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Commit 8445f61c authored by Jan Schmidt's avatar Jan Schmidt
Browse files

Btrfs: use the tree modification log for backref resolving 



This enables backref resolving on life trees while they are changing. This
is a prerequisite for quota groups and just nice to have for everything
else.

Signed-off-by: default avatarJan Schmidt <list.btrfs@jan-o-sch.net>
parent 5d9e75c4

fs/btrfs/backref.c

+27 −16
Original line number Diff line number Diff line
@@ -231,6 +231,7 @@ add_parent: 
 */

static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,

					int search_commit_root,

					u64 time_seq,

					struct __prelim_ref *ref,

					struct ulist *parents,

					const u64 *extent_item_pos)
@@ -266,7 +267,7 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, 
		goto out;



	path->lowest_level = level;

	ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path, 0, 0);

	ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);

	pr_debug("search slot in root %llu (level %d, ref count %d) returned "

		 "%d for key (%llu %u %llu)\n",

		 (unsigned long long)ref->root_id, level, ref->count, ret,
@@ -305,7 +306,7 @@ out: 
 * resolve all indirect backrefs from the list

 */

static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,

				   int search_commit_root,

				   int search_commit_root, u64 time_seq,

				   struct list_head *head,

				   const u64 *extent_item_pos)

{
@@ -333,7 +334,8 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, 
		if (ref->count == 0)

			continue;

		err = __resolve_indirect_ref(fs_info, search_commit_root,

					     ref, parents, extent_item_pos);

					     time_seq, ref, parents,

					     extent_item_pos);

		if (err) {

			if (ret == 0)

				ret = err;
@@ -750,7 +752,8 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info, 
 */

static int find_parent_nodes(struct btrfs_trans_handle *trans,

			     struct btrfs_fs_info *fs_info, u64 bytenr,

			     u64 seq, struct ulist *refs, struct ulist *roots,

			     u64 delayed_ref_seq, u64 time_seq,

			     struct ulist *refs, struct ulist *roots,

			     const u64 *extent_item_pos)

{

	struct btrfs_key key;
@@ -813,7 +816,8 @@ again: 
				btrfs_put_delayed_ref(&head->node);

				goto again;

			}

			ret = __add_delayed_refs(head, seq, &prefs_delayed);

			ret = __add_delayed_refs(head, delayed_ref_seq,

						 &prefs_delayed);

			if (ret) {

				spin_unlock(&delayed_refs->lock);

				goto out;
@@ -854,8 +858,8 @@ again: 
	if (ret)

		goto out;



	ret = __resolve_indirect_refs(fs_info, search_commit_root, &prefs,

				      extent_item_pos);

	ret = __resolve_indirect_refs(fs_info, search_commit_root, time_seq,

				      &prefs, extent_item_pos);

	if (ret)

		goto out;
@@ -945,7 +949,8 @@ static void free_leaf_list(struct ulist *blocks) 
 */

static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,

				struct btrfs_fs_info *fs_info, u64 bytenr,

				u64 seq, struct ulist **leafs,

				u64 delayed_ref_seq, u64 time_seq,

				struct ulist **leafs,

				const u64 *extent_item_pos)

{

	struct ulist *tmp;
@@ -960,8 +965,8 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, 
		return -ENOMEM;

	}



	ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp,

				extent_item_pos);

	ret = find_parent_nodes(trans, fs_info, bytenr, delayed_ref_seq,

				time_seq, *leafs, tmp, extent_item_pos);

	ulist_free(tmp);



	if (ret < 0 && ret != -ENOENT) {
@@ -987,7 +992,8 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, 
 */

int btrfs_find_all_roots(struct btrfs_trans_handle *trans,

				struct btrfs_fs_info *fs_info, u64 bytenr,

				u64 seq, struct ulist **roots)

				u64 delayed_ref_seq, u64 time_seq,

				struct ulist **roots)

{

	struct ulist *tmp;

	struct ulist_node *node = NULL;
@@ -1005,8 +1011,8 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans, 


	ULIST_ITER_INIT(&uiter);

	while (1) {

		ret = find_parent_nodes(trans, fs_info, bytenr, seq,

					tmp, *roots, NULL);

		ret = find_parent_nodes(trans, fs_info, bytenr, delayed_ref_seq,

					time_seq, tmp, *roots, NULL);

		if (ret < 0 && ret != -ENOENT) {

			ulist_free(tmp);

			ulist_free(*roots);
@@ -1338,7 +1344,8 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info, 
	struct ulist *roots = NULL;

	struct ulist_node *ref_node = NULL;

	struct ulist_node *root_node = NULL;

	struct seq_list seq_elem;

	struct seq_list seq_elem = {};

	struct seq_list tree_mod_seq_elem = {};

	struct ulist_iterator ref_uiter;

	struct ulist_iterator root_uiter;

	struct btrfs_delayed_ref_root *delayed_refs = NULL;
@@ -1357,17 +1364,20 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info, 
		spin_lock(&delayed_refs->lock);

		btrfs_get_delayed_seq(delayed_refs, &seq_elem);

		spin_unlock(&delayed_refs->lock);

		btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);

	}



	ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,

				   seq_elem.seq, &refs, &extent_item_pos);

				   seq_elem.seq, tree_mod_seq_elem.seq, &refs,

				   &extent_item_pos);

	if (ret)

		goto out;



	ULIST_ITER_INIT(&ref_uiter);

	while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {

		ret = btrfs_find_all_roots(trans, fs_info, ref_node->val,

						seq_elem.seq, &roots);

						seq_elem.seq,

						tree_mod_seq_elem.seq, &roots);

		if (ret)

			break;

		ULIST_ITER_INIT(&root_uiter);
@@ -1388,6 +1398,7 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info, 
	ulist_free(roots);

out:

	if (!search_commit_root) {

		btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);

		btrfs_put_delayed_seq(delayed_refs, &seq_elem);

		btrfs_end_transaction(trans, fs_info->extent_root);

	}

fs/btrfs/backref.h

+2 −1
Original line number Diff line number Diff line
@@ -58,7 +58,8 @@ int paths_from_inode(u64 inum, struct inode_fs_paths *ipath); 


int btrfs_find_all_roots(struct btrfs_trans_handle *trans,

				struct btrfs_fs_info *fs_info, u64 bytenr,

				u64 seq, struct ulist **roots);

				u64 delayed_ref_seq, u64 time_seq,

				struct ulist **roots);



struct btrfs_data_container *init_data_container(u32 total_bytes);

struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,