Add root tree pointer transaction ids

This patch adds transaction IDs to root tree pointers.
Transaction IDs in tree pointers are compared with the
generation numbers in block headers when reading root
blocks of trees. This can detect some types of IO errors.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

1 files changed, 22 insertions, 4 deletions

diff --git a/disk-io.c b/disk-io.c
index f2cbd4af..06815728 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -274,6 +274,8 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
 			break;
 		btrfs_set_root_bytenr(&root->root_item,
 				       root->node->start);
+		btrfs_set_root_generation(&root->root_item,
+					  trans->transid);
 		root->root_item.level = btrfs_header_level(root->node);
 		ret = btrfs_update_root(trans, tree_root,
 					&root->root_key,
@@ -289,6 +291,12 @@ static int commit_tree_roots(struct btrfs_trans_handle *trans,
 {
 	struct btrfs_root *root;
 	struct list_head *next;
+	struct extent_buffer *eb;
+
+	eb = fs_info->tree_root->node;
+	extent_buffer_get(eb);
+	btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
+	free_extent_buffer(eb);
 
 	while(!list_empty(&fs_info->dirty_cowonly_roots)) {
 		next = fs_info->dirty_cowonly_roots.next;
@@ -345,6 +353,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
 	root->root_key.offset = trans->transid;
 	btrfs_set_root_bytenr(&root->root_item, root->node->start);
+	btrfs_set_root_generation(&root->root_item, root->root_key.offset);
 	root->root_item.level = btrfs_header_level(root->node);
 	ret = btrfs_insert_root(trans, fs_info->tree_root,
 				&root->root_key, &root->root_item);
@@ -395,6 +404,7 @@ static int find_and_setup_root(struct btrfs_root *tree_root,
 {
 	int ret;
 	u32 blocksize;
+	u64 generation;
 
 	__setup_root(tree_root->nodesize, tree_root->leafsize,
 		     tree_root->sectorsize, tree_root->stripesize,
@@ -404,8 +414,9 @@ static int find_and_setup_root(struct btrfs_root *tree_root,
 	BUG_ON(ret);
 
 	blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
+	generation = btrfs_root_generation(&root->root_item);
 	root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
-				     blocksize, 0);
+				     blocksize, generation);
 	BUG_ON(!root->node);
 	return 0;
 }
@@ -428,6 +439,7 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 	struct btrfs_root *tree_root = fs_info->tree_root;
 	struct btrfs_path *path;
 	struct extent_buffer *l;
+	u64 generation;
 	u32 blocksize;
 	int ret = 0;
 
@@ -470,9 +482,10 @@ out:
 		free(root);
 		return ERR_PTR(ret);
 	}
+	generation = btrfs_root_generation(&root->root_item);
 	blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 	root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
-				     blocksize, 0);
+				     blocksize, generation);
 	BUG_ON(!root->node);
 insert:
 	root->ref_cows = 1;
@@ -506,6 +519,7 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 	u32 leafsize;
 	u32 blocksize;
 	u32 stripesize;
+	u64 generation;
 	struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 	struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 	struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
@@ -604,13 +618,14 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 	BUG_ON(ret);
 	blocksize = btrfs_level_size(tree_root,
 				     btrfs_super_chunk_root_level(disk_super));
+	generation = btrfs_super_chunk_root_generation(disk_super);
 
 	__setup_root(nodesize, leafsize, sectorsize, stripesize,
 		     chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
 
 	chunk_root->node = read_tree_block(chunk_root,
 					   btrfs_super_chunk_root(disk_super),
-					   blocksize, 0);
+					   blocksize, generation);
 
 	BUG_ON(!chunk_root->node);
 
@@ -623,10 +638,11 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
 
 	blocksize = btrfs_level_size(tree_root,
 				     btrfs_super_root_level(disk_super));
+	generation = btrfs_super_generation(disk_super);
 
 	tree_root->node = read_tree_block(tree_root,
 					  btrfs_super_root(disk_super),
-					  blocksize, 0);
+					  blocksize, generation);
 	BUG_ON(!tree_root->node);
 	ret = find_and_setup_root(tree_root, fs_info,
 				  BTRFS_EXTENT_TREE_OBJECTID, extent_root);
@@ -706,6 +722,8 @@ int write_ctree_super(struct btrfs_trans_handle *trans,
 				   chunk_root->node->start);
 	btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
 					 btrfs_header_level(chunk_root->node));
+	btrfs_set_super_chunk_root_generation(&root->fs_info->super_copy,
+				btrfs_header_generation(chunk_root->node));
 	write_extent_buffer(root->fs_info->sb_buffer,
 			    &root->fs_info->super_copy, 0,
 			    sizeof(root->fs_info->super_copy));