, output, input, ZSTD_e_continue);
 		if (ZSTD_isError(res))
-		{
-			zstdcs->zstderror = ZSTD_getErrorName(res);
-			return false;
-		}
+			pg_fatal("could not write to file: %s", ZSTD_getErrorName(res));
 
+		errno = 0;
 		cnt = fwrite(output->dst, 1, output->pos, zstdcs->fp);
 		if (cnt != output->pos)
 		{
-			zstdcs->zstderror = strerror(errno);
-			return false;
+			errno = (errno) ? errno : ENOSPC;
+			pg_fatal("could not write to file: %m");
 		}
 	}
-
-	return size;
 }
 
 static int
 Zstd_getc(CompressFileHandle *CFH)
 {
-	ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
-	int			ret;
+	unsigned char ret;
 
-	if (CFH->read_func(&ret, 1, NULL, CFH) != 1)
-	{
-		if (feof(zstdcs->fp))
-			pg_fatal("could not read from input file: end of file");
-		else
-			pg_fatal("could not read from input file: %m");
-	}
+	if (CFH->read_func(&ret, 1, CFH) != 1)
+		pg_fatal("could not read from input file: end of file");
 	return ret;
 }
 
@@ -389,11 +413,7 @@ Zstd_gets(char *buf, int len, CompressFileHandle *CFH)
 	 */
 	for (i = 0; i < len - 1; ++i)
 	{
-		size_t		readsz;
-
-		if (!CFH->read_func(&buf[i], 1, &readsz, CFH))
-			break;
-		if (readsz != 1)
+		if (Zstd_read_internal(&buf[i], 1, CFH, false) != 1)
 			break;
 		if (buf[i] == '\n')
 		{
@@ -405,10 +425,17 @@ Zstd_gets(char *buf, int len, CompressFileHandle *CFH)
 	return i > 0 ? buf : NULL;
 }
 
+static size_t
+Zstd_read(void *ptr, size_t size, CompressFileHandle *CFH)
+{
+	return Zstd_read_internal(ptr, size, CFH, true);
+}
+
 static bool
 Zstd_close(CompressFileHandle *CFH)
 {
 	ZstdCompressorState *zstdcs = (ZstdCompressorState *) CFH->private_data;
+	bool		success = true;
 
 	if (zstdcs->cstream)
 	{
@@ -425,14 +452,18 @@ Zstd_close(CompressFileHandle *CFH)
 			if (ZSTD_isError(res))
 			{
 				zstdcs->zstderror = ZSTD_getErrorName(res);
-				return false;
+				success = false;
+				break;
 			}
 
+			errno = 0;
 			cnt = fwrite(output->dst, 1, output->pos, zstdcs->fp);
 			if (cnt != output->pos)
 			{
+				errno = (errno) ? errno : ENOSPC;
 				zstdcs->zstderror = strerror(errno);
-				return false;
+				success = false;
+				break;
 			}
 
 			if (res == 0)
@@ -449,11 +480,16 @@ Zstd_close(CompressFileHandle *CFH)
 		pg_free(unconstify(void *, zstdcs->input.src));
 	}
 
+	errno = 0;
 	if (fclose(zstdcs->fp) != 0)
-		return false;
+	{
+		zstdcs->zstderror = strerror(errno);
+		success = false;
+	}
 
 	pg_free(zstdcs);
-	return true;
+	CFH->private_data = NULL;
+	return success;
 }
 
 static bool
@@ -471,35 +507,33 @@ Zstd_open(const char *path, int fd, const char *mode,
 	FILE	   *fp;
 	ZstdCompressorState *zstdcs;
 
+	/*
+	 * Clear state storage to avoid having the fd point to non-NULL memory on
+	 * error return.
+	 */
+	CFH->private_data = NULL;
+
+	zstdcs = (ZstdCompressorState *) pg_malloc_extended(sizeof(*zstdcs),
+														MCXT_ALLOC_NO_OOM | MCXT_ALLOC_ZERO);
+	if (!zstdcs)
+	{
+		errno = ENOMEM;
+		return false;
+	}
+
 	if (fd >= 0)
-		fp = fdopen(fd, mode);
+		fp = fdopen(dup(fd), mode);
 	else
 		fp = fopen(path, mode);
 
 	if (fp == NULL)
+	{
+		pg_free(zstdcs);
 		return false;
+	}
 
-	zstdcs = (ZstdCompressorState *) pg_malloc0(sizeof(*zstdcs));
-	CFH->private_data = zstdcs;
 	zstdcs->fp = fp;
-
-	if (mode[0] == 'r')
-	{
-		zstdcs->input.src = pg_malloc0(ZSTD_DStreamInSize());
-		zstdcs->dstream = ZSTD_createDStream();
-		if (zstdcs->dstream == NULL)
-			pg_fatal("could not initialize compression library");
-	}
-	else if (mode[0] == 'w' || mode[0] == 'a')
-	{
-		zstdcs->output.size = ZSTD_CStreamOutSize();
-		zstdcs->output.dst = pg_malloc0(zstdcs->output.size);
-		zstdcs->cstream = _ZstdCStreamParams(CFH->compression_spec);
-		if (zstdcs->cstream == NULL)
-			pg_fatal("could not initialize compression library");
-	}
-	else
-		pg_fatal("unhandled mode \"%s\"", mode);
+	CFH->private_data = zstdcs;
 
 	return true;
 }
diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index 1c1675fa2f8..b0ef1980360 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -1761,8 +1761,8 @@ ahwrite(const void *ptr, size_t size, size_t nmemb, ArchiveHandle *AH)
 	{
 		CompressFileHandle *CFH = (CompressFileHandle *) AH->OF;
 
-		if (CFH->write_func(ptr, size * nmemb, CFH))
-			bytes_written = size * nmemb;
+		CFH->write_func(ptr, size * nmemb, CFH);
+		bytes_written = size * nmemb;
 	}
 
 	if (bytes_written != size * nmemb)
diff --git a/src/bin/pg_dump/pg_backup_directory.c b/src/bin/pg_dump/pg_backup_directory.c
index 7f2ac7c7fd1..24bcbe8ee28 100644
--- a/src/bin/pg_dump/pg_backup_directory.c
+++ b/src/bin/pg_dump/pg_backup_directory.c
@@ -347,15 +347,9 @@ _WriteData(ArchiveHandle *AH, const void *data, size_t dLen)
 	lclContext *ctx = (lclContext *) AH->formatData;
 	CompressFileHandle *CFH = ctx->dataFH;
 
-	errno = 0;
-	if (dLen > 0 && !CFH->write_func(data, dLen, CFH))
-	{
-		/* if write didn't set errno, assume problem is no disk space */
-		if (errno == 0)
-			errno = ENOSPC;
-		pg_fatal("could not write to output file: %s",
-				 CFH->get_error_func(CFH));
-	}
+	if (dLen <= 0)
+		return;
+	CFH->write_func(data, dLen, CFH);
 }
 
 /*
@@ -382,7 +376,7 @@ _EndData(ArchiveHandle *AH, TocEntry *te)
 static void
 _PrintFileData(ArchiveHandle *AH, char *filename)
 {
-	size_t		cnt = 0;
+	size_t		cnt;
 	char	   *buf;
 	size_t		buflen;
 	CompressFileHandle *CFH;
@@ -397,7 +391,7 @@ _PrintFileData(ArchiveHandle *AH, char *filename)
 	buflen = DEFAULT_IO_BUFFER_SIZE;
 	buf = pg_malloc(buflen);
 
-	while (CFH->read_func(buf, buflen, &cnt, CFH) && cnt > 0)
+	while ((cnt = CFH->read_func(buf, buflen, CFH)) > 0)
 	{
 		ahwrite(buf, 1, cnt, AH);
 	}
@@ -490,16 +484,7 @@ _WriteByte(ArchiveHandle *AH, const int i)
 	lclContext *ctx = (lclContext *) AH->formatData;
 	CompressFileHandle *CFH = ctx->dataFH;
 
-	errno = 0;
-	if (!CFH->write_func(&c, 1, CFH))
-	{
-		/* if write didn't set errno, assume problem is no disk space */
-		if (errno == 0)
-			errno = ENOSPC;
-		pg_fatal("could not write to output file: %s",
-				 CFH->get_error_func(CFH));
-	}
-
+	CFH->write_func(&c, 1, CFH);
 	return 1;
 }
 
@@ -528,15 +513,7 @@ _WriteBuf(ArchiveHandle *AH, const void *buf, size_t len)
 	lclContext *ctx = (lclContext *) AH->formatData;
 	CompressFileHandle *CFH = ctx->dataFH;
 
-	errno = 0;
-	if (!CFH->write_func(buf, len, CFH))
-	{
-		/* if write didn't set errno, assume problem is no disk space */
-		if (errno == 0)
-			errno = ENOSPC;
-		pg_fatal("could not write to output file: %s",
-				 CFH->get_error_func(CFH));
-	}
+	CFH->write_func(buf, len, CFH);
 }
 
 /*
@@ -551,10 +528,10 @@ _ReadBuf(ArchiveHandle *AH, void *buf, size_t len)
 	CompressFileHandle *CFH = ctx->dataFH;
 
 	/*
-	 * If there was an I/O error, we already exited in readF(), so here we
-	 * exit on short reads.
+	 * We do not expect a short read, so fail if we get one.  The read_func
+	 * already dealt with any outright I/O error.
 	 */
-	if (!CFH->read_func(buf, len, NULL, CFH))
+	if (CFH->read_func(buf, len, CFH) != len)
 		pg_fatal("could not read from input file: end of file");
 }
 
@@ -696,14 +673,7 @@ _EndLO(ArchiveHandle *AH, TocEntry *te, Oid oid)
 
 	/* register the LO in blobs.toc */
 	len = snprintf(buf, sizeof(buf), "%u blob_%u.dat\n", oid, oid);
-	if (!CFH->write_func(buf, len, CFH))
-	{
-		/* if write didn't set errno, assume problem is no disk space */
-		if (errno == 0)
-			errno = ENOSPC;
-		pg_fatal("could not write to LOs TOC file: %s",
-				 CFH->get_error_func(CFH));
-	}
+	CFH->write_func(buf, len, CFH);
 }
 
 /*