uuids

Makefile

@@ -5,7 +5,7 @@ headers = radix-tree.h ctree.h disk-io.h kerncompat.h print-tree.h list.h \
 objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
 	  root-tree.o dir-item.o hash.o file-item.o inode-item.o \
 	  inode-map.o \
-
+#
 # if you don't have sparse installed, use ls instead
 CHECKFLAGS=-D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise \
 		-Wcontext -Wcast-truncate -Wuninitialized -Wshadow -Wundef
@@ -19,13 +19,13 @@ check=sparse $(CHECKFLAGS)
 all: bit-radix-test tester debug-tree quick-test dir-test tags mkfs.btrfs
 
 mkfs.btrfs: $(objects) mkfs.o
-	gcc $(CFLAGS) -o mkfs.btrfs $(objects) mkfs.o
+	gcc $(CFLAGS) -o mkfs.btrfs $(objects) mkfs.o -luuid
 
 bit-radix-test: $(objects) bit-radix.o
 	gcc $(CFLAGS) -o bit-radix-test $(objects) bit-radix.o
 
 debug-tree: $(objects) debug-tree.o
-	gcc $(CFLAGS) -o debug-tree $(objects) debug-tree.o
+	gcc $(CFLAGS) -o debug-tree $(objects) debug-tree.o -luuid
 
 tester: $(objects) random-test.o
 	gcc $(CFLAGS) -o tester $(objects) random-test.o

debug-tree.c

@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <uuid/uuid.h>
 #include "kerncompat.h"
 #include "radix-tree.h"
 #include "ctree.h"
@@ -10,6 +11,7 @@
 int main(int ac, char **av) {
 	struct btrfs_super_block super;
 	struct btrfs_root *root;
+	char uuidbuf[37];
 
 	if (ac != 2) {
 		fprintf(stderr, "usage: %s device\n", av[0]);
@@ -34,5 +36,8 @@ int main(int ac, char **av) {
 			 root->fs_info->tree_root->node);
 	printf("total blocks %Lu\n", btrfs_super_total_blocks(&super));
 	printf("blocks used %Lu\n", btrfs_super_blocks_used(&super));
+	uuidbuf[36] = '\0';
+	uuid_unparse(super.fsid, uuidbuf);
+	printf("uuid %s\n", uuidbuf);
 	return 0;
 }

disk-io.c

@@ -21,6 +21,9 @@ static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
 	if (root->node && btrfs_header_parentid(&buf->node.header) !=
 	    btrfs_header_parentid(&root->node->node.header))
 		BUG();
+	if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
+		   sizeof(buf->node.header.fsid)))
+		BUG();
 	return 0;
 }
 

extent-tree.c

@@ -461,6 +461,8 @@ struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 	dirty_tree_block(trans, root, buf);
 	btrfs_set_header_generation(&buf->node.header,
 				    root->root_key.offset + 1);
+	memcpy(buf->node.header.fsid, root->fs_info->disk_super->fsid,
+	       sizeof(buf->node.header.fsid));
 	return buf;
 }
 

mkfs.c

@@ -9,6 +9,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <uuid/uuid.h>
 #include "kerncompat.h"
 #include "radix-tree.h"
 #include "ctree.h"
@@ -99,6 +100,7 @@ int mkfs(int fd, u64 num_blocks, u32 blocksize)
 	btrfs_set_super_blocksize(&super, blocksize);
 	btrfs_set_super_total_blocks(&super, num_blocks);
 	btrfs_set_super_blocks_used(&super, start_block + 5);
+	uuid_generate(super.fsid);
 
 	block = malloc(blocksize);
 	memset(block, 0, blocksize);
@@ -115,6 +117,8 @@ int mkfs(int fd, u64 num_blocks, u32 blocksize)
 	btrfs_set_header_blocknr(&empty_leaf->header, start_block + 1);
 	btrfs_set_header_nritems(&empty_leaf->header, 3);
 	btrfs_set_header_generation(&empty_leaf->header, 0);
+	memcpy(empty_leaf->header.fsid, super.fsid,
+	       sizeof(empty_leaf->header.fsid));
 
 	/* create the items for the root tree */
 	btrfs_set_root_blocknr(&root_item, start_block + 2);