btrfs: get fs_info from trans in btrfs_write_out_cache

We can read fs_info from the transaction and can drop it from the
parameters.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -3644,8 +3644,7 @@ int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
 
 		if (cache->disk_cache_state == BTRFS_DC_SETUP) {
 			cache->io_ctl.inode = NULL;
-			ret = btrfs_write_out_cache(fs_info, trans,
-						    cache, path);
+			ret = btrfs_write_out_cache(trans, cache, path);
 			if (ret == 0 && cache->io_ctl.inode) {
 				num_started++;
 				should_put = 0;
@@ -3800,8 +3799,7 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
 
 		if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
 			cache->io_ctl.inode = NULL;
-			ret = btrfs_write_out_cache(fs_info, trans,
-						    cache, path);
+			ret = btrfs_write_out_cache(trans, cache, path);
 			if (ret == 0 && cache->io_ctl.inode) {
 				num_started++;
 				should_put = 0;

fs/btrfs/free-space-cache.c

@@ -1369,11 +1369,11 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
 	goto out;
 }
 
-int btrfs_write_out_cache(struct btrfs_fs_info *fs_info,
-			  struct btrfs_trans_handle *trans,
+int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
 			  struct btrfs_block_group_cache *block_group,
 			  struct btrfs_path *path)
 {
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	struct inode *inode;
 	int ret = 0;

fs/btrfs/free-space-cache.h

@@ -55,8 +55,7 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
 int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
 			struct btrfs_block_group_cache *block_group,
 			struct btrfs_path *path);
-int btrfs_write_out_cache(struct btrfs_fs_info *fs_info,
-			  struct btrfs_trans_handle *trans,
+int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
 			  struct btrfs_block_group_cache *block_group,
 			  struct btrfs_path *path);
 struct inode *lookup_free_ino_inode(struct btrfs_root *root,