btrfs-progs: Pull free space tree related code from kernel

To help implement free space tree checker in user space some kernel
function are necessary, namely iterating/deleting/adding freespace
items, some internal search functions. Functions to populate a block
group based on the extent tree. The code is largely copy/paste from
the kernel with locking eliminated (i.e free_space_lock). It supports
reading/writing of both bitmap and extent based FST trees.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/ctree.h b/ctree.h
index 49f0f518..a6d6c3de 100644
--- a/ctree.h
+++ b/ctree.h
@@ -1071,6 +1071,17 @@ struct btrfs_block_group_cache {
 	u64 flags;
 	int cached;
 	int ro;
+	/*
+         * If the free space extent count exceeds this number, convert the block
+         * group to bitmaps.
+         */
+        u32 bitmap_high_thresh;
+        /*
+         * If the free space extent count drops below this number, convert the
+         * block group back to extents.
+         */
+        u32 bitmap_low_thresh;
+
 };
 
 struct btrfs_device;
@@ -2596,6 +2607,10 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 		      *root, struct btrfs_key *key, struct btrfs_path *p, int
 		      ins_len, int cow);
+int btrfs_search_slot_for_read(struct btrfs_root *root,
+                               const struct btrfs_key *key,
+                               struct btrfs_path *p, int find_higher,
+                               int return_any);
 int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path,
 		u64 iobjectid, u64 ioff, u8 key_type,
 		struct btrfs_key *found_key);