diff --git a/cache.h b/cache.h
index 22b7b8129072f3905c68f02fe19f463bdb738b9e..2981eec7f87dcc24dd0edf58005e164d843e059c 100644
--- a/cache.h
+++ b/cache.h
@@ -1482,9 +1482,13 @@ extern const char *git_mailmap_blob;
 extern void maybe_flush_or_die(FILE *, const char *);
 __attribute__((format (printf, 2, 3)))
 extern void fprintf_or_die(FILE *, const char *fmt, ...);
+
+#define COPY_READ_ERROR (-2)
+#define COPY_WRITE_ERROR (-3)
 extern int copy_fd(int ifd, int ofd);
 extern int copy_file(const char *dst, const char *src, int mode);
 extern int copy_file_with_time(const char *dst, const char *src, int mode);
+
 extern void write_or_die(int fd, const void *buf, size_t count);
 extern int write_or_whine(int fd, const void *buf, size_t count, const char *msg);
 extern int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg);
diff --git a/copy.c b/copy.c
index f2970ec46282a07593366c598f688e5d70c05c83..574fa1f09dadc2e9cc9a39702bafb352f71a56c4 100644
--- a/copy.c
+++ b/copy.c
@@ -7,13 +7,10 @@ int copy_fd(int ifd, int ofd)
 		ssize_t len = xread(ifd, buffer, sizeof(buffer));
 		if (!len)
 			break;
-		if (len < 0) {
-			return error("copy-fd: read returned %s",
-				     strerror(errno));
-		}
+		if (len < 0)
+			return COPY_READ_ERROR;
 		if (write_in_full(ofd, buffer, len) < 0)
-			return error("copy-fd: write returned %s",
-				     strerror(errno));
+			return COPY_WRITE_ERROR;
 	}
 	return 0;
 }
@@ -43,6 +40,14 @@ int copy_file(const char *dst, const char *src, int mode)
 		return fdo;
 	}
 	status = copy_fd(fdi, fdo);
+	switch (status) {
+	case COPY_READ_ERROR:
+		error("copy-fd: read returned %s", strerror(errno));
+		break;
+	case COPY_WRITE_ERROR:
+		error("copy-fd: write returned %s", strerror(errno));
+		break;
+	}
 	close(fdi);
 	if (close(fdo) != 0)
 		return error("%s: close error: %s", dst, strerror(errno));
diff --git a/lockfile.c b/lockfile.c
index 4f16ee78ce3dbc263a762a8800dfe9ddfcfaecd5..beba0ed48038f020e7992187dee1a09cfc9c2c9f 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -206,7 +206,7 @@ int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
 		int save_errno = errno;
 
 		if (flags & LOCK_DIE_ON_ERROR)
-			exit(128);
+			die("failed to prepare '%s' for appending", path);
 		close(orig_fd);
 		rollback_lock_file(lk);
 		errno = save_errno;