-extern int zvol_open(dev_t *devp, int flag, int otyp, cred_t *cr);
-extern int zvol_dump(dev_t dev, caddr_t addr, daddr_t offset, int nblocks);
-extern int zvol_close(dev_t dev, int flag, int otyp, cred_t *cr);
-extern int zvol_strategy(buf_t *bp);
-extern int zvol_read(dev_t dev, uio_t *uiop, cred_t *cr);
-extern int zvol_write(dev_t dev, uio_t *uiop, cred_t *cr);
-extern int zvol_aread(dev_t dev, struct aio_req *aio, cred_t *cr);
-extern int zvol_awrite(dev_t dev, struct aio_req *aio, cred_t *cr);
-extern int zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr,
- int *rvalp);
-extern int zvol_busy(void);
-extern void zvol_init(void);