Btrfs: remove duplicated ino cache's inode lookup

We're doing a unnecessary extra lookup of the ino cache's
inode when we already have it (and holding a reference)
during the process of saving the ino cache contents to disk.
Therefore remove this extra lookup.

Signed-off-by: Filipe David Borba Manana <[e-mail]>
Signed-off-by: Josef Bacik <[e-mail]>
Signed-off-by: Chris Mason <[e-mail]>

fs/btrfs/free-space-cache.c

···
 
 int btrfs_write_out_ino_cache(struct btrfs_root *root,
 			      struct btrfs_trans_handle *trans,
-			      struct btrfs_path *path)
+			      struct btrfs_path *path,
+			      struct inode *inode)
 {
 	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
-	struct inode *inode;
 	int ret;
 
 	if (!btrfs_test_opt(root, INODE_MAP_CACHE))
-		return 0;
-
-	inode = lookup_free_ino_inode(root, path);
-	if (IS_ERR(inode))
 		return 0;
 
 	ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
···
 #endif
 	}
 
-	iput(inode);
 	return ret;
 }
 

fs/btrfs/free-space-cache.h

···
 			struct btrfs_root *root);
 int btrfs_write_out_ino_cache(struct btrfs_root *root,
 			      struct btrfs_trans_handle *trans,
-			      struct btrfs_path *path);
+			      struct btrfs_path *path,
+			      struct inode *inode);
 
 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group);
 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,

fs/btrfs/inode-map.c

···
 	}
 	btrfs_free_reserved_data_space(inode, prealloc);
 
-	ret = btrfs_write_out_ino_cache(root, trans, path);
+	ret = btrfs_write_out_ino_cache(root, trans, path, inode);
 out_put:
 	iput(inode);
 out_release: