btrfs-progs: raid56: Introduce raid56 header for later recovery usage

Introduce a new header, kernel-lib/raid56.h, for later raid56 works.

It contains 2 functions, from original btrfs-progs code:
void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data);

Will be expanded later and some part of it(RAID6 recover part) may keep
sync with kernel later.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
[ unify gpl header, rename header macro ]
Signed-off-by: David Sterba <dsterba@suse.com>

Makefile

@@ -108,8 +108,8 @@ libbtrfs_objects = send-stream.o send-utils.o kernel-lib/rbtree.o btrfs-list.o \
 		   uuid-tree.o utils-lib.o rbtree-utils.o
 libbtrfs_headers = send-stream.h send-utils.h send.h kernel-lib/rbtree.h btrfs-list.h \
 	       kernel-lib/crc32c.h kernel-lib/list.h kerncompat.h \
-	       kernel-lib/radix-tree.h kernel-lib/sizes.h extent-cache.h \
+	       kernel-lib/radix-tree.h kernel-lib/sizes.h kernel-lib/raid56.h \
-	       extent_io.h ioctl.h ctree.h btrfsck.h version.h
+	       extent-cache.h extent_io.h ioctl.h ctree.h btrfsck.h version.h
 convert_objects = convert/main.o convert/common.o convert/source-fs.o \
 		  convert/source-ext2.o
 mkfs_objects = mkfs/main.o mkfs/common.o

disk-io.h

@@ -193,8 +193,4 @@ int write_tree_block(struct btrfs_trans_handle *trans,
 		     struct extent_buffer *eb);
 int write_and_map_eb(struct btrfs_root *root, struct extent_buffer *eb);
 
-/* raid56.c */
-void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
-int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data);
-
 #endif

kernel-lib/raid56.h

@@ -0,0 +1,28 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+/*
+ * Original headers from kernel library for RAID5/6 calculations, not from
+ * btrfs kernel header.
+ */
+
+#ifndef __BTRFS_PROGS_RAID56_H__
+#define __BTRFS_PROGS_RAID56_H__
+
+void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
+int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data);
+
+#endif

volumes.c

@@ -28,6 +28,7 @@
 #include "print-tree.h"
 #include "volumes.h"
 #include "utils.h"
+#include "kernel-lib/raid56.h"
 
 struct stripe {
 	struct btrfs_device *dev;