Btrfs: add a flags field to btrfs_fs_info

We have a lot of random ints in btrfs_fs_info that can be put into flags.  This
is mostly equivalent with the exception of how we deal with quota going on or
off, now instead we set a flag when we are turning it on or off and deal with
that appropriately, rather than just having a pending state that the current
quota_enabled gets set to.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4071fe2..21f2b2d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1836,7 +1836,7 @@
 		}
 		sb->s_flags &= ~MS_RDONLY;
 
-		fs_info->open = 1;
+		set_bit(BTRFS_FS_OPEN, &fs_info->flags);
 	}
 out:
 	wake_up_process(fs_info->transaction_kthread);