Btrfs: Use mount -o subvol to select the subvol directory instead of dev:

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index ffeee546a0d7..cd75c906048f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1064,6 +1064,12 @@ static inline int btrfs_set_root_name(struct btrfs_root *root,
         ((type *)(btrfs_leaf_data(leaf) + \
         btrfs_item_offset((leaf)->items + (slot))))
 
+/* mount option defines and helpers */
+#define BTRFS_MOUNT_SUBVOL              0x000001
+#define btrfs_clear_opt(o, opt)         o &= ~BTRFS_MOUNT_##opt
+#define btrfs_set_opt(o, opt)           o |= BTRFS_MOUNT_##opt
+#define btrfs_test_opt(sb, opt)         (BTRFS_SB(sb)->s_mount_opt & \
+                                         BTRFS_MOUNT_##opt)
 /* extent-tree.c */
 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
                          struct btrfs_root *root);