btrfs: pass root owner to read_tree_block

In order to properly set the lockdep class of a newly allocated block we
need to know the owner of the block.  For non-refcounted trees this is
straightforward, we always know in advance what tree we're reading from.
For refcounted trees we don't necessarily know, however all refcounted
trees share the same lockdep class name, tree-<level>.

Fix all the callers of read_tree_block() to pass in the root objectid
we're using.  In places like relocation and backref we could probably
unconditionally use 0, but just in case use the root when we have it,
otherwise use 0 in the cases we don't have the root as it's going to be
a refcounted tree anyway.

This is a preparation patch for further changes.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/backref.c

@@ -783,8 +783,8 @@ static int add_missing_keys(struct btrfs_fs_info *fs_info,
 		BUG_ON(ref->key_for_search.type);
 		BUG_ON(!ref->wanted_disk_byte);
 
-		eb = read_tree_block(fs_info, ref->wanted_disk_byte, 0,
-				     ref->level - 1, NULL);
+		eb = read_tree_block(fs_info, ref->wanted_disk_byte,
+				     ref->root_id, 0, ref->level - 1, NULL);
 		if (IS_ERR(eb)) {
 			free_pref(ref);
 			return PTR_ERR(eb);
@@ -1331,7 +1331,7 @@ again:
 				struct extent_buffer *eb;
 
 				eb = read_tree_block(fs_info, ref->parent, 0,
-						     ref->level, NULL);
+						     0, ref->level, NULL);
 				if (IS_ERR(eb)) {
 					ret = PTR_ERR(eb);
 					goto out;

fs/btrfs/ctree.c

@@ -1353,7 +1353,8 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
 	if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
 		btrfs_tree_read_unlock(eb_root);
 		free_extent_buffer(eb_root);
-		old = read_tree_block(fs_info, logical, 0, level, NULL);
+		old = read_tree_block(fs_info, logical, root->root_key.objectid,
+				      0, level, NULL);
 		if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) {
 			if (!IS_ERR(old))
 				free_extent_buffer(old);
@@ -1760,6 +1761,7 @@ struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
 
 	btrfs_node_key_to_cpu(parent, &first_key, slot);
 	eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot),
+			     btrfs_header_owner(parent),
 			     btrfs_node_ptr_generation(parent, slot),
 			     level - 1, &first_key);
 	if (!IS_ERR(eb) && !extent_buffer_uptodate(eb)) {
@@ -2349,8 +2351,8 @@ read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
 		reada_for_search(fs_info, p, level, slot, key->objectid);
 
 	ret = -EAGAIN;
-	tmp = read_tree_block(fs_info, blocknr, gen, parent_level - 1,
-			      &first_key);
+	tmp = read_tree_block(fs_info, blocknr, root->root_key.objectid,
+			      gen, parent_level - 1, &first_key);
 	if (!IS_ERR(tmp)) {
 		/*
 		 * If the read above didn't mark this buffer up to date,

fs/btrfs/disk-io.c

@@ -966,13 +966,14 @@ struct extent_buffer *btrfs_find_create_tree_block(
  * Read tree block at logical address @bytenr and do variant basic but critical
  * verification.
  *
+ * @owner_root:		the objectid of the root owner for this block.
  * @parent_transid:	expected transid of this tree block, skip check if 0
  * @level:		expected level, mandatory check
  * @first_key:		expected key in slot 0, skip check if NULL
  */
 struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
-				      u64 parent_transid, int level,
-				      struct btrfs_key *first_key)
+				      u64 owner_root, u64 parent_transid,
+				      int level, struct btrfs_key *first_key)
 {
 	struct extent_buffer *buf = NULL;
 	int ret;
@@ -1295,7 +1296,7 @@ static struct btrfs_root *read_tree_root_path(struct btrfs_root *tree_root,
 	level = btrfs_root_level(&root->root_item);
 	root->node = read_tree_block(fs_info,
 				     btrfs_root_bytenr(&root->root_item),
-				     generation, level, NULL);
+				     key->objectid, generation, level, NULL);
 	if (IS_ERR(root->node)) {
 		ret = PTR_ERR(root->node);
 		root->node = NULL;
@@ -2249,8 +2250,9 @@ static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
 		return -ENOMEM;
 
 	log_tree_root->node = read_tree_block(fs_info, bytenr,
-					      fs_info->generation + 1,
-					      level, NULL);
+					      BTRFS_TREE_LOG_OBJECTID,
+					      fs_info->generation + 1, level,
+					      NULL);
 	if (IS_ERR(log_tree_root->node)) {
 		btrfs_warn(fs_info, "failed to read log tree");
 		ret = PTR_ERR(log_tree_root->node);
@@ -2636,6 +2638,7 @@ static int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
 		generation = btrfs_super_generation(sb);
 		level = btrfs_super_root_level(sb);
 		tree_root->node = read_tree_block(fs_info, btrfs_super_root(sb),
+						  BTRFS_ROOT_TREE_OBJECTID,
 						  generation, level, NULL);
 		if (IS_ERR(tree_root->node)) {
 			handle_error = true;
@@ -3124,6 +3127,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 
 	chunk_root->node = read_tree_block(fs_info,
 					   btrfs_super_chunk_root(disk_super),
+					   BTRFS_CHUNK_TREE_OBJECTID,
 					   generation, level, NULL);
 	if (IS_ERR(chunk_root->node) ||
 	    !extent_buffer_uptodate(chunk_root->node)) {

fs/btrfs/disk-io.h

@@ -43,8 +43,8 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info);
 int btrfs_verify_level_key(struct extent_buffer *eb, int level,
 			   struct btrfs_key *first_key, u64 parent_transid);
 struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
-				      u64 parent_transid, int level,
-				      struct btrfs_key *first_key);
+				      u64 owner_root, u64 parent_transid,
+				      int level, struct btrfs_key *first_key);
 struct extent_buffer *btrfs_find_create_tree_block(
 						struct btrfs_fs_info *fs_info,
 						u64 bytenr);

fs/btrfs/extent-tree.c

@@ -5077,8 +5077,8 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
 	if (!next) {
 		if (reada && level == 1)
 			reada_walk_down(trans, root, wc, path);
-		next = read_tree_block(fs_info, bytenr, generation, level - 1,
-				       &first_key);
+		next = read_tree_block(fs_info, bytenr, root->root_key.objectid,
+				       generation, level - 1, &first_key);
 		if (IS_ERR(next)) {
 			return PTR_ERR(next);
 		} else if (!extent_buffer_uptodate(next)) {

fs/btrfs/print-tree.c

@@ -390,6 +390,7 @@ void btrfs_print_tree(struct extent_buffer *c, bool follow)
 
 		btrfs_node_key_to_cpu(c, &first_key, i);
 		next = read_tree_block(fs_info, btrfs_node_blockptr(c, i),
+				       btrfs_header_owner(c),
 				       btrfs_node_ptr_generation(c, i),
 				       level - 1, &first_key);
 		if (IS_ERR(next)) {

fs/btrfs/qgroup.c

@@ -4208,7 +4208,7 @@ int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
 	spin_unlock(&blocks->lock);
 
 	/* Read out reloc subtree root */
-	reloc_eb = read_tree_block(fs_info, block->reloc_bytenr,
+	reloc_eb = read_tree_block(fs_info, block->reloc_bytenr, 0,
 				   block->reloc_generation, block->level,
 				   &block->first_key);
 	if (IS_ERR(reloc_eb)) {

fs/btrfs/relocation.c

@@ -2413,7 +2413,7 @@ static int get_tree_block_key(struct btrfs_fs_info *fs_info,
 {
 	struct extent_buffer *eb;
 
-	eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
+	eb = read_tree_block(fs_info, block->bytenr, 0, block->key.offset,
 			     block->level, NULL);
 	if (IS_ERR(eb)) {
 		return PTR_ERR(eb);
@@ -3038,7 +3038,7 @@ int add_data_references(struct reloc_control *rc,
 	while ((ref_node = ulist_next(leaves, &leaf_uiter))) {
 		struct extent_buffer *eb;
 
-		eb = read_tree_block(fs_info, ref_node->val, 0, 0, NULL);
+		eb = read_tree_block(fs_info, ref_node->val, 0, 0, 0, NULL);
 		if (IS_ERR(eb)) {
 			ret = PTR_ERR(eb);
 			break;