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Commit 21633fc6 authored by Qu Wenruo's avatar Qu Wenruo Committed by Chris Mason
Browse files

btrfs: backref: Add special time_seq == (u64)-1 case for 


btrfs_find_all_roots().

Allow btrfs_find_all_roots() to skip all delayed_ref_head lock and tree
lock to do tree search.

This is important for later qgroup implement which will call
find_all_roots() after fs trees are committed.

Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 3b7d00f9

fs/btrfs/backref.c

+29 −6
Original line number Diff line number Diff line
@@ -250,8 +250,12 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, 
	 * the first item to check. But sometimes, we may enter it with

	 * slot==nritems. In that case, go to the next leaf before we continue.

	 */

	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))

	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {

		if (time_seq == (u64)-1)

			ret = btrfs_next_leaf(root, path);

		else

			ret = btrfs_next_old_leaf(root, path, time_seq);

	}



	while (!ret && count < total_refs) {

		eb = path->nodes[0];
@@ -291,6 +295,9 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, 
			eie = NULL;

		}

next:

		if (time_seq == (u64)-1)

			ret = btrfs_next_item(root, path);

		else

			ret = btrfs_next_old_item(root, path, time_seq);

	}
@@ -334,6 +341,8 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, 


	if (path->search_commit_root)

		root_level = btrfs_header_level(root->commit_root);

	else if (time_seq == (u64)-1)

		root_level = btrfs_header_level(root->node);

	else

		root_level = btrfs_old_root_level(root, time_seq);
@@ -343,7 +352,12 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, 
	}



	path->lowest_level = level;

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

	if (time_seq == (u64)-1)

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

					0, 0);

	else

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

					    time_seq);



	/* root node has been locked, we can release @subvol_srcu safely here */

	srcu_read_unlock(&fs_info->subvol_srcu, index);
@@ -879,6 +893,11 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info, 
 *

 * NOTE: This can return values > 0

 *

 * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave

 * much like trans == NULL case, the difference only lies in it will not

 * commit root.

 * The special case is for qgroup to search roots in commit_transaction().

 *

 * FIXME some caching might speed things up

 */

static int find_parent_nodes(struct btrfs_trans_handle *trans,
@@ -917,6 +936,9 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans, 
		path->skip_locking = 1;

	}



	if (time_seq == (u64)-1)

		path->skip_locking = 1;



	/*

	 * grab both a lock on the path and a lock on the delayed ref head.

	 * We need both to get a consistent picture of how the refs look
@@ -931,9 +953,10 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans, 
	BUG_ON(ret == 0);



#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS

	if (trans && likely(trans->type != __TRANS_DUMMY)) {

	if (trans && likely(trans->type != __TRANS_DUMMY) &&

	    time_seq != (u64)-1) {

#else

	if (trans) {

	if (trans && time_seq != (u64)-1) {

#endif

		/*

		 * look if there are updates for this ref queued and lock the