This is a leftover from 
312c89fbca06 ("btrfs: cleanup btrfs_mount()
using btrfs_mount_root()"), the mode was used for opening devices that's
not done here anymore.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
 {
        struct vfsmount *mnt_root;
        struct dentry *root;
-       fmode_t mode = FMODE_READ;
        char *subvol_name = NULL;
        u64 subvol_objectid = 0;
        int error = 0;
 
-       if (!(flags & SB_RDONLY))
-               mode |= FMODE_WRITE;
-
        error = btrfs_parse_subvol_options(data, &subvol_name,
                                        &subvol_objectid);
        if (error) {