From 08cb5d848314006111b0c379db6a1fce220579aa Mon Sep 17 00:00:00 2001
From: Vladislav Vaintroub <wlad@mariadb.com>
Date: Wed, 31 Mar 2021 14:23:56 +0200
Subject: MDEV-25221 Do not remove source file, if copy_file() fails in
 mariabackup --move-back

Remove an incompletely copied destination file.
---
 extra/mariabackup/backup_copy.cc                   | 14 +++++++-----
 extra/mariabackup/datasink.h                       |  6 ++++++
 extra/mariabackup/ds_archive.cc                    |  1 +
 extra/mariabackup/ds_buffer.cc                     |  1 +
 extra/mariabackup/ds_compress.cc                   |  1 +
 extra/mariabackup/ds_local.cc                      |  6 ++++++
 extra/mariabackup/ds_stdout.cc                     |  1 +
 extra/mariabackup/ds_tmpfile.cc                    |  1 +
 extra/mariabackup/ds_xbstream.cc                   |  1 +
 .../suite/mariabackup/error_during_copyback.result |  9 ++++++++
 .../suite/mariabackup/error_during_copyback.test   | 25 ++++++++++++++++++++++
 11 files changed, 61 insertions(+), 5 deletions(-)
 create mode 100644 mysql-test/suite/mariabackup/error_during_copyback.result
 create mode 100644 mysql-test/suite/mariabackup/error_during_copyback.test

diff --git a/extra/mariabackup/backup_copy.cc b/extra/mariabackup/backup_copy.cc
index d3fa3605c21..5637ec3d4d7 100644
--- a/extra/mariabackup/backup_copy.cc
+++ b/extra/mariabackup/backup_copy.cc
@@ -1066,6 +1066,7 @@ copy_file(ds_ctxt_t *datasink,
 	ds_file_t		*dstfile = NULL;
 	datafile_cur_t		 cursor;
 	xb_fil_cur_result_t	 res;
+	DBUG_ASSERT(datasink->datasink->remove);
 	const char	*dst_path =
 		(xtrabackup_copy_back || xtrabackup_move_back)?
 		dst_file_path : trim_dotslash(dst_file_path);
@@ -1091,6 +1092,7 @@ copy_file(ds_ctxt_t *datasink,
 		if (ds_write(dstfile, cursor.buf, cursor.buf_read)) {
 			goto error;
 		}
+		DBUG_EXECUTE_IF("copy_file_error", errno=ENOSPC;goto error;);
 	}
 
 	if (res == XB_FIL_CUR_ERROR) {
@@ -1112,6 +1114,7 @@ copy_file(ds_ctxt_t *datasink,
 error:
 	datafile_close(&cursor);
 	if (dstfile != NULL) {
+		datasink->datasink->remove(dstfile->path);
 		ds_close(dstfile);
 	}
 
@@ -1156,17 +1159,18 @@ move_file(ds_ctxt_t *datasink,
 
 	if (my_rename(src_file_path, dst_file_path_abs, MYF(0)) != 0) {
 		if (my_errno == EXDEV) {
-			bool ret;
-			ret = copy_file(datasink, src_file_path,
-					dst_file_path, thread_n);
+			/* Fallback to copy/unlink */
+			if(!copy_file(datasink, src_file_path,
+					dst_file_path, thread_n))
+					return false;
 			msg(thread_n,"Removing %s", src_file_path);
 			if (unlink(src_file_path) != 0) {
 				my_strerror(errbuf, sizeof(errbuf), errno);
-				msg("Error: unlink %s failed: %s",
+				msg("Warning: unlink %s failed: %s",
 					src_file_path,
 					errbuf);
 			}
-			return(ret);
+			return true;
 		}
 		my_strerror(errbuf, sizeof(errbuf), my_errno);
 		msg("Can not move file %s to %s: %s",
diff --git a/extra/mariabackup/datasink.h b/extra/mariabackup/datasink.h
index 201bbfd3267..5c82556b9ba 100644
--- a/extra/mariabackup/datasink.h
+++ b/extra/mariabackup/datasink.h
@@ -50,9 +50,15 @@ struct datasink_struct {
 	ds_file_t *(*open)(ds_ctxt_t *ctxt, const char *path, MY_STAT *stat);
 	int (*write)(ds_file_t *file, const unsigned char *buf, size_t len);
 	int (*close)(ds_file_t *file);
+	int (*remove)(const char *path);
 	void (*deinit)(ds_ctxt_t *ctxt);
 };
 
+
+static inline int dummy_remove(const char *) {
+	return 0;
+}
+
 /* Supported datasink types */
 typedef enum {
 	DS_TYPE_STDOUT,
diff --git a/extra/mariabackup/ds_archive.cc b/extra/mariabackup/ds_archive.cc
index 3826029e120..18f13fbcf3a 100644
--- a/extra/mariabackup/ds_archive.cc
+++ b/extra/mariabackup/ds_archive.cc
@@ -56,6 +56,7 @@ datasink_t datasink_archive = {
 	&archive_open,
 	&archive_write,
 	&archive_close,
+	&dummy_remove,
 	&archive_deinit
 };
 
diff --git a/extra/mariabackup/ds_buffer.cc b/extra/mariabackup/ds_buffer.cc
index e906edc9e84..9dc040d533b 100644
--- a/extra/mariabackup/ds_buffer.cc
+++ b/extra/mariabackup/ds_buffer.cc
@@ -54,6 +54,7 @@ datasink_t datasink_buffer = {
 	&buffer_open,
 	&buffer_write,
 	&buffer_close,
+	&dummy_remove,
 	&buffer_deinit
 };
 
diff --git a/extra/mariabackup/ds_compress.cc b/extra/mariabackup/ds_compress.cc
index fb4f3a75bb6..23de4d85116 100644
--- a/extra/mariabackup/ds_compress.cc
+++ b/extra/mariabackup/ds_compress.cc
@@ -74,6 +74,7 @@ datasink_t datasink_compress = {
 	&compress_open,
 	&compress_write,
 	&compress_close,
+	&dummy_remove,
 	&compress_deinit
 };
 
diff --git a/extra/mariabackup/ds_local.cc b/extra/mariabackup/ds_local.cc
index 0f13ddfe9a9..2f0ad2d8705 100644
--- a/extra/mariabackup/ds_local.cc
+++ b/extra/mariabackup/ds_local.cc
@@ -44,12 +44,18 @@ static int local_write(ds_file_t *file, const uchar *buf, size_t len);
 static int local_close(ds_file_t *file);
 static void local_deinit(ds_ctxt_t *ctxt);
 
+static int local_remove(const char *path)
+{
+	return unlink(path);
+}
+
 extern "C" {
 datasink_t datasink_local = {
 	&local_init,
 	&local_open,
 	&local_write,
 	&local_close,
+	&local_remove,
 	&local_deinit
 };
 }
diff --git a/extra/mariabackup/ds_stdout.cc b/extra/mariabackup/ds_stdout.cc
index 9398482feb9..a4abbe426b6 100644
--- a/extra/mariabackup/ds_stdout.cc
+++ b/extra/mariabackup/ds_stdout.cc
@@ -39,6 +39,7 @@ datasink_t datasink_stdout = {
 	&stdout_open,
 	&stdout_write,
 	&stdout_close,
+	&dummy_remove,
 	&stdout_deinit
 };
 
diff --git a/extra/mariabackup/ds_tmpfile.cc b/extra/mariabackup/ds_tmpfile.cc
index ddb23bf469d..9eadd36bec0 100644
--- a/extra/mariabackup/ds_tmpfile.cc
+++ b/extra/mariabackup/ds_tmpfile.cc
@@ -50,6 +50,7 @@ datasink_t datasink_tmpfile = {
 	&tmpfile_open,
 	&tmpfile_write,
 	&tmpfile_close,
+	&dummy_remove,
 	&tmpfile_deinit
 };
 
diff --git a/extra/mariabackup/ds_xbstream.cc b/extra/mariabackup/ds_xbstream.cc
index 105c89d05f7..3b60456f8ed 100644
--- a/extra/mariabackup/ds_xbstream.cc
+++ b/extra/mariabackup/ds_xbstream.cc
@@ -50,6 +50,7 @@ datasink_t datasink_xbstream = {
 	&xbstream_open,
 	&xbstream_write,
 	&xbstream_close,
+	&dummy_remove,
 	&xbstream_deinit
 };
 
diff --git a/mysql-test/suite/mariabackup/error_during_copyback.result b/mysql-test/suite/mariabackup/error_during_copyback.result
new file mode 100644
index 00000000000..9b12c1135d2
--- /dev/null
+++ b/mysql-test/suite/mariabackup/error_during_copyback.result
@@ -0,0 +1,9 @@
+CREATE TABLE t(i INT) ENGINE INNODB;
+INSERT INTO t VALUES(1);
+# xtrabackup backup
+# xtrabackup prepare
+# restart server
+SELECT * FROM t;
+i
+1
+DROP TABLE t;
diff --git a/mysql-test/suite/mariabackup/error_during_copyback.test b/mysql-test/suite/mariabackup/error_during_copyback.test
new file mode 100644
index 00000000000..3ec9fbfc3c3
--- /dev/null
+++ b/mysql-test/suite/mariabackup/error_during_copyback.test
@@ -0,0 +1,25 @@
+--source include/have_debug.inc
+CREATE TABLE t(i INT) ENGINE INNODB;
+INSERT INTO t VALUES(1);
+echo # xtrabackup backup;
+let $targetdir=$MYSQLTEST_VARDIR/tmp/backup;
+--disable_result_log
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir;
+--enable_result_log
+echo # xtrabackup prepare;
+--disable_result_log
+exec $XTRABACKUP  --prepare --target-dir=$targetdir;
+let $_datadir= `SELECT @@datadir`;
+--source include/shutdown_mysqld.inc
+rmdir $_datadir;
+error 1;
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --copy-back  --datadir=$_datadir --target-dir=$targetdir --dbug=+d,copy_file_error;
+list_files $_datadir;
+rmdir $_datadir;
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --copy-back --datadir=$_datadir --target-dir=$targetdir;
+echo # restart server;
+--source include/start_mysqld.inc
+SELECT * FROM t;
+DROP TABLE t;
+rmdir $targetdir;
+
-- 
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